Strongly associated with tobacco use, heavy alcohol consumption, and with high-risk human papillomavirus (HPV) infection, head and neck squamous cell carcinoma (HNSCC) is a frequently lethal, ...heterogeneous disease whose pathogenesis is a multistep and multifactorial process involving genetic and epigenetic events. The majority of HNSCC patients present with locoregional advanced stage disease and are treated with combined modality strategies that can markedly impair quality of life and elicit unpredictable results. A large fraction of those who undergo locoregional treatment and achieve a complete response later develop locoregional recurrences or second field tumors. Biomarkers that are thus able to stratify risk and enable clinicians to tailor treatment plans and to personalize post-therapeutic surveillance strategies are highly desirable. To date, only HPV status is considered a reliable independent predictor of treatment response and survival in patients with HNSCC arising from the oropharyngeal site. Recent studies suggest that telomere attrition, which may be an early event in human carcinogenesis, and telomerase activation, which is detected in up to 90 % of malignancies, could be potential markers of cancer risk and disease outcome. This review examines the current state of knowledge on and discusses the implications linked to telomere dysfunction and telomerase activation in the development and clinical outcome of HNSCC.
Besides its canonical role in stabilizing telomeres, telomerase reverse transcriptase (TERT) may promote tumor growth/progression through extra-telomeric functions. Our previous in vitro studies ...demonstrated that short-term TERT inhibition by BIBR1532 (BIBR), an inhibitor of TERT catalytic activity, negatively impacts cell proliferation and viability via telomeres’ length-independent mechanism. Here we evaluate the anti-proliferative and pro-apoptotic effects of short-term telomerase inhibition in vivo in wild-type (wt) and tert mutant (terthu3430/hu3430; tert−/−) zebrafish embryos, and in malignant human B cells xenografted in casper zebrafish embryos. Short-term Tert inhibition by BIBR in wt embryos reduced cell proliferation, induced an accumulation of cells in S-phase and ultimately led to apoptosis associated with the activation of DNA damage response; all these effects were unrelated to telomere shortening/dysfunction. BIBR treatment showed no effects in tert−/− embryos. Xenografted untreated malignant B cells proliferated in zebrafish embryos, while BIBR pretreated cells constantly decreased and were significantly less than those in the controls from 24 to up to 72 h after xenotransplantation. Additionally, xenografted tumor cells, treated with BIBR prior- or post-transplantation, displayed a significant higher apoptotic rate compared to untreated control cells. In conclusion, our data demonstrate that short-term telomerase inhibition impairs proliferation and viability in vivo and in human malignant B cells xenografted in zebrafish, thus supporting therapeutic applications of TERT inhibitors in human malignancies.
Purpose
To evaluate the prevalence of two recurrent somatic mutations (−124 C>T and −146 C>T) within the promoter of the gene encoding telomerase reverse transcriptase (
TERT
) as well as their ...relationship with
TERT
level, telomeres length, and outcome in patients with head and neck squamous cell carcinomas (HNSCCs).
Methods
We evaluate the prevalence of
TERT
promoter mutations,
TERT
levels, and telomere length in paired cancer tissue and adjacent mucosa (AM) in a series of HNSCCs.
Results
Cancer tissue and AM specimens from 105 patients were analyzed
.
Telomere length and
TERT
mRNA levels were estimated using real-time polymerase chain reaction.
TERT
promoter mutations were assessed using Sanger sequencing. Out of 105 cases, 101 were considered suitable for the analysis.
TERT
promoter harbored mutations in 12 tumors (11.9%), with −124 C>T and −146 C>T accounting for 83.3% and 16.7% of the alterations, respectively. No mutations were detected in AM samples. The prevalence of
TERT
promoter mutations was significantly higher in oral cavity SCCs (10 out of 27 tumors; 37%), and telomere length in AM was shorter in patients with tumors carrying
TERT
promoter mutations than in patients with unmutated
TERT
promoter cancers (
p
= 0.023).
TERT
levels in tumor did not significantly differ according to the mutational status of
TERT
promoter. No significant association was found between
TERT
promoter status and overall survival.
Conclusion
TERT
promoter mutations are most likely a late event in tumor development, occurring in a context of critically short telomeres, mostly in patients with oral cavity SCC.
TERT
levels, but not
TERT
promoter mutational status impact clinical outcome.
In-depth characterization of recurrent glioblastoma (rGBM) might contribute to a better understanding of the mechanisms behind tumor progression and enable rGBM treatment with targeted drugs.
In this ...study, GBM samples were collected at diagnosis and recurrence from adult patients treated with Stupp protocol. Expression of mismatch repair (MMR) proteins was evaluated by IHC, followed by whole exome sequencing (WES) of tumor samples showing loss of MSH6 reactivity. Established genetic, epigenetic, and immunologic markers were assessed by standard methods and correlated with loss of MMR proteins and patient survival.
Expression of MMR proteins was partially or completely lost in 25.9% rGBM samples. Specifically, 12 samples showed partial or total MSH6 expression reduction. Conversely, 96.4% of GBM samples at diagnosis expressed MMR markers. WES disclosed lack of variants in MMR genes in primary samples, whereas two MSH6-negative rGBM samples shared a c.3438+1G>A* splicing
variant with a potential loss of function effect. MSH6-negative rGBM specimens had high tumor mutational burden (TMB), but no microsatellite instability. In contrast, GBM samples with partial loss of MMR proteins disclosed low TMB. MMR-deficient rGBM showed significant telomere shortening and MGMT methylation and are characterized by highly heterogeneous MHC class I expression.
Multilevel profiling of MMR-deficient rGBM uncovered hypermutated genotype uncoupled from enriched expression of immune-related markers. Assessment of MHC class I expression and TMB should be included in protocols aiming to identify rGBM patients potentially eligible for treatment with drugs targeting immune-checkpoint inhibitors.
Summary From the use of antiretroviral therapy to prevent mother-to-child transmission to the possibility of HIV cure hinted at by the Mississippi baby experience, paediatric HIV infection has been ...pivotal to our understanding of HIV pathogenesis and management. Daily medication and indefinite antiretroviral therapy is recommended for children infected with HIV. Maintenance of life-long adherence is difficult and the incidence of triple-class virological failure after initiation of antiretroviral therapy increases with time. This challenge shows the urgent need to define novel strategies to provide long-term viral suppression that will allow safe interruption of antiretroviral therapy without viral rebound and any associated complications. HIV-infected babies treated within a few days of birth have a unique combination of a very small pool of integrated viruses, a very high proportion of relatively HIV resistant naive T cells, and an unparalleled capacity to regenerate an immune repertoire. These features make this group the optimum model population to investigate the potential efficacy of immune-based therapies. If successful, these investigations could change the way we manage HIV infection.
Purpose
To investigate whether the plasma levels of cell-free RNA (cfRNA) and telomere-specific reverse transcriptase mRNA (hTERT) are associated with tumor response in rectal cancer patients who ...received preoperative chemoradiotherapy (pCRT).
Methods
Patients who underwent pCRT for rectal cancer and for whom baseline and paired post-pCRT blood samples were available were studied. On the basis of tumor regression score, patients were classified as having response or having no response. Clinical variables and plasma levels of cfRNA and hTERT before and after the pCRT were evaluated. The association between each predictor and tumor response was assessed by univariate and multivariate analyses.
Results
Of 98 eligible patients, 45 were determined to respond to therapy, and 53 did not respond to therapy. In univariate analysis, gender (
P
= 0.040), baseline levels of cfRNA (
P
= 0.026), post-pCRT levels of both hTERT and cfRNA (
P
< 0.0001 and
P
= 0.001, respectively), and the difference between the post- and pre-pCRT levels of both hTERT and cfRNA (
P
= 0.009 and
P
= 0.001, respectively) were found to be significant predictors of tumor response. In multivariate analysis, using variables that were available before pCRT, cfRNA levels and gender independently predicted the tumor response, while in multivariate analysis, which used all of the variables available before the surgical procedure, the post-pCRT levels of cfRNA and the difference between the post- and pre-pCRT levels of cfRNA independently predicted tumor response.
Conclusions
Plasma levels of cfRNA and hTERT are promising markers of tumor response to pCRT for rectal cancer.
The size of the latent HIV reservoir is associated with the timing of therapeutic interventions and overall health of the immune system. Here, we demonstrate that T cell phenotypic signatures ...associate with viral reservoir size in a cohort of HIV vertically infected children and young adults under durable viral control, and who initiated anti-retroviral therapy (ART) <2 years old. Flow cytometry was used to measure expression of immune activation (IA), immune checkpoint (ICP) markers, and intracellular cytokine production after stimulation with GAG peptides in CD4 and CD8 T cells from cross-sectional peripheral blood samples. We also evaluated the expression of 96 genes in sort-purified total CD4 and CD8 T cells along with HIV-specific CD4 and CD8 T cells using a multiplexed RT-PCR approach. As a measure of HIV reservoir, total HIV-DNA quantification by real-time PCR was performed. Poisson regression modeling for predicting reservoir size using phenotypic markers revealed a signature that featured frequencies of PD-1+CD4 T cells, TIGIT+CD4 T cells and HIV-specific (CD40L+) CD4 T cells as important predictors and it also shows that time of ART initiation strongly affects their association with HIV-DNA. Further, gene expression analysis showed that the frequencies of PD-1+CD4 T cells associated with a CD4 T cell molecular profile skewed toward an exhausted Th1 profile. Our data provide a link between immune checkpoint molecules and HIV persistence in a pediatric cohort as has been demonstrated in adults. Frequencies of PD-1+ and TIGIT+CD4 T cells along with the frequency of HIV-specific CD4 T cells could be associated with the mechanism of viral persistence and may provide insight into potential targets for therapeutic intervention.
Introduction
HIV infection causes pathological changes in the natural killer (NK) cell compartment that can be only partially restored by antiretroviral therapy (ART). We investigated NK cells ...phenotype and function in children with perinatally acquired HIV (PHIV) and long‐term viral control (five years) due to effective ART in a multicentre cross‐sectional European study (CARMA, EPIICAL consortium). The impact of age at ART start and viral reservoir was also evaluated.
Methods
Peripheral blood mononuclear cells (PBMCs) from 40 PHIV who started ART within two years of life (early treated patients (ET), ≤6 months; late treated patients (LT), > 6 months), with at least five years of HIV‐1 suppression (<40 HIV copies/mL), were collected between November 2017 and August 2018. NK phenotype and function were analysed by flow cytometry and transcriptional profile of PBMCs by RNA‐Seq. HIV‐1 DNA was measured by real‐time polymerase chain reaction (Data were analysed by Spearman correlation plots and multivariable Poisson regression model (adjusted for baseline %CD4 and RNA HIV viral load and for age at ART start as an interaction term, either ET or LT) to explore the association between NK cell parameters and HIV reservoir modulated by age at ART start.
Results
A significantly higher frequency of CD56neg NK cells was found in LT compared with ET. We further found in LT a positive correlation of CD56neg NK cells with HIV‐1 DNA. LT also displayed increased expression of the NKG2D and NKp46 activating receptors and perforin compared with ET. Moreover, CD107a+ and IFN‐γ+ frequencies in non‐stimulated NK were associated with HIV‐1 DNA in LT patients. Finally, RNA‐Seq analysis showed in LT an up‐regulation of genes related to NK‐activating pathways and susceptibility to apoptosis compared with ET.
Conclusions
We show that early initiation of ART during infancy preserves the NK compartment and is associated with lower HIV‐1 reservoir. Such condition persists over adolescence due to long‐term viral control achieved through effective ART.
Telomeres,telomerase and colorectal cancer Bertorelle, Roberta; Rampazzo, Enrica; Pucciarelli, Salvatore ...
World journal of gastroenterology,
02/2014, Letnik:
20, Številka:
8
Journal Article
Odprti dostop
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.
The challenge of immune senescence has never been addressed in elderly cancer patients. This study compares the thymic output and peripheral blood telomere length in ≥70year old cancer patients.
...Fifty-two elderly cancer patients and 39 age-matched controls without personal history of cancer were enrolled. All patients underwent a Comprehensive Geriatric Assessment (CGA), from which a multidimensional prognostic index (MPI) score was calculated. Peripheral blood samples were studied for naïve and recent thymic emigrant (RTE) CD4+ and CD8+ cells by flow cytometry. T-cell receptor rearrangement excision circle (TREC) levels, telomere length and telomerase activity in peripheral blood cells were quantified by real-time PCR.
The percentages of CD8+ naïve and CD8+ RTE cells and TREC levels were significantly lower in cancer patients than in controls (p=0.003, p=0.004, p=0.031, respectively). Telomere lengths in peripheral blood cells were significantly shorter in cancer patients than in controls (p=0.046) and did not correlate with age in patients, whereas it did in controls (r=−0.354, p=0.031). Short telomere (≤median)/low TREC (≤median) profile was associated with higher risk of cancer (OR=3.68 95% CI 1.22–11.11; p=0.021). Neither unfitness on CGA nor MPI score were significantly related to thymic output or telomere length in either group.
Immune senescence is significantly worse in elderly cancer patients than in age-matched controls. The low thymic output and the shorter telomeres in peripheral blood cells of cancer patients may reflect a pre-existing condition which facilitates the onset of malignancies in elderly people.
•Telomere lengths in peripheral blood cells are shorter in elderly cancer patients than in age-matched controls.•Thymic output (TREC) is lower in cancer patients than in age-matched controls.•“Short telomere/low TREC” profile is associated with higher risk of cancer.
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