PrLZ regulates EMT and invasion in prostate cancer via the TGF‐β1/p‐smad2/miR‐200 family/ZEB1 axis

Abstract Background Prostate leucine zipper (PrLZ) is a prostate‐specific protein, and our previous study demonstrated that PrLZ enhances the malignant progression of prostate cancer (Pca). However, the roles of PrLZ in epithelial to mesenchymal transition (EMT) remain unknown. Methods Quantitative real‐time PCR (qRT‐PCR), immunohistochemical (IHC) staining, hematoxylin‐eosin (HE) staining, and western blotting were used to analyze the expression of protein and genes level in human PCa cell lines. Invasion assay was used to examine the effect of PrLZ, miR‐200a, miR‐200b, miR‐200c, miR‐141, miR‐429, miR‐205, and ZEB1 on PCa cell line invasion in vitro. Prostate cancer metastasis animal model was designed to assess the effect of PrLZ on PCa cell line invasion in vivo. Results We proved that high PrLZ expression initiates EMT, which was shown by the downregulation of E‐cadherin and upregulation of vimentin in PC‐3/PrLZ and ARCaP‐E/PrLZ cells. Mechanistic analysis revealed that PrLZ regulates EMT by activating TGF‐β1/p‐smad2 signaling and further inhibiting the expression of miR‐200 family members, which negatively regulates ZEB1 expression and causes EMT in Pca. Moreover, using two of orthotopic mouse model and tail vein injection of human prostate cancer cells mouse model, we observed that PC‐3/PrLZ cells led to the development of distant organ metastases in vivo. Conclusions Our results show the mechanism by which PrLZ regulates EMT and metastasis and suggest that PrLZ may be a potential therapeutic target for Pca metastasis.