DKC1 is a transcriptional target of GATA1 and drives upregulation of telomerase activity in normal human erythroblasts

Cancer Precursor Syndromes and Their Detection in the Head and Neck

This article explores the multifaceted landscape of oral cancer precursor syndromes. Hereditary disorders like dyskeratosis congenita and Fanconi anemia increase the risk of malignancy. Oral potentially malignant disorders, notably leukoplakia, are discussed as precursors influenced by genetic and immunologic facets. Molecular insights delve into genetic mutations, allelic imbalances, and immune modulation as key players in precancerous progression, suggesting potential therapeutic targets. The article navigates the controversial terrain of management strategies of leukoplakia, encompassing surgical resection, chemoprevention, and immune modulation, while emphasizing the ongoing challenges in developing effective, evidence-based preventive approaches.

Analyzing the role of ferroptosis in ribosome-related bone marrow failure disorders: From pathophysiology to potential pharmacological exploitation

Within the last decade, the scientific community has witnessed the importance of ferroptosis as a novel cascade of molecular events leading to cellular decisions of death distinct from apoptosis and other known forms of cell death. Notably, such non- apoptotic and iron-dependent regulated cell death has been found to be intricately linked to several physiological processes as well as to the pathogenesis of various diseases. To this end, recent data support the notion that a potential molecular connection between ferroptosis and inherited bone marrow failure (IBMF) in individuals with ribosomopathies may exist. In this review, we suggest that in ribosome-related IBMFs the identified mutations in ribosomal proteins lead to changes in the ribosome composition of the hematopoietic progenitors, changes that seem to affect ribosomal function, thus enhancing the expression of some mRNAs subgroups while reducing the expression of others. These events lead to an imbalance inside the cell as some molecular pathways are promoted while others are inhibited. This disturbance is accompanied by ROS production and lipid peroxidation, while an additional finding in most of them is iron accumulation. Once lipid peroxidation and iron accumulation are the two main characteristics of ferroptosis, it is possible that this mechanism plays a key role in the manifestation of IBMF in this type of disease. If this molecular mechanism is further confirmed, new pharmacological targets such as ferroptosis inhibitors that are already exploited for the treatment of other diseases, could be utilized to improve the treatment of ribosomopathies.

Molecular mechanisms underlying the regulation of tumour suppressor genes in lung cancer

Tumour suppressor genes play a cardinal role in the development of a large array of human cancers, including lung cancer, which is one of the most frequently diagnosed cancers worldwide. Therefore, extensive studies have been committed to deciphering the underlying mechanisms of alterations of tumour suppressor genes in governing tumourigenesis, as well as resistance to cancer therapies. In spite of the encouraging clinical outcomes demonstrated by lung cancer patients on initial treatment, the subsequent unresponsiveness to first-line treatments manifested by virtually all the patients is inherently a contentious issue. In light of the aforementioned concerns, this review compiles the current knowledge on the molecular mechanisms of some of the tumour suppressor genes implicated in lung cancer that are either frequently mutated and/or are located on the chromosomal arms having high LOH rates (1p, 3p, 9p, 10q, 13q, and 17p). Our study identifies specific genomic loci prone to LOH, revealing a recurrent pattern in lung cancer cases. These loci, including 3p14.2 (FHIT), 9p21.3 (p16INK4a), 10q23 (PTEN), 17p13 (TP53), exhibit a higher susceptibility to LOH due to environmental factors such as exposure to DNA-damaging agents (carcinogens in cigarette smoke) and genetic factors such as chromosomal instability, genetic mutations, DNA replication errors, and genetic predisposition. Furthermore, this review summarizes the current treatment landscape and advancements for lung cancers, including the challenges and endeavours to overcome it. This review envisages inspired researchers to embark on a journey of discovery to add to the list of what was known in hopes of prompting the development of effective therapeutic strategies for lung cancer.

Dyskerin and telomerase RNA component are sex-differentially associated with outcomes and Sunitinib response in patients with clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) displays sex-biased incidence, outcomes, molecular alterations and treatment efficacy; however, clinical managements are largely identical in male and female patients. Moreover, many biomarkers have been identified as predictors for ccRCC outcomes and response to therapeutic drugs, such as multitargeted tyrosine-kinase receptor (TKR) inhibitors, but little is known about their sex-specificity. Dyskerin (DKC1), encoded by the DKC1 gene within Xq28, is a telomerase co-factor stabilizing telomerase RNA component (TERC) and overexpressed in various cancers. Here, we determined whether DKC1 and/or TERC affect ccRCC sex-differentially.

METHODS

DKC1 and TERC expression in primary ccRCC tumors was assessed using RNA sequencing and qPCR. DKC1 association with molecular alterations and overall or progression-free survival (OS or PFS) was analyzed in the TCGA cohort of ccRCC. The IMmotion 151 and 150 ccRCC cohorts were analyzed to evaluate impacts of DKC1 and TERC on Sunitinib response and PFS.

RESULTS

DKC1 and TERC expression was significantly upregulated in ccRCC tumors. High DKC1 expression predicts shorter PFS independently in female but not male patients. Tumors in the female DKC1-high group exhibited more frequent alterations in PIK3CA, MYC and TP53 genes. Analyses of the IMmotion 151 ccRCC cohort treated with the TKR inhibitor Sunitinib showed that female patients in the DKC1-high group was significantly associated with lower response rates (P = 0.021) accompanied by markedly shortened PFS (6.1 vs 14.2 months, P = 0.004). DKC1 and TERC expression correlated positively with each other, and higher TERC expression predicted poor Sunitinib response (P = 0.031) and shorter PFS (P = 0.004), too. However, DKC1 rather than TERC acted as an independent predictor (P < 0.001, HR = 2.0, 95% CI 1.480-2.704). In male patients, DKC1 expression was associated with neither Sunitinib response (P = 0.131) nor PFS (P = 0.184), while higher TERC levels did not predict response rates. Similar results were obtained from the analysis of the Sunitinib-treated IMmotion 150 ccRCC patients.

CONCLUSIONS

DKC1 serves as an independent female-specific predictor for survival and Sunitinib efficacy in ccRCC, which contribute to better understanding of the sex-biased ccRCC pathogenesis and improve personalized interventions of ccRCC.

miRNA326-5p Targets DKC1 Gene to Regulate Apoptosis-Related Proteins and Intervene in the Development of Neuroblastoma

Objective

To study the effect of congenital dyskeratosis 1 (DKC1) on neuroblastoma and its regulation mechanism.

Methods

The expression of DKC1 in neuroblastoma was analyzed by TCGA database and molecular assay. NB cells were transfected with siDKC1 to observe the effects of DKC1 on proliferation, cloning, metastasis, and invasion, and apoptosis and apoptosis-related proteins. The tumor-bearing mouse model was constructed, shDKC1 was transfected to observe the tumor growth and tumor tissue changes, and the expression of DKC1 and Ki-67 was detected. Screening and identification of miRNA326-5p targeting DKC1. NB cells were treated with miRNA326-5p mimic or inhibitors to detect the expression of DKC1. NB cells were transfected with miRNA326-5p and DKC1 mimics to detect cell proliferation, apoptosis, and apoptotic protein expression.

Results

DKC1 was highly expressed in NB cells and tissues. The activity, proliferation, invasion, and migration of NB cells were significantly decreased by DKC1 gene knockout, while apoptosis was significantly increased. The expression level of B-cell lymphoma-2 in shDKC1 group was significantly lower than that of the control group, while the expression level of BAK, BAX, and caspase-3 was significantly higher than that of the control group. The results of experiments on tumor-bearing mice were consistent with the above results. The results of miRNA assay showed that miRNA326-5p could bind DKC1 mRNA to inhibit the protein expression, thereby inhibiting the proliferation of NB cells, promoting their apoptosis, and regulating the expression of apoptotic proteins.

Conclusion

miRNA326-5p targeting DKC1 mRNA regulates apoptosis-related proteins to inhibit neuroblastoma proliferation and promote the apoptotic process.

Insights on the potential oncogenic impact of long non-coding RNA nicotinamide nucleotide transhydrogenase antisense RNA 1 in different cancer types; integrating pathway(s) and clinical outcome(s) association

Long non-coding RNAs (lncRNAs) are becoming more prevalent in the cancer field arena, with functional roles in both oncogenic and onco-suppressive pathways. Despite their widespread aberrant expression in a range of human malignancies, the biological activities of the ncRNAs majority are unknown. All showed the involvement of the lncRNA nicotinamide nucleotide transhydrogenase antisense RNA 1 (NNT-AS1). Since NNT-AS1 influences cellular proliferation, invasion, migration, apoptosis, and metastasis, this lncRNA appears to be linked to deregulating the normal cellular processes driving malignancy. This was observed in breast cancer (BC), gastric cancer (GC), colorectal cancer (CRC), epithelial ovarian cancer (EOC), and hepatocellular carcinoma (HCC). The current narrative non-systematic review will discuss "the significance of lncRNAs in cancer", as well as "lncRNAs future potential application(s) as diagnostic or predictive biomarkers", therefore, comprising an opportunity as treatment target(s). The review will have a special emphasis on lncRNA NNT-AS1.

PUS1 is a novel biomarker for predicting poor outcomes and triple-negative status in breast cancer

Breast cancer patients' outcomes have improved dramatically in recent years, but relapses and poor prognosis remain common due to its aggressiveness and heterogeneity. The development of reliable biomarkers is still needed for predicting prognosis and treatment effectiveness. Recently, a growing body of research suggests that pseudouridine synthases contribute to the development of many cancers, but their contribution to breast cancer remains largely unknown. Using an integrative analysis, we selected pseudouridine synthase1(PUS1) as the candidate biomarker. A tissue microarray of 131 breast cancer patients was then utilized to determine the clinical significance and prognostic value of PUS1. RNA sequencing analysis was conducted to identify downstream genes that differ between control and PUS1 knockdown cells. The effect of PUS1 on phenotypes of cells was assessed using cell proliferation, colony formation, and transwell invasion assays. We found that breast tumors overexpressed PUS1 compared with paired normal tissues. PUS1 expression was positively correlated with triple-negative breast cancer (TNBC) status (P= 0.020) and tumor grade (P <0.0001), but not with age (P= 0.736), tumor size (P= 0.608), lymph node (P= 0.742), oestrogen receptor (ER) (P= 0.162), progesterone receptor (PR) (P= 0.901), human epidermal growth factor receptor 2 (HER2) (P= 0.608) or tumor stage (P= 0.411). Comparatively, patients with high PUS1 levels had shorter overall survival time (P=0.0001) and relapse-free survival time (P = 0.0093). A univariate and multivariate survival analysis suggested that the overall survival of patients was independently influenced by the PUS1 score (Univariate Cox P <0.0001, HR=5.176, 95% CI =2.420-11.07; Multivariate Cox P = 0.001, HR = 5.291, 95% CI =1.893-14.78). RNA sequencing data revealed the PUS1 knockdown significantly affects a series of cancer related biological process such as regulation of cell proliferation and cell migration, as well as KEGG pathways including Mitophagy and PI3K-Akt signaling. In vitro, knockdown of PUS1 significantly suppressed the proliferation and colony formation abilities of MDA-MB-231 cells and BT-549 cells. Additionally, the ability of tumor cells to invade was remarkably attenuated in low PUS1 expression groups compared with the corresponding control groups. Our results suggested that PUS1 is a novel biomarker that predicts poor outcomes in patients with breast cancer and may prove to be a promising treatment target.

Thyroid carcinoma-featured telomerase activation and telomere maintenance: Biology and translational/clinical significance

BACKGROUND

Telomerase is a ribonucleoprotein complex consisting of a catalytic component telomerase reverse transcriptase (TERT), internal RNA template and other co-factors, and its essential function is to synthesize telomeric DNA, repetitive TTAGGG sequences at the termini of linear chromosomes. Telomerase is silent in normal human follicular thyroid cells, primarily due to the TERT gene being tightly repressed. During the development and progression of thyroid carcinomas (TCs), TERT induction and telomerase activation is in general required to maintain telomere length, thereby conferring TC cells with immortal and aggressive phenotypes.

METHODS

The genomic alterations of the TERT loci including TERT promoter's gain-of-function mutations, copy number gain, fusion and rearrangements, have recently been identified in TCs as mechanisms to induce TERT expression and to activate telomerase. Importantly, numerous studies have consistently shown that TERT promoter mutations and TERT expression occur in all TC subtypes, and are robustly associated with TC malignancy, aggressiveness, treatment failure and poor outcomes. Therefore, the assessment of TERT promoter mutations and TERT expression is highly valuable in TC diagnostics, prognosis, treatment decision, and follow-up design. In addition, the TERT promoter is frequently hypermethylated in TC cells and tumors, which is required to activate TERT transcription and telomerase. Dysregulation of other components in the telomerase complex similarly upregulate telomerase. Moreover, shortened telomeres lead to altered gene expression and metabolism, thereby actively promoting TC aggressiveness. Here we summarize recent findings in TCs to provide the landscape of TC-featured telomere/telomerase biology and discuss underlying implications in TC precision medicine.

CONCLUSION

Mechanistic insights into telomerase activation and TERT induction in TCs are important both biologically and clinically. The TERT gene aberration and expression-based molecular classification of TCs is proposed, and for such a purpose, the standardization of the assay and evaluation system is required. Moreover, the TERT-based system and 2022 WHO TC classification may be combined to improve TC care.

Intron retention by a novel intronic mutation in DKC1 gene caused recurrent still birth and early death in a Chinese family

Background

DKC1, the dyskerin encoding gene, functions in telomerase activity and telomere maintenance. DKC1 mutations cause a multisystem disease, dyskeratosis congenita (DC), which is associated with immunodeficiency and bone marrow failure.

Methods

In this research, we reported a novel intronic mutation of DKC1 causing dyskerin functional loss in a Chinese family. Whole exome sequence (WES) of the proband and validation by sanger sequencing help us identify a pathogenic DKC1 mutation. Minigene splicing assays were performed to evaluate functional change of DKC1.

Results

A pathogenic DKC1 intronic mutation(c.84 + 7A > G) was identified in the proband, which was inherited from heterozygous mother and not reported before. We detected the novel transcript with a 7 bp intron retention through minigene splicing assay. The newly spliced transcript is so short that would be degraded by nonsense‐mediated mRNA decay in vitro and we infer that the novel DKC1 mutation would influences normal physiological function of dyskerin.

Conclusions

Our study identified a novel intronic mutation, which expands the spectrum of pathogenic DKC1 gene mutations and can be used in molecular diagnosis. The mutant allele was transmitted to the next generation with high frequency in the family and causes still birth or early death.

Dyskerin: an essential pseudouridine synthase with multifaceted roles in ribosome biogenesis, splicing, and telomere maintenance

Dyskerin and its homologs are ancient and conserved enzymes that catalyze the most common post-transcriptional modification found in cells, pseudouridylation. The resulting pseudouridines provide stability to RNA molecules and regulate ribosome biogenesis and splicing events. Dyskerin does not act independently-it is the core component of a protein heterotetramer, which associates with RNAs that contain the H/ACA motif. The variety of H/ACA RNAs that guide the function of this ribonucleoprotein (RNP) complex highlights the diversity of cellular processes in which dyskerin participates. When associated with small nucleolar (sno) RNAs, it regulates ribosomal (r) RNAs and ribosome biogenesis. By interacting with small Cajal body (sca) RNAs, it targets small nuclear (sn) RNAs to regulate pre-mRNA splicing. As a component of the telomerase holoenzyme, dyskerin binds to the telomerase RNA to modulate telomere maintenance. In a disease context, dyskerin malfunction can result in multiple detrimental phenotypes. Mutations in DKC1, the gene that encodes dyskerin, cause the premature aging syndrome X-linked dyskeratosis congenita (X-DC), a still incurable disorder that typically leads to bone marrow failure. In this review, we present the classical and most recent findings on this essential protein, discussing the evolutionary, structural, and functional aspects of dyskerin and the H/ACA RNP. The latest research underscores the role that dyskerin plays in the regulation of gene expression, translation efficiency, and telomere maintenance, along with the impacts that defective dyskerin has on aging, cell proliferation, haematopoietic potential, and cancer.

Dynamic changes in RNA-protein interactions and RNA secondary structure in mammalian erythropoiesis

Two features of eukaryotic RNA molecules that regulate their post-transcriptional fates are RNA secondary structure and RNA-binding protein (RBP) interaction sites. However, a comprehensive global overview of the dynamic nature of these sequence features during erythropoiesis has never been obtained. Here, we use our ribonuclease-mediated structure and RBP-binding site mapping approach to reveal the global landscape of RNA secondary structure and RBP-RNA interaction sites and the dynamics of these features during this important developmental process. We identify dynamic patterns of RNA secondary structure and RBP binding throughout the process and determine a set of corresponding protein-bound sequence motifs along with their dynamic structural and RBP-binding contexts. Finally, using these dynamically bound sequences, we identify a number of RBPs that have known and putative key functions in post-transcriptional regulation during mammalian erythropoiesis. In total, this global analysis reveals new post-transcriptional regulators of mammalian blood cell development.

Telomere-related Markers for Cancer

Telomeres are structurally nucleoprotein complexes at termini of linear chromosomes and essential to chromosome stability/integrity. In normal human cells, telomere length erodes progressively with each round of cell divisions, which serves as an important barrier to uncontrolled proliferation and malignant transformation. In sharp contrast, telomere maintenance is a key feature of human malignant cells and required for their infinite proliferation and maintenance of other cancer hallmarks as well. Thus, a telomere-based anti-cancer strategy has long been suggested. However, clinically efficient and specific drugs targeting cancer telomere-maintenance have still been in their infancy thus far. To achieve this goal, it is highly necessary to elucidate how exactly cancer cells maintain functional telomeres. In the last two decades, numerous studies have provided profound mechanistic insights, and the identified mechanisms include the aberrant activation of telomerase or the alternative lengthening of telomere pathway responsible for telomere elongation, dysregulation and mutation of telomere-associated factors, and other telomere homeostasis-related signaling nodes. In the present review, these various strategies employed by malignant cells to regulate their telomere length, structure and function have been summarized, and potential implications of these findings in the rational development of telomere-based cancer therapy and other clinical applications for precision oncology have been discussed.

Post-transcriptional control of cellular differentiation by the RNA exosome complex

Given the complexity of intracellular RNA ensembles and vast phenotypic remodeling intrinsic to cellular differentiation, it is instructive to consider the role of RNA regulatory machinery in controlling differentiation. Dynamic post-transcriptional regulation of protein-coding and non-coding transcripts is vital for establishing and maintaining proteomes that enable or oppose differentiation. By contrast to extensively studied transcriptional mechanisms governing differentiation, many questions remain unanswered regarding the involvement of post-transcriptional mechanisms. Through its catalytic activity to selectively process or degrade RNAs, the RNA exosome complex dictates the levels of RNAs comprising multiple RNA classes, thereby regulating chromatin structure, gene expression and differentiation. Although the RNA exosome would be expected to control diverse biological processes, studies to elucidate its biological functions and how it integrates into, or functions in parallel with, cell type-specific transcriptional mechanisms are in their infancy. Mechanistic analyses have demonstrated that the RNA exosome confers expression of a differentiation regulatory receptor tyrosine kinase, downregulates the telomerase RNA component TERC, confers genomic stability and promotes DNA repair, which have considerable physiological and pathological implications. In this review, we address how a broadly operational RNA regulatory complex interfaces with cell type-specific machinery to control cellular differentiation.

Nonsense Suppression Therapy: New Hypothesis for the Treatment of Inherited Bone Marrow Failure Syndromes

Inherited bone marrow failure syndromes (IBMFS) are a group of cancer-prone genetic diseases characterized by hypocellular bone marrow with impairment in one or more hematopoietic lineages. The pathogenesis of IBMFS involves mutations in several genes which encode for proteins involved in DNA repair, telomere biology and ribosome biogenesis. The classical IBMFS include Shwachman–Diamond syndrome (SDS), Diamond–Blackfan anemia (DBA), Fanconi anemia (FA), dyskeratosis congenita (DC), and severe congenital neutropenia (SCN). IBMFS are associated with high risk of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumors. Unfortunately, no specific pharmacological therapies have been highly effective for IBMFS. Hematopoietic stem cell transplantation provides a cure for aplastic or myeloid neoplastic complications. However, it does not affect the risk of solid tumors. Since approximately 28% of FA, 24% of SCN, 21% of DBA, 20% of SDS, and 17% of DC patients harbor nonsense mutations in the respective IBMFS-related genes, we discuss the use of the nonsense suppression therapy in these diseases. We recently described the beneficial effect of ataluren, a nonsense suppressor drug, in SDS bone marrow hematopoietic cells ex vivo. A similar approach could be therefore designed for treating other IBMFS. In this review we explain in detail the new generation of nonsense suppressor molecules and their mechanistic roles. Furthermore, we will discuss strengths and limitations of these molecules which are emerging from preclinical and clinical studies. Finally we discuss the state-of-the-art of preclinical and clinical therapeutic studies carried out for IBMFS.

LncRNA MEG3 inhibits non-small cell lung cancer via interaction with DKC1 protein

Long non-coding RNA (lncRNA) MEG3 is a key biomarker and therapeutic target in lung cancer; however, its underlying molecular mechanism in lung cancer progression remains unclear. The present study demonstrated a novel regulatory axis in lung cancer, lncRNA MEG3/dyskeratosis congenita 1 (DKC1), and further investigated the effects and molecular mechanism of lncRNA MEG3/DKC1 in lung cancer. RT-qPCR and western blot analysis were performed to determine gene and protein expression levels. The RNA immunoprecipitation assay was performed to verify binding between lncRNA MEG3 and DKC1. Flow cytometry analysis was performed to assess cell apoptosis, while the Cell Counting Kit-8 assay was performed to determine cell viability. Transwell and wound healing assays were performed to assess cell invasion and migration, respectively. Telomerase activity was measured using the quantitative TeloTAGGG Telomerase PCR-ELISA kit. The results demonstrated that lncRNA MEG3 was downregulated, while its binding protein, DKC1, was upregulated in lung cancer cells. Furthermore, lncRNA MEG3 inhibited cell proliferation, migration, invasion and telomerase activity in A549 cells by downregulating DKC1. lncRNA MEG3 inhibited non-small cell lung cancer progression by inhibiting telomere function, cell proliferation, telomerase activity, cell migration and invasion via regulation of the DKC1 protein expression. LncRNA MEG3/DKC1 was identified as a novel dual-directional regulatory axis in the present study, acting as a promising target for the treatment of lung cancer.