1α,25-Dihydroxycholecalciferol increases the expression of vascular endothelial growth factor in C3H10T1/2 mouse embryo fibroblasts

Abstract

Evidence suggests that biologically active vitamin D, 1,25- dihydroxycholecalciferol [1,25(OH)2D3], may inhibit carcinogenesis. Because angiogenesis is crucial to carcinogenesis, 1,25(OH) 2D3 regulation of proangiogenic vascular endothelial growth factor (VEGF) secretion was investigated in cellular models for multistage carcinogenesis. Conditioned media from 1,25(OH)2D 3-treated C3H10T1/2 mouse fibroblasts and their Harvey ras-oncogene transfected counterparts (rasneo11a cells) induced human umbilical vein endothelial cell (HUVEC) proliferation (1.3 and 0.3 times, respectively, P < 0.05), suggesting that 1,25(OH)2D3 altered the angiogenic phenotype of the cells. Although rasneo11a cells secreted less VEGF than C3H10T1/2 cells (97%, P < 0.005), 1,25(OH)2D3 induced C3H10T1/2 and rasneo11a cells to secrete 2 and 3 times, respectively, more VEGF than controls (P < 0.05). Similar effects on VEGF release occurred after 1,25(OH)2D3 treatment of MCF10A and MCF10Aras cells, a human breast epithelial cell model for multistage carcinogenesis. In C3H10T1/2 cells, 1,25(OH)2D3 activated the VEGF promoter in a dose-dependent (5-100 nmol/L) manner (maximum 60%) and all doses induced VEGF secretion (P < 0.05). 1,25(OH)2D3 induced VEGF mRNA expression (∼50%) from 2 through 24 h; VEGF release was significantly increased at 8 h and sustained for 24 h. VEGF mRNA expression and release declined as C3H10T1/2 cells grew more confluent, whereas the magnitude of 1,25(OH)2D3-stimulated changes in VEGF was greater in confluent (3.3 times RNA; 3.5 times release) than in subconfluent (50% RNA; 100% release) cultures (P < 0.05). Thus, 1,25(OH)2D3 increases VEGF secretion, and in C3H10T1/2 cells, this is likely through activation of the VEGF promoter and induction of gene expression. These data contribute to understanding the role 1,25(OH)2D3 plays in regulation of angiogenesis in normal compared with disease states.