Arrest effect of diallyl disulfide on cell cycle in human nasopharyngeal cancer CNE2 cells

Objective: To investigate the arrest effect of diallyl disulfide (DADS) in the cell cycle of human nasopharyngeal carcinoma CNE2 cell line and its molecular mechanism. Methods: The growth inhibition of CNE2 cell line was measured by MTT assay and cell counting. Phase distribution of cell cycle was analyzed by flow cytometry. The expression of p21^WAF1 was determined by Western blotting analysis. Results: MTT assay showed that DADS inhibited growth of CNE2 cells significantly and exhibited a dose dependent modal. Adding 90 μmol/L, 140 μmol/L, 240 μmol/L and 400 μmol/L DADS for 48 hours suppressed CNE2 growth by 3.3%, 12.9%, 28.3% and 56.9%, respectively. Cell counting showed that average doubling time retarded from 24.5 hours in normal cultured CNE2 cells to 93.1 hours in 400 μmol/L DADS experimented CNE2 cells (P < 0.05). Flow cytometry analysis revealed that CNE2 cells treated with increasing quantities of DADS increased the percentage of cells in the G ₀/G₁ phase. Western blotting analysis suggested that p21^WAF1 was up-regulated when treated with DADS in a dose dependent manner. Conclusion: The antiproliferation property of diallyl disulfide (DADS) in cultured human nasopharyngeal carcinoma CNE2 cell line relates to its ability to arrest G₀/G₁ through over-expression of p21 ^WAF1.