title: Guaraná a Caffeine-Rich Food Increases Oxaliplatin Sensitivity of Colorectal HT-29 Cells by Apoptosis Pathway Modulation.
abstract: We investigated the in vitro effects of guaraná and its main metabolites (caffeine, theobromine and catechin) on cytotoxicity and cell proliferation on colorectal cancer (CRC) line HT-29 cells and on oxaliplatin sensitivity. The cells were exposed to different concentrations of guaraná extract with and without oxaliplatin. The concentrations of bioactive molecules were also estimated considering their potential proportion on guaraná hydro-alcoholic extract. Apoptosis effect was analyzed by annexin V quantification using flow cytometry, while apoptosis pathway gene modulation (p53, Bax/Bcl-2 genes ratio, caspases 8 and 3) was determined by qRT-PCR analysis. Cells exposed to guaraná at a concentration of 100 μg/mL presented a similar cytotoxic effect as HT-29 cells treated with oxaliplatin and did not affect the sensitivity of the drug. Guaraná presented cell anti-proliferative effect and increased anti-proliferative oxaliplatin sensitivity at all concentrations tested here. Guaraná was able to induce apoptosis and up-regulate the p53 and Bax/Bcl-2 genes.
authors.forename: Francine Carla
authors.initials: FC
authors.lastname: Cadoná
authors.forename: Alencar Kolinski
authors.initials: AK
authors.lastname: Machado
authors.forename: Verônica Farina
authors.initials: VF
authors.lastname: Azzolin
authors.forename: Fernanda
authors.initials: F
authors.lastname: Barbisan
authors.forename: Eduardo Bortoluzzi
authors.initials: EB
authors.lastname: Dornelles
authors.forename: Werner
authors.initials: W
authors.lastname: Glanzner
authors.forename: Paulo Bayard Dias
authors.initials: PBD
authors.lastname: Gonçalves
authors.forename: Charles Elias
authors.initials: CE
authors.lastname: Assmann
authors.forename: Euler Esteves
authors.initials: EE
authors.lastname: Ribeiro
authors.affiliation: I.B.M. da Cruz, Av Roraima 1000, Building 19, Santa Maria-RS, Brazil.
authors.forename: Ivana Beatrice Mânica da
authors.initials: IBMD
authors.lastname: Cruz
keywords: Guaraná; HT-29; cancer colorectal; oxaliplatin