title: Involvement of endoplasmic reticulum stress and activation of MAP kinases in beta-lapachone-induced human prostate cancer cell apoptosis.
abstract: Beta-lapachone, an o-naphthoquinone, induces various carcinoma cells to undergo apoptosis, but the mechanism is poorly understood. In the present study, we found that the beta-lapachone-induced apoptosis of DU145 human prostate carcinoma cells was associated with endoplasmic reticulum (ER) stress, as shown by increased intracellular calcium levels and induction of GRP-78 and GADD-153 proteins, suggesting that the endoplasmic reticulum is a target of beta-lapachone. Beta-Lapachone-induced DU145 cell apoptosis was dose-dependent and accompanied by cleavage of procaspase-12 and phosphorylation of p38, ERK, and JNK, followed by activation of the executioner caspases, caspase-7 and calpain. However, pretreatment with the general caspase inhibitor, z-VAD-FMK, or calpain inhibitors, including ALLM or ALLN, failed to prevent beta-lapachone-induced apoptotic cell death. Blocking the enzyme activity of NQO1 with dicoumarol, a known NQO1 inhibitor, or preventing an increase in intracellular calcium levels using BAPTA-AM, an intracellular calcium chelator, substantially inhibited MAPK phosphorylation, abolished the activation of calpain, caspase-12 and caspase-7, and provided significant protection of beta-lapachone-treated cells. These findings show that beta-lapachone-induced ER stress and MAP kinase phosphorylation is a novel signaling pathway underlying the molecular mechanism of the anticancer effect of beta-lapachone.
authors.affiliation: Institute of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taiwan.
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Lien
authors.forename: Hsiu-Ni
authors.initials: HN
authors.lastname: Kung
authors.forename: Kuo-Shyan
authors.initials: KS
authors.lastname: Lu
authors.forename: Chung-Jiuan
authors.initials: CJ
authors.lastname: Jeng
authors.forename: Yat-Pang
authors.initials: YP
authors.lastname: Chau
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000187:drug effects* / Q000201:enzymology; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006706:Homeostasis; D006801:Humans; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000037:antagonists & inhibitors / Q000378:metabolism; D009285:Naphthoquinones / Q000494:pharmacology*; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects; D013312:Stress, Physiological; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D009285:Naphthoquinones; C014638:beta-lapachone; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D020928:Mitogen-Activated Protein Kinases; D002154:Calpain; D020169:Caspases; D002118:Calcium