U.S. patent application number 10/575455 was filed with the patent office on 2007-06-14 for mesothelioma therapeutic agent.
This patent application is currently assigned to CHUGAI SEIYAKU KABUSHIKI KAISHA. Invention is credited to Yasuo Adachi, Tadamitsu Kishimoto, Norihiro Nishimoto, Koichi Takayama.
Application Number | 20070134242 10/575455 |
Document ID | / |
Family ID | 34463281 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070134242 |
Kind Code |
A1 |
Nishimoto; Norihiro ; et
al. |
June 14, 2007 |
Mesothelioma therapeutic agent
Abstract
The present invention provides a mesothelioma therapeutic agent
containing an interleukin-6 (IL-6) antagonist such as antibody to
IL-6 receptor (IL-6R), and a mesothelioma cell growth inhibitor
containing an IL-6 antagonist such as antibody to IL-6R.
Inventors: |
Nishimoto; Norihiro; (Osaka,
JP) ; Kishimoto; Tadamitsu; (Osaka, JP) ;
Adachi; Yasuo; (Osaka, JP) ; Takayama; Koichi;
(Fukuoka, JP) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
CHUGAI SEIYAKU KABUSHIKI
KAISHA
|
Family ID: |
34463281 |
Appl. No.: |
10/575455 |
Filed: |
October 15, 2004 |
PCT Filed: |
October 15, 2004 |
PCT NO: |
PCT/JP04/15674 |
371 Date: |
August 9, 2006 |
Current U.S.
Class: |
424/145.1 |
Current CPC
Class: |
C07K 2317/73 20130101;
A61K 45/06 20130101; A61P 35/00 20180101; C07K 16/248 20130101;
C07K 16/2866 20130101; C07K 2317/76 20130101; A61P 43/00 20180101;
C07K 2317/24 20130101 |
Class at
Publication: |
424/145.1 |
International
Class: |
A61K 39/395 20060101
A61K039/395 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2003 |
JP |
2003-358152 |
Claims
1. A mesothelioma therapeutic agent that contains an interleukin-6
(IL-6) antagonist as its active ingredient.
2. A mesothelioma therapeutic agent according to claim 1 wherein,
the mesothelioma is pleural mesothelioma.
3. A mesothelioma therapeutic agent according to claim 2 wherein,
the pleural mesothelioma is malignant pleural mesothelioma.
4. A mesothelioma therapeutic agent according to claim 1 wherein,
the IL-6 antagonist is antibody to IL-6 receptor.
5. A mesothelioma therapeutic agent according to claim 4 wherein,
the antibody to IL-6 receptor is monoclonal antibody to IL-6
receptor.
6. A mesothelioma therapeutic agent according to claim 4 wherein,
the antibody to IL-6 receptor is monoclonal antibody to human IL-6
receptor.
7. A mesothelioma therapeutic agent according to claim 4 wherein,
the antibody to IL-6 receptor is monoclonal antibody to mouse IL-6
receptor.
8. A mesothelioma therapeutic agent according to claim 4 wherein,
the antibody to IL-6 receptor is recombinant antibody.
9. A mesothelioma therapeutic agent according to claim 6 wherein,
the monoclonal antibody to human IL-6 receptor is PM-1
antibody.
10. A mesothelioma therapeutic agent according to claim 7 wherein,
the monoclonal antibody to mouse IL-6 receptor is MR16-1
antibody.
11. A mesothelioma therapeutic agent according to claim 4 wherein,
the antibody to IL-6 receptor is chimeric antibody, humanized
antibody or human antibody.
12. A mesothelioma therapeutic agent according to claim 11 wherein,
the humanized antibody to IL-6 receptor is humanized PM-1
antibody.
13. A growth inhibitor against mesothelioma cells that contains an
interleukin-6 (IL-6) antagonist as its active ingredient.
14. A growth inhibitor according to claim 13 wherein, the
mesothelioma is pleural mesothelioma.
15. A growth inhibitor according to claim 14 wherein, the pleural
mesothelioma is malignant pleural mesothelioma.
16. A growth inhibitor according to claim 13 wherein, the IL-6
antagonist is antibody to IL-6 receptor.
17. A growth inhibitor according to claim 16 wherein, the antibody
to IL-6 receptor is monoclonal antibody to IL-6 receptor.
18. A growth inhibitor according to claim 16 wherein, the antibody
to IL-6 receptor is monoclonal antibody to human IL-6 receptor.
19. A growth inhibitor according to claim 16 wherein, the antibody
to IL-6 receptor is monoclonal antibody to mouse IL-6 receptor.
20. A growth inhibitor according to claim 16 wherein, the antibody
to IL-6 receptor is recombinant antibody.
21. A growth inhibitor according to claim 18 wherein, the
monoclonal antibody to human IL-6 receptor is PM-1 antibody.
22. A growth inhibitor according to claim 19 wherein, the
monoclonal antibody to mouse IL-6 receptor is MR16-1 antibody.
23. A growth inhibitor according to claim 16 wherein, the antibody
to IL-6 receptor is chimeric antibody, humanized antibody or human
antibody.
24. A growth inhibitor according to claim 23 wherein, the humanized
antibody to IL-6 receptor is humanized PM-1 antibody.
Description
TECHNICAL FIELD
[0001] The present invention relates to a novel mesothelioma
therapeutic agent and mesothelioma cell inhibitor.
BACKGROUND ART
[0002] Mesothelioma is a tumor that occurs in the mesothelium that
covers the surface of the pleura, peritoneum and pericardium that
respectively envelop the organs of the chest cavity such as the
lungs and heart, and abdominal organs such as the digestive tract
and liver. In the case of diffuse pleural mesothelioma, chest pain
is caused by invasion of the intercostals nerves on the side of the
chest wall pleura, and respiratory and circulatory disorders may
occur due to tumor growth and accumulation of pleural fluid in the
pleura on the organ side (Takagi, Journal of Clinical and
Experimental Medicine, (March Supplement), "Respiratory Diseases",
pp. 469-472, 1999). There is eventually proliferation into the
adjacent mediastinal organs, progressing to direct invasion of the
heart or development into the abdominal cavity by means of the
diaphragm, or there may be development outside the chest cavity as
a result of additional lymphatic or circulatory metastasis
(ibid).
[0003] In the U.S., diffuse pleural mesothelioma is reported to
occur in 3,000 persons annually, the number of cases began to
increase prominently in the 1980s, and is frequently observed in
men in their sixties, with the incidence in men being roughly five
times that in women (Takagi, Journal of Clinical and Experimental
Medicine (March Supplement), "Respiratory Diseases", pp. 469-472,
1999). According to recent reports in the U.S. and Europe, the
incidence of mesothelioma is demonstrating a rapidly increasing
trend, and based on epidemiological statistics from the U.K. in
1995, the number of deaths from mesothelioma is predicted to
continue to increase over the next 25 years, and in the worst
possible scenario, has been indicated as having a risk to the
extent of accounting for 1% of all deaths among men born in the
1940s (Nakano, Respiration, Vol. 18, No. 9, pp. 916-925, 1999).
[0004] Numerous different classifications of the clinical disease
stages have been used for mesothelioma, and since the methods for
classifying the disease stage used differ, previous therapeutic
reports on mesothelioma have encountered difficulties when
comparing the results of treatment (Nakano, Respiration, Vol. 18,
No. 9, pp. 916-925, 1999). An international TNM classification for
malignant pleural mesothelioma in 1995 by the International
Mesothelioma Interest Group (IMIG) (Nakano, Respiration, Vol. 18,
No. 9, pp. 916-925, 1999).
[0005] In addition, malignant mesothelioma has a causative
relationship with exposure to asbestos, and this has also been
demonstrated in animal experiments (Tada, Journal of Clinical and
Experimental Medicine (March Supplement), "Respiratory Diseases",
pp. 406-408, 1999). Asbestos that has been inhaled into the
respiratory tract reaches a location directly beneath the pleura
where a tumor eventually develops due to chronic irritation for at
least about 20 years, and this tumor spreads in a thin layer over
the entire surface of the pleura (Takagi, Journal of Clinical and
Experimental Medicine (March Supplement), "Respiratory Diseases",
pp. 469-472, 1999). Consequently, although malignant mesothelioma
is classified as an asbestos-related disease, not all malignant
mesothelioma is caused by asbestos, and well-documented exposure is
only observed in about half of all patients (Tada, Journal of
Clinical and Experimental Medicine (March Supplement), "Respiratory
Diseases", pp. 406-408, 1999).
[0006] Malignant pleural mesothelioma is resistant to treatment, is
associated with an extremely poor prognosis, and requires that
countermeasures be taken immediately (Nakano, Respiration, Vol. 18,
No. 9, pp. 916-925, 1999). For example, although the folic acid
antagonist, methotrexate (MTX), has a satisfactory efficacy rate of
37% in large-dose single treatment in combination with leucovin,
its use has not proliferated due to the technical difficulty
associated with application to mesothelioma that causes retention
of a large amount of pleural fluid (Nakano, Journal of Clinical and
Experimental Medicine (March Supplement), "Respiratory Diseases",
pp. 570-573, 2003). In addition, although pleuropulmonary excision
and pleurectomy are performed for diffuse pleural mesothelioma,
there is increased susceptibility to relapse following treatment,
and the post-surgical local relapse rate in particular is high at
35-43% (Takagi, Journal of Clinical and Experimental Medicine
(March Supplement), "Respiratory Diseases", pp. 469-472, 1999).
[0007] Numerous human mesothelioma cell lines and several mouse
mesothelioma cell lines are known to express IL-6 in vitro, and in
mice transplanted with mouse mesothelioma cell line AB22, which
expresses a high level of IL-6, IL-6 has been reported to be
detected in serum prior to cancer cell growth, clinical symptoms
and changes in peripheral blood lymphocyte tissue
(Bielefeldt-Ohmann, Cancer Immunol. Immunother. 40: 241-250, 1995).
In addition, serum IL-6 levels in patients with malignant pleural
mesothelioma are higher in comparison with pulmonary adenoma
patients complicated with pleural effusion, and with respect to
thrombocytosis, which is one of the clinical symptoms of malignant
pleural mesothelioma, there is known to be a remarkable correlation
between serum IL-6 levels and platelet counts (Nakano, British
Journal of Cancer 77(6): 907-912, 1998). Moreover, the tumor cells
of pleural mesothelioma patients express high levels of IL-6, and
IL-6 levels in the serum have been reported to increase prior to
death (Higashihara, Cancer, Oct. 15, 1992, Vol. 70, No. 8, pp.
2105-2108).
[0008] As a result of administering rat anti-mouse IL-6 antibody
(6B4) to mouse transplanted with AB22 at the rate of twice a week,
Bielefeldt-Ohmann, et al. reported that effects were observed that
considerably diminished the onset and progression of clinical
symptoms (Bielefeldt-Ohmann, Cancer Immunol. Immunother. 40:
241-250, 1995). However, according to a report by Bielefeldt,
anti-IL-6 antibody does not have a direct growth inhibitory effect
on AB22 in vitro, there were no differences observed in the
postmortem appearances of mice treated with anti-IL-6 antibody and
those not treated with said antibody, and tumor masses of
considerable size were observed even in the treated mice
(Bielefeldt-Ohmann, Cancer Immunol. Immunother. 40: 241-250, 1995).
Namely, growth inhibition of mesothelioma by anti-IL-6 antibody has
not been known both in vitro and in vivo.
[0009] Takagi, Journal of Clinical and Experimental Medicine (March
Supplement), "Respiratory Diseases", pp. 469-472, 1999
[0010] Nakano, Respiration, Vol. 18, No. 9, pp. 916-925, 1999
[0011] Tada, Journal of Clinical and Experimental Medicine (March
Supplement), "Respiratory Diseases", pp. 406-408, 1999
[0012] Nakano, Journal of Clinical and Experimental Medicine (March
Supplement), "Respiratory Diseases", pp. 570-573, 2003
[0013] Bielefeldt-Ohmann, Cancer Immunol. Immunother. 40: 241-250,
1995
[0014] Higashihara, Cancer, Oct. 15, 1992, Vol. 70, No. 8, pp.
2105-2108
DISCLOSURE OF THE INVENTION
[0015] IL-6 antagonists were not known to act directly on
mesothelioma and demonstrate growth inhibitory effects. An object
of the present invention is to provide a novel mesothelioma
therapeutic agent (mesothelioma cell growth inhibitor) that
contains an IL-6 antagonist as its active ingredient.
[0016] As a result of conducting extensive studies to develop a
novel mesothelioma therapeutic agent that inhibits the growth of
mesothelioma cells, the inventor of the present invention obtained
the novel finding that the growth of mesothelioma cells can be
inhibited by inhibiting or interrupting signal transmission
relating to IL-6, thereby leading to completion of the present
invention.
[0017] Thus, the present invention provides a mesothelioma
therapeutic agent that contains an interleukin-6 (IL-6) antagonist
as its active ingredient.
[0018] In addition, the present invention also provides a growth
inhibitor against mesothelioma cells that contains an interleukin-6
(IL-6) antagonist as its active ingredient.
[0019] The aforementioned mesothelioma is, for example, pleural
mesothelioma, and more specifically, malignant pleural
mesothelioma. Diffuse pleural mesothelioma is included in malignant
pleural mesothelioma.
[0020] The aforementioned IL-6 antagonist is, for example, an
antibody to IL-6 or an antibody to IL-6 receptor, and preferably a
monoclonal antibody to IL-6 receptor. The aforementioned antibody
to IL-6 receptor is particularly preferably a monoclonal antibody
to human IL-6 receptor such as PM-1 antibody, or a monoclonal
antibody to mouse IL-6 receptor such as MR16-1 antibody. The
aforementioned antibody to IL-6 receptor is preferably a
recombinant antibody.
[0021] The aforementioned antibody to IL-6 receptor may be a
chimeric antibody, humanized antibody or human antibody. In the
present invention, a particularly preferable antibody is humanized
PM-1 antibody.
[0022] The present invention can also be in the forms indicated
below.
(1) The use of an interleukin-6 (IL-6) antagonist to produce a
mesothelioma therapeutic agent.
(2) The use according to (1) above in which the mesothelioma is
pleural mesothelioma.
(3) The use according to (2) above wherein the pleural mesothelioma
is malignant pleural mesothelioma.
(4) The use according to any of (1) through (3) above wherein the
IL-6 antagonist is an antibody to IL-6 receptor.
(5) The use according to (4) above wherein the antibody to IL-6
receptor is a monoclonal antibody to IL-6 receptor.
(6) The use according to (4) above wherein the antibody to IL-6
receptor is a monoclonal antibody to human IL-6 receptor.
(7) The use according to (4) above wherein the antibody to IL-6
receptor is a monoclonal antibody to mouse IL-6 receptor.
(8) The use according to any of (4) through (7) above wherein the
antibody to IL-6 receptor is a recombinant antibody.
(9) The use according to (6) above wherein the monoclonal antibody
to human IL-6 receptor is PM-1 antibody.
(10) The use according to (7) above wherein the monoclonal antibody
to mouse IL-6 receptor is MR16-1 antibody.
(11) The use according to any of (4) through (10) above wherein the
antibody to IL-6 receptor is a chimeric antibody, humanized
antibody or human antibody to IL-6 receptor.
(12) The use according to (11) above wherein the humanized antibody
to IL-6 receptor is humanized PM-1 antibody.
(13) The use of an interleukin-6 (IL-6) antagonist to produce a
growth inhibitor against mesothelioma cells.
(14) The use according to (13) above in which the mesothelioma is
pleural mesothelioma.
(15) The use according to (14) above wherein the pleural
mesothelioma is malignant pleural mesothelioma.
(16) The use according to any of (13) through (15) above wherein
the IL-6 antagonist is an antibody to IL-6 receptor.
(17) The use according to (16) above wherein the antibody to IL-6
receptor is a monoclonal antibody to IL-6 receptor.
(18) The use according to (16) above wherein the antibody to IL-6
receptor is a monoclonal antibody to human IL-6 receptor.
(19) The use according to (16) above wherein the antibody to IL-6
receptor is a monoclonal antibody to mouse IL-6 receptor.
(20) The use according to any of (16) through (19) above wherein
the antibody to IL-6 receptor is a recombinant antibody.
(21) The use according to (18) above wherein the monoclonal
antibody to human IL-6 receptor is PM-1 antibody.
(22) The use according to (19) above wherein the monoclonal
antibody to mouse IL-6 receptor is MR16-1 antibody.
(23) The use according to any of (16) through (22) above wherein
the antibody to IL-6 receptor is a chimeric antibody, humanized
antibody or human antibody to IL-6 receptor.
(24) The use according to (23) above wherein the humanized antibody
to IL-6 receptor is humanized PM-1 antibody.
[0023] The present invention can also adopt the forms indicated
below.
(1) A treatment method for mesothelioma comprising: administering
an interleukin-6 (IL-6) antagonist to a subject requiring that
treatment.
(2) The method according to (1) above wherein the mesothelioma is
pleural mesothelioma.
(3) The method according to (2) above wherein the pleural
mesothelioma is malignant pleural mesothelioma.
(4) The method according to any of (1) through (3) above wherein
the IL-6 antagonist is an antibody to IL-6 receptor.
(5) The method according to (4) above wherein the antibody to IL-6
receptor is a monoclonal antibody to IL-6 receptor.
(6) The method according to (4) above wherein the antibody to IL-6
receptor is a monoclonal antibody to human IL-6 receptor.
(7) The method according to (4) above wherein the antibody to IL-6
receptor is a monoclonal antibody to mouse IL-6 receptor.
(8) The method according to any of (4) through (7) above wherein
the antibody to IL-6 receptor is a recombinant antibody.
(9) The method according to (6) above wherein the monoclonal
antibody to human IL-6 receptor is PM-1 antibody.
(10) The method according to (7) above wherein the monoclonal
antibody to mouse IL-6 receptor is MR16-1 antibody.
(11) The method according to any of (4) through (10) above wherein
the antibody to IL-6 receptor is a chimeric antibody, humanized
antibody or human antibody to IL-6 receptor.
(12) The method according to (11) above wherein the humanized
antibody to IL-6 receptor is humanized PM-1 antibody.
(13) A method for inhibiting the growth of mesothelioma cells
comprising: administering an interleukin-6 (IL-6) antagonist to a
subject requiring that inhibition.
(14) The method according to (13) above in which the mesothelioma
is pleural mesothelioma.
(15) The method according to (14) above wherein the pleural
mesothelioma is malignant pleural mesothelioma.
(16) The method according to any of (13) through (15) above wherein
the IL-6 antagonist is an antibody to IL-6 receptor.
(17) The method according to (16) above wherein the antibody to
IL-6 receptor is a monoclonal antibody to IL-6 receptor.
(18) The method according to (16) above wherein the antibody to
IL-6 receptor is a monoclonal antibody to human IL-6 receptor.
(19) The method according to (16) above wherein the antibody to
IL-6 receptor is a monoclonal antibody to mouse IL-6 receptor.
(20) The method according to any of (16) through (19) above wherein
the antibody to IL-6 receptor is a recombinant antibody.
(21) The method according to (18) above wherein the monoclonal
antibody to human IL-6 receptor is PM-1 antibody.
(22) The method according to (19) above wherein the monoclonal
antibody to mouse IL-6 receptor is MR16-1 antibody.
(23) The method according to any of (16) through (22) above wherein
the antibody to IL-6 receptor is a chimeric antibody, humanized
antibody or human antibody to IL-6 receptor.
(24) The method according to (23) above wherein the humanized
antibody to IL-6 receptor is humanized PM-1 antibody.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a graph that shows the results of Example 1 by
indicating the productivities of IL-6 by various malignant
mesothelioma cell lines.
[0025] FIG. 2 is a graph that shows the results of Example 2 by
indicating the productivities (lack thereof) of IL-6 receptor
(IL-6R) by various malignant mesothelioma cell lines. Furthermore,
GAPDH indicates the amount of mRNA of GAPDH
(glyceraldehyde-3-phosphate dehydrogenase) used as an internal
control.
[0026] FIG. 3 is a graph that shows the results of Example 3,
wherein the production of vascular endothelial growth factor (VEGF)
by malignant mesothelioma cell lines H2052 and H2452 is induced by
IL-6 and IL-6R.
[0027] FIG. 4 is a graph that shows the results of Example 4 in
which a similar experiment to Example 3 was conducted for malignant
mesothelioma cell line H28 by indicating that this cell line
produces vascular endothelial growth factor (VEGF) without
requiring induction by IL-6/IL-6R.
[0028] FIG. 5 is a graph that shows the results of Example 5,
wherein in contrast to phosphorylation of STAT3 due to stimulation
by IL-6 being promoted in cell line H2025, in which production of
VEGF is induced by IL-6, phosphorylation of STAT3 due to
stimulation by IL-6 is not promoted in cell line H28, in which
production of VEGF is not induced by IL-6.
[0029] FIG. 6 is a graph that shows the results of Example 6,
wherein in contrast to expression of SOCS3 due to stimulation by
IL-6 and IL-6R being induced in cell line H2025, in which
production of VEGF is induced by IL-6, SOCS3 is non-inductively
expressed in cell line H28, in which production of VEGF is not
induced by IL-6.
[0030] FIG. 7 is a drawing showing the structure of a promoter of
plasmids pGL3-VEGF and pGL3-VEGFmut along with its vicinity used in
Example 7.
[0031] FIG. 8 is a graph that shows the results of Example 7,
wherein in a system in which VEGF promoter is coupled to luciferase
reporter gene, in the case of altering the p-STAT3 binding site
within the VEGF promoter, activation of the VEGF promoter by IL-6
does not occur.
[0032] FIG. 9 is a schematic drawing showing the mechanism of
induction of VEGF promoter (production of VEGF) due to stimulation
by IL-6 in cell line H2052 as predicted from the results of
Examples 5 through 7.
[0033] FIG. 10 is a graph that shows the results of Example 8,
wherein the growth of cell line H2052 increases IL-6
concentration-dependently in the presence of IL-6R.
[0034] FIG. 11 is a graph that shows the results of Example 9,
wherein promotion of the growth of cell line H2052 by IL-6 and
IL-6R is inhibited by MRA.
[0035] FIG. 12 is a graph that shows the results of Example 10,
wherein the growth of cell line H226 increases IL-6
concentration-dependently in the presence of IL-6R, and that MRA
demonstrates inhibitory effects on that growth.
[0036] FIG. 13 is a graph that shows the results of Experiment 8 by
indicating that the growth of cell line H226 increases IL-6
concentration-dependently in the presence of IL-6R.
[0037] FIG. 14 is a graph that shows the results of Example 11,
wherein growth promotion of malignant mesothelioma cell lines H2052
and H226 by IL-6 and soluble IL-6 receptor is inhibited by
humanized PM-1 antibody.
[0038] FIG. 15 is a graph that shows the results of Example 12,
wherein induction of VEGF production by IL-6 stimulation in the
malignant mesothelioma cell lines MSTO, H226, H2052 and H2452 is
inhibited by humanized PM-1 antibody.
[0039] FIG. 16 is a graph that shows the results of Example 13,
wherein phosphorylation of STAT3 induced by IL-6/soluble IL-6R
stimulation in the cell lines H2052 and H2452 is inhibited by
humanized PM-1 antibody.
[0040] FIG. 17 is a graph that shows the results of Example 14,
wherein promotion of the growth of the cell lines H2052 and H226 by
IL-6 and soluble IL-6R stimulation is not inhibited by anti-VEGF
antibody.
BEST MODE FOR CARRYING OUT THE INVENTION
[0041] IL-6 is a cytokine also referred to as B cell stimulating
factor 2 (BSF2) or interferon .beta.2. IL-6 was initially
discovered to be differentiation factor involved in activation of B
lymphocytic cells (Hirano, T. et al., Nature (1986) 324, 73-76),
after which it was determined to be a multifunctional cytokine
having effects on the functions of various cells (Akira, S. et al.,
Adv. In Immunology (1993) 54, 1-78). IL-6 has also been reported to
induce maturation of T lymphocytic cells (Lotz, M. et al., J. Exp.
Med. (1988) 167, 1253-1258).
[0042] IL-6 transmits its biological activity by means of various
proteins on cells. One of these is the ligand-binding protein of
IL-6 receptors having a molecular weight of about 80 kD (Taga, T.
et al., J. Exp. Med. (1987) 166, 967-981; Yamasaki, K. et al.,
Science (1987) 241, 825-828). In addition to existing in a
membrane-bound form that is expressed on the cell membrane by
penetrating the cell membrane, IL-6 receptors also exist as soluble
IL-6 receptors mainly composed of an extracellular region.
[0043] Another of these a membrane protein gp130 having a molecular
weight of about 130 kD that is involved in the signal transmission
of non-ligand binding. IL-6 and IL-6 receptors form an IL-6/IL-6
receptor complex, and as a result of subsequently binding with
gp130, the biological activity of IL-6 is transmitted into cells
(Taga, T. et al., Cell (1989) 58, 573-581).
[0044] IL-6 antagonists are substances that inhibit the
transmission of the biological activity of IL-6. Known examples of
these IL-6 antagonists include antibody to IL-6 (anti-IL-6
antibody), antibody to IL-6 receptors (anti-IL-6 receptor
antibody), antibody to gp130 (anti-gp130 antibody), IL-6 variant,
and IL-6 or IL-6 receptor partial peptide.
[0045] There have been several reports regarding anti-IL-6 receptor
antibody (Novick, D. et al., Hybridoma (1991) 10, 137-146; Huang,
Y. W. et al., Hybridoma (1993) 12, 621-630; International
Unexamined Patent Publication No. WO 95-09873; French Unexamined
Patent Publication No. FR 2694767, and U.S. Pat. No. 521,628).
Humanized PM-1 antibody is known to be obtained by transplanting
the complementarity determining region (CDR) of one of these in the
form of mouse anti-PM-1 (Hirata, Y. et al., J. Immunol. (1989) 143,
2900-2906) to human antibody (International Unexamined Patent
Publication No. WO 92-19759).
[0046] The aforementioned IL-6 antagonist is preferably an antibody
to IL-6 receptor, and more preferably a monoclonal antibody to
human IL-6 receptor or monoclonal antibody to mouse IL-6 receptor.
An example of the aforementioned monoclonal antibody to human IL-6
receptor is PM-1 antibody, while an example of monoclonal antibody
to mouse IL-6 receptor is MR16-1 antibody. The aforementioned
antibody is preferably a chimeric antibody, humanized antibody or
human antibody, an example of which is humanized PM-1 antibody.
[0047] There are particular limitations on the origin, type or form
of the IL-6 antagonist used in the present invention provided it
inhibits the growth of mesothelioma cells and is useful as an
active ingredient of a mesothelioma therapeutic agent.
[0048] IL-6 antagonists are substances that inhibit the biological
activity of IL-6 by interrupting signal transmission by IL-6. IL-6
antagonists are preferably substances that have inhibitory action
against the binding of IL-6, IL-6 receptor and gp130. Examples of
IL-6 antagonists include anti-IL-6 antibody, anti-IL-6 receptor
antibody, anti-gp130 antibody, IL-6 variants, soluble IL-6 receptor
variants, IL-6 receptor partial peptides and low molecular weight
substances demonstrating similar activity.
[0049] Anti-IL-6 antibody used in the present invention can be
obtained as a polyclonal or monoclonal antibody using known
methods. Monoclonal antibody of mammalian origin is particularly
preferable for the anti-IL-6 antibody used in the present
invention. Examples of monoclonal antibodies of mammalian origin
include those produced by hybridomas and those produced by hosts
transformed with an expression vector containing antibody gene
using genetic engineering techniques. This antibody interrupts the
transmission of the biological activity of IL-6 to cells as a
result of inhibiting binding of IL-6 to IL-6 receptors by binding
with IL-6.
[0050] Examples of these antibodies include MH166 (Matsuda, T. et
al., Eur. J. Immunol. (1998) 18, 951-956), and SK2 antibody (Sato,
K. et al., 21st General Meeting of the Japanese Society for
Immunology, Academic Record (1991) 21, 166).
[0051] Anti-IL-6 antibody-producing hybridoma can basically be
produced in the manner described below using known technology.
Namely, this antibody can be produced by using IL-6 as a
sensitizing antigen, immunizing with this in accordance with
ordinary immunization methods, fusing the resulting immunocytes
with known host cells according to ordinary cell fusion methods,
and then screening for cells that produce monoclonal antibody
according to ordinary screening methods.
[0052] More specifically, production of IL-6 antibody should be
carried out in the manner described below. Human IL-6 used as
sensitizing antigen for acquiring antibody is obtained by using the
IL-6 gene/amino acid sequence disclosed in Eur. J. Biochem. (1987)
168, 543-550; J. Immunol. (1988) 140, 1534-1541; or, Agr. Biol.
Chem. (1990) 54, 2685-2688.
[0053] After inserting the IL-6 gene sequence into a known
expression vector system and transforming suitable host cells, the
target IL-6 protein is purified by known methods from the host
cells or culture supernatant, followed by using this purified IL-6
protein as a sensitizing antigen. In addition, a fused protein
consisting of IL-6 protein and another protein may also be used as
sensitizing antigen.
[0054] The anti-IL-6 receptor antibody used in the present
invention can be obtained in the form of a polyclonal antibody or
monoclonal antibody using known means. Monoclonal antibody of
mammalian origin is particularly preferable for the anti-IL-6
receptor antibody used in the present invention. Examples of
monoclonal antibody originating in mammalian cells include those
produced by hybridomas and those produced in a host transformed
with an expression vector that contains antigen gene by genetic
engineering techniques. As a result of this antibody binding to
IL-6 receptors, binding of IL-6 to IL-6 receptors is inhibited,
thereby interrupting the transmission of the biological activity of
IL-6 to cells.
[0055] Examples of these antibodies include MR16-1 antibody
(Tamura, T. et al., Proc. Natl. Acad. Sci. USA (1993) 90,
11924-11928), PM-1 antibody (Hirata, Y. et al., J. Immunol. (1989)
143, 2900-2906), AUK12-20 antibody, AUK64-7 and AUK146-15 antibody
(International Unexamined Patent Publication No. WO 92-19759).
Among these, PM-1 antibody is particularly preferable for use as
the antibody.
[0056] Furthermore, a PM-1 antibody-producing hybridoma cell line
has been internationally deposited based on the Budapest Treaty
under the designation FERM BP-2998 on Jul. 12, 1989 at the
International Patent Organism Depository of the National Institute
of Advanced Industrial Science and Technology (Tsukuba Central 6,
1-1-1 Higashi, Tsukuba, Ibaraki, Japan) as PM-1. In addition, an
MR16-1 antibody-producing hybridoma cell line has been
internationally deposited based on the Budapest Treaty under the
designation FERM BP-5875 on Mar. 13, 1997 at the International
Patent Organism Depository of the National Institute of Advanced
Industrial Science and Technology (Tsukuba Central 6, 1-1-1
Higashi, Tsukuba, Ibaraki, Japan) as Rat-mouse hybridoma
MR16-1.
[0057] Anti-IL-6 receptor monoclonal antibody-producing hybridoma
can basically be produced in the manner described below using known
technology. Namely, this hybridoma can be produced by using IL-6
receptor as sensitizing antigen, immunizing with this in accordance
with ordinary immunization methods, fusing the resulting
immunocytes with known host cells according to ordinary cell fusion
methods, and screening for cells that produce monoclonal antibody
according to known screening methods.
[0058] More specifically, anti-IL-6 receptor antibody should be
produced in the manner described below. For example, human IL-6
receptor used as sensitizing antigen for acquisition of antibody is
obtained by using the IL-6 receptor gene/amino acid sequence
disclosed in European Unexamined Patent Publication No. EP 325474,
while mouse IL-6 receptor is obtained by using the IL-6 receptor
gene/amino acid sequence disclosed in Japanese Unexamined Patent
Publication No. 3-155795.
[0059] There are two types of IL-6 receptor protein consisting of
that which is expressed on the cell membrane and that which is
released from the cell membrane (soluble IL-6 receptor) (Yasukawa,
K. et al., J. Biochem. (1990) 108, 673-676). Soluble IL-6 receptor
antibody is substantially composed of the extracellular region of
IL-6 receptor that binds to the cell membrane, and differs from
membrane-bound IL-6 receptor in that it is missing a cell
membrane-penetrating region or cell membrane-penetrating region and
intracellular region. IL-6 receptor protein may use either IL-6
receptor provided it can be used as sensitizing antigen for
producing the anti-IL-6 receptor antibody used in the present
invention.
[0060] After inserting the gene sequence of IL-6 receptor into a
known expression vector system to transform suitable host cells,
the target IL-6 receptor is purified by known methods from the host
cells or culture supernatant followed by using the purified IL-6
receptor protein as sensitizing antigen. In addition, a fused
protein consisting of cells that express IL-6 receptor or IL-6
receptor protein and another protein may also be used as
sensitizing antigen.
[0061] Escherichia coli (E. coli) containing plasmid pIBIBSF2R that
contains cDNA encoding human IL-6 receptor has been internationally
deposited based on the Budapest Treaty under the deposit number
FERM BP-2232 on Jan. 9, 1989 at the International Patent Organism
Depository of the National Institute of Advanced Industrial Science
and Technology (Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki,
Japan) as HB101-pIBIBSF2R.
[0062] Anti-gp130 antibody used in the present invention can be
obtained in the form of polyclonal antibody or monoclonal antibody
using known means. Monoclonal antibody of mammalian origin is
particularly preferable for the anti-gp130 antibody used in the
present invention. Monoclonal antibodies of mammalian origin
include those produced by hybridomas and those produced in a host
transformed with an expression vector that contains antibody gene
by genetic engineering techniques. This antibody inhibits binding
of IL-6/IL-6 receptor complex to gp130 and interrupts the
transmission of the biological activity of IL-6 to cells by binding
with gp130.
[0063] Examples of these antibodies include AM64 antibody (Japanese
Unexamined Patent Publication No. 3-219894), 4B11 antibody, 2H4
antibody (U.S. Pat. No. 5,571,513) and B-P8 antibody (Japanese
Unexamined Patent Publication No. 8-291199).
[0064] Anti-gp130 monoclonal antibody-producing hybridoma can
basically be produced in the manner described below using known
technology. Namely, this hybridoma can be produced by using gp130
as a sensitizing antigen, immunizing with this in accordance with
ordinary immunization methods, fusing the resulting immunocytes
with known host cells according to ordinary cell fusion methods,
and screening for cells that produce monoclonal antibody according
to ordinary screening methods.
[0065] More specifically, monoclonal antibody should be produced in
the manner described below. For example, gp130 used as sensitizing
antigen for acquiring antibody is obtained by using the gp130
gene/amino acid sequence disclosed in European Unexamined Patent
Publication No. EP 411946.
[0066] After inserting the gene sequence of gp130 into a known
expression vector system to transform suitable host cells, the
target gp130 protein is purified from the host cells or culture
supernatant by known methods, followed by using the purified gp130
receptor protein as sensitizing antigen. In addition, a fused
protein consisting of cells expressing gp130 or gp130 protein and
another protein may also be used as sensitizing antigen.
[0067] Although there are no particular limitations on the mammal
immunized with sensitizing antigen, it is preferably selected in
consideration of compatibility with the host cells used for cell
fusion, typical examples of which include rodents such as mice,
rats and hamsters.
[0068] Immunization of the animal with sensitizing antigen is
carried out in accordance with known methods. As a typical example
of such a method, immunization is preferably carried out by
injecting sensitizing antigen into the abdominal cavity or beneath
the skin of a mammal. More specifically, a suspension of
sensitizing antigen diluted to a suitable amount with
phosphate-buffered saline (PSB) or physiological saline is mixed
with a suitable amount of an ordinary adjuvant such as Freund's
complete adjuvant as desired followed by emulsifying and
administering several times to the mammal every 4 to 21 days. In
addition, a suitable carrier can be used when immunizing with the
sensitizing antigen.
[0069] After confirming that immunization has been carried out in
this manner and the antibody level in serum has risen to a desired
level, immunocytes are removed from the mammal and used for cell
fusion. Spleen cells are a particularly preferable example of
immunocytes used for cell fusion.
[0070] Various known cell lines such as P3X6Ag8.653 (Kearney, J. F.
et al., J. Immunol. (1979) 123, 1548-1550), P3X63Ag8U.1 (Current
Topics in Microbiology and Immunology (1978) 81, 1-7), NS-1
(Kohler, G. and Milstein, C., Eur. J. Immunol. (1976) 6, 511-519),
MPC-11 (Margulies, D. H. et al., Cell (1976) 8, 405-415, SP2/0
(Shulman, M. et al., Nature (1978) 276, 269-270), F0 (de St. Groth,
S. F. et al., J. Immunol. Methods (1980) 35, 1-21), S194
(Trowbridge, I. S., J. Exp. Med. (1978) 148, 313-323) or R210
(Galfre, G. et al., Nature (1979) 277, 131-133) are already
suitably used as mammalian myeloma cells serving as the other host
cells fused with the aforementioned immunocytes.
[0071] Fusion of the aforementioned immunocytes and myeloma cells
can basically be carried out in compliance with known methods such
as the method of Milstein, et al. (Kohler, G. and Milstein, C.,
Methods Enzymol. (1981) 73, 3-46).
[0072] More specifically, the aforementioned cell fusion is carried
out, for example, in an ordinary nutritive culture liquid in the
presence of a cell fusion promoter. Examples of fusion promoters
that are used include polyethylene glycol (PEG) and Sendai virus
(HVJ), and an assistant such as dimethylsulfoxide can also be added
to enhance fusion efficiency as desired.
[0073] The ratio of immunocytes and myeloma cells used is
preferably 1 to 10 times more immunocytes than myeloma cells.
Examples of culture liquids that can be used for the aforementioned
cell fusion include RPMI1640 culture liquid preferable for growth
of the aforementioned myeloma cells, MEM culture liquid and other
ordinary culture liquids used for this type of cell culturing.
Moreover, a serum supplement such as fetal calf serum (FCS) can
also be used in combination with the aforementioned culture
liquid.
[0074] Cell fusion is carried out by thoroughly mixing
predetermined amounts of the aforementioned immunocytes and myeloma
cells in the aforementioned culture liquid, adding PEG solution,
such as PEG solution having an average molecular weight of about
1000 to 6000 and pre-warmed to 37.degree. C., normally at a
concentration of 30 to 60% (w/v), and then mixing to form the
target fused cells (hybridoma). Continuing, cell fusion agents and
so forth that are detrimental to hybridoma development can be
removed by repeating the procedure consisting of sequentially
adding suitable culture liquid and then centrifuging to remove the
supernatant.
[0075] The hybridoma is selected by culturing in an ordinary
selective culture liquid such as HAT culture liquid (culture liquid
containing hypoxanthine, aminopterin and thymidine). Culturing in
said HAT culture liquid is continued for a duration, which is
normally from several days to several weeks, that is sufficient for
destroying those cells other than the target hybridoma (non-fused
cells). Next, hybridoma that produces the target antibody is then
screened and cloned by carrying out ordinary limiting dilution
methods.
[0076] In addition to obtaining the aforementioned hybridoma by
immunizing animals other than humans with antigen, a desired human
antibody having binding activity with a desired antigen or
antigen-expressing cells can be obtained by sensitizing human
lymphocytes with a desired antigen protein or antigen-expressing
cells in vitro, and then fusing the sensitized B lymphocytes with
myeloma cells such as U266 (refer to Japanese Examined Patent
Publication No. 1-59878). Moreover, a desired human antibody may
also be acquired in accordance with the aforementioned method by
administering antigen or antigen-expressing cells into a transgenic
animal having a repertoire of human antibody genes (refer to
International Unexamined Patent Publications Nos. WO 93/12227, WO
92/03918, WO 94/02602, WO 94/25585, WO 96/34096 or WO
96/33735).
[0077] Hybridoma that produces monoclonal antibody produced in this
manner can be sub-cultured in ordinary culture liquid and stored in
liquid nitrogen for a long period of time.
[0078] A method in which the hybridoma is cultured in accordance
with ordinary methods and obtained in the form of the culture
supernatant, or a method in which the hybridoma is grown by
administering to a mammal that is compatible therewith followed by
obtaining the form of ascites, can be employed to acquire
monoclonal antibody from the hybridoma. The former method is
suitable for obtaining highly pure antibody, while the latter
method is suitable for producing antibody in large volume.
[0079] For example, production of anti-IL-6 receptor
antibody-producing hybridoma can be carried out according to the
method disclosed in Japanese Unexamined Patent Publication No.
3-139293. This can be carried out using a method in which the
PM-1-producing hybridoma internationally deposited based on the
Budapest Treaty under the designation FERM BP-2998 on Jul. 12, 1989
at the International Patent Organism Depository of the National
Institute of Advanced Industrial Science and Technology (Tsukuba
Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, Japan) is injected into
the abdominal cavity of BALB/c mice to obtain ascites followed by
purification of PM-1 antibody from the ascites, or a method in
which said hybridoma is cultured in a medium such as 10% fetal calf
serum, RPMI1640 medium containing 5% BM-Condimed H1
(Boehringer-Mannheim), hybridoma SFM medium (Gibco-BRL) or PFHM-11
medium (Gibco-BRL), followed by purification of PM-1 antibody from
the culture supernatant.
[0080] Recombinant antibody produced using gene recombination
technology by cloning antibody gene from a hybridoma, incorporating
in a suitable vector and then inserting into a host can be used as
monoclonal antibody in the present invention (refer to, for
example, Borrebaeck, C. A. K. and Larrick, J. W., Therapeutic
Monoclonal Antibodies, publishing in the United Kingdom by
MacMillan Publishers Ltd., 1990).
[0081] More specifically, mRNA that encodes antibody variable (V)
region is isolated from cells such as a hybridoma that produce the
target antibody. Isolation of mRNA is carried out by preparing
total RNA according to a known method such as guanidine
centrifugation (Chirgwin, J. M. et al., Biochemistry (1979) 18,
5294-5299) or AGPC (Chomczynski, P. et al., Anal. Biochem. (1987)
162, 156-159), and the preparing mRNA using an mRNA Purification
Kit (Pharmacia) and so forth. In addition, mRNA can be prepared
directly by using the QuickPrep mRNA Purification Kit
(Pharmacia).
[0082] cDNA of the antibody V region is synthesized from the
resulting mRNA using reverse transcriptase. Synthesis of cDNA can
be carried out using, for example, the AMV Reverse Transcriptase
First-Strand cDNA Synthesis Kit. In addition, The 5'-Ampli Finder
Race Kit (Clontech) and 5'-RACE method using PCR (Frohman, M. A. et
al., Proc. Natl. Acad. Sci. USA (1988) 85, 8998-9002) can be used
to synthesize and amplify the cDNA. The target DNA fragment is
purified from the resulting PCR product and coupled with vector
DNA. Moreover, a recombinant vector is then produced from this and
inserted into E. coli and so forth followed by selecting a colony
to prepare the desired recombinant vector. The base sequence of the
target DNA is then confirmed by a known method such as the deoxy
method.
[0083] Once DNA that encodes the V region of the target antibody,
this is then coupled with DNA that encodes a desired antibody
constant region (C region) followed by incorporation into an
expression vector. Alternatively, DNA encoding the V region of the
antibody may be incorporated into an expression vector that
contains DNA of the antibody C region.
[0084] In order to produce antibody used in the present invention,
an antibody gene as will be described later is incorporated into an
expression vector that expressed under the control of, for example,
an enhancer or a promoter. Next, host cells are transformed with
this expression vector to allow expression of the antibody.
[0085] In the present invention, a gene recombinant antibody that
has been artificially altered for the purpose of lowering
interspecies antigenicity to humans can be used, examples of which
include chimeric antibody, humanized antibody and human antibody.
These altered antibodies can be produced using known methods.
[0086] Chimeric antibodies are obtained by coupling DNA encoding
antibody V region obtained in the manner described above with DNA
encoding human antibody C region followed by incorporating the
coupled product into an expression vector and producing by
inserting into a host (refer to European Unexamined Patent
Publication No. EP 125023 or International Unexamined Patent
Publication No. WO 92-19759). Chimeric antibody that is useful in
the present invention can be obtained by using this known
method.
[0087] For example, plasmids containing DNA that encode the V
regions of the L chain and H chain of chimeric PM-1 antibody have
been named pPM-k3 and pPM-h1, respectively, and Escherichia coli
retaining these plasmids have been internationally deposited based
on the Budapest Treaty under the designation NCIMB40366 and
NCIMB40362, respectively, on Feb. 12, 1991 at the National
Collections of Industrial and Marine Bacteria Limited (23 St Machar
Drive, Aberdeen AB2 1RY, Scotland, Commonwealth of Great Britain
and Northern Ireland).
[0088] Humanized antibodies, which are also referred to as reshaped
antibodies, are obtained by transplanting the complementarity
determining region (CDR) of mammals other than humans such as mice
to the complementarity determining region of human antibody, and
their typical gene recombination techniques are known (refer to
European Unexamined Patent Publication No. EP 125023 or
International Unexamined Patent Publication No. WO 92-19759).
[0089] More specifically, a DNA sequence designed so as to couple
CDR of mouse antibody with the framework (FR) region of human
antibody is synthesized by PCR from a plurality of oligonucleotides
produced so as to have overlapping portions on their ends. The
resulting DNA is then coupled with DNA that encodes human antibody
C region followed by incorporation into an expression vector and
insertion into a host to produce the DNA in that host (refer to
European Unexamined Patent Publication No. EU 239400 or
International Unexamined Patent Publication No. WO 92-19759).
[0090] An FR for which the complementarity determining region forms
a satisfactory antigen binding site is selected for the FR of the
human antibody coupled by means of CDR. The amino acids of the
framework region of the antibody variable region may be substituted
so that the complementary determining region of the reconfigured
human antibody forms a suitable antigen binding site (Sato, K. et
al., Cancer Res. (1993) 53, 851-856).
[0091] Human antibody C region is used for chimeric antibody and
humanized antibody. An example of a human antibody C region is
C.gamma., and for example, C.gamma.1, C.gamma.2, C.gamma.3 or
C.gamma.4 can be used. In addition, the human antibody C region may
be modified to improve stability of the antibody or its
production.
[0092] Chimeric antibodies are composed of a variable region of an
antibody of mammalian origin other than humans and a C region
originating in human antibody, while humanized antibodies are
composed of a complementarity determining region of an antibody of
mammalian origin other than humans and a framework region and C
region originating in human antibody, and since their antigenicity
in humans is decreased, they are useful as antibodies used in the
present invention.
[0093] A preferable specific example of a humanized antibody used
in the present invention is humanized PM-1 antibody (refer to
International Unexamined Patent Publication No. WO 92-19759).
[0094] In addition to the method previously described, another
known technology for acquiring human antibody consists of acquiring
human antibody by panning using a human antibody library. For
example, a phage that binds to an antigen can also be selected by
using a variable region of human antibody as a single chain
antibody (scfv) and expressing on the surface of a phage using the
phage display method. The DNA sequence that encodes the human
antibody variable region that binds to the antigen can then be
determined by analyzing the genes of the selected phage. Once the
DNA sequence of the scfv that binds to the antigen has been
identified, an expression vector that is equivalent to that
sequence can then be produced to acquire the human antibody. These
methods are already commonly known and reference can be made to WO
92/01047, WO 92/20791, WO 93/06213, WO 93/11236, WO 93/19172, WO
95/01438 and WO 95/15388.
[0095] Antibody gene constructed in the manner described above can
be expressed and acquired by known methods. In the case of
mammalian cells, antibody gene can be expressed with DNA or vector
that contains said DNA in which a commonly used useful promoter,
antibody gene to be expressed, and poly A signal downstream from
the 3' side are functionally bound. An example of a
promoter/enhancer is human cytomegalovirus immediately early
promoter/enhancer.
[0096] In addition, examples of other promoters/enhancers that
should used to express antibody used in the present invention
include virus promoters/enhancers such as those of retrovirus,
polyoma virus, adenovirus or Simeon virus 40 (SV40), as well as
promoters/enhancers originating in mammalian cells such as human
elongation factor 1.alpha. (HEF1.alpha.).
[0097] For example, in the case of using SV40 promoter/enhancer,
antibody can be easily expressed in accordance with the method of
Mulligan et al. (Mulligan, R. C. et al., Nature (1979) 277,
108-114) or in the case of HEF1.alpha. promoter/enhancer, antibody
can be easily expressed in accordance with the method of Mizushima
et al. (Mizushima, S. and Nagata, S., Nucleic Acids Res. (1990) 18,
5322).
[0098] In the case of Escherichia coli, antibody can be expressed
by functionally binding a commonly used useful promoter, signal
sequence for secreting antibody and antibody gene to be expressed.
Examples of promoters include lacZ promoter and araB promoter. In
the case of using lacZ promoter, antibody should be expressed in
accordance with the method of Ward et al. (Ward, E. S. et al.,
Nature (1989) 341, 544-546; Ward, E. S. et al., FASEB J. (1992) 6,
2422-2427), or in the case of using araB promoter, antibody should
be expressed in accordance with the method of Better et al.
(Better, M. et al., Science (1988) 240, 1041-1043).
[0099] The pelB signal sequence (Lei, S. P. et al., J. Bacteriol.
(1987) 169, 4379-4383) should be used for the signal sequence for
antibody secretion in the case of producing in the periplasm of E.
coli. After separating the antibody produced in the periplasm, the
antibody is used after suitably refolding the antibody structure
(refer to, for example, WO 96/30394).
[0100] Examples of replication sources that can be used include
those originating in SV40, polyoma virus, adenovirus or bovine
papilloma virus (BPV), and in order to increase the number of gene
copies in the host cell system, the expression vector can contain a
selection marker such as aminoglycoside phosphotransferase (APH)
gene, thymidine kinase (TK) gene, E. coli xanthine-guanine
phosphoribosyl transferase (Ecogpt) gene or dihydrofolate reductase
(dhfr) gene.
[0101] Any arbitrary production system can be used to produce
antibody used in the present invention. The production system for
antibody production may be an in vitro system or an in vivo system.
Examples of in vitro production systems include production systems
that use eukaryotic cells and a production systems that use
prokaryotic cells.
[0102] In the case of using eukaryotic cells, the production system
may use animal cells, plant cells or fungal cells. Known examples
of animal cells include: (1) mammalian cells such as CHO, COS,
myeloma, BHK (baby hamster kidney), HeLa and Vero cells, (2)
amphibian cells such as African tree frog follicular cells, and (3)
insect cells such as sf9, sf21 and Tn5 cells. Known examples of
plant cells include cells originating in Nicotiana tabacum, and
they should be cultured in calluses. Known examples of fungal cells
include yeasts cells such as Saccharomyces species including
Saccharomyces cerevisiae, and molds such as Aspergillus species
including Aspergillus niger.
[0103] In the case of using prokaryotic cells, a production system
that uses bacterial cells is used. Known examples of bacterial
cells include E. coli and Bacillus subtilis.
[0104] Antibody is obtained by inserting the target antibody gene
into these cells by transformation, and then culturing the
transformed cells in vitro. Culturing is carried out in accordance
with known methods. For example, DMEM, MEM, RPMI1640 or IMDM can be
used for the culture liquid, and a serum supplement such as fetal
calf serum (FCS) can also be used in combination. In addition,
antibody may also be produced in vivo by transferring cells into
which the antibody gene has been inserted to the abdominal cavity
and so forth of an animal.
[0105] On the other hand, examples of in vivo production systems
include production systems that use animals and production systems
that use plants. In the case of using an animal, examples of
production systems include those that use mammals or insects.
[0106] Examples of mammals that can be used include goats, pigs,
sheep, mice and rabbits (Vicki Glaser, SPECTRUM Biotechnology
Applications, 1993). Silkworms can be used for the insects. In the
case of using plants, tobacco plants can be used, for example.
[0107] Antibody gene is inserted into these animals or plants
followed by production and recovery of the antibody within the
bodies of the animals or plants. For example, an antibody gene is
inserted at an intermediate location in a gene that encodes a
protein uniquely produced in milk such as goat .beta. casein to
prepare in the form of a fused protein. A DNA fragment that
contains the fused protein into which the antibody gene has been
inserted is then injected into a goat embryo and this embryo is
then introduced into a female goat. The desired antibody is then
obtained from the milk produced by a transgenic goat or its progeny
that is born from the goat that has received the embryo. A suitable
hormone may be used in the transgenic goat to increase the amount
of milk containing the desired antibody produced from the
transgenic goat (Ebert, K. M. et al., Bio/Technology (1994) 12,
699-702).
[0108] In addition, in the case of using silkworms, a silkworm is
infected with baculovirus into which the target antibody gene has
been inserted followed by obtaining the desired antibody from the
silkworm body fluid (Maeda, S. et al., Nature (1985) 315, 592-594).
Moreover, in the case of using a tobacco plant, the target antibody
gene is inserted into a plant expression vector such as pMON 530,
after which this vector is inserted into bacteria such as
Agrobacterium tumefaciens. This bacteria is then used to infect a
tobacco plant such as Nicotiana tabacum to obtain the desired
antibody from the tobacco leaves (Jilian, K. -C. Ma, et al., Eur.
J. Immunol. (1994) 24, 131-138).
[0109] As has been described above, in the case of producing
antibody with an in vitro or in vivo production system, a host may
be simultaneously transfected by separately incorporating DNA
encoding antibody heavy chain (H chain) or light chain (L chain) in
separate expression vectors, or transforming a host by
incorporating DNA encoding H chain and L chain in a single
expression vector (refer to International Unexamined Patent
Publication No. WO 94-11523).
[0110] Antibody used in the present invention may be an antibody
fragment or modified product thereof provided is can be preferably
used in the present invention. Examples of antibody fragments
include Fab, F(ab')2, Fv or H chain and single chain Fv (scfv) in
which Fv or Fv or H chain and L chain are coupled with a suitable
linker.
[0111] More specifically, after forming an antibody fragment by
treating an antibody with an enzyme such as papain or pepsin, or
constructing a gene that encodes these antibody fragments and
inserting it into an expression vector, it is expressed in suitable
host cells (refer to, for example, Co, M. S. et al., J. Immunol.
(1994) 152, 2968-2976; Better, M. & Horwitz, A. H., Methods in
Enzymology (1989) 178, 476-496; Plueckthun, A. & Skerra, A.,
Methods in Enzymology (1989) 178, 476-496; Lamoyi, E., Methods in
Enzymology (1989) 121, 652-663; Rousseaux, J. et al., Methods in
Enzymology (1989) 121, 663-666; Bird, R. E. et al., TIBTECH (1991)
9, 132-137).
[0112] The aforementioned scFv is obtained by coupling antibody H
chain V region with L chain V region. In this scfv, the H chain V
region and L chain V region are coupled with a linker and
preferably a peptide linker (Huston, J. S. et al., Proc. Natl.
Acad. Sci. U.S.A. (1988) 85, 5879-5883). The H chain V region and L
chain V region in scFv may have for their origins any of the
origins described for the aforementioned antibodies. An example of
a peptide linker used to couple the V regions is an arbitrary
single chain peptide composed of 12-19 amino acid residues.
[0113] DNA that encodes scFv is obtained by using DNA that encodes
the aforementioned antibody H chain or H chain V region and DNA
that encodes L chain or L chain V region as templates, amplifying a
DNA portion that encodes a desired amino acid sequence among these
sequences by PCR using a primer pair that defines both ends, and
then amplifying by combining with a prime pair that defines the DNA
that encodes the peptide linker portion as well as both of its ends
so that each H chain and L chain is linked.
[0114] In addition, once DNA that encodes scfv is produced,
expression vectors that contain them as well as hosts that have
been transformed by said expression vectors can be obtained in
accordance with ordinary methods. In addition, scFv can be obtained
in accordance with ordinary methods by using those hosts.
[0115] These antibody fragments can be produced from a host by
acquiring and expressing their genes in the same manner as
previously described. The "antibody" referred to in the present
invention includes these antibody fragments.
[0116] Antibodies bound with various types of molecules such as
polyethylene glycol (PEG) can be used for antibody modified
products. The "antibody" referred to in the present invention
includes these antibody modified products. These antibody modified
products can be obtained by carrying out chemical modification on a
resulting antibody. These methods have already been established in
this field.
[0117] As was previously described, expressed antibody can be
separated from inside or outside cells or from a host and purified
to uniformity. Separation and purification of antibody used in the
present invention can be carried out by affinity chromatography.
Examples of columns used for affinity chromatography include a
protein A column and protein G column. Examples of carriers used
for a protein A column include Hyper D, POROS and Sepharose F.F.
Other separation and purification methods used with ordinary
proteins may also be used and there are no limitations thereon.
[0118] Antibody used in the present invention can be separated and
purified by suitably selecting and combining, for example,
chromatography other than the aforementioned affinity
chromatography, filtration, ultrafiltration, salting out or
dialysis. Examples of other types of chromatography include ion
exchange chromatography, hydrophobic chromatography and gel
filtration. These types of chromatography can be applied to
high-performance liquid chromatography (HPLC). In addition, reverse
phase HPLC may also be used.
[0119] Concentration of antibody obtained as described above can be
measured by measurement of optical absorbance, ELISA and so forth.
Namely, in the case of measuring optical absorbance, after suitably
diluting with PBS(-), optical absorbance at 280 nm is measured
followed by calculating concentration based on 1.35 OD representing
1 mg/ml. In addition, measurement of concentration by ELISA can be
carried out in the manner described below. Namely, 100 .mu.l of
goat anti-human IgG (TAG) diluted to 1 .mu.g/ml with 0.1 M
bicarbonate buffer (pH 9.6) are added to a 96-well plate (Nunc)
followed by incubating overnight at 4.degree. C. to immobilize the
antibody on the plate. After blocking, 100 .mu.l of suitably
diluted antibody used in the present invention, sample containing
antibody or human IgG standard (Cappel) are added followed by
incubating for 1 hour at room temperature.
[0120] After washing the plate, 100 .mu.l of 5000.times.-diluted
alkaline phosphatase-labeled anti-human IgG (BIOSOURCE) are added
followed by incubating for 1 hour at room temperature. After
washing the plate, substrate solution is added followed by
incubating and then measuring optical absorbance at 405 nm using a
Microplate Reader Model 3550 (BioRad) to calculate the
concentration of the target antibody.
[0121] IL-6 variant used in the present invention is a substance
that has binding activity with IL-6 receptor but does not transmit
the biological activity of IL-6. Namely, although IL-6 variant
competes with IL-6 for binding with IL-6 receptor, since it does
not transmit the biological activity of IL-6, signal transmission
by IL-6 is interrupted.
[0122] IL-6 variant is produced by introducing a mutation by
substituting an amino acid residue in the amino acid sequence of
IL-6. Although there are no limitations on the origin of the IL-6
serving as the basis of the IL-6 variant, human IL-6 is preferable
in consideration of antigenicity and so forth.
[0123] More specifically, this is carried out by predicting the
secondary structure of the amino acid sequence of IL-6 using a
known molecular modeling program such as WHATIF (Vriend, et al., J.
Mol. Graphics (1990) 8, 52-56), and then evaluating the effects on
all of the amino acid residues to be substituted. After determining
a suitable substituted amino acid residue, by then using a vector
containing a base sequence that encodes human IL-6 gene as a
template and introducing a mutation such that the amino acid is
substituted by PCR carried out in the normal manner, a gene that
encodes IL-6 variant is obtained. This can then be incorporated in
a suitable expression vector as necessary to obtain IL-6 variant in
compliance with the aforementioned recombinant antibody expression,
production and purification methods.
[0124] Specific examples of IL-6 variants are disclosed in
Brakenhoff et al., J. Biol. Chem. (1994) 269, 86-93, Savino et al.,
EMBO J. (1994) 13, 1357-1367, WO 96-18648 and WO 96-17869.
[0125] IL-6 partial peptide or IL-6 receptor partial peptide used
in the present invention is a substance that has binding activity
with IL-6 receptor or IL-6, respectively, and does not transmit the
biological activity of IL-6. Namely, IL-6 partial peptide or IL-6
receptor partial peptide specifically inhibit binding of IL-6 to
IL-6 receptor by capturing IL-6 receptor or IL-6 by binding
thereto. As a result, signal transmission by IL-6 is interrupted
since the biological activity of IL-6 is not transmitted.
[0126] IL-6 partial peptide or IL-6 receptor partial peptide is a
peptide that is composed of an amino acid sequence of a portion or
entirety of the region involved in binding between IL-6 and IL-6
receptor in the amino acid sequence of IL-6 or IL-6 receptor. Such
a peptide is normally composed of 10 to 80, preferably 20 to 50 and
more preferably 20 to 40 amino acid residues.
[0127] IL-6 partial peptide of IL-6 receptor partial peptide can be
produced by a method in which the region involved in binding
between IL-6 and IL-6 receptor is identified in the amino acid
sequence of IL-6 or IL-6 receptor, and a portion or all of that
amino acid sequence is normally known, examples of which include
genetic engineering techniques and peptide synthesis methods.
[0128] IL-6 partial peptide or IL-6 receptor partial peptide can be
produced using genetic engineering techniques by incorporating DNA
that encodes a desired peptide in an expression vector and
obtaining the desired peptide in compliance with the aforementioned
recombinant antibody expression, production and purification
methods.
[0129] IL-6 partial peptide or IL-6 receptor partial peptide can be
produced using peptide synthesis methods by using a method normally
used in peptide synthesis, such as a solid phase synthesis method
or liquid phase synthesis method.
[0130] More specifically, this should be carried out according to
the method described in Zokuiyakuhin-no-Kaihatsu, Vol. 14, Peptide
Synthesis, N. Yajima, ed., Hirokawa Shoten Publishing (1991). In
the case of solid phase synthesis, a method is used in which, for
example, a peptide chain is elongated by alternately repeating a
reaction in which an amino acid corresponding to the C terminal of
the peptide to be synthesized is bound to a support that is
insoluble in organic solvent, and amino acids in which the
.alpha.-amino groups and side chain functional groups are protected
with suitable protecting groups are sequentially bound in order
from the C terminal to the N terminal, and a reaction in which said
protecting groups of .alpha.-amino groups of amino acids or peptide
bound to the resin are eliminated. Solid phase peptide synthesis
methods are broadly divided into the Boc method and Fmoc method
depending on the type of protecting groups used.
[0131] After synthesizing the target peptide in this manner, a
de-protecting reaction and reaction for severing the peptide chain
from the support are carried out. In the reaction for severing the
peptide chain, hydrogen fluoride or trifluoromethane sulfonic acid
are normally used in the Boc method, while TFA is normally used in
the Fmoc method. In the Boc method, for example, the aforementioned
protected peptide resin is treated in hydrogen fluoride in the
presence of anisole. Next, the protecting groups are eliminated and
the peptide is severed from the support followed by recovery of the
peptide. A crude peptide is then obtained by freeze-drying the
product. On the other hand, in the Fmoc method, for example, a
de-protecting reaction and reaction for severing the peptide chain
from the support can be carried out using the same procedure as
described above in TFA.
[0132] The resulting crude peptide can be separated and purified by
applying to HPLC. Elution should be carried out under the optimum
conditions using a water-acetonitrile-based solvent normally used
for purification of protein. The fraction corresponding to the peak
of the resulting chromatography profile is then separated and
freeze-dried. The peptide fraction purified in this manner is then
identified by molecular weight analysis using mass spectrometry,
amino acid composition analysis or amino acid sequence
analysis.
[0133] Specific examples of IL-6 partial peptides and IL-6 receptor
partial peptides are disclosed in Japanese Unexamined Patent
Publication No. 2-188600, Japanese Unexamined Patent Publication
No. 7-324097, Japanese Unexamined Patent Publication No. 8-311098
and U.S. Pat. No. 5,210,075.
[0134] IL-6 signal transmission inhibitory activity of IL-6
antagonist used in the present invention can be evaluated by
normally used methods. More specifically, IL-6-dependent human
myeloma line (S6B45, KPMM2), human Lennert's T lymphoma cell line
KT3 or IL-6-dependent cell line MH60 or BSF2 is cultured followed
by the addition of IL-6 while simultaneously in the presence of
IL-6 antagonist and measurement of the uptake of .sup.3H-thymidine
by IL-6-dependent cells.
[0135] In addition, .sup.125I-labeled IL-6 bound to IL-6 receptor
expressing cells is measured by culturing IL-6 receptor expressing
cells in the form of U266 cells followed by the addition of
.sup.125I-labeled IL-6 and the simultaneous addition of IL-6
antagonist. In the aforementioned assay system, a negative control
group that does not contain IL-6 antagonist is provided in addition
to the group in which IL-6 antagonist is present, and comparison of
the results obtained from the two groups makes it possible to
evaluate the IL-6 inhibitory activity of the IL-6 antagonist.
[0136] As will be indicated in the examples to be described later,
since growth inhibitory effects on mesothelioma cells have been
observed for anti-IL-6 receptor antibody, anti-IL-6 receptor
antibody and other IL-6 antagonists were suggested as being useful
as therapeutic agents for mesothelioma.
[0137] The treatment target in the present invention is a mammal.
The mammal of the treatment target is preferably a human.
[0138] The mesothelioma therapeutic agent or mesothelioma cell
growth inhibitor of the present invention can be administered
systemically or locally either orally or parenterally. For example,
intravenous infusion or other form of intravenous injection,
intramuscular injection, intrathoracic injection, intraperitoneal
injection, subcutaneous injection, suppositories, enema or oral
enteric-coated pills and so forth can be selected, and the
administration method can be suitably selected according to the age
and symptoms of the patient. The effective dose is selected within
the range of 0.01 mg to 100 mg per kilogram of body weight per
administration. Alternatively, a dose of 1 to 1000 mg, and
preferably 5 to 50 mg, can be selected per patient.
[0139] The preferable dose and administration method in the case of
anti-IL-6 receptor antibody, for example, is such that the amount
of free antibody present in the blood is the effective dose, a
specific example of which is a method by which it is administered
using a method such as intravenous drip or other form of
intravenous injection or subcutaneous injection and so forth
according to an administration schedule such as twice a week, once
a week, once every two weeks or once every four weeks in a single
administration or divided among several administrations at a dose
of 0.5 mg to 40 mg, and preferably 1 mg to 20 mg, per month (4
weeks) per 1 kilogram of body weight. The administration schedule
can be adjusted such as by lengthening the administration interval
from twice per week or once per week to once every two weeks, once
every three weeks or once every four weeks while observing the
patient's condition and trends in blood test values.
[0140] The mesothelioma therapeutic agent or mesothelioma cell
growth inhibitor of the present invention may contain a
pharmaceutically acceptable carrier or additive depending on the
administration route. Examples of such carriers and additives
include water, pharmaceutically acceptable organic solvents,
collagen, polyvinyl alcohol, polyvinyl pyrrolidone, carboxyvinyl
polymer, sodium carboxymethyl cellulose, sodium polyacrylate,
sodium arginate, water-soluble dextran, sodium carboxymethyl
starch, pectin, methyl cellulose, ethyl cellulose, xanthan gum, gum
Arabic, casein, gelatin, agar, diglycerin, propylene glycol,
polyethylene glycol, Vaseline, paraffin, stearyl alcohol, stearic
acid, human serum albumin (HSA), mannitol, sorbitol, lactose and
surfactants acceptable for use as pharmaceutical additives.
Although additives used are selected are suitably selected or
combined from the aforementioned additives according to the drug
form, they are not limited to those indicated above.
EXAMPLES
[0141] Although the following provides a detailed explanation of
the present invention through its examples and reference examples,
the present invention is not limited thereto.
Example 1
Production of IL-6 by Malignant Mesothelioma Cell Lines
[0142] Culturing of malignant mesothelioma cell lines MSTO, H2052,
H28, H226 and H2452 was started at a cell concentration of
5.times.10.sup.4/well in a 24-well plate containing culture liquid
(RPMI containing 10% fetal calf serum (FCS)), the cell culture
liquid was replaced on the following day, after which the cells
were cultured for additional 3 days followed by measuring the
concentrations of IL-6 in the culture supernatant using a fully
automated chemiluminescent enzyme immunoassay system (Fujirebio,
Lumipulse) and correcting for the amount of cellular protein. Those
results are shown in FIG. 1. The experiment was repeated three
times. Although cell line H28 did not produce IL-6, the other four
lines produced IL-6. Cell lines H2052 and H226 produced
particularly high levels of IL-6.
Example 2
Expression of IL-6R in Malignant Mesothelioma Cell Lines
[0143] The expression levels of IL-6 receptor were measured for
five malignant mesothelioma cell lines at the mRNA level. KT-3
cells were used for the positive control, and synoviocytes were
used for the negative control. These cells were cultured for 48
hours in RPMI containing 10% FCS, and mRNA that encodes IL-6
receptor IL-6R) in the cells was measured by reverse-transcribed
PCR (RTPCR) using the GeneAmp PCR System (Applied Biosystems) for
the detection device. Those results are shown in FIG. 2. FIG. 2
(bottom) indicates the amount of mRNA of the GAPDH
(glyceraldehyde-3-phosphate dehydrogenase) used for the internal
control.
[0144] According to these results, malignant mesothelioma cells are
believed to express hardly any IL-6 receptor. Since the pleural
fluid in cases of malignant pleural mesothelioma consists of bloody
pleural fluid, soluble IL-6 receptor is surmised to be present in
large amounts, and this is believed to be involved in transmission
of IL-6 irritation.
Example 3
Induction of VEGF Production by IL-6 Stimulation (1)
[0145] Tumor cells of malignant mesothelioma cell lines H2052 and
H2452 were cultured in three series in 24-well plates at an initial
cell concentration of 5.times.10.sup.4/well in RPMI1640 medium. On
the following day, the cell culture liquid was replaced followed by
commencement of stimulation by (1) recombinant IL-6 (10 ng/ml), (2)
recombinant IL-6 (10 ng/ml)+recombinant soluble IL-6R (100 ng/ml),
and (3) inhibition by the anti-IL-6 receptor antibody, humanized
PM-1 antibody (refer to WO 92/19759) (25 .mu.g/ml) (RPMI was used
for the medium control). After culturing for an additional 3 days,
the concentrations of vascular endothelial growth factor (VEGF) in
the culture supernatants were measured using the Quantikine Human
VEGF Immunoassay Kit (R & D Systems) and corrected for the
amount of cellular protein.
[0146] Those results are shown in FIG. 3. As is clear from these
graphs, production of VEGF was inducted by IL-6 stimulation in both
cell lines H2052 and H2452.
Example 4
Induction of VEGF Production by IL-6 Stimulation (2)
[0147] The experiment of Example 3 was repeated using malignant
mesothelioma cell line H28. Those results are shown in FIG. 4. As
is clear from these results, although cell line H28 produces high
levels of VEGF, it did not respond to stimulation by IL-6.
Example 5
Phosphorylation of STAT3 by IL-6 Stimulation
[0148] Cell line H2025, in which production of VEGF is induced by
IL-6, and cell line H28, in which production of VEGF is not induced
by IL-6, were incubated in the presence of recombinant IL-6 (10
ng/ml) and soluble recombinant IL-6 receptor (100 ng/ml) together
with signal transducer and activator of transcription 3 (STAT3)
followed by analysis of the phosphorylation from STAT3 to p-STAT3
in hour 0, hour 0.5 and hour 1 of incubation by Western blotting.
Those results are shown in FIG. 5.
[0149] As is clear from FIG. 5, prominent phosphorylation of STAT3
was observed for cell line H2052 at 30 minutes after IL-6
stimulation. In contrast, only slight phosphorylation of STAT3 was
observed in response to IL-6 stimulation for cell line H28.
Furthermore, p-STAT3 in FIG. 5 indicates phosphorylated STAT3,
while STAT3 indicates the sum of phosphorylated and
non-phosphorylated STAT3.
Example 6
Induction of SOCS3 by IL-6 Stimulation
[0150] Cell line H2025, in which production of VEGF is induced by
IL-6, and cell line H28, in which production of VEGF is not induced
by IL-6, were stimulated by incubating in the presence of
recombinant IL-6 (10 ng/ml) and soluble recombinant IL-6 receptor
(100 ng/ml) followed by measuring the expression levels of induced
suppressor of cytokine signaling 3 (SOCS3) and
glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by measuring the
levels of mRNA that encode them following RT-PCR amplification in
hour 0, hour 2 and hour 4 of incubation. Those results are shown in
FIG. 6.
[0151] As is clear from FIG. 6, induction of SOCS3 mRNA was
observed 2 hours after IL-6 stimulation in cell line H2052.
Continuously high expression of SOCS3 was observed in cell line
H28.
Example 7
VEGF Promoter Assay
[0152] A plasmid pGL3-VEGF, which controls the expression of
luciferase gene by VEGF promoter, and a plasmid pGL3-VEGFmut, which
controls the expression of luciferase gene by a mutated VEGF
promoter, were produced (FIG. 7).
[0153] 50,000H2052 cells each were transfected with 1 .mu.g of
pGL3-VEGF or pGL3-VEGFmut, and the transfected cells were
stimulated with recombinant IL-6 (10 ng/ml) and recombinant soluble
IL-6 receptor (100 ng/ml). After stimulating for 2 days, the
luciferase activity induced from the VEGF promoter and mutated VEGF
promoter was examined. Those results are shown in FIG. 8.
[0154] As is clear from FIG. 8, in the case of having removed the
phosphorylated STAT3 binding site from the VEGF promoter,
activation of the VEGF promoter due to IL-6 stimulation was no
longer observed. Based on the results of the aforementioned
Examples 5, 6 and 7, increased production of VEGF due to IL-6
stimulation in cell line H2052 was believed to be mediated by a
JAK-STAT system. This predicted system is shown in FIG. 9.
Example 8
Growth Promotion of H2052 and H226 by Addition of IL-6 and Soluble
IL-6 Receptor
[0155] Cell line H2052 cells were disseminated in a 96-well plate
containing RPMI medium containing 10% FCS at 500 cells/well
followed by culturing in five series for 6 to 7 days in the
presence or absence of recombinant soluble IL-6 receptor at 100
ng/ml and in the presence of various concentrations (0, 1, 10 or
100 ng/ml) of IL-6. Those results are shown in FIG. 10 and FIG. 13.
As is clear from these graphs, cell line H2052 and cell line H226
grow IL-6 concentration-dependently in the presence of recombinant
soluble IL-6 receptor (100 ng/ml).
Example 9
Inhibition of Growth Promotion of H2052 Cells due to Addition of
IL-6 and IL-6R by Antibody to IL-6R (Anti-IL-6R Antibody)
[0156] In order to determine whether or not growth promotion of
H2052 cells by IL-6 and IL-6 receptor is inhibited by anti-IL-6R
antibody, H2052 cells were disseminated in a 96-well plate
containing RPMI medium containing 10% FCS at 500 cells/well
followed by culturing in three series for 7 days in the presence of
recombinant soluble IL-6 at 10 ng/ml and recombinant soluble IL-6
receptor at 100 ng/ml and in the presence of various concentrations
(0.1 or 25 .mu.g/ml) of humanized PM-1 antibody. Following
culturing, the amount of growth of H2052 cells (OD 450) was
measured by MTS assay. Those results are shown in FIG. 11. As a
result, anti-IL-6 antibody was determined to inhibit growth
concentration-dependently. On the other hand, inhibitory effects
were not observed in the case of adding human IgG1 instead of MRA
at the same concentration as a control.
Example 10
Growth Promotion of H226 Cells by Addition of IL-6 and Soluble IL-6
Receptor and Inhibition by Anti-IL-6R Antibody
[0157] Cell line H226 cells were disseminated in a 96-well plate
containing RPMI medium containing 10% FCS at a concentration of 500
cells/well followed by culturing in three series for 7 days in the
presence of recombinant soluble IL-6 receptor at 100 ng/ml and in
the presence of various concentrations (0, 1, 10 or 100 ng/ml) of
IL-6. Those results are shown in FIG. 12. As is clear from the
graph, H226 cells that produce high levels of IL-6 grew IL-6
concentration-dependently in the presence of recombinant soluble
IL-6 receptor (100 ng/ml) while their growth was inhibited by
anti-IL-6R antibody in the same manner as H2052 cells producing
high levels of IL-6.
Example 11
Inhibition of Growth Promotion of Cell Line H2052 and Cell Line
H226 Induced by Addition of IL-6 and Soluble IL-6 Receptor by
Anti-IL-6 Receptor Antibody
[0158] Cells of cell line H2052 and cell line H225 were
disseminated in a 96-well plate at 200 cells/well in RPMI medium
containing 10% FCS followed by culturing in five series for 6 days
in the presence of IL-6 (10 ng/ml) and soluble IL-6 receptor (100
ng/ml) and in the presence of various concentrations (0, 1
.mu.g/ml, 5 .mu.g/ml) of humanized PM-1 antibody. After culturing,
the cell growth rates of cell line H2052 and cell line H226 were
measured by MTS assay. The cell growth rates indicated how many
times cell growth increased as compared with the absence of
addition of IL-6/sIL-6R. Those results are shown in FIG. 14. As a
result, anti-IL-6 receptor antibody completely inhibited the growth
promoting action induced by addition of IL-6/sIL-6R in cell line
H2052 and cell line H226. On the other hand, growth inhibitory
effects were not observed in the case of adding the same
concentrations of human IgG1 (Sigma) as a control instead of
anti-IL-6 receptor antibody.
Example 12
Inhibition of Induction of VEGF Production Induced by IL-6
Stimulation by Anti-IL-6 Receptor Antibody
[0159] A study was made of inhibition of the induction of VEGF
production induced by IL-6 stimulation in malignant mesothelioma
cell lines MSTO, H226, H2052 and H2452 by anti-IL-6 receptor
antibody under the same conditions as Example 3 with the exception
of the concentrations of the humanized PM-1 antibody (0.1 .mu.g/ml,
5 .mu.g/ml). Those results are shown in FIG. 15. As a result,
anti-IL-6 receptor antibody completely inhibited induction of VEGF
production induced by IL-6/sIL-6R stimulation. On the other hand,
inhibitory action on induction of VEGF production was not observed
in the case of adding the same concentrations of human IgG1 (Sigma)
as a control instead of anti-IL-6 receptor antibody.
Example 13
Inhibition of STAT3 Phosphorylation by Anti-IL-6 Receptor
Antibody
[0160] A study was made to determine whether STAT3 phosphorylation
induced by stimulation by IL-6 (10 ng/ml) and soluble IL-6 receptor
(100 ng/ml) is inhibited by 5 .mu.g/ml of anti-IL-6 receptor
antibody in cell line H2052 and cell line H2452 that produce VEGF.
Those results are shown in FIG. 16. As a result, anti-IL-6 receptor
antibody significantly inhibited phosphorylated STAT3 (p-STAT3)
induced by IL-6/sIL-6R stimulation in malignant mesothelioma cells.
On the other hand, significant inhibition of the phosphorylation of
STAT3 was not observed in the case of adding the same concentration
of human IgG1 (Sigma) as a control instead of anti-IL-6 receptor
antibody.
Example 14
Effect of Anti-VEGF Antibody on Growth of Malignant Mesothelioma
Cells
[0161] Cells of cell line H2052 and cell line H226 were
disseminated in a 96-well plate at 500 cells/plate in RPMI medium
containing 10% FCS, followed by culturing in five series for 6-7
days in the presence of IL-6 (10 ng/ml) and recombinant soluble
IL-6 receptor (100 ng/ml) and in the presence of 1 .mu.g/ml of
anti-VEGF antibody. After culturing, the amounts of growth were
examined by MTS assay. The same concentration of human IgG1 (Sigma)
was used for the control instead of anti-VEGF antibody. Those
results are shown in FIG. 17. As a result, anti-VEGF antibody did
not inhibit cell growth induced by IL-6/sIL-6R stimulation. On the
basis of this result, growth action on malignant mesothelioma cells
induced by IL-6/sIL-6R stimulation was clearly determined to not be
mediated by VEGF.
Reference Example 1
Preparation of Human Soluble IL-6 Receptor
[0162] Soluble IL-6 receptor was produced by PCR using a plasmid
pBSF2R.236 that contains DNA encoding IL-6 receptor obtained
according to the method of Yamasaki, et al. (Yamasaki, K. et al.,
Science (1988) 241, 825-828). Plasmid pBSF2R.236 was then digested
with restrictase SphI to obtain IL-6 receptor cDNA which was then
inserted into mp18 (Amersham). A mutation was introduced into the
IL-6 receptor cDNA by PCR with the In Vitro Mutagenesis System
(Amersham) using a synthetic oligoprimer designed so as to insert a
stop codon into the IL-6 receptor cDNA. As a result of this
procedure, a stop codon was inserted at the location of amino acid
345, and cDNA was obtained that encodes soluble IL-6 receptor.
[0163] In order to express the cDNA encoding soluble IL-6 receptor
in CHO cells, it was coupled with plasmid pSV (Pharmacia) to obtain
plasmid pSVL344. Soluble IL-6 receptor cDNA severed with
HindIII-SalI was then inserted into plasmid pECEdhfr containing
dhfr cDNA to obtain CHO cell expression plasmid pECEdhfr344.
[0164] 10 .mu.g of plasmid pECEdhfr344 were then used to transfect
dhfr-CHO cell line DXB-11 (Urlaub, G. et al., Proc. Natl. Acad.
Sci. USA (1980) 77, 4216-4220) according to the calcium phosphate
precipitation method (Chen, C. et al., Mol. Cell. Biol. (1987) 7,
2745-2751). The transfected CHO cells were then cultured for 3
weeks in nucleoside-free .beta.MEM selective culture liquid
containing 1 mM glutamine, 10% dialyzed FCS, 100 U/ml of penicillin
and 100 .mu.g/ml of streptomycin.
[0165] The selected CHO cells were then screened by a limiting
dilution method to obtain a single CHO cell clone. This CHO cell
clone was amplified with methotrexate at a concentration from 20 nM
to 200 nM to obtain human soluble IL-6 receptor-producing CHO cell
line 5E27. CHO cell line 5E27 was cultured in Iscove's Modified
Dulbecco's Medium (IMDM, Gibco) containing 5% FBS. After recovering
the culture supernatant, the concentration of soluble IL-6 receptor
in the culture supernatant was measured by ELISA. As a result,
soluble IL-6 receptor was confirmed to be present in the culture
supernatant.
Reference Example 2
Preparation of Anti-Human IL-6 Antibody
[0166] A BALB/c mouse was immunized with 10 .mu.g of recombinant
IL-6 (Hirano, T. et al., Immunol. Lett. (1988) 17, 41) together
with Freund's complete adjuvant, and this was continued once a week
until anti-IL-6 antibody was able to be detected in the serum.
Immunocytes were excised from local lymph nodes and fused with
myeloma cell line P3U1 using polyethylene glycol 1500. A hybridoma
was selected according to the method of Oi, et al. using HAT
culture liquid (Selective Methods in Cellular Immunology, W. H.
Freeman and Co., San Francisco, 351, 1980) to establish a hybridoma
that produced anti-human IL-6 antibody.
[0167] An IL-6 binding assay was performed in the manner described
below on the hybridoma that produced anti-human IL-6 antibody.
Namely, a flexible polyvinyl 96-well microplate (Dynatech
Laboratories, Alexandria, Va.) was coated overnight at 4.degree. C.
with 100 .mu.l of goat anti-mouse Ig (10 .mu.g/ml, Cooper
Biomedical, Malvern, Pa.) in 0.1 M carbonate-hydrogen carbonate
buffer (pH 9.6). Next, the plate was treated for 2 hours at room
temperature with 100 .mu.l of PBS containing 1% bovine serum
albumin (BSA).
[0168] After washing the plate with PBS, 100 .mu.l of hybridoma
culture supernatant were added to each well followed by incubating
overnight at 4.degree. C. The plate was washed and
.sup.125I-labeled recombinant IL-6 was added to each well at 2000
cpm/0.5 ng/well followed by measuring the radioactivity of each
well after washing using a gamma counter (Beckman Gamma 9000,
Beckman Instruments, Fullerton, Calif.). 32 of 216 hybridoma clones
were positive according to the IL-6 binding assay. Stable
MH166.BSF2 was ultimately obtained from these clones. The anti-IL-6
antibody MH166 produced by said hybridoma had IgG1.kappa.
subtype.
[0169] Next, neutralizing activity on hybridoma growth by MH166
antibody was investigated using IL-6-dependent mouse hybridoma
clone MH60.BSF2. MH60.BSF2 cells were divided among the wells of a
microplate at 1.times.10.sup.4/200 .mu.l/well followed by the
addition of sample containing MH166 antibody and culturing for 48
hours, and then additionally culturing for 6 hours after adding
.sup.3H-thymidine (New England Nuclear, Boston, Mass.) at 0.5
.mu.Ci/well. The cells were then placed on glass filter paper and
treated with an automatic harvester (Labo Mash Science, Tokyo,
Japan). Rabbit anti-IL-6 antibody was used for the control.
[0170] As a result, MH166 antibody volume-dependently inhibited
uptake of .sup.3H-thymidine by MH60.BSF2 cells induced by IL-6.
Thus, MH166 antibody was clearly demonstrated to neutralize IL-6
activity.
Reference Example 3
Preparation of Anti-Human IL-6 Receptor Antibody
[0171] Anti-IL-6 receptor antibody MT18 produced according to the
method of Hirata, et al. (Hirata, Y. et al., J. Immunol. (1989)
143, 2900-2906) was bound to activated Sepharose 4B (Pharmacia Fine
Chemicals, Piscataway, N.J.) according to attached protocol to
purify IL-6 receptor (Yamasaki, K. et al., Science (1988) 241,
825-828). Human myeloma cell line U266 was solubilized with
p-paraaminophenyl methane sulfonyl fluoride hydrochloride (Wako
Chemicals) containing 1% digitonin (Wako Chemicals), 10 mM
triethanol amine (pH 7.8) and 0.15 M NaCl (digitonin buffer), and
then mixed with MT18 antibody bound to Sepharose 4B beads.
Subsequently, the beads were washed six times with digitonin buffer
to obtain partially purified IL-6 receptor for immunization.
[0172] A BALB/c mouse was immunized four times every 10 days with
the aforementioned partially purified IL-6 receptor obtained from
3.times.10.sup.9 U266 cells followed by production of hybridoma in
accordance with ordinary methods. The binding activity of hybridoma
culture supernatant from positive growth wells to IL-6 receptor was
investigated according to the method described below.
5.times.10.sup.7 U266 cells were labeled with .sup.35S-methionine
(2.5 mCi) and solubilized with the aforementioned digitonin buffer.
The solubilized U266 cells were then mixed with MT18 antibody bound
to Sepharose 4B beads having a volume of 0.04 ml followed by
washing six times with digitonin buffer, eluting the
.sup.35S-methionine-labeled IL-6 receptor with 0.25 ml of digitonin
buffer (pH 3.4) and neutralizing with 0.025 ml of 1 M Tris (pH
7.4).
[0173] 0.05 ml of hybridoma culture supernatant were mixed with
0.01 ml of Protein G Sepharose (Pharmacia). After washing, the
Sepharose was incubated with 0.005 ml of
.sup.35S-methionine-labeled IL-6 receptor solution prepared as
described above. The immunoprecipitate was then analyzed with
SDS-PAGE and hybridoma culture supernatant that reacts with IL-6
receptor was investigated. As a result, reaction-positive hybridoma
clone PM-1 (FERM BP-2998) was established. Antibody produced from
hybridoma PM-1 have the IgG1.kappa. subtype.
[0174] The IL-6 binding inhibitory activity of antibody produced by
hybridoma PM-1 on human IL-6 receptor was investigated using human
myeloma cell line U266. Human recombinant IL-6 was prepared from E.
coli (Hirano, T. et al., Immunol. Lett. (1988) 17, 41-45) and
labeled with .sup.125I using Bolton-Hunter reagent (New England
Nuclear, Boston, Mass.) (Taga, T. et al., J. Exp. Med. (1987) 166,
967-981).
[0175] 4.times.10.sup.5 U266 cells were cultured with 70% (v/v)
hybridoma PM-1 culture supernatant and 14000 cpm of
.sup.125I-labeled IL-6 for 1 hour. 70 .mu.l of sample were layered
onto 300 .mu.l of FCS in a 400 .mu.l microfuge polyethylene tube
followed by centrifugation and measurement of radioactivity of the
cells.
[0176] As a result, antibody produced by hybridoma PM-1 was clearly
determined to inhibit binding of IL-6 to IL-6 receptor.
Reference Example 4
Preparation of Anti-Mouse IL-6 Receptor Antibody
[0177] Monoclonal antibody to mouse IL-6 receptor was prepared
according to the method described in Saito, T. et al., J. Immunol.
(1991) 147, 168-173.
[0178] CHO cells producing mouse soluble IL-6 receptor were
cultured in IMDM culture liquid containing 10% FCS followed by
purification of mouse soluble IL-6 receptor from the culture
supernatant using an affinity column in which anti-mouse IL-6
receptor antibody RS12 (refer to the aforementioned Saito, T. et
al.) was immobilized in Affigel 10 gel (BioRad).
[0179] 50 .mu.g of the resulting mouse soluble IL-6 receptor were
mixed with Freund's complete adjuvant and injected into the abdomen
of a Wistar rat. The rat was additionally immunized with Freund's
incomplete adjuvant starting two weeks later. Rat spleen cells were
then harvested on day 45, and after fusing 2.times.10.sup.8 cells
with 1.times.10.sup.7 cells of mouse myeloma cell line P3U1 using
50% PEG1500 (Boehringer-Mannheim) in accordance with ordinary
methods, the fused cells were screened for hybridoma with HAT
medium.
[0180] After adding hybridoma culture supernatant to a plate coated
with rabbit anti-rat IgG antibody (Cappel), the mouse soluble IL-6
receptor was allowed to react. Next, hybridoma that produced
antibody to mouse soluble IL-6 receptor was screened by ELISA using
rabbit anti-mouse IL-6 receptor antibody alkaline
phosphatase-labeled sheep anti-rabbit IgG. The hybridoma clones
that were confirmed to produce antibody were sub-screened twice to
obtain a single hybridoma clone. That clone was named MR16-1.
[0181] The neutralizing activity during information transmission by
mouse IL-6 of this hybridoma-producing antibody was investigated
according to the uptake of .sup.3H-thymidine using MH60.BSF2 cells
(Matsuda, T. et al., J. Immunol. (1988) 18, 951-956).
1.times.10.sup.4 cells/200 .mu.l/well of MH60.BSF2 cells were
prepared in a 96-well plate. 10 pg/ml of mouse IL-6 and 12.3 to
1000 ng/ml of MR16-1 antibody or RS12 antibody were added to this
plate and cultured for 44 hours at 37.degree. C. and 5% CO.sub.2
followed by the addition of 1 .mu.Ci/well of .sup.3H-thymidine. The
uptake of 3H-thymidine was then measured 4 hours later. As a
result, MR16-1 antibody inhibited the uptake of .sup.3H-thymidine
by MH60.BSF2 cells.
[0182] Thus, antibody produced by hybridoma MR16-1 (FERM BP-5875)
was clearly determined to inhibit binding of IL-6 to IL-6
receptor.
* * * * *