title: Cell apoptosis induced by a synthetic carbazole compound LCY-2-CHO is mediated through activation of caspase and mitochondrial pathways.
abstract: The mechanisms involved in the apoptotic effect of LCY-2-CHO [9-(2-chlorobenzyl)-9H-carbazole-3-carbaldehyde], a synthetic carbazole derivative identified as an anti-inflammatory compound, were studied. Cell cycle analysis by propidium iodide staining in human THP-1 monocytic leukemia cells showed the ability of LCY-2-CHO to increase cell population in sub-G1 stage with time- and concentration-dependent manners. LCY-2-CHO-mediated cell death was also demonstrated by DNA laddering and was not related to the release of lactate dehydrogenase. Apoptosis in THP-1 cells induced by LCY-2-CHO was accompanied by the Bid cleavage, collapse of mitochondrial transmembrane potential, the release of cytochrome c and the activation of caspase-3. The apoptotic effect of LCY-2-CHO was diminished by the presence of zVEID-fmk (caspase-6 inhibitor), zIETD-fmk (caspase-8 inhibitor), and zVAD-fmk (non-selective caspase inhibitor), but was not altered by several antioxidants, and cathepsin inhibitor. The Bid cleavage and loss of mitochondrial transmembrane potential, but not the cytochrome c release, were reversed by zIETD-fmk. Comparing the cell selectivity of LCY-2-CHO, we found T-cell acute lymphoblastic CEM leukemia cells were sensitive to 1 microM LCY-2-CHO, acute myeloid leukemia HL-60 cells underwent apoptosis at 10 microM, while adherent cancer cells, such as PC3, HT29 and MCF-7, were resistant to 30 microM LCY-2-CHO within 24-h incubation. Taken together in the present study, we demonstrated LCY-2-CHO might be apoptotic for malignant hematopoietic cells but not anchorage-dependent cells. This action is mediated by an intrinsic caspase-dependent apoptotic event involving mitochondria.
authors.affiliation: Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Ming-Jen
authors.initials: MJ
authors.lastname: Hsu
authors.forename: Yee
authors.initials: Y
authors.lastname: Chao
authors.forename: Ying-Hsin
authors.initials: YH
authors.lastname: Chang
authors.forename: Feng-Ming
authors.initials: FM
authors.lastname: Ho
authors.forename: Li-Jiau
authors.initials: LJ
authors.lastname: Huang
authors.forename: Ya-Ling
authors.initials: YL
authors.lastname: Huang
authors.forename: Tien-Yau
authors.initials: TY
authors.lastname: Luh
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chen
authors.forename: Wan-Wan
authors.initials: WW
authors.lastname: Lin
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002227:Carbazoles / Q000494:pharmacology*; D020169:Caspases / Q000502:physiology*; D002403:Cathepsins / Q000502:physiology; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D017382:Reactive Oxygen Species
chemical_list: C499102:9-(2-chlorobenzyl)-9H-carbazole-3-carbaldehyde; D000893:Anti-Inflammatory Agents; D002227:Carbazoles; D017382:Reactive Oxygen Species; D045304:Cytochromes c; D002403:Cathepsins; D020169:Caspases