Objective To summarize the roles of tumor initiating cells （TICs） and epithelial-mesenchymal transition （EMT） in tumor metastasis and drug resistance. Methods Domestic and international publications online which involving TICs，EMT，and its roles in tumor metastasis and drug resistance in recent years were reviewed. Results TICs were self-renewal cells and had the ability to give rise to more differentiated cell types，and played an important role in tumor metastasis and drug resistance. Various markers had been used to identify TICs，such as CD133，CD44，and so on. EMT was the process by which epithelial cells losed polarity and detach from the epithelial sheet， and acquired a motile mesenchymal phenotype，usually observed in embryo development and wound healing. It also could promote tumor progression and metastasis，and may also be responsible for the ability of tumors to evade the body’s immune response. EMT may be the reasons of TICs that drived tumor metastasis and recurrence. TICs or EMT as a target for treatments may effectively prevent tumor recurrence and improve patient’s survival. Conclusions EMT is probably the mechanism that TICs promote tumor metastasis and drug resistance. More effective target therapies for cancer may be found if we know more about TICs and EMT.
ObjectiveTo summarize the role of epithelial-mesenchymal-transition （EMT） in occurrence and development of gastrointestinal cancer. MethodsDomestic and international publications online involving EMT of gastrointestinal cancer in recent years were collected and reviewed. ResultsEMT was a highly conserved process that has been well characterised in embryogenesis. Studies had shown that the aberrant activation of EMT in adult epithelia could promote tumour metastasis by repressing cell adhesion molecules. E-cadherin， one of the epithelial cell markers, maybe involved in the process of the EMT, especially of the Ecadherin transcriptional repressors， these transcriptional repressors significantly increased in the gastrointestinal cancer. Further more， EMT might involve in the process of gastrointestinal cancer stem cells formation. ConclusionsEMT and it’s regulators play a very important role in gastrointestinal cancer， and may provide a newsight into the gastrointestinal cancer. It also can provide a novel clinical targets to treat the gastrointestinal cancer.
Objective To investigate the prognostic value of epithelial-mesenchymal transition （EMT） related proteins （Snail， E-cadherin， and N-cadherin） in gastric cancer and its relationship with tumor initiating cells （TICs） marker （CD133）. Methods The expressions of EMT-related proteins and CD133 protein in the gastric cancer tissues and normal gastric mucosa tissues adjacent to gastric cancer were detected by Western blot method. The relations between the expressions of EMT-related factors proteins and CD133 protein and the clinicopathologic characters were analyzed. The correlations between EMT-related factors and CD133 were analyzed by Spearman. The correlations between EMT-related factors expressions and CD133 expression and survival were analyzed by Kaplan-Meier method and Log-rank test. Results ① The protein expression levels of Snail， N-cadherin， and CD133 in the gastric cancer tissues were significantly higher than those in the normal gastric mucosa tissues adjacent to gastric cancer （Snail：0.599±0.114 versus 0.259±0.108， P=0.020；N-cadherin：0.754±0.154 versus 0.329±0.134， P=0.001；CD133：0.635±0.119 versus 0.485±0.116， P=0.029）， while the protein expression level of E-cadherin was lower than that in the normal gastric mucosa tissues adjacent to gastric cancer （0.378±0.123 versus 0.752±0.156， P=0.003）.② The expression levels of Snail and N-cadherin in the gastric cancer patients with vascular invasion， lymphatic vessel invasion，N3 lymph node metastasis， diameter more than 5 cm， and Ⅲ＋Ⅳ staging were significantly higher than those in the patients without vascular invasion， lymphatic vessel invasion， N0-N2 lymph node metastasis， diameter less than 5 cm， andⅠ＋Ⅱ staging（P＜0.05）， while E-cadherin protein expression was lower than that in the patients without vascular invasion， lymphatic vessel invasion， N0-N2 lymph nodes metastasis， andⅠ＋Ⅱstaging （P＜0.05）. The expression levels of CD133 in the gastric cancer patients with lymphatic vessel invasion， diameter more than 5 cm， and Ⅲ＋Ⅳ staging were significantly higher than those in the patients without lymphatic vessel invasion， diameter less than 5 cm， andⅠ＋Ⅱ staging （P＜0.05）. ③The Snail and N-cadherin protein expressions were significantly positive correlated with CD133 protein expression， respectively （rs=0.278， P=0.048；rs=0.406， P=0.003）， while E-cadherin protein expression was significantly negative correlated with CD133 protein expression （rs=-0.504， P=0.000）.④ The survival time in the patients with lower expressions of Snail， N-cadherin， and CD133 were significantly longer than those in the patients with higher expressions of Snail， N-cadherin， and CD133 （P＜0.05）. The combination of Snail， N-cadherin， E-cadherin， and CD133 could effectively predict survival. Conclusions There is a significant correlation between EMT and gastric cancer TICs， and which are correlated with aggressive clinicopathologic features of gastric cancer. The combination of Snail， E-cadherin， N-cadherin， and CD133 may be effectively predict the prognosis of gastric cancer patients.