title: ROS mediates interferon gamma induced phosphorylation of Src, through the Raf/ERK pathway, in MCF-7 human breast cancer cell line.
abstract: Interferon gamma (IFN-ɣ) is a pleiotropic cytokine which plays dual contrasting roles in cancer. Although IFN-ɣ has been clinically used to treat various malignancies, it was recently shown to have protumorigenic activities. Reactive oxygen species (ROS) are overproduced in cancer cells, mainly due to NADPH oxidase activity, which results into several changes in signaling pathways. In this study, we examined IFN-ɣ effect on the phosphorylation levels of key signaling proteins, through ROS production, in the human breast cancer cell line MCF-7. After treatment by IFN-ɣ, results showed a significant increase in the phosphorylation of STAT1, Src, raf, AKT, ERK1/2 and p38 signaling molecules, in a time specific manner. Src and Raf were found to be involved in early stages of IFN-ɣ signaling since their phosphorylation increased very rapidly. Selective inhibition of Src-family kinases resulted in an immediate significant decrease in the phosphorylation status of Raf and ERK1/2, but not p38 and AKT. On the other hand, IFN-ɣ resulted in ROS generation, through H2O2production, whereas pre-treatment with the ROS inhibitor NAC caused ROS inhibition and a significant decrease in the phosphorylation levels of AKT, ERK1/2, p38 and STAT1. Moreover, pretreatment with a selective NOX1 inhibitor resulted in a significant decrease of AKT phosphorylation. Finally, no direct relationship was found between ROS production and calcium mobilization. In summary, IFN-ɣ signaling in MCF-7 cell line is ROS-dependent and follows the Src/Raf/ERK pathway whereas its signaling through the AKT pathway is highly dependent on NOX1.
authors.affiliation: ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon.|Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon.
authors.forename: Kazem
authors.identifier: http://orcid.org/0000-0002-9887-072X
authors.initials: K
authors.lastname: Zibara
authors.affiliation: Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
authors.forename: Asad
authors.initials: A
authors.lastname: Zeidan
authors.affiliation: ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon.
authors.forename: Hassan
authors.initials: H
authors.lastname: Bjeije
authors.affiliation: ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon.
authors.forename: Nouhad
authors.initials: N
authors.lastname: Kassem
authors.affiliation: Biochemistry Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon.
authors.forename: Bassam
authors.initials: B
authors.lastname: Badran
authors.affiliation: ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon. nabilzein@hotmail.fr.|Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon. nabilzein@hotmail.fr.
authors.forename: Nabil
authors.initials: N
authors.lastname: El-Zein
keywords: AKT; Cancer; ERK1/2; IFN-ɣ; MCF-7; NOX; ROS; Raf; STAT1; Signal transduction; Src; p38