Pro-apoptotic and migration-suppressing potential of EGCG, and the involvement of AMPK in the p53-mediated modulation of VEGF and MMP-9 expression

The present study investigated the regulatory mechanisms by which epigallocatechin-3-gallate (EGCG) exerts vascular endothelial growth factor (VEGF)-, p53- and AMP-activated protein kinase (AMPK)-associated pro-apoptotic and migration-suppressing effects on colon cancer cells. EGCG decreased the expression levels of VEGF and matrix metalloproteinase (MMP)-9. EGCG treatment induced apoptosis in the presence of wild-type and mutant p53, indicating that a p53-independent pathway may contribute to EGCG-induced apoptosis in these cells. EGCG showed migration-suppressing effects, suggesting that this activity may also have p53-dependent and-independent components. The interaction between p53 and VEGF in the EGCG-treated cells was investigated using pifithrin-a. Notably, the suppression of p53 activity blocked the ability of EGCG to inhibit VEGF and MMP-9 in the cells expressing wild-type p53, but not mutant p53, indicating that the effects of EGCG on VEGF may be p53-dependent or-independent. Finally, although AMPK and VEGF did not appear to co-localize, the results indicated that AMPK controls VEGF in EGCG-treated cells regardless of the p53 status.