A large scale proteome analysis of the gefitinib primary resistance overcome by KDAC inhibition in KRAS mutated adenocarcinoma cells overexpressing amphiregulin

Abstract KDAC inhibitors (KDACi) overcome gefitinibprimary resistance in non-small cell lung cancer (NSCLC) including mutant- KRASlung adenocarcinoma. To identify which proteins are involved in the restoration of this sensitivity and to provide new therapeutic targets for mutant- KRASlung adenocarcinoma, we performed an iTRAQ quantitative proteomicanalysis after subcellular fractionation of H358-NSCLC treated with gefitiniband KDACi (TSA/NAM) versus gefitinibalone. The 86 proteins found to have been significantly dysregulated between the two conditions, were mainly involved in cellular metabolism and cell transcription processes. As expected, the pathway related to histone modifications was affected by the KDACi. Pathways known for controlling tumor development and (chemo)-resistance (miRNA biogenesis/ glutathione metabolism) were affected by the KDACi/ gefitinibtreatment. Moreover, 57 dysregulated proteins were upstream of apoptosis (such as eEF1A2and STAT1) and hence provide potential therapeutic targets. The inhibition by siRNA of eEF1A2expression resulted in a slight decrease in H358-NSCLC viability. In addition, eEF1A2and STAT1siRNA transfections suggested that both STAT1and eEF1A2prevent AKT phosphorylation known for enhancing gefitinibresistance in NSCLC. Therefore, altogether our data provide new insights into proteome regulations in the context of overcoming the NSCLC resistance to gefitinibthrough KDACi in H358 KRASmutated and amphiregulin-overexpressing NSCLC cells.