U.S. patent application number 12/813992 was filed with the patent office on 2010-12-16 for ether and alkyl phospholipid compounds for treating cancer and imaging and detection of cancer stem cells.
Invention is credited to William R. Clarke, Irawati Kandela, Marc Longino, Anatoly Pinchuk, Jamey P. Weichert.
Application Number | 20100316567 12/813992 |
Document ID | / |
Family ID | 43306617 |
Filed Date | 2010-12-16 |
United States Patent
Application |
20100316567 |
Kind Code |
A1 |
Weichert; Jamey P. ; et
al. |
December 16, 2010 |
ETHER AND ALKYL PHOSPHOLIPID COMPOUNDS FOR TREATING CANCER AND
IMAGING AND DETECTION OF CANCER STEM CELLS
Abstract
Methods and compositions utilizing ether and alkyl phospholipid
ether analog compounds for treating cancer and imaging, monitoring,
and detecting cancer stem cells in humans.
Inventors: |
Weichert; Jamey P.;
(Fitchburg, WI) ; Pinchuk; Anatoly; (Madison,
WI) ; Kandela; Irawati; (Madison, WI) ;
Longino; Marc; (Verona, WI) ; Clarke; William R.;
(Colgate, WI) |
Correspondence
Address: |
WOOD, PHILLIPS, KATZ, CLARK & MORTIMER
500 W. MADISON STREET, SUITE 3800
CHICAGO
IL
60661
US
|
Family ID: |
43306617 |
Appl. No.: |
12/813992 |
Filed: |
June 11, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61186600 |
Jun 12, 2009 |
|
|
|
Current U.S.
Class: |
424/1.77 ;
435/29 |
Current CPC
Class: |
A61P 1/18 20180101; A61K
31/661 20130101; A61P 1/00 20180101; A61P 13/08 20180101; A61P
15/00 20180101; A61P 25/00 20180101; A61P 35/04 20180101; C07B
59/00 20130101; A61K 51/0408 20130101; A61K 45/06 20130101; A61P
43/00 20180101; A61K 51/0489 20130101; A61P 11/00 20180101; A61P
13/12 20180101; A61P 35/00 20180101; A61P 17/00 20180101 |
Class at
Publication: |
424/1.77 ;
435/29 |
International
Class: |
A61K 51/00 20060101
A61K051/00; C12Q 1/02 20060101 C12Q001/02; A61P 35/04 20060101
A61P035/04 |
Claims
1. A method of treating cancer comprising administering to a
patient in need thereof a therapeutically effective amount of a
radiolabeled ether or alkyl phospholipid compound of Formula I
##STR00016## where X is an isotope of iodine; n is an integer
between 12 and 30; and Y is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl substituent,
or Formula II ##STR00017## where X is an isotope of iodine; n is an
integer between 12 and 30; Y is selected from the group consisting
of H, OH, COOH, COOR and OR, and Z is selected from the group
comprising N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl substituent,
wherein said therapeutically effective amount of said radiolabeled
ether or alkyl phospholipid compound is sufficient to penetrate
into said cancer stem cells and wherein a population of said cancer
stem cells is reduced.
2. The method of claim 1, wherein said population of cancer stem
cells comprises stem cells of the following cancers: glioma, lung
cancer, squamous cell carcinoma, renal cancer, melanoma, colorectal
cancer, ovarian cancer, prostate cancer, breast cancer, and
pancreatic cancer.
3. The method of claim 1, wherein said isotope of iodine is
.sup.131I.
4. The method of claim 1, wherein said radiolabeled ether or alkyl
phospholipid compound is 18-(p-iodophenyl)octadecyl phosphocholine
and X is .sup.131I.
5. The method of claim 1, wherein X is two or three isotopes of
iodine.
6. The method of claim 1, wherein said method further comprises
another cancer therapy selected from the group consisting of
chemotherapy, radiation therapy, tumor resection, ablative therapy,
and local physical treatment on the basis of cold (cryo), heat
(thermal), radiofrequency, and microwave.
7. A method of imaging a population of cancer stem cells in vivo
comprising administering to a patient in need thereof an effective
amount of a radiolabeled alkyl phospholipid compound of Formula I
##STR00018## where X is an isotope of iodine; n is an integer
between 12 and 30; and Y is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl substituent,
Formula II ##STR00019## where X is an isotope of iodine; n is an
integer between 12 and 30; Y is selected from the group consisting
of H, OH, COOH, COOR and OR, and Z is selected from the group
comprising N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl substituent,
or a fluorescent analog of said radiolabeled ether or alkyl
phospholipid compound, wherein said radioactive ether or alkyl
phospholipid compound or said fluorescent analog penetrates said
cancer stem cells.
8. The method of claim 7, wherein said imaging is performed through
a hybrid scanning utilizing single photon emission computed
tomography (SPECT) or positron emission tomography (PET) and
computed tomography (CT) or magnetic resonance imaging (MRI)
techniques.
9. The method of claim 7, wherein said isotope of iodine is
.sup.124I.
10. The method of claim 7, wherein said radiolabeled ether or alkyl
phospholipid compound is 18-(p-iodophenyl)octadecyl phosphocholine
and X is .sup.124I.
11. The method of claim 7, wherein X is two or three isotopes of
iodine.
12. The method of claim 7, wherein said fluorescent analog has the
following structure: ##STR00020##
13. The method of claim 7, wherein said population of cancer stem
cells comprises stem cells of the following cancers: glioma, lung
cancer, squamous cell carcinoma, renal cancer, melanoma, colorectal
cancer, ovarian cancer, prostate cancer, breast cancer, and
pancreatic cancer.
14. A method of ex vivo or in vitro labeling cancer stem cells
comprising administering to cells suspected of comprising cancer
stem cells an effective amount of a radiolabeled ether or alkyl
phospholipid compound of Formula I ##STR00021## where X is an
isotope of iodine; n is an integer between 12 and 30; and Y is
selected from the group comprising N.sup.+H.sub.3,
HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and N.sup.+(R).sub.3, wherein R
is an alkyl or arylalkyl substituent, or Formula II ##STR00022##
where X is an isotope of iodine; n is an integer between 12 and 30;
Y is selected from the group consisting of H, OH, COOH, COOR and
OR, and Z is selected from the group comprising N.sup.+H.sub.3,
HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and N.sup.+(R).sub.3, wherein R
is an alkyl or arylalkyl substituent, or a fluorescent analog of
said radiolabeled ether or alkyl phospholipid compound, wherein
said cancer stem cells are labeled with said radiolabeled ether or
alkyl phospholipid compound or said fluorescent analog.
15. The method of claim 14, wherein said isotope of iodine is
.sup.124I.
16. The method of claim 14, wherein said radiolabeled ether or
alkyl phospholipid compound is 18-(p-iodophenyl)octadecyl
phosphocholine and X is .sup.124I.
17. The method of claim 14, wherein X is two or three isotopes of
iodine.
18. The method of claim 14, wherein said fluorescent analog has the
following structure: ##STR00023##
19. The method of claim 14, wherein said cancer stem cells comprise
stem cells of one or more of the following cancers: glioma, lung
cancer, squamous cell carcinoma, renal cancer, melanoma, colorectal
cancer, ovarian cancer, prostate cancer, breast cancer, and
pancreatic cancer.
20. The method of claim 14, further comprising a step of
distinguishing said cancer stem cells from non-cancer cells.
Description
BACKGROUND OF THE INVENTION
[0001] Stem cells, which possess the unique ability to undergo
self-renewal and differentiation into tissue-specific cells, give
rise to all tissues in the body. Unlike embryonic stem cells which
can differentiate into many different cell types, tissue specific
stem cells can only form cells unique to one tissue. Recent
advances in stem cell molecular biology techniques have enabled
researchers to examine the concept that a malignant tumor can be
formed and maintained due to the presence of a small number of
cancer-specific stem cells.
[0002] Stem cells can renew themselves. This self-renewal process
of all stem cells, including tumor stem cells, is known to be very
tightly regulated. Many reports in the past several years have
confirmed that small populations of cancer stem cells have been
found in a variety of cancers including glioma, breast, pancreas,
ovarian, hepatocellular carcinoma, and melanoma, to name a few.
Furthermore, it has also been widely reported that current cancer
chemotherapeutic agents which can successfully kill differentiated
tumor cells are actually ineffective against the small population
of cancer stem cells which may be a contributing factor to the
regeneration of cancer cells after chemotherapy. These agents act
by inhibiting a wide variety of known cell signaling, growth
regulation, and cell death mechanisms within these normally
differentiated cancer cells. Several studies have suggested that
long-term ineffectiveness of chemotherapy agents against cancer
stem cells may be due to their lack of penetration into these
cells. Although early in development, this hypothesis may at least
partially explain the regeneration of tumor cells after
chemotherapy.
[0003] Because of its nature, radiation may afford a higher degree
of efficacy in killing cancer stem cells. Although certain tumors
can be effectively treated with external beam radiation, in many
cases, the tumors reappear at a later time. In addition to
chemo-resistance of cancer stem cells, it is now known that glioma
stem cells are also 30% more radio-resistant than regular glioma
cells. This finding is based on radiation applied via external
beam. Systemically administered radiotherapeutics that can target
normally differentiated cancer cells may still hold a significant
advantage over chemotherapeutics due to their collateral killing
ability, wherein radiation emanating from surrounding tumor cells
has the ability to kill a lone stem cell via a "cross-fire" effect
(The "cross-fire" effect is a theory that the radioactive compounds
can kill both the cancer cells to which they attach and the
adjacent tumor cells).
[0004] In addition, systemically administered radiotherapy gives a
prolonged and continuous radiation exposure which appears to be
more effective in tumor cell killing than is intermittent external
radiation therapy. It is even more probable that if a systemically
administered radiotherapeutic agent could actually target the
cancer stem cells and penetrate their membrane, the
radiotherapeutic agent would have a better chance of killing the
cancer stem cell and preventing its eventual regrowth.
[0005] Accordingly, there is a need for radiotherapeutic agents
that can treat cancer either by themselves or in combination with
external beam radiotherapy. In addition, there is a need for new
methods of identifying stem cells, both in vitro and in vivo.
BRIEF SUMMARY OF THE INVENTION
[0006] In one aspect, this invention relates to a method of
treating cancer comprising administering to a patient in need
thereof a therapeutically effective amount of a radiolabeled ether
or alkyl phospholipid compound of Formula I
##STR00001## [0007] where X is an isotope of iodine; n is an
integer between 12 and 30; and Y is selected from the group
comprising N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
or Formula II
##STR00002##
[0008] where X is an isotope of iodine; n is an integer between 12
and 30; Y is selected from the group consisting of H, OH, COOH,
COOR and OR, and Z is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
[0009] wherein said therapeutically effective amount of said
radiolabeled ether or alkyl phospholipid compound is sufficient to
penetrate into said cancer stem cells and wherein a population of
said cancer stem cells is reduced.
[0010] The therapeutically effective amount that is sufficient to
penetrate into said cancer stem cells is preferably between 0.21-21
mg (equivalent to a 7-700 mCi, total mass dose range) and between
0.03-0.21 mg/kg (equivalent to 1-7 mCi/kg, by weight dose
range).
[0011] For a therapy in humans, a preferred isotope of iodine is
.sup.131I, although other radioactive isotopes, including
.sup.123I, .sup.124I, and .sup.125I can also be used.
[0012] In one embodiment of the invention, the alkyl phospholipid
compound labeled with a nonradioactive ("cold") isotope of iodine
(e.g., .sup.127I) can be utilized to treat cancer stem cells.
[0013] In the most preferred embodiment, the radiolabeled compound
is CLR1404 (18-(p-iodophenyl)octadecyl phosphocholine) radiolabeled
with .sup.131I.
[0014] In addition, ether and alkyl phospholipid compounds having
more than one radioactive iodine may be used for the purposes of
the present invention. Some representative structures are as
follows:
##STR00003##
[0015] The part of the molecule after the vertical wavy line is the
same as in the molecules with one Iodine attached to the phenyl
ring.
[0016] In one embodiment, the cancer is solid cancer.
[0017] In one embodiment, the solid cancers are selected from the
group consisting of lung cancer, breast cancer, glioma, squamous
cell carcinoma, prostate cancer, melanoma, renal cancer, colorectal
cancer, ovarian cancer, pancreatic cancer, sarcoma, and stomach
cancer.
[0018] In another embodiment, the invention provides pharmaceutical
compositions comprising radiolabeled ether or alkyl phospholipid
compounds as described in the application formulated for use in the
treatment of cancer wherein the radiolabeled ether or alkyl
phospholipid compounds penetrate cancer stem cells.
[0019] In another embodiment, the invention relates to method of
imaging a population of cancer stem cells in vivo comprising
administering to a patient in need thereof an effective amount of a
radiolabeled ether or alkyl phospholipid compound of Formula I
##STR00004## [0020] where X is an isotope of iodine; n is an
integer between 12 and 30; and Y is selected from the group
comprising N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
or Formula II
##STR00005##
[0021] where X is an isotope of iodine; n is an integer between 12
and 30; Y is selected from the group consisting of H, OH, COOH,
COOR and OR, and Z is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
[0022] wherein said radiolabeled ether or alkyl phospholipid
compound penetrates said cancer stem cells.
[0023] For imaging in humans, a preferred isotope of iodine is
.sup.124I, although other radioactive isotopes, including .sup.123I
and .sup.131I can be used, too.
[0024] In one preferred embodiment, the radiolabeled ether or alkyl
phospholipid compound is CLR1404 (18-(p-iodophenyl)octadecyl
phosphocholine) radiolabeled with .sup.124I.
[0025] In other embodiments of the invention, fluorescent analogs
of PLE compounds may be used in the claimed imaging methods. For
example, the invention specifically contemplates the use of CLR1501
compound, which has the following structure:
##STR00006##
[0026] The application specifically incorporates by reference all
fluorescent PLE analogs described in the pending patent application
Ser. Nos. 12/463,970; 12/463,978; 12/463,983; 12/463,990; and
12/463,998.
[0027] The imaging can be performed through a hybrid scanning,
utilizing a functional imaging modality, such as single photon
emission computed tomography (SPECT) or positron emission
tomography (PET) in combination with computed tomography (CT)
and/or magnetic resonance imaging (MRI) techniques, and
combinations thereof.
[0028] In other embodiments, the invention provides methods of ex
vivo or in vitro labeling cancer stem cells comprising
administering to cells suspected of comprising cancer stem cells an
effective amount of a radiolabeled ether or alkyl phospholipid
compound of Formula I or II. In other embodiments of the invention,
the above-described fluorescent analogs of phospholipid compounds
may be used for the labeling.
[0029] In other embodiments, the described compounds can be used
for identifying cancer stem cells in vivo, by administering the
compounds to an animal and then identifying and/or quantifying stem
cells of any type in any organ or tissue.
DETAILED DESCRIPTION OF THE INVENTION
[0030] We have developed several series of tumor-selective
radiolabeled ether and alkyl phospholipid compounds for imaging,
characterization, and treatment of malignant tumors. Thus far, the
lead compound, CLR1404, has shown striking uptake and prolonged
selective retention properties in over fifty solid xenograft and
spontaneous human tumor and rodent tumor models. Unlike
.sup.18F-Fluorodeoxyglucose (.sup.18F-FDG), the current gold
standard for oncologic imaging, CLR1404 does not localize in benign
or premalignant lesions or in inflammatory lesions. Cellular
signaling and regulation of phospholipids, including
phospholipase-D and its isoforms, as well as Phosphatase and Tensin
Homologue Deleted from Chromosome-10 (PTEN) and
phosphatidylinositol phosphate (PIPn) pathways, are known to be
directly involved in upstream regulation of many key oncogenic
pathways. We now have strong evidence that the uptake and retention
of our PLE analogs is due at least in part to these upstream
regulation and signaling cancer cell pathways. Other
non-radioactive members of the "anti-tumor alkyl-phospholipid"
class of molecules have been shown to induce tumor cell apoptosis
through inhibition of AKT-dependent downstream signaling; the very
mechanism which is thought to be important in enhancing malignant
stem cell survival in response to either chemotherapy or
radiation.
[0031] This invention relates to a discovery that the unique
properties of ether and alkyl phospholipid compounds, especially
CLR1404, including their prolonged selective retention in malignant
cells, and their ability to inhibit AKT-dependent survival
mechanisms, can be utilized to treat and/or detect cancer stem
cells.
[0032] For purposes of the present invention, the terms "PLE
compounds" and "PLE analogs" are interchangeable and refer to ether
and alkyl phospholipid compounds as described in the invention.
[0033] For purposes of the present invention, the term "treating"
refers to reversing, alleviating, inhibiting, or slowing the
progress of the disease, disorder, or condition to which such term
applies, or one or more symptoms of such disease, disorder, or
condition.
[0034] The term "cancer stem cell" refers to a cell with
tumor-initiating and tumor-sustaining capacity.
[0035] The term "therapeutically effective amount" refers to a
sufficient amount of the compound to reduce the number of cancer
stem cells. It will be understood, however, that the total daily
usage of the compounds and compositions of the present invention
will be decided by the attending physician within the scope of
sound medical judgment. The specific therapeutically effective dose
level for any particular patient will depend upon a variety of
factors including the specific cancer being treated, the stage of
the cancer, activity of the specific compound employed; the
specific composition employed; the age, body weight, general
health, sex and diet of the patient; the time of administration,
route of administration, and rate of excretion of the specific
compound employed; the duration of the treatment; drugs used in
combination or coincidental with the specific compound employed;
and like factors well known in the medical arts.
[0036] The term "crystalline forms" and related terms herein refers
to the various crystalline modifications of a given substance,
including, but not limited to, polymorphs, solvates, hydrates,
co-crystals and other molecular complexes, as well as salts,
solvates of salts, hydrates of salts, other molecular complexes of
salts, and polymorphs thereof.
[0037] The compounds of the invention encompass any deuterated
versions of the compounds.
[0038] The compounds of the invention may exist in different
isomeric (e.g. enantiomers and distereoisomers) and enol forms. The
invention contemplates all such isomers, both in pure form and in
admixture, including racemic mixtures.
[0039] The compounds of the invention encompass pharmaceutically
acceptable salts of the phosphocholine portion of the compounds.
The compounds of the invention are also preferably inner salts
(zwitterions) themselves.
[0040] The term "pharmaceutically acceptable salts" is meant to
include salts of active compounds which are prepared with
relatively nontoxic acids. Acid addition salts can be obtained by
contacting the neutral form of such compounds with a sufficient
amount of the desired acid, either neat or in a suitable inert
solvent. Examples of pharmaceutically acceptable acid addition
salts include those derived from inorganic acids like hydrochloric,
hydrobromic, nitric, carbonic, monohydrogencarbonic, phosphoric,
monohydrogenphosphoric, dihydrogenphosphoric, sulfuric,
monohydrogensulfuric, hydriodic, or phosphorous acids and the like,
as well as the salts derived from relatively nontoxic organic acids
like acetic; propionic; isobutyric; maleic; malonic; benzoic;
succinic; suberic; fumaric; mandelic; phthalic; benzenesulfonic;
toluenesulfonic, including p-toluenesulfonic, m-toluenesulfonic,
and o-toluenesulfonic; citric; tartaric; methanesulfonic; and the
like. Also included are salts of amino acids such as arginate and
the like, and salts of organic acids like glucuronic or
galactunoric acids and the like (see, for example, Berge et al. J.
Pharm. Sci. 66:1-19 (1977)).
[0041] As used herein, a salt or polymorph that is "pure," i.e.,
substantially free of other polymorphs, contains less than about
10% of one or more other polymorphs, preferably less than about 5%
of one or more other polymorphs, more preferably less than about 3%
of one or more other polymorphs, most preferably less than about 1%
of one or more other polymorphs.
[0042] The terms, "polymorphs" and "polymorphic forms" and related
terms herein refer to crystal forms of a molecule. Different
polymorphs may have different physical properties such as, for
example, melting temperatures, heats of fusion, solubilities,
dissolution rates and/or vibrational spectra as a result of the
arrangement or conformation of the molecules in the crystal
lattice. The differences in physical properties exhibited by
polymorphs affect pharmaceutical parameters such as storage
stability, compressibility and density (important in formulation
and product manufacturing), and dissolution rates (an important
factor in bioavailability). Polymorphs of a molecule can be
obtained by a number of methods, as known in the art. Such methods
include, but are not limited to, melt recrystallization, melt
cooling, solvent recrystallization, desolvation, rapid evaporation,
rapid cooling, slow cooling, vapor diffusion and sublimation.
[0043] The term "alkyl," as used herein refers to monovalent
saturated aliphatic hydrocarbon groups, particularly, having up to
about 11 carbon atoms, more particularly as a lower alkyl, from 1
to 8 carbon atoms and still more particularly, from 1 to 6 carbon
atoms. The hydrocarbon chain may be either straight-chained or
branched. This term is exemplified by groups such as methyl, ethyl,
n-propyl, isopropyl, n-butyl, iso-butyl, tent-butyl, n-hexyl,
n-octyl, tert-octyl and the like. The term "lower alkyl" refers to
alkyl groups having 1 to 6 carbon atoms. The term "alkyl" also
includes "cycloalkyl" as defined below.
[0044] The term "heteroalkyl," by itself or in combination with
another term, means, unless otherwise stated, a stable straight or
branched chain, or cyclic hydrocarbon radical, or combinations
thereof, consisting of the stated number of carbon atoms and from
one to three heteroatoms selected from the group consisting of O,
N, Si and S, and wherein the nitrogen and sulfur atoms may
optionally be oxidized and the nitrogen heteroatom may optionally
be quaternized. The heteroatom(s) O, N and S may be placed at any
interior position of the heteroalkyl group. The heteroatom Si may
be placed at any position of the heteroalkyl group, including the
position at which the alkyl group is attached to the remainder of
the molecule. Examples include --CH.sub.2--CH.sub.2--O--CH.sub.3,
--CH.sub.2--CH.sub.2--NH--CH.sub.3,
--CH.sub.2--CH.sub.2--N(CH.sub.3)--CH.sub.3,
--CH.sub.2--S--CH.sub.2--CH.sub.3,
--CH.sub.2--CH.sub.2--S(O)--CH.sub.3,
--CH.sub.2--CH.sub.2--S(O).sub.2--CH.sub.3,
--CH.dbd.CH--O--CH.sub.3, --Si(CH.sub.3).sub.3,
--CH.sub.2--CH.dbd.N--OCH.sub.3, and
--CH.dbd.CH--N(CH.sub.3)--CH.sub.3. Up to two heteroatoms may be
consecutive, such as, for example, --CH.sub.2--NH--OCH.sub.3 and
--CH.sub.2--O--Si(CH.sub.3).sub.3. Also included in the term
"heteroalkyl" are those radicals described in more detail below as
"heteroalkylene" and "heterocycloalkyl."
[0045] "Aryl" refers to a monovalent aromatic hydrocarbon group
derived by the removal of one hydrogen atom from a single carbon
atom of a parent aromatic ring system. Typical aryl groups include,
but are not limited to, groups derived from aceanthrylene,
acenaphthylene, acephenanthrylene, anthracene, azulene, benzene,
chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene,
hexylene, as-indacene, s-indacene, indane, indene, naphthalene,
octacene, octaphene, octacene, ovalene, penta-2,4-diene, pentacene,
pentalene, pentaphene, perylene, phenalene, phenanthrene, picene,
pleiadene, pyrene, pyranthrene, rubicene, triphenylene,
trinaphthalene and the like. Particularly, an aryl group comprises
from 6 to 14 carbon atoms.
[0046] The term "subject" is defined herein to include animals such
as mammals, including, but not limited to, primates (e.g., humans,
monkeys, apes), cows, sheep, goats, horses, dogs, cats, rabbits,
rats, mice and the like. In preferred embodiments, the subject is a
human.
[0047] As used herein, the term "about" or "approximately" means an
acceptable error for a particular value as determined by one of
ordinary skill in the art, which depends in part on how the value
is measured or determined. In certain embodiments, the term "about"
or "approximately" means within 1, 2, 3, or 4 standard deviations.
In certain embodiments, the term "about" or "approximately" means
within 50%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%,
0.5%, or 0.05% of a given value or range.
[0048] Thus, in one aspect, this invention relates to a method of
treating cancer comprising administering to a patient in need
thereof a therapeutically effective amount of a radiolabeled ether
or alkyl phospholipid compound of Formula I
##STR00007## [0049] where X is an isotope of iodine; n is an
integer between 12 and 30; and Y is selected from the group
comprising N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
or Formula II
##STR00008##
[0050] where X is an isotope of iodine; n is an integer between 12
and 30; Y is selected from the group consisting of H, OH, COON,
COOR and OR, and Z is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
[0051] wherein said therapeutically effective amount of said
radiolabeled ether or alkyl phospholipid compound is sufficient to
penetrate into said cancer stem cells and wherein a population of
said cancer stem cells is reduced.
[0052] The therapeutically effective amount that is sufficient to
penetrate into said cancer stem cells is preferably between 0.21-21
mg (equivalent to a 7-700 mCi, total mass dose range) and between
0.03-0.21 mg/kg (equivalent to 1-7 mCi/kg, by weight dose
range).
[0053] These amounts were calculated using the current drug product
(CLR1401) total mass dose value of 0.15 mg/mL and an activity
concentration value of 5.0 mCi/mL at injection.
[0054] In one embodiment, the invention provides pharmaceutical
compositions comprising radiolabeled ether or alkyl phospholipid
compounds as described in the application formulated for use in the
treatment of cancer wherein the radiolabeled ether or alkyl
phospholipid compounds penetrate cancer stem cells.
[0055] In a preferred embodiment, the population of cancer stem
cells comprises stem cells of the following cancers: glioma, lung
cancer, squamous cell carcinoma, renal cancer, melanoma, colorectal
cancer, ovarian cancer, prostate cancer, breast cancer, and
pancreatic cancer.
[0056] For a therapy in humans, a preferred isotope of iodine is
.sup.131I, although other radioactive isotopes, including
.sup.123I, .sup.124I, and .sup.125I can be used, too. In one
embodiment, an ether or alkyl phospholipid compound tagged with
"cold" iodine (e.g., .sup.127I) can be utilized to treat cancer
stem cells.
[0057] In the most preferred embodiment, the radiolabeled compound
is CLR1404 (18-(p-iodophenyl)octadecyl phosphocholine) radiolabeled
with .sup.131I.
[0058] In addition, ether and alkyl phospholipid compounds having
more than one radioactive iodine may be used for the purposes of
the present invention. Some representative structures are as
follows:
##STR00009##
[0059] The part of the molecule after the vertical wavy line is the
same as in the molecules with one Iodine attached to the phenyl
ring.
[0060] In another embodiment, the invention also relates to a
combination therapy, wherein the reduction of cancer stem cells
with radiolabeled ether or alkyl phospholipid compounds takes place
concurrently, subsequently, or prior to another treatment.
[0061] In a preferred embodiment, the other treatment is selected
from radiotherapy, chemotherapy, tumor resection, ablative
therapies, and local physical treatment on the basis of cold
(cryo), heat (thermal), radiofrequency, and microwave.
[0062] In some embodiments of the invention, the claimed methods
enhance the radiosensitivity of cancer stem cells. This is because
PLE compounds, as described in the application, are able to
penetrate cancer stem cells through direct uptake. Thus, the
invention allows enhancing the overall radiation dose delivered to
cancer stem cells by radiotherapy. In one embodiment, the invention
allows enhancing the overall radiation dose delivered to cancer
stem cells by radiotherapy by about 30%.
[0063] In another embodiment, the claimed methods may allow killing
(or reducing the population of) cancer stem cells without any
external radiation or any other cancer therapy. The killing of
cancer stem cells by the described PLE analogs may be due to direct
uptake of the PLE analogs into cancer stem cells and/or due to
collateral effects from killing neighboring cancer cells.
[0064] In another embodiment, the invention relates to a method of
imaging a population of cancer stem cells in vivo comprising
administering to a patient in need thereof an effective amount of a
radiolabeled alkyl phospholipid compound of Formula I
##STR00010## [0065] where X is an isotope of iodine; n is an
integer between 12 and 30; and Y is selected from the group
comprising N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
or Formula II
##STR00011##
[0066] where X is an isotope of iodine; n is an integer between 12
and 30; Y is selected from the group consisting of H, OH, COOH,
COOR and OR, and Z is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
[0067] wherein said radiolabeled ether or alkyl phospholipid
compound penetrates said cancer stem cells.
[0068] In a preferred embodiment, the population of cancer stem
cells comprises stem cells of the following cancers: glioma, lung
cancer, squamous cell carcinoma, renal cancer, melanoma, colorectal
cancer, ovarian cancer, prostate cancer, breast cancer, and
pancreatic cancer.
[0069] For imaging in humans, a preferred isotope of iodine is
.sup.124I, although other radioactive isotopes, including .sup.123I
and .sup.131I can also be used.
[0070] In the most preferred embodiment, the radiolabeled compound
is CLR1404 (18-(p-iodophenyl)octadecyl phosphocholine) radiolabeled
with .sup.124I.
[0071] PLE compounds having more than one iodine atom attached to
the phenyl ring, as described above, may also be used in the
imaging methods.
[0072] In other embodiments of the invention, fluorescent analogs
of PLE compounds may be used in the claimed imaging methods. For
example, the invention specifically contemplates the use of CLR1501
compound, which has the following structure:
##STR00012##
[0073] The application specifically incorporates by reference all
fluorescent PLE analogs described in the pending patent application
Ser. Nos. 12/463,970; 12/463,978; 12/463,983; 12/463,990; and
12/463,998.
[0074] The imaging can be performed through a hybrid scanning,
utilizing a functional imaging modality, such as single photon
emission computed tomography (SPECT) or positron emission
tomography (PET) in combination with computed tomography (CT)
and/or magnetic resonance imaging (MRI) techniques, and
combinations thereof.
[0075] In another embodiment, the invention relates to a method of
ex vivo or in vitro labeling cancer stem cells comprising
administering to cells suspected of comprising cancer stem cells an
effective amount of a radiolabeled ether or alkyl phospholipid
compound of Formula I
##STR00013##
[0076] where X is an isotope of iodine; n is an integer between 12
and 30; and Y is selected from the group comprising N.sup.+H.sub.3,
HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and N.sup.+(R).sub.3, wherein R
is an alkyl or arylalkyl substituent,
or Formula II
##STR00014##
[0077] where X is an isotope of iodine; n is an integer between 12
and 30; Y is selected from the group consisting of H, OH, COOH,
COOR and OR, and Z is selected from the group comprising
N.sup.+H.sub.3, HN.sup.+(R).sub.2, N.sup.+H.sub.2R, and
N.sup.+(R).sub.3, wherein R is an alkyl or arylalkyl
substituent,
[0078] wherein said cancer stem cells are labeled with said
radiolabeled ether or alkyl phospholipid compound.
[0079] PLE compounds having more than one iodine atom attached to
the phenyl ring, as described above, may also be used in the
labeling methods.
[0080] In other embodiments of the invention, the above-described
fluorescent analogs of PLE compounds may be used in the labeling
methods.
[0081] In some embodiments, this method allows to detect and/or
separate cancer stem cells from other types of cells.
[0082] In other embodiments, the described compounds can be used
for identifying cancer stem cells in vivo, by administering the
compounds to an animal and then identifying and/or quantifying stem
cells of any type in any organ or tissue. These methods may be used
to facilitate diagnosis and/or treatment of diseases or to study
physiological processes in animals.
[0083] The compounds may be administered through any suitable
method, including injection, ingestion, and topical
administration.
[0084] The described methods may further comprise a step of
separating the cancer stem cells from non-cancer cells.
[0085] In addition, these methods may be used to monitor the
response to therapies which affect the growth of stem cells in
animals, including humans. The therapies may either reduce the
growth of stem cells or stimulate the growth of stem cells.
[0086] The following prophetic Examples demonstrate some aspects of
the invention. The Examples are not meant to limit the invention in
any way.
EXAMPLES
Example 1
Testing CLR1501 In Vitro to Determine if the Compound Enters Cancer
Stem Cells
[0087] An objective of this experiment is to determine whether an
alkyl phospholipid compound CLR1501 (a fluorescent version of
CLR1404) enters cancer stem cells in culture utilizing confocal
microscopy.
[0088] CLR1501 has the following structure:
##STR00015##
[0089] We have shown in cell culture studies that CLR1501 is
preferentially taken up by a variety of tumor cells relative to
their normal host tissue cells. The agent initially associates with
outer cell membranes, becomes internalized, and then associates
with other subcellular organelles and membranes. It does not appear
to enter the nucleus even after 24 hours.
[0090] A similar experiment utilizing CLR1501 could be performed to
demonstrate that alkyl phospholipid compounds can penetrate cancer
stem cells. A comparison in brain tumors, for example, would
consist of doing a parallel comparison of CLR1501 uptake in
cultured glial cells (normal brain neuronal cells), normally
differentiated glioma tumor cells, and enriched glioma cancer
(isolated from human gliomas, separated using cancer stem cell
markers, and grown in culture) stem cells. Following exposure to
CLR1501, cells from each cohort would be removed from their
cultured environments and subjected to z-stack confocal microscopy
imaging over time and the uptake of the agent quantified to
identify differences in total uptake and rates of uptake as well as
retention.
[0091] A similar experiment can be done with radiolabeled CLR1404
with determination of the amount of compound that is retained in
lysates of exposed stem cells.
Example 2
Testing CLR1404 In Vivo to Determine if the Compound Enters Cancer
Stem Cells
[0092] An objective of this experiment is to determine whether
.sup.124I-CLR1404 enters cancer stem cells in vivo utilizing
microPET/CT/MRI scanning.
[0093] Utilizing microPET/CT hybrid scanning of our tumor-bearing
mouse models, we can quantitatively monitor tumor uptake and
retention three-dimensionally in intact rodent tumor models,
including xenografts of human tumors in immune-compromised mice, as
well as spontaneous mouse and rat tumor models.
[0094] To evaluate the potential uptake of CLR1404 into cancer stem
cells, using glioma as an example, we would perform in vivo
microPET/CT/MRI hybrid scanning of anesthetized animals bearing
orthotopic brain tumors derived from human glioma stem cells.
Isolation of these cells would be similar to that described in
Example 1, with the exception that the tumor stem cells would be
implanted orthotopically into the mouse brain. A comparison would
also be done with normal gliomas of non-stem cell derivation.
Following in vivo imaging utilizing .sup.124I-CLR1404 at several
time points from 0-7 days, the tumors would be excised and scanned
ex vivo and then the tumor isolated and counted for radioactivity
in order to compare tumor to normal brain ratios and also to
compare tumor derivations.
Example 3
Testing CLR1404 In Vivo to Determine if the Compound Reduces the
Number of Cancer Stem Cells
[0095] An objective of this experiment is to determine whether
.sup.125I- or .sup.131I-CLR1404 can kill cancer stem cells and
compare survival of normally differentiated glioma cells.
[0096] The same glioma model as proposed for the experiments in
Examples 1 and 2 may be utilized. It would be desirable to compare
the therapeutic efficacy of both .sup.125I-CLR1404 and
.sup.131I-CLR1404. Accordingly, cohorts of brain tumor bearing mice
would consist of sham operated (n=3), normally differentiated
glioma (n=3), and stem cell derived glioma (n=6). Tumor would
initially be confirmed noninvasively with high field MRI imaging
prior to administration of the agent. Animals would receive a
mixture of imaging (.sup.124I) and therapeutic (.sup.125I or
.sup.131I) agent at T.sub.0 and scanned up to 4 days post injection
to determine suitable tumor targeting. After a predetermined period
of time, animals will be euthanized, tumors excised, cells digested
and subjected to appropriate cell culture conditions. Cell growth
of regularly differentiated glioma cells as well as gliomal stem
cell derived spheroids will be quantified and compared to determine
if there is differential killing effect for either isotope in each
cell population.
* * * * *