Improved Analysis of Prostate Cancer: VIM3, ATG7 and P53 Form a Complex and Activate miRNA 371a-3p

It is not possible to differentiate prostate carcinomas sufficiently to ensure that every patient receives the right therapy. New molecular markers are needed. Our objective was to identify a complex consisting of vimentin variant 3 (VIM3), autophagy-related protein 7 (ATG7) and tumor protein p53 (TP53) in prostate cancer cells and its effect on microRNA (miR)-371a-3p.

Prostate cancer cell lines (PC3, DU145, LNCaP) and the benign prostatic hyperplasia cell line BPH-1 were cultured in growth medium for 24 h, then stimulated with endothelin 1 (EDN1) (50 nM) and withaferin A (2 nM) for 24 h. Cell extracts were then analyzed by western blot. The localization of VIM3, ATG7 and TP53 in the nucleus was demonstrated with immunofluorescence staining and complex formation was demonstrated by immunoprecipitation. Cancer cell migration was analyzed with a scratch assay and agarose drop analysis. The binding of the complex to the promoter of pri-miR-371a-3p was analyzed with a non-radioactive electrophoretic mobility shift assay. VIM3 knockdown using small interfering RNA and quantitative real-time polymerase chain reaction for miR-371a-3p were performed.

The complex was present in the nucleus of prostate cancer cells and in the BPH-1 cell line. EDN1 increased the levels of the complex partners and cell migration, whereas withaferin A reduced the levels of the complex partners and migration. The complex bound to the promoter of pri-miR-371a-3p and might be involved in its transcription. Transfection with miR-371a-3p increased migration of prostate cancer cells. VIM3 knockdown reduced miR-371a-3p expression.

The VIM3-ATG7-P53 complex, with its stimulatory effect on miR-371a-3p, may have the potential to be a marker for improved differentiation between prostate carcinomas, allowing tailored therapy.