title: [IL-12 induces autophagy via AKT/mTOR/STAT3 signaling pathway in human hepatoma cells].
abstract: Objective To investigate the effect of IL-12 on autophagy and the relative possible mechanism in HepG2 and SMMC-7721 human hepatoma cells. Methods The hepatoma cells were treated with IL-12 (10 ng/mL) for 6 hours. Western blotting was applied to detect the expressions of microtubule-associated protein 1 light chain 3 (LC-3), Beclin 1 and the phosphorylated levels of protein kinase B (AKT), mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 (STAT3); immunofluorescence assay (IFA) and transmission electron microscopy (TEM) were used to observe the formation of autophagosome. After STAT3 was inhibited by STATTIC or siSTAT3 and AKT was activated by insulin-like growth factor (IGF-1), Western blotting and IFA were performed again to analyze the change of IL-12-induced autophagy. After the cells were treated with IL-12 (10 ng/mL) for 1, 2, 3, 4, 5 days, CCK-8 assay was used to determine the growth ability. After the hepatoma cells were treated with IL-12 (10 ng/mL) for 48 hours, trypan blue staining was used to detect the death rate of the cells. After cell autophagy was inhibit by siBeclin 1, CCK-8 assay and trypan blue staining were performed again to study the effect of IL-12 on the proliferation and death of human hepatoma cells. Results IL-12 induced autophagy and inhibited cell growth in the hepatoma cells. Silencing Beclin 1 gene enhanced IL-12-mediated growth inhibition and cell death. Furthermore, IL-12 treatment also decreased the expressions of p-AKT, p-mTOR and p-STAT3. The pretreatment of siSTAT3 or STATTIC inhibited STAT3-enhanced IL-12-induced autophagy. Accordingly, activation of AKT with IGF-1 decreased IL-12-induced autophagy. Conclusion IL-12 could induce autophagy through AKT/mTOR/STAT3 signaling pathways and the induction of autophagy attenuates the growth-inhibitory effect of IL-12 on hepatoma cells.
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Cuiying
authors.initials: C
authors.lastname: Liu
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Changli
authors.initials: C
authors.lastname: Xie
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Bitao
authors.initials: B
authors.lastname: Wu
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Li
authors.affiliation: Ministry-of-Education Key Laboratory of Clinical Diagnostic Medicine, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. *Corresponding author, E-mail: tuzhiguang@aliyun.com.
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Tu
mesh_terms: D000071182:Autophagosomes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics; D056945:Hep G2 Cells; D006801:Humans; D018664:Interleukin-12 / Q000494:pharmacology*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
chemical_list: D050796:STAT3 Transcription Factor; D018664:Interleukin-12; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases