Antitumor activity of pyrindamycins A and B.

Abstract

Pyrindamycins A(1) and B(2) exhibited stronger cytotoxic activities than doxorubicin towards murine and human tumor cell lines and especially towards doxorubicin-resistant cells. Pyrindamycins A and B were also active in vivo against P388/ADR, a multidrug-resistant tumor cell line. Intracellular accumulation of pyrindamycins A and B in P388/ADR was the same as in P388. These antibiotics strongly inhibited DNA synthesis compared with RNA or protein synthesis. They showed significant therapeutic effects towards murine leukemia, but not to solid tumors.