Retinoic Acid Induces a G 1 Cell Cycle Block in HeLa Cells 1

Abstract

Summary

Evidence is presented that retinoic acid-induced anchorage dependent growth of HeLa cells is cell cycle dependent. Spinner cultures of retinoic acid-inhibited cells were blocked in the G₁ phase and this block was reversed by simultaneous removal of retinoic acid and attachment of the cells to a plastic tissue culture surface. Studies with a synchronized cell population demonstrated that the retinoic acid had to be added during or before late S phase if the cells were to be blocked in the subsequent G₁ phase. These findings are consistent with the hypothesis that vitamin A establishes normal growth controls to some transformed cells.