A Study of Radiation-Induced Telomere Instability Using Multiplex Ligation-Dependent Probe Amplification (MLPA)

The integrity of the chromosomes for two WIL2-derived lymphoblastoid cell lines (TK6 and WTK1) in the presence and absence of ionizing radiation was analyzed by Multiplex Ligation-Dependent Probe Amplification (MLPA). The TK6 cell line has the native p53 tumor-suppressor gene, whereas WTK1 cells contain a p53 mutation. Each cell line was isolated pre- and post-irradiation (2 and 3 Gy) and analyzed by MLPA. The impact of irradiation on these two cell lines was investigated using probes that target specific regions on chromosomes associated with subtelomeric regions. Results indicate that WTK1 and TK6 are impacted differently after irradiation, and that each cell line presents its own unique MLPA profile. The most notable differences are the appearance of a number of probes in the post-irradiated MLPA profile that are not present in the controls, and two unique probe signals only seen in WTK1 cells. These results build on our previous studies that indicate how different human cell lines can be affected by radiation in significantly different ways depending on the presence or absence of wild type p53.

Direct Correlation among Telomere Length, Cellular Aging, and Rejuvenation Effects of Honey Child Powder

Purpose: Telomere length (TL) is an indicator of age;however, hormonal influences complicate individual aging. It remains unclear whether TL shortening is a direct factor in both individual and cellular aging. Therefore, we examined the direct relationship between TL and cellular senescence at the cellular level. Methods: Telomerase activity, TL, and gene expression were measured in cultured human lung-, fetal-, and skin-derived fibroblasts, human skin keratinocytes, and telomerase reverse transcriptase (TERT) gene-immortalized cells using detection kits, Cawthon’s method, and reverse transcription-quantitative polymerase chain reaction, respectively. Novel substances that elongate telomeres were screened to confirm cell rejuvenation effects. Results: Long-term cell culture of TIG-1-20 normal human fibroblasts resulted in TL shortening, decreased division rate, and senescence progression, whereas in OUMS-36T-2 cells, TL elongation via TERT gene transfer increased the division rate, reduced endoplasmic reticulum stress, and upregulated genes associated with young individuals, indicating that cellular rejuvenation occurs via TL elongation. In addition, a honey child powder (HCP) extract was found through screening, and the HCP extract strongly suppressed the menin gene, resulting in increased telomerase activity and extended cell lifespan. Upon addition of the HCP extract to skin fibroblasts, gene expression of moisturizing components, including collagen, hyaluronic acid, and elastin, increased, and exhibited a rejuvenating effect with an increase in elastin amount. Conclusions: TL elongation or shortening is involved in cell proliferation rate and cellular aging, and TL elongation rejuvenates cells. In addition, HCP extract has a rejuvenating effect on cells and is expected to be a rejuvenating compound.

Association between Dietary Collagen Consumption and Telomere Length: National Health and Nutrition Examination Survey

Background: Bioactive peptides derived from hydrolyzed collagen have broad physiological functions and beneficial effects on human health, ranging from reducing skin aging to modifying lipid metabolism. Telomere length shortening is an established biomarker of cellular aging. It is not known if collagen consumption is associated with telomere length protection. Our purpose was to investigate the relationship between dietary collagen consumption and telomere length in a nationally representative US adult population. Methods: We analyzed the data of 6173 adults aged 20 - 84 from the National Health and Nutrition Examination Survey (NHANES) 1999-2002. Multivariable linear regression and a generalized additive model with smoothing plot were used to assess the association between the total collagen consumption and log-transformed leukocyte telomere length (LTL). Results: Compared with the lowest quartile of total collagen (Q1), we found that the second quartile of collagen (Q2) consumption (1.36 - 3.40 g/1000kcal) was positively associated with telomere length (β: 0.017;95% CI: 0.006, 0.028;P = 0.022) in the females while no association in the males (β: −0.003;95% CI: −0.019, 0.012;P = 0.678) and overall population (β: 0.008;95% CI: −0.002, 0.018;P = 0.141). The association in the females is nonlinear with an inflection point of 2.5 g/1000kcal (P for non-linearity: Conclusion: In conclusion, moderate dietary collagen has a positive and nonlinear association with telomere length in US females, while no significant associations were found in the males and the overall population.

Hematopoietic stem cell transplantation of aplastic anemia by relative with mutations and normal telomere length: A case report

BACKGROUND Immunosuppressive therapy and matched sibling donor hematopoietic stem cell transplantation(MSD-HSCT)are the preferred treatments for aplastic anemia(AA).CASE SUMMARY In this report,we describe a 43-year-old male patient with severe AA who carried BRIP1(also known as FANCJ),TINF2,and TCIRG1 mutations.Screening of the family pedigree revealed the same TINF2 mutation in his mother and older brother,with his older brother also carrying the BRIP1 variant and demonstrating normal telomere length and hematopoietic function.The patient was successfully treated with oral cyclosporine A,eltrombopag,and acetylcysteine,achieving remission 4 years after receiving MSD-HSCT from his older brother.CONCLUSION This case provides a valuable clinical reference for individuals with suspected pathogenic gene mutations,normal telomere length,and hematopoietic function,highlighting them as potential donors for patients with AA.

Telomere and telomerase in chronic liver disease and hepatocarcinoma

The pathogenesis of liver cirrhosis is not completely elucidated.Although in the majority of patients,the risk factors may be identified in B and C viral hepatitis,alcohol intake,drugs or fatty liver disease,there is a small percentage of patients with no apparent risk factors.In addition,the evolution of chronic liver disease is highly heterogeneous from one patient to another.Among patient with identical risk factors,some rapidly progress to cirrhosis and hepatocellular carcinoma(HCC)whereas others have a benign course.Therefore,a genetic predisposition may contribute to the development of cirrhosis and HCC.Evidence supporting the role of genetic factors as a risk for cirrhosis has been accumulating during the past years.In addition to the results from epidemiological studies,polymorphisms studies and data on twins,the concept of telomere shortening as a genetic risk factor for chronic liver disease and HCC has been proposed.Here we review the literature on telomerase mutations,telomere shortening and liver disease including hepatocellular carcinoma.

Telomere erosion is independent of microsatellite instability but related to loss of heterozygosity in gastric cancer

AIM To correlate the length of the telomere to microsatellite instability (MSI) and loss of heterozygosity (LOH) of APC, MCC and DCC genes in gastric carcinomas.METHODS Telomeric restriction fragment (TRF) length of gastric cancer was measured with Southern blot. LOH of APC, MCC and DCC genes, microsatellite instability (MSI) and frameshift mutation of hMSH6, TGF-βR Ⅱ and BAX genes were analyzed by PCR-based methods.RESULTS Sixty-eight cases of sporadic gastric carcinoma were studied for MSI using five microsatellite markers. MSI in at least one locus was detected in 17 (25%) of 68 tumors analyzed. Frameshift mutations of hMSH6, TGF-βR Ⅱ and BAX were detected in 2,6 and 3 of gastric carcinomas respectively showing high MSI (≥ 2 loci, n = 8), but none was found in those showing Iow MSI (only one locus, n = 9) or MSS (tumor lacking MSI or stable, n = 51). Thirty-five cases, including all high MSI and Iow MSl, were studied for TRF. The mean TRF length was not correlated with clinicopathological parameters.No association was observed between TRF length and MSI or frameshift mutation. On the contrary, LOH at the DCC locus was related to telomere shortening (P＜ 0.01). This tendency was also observed in APC and MCC genes,although there was no statistical significance.CONCLUSION The development of gastric cancer can arise through two different genetic pathways. In high MSI gastric cancers, defective mismatch repair allows mutations to accumulate and generate the high MSI phenotype. In gastric cancers showing either Iow MSI or MSS, multiple deletions may represent the LOH pathway.Telomere erosion is independent of high MSI phenotype but related to the LOH pathway in gastric cancer.

Influence of the h TERT rs2736100 polymorphism on telomere length in gastric cancer

AIM: To investigate the functional consequences of rs2736100 polymorphism in telomere length and examine its link to gastric cancer risk.METHODS: Telomere length and human telomerase reverse transcriptase(h TERT) m RNA expression were measured in 35 gastric cancer tissues and 5 cell lines and correlated to rs2736100 polymorphism. The relationship between rs2736100 polymorphism and the risk of gastric cancer were examined in 243 gastric cancer patients and 246 healthy individuals.RESULTS: The rs2736100 A allele carrier is closely associated with reduced h TERT m RNA expression and shortened telomere length in gastric cancer tissue and cell lines. When gastric cancers were stratified by histological subtype,telomere length and h TERT m RNA levels were significantly increased in those with the C/C genotype in intestinal-type gastric cancer,but not in diffuse-type gastric cancer. Interestingly,there was no significant difference in the genotype and allele frequencies of the rs2736100 polymorphism between the patients with gastric cancer and healthy controls.CONCLUSION: The rs2736100 polymorphism of the h TERT gene is involved in the regulation of h TERT expression and telomere length,but not in the risk of gastric cancer.

Telomere,telomerase and digestive cancer

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Telomeres,telomerase and colorectal cancer

Colorectal cancer(CRC)is the third most common cancer worldwide and,despite improved treatments,is still an important cause of cancer-related deaths.CRC encompasses a complex of diseases arising from a multistep process of genetic and epigenetic events.Besides heterogeneity in the molecular and biological features of CRC,chromosomal instability is a hallmark of cancer and cancer cells may also circumvent replicative senescence and acquire the ability to sustain unlimited proliferation.Telomere/telomerase interplay is an important mechanism involved in both genomic stability and cellular replicative potential,and its dysfunction plays a key role in the oncogenetic process.The erosion of telomeres,mainly because of cell proliferation,may be accelerated by specific alterations in the genes involved in CRC,such as APC and MSH2.Although there is general agreement that the shortening of telomeres plays a role in the early steps of CRC carcinogenesis by promoting chromosomal instability,the prognostic role of telomere length in CRC is still under debate.The activation of telomerase reverse transcriptase(TERT),the catalytic component of the telomerase complex,allows cancer cells to grow indefinitely by maintaining the length of the telomeres,thus favouring tumour formation/progression.Several studies indicate that TERT increases with disease progression,and most studies suggest that telomerase is a useful prognostic factor.Plasma TERT mRNA may also be a promising marker for the minimally invasive monitoring of disease progression and response to therapy.

RELATIONSHIP BETWEEN TELOMERE LENGTH AND RADIOSENSITIVITY IN VARIOUS HUMAN CANCER CELL LINES

Objective： To investigate the relationship between telomere length and radiosensitivity in various human cancer cell lines with the expectation to find a valid and common predictor of radiosensitivity for different cancers. Methods： Eight human cancer cell lines were used, including five human breast cancer cell lines （ZR-75-30, MCF-7, MDA-MB-435S, T-47-D, F539-1590）, two human larynx squamous carcinoma cell lines （Hep-2 and Hep-2R） and a human malignant glioma cell line （U251）. Among them, the radioresistant cell line Hep-2R was isolated and established from a radiosensitive human larynx squamous carcinoma cell line Hep-2 by our center. The radiobiological characteristics of the eight lines were analyzed by the method of colony-forming assay and the radiosensitivity parameters were calculated. Telomere length was analyzed by TRF （mean Telomere Restriction Fragments） length assay. Results： The radioresistance of Hep-2R cell line proved to be stable in long-term passaged cultures as well as in frozen samples. Radiosensitivity parameters are different among those lines. The SF2 values of Hep-2 and U251 are 0.4148 and 0.7520, respectively; The SF2 values of breast cancer cell lines are between those of Hep-2 and U251. The TRF of Hep-2R is 11.12Kb, longer than three times that of its parental counterpart. There is a positive correlation both between SF2 and TRF （r=-0.786, P〈0.05）, and between Do and TRF （r=0.905, P〈0.01）. Conclusion： It is concluded that radiosensitivity and telomere length （TRF） are negatively correlated, TRF could be a valid predictor for radiosensitivity.

Mild oxidative stress is beneficial for sperm telomere length maintenance

AIM:To evaluate telomere length in sperm DNA and its correlation with oxidative stress(normal,mild,severe).METHODS:The study included infertile men(n=112)and age matched fertile controls(n=102).The average telomere length from the sperm DNA was measured using a quantitative real time PCR based assay.Seminal reactive oxygen species(ROS)and 8-Isoprostane(8-IP)levels were measured by chemiluminescence assay and ELISA respectively.RESULTS:Average sperm telomere length in infertile men and controls was 0.609±0.15 and 0.789±0.060,respectively(P<0.0001).Seminal ROS levels in infertile was higher[66.61±28.32 relative light units(RLU)/s/million sperm]than in controls(14.04±10.67RLU/s/million sperm)(P<0.0001).The 8-IP level in infertile men was significantly higher(421.55±131.29pg/mL)than in controls(275.94±48.13 pg/mL)(P<0.001).When correlated to oxidative stress,in normal range of oxidative stress(ROS,0-21.3 RLU/s/million sperm)the average telomere length in cases was 0.663±0.14,in mild oxidative stress(ROS,21.3-35 RLU/s/million sperm)it was elevated(0.684±0.12)and in severe oxidative stress(ROS>35 RLU/s/million sperm)average telomere length was decreased to 0.595±0.15.CONCLUSION:Mild oxidative stress results in lengthening of telomere length,but severe oxidative stress results in shorter telomeres.Although telomere maintenance is a complex trait,the study shows that mild oxidative stress is beneficial in telomere length maintenance and thus a delicate balance needs to be established to maximize the beneficial effects of free radicals and prevent harmful effects of supra physiological levels.Detailed molecular evaluation of telomere structure,its correlation with oxidative stress would aid in elucidating the cause of accelerated telomere length attrition.

Association between Physical Activity and Telomere Length in a North Chinese Population： A China Suboptimal Health Cohort Study

Several studies have demonstrated an association between physical activity and telomere length; however, the association remains inconsistent. A cross-sectional study consisting of 588 participants （375 females, median age of 33.8 years） was carried out to investigate the association between telomere length and physical activity in a general population from North China. The results show that relative telomere length is not significantly different in participants in the northern Chinese population with different levels of physical activity, either in the model only adjusted for age （F = 2.127, P = 0.120） or in the model adjusted for demographics and lifestyle （F = 1.227, P = 0.294）. The gender-stratified analysis also produced insignificant results. Our study confirmed a non-significant association between physical activity and telomere length in the northern Chinese population, which adds to the inconsistent association between physical activity and telomere length across different ethnic populations.

Study of abnormal length of chromosomal telomere in patients with lung cancer

Objective: To study the relationship between carcinogenesis and abnormal chromosomal length in human lung cancer. Methods: Lung cancer tissue and the lung tissue in the surroundings of lung cancer were studied with Southern blot and autoradiography. Results: The length of chromosomal telomere was significantly shorter in lung cancer tissue than in the surrounding tissue of lung cancer (P < 0.05). The length of chromosomal telomere in lung cancer tissue correlated to the pathological grading of lung cancer (P < 0.05) but showed no correlation to the the ofpatients (P > 0.05) .Conclusion: The changes of the length of chromosomal telomere resulting from carcinogenesis is more prominent than that caused by cell division. The length of telomere can serve as one of the criteria in the early diagnosis of certain types of cancer.

Telomeres and Telomerase: Molecular Views and Perspectives

Telomere, the nucleoprotein structure at the end of eukaryotic linear chromosomes is indispensable for maintaining the genome stability. Telomeric DNA loss is apparent with each cell division, which marks an endpoint to the indefinite replication of the cell by causing replicative senescence that may lead to the programmed cell death. The loss of telomere is normal in cell division and as such after 20 - 40 divisions, telomere becomes too short to facilitate the capping function. Telomere uncapping or chromosomal free end causes a potential threat to the genomic stability and thus leads to the accumulation of chromosomal abnormalities that have been known to play a role in aging and cancer. Telomerase, the ribonucleoprotein complex, and its accessory proteins are required to maintain the telomere sequence. Telomerase plays a key role in maintaining the length of telomere by adding G-rich repeat sequences. Its activity has been found to be quite high in the gametes, stem cells and most importantly tumor cells. Almost 85% of tumor cells compensate for telomere loss aided by telomerase-associated protein complex and shelter in complex or telosome. However, 5% - 10% of the cells undergo telomerase-independent mechanism. This review presents the molecular view of the telomere and telomerase along with its associated complex structures. It also discusses its contrasting role in causing cellular senescence and promoting tumorigenesis.

Telomeres:Linking stress and survival,ecology and evolution

Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell divisionand oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular andcellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, wediscuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize currentknowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interestingnew connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices ofphysiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way thatglucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establishand explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found,it provides an explanatory mechanism by which environmental perturbation impacts life history

Estrogen deficiency leads to telomerase inhibition, telomere shortening and reduced cell proliferation in the adrenal gland of mice

雌激素缺乏调停变老，但是内在的机制尚待充分坚定。我们这里报导 aromatase 的指向的混乱在老鼠引起的雌激素缺乏在 vivo 在肾上腺导致 telomerase 活动的重要抑制。基因表示分析证明当雌激素不在时， telomerase 颠倒 transcriptase (TERT ) 基因表示在肾上腺外皮和肾的萎缩与损害房间增长联合被减少。在 c 工具包积极的干细胞被识别在肾的外皮的实质占据。telomeres 的分析表明那雌激素缺乏比那在肾的外皮导致显著地更短的 telomeres 在野类型(WT ) 控制鼠标。为了推进，建立雌激素的原因的效果，我们在这些雌激素缺乏的动物进行了雌激素代替治疗。为 3 个星期的雌激素的管理在雌激素缺乏的老鼠恢复 TERT 基因表示， telomerase 活动和房间增长。因此，我们第一次，那雌激素缺乏在 vivo 在鼠标的肾上腺引起 TERT 基因表示， telomerase 活动， telomere 维护，和房间增长的抑制的数据表演，建议那 telomerase 抑制并且 telomere 弄短可以调停在肾上腺的房间增长拘捕，因此贡献雌激素在生理的条件下面的导致缺乏的老化。

Clinical significance of telomerase and its associate genes expression in the maintenance of telomere length in squamous cell carcinoma of the esophagus

AIM: To observe the interaction between the expression of telomerase activity (TA) and its associate genes in regulation of the terminal restriction fragment length(TRFL) in esophageal squamous cell carcinoma (SCC).METHODS: Seventy-four specimens of esophageal SCC were examined. The TA was measured by telomeric repeat amplification protocol (TRAP) assay, and the associated genes [human telomerase-specific reverse transcriptase (hTERT), hTERC, TP1, c-Myc, TRF1,and TRF2] were detected using RT-PCR method. The TRFL was measured by Telomere Length Assay Kit and Southern blotting. The correlations between the expression of telomerase and its associated genes with the TRFL and survivals were examined.RESULTS: Expressions of the TA, hTERT, hTERC, TP1,c-Myc, TRF1, and TRF2 genes were observed in 85.1%,64.9%, 79.7%, 100.0%, 94.6%, 82.4%, and 91.9% of the tumor tissues, respectively. The TRFL of the tumor and normal esophageal tissues were 2.70±1.42 and 4.93±1.74 kb, respectively (P＜0.0001). The TRFL of the telomerase positive and telomerase negative tumor tissues were 2.72±1.44 and 2.58±1.32 kb, respectively (P = 0.767).The TRFL ratios (TRFLR) of the telomerase positive and telomerase negative tumor tissues were 0.55±0.22 and 0.59±0.41, respectively (P = 0.742). The expression rates of h-TERT (P = 0.0002), hTERC (P＜0.0001), and TRF1(P = 0.002) in the tumor tissues are higher than those of the normal paired tissues. Though TA is markedly activated in tumor tissues (P＜0.0001), its expression is not related to clinicopathological parameters including gender, tumor differentiation, and TNM stages. The cumulative 4-year survival rates of telomerase positive and telomerase negative cases were 35.86% and 31.2%,respectively (P = 0.8442). The cumulative 4-year survival rates of patients with their TRFLR ≤85% and ＞85%were 38.7% and 15.7%, respectively (P = 0.1307).CONCLUSION: Though telomerase expression is not related to tumor stages and prognosis, our data support that the TA increased as the TRFL decreased,probably under the control of hTERT, hTERC, and TRF1.When telomerase expression was activated, only TRF2overexpression persisted to stabilize T-loop formation.Furthermore, as the TRFLR decreased to 85%, a trend of better prognosis was observed. Cox model analysis indicates a higher t/n TRFLR and distant metastasis are independent poorer prognostic factors (P = 0.035 and P = 0.042, respectively).

Effects of cisplatin on telomerase activity and telomere length in BEL-7404 human hepatoma cells

Telomerase activity was inhibited in a dose and time-dependent manner with the treatment of cisplatin for 24, 48, or 72 h in a concentration ranged from 0.8 to 50 1uM in BEL-7404 human hepatoma cells. There were no changes in expression pattern of three telomerase subunits, its catalytic reverse transcriptase subunit (hTERT), its RNA component (hTR) or the associated protein subunit (TP1), after cisplatin treated for 72 h with indicated concentrations. Mean telomere lengths were decreased by the cisplatin treatment. Cell growth inhibition and cell cycle accumulation in G2/M phase were found to be correlated with telomerase inhibition in the present study, but percentages of cell apoptosis did not change markedly during the process.

Ten1p promotes the telomeric DNA-binding activity of Cdc13p： implication for its function in telomere length regulation

在 Saccharomyces cerevisiae，必要基因 CDC13 编码 telomeric 遗传上并且身体上与 Stn1p 和 Ten1p 交往的搁浅单人赛的 DNA 有约束力的蛋白质，并且为 telomere 结束保护和 telomere 长度控制被要求。Ten1 由参予 telomere 长度规定和染色体结束保护的分子的机制留下逃犯。在这个工作，我们用净化的 recombinant Cdc13p 和 Ten1p 在胶化过滤分析观察了 Cdc13p 和 Ten1p 的一个弱相互作用。Ten1p 本身展出一项弱 DNA 有约束力的活动，但是提高 telomeric TG1 鈥吗？Cdc13p 的 DNA 有约束力的能力。Cdc13p 是有 Ten1p 的 co-immunoprecipitated。在变异的 ten1-55 或 ten1-66 房间，在 Ten1p 和 Cdc13p 之间的损害相互作用与 telomeric DNA 导致长得多的 telomeres，以及 Cdc13p 的一个减少的协会。一致地， Ten1-55 和 Ten1-66 异种蛋白质没能刺激 telomeric 在 vitro 的 Cdc13p 的 DNA 有约束力的活动。这些结果建议 Ten1p 提高 telomeric Cdc13p 到的 DNA 有约束力的活动否定地调整 telomere 长度。

The role of NBS1 in DNA double strand break repair, telomere stability, and cell cycle checkpoint control

真核细胞的房间的染色体在由环境代理人和内长的新陈代谢的副产品的连续袭击下面。在 DNA 导致的损坏通常导致细胞的事件的串联， DNA 损坏反应。DNA 损坏反应的失败能由减少 DNA 修理的效率和忠实导致恶意的开发。NBS1 蛋白质是在对 DNA 损坏和 chromosomal 正直的维护的细胞的反应起一个关键作用的 MRE11/RAD50/NBS1 建筑群(MRN ) 的一个部件。在 NBS1 基因的变化为 Nijmegen 破裂症候群(NBS ) 负责，给予增加的倾向到恶意的开发的世袭混乱。从病人们在 DNA 双海滨裂缝的修理指向缺乏的 NBS 孤立的房间的 phenotypic 特征。这里，我们在 DNA 损坏反应考察 NBS1 的角色的当前的知识。强调在 DNA 双海滨修理，察觉到并且发信号的 DNA 损坏的调整，房间周期检查点控制和 telomere 稳定性的维护被放在 NBS1 的角色上。