JPWO1996032101A1 - Cancer metastasis inhibitor - Google Patents

Abstract

(57) [Summary] The present invention relates to a compound represented by the following general formula (I): (wherein _R1 , _R2 , _R3 and _R4 are the same or different and each represent a hydrogen atom, a hydroxyl group, or a trimethylsilyl group, or _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted with a lower alkyl group; X represents a -COCH=C(OH)-, -NHCO-, or -CONH- group; provided that when _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted with a lower alkyl group, X is a -COCH=C(OH)- or -CONH- group), use of the benzoic acid derivative for producing the cancer metastasis inhibitor, and a method for inhibiting cancer metastasis, which comprises administering an effective amount of the benzoic acid derivative to a mammal for the inhibition of cancer metastasis. The benzoic acid derivative of general formula (I) has an extremely good inhibitory effect on cancer metastasis.

Description

Detailed Description of the Invention Technical Field : Cancer Metastasis Inhibitor The present invention relates to a cancer metastasis inhibitor that significantly inhibits the metastasis of cancer cells.

BACKGROUND ART In recent years, cancer treatment has made revolutionary progress, and in particular, the improvement in the success rate of primary cancer removal by surgery or radiation therapy has contributed greatly to the progress of such cancer treatment. However, even if the primary cancer is completely removed, there are many cases where patients die from recurrence due to metastasis of the cancer, and there is a limit to how far surgery or radiation therapy can completely prevent cancer metastasis, and metastasis to distant cells remains a direct or indirect cause of cancer death.

Currently, the following hematogenous mechanism of cancer metastasis is postulated: (1) cancer cells proliferate in the primary tumor, (2) new blood vessels are formed, (3) malignant cancer cells invade the newly formed blood vessels and enter the bloodstream, (4) circulate throughout the body, (5) reach the target site, (6) invade the extravasation, (7) proliferate in the target organ, and (8) form metastatic lesions.

Many chemotherapeutic agents (antitumor drugs) are known today. These drugs are used as drugs acting on mechanism (1) above, exhibiting direct growth inhibition and cytocidal effects on cancer cells, accompanied by tumor shrinkage. However, they are far from satisfactory drugs because they cause various side effects, including bone marrow toxicity, and have little effect on other metastatic processes.

In general, cancer metastasis inhibitors not only prevent the metastasis of cancer cells, but also aim to inhibit the growth of already formed micrometastases and the development of metastasis and recurrence. Therefore, their evaluation is considered to be completely different from that of conventional antitumor agents, which seek to shrink tumors through cytotoxicity. Therefore, new types of drugs that take the metastatic process into consideration, have fewer side effects, and can be administered over a long period of time, are highly valued as metastasis inhibitors, and such drugs are in demand.

For these reasons, there is growing recognition that preventing metastasis is an important issue that must be overcome in cancer treatment, and clinical trials of cancer metastasis inhibitors are being conducted in the United States, the United Kingdom, and other countries. Furthermore, in recent years, genes thought to be involved in cancer metastasis and invasion have been identified one after another, and it has been reported that retinoids and all-trans-retinoic acid can inhibit the expression of these genes in a concentration-dependent manner, thereby suppressing metastasis and invasion. However, the effect is insufficient, and an effective cancer metastasis inhibitor has yet to be discovered.

DISCLOSURE OF THE INVENTION In view of the current situation as described above, the present inventors have investigated from various perspectives the pharmacological effects of specific types of benzoic acid derivatives, which have not previously been known to have an inhibitory effect on cancer metastasis, and as a result have found that these compounds have an extremely effective inhibitory effect on cancer metastasis, thereby completing the present invention.

That is, the present invention provides a compound represented by the following general formula (I): (wherein _R1 , _R2 , _R3 and _R4 are the same or different and each represent a hydrogen atom, a hydroxyl group or a trimethylsilyl group, or _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted by a lower alkyl group; X represents a -COCH=C(OH)- group, a -NHCO- group or a -CONH- group, provided that when _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted by a lower alkyl group, X is a -COCH=C(OH)- group or a -CONH- group.)

The present invention also provides use of a benzoic acid derivative represented by the above general formula (I) for producing an agent for inhibiting cancer metastasis.

Furthermore, the present invention provides a method for inhibiting cancer metastasis, which comprises administering an effective amount of the benzoic acid derivative represented by the above general formula (I) to a mammal for the purpose of inhibiting cancer metastasis.

In the benzoic acid derivative represented by the general formula (I), examples of the lower alkyl group include linear or branched alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, and hexyl, and preferably linear or branched alkyl groups having 1 to 4 carbon atoms. Examples of the tetramethylene group substituted with a lower alkyl group include tetramethylene groups having 1 to 8 lower alkyl groups as substituents, preferably tetramethylene groups having 2 to 4 lower alkyl groups, and particularly preferred examples include 1,4-dimethyltetramethylene, 1,1,4-trimethylenetetramethylene, 1,4,4-trimethyltetramethylene, and 1,1,4,4-tetramethyltetramethylene.

The benzoic acid derivatives represented by the general formula (I) are known compounds described in Japanese Patent Application Laid-Open Nos. 62-215581, 1-249783, and 2-247185, and can be prepared based on the descriptions in the above publications. These compounds are known as cancer therapeutic agents and agents for inducing differentiation of cancer cells, but are not known to have an inhibitory effect on cancer metastasis.

Specific examples of the compound represented by general formula (I) above include 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-3-hydroxy-2-naphthalenyl)-1-propenyl]benzoic acid (hereinafter referred to as Compound Re80), 4-[3,5-bis(trimethylsilyl)phenylcarbamoyl]benzoic acid (hereinafter referred to as Compound Am55S), and 4-[3,5-bis(trimethylsilyl)phenylcarboxamido]benzoic acid (hereinafter referred to as Compound Am555S), which are represented by the following structural formulas.

Of the above compounds, for example, compound Re80 can be produced according to the methods described in JP-A No. 62-215581, compound Am55S can be produced according to the methods described in JP-A No. 1-249783, and compound Am55 5S can be produced according to the methods described in JP-A No. 2-247185.

The cancer metastasis inhibitor of the present invention contains the benzoic acid derivative represented by the above general formula (I) as an active ingredient, and may be administered alone or in admixture with a pharmaceutically acceptable carrier, prepared into various dosage unit forms.

In either case, these are prepared into pharmaceutical compositions using appropriate pharmaceutically acceptable carriers in a conventional manner. Examples of carriers used here include various types commonly used in conventional pharmaceutical preparations, such as diluents or excipients, such as fillers, extenders, binders, disintegrants, surfactants, and lubricants.

When the cancer metastasis inhibitor of the present invention is used for the purpose of inhibiting cancer metastasis in mammals, including humans, the dosage form is not particularly limited and can be appropriately selected depending on the purpose of treatment. Specific examples include tablets, pills, powders, liquids, suspensions, emulsions, granules, capsules, suppositories, injections, ointments, patches, etc.

When forming tablets, carriers such as lactose, sucrose, sodium chloride, glucose, urea, starch, calcium carbonate, kaolin, and crystalline cellulose, excipients such as silicic acid, water, ethanol, propanol, simple syrup, glucose solution, starch solution, gelatin solution, carboxymethylcellulose, shellac, methylcellulose, potassium phosphate, and polyvinylpyrrolidone, binders such as dry starch, sodium alginate, powdered agar, powdered laminarin, sodium bicarbonate, and calcium carbonate, are used. Disintegrants such as ammonium, polyoxyethylene sorbitan fatty acid esters, sodium lauryl sulfate, stearate monoglyceride, starch, and lactose; disintegrants such as sucrose, stearic acid, cocoa butter, and hydrogenated oil; absorption enhancers such as quaternary ammonium bases and sodium lauryl sulfate; humectants such as glycerin and starch; adsorbents such as starch, lactose, kaolin, bentonite, and colloidal silicic acid; and lubricants such as purified talc, stearates, boric acid powder, and polyethylene glycol. Furthermore, tablets can be coated with conventional coatings, such as sugar-coated tablets, gelatin-coated tablets, enteric-coated tablets, film-coated tablets, double-layered tablets, and multi-layered tablets, if desired.

When forming into pills, carriers that can be used include excipients such as glucose, lactose, starch, cacao butter, hardened vegetable oil, kaolin, and talc; binders such as powdered gum arabic, powdered tragacanth, gelatin, and ethanol; and disintegrants such as laminaran and agar.

Capsules are prepared by mixing the benzoic acid derivative of general formula (I) with the various carriers exemplified above and filling the mixture into hard gelatin capsules, soft capsules, etc.

When forming into suppositories, carriers such as polyethylene glycol, cocoa butter, esters of higher alcohols, gelatin, and semi-synthetic glycerides can be used.

When prepared as an injection, the solution, emulsion, or suspension is preferably sterilized and isotonic with blood. When preparing these formulations, diluents such as water, lactic acid solution, ethyl alcohol, propylene glycol, ethoxylated isostearyl alcohol, polyoxylated isostearyl alcohol, polyoxyethylene sorbitan fatty acid esters, etc. may be used. In this case, sufficient amounts of salt, glucose, or glycerin to prepare an isotonic solution may be added to the pharmaceutical formulation. Conventional solubilizers, buffers, soothing agents, etc. may also be added.

When preparing ointments such as pastes, creams, and gels, diluents such as white petrolatum, paraffin, glycerin, cellulose derivatives, polyethylene glycol, silicone, bentonite, etc. may be used.

Furthermore, each of the above preparations may contain coloring agents, preservatives, perfumes, flavoring agents, sweeteners, and other pharmaceuticals as needed.

The amount of the benzoic acid derivative represented by general formula (I) contained in the cancer metastasis inhibitor of the present invention is not particularly limited and may be selected appropriately, but is generally about 1 to 70% by weight of the formulation.

The method of administration of the cancer metastasis inhibitor of the present invention is not particularly limited and is determined depending on the dosage form, the patient's age, sex, and other conditions, the severity of the patient's symptoms, etc. For example, tablets, pills, powders, liquids, suspensions, emulsions, granules, and capsules are administered orally. Suppositories are administered rectally. Injections are administered intravenously, either alone or mixed with standard fluids such as glucose and amino acids, and may also be administered alone, intraarterially, intramuscularly, intradermally, subcutaneously, or intraperitoneally, as needed. Ointments are applied to the skin, oral mucosa, etc.

The dosage of the active ingredient of the cancer metastasis inhibitor of the present invention can be selected appropriately depending on the method of administration, the patient's age, sex, and other conditions, the severity of the disease, etc. Generally, the amount of the benzoic acid derivative represented by general formula (I) is set to approximately 0.1 to 100 mg/kg/day, preferably approximately 0.5 to 50 mg/kg/day. These cancer metastasis inhibitors of the present invention can be administered once a day or in divided doses approximately 2 to 4 times a day.

There are no particular limitations on the type of cancer metastasis that can be inhibited by administering the cancer metastasis inhibitor of the present invention, and examples thereof include liver metastasis, lung metastasis, lymph node metastasis, etc.

The benzoic acid derivatives represented by the above general formula (I) have an extremely effective inhibitory effect on cancer metastasis, and compositions containing the benzoic acid derivatives as active ingredients are useful as agents for inhibiting cancer metastasis.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be explained below with reference to pharmacological test examples and formulation examples, but the present invention is not limited to these.

Pharmacological Test Example 1: Effect in a Liver Metastasis Model The inhibitory effect of compounds Re80, Am55S, and Am555S on cancer metastasis was measured.

<Experimental Method> KM12 L4 (human colon cancer), TMK-1 (human gastric cancer), and A549 (human lung cancer) cells were transplanted into the spleens of SPF BALB/c-nu/nu male mice (7 weeks old) at a concentration of 1 x ¹⁰ cells/mouse, and liver metastasis was investigated using these models.

The specific experiment was performed using a modified version of the method of Morikawa et al. (Cancer Research, 48 , 1943-1948, (1988)). Specifically, cells cultured in vitro were harvested with 0.25% trypsin-0.02% EDTA or 0.02% EDTA and washed with physiological phosphate buffer. The cells were counted and diluted to 1 x ¹⁰ cells/50 μl. Next, under anesthesia with 30 mg/kg Nembutal, the left abdominal cavity of the mouse was opened, the spleen was removed, and 50 μl of the cell suspension (1 x ¹⁰ cells/50 μl) prepared above was transplanted into the spleen using a syringe equipped with a 28-gauge needle. After leaving the mixture for 2 minutes, two blood vessels leading to the spleen were ligated with ligaclips, the spleen was excised, and the abdominal opening was sutured with a Kiffer suture. Compounds Re80, Am55S, and Am555S, which are the active ingredients of the cancer metastasis inhibitor of the present invention, were orally administered as a 5% ethanol/olive oil suspension or a 0.5% carboxymethylcellulose/0.5% Tween 80 (registered trademark, manufactured by Nacalai Tesque) suspension starting the day after transplantation. Each treatment was administered for 5 consecutive days, followed by 2 days of rest, for a total of 3 courses. Evaluation was based on the survival rate compared to the vehicle control group. The survival rate of all-tran s-retinoic acid (ATRA), which is known to have cancer metastasis inhibitory effects, was also determined using the same experimental method. The results are shown in Table 1.

As shown in Table 1, each of the compounds Re80, Am55S, and Am555S, which are the active ingredients of the cancer metastasis inhibitor of the present invention, significantly extended survival time, with the maximum values converted into survival rates based on the control group being 50% for Re80, 42% for Am55S, and 71% for Am555S. Furthermore, when compared with all-trans-retinoic acid (ATRA), which is known to have cancer metastasis inhibitory activity, the maximum survival rates of each of the above compounds were high, with a particularly significant difference being observed for Re80 and Am555S. Therefore, it was confirmed that each of the compounds Re80, Am55S, and Am555S, which are the active ingredients of the cancer metastasis inhibitor of the present invention, are effective in inhibiting cancer metastasis.

Pharmacological Test Example 2: Tumor Growth Inhibitory Effect <Experimental Method> 4-1ST (human gastric cancer) and LC-6 (human lung cancer) tumor cells, which had been subcutaneously propagated in advance, were cut into 2 mm x 2 mm x 2 mm pieces and transplanted subcutaneously into the right dorsal region of male SPF BALB/c-nu/nu mice (7 weeks old) using a transplant needle. The estimated tumor volume was calculated using the following formula. When the estimated tumor volume reached 100-250 ^mm3 , the mice were divided into groups and administered various concentrations of Am555S, 5-fluorouracil (5-FU), and cisplatin (CDDP). The administration method selected was the one considered most preferable for each drug. Specifically, Am555S was administered orally for 5 consecutive days followed by 3 cycles with a 2-day rest period, 5-FU was administered via tail vein for 5 consecutive days, and CDDP was administered as a single dose via tail vein. Three weeks after the start of administration, the mice were sacrificed, and the tumor growth inhibition rate was calculated from the tumor weight using an untreated group as a control to determine the tumor cell growth inhibition effect. The results are shown in Table 2.

Estimated tumor volume = major axis × minor axis ² / 2 (mm ³ ) As shown in Table 2, compared with 5-FU and CDDP, which are currently widely used as antitumor agents due to their tumor growth inhibitory effects, Am555S, the active ingredient of the cancer metastasis inhibitor of the present invention, had a significantly lower tumor growth inhibitory rate and no tumor growth inhibition was observed.

Toxicity Test Six SPF ICR male mice (5 weeks old) were used in each group. Mice in the Re80, Am55S, and Am555S groups were orally administered 2 mg/kg/day of Re80, 640 mg/kg/day of Am55S, or 16 mg/kg/day of Am555S for three consecutive weeks. No deaths occurred in any of the compound groups. Furthermore, no significant side effects were observed.

Formulation Example 1 Tablets Compound Re80 40 mg Starch 100 mg Magnesium stearate 15 mg Lactose 45 mg Total 200 mg Tablets weighing 200 mg each were prepared using the above formulation according to standard procedures.

Formulation Example 2: Granules Compound Am55S 200 mg Lactose 340 mg Cornstarch 450 mg Hydroxypropyl methylcellulose 10 mg Total 1000 mg Granules were prepared using the above blend ratios according to standard procedures.

Formulation Example 3: Capsules Compound Am555S 100 mg Lactose 170 mg Microcrystalline cellulose 77 mg Magnesium stearate 3 mg Total 350 mg Capsules were prepared using the above blend ratios according to standard procedures.

Formulation Example 4: Injection Compound Am555S 200 mg Distilled water for injection (as needed) 5 ml per ampoule An injection was prepared using the above formulation according to standard procedures.

Formulation Example 5: Suppositories Compound Am555S 100 mg Witepsol W-35 1400 mg (Registered Trademark, manufactured by Dynamite Nobel) 1500 mg per suppository Suppositories were prepared using the above blend ratios according to standard procedures.

───────────────────────────────────────────────────── (Note) This publication is based on the publication published internationally by the International Bureau of Patents (WIPO). The effect of the international publication of the Japanese patent application (Japanese utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act) and is unrelated to this publication.

Claims (12)

[Claims] 1. General formula (I) (wherein _R1 , _R2 , _R3 and _R4 are the same or different and each represent a hydrogen atom, a hydroxyl group, or a trimethylsilyl group, or _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted by a lower alkyl group; X represents a group -COCH=C(OH)-, a group -NHCO-, or a group -CONH-; provided that when _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted by a lower alkyl group, X is a group -COCH=C(OH)- or a group -CONH-). 2. The cancer metastasis inhibitor according to claim 1, wherein the benzoic acid derivative represented by general formula (I) is 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-3-hydroxy-2-naphthalenyl)-1-propenyl]benzoic acid. 3. The agent for inhibiting cancer metastasis according to claim 1, wherein the benzoic acid derivative represented by general formula (I) is 4-[3,5-bis(trimethylsilyl)phenylcarbamoyl]benzoic acid. 4. The cancer metastasis inhibitor according to claim 1, wherein the benzoic acid derivative represented by general formula (I) is 4-[3,5-bis(trimethylsilyl)phenylcarboxamido]benzoic acid. 5. General formula (I) for producing a cancer metastasis inhibitor (wherein _R1 , _R2 , _R3 and _R4 are the same or different and each represent a hydrogen atom, a hydroxyl group, or a trimethylsilyl group, or _R3 and _R4 are bonded to each other to form a tetramethylene group substituted by a lower alkyl group; X is a -COCH=C(OH)- group, a -NHCO- group, or a -CONH- group, provided that when _R3 and _R4 are bonded to each other to form a tetramethylene group substituted by a lower alkyl group, X is a -COCH=C(OH)- group or a -CONH- group). 6. Use of the benzoic acid derivative according to claim 5, wherein the benzoic acid derivative represented by general formula (I) is 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-3-hydroxy-2-naphthalenyl)-1-propenyl]benzoic acid. 7. Use of the benzoic acid derivative according to claim 5, wherein the benzoic acid derivative represented by general formula (I) is 4-[3,5-bis(trimethylsilyl)phenylcarbamoyl]benzoic acid. 8. Use of the benzoic acid derivative according to claim 5, wherein the benzoic acid derivative represented by general formula (I) is 4-[3,5-bis(trimethylsilyl)phenylcarboxamido]benzoic acid. 9. General formula (I) (wherein _R1 , _R2 , _R3 and _R4 are the same or different and each represent a hydrogen atom, a hydroxyl group, or a trimethylsilyl group, or _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted by a lower alkyl group; X represents a -COCH=C(OH)- group, a -NHCO- group, or a -CONH- group, provided that when _R3 and _R4 are bonded to each other to represent a tetramethylene group substituted by a lower alkyl group, X represents a -COCH=C(OH)- group or a -CONH- group) to a mammal for the purpose of inhibiting cancer metastasis, the method comprising administering an effective amount of a benzoic acid derivative represented by the following formula to a mammal for the purpose of inhibiting cancer metastasis. 10. The method for inhibiting cancer metastasis according to claim 9, wherein the benzoic acid derivative represented by general formula (I) is 4-[1-hydroxy-3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-3-hydroxy-2-naphthalenyl)-1-propenyl]benzoic acid. 11. The method for inhibiting cancer metastasis according to claim 9, wherein the benzoic acid derivative represented by general formula (I) is 4-[3,5-bis(trimethylsilyl)phenylcarbamoyl]benzoic acid. 12. The method for inhibiting cancer metastasis according to claim 9, wherein the benzoic acid derivative represented by general formula (I) is 4-[3,5-bis(trimethylsilyl)phenylcarboxamido]benzoic acid.