Treatment with calcitriol or its analogues may be a potential effective chemotherapy for pancreatic cancer. Vitamin D Receptor (VDR) plays an important role in antitumor. However, the precise function and mechanism of VDR in Pancreatic cancer remain undefined. To address this question, we investigated the effects of calcitriol on PANC-1 cell line with VDR gene silencing or not. We found evidence that calcitriol could induce growth inhibition, block the G1/S transition and result in apoptosis in

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... PANC-1 cell line. But those effects were weakened in the VDR gene silencing group. Caspase-3, p21 and p27 levels were noticeably up-regulated after treatment with calcitriol, while Bax/Bcl-2 ratio changed not obviously. In VDR gene silencing groups, caspase-3 expression was equally up-regulated after treatment with calcitriol, but not obviously; Bax/Bcl-2 ratio declined after treatment with calcitriol; p21 and p27 levels were down-regulated. These results were further confirmed at the mRNA levels. Therefore, our results revealed that calcitriol exerted anticancer effects may be mainly via VDR pathway. The VDR gene expression may have a close relationship with the expression of cycle and apoptosis-related molecules, like caspase-3, p21 and p27. However, further precise antitumor mechanisms of calcitriol still need to be elucidated.