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Clinical and Translational Medicine Jun 2024Sporadic parathyroid adenoma (PA) is the most common cause of hyperparathyroidism, yet the mechanisms involved in its pathogenesis remain incompletely understood.
BACKGROUND
Sporadic parathyroid adenoma (PA) is the most common cause of hyperparathyroidism, yet the mechanisms involved in its pathogenesis remain incompletely understood.
METHODS
Surgically removed PA samples, along with normal parathyroid gland (PG) tissues that were incidentally dissected during total thyroidectomy, were analysed using single-cell RNA-sequencing with the 10× Genomics Chromium Droplet platform and Cell Ranger software. Gene set variation analysis was conducted to characterise hallmark pathway gene signatures, and single-cell regulatory network inference and clustering were utilised to analyse transcription factor regulons. Immunohistochemistry and immunofluorescence were performed to validate cellular components of PA tissues. siRNA knockdown and gene overexpression, alongside quantitative polymerase chain reaction, Western blotting and cell proliferation assays, were conducted for functional investigations.
RESULTS
There was a pervasive increase in gene transcription in PA cells (PACs) compared with PG cells. This is associated with high expression of histone-lysine N-methyltransferase 2A (KMT2A). High KMT2A levels potentially contribute to promoting PAC proliferation through upregulation of the proto-oncogene CCND2, which is mediated by the transcription factors signal transducer and activator of transcription 3 (STAT3) and GATA binding protein 3 (GATA3). PA tissues are heavily infiltrated with myeloid cells, while fibroblasts, endothelial cells and macrophages in PA tissues are commonly enriched with proinflammatory gene signatures relative to their counterparts in PG tissues.
CONCLUSIONS
We revealed the previously underappreciated involvement of the KMT2A‒STAT3/GATA3‒CCND2 axis and chronic inflammation in the pathogenesis of PA. These findings underscore the therapeutic promise of KMT2A inhibition and anti-inflammatory strategies, highlighting the need for future investigations to translate these molecular insights into practical applications.
HIGHLIGHTS
Single-cell RNA-sequencing reveals a transcriptome catalogue comparing sporadic parathyroid adenomas (PAs) with normal parathyroid glands. PA cells show a pervasive increase in gene expression linked to KMT2A upregulation. KMT2A-mediated STAT3 and GATA3 upregulation is key to promoting PA cell proliferation via cyclin D2. PAs exhibit a proinflammatory microenvironment, suggesting a potential role of chronic inflammation in PA pathogenesis.
Topics: Humans; Parathyroid Neoplasms; Adenoma; Inflammation; Histone-Lysine N-Methyltransferase; Myeloid-Lymphoid Leukemia Protein; Proto-Oncogene Mas; Cell Proliferation
PubMed: 38888967
DOI: 10.1002/ctm2.1734 -
Cancer Science Jun 2024Multiple epigenetic regulatory mechanisms exert critical roles in tumor development, and understanding the interactions and impact of diverse epigenetic modifications on...
Multiple epigenetic regulatory mechanisms exert critical roles in tumor development, and understanding the interactions and impact of diverse epigenetic modifications on gene expression in cancer is crucial for the development of precision medicine. We found that methyltransferase-like 14 (METTL14) was significantly downregulated in non-small-cell lung cancer (NSCLC) tissues. Functional experiments demonstrated that overexpression of METTL14 inhibited the proliferation and migration of NSCLC cells both in vivo and in vitro, and the colorimetric mA quantification assay also showed that knockdown of METTL14 notably reduced global mA modification levels in NSCLC cells. By using the methylated-RNA immunoprecipitation-qPCR and dual-luciferase reporter assays, we verified that long noncoding RNA LINC02747 was a target of METTL14 and was regulated by METTL14-mediated mA modification, and silencing LINC02747 inhibited the malignant progression of NSCLC by modulating the PI3K/Akt and CDK4/Cyclin D1 signaling pathway. Further studies revealed that overexpression of METTL14 promoted mA methylation and accelerated the decay of LINC02747 mRNA via increased recognition of the "GAACU" binding site by YTHDC2. Additionally, histone demethylase lysine-specific histone demethylase 5B (KDM5B) mediated the demethylation of histone H3 lysine 4 tri-methylation (H3K4me3) in the METTL14 promoter region and repressed its transcription. In summary, KDM5B downregulated METTL14 expression at the transcriptional level in a H3K4me3-dependent manner, while METTL14 modulated LINC02747 expression via mA modification. Our results demonstrate a synergy of multiple mechanisms in regulating the malignant phenotype of NSCLC, revealing the complex regulation involved in the occurrence and development of cancer.
PubMed: 38888105
DOI: 10.1111/cas.16254 -
CNS Neuroscience & Therapeutics Jun 2024Phenylethanolamine N-methyltransferase (PNMT)-expressing neurons in the nucleus tractus solitarii (NTS) contribute to the regulation of autonomic functions. However, the...
OBJECTIVE
Phenylethanolamine N-methyltransferase (PNMT)-expressing neurons in the nucleus tractus solitarii (NTS) contribute to the regulation of autonomic functions. However, the neural circuits linking these neurons to other brain regions remain unclear. This study aims to investigate the connectivity mechanisms of the PNMT-expressing neurons in the NTS (NTS neurons).
METHODS
The methodologies employed in this study included a modified rabies virus-based retrograde neural tracing technique, conventional viral anterograde tracing, and immunohistochemical staining procedures.
RESULTS
A total of 43 upstream nuclei projecting to NTS neurons were identified, spanning several key brain regions including the medulla oblongata, pons, midbrain, cerebellum, diencephalon, and telencephalon. Notably, dense projections to the NTS neurons were observed from the central amygdaloid nucleus, paraventricular nucleus of the hypothalamus, area postrema, and the gigantocellular reticular nucleus. In contrast, the ventrolateral medulla, lateral parabrachial nucleus, and lateral hypothalamic area were identified as the primary destinations for axon terminals originating from NTS neurons. Additionally, reciprocal projections were evident among 21 nuclei, primarily situated within the medulla oblongata.
CONCLUSION
Our research findings demonstrate that NTS neurons form extensive connections with numerous nuclei, emphasizing their essential role in the homeostatic regulation of vital autonomic functions.
Topics: Animals; Phenylethanolamine N-Methyltransferase; Solitary Nucleus; Neurons; Male; Efferent Pathways; Afferent Pathways; Rats, Sprague-Dawley; Brain Mapping; Rats
PubMed: 38887205
DOI: 10.1111/cns.14808 -
Molecular Medicine (Cambridge, Mass.) Jun 2024Glioma is the most common malignant tumor of the central nervous system, with EZH2 playing a crucial regulatory role. This study further explores the abnormal expression...
Glioma is the most common malignant tumor of the central nervous system, with EZH2 playing a crucial regulatory role. This study further explores the abnormal expression of EZH2 and its mechanisms in regulating glioma progression. Additionally, it was found that IHMT-337 can potentially be a therapeutic agent for glioma. The prognosis, expression, and localization of EZH2 were determined using bioinformatics, IHC staining, Western blot (WB) analysis, and immunofluorescence (IF) localization. The effects of EZH2 on cell function were assessed using CCK-8 assays, Transwell assays, and wound healing assays. Public databases and RT-qPCR were utilized to identify downstream targets. The mechanisms regulating these downstream targets were elucidated using MS-PCR and WB analysis. The efficacy of IHMT-337 was demonstrated through IC50 measurements, WB analysis, and RT-qPCR. The effects of IHMT-337 on glioma cells in vitro were evaluated using Transwell assays, EdU incorporation assays, and flow cytometry. The potential of IHMT-337 as a treatment for glioma was assessed using a blood-brain barrier (BBB) model and an orthotopic glioma model. Our research confirms significantly elevated EZH2 expression in gliomas, correlating with patient prognosis. EZH2 facilitates glioma proliferation, migration, and invasion alongside promoting SLC12A5 DNA methylation. By regulating SLC12A5 expression, EZH2 activates the WNK1-OSR1-NKCC1 pathway, enhancing its interaction with ERM to promote glioma migration. IHMT-337 targets EZH2 in vitro to inhibit WNK1 activation, thereby suppressing glioma cell migration. Additionally, it inhibits cell proliferation and arrests the cell cycle. IHMT-337 has the potential to cross the BBB and has successfully inhibited glioma progression in vivo. This study expands our understanding of the EZH2-SLC12A5 axis in gliomas, laying a new foundation for the clinical translation of IHMT-337 and offering new insights for precision glioma therapy.
Topics: Glioma; Enhancer of Zeste Homolog 2 Protein; Humans; Animals; Cell Line, Tumor; Mice; Cell Proliferation; Brain Neoplasms; Gene Expression Regulation, Neoplastic; Cell Movement; Signal Transduction; Xenograft Model Antitumor Assays; Prognosis
PubMed: 38886655
DOI: 10.1186/s10020-024-00857-0 -
Nature Communications Jun 2024Dysregulated epigenetic states are a hallmark of cancer and often arise from genetic alterations in epigenetic regulators. This includes missense mutations in histones,...
Dysregulated epigenetic states are a hallmark of cancer and often arise from genetic alterations in epigenetic regulators. This includes missense mutations in histones, which, together with associated DNA, form nucleosome core particles. However, the oncogenic mechanisms of most histone mutations are unknown. Here, we demonstrate that cancer-associated histone mutations at arginines in the histone H3 N-terminal tail disrupt repressive chromatin domains, alter gene regulation, and dysregulate differentiation. We find that histone H3R2C and R26C mutants reduce transcriptionally repressive H3K27me3. While H3K27me3 depletion in cells expressing these mutants is exclusively observed on the minor fraction of histone tails harboring the mutations, the same mutants recurrently disrupt broad H3K27me3 domains in the chromatin context, including near developmentally regulated promoters. H3K27me3 loss leads to de-repression of differentiation pathways, with concordant effects between H3R2 and H3R26 mutants despite different proximity to the PRC2 substrate, H3K27. Functionally, H3R26C-expressing mesenchymal progenitor cells and murine embryonic stem cell-derived teratomas demonstrate impaired differentiation. Collectively, these data show that cancer-associated H3 N-terminal arginine mutations reduce PRC2 activity and disrupt chromatin-dependent developmental functions, a cancer-relevant phenotype.
Topics: Histones; Cell Differentiation; Arginine; Animals; Humans; Mice; Polycomb Repressive Complex 2; Neoplasms; Mutation; Chromatin; Epigenesis, Genetic; Mesenchymal Stem Cells; Cell Line, Tumor
PubMed: 38886411
DOI: 10.1038/s41467-024-49486-5 -
Discover Oncology Jun 2024Lung metastases are the primary cause of death for osteosarcoma (OS) patients. We recently validated interleukin-11 receptor α (IL-11Rα) as a molecular target for the...
Lung metastases are the primary cause of death for osteosarcoma (OS) patients. We recently validated interleukin-11 receptor α (IL-11Rα) as a molecular target for the inhibition of OS lung metastases. Since there is no clinically approved antibody against this receptor, we sought to identify downstream targets that mediate the effects of IL-11Rα signaling. We used shRNA to deplete IL-11Rα from OS cells; as a complementary approach, we added IL-11 exogenously to OS cells. The resulting changes in gene expression identified EZH2 as a downstream candidate. This was confirmed by knockdown of IL-11Rα in OS cells, which led to increased expression of genes repressed by histone methyltransferase EZH2, including members of the WNT pathway, a known target pathway of EZH2. Exogenous IL-11 increased the global levels of histone H3 lysine 27 trimethylation, evidence of EZH2 activation. Treatment with the EZH2 inhibitor GSK126 significantly reduced in vitro proliferation and increased cell-cycle arrest and apoptosis, which were partially mediated through the WNT pathway. In vivo, treatment of an orthotopic nude mouse model of OS with GSK126 inhibited lung metastatic growth and prolonged survival. In addition, significantly shorter recurrence-free survival was seen in OS patients with high levels of EZH2 in their primary tumors (P < .05). This suggests that IL-11Rα promotes OS lung metastasis via activation of EZH2. Thus, blocking EZH2 activity may be an effective strategy for inhibiting OS lung metastasis and improving prognosis.
PubMed: 38886296
DOI: 10.1007/s12672-024-01056-3 -
Journal of Thoracic Disease May 2024The significant progress has been made in targeted therapy for lung adenocarcinoma (LUAD) in the past decade. Only few targeted therapeutics have yet been approved for...
BACKGROUND
The significant progress has been made in targeted therapy for lung adenocarcinoma (LUAD) in the past decade. Only few targeted therapeutics have yet been approved for the treatment of lung squamous cell carcinoma (LUSC). Several higher frequency of gene alterations are identified as potentially actionable in LUSC. Our work aimed to explore the complex interplay of multiple genetic alterations and pathways contributing to the pathogenesis of LUSC, with a very low frequency of a single driver molecular alterations to develop more effective therapeutic strategies in the future.
METHODS
We retrospectively analyzed the targeted next-generation sequencing (NGS) data (approximately 600 genes) of 335 patients initially diagnosed with non-small cell lung cancer (NSCLC) at our institution between January 2019 and March 2023 and explored the somatic genome alteration difference between LUSC and LUAD.
RESULTS
We analyzed that the presence of loss-of-function (LoF) mutations (nonsense, frameshift, and splice-site variants) in histone-lysine N-methyltransferase 2D () was much more prevalent in LUSC (11/53, 20.8%) than in LUAD (6/282, 2.1%). Moreover, our data indicated TP53 co-mutated with LoF in 90.9% (10/11) LUSC and 33.3% (2/6) LUAD. Notably, the mutation allele fraction (MAF) of was very similar to that of in the co-mutated cases. Genomic profiling of driver gene mutations of NSCLC showed that 81.8% (9/11) of the patients with LUSC with LoF mutations had amplification and/or amplification.
CONCLUSIONS
Our results prompted that somatic LoF mutations of occur frequently in LUSC, but are less frequent in LUAD and therefore may potentially contribute to the pathogenesis of LUSC. Concurrent mutations, amplification, and amplification are very common in LUSC cases with LoF mutations. It needs more deeper investigation on the interplay of the genes and pathways and uses larger cohorts in the future.
PubMed: 38883659
DOI: 10.21037/jtd-24-134 -
Heliyon Jun 2024N6-methyladenosine (m6A) methylation mediates cancer development by regulating cell proliferation and metastasis. This study aimed to identify whether methyltransferase...
N6-methyladenosine (m6A) methylation mediates cancer development by regulating cell proliferation and metastasis. This study aimed to identify whether methyltransferase 14 (METTL14) affects gastric cancer (GC) cellular functions and its underlying mechanism. METTL14 and TATA-box binding protein associated factor 10 (TAF10) levels were examined using quantitative real-time PCR, immunohistochemical assay, and Western blot. Biological functions were assessed using cell counting kit-8, colony formation, and transwell assays. The interaction between METTL14 and TAF10 was analyzed using RNA immunoprecipitation, methylated RNA immunoprecipitation, and luciferase reporter assay. A xenograft tumor mouse model was established to assess the role of METTL14 . The results suggested that METTL14 was low expressed and TAF10 was highly expressed in GC tissues and cells. METTL14 overexpression inhibited GC cell viability, colony, migration, and invasion. TAF10 was predicted and confirmed to be negatively related to METTL14. METTL14 promoted m6A methylation of TAF10 and inhibited TAF10 stability. Moreover, TAF10 counteracted the cellular behaviors regulated by METTL14. Overexpression of METTL14 inhibited tumor growth and histopathology. In conclusion, METTL14 inhibits GC progression by attenuating GC cell proliferation, migration, and invasion. Mechanistically, METTL14 promoted m6A methylation of TAF10, suppressed the stability of TAF10, and thus downregulated the TAF10 levels, These results provide a new insight into GC therapy.
PubMed: 38882361
DOI: 10.1016/j.heliyon.2024.e32014 -
Cureus Jun 2024This retrospective mono-center study focuses on 144 cases of glioblastoma treated over a time span of 12 years in our clinic in Romania. We offer critical insight into...
This retrospective mono-center study focuses on 144 cases of glioblastoma treated over a time span of 12 years in our clinic in Romania. We offer critical insight into the dreadful aspect of this tumor by highlighting the principal characteristics such as localization, the genetic information of each case, progression-free survival (PFS), and overall survival (OS). A tenth of our patients underwent a second surgical procedure, providing a comparable OS to the other part of our study group, proving that surgical treatment as salvage therapy is a viable option. Also, our research reinforces the fact that utilizing the Karnofsky Performance Scale is a great predictor of patient outcomes in glioblastoma patients. Even though radiotherapy and chemotherapy have mild effects in the context of this oncological disease, our research shows that O-methylguanine-DNA methyltransferase (MGMT) methylation status and epidermal growth factor receptor (EGFR) amplification have an important effect on OS. Moreover, the particularity of our study, that our patients did not start adjuvant therapy right after surgery, highlighted by a low OS compared to the international literature, sheds light on the fact that chemotherapy and radiotherapy must be started right after the surgical procedure, according to the Stupp protocol. To sum up, our research takes into consideration the factors that influence patient survival and outcome in the battle against glioblastoma.
PubMed: 38882229
DOI: 10.7759/cureus.62462 -
ACS Omega Jun 2024All organisms methylate their nucleic acids, and this methylation is critical for proper gene expression at both the transcriptional and translational levels. For proper...
All organisms methylate their nucleic acids, and this methylation is critical for proper gene expression at both the transcriptional and translational levels. For proper translation in eukaryotes, 2'--methylation of C (Cm) and G (Gm) in the anticodon loop of tRNA is critical, with defects in these modifications associated with human disease. In yeast, Cm is formed by an enzyme that consists of the methyltransferase Trm7 in complex with the auxiliary protein Trm732, and Gm is formed by an enzyme that consists of Trm7 in complex with Trm734. The role of Trm732 and Trm734 in tRNA modification is not fully understood, although previous studies have suggested that Trm734 is important for tRNA binding. In this report, we generated Trm734 variants and tested their ability to work with Trm7 to modify tRNA. Using this approach, we identified several regions of amino acids that are important for Trm734 activity and/or stability. Based on the previously determined Trm7-Trm734 crystal structure, these crucial amino acids are near the active site of Trm7 and are not directly involved in Trm7-Trm734 protein-protein interactions. Immunoprecipitation experiments with these Trm734 variants and Trm7 confirm that these residues are not involved in Trm7-Trm734 binding. Further experiments should help determine if these residues are important for tRNA binding or have another role in the modification of the tRNA. Furthermore, our discovery of a nonfunctional, stable Trm734 variant will be useful in determining if the reported roles of Trm734 in other biological processes such as retromer processing and resistance to Ty1 transposition are due to tRNA modification defects or to other bona fide cellular roles of Trm734.
PubMed: 38882062
DOI: 10.1021/acsomega.4c02313