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N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells.
Toxicol Appl Pharmacol. 2009 Aug 15; 239(1):87-97.TA

Abstract

N,N-dimethyl phytosphingosine (DMPS) blocks the conversion of sphingosine to sphingosine-1-phosphate (S1P) by the enzyme sphingosine kinase (SK). In this study, we elucidated the apoptotic mechanisms of DMPS action on a human leukemia cell line using functional pharmacologic and genetic approaches. First, we demonstrated that DMPS-induced apoptosis is evidenced by nuclear morphological change, distinct internucleosomal DNA fragmentation, and an increased sub-G1 cell population. DMPS treatment led to the activation of caspase-9 and caspase-3, accompanied by the cleavage of poly(ADP-ribose) polymerase (PARP) and led to cytochrome c release, depolarization of the mitochondrial membrane potential, and downregulation of the anti-apoptotic members of the bcl-2 family. Ectopic expression of bcl-2 and bcl-xL conferred resistance of HL-60 cells to DMPS-induced cell death, suggesting that DMPS-induced apoptosis occurs predominantly through the activation of the intrinsic mitochondrial pathway. We also observed that DMPS activated the caspase-8-Bid-Bax pathway and that the inhibition of caspase-8 by z-IETD-fmk or small interfering RNA suppressed the cleavage of Bid, cytochrome c release, caspase-3 activation, and apoptotic cell death. In addition, cells subjected to DMPS exhibited significantly increased reactive oxygen species (ROS) generation, and ROS scavengers, such as quercetin and Tiron, but not N-acetylcysteine (NAC), inhibited DMPS-induced activations of caspase-8, -3 and subsequent apoptotic cell death, indicating the role of ROS in caspase-8-mediated apoptosis. Taken together, these results indicate that caspase-8 acts upstream of caspase-3, and that the caspase-8-mediated mitochondrial pathway is important in DMPS-induced apoptosis. Our results also suggest that ROS are critical regulators of caspase-8-mediated apoptosis in DMPS-treated leukemia cells.

Authors+Show Affiliations

Korea Institute of Radiological and Medical Sciences, Gongneung-Dong, Nowon-Gu, Seoul, Republic of Korea.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19481559

Citation

Kim, Byeong Mo, et al. "N,N-dimethyl Phytosphingosine Induces Caspase-8-dependent Cytochrome C Release and Apoptosis Through ROS Generation in Human Leukemia Cells." Toxicology and Applied Pharmacology, vol. 239, no. 1, 2009, pp. 87-97.
Kim BM, Choi YJ, Han Y, et al. N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells. Toxicol Appl Pharmacol. 2009;239(1):87-97.
Kim, B. M., Choi, Y. J., Han, Y., Yun, Y. S., & Hong, S. H. (2009). N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells. Toxicology and Applied Pharmacology, 239(1), 87-97. https://doi.org/10.1016/j.taap.2009.05.020
Kim BM, et al. N,N-dimethyl Phytosphingosine Induces Caspase-8-dependent Cytochrome C Release and Apoptosis Through ROS Generation in Human Leukemia Cells. Toxicol Appl Pharmacol. 2009 Aug 15;239(1):87-97. PubMed PMID: 19481559.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells. AU - Kim,Byeong Mo, AU - Choi,Yun Jung, AU - Han,Youngsoo, AU - Yun,Yeon-Sook, AU - Hong,Sung Hee, Y1 - 2009/05/28/ PY - 2009/02/24/received PY - 2009/05/06/revised PY - 2009/05/20/accepted PY - 2009/6/2/entrez PY - 2009/6/2/pubmed PY - 2009/8/12/medline SP - 87 EP - 97 JF - Toxicology and applied pharmacology JO - Toxicol. Appl. Pharmacol. VL - 239 IS - 1 N2 - N,N-dimethyl phytosphingosine (DMPS) blocks the conversion of sphingosine to sphingosine-1-phosphate (S1P) by the enzyme sphingosine kinase (SK). In this study, we elucidated the apoptotic mechanisms of DMPS action on a human leukemia cell line using functional pharmacologic and genetic approaches. First, we demonstrated that DMPS-induced apoptosis is evidenced by nuclear morphological change, distinct internucleosomal DNA fragmentation, and an increased sub-G1 cell population. DMPS treatment led to the activation of caspase-9 and caspase-3, accompanied by the cleavage of poly(ADP-ribose) polymerase (PARP) and led to cytochrome c release, depolarization of the mitochondrial membrane potential, and downregulation of the anti-apoptotic members of the bcl-2 family. Ectopic expression of bcl-2 and bcl-xL conferred resistance of HL-60 cells to DMPS-induced cell death, suggesting that DMPS-induced apoptosis occurs predominantly through the activation of the intrinsic mitochondrial pathway. We also observed that DMPS activated the caspase-8-Bid-Bax pathway and that the inhibition of caspase-8 by z-IETD-fmk or small interfering RNA suppressed the cleavage of Bid, cytochrome c release, caspase-3 activation, and apoptotic cell death. In addition, cells subjected to DMPS exhibited significantly increased reactive oxygen species (ROS) generation, and ROS scavengers, such as quercetin and Tiron, but not N-acetylcysteine (NAC), inhibited DMPS-induced activations of caspase-8, -3 and subsequent apoptotic cell death, indicating the role of ROS in caspase-8-mediated apoptosis. Taken together, these results indicate that caspase-8 acts upstream of caspase-3, and that the caspase-8-mediated mitochondrial pathway is important in DMPS-induced apoptosis. Our results also suggest that ROS are critical regulators of caspase-8-mediated apoptosis in DMPS-treated leukemia cells. SN - 1096-0333 UR - https://www.unboundmedicine.com/medline/citation/19481559/NN_dimethyl_phytosphingosine_induces_caspase_8_dependent_cytochrome_c_release_and_apoptosis_through_ROS_generation_in_human_leukemia_cells_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0041-008X(09)00219-1 DB - PRIME DP - Unbound Medicine ER -