Understanding TERT promoter mutations: a common path to immortality

Telomerase (TERT) activation is a fundamental step in tumorigenesis. By maintaining telomere length, telomerase relieves a main barrier on cellular lifespan, enabling limitless proliferation driven by oncogenes. The recently discovered, highly recurrent mutations in the promoter of TERT are found in over 50 cancer types, and are the most common mutation in many cancers. Transcriptional activation of TERT, via promoter mutation or other mechanisms, is the rate-limiting step in production of active telomerase. Although TERT is expressed in stem cells, it is naturally silenced upon differentiation. Thus, the presence of TERT promoter mutations may shed light on whether a particular tumor arose from a stem cell or more differentiated cell type. It is becoming clear that TERT mutations occur early during cellular transformation, and activate the TERT promoter by recruiting transcription factors that do not normally regulate TERT gene expression. This review highlights the fundamental and widespread role of TERT promoter mutations in tumorigenesis, including recent progress on their mechanism of transcriptional activation. These somatic promoter mutations, along with germline variation in the TERT locus also appear to have significant value as biomarkers of patient outcome. Understanding the precise molecular mechanism of TERT activation by promoter mutation and germline variation may inspire novel cancer cell-specific targeted therapies for a large number of cancer patients.Support was provided from a generous gift from the Dabbiere family(RJB,AM,JFC), the Hana Jabsheh Research Initiative (RJB,AM,JFC), and NIH grants NCI P50CA097257 (RJB,AM,JFC), P01CA118816-06 (RJB,AM,JFC), R01HG003008 (HTR), and R01CA163336 (JSS). Additional support was provided from the Sontag Foundation Distinguished Scientist Award (JSS), Fundação para a Ciência e Tecnologia SFRH/BD/88220/2012 (AXM), IF/00601/2012 (BMC), Programa Operacional Regional do Norte (ON.2—O Novo Norte) (BMC), Quadro de Referência Estratégico Nacional (BMC), and Fundo Europeu de Desenvolvimento Regional (BMC).info:eu-repo/semantics/publishedVersio

Adaptive Luenberger-Sliding Mode Controller Based Speed Estimation and Control of Sensorless Induction Motor

In the last decade, different techniques of induction motor control were widely used for low and high-performance applications. For high-performance drive systems, the field-oriented control (FOC) is more efficient when it integrates with advanced control techniques. The conventional field-oriented control uses a sensor for speed feedback to the controller. Convectional FOC is affected by the coupling effect between torque and flux component and sensitive for the unknown parameter variation. Sensor feedback error may affect the reliability and increase cost and controller design complexity. The proposed ALSMC control approach uses advanced speed controllers, indirect field-oriented control (IFOC) with sliding mode control (SMC) and adaptive Luenberger state observer to achieve high dynamic performance. The simulation throughout the documentation was implemented by using MATLAB/Simulink software. In this thesis, the speed, torque, and stator current responses with MRAC based PI controller and Adaptive Luenberger Sliding Mode Control (ALSMC) controller were compared and found that the proposed ALSMC based controller showed improved dynamic performance and better stabilization for load torque variation. The proposed adaptive Luenberger sliding mode control is better in overshot which is 0.426% and that of PI controller is 4.348%, and it has better settling time which is 0.5seconds and that of PI is 0.98 seconds

CUT-PCR: CRISPR-mediated, ultrasensitive detection of target DNA using PCR

Circulating tumor DNA (ctDNA) has emerged as a tumor-specific biomarker for the early detection of various cancers. To date, several techniques have been devised to enrich the extremely small amounts of ctDNA present in plasma, but they are still insufficient for cancer diagnosis, especially at the early stage. Here, we developed a novel method, CUT (CRISPR-mediated, Ultrasensitive detection of Target DNA)-PCR, which uses CRISPR endonucleases to enrich and detect the extremely small amounts of tumor DNA fragments among the much more abundant wild-type DNA fragments by specifically eliminating the wild-type sequences. We computed that by using various orthologonal CRISPR endonucleases such as SpCas9 and FnCpf1, the CUT-PCR method would be applicable to 80% of known cancer-linked substitution mutations registered in the COSMIC database. We further verified that CUT-PCR together with targeted deep sequencing enables detection of a broad range of oncogenes with high sensitivity (<0.01%) and accuracy, which is superior to conventional targeted deep sequencing. In the end, we successfully applied CUT-PCR to detect sequences with oncogenic mutations in the ctDNA of colorectal cancer patients' blood, suggesting that our technique could be adopted for diagnosing various types of cancer at early stages

A Head Above the Rest: Use of Prosected Specimens Increases Practical Exam Performance for Head and Neck Anatomy

INTRODUCTION/OBJECTIVE: Kansas City University has historically used student-led dissections for anatomy education in the first year medical curriculum. In academic year (AY) 2019-20, prosected cadaver specimens were incorporated in the ‘head and neck’ component of the Neuroendocrine (NE) course. Literature addressing the use of prosected cadavers yields identical student outcomes when assessing larger structures like the extremities as compared to student-led dissections, however, a single report indicates that in areas with exceedingly small and/or complex dissections, such as the foot, using prosected specimens improves student outcomes. The aim of this study was to evaluate the impact of prosected specimens on student performance on laboratory practical exams specific to head and neck content. MATERIALS/METHODS: In AY2019-20, prosected cadavers were prepared by members of the Anatomy department prior to the start of the NE course. The number of anatomy lab sessions and structure list remained identical between the AY2018-19 and AY2019-20 cohorts. A 50-point laboratory practical exam was administered to each cohort and common assessment items (n=21) were included. Retrospective data sets were obtained for student-led dissection outcomes (SDO, n=278) from AY2018-19, and prosected specimen outcomes (PSO, n=280) from AY19-20. Common assessment items among the two cohorts were tabulated and bimodal statistics were applied including the Mann-Whitney U test, using SPSS. RESULTS: Student outcomes of mean scores on all common tags was greater in the PSO cohort (0.83 +/- 0.005) as compared to SDO performance (0.760 +/- 0.005) (P CONCLUSION: We completed a retrospective, region-specific analysis of assessment outcomes in head and neck laboratory practical exams. Students performed better within the PSO cohort overall, as well as on ten items specific to deep anatomical structures. This study demonstrates the impact of using prosected specimens in teaching head and neck anatomy. SIGNIFICANCE/IMPLICATION: Structures of the head and neck are very delicate and pose a perceived barrier to student success. Using prosected specimens resulted in increased exam performance overall, as well as on assessment items specific to more deeply positioned structures. In contrast, outcomes of student-dissected assessment items were increased when evaluating superficial structures. The improved performance of practical assessment items specific to prosected and deep, versus dissected and superficial, suggests that structure accessibility impacts student outcomes. This indicates that students are better able to use prosection to more successfully locate, identify, and assess deeply positioned structures

Battle of the Sections: Student Outcomes and Course Feedback Support Combined Prosection and Dissection Laboratory Formats to Maximize Student Success

Gross anatomy laboratories frequently utilize dissection or prosection formats within medical curricula. Practical examination scores are consistent across the formats, yet these examinations assessed larger anatomical structures. In contrast, a single report noted improved scores when prosection was used in the hand and foot regions, areas that are more difficult to dissect. The incorporation of prosected donors within Head and Neck laboratories provided an opportunity to further characterize the impact of prosection in a structurally complex area. Retrospective analysis of 21 Head and Neck practical examination questions was completed to compare scores among cohorts that utilized dissection exclusively or incorporated prosection. Mean scores of practical examination questions were significantly higher in the prosection cohort (84.27% ± 12.69) as compared with the dissection cohort (75.59% ± 12.27) (p \u3c 0.001). Of the 12 questions that performed better in the prosection cohort (88.42% ± 8.21), 10 items mapped to deeper anatomical regions. By comparison, eight of nine questions in the dissection cohort outperformed (88.44% ± 3.34) the prosection cohort (71.74% ± 18.11), and mapped to anatomically superficial regions. Despite the mean score increase with positional location of the questions, this effect was not statically significant across cohorts (p = 1.000), suggesting that structure accessibility in anatomically complex regions impacts performance. Student feedback cited structure preservation (71.5%) and time savings (55.8%) as advantages to prosection; however, dissection was the perceived superior and preferred laboratory format (88.6%). These data support combined prosection and dissection formats for improving student recognition of deeply positioned structures and maximizing student success

Telomerase promoter mutations in cancer: an emerging molecular biomarker?

João Vinagre, Vasco Pinto and Ricardo Celestino contributed equally to the manuscript.Cell immortalization has been considered for a long time as a classic hallmark of cancer cells. Besides telomerase reactivation, such immortalization could be due to telomere maintenance through the “alternative mechanism of telomere lengthening” (ALT) but the mechanisms underlying both forms of reactivation remained elusive. Mutations in the coding region of telomerase gene are very rare in the cancer setting, despite being associated with some degenerative diseases. Recently, mutations in telomerase (TERT) gene promoter were found in sporadic and familial melanoma and subsequently in several cancer models, notably in gliomas, thyroid cancer and bladder cancer. The importance of these findings has been reinforced by the association of TERT mutations in some cancer types with tumour aggressiveness and patient survival. In the first part of this review, we summarize the data on the biology of telomeres and telomerase, available methodological approaches and non-neoplastic diseases associated with telomere dysfunction. In the second part, we review the information on telomerase expression and genetic alterations in the most relevant types of cancer (skin, thyroid, bladder and central nervous system) on record, and discuss the value of telomerase as a new biomarker with impact on the prognosis and survival of the patients and as a putative therapeutic target

Mechanisms of human telomerase reverse transcriptase (hTERT) regulation: clinical impacts in cancer

Background Limitless self-renewal is one of the hallmarks of cancer and is attained by telomere maintenance, essentially through telomerase (hTERT) activation. Transcriptional regulation of hTERT is believed to play a major role in telomerase activation in human cancers. Main body The dominant interest in telomerase results from its role in cancer. The role of telomeres and telomere maintenance mechanisms is well established as a major driving force in generating chromosomal and genomic instability. Cancer cells have acquired the ability to overcome their fate of senescence via telomere length maintenance mechanisms, mainly by telomerase activation. hTERT expression is up-regulated in tumors via multiple genetic and epigenetic mechanisms including hTERT amplifications, hTERT structural variants, hTERT promoter mutations and epigenetic modifications through hTERT promoter methylation. Genetic (hTERT promoter mutations) and epigenetic (hTERT promoter methylation and miRNAs) events were shown to have clinical implications in cancers that depend on hTERT activation. Knowing that telomeres are crucial for cellular self-renewal, the mechanisms responsible for telomere maintenance have a crucial role in cancer diseases and might be important oncological biomarkers. Thus, rather than quantifying TERT expression and its correlation with telomerase activation, the discovery and the assessment of the mechanisms responsible for TERT upregulation offers important information that may be used for diagnosis, prognosis, and treatment monitoring in oncology. Furthermore, a better understanding of these mechanisms may promote their translation into effective targeted cancer therapies. Conclusion Herein, we reviewed the underlying mechanisms of hTERT regulation, their role in oncogenesis, and the potential clinical applications in telomerase-dependent cancers.info:eu-repo/semantics/publishedVersio

Exaggerated CpH methylation in the autism-affected brain

BACKGROUND: The etiology of autism, a complex, heritable, neurodevelopmental disorder, remains largely unexplained. Given the unexplained risk and recent evidence supporting a role for epigenetic mechanisms in the development of autism, we explored the role of CpG and CpH (H = A, C, or T) methylation within the autism-affected cortical brain tissue. METHODS: Reduced representation bisulfite sequencing (RRBS) was completed, and analysis was carried out in 63 post-mortem cortical brain samples (Brodmann area 19) from 29 autism-affected and 34 control individuals. Analyses to identify single sites that were differentially methylated and to identify any global methylation alterations at either CpG or CpH sites throughout the genome were carried out. RESULTS: We report that while no individual site or region of methylation was significantly associated with autism after multi-test correction, methylated CpH dinucleotides were markedly enriched in autism-affected brains (~2-fold enrichment at p < 0.05 cutoff, p = 0.002). CONCLUSIONS: These results further implicate epigenetic alterations in pathobiological mechanisms that underlie autism. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13229-017-0119-y) contains supplementary material, which is available to authorized users

Disruption of DNA methylation-dependent long gene repression in Rett syndrome

Disruption of the MECP2 gene leads to Rett syndrome (RTT), a severe neurological disorder with features of autism1. MECP2 encodes a methyl-DNA-binding protein2 that has been proposed to function as a transcriptional repressor, but despite numerous studies examining neuronal gene expression in Mecp2 mutants, no clear model has emerged for how MeCP2 regulates transcription3–9. Here we identify a genome-wide length-dependent increase in gene expression in MeCP2 mutant mouse models and human RTT brains. We present evidence that MeCP2 represses gene expression by binding to methylated CA sites within long genes, and that in neurons lacking MeCP2, decreasing the expression of long genes attenuates RTT-associated cellular deficits. In addition, we find that long genes as a population are enriched for neuronal functions and selectively expressed in the brain. These findings suggest that mutations in MeCP2 may cause neurological dysfunction by specifically disrupting long gene expression in the brain