Patent Application
20050288378
Cancer, a leading fatal disease, features an abnormal mass of malignant tissue resulting from excessive cell division. Cancer cells proliferate in defiance of normal restraints on cell growth, and invade and colonize territories normally reserved for other cells.
Modes of cancer therapy include chemotherapy, surgery, radiation, and combinations of these treatments. Chemotherapy typically involves use of one or more compounds that inhibit cancer cell growth. While many cancer chemotherapeutic agents have been developed, there remains a need for more effective chemotherapy.
This invention is based on a surprising discovery that Irisquinone A (IqA) significantly enhances efficacy of a chemotherapeutic agent in inhibiting the growth of cancer cells.
Thus, this invention relates to a method of treating cancer, the method including administering to a subject in need thereof an effective amount of a cancer chemotherapeutic agent and an effective amount of a benzoquinone compound of formula I:
in which R1 is alkyl or alkenyl; each of R2 and R3 is H, alkyl, aryl, alkoxy, or hydroxy; and R4 is H, alkyl, or aryl. The cancer mentioned above is esophagus carcinoma, gastric adenocarcinoma, prostate carcinoma, or lung cancer.
Referring to formula I, one subset of the benzoquinone compounds feature that R1 is
Another subset of the benzoquinone compounds feature that R1 is (CH2)16CH3. Still another subset of the benzoquinone compounds feature that each of R2 and R3 is H and R4 is CH3.
Set forth below are two exemplary benzoquinone compounds that can be used to practice the above methods:
The chemotherapeutic agent used in the above method is a drug that can be used to treat cancer. Examples include, but are not limited to, cisplatin, mitomycin C, bleomycin, topotecan, irinotecan, docetaxel, paclitaxel, podophyllotoxin, vincristin, plicamycin, daunorubicin, dactinomycin, adriamycin, 5-fluorouracil, hormones, hormone antagonists, and cytokines (e.g., interleukin-2 and transforming growth factor β). In one embodiment, the chemotherapeutic agent is cisplatin.
The above-mentioned method may further include applying radiation to a subject, after the subject is administered with the benzoquinone compound. The radiation used in this method may be ionizing radiation and non-ionizing radiation. It can be radiation with gamma ray, X-ray, neutrons, electrons, alpha particles, beta particles, ultraviolet rays, visible light, infrared light, microwave, and radio waves.
Also within the scope of this invention is a composition containing a benzoquinone compound, a chemotherapeutic agent, and a pharmaceutically acceptable carrier for treating cancer, as well as the use of such a composition for the manufacture of a medicament for treating cancer.
The term “alkyl” refers to a straight or branched hydrocarbon, containing 1-20 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, and t-butyl. The term “alkoxy” refers to an —O-alkyl radical.
The term “alkenyl” refers to a straight or branched hydrocarbon having one or more carbon-carbon double bonds. The alkenyl can contain 1-20 carbon atoms.
The term “aryl” refers to a 6-carbon monocyclic, 10-carbon bicyclic, 14-carbon tricyclic aromatic ring system wherein each ring may have 1 to 4 substituents. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, and anthracenyl.
Alkyl, alkoxy, alkenyl, and aryl mentioned herein include both substituted and unsubstituted moieties. Examples of substituents include, but are not limited to, halo, hydroxyl, amino, cyano, nitro, mercapto, alkoxycarbonyl, amido, carboxy, alkanesulfonyl, alkylcarbonyl, carbamido, carbamyl, carboxyl, thioureido, thiocyanato, sulfonamido, alkyl, alkenyl, alkynyl, alkyloxy, aryl, heteroaryl, cyclyl, and heterocyclyl, in which the alkyl, alkenyl, alkynyl, alkyloxy, aryl, heteroaryl, cyclyl, and heterocyclyl may be further substituted.
Details of several embodiments of the invention are set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description, and also from the claims.
The above-described benzoquinone compound enhances the efficacy of a chemotherapeutic agent in treating cancer, when they are both administered to a subject. Consequently, a lower dose of the chemotherapeutic agent is required in order to obtain a desired therapeutic effect, thereby resulting in fewer side effects. Thus, an aspect of this invention relates to a method of treating cancer by administering to a subject in need thereof an effective amount of one or more of the above-described compounds and an effective amount of a chemotherapeutic agent. The term “an effective amount” refers to the amount of the active agent that is required to confer the intended therapeutic effect in the subject. Effective amounts may vary, as recognized by those skilled in the art, depending on route of administration, excipient usage, and the possibility of co-usage with other agents. The term “treating” refers to administering the above-described benzoquinone compounds and the chemotherapeutic agent to a subject that has cancer, or has a symptom of cancer, or has a predisposition toward cancer, with the purpose to cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve, or affect the cancer, the symptoms of the cancer, or the predisposition toward the cancer.
Some of the benzoquinone compounds used to practice this method are naturally occurring and can be isolated from natural sources. For example, IqA and IqB can be isolated from the seed coating of Iris pallasii Fisch. var. chinensis Fisch. and the seed oil of Iris pseudacorus L. Others can be synthesized by methods well known in the art or prepared from the naturally-occurring compounds via simple transformations. The chemicals used in the isolation and synthesis of the benzoquinone compounds may include, for example, solvents, reagents, catalysts, and protecting group and deprotecting group reagents. The isolation and synthesis may also include steps to add or remove suitable protecting groups in order to ultimately obtain desired benzoquinone compounds. Synthetic chemistry transformations and protecting group methodologies (protection and deprotection) useful in synthesizing applicable benzoquinone compounds are known in the art and include, for example, those described in R. Larock, Comprehensive Organic Transformations, VCH Publishers (1989); T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3rd Ed., John Wiley and Sons (1999); L. Fieser and M. Fieser, Fieser and Fieser's Reagents for Organic Synthesis, John Wiley and Sons (1994); and L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995) and subsequent editions thereof.
The benzoquinone compounds mentioned above may contain one or more double bonds. Thus, they may occur as cis- or trans-isomeric forms. Such isomeric forms are contemplated.
Chemotherapeutic agents that can be used to practice this method include cisplatin, mitomycin C, bleomycin, topotecan, irinotecan, docetaxel, paclitaxel, podophyllotoxin, vincristin, plicamycin, daunorubicin, dactinomycin, adriamycin, or 5-fluorouracil. Other chemotherapeutic agents can also be used, e.g., cytokines, hormones, or hormone antagonists. See, e.g., Isselbacher et al., Harrison's Principles of Internal Medicine 13th, McGraw-Hill, 1994. As well known in the art, a chemotherapeutic agent can be selected based on, for example, the type of neoplasm being treated, the expression of one or more markers by cancer, and the age and general health of the subject to be treated. All the above-mentioned chemotherapeutic agents are commercially available.
To practice this method, a benzoquinone compound and a chemotherapeutic agent can be applied at the same time or at different times. They can be administered orally, parenterally, by inhalation spray, or via an implanted reservoir. The term “parenteral” as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intraarticular, intraarterial, intrasynovial, intrasternal, intrathecal, intralesional and intracranial injection or infusion techniques.
An oral composition can be any orally acceptable dosage form including, but not limited to, tablets, capsules, emulsions and aqueous suspensions, dispersions and solutions. Commonly used carriers for tablets include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added to tablets. For oral administration in a capsule form, useful diluents include lactose and dried corn starch. When aqueous suspensions or emulsions are administered orally, the active ingredient can be suspended or dissolved in an oily phase combined with emulsifying or suspending agents. If desired, certain sweetening, flavoring, or coloring agents can be added.
A sterile injectable composition (e.g., aqueous or oleaginous suspension) can be formulated according to techniques known in the art using suitable dispersing or wetting agents (such as, for example, Tween 80) and suspending agents. The sterile injectable preparation can also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that can be employed are mannitol, water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium (e.g., synthetic mono- or di-glycerides). Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions can also contain a long-chain alcohol diluent or dispersant, or carboxymethyl cellulose or similar dispersing agents.
An inhalation composition can be prepared according to techniques well known in the art of pharmaceutical formulation and can be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other solubilizing or dispersing agents known in the art.
A topical composition can be formulated in form of oil, cream, lotion, ointment and the like. Suitable carriers for the composition include vegetable or mineral oils, white petrolatum (white soft paraffin), branched chain fats or oils, animal fats and high molecular weight alcohols (greater than C12). The preferred carriers are those in which the active ingredient is soluble. Emulsifiers, stabilizers, humectants and antioxidants may also be included as well as agents imparting color or fragrance, if desired. Additionally, transdermal penetration enhancers may be employed in these topical formulations. Examples of such enhancers can be found in U.S. Pat. Nos. 3,989,816 and 4,444,762. Creams are preferably formulated from a mixture of mineral oil, self-emulsifying beeswax and water in which mixture the active ingredient, dissolved in a small amount of an oil, such as almond oil, is admixed. An example of such a cream is one which includes about 40 parts water, about 20 parts beeswax, about 40 parts mineral oil and about 1 part almond oil. Ointments may be formulated by mixing a solution of the active ingredient in a vegetable oil, such as almond oil, with warm soft paraffin and allowing the mixture to cool. An example of such an ointment is one which includes about 30% almond and about 70% white soft paraffin by weight.
A carrier in a pharmaceutical composition must be “acceptable” in the sense that it is compatible with active ingredients of the formulation (and preferably, capable of stabilizing it) and not deleterious to the subject to be treated. For example, solubilizing agents, such as cyclodextrins (which form specific, more soluble complexes with one or more of active compounds of the extract), can be utilized as pharmaceutical excipients for delivery of the active ingredients. Examples of other carriers include colloidal silicon dioxide, magnesium stearate, cellulose, sodium lauryl sulfate, and D&C Yellow # 10.
The above-mentioned method may further include applying radiation to the subject to be treated. The radiation used in this method may be ionizing radiation or non-ionizing radiation. Ionizing radiation has sufficient energy to interact with an atom and remove electrons from their orbits, causing the atom to become charged or “ionized.” It includes radiation with gamma ray, X-ray, neutrons, electrons, alpha particles, and beta particles. Non-ionizing radiation is electromagnetic radiation that does not have sufficient energy to remove electrons from their orbits. It includes radiation with ultraviolet rays, visible light, infrared light, microwave, and radio waves. The radiation is applied to the subject after administration of the benzoquinone compound. It may be applied before, during, or after administration of the chemotherapeutic agent.
Suitable in vitro assays can be used to preliminarily evaluate the efficacy of the combination of one or more of the above-described compound and a chemotherapeutic agent in inhibiting proliferation of cancer cells. The combination can further be examined for its efficacy in treating cancer by in vivo assays. For example, the combination can be administered to an animal (e.g., a mouse model) having cancer and its therapeutic effects are then accessed. Based on the results, an appropriate dosage range and administration route can also be determined. In a similar manner, the in vitro and in vivo assays can also be used to evaluate efficacy of the combination in the presence of radiation.
Without further elaboration, it is believed that the above description has adequately enabled the present invention. The following specific examples are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. All of the publications, including patents, cited herein are hereby incorporated by reference in their entirety.
An in vitro assay was conducted to evaluate the efficacy of a combination of cisplatin and IqA in inhibiting proliferation of cancer cells.
The human tumor cell lines, i.e., Eca-109 (esophagus carcinoma cell line), BGC-823 (gastric adenocarcinoma cell line), DU145 (prostate carcinoma cell line), and SPC-A1 (lung cancer cell line), were purchased from the Cell Bank of Shanghai Institute of Cell Biology, Chinese Academy of Sciences, and cultured in Iscove's Modified Dulbecco's Medium (IMDM) containing 10% fetal bovine serum (FBS) in an incubator at 37° C. under 5% CO2. The cells of 70˜80% confluence were trypsinized, resuspended in IMDM medium containing 10% FBS at 1×105 cells/ml, and seeded in 96-well plates (100 μl in each well). The plates were incubated at 37° C. under 5% CO2 overnight.
IqA and cisplatin were provided by Shandong Xinhua Pharmaceutical Co. Ltd. and Qilu Pharmaceutical Ltd., respectively. IqA, cisplatin, and a combination of IqA and cisplatin in a weight ratio of 1:1 were each dissolved in phosphate-buffered saline (PBS) and diluted with the cell growth medium to give a series of solutions of different concentrations. The diluted solutions (10 μl) were added to wells containing cancer cells. The final concentrations for each of IqA, cisplatin, and the combination solutions in the wells were 100, 30, 10, 3, 1, and 0.3 μg/ml. 10 μl of dimethyl sulfoxide (DMSO) was added to wells containing human cancer cells and these wells were used as control. Wells to which no IqA, cisplatin, and DMSO were added were used as the background. The plates were then incubated at 37° C. under 5% CO2 for 48 hrs.
10 μl of 5 mg/ml 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was each added to all wells except for the background wells. After being incubated for additional 3-4 hrs, the plates were spun at 1000 rpm for 15 minutes and the supernatants were carefully removed by vacuum. The cells were washed with 150 μl of PBS.
150 μl of DMSO was added to each well. The plates were placed on a shaker at 150 rpm for 15 minutes to dissolve the precipitate in the wells. Absorbance was measured at 492 nm using a microplate reader. Experiments were done in triplicate.
A software program, XLfit (ID Business Solutions), was used to calculate the concentrations required to reach 10, 20, . . . 90% inhibition (i.e., IC10, IC20, . . . IC90) on each cancer cell line. Compared to IqA alone and cisplatin alone, the combination of IqA and cisplatin had unexpectedly low IC10, IC20, . . . IC90 values against esophagus carcinoma, gastric adenocarcinoma, and prostate carcinoma. The results show that the combination was more effective in inhibiting these cancer cells than IqA alone or cisplatin alone.
Combination Indexes (CIs) were calculated according to the method described in the literature (Bertino J. et al. Chemotherapy: Synergism and Antagonism, Encyclopedia of Cancer, 1996, Academic Press, Inc.). A CI represents the combination effect, such as, synergism, antagonism or addition of two or more drugs. When the CI is lower than 1, the combination effect is synergistic; when the CI is equal to 1, the combination effect is additive; and when the CI is higher than 1, the combination effect is antagonistic. For all four cancer cell lines, the CI values of the combination were each lower than 1. In other words, the combination of 1:1 cisplatin and IqA showed synergistic effect in inhibiting the proliferation of these cancer cells.
All of the features disclosed in this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features.
From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Thus, other embodiments are also within the claims.
Pursuant to 35 USC § 119(e), this application claims priority to U.S. Provisional Applications 60/581,663 and 60/634,238, filed Jun. 21, 2004 and Dec. 7, 2004, respectively. The contents of both provisional applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60581663 | Jun 2004 | US | |
| 60634238 | Dec 2004 | US |
