Exosomal lncAY927529 enhances prostate cancer cell proliferation and invasion through regulating bone microenvironment

Exosomes mediate the interaction between cancer cells and their microenvironment, and play a key role in tumor development. Although exosomes can package lncRNAs to mediate extracellular communication, the role of exosomal lncRNA AY927529 in prostate cancer (PCa) remains unclear. Exosomes were extracted from normal human prostatic epithelial cell lines (BPH-1 and RWPE-1) and PCa cell lines (VCaP and LNCaP, DU145, PC3) by ultrahigh speed centrifugation. Results of Western blot indicated that Alix, HSC70 and TSGl01 protein levels were upregulated in exosomes derived from PCa cells. LncAY927529 level was upregulated in PCa cells and exosomes derived from PCa patient serum and human PCa cells. CCK-8, Transwell and Flow cytometry assays demonstrated that bone marrow stromal cell line (ST2) conditioned medium (ST2-CM), treated with exosomes derived from PCa cells with high lncAY927529 level, promoted proliferation and invasion of PC3 and DU145 cells, and inhibited cell apoptosis. RT-qPCR assay indicated that lncAY927529 level was downregulated in PC3 and DU145 cells, exosomes derived from PCa cells (PCa-Exo) and ST2-CM treated with PCa-Exo with low expression of lncAY927529, and overexpression of lncAY927529 had the opposite results. In addition, Western blot assay showed that the autophagy related protein LC3II level was increased in ST2 cells treated with exosomes derived from DU145 cells with high expression of lncAY927529, and LC3I protein level was decreased. CXCL14 acted as a RNA-binding protein of lncAY927529, and exosome-mediated lncAY927529 positively regulated CXCL14 levels in ST2 cells. In general, exosome-mediated lncAY927529 could promote PCa cell proliferation and invasion by regulating bone microenvironment, suggesting that exosomal lncAY927529 may be a potential molecular diagnostic marker of PCa.