title: [Inhibition of the growth of a murine transplantable tumor, colon 26, by the prostaglandin synthetase inhibitor, indomethacin].
abstract: Cancer cells and macrophages produce large amounts of prostaglandin (PG) E2, which suppress cellular immune r action in tumor-bearing individuals. These findings raised a possibility that PG synthetase inhibitor can restore the immune reactivity against tumors. The anti-tumor activity of indomethacin, a potent PG synthetase inhibitor, by oral administration of 0.002% water solution as drinking water from the day 0 or 7 days after tumor transplantation was investigated in BALB/c or CDF1 (BALB/c X DBA/2) mice implanted subcutaneously with colon carcinoma 26 (10(6) cells) as a series of model studies for cancer treatment. The treatment with indomethacin substantially 1) inhibited the tumor growth, 2) prolonged the survival time, 3) caused a regression and disappearance of tumor with some cured mice and 4) reduced the levels of PGE2 and ornithine decarboxylase activity, a first rate limiting enzyme of polyamine synthesis in tumor tissue. Those anti-tumor activities were 5) reduced by a concomitant administration of PGE2 and 6) increased by a combined administration of an immunopotentiating agent, Picibanil (OK-432). The results indicate that indomethacin inhibited the synthesis of PGE2 in the tumor tissue, which suppress the non-specific cellular immune reaction against tumor cells, resulting in the regression and disappearance of tumor. PG synthetase inhibitor may be effective also against human cancer.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003110:Colonic Neoplasms / Q000473:pathology / Q000628:therapy*; D016861:Cyclooxygenase Inhibitors; D015232:Dinoprostone; D007213:Indomethacin / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D010844:Picibanil / Q000627:therapeutic use; D011458:Prostaglandins E / Q000096:biosynthesis / Q000494:pharmacology
chemical_list: D016861:Cyclooxygenase Inhibitors; D011458:Prostaglandins E; D010844:Picibanil; D015232:Dinoprostone; D007213:Indomethacin