MODE OF ACTION OF A NEW ANTI-TUMOR ANTIBIOTIC, SPORAMYCIN

Sporamycin, an antitumor antibiotic, primarily inhibited DNA synthesis, while RNA and protein synthesis were not significantly affected in [human cervical carcinoma] HeLa S3 cells. The antibiotic also caused strand scission of cellular DNA. The effects were not observed when the cells were incubated at 0.degree. C before washing and subsequently incubated at 37.degree. C. The Tm [melting point] of calf thymus DNA decreased when incubated with sporamycin in vitro. Sporamycin did not affect DNA synthesis in vitro catalyzed by partially purified DNA polymerases .alpha., .beta. and .gamma. derived from [mouse] Ehrlich ascites cells.