Abstract:

Objective The purpose of this study was to investigate the regulatory role of tyrosine kinase 2 with immunoglobulin-like and epidermal growth factor homology domains（Tie2）on apoptosis and proliferation in the endothelial cells. Methods RNA interference（RNAi） technique was used to silence Tie2 gene expression by transfecting an expression vector containing short hairpin RNA（shRNA） for Tie2 into human umbilical vein endothelial cells（HUVECs）. Real time quantitation reverse transcriptase polymerase chain reaction（QRT-PCR） and Western blot were used to monitor Tie2 mRNA, as well as protein expression. The proliferation of HUVECs was examined by methyl thiazolyl tetrazolium（MTT）, and the apoptosis was detected under microscope. HUVECs transfected with pGenesil-hk was negative control, and HUVECs transfected with nothing was empty control. Results Tie2 mRNA expression was down-regulated 24 h and 48 h after transfection, and Tie2 protein expression was significantly down-regulated at 24 h and 48 h（P<0.05）, especially 48 h after transfection. The apoptosis rate was conspicuously higher in experimental group than in negative control and empty control group after 48 h（P<0.05）. The growth monitoring showed that proliferation was also markedly inhibited in experimental group（P<0.05） compared with two control groups. Conclusion Down-regulated expression
of Tie2 by RNAi can promotes apoptosis of HUVECs and has an anti-proliferation activity effect on them.

Key words: tyrosine kinase 2 with immunoglobulin-like and epidermal growth factor homology domains, apoptosis, human umbilical vein endothelial cells, proliferation, anti-angiogenesis