1,25D3 differentially suppresses bladder cancer cell migration and invasion through the induction of miR-101-3p

Metastasis is the major cause of bladder cancer death. 1,25D(3), the active metabolite of vitamin D, has shown anti-metastasis activity in several cancer model systems. However, the role of 1,25D(3) in migration and invasion in bladder cancer is unknown. To investigate whether 1,25D(3) affects migration and invasion, four human bladder cell lines with different reported invasiveness were selected: low-invasive T24 and 253J cells and highly invasive 253J-BV and TCCSUP cells. All of the four bladder cancer cells express endogenous and inducible vitamin D receptor (VDR) as examined by immunoblot analysis. 1,25D(3) had no effect on the proliferation of bladder cancer cells as assessed by MTT assay. In contrast, 1,25D(3) suppressed migration and invasion in the more invasive 253J-BV and TCCSUP cells, but not in the low-invasive 253J and T24 cells using "wound" healing, chemotactic migration and Matrigel-based invasion assays. 1,25D(3) promoted the expression of miR-101-3p and miR-126-3p in 253J-BV cells as examined by qRT-PCR. miR-101-3p inhibitor partially abrogated and pre-miR-101-3p further suppressed the inhibition of 1,25D(3) on migration and invasion in 253J-BV cells. Further, 1,25D(3) enhanced VDR recruitment to the promoter region of miR-101-3p using ChIP-qPCR assay. 1,25D(3) enhanced the promoter activity of miR-101-3p as evaluated by luciferase reporter assay. Taken together, 1,25D(3) suppresses bladder cancer cell migration and invasion in two invasive/migration competent lines but not in two less invasive/motile lines, which is partially through the induction of miR-101-3p expression at the transcriptional level.