title: Regulation of plasminogen activator inhibitor-1 expression by tumor suppressor protein p53.
abstract: H1299 lung carcinoma cells lacking p53 (p53-/-) express minimal amounts of plasminogen activator inhibitor-1 (PAI-1) protein as well as mRNA. p53(-/-) cells express highly unstable PAI-1 mRNA. Transfection of p53 in p53(-/-) cells enhanced PAI-1 expression and stabilized PAI-1 mRNA. On the contrary, inhibition of p53 expression by RNA silencing in non-malignant human lung epithelial (Beas2B) cells decreased basal as well as urokinase-type plasminogen activator-induced PAI-1 expression because of accelerated degradation of PAI-1 mRNA. Purified p53 protein specifically binds to the PAI-1 mRNA 3'-un-translated region (UTR), and endogenous PAI-1 mRNA forms an immune complex with p53. Treatment of purified p53 protein with anti-p53 antibody abolished p53 binding to the 3'-UTR of PAI-1 mRNA. The p53 binding region maps to a 70-nucleotide PAI-1 mRNA 3'-UTR sequence, and insertion of the p53-binding sequence into beta-globin mRNA destabilized the chimeric transcript. Deletion experiments indicate that the carboxyl-terminal region (amino acid residues 296-393) of p53 protein interacts with PAI-1 mRNA. These observations demonstrate a novel role for p53 as an mRNA-binding protein that regulates increased PAI-1 expression and stabilization of PAI-1 mRNA in human lung epithelial and carcinoma cells.
authors.affiliation: Texas Lung Injury Institute, University of Texas Health Center, Tyler, Texas 75708, USA. sreerama.shetty@uthct.edu
authors.forename: Sreerama
authors.initials: S
authors.lastname: Shetty
authors.forename: Praveenkumar
authors.initials: P
authors.lastname: Shetty
authors.forename: Steven
authors.initials: S
authors.lastname: Idell
authors.forename: Thirunavukkarasu
authors.initials: T
authors.lastname: Velusamy
authors.forename: Yashodhar P
authors.initials: YP
authors.lastname: Bhandary
authors.forename: Rashmi S
authors.initials: RS
authors.lastname: Shetty
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D005914:Globins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis* / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D020871:RNA Stability / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; D017395:Plasminogen Activator Inhibitor 1; D012334:RNA, Neoplasm; C051321:SERPINE1 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D005914:Globins