title: Nrf2 but not autophagy inhibition is associated with the survival of wild-type epidermal growth factor receptor non-small cell lung cancer cells.
abstract: Non-small cell lung cancer (NSCLC) is one of the most common malignancies in the world. Icotinib and Gefitinib are two epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) that have been used to treat NSCLC. While it is well known that mutations of EGFR can affect the sensitivity of NSCLC to the EGFR-TKI, other mechanisms may also be adopted by lung cancer cells to develop resistance to EGFR-TKI treatment. Cancer cells can use multiple adaptive mechanisms such as activation of autophagy and Nrf2 to protect against various stresses and chemotherapeutic drugs. Whether autophagy or Nrf2 activation contributes to the resistance of NSCLC to EGFR-TKI treatment in wild-type EGFR NSCLC cells remains elusive. In the present study, we confirmed that Icotinib and Gefitinib induced apoptosis in EGFR mutant HCC827 but not in EGFR wild-type A549 NSCLC cells. Icotinib and Gefitinib did not induce autophagic flux or inhibit mTOR in A549 cells. Moreover, suppression of autophagy by chloroquine, a lysosomal inhibitor, did not affect Icotinib- or Gefitinib-induced cell death in A549 cells. In contrast, Brusatol, an Nrf2 inhibitor, significantly suppressed the cell survival of A549 cells. However, Brusatol did not further sensitize A549 cells to EGFR TKI-induced cell death. Results from this study suggest that inhibition of Nrf2 can decrease cell vitality of EGFR wild-type A549 cells independent of autophagy.
authors.affiliation: Department of Pulmonary, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China; Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Hong-Min
authors.initials: HM
authors.lastname: Ni
authors.affiliation: Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Wen-Xing
authors.initials: WX
authors.lastname: Ding
authors.affiliation: Department of Pulmonary, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address: eddiedong8@hotmail.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhong
mesh_terms: D001343:Autophagy / Q000502:physiology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*
chemical_list: D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D066246:ErbB Receptors
keywords: Apoptosis; Autophagy; EGFR; Lung cancer; Nrf2