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  • EXPRESSION  (17)
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  • 11
    Keywords: CANCER ; EXPRESSION ; Germany ; human ; LUNG ; lung cancer ; LUNG-CANCER ; POPULATION ; RISK ; GENE ; GENES ; DRUG ; FAMILY ; GENETIC POLYMORPHISMS ; SEQUENCE ; polymorphism ; POLYMORPHISMS ; PROMOTER ; EFFICACY ; cancer risk ; REGION ; CARRIERS ; VARIANT ; ALLELE ; CHINESE ; CYP3AP1,CYP3A5,CYP3A4,pseudogene,polymorphism,linkage disequilibrium
    Abstract: Genetic polymorphisms of the human CYP3A family affect clinical drug efficacy and may modify cancer risk. CYP3A genes show high sequence similarity that had previously lead to misallocation of CYP3A polymorphisms. Recent studies indicated a high degree of or even complete linkage for certain CYP3A alleles. Reliable LightCycler-based genotyping methods were developed and their degree of linkage in a large Caucasian population (n = 1210) investigated. Strong linkage disequilibrium was confirmed between CYP3A4, CYP3A5, and CYP3AP1 (each at P 〈 10(-5)). Contrary to some previous results claiming complete linkage between the phenotypically relevant CYP3A5(*) 1 and a variant in a pseudogene promoter region CYP3AP1(*) 1, we found among 428 controls (15 of 66) and 782 lung cancer cases (25 of 115) approximately 22% of CYP3AP1(*) 1/(*) 3 carriers to be homozygous for CYP3A5(*) 3. We conclude that contrary to previous assumptions, the CYP3AP1 genotype is not a reliable predictor for CYP3A5 activity. (C) 2004 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 15050738
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  • 12
    Keywords: CANCER ; EXPRESSION ; IN-VITRO ; IONIZING-RADIATION ; radiotherapy ; BLOOD ; Germany ; THERAPY ; TOXICITY ; RISK ; GENE ; GENES ; transcription ; radiation ; PATIENT ; RESPONSES ; DNA ; RISK-FACTORS ; PATTERNS ; DNA-REPAIR ; REPAIR ; risk factors ; prostate cancer ; PROSTATE-CANCER ; PCR ; DAMAGE ; LYMPHOCYTES ; PROBES ; DNA-DAMAGE ; CANCER-PATIENTS ; RT-PCR ; INTENSITY-MODULATED RADIOTHERAPY ; sensitivity ; CANCER PATIENTS ; PERIPHERAL-BLOOD ; DNA repair ; CONSTITUTIVE EXPRESSION ; NORMAL-TISSUE RADIOSENSITIVITY ; PERIPHERAL-BLOOD LYMPHOCYTES ; radiosensitivity ; CLUSTER ; BRCA2 ; GRADE ; CLUSTER-ANALYSIS ; LEVEL ; DNA damage ; cluster analysis ; PROFILES ; EXPRESSION PATTERNS ; CRITERIA ; HUMAN-CELLS ; prospective ; GAMMA-IRRADIATION ; RISK-FACTOR ; SKIN REACTIONS ; peripheral blood ; GENOTOXIC STRESS ; gene expression profiles ; radio-resistance
    Abstract: Purpose: Repair of radiation-induced DNA damage is believed to play a critical role in the development of adverse reactions in radiotherapy patients. Constitutive mRNA expression of repair genes was investigated in such patients to analyze whether expression patterns are predictive for therapy-related acute side effects. Materials and methods: Prostate cancer patients (n = 406) receiving intensity-modulated radiotherapy were recruited in a prospective epidemiological study. Adverse effects were monitored during therapy using common toxicity criteria. For expression analyses, samples from 58 patients were selected according to their observed grade of clinical side effects to radiotherapy. Expression profiles were generated from peripheral blood lymphocytes using customized cDNA-arrays which carried probes for 143 DNA repair or repair-related genes. In addition, expression of selected genes was confirmed by quantitative real-time reverse transcription PCR (RT-PCR). Constitutive mRNA expression profiles were analyzed for predicting acute clinical radiosensitivity or radio-resistance. Results: Cluster analysis identified 19 differentially expressed genes. Many of these genes are involved in DNA double strand break repair. Expression levels of these genes differed up to 7-fold from the mean of all patients whereas expression levels of housekeeping genes varied only up to 2-fold. High expression of the identified genes was associated with a lack of clinical radiation sensitivity thus indicating radio-resistance. Conclusions: Constitutive expression of DNA repair-related genes may affect the development of acute side effects in radiotherapy patients, and high expression levels of these genes seem to support protection from adverse reactions
    Type of Publication: Journal article published
    PubMed ID: 16966187
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  • 13
    Keywords: CANCER ; CELLS ; EXPRESSION ; IN-VITRO ; IONIZING-RADIATION ; radiotherapy ; CELL ; Germany ; PROSTATE ; TOXICITY ; VITRO ; COMMON ; RISK ; GENE ; GENES ; transcription ; radiation ; TIME ; PATIENT ; DNA ; RISK-FACTORS ; INDUCTION ; STRESS ; DNA-REPAIR ; REPAIR ; risk factors ; smoking ; prostate cancer ; PROSTATE-CANCER ; MODULATION ; PCR ; DAMAGE ; LYMPHOCYTES ; DNA-DAMAGE ; CANCER-PATIENTS ; side effects ; CANCER PATIENTS ; real-time PCR ; NUCLEOTIDE EXCISION-REPAIR ; DNA repair ; NORMAL-TISSUE RADIOSENSITIVITY ; PERIPHERAL-BLOOD LYMPHOCYTES ; radiosensitivity ; ONCOLOGY ; GRADE ; quantitative RT-PCR ; REAL-TIME ; development ; ionizing radiation ; DAMAGE RECOGNITION ; LEVEL ; biomarker ; INTERVAL ; analysis ; CRITERIA ; BREAST-CANCER PATIENTS ; USA ; HUMAN-CELLS ; DNA damage response ; INCREASED RISK ; NEVER SMOKERS ; odds ratio ; RISK-FACTOR ; PREDICT ; quantitative ; REPAIR GENES ; LYMPHOBLASTOID-CELLS ; GROUP-C PROTEIN
    Abstract: Repair of radiation-induced DNA damage is believed to play a critical role in developing adverse reactions during radiotherapy. Ionizing radiation induces transcription of several DNA repair genes including XPC as a part of the p53-transmitted stress response. XPC gene induction was measured to analyze whether it predicts occurrence of therapy-related acute side effects. Prostate cancer patients (n = 406) receiving radiotherapy were monitored for development of acute adverse effects using common toxicity criteria. For gene induction analysis, lymphocytes from 99 patients were selected according to their observed grade of clinical side effects. Cells were irradiated in vitro with 5 Gy and analyzed after 4 hr for XPC gene induction using reverse transcription and quantitative real-time PCR. Analysis of modulation of XPC induction by personal, clinical or lifestyle factors was included. Inter-individual induction of XPC expression by ionizing radiation varied up to 20-fold (0.29-5.77) and was significantly higher in current or exsmokers than in never-smokers (p value: 0.008). Patients with XPC induction above the 90th percentile compared to those with lower induction levels were at increased risk of suffering from adverse reactions during radiotherapy (odds ratio 5.3, 95% confidence interval 1.2-24.5; adjusted for smoking). In summary, XPC mRNA levels induced by ionizing radiation were shown for the first time to be strongly affected by smoking and to be associated with an approximately 5-fold increased risk for developing acute side effects of radiotherapy. The predictive value of DNA damage-induced XPC levels as a possible biomarker for radiosensitivity has to be further investigated. (c) 2007 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 17657713
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  • 14
    Keywords: APOPTOSIS ; CANCER ; CELLS ; EXPRESSION ; IN-VITRO ; IONIZING-RADIATION ; radiotherapy ; PATHWAY ; TOXICITY ; COHORT ; GENE ; GENE-EXPRESSION ; radiation ; MESSENGER-RNA ; mechanisms ; BREAST-CANCER ; LYMPHOCYTES ; CANCER-PATIENTS ; EPSTEIN-BARR-VIRUS ; Epstein-Barr virus ; ONCOLOGY ; immortalization ; BLOOD-CELLS ; Individual radiosensitivity ; Ionizing irradiation ; LYMPHOBLASTOID CELL-LINES ; mRNA expression ; White blood cell subtypes
    Abstract: The majority of patients tolerate radiotherapy well, but some of them suffer from severe side effects. To find genes possibly predictive for radiosensitivity, mRNA profiles were generated before and 6h after in vitro irradiation with 5Gy. We analyzed lymphocytes from four head and neck and eight breast cancer patients with strong acute radiation toxicity and from 12 matching normal reacting patients in a blind study. Expression was also measured in lymphocyte subpopulations and Epstein-Barr transformed lymphocytes. Radiation response in whole lymphocyte populations was most similar to that of B cells. In peripheral blood lymphocytes of all patients; 153 genes were identified which were statistically significantly altered by a fold change of more than 50% by irradiation. The signatures of radio-responsive genes differed tremendously between primary and transformed cells. Pathway analysis revealed genes involved in p53 signalling, cell cycle control and apoptosis in response to radiation in primary lymphocytes. In these cells, a set of 67 radiation-induced genes was identified capable of differentiating between severe radiosensitive and normal reacting patients. More than one third of such classifying genes belong to the group of apoptosis or cell cycle regulating genes. The classifying potential of the expression signature has now to be validated in further patient cohorts.
    Type of Publication: Journal article published
    PubMed ID: 21236564
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  • 15
    Keywords: EXPRESSION ; tumor ; BLADDER-CANCER ; inactivation ; DAMAGE ; REVEALS ; HYPERMETHYLATION ; HYPOMETHYLATION ; EXCISION ; GLYCOSYLASE
    Abstract: Aberrant promoter methylation of different DNA repair genes has a critical role in the development and progression of various cancer types, including head and neck squamous cell carcinomas (HNSCCs). A systematic analysis of known human repair genes for promoter methylation is however missing. We generated quantitative promoter methylation profiles in single CpG units of 160 human DNA repair genes in a set of DNAs isolated from fresh frozen HNSCC and normal tissues using MassARRAY technology. Ninety-eight percent of these genes contained CpG islands (CGIs) in their promoter region; thus, DNA methylation is a potential regulatory mechanism. Methylation data were obtained for 145 genes, from which 15 genes exhibited more than a 20% difference in methylation levels between tumor and normal tissues, manifested either as hypermethylation or as hypomethylation. Analyses of promoter methylation with mRNA expression identified the DNA glycosylase NEIL1 (nei endonuclease VIII-like 1) as the most prominent candidate gene. NEIL1 promoter hypermethylation was confirmed in additional fresh frozen HNSCC samples, normal mucosa, HNSCC cell lines and primary human skin keratinocytes. The investigation of laser-microdissected tissues further substantiated increased methylation levels in tumor versus matched non-tumor cells. Immunohistological analysis revealed significantly less NEIL1 protein expression in tumor tissues. 5-Aza-2'-deoxycytidine treatment and DNMT1 knockdown resulted in the re-expression of NEIL1 in HNSCC cell lines, which initially carried hypermethylated promoter regions. In conclusion, our results suggest that DNA methylation contributes to the downregulation of NEIL1 expression and might thus have a role in modulating the response to therapies of HNSCC.
    Type of Publication: Journal article published
    PubMed ID: 22286769
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  • 16
    Keywords: EXPRESSION ; radiotherapy ; DNA ; IMPACT ; GENE ; GENE-EXPRESSION ; gene expression ; genetics ; REPAIR ; DNA-REPAIR ; heredity ; DNA repair ; side effects ; USA ; TOXICOLOGY ; PREDICT ; LEVEL ; mutagen
    Type of Publication: Meeting abstract published
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  • 17
    Keywords: CANCER ; CELLS ; EXPRESSION ; CELL ; Germany ; DISTINCT ; PROTEIN ; LINES ; DNA ; recombination ; CELL-LINES ; BREAST ; breast cancer ; BREAST-CANCER ; DNA-REPAIR ; MUTATION ; REPAIR ; RATES ; CELL-LINE ; LINE ; inactivation ; DAMAGE ; INSTABILITY ; DNA-DAMAGE ; EXCHANGE ; STABILITY ; PHENOTYPE ; KINETICS ; cell lines ; RELATIVES ; CLUSTERS ; DNA repair ; protein expression ; HOMOLOGOUS RECOMBINATION ; CLUSTER ; RE ; BRCA2 ; CAPACITY ; INCREASE ; REARRANGEMENT ; MUTATION CARRIERS ; haploinsufficiency ; CHROMOSOMAL INSTABILITY ; IMPAIRMENT ; LEVEL ; DNA damage ; HUMAN-CELLS ; GAMMA-IRRADIATION ; genomic ; CROSS-LINKS ; DEFECT ; FAMILIAL BREAST ; familial breast cancer ; FANCONI-ANEMIA ; HISTONE H2AX ; homologous ; MESSENGER-RNA DECAY ; RAD51 ; recombination repair ; STRAND BREAKS
    Abstract: The BRCA2 protein is involved in the maintenance of genomic stability through its key role in homologous recombination repair of DNA double strand breaks. Biallelic inactivation of BRCA2 leads to a defect in DNA repair and is associated with a chromosomal instability phenotype. Recent studies on familial breast cancer clusters revealed chromosomal rearrangements and higher rates of sister chromatid exchanges also in heterozygous BRCA2 mutation carriers. In the present study, lymphoblastoid cell lines of heterozygous BRCA2 mutation carriers and of wildtype relatives were compared with regard to BRCA2 mRNA and protein expression and capacity to repair DNA damage induced by gamma-irradiation and mitomycin C. BRCA2+/- cells showed lower amounts of the full-length BRCA2 protein compared to BRCA2+/+ cells. The kinetics of gamma-H2AX protein level revealed distinct defects in DNA double strand break repair in the BRCA2+/- cells. These results are indicative of a haploinsufficiency phenotype in BRCA2+/- cells, suggesting that reduced amounts of functional BRCA2 protein in BRCA2+/- carriers are insufficient for an efficient repair of DNA double strand breaks, a condition that could contribute to the impairment of genomic stability. (c) 2006 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 16448746
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