title: DNA methylation-mediated caspase-8 downregulation is associated with anti-apoptotic activity and human malignant glioma grade.
abstract: The methylation-mediated silencing of tumor suppressors, including key apoptosis-related genes plays an important role in the pathogenesis and therapeutic resistance in human cancer. In this study, we aimed to elucidate the role and mechanisms of resistance to apoptosis with caspase-8 gene downregulation in human malignant glioma. Reverse transcription-polymerase chain reaction (RT-PCR) and methylation-specific PCR (MSP) were used to examine caspase-8 expressoin at the mRNA level and gene methylation status in normal brain tissue, glioma tissue and cancer cell lines. Caspase-8 protein kinase activity was measured by caspase-8 colorimetric assays; cell apoptosis was examined by Annexin V/propidium iodide (PI) staining; the rates of tumor cell apoptosis were detected by flow cytometry. Our results revealed that caspase-8 gene silencing may result from the methylation of its gene promoter in human glioma tissues. The expression of caspase-8 at the mRNA level was significantly associated with the grade of human glioma. In certain human cancer cell lines, the expression at the mRNA level, protein kinase activity and tumor cell anti-apoptotic activity and resistance were related to the methylation status of the caspase-8 gene promoter. Thus, the caspase-8 gene methylation status may be used as an indicator for the early diagnosis of human malignant glioma. Combination therapy with demethylation reagents may overcome therapeutic resistance in the same malignancy.
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yueqiu
authors.initials: Y
authors.lastname: Teng
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yu-Cui
authors.initials: YC
authors.lastname: Dong
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Zhaoyu
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zou
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xie
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, The Third Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150040, P.R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Su
authors.affiliation: Central Laboratory of Blood Cancer, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China.
authors.forename: Fenglin
authors.initials: F
authors.lastname: Cao
authors.affiliation: Department of Neurosurgery, The Third Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150040, P.R. China.
authors.forename: Hua
authors.initials: H
authors.lastname: Jin
authors.affiliation: Department of Immunology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Huan
authors.initials: H
authors.lastname: Ren
mesh_terms: D000328:Adult; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics*; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D053181:Caspase 8 / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D018899:CpG Islands; D019175:DNA Methylation; D004789:Enzyme Activation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D005910:Glioma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D017304:Annexin A5; D012333:RNA, Messenger; D053181:Caspase 8