Synthesis and cytotoxic action of 3,5-isoxazolidinediones and 2-isoxazolin-5-ones in murine and human tumors.

The 3,5-isoxazolidinediones and 2-isoxazolin-5-ones demonstrated potent cytotoxicity against the growth of human Tmolt3 T cell leukemia, murine P388 and L1210 leukemias, as well as human HeLa-S3 uterine carcinoma and glioma tumor cell growth. The specificity of the 3,5-isoxazolidinedione and 2-isoxazoline-5-one derivatives as cytotoxic agents varied with the histological type of tumor cell. Selected compounds were active against solid HeLa uterine. KB nasopharynx, skin A431, SW-480 adenocarcinoma, osteosarcoma and glioma growth. Selected compounds demonstrated in vivo antineoplastic activity against Ehrlich ascites carcinoma growth. In L-1210 leukemia cells, the agents blocked DNA and protein synthesis at 25, 50 and 100 microM over 60 min. The agents were effective in reducing rate limiting enzymes in the de novo purine and pyrimidine pathways. In addition they suppressed dihydrofolate reductase and ribonucleoside reductase activities with moderate inhibition of DNA and RNA polymerase activities. DNA itself was not a target of the agents.