Amino acid starvation induced autophagic cell death in PC-12 cells: evidence for activation of caspase-3 but not calpain-1.
While the apoptotic and necrotic cell death pathways have been well studied, there lacks a comprehensive understanding of the molecular events involving autophagic cell death. We examined the potential roles of the apoptosis-linked caspase-3 and the necrosis/apoptosis-linked calpain-1 after autophagy induction under prolonged amino acid (AA) starvation conditions in PC-12 cells. Autophagy induction was observed as early as three hours following amino acid withdrawal. Cell death, measured by lactate dehydrogenase (LDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays occurred within 24 h following starvation and was accompanied by an upregulation in caspase-3 activity but not calpain-1. The cell death that occurred following AA starvation was significantly alleviated by treatment with the autophagy inhibitor 3-methyl adenine but not with the broad spectrum caspase inhibitors. Thus, this study demonstrates that 3-methyladenine-sensitive autophagic cell death due to AA starvation in PC-12 cells is mechanistically and biochemically similar to, yet distinct from, classic caspase dependent apoptosis.
Sadasivan
Shankar
S
Department of Neuroscience, Center for Traumatic Brain Injury Studies, McKnight Brain Institute of the University of Florida, Gainesville, USA.
Waghray
Anu
A
Larner
Stephen F
SF
Dunn
William A
WA
Hayes
Ronald L
RL
Wang
Kevin K W
KK
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001343:Autophagy / Q000502:physiology*; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism*; D061945:Caspase Inhibitors; D002403:Cathepsins / Q000378:metabolism; D002467:Cell Nucleus / Q000648:ultrastructure; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051381:Rats; D013049:Spectrin / Q000378:metabolism; D013217:Starvation / Q000378:metabolism*; D013995:Time; D014407:Tumor Cells, Cultured
D000596:Amino Acids; D061945:Caspase Inhibitors; D013049:Spectrin; D007770:L-Lactate Dehydrogenase; D002403:Cathepsins; D002154:Calpain; D053148:Caspase 3