Gecko ethanol extract inhibits lymph angiogenesis through the VEGF-C/VEGFR-3 pathway in vitro and in vivo

Gecko ethanol extract (GEE) is an active component extracted from the gecko, and has been reported to be effective against hepatocellular carcinoma (HCC). However, its potential effects and mechanisms, by which it inhibits HCC lymph angiogenesis, are still unclear. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the anti-proliferative effect of GEE on human liver carcinoma HepG2 cells, and the expression level of vascular endothelial growth factor-C (VEGF-C) was detected. BALB/c mice bearing H22 hepatoma were randomly divided into model group (normal saline), control group (adriamycin, 2 mg.kg(-1)) and low, middle and high dose of GEE (20, 40 and 80 mg.kg(-1)) groups. The tumors were removed and the lymphatic micro vessel density (LMVD) was measured. Western blot and reverse transcription-PCR (RT-PCR) were used to detect VEGF-C and VEGFR-3. Results showed that GEE significantly inhibited the proliferation of HepG2, and the expression of VEGF-C decreased with increasing GEE concentration. In addition, GEE markedly inhibited transplanted tumor growth. A lower LMVD was detected in the GEE groups, and the protein and mRNA expression of VEGF-C and VEGFR-3 were also down-regulated. Our results indicate that GEE has a significant inhibitory effect on lymph angiogenesis in hepatic carcinoma. This may occur through the suppression of VEGF-C/VEGFR-3 signaling pathways.