title: Downregulation of SNAIL sensitizes hepatocellular carcinoma cells to TRAIL-induced apoptosis by regulating the NF-κB pathway.
abstract: Hepatocellular carcinoma (HCC) is the sixth most common cancer and the second most lethal cancer worldwide. Evidence has shown HCC cell resistance to TRAIL‑mediated apoptosis. In a previous study, we verified that silencing SNAIL downregulated the growth of HCC cells. In addition, the mechanism of resistance to TRAIL in HCC cells was connected with the activation of nuclear factor-κB (NF-κB). Thus, it was hypothesized that the downregultaion of SNAIL sensitizes HCC cells to TRAIL-induced apoptosis by regulating the NF-κB pathway. In the present study, the most effective lentiviral vectors carrying shRNA against SNAIL were selected and adenoviral vectors harboring TRAIL were constructed. The expression of SNAIL and TRAIL was detected by quantitative PCR and western blotting. HCC cell viability and apoptosis were assessed using an MTT assay and the Hoechst test. To determine how to sensitize HCC cells to TRAIL-induced apoptosis after silencing SNAIL, p53 was assessed by western blot analysis. We also investigated the expression of Bcl-xL, cIAP2, survivin and Raf-1 protein using western blot analysis and the apoptotic degree of HuH-7 cells was detected using the Hoechst test following the suppression of each gene, which was a possible molecular mechanism to sensitive TRAIL-induced apoptosis through the downregulation of SNAIL in HCC cells. Silencing SNAIL resulted in increased apoptosis by enhancing sensitization to TRAIL in all the HCC cells. Additionally, p53 protein was upregulated in HuH-7 cells. Expression of Bcl-xL, cIAP2, survivin and Raf-1 was downregulated following silencing of SNAIL, while down-regulation of any of the proteins contributed to SNAIL suppression enhancing HCC cell sensitivity to TRAIL‑induced apoptosis, with the exception of cIAP2. The results demonstrated that silencing SNAIL can sensitize TRAIL-induced apoptosis in HCC cells by upregulating p53 protein and by regulating related genes of the NF-κB pathway such as Bcl-xL, survivin and Raf-1.
authors.affiliation: Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Zhaojun
authors.initials: Z
authors.lastname: Wan
authors.affiliation: Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Huazheng
authors.initials: H
authors.lastname: Pan
authors.affiliation: Department of Central Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Shihai
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Jingjuan
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Qi
authors.affiliation: Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Fu
authors.affiliation: Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Teng
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liang
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation; D057809:HEK293 Cells; D056945:Hep G2 Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000096:biosynthesis; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology*; D016328:NF-kappa B / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf / Q000096:biosynthesis; D034622:RNA Interference; D034741:RNA, Small Interfering; D000071250:Snail Family Transcription Factors; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000096:biosynthesis / Q000235:genetics*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000096:biosynthesis; D051020:bcl-X Protein / Q000096:biosynthesis
chemical_list: C494811:BCL2L1 protein, human; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D016328:NF-kappa B; D034741:RNA, Small Interfering; D000071250:Snail Family Transcription Factors; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D051020:bcl-X Protein; C494832:BIRC3 protein, human; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D044767:Ubiquitin-Protein Ligases; D019908:Proto-Oncogene Proteins c-raf