TY - JOUR
T1 - 9-Norbornyl-6-chloropurine (NCP) induces cell death through GSH depletion-associated ER stress and mitochondrial dysfunction
AU - Plačková, Pavla
AU - Šála, Michal
AU - Šmídková, Markéta
AU - Dejmek, Milan
AU - Hřebabecký, Hubert
AU - Nencka, Radim
AU - Thibaut, Hendrik-Jan
AU - Neyts, Johan
AU - Mertlíková-Kaiserová, Helena
N1 - Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
PY - 2016/6/7
Y1 - 2016/6/7
N2 - 9-Norbornyl-6-chloropurine (NCP) is a representative of a series of antienteroviral bicycle derivatives with selective cytotoxicity towards leukemia cell lines. In this work we explored the mechanism of the antileukemic activity of NCP in T-cell lymphoblast cells (CCRF-CEM). Specifically, we searched for a potential link between its ability to induce cell death on the one hand and to modulate intracellular glutathione (GSH) that is necessary to its metabolic transformation via glutathione-S-transferase on the other hand. We have observed that GSH levels decreased rapidly in NCP-treated cells. Despite a complete regeneration following 24h of incubation with NCP, this profound drop in cellular GSH content triggered ER stress, ROS production and lipid peroxidation leading to the loss of mitochondrial membrane potential (MMP). These events induced concentration-dependent cell cycle arrest in G2/M phase and apoptosis. Both MMP loss and apoptosis were reversed by sulfhydryl-containing compounds (GSH, N-acetyl-l-cysteine). Furthermore, we have also shown that NCP-induced GSH decrease activated the Nrf2 pathway and its downstream targets NAD(P)H:quinone oxidoreductase (NQO-1) and glutamate cysteine ligase modifier subunit (GCLm), thus explaining the fast restoration of GSH pool and ROS decrease. Importantly, we confirmed that the cell death-inducing properties of the compounds were co-dependent on their ability to diminish cellular GSH level by analyzing the relationships between the GSH-depleting potency and cytotoxicity in a series of other norbornylpurine analogs. Altogether, the results demonstrated that in CCRF-CEM cells NCP triggered apoptosis through GSH depletion-associated oxidative and ER stress and mitochondrial depolarization.
AB - 9-Norbornyl-6-chloropurine (NCP) is a representative of a series of antienteroviral bicycle derivatives with selective cytotoxicity towards leukemia cell lines. In this work we explored the mechanism of the antileukemic activity of NCP in T-cell lymphoblast cells (CCRF-CEM). Specifically, we searched for a potential link between its ability to induce cell death on the one hand and to modulate intracellular glutathione (GSH) that is necessary to its metabolic transformation via glutathione-S-transferase on the other hand. We have observed that GSH levels decreased rapidly in NCP-treated cells. Despite a complete regeneration following 24h of incubation with NCP, this profound drop in cellular GSH content triggered ER stress, ROS production and lipid peroxidation leading to the loss of mitochondrial membrane potential (MMP). These events induced concentration-dependent cell cycle arrest in G2/M phase and apoptosis. Both MMP loss and apoptosis were reversed by sulfhydryl-containing compounds (GSH, N-acetyl-l-cysteine). Furthermore, we have also shown that NCP-induced GSH decrease activated the Nrf2 pathway and its downstream targets NAD(P)H:quinone oxidoreductase (NQO-1) and glutamate cysteine ligase modifier subunit (GCLm), thus explaining the fast restoration of GSH pool and ROS decrease. Importantly, we confirmed that the cell death-inducing properties of the compounds were co-dependent on their ability to diminish cellular GSH level by analyzing the relationships between the GSH-depleting potency and cytotoxicity in a series of other norbornylpurine analogs. Altogether, the results demonstrated that in CCRF-CEM cells NCP triggered apoptosis through GSH depletion-associated oxidative and ER stress and mitochondrial depolarization.
KW - Norbornylpurines
KW - Glutathione
KW - Apoptosis
KW - Unfolded protein response
KW - Mitochondrial membrane potential
KW - Reactive oxygen species
KW - Nrf-2
U2 - 10.1016/j.freeradbiomed.2016.06.004
DO - 10.1016/j.freeradbiomed.2016.06.004
M3 - Article
C2 - 27288283
SN - 0891-5849
VL - 97
SP - 223
EP - 235
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
ER -