Induction of Protein-DNA Complexes in HeLa S3 Cells by KW-2149, a New Derivative of Mitomycin C

KW-2149 is a new water-soluble analogue of mitomycin C which shows a broad spectrum antitumor activity in experimental tumor models including mitomycin C-resistant tumors and is less hematotoxic than mitomycin C. We have found that KW-2149 increases protein-DNA complexes in HeLa S3 cells using the potassium/sodium dodecyl sulfate precipitation method which recovers largely DNA bound covalently to protein but does not precipitate DNA bound noncovalently to proteins. In contrast, no increase of the protein-DNA complexes are shown in cells treated with mitomycin C. Thus, KW-2149 binds covalently with both DNA and protein, and this may mediate for KW-2149 the potent and characteristic antitumor activity compared with mitomycin C.