1. Field of the Invention
This invention relates to compositions of matter and methods of using said compositions for inhibiting human reductase enzyme(s) that destroy the cell-killing efficacy of anthracycline cancer drugs, and that catalyze the formation of dangerous or damaging metabolites during or after cancer treatment. More specifically, embodiments of the invented compositions and methods of using said compositions inhibit human carbonyl reductase, thus inhibiting conversion of anthracycline to metabolites that are less effective cell-killing agents and that also lead to cardiotoxicity during or after treatment of cancer patients. Thus, the invented compositions and methods are believed to reduce the amount needed, and the cardiotoxic side-effects, of anthracyclines in cancer treatment.
2. Related Art
Anthracyclines are a family of drugs that are effective anti-neoplastic agents, and are commonly used to treat cancer, including leukemia, soft tissue sarcomas, and breast and lung cancer. Anthracyclines intercalate into DNA and are described as topoisomerase Type II poisons. The anthracycline family comprises adriamycin, daunomycin, daunorubicin, doxorubicin, epirubicin, and idarubicin. See, for example, the representations of doxorubicin and daunorubicin shown in
While the anthracyclines are known to be potent anti-tumor drugs, their use has been limited due to potentially life-threatening cardiotoxicity associated therewith. This problem may be described as cumulative dose-dependent cardiotoxicity, which can ultimately result in congestive heart failure. There is significant evidence that the toxic effects on the heart associated with anthracycline-based cancer treatment are largely attributable to anthracycline alcohol metabolite(s) that form and accumulate in cardiac cells. These metabolites are known to disrupt several key processes in heart muscle and thus impair heart function. See, for example, Minotti, et al., “Anthracyclines: Molecular Advances and Pharmacologic Developments in Antitumor Activity and Cardiotoxicity,” Pharmacological Reviews, 56: 185-229, 2004.
Enzymes belonging to the aldo-keto reductase and short chain dehydrogenase/reductase protein superfamilies catalyze the formation of the anthracycline metabolites. Of these enzymes, carbonyl reductase (“CR”) has been specifically linked to the development of anthracycline-induced cardiotoxicity. See, for example, Olson, et al., “Protection from Doxorubicin-Induced Cardiac Toxicity in Mice with a Null Allele of Carbonyl Reductase 1,” Cancer Research, 63, 6602-6606, Oct. 15, 2003. Findings that support the hypothesis that CR is a key factor in anthracycline-induced cardiotoxicity include studies wherein heart-specific over-expression of human carbonyl reductase in transgenic mice substantially increased the development of cardiotoxicity after anthracycline treatment. See, for example, Forrest, et al., “Human Carbonyl Reductase Overexpression in the Heart Advances the Development of Doxorubicin-induced Cardiotoxicity in transgenic Mice,” Cancer Research, 60, 5158-5164, Sep. 15, 2000.
Further, several studies have implicated the reduction of anthracyclines by carbonyl reductase in drug resistance. This is largely because the alcohol metabolites of anthracyclines have been shown to exhibit significantly reduced anticancer properties. Relevant to this are studies performed by Tanaka, et al. (reported in Tanaka, et al., “An Unbiased Cell Morphology-Based Screen for New, Biologically Active Small Molecules,” PLoS Biology, volume 3, issue 5, 0764-0776, May 2005). Tanaka, et al. report that a potent inhibitor of human carbonyl reductase (3-(7-isopropyl-4-(methylamino)-7H-pyrrolo[2,3-d]pyrimidin-5-yl)phenol, also known as hydroxyl-PP-me), when co-administered with daunorubicin to A549 adenocarcinoma cells, was found to enhance the cytotoxicity of daunorubicin. It was concluded that inhibition of carbonyl reductase led to enhanced cytotoxicity of daunorubicin.
Therefore, the inventor believes that there is a need for pharmaceutical interventions that block the action of human carbonyl reductase. The inventor believes that such pharmaceutical interventions will increase the efficacy of anthracycline therapy in cancer/tumor treatment by preventing or reducing conversion of anthracyclines to less potent cell-killing species and by reducing the risk of cardiotoxicity.
The present invention comprises compositions of matter, and methods of treating patients with the compositions of matter, to prevent or reduce conversion in the human body of anthracycline drugs to metabolites that are less effective for cancer treatment and that are also believed to produce cardiotoxicity during or after cancer treatment. Hence, by using embodiments of the invention, the effectiveness of a given dose of anthracycline drugs may increase and the cardiotoxicity typically associated with said treatment may lessen.
Embodiments of the invention comprise inhibiting carbonyl reductase enzyme(s), and/or other enzyme(s) that catalyze anthracycline conversion to anthracycline metabolites. This inhibition has the direct effect of maintaining concentrations of anthracyclines, which are desirable for their cell-killing abilities, and, hence, for their cancer-cell-killing abilities. This inhibition also has the indirect effect of reducing formation of metabolites that build up during or after treatment with anthracycline cancer drugs, said metabolites being ones that are believed to disrupt heart muscle processes and therefore interfere with heart function. Therefore, much less anthracycline drug is expected to be needed to achieve the desired killing of cells, and much less cardiotoxic metabolite will be produced over the duration of the cancer treatment.
Preferred embodiments of the invention comprise treating cancer patients with a pharmaceutical composition comprising 2,2′-thio-bis(4,6-dichlorophenol) (also called “bithionol”) or “bis(2-hydroxy-3,5-dichlorophenyl)sulfide”) and/or 2,2′-sulfinyl-bis(4,6-dichlorophenol) (also called “bithionol sulfoxide”) and/or derivatives or analogs thereof. The preferred composition of bithionol, bithionol sulfoxide, and/or derivatives or analogs thereof, may be administered to a human (or other mammal) in a pharmaceutical composition also comprising at least one anthracycline compound, or may be administered separately from the at least one anthracycline compound either at the same as the anthracycline(s), or any different time found to be effective for inhibiting formation of the anthracycline metabolites.
Therefore, an object of the present invention is to inhibit one or more of the members of the aldo-keto reductase and/or short chain dehydrogenase/reductase protein superfamilies, which catalyze the conversion of anthracyclines to anthracycline metabolites. The preferred compositions and methods are adapted to inhibit member(s) of these superfamilies that is/are currently associated with cardiotoxicity from anthracycline chemotherapy, that is, human carbonyl reductase. A synergistic effect of inhibiting said reductase enzyme is expected to be that lower dosages of the anthracycline drug will be effective for cancer-cell-killing.
Referring to the figures, there are illustrated several, but not the only, embodiments, and text results from embodiments, of the invented composition of matter and methods for enhancing the efficacy of anthracycline drug cancer treatment and/or reducing side-effects thereof. The preferred methods and compositions of matter may maintain effective concentrations of anthracycline(s) during cancer treatment, by preventing or reducing conversion of the anthracycline(s) to metabolites that are less effective or ineffective as cancer-cell-killing species. The preferred methods and compositions also prevent or reduce the potentially life-threatening cardiotoxicity associated with anthracycline chemotherapy for cancer patients.
The preferred compositions of matter comprise one or both of 2,2′-thio-bis(4,6-dichlorophenol) (also called “bithionol” or “bis(2-hydroxy-3,5-dichlorophenyl)sulfide”) and 2,2′-sulfinyl-bis(4,6-dichlorophenol) (also called “bithionol sulfoxide”). See
The disease or condition of cardiotoxicity related to anthracycline drugs is briefly described above in the Related Art Section. Multiple studies point to human carbonyl reductase (such as carbonyl reductase 1) having a role in the production of the anthracycline metabolites believed to cause cardiotoxity side effects in cancer patients either near the time of the chemotherapy or at some later time. See
In addition, as the anthracycline metabolite(s) are believed to not possess the anti-neoplastic properties of the parent anthracycline(s), carbonyl reductase may also contribute to anthracycline drug resistance. In other words, carbonyl reductase may reduce anthracycline concentrations in the human body by catalyzing conversion of the anthracycline, and, hence, may reduce the amount of cancer cells killed by a given dose of anthracycline drug.
The preferred compositions and methods, comprising 2,2′-thio-bis(4,6-dichlorophenol) (called hereafter “bithionol”) and 2,2′-sulfinyl-bis(4,6-dichlorophenol) (called hereafter “bithionol sulfoxide”), have been shown by the inventor to inhibit carbonyl reductase, and are envisioned to allow an increase in anthracycline chemotherapy by offsetting the negative side effects of this chemotherapy. Also, as discussed above, the preferred compositions and methods may decrease anthracycline drug resistance, further improving the results of anthracycline chemotherapy.
The inventor believes that embodiments of the invention may comprise taking bithionol and/or bithionol sulfoxide orally, which has advantages for most patients and their care-givers. Bithionol has been used in the past as an anti-microbial compound, and, in internal medicine, for treating liver fluke infections, but, to the inventor's knowledge, neither bithionol nor bithionol sulfoxide has previously been used in any process for improving efficacy of drugs used in cancer treatment or for treating or preventing side effects of cancer treatment or cardiotoxicity. However, the inventor believes that previously-used clinical doses of bithionol for liver fluke treatment may provide a starting place for finding safe doses for cancer treatment enhancement and cardiotoxicity prevention/treatment. For example, oral doses (given every other day for 10-15 doses) in the range of 30-50 mg of bithionol per kilogram of human body weight have been used to treat liver flukes, and this may be a starting place for determining a safe dose for embodiments of this invention. See Bacq, et al., “Successful Treatment of Acute Fascioliasis with Bithionol,” Hepatology, 1991; 14(6); 1066-9 (ISSN: 0270-9139). While the above-reported dose has been effective and considered safe in the context of liver fluke treatment, the dose of bithionol and/or bithionol sulfoxide may be increased in the context of the invented cancer-treatment methods, if the side-effects of the higher doses are relatively benign compared to the benefits of the increased anthracycline-based cancer-treatment efficacy (lowering of anthracycline dose and/or lowering of cardiotoxicity) that may be achievable with embodiments of the invention.
As another approach of estimating possible effective dosages for bithionol and/or bithionol sulfoxide in embodiments of the invention, the inventor has used enzyme inhibition data obtained by his own testing (
Bithionol and bithionol sulfoxide have been shown by the inventor to be noncompetitive inhibitors against both coenzyme and carbonyl substrates, with Ki values in the low micromolar range (below 10 μM). These preferred compounds have been seen to exhibit inhibition patterns suggestive of binding to multiple enzyme forms, which may mean that increased anthracycline dosages may not overcome the inhibition. Intrinsic protein fluorescence quenching studies have demonstrated that the preferred bithionol and bithionol sulfoxide inhibitors bind to at least the free enzyme and to an enzyme/product binary complex with Kd values similar to the Ki values (See
In use, one or more of the preferred compounds (bithionol, bithionol sulfoxide) may be used in a pharmaceutical composition, which may also comprise one or more of the anthracycline drugs and/or other chemotherapy drugs or other medicines that may be beneficial to the cancer patient. Preferably, the bithionol/bithionol sulfoxide and anthracycline compositions are given at levels that produce the desired anti-cancer effects without the cardiotoxicity side effects. Therefore, the relative compositions may be changed for different anthracyclines and/or for different patients and/or for different cancers. The methods include treatment of, or treatment of side effects, for all cancers for which anthracyclines are used.
Several analogs of 4-benzoylpyridine were laboratory tested as possible inhibitors for carbonyl reductase, with only three of the analogs tested showing inhibitor behavior. Only two of the inhibitors (bithionol sulfoxide and bithionol) exhibited a low IC50, meaning that only bithionol sulfoxide and bithionol were capable, at low concentrations, in reducing the enzyme activity rate to 50% of that in the absence of the inhibitor. See FIGS. 4A-D for those tested which showed no inhibition (benzyl sulfoxide, phenyl sulfoxide, 4-chlorophenyl sulfoxide, and bis(4-hydroxphenyl)methane), and see FIGS. 5A-C for those that showed at least some inhibition (4,4′-thiodiphenol, bithionol sulfoxide, and bithionol).
Bithionol sulfoxide was shown, in the inventor's testing, to be a non-competitive inhibitor against both a carbonyl substrate (in these examples, menadione) and NADPH, in tests using subsaturating fixed substrate. See
In the inventor's testing, inhibition patterns were seen to differ between bithionol and bithionol sulfoxide, as illustrated in
As illustrated in
From the above inhibition and protein fluorescence testing, both bithionol and bithionol sulfoxide were seen to bind to multiple enzyme forms, as illustrated in
Embodiments of the invention therefore include a pharmaceutical composition comprising at least one anthracycline compound and bithionol or bithionol sulfoxide or a mixture thereof. The inventor envisions that there may be analogs or derivatives of bithionol and/or bithionol sulfoxide that also may be effective in compositions and methods of the invention. The compositions may include, for example, anthracycline compounds selected from the group consisting of adriamycin/doxorubicin, daunorubicin/daunomycin, epirubicin, idarubicin, and a mixture of two or more thereof.
While the preferred patients are humans, animals may also benefit from the compositions and methods. Embodiments of the invented method may be for preventing or treating cardiotoxicity associated with anthracycline cancer chemotherapy in a mammal in need thereof, wherein the method comprises administering to the mammal a composition comprising an effective amount of a pharmaceutical composition comprising at least one anthracycline compound and at least one compound or mixture selected from the group consisting of bithionol, bithionol sulfoxide, a mixture of bithionol or bithionol sulfoxide, an analog of bithionol, an analog of bithionol sulfoxide, a derivative of bithionol, a derivative of bithionol sulfoxide, and mixtures thereof. Examples of anthracycline compounds include adriamycin/doxorubicin, daunorubicin/daunomycin, epirubicin, idarubicin, and a mixture of two or more thereof. Effective amounts of said bithionol; bithionol; and mixtures, analogs, derivatives thereof (that is, both amount per weight of the patient and the amount relative to the dose of anthracycline being used) will be determined by methods known to those of skill in the art, using information available from previous clinical use of bithionol in the human body or in animals for liver fluke treatment, and/or from clinical studies using a dose starting point such as may be calculated from laboratory enzyme inhibition data (such as the above-estimated doses calculated by the inventor using data from the testing represented by
Instead of, or in addition to, administering a pharmaceutical composition including both anthracycline(s) and bithionol and/or bithionol sulfoxide, separate pharmaceutical compositions may be used. For example, methods may include preventing or treating a disease or condition associated with carbonyl reductase in a mammal in need thereof by administering to the mammal a first pharmaceutical composition comprising at least one anthracycline compound; and also administering to the mammal a second pharmaceutical composition comprising bithionol or bithionol sulfoxide, or a mixture thereof. The first and second pharmaceutical compositions may be administered at the same time, or may be administered at nearly the same time (for example, within 15 minutes or less), or preferably within a few hours of each other (for example, within 2 hours or less). It may be beneficial to treat the patient with bithionol and/or bithionol sulfoxide prior to anthracycline therapy (for example, two hours or less prior to anthracycline treatment), to block carbonyl reductase before administration of the anthracycline drug(s).
Thus, it may be said that the preferred composition of bithionol, bithionol sulfoxide, and/or derivatives or analogs thereof, may be administered to a human (or other mammal) in a pharmaceutical composition also comprising at least one anthracycline compound, or may be administered separately from the at least one anthracycline compound either at the same as the anthracycline(s), or any different time found to be effective for inhibiting formation of the anthracycline metabolites.
Although this invention has been described above with reference to particular means, materials, steps, and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the broad scope of the following claims.
This application claims priority of Provisional Application No. 60/776,269, filed Feb. 24, 2006, and entitled “Inhibitors Of Carbonyl Reductase For Treatment Using Anthracyclines”, which is hereby incorporated by reference.
Some activities related to this invention were conducted with support by the United States National Institute of Health, #NIH/P20RR16454.
Number | Date | Country | |
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60776269 | Feb 2006 | US |