Abstract: Objective To explore growth inhibition and apoptosis induction effects of pLXSN-Tum-5 in human umbilical vein endothelial cells (HUVEC) and the mechanism of the effects.Methods HUVEC were treated with pLXSN-Tum-5 virus particles at different concentrations.Hoechst-33342 staining and 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay were utilized to monitor the growth states and morphological changes of HUVEC.Changes in the expressions of intracellular B cell lymphoma 2 (Bcl-2),Bcl-2-associated X (Bax),and caspase-3 at mRNA and protein levels were determined with real-time reverse transcription PCR (RT-PCR) and Western blot.Results The survival rate of HUVEC transfected with pLXSN-Tum-5 virus particles was significantly decreased in a dose-effect manner compared to that of the control (with pLXSN).Apoptotic bodies were observed in the HUVEC transfected with pLXSN-Tum-5.Significantly upregulated mRNA and protein expressions of Bcl-2 (1.134±0.0524 vs.0.721±0.041 and 1.012±0.0641 vs.0.654±0.034) and caspase-3 (1.612±0.067 vs.0.956±0.032 and 0.712±0.0647 vs.0.356±0.054) were observed in the HUVEC transfected with 20 mol/L pLXSN-Tum-5 virus particles compared to those in the control HUVEC (P<0.05 for all).Conclusion Human Tum-5 could inhibit proliferation and induce apoptosis in HUVEC,and the mechanism of the effects may be related to upregulated expressions of Bax/Bcl-2 and caspase-3 in the HUVEC.