KDM4 inhibitor SD49-7 attenuates leukemia stem cell via KDM4A/MDM2/p21CIP1 axis

The JMJD family of histone demethylase and their intimate links to cardiovascular disease

The incidence rate and mortality rate of cardiovascular disease rank first in the world. It is associated with various high-risk factors, and there is no single cause. Epigenetic modifications, such as DNA methylation or histone modification, actively participate in the initiation and development of cardiovascular diseases. Histone lysine methylation is a type of histone post-translational modification. The human Jumonji C domain (JMJD) protein family consists of more than 30 members. JMJD proteins participate in many key nuclear processes and play a key role in the specific regulation of gene expression, DNA damage and repair, and DNA replication. Importantly, increasing evidence shows that JMJD proteins are abnormally expressed in cardiovascular diseases, which may be a potential mechanism for the occurrence and development of these diseases. Here, we discuss the key roles of JMJD proteins in various common cardiovascular diseases. This includes histone lysine demethylase, which has been studied in depth, and less-studied JMJD members. Furthermore, we focus on the epigenetic changes induced by each JMJD member, summarize recent research progress, and evaluate their relationship with cardiovascular diseases and therapeutic potential.

The emerging roles of lysine-specific demethylase 4A in cancer: Implications in tumorigenesis and therapeutic opportunities

Lysine-specific demethylase 4 A (KDM4A, also named JMJD2A, KIA0677, or JHDM3A) is a demethylase that can remove methyl groups from histones H3K9me2/3, H3K36me2/3, and H1.4K26me2/me3. Accumulating evidence suggests that KDM4A is not only involved in body homeostasis (such as cell proliferation, migration and differentiation, and tissue development) but also associated with multiple human diseases, especially cancers. Recently, an increasing number of studies have shown that pharmacological inhibition of KDM4A significantly attenuates tumor progression in vitro and in vivo in a range of solid tumors and acute myeloid leukemia. Although there are several reviews on the roles of the KDM4 subfamily in cancer development and therapy, all of them only briefly introduce the roles of KDM4A in cancer without systematically summarizing the specific mechanisms of KDM4A in various physiological and pathological processes, especially in tumorigenesis, which greatly limits advances in the understanding of the roles of KDM4A in a variety of cancers, discovering targeted selective KDM4A inhibitors, and exploring the adaptive profiles of KDM4A antagonists. Herein, we present the structure and functions of KDM4A, simply outline the functions of KDM4A in homeostasis and non-cancer diseases, summarize the role of KDM4A and its distinct target genes in the development of a variety of cancers, systematically classify KDM4A inhibitors, summarize the difficulties encountered in the research of KDM4A and the discovery of related drugs, and provide the corresponding solutions, which would contribute to understanding the recent research trends on KDM4A and advancing the progression of KDM4A as a drug target in cancer therapy.

The role and prospect of lysine-specific demethylases in cancer chemoresistance

Histone methylation plays a key function in modulating gene expression, and preserving genome integrity and epigenetic inheritance. However, aberrations of histone methylation are commonly observed in human diseases, especially cancer. Lysine methylation mediated by histone methyltransferases can be reversed by lysine demethylases (KDMs), which remove methyl marks from histone lysine residues. Currently, drug resistance is a main impediment for cancer therapy. KDMs have been found to mediate drug tolerance of many cancers via altering the metabolic profile of cancer cells, upregulating the ratio of cancer stem cells and drug-tolerant genes, and promoting the epithelial-mesenchymal transition and metastatic ability. Moreover, different cancers show distinct oncogenic addictions for KDMs. The abnormal activation or overexpression of KDMs can alter gene expression signatures to enhance cell survival and drug resistance in cancer cells. In this review, we describe the structural features and functions of KDMs, the KDMs preferences of different cancers, and the mechanisms of drug resistance resulting from KDMs. We then survey KDM inhibitors that have been used for combating drug resistance in cancer, and discuss the opportunities and challenges of KDMs as therapeutic targets for cancer drug resistance.

Development of JmjC-domain-containing histone demethylase (KDM2-7) inhibitors for cancer therapy

Histone methylation is the most common histone modification and a highly dynamic regulator of gene transcription. Methylation of lysine residues can alter the structure of chromatin, helping to regulate DNA-based nuclear activities. Lysine demethylases control and maintain epigenetic factors that affect chromatin structure and cell characteristics. A variety of diseases, including malignant tumors, are connected to their dysregulation. Advances in biochemistry and pathogenesis have prompted the discovery of small molecule inhibitors and tool compounds that disrupt lysine demethylation. In this review, we focus on JmjC-domain-containing histone lysine demethylases (KDM2-7), discussing their structures and biological roles, representative inhibitors, and therapeutic potential in cancer therapy, and aiming to provide unique insights into the development of JmjC-KDM inhibitors.

Human circulating small non-coding RNA signature as a non-invasive biomarker in clinical diagnosis of acute myeloid leukaemia

Background: Acute myeloid leukaemia (AML) is the most common acute leukaemia in adults; AML is highly heterogeneous and involves abnormalities at multiple omics levels. Small non-coding RNAs (sncRNAs) present in body fluids are important regulatory molecules and considered promising non-invasive clinical diagnostic biomarkers for disease. However, the signature of sncRNA profile alteration in AML patient serum and bone marrow supernatant is still under exploration. Methods: We examined data for blood and bone marrow samples from 80 consecutive, newly-diagnosed patients with AML and 12 healthy controls for high throughput small RNA-sequencing. Differentially expressed sncRNAs were analysed to reveal distinct patterns between AML patients and controls. Machine learning methods were used to evaluate the efficiency of specific sncRNAs in discriminating individuals with AML from controls. The altered expression level of individual sncRNAs was evaluated by RT-PCR, Q-PCR, and northern blot. Correlation analysis was employed to assess sncRNA patterns between serum and bone marrow supernatant. Results: We identified over 20 types of sncRNA categories beyond miRNAs in both serum and bone marrow supernatant, with highly coordinated expression patterns between them. Non-classical sncRNAs, including rsRNA (62.86%), ysRNA (14.97%), and tsRNA (4.22%), dominated among serum sncRNAs and showed sensitive alteration patterns in AML patients. According to machine learning-based algorithms, the tsRNA-based signature robustly discriminated subjects with AML from controls and was more reliable than that comprising miRNAs. Our data also showed that serum tsRNAs to be closely associated with AML prognosis, suggesting the potential application of serum tsRNAs as biomarkers to assist in AML diagnosis. Conclusions: We comprehensively characterized the expression pattern of circulating sncRNAs in blood and bone marrow and their alteration signature between healthy controls and AML patients. This study enriches research of sncRNAs in the regulation of AML, and provides insights into the role of sncRNAs in AML.

KDM4 Demethylases: Structure, Function, and Inhibitors

KDM4 histone demethylases mainly catalyze the removal of methyl marks from H3K9 and H3K36 to epigenetically regulate chromatin structure and gene expression. KDM4 expression is strictly regulated to ensure proper function in a myriad of biological processes, including transcription, cellular proliferation and differentiation, DNA damage repair, immune response, and stem cell self-renewal. Aberrant expression of KDM4 demethylase has been documented in many types of blood and solid tumors, and thus, KDM4s represent promising therapeutic targets. In this chapter, we summarize the current knowledge of the structures and regulatory mechanisms of KDM4 proteins and our understanding of their alterations in human pathological processes with a focus on development and cancer. We also review the reported KDM4 inhibitors and discuss their potential as therapeutic agents.

Targeted Epigenetic Interventions in Cancer with an Emphasis on Pediatric Malignancies

Over the past two decades, novel hallmarks of cancer have been described, including the altered epigenetic landscape of malignant diseases. In addition to the methylation and hyd-roxymethylation of DNA, numerous novel forms of histone modifications and nucleosome remodeling have been discovered, giving rise to a wide variety of targeted therapeutic interventions. DNA hypomethylating drugs, histone deacetylase inhibitors and agents targeting histone methylation machinery are of distinguished clinical significance. The major focus of this review is placed on targeted epigenetic interventions in the most common pediatric malignancies, including acute leukemias, brain and kidney tumors, neuroblastoma and soft tissue sarcomas. Upcoming novel challenges include specificity and potential undesirable side effects. Different epigenetic patterns of pediatric and adult cancers should be noted. Biological significance of epigenetic alterations highly depends on the tissue microenvironment and widespread interactions. An individualized treatment approach requires detailed genetic, epigenetic and metabolomic evaluation of cancer. Advances in molecular technologies and clinical translation may contribute to the development of novel pediatric anticancer treatment strategies, aiming for improved survival and better patient quality of life.