Background: Vascular endothelial growth factor (VEGF) is one of the most potent angiogenic growth factors and its expression is correlated with MVD (microvascular density) in malignant tumors, including pancreatic adenocarcinoma. On the other hand, serum interleukin-6 (IL-6) is elevated in many patients with pancreatic cancer in accordance with their disease progression. In this study, we examined whether IL-6 and its receptors have any involvement in the induction of VEGF in pancreatic cancer.
Materials and methods: Two human pancreatic cancer cell lines were examined for the induction of VEGF after treatment with IL-6. Thirty-two pancreatic cancer surgical specimens were stained immunohistochemically with VEGF, IL-6 and IL-6 receptor antibodies.
Results: CFPAC-1 cells expressed IL-6 receptor whereas AsPC-1 cells rarely expressed it. IL-6 treatment induced VEGF expression significantly and dose-dependently in CFPAC-1 cells, while it did not change in AsPC-1 cells. The intensity of VEGF expression in CFPAC-1 also increased time-dependently with IL-6 treatment. In 32 surgical pancreatic cancer tissues, 19 (59%) stained positive for VEGF and 26 (87%) positive for IL-6 receptor beta subunit. The correlation between IL-6 receptors and VEGF was significant (p = 0.0002 and p = 0.0019) while less correlation was seen between IL-6 and VEGF (p = 0.1937).
Conclusion: Our results suggest that IL-6 is likely to take part in VEGF expression in both paracrine and autocrine fashion in pancreatic cancer. Induction of VEGF seems to be regulated by the extent of the IL-6 receptor expression on cancer cells.