VDR Suppress Proliferation And Metastasis In RCC Cell Via Regulating The Expression Of TRPV5

Background: Renal cell carcinoma(RCC)is the most common form of kidney tumor with an estimated 65340 new cases diagnosed and 14970 death in 2017 in United States.Despite significant advances have been made in RCC treatment,the prognosis is still poor and mortality rate remains high.Consequently,it is an urgent need to study the molecular mechanisms of proliferation and metastasis in RCC,which may provide new treatment methods.We previously demonstrated that transient receptor potential vanilloid subfamily 5(TRPV5)expression was decreased in renal cell carcinoma(RCC)compared with normal kidney tissues,which correlated with vitamin D receptor(VDR),but further investigations is warranted.The aim of this study is to elucidate whether VDR could regulate the expression of TRPV5 and effect the proliferation and metastasis in RCC.Martial and Methods: VDR expression levels in caki-1 and 786-O cells were measured by RT-PCR and Western blot.We used lentivirus to conduct VDR overexpression and knockdown RCC cells line.Several functional experiments were performed to measure the influence of VDR in cell proliferation,apoptosis,migration and invasion by MTT assay,flow cytometry assay and Transwell assay.RNA-sequence assay was also assessed after VDR overexpression and knockdown in caki-1 cell.TRPV5 expression levels were assessed after VDR overexpression and knockdown in caki-1 cell.The proliferation,migration and invasion of caki-1 cells,which VDR and TRPV5 co-knockdown,were tested compared to VDR knockdown and control caki-1 cells.Results: VDR expression in caki-1 was observed higher compared to 786-O cells.VDR overexpression significantly inhibited cell proliferation,migration and invasion,and promoted apoptosis in RCC cell lines.Whereas,VDR knockdown had the opposite effect.RNA-sequence assay also indicated significantly differentially expressed genes were associated with cell apoptotic,differentiation,proliferation and migration.RT-PCR and western blot analysis showed that VDR knockdown increased TRPV5 expression and VDR overexpression decreased TRPV5 expression in caki-1 cells.Furthermore,knockdown TRPV5 expression suppressed the VDR knockdown-induced change in proliferative,migrate and invasive ability in caki-1 cells.Conclusions: These findings confirmed VDR functions as a tumor suppressor in RCC cells,and suppress the proliferation,migration and invasion of RCC through regulation the expression of TRPV5.