Oligomer procyanidins (F2) isolated from grape seeds inhibits tumor angiogenesis and cell invasion by targeting HIF-1α in vitro.

Overexpression of hypoxia-inducible factor-1 (HIF-1) α, a transcription factor which immortalizes tumors by inducing expression of the genes involved in cell survival, migration and angiogenesis, is closely associated with poor prognosis, increased risk of metastasis and increased mortality. Oligomer procyanidins (F2), a natural fraction from grape seeds, has been demonstrated to have antioxidant and antitumor activities, however the antitumor effect of F2 targeting HIF-1α remains unknown. The present study showed that F2 markedly decreased HIF-1α and the expression of its target genes in cancer cells through inactivating the EGFR-PI3K-AKT-mTOR and MAPK-ERK1/2 pathways. Moreover, F2 suppressed vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 expressions, followed by the inhibition of tumor angiogenesis and cell invasion in a HIF-1α-dependent manner. Collectively, these findings indicate that the antitumor effect of F2 is, at least in part, mediated by suppressing HIF-1α-dependent pathway, and suggest that F2 may be a potentially useful agent for treatment of human cancer.