TY - JOUR
T1 - Mitochondrial membrane permeabilization is a critical step of lysosome-initiated apoptosis induced by hydroxychloroquine
AU - Boya, Patricia
AU - Gonzalez-Polo, Rosa Ana
AU - Poncet, Delphine
AU - Andreau, Karine
AU - Vieira, Helena L.A.
AU - Roumier, Thomas
AU - Perfettini, Jean Luc
AU - Kroemer, Guido
PY - 2003/6/19
Y1 - 2003/6/19
N2 - Hydroxychloroquine (HCQ) is a lysosomotropic amine with cytotoxic properties. Here, we show that HCQ induces signs of lysosomal membrane permeabilization (LMP), such as the decrease in the lysosomal pH gradient and the release of cathepsin B from the lysosomal lumen, followed by signs of apoptosis including caspase activation, phosphatidylserine exposure, and chromatin condensation with DNA loss. HCQ also induces mitochondrial membrane permeabilization (MMP), as indicated by the insertion of Bax into mitochondrial membranes, the conformational activation of Bax within mitochondria, the release of cytochrome c from mitochondria, and the loss of the mitochondrial transmembrane potential. To determine the molecular order among these events, we introduced inhibitors of LMP (bafilomycin A1), MMP (Bcl-XL, wild-type Bcl-2, mitochondrion-targeted Bcl-2, or viral mitochondrial inhibitor of apoptosis from cytomegalovirus), and caspases (Z-VAD.fmk) into the system. Our data indicate that caspase-independent MMP is rate-limiting for LMP-mediated caspase activation. Mouse embryonic fibroblasts lacking the expression of both Bax and Bak are resistant against hydroxychloroquine-induced apoptosis. Such Bax-/- Bak-/- cells manifest normal LMP, yet fail to undergo MMP and subsequent cell death. The data reported herein indicate that LMP does not suffice to trigger caspase activation and that Bax/Bak-dependent MMP is a critical step of LMP-induced cell death.
AB - Hydroxychloroquine (HCQ) is a lysosomotropic amine with cytotoxic properties. Here, we show that HCQ induces signs of lysosomal membrane permeabilization (LMP), such as the decrease in the lysosomal pH gradient and the release of cathepsin B from the lysosomal lumen, followed by signs of apoptosis including caspase activation, phosphatidylserine exposure, and chromatin condensation with DNA loss. HCQ also induces mitochondrial membrane permeabilization (MMP), as indicated by the insertion of Bax into mitochondrial membranes, the conformational activation of Bax within mitochondria, the release of cytochrome c from mitochondria, and the loss of the mitochondrial transmembrane potential. To determine the molecular order among these events, we introduced inhibitors of LMP (bafilomycin A1), MMP (Bcl-XL, wild-type Bcl-2, mitochondrion-targeted Bcl-2, or viral mitochondrial inhibitor of apoptosis from cytomegalovirus), and caspases (Z-VAD.fmk) into the system. Our data indicate that caspase-independent MMP is rate-limiting for LMP-mediated caspase activation. Mouse embryonic fibroblasts lacking the expression of both Bax and Bak are resistant against hydroxychloroquine-induced apoptosis. Such Bax-/- Bak-/- cells manifest normal LMP, yet fail to undergo MMP and subsequent cell death. The data reported herein indicate that LMP does not suffice to trigger caspase activation and that Bax/Bak-dependent MMP is a critical step of LMP-induced cell death.
KW - Bax
KW - Bcl-2
KW - Cell death
KW - Lysosomes
KW - Mitochondria
UR - http://www.scopus.com/inward/record.url?scp=0038677510&partnerID=8YFLogxK
U2 - 10.1038/sj.onc.1206622
DO - 10.1038/sj.onc.1206622
M3 - Article
C2 - 12813466
AN - SCOPUS:0038677510
SN - 0950-9232
VL - 22
SP - 3927
EP - 3936
JO - Oncogene
JF - Oncogene
IS - 25
ER -