NOX4 mediates cytoprotective autophagy induced by the EGFR inhibitor erlotinib in head and neck cancer cells.

Published

Journal Article

Most head and neck squamous cell carcinomas (HNSCCs) overexpress epidermal growth factor receptor (EGFR) and EGFR inhibitors are routinely used in the treatment of HNSCC. However, many HNSCC tumors do not respond or become refractory to EGFR inhibitors. Autophagy, which is a stress-induced cellular self-degradation process, has been reported to reduce the efficacy of chemotherapy in various disease models. The purpose of this study is to determine if the efficacy of the EGFR inhibitor erlotinib is reduced by activation of autophagy via NOX4-mediated oxidative stress in HNSCC cells. Erlotinib induced the expression of the autophagy marker LC3B-II and autophagosome formation in FaDu and Cal-27 cells. Inhibition of autophagy by chloroquine and knockdown of autophagy pathway genes Beclin-1 and Atg5 sensitized both cell lines to erlotinib-induced cytotoxicity, suggesting that autophagy may serve as a protective mechanism. Treatment with catalase (CAT) and diphenylene iodonium (DPI) in the presence of erlotinib suppressed the increase in LC3B-II expression in FaDu and Cal-27 cells. Erlotinib increased NOX4 mRNA and protein expression by increasing its promoter activity and mRNA stability in FaDu cells. Knockdown of NOX4 using adenoviral siNOX4 partially suppressed erlotinib-induced LC3B-II expression, while overexpression of NOX4 increased expression of LC3B-II. These studies suggest that erlotinib may activate autophagy in HNSCC cells as a pro-survival mechanism, and NOX4 may play a role in mediating this effect.

Full Text

Duke Authors

Cited Authors

  • Sobhakumari, A; Schickling, BM; Love-Homan, L; Raeburn, A; Fletcher, EVM; Case, AJ; Domann, FE; Miller, FJ; Simons, AL

Published Date

  • November 2013

Published In

Volume / Issue

  • 272 / 3

Start / End Page

  • 736 - 745

PubMed ID

  • 23917044

Pubmed Central ID

  • 23917044

Electronic International Standard Serial Number (EISSN)

  • 1096-0333

International Standard Serial Number (ISSN)

  • 0041-008X

Digital Object Identifier (DOI)

  • 10.1016/j.taap.2013.07.013

Language

  • eng