TY - JOUR
T1 - Dual mechanisms of sHA 14-1 in inducing cell death through endoplasmic reticulum and mitochondria
AU - Hermanson, David
AU - Addo, Sadiya N.
AU - Bajer, Anna A.
AU - Marchant, Jonathan S.
AU - Das, Sonia Goutam Kumar
AU - Srinivasan, Balasubramanian
AU - Al-Mousa, Fawaz
AU - Michelangeli, Francesco
AU - Thomas, David D.
AU - LeBien, Tucker W.
AU - Xing, Chengguo
PY - 2009/9
Y1 - 2009/9
N2 - HA 14-1 is a small-molecule Bcl-2 antagonist that promotes apoptosis in malignant cells, but its mechanism of action is not well defined. We recently reported that HA 14-1 has a half-life of only 15 min in vitro, which led us to develop a stable analog of HA 14-1 (sHA 14-1). The current study characterizes its mode of action. Because of the antiapoptotic function of Bcl-2 family proteins on the endoplasmic reticulum (ER) and mitochondria, the effect of sHA 14-1 on both organelles was evaluated. sHA 14-1 induced ER calcium release in human leukemic cells within 1 min, followed by induction of the ER stress-inducible transcription factor ATF4. Similar kinetics and stronger intensity of ER calcium release were induced by the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor thapsigargin, accompanied by similar kinetics and intensity of ATF4 induction. sHA 14-1 directly inhibited SERCA enzymatic activity but had no effect on the inositol triphosphate receptor. Evaluation of the mitochondrial pathway showed that sHA 14-1 triggered a loss of mitochondrial transmembrane potential (Δψm) and weak caspase-9 activation, whereas thapsigargin had no effect. (R)-4-(3-Dimethylamino-1- phenylsulfanylmethylpropylamino)-N-{4-[4-(4′-chloro-biphenyl-2-ylmethyl) -piperazin-1-yl]-benzoyl}-3-nitrobenzenesulfonamide (ABT-737), a well established small-molecule Bcl-2 antagonist, rapidly induced loss of Δψm and caspase-9 activation but had no effect on the ER. The pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone had some protective effect on sHA 14-1-induced cell death. These collective results suggest a unique dual targeting mechanism of sHA 14-1 on the apoptotic resistance machinery of tumor cells that includes antiapoptotic Bcl-2 family proteins and SERCA proteins.
AB - HA 14-1 is a small-molecule Bcl-2 antagonist that promotes apoptosis in malignant cells, but its mechanism of action is not well defined. We recently reported that HA 14-1 has a half-life of only 15 min in vitro, which led us to develop a stable analog of HA 14-1 (sHA 14-1). The current study characterizes its mode of action. Because of the antiapoptotic function of Bcl-2 family proteins on the endoplasmic reticulum (ER) and mitochondria, the effect of sHA 14-1 on both organelles was evaluated. sHA 14-1 induced ER calcium release in human leukemic cells within 1 min, followed by induction of the ER stress-inducible transcription factor ATF4. Similar kinetics and stronger intensity of ER calcium release were induced by the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor thapsigargin, accompanied by similar kinetics and intensity of ATF4 induction. sHA 14-1 directly inhibited SERCA enzymatic activity but had no effect on the inositol triphosphate receptor. Evaluation of the mitochondrial pathway showed that sHA 14-1 triggered a loss of mitochondrial transmembrane potential (Δψm) and weak caspase-9 activation, whereas thapsigargin had no effect. (R)-4-(3-Dimethylamino-1- phenylsulfanylmethylpropylamino)-N-{4-[4-(4′-chloro-biphenyl-2-ylmethyl) -piperazin-1-yl]-benzoyl}-3-nitrobenzenesulfonamide (ABT-737), a well established small-molecule Bcl-2 antagonist, rapidly induced loss of Δψm and caspase-9 activation but had no effect on the ER. The pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone had some protective effect on sHA 14-1-induced cell death. These collective results suggest a unique dual targeting mechanism of sHA 14-1 on the apoptotic resistance machinery of tumor cells that includes antiapoptotic Bcl-2 family proteins and SERCA proteins.
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U2 - 10.1124/mol.109.055830
DO - 10.1124/mol.109.055830
M3 - Article
C2 - 19561125
AN - SCOPUS:69549124714
VL - 76
SP - 667
EP - 678
JO - Molecular Pharmacology
JF - Molecular Pharmacology
SN - 0026-895X
IS - 3
ER -