CXC‐chemokine/CXCR2 biological axis promotes angiogenesis in vitro and in vivo in pancreatic cancer

Abstract Angiogenesis is essential for tumor growth and metastasis. Although ELR + ‐CXC‐chemokines and their corresponding receptor, CXC‐receptor 2 (CXCR2), are known mediators of angiogenesis, little is known about their role in pancreatic cancer (PaCa). The aim of our study was to determine the role of ELR + ‐CXC‐chemokine/CXCR2 biological axis in promoting PaCa angiogenesis. We prospectively collected secretin‐stimulated exocrine pancreatic secretions (SSEPS) from normal individuals (NP) and PaCa patients. We showed that summed concentrations of ELR + ‐CXC‐chemokines in SSEPS from PaCa patients were significantly higher than in those from NP ( p = 0.002). We measured ELR + ‐CXC‐chemokine levels in supernatants from multiple PaCa cell lines and confirmed that BxPC‐3, Colo‐357 and Panc‐28 had significantly higher expression compared with an immortalized human pancreatic ductal epithelial (HPDE) cell line. After confirming lack of autocrine effects of ELR + ‐CXC‐chemokines on PaCa cells (due to absence of CXCR2 expression), we investigated paracrine effects of these chemokines on human umbilical vein endothelial cells (HUVEC). Both recombinant ELR + ‐CXC‐chemokines and co‐culturing with BxPC‐3 significantly enhanced proliferation, invasion, and tube formation of HUVEC ( p < 0.05). These biological effects were significantly inhibited by treatment with a neutralizing antibody against CXCR2 (anti‐CXCR2 Ab) ( p < 0.05). Finally, anti‐CXCR2 Ab significantly reduced tumor volume ( p < 0.05), Ki‐67 proliferation index ( p = 0.043) and Factor VIII + microvessel density ( p = 0.004) in an orthotopic nude mouse PaCa model. Our results show that ELR + ‐CXC‐chemokines promote PaCa tumor‐associated angiogenesis through CXCR2, suggesting that CXCR2 is an anti‐angiogenic target in PaCa. © 2009 UICC