人A431皮肤鳞状细胞癌中丝裂原活化蛋白激酶/细胞外信号调节激酶信号通路对P53的调节作用

MAPK/ERK regulation of P53 in human epidermoid carcinoma cell line A431

摘要:

目的  观察丝裂原活化蛋白激酶/细胞外信号调节激酶（MAPK/ERK）信号通路的活化及抑制对皮肤鳞状细胞癌（SCC）细胞增殖、凋亡情况的影响，探讨MAPK/ERK信号通路与抑癌基因P53在皮肤SCC中的相互作用机制。方法  培养人A431皮肤SCC细胞株，分为低、中、高浓度的MAPK/ERK通路抑制剂（PD98059+DMSO）组及激活剂（IGF+PBS）组、空白对照（DMSO）组。噻唑蓝法检测细胞体外增殖活力，流式细胞术（FCM）检测细胞的凋亡，Western blot检测各组A431细胞中P-ERK、P53蛋白表达。结果  经不同浓度的抑制术PD98059处理A431细胞，细胞增殖受到抑制，呈浓度-效应和时间-效应关系（P <0.05）；经不同浓度的激动剂胰岛素样生长因子（IGF）处理A431细胞，细胞增殖受到促进，呈浓度-效应和时间-效应关系（P <
0.05）。FCM检测结果显示，PD98059作用于A431细胞，细胞凋亡率明显增高，呈浓度-效应关系（P <0.05）；而IGF作用于A431细胞，细胞凋亡率明显降低，呈浓度-效应关系（P <0.05）。Western blot检测结果显示，PD98059处理A431细胞，P-ERK蛋白的表达降低，P53蛋白的表达增强，随着PD98059浓度的增加，P-ERK蛋白明显降低，P53蛋白明显增强（P <0.05）；而IGF处理A431细胞，P-ERK蛋白的表达增强，P53蛋白的表达降低，随着IGF浓度的增加，P-ERK蛋白明显增强，P53蛋白明显降低（P <0.05）；经过Pearson相关性分析，P53与P-ERK的表达呈负相关（P <0.05）。结论  人A431细胞中MAPK/ERK信号通路被IGF激活后，促凋亡因子P53表达降低，细胞增殖能力增强，凋亡能力降低；而该通路受抑制后，促凋亡因子P53表达增高，细胞增殖能力降低、凋亡能力增强。

Abstract:

Objective To observe the impact of activation or inhibition of MAPK/ERK signaling pathway on the proliferation and apoptosis of human epidermoid carcinoma cell line A431 cells, and to investigate the interaction mechanism between MAPK/ERK signaling pathway and tumor suppression gene P53. Methods Human A431 cells were cultured and divided into MAPK/ERK inhibition groups of low-, medium- and high-concentration of inhibitor (PD98059 + DMSO), MAPK/ERK activation groups of low-, medium- and high-concentration of activator (IGF + PBS) and blank control group (DMSO). The in vitro cellular proliferation was detected by MTT assay, the cell apoptosis detected by flow cytometry (FCM) and the protein expression of p-ERK and p53 detected by Western blot in each group. Results The A431 cell proliferation was inhibited bydifferent concentrations of inhibitor PD98059 with a clear concentration-effect and time-effect relationship (P < 0.05), and the cell proliferation was promoted in the different concentrations of IGF with a clear concentration-effect and time-effect relationship (P < 0.05). The FCM result showed a significantly increased A431 cell apoptosis rate with increased PD98059 in a concentration-effect relationship (P < 0.05); while the apoptosis rate decreased significantly with increased IGF also in a concentration-effect relationship (P < 0.05).  The Western blot results showed that after PD98059 treatment the protein expression of p-ERK was reduced and the protein expression of p53 was enhanced, additionally the change of both expressions became much bigger when the concentration of PD98059 increased further with significant differences (P < 0.05). For the A431 cells treated by IGF, the protein expression of p-ERK was enhanced and protein expression of p53 was reduced with increasing concentrations of IGF, for which the differences were significant (P < 0.05) compared with the control group. The protein expressions of p-ERK and p53 were negatively correlated by Pearson correlation analysis (P < 0.05). Conclusions The activation of MAPK/ERK signaling pathway by IGF in human epidermoid carcinoma cell line A431 cells could reduce the expression of apoptosis factor p53, enhance cell proliferation capacity and reduce apoptosis capacity, while the inhibition of MAPK/ERK signaling pathway results in the increased expression of p53, decreased cell proliferation and enhanced apoptosis.