Accumulating evidence suggests that TAMs contribute to tumor progression. Recently, vasohibin-1 and vasohibin-2 were detected in endothelial cells and considered as intrinsic angiogenesis inhibitors. However, it is not known whether they are also expressed in cancer cells or tumor-associated macrophages (TAMs). Realtime RT-PCR was used to investigate the vasohibin-1 and vasohibin-2 expression in four gastric cancer cell lines, including a non-metastatic cell line AGS, and metastatic cell lines HGC-27, Hs-746T and NCI-N87, co-cultured with or without TAMs. The effect of hypoxic conditions on vasohibin expression was evaluated as well, and the correlation between vasohibin-1, vasohibin-2 and VEGF-A expression under different culture conditions was analyzed. We found that both vasohibin-1 and vasohibin-2 were expressed in the four gastric cancer cell lines and in TAMs. Under normal conditions, vasohibin-1 and vasohibin-2 expressions were significantly upregulated by TAMs in all the gastric cancer cell lines. Under hypoxia, both vasohibin-1 and vasohibin-2 expressions were significantly decreased in the distant metastasis cancer cell line Hs-746T, cultured with or without TAMs (P<0.001). After induction by TAMs or hypoxia, the vasohibin-1 and vasohibin-2 expressions correlated with that of VEGF-A. In addition, TAMs, when co-cultured with the metastatic cancer cell lines, showed hypoxia-induced vasohibin-1 upregulation (P<0.05). In conclusion, both vasohibin-1 and vasohibin-2 mRNA are expressed in gastric cancer cells and in TAMs, and their expressions are altered by hypoxia.

Kindlin-2 might promote the invasion of gastric cancer cells through enhancing proliferation and adhesion by the phosphorylation of integrin β1 and β3.

Both macrophages and hypoxia play an indispensable role in regulating the invasion of gastric cancer cells in vitro; ADAMs, MMP9 and TIMP3 might be involved in TAM induced invasive power of gastric cancer cells.