PMID- 25477514 OWN - NLM STAT- MEDLINE DCOM- 20150421 LR - 20210205 IS - 1083-351X (Electronic) IS - 0021-9258 (Print) IS - 0021-9258 (Linking) VI - 290 IP - 4 DP - 2015 Jan 23 TI - Constitutive activation of epidermal growth factor receptor promotes tumorigenesis of Cr(VI)-transformed cells through decreased reactive oxygen species and apoptosis resistance development. PG - 2213-24 LID - 10.1074/jbc.M114.619783 [doi] AB - Hexavalent chromium (Cr(VI)) compounds are well-established lung carcinogens. Epidermal growth factor receptor (EGFR) is a tyrosine kinase transmembrane receptor that regulates cell survival, tumor invasion, and angiogenesis. Our results show that chronic exposure of human bronchial epithelial (BEAS-2B) cells to Cr(VI) is able to cause malignant cell transformation. These transformed cells exhibit apoptosis resistance with reduced poly ADP-ribose polymerase cleavage (C-PARP) and Bax expression and enhanced expressions of Bcl-2 and Bcl-xL. These transformed cells also exhibit reduced capacity of reactive oxygen species (ROS) generation along with elevated expression of antioxidant manganese superoxide dismutase 2 (SOD2). The expression of this antioxidant was also elevated in lung tumor tissue from a worker exposed to Cr(VI) for 19 years. EGFR was activated in Cr(VI)-transformed BEAS-2B cells, lung tissue from animals exposed to Cr(VI) particles, and human lung tumor tissue. Further study indicates that constitutive activation of EGFR in Cr(VI)-transformed cells was due to increased binding to its ligand amphiregulin (AREG). Inhibition of EGFR or AREG increased Bax expression and reduced Bcl-2 expression, resulting in reduced apoptosis resistance. Furthermore, inhibition of AREG or EGFR restored capacity of ROS generation and decreased SOD2 expression. PI3K/AKT was activated, which depended on EGFR in Cr(VI)-transformed BEAS-2B cells. Inhibition of PI3K/AKT increased ROS generation and reduced SOD2 expression, resulting in reduced apoptosis resistance with commitment increase in Bax expression and reduction of Bcl-2 expression. Xenograft mouse tumor study further demonstrates the essential role of EGFR in tumorigenesis of Cr(VI)-transformed cells. In summary, the present study suggests that ligand-dependent constitutive activation of EGFR causes reduced ROS generation and increased antioxidant expression, leading to development of apoptosis resistance, contributing to Cr(VI)-induced tumorigenesis. CI - (c) 2015 by The American Society for Biochemistry and Molecular Biology, Inc. FAU - Kim, Donghern AU - Kim D AD - From the Graduate Center for Toxicology and. FAU - Dai, Jin AU - Dai J AD - From the Graduate Center for Toxicology and. FAU - Fai, Leonard Yenwong AU - Fai LY AD - From the Graduate Center for Toxicology and. FAU - Yao, Hua AU - Yao H AD - Department of Stomatology, First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang 310003, China, and. FAU - Son, Young-Ok AU - Son YO AD - Center for Research on Environmental Disease, University of Kentucky, Lexington, Kentucky 40536. FAU - Wang, Lei AU - Wang L AD - Center for Research on Environmental Disease, University of Kentucky, Lexington, Kentucky 40536. FAU - Pratheeshkumar, Poyil AU - Pratheeshkumar P AD - Center for Research on Environmental Disease, University of Kentucky, Lexington, Kentucky 40536. FAU - Kondo, Kazuya AU - Kondo K AD - Department of Oncological Medical Services, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8509, Japan. FAU - Shi, Xianglin AU - Shi X AD - Center for Research on Environmental Disease, University of Kentucky, Lexington, Kentucky 40536. FAU - Zhang, Zhuo AU - Zhang Z AD - From the Graduate Center for Toxicology and zhuo.zhang@uky.edu. LA - eng GR - R01 ES018883/ES/NIEHS NIH HHS/United States GR - R03CA171604/CA/NCI NIH HHS/United States GR - R01 ES021771/ES/NIEHS NIH HHS/United States GR - P30 CA177558/CA/NCI NIH HHS/United States GR - R01ES018883/ES/NIEHS NIH HHS/United States GR - R03 CA171604/CA/NCI NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural DEP - 20141204 PL - United States TA - J Biol Chem JT - The Journal of biological chemistry JID - 2985121R RN - 0 (Amphiregulin) RN - 0 (Antioxidants) RN - 0 (BAX protein, human) RN - 0 (Ligands) RN - 0 (Proto-Oncogene Proteins c-bcl-2) RN - 0 (Reactive Oxygen Species) RN - 0 (bcl-2-Associated X Protein) RN - 0R0008Q3JB (Chromium) RN - 18540-29-9 (chromium hexavalent ion) RN - 7OV03QG267 (Nickel) RN - EC 2.7.10.1 (EGFR protein, human) RN - EC 2.7.10.1 (EGFR protein, mouse) RN - EC 2.7.10.1 (ErbB Receptors) RN - N712M78A8G (Arsenic) SB - IM MH - Amphiregulin/chemistry MH - Animals MH - Antioxidants/chemistry MH - *Apoptosis MH - Arsenic/chemistry MH - Base Sequence MH - Cell Line, Tumor MH - Chromium/*chemistry MH - ErbB Receptors/*metabolism MH - Female MH - *Gene Expression Regulation, Neoplastic MH - Gene Silencing MH - Humans MH - Ligands MH - Mice MH - Mice, Inbred BALB C MH - Mice, Nude MH - Microscopy, Fluorescence MH - Molecular Sequence Data MH - Neoplasm Transplantation MH - Nickel/chemistry MH - Proto-Oncogene Proteins c-bcl-2/metabolism MH - Reactive Oxygen Species/*metabolism MH - Sequence Homology, Nucleic Acid MH - bcl-2-Associated X Protein/metabolism PMC - PMC4303672 OTO - NOTNLM OT - Antioxidant OT - Apoptosis OT - Carcinogenesis OT - Cr(VI) OT - Epidermal Growth Factor Receptor (EGFR) OT - Reactive Oxygen Species (ROS) EDAT- 2014/12/06 06:00 MHDA- 2015/04/22 06:00 PMCR- 2016/01/23 CRDT- 2014/12/06 06:00 PHST- 2014/12/06 06:00 [entrez] PHST- 2014/12/06 06:00 [pubmed] PHST- 2015/04/22 06:00 [medline] PHST- 2016/01/23 00:00 [pmc-release] AID - S0021-9258(20)57758-2 [pii] AID - M114.619783 [pii] AID - 10.1074/jbc.M114.619783 [doi] PST - ppublish SO - J Biol Chem. 2015 Jan 23;290(4):2213-24. doi: 10.1074/jbc.M114.619783. Epub 2014 Dec 4.