title: Role of ERCC1 promoter hypermethylation in drug resistance to cisplatin in human gliomas.
abstract: Overexpression of ERCC1 mRNA is associated with drug resistance to cisplatin in human gliomas, but the role of the ERCC1 promoter in drug resistance has not been demonstrated. We have used sodium bisulfite sequencing to compare ERCC1 promoter methylation patterns in cisplatin-sensitive and cisplatin-resistant glioma cells. The levels of ERCC1 DNA methylation, mRNA and protein in 32 human glioma samples were examined by methylation specific PCR, real-time RT-PCR and immunohistochemistry, respectively. Meanwhile, cisplatin sensitivities to these human glioma samples were tested by histoculture drug response assay. Hypermethylation was observed in the upstream 5Kb region of the ERCC1 promoter of cisplatin-sensitive glioma cell lines. ERCC1 DNA methylation levels were highly variable in 32 human glioma samples ranging from 0.1 to 0.87, which have shown significant difference between cisplatin-sensitive samples and cisplatin-resistant samples (p < 0.05). The relative expression levels of ERCC1 mRNA in 32 glioma samples were also variable from 0.01 to 5.71. No detectable or low expression of ERCC1 protein was shown in 7 glioma samples. ERCC1 promoter methylation was inversely correlated to mRNA expression (r = -0.903 p = 0.001) as well as protein expression (r = -0.884 p = 0.001). Moreover, ERCC1 mRNA expression was significantly associated with protein levels (r = 0.840 p = 0.001). In summary, the aberrant CpG island methylation in ERCC1 promoter region exists in human glioma cell lines as well as clinical glioma samples. ERCC1 DNA methylation could regulate the expression of downstream mRNA and protein, and was associated with cisplatin chemosensitivity.
authors.affiliation: State Key Laboratory of Oncology in Southern China, and Department of Neurosurgery/Neuro-oncology, Cancer Center, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Hua-Yun
authors.initials: HY
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Oncology in Southern China, and Department of Neurosurgery/Neuro-oncology, Cancer Center, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Cui-Jie
authors.initials: CJ
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Oncology in Southern China, and Department of Neurosurgery/Neuro-oncology, Cancer Center, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Fu-Rong
authors.initials: FR
authors.lastname: Chen
authors.affiliation: Department of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, China.
authors.forename: Aij-Lie
authors.initials: AL
authors.lastname: Kwan
authors.affiliation: State Key Laboratory of Oncology in Southern China, and Department of Neurosurgery/Neuro-oncology, Cancer Center, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Zhong-Ping
authors.initials: ZP
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000188:drug therapy / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002945:Cisplatin / Q000627:therapeutic use; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D004720:Endonucleases / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D005910:Glioma / Q000188:drug therapy / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; C071447:ERCC1 protein, human; D004720:Endonucleases; D002945:Cisplatin