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| Year : 1984 | Volume
: 30
| Issue : 1 | Page : 23-6 |
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The effect of combination of folic acid and anticancer drugs on the growth of sarcoma 180 in mice.
MA Indap, SV Gokhale
Correspondence Address:
M A Indap
How to cite this article:
Indap M A, Gokhale S V. The effect of combination of folic acid and anticancer drugs on the growth of sarcoma 180 in mice. J Postgrad Med 1984;30:23-6
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How to cite this URL:
Indap M A, Gokhale S V. The effect of combination of folic acid and anticancer drugs on the growth of sarcoma 180 in mice. J Postgrad Med [serial online] 1984 [cited 2023 Oct 1 ];30:23-6
Available from: https://www.jpgmonline.com/text.asp?1984/30/1/23/5490 |
Full Text
INTRODUCTION
Malnutrition and wasting are frequently associated with malignancy. Deficiency of vitamins in the diet has been attributed to the incidence of cancer of the stomach, the nasopharynx and the lung. It is increasingly being recognised, however, that the cancer patients may develop a deficiency of a specific nutrient, the nature of which depends on the type of cancer.[2] A low level of serum folic acid activity (SFAA)[7],[8] has been found in leukaemia, malignant lymphoma and carcinoma of head and neck. Low levels of other important vitamins have been reported in some cancer patients.[1],[4],[9]
Folic acid (pteroyl glutamic acid) is a compound made up of pteridine nucleus, p-aminobenzoic acid and glutamic acid. The vitamin is widely distributed in common foods in which it is present in various forms including polyglutamic acid conjugates. Folic acid exists in living tissues in various reduced forms some of which are coenzymes and most of which are derivatives of tetrahydrofolic acid (THF). The coenzymatic derivatives of THF have the function of transferring a "single carbon group" in the biological synthesis of certain metabolites e.g. (1) de novo purine synthesis, (2) pyrimidine nucleotide synthesis, (3) amino acid interconversions, and (4) generation and utilization of formate.
One of the important problems of chemotherapy of tumours appears to be the elaboration of the optimum therapeutic procedures that would help to reduce undesirable effects of the cytotoxic drugs and enhance their effects on tumours. With this aspect in mind, we studied the effects of folic acid administration during anti-tumour drug therapy.
MATERIAL AND METHODS
Anticancer drugs
5-Fluorouracil (5-FU), Mitomycin-C (Biochem Pharmaceutical Industries, Bombay), Methotrexate (MTX) (Lederle Parenterals, Inc., USA), 6-Mercaptopurine (6-MP) (Burroughs Wellcome & Co., Bombay), Vincristine (VCR) (Immu-Kimia Laboratories, Bombay) and Folic acid (BDH, Bombay) were purchased locally.
Tumour
Sarcoma 180 (S180)[3],[10] was maintained in Swiss mice by weekly i.p. passages of ascitic fluid obtained from a 7-day old S180 (ascitic) tumour-bearing animals.
Evaluation of activity
Swiss mice of either sex and 18-22 g in weight were used for anti-tumour testing. The tumour cells were harvested from the peritoneal cavity of animals with a 7-day-old ascitic tumour under aseptic conditions. Each animal received 0.2 ml containing 10[6] cells by subcutaneous route just above the hind leg on the left side. This day was designated as day zero. The animals were randomized in groups of six. The anti-cancer drugs were dissolved in physiological saline or distilled water or 0.2% CMC in saline (suspension). The drugs were injected i.p. on every 4th day (i.e. on days 1, 5, 9)*.
Folic acid was dissolved in 2% sodium bicarbonate and was given prior to the drug administration either by i.p. (31.25 mg/kg) or oral (250, mg/kg) route depending on the schedule of treatment. The control animals received the vehicle. The weights of the animals were recorded on days 1st and 5th and the average body weight difference was calculated.[3] On the 11th day of tumour transplantation, the animals were killed and the tumours were dissected out. Tumour weights were recorded and per cent tumour weight inhibition (TWI %) was determined.
RESULTS
[Table 1] shows the results with FA (250 mg/kg) administered orally 1 hour prior to the anti-cancer drugs (Schedule I). Amongst the five combinations tried, only 5-FU in combination with FA was found to be effective in inhibiting the growth of S180 (solid) tumour. 6-MP itself produced antitumour activity and there was a marginal increase in antitumour activity when it was given with FA. In the remaining three combinations, there was no increase in antitumour activity. The drugs themselves were also found to be inactive against S180 (solid) tumour.
In the other schedules of treatment, FA was administered orally 24 hours prior to the administration of anti-cancer drugs (Schedule ID, i.p. simultaneously with the anti-cancer drugs (Schedule III), and also i.p. 24 hours prior to the anti-cancer drugs (Schedule IV). The anti-cancer drugs were always injected i.p. at the same dosages. The dose of FA in i.p. administration was 31.25 mg/kg, as toxicity was encountered as judged by the weight loss and death of animals[3] at higher doses of FA. In each of the schedules of treatment, only 5-FU in combination with FA was found to be effective. In Schedule III, the increase in antitumour activity was from 52 to 7370 and the remaining combinations failed to show enhanced antitumour activity. Folic acid itself was found to be inactive in all these experiments (data not incorporated). The inactivity of FA has been reported by earlier workers.[10]
DISCUSSION
5-FU in combination with FA when FA was administered simultaneously i.p. or orally 1 hour prior to 5-FU was found to be active. This is explained by the work of Heidelberger and his group.[5] 5-Fluoro-2'-deoxyuridylate (FdUMP), the active phosphorylation form of 5-FU combines with methylene THF and thymidylate synthetase forming a stable complex which prevents the conversion of uridine to thymidine. This is considered as the most important mechanism of action of 5-FU. The 6th carbon of FdUMP is bound covalently to the enzyme with the methylene group covalently linking to the 5-carbon of the nucleotide [Fig. 1]. Excess of folic acid by supplying sufficient amount of methylene THF increases the complex formation and, therefore, improves the efficacy of 5-FU given at the same dose. Our results bear out this fact quite consistently. In earlier studies from this laboratory, we have reported that FA in a properly timed sequence in combination with MTX, 5-FU, and Ara-C increases their antitumour activity against P388, a lymphocytic leukaemia (accepted for publication).[6] It is now proposed to study different schedules of treatment and the dose ratios to find out how the effect of 5-FU can be optimized in the solid (sc) form. The combination of 5-FU and FA will also be tried in patients.
ACKNOWLEDGEMENT
The authors thank Dr. R. Y. Ambaye, Scientific Officer, Chemotherapy Division, for his helpful criticism and valuable suggestions. Thanks are also due to Shri M. R. Joshi for his technical assistance.
References
| 1 | Aksoy, M., Basu, T. K., Brient, J. and Dickerson, J. W. T.: Thiamine status of patients treated with drug combinations containing 5-Fluorouracil. Europ. J. Cancer, 16: 1041-1045, 1980. |
| 2 | Dickerson, J. W. T. and Basu, T. K.: Specific vitamin deficiencies- and their significance in patients with cancer and receiving chemotherapy. In, "Nutrition and Cancer"; Editor: Winick, M., A. Wiley-Interscience Publication, New York, 1977,. pp. 95-104. |
| 3 | Geran, R. I., Greenberg, N. H., MacDonald, M. M., Schumacher, A. M. and Abbott, B. J.: Protocols for screening chemical agents and---natural - products against animal tumours and other biological systems. Cancer Chemother. Rep. (Part 3) 3: 1-103, 1972. |
| 4 | Krasner, IC and Dymock, I. W.: Ascorbic acid deficiency in malignant diseases: A clinical and biochemical study. Brit. J. Cancer, 30: 142-145, 1974. |
| 5 | Langenbach, R. J., Danenberg, P. V. and Heidelberger, C.: Thymidylate synthetase: Mechanism of inhibition by 5-fluoro-2'-deoxyuridylata. Biochem, Biophys. Res. Comm. 48: 1565-1571, 1972. |
| 6 | Parchure, M. A., Ambaye, R. Y. and Gokhale, S. V.: Combination of anticancer agents with folic acid in the treatment of murine leukaemia P388. Accepted for publication in. "Chemotherapy". |
| 7 | Rao, P. B. R., Lagerlof, B., Einhorn, J, and Reizensterin, P.: Low serum folic acid in malignancy. Lancet, I: 1192-1193, 1963. |
| 8 | Rao, P. B. R., Lagerlof, B., Einhorn, J. and Reizensterin, P.: Folic acid activity in leukaemia and cancer. Cancer Res. 25. 221-224, 1965. |
| 9 | Soukop, M. and Calman, K. C.: Thiamine vitamin B1 status in cancer patient-and the effect of 5-fluorouracil therapy. Brit. J, Cancer,. 38: 180, 1978. |
| 10 | Sugiura, K.: Relative sensitivity of the solid and ascites forms of Sarcoma 180 and Ehrlich carcinoma to inhibitory compounds. Ann. N.Y. Acad. Sci., 76: 575-585, 1958. |
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