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: 2.3). 07/2012; 28(4):1146-52. DOI: 10.3892/or.2012.1912
Source: PubMed


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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Available from: Banno Kouji, May 03, 2014
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    • "Several reports have suggested that the aggressive nature of human cervical carcinoma is related to a number of molecular abnormalities, including inactivation of various tumor suppressor genes and activation of various oncogenes [4]. The development of novel targeted therapies for cervical cancer has been hindered by the lack of sufficient genetic and epigenetic data concerning its pathogenesis and the paucity of targets [5], [6], [7], [8]. "
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