Abstract 1638: Aspirin acetylates multiple cellular proteins in HCT-116 cells: Identification of novel targets

Abstract

Abstract Aspirin, a non-steroidal anti-inflammatory drug has been consistently associated with a reduced risk of colon cancer; however, the molecular mechanisms are not completely understood. In the present study, we determined the ability of aspirin to acetylate, and post-transnationally modify cellular proteins in HCT-116 human cancer cells to understand the potential mechanisms by which it may exert anti-cancer effects. Using anti-acetyl lysine antibodies, here we demonstrate that aspirin causes the acetylation of multiple proteins whose molecular weight ranged from 20 to 200 kDa. The identity of these proteins was determined, using immune-affinity purification, mass spectrometry and immunoblotting. A total of 33 cellular proteins were potential targets of aspirin-mediated acetylation, while 16 were identified as common to both the control and aspirin-treated samples. These include enzymes of glycolytic pathway, cytoskeletal proteins, histones, ribosomal and mitochondrial proteins. The glycolytic enzymes which were identified include aldolase, glyceraldehyde 3 phosphate dehydrogenase, enolase, pyruvate kinase M2, and lactate dehydrogenase A and B chains. Immunoblotting experiments showed that aspirin also acetylated glucose 6-phosphate dehydrogenase and transketolase, both enzymes of pentose phosphate pathway involved in ribonucleotide biosynthesis. In vitro assays of these enzymes revealed that aspirin did not affect pyruvate kinase and lactate dehydrogenase activity; however, it decreased glucose 6-phosphate dehydrogenase activity. Selective inhibition of glucose 6-phosphate dehydrogenase and other key proteins through acetylation may represent important mechanisms by which aspirin may exert its anti-cancer effects. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1638. doi:1538-7445.AM2012-1638