Apoptosis to necrosis switching downstream of apoptosome formation requires inhibition of both glycolysis and oxidative phosphorylation in a BCL-XL- and PKB/AKT-independent fashion

Abstract

Human T-lymphoma Jurkat cells treated with several intrinsic death stimuli readily undergo a stepwise apoptotic program. Treatment with 1,9-dideoxyforskolin (ddFSK), an inactive analogue of the adenylate cyclase activator forskolin, induces necrotic cell death and switches to necrosis the response to the apoptosis inducers in Jurkat and in other cell models. Yet, in the presence of ddFSK, mitochondrial changes are enhanced and apoptosome formation takes place. We show that ddFSK does not inhibit the catabolic steps of apoptosis, but rather elicits a profound ATP depletion that in turn tunes the mode of cell demise towards necrosis. Treatment with ddFSK impairs both glycolysis and oxidative phosphorylation in a Bcl-X L -and PKB/Akt-independent fashion, and inhibition of both processes is needed to affect apoptosis progression. Apoptosis is not blocked per se by ATP depletion, as engagement of the Fas receptor directly activates caspases, thus bypassing ddFSK inhibition. Keywords: apoptosis; necrosis; PKB/Akt; Bcl-X L ; 1,9-dideoxyforskolin; energy metabolism Abbreviations: AIF, apoptosis-inducing factor; Anis, anisomycin; ANT, antimycin A; CCCP, carbonil cyanide m-chlorophenylhydrazone; CPT, camptothecin; cyt c, cytochrome c; DAPI, 4 0 ,6-diamidino-2-phenylindole; ddFSK, 1,9-dideoxyforskolin; 2DG, 2-deoxyglucose; Dc m , mitochondrial electrochemical gradient; ETO, etoposide; FCCP, carbonyl cyanide 4-trifluoromethoxyphenyl-hydrazone; GSK3, glycerol synthase kinase 3; MAN, mannitol; PARP, poly (ADP-ribose) polymerase; PCD, programmed cell death; PI, propidium iodide; ROT, rotenone; Smac/DIABLO, second mitochondrial-released activator of caspases/direct IAPbinding protein with a low isoelectric point; STS, staurosporine; TMRM, tetramethylrhodamine methyl ester; 5TG, 5-thyoglucose; TUNEL, TdT-mediated dUTP-X nick end labeling

Desensitization of the Permeability Transition Pore by Cyclosporin A Prevents Activation of the Mitochondrial Apoptotic Pathway and Liver Damage by Tumor Necrosis Factor-α

“…On the other hand, openings of long duration would cause matrix swelling with outer membrane rupture, depletion of pyridine nucleotides with respiratory inhibition, irreversible depolarization, and mitochondrial hydrolysis of ATP (49). The resulting ATP depletion would prevent activation of caspase 9 and switch cell death to a different subroutine (50,51), where caspase-independent events may predominate (48). Thus, a continuum of modes of cell death is possible that is consistent with the spectrum of morphological changes recorded by histology.…”

Glycogen Synthase Kinase 3β Regulates Cell Death Induced by Synthetic Triterpenoids

“…Taken together, these data suggest that GSK3 helps bring to its limit the apoptotic potential in prostate cancer cells, thus modulating the threshold of sensitivity to CDDO-Me and possibly contributing to the molecular mechanism that regulates a dose-and time-dependent apoptosis-necrosis switch (36,39,42,(46)(47)(48).…”

A Small-Molecule Inhibitor of Glucose Transporter 1 Downregulates Glycolysis, Induces Cell-Cycle Arrest, and Inhibits Cancer Cell Growth In Vitro and In Vivo

“…All these changes culminated in cellcycle arrest, accompanied by senescence and upregulation of some glycolytic enzymes, which is likely to be a response to senescence (52). Prolonged inhibition of glucose transport and reduction of glycolysis induced necrosis (19,53), further inhibiting cancer cell growth. Cell-cycle G 1 arrest, mediated by downregulation of cyclin E2 and phosphorylation of Rb, and subsequent senescence and necrosis were the major mechanisms underlying the inhibitory action of WZB117 on cancer cell growth.…”