烟酰胺N甲基转移酶在食管癌中的表达及机制研究

Mechanism and Expression of Nicotinamide N-methyltransferase in Esophageal Carcinoma

目的探讨烟酰胺N甲基转移酶(NNMT)在食管癌中的表达及机制。方法采用免疫组化法检测84例食管癌及癌旁正常组织中NNMT的表达,将siRNA NC(对照组)、siRNA NNMT(siRNA组)转染到EC9706食管癌细胞,Realtime PCR检测NNMT mRNA表达,CCK-8实验检测细胞活力,Hoechst染色检测细胞凋亡,Transwell实验检测细胞侵袭能力,Western blot检测NNMT、Wnt1a、β-catenin、CyclinD1、MMP-9蛋白表达。结果NNMT在食管癌组织(59/84,70.23%)中的阳性表达显著高于癌旁正常组织(4/84,4.69%)(χ^(2)=76.825,P<0.05)。与对照组比较,siRNA组NNMT mRNA[(0.56±0.05)vs(1.00±0.10),t=5.903,P<0.05]及蛋白表达量[(0.74±0.07)vs(1.56±0.16),t=7.321,P<0.05]均下调,细胞活力[(0.39±0.04)vs(0.62±0.06),t=5.832,P<0.05]降低,细胞凋亡率[(32.46±3.24)%vs(3.31±0.32)%,t=6.431,P<0.05]提高,细胞侵袭数目[(32.47±3.25)vs(189.32±18.90),t=6.321,P<0.05]减少,Wnt1a[(0.41±0.04)vs(0.15±0.01),t=5.842,P<0.05]、β-catenin[(0.34±0.03)vs(0.17±0.02),t=5.216,P<0.05]、CyclinD1[(1.12±013)vs(0.39±0.04),t=6.438,P<0.05]、MMP-9[(0.87±0.09)vs(0.31±0.03),t=5.128,P<0.05]表达量均下调。结论NNMT在食管癌组织中高表达,下调NNMT可以抑制EC9706食管癌细胞增殖与侵袭,与阻断Wnt/β-catenin信号通路有关。

Objective To explore the expression and mechanism of nicotinamide N-methyltransferase(NNMT)in esophageal carcinoma.Methods The expression of NNMT in 84 cases of esophageal carcinoma and adjacent normal tissues was detected by immunohistochemical method.EC9706 esophageal cancer cells were transfected with siRNA NC(control group)and siRNA NNMT(siRNA group).The expression of NNMT mRNA was detected by Realtime PCR.Cell viability was detected by CCK-8 assay.Cell apoptotic rate was detected by Hoechst staining.Cell invasion ability was detected by Transwell test.The expressions of NNMT,Wnt1a,β-Catenin,CyclinD1 and MMP-9 were detected by Western blot.Result The positive expression of NNMT in esophageal carcinoma(59/84,70.23%)was significantly higher than that in adjacent normal tissues(4/84,4.69%)(χ^(2)=76.825,P<0.05).Compared with control group,the expression of NNMT mRNA[(0.56±0.05)vs(1.00±0.10),t=5.903,P<0.05]and protein[(0.74±0.07)vs(1.56±0.16),t=7.321,P<0.05]was down-regulated,cell ability was decreased[(0.39±0.04)vs(0.62±0.06),t=5.832,P<0.05],cell apoptotic rate was increased[(32.46±3.24)%vs(3.31±0.32)%,t=6.431,P<0.05],cell invasion number was reduced[(32.47±3.25)vs(189.32±18.90),t=6.321,P<0.05],the expression of Wnt1a[(0.41±0.04)vs(0.15±0.01),t=5.842,P<0.05],β-catenin[(0.34±0.03)vs(0.17±0.02),t=5.216,P<0.05],CyclinD1[(1.12±013)vs(0.39±0.04),t=6.438,P<0.05],MMP-9[(0.87±0.09)vs(0.31±0.03),t=5.128,P<0.05]was down-regulated.Conclusion The expression of NNMT in esophageal carcinoma was higher,down-regulation of NNMT could inhibit the proliferation and invasion of EC9706 esophageal cancer cells,which related to blocking Wnt/β-catenin signaling pathway.