title: N(6)-isopentenyladenosine and analogs activate the NRF2-mediated antioxidant response.
abstract: N(6)-isopentenyladenosine (i(6)A), a naturally occurring modified nucleoside, inhibits the proliferation of human tumor cell lines in vitro, but its mechanism of action remains unclear. Treatment of MCF7 human breast adenocarcinoma cells with i(6)A or with three synthetic analogs (allyl(6)A, benzyl(6)A, and butyl(6)A) inhibited growth and altered gene expression. About 60% of the genes that were differentially expressed in response to i(6)A treatment were also modulated by the analogs, and pathway enrichment analysis identified the NRF2-mediated oxidative stress response as being significantly modulated by all four compounds. Luciferase reporter gene assays in transfected MCF7 cells confirmed that i(6)A activates the transcription factor NRF2. Assays for cellular production of reactive oxygen species indicated that i(6)A and analogs had antioxidant effects, reducing basal levels and inhibiting the H2O2- or 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced production in MCF7 or dHL-60 (HL-60 cells induced to differentiate along the neutrophilic lineage) cell lines, respectively. In vivo, topical application of i(6)A or benzyl(6)A to mouse ears prior to TPA stimulation lessened the inflammatory response and significantly reduced the number of infiltrating neutrophils. These results suggest that i(6)A and analogs trigger a cellular response against oxidative stress and open the possibility of i(6)A and benzyl(6)A being used as topical anti-inflammatory drugs.
authors.affiliation: Department of Predictive and Preventive Medicine, Fondazione IRCCS, Istituto Nazionale dei Tumori, Milan I-20133, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Dassano
authors.affiliation: Laboratory of Radiation Biology and Biomedicine, ENEA, Casaccia Research Centre, Rome I-00123, Italy.
authors.forename: Mariateresa
authors.initials: M
authors.lastname: Mancuso
authors.affiliation: Department of Radiation Physics, Guglielmo Marconi University, Rome I-00193, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Giardullo
authors.affiliation: Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan I-20133, Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: De Cecco
authors.affiliation: Dipartimento di Scienze Biomediche e Cliniche "L. Sacco", Università di Milano, Italy.
authors.forename: Pierangela
authors.initials: P
authors.lastname: Ciuffreda
authors.affiliation: Dipartimento di Scienze della Salute, Università di Milano, Milan I-20142, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Santaniello
authors.affiliation: Laboratory of Radiation Biology and Biomedicine, ENEA, Casaccia Research Centre, Rome I-00123, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Saran
authors.affiliation: Department of Predictive and Preventive Medicine, Fondazione IRCCS, Istituto Nazionale dei Tumori, Milan I-20133, Italy.
authors.forename: Tommaso A
authors.initials: TA
authors.lastname: Dragani
authors.affiliation: Department of Predictive and Preventive Medicine, Fondazione IRCCS, Istituto Nazionale dei Tumori, Milan I-20133, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Colombo
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000494:pharmacology; D004195:Disease Models, Animal; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000009:adverse effects; D007541:Isopentenyladenosine / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000494:pharmacology; D061986:MCF-7 Cells; D051379:Mice; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D010031:Otitis / Q000139:chemically induced / Q000188:drug therapy*; D010084:Oxidation-Reduction / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000009:adverse effects
chemical_list: D000975:Antioxidants; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; C495636:Nfe2l2 protein, mouse; D017382:Reactive Oxygen Species; D007541:Isopentenyladenosine; D006861:Hydrogen Peroxide; D013755:Tetradecanoylphorbol Acetate
keywords: Anti-inflammatory drug; Gene expression; Modified nucleosides; Pathway analysis; Reactive oxygen species; allyl6A, N6-allyladenosine; benzyl6A, N6-benzyladenosine; butyl6A, N6-butyladenosine; i6A, N6-isopentenyladenosine