Deoxynybomycin is a selective anti-tumor agent inducing apoptosis and inhibiting topoisomerase I.

Deoxynybomycin was identified as an inducer of p21the/WAF1 gene following screening using a reporter, p21/luciferase. The present study examined its anti-proliferative effect on human tumor cell lines. Deoxynybomycin selectively inhibited growth of human osteoblastic sarcoma Saos-2, gastric cancer TMK-1, and monocytic leukemia THP-1 cells, but did not affect survival of normal human fibroblasts at doses up to 5 microg/ml. Results from an assay system using a panel of 39 human cancer cell lines indicated that deoxynybomycin has selective cytotoxic activity against lung carcinoma cell lines. Deoxynybomycin induced apoptosis in Saos-2, TMK-1, and THP-1 cells as revealed by DNA fragmentation and TUNEL assays. It inhibited topoisomerase I but not topoisomerase II. These results suggest that deoxynybomycin may be useful in cancer chemotherapy.