Vitamin D receptor expression is required for growth modulation by 1α, 25-dihydroxyvitamin D3 in the human prostatic carcinoma cell line ALVA-31

TE Hedlund, KA Moffatt, GJ Miller - The Journal of Steroid Biochemistry and …, 1996 - Elsevier
TE Hedlund, KA Moffatt, GJ Miller
The Journal of Steroid Biochemistry and Molecular Biology, 1996Elsevier
Epidemiological data suggest that vitamin D3, obtained from dietary sources and sunlight
exposure, protects against mortality from prostate cancer (PC). In agreement with this, the
most active vitamin D metabolite 1α, 25-dihydroxyvitamin D3 [1, 25 (OH) 2 D3] regulates the
growth and differentiation of several human PC cell lines. Both genomic and non-genomic
signalling pathways for 1, 25 (OH) 2 D3 have been reported, although the mechanism of
action in PC cells has not been defined. We now provide data supporting an active role for …
Epidemiological data suggest that vitamin D3, obtained from dietary sources and sunlight exposure, protects against mortality from prostate cancer (PC). In agreement with this, the most active vitamin D metabolite 1α,25-dihydroxyvitamin D3 [1,25(OH)2 D3] regulates the growth and differentiation of several human PC cell lines. Both genomic and non-genomic signalling pathways for 1,25(OH)2 D3 have been reported, although the mechanism of action in PC cells has not been defined. We now provide data supporting an active role for the nuclear vitamin D receptor (VDR) in mediating the growth-inhibitory effects of 1,25(OH)2 D3 on these cells. In the VDR-rich cell line ALVA-31, the observed changes in growth by 1,25(OH)2 D3 are preceded by significant changes in VDR mRNA expression. In contrast, the cell line JCA-1, containing few VDRs, fails to show both early changes in VDR gene expression and later changes in growth with 1,25(OH)2 D3. To assess the role of the VDR more directly, transfection studies were pursued. ALVA-31 cells were stably transfected with an antisense VDR cDNA construct in an attempt to reduce VDR expression. Antisense mRNA expression among clones was associated with: (a) reduced or abolished sensitivity to the effects of 1,25(OH)2 D3 on growth; (b) decreased numbers of VDRs per cell, as measured by radiolabelled-ligand binding; and (c) a lack of induction of the VDR-regulated enzyme 24-hydroxylase in response to 1,25(OH)2 D3. From these studies we conclude that the antiproliferative effects of 1,25(OH)2 D3 require expression of the nuclear VDR in this system.
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