Role and mechanism of DCLK1 in gastric cancer stem cells / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effect of doublecortin-like kinase 1(DCLK1)on the biological properties of gastric cancer stem cells,and to explore its possible mechanism.METHODS:Serum-free suspension culture of gastric cancer stem cells and targeted inhibition of DCLK1 activity in gastric cancer stem cells with DCLK1 inhibitor DCLK1-IN-1 were performed.The expression levels of DCLK1,stemness-related proteins(SOX2 and OCT4),proliferation-related pro-teins(cyclin D1 and c-MYC),drug resistance-related proteins(ABCG2 and TOP2A),epithelial-mesenchymal transition-related proteins(E-cadherin,vimentin and Snail),and PI3K/AKT/mTOR signaling pathway-related proteins in gastric cancer stem cells were examined by Western blot.The effects of DCLK1 on viability and drug resistance of gastric cancer stem cells were determined by CCK-8 assay,and the effects of DCLK1 on self-renewal of gastric cancer stem cells were de-termined by methylcellulose spheroid-forming assay.Wound-healing and Transwell assays were performed to assess the ef-fect of DCLK1 on the migration and invasion of gastric cancer stem cells.RESULTS:The expression levels of DCLK1 and stemness-related proteins SOX2 and OCT4 in gastric cancer stem cells were significantly higher than those in parental cells(P＜0.01).The proliferation,drug resistance,migration and invasion of gastric cancer stem cells in DCLK1 inhibi-tion group were significantly lower than those in Sphere cell group(P＜0.01).The expression levels of proliferation-related proteins(c-MYC and cyclin D1)and drug resistance-related proteins(TOP2A and ABCG2)were down-regulated,the ex-pression of epithelial marker E-cadherin was up-regulated,the expression of mesenchymal markers vimentin and Snail was down-regulated,and the expression levels of PI3K/AKT/mTOR signaling pathway-related proteins and their phosphoryla-tion levels were reduced in DCLK1 inhibition group(P＜0.05).CONCLUSION:DCLK1 is highly expressed in gastric cancer stem cells,which may be involved in the proliferation,drug resistance and invasion of gastric cancer stem cells by regulating PI3K/AKT/mTOR signaling pathway.It suggests that DCLK1 can be used as a potential target for gastric cancer stem cells.