CD133通过上皮间质转化促进胃癌侵袭和转移的研究

目的观察胃癌细胞CDl33表达与胃癌侵袭的关系，进而探讨其是否通过上皮间质转化（EMT）促进胃癌侵袭和转移。方法通过免疫磁珠分选技术，将KATO-Ⅲ细胞分为CDl33阳性细胞和CDl33阴性细胞，利用Transwell小室法检测其侵袭能力，并通过Western blot和RT-PCR方法检测siRNA干扰CDl33基因沉默前后其EMT相关因子的表达差异。Western blot法检测50例胃癌组织及癌旁组织CDl33和EMT相关因子的表达．并分析其相关性。结果CDl33阳性组穿膜细胞数（67．7±10．5）显著高于CDl33阴性组（13．3±6．8，P=0．001）。CDl33阳性细胞中Snail和N-cadherinmRNA及蛋白表达显著高于CDl33阴性细胞．而E-cadherin表达则明显低于CDl33阴性细胞（均P〈0．05）。siRNA干扰后，Snail和N-cadherinmRNA及蛋白表达明显下调，而E-cadherin表达则显著上升（均P〈0．05）。胃癌组织中CDl33、Snail及N-cadherin蛋白相对表达为0．635±0．119、0．599±0．114及0．754±0．154，明显高于癌旁组织的0．485±0．116（P=0．029）、0．259±0．108（P=0．020）和0．329±0．134（P=0．001），而E-cadherin蛋白表达相对表达为0．378±0．123，明显低于癌旁组织的0．752±0．156（P=O．003）。相关分析显示，Snail及N-cadherin的表达与CDl33表达呈正相关（P〈0．05），而E-cadherin的表达则与CDl33表达呈负相关（P〈O．05）。结论CDl33阳性胃癌细胞具有更强的侵袭能力，并可能通过EMT促进胃癌的侵袭和转移。

CD133 promotes the invasion and metastasis of gastric cancer via epithelial-mesenchymal transition

Objective To examine the association between CD133 expression and invasion of gastric cancer, and to elucidate whether CD133 can promote the invasion and metastasis of gastric cancer via epithelial-mesenchymal transition （EMT）. Methods The CD133＊ and CD133- KATO-Ⅲ cells were sorted by magnetic activated cell sorting （MACS）. The invasion ability was detected by Transwell method. RT-PCR and Western blot were used to detect the expression of EMT-related factors in KATO- Ill cells before and after CD133 was knocked out by siRNA method. The expressions of CD133 and EMT- related proteins of cancer and adjacent normal tissues in 50 patients with gastric cancer were detected by Western blot, and correlations among protein expressions were also analyzed. Results As compared to CD133- cells, the number of broken-membrane cells was significantly higher （67.7±10.5 vs. 13.3±6.8, P= 0.001） and the invasion ability was stronger （P〈0.05） in CD133＋ cells, while the mRNA expression levels of Snail and N-cadherin were significantly higher in CD133＋ cells （0.311±0.015 vs. 0.223±0.016, P=0.040; 0.581±0.020 vs. 0.270±0.018,P=0.004）, and the protein expression levels of Snailand N-cadherin were significantly higher in CD133＊ cells as well （0.513±0.015 vs. 0.179±0.023, P= 0.030; 0.538±0.028 vs. 0.202±0.032, P=0.020）, but E-cadherin mRNA and protein levels were significantly lower in CD133＊ cells （0.231±0.009 vs. 0.460±0.015, P=0.040; 0.426±0.030 vs. 0.748±0.027, P=0.040）. After CD133 knock-out, the expressions of Snail and N-cadherin were down-regulated （P〈0.05） and the expression of E-cadherin was up-regulated（P〈0.05）. As compared to normal mucosal tissues, the protein expression levels of Snail, N-cadherin and CD133 in gastric cancer tissues were significantly higher （0.635±0.119 vs. 0.485±0.116, P=0.029 ; 0.599±0.114 vs. 0.259±0.108, P=0.020; 0.754±0.154 vs. 0.329±0.134, P=0.001）, while the protein expression of E-eadherin in gastric cancer tissues was lower （0.378±0.123 vs. 0.752±0.156, P=O.O03）. The protein expressions of Snail and N-cadherin were positively correlated with CD133 expression （r=0.278,P=0.048;r0.406,P=0.003） and the protein expression of E-cadherin was negatively correlated with CD133 expression （r=-0.504, P=0.O00）. Conclusion CD133＋ cells in primary lesion of gastric cancer have relatively higher invasion ability, which may promote the metastasis of gastric cancer via up-regulation of EMT-related factors.