title: Stability of the cancer target DDIAS is regulated by the CHIP/HSP70 pathway in lung cancer cells.
abstract: DNA damage-induced apoptosis suppressor (DDIAS) rescues lung cancer cells from apoptosis in response to DNA damage. DDIAS is transcriptionally activated by NFATc1 and EGF-mediated ERK5/MEF2B, leading to cisplatin resistance and cell invasion. Therefore, DDIAS is suggested as a therapeutic target for lung cancer. Here, we report that DDIAS stability is regulated by E3 U-box ubiquitin ligase carboxyl terminus of HSP70-interacting protein (CHIP)-mediated proteasomal degradation. We first isolated CHIP as an interacting partner of DDIAS by yeast two-hybrid screening. CHIP physically associated with both the N- and C-terminal regions of DDIAS, targeting it for proteasomal degradation and reducing the DDIAS half-life. CHIP overexpression analyses indicated that the tetratrico peptide repeat (TPR) domain and the U-box are required for DDIAS ubiquitination. It is likely that HSP70-bound DDIAS is recruited to the CHIP E3 ligase via the TPR domain, suggesting DDIAS as a client protein of HSP70. In addition, CHIP overexpression in lung cancer cells expressing high DDIAS levels induced significant growth inhibition by enhancing DDIAS degradation. Furthermore, simultaneous CHIP overexpression and DNA damage agent treatment caused a substantial increase in the apoptosis of lung cancer cells. Taken together, these findings indicate that the stability of the DDIAS protein is regulated by CHIP/HSP70-mediated proteasomal degradation and that CHIP overexpression stimulates the apoptosis of lung cancer cells in response to DNA-damaging agents.
authors.affiliation: Personalized Genomic Medicine Research Center, KRIBB, Daejeon 305-806, Korea.|Functional Genomics, University of Science and Technology, Daejeon 305-701, Korea.
authors.forename: Kyoung-Jae
authors.initials: KJ
authors.lastname: Won
authors.affiliation: Personalized Genomic Medicine Research Center, KRIBB, Daejeon 305-806, Korea.
authors.forename: Joo-Young
authors.initials: JY
authors.lastname: Im
authors.affiliation: Personalized Genomic Medicine Research Center, KRIBB, Daejeon 305-806, Korea.
authors.forename: Bo-Kyung
authors.initials: BK
authors.lastname: Kim
authors.affiliation: Metabolic Regulation Research Center, KRIBB, Daejeon 305-806, Korea.
authors.forename: Hyun Seung
authors.initials: HS
authors.lastname: Ban
authors.affiliation: Personalized Genomic Medicine Research Center, KRIBB, Daejeon 305-806, Korea.
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Jung
authors.affiliation: Oligo Team, ST Pharm. Co., LTD, Sihwa Industrial Complex 1, Kyunggido 429-848, Korea.
authors.forename: Kyeong Eun
authors.initials: KE
authors.lastname: Jung
authors.affiliation: Personalized Genomic Medicine Research Center, KRIBB, Daejeon 305-806, Korea.|Functional Genomics, University of Science and Technology, Daejeon 305-701, Korea.
authors.forename: Misun
authors.initials: M
authors.lastname: Won
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D051017:Apoptosis Regulatory Proteins / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000627:therapeutic use; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D054875:Ubiquitination / Q000235:genetics
chemical_list: D051017:Apoptosis Regulatory Proteins; D018797:Cell Cycle Proteins; C000621244:DDIAS protein, human; D009363:Neoplasm Proteins; C467728:STUB1 protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex; D002945:Cisplatin