JPS6361929B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on the following formula The present invention relates to a novel antitumor agent containing ascofuranone as an active ingredient. Ascofuranone is known as an isoprenoid antibiotic produced by a strain of filamentous fungus, Ascoquita vissiae. Regarding the biological activity of ascofuranone, Sawada et al. and Hosokawa et al. reported its serum lipid-lowering effect (Journal.
of Antibiotics, Vol. 26, p. 681, 1973 and Japan Journal of Pharmacology.
(see Vol. 25, p. 35, 1975), but nothing was known about its antitumor effects. During a series of studies on antitumor agents, the present inventors discovered that ascofuranone exhibits remarkable preventive and therapeutic effects on malignant tumors. Conventional non-specific immunostimulants such as BCG, Corynebacterium parvum, OK-432, lentinan, levamisole, and PSK are administered alone to BDF ₁ or CDF ₁ mice transplanted with L-1210 leukemia cells. However, it does not show antitumor activity. On the other hand, ascofuranone can save a certain percentage of mice from tumor death and completely cure them by administering it alone one week or more before transplanting L-1210 leukemia cells. In addition, ascofuranone was administered once a day starting 24 hours after L-1210 leukemia cell transplantation.
When administered twice for 7 to 10 days, a significant survival effect was observed. Unlike L-1210 leukemia, mouse Ehrlichi's ascites carcinoma is one of the typical tumors that can be transplanted regardless of the strain of the mouse and causes tumor death. It also shows remarkable therapeutic and preventive effects. That is, by simply administering ascofuranone once a day, three times every other day, starting 7 days before cancer cell transplantation, the host's lifespan was significantly prolonged, and about half of the mice were completely cured. In addition, Ehrlichi cancer cells were transplanted intraperitoneally,
After 24 hours, administration of ascofuranone once a day for 5 consecutive days significantly prolonged the survival of the mice, with 1/4 to 1/3 of the mice surviving for more than 50 days and being completely cured. Furthermore, when ascofuranone was administered before and after tumor implantation in combination, 70-90% of the mice escaped tumor death and survived for more than 50 days. As described above, the preventive and therapeutic effects of ascofuranone against cancer are extremely unique and unprecedented in conventional anticancer agents or nonspecific immunostimulants. Many conventional anticancer drugs have their main point of action on nucleic acids, inhibiting nucleic acid synthesis and causing deoxyribonucleic acid (DNA) decay. Therefore, its action is not specific to cancer cells, and it also shows strong toxicity to tissue cells that actively divide and proliferate. This often causes side effects such as atrophy of the spleen and thymus, which are organs responsible for the immune system, and a decrease in white blood cells. The mechanism of action of ascofuranone was investigated in cultured cells L-
When examined using 5178Y, the concentration that completely inhibited cell division was 25 μg/ml or higher. This concentration is quite high compared to other anticancer drugs, and it is virtually impossible to think that ascofuranone directly acts on cancer cells to kill them. Furthermore, when examining the effect of ascofuranone on DNA and ribonucleic acid (RNA) synthesis, it was found that ascofuranone is a precursor of
It hardly inhibited incorporation into DNA and RNA. Therefore, unlike conventional anticancer drugs, this drug is thought to have no effect on nucleic acid synthesis. Nucleic acid synthesis inhibitors are known to often exhibit carcinogenic and mutagenic properties, but ascofuranone does not have the effect of promoting reversion in Salmonella typhi and E. coli mutant strains. Also L-5178Y
In experiments on incorporation of radioactive L-leucine into proteins in cells, experiments on incorporation of amino acids into proteins using a cell-free protein synthesis system obtained from L-5178Y, and experiments on incorporation of radioactive acetic acid into lipids.
Ascofuranone did not show any trend of action. Combining the above results, it is certain that the mechanism of action of ascofuranone's anticancer and cancer preventive effects is not the nucleic acid synthesis inhibition effect often seen in conventional anticancer drugs, but the detailed mechanism is still unclear. It has not been. Furthermore, since ascofuranone shows a marked suppressive effect even when administered before tumor transplantation, it is presumed that it also has some effect on the immune system. Continuous oral administration of ascofuranone to rats causes significant enlargement of the thymus gland, which is an organ responsible for immunity, and enlargement of the spleen. This thymus enlargement effect is specific to ascofuranone and is not observed in conventional immunostimulants, and is thought to be somehow related to the therapeutic and preventive effects on L-1210 leukemia. Since it is known that 99% of thymus lymphocytes are composed of T cells, it is presumed that the thymus hypertrophy effect of ascofuranone is based on the hyperfunction of T cells. The acute toxicity LD50 value of ascofuranone in rats and mice is 10 g/Kg or more when administered orally, and 2 g/Kg or more when administered intraperitoneally, so the toxicity is extremely low. Therefore, ascofuranone is useful as a highly safe antitumor agent for humans and animals. Although ascofuranone may be used alone, it is usually preferable to mix it with a suspending agent, excipient, or other auxiliary agent to prepare a dosage form suitable for parenteral and oral administration. Preferred formulations include, for example, injections, powders, granules, tablets, sugar-coated tablets, pills, capsules, and suppositories. These preparations can be manufactured by conventional methods using, for example, the following excipients or auxiliaries. Lactose, sucrose, various starches, glucose, cellulose, methylcellulose, carboxymethylcellulose, magnesium stearate, lauric sulfate, talc, vegetable oil, octyldecyl triglyceride, various polysorbates, polyethylene glycol, lecithin, and these A mixture of two or more types. Preparations for oral administration preferably contain the active ingredient in an amount of 10 to 55% by weight, suppositories to 1 to 50% by weight, and injections to 1 to 20% by weight. The dosage of the antitumor agent of the present invention varies depending on the type of cancer, symptoms, etc., but generally, for example, 1 to 100 mg/Kg per day for injection, 1 to 500 mg/Kg for oral administration, and 1 to 500 mg/Kg per day for oral administration. The case is 1 to 50 mg/Kg. Formulation Example 1 Add 10 parts of ascofuranone to 90 parts of octyldecyl triglyceride and dissolve by heating, then add 5 parts of egg lecithin and mix well. This mixture is added to 395 parts of physiological saline with vigorous stirring to emulsify. This emulsion is treated with ultrasonic waves to further refine the oil droplets, and then filled into ampoules. The above operations are performed under sterile conditions. Formulation example 2 100 parts of well-ground ascofuranone and 210 parts of lactose
1 part, 72 parts of crystalline cellulose, 14 parts of corn starch, and 4 parts of magnesium stearate were added, mixed well, and compressed into tablets with a diameter of 8 mm and a weight of 200 mg using a tablet machine. Experimental Example 1 In the following examples, experiments were conducted by raising mice under conditions of ad libitum access to feed (standard feed, CE-2 manufactured by CLEA Japan or CF-1 manufactured by Oriental Yeast) and tap water. 300 to 150 mg/Kg of ascofuranone was intraperitoneally administered to 4-week-old BDF ₁ female mice (6 mice per group). Since ascofuranone is insoluble in water, it was suspended in a 1% tragacanth gum solution and ground into fine particles using a glass homogenizer.An equal amount of 1% tragacanth gum solution was administered to the control group. DBA/9 days after administration
L-1210 leukemia cells transplanted into mouse lineage 2
¹⁰⁴ mice were implanted intraperitoneally, and the survival days of the mice were examined. The results are shown in Table 1. The numbers in parentheses in the table indicate the number of mice, 1
In the case of animals, it was omitted. Moreover, T/C indicates the percentage of the average survival days of the ascofuranone-administered group and the control group.

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[Table] Experimental Example 2 4-week-old BDF ₁ female mice (10 mice per group) were given
Ascofuranone suspended in 1% gum tragacanth solution
300 mg/Kg was administered intraperitoneally, and a 1% gum tragacanth solution was administered to the control group. L-1210 10 days after administration
10 ³ leukemia cells were subcutaneously transplanted into the left inguinal region, and 24 hours later, 300 mg/Kg of ascofuranone suspended in 1% gum tragacanth solution was intraperitoneally administered once.
The control group received gum tragacanth solution. The results are shown in Table 2. All mice in the control group developed subcutaneous nodular masses at the transplant site, and the average survival time was 13.6 ± 1.65 days, whereas the average survival time in the ascofuranone-treated group was 13.6 ± 1.65 days. The number of days was 24.0±19.00 days, and 2 out of 10 animals survived for more than 60 days and were completely cured.

[Table] Experimental Example 3 Five-week-old CDF ₁ female mice (6 mice per group) were given
¹⁰⁵ L-1210 leukemia cells were intraperitoneally transplanted, and ascofuranone suspended in distilled water containing 0.05% Tween 80 was administered once a day for 7 consecutive days starting 24 hours after transplantation.
400, 200, 100 and 50 mg/Kg were administered intraperitoneally, and distilled water containing 0.05% Tween 80 was administered to the control group. The results are shown in Table 3, and a significant survival effect was observed with administration of 400 to 50 mg/Kg of ascofuranone.

[Table] Experimental Example 4 0.5 to 4-week-old ddY male mice (7 mice per group)
Ascofuranone suspended in % Tween 80 once a day
The control group received an equal amount of 0.5% Tween 80 intraperitoneally. 6 × 10 ⁶ Ehrrich ascites carcinoma cells on the 7th day after the first administration.
The specimen was implanted intraperitoneally. This amount of transplantation is extremely large, and conventional immunostimulants are ineffective.
Furthermore, mice in the ascofuranone pre- and post-administration groups had
In addition to the above three administrations, ascofuranone was intraperitoneally administered three times every other day starting the day after cancer cell transplantation. The results are shown in Table 4. All of the mice in the control group developed ascites cancer and died, whereas a marked survival effect was observed in the ascofuranone pre-administration group, with 3 out of 7 mice dying. The animal survived for more than 50 days and was completely cured.

[Table] Experimental Example 5 6 × 10 ⁵ Ehrlitsu ascites carcinoma cells were intraperitoneally transplanted into 5-week-old ddY male mice (8 mice per group).
Starting 24 hours after transplantation, ascofuranone suspended in 1% Tween 80 was intraperitoneally administered once a day for 5 consecutive days. The results are shown in Table 5. All mice in the control group died from the tumor, while two out of eight mice in the ascofuranone 200 mg/Kg administration group survived for more than 50 days and were completely cured.

[Table] Experimental Example 6 2×10 ⁶ Ehrlitsu ascites carcinoma cells were subcutaneously placed in the left inguinal region of 5-week-old ddY male mice (10 mice per group).
24 hours after transplantation, ascofuranone suspended in 1% Tween 80 was intraperitoneally administered once a day for 7 consecutive days. Control group received an equal amount of 1% Tween
Gave 80. All mice were sacrificed by ether anesthesia 14 days after cancer cell implantation, and tumors were excised and weighed. The results are shown in Table 6.
Tumor growth was strongly suppressed by ascofuranone administration.

[Table] Experimental Example 7 5-week-old BALB/C male mice (10 mice per group)
300 to 150 mg/Kg of ascofuranone suspended in 0.5% gum tragacanth solution was administered intraperitoneally once,
Ten days after administration, 5 x 10 ⁵ MethA fibrosarcoma cells were transplanted intraperitoneally. The result is the 7th
As shown in the table, a single dose of ascofuranone 10 days before tumor cell transplantation resulted in complete cure in 50% of patients in the high-dose group and 20% in the low-dose group.

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Claims (1)

[Claims] 1. An antitumor agent containing ascofuranone as an active ingredient.