Effects of etoposide (VP-16) on the survival and progression of cultured HeLa S3 cells through the cell cycle.

Abstract

The survival of cultured HeLa S3 cells and their progression through the cell cycle after exposure to Etoposide (VP-16) were studied. The dose survival curve of exponentially growing cells was of a biphasic nature; the curve had an exponential slope starting from a small shoulder, and finally attained a plateau against increasing concentrations of the drug. Throughout the cell cycle, VP-16 exerted its main killing activity on cells in the late S and G2 phases, whereas cells in the G1 phase were resistant to the drug. By using a low concentration of VP-16, which allowed 85% of the treated cells to survive, it was found that the inhibition of the cell progression by the drug was greatest in the late S and G2 phases.