title: 5-demethylnobiletin promotes the formation of polymerized tubulin, leads to G2/M phase arrest and induces autophagy via JNK activation in human lung cancer cells.
abstract: 5-Demethylnobiletin is a hydroxylated polymethoxyflavone found in citrus plants that shows antiproliferative activities in several cancer cell lines. In this study, we investigated the effects and underlying molecular mechanisms of 5-demethylnobiletin on inhibition of cell growth, apoptosis, cell cycle and autophagy in A549 and CL1-5 lung cancer cells. The results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay suggested that 5-demethylnobiletin inhibited cell growth in a dose- and time-dependent manner. Flow cytometry results suggested that 5-demethylnobiletin inhibited proliferation in lung cancer cells by inducing G2/M cell cycle phase arrest but predominantly not through apoptosis. Western blot results illustrated that the blockade of the cell cycle was associated with reduced levels of cdc25 and cdc2. Notably, our results indicated that 5-demethylnobiletin induced significant abnormal microtubule dynamics in A549 and CL1-5 cells, a novel finding. Studies conducted with isolated tubulin and docking models suggest that 5-demethylnobiletin promoted the polymerization of microtubules and bound to the taxol site. Additionally, 5-demethylnobiletin might also induce autophagy via activation of the JNK signaling pathway in A549 and CL1-5 cells. Pretreatment of the cells with the autophagy inhibitor 3-methyladenine significantly potentiated 5-demethylnobiletin-induced apoptosis, suggesting that 5-demethylnobiletin-induced autophagy mitigated cell apoptosis. Further investigation revealed that 5-demethylnobiletin inhibition of CL1-5 lung cancer cell growth was reproducible in a nude mouse model. Taken together, these studies suggest that 5-demethylnobiletin has anti-lung cancer efficacy both in vitro and in vivo possibly through induction of G2/M arrest, autophagy and apoptosis.
authors.affiliation: Department of Food Science, National Pingtung University of Science and Technology, Pingtung, Taiwan.
authors.forename: Yu-Kuo
authors.initials: YK
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan.
authors.forename: Hsin-Chieh
authors.initials: HC
authors.lastname: Wang
authors.affiliation: Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: Chi-Tang
authors.initials: CT
authors.lastname: Ho
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan.
authors.forename: Hisn-Yu
authors.initials: HY
authors.lastname: Chen
authors.affiliation: Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: Shiming
authors.initials: S
authors.lastname: Li
authors.affiliation: Institute of Bioinformatics and Structural Biology and Department of Medical Sciences, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Hong-Lin
authors.initials: HL
authors.lastname: Chan
authors.affiliation: Institute of Bioinformatics and Structural Biology and Department of Medical Sciences, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Ting-Wen
authors.initials: TW
authors.lastname: Chung
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan; Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan.
authors.forename: Kok-Tong
authors.initials: KT
authors.lastname: Tan
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan.
authors.forename: Yi-Ron
authors.initials: YR
authors.lastname: Li
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan; Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan; Department of Medical Research and Education, Taichung Veterans General Hospital, Taichung, Taiwan. Electronic address: lincc@dragon.nchu.edu.tw.
authors.forename: Chi-Chen
authors.initials: CC
authors.lastname: Lin
mesh_terms: D001343:Autophagy / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D004249:DNA Damage; D047309:Flavones / Q000302:isolation & purification / Q000494:pharmacology*; D016195:G2 Phase / Q000187:drug effects*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D058105:Polymerization; D014404:Tubulin / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: C000604601:5-demethylnobiletin; D047309:Flavones; D014404:Tubulin
keywords: 5-Demethylnobiletin; Autophagy; G2/M arrest; JNK; Lung cancer; Tubulin