Deficiency in DNA mismatch repair increases the rate of telomere shortening in normal human cells

Méndez-Bermúdez, Aarón; Royle, Nicola J.

doi:10.1002/humu.21522

Cited by 33 publications

(33 citation statements)

References 53 publications

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“…Furthermore it was demonstrated, that MLH1 gene is silenced by promoter methylation in TS1 cells [74]. Defects in DNA Mismatch Repair (MMR) are not only associated with various types of cancer, but also with an elevated telomere shortening [75]. This is also supported by our results, where a strong negative correlation of telomere length and MLH1 methylation could be identified.…”

Section: Discussionsupporting

confidence: 84%

EGCG Containing Combined Dietary Supplement Affects Telomeres and Epigenetic Regulation

Pointner¹,

Magnet²,

Tomeva³

et al. 2017

J Nutr Food Sci

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Objective: In vitro and in vivo studies in rodents have demonstrated many health promoting properties of individual phytochemicals including antioxidative and chemopreventive effects. Recently combination of substances is claimed to enhance activity.The objective of this study was to investigate health benefits of a daily consumption of a combination of a large variety of phytochemicals (TimeBlock ® ). To assess potential changes we analyzed specific biomarkers that are associated with aging, oxidative stress and DNA stability: Methylation of LINE-1, c-Myc, IL-6, MLH1, DNMT1, ITGA2B and telomere length. Methods:For this study 110 healthy participants of both sexes between 31-76 years were recruited, 101 subjects were included in further analysis. A small reference group (n=20) without intervention within the same age interval served as control. Participants received a plant based dietary supplement (TimeBlock ® ) for 6 months by oral administration. Ingredients included extracts from green tea (EGCG), wheatgrass (tocotrienols), barley grass (folic acid), tomatoes (lycopene), tagetes (zeaxanthin, lutein), algae, shiitake mushrooms (vitamin D) and grape seeds (resveratrol). Capillary blood samples were collected from all participants before administration and within 6 days after the end of the study period following DNA extraction, bisulfite conversion and qPCR as well as high resolution melting curve analysis addressing analysis of LINE-1, c-Myc, IL-6, MLH1, DNMT1, ITGA2B and telomere length. Nutrition, lifestyle and health status were assessed with a standardized food and lifestyle questionnaire. Results and discussion:Our results confirmed the positive effect of plant derived antioxidants on telomeres and inflammation frequency. An age-specific drift of analyzed markers could be observed. While methylation of c-Myc-a key factor in telomerase regulation-was not affected by administration, total telomere length showed a significant increase, which we suggest to be linked with an increased cell turnover and accelerated apoptosis of senescent or mutated cells without enhancing telomerase activity. Further, methylation of mismatch repair protein gene MLH1 showed a strong negative correlation with telomere length, supporting the influence of MMR on telomere regulation. Conclusion:The results of the present study indicate that a combined administration of a variety of phytochemicals can be a potential preventive and therapeutic agent, as each substance exhibits different modes of action and in combination, health promoting effects could be potentiated. Addressing different mechanisms of aging, specific phytochemicals could be used as new therapeutic approach against age-related diseases.

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Section: Discussionsupporting

confidence: 84%

EGCG Containing Combined Dietary Supplement Affects Telomeres and Epigenetic Regulation

Pointner¹,

Magnet²,

Tomeva³

et al. 2017

J Nutr Food Sci

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“…Deficiency in MLH1 and MSH2 mismatch repair genes might cause a high background mutation rate in CCRF-CEM cells41. This deficiency leads to telomere shortening as also observed in human fibroblasts42. The background mutation rate was further increased in CEM/ADR5000 cells under drug selection pressure.…”

Section: Discussionmentioning

confidence: 94%

Genomic and transcriptomic profiling of resistant CEM/ADR-5000 and sensitive CCRF-CEM leukaemia cells for unravelling the full complexity of multi-factorial multidrug resistance

Kadioglu

Cao

Kosyakova

et al. 2016

Sci Rep

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We systematically characterised multifactorial multidrug resistance (MDR) in CEM/ADR5000 cells, a doxorubicin-resistant sub-line derived from drug-sensitive, parental CCRF-CEM cells developed in vitro. RNA sequencing and network analyses (Ingenuity Pathway Analysis) were performed. Chromosomal aberrations were identified by array-comparative genomic hybridisation (aCGH) and multicolour fluorescence in situ hybridisation (mFISH). Fifteen ATP-binding cassette transporters and numerous new genes were overexpressed in CEM/ADR5000 cells. The basic karyotype in CCRF-CEM cells consisted of 47, XX, der(5)t(5;14) (q35.33;q32.3), del(9) (p14.1), +20. CEM/ADR5000 cells acquired additional aberrations, including X-chromosome loss, 4q and 14q deletion, chromosome 7 inversion, balanced and unbalanced two and three way translocations: t(3;10), der(3)t(3;13), der(5)t(18;5;14), t(10;16), der(18)t(7;18), der(18)t(21;18;5), der(21;21;18;5) and der(22)t(9;22). CCRF-CEM consisted of two and CEM/ADR5000 of five major sub-clones, indicating genetic tumor heterogeneity. Loss of 3q27.1 in CEM/ADR5000 caused down-regulation of ABCC5 and ABCF3 expression, Xq28 loss down-regulated ABCD1 expression. ABCB1, the most well-known MDR gene, was 448-fold up-regulated due to 7q21.12 amplification. In addition to well-known drug resistance genes, numerous novel genes and genomic aberrations were identified. Transcriptomics and genetics in CEM/AD5000 cells unravelled a range of MDR mechanisms, which is much more complex than estimated thus far. This may have important implications for future treatment strategies.

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“…It has been observed that MMR-deficient cell lines and colon tumors show high mutation frequencies at telomere ends, leading to accelerated telomere shortening. [38][39][40][41] The effect of an increased telomereshortening rate is likely to require early activation of telomerase in such tumors. As hypothesized above, the presence of the A allele of rs2075786 might imply even earlier activation of telomerase.…”

Section: Discussionmentioning

confidence: 99%

Genetic variant in the telomerase gene modifies cancer risk in Lynch syndrome

et al. 2012

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Lynch syndrome (LS) is an inherited cancer-predisposing disorder caused by germline mutations in the mismatch repair (MMR) genes. The high variability in individual cancer risk observed among LS patients suggests the existence of modifying factors. Identifying genetic modifiers of risk could help implement personalized surveillance programs based on predicted cancer risks. Here we evaluate the role of the telomerase (hTERT) rs2075786 SNP as a cancer-risk modifier in LS, studying 255 and 675 MMR gene mutation carriers from Spain and the Netherlands, respectively. The study of the Spanish sample revealed that the minor allele (A) confers increased cancer risk at an early age. The analysis of the Dutch sample confirmed the association of the A allele, especially in homozygosity, with increased cancer risk in mutation carriers under the age of 45 (relative risk LScao45_AA ¼ 2.90; 95% confidence interval ¼ 1.02-8.26). Rs2075786 is associated with colorectal cancer (CRC) risk neither in the general population nor in non-Lynch CRC families. In silico studies predicted that the SNP causes the disruption of a transcription binding site for a retinoid receptor, retinoid X receptor alpha, probably causing early telomerase activation and therefore accelerated carcinogenesis. Notably, cancer-affected LS patients with the AA genotype have shorter telomeres than those with GG. In conclusion, MMR gene mutation carriers with hTERT rs2075786 are at high risk to develop a LS-related tumor at an early age. Cancer-preventive measures and stricter cancer surveillance at early ages might help prevent or early detect cancer in these mutation carriers.

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Deficiency in DNA mismatch repair increases the rate of telomere shortening in normal human cells

Cited by 33 publications

References 53 publications

EGCG Containing Combined Dietary Supplement Affects Telomeres and Epigenetic Regulation

EGCG Containing Combined Dietary Supplement Affects Telomeres and Epigenetic Regulation

Genomic and transcriptomic profiling of resistant CEM/ADR-5000 and sensitive CCRF-CEM leukaemia cells for unravelling the full complexity of multi-factorial multidrug resistance

Genetic variant in the telomerase gene modifies cancer risk in Lynch syndrome

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