IL-6 mediates the signal pathway of JAK-STAT3-VEGF-C promoting growth, invasion and lymphangiogenesis in gastric cancer

Gastric cancer shows the highest invasive and metastasis features, especially lymph metastasis, which is closely associated with poor prognosis of gastric cancer. Although there is evidence that interleukin-6 (IL-6) can promote gastric cancer progression, the underlying specific mechanisms and the mechanisms of gastric cancer lymphangiogenesis are largely unknown. In the present study, we explore whether IL-6 could promote the proliferation and invasion activity of gastric cancer cells, and whether IL-6 mediating VEGF-C production affected the lymphangiogenesis in gastric cancer cells. Our results revealed that IL-6 and its receptors (IL-6 and gp130) are broadly expressed in various gastric cancer cell lines including SGC-7901, MGC, MKN-28 and AGS. Exogenous IL-6 increased the ability of gastric cancer cell proliferation and invasion, which could be weakened by AG490. in addition, exogenous IL-6 promoted the VEGF-C production of gastric cancer cells and the lymphangiogenesis of HDLECs. As we expected, AG490 was able to reduce these effects. Western blot analysis showed that IL-6 increased JKA, STAT3, p-STAT3 and VEGF-C protein levels in the gastric cancer cells. However, the JKA, STAT3, p-STAT3 and VEGF-C protein expression levels were inhibited by AG490. Our data suggested that IL-6 mediates the singnal pathway of JAK-STAT3-VEGF-C promoting the growth, invasion and lymphangiogenesis in gastric cancer. Thus, IL-6 and its related signal pathways may be a promising target for treatment of gastric cancer growth and lymphangiogenesis.