Molecular mechanism of P75NTR gene-induced apoptosis in tongue squamous cell carcinoma cell

Abstract

Objective To investigate the molecular mechanism of P75NTR gene-induced apoptosis in tongue squamous cell carcinoma Tca8113 cell lineage. Methods P75NTR specific siRNA was transferred into P75NTR positive tongue squamous cell carcinoma Tca8113 cells. P75NTR positive Tca8113 cells were divided into 4 groups: blank group (without transfection), negative control group (transfected with negative control siRNA), experiment group-776 (transfected with siRNA-P75NTR-776) and experiment group-1234 (transfected with siRNA-P75NTR-1234). Transfection efficiency and cell apoptosis were detected by flow cytometry. The interference effect of P75NTR mRNA expression was detected by fluorescence quantitative PCR. 3-(4, 5-dimethyl-2-thiazoly)-2, 5-diphenyl-2H-tetrazolium bromide assay was applied in measuring cell prolife-ration. The protein changes of P75NTR were detected by Western blotting. The distributions of nuclear factor-κB(NF-κB) of cells were observed by cell immunofluorescence labeling method. Results The transfection efficiency was 30%. The apoptosis rate of experiment group-776, experiment group-1234 and negative control group was (20.35±0.18) %, (12.32±1.51)% and (2.63±0.10)% respectively. Compared with the negative control group, the differences of the former two group had statistical significance (t=177.20, P<0.005; t=37.12, P<0.005). The P75NTR gene interference was successful. The inhibition rate of P75NTR protein reached 31% in experiment group-776. The cell viability of Tca8113 cells after P75NTR-siRNA interference was 70.02%, 78.01% and 95.81% in experiment group-776, experiment group-1234 and negative control group. And there were significant differences between experiment group-776 and negative control group(χ2= 235.3, P<0.010), and between experiment group-1234 and negative control group (χ2= 117.5, P<0.005). NF-κB distribution was increased in cell cytoplasm in the interference group than that in control group. Conclusion P75NTR may promote the proliferation or inhibit the apoptosis of tongue squamous cell carcinoma, and the molecular mechanism may be correlated with hindering the transportion of NF-κB into cell nuclear. Key words: Apoptosis; Nerver growth factor; NF-Kappa B