Alternative splicing is a developmental switch for hTERT expression.

Telomere length control is critical for cellular lifespan and tumor suppression. Telomerase is transiently activated in the inner cell mass of the developing blastocyst to reset telomere reserves. Its silencing upon differentiation leads to gradual telomere shortening in somatic cells. Here, we report that transcriptional regulation through cis-regulatory elements only partially accounts for telomerase activation in pluripotent cells. Instead, developmental control of telomerase is primarily driven by an alternative splicing event, centered around hTERT exon 2. Skipping of exon 2 triggers hTERT mRNA decay in differentiated cells, and conversely, its retention promotes telomerase accumulation in pluripotent cells. We identify SON as a regulator of exon 2 alternative splicing and report a patient carrying a SON mutation and suffering from insufficient telomerase and short telomeres. In summary, our study highlights a critical role for hTERT alternative splicing in the developmental regulation of telomerase and implicates defective splicing in telomere biology disorders.

DDB2 promotes melanoma cell growth by transcriptionally regulating the expression of KMT2A and predicts a poor prognosis.

Identification of potential key targets of melanoma, a fatal skin malignancy, is critical to the development of new cancer therapies. Lysine methyltransferase 2A (KMT2A) promotes melanoma growth by activating the human telomerase reverse transcriptase (hTERT) signaling pathway; however, the exact mechanism remains elusive. This study aimed to reveal new molecular targets that regulate KMT2A expression and melanoma growth. Using biotin-streptavidin-agarose pull-down and proteomics, we identified Damage-specific DNA-binding protein 2 (DDB2) as a KMT2A promoter-binding protein in melanoma cells and validated its role as a regulator of KMT2A/hTERT signaling. DDB2 knockdown inhibited the expression of KMT2A and hTERT and inhibited the growth of melanoma cells in vitro. Conversely, overexpression of DDB2 activated the expression of KMT2A and promoted the growth of melanoma cells. Additionally, we demonstrated that DDB2 expression was higher in tumor tissues of patients with melanoma than in corresponding normal tissues and was positively correlated with KMT2A expression. Kaplan-Meier analysis showed a poor prognosis in patients with high levels of DDB2 and KMT2A. Overall, our data suggest that DDB2 promotes melanoma cell growth through the transcriptional regulation of KMT2A expression and predicts poor prognosis. Therefore, targeting DDB2 may regulate the effects of KMT2A on melanoma growth and progression, providing a new potential therapeutic strategy for melanoma.

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.

Noncanonical functions of telomerase and telomeres in viruses-associated cancer.

The cause of cancer is attributed to the uncontrolled growth and proliferation of cells resulting from genetic changes and alterations in cell behavior, a phenomenon known as epigenetics. Telomeres, protective caps on the ends of chromosomes, regulate both cellular aging and cancer formation. In most cancers, telomerase is upregulated, with the telomerase reverse transcriptase (TERT) enzyme and telomerase RNA component (TERC) RNA element contributing to the maintenance of telomere length. Additionally, it is noteworthy that two viruses, human papillomavirus (HPV) and Epstein-Barr virus (EBV), utilize telomerase for their replication or persistence in infected cells. Also, TERT and TERC may play major roles in cancer not related to telomere biology. They are involved in the regulation of gene expression, signal transduction pathways, cellular metabolism, or even immune response modulation. Furthermore, the crosstalk between TERT, TERC, RNA-binding proteins, and microRNAs contributes to a greater extent to cancer biology. To understand the multifaceted roles played by TERT and TERC in cancer and viral life cycles, and then to develop effective therapeutic strategies against these diseases, are fundamental for this goal. By investigating deeply, the complicated mechanisms and relationships between TERT and TERC, scientists will open the doors to new therapies. In its analysis, the review emphasizes the significance of gaining insight into the multifaceted roles that TERT and TERC play in cancer pathogenesis, as well as their involvement in the viral life cycle for designing effective anticancer therapy approaches.

Human artificial chromosome carrying 3p21.3-p22.2 region suppresses hTERT transcription in oral cancer cells.

Telomerase is a ribonucleoprotein ribonucleic enzyme that elongates telomere repeat sequences at the ends of chromosomes and contributes to cellular immortalization. The catalytic component of telomerase, human telomerase reverse transcriptase (hTERT), has been observed to be reactivated in immortalized cells. Notably, most cancer cells have been found to have active hTERT mRNA transcription, resulting in continuous cell division, which is crucial for malignant transformation. Therefore, discovering mechanisms underlying the regulation of hTERT transcription is an attractive target for cancer-specific treatments.Loss of heterozygosity (LOH) of chromosome 3p21.3 has been frequently observed in human oral squamous cell carcinoma (OSCC). Moreover, we previously reported that HSC3 OSCC microcell hybrid clones with an introduced human chromosome 3 (HSC3#3) showed inhibition of hTERT transcription compared with the parental HSC3 cells. This study examined whether hTERT transcription regulators are present in the 3p21.3 region. We constructed a human artificial chromosome (HAC) vector (3p21.3-HAC) with only the 3p21.3-p22.2 region and performed functional analysis using the 3p21.3-HAC. HSC3 microcell hybrid clones with an introduced 3p21.3-HAC exhibited significant suppression of hTERT transcription, similar to the microcell hybrid clones with an intact chromosome 3. In contrast, HSC3 clones with truncated chromosome 3 with deletion of the 3p21.3 region (3delp21.3) showed no effect on hTERT expression levels. These results provide direct evidence that hTERT suppressor gene(s) were retained in the 3p21.3 region, suggesting that the presence of regulatory factors that control telomerase enzyme activity may be involved in the development of OSCC.

Safety and dose escalation of the targeted oncolytic adenovirus OBP-301 for refractory advanced liver cancer: Phase I clinical trial.

OBP-301 is an oncolytic adenovirus modified to replicate within cancer cells and lyse them. This open-label, non-comparative, phase I dose-escalation trial aimed to assess its safety and optimal dosage in 20 patients with advanced hepatocellular carcinoma. Good tolerance was shown with a maximum tolerated dose of 6 × 1012 viral particles. The most common treatment-emergent adverse events were influenza-like illness, pyrexia, fatigue, decreased platelet count, abdominal distension, and anemia. Cohorts 4 and 5 had approximately 50% higher levels of CD8+ T cells in the peripheral blood after injection. The best target response occurred in 14 patients, 4 of whom had progressive disease. Multiple intratumoral injections of OBP-301 were well tolerated in patients with advanced hepatocellular carcinoma. The stable disease rate for the injected tumors was greater than the overall response rate, even with no obvious tumor response. OBP-301 might have a greater impact on local response as histological examination revealed that the presence of OBP-301 was consistent with the necrotic area at the injection site. Increased infiltration of CD8+ T cells and <1% PD-L1 expression were observed in tumors after injection. Improved antitumor efficacy might be achieved in future studies via viral injection with volume adjustment and in combination with other immuno-therapeutics.

Polymorphic tandem DNA repeats activate the human telomerase reverse transcriptase gene.

Multiple independent sequence variants of the hTERT locus have been associated with telomere length and cancer risks in genome-wide association studies. Here, we identified an intronic variable number tandem repeat, VNTR2-1, as an enhancer-like element, which activated hTERT transcription in a cell in a chromatin-dependent manner. VNTR2-1, consisting of 42-bp repeats with an array of enhancer boxes, cooperated with the proximal promoter in the regulation of hTERT transcription by basic helix-loop-helix transcription factors and maintained hTERT expression during embryonic stem-cell differentiation. Genomic deletion of VNTR2-1 in MelJuSo melanoma cells markedly reduced hTERT transcription, leading to telomere shortening, cellular senescence, and impairment of xenograft tumor growth. Interestingly, VNTR2-1 lengths varied widely in human populations; hTERT alleles with shorter VNTR2-1 were underrepresented in African American centenarians, indicating its role in human aging. Therefore, this polymorphic element is likely a missing link in the telomerase regulatory network and a molecular basis for genetic diversities of telomere homeostasis and age-related disease susceptibilities.

TRIM28 is a transcriptional activator of the mutant TERT promoter in human bladder cancer.

Bladder cancer (BC) has a 70% telomerase reverse transcriptase (TERT or hTERT in humans) promoter mutation prevalence, commonly at -124 base pairs, and this is associated with increased hTERT expression and poor patient prognosis. We inserted a green fluorescent protein (GFP) tag in the mutant hTERT promoter allele to create BC cells expressing an hTERT-GFP fusion protein. These cells were used in a fluorescence-activated cell sorting-based pooled CRISPR-Cas9 Kinome knockout genetic screen to identify tripartite motif containing 28 (TRIM28) and TRIM24 as regulators of hTERT expression. TRIM28 activates, while TRIM24 suppresses, hTERT transcription from the mutated promoter allele. TRIM28 is recruited to the mutant promoter where it interacts with TRIM24, which inhibits its activity. Phosphorylation of TRIM28 through the mTOR complex 1 (mTORC1) releases it from TRIM24 and induces hTERT transcription. TRIM28 expression promotes in vitro and in vivo BC cell growth and stratifies BC patient outcome. mTORC1 inhibition with rapamycin analog Ridaforolimus suppresses TRIM28 phosphorylation, hTERT expression, and cell viability. This study may lead to hTERT-directed cancer therapies with reduced effects on normal progenitor cells.

Association of hTERT Gene Polymorphism and Colorectal Cancer (CRC) Risk in the Chinese Han Population.

The catalytic subunit telomerase reverse transcriptase (hTERT) is a prerequisite for malignant transformation of human cells. Colorectal cancer (CRC) is a common malignant tumor. The genetic association of hTERT gene rs2853669 and rs2736098 polymorphisms with CRC was surveyed in the Chinese population. Two hundreds patients with CRC and 200 healthy controls were taken for blood sample collection. Sanger sequencing was applied for genotyping. Multiple logistic regression analysis was performed, and odds ratio (OR) together with confidence interval (CI) were calculated to obtain the corresponding association power. Among CRC cases (49.50%), hTERT gene rs2736098 GA genotype carriers were more prevalent compared with the control group (41.00%, P = 0.035), which increased the risk of CRC by 1.576 times (95% CI, 1.031-2.409). Distribution of the rs2736098 genotypes was significantly associated with TNM stage, tumor differentiation, tumor size and lymph node metastasis (P < 0.05). The frequencies of hTERT gene rs2853669 polymorphism were not significantly different between CRC patients and healthy controls. Logistic regression analysis indicated that both body mass index (BMI) and hTERT gene rs2736098 polymorphism remained significantly correlated with CRC susceptibility. The frequencies of hTERT gene rs2853669 polymorphism did not differ significantly between CRC patients and control group (P > 0.05). The hTERT gene rs2736098 polymorphism was correlated with CRC risk in the Chinese Han population, and the GA genotype was a risk element for the onset of CRC.

hTERT Epigenetics Provides New Perspectives for Diagnosis and Evidence-Based Guidance of Chemotherapy in Cancer.

Strong epigenetic pan-cancer biomarkers are required to meet several current, urgent clinical needs and to further improve the present chemotherapeutic standard. We have concentrated on the investigation of epigenetic alteration of the hTERT gene, which is frequently epigenetically dysregulated in a number of cancers in specific developmental stages. Distinct DNA methylation profiles were identified in our data on early urothelial cancer. An efficient EpihTERT assay could be developed utilizing suitable combinations with sequence-dependent thermodynamic parameters to distinguish between differentially methylated states. We infer from this data set, the epigenetic context, and the related literature that a CpG-rich, 2800 bp region, a prominent CpG island, surrounding the transcription start of the hTERT gene is the crucial epigenetic zone for the development of a potent biomarker. In order to accurately describe this region, we have named it "Acheron" (Ἀχέρων). In Greek mythology, this is the river of woe and misery and the path to the underworld. Exploitation of the DNA methylation profiles focused on this region, e.g., idiolocal normalized Methylation Specific PCR (IDLN-MSP), opens up a wide range of new possibilities for diagnosis, determination of prognosis, follow-up, and detection of residual disease. It may also have broad implications for the choice of chemotherapy.

Telomerase activity and hTERT gene expression in patients with acute coronary syndrome and stable coronary artery disease.

BACKGROUND: In this study, we aimed to examine the telomerase activity and hTERT gene expression in patients with acute coronary syndrome (ACS) and those with stable coronary artery disease (SCAD) and compare the results to controls. Additionally, we compared overall mortality rates relative to the telomerase activity. METHODS: A total of 211 patients (78 ACS and 71 SCAD patients) were included in the study. The telomerase concentration was measured by ELISA and used to determine telomerase activity. The hTERT gene expression was determined by real-time PCR. RESULTS: The serum telomerase enzyme concentration was lower in ACS (36.61 ± 1.54) and SCAD (36.79 ± 1.57) when compared to the control group (37.03 ± 2.25). However, this difference did not reach statistical significance (p = 0.890). The hTERT gene expression acting in telomerase enzyme synthesis was 2.7-fold lower in ACS group (p = 0.070) and 2.2-fold lower in the SCAD group (p = 0.101) compared to the control group. Patients were followed for a median of 32 months (minimum: 0.1, maximum: 46.8). The serum telomerase concentrations in patients who died and those survived in the SCAD group (35.98 ± 2.02 vs 36.86 ± 1.52 ng/ml, respectively; p = 0.529) were similar to those in the ACS group (36.39 ± 1.08 vs 36.63 ± 1.60 ng/ml, respectively p = 0.993). CONCLUSIONS: In the current study, telomerase activity or hTERT expression was similar in patients with ACS, SCAD, and controls. Moreover, telomerase activity was not associated with all- cause mortality during the 32-month follow-up (Tab. 3, Fig. 1, Ref. 29).

Telomerase inhibition in malignant gliomas: a systematic review.

Glioblastoma (GBM) is the most frequent adult malignant brain tumour and despite different therapeutic efforts, the median overall survival still ranges from 14 to 18 months. Thus, new therapeutic strategies are urgently needed. However, the identification of cancer-specific targets is particularly challenging in GBM, due to the high heterogeneity of this tumour in terms of histopathological, molecular, genetic and epigenetic features. Telomerase reactivation is a hallmark of malignant glioma. An activating mutation of the hTERT gene, encoding for the active subunit of telomerase, is one of the molecular criteria to establish a diagnosis of GBM, IDH-wildtype, in the 2021 WHO classification of central nervous system tumours. Telomerase inhibition therefore represents, at least theoretically, a promising strategy for GBM therapy: pharmacological compounds, as well as direct gene expression modulation therapies, have been successfully employed in in vitro and in vivo settings. Unfortunately, the clinical applications of telomerase inhibition in GBM are currently scarce. The aim of the present systematic review is to provide an up-to-date report on the studies investigating telomerase inhibition as a therapeutic strategy for malignant glioma in order to foster the future translational and clinical research on this topic.

Lyon IARC Polyomavirus Displays Transforming Activities in Primary Human Cells.

Several studies reported the presence of a recently discovered polyomavirus (PyV), Lyon IARC PyV (LIPyV), in human and domestic animal specimens. LIPyV has some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV (MCPyV), respectively. In this study, we demonstrate that LIPyV early proteins immortalize human foreskin keratinocytes. LIPyV LT binds pRb, accordingly cell cycle checkpoints are altered in primary human fibroblasts and keratinocytes expressing LIPyV early genes. Mutation of the pRb binding site in LT strongly affected the ability of LIPyV ER to induced HFK immortalization. LIPyV LT also binds p53 and alters p53 functions activated by cellular stresses. Finally, LIPyV early proteins activate telomerase reverse transcriptase (hTERT) gene expression, via accumulation of the Sp1 transcription factor. Sp1 recruitment to the hTERT promoter is controlled by its phosphorylation, which is mediated by ERK1 and CDK2. Together, these data highlight the transforming properties of LIPyV in in vitro experimental models, supporting its possible oncogenic nature. IMPORTANCE Lyon IARC PyV is a recently discovered polyomavirus that shows some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV, respectively. Here, we show the capability of LIPyV to efficiently promote cellular transformation of primary human cells, suggesting a possible oncogenic role of this virus in domestic animals and/or humans. Our study identified a novel virus-mediated mechanism of activation of telomerase reverse transcriptase gene expression, via accumulation of the Sp1 transcription factor. In addition, because the persistence of infection is a key event in virus-mediated carcinogenesis, it will be important to determine whether LIPyV can deregulate immune-related pathways, similarly to the well-established oncogenic viruses.

Circulating tumor cells (CTCs) and hTERT gene expression in CTCs for radiotherapy effect with lung cancer.

BACKGROUND: Circulating tumor cells (CTCs) are important biological indicators of the lung cancer prognosis, and CTC counting and typing may provide helpful biological information for the diagnosis and treatment of lung cancer. METHODS: The CTC count in blood before and after radiotherapy was detected by the CanPatrol™ CTC analysis system, and the CTC subtypes and the expression of hTERT before and after radiotherapy were detected by multiple in situ hybridization. The CTC count was calculated as the number of cells per 5 mL of blood. RESULTS: The CTC positivity rate in patients with tumors before radiotherapy was 98.44%. Epithelial-mesenchymal CTCs (EMCTCs) were more common in patients with lung adenocarcinoma and squamous carcinoma than in patients with small cell lung cancer (P = 0.027). The total CTCs (TCTCs), EMCTCs, and mesenchymal CTCs (MCTCs) counts were significantly higher in patients with TNM stage III and IV tumors (P < 0.001, P = 0.005, and P < 0.001, respectively). The TCTCs and MCTCs counts were significantly higher in patients with an ECOG score of > 1 (P = 0.022 and P = 0.024, respectively). The TCTCs and EMCTCs counts before and after radiotherapy affected the overall response rate (ORR) (P < 0.05). TCTCs and ECTCs with positive hTERT expression were associated with the ORR of radiotherapy (P = 0.002 and P = 0.038, respectively), as were TCTCs with high hTERT expression (P = 0.012). ECOG score (P = 0.006) and post-radiation TCTCs count (P = 0.011) were independent factors for progression-free survival (PFS) and TNM stage (P = 0.054) and pre-radiation EMCTCs count (P = 0.009) were independent factors of overall survival (OS). CONCLUSION: This study showed a high rate of positive CTC detection in patients with lung cancer, and the number, subtype, and hTERT-positive expression of CTCs were closely related to patients' ORR, PFS, and OS with radiotherapy. EMCTCs, hTERT-positive expression of CTCs are expected to be important biological indicators for predicting radiotherapy efficacy and the prognosis in patients with lung cancer. These results may be useful in improving disease stratification for future clinical trials and may help in clinical decision-making.

Phosphorylation of hTERT at threonine 249 is a novel tumor biomarker of aggressive cancer with poor prognosis in multiple organs.

Recent evidence indicates that RNA-dependent RNA polymerase (RdRP) activity of human telomerase reverse transcriptase (hTERT) regulates expression of target genes and is directly involved in tumor formation in a telomere-independent manner. Non-canonical function of hTERT has been considered as a therapeutic target for cancer therapy. We have previously shown that hTERT phosphorylation at threonine 249 (p-hTERT), which promotes RdRP activity, is an indicator of an aggressive phenotype and poor prognosis in liver and pancreatic cancers, using two cohorts with small sample sizes with polyclonal p-hTERT antibody. To clarify the clinical relevance of p-hTERT, we developed a specific monoclonal antibody and determined the diagnostic and prognostic value of p-hTERT in cancer specimens using a large cohort. A monoclonal antibody for phosphorylated hTERT (p-hTERT) at threonine 249 was developed and validated. The antibody was used for the immunohistochemical staining of formalin-fixed, paraffin-embedded specimens from 1523 cases of lung, colon, stomach, pancreatic, liver, breast, and kidney cancers. We detected elevated p-hTERT expression levels in cases with a high mitotic activity, high pathological grade, and high nuclear pleomorphism. Elevated p-hTERT expression was an independent prognostic factor for lung, pancreatic, and liver cancers. Furthermore, p-hTERT expression was associated with immature and aggressive features, such as adenosquamous carcinoma (lung and pancreas), invasive type of cancer (lung), high serum alpha-fetoprotein level (liver), and triple-negative status (breast). In conclusion, RdRP activity indicated by p-hTERT expression predicts aggressive cancer phenotypes in various types of cancer. Thus, p-hTERT is a novel biomarker for the diagnosis of aggressive cancers with a poor prognosis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The effect of natural polyphenols Resveratrol, Gallic acid, and Kuromanin chloride on human telomerase reverse transcriptase (hTERT) expression in HepG2 hepatocellular carcinoma: role of SIRT1/Nrf2 signaling pathway and oxidative stress.

BACKGROUND: There is evidence that low doses or physiological concentrations of certain natural polyphenols enhance the activity of telomerase. However, the precise mechanism by which natural polyphenols regulate telomerase activity remains unclear. Recent research indicates that NF-E2 related factor 2 (Nrf2) and silent information regulator 1 (SIRT1) are involved in human telomerase reverse transcriptase (hTERT) regulation. Thus, in order to better comprehend the mechanism by which polyphenols regulate hTERT, the present study investigated the effects of the natural polyphenols Resveratrol, Gallic acid, and Kuromanin chloride on hTERT, Nrf2, and SIRT1 expression as well as oxidative stress in HepG2 hepatocellular carcinoma. METHODS: The trypan blue dye exclusion assay was used to assess cell viability. The level of mRNA for hTERT, Nrf2, and SIRT1 was then determined using real-time PCR. A spectrophotometric analysis was conducted to quantify oxidative stress markers. RESULTS: The results demonstrated that Resveratrol induces the expression of hTERT and the SIRT1/Nrf2 pathway in a dose-dependent manner. Gallic acid at concentrations of 10 and 20 µM also increased the expression of the hTERT and SIRT1/Nrf2 pathway. Furthermore, dose-dependent overexpression of hTERT and Nrf2 was induced by Kuromanin chloride at 10 and 20 µM. Moreover, we found that Resveratrol and Kuromanin chloride ameliorated oxidative stress, whereas Gallic acid exacerbated it. CONCLUSIONS: This study demonstrates that low doses of polyphenols (Resveratrol, Gallic acid, and Kuromanin chloride) upregulate the expression of the hTERT gene in the HepG2 hepatocellular carcinoma cell line, possibly via induction of the SIRT1/Nrf2 signaling pathway. Therefore, by targeting this pathway or hTERT, the anti-cancer effect of polyphenols can be enhanced.

Differential Expression of the hTERT Gene in Umbilical Cord-Derived Mesenchymal Stem Cells Cocultured with B Cell Precursor Leukemia Cell Microparticles or CD41+/CD61+ Platelet Microparticles.

Several investigations are being done to increase the short lifetime of mesenchymal stem cells (MSCs). One of the crucial genes involved in the immortalization of MSCs, hTERT (human telomerase reverse transcriptase), is activated in most publications using viral-based techniques. In this work, we investigated the use of platelet-derived (PMPs) and B cell precursor leukemia-derived microparticles as a nonviral method to trigger and compare the expression of the hTERT gene in MSCs. MSCs were extracted from the umbilical cord for the current investigation and identified using a flow cytometry approach and an inverted microscope. The Nalm-6 cell line and platelet concentrate were used to isolate microparticles (MPs). MSCs and MPs were cocultured for 14 days at 25-, 50-, and 100 µg/ml concentrations. qRT-PCR was used to research the expression of the hTERT gene. SPSS 26.0's t test was used to compare the outcomes. After coculture with platelet MPs, MSCs had higher levels of hTERT gene expression than the control group. In contrast, this gene's expression was concurrently decreased in MSCs exposed to MPs generated from Nalm-6. We demonstrated that following 14-day treatment, PMP significantly boosted the hTERT gene expression in MSCs, while the Nalm-6 MPs lowered the gene expression. However, additional studies are necessary due to the stability of hTERT gene expression and the immortalization of MSCs following exposure.

Immortalization Reversibility in the Context of Cell Therapy Biosafety.

Immortalization (genetically induced prevention of replicative senescence) is a promising approach to obtain cellular material for cell therapy or for bio-artificial organs aimed at overcoming the problem of donor material shortage. Immortalization is reversed before cells are used in vivo to allow cell differentiation into the mature phenotype and avoid tumorigenic effects of unlimited cell proliferation. However, there is no certainty that the process of de-immortalization is 100% effective and that it does not cause unwanted changes in the cell. In this review, we discuss various approaches to reversible immortalization, emphasizing their advantages and disadvantages in terms of biosafety. We describe the most promising approaches in improving the biosafety of reversibly immortalized cells: CRISPR/Cas9-mediated immortogene insertion, tamoxifen-mediated self-recombination, tools for selection of successfully immortalized cells, using a decellularized extracellular matrix, and ensuring post-transplant safety with the use of suicide genes. The last process may be used as an add-on for previously existing reversible immortalized cell lines.

Identification of h-TERT Promoter Mutations in Germline DNA from North Indian Lung Carcinoma Patients.

Lung cancer is a severe and the leading cause of cancer related deaths worldwide. The recurrent h-TERT promoter mutations have been implicated in various cancer types. Thus, the present study is extended to analyze h-TERT promoter mutations from the North Indian lung carcinoma patients. Total 20 histopathologically and clinically confirmed cases of lung cancer were enrolled in this study. The genomic DNA was extracted from venous blood and subjected to amplification using appropriate h-TERT promoter primers. Amplified PCR products were subjected for DNA Sanger sequencing for the identification of novel h-TERT mutations. Further, these identified h-TERT promoter mutations were analysed for the prediction of pathophysiological consequences using bioinformatics tools such as Tfsitescan and CIIDER. The average age of patients was 45 ± 8 years which was categorized in early onset of lung cancer with predominance of male patients by 5.6 fold. Interestingly, h-TERT promoter mutations were observed highly frequent in lung cancer. Identified mutations include c. G272A, c. T122A, c. C150A, c. 123 del C, c. C123T, c. G105A, c. 107 Ins A, c. 276 del C corresponding to -168 G>A, -18 T>A, -46 C>A, -19 del C, -19 C>T, -1 G>A, -3 Ins A, -172 del C respectively from the translation start site in the promoter of the telomerase reverse transcriptase gene which are the first time reported in germline genome from lung cancer. Strikingly, c. -18 T>A [C.T122A] was found the most prevalent variant with 75% frequency. Notwithstanding, other mutations viz c. -G168A [c. G272A] and c. -1 G>A [c. G105A] were found to be at 35% and 15% frequency respectively whilst the rest of the mutations were present at 10% and 5% frequency. Additionally, bioinformatics analysis revealed that these mutations can lead to either loss or gain of various transcription factor binding sites in the h-TERT promoter region. Henceforth, these mutations may play a pivotal role in h-TERT gene expression. Taken together, these identified novel promoter mutations may alter the epigenetics and subsequently various transcription factor binding sites which are of great functional significance. Thereby, it is plausible that these germline mutations may involve either as predisposing factor or direct participation in the pathophysiology of lung cancer through entangled molecular mechanisms.

Atypical Case of Highly Mutated h-TERT Promoter in Germline Genome from Buccal Mucosa Cancer.

Buccal mucosa cancer has an aggressive nature as it rapidly grows and penetrates with high recurrence rate. Strikingly, carcinoma of buccal mucosa is the most common cancer of oral cavity in India. Recently, telomerase and telomere biology have been implicated in the pathogenesis and progression in various cancers via regulation of telomere maintenance by telomerase expression which is controlled by telomerase reverse transcriptase (TERT) promoter. Strikingly, h-TERT promoter mutations have been incriminated in regulation of telomerase gene expression. Here, we present a 35 years old male with intense coughing, short breathlessness and fever since 15 days, was admitted to the pulmonary unit. He was a chronic smoker and gutka user. The cytopathological analysis of gastric aspirate revealed buccal mucosa carcinoma of IV stage. We identified h-TERT promoter mutations in isolated genomic DNA from whole blood using DNA sequencer. Genetic analysis disclosed that h-TERT promoter region was highly mutated in this patient. Identified mutations include C.-248 del G, C.-272 del G, C.-279 del G, C.-331 del G, C.-349 del G, C.-351 del C, C.-360 G > A, C.-362 T > A, C.-371 del T and C.-372 del T. Further, all identified mutations were subjected to predict the pathologic functional consequences using bioinformatics tools viz TFsitescan and CiiiDER which showed either loss or gain of transcription factors binding sites in h-TERT promoter. This is a unique case in which total 9 mutations were observed in h-TERT promoter in a single case. In conclusion, all together these mutations in h-TERT promoter may alter the epigenetics and subsequently the tenacity of binding transcription factors which are of functional significance.