title: A novel mechanism of EML4-ALK rearrangement mediated by chromothripsis in a patient-derived cell line.
abstract: BACKGROUND
  EML4-ALK is a driver oncogene in non-small-cell lung cancer (NSCLC) and has been developed into a promising molecular target for antitumor agents. Although EML4-ALK is reported to be formed by inversion of chromosome 2, other mechanisms of this gene fusion remain unknown. This study aimed to examine the mechanism of EML4-ALK rearrangement using a novel cell line with the EML4-ALK fusion gene.
  
  
  METHODS
  An EML4-ALK-positive cell line, termed JFCR-LC649, was established from pleomorphic carcinoma, a rare subtype of NSCLC. We investigated the chromosomal aberrations using fluorescence in situ hybridization and comparative genomic hybridization (CGH). Alectinib/CH5424802, a selective ALK inhibitor, was evaluated in the antitumor activity against JFCR-LC649 in vitro and in vivo xenograft model.
  
  
  RESULTS
  We established an EML4-ALK-positive cell line, termed JFCR-LC649, derived from a patient with NSCLC and revealed that the JFCR-LC649 cells harbor variant 3 of the EML4-ALK fusion with twofold copy number gain. Interestingly, comparative genomic hybridization and metaphase-fluorescence in situ hybridization analysis showed that in addition to two normal chromosome 2, JFCR-LC649 cells contained two aberrant chromosome 2 that were fragmented and scattered. These observations provided the first evidence that EML4-ALK fusion in JFCR-LC649 cells was formed in chromosome 2 by a distinct mechanism of genomic rearrangement, termed chromothripsis. Furthermore, a selective ALK inhibitor alectinib/CH5424802 suppressed tumor growth of the JFCR-LC649 cells through inhibition of phospho-ALK in vitro and in vivo in a xenograft model.
  
  
  CONCLUSIONS
  Our results suggested that chromothripsis may be a mechanism of oncogenic rearrangement of EML4-ALK. In addition, alectinib was effective against EML4-ALK-positive tumors with ALK copy number gain mediated by chromothripsis.
authors.affiliation: *Research Division, Chugai Pharmaceutical Co., Ltd., Kamakura, Japan; †Division of Pathology, The Cancer Institute; ‡Division of Clinical Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research; and §Department of Pathology, The Cancer Institute Hospital, Tokyo, Japan.
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Kodama
authors.forename: Noriko
authors.initials: N
authors.lastname: Motoi
authors.forename: Hironori
authors.initials: H
authors.lastname: Ninomiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Kunio
authors.initials: K
authors.lastname: Kitada
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Tsukaguchi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Satoh
authors.forename: Kimie
authors.initials: K
authors.lastname: Nomura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nagano
authors.forename: Nobuya
authors.initials: N
authors.lastname: Ishii
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Terui
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Hatake
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishikawa
mesh_terms: D000818:Animals; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D019457:Chromosome Breakage; D005260:Female; D050939:Gene Fusion; D015321:Gene Rearrangement; D064593:Heterografts; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D048629:Micronuclei, Chromosome-Defective; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
chemical_list: C522504:EML4-ALK fusion protein, human; D015514:Oncogene Proteins, Fusion