1,25-Dihydroxyvitamin D3 suppresses exportin expression in human promyelocytic leukemia HL-60 cells.

The active form of vitamin D3, 1alpha,25-dihydroxyvitamin D3 (DVD), is a potent inducer of cell differentiation and inhibits proliferation of cells such as human promyelocytic leukemia HL-60 cells. In the present study, we examined the effects of DVD on the expression of exportin-1 and exportin-t, which play essential roles in the transport of mRNA and tRNA, respectively. The results of reverse transcription-polymerase chain reaction and quantitative real-time polymerase chain reaction indicated that DVD down-regulated the gene expression of these exportins. Western blotting revealed the decreased production of these proteins in DVD-treated cells. Thus, the present findings of decreased expression of exportin-1 and exportin-t induced by DVD can be correlated to inhibition of the proliferation of HL-60 cells.