Antiproliferative Effect of 1α,25-dihydroxyvitamin D3 Involves Upregulation of Cyclin-Dependent Kinase Inhibitor p21 in Human Pancreatic Cancer Cells

Background/Aims: The aim of this study was to investigate the effect of 1 alpha,25-dihydroxyvitamin D3 on proliferation of human pancreatic cancer cell lines and to identify related cell cycle regulatory proteins with antiproliferative effects. Methodology: Human pancreatic cancer cell lines SUIT-2 and its four sublines, and Panc-1, AsPC-1, and MiaPaCa-2 were treated with1 alpha,25-dihydroxyvitamin D3. The number of cells was measured by the MTT method, and the cell cycle regulatory proteins were then analyzed by Western blotting. Results: Eight human pancreatic cancer cell lines expressed vitamin D receptor (VDR) mRNA. 1 alpha,25-dihydroxyvitamin D3 inhibited proliferation of SUIT-2 and its sublines. We found p21 to be upregulated after 24 hours in S2-028, the cell line in which proliferation was most inhibited by 1 alpha,25-dihydroxyvitamin D3. Conclusions: 1 alpha,25-dihydroxyvitamin D3 inhibited proliferation of pancreatic cancer cells and is involved in the upregulation of cyclin-dependent kinase inhibitor p21.