The Differential Expression and Function of the Inflammatory Chemokine Receptor CXCR5 in Benign Prostatic Hyperplasia and Prostate Cancer

Background: Chemokine and chemokine receptors could have played an important role in tumor angiogenesis and distant metastasis. The mechanism of inflammation, expression and function of chemokines and chemokine receptors in benign prostatic hyperplasia (BPH) and prostate cancer (PCa) remain unclear. The purpose of present study is to detect differential expression and function of chemokines and chemokine receptors (CCRs) in BPH and PCa. Methods: BPH-1 and peripheral blood mononuclear cells (PBMCs) were co-cultured in Transwell chambers, and human normal prostate (NP) tissues, BPH tissues and PCa tissues were collected. CCR gene-chips were used to analyze and compare the differential expression of CCRs in BPH-1 cells, BPH-1 cells co-cultured with PBMCs, and LNCaP cells. The differential expression of CCRs was detected and validated using real-time PCR, western blotting and immunofluorescence (IF). The proliferation of LNCaP cells was also investigated after the knockdown CXCR5. Results: Results of gene-chips indicated that there was low or no expression of CCR10, CXCR1, CXCR3 and CXCR5 in BPH-1 cells, whereas the expression of these receptors in BPH-1 cells was increased by PBMCs, and the expression was high in LNCaP cells. Furthermore, real-time PCR and western blotting confirmed the above mentioned results. IF verified no or low expression of CXCR1, CXCR3 and CXCR5 in NP tissues, low or moderate expression in BPH and high expression in PCa. However, CCR10 was not expressed at detectable levels in the three groups. The growth and proliferation of LNCaP cells was markedly inhibited after down-regulation of CXCR5. Conclusions: PCa cells expressed high levels of CCR10, CXCR1, CXCR3 and CXCR5. Although BPH cells did not express these factors, their expression was up-regulated when BPH-1 cells were incubated with inflammatory cells. Finally, down-regulation of CXCR5 inhibited the growth and proliferation of LNCaP cells.