miR-142-3p down-regulation contributes to thyroid follicular tumorigenesis by targeting ASH1L and MLL1

ASH1L in Hepatoma Cells and Hepatic Stellate Cells Promotes Fibrosis-Associated Hepatocellular Carcinoma by Modulating Tumor-Associated Macrophages

Hepatocellular carcinoma (HCC) often occurs in the context of fibrosis or cirrhosis. Methylation of histone is an important epigenetic mechanism, but it is unclear whether histone methyltransferases are potent targets for fibrosis-associated HCC therapy. ASH1L, an H3K4 methyltransferase, is found at higher levels in activated hepatic stellate cells (HSCs) and hepatoma cells. To determine the role of ASH1L in vivo, transgenic mice with conditional Ash1l depletion in the hepatocyte cell lineage (Ash1lflox/floxAlbcre) or HSCs (Ash1lflox/floxGFAPcreERT2) are generated, and these mice are challenged in a diethylnitrosamine (DEN)/carbon tetrachloride (CCl4)-induced model of liver fibrosis and HCC. Depleting Ash1l in both hepatocytes and HSCs mitigates hepatic fibrosis and HCC development. Multicolor flow cytometry, bulk, and single-cell transcriptomic sequencing reveal that ASH1L creates an immunosuppressive microenvironment. Mechanically, ASH1L-mediated H3K4me3 modification increases the expression of CCL2 and CSF1, which recruites and polarizes M2-like pro-tumorigenic macrophages. The M2-like macrophages further enhance tumor cell proliferation and suppress CD8+ T cell activation. AS-99, a small molecule inhibitor of ASH1L, demonstrates similar anti-fibrosis and tumor-suppressive effects. Of pathophysiological significance, the increased expression levels of mesenchymal ASH1L and M2 marker CD68 are associated with poor prognosis of HCC. The findings reveal ASH1L as a potential small-molecule therapeutic target against fibrosis-related HCC.

Whole-Exome Sequencing of Vulvar Squamous Cell Carcinomas Reveals an Impaired Prognosis in Patients With TP53 Mutations and Concurrent CCND1 Gains

Very little information is available on the mutational landscape of vulvar squamous cell carcinoma (VSCC), a disease that mainly affects older women. Studies focusing on the mutational patterns of the currently recognized etiopathogenic types of this tumor (human papillomavirus [HPV]-associated [HPV-A], HPV-independent [HPV-I] with TP53 mutation [HPV-I/TP53mut], and HPV-I with wild-type TP53 [HPV-I/TP53wt]) are particularly rare, and there is almost no information on the prognostic implications of these abnormalities.Whole-exome DNA sequencing of 60 VSCC and matched normal tissues from each patient was performed. HPV detection, immunohistochemistry (IHC) for p16, p53, and mismatch repair proteins were also performed. Ten tumors (16.7%) were classified as HPV-A, 37 (61.7%) as HPV-I/TP53mut, and 13 (21.6%) as HPV-I/TP53wt. TP53 was the most frequently mutated gene (66.7%), followed by FAT1 (28.3%), CDKN2A (25.0%), RNF213 (23.3%), NFE2L2 (20%) and PIK3CA (20%). All the 60 tumors (100%) were DNA mismatch repair proficient. Seventeen tumors (28.3%) showed CCND1 gain. Bivariate analysis, adjusted for International Federation of Gynecology and Obstetrics stage, revealed that TP53 mutation, CCND1 gain, and the combination of the 2 alterations were strongly associated with impaired recurrence-free survival (hazard ratio, 4.4; P < .001) and disease-specific survival (hazard ratio, 6.1; P = .002). Similar results were obtained when p53 IHC status was used instead of TP53 status and when considering only HPV-I VSCC. However, in the latter category, p53 IHC maintained its prognostic impact only in combination with CCND1 gains. All tumors carried at least one potentially actionable genomic alteration. In conclusion, VSCCs with CCND1 gain represent a prognostically adverse category among HPV-I/TP53mut tumors. All patients with VSCCs are potential candidates for targeted therapy.

miRNA-142-3p aggravates hydrogen peroxide-induced human umbilical vein endothelial cell premature senescence by targeting SIRT1

Vascular endothelial cell premature senescence plays an important part in stroke. Many microRNAs (miRNAs) are known to be involved in the pathological process of vascular endothelial cell premature senescence. The present study aimed to investigate the mechanism of hydrogen peroxide (H2O2)-induced premature senescence in human umbilical vein endothelial cells (HUVECs) and effect of miR-142-3p on hydrogen peroxide (H2O2)-induced premature senescence. HUVECs were exposed to H2O2 to establish a model premature senescence in endothelial cells. CCK-8 assay was performed to detect cell viability. Senescence-associated β-galactosidase staining assay and senescence-related proteins p16 and p21 were used to detect changes in the degree of cell senescence. RT-qPCR and Western blot were conducted to measure mRNA and protein levels, respectively. The scratch wound-healing assay, transwell assay, and EdU assay were performed to evaluate the ability of migration and proliferation, respectively. miRNA-142-3p and silencing information regulator 2 related enzyme 1 (SIRT1) binding was verified using Targetscan software and a dual-luciferase assay. We found that miRNA-142-3p is abnormally up-regulated in HUVECs treated with H2O2. Functionally, miRNA-142-3p inhibition may mitigate the degree of HUVEC senescence and improve HUVEC migration and proliferation. Mechanistically, SIRT1 was validated to be targeted by miRNA-142-3p in HUVECs. Moreover, SIRT1 inhibition reversed the effects of miRNA-142-3p inhibition on senescent HUVECs exposed to H2O2. To our knowledge, this is the first study to show that miRNA-142-3p ameliorates H2O2-induced HUVECs premature senescence by targeting SIRT1 and may shed light on the role of the miR-142-3p/SIRT1 axis in stroke treatment.

The histone methyltransferase ASH1L protects against bone loss by inhibiting osteoclastogenesis

Absent, small, or homeotic1-like (ASH1L) is a histone lysine methyltransferase that generally functions as a transcriptional activator in controlling cell fate. So far, its physiological relevance in bone homeostasis and osteoclast differentiation remains elusive. Here, by conditional deleting Ash1l in osteoclast progenitors of mice, we found ASH1L deficiency resulted in osteoporosis and potentiation of osteoclastogenesis in vivo and in vitro. Mechanistically, ASH1L binds the promoter of the Src homology 3 and cysteine-rich domain 2 (Stac2) and increases the gene's transcription via histone 3 lysine 4 (H3K4) trimethylation modification, thus augmenting the STAC2's protection against receptor activator of nuclear factor kB ligand (RANKL)-initiated inflammation during osteoclast formation. Collectively, we demonstrate the first piece of evidence to prove ASH1L as a critical checkpoint during osteoclastogenesis. The work sheds new light on our understanding about the biological function of ASH1L in bone homeostasis, therefore providing a valuable therapeutic target for the treatment of osteoporosis or inflammatory bone diseases.

MicroRNA-Mediated Regulation of Histone-Modifying Enzymes in Cancer: Mechanisms and Therapeutic Implications

In the past decade, significant advances in molecular research have provided a deeper understanding of the intricate regulatory mechanisms involved in carcinogenesis. MicroRNAs, short non-coding RNA sequences, exert substantial influence on gene expression by repressing translation or inducing mRNA degradation. In the context of cancer, miRNA dysregulation is prevalent and closely associated with various stages of carcinogenesis, including initiation, progression, and metastasis. One crucial aspect of the cancer phenotype is the activity of histone-modifying enzymes that govern chromatin accessibility for transcription factors, thus impacting gene expression. Recent studies have revealed that miRNAs play a significant role in modulating these histone-modifying enzymes, leading to significant implications for genes related to proliferation, differentiation, and apoptosis in cancer cells. This article provides an overview of current research on the mechanisms by which miRNAs regulate the activity of histone-modifying enzymes in the context of cancer. Both direct and indirect mechanisms through which miRNAs influence enzyme expression are discussed. Additionally, potential therapeutic implications arising from miRNA manipulation to selectively impact histone-modifying enzyme activity are presented. The insights from this analysis hold significant therapeutic promise, suggesting the utility of miRNAs as tools for the precise regulation of chromatin-related processes and gene expression. A contemporary focus on molecular regulatory mechanisms opens therapeutic pathways that can effectively influence the control of tumor cell growth and dissemination.

MicroRNA-142-3P suppresses the progression of papillary thyroid carcinoma by targeting FN1 and inactivating FAK/ERK/PI3K signaling

OBJECTIVES

miR-142-3P is a tumor suppressor in various malignant cancers. However, the function of miR-142-3P in papillary thyroid carcinoma (PTC) remains to be elucidated. The aim of this study was to explore the function and mechanism of miR-142-3P in PTC.

METHODS

Real Time Quantitative PCR (RT-qPCR) was used to assess the expression of miR-142-3P and Fibronectin 1 (FN1) in PTC. The correlation between FN1 and miR-142-3P expression was analyzed by Spearman's correlation analysis. Cell Counting Kit 8 (CCK8), 5-ethynyl-2'-deoxyuridine (EDU) assay, cell migration and invasion assay and wound healing measures evaluated the effect of miR-142-3P and FN1 on cell proliferation, migration and invasion. Dural Luciferase reported gene assay evaluated the interaction between miR-142-3P and 3' untranslated region (UTR) of FN1. The Epithelial-Mesenchymal-Transition (EMT) and apoptosis related marker genes were measured using western blot analysis (WB).

RESULTS

miR-142-3P was significantly decreased in both PTC specimens and relevant cell lines. Functionally, miR-142-3P inhibited cell proliferation, migration, invasion and EMT, and induced the cell apoptosis in PTC. In addition, miR-142-3P bound directly with 3' UTR of FN1 and negatively regulated the expression of FN1 in PTC. FN1 expression is elevated in PTC, and its aberrant high correlated with declines in recurrence-free survival (RFS). Moreover, FN1 promoted cell proliferation, migration, invasion and EMT, induced cell apoptosis in PTC cells. Depletion of FN1 rescues the effect of miR-142-3P inhibitor on cell proliferation, invasion, apoptosis and EMT via inactivating Focal Adhesion Kinase (FAK)/Extracellular Signal-Regulated Kinase (ERK) / Phosphoinostide 3-kinase (P13K) signaling.

CONCLUSION

miR-142-3P suppressed cell proliferation, migration, invasion and EMT through modulating FN1/FAK/ERK/PI3K signaling in PTC, suggesting it as a potential therapeutic target for PTC.

MiR-495-3p regulates cell migration and invasion in papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) is the most prevalent histotype of thyroid cancer and the presence of BRAFV600E mutation in these tumors is related to the malignancy and prognosis of the disease. In recent years attention has been focused on the role of microRNAs in the biology of PTC cells, especially in their role in the modulation of pathways related to tumorigenesis. DLK1-DIO3-derived miRNAs have been shown to play important roles in tumor context and are globally downregulated in PTC.

Methods

Based on a previous in silico target prediction and gene enrichment analysis, we identified miR-495-3p as the candidate with the highest tumor suppressor potential role in PTC among DLK1-DIO3-derived miRNAs. We used bioinformatics and an in vitro model of miR-495-3p overexpression to further understand the influence of this molecule on the tumorigenic processes of PTC.

Results

Overexpression of miR-495-3p impaired cell migration and invasion of PTC cells harboring the BRAFV600E mutation and affected the expression of targets predicted in the bioinformatic analysis, such as TGFB2, EREG and CCND1.

Conclusion

Overall, our results indicate that the loss of miR-495-3p expression during PTC development might play an important role in its progression.

Bromodomain (BrD) Family Members as Regulators of Cancer Stemness-A Comprehensive Review

Epigenetic mechanisms involving DNA methylation and chromatin modifications have emerged as critical facilitators of cancer heterogeneity, substantially affecting cancer development and progression, modulating cell phenotypes, and enhancing or inhibiting cancer cell malignant properties. Not surprisingly, considering the importance of epigenetic regulators in normal stem cell maintenance, many chromatin-related proteins are essential to maintaining the cancer stem cell (CSC)-like state. With increased tumor-initiating capacities and self-renewal potential, CSCs promote tumor growth, provide therapy resistance, spread tumors, and facilitate tumor relapse after treatment. In this review, we characterized the epigenetic mechanisms that regulate the acquisition and maintenance of cancer stemness concerning selected epigenetic factors belonging to the Bromodomain (BrD) family of proteins. An increasing number of BrD proteins reinforce cancer stemness, supporting the maintenance of the cancer stem cell population in vitro and in vivo via the utilization of distinct mechanisms. As bromodomain possesses high druggable potential, specific BrD proteins might become novel therapeutic targets in cancers exhibiting de-differentiated tumor characteristics.

Modulatory role of miRNAs in thyroid and breast cancer progression and insights into their therapeutic manipulation

Over the past few decades, thyroid cancer has become one of the most common types of endocrine cancer, contributing to an increase in prevalence. In the year 2020, there were 586,202 newly diagnosed cases of thyroid cancer around the world. This constituted approximately 3.0% of all patients diagnosed with cancer. The World Health Organization reported that there will be 2.3 million women receiving treatment for breast cancer in 2020, with 685,000. Despite the fact that carcinoma is one of the world's leading causes of death, there is still a paucity of information about its biology. MicroRNAs (miRNAs; miRs) are non-coding RNAs that can reduce gene expression by cleaving the 3' untranslated regions of mRNA. These factors make them a potential protein translation inhibitor. Diverse biological mechanisms implicated in the genesis of cancer are modulated by miRNA. The investigation of global miRNA expression in cancer showed regulatory activity through up regulation and down-regulation in several cancers, including thyroid cancer and breast cancer. In thyroid cancer, miRNA influences several cancers related signaling pathways through modulating MAPK, PI3K, and the RAS pathway. In breast cancer, the regulatory activity of miRNA was played through the cyclin protein family, protein kinases and their inhibitors, and other growth promoters or suppressors, which modulated cell proliferation and cell cycle progression. This article's goal is to discuss key miRNA expressions that are involved in the development of thyroid and breast cancer as well as their therapeutic manipulation for these two specific cancer types.

Structural insight into ASH1L PHD finger recognizing methylated histone H3K4 and promoting cell growth in prostate cancer

ASH1L is a member of the Trithorax-group protein and acts as a histone methyltransferase for gene transcription activation. It is known that ASH1L modulates H3K4me3 and H3K36me2/3 at its gene targets, but its specific mechanism of histone recognition is insufficiently understood. In this study, we found that the ASH1L plant homeodomain (PHD) finger interacts with mono-, di-, and trimethylated states of H3K4 peptides with comparable affinities, indicating that ASH1L PHD non-selectively binds to all three methylation states of H3K4. We solved nuclear magnetic resonance structures picturing the ASH1L PHD finger binding to the dimethylated H3K4 peptide and found that a narrow binding groove and residue composition in the methylated-lysine binding pocket restricts the necessary interaction with the dimethyl-ammonium moiety of K4. In addition, we found that the ASH1L protein is overexpressed in castrate-resistant prostate cancer (PCa) PC3 and DU145 cells in comparison to PCa LNCaP cells. The knockdown of ASH1L modulated gene expression and cellular pathways involved in apoptosis and cell cycle regulation and consequently induced cell cycle arrest, cell apoptosis, and reduced colony-forming abilities in PC3 and DU145 cells. The overexpression of the C-terminal core of ASH1L but not the PHD deletion mutant increased the overall H3K36me2 level but had no effect on the H3K4me2/3 level. Overall, our study identifies the ASH1L PHD finger as the first native reader that non-selectively recognizes the three methylation states of H3K4. Additionally, ASH1L is required for the deregulation of cell cycle and survival in PCas.

Structural and functional specificity of H3K36 methylation

The methylation of histone H3 at lysine 36 (H3K36me) is essential for maintaining genomic stability. Indeed, this methylation mark is essential for proper transcription, recombination, and DNA damage response. Loss- and gain-of-function mutations in H3K36 methyltransferases are closely linked to human developmental disorders and various cancers. Structural analyses suggest that nucleosomal components such as the linker DNA and a hydrophobic patch constituted by histone H2A and H3 are likely determinants of H3K36 methylation in addition to the histone H3 tail, which encompasses H3K36 and the catalytic SET domain. Interaction of H3K36 methyltransferases with the nucleosome collaborates with regulation of their auto-inhibitory changes fine-tunes the precision of H3K36me in mediating dimethylation by NSD2 and NSD3 as well as trimethylation by Set2/SETD2. The identification of specific structural features and various cis-acting factors that bind to different forms of H3K36me, particularly the di-(H3K36me2) and tri-(H3K36me3) methylated forms of H3K36, have highlighted the intricacy of H3K36me functional significance. Here, we consolidate these findings and offer structural insight to the regulation of H3K36me2 to H3K36me3 conversion. We also discuss the mechanisms that underlie the cooperation between H3K36me and other chromatin modifications (in particular, H3K27me3, H3 acetylation, DNA methylation and N6-methyladenosine in RNAs) in the physiological regulation of the epigenomic functions of chromatin.

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

Discovery of first-in-class inhibitors of ASH1L histone methyltransferase with anti-leukemic activity

ASH1L histone methyltransferase plays a crucial role in the pathogenesis of different diseases, including acute leukemia. While ASH1L represents an attractive drug target, developing ASH1L inhibitors is challenging, as the catalytic SET domain adapts an inactive conformation with autoinhibitory loop blocking the access to the active site. Here, by applying fragment-based screening followed by medicinal chemistry and a structure-based design, we developed first-in-class small molecule inhibitors of the ASH1L SET domain. The crystal structures of ASH1L-inhibitor complexes reveal compound binding to the autoinhibitory loop region in the SET domain. When tested in MLL leukemia models, our lead compound, AS-99, blocks cell proliferation, induces apoptosis and differentiation, downregulates MLL fusion target genes, and reduces the leukemia burden in vivo. This work validates the ASH1L SET domain as a druggable target and provides a chemical probe to further study the biological functions of ASH1L as well as to develop therapeutic agents.

MiR-142-3p targets HMGA2 and suppresses breast cancer malignancy

MicroRNAs (miRNAs) have the ability to regulate gene expression programs in cells. Hence, altered expression of miRNAs significantly contributes to breast cancer development and progression. Here, we demonstrate that the miRNA miR-142-3p directly targets the 3' untranslated region of HMGA2, which encodes an onco-embryonic protein that is overexpressed in most cancers, including breast cancer. Down regulation of miR-142-3p predicting poor patient survival in grade 3 breast cancer (P-value = 0.045). MiR-142-3p downregulates HMGA2 mRNA and protein levels. Higher miR-142-3p and lower HMGA2 expressed are found in breast cancer versus normal breast tissue (P-value<0.05), and their levels inversely correlate in breast cancers (P-value = 1.46 × 10^-4). We demonstrate that miR-142-3p induces apoptosis and G2/M cell cycle arrest in breast cancer cells. In addition, it inhibits breast cancer stem cell properties and decreases SOX2, NANOG, ALDH and c-Myc expression. MiR-142-3p also decreases cell proliferation through inhibition of the ERK/AKT/STAT3 signaling pathways. Finally, pathway analyses of patient samples suggest that these mechanisms also acting in the tumors of breast cancer patients. Thus, our work identifies HMGA2 as a direct miR-142-3p target and indicates that miR-142-3p is an important suppressor of breast cancer oncogenesis. This identifies miR-142-3p may candidate as a therapeutic molecule for breast cancer treatment.

Potential Regulatory Role of Human-Carboxylesterase-1 Glycosylation in Liver Cancer Cell Growth

We previously reported that human carboxylesterase 1 (CES1), a serine esterase containing a unique N-linked glycosyl group at Asn79 (N79 CES1), is a candidate serological marker of hepatocellular carcinoma (HCC). CES1 is normally present at low-to-undetectable levels in normal human plasma, HCC tumors, and major liver cancer cell lines. To investigate the potential mechanism underlying the suppression of CES1 expression in liver cancer cells, we took advantage of the low detectability of this marker in tumors by overexpressing CES1 in multiple HCC cell lines, including stable Hep3B cells. We found that the population of CES1-overexpressing (OE) cells decreased and that their doubling time was longer compared with mock control liver cancer cells. Using interactive transcriptome, proteome, and subsequent Gene Ontology enrichment analysis of CES1-OE cells, we found substantial decreases in the expression levels of genes involved in cell cycle regulation and proliferation. This antiproliferative function of the N79 glycan of CES1 was further supported by quantitative real-time polymerase chain reaction, flow cytometry, and an apoptosis protein array assay. An analysis of the levels of key signaling target proteins via Western blotting suggested that CES1 overexpression exerted an antiproliferative effect via the PKD1/PKCμ signaling pathway. Similar results were also seen in another HCC cell line (PLC/RFP/5) after transient transfection with CES1 but not in similarly treated non-HCC cell lines (e.g., HeLa and Tera-1 cells), suggesting that CES1 likely exerts a liver cell-type-specific suppressive effect. Given that the N-linked glycosyl group at Asn79 (N79 glycan) of CES1 is known to influence CES1 enzyme activity, we hypothesized that the post-translational modification of CES1 at N79 may be linked to its antiproliferative activity. To investigate the regulatory effect of the N79 glycan on cellular growth, we mutated the single N-glycosylation site in CES1 from Asn to Gln (CES1-N79Q) via site-directed mutagenesis. Fluorescence 2-D difference gel electrophoresis protein expression analysis of cell lysates revealed an increase in cell growth and a decrease in doubling time in cells carrying the N79Q mutation. Thus our results suggest that CES1 exerts an antiproliferative effect in liver cancer cells and that the single N-linked glycosylation at Asn79 plays a potential regulatory role. These functions may underlie the undetectability of CES1 in human HCC tumors and liver cancer cell lines. Mass spectrometry data are available via ProteomeXchange under the identifier PXD021573.

Mir142 loss unlocks IDH2R140-dependent leukemogenesis through antagonistic regulation of HOX genes

AML is a genetically heterogeneous disease and understanding how different co-occurring mutations cooperate to drive leukemogenesis will be crucial for improving diagnostic and therapeutic options for patients. MIR142 mutations have been recurrently detected in IDH-mutated AML samples. Here, we have used a mouse model to investigate the interaction between these two mutations and demonstrate a striking synergy between Mir142 loss-of-function and IDH2^R140Q, with only recipients of double mutant cells succumbing to leukemia. Transcriptomic analysis of the non-leukemic single and leukemic double mutant progenitors, isolated from these mice, suggested a novel mechanism of cooperation whereby Mir142 loss-of-function counteracts aberrant silencing of Hoxa cluster genes by IDH2^R140Q. Our analysis suggests that IDH2^R140Q is an incoherent oncogene, with both positive and negative impacts on leukemogenesis, which requires the action of cooperating mutations to alleviate repression of Hoxa genes in order to advance to leukemia. This model, therefore, provides a compelling rationale for understanding how different mutations cooperate to drive leukemogenesis and the context-dependent effects of oncogenic mutations.

Differential MicroRNA-Signatures in Thyroid Cancer Subtypes

Thyroid cancer is one of the most common endocrine cancers, with an increasing trend in the last few decades. Although papillary thyroid cancer is the most frequent subtype compared with follicular or anaplastic thyroid cancer, it can dedifferentiate to a more aggressive phenotype, and the recurrence rate is high. The cells of follicular adenomas and follicular carcinomas appear identical in cytology, making the preoperative diagnosis difficult. On the other hand, anaplastic thyroid cancer poses a significant clinical challenge due to its aggressive nature with no effective therapeutic options. In the past several years, the roles of genetic alterations of thyroid tumors have been documented, with a remarkable correlation between genotype and phenotype, indicating that distinct molecular changes are associated with a multistep tumorigenic process. Besides mRNA expression profiles, small noncoding microRNA (miRNA) expression also showed critical functions for cell differentiation, proliferation, angiogenesis, and resistance to apoptosis and finally activating invasion and metastasis in cancer. Several high-throughput sequencing studies demonstrate that miRNA expression signatures contribute clinically relevant information including types of thyroid cancer, tumor grade, and prognosis. This review summarizes recent findings on miRNA signatures in thyroid cancer subtypes.

Discriminating Origin Tissues of Tumor Cell Lines by Methylation Signatures and Dys-Methylated Rules

DNA methylation is an essential epigenetic modification for multiple biological processes. DNA methylation in mammals acts as an epigenetic mark of transcriptional repression. Aberrant levels of DNA methylation can be observed in various types of tumor cells. Thus, DNA methylation has attracted considerable attention among researchers to provide new and feasible tumor therapies. Conventional studies considered single-gene methylation or specific loci as biomarkers for tumorigenesis. However, genome-scale methylated modification has not been completely investigated. Thus, we proposed and compared two novel computational approaches based on multiple machine learning algorithms for the qualitative and quantitative analyses of methylation-associated genes and their dys-methylated patterns. This study contributes to the identification of novel effective genes and the establishment of optimal quantitative rules for aberrant methylation distinguishing tumor cells with different origin tissues.

Novel role of ASH1L histone methyltransferase in anaplastic thyroid carcinoma

Anaplastic thyroid cancer (ATC) is one of the most aggressive human malignancies, with an average life expectancy of ∼6 months from the time of diagnosis. The genetic and epigenetic changes that underlie this malignancy are incompletely understood. We found that ASH1-like histone lysine methyltransferase (ASH1L) is overexpressed in ATC relative to the much less aggressive and more common differentiated thyroid cancer. This increased expression was due at least in part to reduced levels of microRNA-200b-3p (miR-200b-3p), which represses ASH1L expression, in ATC. Genetic knockout of ASH1L protein expression in ATC cell lines decreased cell growth both in culture and in mouse xenografts. RNA-Seq analysis of ASH1L knockout versus WT ATC cell lines revealed that ASH1L is involved in the regulation of numerous cancer-related genes and gene sets. The pro-oncogenic long noncoding RNA colon cancer-associated transcript 1 (CCAT1) was one of the most highly (approximately 68-fold) down-regulated transcripts in ASH1L knockout cells. Therefore, we investigated CCAT1 as a potential mediator of the growth-inducing activity of ASH1L. Supporting this hypothesis, CCAT1 knockdown in ATC cells decreased their growth rate, and ChIP-Seq data indicated that CCAT1 is likely a direct target of ASH1L's histone methyltransferase activity. These results indicate that ASH1L contributes to the aggressiveness of ATC and suggest that ASH1L, along with its upstream regulator miR-200b-3p and its downstream mediator CCAT1, represents a potential therapeutic target in ATC.

The role of noncoding RNAs and sirtuins in cancer drug resistance

Cancer is a rising and major health issue around the world. The acquisition of resistance to chemotherapeutic drugs is a great obstacle for the effective treatment of nearly all cancers. Drug resistance is regulated by multiple factors and mechanisms including genetic mutations, abnormal expression of some cellular transporters such as multidrug resistance (MDR) transporters, changes in apoptotic pathways, cancer stem cells, tumor microenvironment, and noncoding RNAs (ncRNAs). Evidence clearly indicates a key role for sirtuins in several characteristics of cancer drug resistance. Recent studies demonstrated the crucial impact of some ncRNAs on sirtuins expression leading to modulation of chemotherapy resistance in cancers. In this review, we will focus on the current findings about the impacts of ncRNAs on the sirtuins pathway and their role in drug resistance of cancer.

MiR-142-3p functions as a tumor suppressor by targeting RAC1/PAK1 pathway in breast cancer

MicroRNA-142-3p (miR-142-3p) was previously investigated in various cancers, whereas, it's role in breast cancer (BC) remains far from understood. In this study, we found that miR-142-3p was markedly decreased both in cell lines and BC tumor tissues. Elevated miR-142-3p expression suppressed growth and metastasis of BC cell lines via gain-of-function assay in vitro and in vivo. Mechanistically, miR-142-3p could regulate the ras-related C3 botulinum toxin substrate 1 (RAC1) expression in protein level, which simultaneously suppressed the epithelial-to-mesenchymal transition related protein levels and the activity of PAK1 phosphorylation, respectively. In addition, rescue experiments revealed RAC1 overexpression could reverse tumor-suppressive role of miR-142-3p. Our results showed miR-142-3p could function as a tumor suppressor via targeting RAC1/PAK1 pathway in BC, suggesting a potent therapeutic target for BC treatment.

miR-142-3p is a tumor suppressor that inhibits estrogen receptor expression in ER-positive breast cancer

Estrogen receptors (ERs) are involved in the development of many types of malignant tumors, in particular, breast cancer. Among others, ERs affect cell growth, proliferation, and differentiation. The microRNA (miRNA) miR-142-3p has been shown to inhibit carcinogenesis by regulating various cellular processes, including cell cycle progression, cell migration, apoptosis, and invasion. It does so via targeting molecules involved in a range of signaling pathways. We surgically collected 20 ER-positive breast cancer samples, each with matched adjacent normal breast tissue, and measured the expression of miR-142-3p via quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics methods, luciferase reporter assay, qRT-PCR, and western blot analysis were used to assess whether miR-142-3p could target ESR1, which encodes the estrogen receptor, in ER-positive breast cancer cells and patient samples. We also restored miRNA expression and performed cell viability, cytotoxicity, and colony formation assays. Western blot analysis and qRT-PCR were used to study the expression of apoptosis and stemness markers. We found that miR-142-3p is downregulated in ER-positive breast cancers. Restoration of miR-142-3p expression in ER-positive breast cancer cells reduced cell viability, induced apoptosis via the intrinsic pathway and decreased both colony formation and the expression of stem cell markers. Bioinformatic analysis predicted miR-142-3p could bind to 3'-untranslated region ESR1 messenger RNA (mRNA). Consistently, we demonstrated that miR-142-3p reduced luciferase activity in ER-positive breast cancer cells, and decreased ESR1 expression in both mRNA and protein levels. The results revealed miR-142-3p and ESR1 expression correlated negatively in ER-positive breast cancer samples. The results suggest miR-142-3p acts as a tumor suppressor via multiple mechanisms. Thus, restoration of miR-142-3p expression, for example, via miRNA replacement therapy, may represent an effective strategy for the treatment of ER-positive breast cancer patients.

MicroRNA Dysregulation in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the second most frequent cancer in humans and it can be locally invasive and metastatic to distant sites. MicroRNAs (miRNAs or miRs) are endogenous, small, non-coding RNAs of 19–25 nucleotides in length, that are involved in regulating gene expression at a post-transcriptional level. MicroRNAs have been implicated in diverse biological functions and diseases. In cancer, miRNAs can proceed either as oncogenic miRNAs (onco-miRs) or as tumor suppressor miRNAs (oncosuppressor-miRs), depending on the pathway in which they are involved. Dysregulation of miRNA expression has been shown in most of the tumors evaluated. MiRNA dysregulation is known to be involved in the development of cutaneous squamous cell carcinoma (CSCC). In this review, we focus on the recent evidence about the role of miRNAs in the development of CSCC and in the prognosis of this form of skin cancer.

MicroRNAs and their target mRNAs as potential biomarkers among smokers and non-smokers with lung adenocarcinoma

Lung adenocarcinoma is one of the major causes of mortality. Current methods of diagnosis can be improved through identification of disease specific biomarkers. MicroRNAs are small non-coding regulators of gene expression, which can be potential biomarkers in various diseases. Thus, the main objective of this study was to gain mechanistic insights into genetic abnormalities occurring in lung adenocarcinoma by implementing an integrative analysis of miRNAs and mRNAs expression profiles in the case of both smokers and non-smokers. Differential expression was analysed by comparing publicly available lung adenocarcinoma samples with controls. Furthermore, weighted gene co-expression network analysis is performed which revealed mRNAs and miRNAs significantly correlated with lung adenocarcinoma. Moreover, an integrative analysis resulted in identification of several miRNA-mRNA pairs which were significantly dysregulated in non-smokers with lung adenocarcinoma. Also two pairs (miR-133b/Protein Kinase C Zeta (PRKCZ) and miR-557/STEAP3) were found specifically dysregulated in smokers. Pathway analysis further revealed their role in important signalling pathways including cell cycle. This analysis has not only increased the authors' understanding about lung adenocarcinoma but also proposed potential biomarkers. However, further wet laboratory studies are required for the validation of these potential biomarkers which can be used to diagnose lung adenocarcinoma.

Role of miR-142 in the pathogenesis of osteosarcoma and its potential as therapeutic approach

Osteosarcoma (OS) is the most common primary malignant tumor of the bone with a strong tendency to early metastasis, and occurs in growing bones more commonly in children and adolescents. Considering the limited therapeutic methods and lack of 100% success of these methods, developing innovative therapies with high efficacy and lower side effects is needed. Meanwhile, miRNAs and the studies indicating the involvement of miRNAs in OS development have attracted attentions as a result of the frequent abnormalities in expression of miRNAs in cancer. miRNAs are noncoding short sequences with lengths ranging from 18 to 25 nucleotides that play a very important role in cellular processes, such as proliferation, differentiation, migration, and apoptosis. MiRNAs can have either oncogenic or tumor suppressive role based on cellular function and targets. This review aimed to have overview on miR-142 as a tumor suppressor in OS. Moreover, the genes involved in the disease, such as RAC1, HMAG1, MMP9, MMP2, and E-cadherin, which have irregularities as a result of change in miR-142 expression, and, thereby, result in increasing the proliferation, invasion, and metastasis of the cells in the tissues and OS cells will be discussed.

Altered Epigenetic Mechanisms in Thyroid Cancer Subtypes

Thyroid carcinoma (TC) is the most frequent malignant neoplasm of the endocrine system. Molecular methods for diagnosis of invasive thyroid disease can be effectively adopted. Epigenetic factors play an important role in the diversity patterns of gene expression and the phenotypic and biological characteristics of TC subtypes. We aimed to review epigenetic changes in the main subtypes of TC, along with a presentation of the methods that have examined these changes, and active clinical trials for the treatment of advanced TCs targeting epigenetic changes. A literature analysis was performed in MEDLINE using PubMed, Elsevier, and Google Scholar for studies published up to 2016, using the keywords: "Epigenetic alterations" OR "Epigenetic changes", "thyroid cancers", "papillary thyroid cancer", "medullary thyroid cancer", "follicular thyroid cancer", and "anaplastic thyroid cancer", which resulted in 310 articles in English. All related abstracts were reviewed and studies were included that were published in English, had available full text, and determined the details of the methods and materials associated with the epigenetic patterns of TC and its subtypes (100 articles). Analysis of epigenetic alterations in TC subtypes helps to identify pathogenesis and can play an important role in the classification and diagnosis of tumors. Epigenetic mechanisms, especially aberrant methylation of DNA and microRNAs (miRs), are likely to play an important role in thyroid tumorigenesis. Further studies are required to elucidate the role of histone modification mechanisms in TC development.

MIR142 Loss-of-Function Mutations Derepress ASH1L to Increase HOXA Gene Expression and Promote Leukemogenesis

Point mutations in the seed sequence of miR-142-3p are present in a subset of acute myelogenous leukemia (AML) and in several subtypes of B-cell lymphoma. Here, we show that mutations associated with AML result both in loss of miR-142-3p function and in decreased miR-142-5p expression. Mir142 loss altered the hematopoietic differentiation of multipotent hematopoietic progenitors, enhancing their myeloid potential while suppressing their lymphoid potential. During hematopoietic maturation, loss of Mir142 increased ASH1L protein expression and consequently resulted in the aberrant maintenance of Hoxa gene expression in myeloid-committed hematopoietic progenitors. Mir142 loss also enhanced the disease-initiating activity of IDH2-mutant hematopoietic cells in mice. Together these data suggest a novel model in which miR-142, through repression of ASH1L activity, plays a key role in suppressing HOXA9/A10 expression during normal myeloid differentiation. AML-associated loss-of-function mutations of MIR142 disrupt this negative signaling pathway, resulting in sustained HOXA9/A10 expression in myeloid progenitors/myeloblasts and ultimately contributing to leukemic transformation.Significance: These findings provide mechanistic insights into the role of miRNAs in leukemogenesis and hematopoietic stem cell function. Cancer Res; 78(13); 3510-21. ©2018 AACR.

miR-142 suppresses proliferation and induces apoptosis of osteosarcoma cells by upregulating Rb

It has been reported that microRNA-142 (miR-142) is a tumor suppressor gene. The present study primarily investigated whether the overexpression of miR-142 was able to inhibit the proliferation, apoptosis and expression of apoptosis-associated proteins in osteosarcoma (OS) cells. Different concentrations of miR-142 were transfected into the OS MG-63 cell line using Lipofectamine 2000. The cell lines were divided into three groups: Normal group (non-transfected group), miR-142 transfected group, and negative group, which were transfected with random miR-142 fragment. The proliferation of cells was detected by MTT assay. The expression of miR-142 was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). DAPI staining was performed to investigate the influence of miR-142 on the morphology of MG-63c ells. The apoptotic cell percentages were determined by flow cytometry with Annexin V-fluorescein isothiocyanate/propidium iodide double staining. Expression of tumor suppressors, phosphatase and tensin homolog (PTEN) and Retinoblastoma-associated protein (Rb), and apoptosis-associated proteins were evaluated by western blotting. RT-qPCR indicated a higher expression of miR-142 in the transfected group (miR-142 was transfected into the MG-63 cell line) compared with that in the normal (non-transfected group) and negative control groups. The proliferation of miR-142 transfected cells was significantly lower compared with that in the normal and negative groups. Furthermore, an increased apoptosis rate accompanied by a statistically significant upregulation of PTEN, Rb phosphorylation, cleaved caspase-3 and cytochrome c protein levels were detected in the transfected group, indicating an internal apoptosis pathway was involved in this process. Furthermore, no significant changes were identified between the normal and negative groups (P>0.05). The present study demonstrated that miR-142 overexpression by liposomal transfection resulted in an inhibitory effect on MG-63 cell proliferation. The underlying mechanisms may relate to the upregulation of tumor suppressor and activation of caspase signaling pathway, which may provide a novel horizon in short nucleotide drugs on the management of OS.

MiR-135a-5p modulates biological functions of thyroid carcinoma cells via targeting VCAN 3'-UTR

Thyroid carcinoma is one of the most frequent malignant tumors of the endocrine system, which accounts for nearly 1% population in newly diagnosed carcinoma worldwide and the incidence has an increasing tendency in recent years. To explore whether miR-135a-5p could affect the proliferation, invasion and migration of thyroid carcinoma cells by targeting VCAN. The expression levels of miR-135a-5p and VCAN were detected in human thyroid carcinoma tissues and cells, para-carcinoma tissues, as well as human normal thyroid cells using RT-qPCR and Western blot. In addition, dual-luciferase reporter gene assay, MTT assay, colony formation assay, wound healing assay, Transwell assay, flow cytometry analysis and in vivo tumorigenesis assay were also conducted. The results demonstrated that miR-135a-5p was down-regulated while VCAN was up-regulated both in thyroid carcinoma tissues and cells. Furthermore, the up-regulation of miR-135a-5p inhibited cell proliferation, invasion and migration of thyroid carcinoma. Dual-luciferase reporter gene assay provided evidence indicating that miR-135a-5p targeted VCAN in thyroid carcinoma. MiR-135a-5p could inhibit cell proliferation, invasion and migration of thyroid carcinoma by targeting VCAN. MiR-135a-5p and VCAN might emerge as a target for the treatment of thyroid carcinoma.

MicroRNA-142-3p inhibits cell proliferation and chemoresistance in ovarian cancer via targeting sirtuin 1

MicroRNAs (miRs) serve promoting or suppressive roles in various human cancer types, including ovarian cancer; however, the role of miR-142-3p in ovarian cancer growth and chemoresistance has not previously been studied. In the present study, reverse transcription-quantitative polymerase chain reaction and western blotting were used to examine miR and protein expression levels. An MTT assay was used to examine cell proliferation. A luciferase reporter gene assay was used to clarify the target gene of miR-142-3p. The present study reported that miR-142-3p expression levels were significantly lower in ovarian cancer tissues and cell lines, when compared with those in adjacent tissues and the normal human ovarian epithelial cell line IOSE386, respectively. The reduced expression of miR-142-3p was significantly associated with poor cell differentiation. Ectopic expression of miR-142-3p significantly inhibited the proliferation of ovarian cancer cells and increased the sensitivity of SKOV3/DDP cells to cisplatin. Sirtuin 1 (SIRT1) was identified as a target gene of miR-142-3p; SIRT1 expression was negatively regulated by miR-142-3p in ovarian cancer cells. Further investigation demonstrated that SIRT1 reversed the suppressive effects of miR-142-3p on the proliferation and chemoresistance of ovarian cancer cells. In addition, SIRT1 was significantly upregulated in ovarian cancer. A negative correlation between the expression of SIRT1 and miR-142-3p in ovarian cancer tissues was also observed. In summary, the present study indicated that miR-142-3p inhibits the proliferation and chemoresistance of ovarian cancer cells by targeting SIRT1. This suggests that miR-142-3p may be a promising therapeutic candidate for the treatment of ovarian cancer.

Downregulation of microRNA-142-3p and its tumor suppressor role in gastric cancer

An increasing number of studies indicate that microRNAs (miRNAs) may exert an oncogenic or tumor suppressive role in diverse types of cancer. MicroRNA (miR)-142-3p has been detected to be downregulated in a number of cancer types, and it may function as a tumor suppressor. However, the expression profile and potential role of miR-142-3p in gastric cancer remain unknown. In the present study, the expression of miR-142-3p in numerous gastric cancer samples was investigated. It was observed that miR-142-3p was markedly downregulated in cancer tissues compared with normal tissues. Furthermore, a low expression level of miR-142-3p was associated with higher tumor stages. The overexpression of miR-142-3p was able to inhibit the proliferation, invasion and migration of gastric cancer cells. A further investigation into the mechanism underlying the effect of miR-142-3p identified cyclin T2 (CCNT2) as a target of miR-142-3p in gastric cancers. miR-142-3p may exert its tumor suppressor role partially by downregulating CCNT2. These results suggested that the abnormal downregulation of miR-142-3p and the subsequent increase in CCNT2 expression may have an important role in gastric cancer carcinogenesis.

Mrg15 stimulates Ash1 H3K36 methyltransferase activity and facilitates Ash1 Trithorax group protein function in Drosophila

Ash1 is a Trithorax group protein that possesses H3K36-specific histone methyltransferase activity, which antagonizes Polycomb silencing. Here we report the identification of two Ash1 complex subunits, Mrg15 and Nurf55. In vitro, Mrg15 stimulates the enzymatic activity of Ash1. In vivo, Mrg15 is recruited by Ash1 to their common targets, and Mrg15 reinforces Ash1 chromatin association and facilitates the proper deposition of H3K36me2. To dissect the functional role of Mrg15 in the context of the Ash1 complex, we identify an Ash1 point mutation (Ash1-R1288A) that displays a greatly attenuated interaction with Mrg15. Knock-in flies bearing this mutation display multiple homeotic transformation phenotypes, and these phenotypes are partially rescued by overexpressing the Mrg15-Nurf55 fusion protein, which stabilizes the association of Mrg15 with Ash1. In summary, Mrg15 is a subunit of the Ash1 complex, a stimulator of Ash1 enzymatic activity and a critical regulator of the TrxG protein function of Ash1 in Drosophila.

The Histone Methyltransferase Ash1l is Required for Epidermal Homeostasis in Mice

Epidermal homeostasis under normal and healing conditions are critical for the physical and functional maintenance of the skin barrier. It requires a proper balance between keratinocyte proliferation and differentiation under genetic and epigenetic regulations. Here we show that mice carrying a hypomorphic mutation of the histone methyltransferase Ash1l [(absent, small, or homeotic)-like (Drosophila)] develop epidermal hyperplasia and impaired epidermal stratification upon aging. In adult mutants, loss of Ash1l leads to more proliferative keratinocytes in disturbed differentiation stages. After wounding, Ash1l mutation leads to delayed re-epithlialization but increased keratinocyte proliferation at the wound edge. Elevated c-Myc expression could be observed in both aged and wounded mutant tissues. Taken together, these observations revealed an important role of the epigenetic regulator Ash1l in epidermal homeostasis.

Mitochondria and microRNA crosstalk in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of long-term impairments in higher cognitive functioning, including deficits in attention and memory. It is well known that some of these persistent deficits are related, in part, to ongoing secondary injury events characterized by pervasive biochemical and pathophysiological stressors, including a rapid and sustained phase of mitochondrial dysfunction. A loss of mitochondrial function impacts a number of important cellular events and we have begun to investigate the novel hypothesis that mitochondria play a critical role in regulating the cellular activity of specific microRNAs in response to cellular demands and stressors. In this special issue report, we summarize briefly the rationale for investigating the crosstalk between mitochondria and microRNA, and provide recent preliminary data suggesting that mitochondria-microRNA interactions are modified in response to TBI-related cellular stressors. We postulate that this interaction is critical for regulating appropriate cellular microRNA responses, which opens up opportunities for therapeutic interventions targeting both mitochondrial function and microRNA activity.

Epigenetic modulators of thyroid cancer

There are some well known factors involved in the etiology of thyroid cancer, including iodine deficiency, radiation exposure at early ages, or some genetic changes. However, epigenetic modulators that may contribute to development of these tumors and be helpful to for both their diagnosis and treatment have recently been discovered. The currently known changes in DNA methylation, histone modifications, and non-coding RNAs in each type of thyroid carcinoma are reviewed here.

Expression of MicroRNAs in Thyroid Carcinoma

MicroRNA (miRNA) are negative regulators of gene expression and subsequent protein production. This method of action translates into regulatory control over cellular processes, including development, signaling, metabolism, and apoptosis. A broad range of miRNA are shown to have abnormal expressions in thyroid cancers which could explain the pathology of tumor oncogenesis and disease progression. A review is conducted of the current research on miRNA dysregulation in thyroid cancers, including papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), anaplastic thyroid cancer (ATC), and medullary thyroid carcinoma (MTC). Dysregulated miRNA and their associated regulatory pathways are identified and their oncogenic and pathological significance are discussed.

ASH1L Suppresses Matrix Metalloproteinase through Mitogen-activated Protein Kinase Signaling Pathway in Pulpitis

INTRODUCTION

Pulpitis is an inflammation of dental pulp produced by a response to external stimuli. The response entails substantial cellular and molecular activities. Both genetic and epigenetic regulators contribute to the occurrence of pulpitis. However, the epigenetic mechanisms are still poorly understood. In this research, we studied the role of the absent, small, or homeotic-like (ASH1L) gene in the process of pulpitis.

METHODS

Human dental pulp cells (HDPCs) were stimulated with proinflammatory cytokine tumor necrosis factor alpha (TNF-α). Gene expression profiling was performed to assess the occurrence of epigenetic regulators. Pulp tissue from rat experimental pulpitis was subjected to immunofluorescence to detect the occurrence of ASH1L and trimethylation of lysine 4 histone 3 (H3K4me3). The presence of ASH1L in HDPCs that had been generated by TNF-α stimulation was analyzed by Western blot procedures and cellular immunofluorescence. Once detected, ASH1L was silenced through the use of specific small interfering RNA. The effects of ASH1L on the occurrence and operation of matrix metalloproteinases (MMPs) were then tested by analysis of quantitative polymerase chain reactions, Western blotting, and zymography. Chromatin immunoprecipitation was performed to detect whether ASH1L and H3K4me3 were present in the promoter regions of MMPs. We then used Western blot procedures to examine the nuclear factor kappa B and the mitogen-activated protein kinase (MAPK) responses to the silencing of ASH1L. We also examined the specific pathway involved in ASH1L regulation of the MMPs.

RESULTS

After stimulating HDPCs with TNF-α, ASH1L emerged as 1 of the most strongly induced epigenetic mediators. We found that TNF-α treatment induced the expression of ASH1L through the nuclear factor kappa B and MAPK signal pathways. ASH1L was found in both the nucleus and the cytoplasm. TNF-α treatment was particularly active in inducing the accumulation of ASH1L in cellular cytoplasm. As is also consistent with in vitro results, ASH1L was found in increased quantities in experimental dental pulpitis tissue. ASH1L knockdown markedly up-regulated the occurrence of MMP-1, MMP-2, and MMP-13. It also exercised an impact on the enzymatic activity of MMP-2 in HDPCs that had been stimulated with TNF-α. ASH1L knockdown activated the MAPK signal pathway in TNF-α-triggered HDPCs, the inhibition of which reversed the induction of MMPs.

CONCLUSIONS

Our research identifies a mechanism by which ASH1L suppresses the occurrence and operation of MMPs during pulpitis. It does this through the MAPK pathway.

MicroRNA-142-3p inhibits hypoxia/reoxygenation‑induced apoptosis and fibrosis of cardiomyocytes by targeting high mobility group box 1

Myocardial ischemia/reperfusion (I/R) injury may cause the apoptosis of cardiomyocytes as well as cardiac fibrosis, which is characterized as the transdifferentiation of fibroblasts to myofibroblasts and collagen deposition. MicroRNAs (miRNAs or miRs) have been demonstrated to be involved in myocardial I/R injury. However, the underlying molecular mechanism remains largely unclear. In the present study, mouse cardiomyocyte M6200 cells were treated with hypoxia/reoxygenation (H/R). Our data indicated that H/R treatment led to cell apoptosis, the increased expression of fibrosis-related proteins, namely collagen I, II, III, and fibronectin, as well as the downregulation of miR-142-3p in M6200 cells. Overexpression of miR-142-3p suppressed the H/R-induced apoptosis and fibrosis of M6200 cells. Bioinformatics analysis and a Dual-Luciferase reporter assay further identified high mobility group box 1 (HMGB1) as a direct target gene of miR-142-3p, and miR-142-3p negatively regulated the protein level of HMGB1 in M6200 cells. Furthermore, knockdown of HMGB1 enhanced cell proliferation whereas it inhibited the apoptosis and fibrosis of M6200 cells. In addition, TGF-β1/Smad3 signaling was suggested to be involved in the miR-142-3p/HMGB1-mediated apoptosis and fibrosis of M6200 cells treated with H/R. Taken together, the findings of the present study demonstrate that miR-142-3p inhibits H/R-induced apoptosis and fibrosis of cardiomyocytes, partly at least, by the direct inhibition of HMGB1 expression. Therefore, these findings have increased our understanding of the pathogenesis of H/R-induced myocardial injury.

H3K36 methyltransferases as cancer drug targets: rationale and perspectives for inhibitor development

Methylation at histone 3, lysine 36 (H3K36) is a conserved epigenetic mark regulating gene transcription, alternative splicing and DNA repair. Genes encoding H3K36 methyltransferases (KMTases) are commonly overexpressed, mutated or involved in chromosomal translocations in cancer. Molecular biology studies have demonstrated that H3K36 KMTases regulate oncogenic transcriptional programs. Structural studies of the catalytic SET domain of H3K36 KMTases have revealed intriguing opportunities for design of small molecule inhibitors. Nevertheless, potent inhibitors for most H3K36 KMTases have not yet been developed, underlining the challenges associated with this target class. As we now have strong evidence linking H3K36 KMTases to cancer, drug development efforts are predicted to yield novel compounds in the near future.

MECHANISMS IN ENDOCRINOLOGY: MicroRNA in diagnostics and therapy of thyroid cancer

MicroRNAs, short non-coding regulators of the gene expression, are subjects of numerous investigations assessing their potential use in the diagnostics and management of human diseases. In this review, we focus on studies that analyze the utility of microRNAs as novel diagnostic and therapeutic tools in follicular cell-derived thyroid carcinomas. This very interesting and promising field brings new insight into future strategies for personalized medicine.

Oncogenic microRNA-142-3p is associated with cellular migration, proliferation and apoptosis in renal cell carcinoma

MicroRNAs (miRNAs/miRs) serve an important role in the regulation of carcinogenic pathways. RCC is the most prevalent kidney cancer that occurs in adults. miRNAs have gained increasing attention due to their association with RCC tumorigenesis, serving as biomarkers for early detection and progression monitoring, and as potential targets for molecular therapy. Upregulation of miRNA-142-3p has been previously identified in RCC tissues by microarray profile, however, its expression and function in RCC have not yet been validated. In the present study, quantitative polymerase chain reaction was performed to quantify the relative expression of miR-142-3p in 53 paired RCC and adjacent normal tissues. Furthermore, wound healing, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and flow cytometry assays were performed to analyze the impacts of miR-142-3p on cellular migration, proliferation and apoptosis. The results demonstrated that miR-142-3p was significantly upregulated in RCC tissues compared with adjacent normal tissues. Downregulation of miR-142-3p, induced by chemically synthesized miR-142-3p inhibitor, significantly suppressed cell migration and proliferation, and promoted cell apoptosis in 786-O and ACHN cells, supporting the theory that miR-142-3p may function as an oncogene in RCC. The potential clinical significance of miR-142-3p, as a biomarker and therapeutic target, provides rationale for further investigation into the miR-142-3p-mediated molecular pathway and how it is associated with RCC development.

Two Loops Undergoing Concerted Dynamics Regulate the Activity of the ASH1L Histone Methyltransferase

ASH1L (absent, small, or homeotic-like 1) is a histone methyltransferase (HMTase) involved in gene activation that is overexpressed in multiple forms of cancer. Previous studies of ASH1L's catalytic SET domain identified an autoinhibitory loop that blocks access of histone substrate to the enzyme active site. Here, we used both nuclear magnetic resonance and X-ray crystallography to identify conformational dynamics in the ASH1L autoinhibitory loop. Using site-directed mutagenesis, we found that point mutations in the autoinhibitory loop that perturb the structure of the SET domain result in decreased enzyme activity, indicating that the autoinhibitory loop is not a simple gate to the active site but is rather a key feature critical to ASH1L function. We also identified a second loop in the SET-I subdomain of ASH1L that experiences conformational dynamics, and we trapped two different conformations of this loop using crystallographic studies. Mutation of the SET-I loop led to a large decrease in ASH1L enzymatic activity in addition to a significant conformational change in the SET-I loop, demonstrating the importance of the structure and dynamics of the SET-I loop to ASH1L function. Furthermore, we found that three C-terminal chromatin-interacting domains greatly enhance ASH1L enzymatic activity and that ASH1L requires native nucleosome substrate for robust activity. Our study illuminates the role of concerted conformational dynamics in ASH1L function and identifies structural features important for ASH1L enzymatic activity.