CTEN Inhibits Tumor Angiogenesis and Growth by Targeting VEGFA Through Down-Regulation of β-Catenin in Breast Cancer.

C-terminal tensin-like (CTEN) belongs to the tensin gene family, which encodes proteins that localize to focal adhesions and modulate integrin function. Accumulating studies have reported that CTEN expression can be upregulated or downregulated in different types of cancers, suggesting that CTEN has both oncogenic and tumor suppressor functions. In this study, by analyzing the expression level of CTEN in the human breast cancer (BRCA) samples from the clinically annotated genomic database, The Cancer Genome Atlas, we found that CTEN was downregulated in different BRCA subclasses, including luminal, human epidermal growth factor receptor 2 positive and triple-negative BRCA. Consistently, the protein level of CTEN was also reduced in BRCA based on the Proteomic Tumor Analysis Consortium. In contrast, vascular endothelial growth factor A (VEGFA), a signal protein that stimulates the formation of blood vessels, was upregulated in BRCA. CTEN overexpression in human umbilical vein endothelial cells and MCF7 significantly suppressed the expression of VEGFA, inhibited cell proliferation, migration, and tube formation in vitro. Mechanistically, CTEN bind to casitas B-lineage lymphoma (c-Cbl), an E3 ubiquitin-protein ligase, and decreased the β-catenin expression. In turn, the downregulation of β-catenin reduced the expression of VEGFA. Rescuing β-catenin expression effectively ameliorated the effect of CTEN overexpression in cell proliferation, migration, and tube formation. In conclusion, CTEN inhibited tumor angiogenesis by targeting VEGFA through c-Cbl-mediated down-regulation of β-catenin and may serve as a tumor suppressor in BRCA.