Lidamycin inhibits angiogenesis of zebrafish embryo via down-regulation of VEGF

Lidamycin (LDM) is a potent antitumor antibiotic. Previous studies have shown that LDM could inhibit proliferation and migration in endothelial cells. In the present report, the effect of LDM on angiogenesis of zebrafish embryo was studied. The results showed that treatment of zebrafish embryos with LDM resulted in significant inhibition of angiogenesis. Morphological observation, quantitative endogenous alkaline phosphatase (EAP) assay, alkaline phosphatase staining, and transgenic zebrafish assay were performed to evaluate vascular development defects in zebrafish. The results indicated that after the zebrafish embryos were exposed to LDM, angiogenesis defects of zebrafish embryos were observed, including pericardial edema, reduced numbers of circulating red blood cells, suppression of zebrafish vessel growth, and absences of SIV (subintestinal vein). The expression of VEGF was detected by RT-PCR assay, quantitative reverse transcriptase real-time PCR (qRT-PCR) assay and Western blotting analysis. The results revealed that LDM could inhibit the expression of VEGF protein, while the expression of mRNA was not significantly affected. The study suggests that LDM could inhibit the zebrafish embryo angiogenesis by down-regulation of VEGF expression.