Rapid induction of the intrinsic apoptotic pathway by L-glutamine starvation.
While the amino acid L-glutamine is known to play a role in the survival of several cell types, the underlying molecular mechanisms are still poorly defined. We show in this report that L-glutamine starvation rapidly triggered apoptosis in Sp2/0-Ag14 hybridoma cells. This process involved the activation of both caspases-9 and -3, suggesting that L-glutamine deprivation initiated an intrinsic apoptotic pathway in Sp2/0-Ag14 cells. Supporting this idea, the cytosolic release of the mitochondrial proteins SMAC/DIABLO and cytochrome c (Cyt c) was observed, with an initial limited leakage occurring during the first 30 min of L-glutamine deprivation, followed by a greater release after 60 min. The latter occurred simultaneously with the translocation of the pro-apoptotic protein Bax to the mitochondria. Finally, a decline in XIAP levels and the activation of caspases-3 and -9 were observed. Thus, L-glutamine deprivation of Sp2/0-Ag14 cells rapidly triggers intracellular events, which target the mitochondria, leading to the cytosolic release of apoptogenic factors, the activation of caspases-9 and -3, and the commitment to the death program. This work introduces the Sp2/0Ag14 hybridoma as a unique model for the study of the molecular events underlying the pro-survival function of L-glutamine.
Paquette
Julie C
JC
Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada.
Guérin
Paul J
PJ
Gauthier
Eric R
ER
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins; D045304:Cytochromes c / Q000378:metabolism; D015536:Down-Regulation; D004789:Enzyme Activation; D005973:Glutamine / Q000172:deficiency*; D006023:Glycoproteins / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051636:X-Linked Inhibitor of Apoptosis Protein; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; D015938:Complement Membrane Attack Complex; D006023:Glycoproteins; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C047610:SC5b-9 protein complex; D051636:X-Linked Inhibitor of Apoptosis Protein; D051028:bcl-2-Associated X Protein; D005973:Glutamine; D003165:Complement System Proteins; D045304:Cytochromes c; C505409:Casp3 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases