The histone methyltransferase Wolf-Hirschhorn syndrome candidate 1-like 1 (WHSC1L1) is involved in human carcinogenesis

Design, synthesis, and antitumor activity of NSDs inhibitors targeting lung squamous cell carcinoma

Lung squamous cell carcinoma (LUSC), a highly aggressive subtype of lung cancer, presents significant therapeutic challenges due to its complex molecular underpinnings. Recently, NSD3 has been identified as a key driver in the pathogenesis of LUSC, providing a new direction for targeted interventions. Herein, we report the rational design, synthesis, and comprehensive biological evaluation of a series of NSD3 inhibitors, culminating in the identification of compound A8, which demonstrates potent inhibitory activity against NSD3 and LUSC cell proliferation, with an IC50 of 0.355 μM in NCI-H1703 cells, and less toxicity to non-cancerous HEK293T cells. Cellular thermal shift assays confirmed the binding affinity of compound A8 for NSD3, promoting protein stabilization. Mechanistic investigations revealed that compound A8 induces apoptosis in LUSC cells in a dose-dependent manner and exhibits significant antitumor effects in both in vitro and in vivo models. Notably, compound A8 displayed favorable pharmacokinetic properties and efficaciously suppressed tumor growth in an NCI-H520 xenograft mouse model without observable adverse effects. These findings collectively establish compound A8 as a promising candidate for the development of targeted therapies against LUSC, highlighting the therapeutic potential of NSD3 inhibition.

In silico study to identify novel NEK7 inhibitors from natural sources by a combination strategy

Cancer poses a significant global health challenge and significantly contributes to mortality. NEK7, related to the NIMA protein kinase family, plays a crucial role in spindle assembly and cell division. The dysregulation of NEK7 is closely linked to the onset and progression of various cancers, especially colon and breast cancer, making it a promising target for cancer therapy. Nevertheless, the shortage of high-quality NEK7 inhibitors highlights the need for new therapeutic strategies. In this study, we utilized a multidisciplinary approach, including virtual screening, molecular docking, pharmacokinetics, molecular dynamics simulations (MDs), and MM/PBSA calculations, to evaluate natural compounds as NEK7 inhibitors comprehensively. Through various docking strategies, we identified three natural compounds: (-)-balanol, digallic acid, and scutellarin. Molecular docking revealed significant interactions at residues such as GLU112 and ALA114, with docking scores of -15.054, -13.059, and -11.547 kcal/mol, respectively, highlighting their potential as NEK7 inhibitors. MDs confirmed the stability of these compounds at the NEK7-binding site. Hydrogen bond analysis during simulations revealed consistent interactions, supporting their strong binding capacity. MM/PBSA analysis identified other crucial amino acids contributing to binding affinity, including ILE20, VAL28, ILE75, LEU93, ALA94, LYS143, PHE148, LEU160, and THR161, crucial for stabilizing the complex. This research demonstrated that these compounds exceeded dabrafenib in binding energy, according to MM/PBSA calculations, underscoring their effectiveness as NEK7 inhibitors. ADME/T predictions showed lower oral toxicity for these compounds, suggesting their potential for further development. This study highlights the promise of these natural compounds as bases for creating more potent derivatives with significant biological activities, paving the way for future experimental validation.

Predicting fragment binding modes using customized Lennard-Jones potentials in short molecular dynamics simulations

Reliable in silico prediction of fragment binding modes remains a challenge in current drug design research. Due to their small size and generally low binding affinity, fragments can potentially interact with their target proteins in different ways. In the current study, we propose a workflow aimed at predicting favorable fragment binding sites and binding poses through multiple short molecular dynamics simulations. Tailored Lennard-Jones potentials enable the simulation of systems with high concentrations of identical fragment molecules surrounding their respective target proteins. In the present study, descriptors and binding free energy calculations were implemented to filter out the desired fragment position. The proposed method was tested for its performance using four epigenetic target proteins and their respective fragment binders and showed high accuracy in identifying the binding sites as well as predicting the native binding modes. The approach presented here represents an alternative method for the prediction of fragment binding modes and may be useful in fragment-based drug discovery when the corresponding experimental structural data are limited.

Recent advances in targeting histone H3 lysine 36 methyltransferases for cancer therapy

Histone H3 lysine 36 (H3K36) methylation is a typical epigenetic histone modification that is involved in various biological processes such as DNA transcription, repair and recombination in vivo. Mutations, translocations, and aberrant gene expression associated with H3K36 methyltransferases have been implicated in different malignancies such as acute myeloid leukemia, lung cancer, multiple myeloma, and others. Herein, we provided a comprehensive overview of the latest advances in small molecule inhibitors targeting H3K36 methyltransferases. We analyzed the structures and biological functions of the H3K36 methyltransferases family members. Additionally, we discussed the potential directions for future development of inhibitors targeting H3K36 methyltransferases.

Discovery of potent small molecule inhibitors of histone lysine methyltransferase NSDs

Nuclear receptor binding SET domain (NSD) proteins are a class of histone lysine methyltransferases and implicated in multiple cancer types with aberrant expression and involvement of cancer related signaling pathways. In this study, a series of small-molecule compounds including compound 2 and 3 are identified against the SET domain of NSDs through structure-based virtual screening. Our lead compound 3 exhibits potent inhibitory activities in vitro towards the NSD2-SET and NSD3-SET with an IC50 of 0.81 μM and 0.84 μM, respectively, and efficiently inhibits histone H3 lysine 36 dimethylation and decreases the expression of NSDs-targeted genes in non-small cell lung cancer cells at 100 nM. Compound 3 suppresses cell proliferation and reduces the clonogenicity in H460 and H1299 non-small cell lung cancer cells, and induces s-phase cell cycle arrest and apoptosis. These data establish our compounds as a valuable tool-kit for the study of the biological roles of NSDs in cancer.

NSD3 in Cancer: Unraveling Methyltransferase-Dependent and Isoform-Specific Functions

NSD3 (nuclear receptor-binding SET domain protein 3) is a member of the NSD histone methyltransferase family of proteins. In recent years, it has been identified as a potential oncogene in certain types of cancer. The NSD3 gene encodes three isoforms, the long version (NSD3L), a short version (NSD3S) and the WHISTLE isoforms. Importantly, the NSD3S isoform corresponds to the N-terminal region of the full-length protein, lacking the methyltransferase domain. The chromosomal location of NSD3 is frequently amplified across cancer types, such as breast, lung, and colon, among others. Recently, this amplification has been correlated to a chromothripsis event, that could explain the different NSD3 alterations found in cancer. The fusion proteins containing NSD3 have also been reported in leukemia (NSD3-NUP98), and in NUT (nuclear protein of the testis) midline carcinoma (NSD3-NUT). Its role as an oncogene has been described by modulating different cancer pathways through its methyltransferase activity, or the short isoform of the protein, through protein interactions. Specifically, in this review we will focus on the functions that have been characterized as methyltransferase dependent, and those that have been correlated with the expression of the NSD3S isoform. There is evidence that both the NSD3L and NSD3S isoforms are relevant for cancer progression, establishing NSD3 as a therapeutic target. However, further functional studies are needed to differentiate NSD3 oncogenic activity as dependent or independent of the catalytic domain of the protein, as well as the contribution of each isoform and its clinical significance in cancer progression.

Drug Discovery Targeting Nuclear Receptor Binding SET Domain Protein 2 (NSD2)

Nuclear receptor binding SET domain proteins (NSDs) catalyze the mono- or dimethylation of histone 3 lysine 36 (H3K36me1 and H3K36me2), using S-adenosyl-l-methionine (SAM) as a methyl donor. As a key member of the NSD family of proteins, NSD2 plays an important role in the pathogenesis and progression of various diseases such as cancers, inflammations, and infectious diseases, serving as a promising drug target. Developing potent and specific NSD2 inhibitors may provide potential novel therapeutics. Several NSD2 inhibitors and degraders have been discovered while remaining in the early stage of drug development. Excitingly, KTX-1001, a selective NSD2 inhibitor, has entered clinical trials. In this Perspective, the structures and functions of NSD2, its roles in various human diseases, and the recent advances in drug discovery strategies targeting NSD2 have been summarized. The challenges, opportunities, and future directions for developing NSD2 inhibitors and degraders are also discussed.

Prospect of targeting lysine methyltransferase NSD3 for tumor therapy

Nuclear receptor binding SET domain protein 3 (NSD3) has recently been recognized as a new epigenetic target in the fight against cancer. NSD3, which is amplified, overexpressed or mutated in a variety of tumors, promotes tumor development by regulating the cell cycle, apoptosis, DNA repair and EMT. Therefore, the inhibition, silencing or knockdown of NSD3 are highly promising antitumor strategies. This paper summarizes the structure and biological functions of NSD3 with an emphasis on its carcinogenic or cancer-promoting activity. The development of NSD3-specific inhibitors or degraders is also discussed and reviewed in this paper.

NSD3: Advances in cancer therapeutic potential and inhibitors research

Nuclear receptor-binding SET domain 3, otherwise known as NSD3, is a member of the group of lysine methyltransferases and is involved in a variety of cellular processes, including transcriptional regulation, DNA damage repair, non-histone related functions and several others. NSD3 gene is mutated or loss of function in a variety of cancers, including breast, lung, pancreatic, and osteosarcoma. These mutations produce dysfunction of the corresponding tumor tissue proteins, leading to tumorigenesis, progression, chemoresistance, and unfavorable prognosis, which suggests that the development of NSD3 probe molecules is important for understanding the specific role of NSD3 in disease and drug discovery. In recent years, NSD3 has been increasingly reported, demonstrating that this target is a very hot epigenetic target. However, the number of NSD3 inhibitors available for cancer therapy is limited and none of the drugs that target NSD3 are currently available on the market. In addition, there are very few reviews describing NSD3. Within this review, we highlight the role of NSD3 in tumorigenesis and the development of NSD3 targeted small-molecule inhibitors over the last decade. We hope that this publication can serve as a guide for the development of potential drug candidates for various diseases in the field of epigenetics, especially for the NSD3 target.

Understanding the Roles of the NSD Protein Methyltransferases in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent non-skin cancer in the world. While immunotherapy has revolutionized the standard of care treatment in patients with recurrent/metastatic HNSCC, more than 70% of patients do not respond to this treatment, making the identification of novel therapeutic targets urgent. Recently, research endeavors have focused on how epigenetic modifications may affect tumor initiation and progression of HNSCC. The nuclear receptor binding SET domain (NSD) family of protein methyltransferases NSD1-NSD3 is of particular interest for HNSCC, with NSD1 and NSD3 being amongst the most commonly mutated or amplified genes respectively in HNSCC. Preclinical studies have identified both oncogenic and tumor-suppressing properties across NSD1, NSD2, and NSD3 within the context of HNSCC. The purpose of this review is to provide a better understanding of the contribution of the NSD family of protein methyltransferases to the pathogenesis of HNSCC, underscoring their promise as novel therapeutic targets in this devastating disease.

NEK7: a new target for the treatment of multiple tumors and chronic inflammatory diseases

NIMA-related kinase 7 (NEK7) is a serine/threonine kinase, which is the smallest one in mammalian NEK family. At present, many studies have reported that NEK7 has a physiological role in regulating the cell cycle and promoting the mitotic process of cells. In recent years, an increasing number of studies have proposed that NEK7 is involved in the activation of the NLRP3 inflammasome. Under normal conditions, NEK7 is in a low activity state, while under pathological conditions, NEK7 is abnormally expressed and therefore plays a key role in the progression of multiple tumors and chronic inflammatory diseases. This review will concentrate on the mechanism of NEK7 participates in the process of mitosis and regulates the activation of NLRP3 inflammasome, the aberrant expression of NEK7 in a variety of tumors and chronic inflammatory diseases, and some potential inhibitors, which may provide some new ideas for the treatment of diverse tumors and chronic inflammatory diseases associated with NEK7.

Discovery of a potent and selective proteolysis targeting chimera (PROTAC) degrader of NSD3 histone methyltransferase

Nuclear receptor binding SET domain protein 3 (NSD3) is an attractive potential target in the therapy for human cancers. Herein, we report the discovery of a series of small-molecule NSD3 degraders based on the proteolysis targeting chimera (PROTAC) strategy. The represented compound 8 induces NSD3 degradation with DC₅₀ values of 1.43 and 0.94 μM in NCI-H1703 and A549 lung cancer cells, respectively, and shows selectivity over two other NSD proteins. 8 reduces histone H3 lysine 36 methylation and induces apoptosis and cell cycle arrest in lung cancer cells. Moreover, the RNA sequencing and immunohistochemistry assays showed that 8 downregulates NSD3-associated gene expression. Significantly, 8, but not 1 (a reported NSD3-PWWP antagonist) could inhibit the cell growth of NCI-H1703 and A549 cells. A single administration of 8 effectively decreases the NSD3 protein level in lung cancer xenograft models. Therefore, this study demonstrated that inducing NSD3 degradation is a more effective approach inhibiting the function of NSD3 than blocking the NSD3-PWWP domain, which may provide a potential therapeutic approach for lung cancer.

The role of NSD1, NSD2, and NSD3 histone methyltransferases in solid tumors

NSD1, NSD2, and NSD3 constitute the nuclear receptor-binding SET Domain (NSD) family of histone 3 lysine 36 (H3K36) methyltransferases. These structurally similar enzymes mono- and di-methylate H3K36, which contribute to the maintenance of chromatin integrity and regulate the expression of genes that control cell division, apoptosis, DNA repair, and epithelial-mesenchymal transition (EMT). Aberrant expression or mutation of members of the NSD family is associated with developmental defects and the occurrence of some types of cancer. In this review, we discuss the effect of alterations in NSDs on cancer patient's prognosis and response to treatment. We summarize the current understanding of the biological functions of NSD proteins, focusing on their activities and the role in the formation and progression in solid tumors biology, as well as how it depends on tumor etiologies. This review also discusses ongoing efforts to develop NSD inhibitors as a promising new class of cancer therapeutic agents.

Targeting the Nuclear Receptor-Binding SET Domain Family of Histone Lysine Methyltransferases for Cancer Therapy: Recent Progress and Perspectives

Nuclear receptor-binding SET domain (NSD) proteins are a class of histone lysine methyltransferases (HKMTases) that are amplified, mutated, translocated, or overexpressed in various types of cancers. Several campaigns to develop NSD inhibitors for cancer treatment have begun following recent advances in knowledge of NSD1, NSD2, and NSD3 structures and functions as well as the U.S. FDA approval of the first HKMTase inhibitor (tazemetostat, an EZH2 inhibitor) to treat follicular lymphoma and epithelioid sarcoma. This perspective highlights recent findings on the structures of catalytic su(var), enhancer-of-zeste, trithorax (SET) domains and other functional domains of NSD methyltransferases. In addition, recent progress and efforts to discover NSD-specific small molecule inhibitors against cancer-targeting catalytic SET domains, plant homeodomains, and proline-tryptophan-tryptophan-proline domains are summarized.

Structure, Activity and Function of the NSD3 Protein Lysine Methyltransferase

NSD3 is one of six H3K36-specific lysine methyltransferases in metazoans, and the methylation of H3K36 is associated with active transcription. NSD3 is a member of the nuclear receptor-binding SET domain (NSD) family of histone methyltransferases together with NSD1 and NSD2, which generate mono- and dimethylated lysine on histone H3. NSD3 is mutated and hyperactive in some human cancers, but the biochemical mechanisms underlying such dysregulation are barely understood. In this review, the current knowledge of NSD3 is systematically reviewed. Finally, the molecular and functional characteristics of NSD3 in different tumor types according to the current research are summarized.

Histone and DNA binding ability studies of the NSD subfamily of PWWP domains

The NSD proteins, namely NSD1, NSD2 and NSD3, are lysine methyltransferases, which catalyze mono- and di-methylation of histone H3K36. They are multi-domain proteins, including two PWWP domains (PWWP1 and PWWP2) separated by some other domains. These proteins act as potent oncoproteins and are implicated in various cancers. However the biological functions of these PWWP domains are still largely unknown. To better understand the functions of these proteins' PWWP domains, we cloned, expressed and purified all the PWWP domains of these NSD proteins to characterize their interactions with methylated histone peptides and dsDNA by quantitative binding assays and crystallographic analysis. Our studies indicate that all these PWWP domains except NSD1_PWWP1 bind to trimethylated H3K36, H3K79 peptides and dsDNA weakly. Our crystal structures uncover that the NDS3_PWWP2 and NSD2_PWWP1 domains, which hold an extremely long α-helix and α-helix bundle, respectively, need a conformation adjustment to interact with nucleosome.

High WHSC1L1 Expression Reduces Survival Rates in Operated Breast Cancer Patients with Decreased CD8+ T Cells: Machine Learning Approach

Nuclear receptor-binding SET domain protein (NSD), a histone methyltransferase, is known to play an important role in cancer pathogenesis. The WHSC1L1 (Wolf-Hirschhorn syndrome candidate 1-like 1) gene, encoding NSD3, is highly expressed in breast cancer, but its role in the development of breast cancer is still unknown. The purpose of this study was to analyze the survival rates and immune responses of breast cancer patients with high WHSC1L1 expression and to validate the results using gradient boosting machine (GBM) in breast cancer. We investigated the clinicopathologic parameters, proportions of immune cells, pathway networks and in vitro drug responses according to WHSC1L1 expression in 456, 1500 and 776 breast cancer patients from the Hanyang University Guri Hospital, METABRIC and TCGA, respectively. High WHSC1L1 expression was associated with poor prognosis, decreased CD8+ T cells and high CD274 expression (encoding PD-L1). In the pathway networks, WHSC1L1 was indirectly linked to the regulation of the lymphocyte apoptotic process. The GBM model with WHSC1L1 showed improved prognostic performance compared with the model without WHSC1L1. We found that VX-11e, CZC24832, LY2109761, oxaliplatin and erlotinib were effective in inhibiting breast cancer cell lines with high WHSC1L1 expression. High WHSC1L1 expression could play potential roles in the progression of breast cancer and targeting WHSC1L1 could be a potential strategy for the treatment of breast cancer.

Physiological and Pathological Roles of Mammalian NEK7

NEK7 is the smallest NIMA-related kinase (NEK) in mammals. The pathological and physiological roles of NEK7 have been widely reported in many studies. To date, the major function of NEK7 has been well documented in mitosis and NLRP3 inflammasome activation, but the detailed mechanisms of its regulation remain unclear. This review summarizes current advances in NEK7 research involving mitotic regulation, NLRP3 inflammasome activation, related diseases and potential inhibitors, which may provide new insights into the understanding and therapy of the diseases associated with NEK7, as well as the subsequent studies in the future.

Application of Artificial Intelligence Technology in Oncology: Towards the Establishment of Precision Medicine

In recent years, advances in artificial intelligence (AI) technology have led to the rapid clinical implementation of devices with AI technology in the medical field. More than 60 AI-equipped medical devices have already been approved by the Food and Drug Administration (FDA) in the United States, and the active introduction of AI technology is considered to be an inevitable trend in the future of medicine. In the field of oncology, clinical applications of medical devices using AI technology are already underway, mainly in radiology, and AI technology is expected to be positioned as an important core technology. In particular, "precision medicine," a medical treatment that selects the most appropriate treatment for each patient based on a vast amount of medical data such as genome information, has become a worldwide trend; AI technology is expected to be utilized in the process of extracting truly useful information from a large amount of medical data and applying it to diagnosis and treatment. In this review, we would like to introduce the history of AI technology and the current state of medical AI, especially in the oncology field, as well as discuss the possibilities and challenges of AI technology in the medical field.

NSD3-Induced Methylation of H3K36 Activates NOTCH Signaling to Drive Breast Tumor Initiation and Metastatic Progression

Histone methyltransferase NSD3 is frequently dysregulated in human cancers, yet the epigenetic role of NSD3 during cancer development remains elusive. Here we report that NSD3-induced methylation of H3K36 is crucial for breast tumor initiation and metastasis. In patients with breast cancer, elevated expression of NSD3 was associated with recurrence, distant metastasis, and poor survival. In vivo, NSD3 promoted malignant transformation of mammary epithelial cells, a function comparable to that of HRAS. Furthermore, NSD3 expanded breast cancer-initiating cells and promoted epithelial-mesenchymal transition to trigger tumor invasion and metastasis. Mechanistically, the long isoform (full-length transcript) of NSD3, but not its shorter isoform lacking a catalytic domain, cooperated with EZH2 and RNA polymerase II to stimulate H3K36me2/3-dependent transactivation of genes associated with NOTCH receptor cleavage, leading to nuclear accumulation of NICD and NICD-mediated transcriptional repression of E-cadherin. Furthermore, mice harboring primary and metastatic breast tumors with overexpressed NSD3 showed sensitivity to NOTCH inhibition. Together, our findings uncover the critical epigenetic role of NSD3 in the modulation of NOTCH-dependent breast tumor progression, providing a rationale for targeting the NSD3-NOTCH signaling regulatory axis in aggressive breast cancer. SIGNIFICANCE: This study demonstrates the functional significance of histone methyltransferase NSD3 in epigenetic regulation of breast cancer stemness, EMT, and metastasis, suggesting NSD3 as an actionable therapeutic target in metastatic breast cancer.

Computational analyses on genetic alterations in the NSD genes family and the implications for colorectal cancer development

Colorectal cancer (CRC) is a prevalent tumour throughout the world. CRC symptoms appear only in advanced stages causing decrease in survival of patients. Therefore, it is necessary to establish new strategies to detect CRC through subclinical screening. Genetic alterations and differential expression of genes that codify histone methyltransferases (HMTs) are linked to tumourigenesis of CRC. One important group of genes that codify HMTs are the NSD family composed of NSD1, NSD2 and NSD3 genes. This family participates in several cancer processes as oncogenes, harbouring several genetic alterations and presenting differential expression in tumour cells. To investigate the implications of NSD genes in CRC cancer, we described the genomic landscape of all NSD family members in a cohort of CRC patients from publicly available cancer datasets. We identified associations among recurrent copy number alterations (CNAs), mutations and differential gene expression concerning clinical outcome. We found in CRC repositories that NSD1 harbours a missense mutation in SET domain—the catalytic region—that probably could decrease its activity. In addition, we found an association between the low expressions of NSD1 and NSD2 and decrease of survival probability in CRC patients. Finally, we reported that NSD3 showed the highest rate of gene amplification, which was highly correlated to its mRNA expression, a common feature of many cancer drivers. Our results highlight the potential use of the NSD1 and NSD2 gene as prognostic markers of poor prognosis in CRC patients. Additionally, we appointed the use of the NSD3 gene as a putative cancer driver gene in CRC given that this gene harbours the highest rate of genetic amplification. All our findings are leading to novel strategies to predict and control CRC, however, some studies need to be conducted to validate these findings.

Epigenetics Analysis and Integrated Analysis of Multiomics Data, Including Epigenetic Data, Using Artificial Intelligence in the Era of Precision Medicine

To clarify the mechanisms of diseases, such as cancer, studies analyzing genetic mutations have been actively conducted for a long time, and a large number of achievements have already been reported. Indeed, genomic medicine is considered the core discipline of precision medicine, and currently, the clinical application of cutting-edge genomic medicine aimed at improving the prevention, diagnosis and treatment of a wide range of diseases is promoted. However, although the Human Genome Project was completed in 2003 and large-scale genetic analyses have since been accomplished worldwide with the development of next-generation sequencing (NGS), explaining the mechanism of disease onset only using genetic variation has been recognized as difficult. Meanwhile, the importance of epigenetics, which describes inheritance by mechanisms other than the genomic DNA sequence, has recently attracted attention, and, in particular, many studies have reported the involvement of epigenetic deregulation in human cancer. So far, given that genetic and epigenetic studies tend to be accomplished independently, physiological relationships between genetics and epigenetics in diseases remain almost unknown. Since this situation may be a disadvantage to developing precision medicine, the integrated understanding of genetic variation and epigenetic deregulation appears to be now critical. Importantly, the current progress of artificial intelligence (AI) technologies, such as machine learning and deep learning, is remarkable and enables multimodal analyses of big omics data. In this regard, it is important to develop a platform that can conduct multimodal analysis of medical big data using AI as this may accelerate the realization of precision medicine. In this review, we discuss the importance of genome-wide epigenetic and multiomics analyses using AI in the era of precision medicine.

Deregulation of the Histone Lysine-Specific Demethylase 1 Is Involved in Human Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and is a leading cause of cancer-related death worldwide. Given that the standard-of-care for advanced liver cancer is limited, there is an urgent need to develop a novel molecular targeted therapy to improve therapeutic outcomes for HCC. In order to tackle this issue, we conducted functional analysis of the histone lysine-specific demethylase (LSD1) to explore the possibility that this enzyme acts as a therapeutic target in HCC. According to immunohistochemical analysis, 232 of 303 (77%) HCC cases showed positive staining of LSD1 protein, and its expression was correlated with several clinicopathological characteristics, such as female gender, AFP (alpha-fetoprotein) levels, and HCV (hepatitis C virus) infectious. The survival curves for HCC using the Kaplan–Meier method and the log-rank test indicate that positive LSD1 protein expression was significantly associated with decreased rates of overall survival (OS) and disease-free survival (DFS); the multivariate analysis indicates that LSD1 expression was an independent prognostic factor for both OS and DFS in patients with HCC. In addition, knockout of LSD1 using the CRISPR/Cas9 system showed a significantly lower number of colony formation units (CFUs) and growth rate in both SNU-423 and SNU-475 HCC cell lines compared to the corresponding control cells. Moreover, LSD1 knockout decreased cells in S phase of SNU-423 and SNU-475 cells with increased levels of H3K4me1/2 and H3K9me1/2. Finally, we identified the signaling pathways regulated by LSD1 in HCC, including the retinoic acid (RA) pathway. Our findings imply that deregulation of LSD1 can be involved in HCC; further studies may explore the usefulness of LSD1 as a therapeutic target of HCC.

High yield recombinant expression and purification of oncogenic NSD1, NSD2, and NSD3 with human influenza hemagglutinin tag

The nuclear receptor-binding SET Domain (NSD) family consists of NSD1, NSD2/MMSET/WHSC1, and NSD3/WHSC1L1 histone methyltransferases that are crucial for chromatin remodeling. NSDs are implicated in developmental disorders such as Wolf-Hirschhorn and Sotos syndromes as well as various cancers including t(4; 14)(p16; q32) myeloma, an incurable cancer in plasma cells. NSDs have been the target of intensive study to understand their biological functions more fully and inform anti-cancer drug design. Recombinant protein expression and purification of human NSDs using an E. coli expression system are notoriously challenging, but the production of pure, stable, and active NSDs is essential for further studies. To overcome production challenges, we propose a cost-efficient approach optimized to produce a high yield of NSDs using a modified E. coli expression system. We found that tagging the NSDs with a human influenza hemagglutinin (HA) tag greatly improved the quality of the recombinant NSDs, resulting in more than 95% pure, stable, and active NSD-HAs, with an increase in production yield up to 22.4-fold and up to 6.25 mg/L from LB E. coli culture, and without further purification such as ion-exchange or size-exclusion chromatography.

Fragment-based discovery of a chemical probe for the PWWP1 domain of NSD3

Here, we report the fragment-based discovery of BI-9321, a potent, selective and cellular active antagonist of the NSD3-PWWP1 domain. The human NSD3 protein is encoded by the WHSC1L1 gene located in the 8p11-p12 amplicon, frequently amplified in breast and squamous lung cancer. Recently, it was demonstrated that the PWWP1 domain of NSD3 is required for the viability of acute myeloid leukemia cells. To further elucidate the relevance of NSD3 in cancer biology, we developed a chemical probe, BI-9321, targeting the methyl-lysine binding site of the PWWP1 domain with sub-micromolar in vitro activity and cellular target engagement at 1 µM. As a single agent, BI-9321 downregulates Myc messenger RNA expression and reduces proliferation in MOLM-13 cells. This first-in-class chemical probe BI-9321, together with the negative control BI-9466, will greatly facilitate the elucidation of the underexplored biological function of PWWP domains.

Downregulation of NSD3 (WHSC1L1) inhibits cell proliferation and migration via ERK1/2 deactivation and decreasing CAPG expression in colorectal cancer cells

Purpose: NSD3 (WHSC1L1) is a protein lysine methyltransferase that is recurrently amplified (8p11.23) in several cancer types, and its upregulation is involved in tumor cell proliferation, metastasis, and epithelial-mesenchymal transition (EMT). We aimed to evaluate its potential function as an oncogenic force in colorectal cancer (CRC), and to elucidate relevant mechanisms of its oncogenic activity. Materials and methods: NSD3 levels were analyzed in human CRC and adjacent normal tissues or cells by Western blot analysis and RT-qPCR. Expression levels of the proteins were detected by Western blot analysis and RT-qPCR. Results: NSD3 was significantly upregulated in both CRC tissues and cell lines. Knockdown of NSD3 expression resulted in significant decreases in CRC cell proliferation, migration, and EMT process marker proteins vimentin, simultaneously reducing E-cadherin and N-cadherin expression. The opposite results were observed when NSD3 was overexpressed. Additionally, overexpressing of NSD3 dramatically activated the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway and enhanced actin-capping protein (CAPG) expression. Furthermore, the proliferation and migration abilities evidently facilitated by pcDNA3.1(+) expression vector containing full-length CDS of NSD3 (pcDNA3.1(+)-NSD3, or NSD3) were partially decreased after incubation with ERK1/2 signaling pathway inhibitor (PD98059) and/or specific siRNA against CAPG (siCAPG) in SW480 and HT-29 CRC cells. Conclusion: NSD3 overexpression stimulated CRC cell proliferation and migration through targeting the ERK1/2 signaling pathway and downstream CAPG. Thus, NSD3 could serve as a promising target for anticancer drug development for patients with CRC.

Pathogenic and Therapeutic Role of H3K4 Family of Methylases and Demethylases in Cancers

Histone modifications occupy an essential position in the epigenetic landscape of the cell, and their alterations have been linked to cancers. Histone 3 lysine 4 (H3K4) methylation has emerged as a critical epigenetic cue for the regulation of gene transcription through dynamic modulation by several H3K4 methyltransferases (writers) and demethylases (erasers). Any disturbance in the delicate balance of writers and erasers can result in the mis-regulation of H3K4 methylation, which has been demonstrated in several human cancers. Therefore, H3K4 methylation has been recognized as a putative therapeutic or prognostic tool and drug trials of different inhibitors of this process have demonstrated promising results. Henceforth, more detailed knowledge of H3K4 methylation is utmost important for elucidating the complex cellular processes, which might help in improving the disease outcome. The primary focus of this review will be directed on deciphering the role of H3K4 methylation along with its writers/erasers in different cancers.

Analysis of the role of mutations in the KMT2D histone lysine methyltransferase in bladder cancer

Histone lysine methyltransferases (HMT) comprise a subclass of epigenetic regulators; dysregulation of these enzymes affects gene expression, which may lead to tumorigenesis. Here, we performed an integrated analysis of 50 HMTs in bladder cancer and found intrinsic links between copy number alterations, mutations, gene expression levels, and clinical outcomes. Through integrative analysis, we identified six HMT genes (PRDM9,ASH1L,SETD3,SETD5,WHSC1L1, and KMT2D) that may play a key role in the development and progression of bladder cancer. Of these six HMTs, histone lysine N‐methyltransferase 2D (KMT2D) exhibited the highest mutation rate in bladder cancer. Our comparison of the mRNA and miRNA expression profiles of mutated and wild‐type KMT2D suggested that two signaling pathways (FOX1–miR‐1224‐5p–DLK1 and HIF/GATA5–miR‐133a‐3p–DRD5) may mediate the tumor suppressive effect of the KMT2D mutation. In summary, our findings indicate that mutations in HMT genes, especially KMT2D mutation, may play a role in the development of bladder cancer.

Retracted Article: CircRNA PVT1 modulates cell metastasis via the miR-181a-5p/NEK7 axis and cisplatin chemoresistance through miR-181a-5p-mediated autophagy in non-small cell lung cancer

In the initiation and evolution of human cancers, circular RNAs (circRNAs) act as crucial regulators. The aim of this report was to ascertain the functional mechanisms of circRNA plasmacytoma variant translocation 1 (circPVT1) in the metastasis and chemoresistance of non-small cell lung cancer (NSCLC). The levels of circPVT1, microRNA-181a-5p (miR-181a-5p) and non-inherited maternal antigens-related kinase 7 (NEK7) were examined via quantitative real-time polymerase chain reaction (qRT-PCR). The levels of the associated proteins were determined through western blot. Cell counting kit-8 (CCK-8) and flow cytometry were used to assess the half inhibitory concentration (IC₅₀) of cisplatin and cell apoptosis, respectively. Cell invasion was detected by transwell assay. A dual-luciferase reporter assay and RNA immunoprecipitation (RIP) were used to confirm the target relation. The impact of circPVT1 on cisplatin chemoresistance in vivo was investigated using xenograft experiments. CircPVT1 and NEK7 were up-regulated and miR-181a-5p was down-regulated in NSCLC. CircPVT1 knockdown refrained the cisplatin chemoresistance and metastasis of NSCLC cells. MiR-181a-5p was a target of circPVT1 and circPVT1 inhibition alleviated the effects of a miR-181a-5p inhibitor on NSCLC cells. The decrease of circPVT1 accentuated the si-NEK7-inhibited metastasis by the miR-181a-5p/NEK7 axis and relieved the 3-methyladenine (3-MA)-promoted cisplatin chemoresistance by miR-181a-5p-mediated autophagy. Down-regulation of circPVT1 facilitated the cisplatin sensitivity of NSCLC cells in vivo. Due to the modulation of cell metastasis via the miR-181a-5p/NEK7 axis and cisplatin chemoresistance by miR-181a-5p-mediated autophagy in NSCLC, circPVT1 might act as an appreciable therapeutic marker for NSCLC.

In the initiation and evolution of human cancers, circular RNAs (circRNAs) act as crucial regulators.

Overexpression of KDM5B/JARID1B is associated with poor prognosis in hepatocellular carcinoma

Background & aims

Hepatocellular carcinoma (HCC) has high potential for recurrence, even in curative operative cases. Although several molecular-targeting drugs have been applied to recurrent HCC, their effectiveness has been limited. This study therefore aims to develop novel cancer drugs through protein methylation.

Methods

We investigated the role of KDM5B/JARID1B, a member of JmjC histone demethylase, in HCC. Expression profiles of KDM5B were examined by immunohistochemical analysis in 105 HCC clinical tissue samples. To examine functional effects of KDM5B using HCC cell lines, we performed loss-of-function analysis treated with KDM5B-specific small interfering RNAs (siKDM5B).

Results

All HCC cases were divided into KDM5B-positive expression group (n=54) and negative expression group (n=51). In five-year overall survival, KDM5B-positive group had poorer prognosis than KDM5B-negative (61% vs 77%, p=0.047). KDM5B-positive group had much poorer prognosis than that of the negative group, especially in HCC derived from persistent infection of hepatitis B virus (HBV) or hepatitis C virus (HCV) (54% vs 78%, p=0.015). Multivariate analysis indicated that KDM5B was the strongest risk factor for poor prognosis, especially in HCC derived from HBV/HCV. Inhibition of KDM5B could significantly suppress HCC cell proliferation through no promotion from G1 to S phase. Real-time PCR and Western blotting demonstrated that E2F1/E2F2 were downstream genes of KDM5B.

Conclusions

Overexpression of KDM5B results in poor prognosis in HCC that especially derived from HBV/HCV. KDM5B appears to be an ideal target for the development of anti-cancer drugs.

The role of histone lysine methyltransferase NSD3 in cancer

The growing number of findings demonstrate that nuclear receptor suppressor of variegation, enhancer of zeste, and trithorax domain-containing 3 (NSD3) is amplified and overexpressed in multiple cancer types. Nevertheless, the biological roles of NSD3 in carcinogenesis have not been well understood. In this review, we summarize the current knowledge on the mechanisms underlying NSD3 regulation in different cancers. In addition, NSD3 may serve as a potential druggable target for selective cancer therapy in the future.

Lung Cancer Therapy Targeting Histone Methylation: Opportunities and Challenges

Lung cancer is one of the most common malignancies. In spite of the progress made in past decades, further studies to improve current therapy for lung cancer are required. Dynamically controlled by methyltransferases and demethylases, methylation of lysine and arginine residues on histone proteins regulates chromatin organization and thereby gene transcription. Aberrant alterations of histone methylation have been demonstrated to be associated with the progress of multiple cancers including lung cancer. Inhibitors of methyltransferases and demethylases have exhibited anti-tumor activities in lung cancer, and multiple lead candidates are under clinical trials. Here, we summarize how histone methylation functions in lung cancer, highlighting most recent progresses in small molecular inhibitors for lung cancer treatment.

Genome-wide multi-omics profiling of the 8p11-p12 amplicon in breast carcinoma

Genomic instability contributes to the neoplastic phenotype by deregulating key cancer-related genes, which in turn can have a detrimental effect on patient outcome. DNA amplification of the 8p11-p12 genomic region has clinical and biological implications in multiple malignancies, including breast carcinoma where the amplicon has been associated with tumor progression and poor prognosis. However, oncogenes driving increased cancer-related death and recurrent genetic features associated with the 8p11-p12 amplicon remain to be identified. In this study, DNA copy number and transcriptome profiling data for 229 primary invasive breast carcinomas (corresponding to 185 patients) were evaluated in conjunction with clinicopathological features to identify putative oncogenes in 8p11-p12 amplified samples. Illumina paired-end whole transcriptome sequencing and whole-genome SNP genotyping were subsequently performed on 23 samples showing high-level regional 8p11-p12 amplification to characterize recurrent genetic variants (SNPs and indels), expressed gene fusions, gene expression profiles and allelic imbalances. We now show previously undescribed chromothripsis-like patterns spanning the 8p11-p12 genomic region and allele-specific DNA amplification events. In addition, recurrent amplification-specific genetic features were identified, including genetic variants in the HIST1H1E and UQCRHL genes and fusion transcripts containing MALAT1 non-coding RNA, which is known to be a prognostic indicator for breast cancer and stimulated by estrogen. In summary, these findings highlight novel candidate targets for improved treatment of 8p11-p12 amplified breast carcinomas.

The role of protein methyltransferases as potential novel therapeutic targets in squamous cell carcinoma of the head and neck

Squamous cell carcinoma of the head and neck is a lethal disease with suboptimal survival outcomes and standard therapies with significant comorbidities. Whole exome sequencing data recently revealed an abundance of genetic and expression alterations in a family of enzymes known as protein methyltransferases in a variety of cancer types, including squamous cell carcinoma of the head and neck. These enzymes are mostly known for their chromatin-modifying functions through methylation of various histone substrates, though evidence supports their function also through methylation of non-histone substrates. This review summarizes the current knowledge on the function of protein methyltransferases in squamous cell carcinoma of the head and neck and highlights their promising potential as the next generation of therapeutic targets in this disease.

SMYD3-mediated lysine methylation in the PH domain is critical for activation of AKT1

AKT1 is a cytosolic serine/threonine kinase that is overexpressed in various types of cancer and has a central role in human tumorigenesis. Although it is known that AKT1 is post-translationally modified in various ways including phosphorylation and ubiquitination, methylation has not been reported so far. Here we demonstrate that the protein lysine methyltransferase SMYD3 methylates lysine 14 in the PH domain of AKT1 both in vitro and in vivo. Lysine 14-substituted AKT1 shows significantly lower levels of phosphorylation at threonine 308 than wild-type AKT1, and knockdown of SMYD3 as well as treatment with a SMYD3 inhibitor significantly attenuates this phosphorylation in cancer cells. Furthermore, substitution of lysine 14 diminishes the plasma membrane accumulation of AKT1, and cancer cells overexpressing lysine 14-substiuted AKT1 shows lower growth rate than those overexpressing wild-type AKT1. These results imply that SMYD3-mediated methylation of AKT1 at lysine 14 is essential for AKT1 activation and that SMYD3-mediated AKT1 methylation appears to be a good target for development of anti-cancer therapy.

WHSC1L1 drives cell cycle progression through transcriptional regulation of CDC6 and CDK2 in squamous cell carcinoma of the head and neck

Wolf-Hisrchhorn Syndrome Candidate 1-Like 1 (WHSC1L1) is a protein lysine methyltransferase that is recurrently amplified (8p11.23) in patients with squamous cell carcinoma of the head and neck (SCCHN). In this study, we investigated the oncogenic role of WHSC1L1 in SCCHN. Using immunohistochemistry on tissue microarrays of patients with locoregionally advanced SCCHN, we found that WHSC1L1 is significantly overexpressed in patients with SCCHN, and is associated with poor grade and heavy smoking history. Knockdown of WHSC1L1 expression resulted in significant growth suppression and reduction of H3K36 dimethylation (H3K36me2) in SCCHN cells. Chromatin immunoprecipitation analysis showed that WHSC1L1 and H3K36me2 are enriched in the gene bodies of the cell cycle-related genes CDC6 and CDK2, implying that WHSC1L1 directly regulates the transcription of these genes. According to the importance of CDC6 and CDK2 for G1 to S transition, WHSC1L1 knockdown induced strong G0/G1 arrest which was rescued by introduction of wild-type WHSC1L1 but not by that of enzyme-inactive WHSC1L1. Our results imply that WHSC1L1 and its product H3K36me2 are essential for the transition from G1 to S phase in SCCHN cells and that WHSC1L1 could serve as a rational target for anticancer drug development for patients with head and neck cancer.

Automethylation of SUV39H2, an oncogenic histone lysine methyltransferase, regulates its binding affinity to substrate proteins

We previously reported that the histone lysine methyltransferase SUV39H2, which is overexpressed in various types of human cancer, plays a critical role in the DNA repair after double strand breakage, and possesses oncogenic activity. Although its biological significance in tumorigenesis has been elucidated, the regulatory mechanism of SUV39H2 activity through post-translational modification is not well known. In this study, we demonstrate in vitro and in vivo automethylation of SUV39H2 at lysine 392. Automethylation of SUV39H2 led to impairment of its binding affinity to substrate proteins such as histone H3 and LSD1. Furthermore, we observed that hyper-automethylated SUV39H2 reduced methylation activities to substrates through affecting the binding affinity to substrate proteins. Our finding unveils a novel autoregulatory mechanism of SUV39H2 through lysine automethylation.

The methyltransferase NSD3 promotes antiviral innate immunity via direct lysine methylation of IRF3

Lysine methylation is an important posttranslational modification, implicated in various biological pathological conditions. The transcription factor interferon regulatory factor 3 (IRF3) is essential for antiviral innate immunity, yet the mechanism for methylation control of IRF3 activation remains unclear. In this paper, we discovered monomethylation of IRF3 at K366 is critical for IRF3 transcription activity in antiviral innate immunity. By mass spectrometry analysis of IRF3-associated proteins, we identified nuclear receptor-binding SET domain 3 (NSD3) as the lysine methyltransferase that directly binds to the IRF3 C-terminal region through its PWWP1 domain and methylates IRF3 at K366 via its SET domain. Deficiency of NSD3 impairs the antiviral innate immune response in vivo. Mechanistically, NSD3 enhances the transcription activity of IRF3 dependent on K366 monomethylation, which maintains IRF3 phosphorylation by promoting IRF3 dissociation of protein phosphatase PP1cc and consequently promotes type I interferon production. Our study reveals a critical role of NSD3-mediated IRF3 methylation in enhancing antiviral innate immunity.

Silencing of histone methyltransferase NSD3 reduces cell viability in osteosarcoma with induction of apoptosis

NSD3 is a histone lysine methyltransferase that methylates histone H3 at lysine 36. NSD3 is located at chromosome 8p11.23, the locus that exhibits strong cancer relevance. Thus, NSD3 is likely involved in multiple human cancers. Nevertheless, its roles in human carcinogenesis remain unknown. In the present study, we demonstrated that silencing of NSD3 in osteosarcoma, the most common primary bone cancer in children and adolescents, results in a marked decrease in the number of viable cancer cells, accompanied by increases in the cell population at the G2/M phase and the number of apoptotic cells. In addition, 549 NSD3‑regulated genes were identified and a set of selected candidate genes were validated. Bioinformatic analysis revealed that NSD3 negatively regulates a number of genes that are involved in the process of negative regulation of signal transduction as well as negative regulation of signaling and cell communication. Our results indicate the oncogenic roles of NSD3 in the development and progression of human osteosarcoma, and implicate NSD3 as a potential molecular target for selective therapy for human osteosarcoma.

The Role of Nuclear Receptor-Binding SET Domain Family Histone Lysine Methyltransferases in Cancer

The nuclear receptor-binding SET Domain (NSD) family of histone H3 lysine 36 methyltransferases is comprised of NSD1, NSD2 (MMSET/WHSC1), and NSD3 (WHSC1L1). These enzymes recognize and catalyze methylation of histone lysine marks to regulate chromatin integrity and gene expression. The growing number of reports demonstrating that alterations or translocations of these genes fundamentally affect cell growth and differentiation leading to developmental defects illustrates the importance of this family. In addition, overexpression, gain of function somatic mutations, and translocations of NSDs are associated with human cancer and can trigger cellular transformation in model systems. Here we review the functions of NSD family members and the accumulating evidence that these proteins play key roles in tumorigenesis. Because epigenetic therapy is an important emerging anticancer strategy, understanding the function of NSD family members may lead to the development of novel therapies.

WHSC1L1-mediated EGFR mono-methylation enhances the cytoplasmic and nuclear oncogenic activity of EGFR in head and neck cancer

While multiple post-translational modifications have been reported to regulate the function of epidermal growth factor receptor (EGFR), the effect of protein methylation on its function has not been well characterized. In this study, we show that WHSC1L1 mono-methylates lysine 721 in the tyrosine kinase domain of EGFR, and that this methylation leads to enhanced activation of its downstream ERK cascade without EGF stimulation. We also show that EGFR K721 mono-methylation not only affects the function of cytoplasmic EGFR, but also that of nuclear EGFR. WHSC1L1-mediated methylation of EGFR in the nucleus enhanced its interaction with PCNA in squamous cell carcinoma of the head and neck (SCCHN) cells and resulted in enhanced DNA synthesis and cell cycle progression. Overall, our study demonstrates the multifaceted oncogenic function of the protein lysine methyltransferase WHSC1L1 in SCCHN, which is mediated through direct non-histone methylation of the EGFR protein with effects both in its cytoplasmic and nuclear functions.

SUV420H1 enhances the phosphorylation and transcription of ERK1 in cancer cells

The oncogenic protein ERK, a member of the extracellular signal-regulated kinase (ERK) cascade, is a well characterized signaling molecule involved in tumorigenesis. The ERK signaling pathway is activated in a large proportion of cancers and plays a critical role in tumor development. Functional regulation by phosphorylation of kinases in the ERK pathway has been extensively studied, however methylation of the ERK protein has not been reported to date. Here, we demonstrated that the protein lysine methyltransferase SUV420H1 tri-methylated ERK1 at lysines 302 and 361, and that substitution of methylation sites diminished phosphorylation levels of ERK1. Concordantly, knockdown of SUV420H1 reduced phosphorylated ERK1 and total ERK1 proteins, and interestingly suppressed ERK1 at the transcriptional level. Our results indicate that overexpression of SUV420H1 may result in activation of the ERK signaling pathway through enhancement of ERK phosphorylation and transcription, thereby providing new insights in the regulation of the ERK cascade in human cancer.

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.

PRMT6 increases cytoplasmic localization of p21CDKN1A in cancer cells through arginine methylation and makes more resistant to cytotoxic agents

p21^CDKN1A is known as a potent inhibitor of cyclin-dependent kinase (CDK), which regulates cell cycle in response to various stimuli, including DNA damage, on the p53-dependent manner. Here we demonstrate that protein arginine methyltransferase 6 (PRMT6) methylates p21 at arginine 156 and promotes phosphorylation of threonine 145 on p21, resulting in the increase of cytoplasmic localization of p21. The cytoplasmic presence of p21 makes cancer cells more resistant to cytotoxic agents. Our results indicate that PRMT6 appears to be one of the key proteins to dysregulate p21 functions in human cancer, and targeting this pathway may be an appropriate strategy for development of anticancer drugs.

Histone Modifications and Cancer

Histone posttranslational modifications represent a versatile set of epigenetic marks involved not only in dynamic cellular processes, such as transcription and DNA repair, but also in the stable maintenance of repressive chromatin. In this article, we review many of the key and newly identified histone modifications known to be deregulated in cancer and how this impacts function. The latter part of the article addresses the challenges and current status of the epigenetic drug development process as it applies to cancer therapeutics.

Dysregulation of protein methyltransferases in human cancer: An emerging target class for anticancer therapy

Protein methylation is one of the important post-translational modifications. Although its biological and physiological functions were unknown for a long time, we and others have characterized a number of protein methyltransferases, which have unveiled the critical functions of protein methylation in various cellular processes, in particular, in epigenetic regulation. In addition, it had been believed that protein methylation is an irreversible phenomenon, but through identification of a variety of protein demethylases, protein methylation is now considered to be dynamically regulated similar to protein phosphorylation. A large amount of evidence indicated that protein methylation has a pivotal role in post-translational modification of histone proteins as well as non-histone proteins and is involved in various processes of cancer development and progression. As dysregulation of this modification has been observed frequently in various types of cancer, small-molecule inhibitors targeting protein methyltransferases and demethylases have been actively developed as anticancer drugs; clinical trials for some of these drugs have already begun. In this review, we discuss the biological and physiological importance of protein methylation in human cancer, especially focusing on the significance of protein methyltransferases as emerging targets for anticancer therapy.

Identification of miR-2400 gene as a novel regulator in skeletal muscle satellite cells proliferation by targeting MYOG gene

MicroRNAs play critical roles in skeletal muscle development as well as in regulation of muscle cell proliferation and differentiation. Previous study in our laboratory showed that the expression level of miR-2400, a novel and unique miRNA from bovine, had significantly changed in skeletal muscle-derived satellite cells (MDSCs) during differentiation, however, the function and expression pattern for miR-2400 in MDSCs has not been fully understood. In this report, we firstly identified that the expression levels of miR-2400 were down-regulated during MDSCs differentiation by stem-loop RT-PCR. Over-expression and inhibition studies demonstrated that miR-2400 promoted MDSCs proliferation by EdU (5-ethynyl-2' deoxyuridine) incorporation assay and immunofluorescence staining of Proliferating cell nuclear antigen (PCNA). Luciferase reporter assays showed that miR-2400 directly targeted the 3' untranslated regions (UTRs) of myogenin (MYOG) mRNA. These data suggested that miR-2400 could promote MDSCs proliferation through targeting MYOG. Furthermore, we found that miR-2400, which was located within the eighth intron of the Wolf-Hirschhorn syndrome candidate 1-like 1 (WHSC1L1) gene, was down-regulated in MDSCs in a direct correlation with the WHSC1L1 transcript by Clustered regularly interspaced palindromic repeats interference (CRISPRi). In addition, these observations not only provided supporting evidence for the codependent expression of intronic miRNAs and their host genes in vitro, but also gave insight into the role of miR-2400 in MDSCs proliferation.

The role of Cyclin G1 in cellular proliferation and apoptosis of human epithelial ovarian cancer

Cyclin G1 plays an essential role in the development of human carcinoma. Here, we characterized the clinical significance of Cyclin G1 and investigated its role in cellular proliferation and apoptosis of epithelial ovarian cancer (EOC). Western blot was used to evaluate the expression of Cyclin G1 in nine fresh EOC tissues and three fresh normal ovarian tissues. Immunohistochemistry analysis was performed on formalin-fixed paraffin-embedded section of 119 cases of EOCs. Using cell counting kit (CCK)-8 and colony formation assays, we analyzed the effect of Cyclin G1 in cellular proliferation of EOC. Besides, the immunofluorescence and flow cytometry analysis was performed to study the role of Cyclin G1 in cellular apoptosis of EOC. We found Cyclin G1 was up-regulated in EOC tissues compared with the normal ovary tissues. Cyclin G1 expression in EOC was closely correlated with differentiation grade (P = 0.009) and malignant tumor cells in ascites (P = 0.009). The Kaplan-Meier curve showed that higher expression of Cyclin G1 was associated with significantly shorter survival in EOC patients. Multivariate analysis suggested Cyclin G1 expression was an independent prognostic factor for overall survival. CCK-8 and colony formation assays revealed that depletion of Cyclin G1 inhibited the proliferation and clone formation. Combined immunofluorescence and flow cytometry analysis showed that silencing of Cyclin G1 with shRNA could promote apoptosis of ovarian cancer cells. Additionally, the result of immunoprecipitation test showed Cyclin G1 interacted with CDK2 in EOC cells. In summary, our findings suggest that Cyclin G1 may be involved in the prognosis of EOC patients and be a useful therapeutic target for EOC.

The NSD family of protein methyltransferases in human cancer

The NSD family of protein lysine methyltransferases consists of NSD1, NSD2/WHSC1/MMSET and NSD3/WHSC1L1. NSD2 haploinsufficiency causes Wolf-Hirschhorn syndrome, while NSD1 mutations lead to the Sotos syndrome. Recently, a number of studies showed that the NSD methyltransferases were overexpressed, amplified or somatically mutated in multiple types of cancer, suggesting their critical role in cancer. These enzymes methylate specific lysine residues on histone tails and their dysfunction results in epigenomic aberrations which play a fundamental role in oncogenesis. Furthermore, NSD1 was also reported to methylate a nonhistone protein substrate, RELA/p65 subunit of NF-κB, implying its regulatory function through nonhistone methylation pathways. In this review, we summarize the current research regarding the role of the NSD family proteins in cancer and underline their potential as targets for novel cancer therapeutics.