eIF2 kinases mediate β-lapachone toxicity in yeast and human cancer cells

MAURICIO ARIEL MENACHO; CARLOS RODRÍGUEZ HERNÁNDEZ; MARÍA ANGELES VILLARONGA; JORGE PÉREZ VALLE; JOSÉ GADEA; BORJA BELANDIA; JOSÉ RAMÓN MURGUÍA

CELL CYCLE

LANDES BIOSCIENCE

Lugar: Austin, Texas; Año: 2015

1538-4101

β-lapachone (β-lap) is a novel anticancer agent that selectively induces cell death in human cancer cells, by activation of the NQO1 NAD(P)H dehydrogenase and radical oxygen species (ROS) generation. We characterised the gene expression profile of budding yeast cells treated with β-lap using cDNA microarrays. Genes involved in tolerance to oxidative stress were differentially expressed in β-lap treated cells. β-lap treatment generated reactive oxygen species (ROS), which were efficiently blocked by dicoumarol, an inhibitor of NADH dehydrogenases. A yeast mutant in the mitocondrial NADH dehydrogenase Nde2p was found to be resistant to β-lap treatment, despite it induced ROS production in a WT manner. Most interestingly, DNA damage responses triggered by β-lap were abolished in the nde2∆ mutant. Amino acid biosynthesis genes were also induced in β-lap treated cells, suggesting that β-lap exposure somehow triggered the General Control of Nutrients (GCN) pathway. Accordingly, β-lap treatment increased phosphorylation of eIF2α subunit in a manner dependent on the Gcn2p kinase. eIF2α phosphorylation required Gcn1p, Gcn20p and Nde2p. Gcn2p was also required for cell survival upon exposure to β-lap and to elicit checkpoint responses. Remarkably, β-lap treatment increased phosphorylation of eIF2α in breast tumour cells, in a manner dependent on the Nde2p orthologue AIF, and the eIF2 kinase PERK. These findings uncover a new target pathway of β-lap in yeast and human cells and highlight a previously unknown functional connection between Nde2p, Gcn2p and DNA damage responses.