Reactivation of telomerase in cancer

hTERT rs2735940 polymorphism influences lung cancer risk and overall survival in lung cancer patients undergoing platinum-based doublet chemotherapy

BACKGROUND

The hTERT gene is an essential part of the telomerase enzyme, preserving telomere length and encouraging cellular immortality. The study aimed to investigate whether the TERT gene SNP was associated with an increased risk of lung cancer in the North Indian population.

RESEARCH DESIGN AND METHODS

387 lung cancer patients undergoing platinum-based chemotherapy and 384 healthy controls were genotyped for the TERT variant rs2735940 (T>C) using PCR-RFLP. The study aimed to determine the significant association between the TERT genetic variant and lung cancer risk.

RESULTS

Patients carrying homozygous mutant genotype (CC) for rs2735940 showed a significant association (0 R = 2.4, p = 0.03). Furthermore, in dominant model, the combination genotype (TC+CC) showed an increased risk of lung cancer susceptibility with an AOR of 1.67 (p = 0.0016). For TERT rs2735940, individuals with SCLC carrying the mutant genotype (CC) were significantly more likely to develop lung cancer (p = 0.0004). Our results also showed that lung cancer patients carrying the TERT rs2735940 genetic variant who received a combination of docetaxel and cisplatin/carboplatin had better prognosis as compared to alternative chemotherapy regimens.

CONCLUSION

Our study associates' chemotherapy toxicities in North Indian lung cancer patients and the TERT polymorphism rs2735940, delivering insights for improving biomarker development and individualized treatment.

Managing telomerase and telomere dysfunction in acral melanoma

Acral Lentiginous Melanoma is a rare and aggressive subtype of melanoma that commonly affects the palms, soles, and nail beds. It is more prevalent in individuals with darker skin tones, including Asian, African, and Hispanic populations. Unlike cutaneous melanomas, acral melanoma is not associated with UV exposure and has a distinct genetic and molecular profile, underscoring the need for tailored research and treatment strategies. Standard treatments, such as surgery, chemotherapy, immunotherapy, and targeted therapies, have shown limited success for this melanoma subtype, highlighting the urgency of developing more effective interventions. Telomerase is an enzyme that extends telomeres and is a key target in acral melanoma which exhibits' high telomerase activity, driven by mutations in the telomerase reverse transcriptase TERT promoter, which contributes to uncontrolled tumor cell proliferation, cancer cell immortality, and resistance to conventional therapies. Therefore, targeting telomerase presents a promising therapeutic avenue for acral melanoma patients who do not respond well to current treatments. Several approaches for targeting telomerase deregulation have been developed, and their potential for the management of acral melanoma is discussed in this review. Specifically, the promise of telomerase-targeted therapies for acral melanoma is emphasized and explores how these strategies could improve outcomes for patients with this challenging skin cancer. By focusing on the role of telomerase in tumorigenesis and treatment resistance, telomerase-targeted strategies hold potential as a foundational component of therapies for acral melanoma, complementing existing approaches.

Harnessing Immune Rejuvenation: Advances in Overcoming T Cell Senescence and Exhaustion in Cancer Immunotherapy

Immunotherapy has transformed the landscape of cancer treatment, with T cell-based strategies at the forefront of this revolution. However, the durability of these responses is frequently undermined by two intertwined phenomena: T cell exhaustion and senescence. While exhaustion is driven by chronic antigen exposure in the immunosuppressive tumor microenvironment, leading to a reversible state of diminished functionality, senescence reflects a more permanent, age- or stress-induced arrest in cellular proliferation and effector capacity. Together, these processes represent formidable barriers to sustained anti-tumor immunity. In this review, we dissect the molecular underpinnings of T cell exhaustion and senescence, revealing how these dysfunctions synergistically contribute to immune evasion and resistance across a range of solid tumors. We explore cutting-edge therapeutic approaches aimed at rewiring the exhausted and senescent T cell phenotypes. These include advances in immune checkpoint blockade, the engineering of "armored" CAR-T cells, senolytic therapies that selectively eliminate senescent cells, and novel interventions that reinvigorate the immune system's capacity for tumor eradication. By spotlighting emerging strategies that target both exhaustion and senescence, we provide a forward-looking perspective on the potential to harness immune rejuvenation. This comprehensive review outlines the next frontier in cancer immunotherapy: unlocking durable responses by overcoming the immune system's intrinsic aging and exhaustion, ultimately paving the way for transformative therapeutic breakthroughs.

Novel Genetic Risk Variants Associated with Oral Tongue Squamous Cell Carcinoma

PURPOSE

Limited data from genome-wide association studies (GWAS) focusing on oral tongue squamous cell carcinoma (OTSCC) are available. The present study was conducted to explore genetic associations for OTSCC.

METHODS

A GWAS on 376 cases of OTSCC was conducted using the FinnGen Data Freeze-12 dataset. The case-cohort included 205 males and 171 females. Cases with malignancies involving the base of the tongue or lingual tonsil were excluded from the case-cohort. Individuals with no recorded history of malignancy were used as controls (n = 407,067). A Phenome-wide association study (PheWAS) was performed for the lead variants to assess their co-associations with other cancers.

RESULTS

GWAS analysis identified three genome-wide significant loci associated with OTSCC (p < 5 × 10-8), located at 5p15.33 (rs27067 near gene LINC01511), 10q24 (rs1007771191 near RPS3AP36), and 20p12.3 (rs1438070080 near PLCB1), respectively. PheWAS showed associations of rs27067 mainly with prostate cancer (OR = 1.06, p = 5.41 × 10-7), and seborrheic keratosis (OR = 1.11, p = 1.51 × 10-11). A co-directional effect with melanoma was also observed (OR = 0.93, p = 6.24 × 10-5).

CONCLUSION

The GWAS detected two novel genetic associations with OTSCC. Further research is needed to identify the genes at these loci that contribute to the molecular pathogenesis of OTSCC.

Beyond Telomeres: Unveiling the Extratelomeric Functions of TERT in B-Cell Malignancies

The reactivation of telomerase enables cancer cells to maintain the telomere length, bypassing replicative senescence and achieving cellular immortality. In addition to its canonical role in telomere maintenance, accumulating evidence highlights telomere-length-independent functions of TERT, the catalytic subunit of telomerase. These extratelomeric functions involve the regulation of signaling pathways and transcriptional networks, creating feed-forward loops that promote cancer cell proliferation, resistance to apoptosis, and disease progression. This review explores the complex mechanisms by which TERT modulates key signaling pathways, such as NF-κB, AKT, and MYC, highlighting its role in driving autonomous cancer cell growth and resistance to therapy in B-cell malignancies. Furthermore, we discuss the therapeutic potential of targeting TERT's extratelomeric functions. Unlike telomere-directed approaches, which may require prolonged treatment to achieve effective telomere erosion, inhibiting TERT's extratelomeric functions offers the prospect of rapid tumor-specific effects. This strategy could complement existing chemotherapeutic regimens, providing an innovative and effective approach to managing B-cell malignancies.

Telomere length and telomerase reverse transcriptase gene polymorphism as potential markers of complete chimerism and GvHD development after allogeneic haematopoietic stem cell transplantation

INTRODUCTION

Telomerase reverse transcriptase (TERT) is a catalytic subunit of telomerase that maintains genome stability by maintaining telomere length (TL). The massive proliferation of donor cells in the recipient's body for engraftment results in accelerated telomere shortening. Genetic variability within the TERT gene affects telomerase activity, and was shown to influence of haematopoietic stem cell transplantation (HSCT) outcome. In the present study, we aimed to analyse the effect of recipient and donor TL and TERT single nucleotide polymorphism (SNP) on the occurrence of post-HSCT complications.

METHODS

Our study included 120 recipient-donor pairs. TERT promoter (TERTp) SNP (rs2853669) SNP variant was detected with the use of the LightSNiP typing assay employing real-time polymerase chain reaction (PCR) amplifications. Telomere length measurements were performed using qPCR test kits (ScienCell's Absolute Human Telomere Length Quantification qPCR Assay Kit [AHTLQ], Carlsbad, CA, USA).

RESULTS

The presence of TERTp rs2853669 T allele in the recipient was associated with a higher risk for acute graft-versus-host-disease (aGvHD) manifestation (p = 0.046) and a significantly shorter aGvHD-free survival (p = 0.041). The latter association was further confirmed in a Cox proportional hazards model (p = 0.043). However, no statistically significant association between telomere length and post-transplant complications was observed. Furthermore, we found that shorter TL characterized donors of patients with late complete chimerism at 180 day after HSCT (p = 0.011).

CONCLUSION

Our results suggest that recipient allele TERTp rs2853669 T is a marker of unfavourable outcome in the context of aGvHD. Shorter TL in donors could be associated with later achievement of complete chimerism.

From infection to immortality: The role of HPV and telomerase in head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) represent a heterogeneous group of malignancies with multifactorial aetiologies. High-risk human papillomavirus (hrHPV) infections, particularly HPV16, and the dysregulation of telomerase activity, specifically through its catalytic subunit, telomerase reverse transcriptase (TERT) are among the key contributors to HNSCC development and progression. HPV promotes oncogenesis via the E6 and E7 oncoproteins, which inactivate tumour suppressors TP53 and RB1, leading to unchecked cellular proliferation. Concurrently, telomerase activation plays a critical role in HNSCC by maintaining telomere length, thus enabling cellular immortality, and facilitating tumour development and progression. The interplay between HPV and telomerase is significant; HPV oncoprotein E6 enhances telomerase activity through multiple regulatory mechanisms, including upregulating TERT expression. Beyond telomere maintenance, TERT influences signalling pathways, cellular metabolism, and the tumour microenvironment, contributing to aggressive tumour behaviour and poor prognosis. This review integrates the roles of HPV and telomerase in HNSCC, focusing on their molecular mechanisms and interactions that drive carcinogenesis and influence disease progression. Understanding the synergistic effects of HPV and TERT in HNSCC may be crucial for risk stratification, prognostic assessment, and the development of novel therapeutic strategies targeting these specific molecular pathways.

Targeted therapies for myelodysplastic syndromes/neoplasms (MDS): current landscape and future directions

INTRODUCTION

Myelodysplastic syndromes/neoplasms (MDS) are a heterogeneous group of hematologic malignancies that are stratified into high-risk (HR-MDS) and low-risk (LR-MDS) categories. Until recently, LR-MDS has been typically managed by supportive measures and erythropoiesis-stimulating agents (ESAs); whereas management of HR-MDS typically included hypomethylating agents and allogeneic hematopoietic stem cell transplant. However, the limited rates and durations of response observed with these interventions prompted the search for targeted therapies to improve the outcomes among patients with MDS.

AREAS COVERED

Here, we review the current landscape of targeted therapies in MDS. These include pyruvate kinase and hypoxia-inducible factor (HIF) activators; TGF-beta, telomerase, BCL2 and isocitrate dehydrogenase (IDH) inhibitors; as well as novel approaches targeting inflammation, pyroptosis, immune evasion, and RNA splicing machinery.

EXPERT OPINION

This review highlights the progress and challenges in MDS treatment. Despite some promising results, many therapies remain in early development or have faced setbacks, emphasizing the need for a more comprehensive understanding of the disease's pathobiology. Continued research into targeted therapies, homogenous clinical trial designs, as well as increased incorporation of molecular prognostic tools and artificial intelligence into trial design are essential for developing effective treatments for MDS and improving patient outcomes.

Iron-(Fe3+)-Dependent Reactivation of Telomerase Drives Colorectal Cancers

Over-consumption of iron-rich red meat and hereditary or genetic iron overload are associated with an increased risk of colorectal carcinogenesis, yet the mechanistic basis of how metal-mediated signaling leads to oncogenesis remains enigmatic. Using fresh colorectal cancer samples we identify Pirin, an iron sensor, that overcomes a rate-limiting step in oncogenesis, by reactivating the dormant human telomerase reverse transcriptase (hTERT) subunit of the telomerase holoenzyme in an iron-(Fe3+)-dependent manner and thereby drives colorectal cancers. Chemical genetic screens combined with isothermal dose-response fingerprinting and mass spectrometry identified a small molecule SP2509 that specifically inhibits Pirin-mediated hTERT reactivation in colorectal cancers by competing with iron-(Fe3+) binding. Our findings, first to document how metal ions reactivate telomerase, provide a molecular mechanism for the well-known association between red meat and increased incidence of colorectal cancers. Small molecules like SP2509 represent a novel modality to target telomerase that acts as a driver of 90% of human cancers and is yet to be targeted in clinic. Significance: We show how iron-(Fe3+) in collusion with genetic factors reactivates telomerase, providing a molecular mechanism for the association between iron overload and increased incidence of colorectal cancers. Although no enzymatic inhibitors of telomerase have entered the clinic, we identify SP2509, a small molecule that targets telomerase reactivation and function in colorectal cancers.

CRL4DCAF4 E3 ligase-mediated degradation of MEN1 transcriptionally reactivates hTERT to sustain immortalization in colorectal cancer cells

Telomerase reactivation is implicated in approximately 85% of human cancers, yet its underlying mechanism remains elusive. In this study, we elucidate that the cullin-RING ubiquitin ligase 4 (CRL4) complex drives the reactivation of human telomerase reverse transcriptase (hTERT) in colorectal cancer (CRC) by degrading the tumor suppressor, menin 1 (MEN1). Our data show that, in noncancerous intestinal epithelial cells, the transcription factor specificity protein 1 (Sp1) recruits both the histone acetyltransferase p300 and MEN1 to suppress hTERT expression, thus maintaining telomere shortness post-cell division. Inflammation-induced microenvironments trigger an activation of the CRL4DCAF4 E3 ligase, leading to MEN1 ubiquitination and degradation in CRC cells. This process nullifies MEN1's inhibitory action, reactivates hTERT expression at the transcriptional level, interrupts telomere shortening and spurs uncontrolled cellular proliferation. Notably, MEN1 overexpression in CRC cells partially counteracts these oncogenic phenotypes. NSC1517, an inhibitor of the CRL4DCAF4 complex identified through high-throughput screening from a plant-derived chemical pool, hinders MEN1 degradation, attenuates hTERT expression and suppresses tumor growth in mouse xenograft models. Collectively, our research elucidates the transcriptional mechanism driving hTERT reactivation in CRC. Targeting the CRL4DCAF4 E3 ligase emerges as a promising strategy to counteract cancer cell immortalization and curb tumor progression.

Targeting hTERT Promoter G-Quadruplex DNA Structures with Small-Molecule Ligand to Downregulate hTERT Expression for Triple-Negative Breast Cancer Therapy

Human telomerase reverse transcriptase (hTERT) may have noncanonical functions in transcriptional regulation and metabolic reprogramming in cancer cells, but it is a challenging target. We thus developed small-molecule ligands targeting hTERT promoter G-quadruplex DNA structures (hTERT G4) to downregulate hTERT expression. Ligand 5 showed high affinity toward hTERT G4 (Kd = 1.1 μM) and potent activity against triple-negative breast cancer cells (MDA-MB-231, IC50 = 1 μM). In cell-based assays, 5 not only exerts markedly inhibitory activity on classical telomere functions including decreased telomerase activity, shortened telomere length, and cellular senescence but also induces DNA damage, acute cellular senescence, and apoptosis. This study reveals that hTERT G4-targeting ligand may cause mitochondrial dysfunction, disrupt iron metabolism and activate ferroptosis in cancer cells. The in vivo antitumor efficacy of 5 was also evaluated in an MDA-MB-231 xenograft mouse model and approximately 78.7% tumor weight reduction was achieved. No observable toxicity against the major organs was observed.

Aging, Cancer, and Inflammation: The Telomerase Connection

Understanding the complex dynamics of telomere biology is important in the strong link between aging and cancer. Telomeres, the protective caps at the end of chromosomes, are central players in this connection. While their gradual shortening due to replication limits tumors expansion by triggering DNA repair mechanisms, it also promotes oncogenic changes within chromosomes, thus sustaining tumorigenesis. The enzyme telomerase, responsible for maintaining telomere length, emerges as a central player in this context. Its expression in cancer cells facilitates the preservation of telomeres, allowing them to circumvent the growth-limiting effects of short telomeres. Interestingly, the influence of telomerase extends beyond telomere maintenance, as evidenced by its involvement in promoting cell growth through alternative pathways. In this context, inflammation accelerates telomere shortening, resulting in telomere dysfunction, while telomere elements also play a role in modulating the inflammatory response. The recognition of this interplay has promoted the development of novel therapeutic approaches centered around telomerase inhibition. This review provides a comprehensive overview of the field, emphasizing recent progress in knowledge and the implications in understanding of cancer biology.

Flanking Effect on the Structure and Stability of Human Telomeric G-Quadruplex in Varying Salt Concentrations

The stability of the human telomere G-quadruplex (G4) is directly linked to cancer disease. The human telomere is mostly associated with the flanking nucleobases, which can affect the stability of G4. Hence, in this study, the effect of the flanking nucleobases in the context of their chemical nature, number, and position on the structure and stability of G4 has been investigated in varying concentrations of KCl mimicking the normal and cancer KCl microenvironments. The addition of flanking nucleobases does not alter the G4 topology. However, the presence of merely a single flanking nucleobase destabilizes the telomeric G4. This destabilizing effect is more prominent for thymine than adenine flanking nucleobase, probably due to the formation of the intermolecular G4 topology by thymine. Interestingly, the change in the stability of the telomeric G4 in the presence of thymine flanking nucleobase is sensitive to the concentration of KCl relevant to the normal and cancerous microenvironments, in contrast to adenine. Flanking nucleobases have a greater impact at the 5' end compared to the 3' end, particularly noticeable in KCl concentrations resembling the normal microenvironment rather than the cancerous one. These findings indicate that the effect of the flanking nucleobases on telomeric G4 is different in the KCl salt relevant to normal and cancerous microenvironments. This study may be helpful in attaining molecular-level insight into the role of G4 in telomeric length regulation under normal and cancerous KCl salt conditions.

Therapeutic Use of G4-Ligands in Cancer: State-of-the-Art and Future Perspectives

G-quadruplexes (G4s) are guanine-rich non-canonical secondary structures of nucleic acids that were identified in vitro almost half a century ago. Starting from the early 1980s, these structures were also observed in eukaryotic cells, first at the telomeric level and later in regulatory regions of cancer-related genes, in regulatory RNAs and within specific cell compartments such as lysosomes, mitochondria, and ribosomes. Because of the involvement of these structures in a large number of biological processes and in the pathogenesis of several diseases, including cancer, the interest in G4 targeting has exponentially increased in the last few years, and a great number of novel G4 ligands have been developed. Notably, G4 ligands represent a large family of heterogeneous molecules that can exert their functions by recognizing, binding, and stabilizing G4 structures in multiple ways. Regarding anti-cancer activity, the efficacy of G4 ligands was originally attributed to the capability of these molecules to inhibit the activity of telomerase, an enzyme that elongates telomeres and promotes endless replication in cancer cells. Thereafter, novel mechanisms through which G4 ligands exert their antitumoral activities have been defined, including the induction of DNA damage, control of gene expression, and regulation of metabolic pathways, among others. Here, we provided a perspective on the structure and function of G4 ligands with particular emphasis on their potential role as antitumoral agents. In particular, we critically examined the problems associated with the clinical translation of these molecules, trying to highlight the main aspects that should be taken into account during the phases of drug design and development. Indeed, taking advantage of the successes and failures, and the more recent technological progresses in the field, it would be possible to hypothesize the development of these molecules in the future that would represent a valid option for those cancers still missing effective therapies.

Smart Stimuli-Responsive Spherical Nucleic Acids: Cutting-Edge Platforms for Biosensing, Bioimaging, and Therapeutics

Spherical nucleic acids (SNAs) with exceptional colloidal stability, multiple modularity, and programmability are excellent candidates to address common molecular delivery-related issues. Based on this, the higher targeting accuracy and enhanced controllability of stimuli-responsive SNAs render them precise nanoplatforms with inestimable prospects for diverse biomedical applications. Therefore, tailored diagnosis and treatment with stimuli-responsive SNAs may be a robust strategy to break through the bottlenecks associated with traditional nanocarriers. Various stimuli-responsive SNAs are engineered through the incorporation of multifunctional modifications to meet biomedical demands with the development of nucleic acid functionalization. This review provides a comprehensive overview of prominent research in this area and recent advancements in the utilization of stimuli-responsive SNAs in biosensing, bioimaging, and therapeutics. For each aspect, SNA nanoplatforms that exhibit responsive behavior to both internal stimuli (including sequence, enzyme, redox reactions, and pH) and external stimuli (such as light and temperature) are highlighted. This review is expected to offer inspiration and guidance strategies for the rational design and development of stimuli-responsive SNAs in the field of biomedicine.

Shaping DNA damage responses: Therapeutic potential of targeting telomeric proteins and DNA repair factors in cancer

Shelterin proteins regulate genomic stability by preventing inappropriate DNA damage responses (DDRs) at telomeres. Unprotected telomeres lead to persistent DDR causing cell cycle inhibition, growth arrest, and apoptosis. Cancer cells rely on DDR to protect themselves from DNA lesions and exogenous DNA-damaging agents such as chemotherapy and radiotherapy. Therefore, targeting DDR machinery is a promising strategy to increase the sensitivity of cancer cells to existing cancer therapies. However, the success of these DDR inhibitors depends on other mutations, and over time, patients develop resistance to these therapies. This suggests the need for alternative approaches. One promising strategy is co-inhibiting shelterin proteins with DDR molecules, which would offset cellular fitness in DNA repair in a mutation-independent manner. This review highlights the associations and dependencies of the shelterin complex with the DDR proteins and discusses potential co-inhibition strategies that might improve the therapeutic potential of current inhibitors.

Revolutionizing personalized cancer treatment: the synergy of next-generation sequencing and CRISPR/Cas9

In the context of cancer heterogeneity, the synergistic action of next-generation sequencing (NGS) and CRISPR/Cas9 plays a promising role in the personalized treatment of cancer. NGS enables high-throughput genomic profiling of tumors and pinpoints specific mutations that primarily lead to cancer. Oncologists use this information obtained from NGS in the form of DNA profiling or RNA analysis to tailor precision strategies based on an individual's unique molecular signature. Furthermore, the CRISPR technique enables precise editing of cancer-specific mutations, allowing targeted gene modifications. Harnessing the potential insights of NGS and CRISPR/Cas9 heralds a remarkable frontier in cancer therapeutics with unprecedented precision, effectiveness and minimal off-target effects.

Evaluation of miR-130b-3p and miR-375 levels and telomere length with telomerase activity in prostate cancer

Prostate cancer (PC) is the most frequent cancer in males, as well as the second highest cause of cancer-related deaths in men. Differences in expression levels of miRNAs were linked with prostat cancer pathogenesis. qPCR was used to evaluate the expression of miR-130b-3p and miR-375 in Benign Prostate Hyperplasia (BPH (n = 20) and PC (n = 22, pre- and post-operative) patients plasma. Relative telomere lengths (RLTs) in genomic DNA isolated from plasma were measured with qPCR, and telomerase activity analyzed by the ELISA method. PSA levels of PC patients were greater than of BPH patients (p = 0.0473). miR-130b-3p and miR-375 levels were significantly lower in pre-operative specimens of PC patients according to BPH (p = 0,0362, p = 0.0168, respectively). Similarly, post-operative miR-375 levels were lower in PC patients than in BPH patients (p = 0.1866). BPH patients had shorter RTLs than PC patients in both pre- (p=0.0438) and post-operative (p=0.0297) specimens. Telomerase activity was higher in PC patients than BPH(p = 0.0129). Interestingly, telomerase activity was further increased after surgery (p = 0.0003). We aim to identify the levels of miR-130b-3p and miR-375 expression and their relationship with telomerase activity in PC patients. Our data suggest that miRNAs and telomere length (TL) with telomerase activity may play a role in regulating prostate tumorgenesis and may be used as biomarkers for PC diagnosis.

Telomerase Reverse Transcriptase-Promoter Mutation in Young Patients with Bladder Tumors

The TERT (Telomerase Reverse Transcriptase) gene promoter mutation is one of the most prevalent mutations in urothelial bladder tumors and this mutation is related to bladder tumor progression. Our purpose was to evaluate the presence of this mutation in a population of patients who were first diagnosed at age ≤ 40 years and to examine its relationship with tumor characteristics and progression. A molecular study was performed to detect the two most prevalent mutations in the TERT promoter (C228T and C250T). The study included 29 patients, with a mean follow-up of 152 months. There were no statistically significant differences in the clinical or tumor characteristics according to the presence or absence of the mutation. Although the mutation group showed poorer recurrence-free survival (RFS), there was no statistically significant difference and there was no difference in progression-free survival by group (p > 0.05). The pTERT mutations in bladder tumor cells occurred less frequently in younger patients than in older patients, a finding that could indicate different mechanisms of carcinogenesis. The trend towards lower RFS in patients with mutated pTERT needs to be confirmed by further studies, given the small number of patients included in these studies due to the low incidence of bladder tumors in this age group.

T cell senescence: a new perspective on immunotherapy in lung cancer

T cell senescence is an indication of T cell dysfunction. The ability of senescent T cells to respond to cognate antigens is reduced and they are in the late stage of differentiation and proliferation; therefore, they cannot recognize and eliminate tumor cells in a timely and effective manner, leading to the formation of the suppressive tumor microenvironment. Establishing methods to reverse T cell senescence is particularly important for immunotherapy. Aging exacerbates profound changes in the immune system, leading to increased susceptibility to chronic, infectious, and autoimmune diseases. Patients with malignant lung tumors have impaired immune function with a high risk of recurrence, metastasis, and mortality. Immunotherapy based on PD-1, PD-L1, CTLA-4, and other immune checkpoints is promising for treating lung malignancies. However, T cell senescence can lead to low efficacy or unsuccessful treatment results in some immunotherapies. Efficiently blocking and reversing T cell senescence is a key goal of the enhancement of tumor immunotherapy. This study discusses the characteristics, mechanism, and expression of T cell senescence in malignant lung tumors and the treatment strategies.

The dual effects of Congea chinensis Moldenke on inhibiting tumor cell proliferation and delaying aging by activating TERT transcriptional activity

ETHNOPHARMACOLOGICAL RELEVANCE

Natural medicinal plants, also named herbs, have attracted considerable research attention for their potential pharmacological activities, such as antitumor and longevity-promoting activities. Our previous review proposed that maintaining the homeostatic balance between aging and cancer may benefit organisms to enable tumor-free longevity. Congea chinensis Moldenke (CCM) is a plant species that grows on the border of Yunnan Province of China. Its medicinal value has been few reports until now. Thus, screening and extraction the ingredients from CCM that are both active tumor suppressors and TERT activators is a therapeutic strategy for improving tumor-free longevity.

AIM OF THE STUDY

To extract and evaluate the cytotoxic antitumor and TERT transcription-promoting activities of the plant CCM.

MATERIALS AND METHODS

The ingredients extracted from CCM were tested for transcriptional activation of p53 using pGL4-p53-GFP cells and for TERT expression using a real-time PCR assay. In vitro antitumor activity was detected by sulforhodamine B (SRB) assay and Annexin V/PI staining assay. The cell-permeable probe H2DCFDA was used to detect intracellular reactive oxygen species (ROS). Western blot was performed to verify predicated proteins regulated by the ingredients. RNA-sequence analysis was applied to predicate the underlying mechanism of CCM.

RESULTS

Both CCM and MPRC2-8, two novel extracts of Congea chinensis Moldenke, activated the expression of p53 and TERT and were selectively cytotoxic toward tumor cells. In addition, the cytotoxic mechanism of MPRC2-8 was identified as ROS generation-induced apoptosis. Interestingly, MPRC2-8 showed opposite regulatory effects on the SIRT1-p53 axis in A549 and HT-29 cells, which have different p53 statuses. RNA-seq analysis showed that CCM and MPRC2-8 induced the p53, apoptosis and ROS signaling pathways, consistent with the results of cellular experiments in vitro.

CONCLUSION

Our study reveals that CCM and MPRC2-8 have two complementary activities, antitumor activity and TERT-activating activity, with potential antitumor and longevity-improving effects.

Unlocking longevity: the role of telomeres and its targeting interventions

Average life expectancy has been steadily increasing in developed countries worldwide. These demographic changes are associated with an ever-growing social and economic strain to healthcare systems as well as society. The aging process typically manifests as a decline in physiological and cognitive functions, accompanied by a rise in chronic diseases. Consequently, strategies that both mitigate age-related diseases and promote healthy aging are urgently needed. Telomere attrition, characterized by the shortening of telomeres with each cell division, paradoxically serves as both a protective mechanism and a contributor to tissue degeneration and age-related ailments. Based on the essential role of telomere biology in aging, research efforts aim to develop approaches designed to counteract telomere attrition, aiming to delay or reduce age-related diseases. In this review, telomere biology and its role in aging and age-related diseases is summarized along with recent approaches to interfere with telomere shortening aiming at well- and healthy-aging as well as longevity. As aging research enters a new era, this review emphasizes telomere-targeting therapeutics, including telomerase activators and tankyrase inhibitors, while also exploring the effects of antioxidative and anti-inflammatory agents, along with indirectly related approaches like statins.

Retrospective Analysis of the Clinical Characteristics of Patients with Breast Cancer Treated with Telomerase Peptide Immunotherapy Combined with Cytotoxic Chemotherapy

Purpose

Telomerase activation, a critical step in cancer progression, occurs in approximately 95% of breast cancer cases. Telomerase is an attractive therapeutic target for breast cancer owing to its unique expression pattern. GV1001, a telomerase-derived peptide, is loaded onto human leukocyte antigen (HLA) class II antigen-presenting cells and binds to CD4+ T cell activating immune responses. This study aimed to evaluate the effectiveness and safety of co-administration of GV1001 and cytotoxic chemotherapy in patients with heavily-treated metastatic breast cancer.

Patients and methods

We analyzed 63 patients with breast cancer who received both GV1001 and cytotoxic chemotherapy. The GV 1001 administration methods involves 0.56 mg intradermal injection three times during the first week, one time at weeks 2, 3, 4, and 6, and then once every 28 days. The primary endpoint of this study was quality of life according to EORTC QLO-C30 and EQ-5D, while the secondary endpoint was the antitumor response according to RECIST 1.1, progression-free survival, overall survival, and toxicity profile.

Results

In 34 patients with HR+ breast cancer evaluable for tumor response, the disease control rate (DCR) and overall response rate (ORR) were 58.8% and 26.4%, respectively. The DCR and ORR were 66.6% and 28.5% in 21 patients with HER-2+ and 50% and 25% in patients with triple-negative breast cancer (TNBC), respectively. The median progression free survival was 10.4, 8.7, and 5.6 months in HR+, HER-2+, TNBC, respectively. The overall survival was 19.7, 13.2, and 9.4 months for patients with HR+, HER-2+, and TNBC, respectively. Most patients had an improved quality of life with statistically significant differences in some variables. The patients in this study experienced no additional toxicities other than the cytotoxic chemotherapy-associated side effects.

Conclusion

GV1001 is a relatively safe anticancer vaccine for patients with heavily-treated breast cancer and can to improve the quality of life.

Telomerase and hallmarks of cancer: An intricate interplay governing cancer cell evolution

Transformed cells must acquire specific characteristics to be malignant. Weinberg and Hanahan characterize these characteristics as cancer hallmarks. Though these features are independently driven, substantial signaling crosstalk in transformed cells efficiently promotes these feature acquisitions. Telomerase is an enzyme complex that maintains telomere length. However, its main component, Telomere reverse transcriptase (TERT), has been found to interact with various signaling molecules like cMYC, NF-kB, BRG1 and cooperate in transcription and metabolic reprogramming, acting as a strong proponent of malignant features such as cell death resistance, sustained proliferation, angiogenesis activation, and metastasis, among others. It allows cells to avoid replicative senescence and achieve endless replicative potential. This review summarizes both the canonical and noncanonical functions of TERT and discusses how they promote cancer hallmarks. Understanding the role of Telomerase in promoting cancer hallmarks provides vital insight into the underlying mechanism of cancer genesis and progression and telomerase intervention as a possible therapeutic target for cancer treatment. More investigation into the precise molecular mechanisms of telomerase-mediated impacts on cancer hallmarks will contribute to developing more focused and customized cancer treatment methods.

Olovnikov, Telomeres, and Telomerase. Is It Possible to Prolong a Healthy Life?

The science of telomeres and telomerase has made tremendous progress in recent decades. In this review, we consider it first in a historical context (the Carrel-Hayflick-Olovnikov-Blackburn chain of discoveries) and then review current knowledge on the telomere structure and dynamics in norm and pathology. Central to the review are consequences of the telomere shortening, including telomere position effects, DNA damage signaling, and increased genetic instability. Cell senescence and role of telomere length in its development are discussed separately. Therapeutic aspects and risks of telomere lengthening methods including use of telomerase and other approaches are also discussed.

Effects of hTERT transfection on the telomere and telomerase of Periplaneta americana cells in vitro

Telomere and telomerase are crucial factors in cell division and chromosome stability. Telomerase activity in most cells depends on the transcription control by the telomerase reverse transcriptase (TERT). The introduction of an exogenous human TERT (hTERT) in cultured cells could enhance telomerase activity and elongate the lifespan of various cells. Telomere elongation mechanisms vary between insects and are complex and unusual. Whether the use of exogenous hTERT can immortalize primary insect cells remains to be investigated. In this study, we used a recombinant virus expressing hTERT to infect primary cultured cells of Periplaneta americana and evaluated its effects on insect cell immortalization. We found that hTERT was successfully expressed and promoted the growth of P. americana cells, shortening their doubling time. This was due to the ability of hTERT to increase the activity of telomerase in P. americana cells, thus prolonging the telomeres. Our study lays the foundation for understanding the mechanisms of telomere elongation in P. americana, and suggests that the introduction of hTERT into insect cells could be an efficient way to establish certain insect cell lines.

Cigarette smoke extract induces the senescence of endothelial progenitor cells by upregulating p300

INTRODUCTION

Endothelial progenitor cells (EPCs) are the main source of endothelial cells. The senescence of EPCs is involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cigarette smoke extract (CSE) can directly induce the dysfunction and increased expression of senescence-related markers in EPCs cultured in vitro. Histone acetyltransferase p300 is a transcriptional activator, and its changes can lead to cell senescence. The present study investigated whether CSE can induce the senescence of EPCs by upregulating p300.

METHODS

EPCs were isolated from bone marrow of C57BL/6J mice by density gradient centrifugation. The p300 inhibitor C646 and agonist CTPB were used to interfere with EPCs, cell cycle and apoptosis were detected by flow cytometry, the proportion of senile cells was counted by β-galactosidase staining, the protein expression of p300, H4K12, Cyclin D1, TERT and Ki67 were detected by western blot.

RESULTS

Compared with the control group, the cell cycle of CSE group and CTPB group were blocked, the apoptosis rate and early apoptosis rate were increased, the proportion of senile cells counted by β-galactosidase staining was increased, the expression of p300 and H4K12 protein were increased, the expression of Cyclin D1, TERT and Ki67 protein were decreased. C646 could partly alleviate the damages caused by CSE.

CONCLUSIONS

CSE may promote the apoptosis and senescence of EPCs by upregulating the expression of p300 and H4K12 protein, thus preventing the transition of EPCs from G1 phase to S phase, affecting telomerase synthesis, and reducing EPCs proliferation.

Telomere length and hTERT genetic variants as potential prognostic markers in multiple myeloma

Telomere dysfunction is a notable event observed in many cancers contributing to their genomic instability. A major factor controlling telomere stability is the human telomerase reverse transcriptase catalytic subunit (hTERT). Telomere shortening has been observed in multiple myeloma (MM), a plasma cell malignancy with a complex and heterogeneous genetic background. In the present study, we aimed to analyse telomere length and hTERT genetic variants as potential markers of risk and survival in 251 MM patients. We found that telomere length was significantly shorter in MM patients than in healthy individuals, and patients with more advanced disease (stage III according to the International Staging System) had shorter telomeres than patients with less advanced disease. MM patients with hTERT allele rs2736100 T were characterized with significantly shorter progression-free survival (PFS). Moreover, allele rs2736100 T was also found to be less common in patients with disease progression in response to treatment. hTERT rs2853690 T was associated with higher haemoglobin blood levels and lower C-reactive protein. In conclusion, our results suggest that telomere length and hTERT genetic variability may affect MM development and can be potential prognostic markers in this disease.

The shelterin protein expansion of telomere dynamics: Linking early life adversity, life history, and the hallmarks of aging

Aging is characterized by functional decline occurring alongside changes to several hallmarks of aging. One of the hallmarks includes attrition of repeated DNA sequences found at the ends of chromosomes called telomeres. While telomere attrition is linked to morbidity and mortality, whether and how it causally contributes to lifelong rates of functional decline is unclear. In this review, we propose the shelterin-telomere hypothesis of life history, in which telomere-binding shelterin proteins translate telomere attrition into a range of physiological outcomes, the extent of which may be modulated by currently understudied variation in shelterin protein levels. Shelterin proteins may expand the breadth and timing of consequences of telomere attrition, e.g., by translating early life adversity into acceleration of the aging process. We consider how the pleiotropic roles of shelterin proteins provide novel insights into natural variation in physiology, life history, and lifespan. We highlight key open questions that encourage the integrative, organismal study of shelterin proteins that enhances our understanding of the contribution of the telomere system to aging.

Prognosis signature for predicting the survival and immunotherapy response in esophageal carcinoma based on cellular senescence-related genes

Background

Cellular senescence occurs throughout life and can play beneficial roles in a variety of physiological processes, including embryonic development, tissue repair, and tumor suppression. However, the relationship between cellular senescence-related genes (CSRGs) and immunotherapy in esophageal carcinoma (ECa) remains poorly defined.

Methods

The data set used in the analysis was retrieved from TCGA (Research Resource Identifier (RRID): SCR_003193), GEO (RRID: SCR_005012), and CellAge databases. Data processing, statistical analysis, and diagram formation were conducted in R software (RRID: SCR_001905) and GraphPad Prism (RRID: SCR_002798). Based on CSRGs, we used the TCGA database to construct a prognostic signature for ECa and then validated it in the GEO database. The predictive efficiency of the signature was evaluated using receiver operating characteristic (ROC) curves, Cox regression analysis, nomogram, and calibration curves. According to the median risk score derived from CSRGs, patients with ECa were divided into high- and low-risk groups. Immune infiltration and immunotherapy were also analyzed between the two risk groups. Finally, the hub genes of the differences between the two risk groups were identified by the STRING (RRID: SCR_005223) database and Cytoscape (RRID: SCR_003032) software.

Results

A six-gene risk signature (DEK, RUNX1, SMARCA4, SREBF1, TERT, and TOP1) was constructed in the TCGA database. Patients in the high-risk group had a worse overall survival (OS) was disclosed by survival analysis. As expected, the signature presented equally prognostic significance in the GSE53624 cohort. Next, the Area Under ROC Curve (AUC=0.854) and multivariate Cox regression analysis (HR=3.381, 2.073-5.514, P<0.001) also proved that the risk signature has a high predictive ability. Furthermore, we can more accurately predict the prognosis of patients with ECa by nomogram constructed by risk score. The result of the TIDE algorithm showed that ECa patients in the high-risk group had a greater possibility of immune escape. At last, a total of ten hub genes (APOA1, MUC5AC, GC, APOA4, AMBP, FABP1, APOA2, SOX2, MUC8, MUC17) between two risk groups with the highest interaction degrees were identified. By further analysis, four hub genes (APOA4, AMBP, FABP1, and APOA2) were related to the survival differences of ECa.

Conclusions

Our study reveals comprehensive clues that a novel signature based on CSRGs may provide reliable prognosis prediction and insight into new therapy for patients with ECa.

Pathology of Hepatocellular Carcinoma and Tumor-Bearing Liver Tissue in Association with hTERT Promoter Mutation

Background

The hTERT promoter mutation represents a common and early event in hepatocarcinogenesis, but its linkage to the morphological status of the underlying liver tissue is poorly understood. We analyzed the connection between the histopathological changes in tumor-bearing liver tissue and the occurrence of the hTERT promoter mutation in hepatocellular carcinoma (HCC), correlated with clinical data.

Methods

The study cohort comprised 160 histologically confirmed HCC in patients with or without cirrhosis that were investigated for the hTERT promoter mutation. We evaluated the frequency of the hTERT promoter mutation in patients with HCC with or without cirrhosis and correlated it with potential clinical and histopathological drivers. In particular, we examined tumor-bearing noncirrhotic liver tissue regarding inflammation; the modified histological activity index (mHAI), fibrosis, and steatosis; and its correlation with the frequency of the hTERT promoter mutation in HCC. We evaluated overall survival with multivariate Cox regression. Furthermore, we compared hTERT antibody immunohistochemistry and molecular hTERT promoter mutation analysis of both HCC and background liver tissue.

Results

The hTERT promoter mutation was especially related to HCC in cirrhotic compared with noncirrhotic liver (p < 0.001) and independently of cirrhosis in patients ≥ 60 years (p = 0.005). Furthermore, the hTERT promoter mutation was associated with cirrhosis caused by alcohol toxicity and hepatitis C virus infection. In noncirrhotic liver tissue, the frequency of hTERT-promoter-mutated HCC increased with the degree of inflammation and fibrosis. Nevertheless, 25% of the hTERT-promoter-mutated HCC developed in normal liver tissue without HCC risk factors. Multivariate Cox regression analysis did not reveal an influence of the hTERT promoter mutation in HCC on overall survival at 3, 5, and 16 years. Immunohistochemical analysis with the hTERT antibodies LS-B95 and 2D8 in hTERT-promoter-mutated HCC and hTERT-wildtype HCC showed a mildly stronger immunoreaction compared with the tumor-bearing liver tissue (LS-B95: p < 0.01, 2D8: p < 0.01).

Conclusions

Our study reveals a connection between pathological changes in tumor-bearing liver tissue and the hTERT promoter mutation in most HCC, even in noncirrhotic liver tissue. Immunohistochemical hTERT antibodies do not discriminate between hTERT-promoter-mutated and wildtype HCC.

ctDNA as a novel and promising approach for cancer diagnosis: a focus on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent forms of cancer worldwide. Therefore, it is essential to diagnose and treat HCC patients promptly. As a novel discovery, circulating tumor DNA (ctDNA) can be used to analyze the tumor type and the cancer location. Additionally, ctDNA assists the cancer stage determination, which enables medical professionals to provide patients with the most appropriate treatment. This review will discuss the HCC-related mutated genes diagnosed by ctDNA. In addition, we will introduce the different and the most appropriate ctDNA diagnosis approaches based on the facilities.

Prognostic role and interaction of TERT promoter status, telomere length and MGMT promoter methylation in newly diagnosed IDH wild-type glioblastoma patients

BACKGROUND

The clinical relevance of promoter mutations and single nucleotide polymorphism rs2853669 of telomerase reverse transcriptase (TERT) and telomere length in patients with isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM) patients remains unclear. Moreover, some studies speculated that TERT promoter status might influence the prognostic role of O6-methylguanine DNA methyltransferase (MGMT) promoter methylation in newly diagnosed GBM. We carried out a large study to investigate their clinical impact and their interaction in newly diagnosed GBM patients.

PATIENTS AND METHODS

We included 273 newly diagnosed IDH wild-type GBM patients who started treatment at Veneto Institute of Oncology IOV - IRCCS (Padua, Italy) from December 2016 to January 2020. TERT promoter mutations (-124 C>T and -146 C>T) and SNP rs2853669 (-245 T>C), relative telomere length (RTL) and MGMT methylation status were retrospectively assessed in this prospective cohort of patients.

RESULTS

Median overall survival (OS) of 273 newly diagnosed IDH wild-type GBM patients was 15 months. TERT promoter was mutated in 80.2% of patients, and most had the rs2853669 single nucleotide polymorphism as T/T genotype (46.2%). Median RTL was 1.57 (interquartile range 1.13-2.32). MGMT promoter was methylated in 53.4% of cases. At multivariable analysis, RTL and TERT promoter mutations were not associated with OS or progression-free survival (PFS). Notably, patients C carrier of rs2853669 (C/C+C/T genotypes) showed a better PFS compared with those with the T/T genotype (hazard ratio 0.69, P = 0.007). In terms of OS and PFS, all interactions between MGMT, TERT and RTL and between TERT and rs2853669 genotype were not statistically significant.

CONCLUSIONS

Our findings suggest the presence of the C variant allele at the rs2853669 of the TERT promoter as an attractive independent prognostic biomarker of disease progression in IDH wild-type GBM patients. RTL and TERT promoter mutational status were not correlated to survival regardless of MGMT methylation status.

The Role of Natural Flavonoids as Telomerase Inhibitors in Suppressing Cancer Growth

Cancer is a complex and multifaceted group of diseases characterized by the uncontrolled growth and spread of abnormal cells. While cancer can be challenging and life-altering, advances in research and development have led to the identification of new promising anti-cancer targets. Telomerase is one such target that is overexpressed in almost all cancer cells and plays a critical role in maintaining telomere length, which is essential for cell proliferation and survival. Inhibiting telomerase activity can lead to telomere shortening and eventual cell death, thus presenting itself as a potential target for cancer therapy. Naturally occurring flavonoids are a class of compounds that have already been shown to possess different biological properties, including the anti-cancer property. They are present in various everyday food sources and richly present in fruits, nuts, soybeans, vegetables, tea, wine, and berries, to name a few. Thus, these flavonoids could inhibit or deactivate telomerase expression in cancer cells by different mechanisms, which include inhibiting the expression of hTERT, mRNA, protein, and nuclear translocation, inhibiting the binding of transcription factors to hTERT promoters, and even telomere shortening. Numerous cell line studies and in vivo experiments have supported this hypothesis, and this development could serve as a vital and innovative therapeutic option for cancer. In this light, we aim to elucidate the role of telomerase as a potential anti-cancer target. Subsequently, we have illustrated that how commonly found natural flavonoids demonstrate their anti-cancer activity via telomerase inactivation in different cancer types, thus proving the potential of these naturally occurring flavonoids as useful therapeutic agents.

TERT promoter mutations in head and neck squamous cell carcinoma: A systematic review and meta-analysis on prevalence and prognostic significance

OBJECTIVES

To estimate the prevalence of two most common and mutually exclusive -124 C > T and -146 C > T TERT promoter mutations in HNSCC and analyse their prognostic role.

MATERIALS AND METHODS

The databases Medline (via Ovid), Embase (via Ovid), Cochrane Library, Scopus, and Web of Science (Core Collection) were searched from inception to December 2022 to identify studies analysing TERT promoter mutations in HNSCC. Pooled prevalence of TERT promoter mutations and hazard ratio (sHR) of death/progression, with corresponding confidence intervals (CI), were estimated.

RESULTS

The initial search returned 6416 articles, of which 17 studies, including 1830 patients, met the criteria for prevalence meta-analysis. Among them, 8 studies fitted the inclusion criterion to analyse the prognostic impact of TERT promoter mutations. Overall, 21% (95% CI: 12%-31%) of HNSCCs harboured TERT promoter mutation. TERT promoter mutations were more commonly found in oral cavity cancer (prevalence = 47%, 95% CI: 33%-61%), followed by laryngeal/hypopharyngeal cancer (prevalence = 12%, 95% CI: 4%-25%), while they were quite rare in oropharyngeal cancer (prevalence = 1%, 95% CI: 0%-4%). TERT promoter mutation -124 C > T was associated with a higher risk of death (sHR = 2.01, 95% CI: 1.25-3.23) and progression (sHR = 2.79, 95% CI: 1.77-4.40), while -146 C > T TERT promoter mutation did not show any significant correlation neither to overall nor progression-free survival.

CONCLUSION

TERT promoter mutations were mainly topographically restricted to oral cavity cancer. -124 C > T was the most common TERT promoter mutation and was significantly associated to worse outcome in HNSCC.

Multiple Actions of Telomerase Reverse Transcriptase in Cell Death Regulation

Telomerase reverse transcriptase (TERT), a core part of telomerase, has been known for a long time only for its telomere lengthening function by reverse transcription of RNA template. Currently, TERT is considered as an intriguing link between multiple signaling pathways. The diverse intracellular localization of TERT corresponds to a wide range of functional activities. In addition to the canonical function of protecting chromosome ends, TERT by itself or as a part of the telomerase complex participates in cell stress responses, gene regulation and mitochondria functioning. Upregulation of TERT expression and increased telomerase activity in cancer and somatic cells relate to improved survival and persistence of such cells. In this review, we summarize the data for a comprehensive understanding of the role of TERT in cell death regulation, with a focus on the interaction of TERT with signaling pathways involved in cell survival and stress response.

The role of miR-155 on liver diseases by modulating immunity, inflammation and tumorigenesis

The liver is a well-known metabolic organ that can be susceptible to external stimuli to affect its normal physiological function. Worldwide, the morbidity and mortality of liver diseases are skyrocketing every year, causing human health crises. Recently, new approaches such as biotechnology have been introduced to achieve optimal treatment and prognostic management of liver diseases. microRNAs (miRNAs), a kind of small non-coding RNA molecule, have the advantages of biodiversity, wide distribution and numerous members. Among these miRNAs, miR-155 is an important regulator of inflammation, immunity and tumorigenesis. In this review, the PubMed and Web of Science databases were searched from 2009 to 2022. After inclusion and exclusion, 64 articles were selected for a systematic review to comprehensively summarize the mechanisms of miR-155 regulating inflammation, immunity and tumorigenesis in liver diseases and liver cancer, covering in vitro, in vivo and clinical studies. Existing preclinical studies and clinical trials have listed that the up-regulation and down-regulation of miR-155 are significant in alcoholic liver injury, viral hepatitis, autoimmune hepatitis, infectious liver injury, liver transplantation and liver cancer. The immune and inflammation effects of miR-155 are manifested by regulating macrophage polarization, NK cell killing, Th17 cell and Th1/Th2 cell differentiation. Additionally, miR-155 is also committed to participating in the cell cycle, invasion and metastasis, immune escape and other processes to promote and intensify the development of liver cancer. In conclusion, miR-155 is not only a biomarker for the diagnosis and prognosis of liver diseases, but also plays a therapeutic role via regulating immunity, inflammation and tumorigenesis.

Biological and clinical perspectives of TERT promoter mutation detection on bladder cancer diagnosis and management

The telomerase reverse transcriptase (TERT) promoter mutations are associated with increased TERT mRNA and TERT protein levels, telomerase activity, and shorter but stable telomere length. TERT promoter mutation is the most common mutation that occurs in approximately 60-80% of patients with bladder cancer. The TERT promoter mutations occur in a wide spectrum of urothelial lesions, including benign urothelial proliferation and tumor-like conditions, benign urothelial tumors, premalignant and putative precursor lesions, urothelial carcinoma and its variants, and nonurothelial malignancies. The prevalence and incidence of TERT promoter mutations in a total of 7259 cases from the urinary tract were systematically reviewed. Different platforms of TERT promoter mutation detection were presented. In this review, we also discussed the significance and clinical implications of TERT promoter mutation detection in urothelial tumorigenesis, surveillance and early detection, diagnosis, differential diagnosis, prognosis, prediction of treatment responses, and clinical outcome. Identification of TERT promoter mutations from urine or plasma cell-free DNA (liquid biopsy) will facilitate bladder cancer screening program and optimal clinical management. A better understanding of TERT promoter mutation and its pathway would open new therapeutic avenues for patients with bladder cancer.

Transcriptional analysis links B cells and TERT expression to favorable prognosis in head and neck cancer

Telomerase reverse transcriptase (TERT) is a conserved self-tumor antigen overexpressed in ∼85% of tumor cells and is immunogenic in cancer patients. The effect of TERT expression on the regulation of intratumor adaptive immunity has not yet been investigated. We used RNA sequencing data from The Cancer Genome Atlas (TCGA) in 11 solid tumor types to investigate potential interactions between TERT expression, and B and T cell infiltrate in the tumor microenvironment. We found a positive correlation between TERT expression, B and T cells in four cancer types with the strongest association in head and neck squamous cell carcinoma (HSNCC). In HNSCC a Bhigh/TERThigh signature was associated with improved progression-free survival (PFS) (P = 0.0048). This effect was independent of HPV status and not shared in comparable analysis by other conserved tumor antigens (NYESO1, MUC1, MAGE, and CEA). Bhigh/TERThigh HNSCC tumors also harbored evidence of tertiary lymphoid structure (TLS) such as signatures for germinal center (GC) and switched memory B cells, central memory CD4 and effector memory CD8 T cells. Bhigh/TERThigh HNSCC tumors also showed an up-regulation of genes and pathways related to B and T cell activation, proliferation, migration, and cytotoxicity, while factors associated with immunosuppression and cancer cell invasiveness were down-regulated. In summary, our study uncovers a new association between high TERT expression and high B cell infiltrate in HNSCC, suggesting a potential benefit from therapeutic strategies that invigorate intratumor TERT-mediated T-B cooperation.

Simultaneous Imaging and Visualizing the Association of Survivin mRNA and Telomerase in Living Cells by Using a Dual-Color Encoded DNA Nanomachine

Simultaneous imaging and especially visualizing the association of survivin mRNA and telomerase in living cells are of great value for the diagnosis and prognosis of cancer because their co-expression facilitates the development of cancer and identifies patients at high risk of tumor-related death. The challenge is to develop methods that enable visualizing the association of multiplex targets and avoid the distorted signals due to the different delivery efficiency of probes. Herein, we engineered a DNA triangular prism nanomachine (DTPN) for simultaneous multicolor imaging of survivin mRNA and telomerase and visualizing their association in living cells. Two recognizing probes targeted survivin mRNA and telomerase, and the reporter probe was assembled on the DTP in equal amounts, ensuring the same delivery efficiency of the probes to the living cells. The results showed that this DTPN could quantify intracellular survivin mRNA expression and telomerase activity. Moreover, it also enabled us to visualize the effect of the down-regulation of one target on the expression of another target under different drug stimulations. The results implied that our DTPN provided a promising platform for cancer diagnosis, prognosis, drug screening, and related biological research.

Alternative Lengthening of Telomeres (ALT) and Telomerase Reverse Transcriptase Promoter Methylation in Recurrent Adult and Primary Pediatric Pituitary Neuroendocrine Tumors

Neoplastic cells acquire the ability to proliferate endlessly by maintaining telomeres via telomerase, or alternative lengthening of telomeres (ALT). The role of telomere maintenance in pituitary neuroendocrine tumors (PitNETs) has yet to be thoroughly investigated. We analyzed surgical samples of 24 adult recurrent PitNETs (including onset and relapses for 14 of them) and 12 pediatric primary PitNETs. The presence of ALT was assessed using telomere-specific fluorescence in situ hybridization, methylation of telomerase reverse transcriptase promoter (TERTp) by methylation-specific PCR, and ATRX expression by immunohistochemistry. Among the adult recurrent PitNETs, we identified 3/24 (12.5%) ALT-positive cases. ALT was present from the onset and maintained in subsequent relapses, suggesting that this mechanism occurs early in tumorigenesis and is stable during progression. ATRX loss was only seen in one ALT-positive case. Noteworthy, ALT was observed in 3 out of 5 aggressive PitNETs, including two aggressive corticotroph tumors, eventually leading to patient's death. ALT-negative tumors (87.5%) were classified according to their low (29.2%), medium (50%), and high (8.3%) telomere fluorescence intensity, with no significant differences emerging in their molecular, clinical, or pathological characteristics. TERTp methylation was found in 6/24 cases (25%), with a total concordance in methylation status between onset and recurrences, suggesting that this mechanism remains stable throughout disease progression. TERTp methylation did not influence telomere length. In the pediatric cohort of PitNETs, TERTp methylation was also observed in 4/12 cases (33.3%), but no case of ALT activation was observed. In conclusion, ALT is triggered at onset and maintained during tumor progression in a subset of adult PitNETs, suggesting that it could be used for clinical purposes, as a potential predictor of aggressive behavior.

Massively parallel reporter assays and variant scoring identified functional variants and target genes for melanoma loci and highlighted cell-type specificity

The most recent genome-wide association study (GWAS) of cutaneous melanoma identified 54 risk-associated loci, but functional variants and their target genes for most have not been established. Here, we performed massively parallel reporter assays (MPRAs) by using malignant melanoma and normal melanocyte cells and further integrated multi-layer annotation to systematically prioritize functional variants and susceptibility genes from these GWAS loci. Of 1,992 risk-associated variants tested in MPRAs, we identified 285 from 42 loci (78% of the known loci) displaying significant allelic transcriptional activities in either cell type (FDR < 1%). We further characterized MPRA-significant variants by motif prediction, epigenomic annotation, and statistical/functional fine-mapping to create integrative variant scores, which prioritized one to six plausible candidate variants per locus for the 42 loci and nominated a single variant for 43% of these loci. Overlaying the MPRA-significant variants with genome-wide significant expression or methylation quantitative trait loci (eQTLs or meQTLs, respectively) from melanocytes or melanomas identified candidate susceptibility genes for 60% of variants (172 of 285 variants). CRISPRi of top-scoring variants validated their cis-regulatory effect on the eQTL target genes, MAFF (22q13.1) and GPRC5A (12p13.1). Finally, we identified 36 melanoma-specific and 45 melanocyte-specific MPRA-significant variants, a subset of which are linked to cell-type-specific target genes. Analyses of transcription factor availability in MPRA datasets and variant-transcription-factor interaction in eQTL datasets highlighted the roles of transcription factors in cell-type-specific variant functionality. In conclusion, MPRAs along with variant scoring effectively prioritized plausible candidates for most melanoma GWAS loci and highlighted cellular contexts where the susceptibility variants are functional.

Characterization of TGF-β signaling in a human organotypic skin model reveals that loss of TGF-βRII induces invasive tissue growth

Transforming growth factor–β (TGF-β) signaling regulates various aspects of cell growth and differentiation and is often dysregulated in human cancers. We combined genetic engineering of a human organotypic three-dimensional (3D) skin model with global quantitative proteomics and phosphoproteomics to dissect the importance of essential components of the TGF-β signaling pathway, including the ligands TGF-β1, TGF-β2, and TGF-β3, the receptor TGF-βRII, and the intracellular effector SMAD4. Consistent with the antiproliferative effects of TGF-β signaling, the loss of TGF-β1 or SMAD4 promoted cell cycling and delayed epidermal differentiation. The loss of TGF-βRII, which abrogates both SMAD4-dependent and SMAD4-independent downstream signaling, more strongly affected cell proliferation and differentiation than did loss of SMAD4, and it induced invasive growth. TGF-βRII knockout reduced cell-matrix interactions, and the production of matrix proteins increased the production of cancer-associated cell-cell adhesion proteins and proinflammatory mediators and increased mitogen-activated protein kinase (MAPK) signaling. Inhibiting the activation of the ERK and p38 MAPK pathways blocked the development of the invasive phenotype upon the loss of TGF-βRII. This study provides a framework for exploring TGF-β signaling pathways in human epithelial tissue homeostasis and transformation using genetic engineering, 3D tissue models, and high-throughput quantitative proteomics and phosphoproteomics.

Adult Granulosa Cell Tumor With Sarcomatous Transformation: A Case Study With Emphasis on Molecular Alterations

Adult granulosa cells tumors (AGCTs) are typically low-grade indolent tumors. On rare occasions, they undergo high-grade/sarcomatous transformation and behave aggressively. This transformation is postulated to occur as the result of acquired genetic alterations, some of which may be eligible for targeted therapy. Here we report a rare case of AGCT with sarcomatous transformation that harbored distinct molecular alterations from those typically seen with AGCTs supporting a molecularly driven approach to these malignancies. The patient is a 56-yr-old G3P3 woman with a history of multiple recurrences of ovarian AGCT for which the first diagnosis was made at the age of 25 when she was evaluated for infertility. The ovarian tumor displayed typical features of AGCT with low-grade, bland morphology. The first extraovarian spread of tumor involving the cul-de-sac was reported at the age of 39. After that, recurrences occurred every 2 to 3 yr with involvement of multiple anatomic sites and repeated surgical resections. At the age of 55 she developed a symptomatic recurrence in the pelvis and underwent resection of an isolated lesion (specimen 1) to no gross residual disease. Within 4 wk of resection she developed significant pelvic pain and imaging showed recurrence of the mass. Therefore, in 5 mo after the initial resection she underwent repeat excision of the lesion (specimen 2) and associated bowel. The sections from specimen 1 showed a biphasic morphology: a low-grade component with morphology and immunophenotype consistent with a typical AGCT and a high-grade spindle cell component with features consistent with a high-grade sarcoma. Specimen 2 featured a pure high-grade sarcoma characterized by coagulative tumor cell necrosis, readily recognizable mitoses, highly atypical cells with vesicular nuclei and prominent nucleoli. SF-1 positivity and the presence of FOXL2 C134W mutation in the sarcomatous component support the notion of transformation of typical AGCT. While detected TERT promoter C228T mutation may play a role in this process, we further identified genetic alterations affecting PI3K/AKT/mTOR pathway, including mutations in PIK3CA , PIK3R1 , AKT1 , and NF2 , which may also contribute to tumor progression/transformation. These findings provide rationale for molecular/pathway-based targeted therapy for patients with advanced AGCT.

Obesity: a perfect storm for carcinogenesis

Obesity-related cancers account for 40% of the cancer cases observed in the USA and obesity is overtaking smoking as the most widespread modifiable risk factor for carcinogenesis. Here, we use the hallmarks of cancer framework to delineate how obesity might influence the carcinogenic hallmarks in somatic cells. We discuss the effects of obesity on (a) sustaining proliferative signaling; (b) evading growth suppressors; (c) resisting cell death; (d) enabling replicative immortality; (e) inducing angiogenesis; (f) activating invasion and metastasis; (g) reprogramming energy metabolism; and (h) avoiding immune destruction, together with its effects on genome instability and tumour-promoting inflammation. We present the current understanding and controversies in this evolving field, and highlight some areas in need of further cross-disciplinary focus. For instance, the relative importance of the many potentially causative obesity-related factors is unclear for each type of malignancy. Even within a single tumour type, it is currently unknown whether one obesity-related factor consistently plays a predominant role, or if this varies between patients or, even in a single patient with time. Clarifying how the hallmarks are affected by obesity may lead to novel prevention and treatment strategies for the increasingly obese population.

C-reactive protein and telomerase reverse transcriptase (TERT) associate with chronic disease markers in a sample from low-income neighborhoods in Detroit, Michigan

Racial and ethnic minorities in economically deprived inner cities experience high rates of chronic diseases compared to neighborhoods with higher socioeconomic status (SES). However, these economically deprived populations are understudied in terms of biomarkers associated with chronic disease risk which include C-reactive protein (CRP), telomerase reverse transcriptase (TERT), and glycosylated hemoglobin (A1C). We examined relationships between CRP and TERT and chronic disease indicators (body mass index [BMI] and A1C) in two low-income, predominantly African American (AA) neighborhoods in Detroit, Michigan. Sixty-nine adults (43 females, 26 males, mean age 46 years [y], standard deviation [SD] ​= ​15.9) completed a health survey, anthropometry, and finger stick blood tests. A1C was measured using A1CNow test strips, and CRP and TERT levels were measured using enzyme-linked immunosorbent assay (ELISA) with samples extracted from dried blood spots. We examined CRP (mean ​= ​4.9, SD ​= ​3.1), TERT (mean ​= ​32.5, SD ​= ​15.1), and A1C (mean ​= ​5.4, SD ​= ​1.0) by BMI category. We fitted restricted maximum likelihood regression models to evaluate associations between CRP, TERT, BMI, and A1C, after adjustment for demographics and inclusion of a random effect for the neighborhood. In this predominantly AA sample (91%, 63/69), 68% had levels of CRP (means ​= ​4.8 ​mg/L, SD ​= ​3.0 for AAs; 6.4 ​mg/L, SD ​= ​3.9 for all others) indicative of chronic inflammation (CRP greater than 3 ​mg/L). BMI was significantly associated with CRP (p ​= ​0.004) and TERT (p ​= ​0.026). TERT levels indicate that being overweight is associated with markers of chromosome remodeling, suggestive of chronic disease. CRP followed a similar trend with overweight individuals having higher inflammation and risk of chronic disease. Our findings warrant further exploration of additional factors that may influence CRP and TERT. Furthermore, examining populations in a more ethnically and/or economically diverse, yet still high proportion minority, sample will fill a knowledge gap in this understudied field.

Identification of mechanism of cancer-cell-specific reactivation of hTERT offers therapeutic opportunities for blocking telomerase specifically in human colorectal cancer

Transcriptional reactivation of hTERT is the limiting step in tumorigenesis. While mutations in hTERT promoter present in 19% of cancers are recognized as key drivers of hTERT reactivation, mechanisms by which wildtype hTERT (WT-hTERT) promoter is reactivated, in majority of human cancers, remain unknown. Using primary colorectal cancers (CRC) we identified Tert INTeracting region 2 (T-INT2), the critical chromatin region essential for reactivating WT-hTERT promoter in CRCs. Elevated β-catenin and JunD level in CRC facilitates chromatin interaction between hTERT promoter and T-INT2 that is necessary to turn on hTERTexpression. Pharmacological screens uncovered salinomycin, which inhibits JunD mediated hTERT-T-INT2 interaction that is required for the formation of a stable transcription complex on the hTERT promoter. Our results showed for the first time how known CRC alterations, such as APC, lead to WT-hTERT promoter reactivation during stepwise-tumorigenesis and provide a new perspective for developing cancer-specific drugs.

Research Progress on G-Quadruplexes in Human Telomeres and Human Telomerase Reverse Transcriptase (hTERT) Promoter

The upregulation telomerase activity is observed in over 85-90% of human cancers and provides an attractive target for cancer therapies. The high guanine content in the telomere DNA sequences and the hTERT promoter can form G-quadruplexes (G4s). Small molecules targeting G4s in telomeres and hTERT promoter could stabilize the G4s and inhibit hTERT expression and telomere extension. Several G4 ligands have shown inhibitory effects in cancer cells and xenograft mouse models, indicating these ligands have a potential for cancer therapies. The current review article describes the concept of the telomere, telomerase, and G4s. Moreover, the regulation of telomerase and G4s in telomeres and hTERT promoter is discussed as well. The summary of the small molecules targeting G4s in telomeric DNA sequences and the hTERT promoter will also be shown.

Emerging mechanisms of telomerase reactivation in cancer

Mutations in the promoter of human telomerase reverse transcriptase (hTERT) result in hyperactivation of hTERT. Notably, all mutations are G>A transitions, frequently found in a wide range of cancer types, and causally associated with cancer progression. Initially, the mutations were understood to reactivate hTERT by generating novel E26 transformation-specific (ETS) binding sites. Recent work reveals the role of DNA secondary structure G-quadruplexes, telomere binding factor(s), and chromatin looping in hTERT regulation. Here, we discuss these emerging findings in relation to the clinically significant promoter mutations to provide a broader understanding of the context-dependent outcomes that result in hTERT activation in normal and pathogenic conditions.