title: Establishment of cisplatin-resistant ovarian yolk sac tumor cells and investigation of the mechanism of cisplatin resistance using this cell line.
abstract: BACKGROUND
  Cisplatin is used as a key drug for ovarian yolk sac tumor (YST), but relapse may occur. Details of the molecular mechanism responsible for cisplatin resistance remain unclear.
  
  
  METHODS
  We established cisplatin-resistant ovarian YST cells (NOY1-CR) from parent NOY1. To characterize these cells, we examined cross-resistance to other anticancer drugs. Then, cDNA microarray analysis was performed to quantify gene expression in NOY1 and NOY1-CR cells. The expression of several potential genes related to drug resistance was compared with parent cells by real-time PCR and Western blotting. Knockdown experiments using small interfering RNA (siRNA) were also performed to confirm the genetic association with drug resistance.
  
  
  RESULTS
  The IC(50) for cisplatin of NOY1-CR was 22.3-fold higher than that for parent cells. NOY1-CR cells showed cross-resistance to some drugs, but not to VP-16 and bleomycin. Microarray analysis identified 315 up-regulated and 412 down-regulated genes in NOY1-CR cells. Knockdown of GSTA1, which was up-regulated in resistant cells, by GSTA1 siRNA restored cisplatin sensitivity in NOY1-CR cells.
  
  
  CONCLUSIONS
  Our data suggest the molecular mechanisms of cisplatin resistance and show the potential for GSTA1 to become a novel therapeutic target for cisplatin-resistant ovarian YST.
authors.affiliation: Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan. shiba@med.nagoya-u.ac.jp
authors.forename: Kiyosumi
authors.initials: K
authors.lastname: Shibata
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Umezu
authors.forename: Maiko
authors.initials: M
authors.lastname: Sakurai
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kajiyama
authors.forename: Eiko
authors.initials: E
authors.lastname: Yamamoto
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ino
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nawa
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Kikkawa
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D018240:Endodermal Sinus Tumor / Q000188:drug therapy* / Q000235:genetics; D005260:Female; D020868:Gene Silencing; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000235:genetics; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D034741:RNA, Small Interfering; C484555:GSTA1 protein, human; D005982:Glutathione Transferase; D002945:Cisplatin