title: Establishment of a novel clear cell sarcoma cell line (Hewga-CCS), and investigation of the antitumor effects of pazopanib on Hewga-CCS.
abstract: BACKGROUND
  Clear cell sarcoma (CCS) is a therapeutically unresolved, aggressive, soft tissue sarcoma (STS) that predominantly affects young adults. This sarcoma is defined by t(12;22)(q13;q12) translocation, which leads to the fusion of Ewing sarcoma gene (EWS) to activating transcription factor 1 (ATF1) gene, producing a chimeric EWS-ATF1 fusion gene. We established a novel CCS cell line called Hewga-CCS and developed an orthotopic tumor xenograft model to enable comprehensive bench-side investigation for intensive basic and preclinical research in CCS with a paucity of experimental cell lines.
  
  
  METHODS
  Hewga-CCS was derived from skin metastatic lesions of a CCS developed in a 34-year-old female. The karyotype and chimeric transcript were analyzed. Xenografts were established and characterized by morphology and immunohistochemical reactivity. Subsequently, the antitumor effects of pazopanib, a recently approved, novel, multitargeted, tyrosine kinase inhibitor (TKI) used for the treatment of advanced soft tissue sarcoma, on Hewga-CCS were assessed in vitro and in vivo.
  
  
  RESULTS
  Hewga-CCS harbored the type 2 EWS-ATF1 transcript. Xenografts morphologically mimicked the primary tumor and expressed S-100 protein and antigens associated with melanin synthesis (Melan-A, HMB45). Pazopanib suppressed the growth of Hewga-CCS both in vivo and in vitro. A phospho-receptor tyrosine kinase array revealed phosphorylation of c-MET, but not of VEGFR, in Hewga-CCS. Subsequent experiments showed that pazopanib exerted antitumor effects through the inhibition of HGF/c-MET signaling.
  
  
  CONCLUSIONS
  CCS is a rare, devastating disease, and our established CCS cell line and xenograft model may be a useful tool for further in-depth investigation and understanding of the drug-sensitivity mechanism.
authors.forename: Hidetatsu
authors.initials: H
authors.lastname: Outani
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Toru
authors.initials: T
authors.lastname: Wakamatsu
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Imura
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Hamada
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Araki
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Itoh
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. nnaka@ort.med.osaka-u.ac.jp.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Naka
mesh_terms: D000328:Adult; D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D056905:Chromosome Breakpoints; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007191:Indazoles; D051379:Mice; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology*; D018227:Sarcoma, Clear Cell / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects; D012983:Soft Tissue Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D013449:Sulfonamides / Q000494:pharmacology*; D014157:Transcription Factors / Q000235:genetics; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; C111598:EWS-ATF1 fusion protein, human; D007191:Indazoles; D015514:Oncogene Proteins, Fusion; D011743:Pyrimidines; D013449:Sulfonamides; D014157:Transcription Factors; C516667:pazopanib; D019859:Proto-Oncogene Proteins c-met