DCLK1在胃癌干细胞中的作用及机制研究

Role and mechanism of DCLK1 in gastric cancer stem cells

目的:研究双皮质素样激酶1(doublecortin-like kinase 1,DCLK1)对胃癌干细胞生物学特性的作用,初步探讨其可能的作用机制。方法:无血清培养液悬浮培养胃癌干细胞,用DCLK1抑制剂DCLK1-IN-1靶向抑制胃癌干细胞中DCLK1活性。用Western blot法检测胃癌干细胞中DCLK1、干性相关蛋白(SOX2和OCT4)、细胞增殖相关蛋白(cyclin D1和c-MYC)、耐药相关蛋白(ABCG2和TOP2A)、上皮-间充质转化相关蛋白(E-cadherin、vimen‐tin和Snail)和PI3K/AKT/mTOR信号通路相关蛋白表达水平。用CCK-8法测定DCLK1对胃癌干细胞活力及耐药的影响;用甲基纤维素成球法测定DCLK1对胃癌干细胞自我更新的影响。用细胞划痕实验和Transwell实验测定DCLK1对胃癌干细胞迁移和侵袭功能的影响。结果:胃癌干细胞中DCLK1及干性相关蛋白SOX2和OCT4表达明显高于亲本细胞(P<0.01)。DCLK1抑制组胃癌干细胞的增殖、耐药、迁移和侵袭能力明显低于Sphere细胞组(P<0.01)。DCLK1抑制组细胞增殖相关蛋白c-MYC和cyclin D1表达下调,耐药相关蛋白TOP2A和ABCG2表达下调,上皮标志物E-cadherin表达上调,间充质标志物vimentin和Snail表达下调,PI3K/AKT/mTOR相关蛋白表达及其磷酸化水平降低(P<0.01)。结论:DCLK1在胃癌干细胞中高表达,它可能通过调控PI3K/AKT/mTOR信号通路促进胃癌干细胞增殖、耐药、侵袭和迁移。DCLK1可作为靶向胃癌干细胞的潜在靶点。

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 proteins(cyclin D1 and c-MYC),drug resistance-related proteins(ABCG2 and TOP2A),epithelial-mesenchymal transitionrelated 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 determined by methylcellulose spheroid-forming assay.Wound-healing and Transwell assays were performed to assess the effect 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 inhibition 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 expression 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 phosphorylation 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.