title: The E3 ubiquitin ligase CHIP selectively regulates mutant epidermal growth factor receptor by ubiquitination and degradation.
abstract: Somatic mutation in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) is a decisive factor for the therapeutic response to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in lung adenocarcinoma. The stability of mutant EGFR is maintained by various regulators, including heat shock protein 90 (Hsp90). The C terminus of Hsc70-interacting protein (CHIP) is a Hsp70/Hsp90 co-chaperone and exhibits E3 ubiquitin ligase activity. The high-affinity Hsp90-CHIP complex recognizes and selectively regulates their client proteins. CHIP also works with its own E3 ligase activity independently of Hsp70/Hsp90. Here, we investigated the role of CHIP in regulating EGFR in lung adenocarcinoma and also evaluated the specificity of CHIP's effects on mutant EGFR. In HEK 293T cells transfected with either WT EGFR or EGFR mutants, the overexpression of CHIP selectively decreased the expression of certain EGFR mutants (G719S, L747_E749del A750P and L858R) but not WT EGFR. In a pull-down assay, CHIP selectively interacted with EGFR mutants and simultaneously induced their ubiquitination and proteasomal degradation. The expressions of mutant EGFR in PC9 and H1975 were diminished by CHIP, while the expression of WT EGFR in A549 was nearly not affected. In addition, CHIP overexpression inhibited cell proliferation and xenograft's tumor growth of EGFR mutant cell lines, but not WT EGFR cell lines. EGFR mutant specific ubiquitination by CHIP may provide a crucial regulating mechanism for EGFR in lung adenocarcinoma. Our results suggest that CHIP can be novel therapeutic target for overcoming the EGFR TKI resistance.
authors.affiliation: Cancer Institute of Chungnam National University, Daejeon 35015, South Korea; Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Chaeuk
authors.initials: C
authors.lastname: Chung
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Geon
authors.initials: G
authors.lastname: Yoo
authors.affiliation: National Creative Research Center for Cell Division and Differentiation, Department of Biological Sciences, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 34141, South Korea.
authors.forename: Tackhoon
authors.initials: T
authors.lastname: Kim
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Dahye
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Pathology, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Choong-Sik
authors.initials: CS
authors.lastname: Lee
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Cha
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Yeon Hee
authors.initials: YH
authors.lastname: Park
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Moon
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Sung Soo
authors.initials: SS
authors.lastname: Jung
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Ju Ock
authors.initials: JO
authors.lastname: Kim
authors.affiliation: Department of Oncology, College of Medicine, University of Ulsan Asan Medical Center, Seoul, South Korea.
authors.forename: Jae Cheol
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Cancer Institute of Chungnam National University, Daejeon 35015, South Korea; Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Hee Sun
authors.initials: HS
authors.lastname: Park
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Myoungrin
authors.initials: M
authors.lastname: Park
authors.affiliation: Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
authors.affiliation: National Creative Research Center for Cell Division and Differentiation, Department of Biological Sciences, Korea Advanced Institute of Science and Technology(KAIST), Daejeon 34141, South Korea.
authors.forename: Dae-Sik
authors.initials: DS
authors.lastname: Lim
authors.affiliation: Cancer Institute of Chungnam National University, Daejeon 35015, South Korea; Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea.
authors.forename: Kang Won
authors.initials: KW
authors.lastname: Jang
authors.affiliation: Cancer Institute of Chungnam National University, Daejeon 35015, South Korea; Division of Pulmonology, Department of Internal Medicine, College of Medicine, Chungnam National University, Daejeon 35015, South Korea. Electronic address: naturetoscience2013@gmail.com.
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Lee
mesh_terms: D000072283:A549 Cells; D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009154:Mutation; D011485:Protein Binding; D059748:Proteolysis; D014183:Transplantation, Heterologous; D047368:Tumor Burden / Q000235:genetics; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C467728:STUB1 protein, human; D044767:Ubiquitin-Protein Ligases; D066246:ErbB Receptors
keywords: Adenocarcinoma; CHIP protein; EGFR protein; Ubiquitination