VEGF induces phosphorylation of STAT3 through binding VEGFR2 in ovarian carcinoma cells in vitro

VEGF plays a key role in ovarian carcinoma. Recent studies have shown that expressions of VEGF and its receptors were correlated with signal tranducer phosphorylation and activators of transcription 3(p-STAT3) in ovarian carcinoma. The aim of this study was to investigate the effects of STAT3 phosphorylation on VEGF signaling pathways in ovarian carcinoma cells. We selected an ovarian carcinoma cell line Caov-3 as a target cell that co-expressed VEGFR2 and p-STAT3. We detected expressions of p-STAT3 in Caov-3 induced by VEGF with different concentrations and for different effect times by immunocytochemistry and Western Blot. A concentration of 50 ng/ml VEGF was enough to increase phosphorylation of STAT3, and at 30 min, the p-STAT3 level reached the peak and showed nuclear translocation of p-STAT3 from the cytoplasm to the nucleus. These effects could be overcome by a small peptide (ATWLPPR) specific for VEGFR2. Taken together, VEGF-induced phosphorylation and nuclear translocation of STAT3 and ATWLPPR could effectively block the VEGF effects, suggesting that phosphorylation of STAT3 participates in VEGF signal transduction via VEGFR2 in ovarian carcinoma cells.