Abstract 1579: Depletion of GAPDH promotes p53 signaling, cell senescence and altered response to chemotherapeutic agents in human carcinoma cells

Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a pivotal enzyme of the glycolytic pathway; it also plays a role of a signaling/regulator molecule in several cellular networks. In this study, we used human lung carcinoma A549 and renal carcinoma UO-31 cell lines to elucidate the role of GAPDH in cell proliferation and cellular response to genotoxic drugs. Using RNA interference technology, we decreased GAPDH protein level 4-5-fold in A549 cells, and 2-3-fold in UO-31 cells. Depletion of GAPDH in cultured cells blocked cell cycle progression in G1 phase, and induced activation of p53 and accumulation of p21. Simultaneously, GAPDH-depleted cells manifested biomarkers of senescence as revealed by morphological changes and induction of SA-β-galactosidase activity. Inhibition of GAPDH synthesis in human carcinoma cells resulted in 3-4-fold ATP depletion, and induced cell growth arrest without AMPK phosphorylation. In contrast, inhibition of glycolysis by 2-deoxyglucose treatment resulted in decreased ATP level and AMPK phosphorylation but did not induce cell senescence. These results suggest that GAPDH depletion in A549 cell line activates p53 independently of AMPK activation, and mediates the induction of signaling pathways leading to senescence. Importantly, GAPDH knockdown in p53-proficient A549 and UO-31 cells resulted in 3-50-fold decreased cytotoxicity of antimetabolite drugs including deoxy-thioguanosine, cladribine, fluoro-ribouridine, fluoruracil, 2-chloroadenosine, mercaptopurine, azacytidine and cytarabine. The results of this study indicate that cytotoxic activity of antimetabolite nucleoside analogs is modulated by the status of GAPDH in the cancer cells. Cell senescence induced by depletion of GAPDH is a plausible mechanism of cell resistance to antimetabolites, a hypothesis being under investigation in our lab. In addition, our data indicate that GAPDH-depleting agents could be promising cytostatic drugs. This work was supported by NCI grant R01 CA104729 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1579.