Transforming growth factor-β1 induces epithelial-to-mesenchymal transition and promotes abtaining of stemness characteristics in gastric cancer

Objective To investigate if TGF-β1 induces epithelial-mesenchymal transition (EMT) and promotes the obtaining of stemness characteristics in gastric cancer cell lines.Methods After KATO-Ⅲ cells were cultured with or without 5 ng/mL TGF-β1,the morphological change was observed and compared under phase-contrast microscopy.At the same time,the effect of TGF-β1 on the proliferation of KATO-Ⅲ cells was detected by CCK-8.On the other hand,the mRNA and protein' s expressions of EMT-related factors,ESC markers and TICs markers were analyzed by RT-PCR and Western blotting methods too.Results TGF-β1 induced morphological alterations from epithelial to mesenchymal cells.The proliferation of KATO-Ⅲ cells was inhibited after treated with TGF-β1 (P ＜ 0.05).After treated with TGF-β1,the relative mRNA expression levels of Snail (0.5219 ±0.0147) and N-cadherin(0.6640 ±0.0124) were higher than that in control group(0.2049 ±0.0214,P =0.004,0.2722 ± 0.0098,P =0.001),the relative protein expression levels of Snail (0.4769 ± 0.0234) and N-cadherin (0.5014 ± 0.0216) were higher than that in control group (0.2534 ± 0.0345,P =0.02,0.2026 ± 0.0268,P =0.009),while the relative E-cadherin mRNA and protein levels in TGF-β1 treated group (0.4701 ± 0.0215,0.1349 ± 0.0258) were lower than that in control group (0.6792 ± 0.0157,P =0.01 ; 0.6055 ± 0.0227,P =0.004),while the relative mRNA expressions of ESC markers such as Sox2,OCT4,Nanog in TGF-β1 treated group (0.594 ± 0.039、0.438 ± 0.033、0.489 ± 0.037) were higher than that in control group (0.143 ± 0.013,P =0.001,0.156 ± 0.025,P =0.001,0.325 ± 0.046,P =0.03),the relative mRNA expression levels of CD44 (0.437 ±0.037) and CD133(0.543 ±0.028) were higher than that in control group (0.247 ±0.024,P =0.000,0.139 ± 0.016,P =0.000),the relative protein expression levels of CD44 (0.429 ± 0.034) and CD133 (0.316 ±0.027) in TGF-β1 treated group were higher than that in control group (0.152 ± 0.014,P =0.000,0.110 ±0.010,P =0.000),cloning sphere-forming capacity was greatly enhanced after treated with TGF-β1 (P ＜ 0.01).Conclusion TGF-β1 can induce EMT in KATO-Ⅲ cells and promote the obtaining of stemness characteristics in gastric cancer cell lines. Key words: Stomach neoplasms;  Epithelial mesenchymal transition;  Tumor initiating cells;  CD133; CD44