title: Hesperidin induces apoptosis and triggers autophagic markers through inhibition of Aurora-A mediated phosphoinositide-3-kinase/Akt/mammalian target of rapamycin and glycogen synthase kinase-3 beta signalling cascades in experimental colon carcinogenesis.
abstract: Abnormalities in the homeostasis mechanisms involved in cell survival and apoptosis are contributing factors for colon carcinogenesis. Interventions of these mechanisms by pharmacologically safer agents gain predominance in colon cancer prevention. We previously reported the chemopreventive efficacy of hesperidin against colon carcinogenesis. In the present study, we aimed at investigating the potential of hesperidin over the abrogated Aurora-A coupled pro-survival phosphoinositide-3-kinase (PI3K)/Akt signalling cascades. Further, the role of hesperidin over apoptosis and mammalian target of rapamycin (mTOR) mediated autophagic responses were studied. Azoxymethane (AOM) induced mouse model of colon carcinogenesis was involved in this study. Hesperidin treatment was provided either in initiation/post-initiation mode respectively. Hesperidin significantly altered AOM mediated anti-apoptotic scenario by modulating Bax/Bcl-2 ratio together with enhanced cytochrome-c release and caspase-3, 9 activations. In addition, hesperidin enhanced p53-p21 axis with concomitant decrease in cell cycle regulator. Hesperidin treatment caused significant up-regulation of tumour suppressor phosphatase and tensin homologue (PTEN) with a reduction in the expression of AOM mediated p-PI3K and p-Akt. Additionally, hesperidin administration exhibited inhibition against p-mTOR expression which in turn led to stimulation of autophagic markers Beclin-1 and LC3-II. Aurora-A an upstream regulator of PI3K/Akt pathway was significantly inhibited by hesperidin. Furthermore, hesperidin administration restored glycogen synthase kinase-3 beta (GSK-3β) activity which in turn prevented the accumulation of oncoproteins β-catenin, c-jun and c-myc. Taken together, hesperidin supplementation initiated apoptosis via targeted inhibition of constitutively activated Aurora-A mediated PI3K/Akt/GSK-3β and mTOR pathways coupled with autophagic stimulation against AOM induced colon carcinogenesis.
authors.affiliation: Department of Biochemistry, Cell Biology Laboratory, University of Madras, Guindy Campus, Chennai 600025, Tamil Nadu, India.
authors.forename: Gowrikumar
authors.initials: G
authors.lastname: Saiprasad
authors.affiliation: Department of Biochemistry, Cell Biology Laboratory, University of Madras, Guindy Campus, Chennai 600025, Tamil Nadu, India.
authors.forename: Palanivel
authors.initials: P
authors.lastname: Chitra
authors.affiliation: Department of Zoology, University of Madras, Guindy Campus, Chennai 600025, Tamil Nadu, India.
authors.forename: Ramar
authors.initials: R
authors.lastname: Manikandan
authors.affiliation: Department of Biochemistry, Cell Biology Laboratory, University of Madras, Guindy Campus, Chennai 600025, Tamil Nadu, India. Electronic address: sudhandiran@yahoo.com.
authors.forename: Ganapasam
authors.initials: G
authors.lastname: Sudhandiran
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D064096:Aurora Kinase A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects; D063646:Carcinogenesis / Q000187:drug effects / Q000378:metabolism; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006569:Hesperidin / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008855:Microscopy, Electron, Scanning; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D064096:Aurora Kinase A; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D006569:Hesperidin; D019869:Phosphatidylinositol 3-Kinases; D058570:TOR Serine-Threonine Kinases; C000605507:Gsk3b protein, mouse
keywords: Apoptosis; Aurora-A; Autophagy; Colon cancer; GSK-3β; PI3K; mTOR