title: Sulfatide interacts with and activates integrin αVβ3 in human hepatocellular carcinoma cells.
abstract: Integrin αVβ3 is a malignant driver of anchorage-independence and tumor angiogenesis, but its dysregulation in hepatocellular carcinoma (HCC) remains unclear. In this study, we observed that sulfatide significantly promoted integrin αV(ITGAV) expression and wound closure in HCC. We also noted that elevated sulfatide profoundly stimulated integrin αVβ3 clustering and signaling. In the cells with integrin αVβ3 clustering induced by sulfatide, integrin β3 subunit was phosphorylated. Simultaneously, focal adhesion kinase (FAK), Src and paxillin were also phosphorylated. Treatment with FAK inhibitor resulted in robust suppression of FAK-Y397 and Src-Y416 phosphorylation stimulated by sulfatide, but not suppression of integrin β3 phosphorylation. Src inhibitors repressed Src-Y416 and FAK Y861 and Y925 phosphorylation, but not FAK-Y397 and integrin β3 phosphorylation. After mutation of integrin β3 (Y773F and Y785F), FAK or Src phosphorylation failed to be stimulated by sulfatide. Moreover, β3 Y773 and Y785 phosphorylation was suppressed by insulin-like growth factor receptor knockdown even in cells stimulated by sulfatide. In assays of immunoprecipitation and immunostaining with integrin αV or β3 antibody, labeled sulfatide was found in the complex and co-localized with integrin αVβ3. Taken together, this study demonstrated that elevated sulfatide bound to integrin αVβ3 and induced clustering and phosphorylation of αVβ3 instead of matrix ligand binding, triggering outside-in signaling.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.|Key Laboratory of Glycoconjugate Research, Ministry of Public Health, Shanghai, PR. China.
authors.forename: Rong
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.|Key Laboratory of Glycoconjugate Research, Ministry of Public Health, Shanghai, PR. China.
authors.forename: Bing
authors.initials: B
authors.lastname: Qi
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.|Key Laboratory of Glycoconjugate Research, Ministry of Public Health, Shanghai, PR. China.
authors.forename: Yi Wei
authors.initials: YW
authors.lastname: Dong
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.|Key Laboratory of Glycoconjugate Research, Ministry of Public Health, Shanghai, PR. China.
authors.forename: Qian Qian
authors.initials: QQ
authors.lastname: Cai
authors.affiliation: Yu Ying Children's Hospital, Wenzhou Medical University, Wenzhou, PR. China.
authors.forename: Nian Hui
authors.initials: NH
authors.lastname: Deng
authors.affiliation: Yu Ying Children's Hospital, Wenzhou Medical University, Wenzhou, PR. China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.
authors.forename: Yu Tong
authors.initials: YT
authors.lastname: Jin
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, PR. China.|Key Laboratory of Glycoconjugate Research, Ministry of Public Health, Shanghai, PR. China.
authors.forename: Xing Zhong
authors.initials: XZ
authors.lastname: Wu
mesh_terms: D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000235:genetics* / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051419:Paxillin / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D013433:Sulfoglycosphingolipids / Q000378:metabolism / Q000494:pharmacology*; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D039302:Integrin alphaVbeta3; D051419:Paxillin; D013433:Sulfoglycosphingolipids; D014443:Tyrosine; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases
keywords: clustering; hepatocellular carcinoma; integrin; signaling; sulfated cerebroside