Abstract: Objective To observe the effect of 1α,25(OH)2D3 on gastric carcinoma cell proliferation and cell cycle progression and to investigate its possible mechanism．Methods Two gastric cancer cell lines BGC-823 and SGC-7901 were treated with 1α,25(OH)2D3 in a dose dependent manner. Cell proliferation was determined by methyl thiazolyl tetrazolium MTT assay; the cell cycle changes were detected by using flow cytometry; the expression of genes of P21, cyclinD1, cyclinE1 and CDK6 related to the cell cycle was analyzed by RT-PCR. Results 1α,25(OH) 2D3 significantly inhibited two gastric cancer cell lines proliferation in a dose dependent fashion, gastric cancer cells treated with 1α,25(OH) 2D3 caused significantly cell cycle arrest at G1 phase; RT-qPCR showed that 1α,25(OH)2D3 significantly increased P21 mRNA, and attenuated cyclinD1, cyclinE1, CDK6 mRNA expression in BGC-823, SGC-7901 cells(P<0.01). Conclusion 1α,25(OH)2D3 inhibited BGC-823, SGC-7901 cell proliferation and induced cell cycle arrest in G1 phase. The mechanism for the anti-proliferative and cell cycle arrest is probably related to overexpression of P21, down-regulated expression of cyclinD1, cyclinE1, CDK6.

Key words: gastric cancer, 1α,25(OH)2D3, cell proliferation, cell cycle