A new macromolecular antitumor antibiotic, C-1027. III. Antitumor activity

C-1027, a new macromolecular antitumor antibiotic produced by Streptomyces globisporus C-1027, showed extremely potent cytotoxicity toward cultured cancer cells. Compared in terms of IC50 values, antibiotic C-1027 showed much more potent cytotoxicity than doxorubicin, mitomycin C and neocarzinostatin. Spermatogonial assay, a prescreen for anticancer drugs, was highly sensitive for detection of C-1027. At tolerable doses, C-1027 exhibited marked inhibition on a panel of transplantable tumors in mice, which included leukemia L1210, P388, ascites hepatoma H22, sarcoma 180 and melanoma Harding-Passey.