title: Identification of genes associated with cisplatin resistance in human oral squamous cell carcinoma cell line.
abstract: BACKGROUND
  Cisplatin is widely used for chemotherapy of head and neck squamous cell carcinoma. However, details of the molecular mechanism responsible for cisplatin resistance are still unclear. The aim of this study was to identify the expression of genes related to cisplatin resistance in oral squamous cell carcinoma cells.
  
  
  METHODS
  A cisplatin-resistant cell line, Tca/cisplatin, was established from a cisplatin-sensitive cell line, Tca8113, which was derived from moderately-differentiated tongue squamous cell carcinoma. Global gene expression in this resistant cell line and its sensitive parent cell line was analyzed using Affymetrix HG-U95Av2 microarrays. Candidate genes involved in DNA repair, the MAP pathway and cell cycle regulation were chosen to validate the microarray analysis results. Cell cycle distribution and apoptosis following cisplatin exposure were also investigated.
  
  
  RESULTS
  Cisplatin resistance in Tca/cisplatin cells was stable for two years in cisplatin-free culture medium. The IC50 for cisplatin in Tca/cisplatin was 6.5-fold higher than that in Tca8113. Microarray analysis identified 38 genes that were up-regulated and 25 that were down-regulated in this cell line. Some were novel candidates, while others are involved in well-characterized mechanisms that could be relevant to cisplatin resistance, such as RECQL for DNA repair and MAP2K6 in the MAP pathway; all the genes were further validated by Real-time PCR. The cell cycle-regulated genes CCND1 and CCND3 were involved in cisplatin resistance; 24-hour exposure to 10 microM cisplatin induced a marked S phase block in Tca/cisplatin cells but not in Tca8113 cells.
  
  
  CONCLUSIONS
  The Tca8113 cell line and its stable drug-resistant variant Tca/cisplatin provided a useful model for identifying candidate genes responsible for the mechanism of cisplatin resistance in oral squamous cell carcinoma. Our data provide a useful basis for screening candidate targets for early diagnosis and further intervention in cisplatin resistance.
authors.affiliation: Department of Oral & Maxillofacial Surgery, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200011, China. pingzhang73@hotmail.com
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Zhou
authors.forename: Weiliu
authors.initials: W
authors.lastname: Qiu
authors.forename: Fangan
authors.initials: F
authors.lastname: Chen
authors.forename: Wantao
authors.initials: W
authors.lastname: Chen
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D019938:Cyclin D1 / Q000235:genetics; D056743:Cyclin D3; D016213:Cyclins / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009062:Mouth Neoplasms / Q000235:genetics* / Q000473:pathology; D010641:Phenotype; D013997:Time Factors
chemical_list: C534696:CCND3 protein, human; D056743:Cyclin D3; D016213:Cyclins; D019938:Cyclin D1; D002945:Cisplatin