The regulatory role of nickel on H3K27 demethylase JMJD3 in kidney cancer cells

The role of histone methylation in renal cell cancer: an update

Renal cell carcinoma accounts for 2-3% of all cancers. It is difficult to diagnose early. Recently, genome-wide studies have identified that histone methylation was one of the functional classes that is most frequently dysregulated in renal cell cancer. Mutation or mis-regulation of histone methylation, methyltransferases, demethylases are associated with gene expression and tumor progression in renal cell cancer. Herein, we summarize histone methylations, demethylases and their alterations and mechanisms in renal cell cancer.

Epigenetic Regulation in Chromium-, Nickel- and Cadmium-Induced Carcinogenesis

Environmental and occupational exposure to heavy metals, such as hexavalent chromium, nickel, and cadmium, are major health concerns worldwide. Some heavy metals are well-documented human carcinogens. Multiple mechanisms, including DNA damage, dysregulated gene expression, and aberrant cancer-related signaling, have been shown to contribute to metal-induced carcinogenesis. However, the molecular mechanisms accounting for heavy metal-induced carcinogenesis and angiogenesis are still not fully understood. In recent years, an increasing number of studies have indicated that in addition to genotoxicity and genetic mutations, epigenetic mechanisms play critical roles in metal-induced cancers. Epigenetics refers to the reversible modification of genomes without changing DNA sequences; epigenetic modifications generally involve DNA methylation, histone modification, chromatin remodeling, and non-coding RNAs. Epigenetic regulation is essential for maintaining normal gene expression patterns; the disruption of epigenetic modifications may lead to altered cellular function and even malignant transformation. Therefore, aberrant epigenetic modifications are widely involved in metal-induced cancer formation, development, and angiogenesis. Notably, the role of epigenetic mechanisms in heavy metal-induced carcinogenesis and angiogenesis remains largely unknown, and further studies are urgently required. In this review, we highlight the current advances in understanding the roles of epigenetic mechanisms in heavy metal-induced carcinogenesis, cancer progression, and angiogenesis.

Epithelial-mesenchymal transition: Insights into nickel-induced lung diseases

Nickel compounds are environmental toxicants, prevalent in the atmosphere due to their widespread use in several industrial processes, extensive consumption of nickel containing products, as well as burning of fossil fuels. Exposure to nickel is associated with a multitude of chronic inflammatory lung diseases including asthma, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. In addition, nickel exposure is implicated in the development of nasal and lung cancers. Interestingly, a common pathogenic mechanism underlying the development of diseases associated with nickel exposure is epithelial-mesenchymal transition (EMT). EMT is a process by which the epithelial cells lose their junctions and polarity and acquire mesenchymal traits, including increased ability to migrate and invade. EMT is a normal and essential physiological process involved in differentiation, development and wound healing. However, EMT also contributes to a number of pathological conditions, including fibrosis, cancer and metastasis. Growing evidence suggest that EMT induction could be an important outcome of nickel exposure. In this review, we discuss the role of EMT in nickel-induced lung diseases and the mechanisms associated with EMT induction by nickel exposure.

A review on epigenetic effects of environmental factors causing and inhibiting cancer

Epigenetic modifications refer to reversible changes in gene expression. Epigenetic changes include DNA methylation, histone modification, and non-coding RNAs that are collectively called epigenome. Various epigenetic effects account for the main impacts of environment and lifestyle on multifactorial diseases such as cancers. The environment's impacts on cancers act as double-edged swords. While some of them are involved in cancer development, some others contribute to preventing it. In this review article, the keywords 'cancer', 'epigenetic', 'lifestyle', 'carcinogen', ' cancer inhibitors" and related words were searched to finding a link between environmental factors and epigenetic mechanisms influencing cancer in ISI, PUBMED, SCOPUS, and Google Scholar databases. Based on the literature environmental factors that are effective in cancer development or cancer prevention in this review will be divided into physical, chemical, biological, and lifestyle types. Different types of epigenetic mechanisms known for each of these agents will be addressed in this review. Unregulated changes in epigenome play roles in tumorigenicity and cancer development. The action mechanism and genes targeted which are related to the signaling pathway for epigenetic alterations determine whether environmental agents are carcinogenic or prevent cancer. Having knowledge about the effective factors and related mechanisms such as epigenetic on cancer can help to prevent and better cancers treatment.

JMJD3 inhibition protects against isoproterenol-induced cardiac hypertrophy by suppressing β-MHC expression

Jumonji domain-containing protein D3 (JMJD3), a histone 3 lysine 27 (H3K27) demethylase, has been extensively studied for their participation in development, cellular physiology and a variety of diseases. However, its potential roles in cardiovascular system remain unknown. In this study, we found that JMJD3 played a pivotal role in the process of cardiac hypertrophy. JMJD3 expression was elevated by isoproterenol (ISO) stimuli both in vitro and in vivo. Overexpression of wild-type JMJD3, but not the demethylase-defective mutant, promoted cardiomyocyte hypertrophy, as implied by increased cardiomyocyte surface area and the expression of hypertrophy marker genes. In contrary, JMJD3 silencing or its inhibitor GSK-J4 suppressed ISO-induced cardiac hypertrophy. Mechanistically, JMJD3 was recruited to demethylate H3K27me3 at the promoter of β-MHC to promote its expression and cardiac hypertrophy. Thus, our results reveal that JMJD3 may be a key epigenetic regulator of β-MHC expression in cardiomyocytes and a potential therapeutic target for cardiac hypertrophy.

The Emerging Role of Histone Demethylases in Renal Cell Carcinoma

Renal cell carcinoma (RCC), the most common kidney cancer, is responsible for more than 100,000 deaths per year worldwide. The molecular mechanism of RCC is poorly understood. Many studies have indicated that epigenetic changes such as DNA methylation, noncoding RNAs, and histone modifications are central to the pathogenesis of cancer. Histone demethylases (KDMs) play a central role in histone modifications. There is emerging evidence that KDMs such as KDM3A, KDM5C, KDM6A, and KDM6B play important roles in RCC. The available literature suggests that KDMs could promote RCC development and progression via hypoxia-mediated angiogenesis pathways. Small-molecule inhibitors of KDMs are being developed and used in preclinical studies; however, their clinical relevance is yet to be established. In this mini review, we summarize our current knowledge on the putative role of histone demethylases in RCC.

Aberrant JMJD3 Expression Upregulates Slug to Promote Migration, Invasion, and Stem Cell-Like Behaviors in Hepatocellular Carcinoma

The Jumonji domain-containing chromatin remodeling factor JMJD3 has important roles in development and cancer. Here, we report a pivotal role for JMJD3 in sustaining the phenotype of aggressive hepatocellular carcinomas. Expression levels of JMJD3 in clinical specimens of hepatocellular carcinoma correlated inversely with patient survival. In hepatocellular carcinoma cells, we found that enforcing its overexpression induced epithelial-mesenchymal transition (EMT), invasive migration, stem cell-like traits, and metastatic properties. Conversely, silencing JMJD3 in hepatocellular carcinoma cells overexpressing it inhibited these aggressive phenotypes. Mechanistically, JMJD3 modulated H3K27me3 in the SLUG gene promoter, a histone mark associated with active SLUG transcription. SLUG silencing blocked JMJD3-induced EMT, stemness, and metastasis. Furthermore, SLUG expression in hepatocellular carcinoma clinical specimens correlated positively with JMJD3 expression. Our results establish JMJD3 as a critical driver of hepatocellular carcinoma stem cell-like and metastatic behaviors, with implications for prognosis and treatment. Cancer Res; 76(22); 6520-32. ©2016 AACR.

Histone demethylase JMJD3 at the intersection of cellular senescence and cancer

Cellular senescence is defined by an irreversible growth arrest and is an important biological mechanism for suppression of tumor formation. Although deletion/mutation to DNA sequences is one mechanism by which cancer cells can escape senescence, little is known about the epigenetic factors contributing to this process. Histone modifications and chromatin remodeling related to the function of a histone demethylase, jumonji domain-containing protein 3 (JMJD3; also known as KDM6B), play an important role in development, tissue regeneration, stem cells, inflammation, and cellular senescence and aging. The role of JMJD3 in cancer is poorly understood and its function may be at the intersection of many pathways promoted in a dysfunctional manner such as activation of the senescence-associated secretory phenotype (SASP) observed in aging.

JMJD3 as an epigenetic regulator in development and disease

Gene expression is epigenetically regulated through DNA methylation and covalent chromatin modifications, such as acetylation, phosphorylation, ubiquitination, sumoylation, and methylation of histones. Histone methylation state is dynamically regulated by different groups of histone methyltransferases and demethylases. The trimethylation of histone 3 (H3K4) at lysine 4 is usually associated with the activation of gene expression, whereas trimethylation of histone 3 at lysine 27 (H3K27) is associated with the repression of gene expression. The polycomb repressive complex contains the H3K27 methyltransferase Ezh2 and controls dimethylation and trimethylation of H3K27 (H3K27me2/3). The Jumonji domain containing-3 (Jmjd3, KDM6B) and ubiquitously transcribed X-chromosome tetratricopeptide repeat protein (UTX, KDM6A) have been identified as H3K27 demethylases that catalyze the demethylation of H3K27me2/3. The role and mechanisms of both JMJD3 and UTX have been extensively studied for their involvement in development, cell plasticity, immune system, neurodegenerative disease, and cancer. In this review, we will focus on recent progresses made on understanding JMJD3 in the regulation of gene expression in development and diseases. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.