Expert Opin Ther Targets. 2018 Dec 17.
INTRODUCTION: Kelch-like ECH associated protein 1/Nuclear factor erythroid 2-like factor 2 (Keap1-Nrf2) signaling plays a pivotal role in response to oxidative stress in lung cancer. Mutations in KEAP1/NFE2L2 genes always cause persistent Nrf2 activation in lung cancer cells that confers therapeutic resistance and aggressive tumorigenic activity, dictating either poor prognosis or short duration of response to chemotherapy in clinical observations. These findings suggest that modulation of Keap1-Nrf2 signaling presents to be a promising therapeutic target in adenocarcinomas of lung. Areas covered: We provide a review on the mechanisms underlying the regulation of Keap1-Nrf2 at different stages, including genetic mutations, epigenetic modifications, translational/post-translational alterations, and protein-protein interactions. Based on the current knowledge, we discuss the possibilities of intervening Keap1-Nrf2 in lung adenocarcinoma as a therapeutic target. Expert opinion: It is prevalently conceived that Keap1-Nrf2 signaling plays different roles at diverse stages of cancer: on one hand, Nrf2-deficiency are susceptible to carcinogens; on the other hand, Nrf2 activation has been proven to promote tumor growth. Although various Nrf2 or Keap1 inhibitors have been reported during the last decades, none of these inhibitors are currently under clinical studies or in clinical applications, suggesting that sole inhibition of Nrf2 might not be sufficient to suppress tumor growth. On the basis of current studies, we suggest that rational combination of Nrf2 suppression with chemical agents which cause enhanced oxidative imbalance or abnormal metabolism would be promising in the treatment of lung adenocarcinoma. This review provides an opportunity to consider Nrf2 as the 'Achilles heel' of lung adenocarcinoma with Nrf2 activation.
Keywords: Keap1; Nrf2; adenocarcinoma; lung; targets