title: FK228 and oncogenic H-Ras synergistically induce Mek1/2 and Nox-1 to generate reactive oxygen species for differential cell death.
abstract: To investigate the mechanism behind the pro-apoptotic ability of oncogenic H-Ras to enhance FK228-induced apoptosis, we primarily used the 10T1/2-TR-H-Ras cell line, in which ectopic expression of oncogenic H-Ras(V12) is controlled by the addition of tetracycline into cultures, and secondarily used oncogenic H-Ras-expressing MCF10A cells in our studies. Our results showed the pro-apoptotic roles of Mek1/2 activation, nicotinamide adenine dinucleotide phosphate-oxidase 1 (Nox-1) elevation, and reactive oxygen species (ROS) production in FK228-induced selective cell death of oncogenic H-Ras-expressing cells versus counterpart cells. We found that although Nox-1 elevation and ROS production played essential roles in oncogenic H-Ras-induced cell proliferation and morphological transformation, the expression of oncogenic H-Ras and FK228 treatment synergistically induced activation of Mek1/2. This activation resulted in differentially increased Nox-1 elevation and ROS production leading to selective cell death of oncogenic H-Ras-expressing cells versus counterpart cells. We also found that FK228 treatment induced mitochondrial ROS and Mek1/2 activation, bypassing Raf-1, to downstream Erk1/2, participating in the induction of selective cell death. Thus, the pro-apoptotic abilities of Mek1/2 and Nox-1 should be considered as potential targets in designing therapeutic protocols using FK228 to assure ROS-mediated cell death for treating cancer cells acquiring Ras activation.
authors.affiliation: Department of Comparative Medicine, The University of Tennessee, Knoxville, USA.
authors.forename: Shambhunath
authors.initials: S
authors.lastname: Choudhary
authors.forename: Kusum
authors.initials: K
authors.lastname: Rathore
authors.forename: Hwa-Chain Robert
authors.initials: HC
authors.lastname: Wang
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation; D002478:Cells, Cultured; D047630:Depsipeptides / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000378:metabolism; D051379:Mice; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D000074624:NADPH Oxidase 1; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000903:Antibiotics, Antineoplastic; D047630:Depsipeptides; D017382:Reactive Oxygen Species; C087123:romidepsin; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D016283:Proto-Oncogene Proteins p21(ras); D013752:Tetracycline