Inhibition of angiogenesis is a promising therapeutic strategy against cancer. In this study, we reported that ZLM-7, a combretastain A-4 (CA-4) derivative, exhibited anti-angiogenic activity in vitro and in vivo. In vitro, ZLM-7 induced microtubule cytoskeletal disassembly. It decreased VEGF-induced proliferation, migration, invasion and tube formation in endothelial cells, which are critical steps in angiogenesis. In vivo, ZLM-7 significantly inhibited neovascularization in a chicken chorioallantoic membrane (CAM) model and reduced the microvessel density in tumor tissues of MCF-7 xenograft mouse model. ZLM-7 also displayed comparable antiangiogenic and anti-tumor activities associated with the lead compound CA-4, but exhibited lower toxicity compared with CA-4. The anti-angiogenic effect of ZLM-7 was exerted via blockade of VEGF/VEGFR-2 signaling. ZLM-7 treatment suppressed the expression and secretion of VEGF in endothelial cells and MCF-7 cells under hypoxia. Further, ZLM-7 suppressed the VEGF-induced phosphorylation of VEGFR-2 and its downstream signaling mediators including activated AKT, MEK and ERK in endothelial cells. Overall, these results demonstrate that ZLM-7 exhibits anti-angiogenic activities by impairing endothelial cell function and blocking VEGF/VEGFR-2 signaling, suggesting that ZLM-7 might be a potential angiogenesis inhibitor.

SOX10 was identified as a methylated gene in our previous cancer methylome study. Here we further analyzed its epigenetic inactivation, biological functions and related cell signaling in digestive cancers (colorectal, gastric and esophageal cancers) in detail. SOX10 expression was decreased in multiple digestive cancer cell lines as well as primary tumors due to its promoter methylation. Pharmacologic or genetic demethylation reversed SOX10 silencing. Ectopic expression of SOX10 in SOX10-deficient cancer cells inhibits their proliferation, tumorigenicity, and metastatic potentials in vitro and in vivo. SOX10 also suppressed the epithelial to mesenchymal transition (EMT) and stemness properties of digestive tumor cells. Mechanistically, SOX10 competes with TCF4 to bind β-catenin and transrepresses its downstream target genes via its own DNA-binding property. SOX10 mutations that disrupt the SOX10-β-catenin interaction partially prevented tumor suppression. SOX10is thus a commonly inactivated tumor suppressor that antagonizes Wnt/β-catenin signaling in cancer cells from different digestive tissues.