title: EF1A1-actin interactions alter mRNA stability to determine differential osteopontin expression in HepG2 and Hep3B cells.
abstract: Cancer progression depends on an accumulation of metastasis-supporting physiological changes which are regulated by cell signaling molecules. One such molecule, osteopontin (OPN), is a secreted phosphoprotein which mediates increased cellular migratory and invasive behavior, increased metastasis, protection from apoptosis, promotion of colony formation and 3D growth ability, induction of tumor-associated inflammatory cells, and induction of expression of angiogenic factors. Studies show that OPN expression is controlled by complex regulatory pathways at the transcriptional level in several cancers, but the molecular mechanisms which determine expression of OPN in HCC are largely unknown. In HepG2 and Hep3B tumor cell lines that differentially express OPN mRNA and protein, we identify elongation translation factor-1A1 (EF1A1) to be the trans-acting factor regulating differential OPN mRNA stability between HepG2 and Hep3B cell lines and characterize its interactions with G- and F-actin. EF1A1 binds to the OPN 5'-UTR to regulate OPN mRNA half-life. EF1A1 binds to actin in Hep3B cells. Pharmacologic manipulation to increase the G:F actin ratio in Hep3B increases OPN mRNA half-life and protein expression with simultaneous decrease in EF1A1 binding to OPN 5'-UTR. The converse findings were noted in HepG2 cells. Overall, our results suggest that EF1A1 regulation of OPN mRNA stability is actin dependent. EF1A1 has not been previously identified as a regulatory factor in OPN expression in cancer.
authors.affiliation: Department of Surgery, 110 Bell Building, Duke University Medical Center, Box 3522, Durham, NC 27710, USA.
authors.forename: Jinping
authors.initials: J
authors.lastname: Zhang
authors.forename: Hongtao
authors.initials: H
authors.lastname: Guo
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Mi
authors.forename: Chengjiang
authors.initials: C
authors.lastname: Gao
authors.forename: Syamal
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Li
authors.forename: Paul C
authors.initials: PC
authors.lastname: Kuo
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D003603:Cytotoxins / Q000494:pharmacology; D047630:Depsipeptides / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008387:Marine Toxins / Q000494:pharmacology; D053495:Osteopontin / Q000235:genetics* / Q000378:metabolism; D020648:Peptide Elongation Factor 1 / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000235:genetics; D050436:Regulatory Elements, Transcriptional / Q000235:genetics; D017384:Sequence Deletion; D014162:Transfection
chemical_list: D020121:5' Untranslated Regions; D000199:Actins; D000970:Antineoplastic Agents; D003603:Cytotoxins; D047630:Depsipeptides; C094814:EEF1A1 protein, human; D008387:Marine Toxins; D020648:Peptide Elongation Factor 1; D034741:RNA, Small Interfering; C057531:jasplakinolide; D053495:Osteopontin; C086235:swinholide A