title: Underlying mechanism of quercetin-induced cell death in human glioma cells.
abstract: There has been considerable interest in recent years in the anti-tumor activities of flavonoids. Quercetin, a ubiquitous bioactive flavonoid, can inhibit proliferation and induce apoptosis in a variety of cancer cells. However, the precise molecular mechanism by which quercetin induces apoptosis in cancer cells is poorly understood. The present study was undertaken to examine the effect of quercetin on cell viability and to determine its underlying mechanism in human glioma cells. Quercetin resulted in loss of cell viability in a dose- and time-dependent manner and the decrease in cell viability was mainly attributed to cell death. Quercetin did not increase reactive oxygen species (ROS) generation and the quercetin-induced cell death was also not affected by antioxidants, suggesting that ROS generation is not involved in loss of cell viability. Western blot analysis showed that quercetin treatment caused rapid reduction in phosphorylation of extracellular signal-regulated kinase (ERK) and Akt. Transient transfection with constitutively active forms of MEK and Akt protected against the quercetin-induced loss of cell viability. Quercetin-induced depolarization of mitochondrial membrane potential. Caspase activity was stimulated by quercetin and caspase inhibitors prevented the quercetin-induced loss of cell viability. Quercetin resulted in a decrease in expression of survivin, antiapoptotic proteins. Taken together, these findings suggest that quercetin results in human glioma cell death through caspase-dependent mechanisms involving down-regulation of ERK, Akt, and survivin.
authors.affiliation: Department of Neurosurgery, College of Medicine, Pusan National University, Pusan 602-739, South Korea.
authors.forename: Eui Joong
authors.initials: EJ
authors.lastname: Kim
authors.forename: Chang Hwa
authors.initials: CH
authors.lastname: Choi
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Park
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Kang
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Kim
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism* / Q000494:pharmacology* / Q000627:therapeutic use; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011794:Quercetin / Q000378:metabolism* / Q000494:pharmacology* / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism; D000077022:Survivin; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism
chemical_list: D000975:Antioxidants; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D017382:Reactive Oxygen Species; D000077022:Survivin; D051636:X-Linked Inhibitor of Apoptosis Protein; D011794:Quercetin; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020169:Caspases