title: Aspirin acetylates wild type and mutant p53 in colon cancer cells: identification of aspirin acetylated sites on recombinant p53.
abstract: Aspirin's ability to inhibit cell proliferation and induce apoptosis in cancer cell lines is considered to be an important mechanism for its anti-cancer effects. We previously demonstrated that aspirin acetylated the tumor suppressor protein p53 at lysine 382 in MDA-MB-231 human breast cancer cells. Here, we extended these observations to human colon cancer cells, HCT 116 harboring wild type p53, and HT-29 containing mutant p53. We demonstrate that aspirin induced acetylation of p53 in both cell lines in a concentration-dependent manner. Aspirin-acetylated p53 was localized to the nucleus. In both cell lines, aspirin induced p21(CIP1). Aspirin also acetylated recombinant p53 (rp53) in vitro suggesting that it occurs through a non-enzymatic chemical reaction. Mass spectrometry analysis and immunoblotting identified 10 acetylated lysines on rp53, and molecular modeling showed that all lysines targeted by aspirin are surface exposed. Five of these lysines are localized to the DNA-binding domain, four to the nuclear localization signal domain, and one to the C-terminal regulatory domain. Our results suggest that aspirin's anti-cancer effect may involve acetylation and activation of wild type and mutant p53 and induction of target gene expression. This is the first report attempting to characterize p53 acetylation sites targeted by aspirin.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Avera Health and Sciences Center, South Dakota State University, Brookings, SD, USA.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Ai
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Avera Health and Sciences Center, South Dakota State University, Brookings, SD, USA.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Dachineni
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Avera Health and Sciences Center, South Dakota State University, Brookings, SD, USA.
authors.forename: D Ramesh
authors.initials: DR
authors.lastname: Kumar
authors.affiliation: Ayurveda Research Institute for Mother & Child Health Care, Poojapura, Trivandrum, Kerala, India.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Marimuthu
authors.affiliation: School of Pharmacy, D'Youville College, 320 Porter Avenue, Buffalo, NY, 14201, USA.
authors.forename: Lloyd F
authors.initials: LF
authors.lastname: Alfonso
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Avera Health and Sciences Center, South Dakota State University, Brookings, SD, USA. Jayarama.gunaje@sdstate.edu.
authors.forename: G Jayarama
authors.initials: GJ
authors.lastname: Bhat
mesh_terms: D000107:Acetylation / Q000187:drug effects; D001241:Aspirin / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D008239:Lysine / Q000378:metabolism; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D050505:Mutant Proteins; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D008239:Lysine; D001241:Aspirin
keywords: Acetylation; Anti-cancer effects; Apoptosis; Aspirin; p53