title: ABCC5, ERCC2, XPA and XRCC1 transcript abundance levels correlate with cisplatin chemoresistance in non-small cell lung cancer cell lines.
abstract: BACKGROUND
  Although 40-50% of non-small cell lung cancer (NSCLC) tumors respond to cisplatin chemotherapy, there currently is no way to prospectively identify potential responders. The purpose of this study was to determine whether transcript abundance (TA) levels of twelve selected DNA repair or multi-drug resistance genes (LIG1, ERCC2, ERCC3, DDIT3, ABCC1, ABCC4, ABCC5, ABCC10, GTF2H2, XPA, XPC and XRCC1) were associated with cisplatin chemoresistance and could therefore contribute to the development of a predictive marker. Standardized RT (StaRT)-PCR, was employed to assess these genes in a set of NSCLC cell lines with a previously published range of sensitivity to cisplatin. Data were obtained in the form of target gene molecules relative to 106 beta-actin (ACTB) molecules. To cancel the effect of ACTB variation among the different cell lines individual gene expression values were incorporated into ratios of one gene to another. Each two-gene ratio was compared as a single variable to chemoresistance for each of eight NSCLC cell lines using multiple regression. In an effort to validate these results, six additional lines then were evaluated.
  
  
  RESULTS
  Following validation, single variable models best correlated with chemoresistance (p < 0.001), were ERCC2/XPC, ABCC5/GTF2H2, ERCC2/GTF2H2, XPA/XPC and XRCC1/XPC. All single variable models were examined hierarchically to achieve two variable models. The two variable model with the highest correlation was (ABCC5/GTF2H2, ERCC2/GTF2H2) with an R2 value of 0.96 (p < 0.001).
  
  
  CONCLUSIONS
  These results provide markers suitable for assessment of small fine needle aspirate biopsies in an effort to prospectively identify cisplatin resistant tumors.
authors.affiliation: Department of Medicine, Medical College of Ohio, 3055 Arlington Ave., Toledo, OH 43699, USA. dweaver@mco.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Weaver
authors.forename: Erin L
authors.initials: EL
authors.lastname: Crawford
authors.forename: Kristy A
authors.initials: KA
authors.lastname: Warner
authors.forename: Fadel
authors.initials: F
authors.lastname: Elkhairi
authors.forename: Sadik A
authors.initials: SA
authors.lastname: Khuder
authors.forename: James C
authors.initials: JC
authors.lastname: Willey
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D004247:DNA / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008957:Models, Genetic; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D015203:Reproducibility of Results; D014158:Transcription, Genetic / Q000235:genetics*; D000076105:X-ray Repair Cross Complementing Protein 1; D051760:Xeroderma Pigmentosum Group A Protein / Q000235:genetics*; D051759:Xeroderma Pigmentosum Group D Protein / Q000235:genetics*
chemical_list: D002945:Cisplatin; D004247:DNA; D004268:DNA-Binding Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; D051760:Xeroderma Pigmentosum Group A Protein; D051759:Xeroderma Pigmentosum Group D Protein; C120809:ABCC5 protein, human; C497314:XPA protein, human; C000619371:XRCC1 protein, human; C497292:ERCC2 protein, human