Mechanisms Of Tumorigenesis Research Articles

PATH-24. NOVEL MOLECULAR SUBTYPES IDENTIFIED IN INTRACRANIAL GERM CELL TUMORS SHOWED UNIQUE WHOLE-GENOME METHYLATION PROFILE

Abstract BACKGROUND By integrating whole-genome sequencing (WGS) and RNA-seq data, we found that intracranial germ cell tumors (IGCTs) can be divided into three distinct molecular subtypes: immune-hot, MYC/E2F, and SHH, each characterized by a unique profile of genomic abnormalities. To further define these subtypes, we subsequently performed whole-genome bisulfate sequencing (WGBS) on IGCT tumors METHODS Within our prior discovery cohort (n=110), DNA from 84 samples was available for profiling methylation levels using Whole Genome Bisulfite Sequencing (WGBS). Fastq data was aligned to the human reference genome (hg19), with duplicates removed, and DNA methylation was extracted using bismark pipeline (ver0.24.0). After quality control, weight methylation level was calculated for each CpG island as the sum of methylated reads divided by coverage. To identify IGCTs molecular groups, we applied hierarchical consensus k-means clustering to the most variant methylated CpG island (n=1000) across 84 IGCTs tumor tissues. The methylation level of RNA-seq subtypes was visualized to further clarify the molecular subtypes of IGCTs RESULTS Unsupervised clustering revealed that IGCTs can be divided into three groups based on the CpG island methylation levels: hypomethylation group (n=32), moderate methylation group (n=27), and hyper methylation group (n=25). The hypomethylation and moderate methylation group are predominantly observed in germinoma (>90%). In contrast, hypermethylation group comprises the majority of non-germinomatous germ cell tumors. Furthermore, these subgroups derived from methylation analysis are highly consistent with the molecular subtypes previously defined through gene transcription profile analysis. We observed that the majority of MYC/E2F subtype (24/33) belonged to the hypomethylation group, whereas the majority of immune-hot subtype (14/23) fell into the moderate methylation group. The SHH subtype was the most common within the hypermethylation group (18/26) CONCLUSIONS The three molecular IGCT subtypes showed unique methylation profile. These results indicate different mechanisms of tumorigenesis among the subtypes and pave the way for the clinical application of methylation-based subtyping.

Unveiling Tumorigenesis Mechanisms and Drug Therapy in Neuroblastoma by Mass Spectrometry Based Proteomics

Neuroblastoma (NB) is the most common type of extracranial solid tumors in children. Despite the advancements in treatment strategies over the past years, the overall survival rate in patients within the high-risk NB group remains less than 50%. Therefore, new treatment options are urgently needed for this group of patients. Compared with genomic aberrations, proteomic alterations are more dynamic and complex, as well as more directly related to pathological phenotypes and external perturbations such as environmental changes and drug treatments. This review focuses on specific examples of proteomics application in various fundamental aspects of NB research, including tumorigenesis, drug treatment, drug resistance, and highlights potential protein signatures and related signaling pathways with translational values for clinical practice. Moreover, emerging cutting-edge proteomic techniques, such as single cell and spatial proteomics, as well as mass spectrometry imaging, are discussed for their potentials to probe intratumor heterogeneity of NB.

Condensate remodeling reorganizes innate SS18 in synovial sarcomagenesis

SS18-SSX onco-fusion protein formed through aberrant chromosomal translocation t (X, 18; p11, q11), is the hallmark and plays a critical role in synovial sarcomagenesis. The recent works indicated that both the pathological SS18-SSX tumorigenic fusion and the corresponding intrinsic physiological SS18 protein can form condensates but appear to have disparate properties. The underlying regulatory mechanism and the consequent biological significance remain largely unknown. We show that the physical properties of oncogenic fusion protein SS18-SSX condensates within cells undergo alterations compared to the proto-oncogene protein SS18. By small-molecule screening and mutant assay, we identified the recognition of H2AK119ub histone modification could account for the distinctive properties of SS18-SSX1 condensates. Notably, we show that SS18-SSX1 condensates have impact on SS18 condensates and hijack that in a phase separation manner, resulting in the relocation of protein SS18 to the H2AK119ub modification targeted by SS18-SSX1. Consequently, this leads to the downregulation of tumor suppressor genes occupied by SS18 physiologically, like CAV1 and DAB2. These results reveal the underlying mechanism of genomic disorder and tumorigenesis caused by the remodeling of oncoprotein SS18-SSX1 condensates at the macroscopic level.

Pheochromocytoma-Paraganglioma Syndrome: A Multiform Disease with Different Genotype and Phenotype Features.

Pheochromocytoma and paraganglioma (PPGL) are rare tumors derived from the adrenal medulla and extra-adrenal chromaffin cells. Diagnosis is often challenging due to the great variability in clinical presentation; the complexity of management due to the dangerous effects of catecholamine excess and the potentially malignant behavior require in-depth knowledge of the pathology and multidisciplinary management. Nowadays, diagnostic ability has certainly improved and guidelines and consensus documents for treatment and follow-up are available. A major impulse to the development of this knowledge has come from the new findings on the genetic and molecular characteristics of PPGLs. Germline mutation in susceptibility genes is detected in 40% of subjects, with a mutation frequency of 10-12% also in patients with sporadic presentation and genetic testing should be incorporated within clinical care. PPGL susceptibility genes include "old genes" associated with Neurofibromatosis type 1 (NF1 gene), Von Hippel Lindau syndrome (VHL gene) and Multiple Endocrine Neoplasia type 2 syndrome (RET gene), the family of SDHx genes (SDHA, SDHB, SDHC, SDHD, SDHAF2), and genes less frequently involved such as TMEM, MAX, and FH. Each gene has a different risk of relapse, malignancy, and other organ involvement; for mutation carriers, affected or asymptomatic, it is possible to define a tailored long-life surveillance program according to the gene involved. In addition, molecular characterization of the tumor has allowed the identification of somatic mutations in other driver genes, bringing to 70% the PPGLs for which we know the mechanisms of tumorigenesis. This has expanded the catalog of tumor driver genes, which are identifiable in up to 70% of patients Integrated genomic and transcriptomic data over the last 10 years have revealed three distinct major molecular signatures, triggered by pathogenic variants in susceptibility genes and characterized by the activation of a specific oncogenic signaling: the pseudo hypoxic, the kinase, and the Wnt signaling pathways. These molecular clusters show a different biochemical phenotype and clinical behavior; they may also represent the prerequisite for implementing customized therapy and follow-up.

Conditional Pten inactivation in pituitary results in sex-specific prolactinoma formation

Pituitary tumors, including prolactinomas, present significant clinical challenges that require a deeper understanding of their molecular roots for improved diagnostics and therapies. Here, we investigate the role of the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K) pathway in pituitary tumorigenesis using a mouse model. Conditional knockout of Pten in all pituitary cell lineages resulted in prolactinoma formation exclusively in female mice, demonstrating the critical role of PTEN in pituitary homeostasis. While Pten inactivation induced Akt activation in all pituitary cells, only prolactin-producing cells exhibited tumorigenic changes, suggesting specific cell-type effects. Histological and molecular analyses of prolactinomas revealed similarities with human pituitary tumors, such as decreased vascularization and cell adhesion proteins and increased accumulation of cell cycle proteins. Notably, prolactinomas displayed diminished levels of phosphorylated extracellular signal-regulated kinase (ERK), implicating downregulation of ERK in tumorigenesis. Finally, we analyzed PTEN/PI3K activation in a collection of human pituitary tumors. Overall, our study delineates the intricate interplay between the PTEN and ERK signaling pathways, providing insights into sex-specific mechanisms of pituitary tumorigenesis and potential therapeutic strategies for prolactinomas.

ScTML: a pan-cancer single-cell landscape of multiple mutation types.

Investigating mutations, including single nucleotide variations (SNVs), gene fusions, alternative splicing and copy number variations (CNVs), is fundamental to cancer study. Recent computational methods and biological research have demonstrated the reliability and biological significance of detecting mutations from single-cell transcriptomic data. However, there is a lack of a single-cell-level database containing comprehensive mutation information in all types of cancer. Establishing a single-cell mutation landscape from the huge emerging single-cell transcriptomic data can provide a critical resource for elucidating the mechanisms of tumorigenesis and evolution. Here, we developed scTML (http://sctml.xglab.tech/), the first database offering a pan-cancer single-cell landscape of multiple mutation types. It includes SNVs, insertions/deletions, gene fusions, alternative splicing and CNVs, along with gene expression, cell states and other phenotype information. The data are from 74 datasets with 2 582 633 cells, including 35 full-length (Smart-seq2) transcriptomic single-cell datasets (all publicly available data with raw sequencing files), 23 datasets from 10X technology and 16 spatial transcriptomic datasets. scTML enables users to interactively explore multiple mutation landscapes across tumors or cell types, analyze single-cell-level mutation-phenotype associations and detect cell subclusters of interest. scTML is an important resource that will significantly advance deciphering intra-tumor and inter-tumor heterogeneity, and how mutations shape cell phenotypes.

Functional inversion of circadian regulator REV-ERBα leads to tumorigenic gene reprogramming

Profound functional switch of key regulatory factors may play a major role in homeostasis and disease. Dysregulation of circadian rhythm (CR) is strongly implicated in cancer with mechanisms poorly understood. We report here that the function of REV-ERBα, a major CR regulator of the orphan nuclear receptor subfamily, is dramatically altered in tumors in both its genome binding and functional mode. Loss of CR is linked to a functional inversion of REV-ERBα from a repressor in control of CR and metabolic gene programs in normal tissues to a strong activator in different cancers. Through changing its association from NCoR/HDAC3 corepressor complex to BRD4/p300 coactivators, REV-ERBα directly activates thousands of genes including tumorigenic programs such as MAPK and PI3K-Akt signaling. Functioning as a master transcriptional activator, REV-ERBα partners with pioneer factor FOXA1 and directly stimulates a large number of signaling genes, including multiple growth factors, receptor tyrosine kinases, RASs, AKTs, and MAPKs. Moreover, elevated REV-ERBα reprograms FOXA1 to bind new targets through a BRD4-mediated increase in local chromatin accessibility. Pharmacological targeting with SR8278 diminishes the function of both REV-ERBα and FOXA1 and synergizes with BRD4 inhibitor in effective suppression of tumorigenic programs and tumor growth. Thus, our study revealed a functional inversion by a CR regulator in driving gene reprogramming as an unexpected paradigm of tumorigenesis mechanism and demonstrated a high effectiveness of therapeutic targeting such switch.

8322 Mast Cells: a New Player in Gonadotroph Tumors

Abstract Disclosure: M. Ilie: None. M. Lepetit: None. M. Chanal: None. A. Vasiljevic: None. E. Jouanneau: None. O. Gandrillon: None. F. Picard: None. G. Raverot: None. P. Bertolino: None. Context: While gonadotroph tumors lack both prognostic markers and medical treatment options, the tumor microenvironment (TME) stands as a promising therapeutic and prognostic tool. Aim: Identify new TME players in gonadotroph tumors, gain insight into the mechanisms of tumorigenesis driven by these TME cells, and identify new TME-related prognostic markers and therapeutic targets. Methods: Data analysis of single-cell transcriptomics of 6 gonadotroph tumors and spatial transcriptomics of 3 gonadotroph tumors. Immunohistological validation on a cohort of 50 gonadotroph tumors, including 10 paired recurrent tumors. Results: 24,471 sequenced cells from the 6 tumors were analyzed. As expected, we found all previously TME-reported cell types (including stromal, endothelial, monocytes/macrophages, stem, and T cells) and identified mast cells as a new population in gonadotroph tumors. Tryptase immunostaining and whole slides analysis confirmed the presence of mast cells in all 50 gonadotroph tumors (range 0.01-4.33%). Ligand-receptor networks analysis, done with CellPhoneDB, identified bilateral crosstalk between mast cells and endothelial cells. VEGFA was the top ranked secreted ligand signaling from mast cells towards endothelial cells, suggesting a proangiogenic role for mast cells. Consistent with this hypothesis, the percentage of mast cells was very strongly correlated with the percentage of endothelial cells in the 6 tumors (Spearman’s rho=0.94, p=0.01). Spatial transcriptomics analysis showed that mast cells and endothelial cells were frequently colocalized, which was confirmed by double tryptase/CD34 immunofluorescence. We further found mast cells to express more VEGFA than TNF in the 6 sequenced tumors, which is suggestive of a pro-tumorigenic role. Using a clinical cohort, we confirmed the association of mast cells with a bad prognosis, as tumors progressing/relapsing more rapidly after surgery had more mast cells (p=0.002). In addition, more mast cells were present in the recurrent compared to the initial tumor for a same patient (p=0.007). Finally, bioinformatic analysis using Nichenet pinpointed KITLG (acting via KIT) to be one of the probable drivers of VEGFA expression in mast cells. Interestingly, KITLG-KIT was also the top ranked interaction between endothelial and mast cells. Conclusion: We identified and validated the presence of mast cells in gonadotroph tumors. The phenotype of mast cells was indicative of a bad prognosis, which was confirmed in a clinical cohort of 40 patients. Moreover, bilateral crosstalk between mast cells and endothelial cells was indicative of a mutual potentiation, suggesting that KIT and VEGFA targeting might be beneficial for the treatment of gonadotroph tumors. Presentation: 6/1/2024

Rab3B Proteins: Cellular Functions, Regulatory Mechanisms, and Potential as a Cancer Therapy Target.

RAB3 proteins, a pivotal subgroup within the Rab protein family, are known to be highly expressed in brain and endocrine gland tissues, with detectable levels also observed in exocrine glands, adipose tissue, and other peripheral tissues. They play an indispensable role in the trafficking of cellular products from the endoplasmic reticulum (ER) to the Golgi apparatus and ultimately to secretory vesicles, participating in vesicle transport, mediating cell membrane adhesion, and facilitating membrane fusion during exocytosis. Among these, Rab3B, a specific subtype of RAB3, is a low-molecular-weight (approximately 25 kD) GTP-binding protein (GTPase) characterized by its typical GTPase fold, composed of seven β-strands (six parallel and one antiparallel) surrounded by six α-helices. Previous studies have proved the significant roles of Rab3B in vesicle transport and hormone trafficking. However, its involvement in cancer remains largely unexplored. This review aims to dig into the potential mechanisms of Rab3B in various cancers, including hepatocellular cancer, lung adenocarcinoma, pancreatic cancer, breast cancer, prostate cancer, neuroblastoma and cervical cancer. Given its pivotal functions and underexplored status in oncology, Rab3B stands out as a promising target for both diagnosis and therapy in cancer treatment, with investigations into its biological mechanisms in tumorigenesis offering significant potential to advance future diagnostic and therapeutic strategies across various malignancies.

Revealing the Molecular Signatures of miR-185-5p on Breast Cancer Cells Using Proteomic Analysis.

Breast cancer is a heterogeneous type of disease in which genetic and environmental factors play a crucial role. There are several types of treatment for breast cancer (BC) patients. However, the biggest problem in the treatment of breast cancer is the resistance that occurs during the treatment with chemotherapeutic agents. Usnic acid, a secondary metabolite of lichen, has been identified as a drug candidate molecule in cancer treatment. The determination of miRNA target proteins is essential for the understanding of molecular mechanisms of miRNA-related tumorigenesis. We determined that mir-185-5p has therapeutic potential at the miRNA level by applying usnic acid to BT-474 breast cancer cells in a previous study. Herein, we aimed to investigate the molecular mechanisms of miR-185-5p on BT-474 breast cancer cells using a proteomics approach. We explored the changes in the protein expression level of BT-474 breast cancer cells in response to the up-regulation of miR-185-5p after applying usnic acid as a novel candidate anti-- cancer drug molecule. We performed quantitative proteome analysis based on an LC-MS/MS assay, which was validated by western blotting. The differentially expressed proteins were analyzed using the latest data available in bioinformatics tools. The up-regulated expression of YWHAE, Cathepsin D, and the down-regulated levels of PAK-1 were demonstrated by western blot assay. According to the results, 86 proteins showing >2-fold change were identified as differentially expressed between breast cancer and normal breast epithelial cells. The apoptosis pathway was the main clade containing most of the proteins regulated by miR-185-5p. The results indicate that miR-185-5p modulates apoptosis signaling pathways in BT-474 breast cancer cells. Breast cancer inhibition due to increased expression of YWHAE, Cathepsin D, and decreased expression of PAK-1 is likely to be mediated by inducing miR-185-5p mediated apoptosis. In this study, the identification of miR-185-5p protein targets demonstrated the potential for the development of targeted therapy and the development of miRNA-based therapeutics and presented it as a biomarker for breast cancer diagnosis, prognosis, and treatment response. In this regard, proteome analyses provided an understanding of the molecular mechanism underlying the effect of miR-185-5p on breast cancer.

Genome Engineering of Primary and Pluripotent Stem Cell-Derived Hepatocytes for Modeling Liver Tumor Formation.

Genome editing has demonstrated its utility in generating isogenic cell-based disease models, enabling the precise introduction of genetic alterations into wild-type cells to mimic disease phenotypes and explore underlying mechanisms. However, its application in liver-related diseases has been limited by challenges in genetic modification of mature hepatocytes in a dish. Here, we conducted a systematic comparison of various methods for primary hepatocyte culture and gene delivery to achieve robust genome editing of hepatocytes ex vivo. Our efforts yielded editing efficiencies of up to 80% in primary murine hepatocytes cultured in monolayer and 20% in organoids. To model human hepatic tumorigenesis, we utilized hepatocytes differentiated from human pluripotent stem cells (hPSCs) as an alternative human hepatocyte source. We developed a series of cellular models by introducing various single or combined oncogenic alterations into hPSC-derived hepatocytes. Our findings demonstrated that distinct mutational patterns led to phenotypic variances, affecting both overgrowth and transcriptional profiles. Notably, we discovered that the PI3KCA E542K mutant, whether alone or in combination with exogenous c-MYC, significantly impaired hepatocyte functions and facilitated cancer metabolic reprogramming, highlighting the critical roles of these frequently mutated genes in driving liver neoplasia. In conclusion, our study demonstrates genome-engineered hepatocytes as valuable cellular models of hepatocarcinoma, providing insights into early tumorigenesis mechanisms.

Unveiling the atlas of associations between 1,400 plasma metabolites and 24 tumors: Mendelian randomization analyses.

Association between plasma metabolites and pan-cancer remains controversial. Herein, we performed a two-sample Mendelian randomization (MR) analysis to verify whether there is a causal relationship between the two and to point the way for cancer metabolism research. In our research, we downloaded 1,400 plasma metabolites from a large genome-wide association study (GWAS). We also obtained GWAS summary statistics for 24 types of cancers from the publicly available GWAS database, totaling 5,003,410 European individuals. We mainly used the fixed/random-effects inverse variance-weighted (IVW) method for two-sample MR analysis. In a combined sample of 291,202 cancer cases and 4,712,208 controls, a total of 55 plasma metabolites were identified as causally associated with nine types of cancer as a result of our MR analysis [P<0.05, false discovery rate (FDR) <0.2], including methionine sulfone, gamma-glutamylcitrulline, alliin, tetradecanedioate, hexadecanedioate, glutarate, ceramide, linolenoylcarnitine, hydroxypalmitoyl sphingomyelin, 1-palmitoyl-2-linoleoyl-glycerylphosphorylcholine (1-palmitoyl-2-linoleoyl-GPC), 3-acetylphenol sulfate, retinol (vitamin a) to linoleoyl-arachidonoyl-glycerol (18:2 to 20:4) ratio, etc. Reverse MR analysis revealed a causal relationship between lung cancer and the only plasma metabolite, 1-palmitoyl-2-linoleoyl-GPC (P<0.05, FDR <0.2). Our study provides a comprehensive atlas of cancer-related plasma metabolites, offering possible targets for cancer detection, as well as a reference for future research on tumorigenesis mechanisms and therapeutic targets.

260. LOW BLOOD LEVEL OF TUMOR SUPPRESSOR MIR-3619 AS A TARGET OF NUCLEIC ACID THERAPY TO PIM-1 IN ESOPHAGEAL CANCER

Abstract Background Numerous studies have attempted to understand the molecular mechanisms of tumorigenesis and identify clinical biomarkers and molecular targets for esophageal squamous cell carcinoma (ESCC). However, there are still only a few biomarkers and targets. We focused on tumor suppressor micro-RNA (miR)s in the plasma of ESCC patients, and we investigated the usefulness of these tumor suppressor miRs as biomarkers and therapeutic agents for ESCC. Methods: Plasma samples of 94 ESCC patients and 86 healthy volunteers were analyzed in this study. Among the group of 2600 miRs candidates registered in miRbase, we selected 25 miRs candidates which are low expressed in ESCC tissues, have tumor suppressive functions, and unreported as a body fluid biomarker. We selected 5 miRs (miR-564/ 637/ 1182/ 3178/ 3619), whose signals were detectable in the blood of healthy volunteers by microarray analysis. By test-scale analysis using TaqMan assay and validation analysis, we identified miR-3619, which showed the most significant difference in ESCC patients compared to healthy volunteers (p &amp;lt; 0.001). Results: 1) Prognostic analysis revealed that a low miR-3619 plasma level was significantly associated with advanced stage and recurrence rate, and was an independent factor predicting poor prognosis in ESCC patients (p = 0.028, HR = 2.09). 2) Overexpression of miR-3619 mimic inhibited the proliferation of ESCC cells, induced the accumulation of apoptosis or G1/S phase cells, and reduced the cell migration and invasion abilities compared with negative control mimic. 3) We tested PIM-1xas candidate putative target genes for miR-3619 using microRNA database. PIM-1 protein expression levels were decreased in miR-3619-5p transfectants compared with NC. 4) In vivo, subcutaneous injection of miR-3619 could significantly inhibit tumor growth in mice. Administration of miR-3619 did not cause any clinical adverse events or side effects in blood-based parameters reflecting organ disorders. Conclusion: These results suggest that depleted tumor-suppressor miR-3619 in plasma could be one of blood-based biomarkers for predicting malignant potential of ESCC.

Integrative Network Pharmacology Unveils Limonia acidissima as a Potential Natural Product for Targeting Cancer

Cancer remains a formidable health challenge worldwide, with complex molecular mechanisms driving its initiation, progression, and therapeutic resistance. In this study, we employed bioinformatics analyses to elucidate the molecular underpinnings of cancer biology, focusing on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Our GO analysis revealed the enrichment of key biological processes such as protein phosphorylation, regulation of programmed cell death, and transmembrane receptor signaling pathways, underscoring the critical roles of signaling cascades and regulatory mechanisms in tumorigenesis. Similarly, molecular functions such as protein kinase activity and ATP binding were identified as significantly enriched, highlighting the importance of protein kinases and molecular interactions in cancer development and progression. The KEGG pathway analysis further delineated dysregulated signaling pathways associated with cancer, including the MAPK and PI3K-Akt signaling pathways, implicating these pathways as central regulators of cancer progression. These findings deepen our understanding of cancer biology and offer potential targets for therapeutic intervention. Integrating multi-omics data and systems biology approaches may provide deeper insights into the intricate networks underlying cancer pathogenesis, paving the way for developing more effective treatments for cancer patients.

Tumor-derived RHOA mutants interact with effectors in the GDP-bound state

RHOA mutations are found at diverse residues in various cancer types, implying mutation- and cell-specific mechanisms of tumorigenesis. Here, we focus on the underlying mechanisms of two gain-of-function RHOA mutations, A161P and A161V, identified in adult T-cell leukemia/lymphoma. We find that RHOAA161P and RHOAA161V are both fast-cycling mutants with increased guanine nucleotide dissociation/association rates compared with RHOAWT and show reduced GTP-hydrolysis activity. Crystal structures reveal an altered nucleotide association in RHOAA161P and an open nucleotide pocket in RHOAA161V. Both mutations perturb the dynamic properties of RHOA switch regions and shift the conformational landscape important for RHOA activity, as shown by 31P NMR and molecular dynamics simulations. Interestingly, RHOAA161P and RHOAA161V can interact with effectors in the GDP-bound state. 1H-15N HSQC NMR spectra support the existence of an active population in RHOAA161V-GDP. The distinct interaction mechanisms resulting from the mutations likely favor an RHOAWT-like “ON” conformation, endowing GDP-bound state effector binding activity.

Targeting POLD1 to suppress the proliferation and migration of breast cancer MDA-MB-231 cell lines by downregulation of SIRT1.

The resistant and aggressive nature of triple-negative breast cancer (TNBC) renders it mostly incurable even following extensive multimodal treatment. Therefore, more studies are required to understand the underlying molecular mechanisms of its pathogenesis. SIRT1 is a class III histone deacetylase NAD+-dependent enzyme that is interlinked in tumor progression, apoptosis, metastasis, and other mechanisms of tumorigenesis, while DNA polymerase delta 1 (POLD1) functions as a gene coding for p125, which plays an important role in genome stability and DNA replication. We aimed to investigate the downstream signaling pathway of EX-527, a potent and selective SIRT1 inhibitor, in MDA-MB-231 breast cancer cell lines, and the crosstalk between SIRT1 and POLD1, which is essential for the activities of polymerase δ. The antiproliferative and apoptotic effects of EX-527 on MDA-MB-231 cells were assessed by MTT and annexin V/PI double staining assays. Migration and invasion activity of MDA-MB-231 cells were assessed by wound-healing scratch and transwell assays. Protein expressions were examined using Western Blot analysis. MDA-MB-231 cells treatment with IC50 values of 45.3μM EX-527 significantly suppressed cell proliferation and induced apoptosis by down-regulating SIRT1. Also, it significantly repressed migration and invasion of MDA-MB-231 cells as evaluated by wound healing and transwell invasion assays. Western blot results showed that decreased expression of SIRT1 is positively correlated with expression of p53 along with down-regulating POLD1. SIRT1 could have an oncogenic role in breast cancer development and progression via activating POLD1. These conclusions present new insights into the underlying mechanisms of TNBC.

Retinoic acid receptor-related orphan receptor alpha and synthetic RORα agonist against invasion and metastasis in tongue squamous cell carcinoma

Retinoic acid receptor-related orphan receptor alpha (RORα), an essential tumor suppressor in a range of human malignancies, is classified as a member of the orphan nuclear receptor family. The most prevalent form of oral cancer, tongue squamous cell carcinoma (TSCC) is characterized by its severe malignancy and unfavorable prognosis. However, the extent to which its tumorigenesis mechanisms are associated with RORα expression levels is still not fully understood. The objective of this study was to examine the molecular mechanisms by which RORα is involved in TSCC. Through the use of immunohistochemistry (IHC), it was discovered that the expression level of RORα was significantly downregulated in TSCC tissues when compared to adjacent normal tissues in this study. To further investigate the role of RORα in TSCC, we activated the expression of RORα in human TSCC cell line (SCC9 cells) by transfecting RORα cDNA and using the selective RORα agonist SR1078. The results show that RORα can significantly inhibit the invasion, migration, proliferation, and adhesion of TSCC cells and induce cell apoptosis. In addition, xenograft models confirmed the conclusion that stable activation or treatment with SR1078 to increase RORα content significantly inhibited tumor growth and development. Taken together, this study provides solid evidence for the inhibitory role of RORα in the progression of TSCC. In addition, the preliminary application results of SR1078 in TSCC show that SR1078 is expected to be a potential therapeutic medication for TSCC. These findings provide innovative perspectives on the development of potential biomarkers and agents for TSCC therapy. The objective is to introduce novel strategy and alternatives for the prevention and treatment of TSCC.

SETD8 inhibits apoptosis and ferroptosis of Ewing’s sarcoma through YBX1/RAC3 axis

Ewing’s sarcoma (ES) represents a rare yet exceedingly aggressive neoplasm that poses a significant health risk to the pediatric and adolescent population. The clinical outcomes for individuals with relapsed or refractory ES are notably adverse, primarily attributed to the constrained therapeutic alternatives available. Despite significant advancements in the field, molecular pathology-driven therapeutic strategies have yet to achieve a definitive reduction in the mortality rates associated with ES. Consequently, there exists an imperative need to discover innovative therapeutic targets to effectively combat ES. To reveal the mechanism of the SETD8 (also known as lysine methyltransferase 5A) inhibitor UNC0379, cell death manners were analyzed with different inhibitors. The contributions of SETD8 to the processes of apoptosis and ferroptosis in ES cells were evaluated employing the histone methyltransferase inhibitor UNC0379 in conjunction with RNA interference techniques. The molecular regulatory mechanisms of SETD8 in ES were examined through the application of RNA sequencing (RNA-seq) and mass spectrometry-based proteomic analysis. Moreover, nude mouse xenograft models were established to explore the role of SETD8 in ES in vivo. SETD8, a sole nucleosome-specific methyltransferase that catalyzes mono-methylation of histone H4 at lysine 20 (H4K20me1), was found to be upregulated in ES, and its overexpression was associated with dismal outcomes of patients. SETD8 knockdown dramatically induced the apoptosis and ferroptosis of ES cells in vitro and suppressed tumorigenesis in vivo. Mechanistic investigations revealed that SETD8 facilitated the nuclear translocation of YBX1 through post-transcriptional regulatory mechanisms, which subsequently culminated in the transcriptional upregulation of RAC3. In summary, SETD8 inhibits the apoptosis and ferroptosis of ES cells through the YBX1/RAC3 axis, which provides new insights into the mechanism of tumorigenesis of ES. SETD8 may be a potential target for clinical intervention in ES patients.

Trends and hot spots in research related to aqueous humor from 2014 to 2023: A bibliometric analysis

PurposeTo analyze publication trends and investigate research hotspots of aqueous humor (AH) studies. MethodsA bibliometric study was conducted based on the Web of Science Core Collection (WOSCC). VOSviewer v. 1.6.18 was utilized to create a knowledge map visualizing the number of annual publications, the distribution of countries, international collaborations, author productivity, source journals and keywords in the field. ResultsA grand total of 4020 peer-reviewed papers concerning AH were retrieved from 2014 to 2023. The United States of America secured the top position among the most published countries and Duke University emerged as the most active institution. Stamer, WD contributed the most papers in this area. Investigative Ophthalmology & Visual Science was the most prolific journal in AH research. Retrieved publications mainly concentrated on the correlation between AH as a biomarker carrier and different ocular disorders. Six clusters were formed based on the keywords: (1) the diagnosis of endophthalmitis and AH pharmacokinetics; (2) the association of AH with pathogenesis and prognosis of glaucoma; (3) diagnosis and treatment of AH associated with uveitis; (4) the relationship between AH and refractive diseases of the eye; (5) the association of AH with mechanism and biomarkers of ocular tumorigenesis; (6) the indicators of AH associated with fundus disease. ConclusionsThis study unveiled present patterns of global collaboration, emerging frontiers, fundamental knowledge, research hotspots and current trends in AH.

LINC00891 Promotes Tumorigenesis and Metastasis of Thyroid Cancer by Regulating SMAD2/3 via EZH2.

Thyroid cancer (TC), the most common endocrine malignant tumor, is increasingly causing a huge threat to our health nowadays. To explore the tumorigenesis mechanism of thyroid cancer, we identified that long intergenic non-coding RNA-00891 (LINC00891) was upregulated in TC using the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and local databases. LINC00891 expression was correlated with histological type and lymph node metastasis (LNM). The high expression of LINC00891 could serve as a diagnostic marker for TC and its LNM. In vitro experiments demonstrated that LINC00891 knockdown could inhibit cell proliferation, migration, invasion and prompt apoptosis and G1 arrest of TC cells. We also investigated the related mechanisms of LINC00891 promoting TC progression using RNA sequencing, Gene Set Enrichment Analysis, and Western blotting. Our experiments demonstrated that LINC00891 promoted TC progression via the EZH2-SMAD2/3 signaling axis. In addition, overexpression of EZH2 could reverse the suppressive epithelial-to-mesenchymal transition (EMT) caused by LINC00891 knockdown. In conclusion, the LINC00891/EZH2/SMAD2/3 regulatory axis participated in tumorigenesis and metastasis of thyroid cancer, which may provide a novel target for treatment.