AKT but not MYC promotes reactive oxygen species-mediated cell death in oxidative culture

ABSTRACT: In addition to driving tumorigenesis, oncogenes can create metabolic vulnerabilities in cancer cells. Here, we tested how the oncogenes AKT and MYC affect the ability to shift between respiration and glycolysis. Using immortalized mammary epithelial cellsMCF10A, we discovered constitutively active AKT but not MYC induced cell death in galactose culture, where cells must rely on oxidative phosphorylation for energy generation. However, the negative effects of AKT were short-lived, and AKT-expressing cells recommenced growth after ~15 days in galactose culture. To identify the mechanisms regulating AKT-mediated cell death, we first used metabolomics and found that AKT cells dying in galactose culture exhibited upregulated glutathione metabolism. Next, using shotgun proteomics, we discovered AKT cells dying in galactose upregulated proteins related to nonsense-mediated mRNA decay (NMD), a known response to oxidative stress. We therefore measured levels of reactive oxygen species (ROS) and discovered galactose culture induced ROS only in cells expressing AKT. Additionally, we found thatdiscovered the ROS scavenger catalase rescued AKT-expressing cells from galactose culture-induced cell death. We then demonstrated that breast cancer cell lines with constitutively active AKT signaling also exhibited cell death in galactose culture and rescue by catalase. Together, our results demonstrate that AKT but not MYC induces a metabolic vulnerability in cancer cells, namely the that restricted flexibility to use oxidative phosphorylation. 

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell

SUBMITTER: DONGQING ZHENG  

LAB HEAD: Nicholas A. Graham

PROVIDER: PXD015122 | Pride | 2020-03-19

REPOSITORIES: Pride