U.S. patent application number 16/739890 was filed with the patent office on 2020-11-05 for viral vectors and their use in therapeutic methods.
The applicant listed for this patent is Catherex, Inc., The General Hospital Corporation, Georgetown University. Invention is credited to Paul Johnson, Robert L. Martuza, Samuel D. Rabkin, Tomoki Todo.
Application Number | 20200345835 16/739890 |
Document ID | / |
Family ID | 1000004957368 |
Filed Date | 2020-11-05 |
United States Patent
Application |
20200345835 |
Kind Code |
A1 |
Johnson; Paul ; et
al. |
November 5, 2020 |
VIRAL VECTORS AND THEIR USE IN THERAPEUTIC METHODS
Abstract
The invention provides viral vectors (e.g., herpes viral
vectors) and methods of using these vectors to treat disease.
Inventors: |
Johnson; Paul; (Vancouver,
CA) ; Martuza; Robert L.; (Cambridge, MA) ;
Rabkin; Samuel D.; (Swampscott, MA) ; Todo;
Tomoki; (Belmont, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The General Hospital Corporation
Georgetown University
Catherex, Inc. |
Boston
Washington
Dover |
MA
DC
DE |
US
US
US |
|
|
Family ID: |
1000004957368 |
Appl. No.: |
16/739890 |
Filed: |
January 10, 2020 |
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15383578 |
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10532095 |
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16739890 |
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14524163 |
Oct 27, 2014 |
9555072 |
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13924936 |
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8871193 |
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14524163 |
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12721599 |
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8470577 |
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13924936 |
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7749745 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C12N 2710/16643
20130101; C12N 2710/16632 20130101; A61K 35/768 20130101; A61K
39/245 20130101; C12N 7/00 20130101; A61K 2039/5256 20130101; A61K
35/763 20130101; C12N 2710/16662 20130101; C12N 15/86 20130101;
C12N 2710/16671 20130101; C12N 2710/16634 20130101; A61K 2039/585
20130101; A61K 38/162 20130101; A61K 2039/5254 20130101; A61K 48/00
20130101; A61K 2039/53 20130101 |
International
Class: |
A61K 39/245 20060101
A61K039/245; C12N 15/86 20060101 C12N015/86; A61K 35/763 20060101
A61K035/763; A61K 35/768 20060101 A61K035/768; A61K 38/16 20060101
A61K038/16; C12N 7/00 20060101 C12N007/00 |
Claims
1.-5. (canceled)
6. A method of treating metastatic cancer in a patient, said method
comprising administering to said patient having metastatic cancer a
herpes simplex virus (HSV-1) comprising an inactivating mutation in
the ICP47 locus of said herpes virus that results in early
expression of US11, and an inactivating mutation in the .gamma.34.5
neurovirulence locus of said virus.
7. The method of claim 6, wherein said HSV-1 is administered to a
tumor of said patient.
8. (canceled)
9. The method of claim 6, wherein said inactivating mutation in the
ICP47 locus of said HSV-1 is in the BstEII-Eco NI fragment of the
BamHI.times.fragment of said virus.
10. (canceled)
11. The method of claim 6, wherein said herpes virus further
comprises an inactivating mutation in the ICP6 locus of said herpes
virus.
12.-23. (canceled)
24. The method of claim 6, wherein the HSV-1 further comprises
sequences encoding a heterologous gene product.
25. The method of claim 24, wherein said heterologous gene product
comprises a vaccine antigen or an immunomodulatory protein.
26.-30. (canceled)
31. the method of claim 6, wherein said early expression of US11 is
a result of the US11 gene being under control of an
early-expression promoter.
32. The method of claim 6, wherein said early-expressing promoter
is the ICP47 promoter of said virus.
33. The method of claim 25, wherein said immunomodulatory protein
is selected from the group consisting of a cytokine, a chemokine,
RANTES, a macrophage inflammatory peptide, a complement component
or receptor, an immune system accessory molecules, an adhesion
molecule, and an adhesion receptor molecule.
34. The method of claim 33, wherein said cytokine is selected from
the group consisting of an interleukin, tumor necrosis factor,
granulocyte macrophage colony stimulating factor (GM-CSF),
macrophage colony stimulating factor (M-CSF), and granulocyte
colony stimulating factor (G-CSF).
Description
FIELD OF THE INVENTION
[0001] This invention relates to viruses and their use in
therapeutic methods.
BACKGROUND OF THE INVENTION
[0002] The use of replication-competent viral vectors, such as
herpes simplex virus type 1 (HSV-1) vectors, is an attractive
strategy for tumor therapy, because such viruses can replicate and
spread in situ, exhibiting oncolytic activity through direct
cytopathic effect (Kirn, J. Clin. Invest. 105:837-839, 2000). A
number of oncolytic HSV-1 vectors have been developed that have
mutations in genes associated with neurovirulence and/or viral DNA
synthesis, in order to restrict replication of these vectors to
transformed cells and not cause disease (Martuza, J. Clin. Invest.
105:841-846, 2000).
[0003] In designing viral vectors for clinical use, it is essential
that ample safeguards be employed. G207 is an oncolytic HSV-1
vector derived from wild-type HSV-1 strain F (Mineta et al., Nat.
Med. 1:938-943, 1995). It has deletions in both copies of the major
determinant of HSV neurovirulence, the .gamma.34.5 gene, and an
inactivating insertion of the E. coli lacZ gene in UL39, which
encodes the infected-cell protein 6 (ICP6) (Mineta et al., Nat.
Med. 1:938-943, 1995). ICP6 is the large subunit of ribonucleotide
reductase, a key enzyme for nucleotide metabolism and viral DNA
synthesis in non-dividing cells but not dividing cells (Goldstein
et al., J. Virol. 62:196-205, 1988). In addition to being the major
determinant of HSV neurovirulence (Chou et al., Science
250:1262-1266, 1990), ICP34.5 also functions by blocking host cell
induced shutoff of protein synthesis in response to viral infection
(Chou et al., Proc. Natl. Acad. Sci. U.S.A. 89:3266-3270, 1992).
This is likely responsible for the less efficient growth of
.gamma.34.5.sup.- mutants compared to wild-type HSV, which has been
observed in many tumor cell types (McKie et al., Br. J. Cancer
74:745-752, 1996; Andreansky et al., Cancer Res. 57:1502-1509,
1997; Chambers et al., Proc. Natl. Acad. Sci. U.S.A. 92:1411-1415,
1995). This double mutation confers important advantages: minimal
chance of reverting to wild type, preferential replication in tumor
cells, attenuated neurovirulence, and ganciclovir/acyclovir
hypersensitivity. G207 effectively kills multiple types of tumor
cells in culture and in mice harboring tumors subcutaneously or
intracranially (Mineta et al., Nat. Med. 1:938-943, 1995; Yazaki et
al., Cancer Res. 55:4752-4756, 1995; Toda et al., Hum. Gene Ther.
9:2177-2185, 1998; Todo et al., Hum. Gene Ther. 10:2741-2755, 1999;
Chahlavi et al., Neoplasia 1:162-169, 1999; Kooby et al., FASEB J.
13:1325-1334, 1999; Lee et al., J. Gastrointest. Surg. 3:127-133,
1999). In several syngeneic tumor models in immunocompetent mice,
oncolysis caused by intraneoplastic inoculation of G207 elicited a
systemic immune response and tumor-specific cytotoxic T lymphocytes
(Todo et al., Hum. Gene Ther. 10:2741-2755, 1999; Toda et al., Hum.
Gene Ther. 10:385-393, 1999; Todo et al., Hum. Gene Ther.
10:2869-2878, 1999).
[0004] G207 has minimal toxicity when injected into the brains of
HSV-1-susceptible mice or nonhuman primates (Hunter et al., J.
Virol. 73:6319-6326, 1999; Sundaresan et al., J. Virol.
74:3832-3841, 2000; Todo et al., Mol. Ther. 2:588-595, 2000).
Recently, G207 has been examined in patients with recurrent
malignant glioma (Markert et al., Gene Ther. 7:867-874, 2000), and
the results from this phase I clinical trial indicate that
intracerebral inoculation of G207 is safe at doses of up to
3.times.10.sup.9 plaque forming units (pfu), the highest dose
tested. While the use of oncolytic viruses is a promising approach
for cancer therapy, the therapeutic benefits will likely depend on
the dose and route of administration, the extent of intratumoral
viral replication, and the host immune response.
[0005] HSV-1 infection causes down-regulation of major
histocompatibility complex (MHC) class I expression on the surface
of infected host cells (Jennings et al., J. Virol. 56:757-766,
1985; Hill et al., J. Immunol. 152:2736-2741, 1994). The binding of
ICP47 to the transporter associated with antigen presentation (TAP)
blocks antigenic peptide transport in the endoplasmic reticulum and
loading of MHC class I molecules (York et al., Cell 77:525-535,
1994; Hill et al., Nature 375:411-415, 1995; Fruh et al., Nature
375:415-418, 1995). The binding of ICP47 is species-specific for
TAPs from large mammals (Jugovic et al., J. Virol. 72:5076-5084,
1998), with the affinity for murine TAP about 100-fold less than
for human (Ahn et al., EMBO J. 15:3247-3255, 1996).
SUMMARY OF THE INVENTION
[0006] The invention provides herpes simplex viruses (e.g., HSV-1
viruses) that include mutations within the BstEII-EcoNI fragment of
the BamHI.times.fragment of the viruses. These viruses can also
include, for example, an inactivating mutation in the .gamma.34.5
neurovirulence locus of the viruses, and/or an inactivating
mutation in the ICP6 locus of the viruses.
[0007] Also included in the invention are herpes simplex viruses
(e.g., an HSV-1 virus) that include an inactivating mutation in the
ICP47 locus of the viruses, in the absence of an inactivating
mutation in the .gamma.34.5 neurovirulence locuses of the virus.
Optionally, these viruses also can include an inactivating mutation
in the ICP6 locus of the viruses.
[0008] The invention also provides methods of inducing a systemic
immune response to cancer in a patient, which involve administering
to the patient a herpes virus that includes an inactivating
mutation in the ICP47 locus of the herpes virus. The herpes virus
can be administered, for example, to a tumor of the patient. In
addition, the patient can have or be at risk of developing
metastatic cancer, and the treatment can be carried out to treat or
prevent such cancer. The inactivating mutation in the ICP47 locus
of the herpes virus can be, for example, in the BstEII-EcoNI
fragment of the BamHI.times.fragment of the virus. Optionally, the
virus can include an inactivating mutation in the .gamma.34.5
neurovirulence locus of the herpes virus, and/or an inactivating
mutation in the ICP6 locus of the herpes virus.
[0009] The invention also provides herpes viruses that include a
first mutation that inactivates the .gamma.34.5 neurovirulence
locus of the viruses and a second mutation that results in early
expression of US11, in the absence of an ICP47-inactivating
mutation in the BamHI.times.fragment of the viruses. Early
expression of US11 can be achieved, for example, by inserting a
promoter upstream from the US11 gene, or by inserting a US11 gene
under the control of an early-expressing promoter into the genome
of the virus. The viruses can also include a mutation that results
in downregulation of ICP47 expression, in the absence of a mutation
in the BamHI.times.fragment of the virus. The downregulation of
ICP47 can be due to, for example, a deletion in, or inactivation
of, the ICP47 promoter, or the fusion of ICP47 with a peptide that
prevents functional expression of ICP47.
[0010] The invention also includes a herpes virus that includes a
first mutation that inactivates the .gamma.34.5 neurovirulence
locus of the virus and a second mutation that results in
downregulation of ICP47 expression, in the absence of a mutation in
the BamHI.times.fragment of the virus. The downregulation of ICP47
can be due to, for example, a deletion in, or inactivation of, the
ICP47 promoter, or the fusion of ICP47 with a peptide that prevents
functional expression of ICP47.
[0011] The viruses described above can also include an additional
mutation (e.g., a mutation in the ICP6 locus) to prevent reversion
to wild type. The viruses can also include, optionally, sequences
encoding a heterologous gene product, such as a vaccine antigen or
an immunomodulatory protein. The viruses described herein can be
herpes simplex viruses (HSV), such as herpes simplex-1 viruses
(HSV-1).
[0012] The invention further provides pharmaceutical compositions
that include any of the viruses described herein and a
pharmaceutically acceptable carrier, adjuvant, or diluent, as well
as methods of treating cancer in a patient, involving administering
such a pharmaceutical composition to the patient. Also included in
the invention are methods of immunizing a patient against an
infectious disease, cancer, or an autoimmune disease, involving
administering such a pharmaceutical composition to the patient.
[0013] The invention provides several advantages. For example, the
viruses of the invention replicate in, and thus destroy, dividing
cells, such as cancer cells, while not affecting other cells in the
body. An additional advantage of the viruses of the invention in
which ICP47 is deleted is that the immune response induced by such
viruses is enhanced, which results in a better antitumor immune
response. The viruses of the invention also include multiple
mutations, eliminating the possibility of reversion to wild type.
Moreover, although the viruses of the invention may have enhanced
replication, this is not accompanied by increased toxicity. In
addition, replication of herpes simplex viruses can be controlled
through the action of antiviral drugs, such acyclovir, which block
viral replication. These features render the viruses of the
invention to be not only effective, but safe as well.
[0014] Other features and advantages of the invention will be
apparent from the following detailed description, drawings, and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIGS. 1A-1E are schematic representations of the HSV-1
genome and approaches to making vectors included in the invention.
FIG. 1A is a schematic representation of the HSV-1 genome. FIG. 1B
is an expanded map of the ICP47 locus, showing the locations of the
overlapping 3' co-terminal transcripts for US10, US11, and US12
(ICP47). FIG. 1C is a schematic representation of plasmid pIE12,
which contains an 1818 basepair BamHI-EcoRI fragment from the HSV-1
BamHI.times.fragment, which encompasses the ICP47 region (Johnson
et al., J. Virology 68(10):6347-6362, 1994). This plasmid can be
used to introduce modifications into the ICP47 locus of the viral
genome, as is described further below. FIG. 1D is a schematic
representation of plasmid pIE12 .DELTA., which was derived from
pIE12 by deleting 312 basepairs between the indicated BstEII and
NruI sites. This plasmid was used to generate the .gamma.34.5
suppressor mutants R47.DELTA. and G47.DELTA.. FIG. 1E is a
schematic representation of the details of the 3' terminus of the
ICP47 coding region. Sequences can be inserted into the indicated
BstEII site, without disrupting sequences between the BstEII and
NruI sites, for the purposes of changing the temporal regulation of
the late US11 gene, to generate a .gamma.34.5 suppressor function,
and/or preventing functional expression of the ICP47 gene
product.
[0016] FIGS. 2A-2C are schematic representations of the structure
of G47.DELTA.. FIG. 2A is a schematic of the HSV-1 genome showing
the regions modified in G47.DELTA.. The HSV-1 genome consists of
long and short unique regions (U.sub.L and U.sub.S), each bounded
by terminal (T) and internal (I) repeat regions (R.sub.L and
R.sub.S). The parental virus G207 was engineered from wild-type
HSV-1 strain F by deleting 1 kilobase within both copies of the
.gamma.34.5 gene, and inserting the E. coli lacZ gene into the ICP6
coding region. G47.DELTA. was derived from G207 by deleting 312
basepairs from the ICP47 locus, as indicated. FIG. 2B is a map of
the ICP47 locus, showing locations of the overlapping 3'
co-terminal transcripts (US10, US11, and ICP47), open reading
frames (thick arrow), and ICP47 splice junctions ({circumflex over
( )}). FIG. 2C is a map of plasmid pIE12.DELTA., which was used to
generate deletions by homologous recombination with the indicated
flanking sequences. While US11 is regulated as a true late gene in
wild-type HSV-1, deletion between the indicated BstEII and EcoNI
sites places US11 under control of the ICP47 immediate-early
promoter. Restriction site abbreviations are: B, BamHI; Bs, BstEII;
E, EcoRI; EN, EcoNI; Nr, NruI.
[0017] FIG. 3 is a graph showing virus yields of
replication-competent HSV-1 mutants in various cell lines. Cells
were seeded on 6 well plates at 5.times.10.sup.5 cells/well.
Triplicate wells were infected with R3616, R47.DELTA., G207,
G47.DELTA., or strain F at a MOI of 0.01. At 24 hours
post-infection, cells were scraped into the medium and progeny
virus was titered on Vero cells. In all cell lines tested,
G47.DELTA. showed a significantly higher replication capability
than G207. Results represent the mean of triplicates.+-.SD.
[0018] FIG. 4 is a series of graphs showing the cytopathic effect
of G47.DELTA. in vitro. Cells were plated into 6 well plates at
2.times.10.sup.5 cells/well. After 24 hours of incubation, cells
were infected with G207 or G47.DELTA. at a MOI of 0.01 or 0.1, or
without virus (Control). The number of surviving cells was counted
daily and expressed as a percentage of mock-infected controls.
G47.DELTA. exhibited a significantly stronger cytopathic effect
than G207 in all three human tumor cell lines (U87MG and melanomas
624 and 888) at a MOI of 0.01, and also in Neuro2a murine
neuroblastoma cells at a MOI of 0.1. The results are the mean of
triplicates.+-.SD. * p<0.05, ** p<0.01, *** p<0.001, G207
versus G47.DELTA., unpaired t test.
[0019] FIGS. 5A-5C are a series of graphs showing that G4F7.DELTA.
precludes down-regulation of MHC class I expression in infected
host cells. FIG. 5A is a graph of flow cytometric analyses of MHC
class I expression in Detroit 551 human fibroblast cells 48 hours
after infection with HSV-1 (MOI=3). While all HSVs with an intact
.alpha.47 gene (wild-type strain F and G207) significantly
down-regulated MHC class I expression, G47.DELTA. completely
precluded the down-regulation. FIG. 5B is a graph showing a time
course of MHC class I down-regulation in Detroit 551 cells infected
with HSV-1. For each virus, the peak value of MHC class I
expression at 6, 24, or 48 hours post-infection, analyzed by flow
cytometry, was expressed as a percentage of the peak value of
mock-infected cells (control) at each time point. MHC class I
down-regulation by G207 and R3616 occurred in a time-dependent
fashion. Dissociation of MHC class I expression between
.alpha.47-deleted mutants (G47.DELTA. and R47.DELTA.) and
.alpha.47-intact viruses became apparent at 24-48 hours
post-infection. FIG. 5C is a series of graphs showing flow
cytometric analyses of MHC class I expression in human melanoma
cell lines 24 hours after infection with G207 and G47.DELTA..
G47.DELTA. caused a partial preclusion of MHC class I
down-regulation in melanomas 1102 and 938, resulting in greater MHC
class I expression than G207.
[0020] FIG. 6 is a series of graphs showing that
G47.DELTA.-infected tumor cells stimulate T cells to a greater
extent than G207-infected tumor cells. Human melanoma cells were
infected with mock (no virus), G207, or G47.DELTA. at a MOI of 3,
and after 3-6 hours, co-cultured with an equal number of responding
human T cells for 18 hours. T cell stimulation was assessed by an
increase in IFN-.gamma. release into conditioned media.
G47.DELTA.-infected melanoma 1102 cells caused a significantly
greater stimulation of TIL888 cells compared with G207-infected
1102 cells (p<0.01, unpaired t test). G47.DELTA.-infected 938
melanoma cells also stimulated TIL1413 cells, although the
improvement was not statistically significant compared with
G207-infected 938 cells (p=0.1, unpaired t test). Neither G207 nor
G47.DELTA.-infected melanoma 888 cells caused a significant
stimulation of TIL888 cells.
[0021] FIG. 7 is a set of graphs showing that G47.DELTA. exhibits
greater antitumor efficacy than G207 in vivo. Subcutaneous tumors
of U87MG human glioma (Left) or Neuro2a murine neuroblastoma
(Right) were generated in 6-week-old female athymic mice or
6-week-old female A/J mice, respectively. Established tumors of
approximately 6 mm in diameter were inoculated with G207 or
G47.DELTA. (1.times.10.sup.6 pfu), or mock (PBS with 10% glycerol)
on days 0 and 3. G47.DELTA. treatment was significantly more
efficacious than G207 in both tumor models, resulting in smaller
average tumor volumes (p<0.05 for U87MG on day 24 and p<0.001
for Neuro2a on day 15, G207 versus G47.DELTA., unpaired t
test).
DETAILED DESCRIPTION
[0022] The invention provides viruses that can be used in
therapeutic methods, such as, for example, in the treatment of
cancer. These viruses are particularly well suited for this
purpose, as they replicate in, and thus destroy, dividing cells
(e.g., cancer cells), but they do not replicate substantially, and
thus are avirulent, in non-dividing cells. The viruses of the
invention can also be used in immunization methods, for the
treatment or prevention of, for example, infectious diseases,
cancer, or autoimmune diseases. An advantageous feature of many of
the viruses of the invention is that, in addition to directly
causing lysis of tumor cells, they induce a systemic immune
response against tumors. Thus, these viruses can be used not only
to treat a given tumor, to which they may be directly administered,
but also to prevent or treat cancer metastasis.
[0023] Several of the viruses of the invention are herpes simplex
viruses (HSV) that include an inactivating mutation in the ICP47
locus of the virus. This mutation can occur, for example, between
the BstEII site and the EcoNI site of the BamHI.times.fragment of
HSV-1, and may comprise, e.g., deletion of the BstEll-ExoNI
fragment. Optionally, a herpes simplex virus including a mutation
between the BstEII and EcoNI sites can also include additional
mutations. For example, such a virus can include an inactivating
mutation in the .gamma.34.5 neurovirulence determination locus of
the virus, and/or an inactivating mutation elsewhere in the genome,
e.g., in the ICP6 locus. The invention also includes herpes simplex
viruses that include inactivating mutations in the ICP47 locus, in
the absence of an inactivating mutation in the .gamma.34.5
neurovirulence locus. Optionally, such a virus can include an
inactivating mutation in another, non-.gamma.34.5 neurovirulence
locus, e.g., in the ICP6 locus.
[0024] The invention includes additional viruses that are based on
herpes viruses, such as herpes simplex (HSV viruses), for example,
HSV-1 (e.g., HSV-1 strain F or strain Patton) or HSV-2, that
include an inactivating mutation in a virulence gene. In the case
of herpes simplex viruses, this mutation can be an inactivating
mutation in the .gamma.34.5 gene, which is the major HSV
neurovirulence determinant. (See, e.g., FIG. 1 for details
concerning the construction of examples of viruses that are
included in the invention.)
[0025] In addition to the .gamma.34.5 mutation, in one example, the
viruses of the invention can include a modification that results in
early expression of US11, in the absence of an ICP-47-inactivating
mutation in the BamHI.times.fragment of the vector. US11 is
normally expressed as a true-late gene, requiring DNA replication
for its expression. However, early expression of US11 in some of
the viruses of the invention can compensate for the .gamma.34.5
defect by preventing the PKR-mediated shut-off of protein synthesis
(see, e.g., FIG. 1E). Early expression of US11 in such a virus can
be achieved by, for example, inserting an early-acting promoter
upstream of the US11 gene (FIG. 1E). Such promoters can include,
for example, the human cytomegalovirus (CMV) IE promoter, an HSV-1
IE promoter, an HSV-1 E promoter, or any other heterologous
promoter that is active before the onset of DNA replication in the
HSV-1 genome (see, e.g., below). An alternative approach to
achieving early expression of US11 included in the invention
involves inserting an exogenous copy of a US11 gene elsewhere in
the viral genome, under the control of any suitable promoter that
is active early in infection, such as one of those listed above,
for example.
[0026] An additional HSV-based virus included in the invention
includes, in addition to an inactivating mutation in the
.gamma.34.5 locus, a second modification that results in
downregulation of ICP47 expression, in the absence of a mutation in
the BamHI.times.fragment of the virus. In one example of such a
virus, ICP47 coding sequences are fused with sequences that encode
a peptide that prevents functional expression of ICP47 (see, e.g.,
FIG. 1E). Such a peptide can include, for example, a PEST sequence,
which is rich in proline (P), glutamate (E), serine (S), and
threonine (T), and thus provides intramolecular signals for rapid
proteolytic degradation (Rechsteiner et al., Trends Biochem. Sci.
21(7):267-271, 1996). Such a poison sequence can be inserted into
the virus at, for example, the BstEII site, upstream of a strong
promoter driving US11 (FIG. 1E). In an alternative vector, signals
that direct RNA degradation are incorporated into the virus, to
direct degradation of ICP47 RNA.
[0027] Other viruses included in the invention can include, in
addition to an inactivating mutation in the .gamma.34.5 locus, two
additional modifications. The first additional modification results
in early expression of US11 and the second modification results in
downregulation of ICP47 expression, as described above, in the
absence of a mutation in the BamHI.times.fragment of the virus. In
one example of such a virus, an early-expressing promoter is
inserted upstream of the US11 gene and ICP47 coding sequences are
fused with sequences encoding a poison sequence, such as a PEST
sequence (FIG. 1E).
[0028] Any of the viruses described above and herein and elsewhere
can include an additional mutation or modification that is made to
prevent reversion of the virus to wild type. For example, the virus
can include a mutation in the ICP6 gene (see below), which encodes
the large subunit of ribonucleotide reductase. A specific example
of a virus that is included in the invention, G47.DELTA., is
described in further detail below. Briefly, this virus includes a
deletion in the .gamma.34.5 gene, an inactivating insertion in the
ICP6 gene, and a 312 basepair deletion in the ICP47 gene.
[0029] The viruses described herein can be generated from any
herpes virus family member, such as a neurotrophic,
B-lymphotrophic, or T-lymphotrophic herpes virus. For example, a
herpes simplex virus (HSV), such as HSV-1 or HSV-2, can be used.
Alternatively, any of the following viruses can be used:
Varicella-zoster virus (VZV), herpes virus 6 (HSV-6), Epstein Barr
virus, cytomegalovirus, HHV6, and HHV7. The methods and viruses
described herein are described primarily in reference to HSV-1, but
these methods can readily be applied to any of these other viruses
by one of skill in this art.
[0030] As is noted above, the viruses of the invention can be used
to treat cancer, as these viruses replicate in, and thus destroy
dividing cells, such as cancer cells, but are avirulent to other
cells. Examples of cancer cells that can be destroyed, according to
the invention, include cancer cells of nervous-system type tumors,
for example, astrocytoma, oligodendroglioma, meningioma,
neurofibroma, glioblastoma, ependymoma, Schwannoma,
neurofibrosarcoma, neuroblastoma, pituitary tumor (e.g., pituitary
adenoma), and medulloblastoma cells. Other types of tumor cells
that can be killed, pursuant to the present invention, include, for
example, melanoma, prostate carcinoma, renal cell carcinoma,
pancreatic cancer, breast cancer, lung cancer, colon cancer,
gastric cancer, fibrosarcoma, squamous cell carcinoma,
neurectodermal, thyroid tumor, lymphoma, hepatoma, mesothelioma,
and epidermoid carcinoma cells, as well as other cancer cells
mentioned herein. Also as is noted above, the viruses of the
invention, which induce a systemic immune response to cancer, can
be used to prevent or to treat cancer metastasis.
[0031] Other therapeutic applications in which killing of a target
cell is desirable include, for example, ablation of keratinocytes
and epithelial cells responsible for warts, ablation of cells in
hyperactive organs (e.g., thyroid), ablation of fat cells in obese
patients, ablation of benign tumors (e.g., benign tumors of the
thyroid or benign prostatic hypertrophy), ablation of growth
hormone-producing adenohypophyseal cells to treat acromegaly,
ablation of mammotropes to stop the production of prolactin,
ablation of ACTH-producing cells to treat Cushing's disease,
ablation of epinephrine-producing chromaffin cells of the adrenal
medulla to treat pheochromocytoma, and ablation of
insulin-producing beta islet cells to treat insulinoma. The viruses
of the invention can be used in these applications as well.
[0032] The effects of the viruses of the invention can be augmented
if the viruses also contain a heterologous nucleic acid sequence
encoding one or more therapeutic products, for example, a
cytotoxin, an immunomodulatory protein (i.e., a protein that either
enhances or suppresses a host immune response to an antigen), a
tumor antigen, an antisense RNA molecule, or a ribozyme. Examples
of immunomodulatory proteins include, e.g., cytokines (e.g.,
interleukins, for example, any of interleukins 1-15, .alpha.,
.beta., or .gamma.-interferons, tumor necrosis factor, granulocyte
macrophage colony stimulating factor (GM-CSF), macrophage colony
stimulating factor (M-CSF), and granulocyte colony stimulating
factor (G-CSF)), chemokines (e.g., neutrophil activating protein
(NAP), macrophage chemoattractant and activating factor (MCAF),
RANTES, and macrophage inflammatory peptides MIP-la and MIP-1b),
complement components and their receptors, immune system accessory
molecules (e.g., B7.1 and B7.2), adhesion molecules (e.g., ICAM-1,
2, and 3), and adhesion receptor molecules. Examples of tumor
antigens that can be produced using the present methods include,
e.g., the E6 and E7 antigens of human papillomavirus, EBV-derived
proteins (Van der Bruggen et al., Science 254:1643-1647, 1991),
mucins (Livingston et al., Curr. Opin. Immun. 4(5):624-629, 1992),
such as MUC1 (Burchell et al., Int. J. Cancer 44:691-696, 1989),
melanoma tyrosinase, and MZ2-E (Van der Bruggen et al., supra).
(Also see WO 94/16716 for a further description of modification of
viruses to include genes encoding tumor antigens or cytokines.)
[0033] As is noted above, the therapeutic product can also be an
RNA molecule, such as an antisense RNA molecule that, by
hybridization interactions, can be used to block expression of a
cellular or pathogen mRNA. Alternatively, the RNA molecule can be a
ribozyme (e.g., a hammerhead or a hairpin-based ribozyme) designed
either to repair a defective cellular RNA, or to destroy an
undesired cellular or pathogen-encoded RNA (see, e.g., Sullenger,
Chem. Biol. 2(5):249-253, 1995; Czubayko et al., Gene Ther.
4(9):943-949, 1997; Rossi, Ciba Found. Symp. 209:195-204, 1997;
James et al., Blood 91(2):371-382, 1998; Sullenger, Cytokines Mol.
Ther. 2(3):201-205, 1996; Hampel, Prog. Nucleic Acid Res. Mol. Bio.
58:1-39, 1998; Curcio et al., Pharmacol. Ther. 74(3):317-332,
1997).
[0034] A heterologous nucleic acid sequence can be inserted into a
virus of the invention in a location that renders it under the
control of a regulatory sequence of the virus. Alternatively, the
heterologous nucleic acid sequence can be inserted as part of an
expression cassette that includes regulatory elements, such as
promoters or enhancers. Appropriate regulatory elements can be
selected by those of ordinary skill in the art based on, for
example, the desired tissue-specificity and level of expression.
For example, a cell-type specific or tumor-specific promoter can be
used to limit expression of a gene product to a specific cell type.
This is particularly useful, for example, when a cytotoxic,
immunomodulatory, or tumor antigenic gene product is being produced
in a tumor cell in order to facilitate its destruction. In addition
to using tissue-specific promoters, local administration of the
viruses of the invention can result in localized expression and
effect.
[0035] Examples of non-tissue specific promoters that can be used
in the invention include the early Cytomegalovirus (CMV) promoter
(U.S. Pat. No. 4,168,062) and the Rous Sarcoma Virus promoter
(Norton et al., Molec. Cell. Biol. 5:281, 1985). Also, HSV
promoters, such as HSV-1 IE and IE 4/5 promoters, can be used.
[0036] Examples of tissue-specific promoters that can be used in
the invention include, for example, the prostate-specific antigen
(PSA) promoter, which is specific for cells of the prostate; the
desmin promoter, which is specific for muscle cells (Li et al.,
Gene 78:243, 1989; Li et al., J. Biol. Chem. 266:6562, 1991; Li et
al., J. Biol. Chem. 268:10403, 1993); the enolase promoter, which
is specific for neurons (Forss-Petter et al., J. Neuroscience Res.
16(1):141-156, 1986); the .beta.-globin promoter, which is specific
for erythroid cells (Townes et al., EMBO J. 4:1715,1985); the
tau-globin promoter, which is also specific for erythroid cells
(Brinster et al., Nature 283:499, 1980); the growth hormone
promoter, which is specific for pituitary cells (Behringer et al.,
Genes Dev. 2:453, 1988); the insulin promoter, which is specific
for pancreatic .gamma. cells (Selden et al., Nature 321:545, 1986);
the glial fibrillary acidic protein promoter, which is specific for
astrocytes (Brenner et al., J. Neurosci. 14:1030, 1994); the
tyrosine hydroxylase promoter, which is specific for
catecholaminergic neurons (Kim et al., J. Biol. Chem. 268:15689,
1993); the amyloid precursor protein promoter, which is specific
for neurons (Salbaum et al., EMBO J. 7:2807, 1988); the dopamine
.gamma.-hydroxylase promoter, which is specific for noradrenergic
and adrenergic neurons (Hoyle et al., J. Neurosci. 14:2455, 1994);
the tryptophan hydroxylase promoter, which is specific for
serotonin/pineal gland cells (Boularand et al., J. Biol. Chem.
270:3757, 1995); the choline acetyltransferase promoter, which is
specific for cholinergic neurons (Hersh et al., J. Neurochem.
61:306, 1993); the aromatic L-amino acid decarboxylase (AADC)
promoter, which is specific for catecholaminergic/5-HT/D-type cells
(Thai et al., Mol. Brain Res. 17:227, 1993); the proenkephalin
promoter, which is specific for neuronal/spermatogenic epididymal
cells (Borsook et al., Mol. Endocrinol. 6:1502, 1992); the reg
(pancreatic stone protein) promoter, which is specific for colon
and rectal tumors, and pancreas and kidney cells (Watanabe et al.,
J. Biol. Chem. 265:7432, 1990); and the parathyroid hormone-related
peptide (PTHrP) promoter, which is specific for liver and cecum
tumors, and neurilemoma, kidney, pancreas, and adrenal cells
(Campos et al., Mol. Rnfovtinol. 6:1642, 1992).
[0037] Examples of promoters that function specifically in tumor
cells include the stromelysin 3 promoter, which is specific for
breast cancer cells (Basset et al., Nature 348:699, 1990); the
surfactant protein A promoter, which is specific for non-small cell
lung cancer cells (Smith et al., Hum. Gene Ther. 5:29-35, 1994);
the secretory leukoprotease inhibitor (SLPI) promoter, which is
specific for SLPI-expressing carcinomas (Garver et al., Gene Ther.
1:46-50, 1994); the tyrosinase promoter, which is specific for
melanoma cells (Vile et al., Gene Therapy 1:307, 1994; WO 94/16557;
WO 93/GB1730); the stress inducible grp78/BiP promoter, which is
specific for fibrosarcoma/tumorigenic cells (Gazit et al., Cancer
Res. 55(8):1660, 1995); the AP2 adipose enhancer, which is specific
for adipocytes (Graves, J. Cell. Biochem. 49:219, 1992); the
.alpha.-1 antitrypsin transthyretin promoter, which is specific for
hepatocytes (Grayson et al., Science 239:786, 1988); the
interleukin-10 promoter, which is specific for glioblastoma
multiform cells (Nitta et al., Brain Res. 649:122, 1994); the
c-erbB-2 promoter, which is specific for pancreatic, breast,
gastric, ovarian, and non-small cell lung cells (Harris et al.,
Gene Ther. 1:170, 1994); the .alpha.-B-crystallin/heat shock
protein 27 promoter, which is specific for brain tumor cells
(Aoyama et al., Int. J. Cancer 55:760, 1993); the basic fibroblast
growth factor promoter, which is specific for glioma and meningioma
cells (Shibata et al., Growth Fact. 4:277, 1991); the epidermal
growth factor receptor promoter, which is specific for squamous
cell carcinoma, glioma, and breast tumor cells (Ishii et al., Proc.
Natl. Acad. Sci. U.S.A. 90:282, 1993); the mucin-like glycoprotein
(DF3, MUC1) promoter, which is specific for breast carcinoma cells
(Abe et al., Proc. Natl. Acad. Sci. U.S.A. 90:282, 1993); the mtsl
promoter, which is specific for metastatic tumors (Tulchinsky et
al., Proc. Natl. Acad. Sci. U.S.A. 89:9146, 1992); the NSE
promoter, which is specific for small-cell lung cancer cells
(Forss-Petter et al., Neuron 5:187, 1990); the somatostatin
receptor promoter, which is specific for small cell lung cancer
cells (Bombardieri et al., Eur. J. Cancer 31A:184, 1995; Koh et
al., Int. J. Cancer 60:843, 1995); the c-erbB-3 and c-erbB-2
promoters, which are specific for breast cancer cells (Quin et al.,
Histopathology 25:247, 1994); the c-erbB4 promoter, which is
specific for breast and gastric cancer cells (Rajkumar et al.,
Breast Cancer Res. Trends 29:3, 1994); the thyroglobulin promoter,
which is specific for thyroid carcinoma cells (Mariotti et al., J.
Clin. Endocrinol. Meth. 80:468, 1995); the .alpha.-fetoprotein
promoter, which is specific for hepatoma cells (Zuibel et al., J.
Cell. Phys. 162:36, 1995); the villin promoter, which is specific
for gastric cancer cells (Osborn et al., Virchows Arch. A. Pathol.
Anat. Histopathol. 413:303, 1988); and the albumin promoter, which
is specific for hepatoma cells (Huber, Proc. Natl. Acad. Sci.
U.S.A. 88:8099, 1991).
[0038] As is noted above, the viruses of the invention can be used
in in vivo methods, for example, to kill a cell and/or to introduce
a therapeutic gene product into the cell. To carry out these
methods, the viruses of the invention can be administered by any
conventional route used in medicine. For example, a virus of the
invention can be administered directly into a tissue in which an
effect, e.g., cell killing and/or therapeutic gene expression, is
desired, for example, by direct injection or by surgical methods
(e.g., stereotactic injection into a brain tumor; Pellegrino et
al., Methods in Psychobiology (Academic Press, New York, New York,
67-90, 1971)). An additional method that can be used to administer
vectors into the brain is the convection method described by Bobo
et al. (Proc. Natl. Acad. Sci. U.S.A. 91:2076-2080, 1994) and
Morrison et al. (Am. J. Physiol. 266:292-305, 1994). In the case of
tumor treatment, as an alternative to direct tumor injection,
surgery can be carried out to remove the tumor, and the vectors of
the invention inoculated into the resected tumor bed to ensure
destruction of any remaining tumor cells. Alternatively, the
vectors can be administered via a parenteral route, e.g., by an
intravenous, intraarterial, intracerebroventricular, subcutaneous,
intraperitoneal, intradermal, intraepidermal, or intramuscular
route, or via a mucosal surface, e.g., an ocular, intranasal,
pulmonary, oral, intestinal, rectal, vaginal, or urinary tract
surface.
[0039] Any of a number of well-known formulations for introducing
viruses into cells in mammals, such as humans, can be used in the
invention. (See, e.g., Remington's Pharmaceutical Sciences
(18.sup.th edition), ed. A. Gennaro, 1990, Mack Publishing Co.,
Easton, Pa.) However, the viruses can be simply diluted in a
physiologically acceptable solution, such as sterile saline or
sterile buffered saline, with or without an adjuvant or
carrier.
[0040] The amount of virus to be administered depends, e.g., on the
specific goal to be achieved, the strength of any promoter used in
the virus, the condition of the mammal (e.g., human) intended for
administration (e.g., the weight, age, and general health of the
mammal), the mode of administration, and the type of formulation.
In general, a therapeutically or prophylactically effective dose
of, e.g., from about 10.sup.1 to 10.sup.10 plaque forming units
(pfu), for example, from about 5.times.10.sup.4 to
1.times.10.sup.6pfu, e.g., from about 1.times.10.sup.5 to about
4.times.10.sup.5 pfu, although the most effective ranges may vary
from host to host, as can readily be determined by one of skill in
this art. Also, the administration can be achieved in a single dose
or repeated at intervals, as determined to be appropriate by those
of skill in this art.
[0041] A specific example of a virus of the invention, designated
G47.DELTA., which is a new, multimutated, replication-competent
HSV-1 virus, derived from G207 by a deletion within the
non-essential .alpha.47 gene (Mavromara-Nazos et al., J. Virol.
60:807-812, 1986), is now described. Because of the overlapping
transcripts encoding ICP47 and US11 (FIG. 2B), the deletion in a47
also places the late US11 gene under control of the immediate-early
a47 promoter. This enhances the growth properties of
.gamma.34.5.sup.- mutants by precluding the shutoff of protein
synthesis (Mohr et al., EMBO J. 15:4759-4766, 1996; He et al., J.
Virol. 71:6049-6054, 1997; Cassady et al., J. Virol. 72:7005-7011,
1998; Cassady et al., J. Virol. 72:8620-8626, 1998). Nevertheless,
we found that G47.DELTA. was as safe as G207, which is now in
clinical trials in humans, when inoculated into the brains of A/J
mice at 2.times.10.sup.6 pfu. We show here that human melanoma
cells infected with G47.DELTA. were more effective at stimulating
their matched tumor-infiltrating lymphocytes (TILs) than those
infected with G207, that G47.DELTA. showed enhanced replication in
cultured tumor cells, and that G47.DELTA. was more efficacious than
G207 at inhibiting tumor growth in both human xenograft and mouse
syngeneic tumor models tested. Our results show that G47.DELTA. can
be used for tumor therapy. Additional details of this virus and its
properties are provided as follows.
Experimental Results
Construction and Replication of G47.DELTA.
[0042] G47.DELTA. was constructed by deleting 312 basepairs from
G207 in the U.sub.S region adjacent to TR.sub.S (FIG. 2). Southern
blot analyses of G47.DELTA. DNA confirmed the presence of a 0.3
kilobase deletion in the .alpha.47 gene and a 1 kilobase deletion
in the .gamma.34.5 gene. R47.DELTA., with the same deletion in the
.alpha.47 locus, was generated from R3616, the parental virus of
G207 that has an active ribonucleotide reductase (Chou et al.,
Science 250:1262-1266, 1990).
[0043] To investigate the effects of the a47 deletion on the growth
properties of .gamma.34.5-deficient mutants (G207 and R3616), we
determined the yield of progeny virus following infection of human
tumor cells lines SK-N-SH (neuroblastoma), U87MG (glioma), U373MG
(glioma), and SQ20B (head and neck squamous cell carcinoma). By 24
hours post-infection at a low MOI, G47.DELTA. produced higher
yields than G207, resulting in an approximately 4 to 1000-fold
increase in titer (FIG. 3). In a single-step growth experiment in
U87MG cells (MOI=2), the virus yield of G47.DELTA. was 12 times
greater than with G207. R47.DELTA. similarly yielded higher titers
than its parent R3616 in all tumor cell lines tested; however,
neither G47.DELTA. nor R47.DELTA. grew as well as wild-type
parental strain F. To determine whether virus yields were affected
by cell density, Vero and SK-H-SH cells were seeded at normal or
high density (8.times.10.sup.5 or 1.6.times.10.sup.6 cells/well),
infected with strain F, G207, or G47.DELTA. at a MOI of 0.01, and
harvested 48 hours post-infection. G47.DELTA. produced a higher
yield in the high-density culture, as opposed to G207, which had a
reduced yield. The ability to generate higher yields of G47.DELTA.
in Vero cells facilitates manufacturing of high titer stocks for
clinical use.
Cytopathic Effect of G47.DELTA. In Vitro
[0044] The cytolytic activity of G47.DELTA. in vitro was compared
to that of G207 in various neural crest-derived tumor cell lines.
In human cell lines, U87MG and melanomas 624 and 888, G47.DELTA.
killed tumor cells significantly more rapidly than G207 at a low
MOI of 0.01 (FIG. 4). At a MOI of 0.1, both G207 and G47.DELTA.
killed all the cells within 1-3 days of infection. Neuro2a, a
murine neuroblastoma cell line, was resistant to killing by both
G207 10 and G47.DELTA. at a MOI of 0.01. At a MOI of 0.1,
G47.DELTA. was significantly more efficient at destroying tumor
cells than G207 (FIG. 4), an effect also seen with N18 mouse
neuroblastoma cells. We have found that mouse tumor cells are
generally more resistant to G207 replication than human tumor cells
(Todo et al., Hum. Gene Ther. 10:2741-2755, 1999; Toda et al., Hum.
Gene Ther. 10:385-393, 1999; Todo et al., Cancer Res. 61:153-15
161, 2001).
MHC Class I Expression in G47.DELTA.-Infected Cells
[0045] ICP47 inhibits the function of TAP in translocating peptides
across the endoplasmic reticulum in human cells, but not in mouse
or rat cells (Ahn et al., EMBO J. 15:3247-3255, 20 1996; Tomazin et
al., J. Virol. 72:2560-2563, 1998). Because G47.DELTA. lacks ICP47,
infected cells should have levels of MHC class I expression typical
of uninfected cells. We examined MHC class I down-regulation in
Detroit 551 human diploid fibroblasts using flow cytometric
analyses for human lymphocyte antigen class I (HLA-1). At 48 hours
post-infection, all cells infected with HSV-1 containing an intact
a47 gene (strain F, G207, and R3616) showed a decrease in cell
surface MHC class I, resulting in approximately 40% in peak levels
compared to mock-infected control cells (FIGS. 5A and 5B). By
contrast, there was no down-regulation in G47.DELTA. infected cells
(FIG. 5A). In R47.DELTA.-infected cells, MHC class I expression
remained higher than in strain F or R3616-infected cells, but was
reduced compared to G47.DELTA. (-75% of mock-infected peak levels).
Studies at different time points (6, 24, and 48 hours
post-infection) revealed that differences in MHC class I
down-regulation between ICP47 expressing (G207 and R3616) and
non-expressing (G47.DELTA. and R47.DELTA.) infected cells did not
become apparent until after 6 hours post-infection (FIG. 5B).
[0046] Infection of human melanoma cells with G47.DELTA. also
resulted in higher levels of MHC class I expression than with G207,
although the preclusion of down-regulation was partial. In general,
a greater effect was observed in cell lines with high basal levels
of MHC class I (938 and 1102) compared to those with low levels of
MHC class I (624, 888, and 5 1383) (FIG. 5C).
G47.DELTA.-Infected Human Melanoma Cells Stimulate Human T Cells In
Vitro
[0047] Three human melanoma cell lines were tested for their
abilities to stimulate the matched TIL lines after G47.DELTA.
infection (888 and 1102 with TIL888 (Robbins et al., Cancer Res.
54:3124-3126, 1994)), and 938 with TIL1413 (Kang et al., J.
Immunol. 155:1343-1348, 1995). G47.DELTA.-infected 1102 melanoma
cells, with the highest level of MHC class I expression, caused a
better stimulation of TIL cells compared to G207-infected cells,
resulting in 41% more IFN-.gamma. secretion (FIG. 6). There was
essentially no stimulation of this same TIL line with G47.DELTA. or
G207-infected 888 melanoma cells, which had very low levels of MHC
class I expression. G47.DELTA.-infected 938 melanoma cells
stimulated TIL1413 cells, causing an increase in IFN-.gamma.
secretion that was not statistically significant. The results
demonstrate that the higher MHC class I expression that may ensue
in G47.DELTA. versus G207-infected cells can enhance T cell
stimulation.
Antitumor Efficacy of G47.DELTA. In Vivo
[0048] In a human xenograft model, athymic mice harboring
established subcutaneous U87 MG glioma tumors (approximately 6 mm
in diameter), intraneoplastic inoculation of G207 or G47.DELTA.
(10.sup.6 pfu) followed by a second inoculation 3 days later caused
a significant reduction in U87 MG tumor growth (p<0.05 and
p<0.001 versus control on day 24, 25 respectively; unpaired t
test; FIG. 7). G47.DELTA. treatment was significantly more
efficacious than G207, resulting in reduced average tumor volumes
(FIG. 7). This was reflected in the prolonged survival of animals
and number of `cures` (complete tumor regression with no tumor
regrowth during a 3-month follow up) (Table 1). At the dose tested,
survival was significantly prolonged in the G207-treatment group
(p<0.05 versus mock, Wilcoxon test), and to an even greater
extent in the G47.DELTA.-treated animals (p<0.05 versus G207,
Wilcoxon test).
TABLE-US-00001 TABLE 1 Subcutaneous tumor therapy by G47.DELTA.
Number cured/total treated Tumor (Mouse) Mock G207 G47.DELTA. U87MG
(Athymic) 0/13 3/12 8/12*.sup..dagger. Neuro2a (A/J) 0/10 1/10 3/10
.sup. *p < 0.05 versus G207, .sup..dagger.p < 0.001 versus
Mock, Fisher's test.
[0049] The efficacy of G47.DELTA. was further tested in an
immunocompetent mouse tumor model, subcutaneous, poorly immunogenic
Neuro2a neuroblastoma tumors in syngeneic A/J mice. Established
tumors of approximately 6 mm in diameter were inoculated with mock,
G207, or G47.DELTA. (10.sup.6 pfu) on days 0 and 3. Again, while
both G207 and G47.DELTA. caused a significant reduction in Neuro2a
tumor growth (p<0.05 and p<0.001 versus control on day 15,
respectively; unpaired t test), the efficacy of G47.DELTA. was
greater than that of G207 (FIG. 7). Kaplan-Meier analysis
demonstrated that G207 at this dose did not significantly extend
the survival of Neuro2a tumor-bearing A/J mice, whereas G47.DELTA.
significantly prolonged survival of the animals compared with mock
and G207 (p<0.01 and p<0.05, respectively, Wilcoxon test). In
a 3.5-month follow-up period, there was an increased number of
`cures` among the G47.DELTA.-treated mice (not statistically
significant, Fisher's test; Table 1).
Safety of G47.DELTA. with Intracerebral Inoculation
[0050] To evaluate the toxicity of G47.DELTA. in the brain, A/J
mice were inoculated intracerebrally with mock, strain F
(2.times.10.sup.3 pfu), G207 (2.times.10.sup.6 pfu), or G47.DELTA.
(2.times.10.sup.6 pfu). This dose was the highest dose obtainable
for G207 in the volume injected. Each mouse was monitored daily for
clinical manifestations for 3 weeks. All 8 mock-inoculated mice
survived without any abnormal manifestations, whereas all 10 strain
F-inoculated mice deteriorated rapidly and became moribund within 7
days of inoculation. All 8 G207-inoculated mice and 10
G47.DELTA.-inoculated mice survived. Two of the G207-inoculated
mice and 1 G47.DELTA.-inoculated mouse temporarily manifested (3-6
days post-inoculation) slight hunching or a slightly sluggish
response to external stimuli. This shows that G47.DELTA. is as safe
as G207 when inoculated in the brain of A/J mice at this dose.
[0051] The results described above were obtained using the
following Materials and Methods.
Materials and Methods
Cells
[0052] Vero (African green monkey kidney), SK-N-SH (human
neuroblastoma), U87MG (human glioma), U373MG (human glioma),
Neuro2a (murine neuroblastoma), and Detroit 551 (diploid human
fibroblast) cell lines were purchased from American Type Culture
Collection (Rockville, Md.). SQ20B (head and neck squamous cell
carcinoma) cells were provided by Dr. R. Weichselbaum (University
of Chicago, Chicago, Ill.). N18 murine neuroblastoma cells were
provided by Dr. K. Ikeda (Tokyo Institute of Psychiatry, Tokyo,
Japan). Human melanoma cell lines 624, 888, 938, 1102, and 1383,
and human T cell lines TIL888 and TIL1413, were provided by Dr. J.
Wunderlich (NIH, Bethesda, Md.). All tumor cells were maintained in
Dulbecco's modified Eagle medium supplemented with 10% fetal calf
serum (FCS), 2 mM glutamine, penicillin (100 U/ml), streptomycin
(100 .mu.g/ml), and 2.5 .mu.g/ml Fungizone. Human T cells were
maintained in AIM-V medium (Gibco BRL, Life Technologies,
Rockville, Md.) supplemented with 10% human serum (type AB,
Rh.sup.+; Valley Biomedical Products, Winchester, Va.), interleukin
2 (600 international units (IU)/ml, Chiron Corporation, Emeryville,
Ca.), penicillin (50 U/ml), and 1.25 .mu.g/ml Fungizone.
Generation of G47 .DELTA.
[0053] Plasmid pIE12 contains an 1818 basepair BamHI-EcoRI fragment
from the HSV-1 BamHI.times.fragment, which encompasses the ICP47
coding region (Johnson et al., J. Virol. 68:6347-6362, 1994). A 312
basepair fragment containing the ICP47 coding region between the
BstEII and EcoNI sites was deleted from pIE12 to create pIE12 A
(FIG. 2C). Vero cells were seeded on 6-well dishes at a density of
1-2.times.10.sup.5 cells per well. Transfections were performed
using a range of DNA concentrations from 1 to 3 including a 1:1:1
mixture of G207 DNA (Mineta et al., Nat. Med. 1:938-943, 1995),
pIE12 (intact), and pIE12.DELTA. cleaved with BamHI and Xhol, with
8 .mu.l LipofectAMINE.TM. (Life Technologies), according to the
manufacturer's instructions. The viral progeny from the
transfection were then passaged twice in SK-N-SH cells to enrich
for recombinants that contained a deletion in ICP47 as follows.
SK-N-SH cells were seeded at a density of 5.times.10.sup.6 cells
per 10 cm dish, infected the following day at a range of MOI's from
0.01 to 1 pfu per cell, and harvested at 48 hours post-infection.
This process was then repeated. The deletion in pIE12.DELTA. was
designed to generate a second-site suppressor mutation
of.gamma.34.5 in the virus, and thus permit growth of successful
recombinants on SK-N-SH cells (Mohr et al., EMBO J. 15:4759-4766,
1996). Individual plaques from SK-N-SH-enriched stocks were
plaque-purified on Vero cells under agarose overlays and screened
for the presence of the deletion in ICP47 by Southern blotting. A
stock was prepared from one individual plaque that was homogeneous
for the ICP47 deletion and designated as G47.DELTA.. R47.DELTA. was
constructed similarly, except R3616 (Chou et al., Science
250:1262-1266, 1990) DNA was used in place of G207 DNA (R3616 was
provided by Dr. B. Roizman, University of Chicago, Chicago, Ill.).
Virus titration was performed as previously described (Miyatake et
al., J. Virol. 71:5124-5132, 1997).
Virus Yield Studies
[0054] Cells were seeded on 6-well plates at 5.times.10.sup.5,
8.times.10.sup.5, or 1.6.times.10.sup.6 cells per well. Triplicate
or duplicate wells were infected with the viruses 6-8 hours after
seeding at a MOI of 0.01. At 24 or 48 hours post-infection, the
cells were scraped into the medium and lysed by three cycles of
freeze-thawing. The progeny virus was titered as previously
described with a modification (Miyatake et al., J. Virol.
71:5124-5132, 1997). Briefly, Vero cells were plated in 6-well
plates at 8.times.10.sup.5 cells/well. After 4-8 hours incubation
at 37.degree. C., cells were infected in 1 ml growth medium at
37.degree. C. overnight, after which 1 ml medium containing 0.4%
human IgG (ICN Pharmaceuticals) was added. Wells were incubated at
37.degree. C. for another 2 days, and the number of plaques was
counted after staining with methylene blue (0.5% w/v in 70%
methanol).
In Vitro Cytotoxicity Studies
[0055] In vitro cytotoxicity studies were performed as previously
described (Todo et al., Hum. Gene Ther. 10:2741-2755, 1999), with a
modification for human melanoma cells, which were grown in medium
containing 10% FCS. The number of surviving cells was counted daily
with a Coulter counter (Beckman Coulter, Fullerton, Ca.) and
expressed as a percentage of mock-infected controls.
Flow Cytometric Analyses
[0056] Cells were plated in 6 well plates at 1 x 10.sup.6
cells/well and infected with virus (MOI=3) 24 hours after seeding.
Cells were incubated in the presence of ganciclovir (200 ng/ml) at
39.5.degree. C. for 6, 24, or 48 hours, harvested by
trypsinization, and washed once with 2 ml PBS. G207 and G47.DELTA.
contain temperature-sensitive mutations in ICP4, so they can
replicate at 37.degree. C., but not at 39.5.degree. C. (Mineta et
al., Nat. Med. 1:938-943, 1995. 10 Approximately 5.times.10.sup.5
cells were then used for flow cytometric analyses using
FITC-conjugated anti-human HLA class I antigen (clone W6/32, Sigma,
St. Louis, Mo.) and performed as previously described.
Human T Cell Stimulation Assays
[0057] Human melanoma cells (888, 938, or 1102) were plated in 6
well plates at 5.times.10.sup.5 cells/well, and infected with G207
or G47.DELTA. (MOI=3), or without virus (mock) 24 hours after
seeding. Cells were incubated in growth medium containing 10% FCS
and ganciclovir (200 ng/ml) at 39.5.degree. C. for 3 hours (888) or
6 hours (938 and 1102). Cells were then harvested by scraping, and
a portion was used for cell counting. Infected melanoma cells
(1.times.10.sup.5) were then co-cultured with an equal number of
responding human T cells in 200 .mu.l AIM-V medium containing
ganciclovir (200 ng/ml) in a flat-bottom 96-well plate. Melanomas
888 and 1102 were co-cultured with TIL888 cells, and melanoma 938
was cultured with TIL1413 cells. TIL lines 888 and 1413 both
recognize tyrosinase, a melanoma antigen, in an HLA-A24 restricted
fashion (Robbins et al., Cancer Res. 54:3124-25 3126, 1994; Kang et
al., J. Immunol. 155:1343-1348, 1995). After an 18 hour incubation
at 37.degree. C., the plate was centrifuged at 800 g for 10
minutes, and conditioned medium was collected. IFN-.gamma.
concentrations were measured by enzyme-linked immunosorbent assay
using a human IFN-.gamma. ELISA kit (Endogen, Woburn, Mass.). The
IFN-.gamma. measurements in TIL cells without stimulator cells were
considered the base release levels and used to calculate the
increase of IFN-.gamma. secretion in stimulated TIL cells.
Animal Studies
[0058] Six-week-old female A/J mice and athymic nude mice (BALB/c
nu/nu) were purchased from the National Cancer Institute
(Frederick, Md.), and caged in groups of four or less. Subcutaneous
tumor therapy was performed as previously described (Todo et al., 5
Hum. Gene Ther. 10:2741-2755, 1999; Todo et al., Cancer Res.
61:153-161, 2001).
Intracerebral Inoculation Toxicity Studies
[0059] Mock (PBS containing 10% glycerol), strain F
(2.times.10.sup.3 pfu), G207 (2.times.10.sup.6 pfu), or G47.DELTA.
(2.times.10.sup.6 pfu) in a volume of 5 .mu.l was injected over 5
minutes into the right hemisphere of the brains of 6-week-old
female A/J mice (n=8, 10, 8, and 10, respectively) using a KOPF
stereotactic frame. Cages were then blinded and mice monitored
daily for clinical manifestations for 3 weeks.
[0060] All references cited herein are incorporated by reference in
their entirety. Other embodiments are within the following claims.
Sequence CWU 1
1
1128DNAArtificial SequenceSynthetic Construct 1gggccctgag
ttgcccaatg gcctaaat 28
* * * * *