Article

Association of epigenetic inactivation of the WRN gene with anticancer drug sensitivity in cervical cancer cells.

Department of Obstetrics and Gynecology, School of Medicine, Keio University, Tokyo, Japan.
Oncology Reports (impact factor: 1.84). 07/2012; 28(4):1146-52. DOI:10.3892/or.2012.1912 pp.1146-52
Source: PubMed

ABSTRACT The Werner (WRN) gene codes for a DNA helicase that contributes to genomic stability and has been identified as the gene responsible for progeria. Recent studies have shown reduced WRN expression due to aberrant DNA hypermethylation in cancer cells. Furthermore, WRN expression is thought to affect sensitivity to DNA topoisomerase I inhibitors in cancer therapy. In this study, we examined the relationship between aberrant DNA hypermethylation of WRN and the sensitivity of cervical cancer cells to anticancer drugs. DNA was extracted from samples from 22 patients with primary cervical cancer and 6 human cervical cancer-derived cell lines. Aberrant DNA hypermethylation was analyzed by methylation-specific PCR. WRN expression in cultured cells before and after addition of 5-aza-2-deoxycytidine, a demethylating agent, was examined using RT-PCR. The sensitivity of cells to anticancer drugs was determined using a collagen gel droplet embedded culture drug sensitivity test (CD-DST). siRNA against WRN was transfected into a cervical cancer-derived cell line with high WRN expression. Changes in drug sensitivity after silencing WRN were determined by CD-DST. Aberrant DNA hypermethylation and decreased expression of WRN were detected in 7/21 cases of primary cervical cancer and in two cervical cancer-derived cell lines. These two cell lines showed high sensitivity to CPT-11, a topoisomerase I inhibitor, but became resistant to CPT-11 after treatment with 5-aza-2-deoxycytidine. Transfection of siRNA against WRN increased the sensitivity of the cells to CPT-11. Aberrant DNA hypermethylation of WRN also increased the sensitivity of cervical cancer cells to CPT-11. Therefore, epigenetic inactivation of this gene may be a biomarker for selection of drugs for the treatment of cervical cancer. This is the first report to show a relationship between the methylation of the WRN gene and sensitivity to CPT-11 in gynecological cancers.

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Keywords

22 patients
 
aberrant DNA hypermethylation
 
anticancer drugs
 
cancer cells
 
cancer therapy
 
cervical cancer
 
cervical cancer cells
 
cervical cancer-derived cell line
 
cervical cancer-derived cell lines
 
culture drug sensitivity test
 
cultured cells
 
DNA helicase
 
DNA topoisomerase
 
drug sensitivity
 
epigenetic inactivation
 
gynecological cancers
 
primary cervical cancer
 
Recent studies
 
two cell lines
 
WRN gene