Cell-cycle specificity of sulforaphane-mediated apoptosis in Jurkat T-leukemia cells.

Sulforaphane (SFN) is an isothiocyanate that is present in widely consumed vegetables. Previous studies have shown that SFN is effective in preventing carcinogenesis induced by carcinogens in rodents. Recently it was found that SFN could also inhibit cell proliferation and induce apoptosis in several tumor cell lines. In the present study, the possible cell-cycle specificity of SFN-mediated apoptosis was investigated. Cells were synchronized by thymidine block. Analysis of the cell-cycle and apoptosis induction was performed using flow cytometry. Flow cytometric assessment of the extent of apoptosis in cells synchronized by thymidine block revealed that cells were most sensitive to SFN in the G1 phase, less sensitive in the G2/M phase and least sensitive during the S phase. These findings suggest that cell vulnerability to SFN-mediated apoptosis is subject to regulation by cell-cycle-dependent mechanisms.