Inhibitor of differentiation-1 promotes angiogenesis of human osteosarcoma by regulating VEGF-A

Abstract

Objective To investigate the effect of inhibitor of differentiation-1 (ID1) on angiogenesis in osteosarcoma cell line 143B by regulating vascular endothelial growth factor A (VEGF-A), and verify the correlation of ID1 expression with angiogenesis and VEGF-A expression in human osteosarcoma tissues. Methods We investigated the expression patterns of ID1 and microvessel density (MVD) in 33 human osteosarcoma tissues by immunohistochemistry (IHC) and further analyzed the correlation between ID1 and VEGF-A expression in osteosarcoma by IHC and bioinformatics analysis. Lentiviral vector and siRNA transfection were employed to make ID1 differential expressed in osteosarcoma 143B cells. And the conditional medium (CM) were collected. Transwell assay and tube formation assay were used to determine the effect of CM collected from ID1 differential expressed 143B cells on abilities of the migration and tube formation in human umbilical vein endothelial cells (HUVECs) in vitro. PCR, ELISA and Western blot assay were adopted to detect the responses of VEGF-A expression in 143B cells in vitro, with or without ID1 differential expression. Results Bioinformatics analysis indicated that ID1 was involved in many pathways related to the angiogenesis in osteosarcoma, and the expression of VEGF-A was positively correlated with the mRNA level of ID1. In the human osteosarcoma tissues, these with positive ID1 expression had higher MVD than those with negative expression (P < 0.05), and the protein level of ID1 had a positive correlation with that of VEGF-A (r=0.464 3, P=0.006 5). In vitro study showed that the CM collected from ID1 overexpression 143B cells significantly enhanced the abilities of migration and tube formation in HUVECs than the CM from control cells (P < 0.05), and the CM from ID1-silencing 143B cells obviously suppressed the abilities (P < 0.05). The expression and secretion of ID1 was enhanced in the ID1 overexpression 143B cells, but reduced in the ID1-silencing 143B cells (P < 0.05). Conclusion ID1 promotes angiogenesis in human osteosarcoma by up-regulating VEGF-A.

Keywords

• inhibitors of differentiation-1
• osteosarcoma
• vascular endothelial growth factor a
• angiogenesis