Abstract
Angiogenesis is critical for solid tumor growth beyond its minimal size. Previously, we reported that Down Syndrome Candidate Region 1 isoform 1L (DSCR1-1L) was one of the most up-regulated genes in endothelial cells induced by VEGF and histamine, and regulated endothelial cell proliferation, migration and angiogenesis. However, it was not known whether DSCR1-1L played a role in tumor growth. In this study, we found that DSCR1-1L shRNAs significantly inhibited the growth of transplanted melanoma in mice and its associated tumoral angiogenesis. In the gain of function assay, overexpression of DSCR1-1L cDNA in mouse endothelium is sufficient to significantly increase the tumor initiation induced by carcinogen, the growth of xenografted tumor, and the tumor metastasis in our endothelially-expressed DSCR1-1L transgenic mice, in which angiogenesis was induced. It was the first time to find that DSCR1-1L was also expressed in various tumor cells. DSCR1-1L shRNAs inhibited, but overexpression of DSCR1-1L cDNA increased, the tumor cell proliferation and migration. Most recently, we reported that DSCR1-1L modulated angiogenesis by down-regulation of VE-cadherin expression. Here, we found that DSCR1-1L down-regulated the expression of E-cadherin. Hence, DSCR1-1L is an excellent therapeutic target for cancers by regulation of both the endothelial and tumor cells through down-regulating (V)E-cadherin. DSCR1-1L shRNAs have the potential to be developed for clinical application.