Induction of apoptosis and cell cycle arrest by polyvinylpyrrolidone K-30 and protective effect of alpha-tocopherol.

Polyvinylpyrrolidone is a macromolecular polymer with widespread use in industry as well as in medicine for various purposes. Its effect on cells cultured in vitro, however, has not been fully investigated. To elucidate this issue, we studied the influence of PVP K-30 on cultured HeLa cells. PVP K-30 treatment produced a dose- and time-dependent toxicity to HeLa cells. Cells exposed to PVP K-30 exhibited several morphological features of apoptosis. Gel electrophoresis of DNA from PVP K-30-treated cells showed typical apoptotic ladder. And flow cytometric analysis demonstrated that PVP K-30 induced cell cycle arrest at G2/M phase and the subsequent appearance of sub-G1 population. In addition, it was shown that procaspase-3 was activated in response to PVP K-30 treatment. We also found that alpha-tocopherol efficiently protected HeLa cells from PVP K-30 cytotoxicity. This is the first demonstration that PVP K-30 could induce apoptosis in HeLa cells and cell cycle arrest at G2/M phase, and that PVP K-30 toxicity could be attenuated by alpha-tocopherol.