CXCR4 and CXCR7 signaling promotes tumor progression and obesity-associated epithelial-mesenchymal transition in prostate cancer cells.

Obesity is associated with increased prostate cancer (PCa) progression and higher mortality, however, the mechanism(s) remain still unclear. Here, we investigated signaling by the ASC-secreted chemokine CXCL12 in a mouse allograft model of PCa and in HiMyc mice in the context of diet-induced obesity. Treatment of mice with CXCR4 antagonist inhibited CXCL12-induced signaling pathways, tumor growth and EMT in HMVP2 allograft tumors. Similar results were obtained following prostate epithelium-specific deletion of CXCR4 in HiMyc mice. We also show that CXCR4 signaling regulates expression of JMJD2A histone demethylase and histone methylation which is modulated by AMD3100. Importantly, treatment with a CXCR7 antagonist also inhibited allograft tumor growth and EMT. The current results demonstrate that both CXCR4 and CXCR7 play an important role in cancer progression and establish CXCL12 signaling pathways, activated in obesity, as potential targets for PCa intervention. In addition, other factors secreted by ASCs, may also contribute to cancer aggressiveness in obesity.