| Background:In recent years,Liver cancer and gallbladder cancer have become important threats to human life and health along with the increase of incidence and mortality.At present,the main clinical treatment for liver cancer and gallbladder cancer is surgical resection.However,as it is difficult to diagnose the two cancers early,most patients are diagnosed when their cancer has already reached an advanced stage,which makes them miss the best timing for surgery.Besides,due to the lack of in-depth cancer pathogenesis,there are no sufficient effective therapies and anti-cancer drugs for the two cancers,resulting in that the two cancers have a poor prognosis.Long non-coding RNAs(lncRNAs)are one of the key regulating factors of gene expression,which also play important roles in human tumorigenesis.Previous studies have reported that lncRNA SNHG16 is highly expressed in multiple human tumors.It regulates the expression of the downstream genes to promote tumorigenesis and tumor growth as a miRNA sponge.However,it is still unclear how SNHG16 affects tumor cell cycle regulation and epithelial-mesenchymal transition(EMT),which are very crucial for tumor growth and metastasis.Research Purpose:This study demonstrates the effect of lncRNA SNHG16 on cell cycle and EMT in liver cancer cells and the molecular mechanism.In addition,it investigates the association between SNHG16 expression and anti-cancer drug sensitivity in liver cancer cells and the mechanism of SNHG16 on cell cycle regulation in gallbladder cancer cells.Methods:The expression levels of lncRNA SNHG16,miRNA and the downstream genes in tumor tissues and cells were detected by quantitative real-time PCR(qRT-PCR)and western blot.The correlation between lncRNA SNHG16 expression and prognosis in liver cancer patients was analyzed by survival curves.Liver cancer and gallbladder cancer cells with SNHG16 knockdown were established by lentivirus infection and drug selection.Cell cycle distribution and cell apoptosis were analyzed by using flow cytometry and the proteins related to cell cycle regulation,apoptosis and EMT were detected by western blot.Some in vitro assays,such as MTT,colony formation,wound-healing,and transwell invasion assay,were used to determine the effect of SNHG16 knockdown on cell proliferation,migration,and invasion in liver or gallbladder cancer cells.In animal experiments,the effect of SNHG16 downregulation on tumor growth and metastasis in vivo was confirmed.In addition,the association between SNHG16 and thesensitivity of liver cancer cells to cisplatin and apatinib were investigated by calculating IC50 of the two anti-cancer drugs.Bioinformatics analysis,Dual-luciferase reporter assay,RNA-binding protein immunoprecipitation assay(RIP),In vivo cell functional assays,rescue assay,and gene expression correlation analysis were also used to reveal the molecular mechanism of SNHG16 in promoting tumorigenesis and tumor progression.Results:This study finds that lncRNA SNHG16 highly expressed in liver tumor tissues and cell lines.The expression level of SNHG16 was associated negatively with the survival rate of liver cancer patients.The prognosis in patients with high SNHG16 expression was poorer than that with low SNHG16 expression.SNHG16 knockdown in liver cancer cells enhanced the cell sensitivity to cisplatin and apatinib.As a competitive endogenous RNA,lncRNA SNHG16 participates in the molecular regulatory network of the cell cycle through the SNHG16/let-7b-5p/CDC25B/CDK1 axis,and participates in the epithelial-mesenchymal transition molecular regulatory network through the SNHG16/let-7b-5p/HMGA2 axis in liver cancer.Meanwhile,lncRNA SNHG16 highly expressed in gallbladder cancer tumor tissues and cell lines.As a competitive endogenous RNA,lncRNA SNHG16 participatesin the molecular regulatory network of gallbladder cancer cell cycle and proliferation through SNHG16/ mir-3138 /CDC25B/CDK1 axis.Research Significance:This study reveals the signaling pathway of lncRNA SNHG16 regulating the tumor cell cycle and EMT and determines the correlation between SNHG16 expression and liver cancer cell sensitivity to anti-cancer drugs.It facilitates us to understand the function of lncRNA SNHG16,which provides new ideas to investigate how lncRNA regulates tumorigenesis and tumor progression,and reveal the pathogenesis of liver and gallbladder cancer.It also provides a theoretical basis to enhance cell sensitivity to anti-cancer drugs and develop novel anti-cancer targets. |
