2-Deoxy-d-glucose cooperates with arsenic trioxide to induce apoptosis in leukemia cells: Involvement of IGF-1R-regulated Akt/mTOR, MEK/ERK and LKB-1/AMPK signaling pathways

9 páginas, 9 figuras, 2 figuras suplementarias -- PAGS nros. 1604-1616While the anti-tumor efficacy of 2-deoxy-d-glucose (2-DG) is normally low in monotherapy, it may represent a valuable radio- and chemo-sensitizing agent. We here demonstrate that 2–10 mM 2-DG cooperates with arsenic trioxide (ATO) and other antitumor drugs to induce apoptosis in human myeloid leukemia cell lines. Using ATO and HL60 as drug and cell models, respectively, we observed that 2-DG/ATO combination activates the mitochondrial apoptotic pathway, as indicated by Bid-, and Bax-regulated cytochrome c and Omi/HtrA2 release, XIAP down-regulation, and caspase-9/-3 pathway activation. 2-DG neither causes oxidative stress nor increases ATO uptake, but causes inner mitochondria membrane permeabilization as well as moderate ATP depletion, which nevertheless do not satisfactorily explain the pro-apoptotic response. Surprisingly 2-DG causes cell line-specific decrease in LKB-1/AMPK phosphorylation/activation, and also causes Akt/mTOR/p70S6K and MEK/ERK activation, which is prevented by co-treatment with ATO. The use of kinase-specific pharmacologic inhibitors and/or siRNAs reveals that apoptosis is facilitated by AMPK inactivation and restrained by Akt and ERK activation, and that Akt and ERK activation mediates AMPK inhibition. Finally, 2-DG stimulates IGF-1R phosphorylation/activation, and co-treatment with IGF-1R inhibitor prevents 2-DG effects on Akt, ERK and AMPK, and facilitates 2-DG-provoked apoptosis. In summary 2-DG elicits IGF-1R-mediated AMPK inactivation and Akt and ERK activation, which facilitates or restrain apoptosis, respectively. 2-DG-provoked AMPK inactivation increases the apoptotic efficacy of ATO, while in turn ATO-provoked Akt and ERK inactivation may increase the efficacy of 2-DG as anti-tumor drugThis work was supported by the Ministerio de Ciencia e Innovación, Spain, Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica, Dirección General de Investigación (Grant SAF2010-20256) and programa Consolider-Ingenio 2010 (Grant CSD2007-00020); and by the Consejo Superior de Investigaciones Científicas (Grant 201020E037). M.C.E. is recipient of a JAE-Predoc fellowship from de Consejo Superior de Investigaciones CientíficasThis work was supported by the Ministerio de Ciencia eInnovacio ́n, Spain, Plan Nacional de Investigacio ́n Cientı ́fica,Desarrollo e Innovacio ́n Tecnolo ́gica, Direccio ́n General deInvestigacio ́n (Grant SAF2010-20256) and programa Consolider-Ingenio 2010 (Grant CSD2007-00020); and by the Consejo Superiorde Investigaciones Cientı ́ficas (Grant 201020E037). M.C.E. isrecipient of a JAE-Predoc fellowship from de Consejo Superiorde Investigaciones Cientı ́ficas.Peer reviewe