JMJD3 suppresses stem cell-like characteristics in breast cancer cells by downregulation of Oct4 independently of its demethylase activity

Bidirectional regulation of postmitotic H3K27me3 distributions underlie cerebellar granule neuron maturation dynamics

The functional maturation of neurons is a prolonged process that extends past the mitotic exit and is mediated by the chromatin-dependent orchestration of gene transcription programs. We find that expression of this maturation gene program in mouse cerebellar granule neurons (CGNs) requires dynamic changes in the genomic distribution of histone H3 lysine 27 trimethylation (H3K27me3), demonstrating a function for this chromatin modification beyond its role in cell fate specification. The developmental loss of H3K27me3 at promoters of genes activated as CGNs mature is facilitated by the lysine demethylase and ASD-risk gene, Kdm6b. Interestingly, inhibition of the H3K27 methyltransferase EZH2 in newborn CGNs not only blocks the repression of progenitor genes but also impairs the induction of mature CGN genes, showing the importance of bidirectional H3K27me3 regulation across the genome. These data demonstrate that H3K27me3 turnover in developing postmitotic neurons regulates the temporal coordination of gene expression programs that underlie functional neuronal maturation.

KDM6B regulates M2 polarization of macrophages by modulating the stability of nuclear β-catenin

Accumulating evidences suggest that the epigenetic regulation plays a pivotal role in establishing phenotype and function of tumor associated macrophages (TAMs). KDM6B is an epigenetic enzyme responsible for the H3K27me3 and reported to influence macrophage polarization. However, the underlying mechanism remains to be determined. Here, we demonstrated that inhibition of KDM6B in TAMs increased M2 polarization induced by coculture of breast cancer cells. Furthermore, we identified that KDM6B downregulation activated β-catenin/c-Myc signaling, and thus promoted the M2-like phenotype. KDM6B accelerated the intranuclear ubiquitination degradation of β-catenin, which depended on its demethylase activity. Therapeutically, our data showed that activated vitamin D analog paricalcitol upregulated the expression of KDM6B and decreased the M2 polarization, consequently protected against tumor progress in the xenograft mouse model of breast cancer. Taken together, our data reveal that epigenetic regulator KDM6B prevents M2 polarization via promoting the intranuclear degradation of β-catenin. Active vitamin D analog induces KDM6B and suppresses tumor progress, suggesting a novel therapeutic potential of epigenetic modulation for the tumor treatment.

Diallyl Trisulfide Suppresses the Renal Cancer Stem-like Cell Properties via Nanog

Cancer stem-like cells (CSCs), which play an important role in tumor initiation and progression, have been identified in many cancers. Diallyl trisulfide (DATS) is an organosulfur compound extracted from garlic with anticancer activities. Nanog is a transcription factor responsible for maintaining the stemness of CSCs, but its role in the DATS-induced attenuation of renal CSC properties is unknown. In this study, renal CSCs were enriched from human renal cancer cell lines 786-O and ACHN cultured in a serum-free medium (SFM). The properties of CSCs were analyzed by evaluating the ability of the cells in sphere formation and measuring the expression of stem cell markers. We found that downregulation of Nanog inhibited renal CSC properties. DATS suppressed renal CSC activities by reducing tumorsphere formation, decreasing stem cell markers including Nanog, CD44, ALDH1A1, and Oct4, inhibiting cell proliferation and promoting apoptosis. We further revealed that overexpression of Nanog reversed the suppressive effects of DATS on renal CSCs. Taken together, our results demonstrated that DATS inhibited renal CSCs by suppressing Nanog. These novel findings suggested that, through Nanog targeting, DATS can potentially be used as an anti-tumor agent for renal cancer.

Advances in Biomarkers and Endogenous Regulation of Breast Cancer Stem Cells

Breast cancer is one of the most common cancers. Even if breast cancer patients initially respond to treatment, developed resistance can lead to a poor prognosis. Cancer stem cells (CSCs) are a group of undifferentiated cells with self-renewal and multipotent differentiation characteristics. Existing evidence has shown that CSCs are one of the determinants that contribute to the heterogeneity of primary tumors. The emergence of CSCs causes tumor recurrence, metastasis, and therapeutic resistance. Previous studies indicated that different stemness-associated surface markers can identify other breast cancer stem cell (BCSC) subpopulations. Deciphering the critical signaling networks that are involved in the induction and maintenance of stemness is essential to develop novel BCSC-targeting strategies. In this review, we reviewed the biomarkers of BCSCs, critical regulators of BCSCs, and the signaling networks that regulate the stemness of BCSCs.

Histone modification and histone modification-targeted anti-cancer drugs in breast cancer: Fundamentals and beyond

Dysregulated epigenetic enzymes and resultant abnormal epigenetic modifications (EMs) have been suggested to be closely related to tumor occurrence and progression. Histone modifications (HMs) can assist in maintaining genome stability, DNA repair, transcription, and chromatin modulation within breast cancer (BC) cells. In addition, HMs are reversible, dynamic processes involving the associations of different enzymes with molecular compounds. Abnormal HMs (e.g. histone methylation and histone acetylation) have been identified to be tightly related to BC occurrence and development, even though their underlying mechanisms remain largely unclear. EMs are reversible, and as a result, epigenetic enzymes have aroused wide attention as anti-tumor therapeutic targets. At present, treatments to restore aberrant EMs within BC cells have entered preclinical or clinical trials. In addition, no existing studies have comprehensively analyzed aberrant HMs within BC cells; in addition, HM-targeting BC treatments remain to be further investigated. Histone and non-histone protein methylation is becoming an attractive anti-tumor epigenetic therapeutic target; such methylation-related enzyme inhibitors are under development at present. Consequently, the present work focuses on summarizing relevant studies on HMs related to BC and the possible mechanisms associated with abnormal HMs. Additionally, we also aim to analyze existing therapeutic agents together with those drugs approved and tested through pre-clinical and clinical trials, to assess their roles in HMs. Moreover, epi-drugs that target HMT inhibitors and HDAC inhibitors should be tested in preclinical and clinical studies for the treatment of BC. Epi-drugs that target histone methylation (HMT inhibitors) and histone acetylation (HDAC inhibitors) have now entered clinical trials or are approved by the US Food and Drug Administration (FDA). Therefore, the review covers the difficulties in applying HM-targeting treatments in clinics and proposes feasible approaches for overcoming such difficulties and promoting their use in treating BC cases.

Targeting histone methylation to reprogram the transcriptional state that drives survival of drug-tolerant myeloid leukemia persisters

Although chemotherapy induces complete remission in the majority of acute myeloid leukemia (AML) patients, many face a relapse. This relapse is caused by survival of chemotherapy-resistant leukemia (stem) cells (measurable residual disease; MRD). Here, we demonstrate that the anthracycline doxorubicin epigenetically reprograms leukemia cells by inducing histone 3 lysine 27 (H3K27) and H3K4 tri-methylation. Within a doxorubicin-sensitive leukemia cell population, we identified a subpopulation of reversible anthracycline-tolerant cells (ATCs) with leukemic stem cell (LSC) features lacking doxorubicin-induced H3K27me3 or H3K4me3 upregulation. These ATCs have a distinct transcriptional landscape than the leukemia bulk and could be eradicated by KDM6 inhibition. In primary AML, reprogramming the transcriptional state by targeting KDM6 reduced MRD load and survival of LSCs residing within MRD, and enhanced chemotherapy response in vivo. Our results reveal plasticity of anthracycline resistance in AML cells and highlight the potential of transcriptional reprogramming by epigenetic-based therapeutics to target chemotherapy-resistant AML cells.

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Reversible anthracycline-tolerant leukemia cells (ATCs) have low H3K27me3 or H3K4me3

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ATCs exhibit stem cell features similar to leukemic stem cells

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Reprogramming the transcriptional state by inhibition of KDM6 depletes ATCs

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Inhibiting KDM6 adds to doxorubicin treatment and eradicates AML MRD (stem) cells

Emerging roles of JMJD3 in cancer

Histone lysine methylation plays a key role in gene activation and repression. The trimethylation of histone H3 on lysine-27 (H3K27me3) is a critical epigenetic event that is controlled by Jumonji domain-containing protein-3 (JMJD3). JMJD3 is a histone demethylase that specifically removes methyl groups. Previous studies have suggested that JMJD3 has a dual role in cancer cells. JMJD3 stimulates the expression of proliferative-related genes and increases tumor cell growth, propagation, and migration in various cancers, including neural, prostate, ovary, skin, esophagus, leukemia, hepatic, head and neck, renal, lymphoma, and lung. In contrast, JMJD3 can suppress the propagation of tumor cells, and enhance their apoptosis in colorectal, breast, and pancreatic cancers. In this review, we summarized the recent advances of JMJD3 function in cancer cells.

KDM6 Demethylases and Their Roles in Human Cancers

Cancer therapy is moving beyond traditional chemotherapy to include epigenetic approaches. KDM6 demethylases are dynamic regulation of gene expression by histone demethylation in response to diverse stimuli, and thus their dysregulation has been observed in various cancers. In this review, we first briefly introduce structural features of KDM6 subfamily, and then discuss the regulation of KDM6, which involves the coordinated control between cellular metabolism (intrinsic regulators) and tumor microenvironment (extrinsic stimuli). We further describe the aberrant functions of KDM6 in human cancers, acting as either a tumor suppressor or an oncoprotein in a context-dependent manner. Finally, we propose potential therapy of KDM6 enzymes based on their structural features, epigenetics, and immunomodulatory mechanisms, providing novel insights for prevention and treatment of cancers.

Control of Breast Cancer Pathogenesis by Histone Methylation and the Hairless Histone Demethylase

Breast cancer is a highly heterogeneous disease, encompassing many subtypes that have distinct origins, behaviors, and prognoses. Although traditionally seen as a genetic disease, breast cancer is now also known to involve epigenetic abnormalities. Epigenetic regulators, such as DNA methyltransferases and histone-modifying enzymes, play essential roles in gene regulation and cancer development. Dysregulation of epigenetic regulator activity has been causally linked with breast cancer pathogenesis. Hairless (HR) encodes a 130-kDa transcription factor that is essential for development and tissue homeostasis. Its role in transcription regulation is partly mediated by its interaction with multiple nuclear receptors, including thyroid hormone receptor, retinoic acid receptor-related orphan receptors, and vitamin D receptor. HR has been studied primarily in epidermal development and homeostasis. Hr-mutant mice are highly susceptible to ultraviolet- or carcinogen-induced skin tumors. Besides its putative tumor suppressor function in skin, loss of HR function has also been implicated in increased leukemia susceptibility and promotes the growth of melanoma and brain cancer cells. HR has also been demonstrated to function as a histone H3 lysine 9 demethylase. Recent genomics studies have identified HR mutations in a variety of human cancers, including breast cancer. The anticancer function and mechanism of action by HR in mammary tissue remains to be investigated. Here, we review the emerging role of HR, its histone demethylase activity and histone methylation in breast cancer development, and potential for epigenetic therapy.

JMJD3: a critical epigenetic regulator in stem cell fate

The Jumonji domain-containing protein-3 (JMJD3) is a histone demethylase that regulates the trimethylation of histone H3 on lysine 27 (H3K27me3). H3K27me3 is an important epigenetic event associated with transcriptional silencing. JMJD3 has been studied extensively in immune diseases, cancer, and tumor development. There is a comprehensive epigenetic transformation during the transition of embryonic stem cells (ESCs) into specialized cells or the reprogramming of somatic cells to induced pluripotent stem cells (iPSCs). Recent studies have illustrated that JMJD3 plays a major role in cell fate determination of pluripotent and multipotent stem cells (MSCs). JMJD3 has been found to enhance self-renewal ability and reduce the differentiation capacity of ESCs and MSCs. In this review, we will focus on the recent advances of JMJD3 function in stem cell fate.

Histone demethylase KDM6B inhibits breast cancer metastasis by regulating Wnt/β-catenin signaling

Tumor metastasis remains a major challenge for patients with breast cancer. Aberrant epigenetic factor lysine‐specific demethylase 6B (KDM6B) has been associated with tumor progression. Here, we show that KDM6B is significantly down‐regulated in human breast cancer tissues, and its low expression is associated with poor prognosis of patients with breast cancer. Furthermore, overexpression of KDM6B remarkably inhibited cell proliferation, invasion, migration and epithelial–mesenchymal transition markers of breast cancer cells in vitro and tumor growth and lung metastasis in vivo. Notably, the expression of KDM6B in breast cancer tissues was negatively correlated with that of β‐catenin, and overexpression of KDM6B decreased the expression of β‐catenin and its accumulation in the nucleus of breast cancer cells. Overall, our findings provide novel insights into suppression of metastasis of breast cancer cells by KDM6B via β‐catenin and suggest involvement of the KDM6B‐Wnt/β‐catenin axis in breast cancer progression.

Unlocking the Recovery Potential: JMJD3 Inhibition-Mediated SAPK/JNK Signaling Inactivation Supports Endogenous Oligodendrocyte-Lineage Commitment Post Mammalian Spinal Cord Injury

Spinal cord injury (SCI) induced catastrophic neurological disability is often incurable at present. The injury triggered immediately oligodendrocytes loss and overwhelming demyelination are regarded as an insurmountable barrier to SCI recovery. To date, effective strategy to promote the endogenous oligodendrocytes replacement post SCI remains elusive. Epigenetic modifications are emerging as critical molecular switches of gene expression in CNS. However, the epigenetic mechanisms underlying oligodendrogenesis post SCI yet to be discovered. In this study, we report that H3K27me3 demethylase JMJD3 exists as a pivotal epigenetic regulator which manipulates the endogenous oligodendrogenesis post SCI. We found that JMJD3 inhibition promotes the oligodendrocyte linage commitment of neural stem/progenitor cells (NPCs) in vitro and in vivo. Moreover, we demonstrated that JMJD3 inhibition mediated SAPK/JNK signaling inactivation is functionally necessary for endogenous oligodendrocyte-lineage commitment post SCI. Our results also suggested that JMJD3 is downstream of SAPK/JNK pathway, and capable of translates SCI induced SAPK/JNK signaling into epigenetic codes readable by spinal cord endogenous NPCs. Taken together, our findings provide novel evidence of JMJD3 mediated oligodendrocyte-lineage commitment orchestration post SCI, which would be a potential epigenetic approach to induce the mature mammalian endogenous recovery.

KDM6B (JMJD3) and its dual role in cancer

Epigenetic modifications play a fundamental role in the regulation of gene expression and cell fate. During the development of cancer, epigenetic modifications appear that favor cell proliferation and migration, but at the same time prevent differentiation and apoptosis, among other processes. KDM6B is a histone demethylase that specifically removes methyl groups from H3K27me3, thus allowing re-expression of its target genes. It is currently known that KDM6B can act as both a tumor suppressor and an oncogene depending on the cellular context. Therefore, in this work we summarize the current knowledge of the role that KDM6B plays in different oncological contexts, and we try to orient it towards its clinical application.

The Functions of the Demethylase JMJD3 in Cancer

Cancer is a major cause of death worldwide. Epigenetic changes in response to external (diet, sports activities, etc.) and internal events are increasingly implicated in tumor initiation and progression. In this review, we focused on post-translational changes in histones and, more particularly, the tri methylation of lysine from histone 3 (H3K27me3) mark, a repressive epigenetic mark often under- or overexpressed in a wide range of cancers. Two actors regulate H3K27 methylation: Jumonji Domain-Containing Protein 3 demethylase (JMJD3) and Enhancer of zeste homolog 2 (EZH2) methyltransferase. A number of studies have highlighted the deregulation of these actors, which is why this scientific review will focus on the role of JMJD3 and, consequently, H3K27me3 in cancer development. Data on JMJD3’s involvement in cancer are classified by cancer type: nervous system, prostate, blood, colorectal, breast, lung, liver, ovarian, and gastric cancers.

Tamoxifen induces stem-like phenotypes and multidrug resistance by altering epigenetic regulators in ERα+ breast cancer cells

Background

To understand the mechanism underlying tamoxifen-induced multidrug resistance (MDR) and stem-like phenotypes in breast cancer cells, we treated the MCF-7 cells with 4-hydroxy-tamoxifen (TAM) for 6 months continuously and established MCF-7 tamoxifen resistance (TR) phenotypes.

Methods

In the present study, the following methods were used: cell viability assay, colony formation, cell cycle analysis, ALDEFLUOR assay, mammosphere formation assay, chromatin immunoprecipitation (ChIP) assay, PCR array, western blot analysis and quantitative reverse transcription polymerase chain reaction (QRT-PCR).

Results

The expression of ERα was significantly higher in MCF7-TR cells when compared with parental MCF-7 cells. MCF7-TR cells exposed to TAM showed a significant increase in the proliferation and rate of colony formation. The number of cancer stem cells was higher in MCF7-TR cells as observed by the increase in the number of ALDH+ cells. Furthermore, the number of mammospheres formed from the FACS-sorted ALDH+ cells was higher in MCF7-TR cells. Using PCR array analysis, we were able to identify that the long-term exposure of TAM leads to alterations in the epigenetic and MDR stem cell marker genes. Furthermore, western blot analysis demonstrated elevated levels of Notch-1 expression in MCF-TR cells compared with MCF-7 cells. Chromatin immunoprecipitation (ChIP) assay revealed that Notch-1 enhanced the cyclin D1 expression significantly in these cells. In addition, we observed that MCF7-TR cells were resistant to doxorubicin but not the MCF-7 cells.

Conclusions

In the present study, we conclude that the treatment with tamoxifen induces multiple epigenetic alterations that lead to the development of MDR and stem-like phenotypes in breast cancers. Therefore, our study provides better insights to develop novel treatment regime to control the progression of breast cancer.

The Role and Specific Mechanism of OCT4 in Cancer Stem Cells: A Review

Recently, evidences show that cancer stem cells (CSCs) are a type of cancer cell group with self-renewal and play a huge role in tumor recurrence, metastasis, and drug resistance. Finding new treatment directions and targets for cancer prognosis and reducing mortality has become a top priority. OCT4, as a transcription factor, participates in maintaining the stem characteristics of CSCs, but the mechanism of OCT4 is often overlooked. In this review, we try to illustrate the mechanism by which OCT4 plays a role in CSCs from the perspective of genetic modification of OCT4, non-coding RNA, complexes and signaling pathways associated with OCT4. Our ultimate goal is to provide new targets for cancer treatment to prolong the survival of cancer patients.

Yin Yang 1 is required for PHD finger protein 20-mediated myogenic differentiation in vitro and in vivo

The development of skeletal muscle requires progression of a highly ordered cascade of events comprising myogenic lineage commitment, myoblast proliferation, and terminal differentiation. The process of myogenesis is controlled by several myogenic transcription factors that act as terminal effectors of signaling cascades and produce appropriate developmental stage-specific transcripts. PHD finger protein 20 (PHF20) is a multidomain protein and subunit of a lysine acetyltransferase complex that acetylates histone H4 and p53, but its function is unclear. Notably, it has been reported that PHF20 knockout mice die shortly after birth and display a wide variety of phenotypes within the skeletal and hematopoietic systems. Therefore, the putative role of PHF20 in myogenic differentiation was further investigated. In the present study, we found that protein and mRNA expression levels of PHF20 were decreased during myogenic differentiation in C₂C₁₂ cells. At the same time, Yin Yang 1 (YY1) was also decreased during myogenic differentiation. PHF20 overexpression increased YY1 expression during myogenic differentiation, together with a delay in MyoD expression. PHF20 expression enhanced the transcriptional activity of YY1 while shRNA-mediated depletion of PHF20 resulted in the reduction of YY1 promoter activity in C₂C₁₂ cells. In addition, PHF20 directly bounds to the YY1 promoter in C₂C₁₂ cells. In a similar manner, YY1 expression was elevated while myosin heavy chain expression was decreased in PHF20 transgenic (TG) mice. Histological analysis revealed abnormalities in the shape and length of muscles in PHF20-TG mice. Furthermore, PHF20-TG muscles slowly regenerated after cardiotoxin injection, indicating that PHF20 affected muscle differentiation and regeneration after injury in vivo. Taken together, these results suggested that PHF20 plays an important role in myogenic differentiation by regulating YY1.

Cancer Stem Cells: Powerful Targets to Improve Current Anticancer Therapeutics

A frequent observation in several malignancies is the development of resistance to therapy that results in frequent tumor relapse and metastasis. Much of the tumor resistance phenotype comes from its heterogeneity that halts the ability of therapeutic agents to eliminate all cancer cells effectively. Tumor heterogeneity is, in part, controlled by cancer stem cells (CSC). CSC may be considered the reservoir of cancer cells as they exhibit properties of self-renewal and plasticity and the capability of reestablishing a heterogeneous tumor cell population. The endowed resistance mechanisms of CSC are mainly attributed to several factors including cellular quiescence, accumulation of ABC transporters, disruption of apoptosis, epigenetic reprogramming, and metabolism. There is a current need to develop new therapeutic drugs capable of targeting CSC to overcome tumor resistance. Emerging in vitro and in vivo studies strongly support the potential benefits of combination therapies capable of targeting cancer stem cell-targeting agents. Clinical trials are still underway to address the pharmacokinetics, safety, and efficacy of combination treatment. This review will address the main characteristics, therapeutic implications, and perspectives of targeting CSC to improve current anticancer therapeutics.

JMJD3 promotes the epithelial-mesenchymal transition and migration of glioma cells via the CXCL12/CXCR4 axis

Histone H3K27 demethylase Jumonji domain-containing protein 3 (JMJD3) is involved in somatic cell differentiation and tumor progression; however, the underlying mechanisms of JMJD3 in cancer progression are yet to be fully explored. To improve understanding regarding the function of JMJD3 in brain tumor cells, the present study investigated the effects of JMJD3 on the epithelial-mesenchymal transition (EMT) and migration in glioma cells, and the underlying mechanisms involving the C-X-C motif chemokine ligand 12 (CXCL12)/C-X-C motif chemokine receptor 4 (CXCR4) axis. Immunohistochemical staining of a tissue microarray of glioma samples confirmed that JMJD3 overexpression could stratify highly metastatic glioma. The overexpression of JMJD3 induced a spindle-shaped morphology, promoted N-cadherin expression, inhibited E-cadherin expression and enhanced the migration ability of U-251MG and U-87MG American Type Culture Collection cells. The expression of E-cadherin and N-cadherin were assessed by western blotting and reverse transcription-quantitative polymerase chain reaction, and cell migration was evaluated using a Transwell migration assay and wound-healing. The overexpression of JMJD3 upregulated CXCL12 expression in a demethylase activity-dependent manner as ChIP assays revealed a decrease in H3K27 trimethylation at the CXCL12 promoter following overexpression of JMJD3 in U-87MG ATCC cells. Accordingly, CXCL12 overexpression was sufficient to rescue the suppressive effects of JMJD3 inhibition on the EMT and migration in glioma cells. In addition, CXCR4 expression was not regulated by JMJD3, but the interruption of CXCR4 caused by the CXCR4 inhibitor AMD3100 abolished the promotional effect of JMJD3 on EMT and migration in glioma cells. Collectively, these results suggested that JMJD3 promoted EMT and migration in glioma cells via the CXCL12/CXCR4 axis. The present study described a novel epigenetic mechanism regulating tumor cell EMT and migration, and provided a novel direction for glioma diagnosis and treatment.

The role and prospect of JMJD3 in stem cells and cancer

Currently, stem cells are reported to be involved in tumor formation, drug resistance and recurrence. Inhibiting the proliferation of tumor cells, promoting their senescence and apoptosis has been the most important anti-tumor therapy. Epigenetics is involved in the regulation of gene expression and is closely related to cancer and stem cells. It mainly includes DNA methylation, histone modification, and chromatin remodeling. Histone methylation and demethylation play an important role in histone modification. Histone 3 lysine 27 trimethylation (H3K27me3) induces transcriptional inhibition and plays an important role in gene expression. Jumonji domain-containing protein-3 (JMJD3), one of the demethyases of histone H3K27me3, has been reported to be associated with the prognosis of many cancers and stem cells differentiation. Inhibition of JMJD3 can reduce proliferation and promote apoptosis in tumor cells, as well as suppress differentiation in stem cells. GSK-J4 is an inhibitor of demethylase JMJD3 and UTX, which has been shown to possess anti-cancer and inhibition of embryonic stem cells differentiation effects. In this review, we examine how JMJD3 regulates cellular fates of stem cells and cancer cells and references were identified through searches of PubMed, Medline, Web of Science.

Lineage specific transcription factors and epigenetic regulators mediate TGFβ-dependent enhancer activation

During neurogenesis, dynamic developmental cues, transcription factors and histone modifying enzymes regulate the gene expression programs by modulating the activity of neural-specific enhancers. How transient developmental signals coordinate transcription factor recruitment to enhancers and to which extent chromatin modifiers contribute to enhancer activity is starting to be uncovered. Here, we take advantage of neural stem cells as a model to unravel the mechanisms underlying neural enhancer activation in response to the TGFβ signaling. Genome-wide experiments demonstrate that the proneural factor ASCL1 assists SMAD3 in the binding to a subset of enhancers. Once located at the enhancers, SMAD3 recruits the histone demethylase JMJD3 and the remodeling factor CHD8, creating the appropriate chromatin landscape to allow enhancer transcription and posterior gene activation. Finally, to analyze the phenotypical traits owed to cis-regulatory regions, we use CRISPR–Cas9 technology to demonstrate that the TGFβ-responsive Neurog2 enhancer is essential for proper neuronal polarization.

The Unexpected Noncatalytic Roles of Histone Modifiers in Development and Disease

Epigenetic regulation is critical for the precise control of cellular fate and developmental programs. Disruption of epigenetic information is increasingly appreciated as a potential driving mechanism in both developmental disorders as well as ubiquitous diseases such as cancer. Consistent with this, mutations in histone modifying enzymes are amongst the most frequent events in all of human cancer. While early studies have focused on the canonical enzymatic functions involved in catalyzing modifications to histones, more recent studies have uncovered a new layer of critical nonenzymatic roles in transcriptional regulation for these proteins. Here, we provide an overview of these surprising, yet exciting, noncanonical, noncatalytic roles, and highlight how these revelations may have important implications for understanding disease and the future of epigenome-targeting therapies.

Hepatocyte PRMT1 protects from alcohol induced liver injury by modulating oxidative stress responses

Protein Arginine methyltransferase 1 (PRMT1) is the main enzyme of cellular arginine methylation. Previously we found that PRMT1 activity in the liver is altered after alcohol exposure resulting in epigenetic changes. To determine the impact of these PRMT1 changes on the liver's response to alcohol, we induced a hepatocyte specific PRMT1 knockout using AAV mediated Cre delivery in mice fed either alcohol or control Lieber-DeCarli liquid diet. We found that in alcohol fed mice, PRMT1 prevents oxidative stress and promotes hepatocyte survival. PRMT1 knockout in alcohol fed mice resulted in a dramatic increase in hepatocyte death, inflammation and fibrosis. Additionally, we found that alcohol promotes PRMT1 dephosphorylation at S297. Phosphorylation at this site is necessary for PRMT1-dependent protein arginine methylation. PRMT1 S297A, a dephosphorylation mimic of PRMT1 had reduced ability to promote gene expression of pro-inflammatory cytokines, pro-apoptotic genes BIM and TRAIL and expression of a suppressor of hepatocyte proliferation, Hnf4α. On the other hand, several functions of PRMT1 were phosphorylation-independent, including expression of oxidative stress response genes, Sod1, Sod2 and others. In vitro, both wild type and S297A PRMT1 protected hepatocytes from oxidative stress induced apoptosis, however S297D phosphorylation mimic PRMT1 promoted cell death. Taken together these data suggest that PRMT1 is an essential factor of liver adaptation to alcohol; alcohol-induced dephosphorylation shifts PRMT1 toward a less pro-inflammatory, more pro-proliferative and pro-survival form.

Iron in the Tumor Microenvironment-Connecting the Dots

Iron metabolism and tumor biology are intimately linked. Iron facilitates the production of oxygen radicals, which may either result in iron-induced cell death, ferroptosis, or contribute to mutagenicity and malignant transformation. Once transformed, malignant cells require high amounts of iron for proliferation. In addition, iron has multiple regulatory effects on the immune system, thus affecting tumor surveillance by immune cells. For these reasons, inconsiderate iron supplementation in cancer patients has the potential of worsening disease course and outcome. On the other hand, chronic immune activation in the setting of malignancy alters systemic iron homeostasis and directs iron fluxes into myeloid cells. While this response aims at withdrawing iron from tumor cells, it may impair the effector functions of tumor-associated macrophages and will result in iron-restricted erythropoiesis and the development of anemia, subsequently. This review summarizes our current knowledge of the interconnections of iron homeostasis with cancer biology, discusses current clinical controversies in the treatment of anemia of cancer and focuses on the potential roles of iron in the solid tumor microenvironment, also speculating on yet unknown molecular mechanisms.

Exosomes Regulate the Transformation of Cancer Cells in Cancer Stem Cell Homeostasis

In different biological model systems, exosomes are considered mediators of cell-cell communication between different cell populations. Exosomes, as extracellular vesicles, participate in physiological and pathological processes by transmitting signaling molecules such as proteins, nucleic acids, and lipids. The tumor's microenvironment consists of many types of cells, including cancer stem cells and mesenchymal cells. It is well known that these cells communicate with each other and thereby regulate the progression of the tumor. Recent studies have provided evidence that exosomes mediate the interactions between different types of cells in the tumor microenvironment, providing further insight into how these cells interact through exosome signaling. Cancer stem cells are a small kind of heterogeneous cells that existed in tumor tissues or cancer cell lines. These cells possess a stemness phenotype with a self-renewal ability and multipotential differentiation which was considered the reason for the failure of conventional cancer therapies and tumor recurrence. However, a highly dynamic equilibrium was found between cancer stem cells and cancer cells, and this indicates that cancer stem cells are no more special target and blocking the transformation of cancer stem cells and cancer cells seem to be a more significant therapy strategy. Whether exosomes, as an information transforming carrier between cells, regulated cancer cell transformation in cancer stem cell dynamic equilibrium and targeting exosome signaling attenuated the formation of cancer stem cells and finally cure cancers is worthy of further study.

Application of induced pluripotency in cancer studies

As soon as induced pluripotent stem cells (iPSCs) reprogramming of somatic cells were developed, the discovery attracted the attention of scientists, offering new perspectives for personalized medicine and providing a powerful platform for drug testing. The technology was almost immediately applied to cancer studies. As presented in this review, direct reprogramming of cancer cells with enforced expression of pluripotency factors have several basic purposes, all of which aim to explain the complex nature of cancer development and progression, therapy-resistance and relapse, and ultimately lead to the development of novel anti-cancer therapies. Here, we briefly present recent advances in reprogramming methodologies as well as commonalities between cell reprogramming and carcinogenesis and discuss recent outcomes from the implementation of induced pluripotency into cancer research.