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 ference 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 carcino-ma,and the molecular mechanism may be correlated with hindering the transportion of NF-κB into cell nuclear.
ABSTRACT
In order to investigate the effects of a fermented soybean product (Chungkookjang, CKJ) on nerve growth factor (NGF) metabolism, NGF secretion ability and its related signaling pathway were analyzed in B35 neuronal cells and the Tg2576 mouse model of Alzheimer's disease (AD). In B35 cells, the concentration of NGF significantly increased upon treatment with Taegwang (TG)-CKJ and Shinhwa (SH)-CKJ extracts compared with vehicle. Further, a significant increase in PC12 cell length as well as the phsophorylation levels of TrkA and Akt, which are members of a high affinity NGF receptor signaling pathway, were observed after treatment with TG-CKJ and SH-CKJ conditional medium (CM). On the other hand, there was no difference in activation of the NGF receptor p75NTR signaling pathway between vehicle and all CKJ treated groups. In Tg2576 mice showing early stage of AD, the concentrations of NGF in the serum and brain were reduced compared with those in Non-Tg mice. Treatment of Tg2576 mice with SH-CKJ, which contains high concentrations of total flavonoids and phenolic compounds, for 8 weeks dramatically recovered the NGF level to that of Non-Tg mice. Furthermore, the low phosphorylation levels of TrkA and Erk in the NGF receptor TrkA signaling pathway were rapidly recovered to those of Non-Tg mice after SH-CKJ treatment in vehicle treated Tg2576 mice, whereas the phosphorylation level of Akt was maintained at a constant level. These results suggest that CKJ may stimulate NGF secretion ability as well as the NGF receptor TrkA signaling pathway in PC12 cells and Tg2576 mice.