title: Capsaicin-induced apoptosis is regulated by endoplasmic reticulum stress- and calpain-mediated mitochondrial cell death pathways.
abstract: Capsaicin, a pungent compound found in hot chili peppers, induces apoptotic cell death in various cell lines, however, the precise apoptosis signaling pathway is unknown. Here, we investigated capsaicin-induced apoptotic signaling in the human breast cell line MCF10A and found that it involves both endoplasmic reticulum (ER) stress and calpain activation. Capsaicin inhibited growth in a dose-dependent manner and induced apoptotic nuclear changes in MCF10A cells. Capsaicin also induced degradation of tumor suppressor p53; this effect was enhanced by the ER stressor tunicamycin. The proteasome inhibitor MG132 completely blocked capsaicin-induced p53 degradation and enhanced apoptotic cell death. Capsaicin treatment triggered ER stress by increasing levels of IRE1, GADD153/Chop, GRP78/Bip, and activated caspase-4. It led to an increase in cytosolic Ca(2+), calpain activation, loss of the mitochondrial transmembrane potential, release of mitochondrial cytochrome c, and caspase-9 and -7 activation. Furthermore, capsaicin-induced the mitochondrial apoptotic pathway through calpain-mediated Bid translocation to the mitochondria and nuclear translocation of apoptosis-inducing factor (AIF). Capsaicin-induced caspase-9, Bid cleavage, and AIF translocation were blocked by calpeptin, and BAPTA and calpeptin attenuated calpain activation and Bid cleavage. Thus, both ER stress- and mitochondria-mediated death pathways are involved in capsaicin-induced apoptosis.
authors.affiliation: Department of Pathology, College of Medicine, Chosun University, Dong-Gu, Gwangju, Republic of Korea.
authors.forename: Mi-Ja
authors.initials: MJ
authors.lastname: Lee
authors.forename: Keun-Hong
authors.initials: KH
authors.lastname: Kee
authors.forename: Chae-Hong
authors.initials: CH
authors.lastname: Suh
authors.forename: Sung-Chul
authors.initials: SC
authors.lastname: Lim
authors.forename: Seon-Hee
authors.initials: SH
authors.lastname: Oh
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002154:Calpain / Q000378:metabolism*; D002211:Capsaicin / Q000633:toxicity*; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D000091342:Endoplasmic Reticulum Chaperone BiP; D004722:Endoribonucleases / Q000378:metabolism; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D015398:Signal Transduction / Q000187:drug effects*; D013312:Stress, Physiological / Q000187:drug effects*; D013997:Time Factors; D051742:Transcription Factor CHOP / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: C494829:AIFM1 protein, human; D051033:Apoptosis Inducing Factor; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D015853:Cysteine Proteinase Inhibitors; C497249:DDIT3 protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D007976:Leupeptins; D008565:Membrane Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D014415:Tunicamycin; D051742:Transcription Factor CHOP; D045304:Cytochromes c; C403982:ERN2 protein, human; D017346:Protein Serine-Threonine Kinases; D004722:Endoribonucleases; D002154:Calpain; D020169:Caspases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D002211:Capsaicin