The pharmacological role of histone demethylase JMJD3 inhibitor GSK-J4 on glioma cells

Epigenetic reprogramming in pediatric gliomas: from molecular mechanisms to therapeutic implications

Brain tumors in children and adults differ greatly in patient outcomes and responses to radiotherapy and chemotherapy. Moreover, the prevalence of recurrent mutations in histones and chromatin regulatory proteins in pediatric and young adult gliomas suggests that the chromatin landscape is rewired to support oncogenic programs. These early somatic mutations dysregulate widespread genomic loci by altering the distribution of histone post-translational modifications (PTMs) and, in consequence, causing changes in chromatin accessibility and in the histone code, leading to gene transcriptional changes. We review how distinct chromatin imbalances in glioma subtypes impact on oncogenic features such as cellular fate, proliferation, immune landscape, and radio resistance. Understanding these mechanisms of epigenetic dysregulation carries substantial implications for advancing targeted epigenetic therapies.

The role of trimethylation on histone H3 lysine 27 (H3K27me3) in temozolomide resistance of glioma

Temozolomide (TMZ) is the first-line chemotherapeutic agent for malignant glioma, but its resistance limited the benefits of the treated patients. In this study, the role and significance of trimethylation of histone H3 lysine 27 (H3K27me3) in TMZ resistance were investigated. Data from twenty advanced glioma patients were collected, and their pathological samples were analyzed for H3K27me3 levels. TMZ sensitivity was compared between glioma cells U87 and TMZ-resistant cells U87TR, with H3K27me3 levels determined in both cells. The effects of H3K27me3 demethylases inhibitor GSK-J4, combined with TMZ, were assessed on the proliferation and migration of U87TR cells. The results indicated that a high level of H3K27me3 predicts longer disease free survival (DFS) and overall survival (OS) in glioma patients receiving TMZ treatment. The H3K27me3 level was lower in U87TR cells compared to U87 cells. GSK-J4 increased the H3K27me3 level in U87TR cells and decreased their resistance to TMZ. In summary, this study identified a novel marker of TMZ resistance in glioma and provided a new strategy to address this challenge. These findings are significant for improving the clinical treatment of glioma in the future.

Endogenous retroviruses are dysregulated in ALS

Amyotrophic lateral sclerosis (ALS) is a universally fatal neurodegenerative disease with no cure. Human endogenous retroviruses (HERVs) have been implicated in its pathogenesis but their relevance to ALS is not fully understood. We examined bulk RNA-seq data from almost 2,000 ALS and unaffected control samples derived from the cortex and spinal cord. Using different methods of feature selection, including differential expression analysis and machine learning, we discovered that transcription of HERV-K loci 1q22 and 8p23.1 were significantly upregulated in the spinal cord of individuals with ALS. Additionally, we identified a subset of ALS patients with upregulated HERV-K expression in the cortex and spinal cord. We also found the expression of HERV-K loci 19q11 and 8p23.1 was correlated with protein coding genes previously implicated in ALS and dysregulated in ALS patients in this study. These results clarify the association of HERV-K and ALS and highlight specific genes in the pathobiology of late-stage ALS.

A Novel Role for the Histone Demethylase JMJD3 in Mediating Heroin-Induced Relapse-Like Behaviors

BACKGROUND

Epigenetic changes that lead to long-term neuroadaptations following opioid exposure are not well understood. We examined how histone demethylase JMJD3 in the nucleus accumbens (NAc) influences heroin seeking after abstinence from self-administration.

METHODS

Male Sprague Dawley rats were trained to self-administer heroin. Western blotting and quantitative polymerase chain reaction were performed to quantify JMJD3 and bone morphogenetic protein (BMP) pathway expression in the NAc (n = 7-11/group). Pharmacological inhibitors or viral expression vectors were microinfused into the NAc to manipulate JMJD3 or the BMP pathway member SMAD1 (n = 9-11/group). The RiboTag capture method (n = 3-5/group) and viral vectors (n = 7-8/group) were used in male transgenic rats to identify the contributions of D1- and D2-expressing medium spiny neurons in the NAc. Drug seeking was tested by cue-induced response previously paired with drug infusion.

RESULTS

Levels of JMJD3 and phosphorylated SMAD1/5 in the NAc were increased after 14 days of abstinence from heroin self-administration. Pharmacological and virus-mediated inhibition of JMJD3 or the BMP pathway attenuated cue-induced seeking. Pharmacological inhibition of BMP signaling reduced JMJD3 expression and H3K27me3 levels. JMJD3 bidirectionally affected seeking: expression of the wild-type increased cue-induced seeking whereas expression of a catalytic dead mutant decreased it. JMJD3 expression was increased in D2+ but not D1+ medium spiny neurons. Expression of the mutant JMJD3 in D2+ neurons was sufficient to decrease cue-induced heroin seeking.

CONCLUSIONS

JMJD3 mediates persistent cellular and behavioral adaptations that underlie heroin relapse, and this activity is regulated by the BMP pathway.

Myeloid-specific KDM6B inhibition sensitizes glioblastoma to PD1 blockade

Glioblastoma (GBM) tumors are enriched in immune-suppressive myeloid cells and are refractory to immune checkpoint therapy (ICT). Targeting epigenetic pathways to reprogram the functional phenotype of immune-suppressive myeloid cells to overcome resistance to ICT remains unexplored. Single-cell and spatial transcriptomic analyses of human GBM tumors demonstrated high expression of an epigenetic enzyme-histone 3 lysine 27 demethylase (KDM6B)-in intratumoral immune-suppressive myeloid cell subsets. Importantly, myeloid cell-specific Kdm6b deletion enhanced proinflammatory pathways and improved survival in GBM tumor-bearing mice. Mechanistic studies showed that the absence of Kdm6b enhances antigen presentation, interferon response and phagocytosis in myeloid cells by inhibition of mediators of immune suppression including Mafb, Socs3 and Sirpa. Further, pharmacological inhibition of KDM6B mirrored the functional phenotype of Kdm6b-deleted myeloid cells and enhanced anti-PD1 efficacy. This study thus identified KDM6B as an epigenetic regulator of the functional phenotype of myeloid cell subsets and a potential therapeutic target for enhanced response to ICT.

Histone Demethylase Modulation: Epigenetic Strategy to Combat Cancer Progression

Epigenetic modifications are heritable, reversible changes in histones or the DNA that control gene functions, being exogenous to the genomic sequence itself. Human diseases, particularly cancer, are frequently connected to epigenetic dysregulations. One of them is histone methylation, which is a dynamically reversible and synchronously regulated process that orchestrates the three-dimensional epigenome, nuclear processes of transcription, DNA repair, cell cycle, and epigenetic functions, by adding or removing methylation groups to histones. Over the past few years, reversible histone methylation has become recognized as a crucial regulatory mechanism for the epigenome. With the development of numerous medications that target epigenetic regulators, epigenome-targeted therapy has been used in the treatment of malignancies and has shown meaningful therapeutic potential in preclinical and clinical trials. The present review focuses on the recent advances in our knowledge on the role of histone demethylases in tumor development and modulation, in emphasizing molecular mechanisms that control cancer cell progression. Finally, we emphasize current developments in the advent of new molecular inhibitors that target histone demethylases to regulate cancer progression.

Combination Treatment of a Phytochemical and a Histone Demethylase Inhibitor-A Novel Approach towards Targeting TGFβ-Induced EMT, Invasion, and Migration in Prostate Cancer

Minimizing side effects, overcoming cancer drug resistance, and preventing metastasis of cancer cells are of growing interest in current cancer therapeutics. Phytochemicals are being researched in depth as they are protective to normal cells and have fewer side effects. Hesperetin is a citrus bioflavonoid known to inhibit TGFβ-induced epithelial-to-mesenchymal transition (EMT), migration, and invasion of prostate cancer cells. Targeting epigenetic modifications that cause cancer is another class of upcoming therapeutics, as these changes are reversible. Global H3K27me3 levels have been found to be reduced in invasive prostate adenocarcinomas. Combining a demethylase inhibitor and a known anti-cancer phytochemical is a unique approach to targeting cancer to attain the aforementioned objectives. In the current study, we used an H3K27 demethylase (JMJD3/KDM6B) inhibitor to study its effects on TGFβ-induced EMT in prostate cancer cells. We then gave a combined hesperetin and GSK-J4 treatment to the PC-3 and LNCaP cells. There was a dose-dependent increase in cytotoxicity and inhibition of TGFβ-induced migration and invasion of prostate cancer cells after GSK-J4 treatment. GSK-J4 not only induced trimethylation of H3K27 but also induced the trimethylation of H3K4. Surprisingly, there was a reduction in the H3K9me3 levels. GSK-J4 alone and a combination of hesperetin and GSK-J4 treatment effectively inhibit the important hallmarks of cancer, such as cell proliferation, migration, and invasion, by altering the epigenetic landscape of cancer cells.

The Chromatin-Oxygen Sensor Gene KDM5C Associates with Novel Hypoxia-Related Signatures in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is a fatal brain tumor without effective drug treatment. In this study, we highlight, for the first time, the contribution of chromatin remodeling gene Lysine (K)-specific demethylase 5C (KDM5C) in GBM via an extensive analysis of clinical, expression, and functional data, integrated with publicly available omic datasets. The expression analysis on GBM samples (N = 37) revealed two informative subtypes, namely KDM5C^High and KDM5C^Low, displaying higher/lower KDM5C levels compared to the controls. The former subtype displays a strong downregulation of brain-derived neurotrophic factor (BDNF)—a negative KDM5C target—and a robust overexpression of hypoxia-inducible transcription factor-1A (HIF1A) gene, a KDM5C modulator. Additionally, a significant co-expression among the prognostic markers HIF1A, Survivin, and p75 was observed. These results, corroborated by KDM5C overexpression and hypoxia-related functional assays in T98G cells, suggest a role for the HIF1A-KDM5C axis in the hypoxic response in this tumor. Interestingly, fluorescence-guided surgery on GBM sections further revealed higher KDM5C and HIF1A levels in the tumor rim niche compared to the adjacent tumor margin, indicating a regionally restricted hyperactivity of this regulatory axis. Analyzing the TCGA expression and methylation data, we found methylation changes between the subtypes in the genes, accounting for the hypoxia response, stem cell differentiation, and inflammation. High NANOG and IL6 levels highlight a distinctive stem cell-like and proinflammatory signature in the KDM5C^High subgroup and GBM niches. Taken together, our results indicate HIF1A-KDM5C as a new, relevant cancer axis in GBM, opening a new, interesting field of investigation based on KDM5C as a potential therapeutic target of the hypoxic microenvironment in GBM.

JMJD family proteins in cancer and inflammation

The occurrence of cancer entails a series of genetic mutations that favor uncontrollable tumor growth. It is believed that various factors collectively contribute to cancer, and there is no one single explanation for tumorigenesis. Epigenetic changes such as the dysregulation of enzymes modifying DNA or histones are actively involved in oncogenesis and inflammatory response. The methylation of lysine residues on histone proteins represents a class of post-translational modifications. The human Jumonji C domain-containing (JMJD) protein family consists of more than 30 members. The JMJD proteins have long been identified with histone lysine demethylases (KDM) and histone arginine demethylases activities and thus could function as epigenetic modulators in physiological processes and diseases. Importantly, growing evidence has demonstrated the aberrant expression of JMJD proteins in cancer and inflammatory diseases, which might serve as an underlying mechanism for the initiation and progression of such diseases. Here, we discuss the role of key JMJD proteins in cancer and inflammation, including the intensively studied histone lysine demethylases, as well as the understudied group of JMJD members. In particular, we focused on epigenetic changes induced by each JMJD member and summarized recent research progress evaluating their therapeutic potential for the treatment of cancer and inflammatory diseases.

Therapeutic potential of inhibiting histone 3 lysine 27 demethylases: a review of the literature

Histone 3 lysine 27 (H3K27) demethylation constitutes an important epigenetic mechanism of gene activation. It is mediated by the Jumonji C domain-containing lysine demethylases KDM6A and KDM6B, both of which have been implicated in a wide myriad of diseases, including blood and solid tumours, autoimmune and inflammatory disorders, and infectious diseases. Here, we review and summarise the pre-clinical evidence, both in vitro and in vivo, in support of the therapeutic potential of inhibiting H3K27-targeting demethylases, with a focus on the small-molecule inhibitor GSK-J4. In malignancies, KDM6A/B inhibition possesses the ability to inhibit proliferation, induce apoptosis, promote differentiation, and heighten sensitivity to currently employed chemotherapeutics. KDM6A/B inhibition also comprises a potent anti-inflammatory approach in inflammatory and autoimmune disorders associated with inappropriately exuberant inflammatory and autoimmune responses, restoring immunological homeostasis to inflamed tissues. With respect to infectious diseases, KDM6A/B inhibition can suppress the growth of infectious pathogens and attenuate the immunopathology precipitated by these pathogens. The pre-clinical in vitro and in vivo data, summarised in this review, suggest that inhibiting H3K27 demethylases holds immense therapeutic potential in many diseases.

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.

KDM6B epigenetically regulated-interleukin-6 expression in the dorsal root ganglia and spinal dorsal horn contributes to the development and maintenance of neuropathic pain following peripheral nerve injury in male rats

The lysine specific demethylase 6B (KDM6B) has been implicated as a coregulator in the expression of proinflammatory mediators, and in the pathogenesis of inflammatory and arthritic pain. However, the role of KDM6B in neuropathic pain has yet to be studied. In the current study, the neuropathic pain was determined by assessing the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) following lumbar 5 spinal nerve ligation (SNL) in male rats. Immunohistochemistry, Western blotting, qRT-PCR, and chromatin immunoprecipitation (ChIP)-PCR assays were performed to investigate the underlying mechanisms. Our results showed that SNL led to a significant increase in KDM6B mRNA and protein in the ipsilateral L4/5 dorsal root ganglia (DRG) and spinal dorsal horn; and this increase correlated a markedly reduction in the level of H3K27me3 methylation in the same tissue. Double immunofluorescence staining revealed that the KDM6B expressed in myelinated A- and unmyelinated C-fibers in the DRG; and located in neuronal cells, astrocytes, and microglia in the dorsal horn. Behavioral data showed that SNL-induced mechanical allodynia and thermal hyperalgesia were impaired by the treatment of prior to i.t. injection of GSK-J4, a specific inhibitor of KDM6B, or KDM6B siRNA. Both microinjection of AAV2-EGFP-KDM6B shRNA in the lumbar 5 dorsal horn and sciatic nerve, separately, alleviated the neuropathic pain following SNL. The established neuropathic pain was also partially attenuated by repeat i.t. injections of GSK-J4 or KDM6B siRNA, started on day 7 after SNL. SNL also resulted in a remarkable increased expression of interleukin-6 (IL-6) in the DRG and dorsal horn. But this increase was dramatically inhibited by i.t. injection of GSK-J4 and KDM6B siRNA; and suppressed by prior to microinjection of AAV2-EGFP-KDM6B shRNA in the dorsal horn and sciatic nerve. Results of ChIP-PCR assay showed that SNL-induced enhanced binding of STAT3 with IL-6 promoter was inhibited by prior to i.t. injection of GSK-J4. Meanwhile, the level of H3K27me3 methylation was also decreased by the treatment. Together, our results indicate that SNL-induced upregulation of KDM6B via demethylating H3K27me3 facilitates the binding of STAT3 with IL-6 promoter, and subsequently mediated-increase in the expression of IL-6 in the DRG and dorsal horn contributes to the development and maintenance of neuropathic pain. Targeting KDM6B might a promising therapeutic strategy to treatment of chronic pain.

The inhibitors of KDM4 and KDM6 histone lysine demethylases enhance the anti-growth effects of erlotinib and HS-173 in head and neck cancer cells

Novel therapeutics are required to improve treatment outcomes in head and neck squamous cell carcinoma (HNSCC) patients. Histone lysine demethylases (KDM) have emerged recently as new potential drug targets for HNSCC therapy. They might also potentiate the action of the inhibitors of EGFR and PI3K signaling pathways. This study aimed at evaluating the anti-cancer effects of KDM4 (ML324) and KDM6 (GSK-J4) inhibitors and their combinations with EGFR (erlotinib) and PI3K (HS-173) inhibitors in HNSCC cells. The effect of the inhibitors on the viability of CAL27 and FaDu cells was evaluated using resazurin assay. The effect of the chemicals on cell cycle and apoptosis was assessed using propidium iodide and Annexin V staining, respectively. The effect of the compounds on gene expression was determined using qPCR and Western blot. The changes in cell cycle distribution upon treatment with the compounds were small to moderate, with the exception of erlotinib, which induced G1 arrest. However, all the compounds and their combinations induced apoptosis in both cell lines. These effects were associated with changes in the level of expression of CDKN1A, CCND1 and BIRC5. The inhibition of KDM4 and KDM6 using ML324 and GSK-J4, respectively, can be regarded as a novel therapeutic strategy in HNSCC.

The Impact of Epigenetic Modifications on Adaptive Resistance Evolution in Glioblastoma

Glioblastoma (GBM) is a highly lethal cancer that is universally refractory to the standard multimodal therapies of surgical resection, radiation, and chemotherapy treatment. Temozolomide (TMZ) is currently the best chemotherapy agent for GBM, but the durability of response is epigenetically dependent and often short-lived secondary to tumor resistance. Therapies that can provide synergy to chemoradiation are desperately needed in GBM. There is accumulating evidence that adaptive resistance evolution in GBM is facilitated through treatment-induced epigenetic modifications. Epigenetic alterations of DNA methylation, histone modifications, and chromatin remodeling have all been implicated as mechanisms that enhance accessibility for transcriptional activation of genes that play critical roles in GBM resistance and lethality. Hence, understanding and targeting epigenetic modifications associated with GBM resistance is of utmost priority. In this review, we summarize the latest updates on the impact of epigenetic modifications on adaptive resistance evolution in GBM to therapy.

Lysine Demethylases: Promising Drug Targets in Melanoma and Other Cancers

Epigenetic dysregulation has been implicated in a variety of pathological processes including carcinogenesis. A major group of enzymes that influence epigenetic modifications are lysine demethylases (KDMs) also known as "erasers" which remove methyl groups on lysine (K) amino acids of histones. Numerous studies have implicated aberrant lysine demethylase activity in a variety of cancers, including melanoma. This review will focus on the structure, classification and functions of KDMs in normal biology and the current knowledge of how KDMs are deregulated in cancer pathogenesis, emphasizing our interest in melanoma. We highlight the current knowledge gaps of KDMs in melanoma pathobiology and describe opportunities to increases our understanding of their importance in this disease. We summarize the progress of several pre-clinical compounds that inhibit KDMs and represent promising candidates for further investigation in oncology.

Potential new targets and drugs related to histone modifications in glioma treatment

Glioma accounts for 40-50% of craniocerebral tumors, whose outcome rarely improves after standard treatment. The development of new therapeutic targets for glioma treatment has important clinical significance. With the deepening of research on gliomas, recent researchers have found that the occurrence and development of gliomas is closely associated with histone modifications, including methylation, acetylation, phosphorylation, and ubiquitination. Additionally, evidence has confirmed the close relationship between histone modifications and temozolomide (TMZ) resistance. Therefore, histone modification-related proteins have been widely recognized as new therapeutic targets for glioma treatment. In this review, we summarize the potential histone modification-associated targets and related drugs for glioma treatment. We have further clarified how histone modifications regulate the pathogenesis of gliomas and the mechanism of drug action, providing novel insights for the current clinical glioma treatment. Herein, we have also highlighted the limitations of current clinical therapies and have suggested future research directions and expected advances in potential areas of disease prognosis. Due to the complicated glioma pathogenesis, in the present review, we have acknowledged the limitations of histone modification applications in the related clinical treatment.

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.

Glioma stem cells and their roles within the hypoxic tumor microenvironment

Tumor microenvironments are the result of cellular alterations in cancer that support unrestricted growth and proliferation and result in further modifications in cell behavior, which are critical for tumor progression. Angiogenesis and therapeutic resistance are known to be modulated by hypoxia and other tumor microenvironments, such as acidic stress, both of which are core features of the glioblastoma microenvironment. Hypoxia has also been shown to promote a stem-like state in both non-neoplastic and tumor cells. In glial tumors, glioma stem cells (GSCs) are central in tumor growth, angiogenesis, and therapeutic resistance, and further investigation of the interplay between tumor microenvironments and GSCs is critical to the search for better treatment options for glioblastoma. Accordingly, we summarize the impact of hypoxia and acidic stress on GSC signaling and biologic phenotypes, and potential methods to inhibit these pathways.

[Association of JMJD3, MMP-2 and VEGF expressions with clinicopathological features of invasive ductal breast carcinoma]

OBJECTIVE

To examine the expressions of JMJD3, matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) in invasive ductal breast carcinoma, their association with the clinicopathological features of the patients and the effect of JMJD3 overexpression on proliferation and MMP-2 and VEGF expressions in breast cancer cells.

METHODS

The protein and mRNA expressions of JMJD3, MMP-2, and VEGF in invasive ductal breast carcinoma and paired adjacent tissues were detected by immunohistochemistry and RT-PCR, respectively, and their correlation with the clinicopathological characteristics of the patients was analyzed. Kaplan-Meier survival analysis was used to evaluate the correlation of JMJD3, MMP-2 and VEGF expression levels with the survival of the patients. In breast cancer MDA-MB-231 cells transfected with a JMJD3-expression plasmid, the expression of Ki67 was examined immunohistochemically, the cell proliferation was assessed with CCK8 assay, and the mRNA expressions of MMP-2 and VEGF were detected with RT-PCR.

RESULTS

Breast cancer tissues had significantly lower JMJD3 expression and higher MMP-2 and VEGF expressions at both the mRNA and protein levels than the adjacent tissue (P < 0.05). The positivity rates of JMJD3, MMP-2 and VEGF in breast cancer tissues were significantly correlated with tumor diameter, differentiation, TNM stage, lymph node metastasis, and molecular subtypes (P < 0.05). KaplanMeier analysis showed that JMJD3 expression level was positively while MMP-2 and VEGF were inversely correlated with the disease-free survival time of the patients (P < 0.05). Cox regression analysis identified JMJD3, MMP-2, VEGF and tumor differentiation as independent prognostic factors of breast cancer. Spearman correlation analysis suggested a negative correlation of JMJD3 with MMP2 (r=-0.569, P < 0.05) and VEGF (r=-0.533, P < 0.05) and a positive correlation between MMP2 and VEGF (r=0.923, P < 0.05). In MDA-MB-231 cells, overexpression of JMJD3 inhibited the proliferation of MDA-MB-231 cells and the expression of MMP-2 and VEGF.

CONCLUSIONS

The expressions of JMJD3, MMP-2 and VEGF in invasive ductal breast carcinoma are closely correlated to tumor proliferation, invasion, metastasis and prognosis and can be used for prognostic evaluation of breast cancer.

Targeted DNA oxidation by LSD1-SMAD2/3 primes TGF-β1/ EMT genes for activation or repression

The epithelial-to-mesenchymal transition (EMT) is a complex transcriptional program induced by transforming growth factor β1 (TGF-β1). Histone lysine-specific demethylase 1 (LSD1) has been recognized as a key mediator of EMT in cancer cells, but the precise mechanism that underlies the activation and repression of EMT genes still remains elusive. Here, we characterized the early events induced by TGF-β1 during EMT initiation and establishment. TGF-β1 triggered, 30–90 min post-treatment, a nuclear oxidative wave throughout the genome, documented by confocal microscopy and mass spectrometry, mediated by LSD1. LSD1 was recruited with phosphorylated SMAD2/3 to the promoters of prototypic genes activated and repressed by TGF-β1. After 90 min, phospho-SMAD2/3 downregulation reduced the complex and LSD1 was then recruited with the newly synthesized SNAI1 and repressors, NCoR1 and HDAC3, to the promoters of TGF-β1-repressed genes such as the Wnt soluble inhibitor factor 1 gene (WIF1), a change that induced a late oxidative burst. However, TGF-β1 early (90 min) repression of transcription also required synchronous signaling by reactive oxygen species and the stress-activated kinase c-Jun N-terminal kinase. These data elucidate the early events elicited by TGF-β1 and the priming role of DNA oxidation that marks TGF-β1-induced and -repressed genes involved in the EMT.

Targeting CREB in Cancer Therapy: A Key Candidate or One of Many? An Update

Simple Summary

Only 5% of all drug-related targets currently move from preclinical to clinical in cancer, and just some of them achieve patient’s bedside. Among others, intratumor heterogeneity and preclinical cancer model limitations actually represent the main reasons for this failure. Cyclic-AMP response element-binding protein (CREB) has been defined as a proto-oncogene in different tumor types, being involved in maintenance and progression. Due to its relevance in tumor pathophysiology, many CREB inhibitor compounds have been developed and tested over the years. Herein, we examine the current state-of-the-art of both CREB and CREB inhibitors in cancer, retracing some of the most significant findings of the last years. While the scientific statement confers on CREB a proactive role in cancer, its therapeutic potential is still stuck at laboratory bench. Therefore, pursuing every concrete result to achieve CREB inhibition in clinical might give chance and future to cancer patients worldwide.

Abstract

Intratumor heterogeneity (ITH) is considered the major disorienting factor in cancer treatment. As a result of stochastic genetic and epigenetic alterations, the appearance of a branched evolutionary shape confers tumor plasticity, causing relapse and unfavorable clinical prognosis. The growing evidence in cancer discovery presents to us “the great paradox” consisting of countless potential targets constantly discovered and a small number of candidates being effective in human patients. Among these, cyclic-AMP response element-binding protein (CREB) has been proposed as proto-oncogene supporting tumor initiation, progression and metastasis. Overexpression and hyperactivation of CREB are frequently observed in cancer, whereas genetic and pharmacological CREB downregulation affects proliferation and apoptosis. Notably, the present review is designed to investigate the feasibility of targeting CREB in cancer therapy. In particular, starting with the latest CREB evidence in cancer pathophysiology, we evaluate the advancement state of CREB inhibitor design, including the histone lysine demethylases JMJD3/UTX inhibitor GSKJ4 that we newly identified as a promising CREB modulator in leukemia cells. Moreover, an accurate analysis of strengths and weaknesses is also conducted to figure out whether CREB can actually represent a therapeutic candidate or just one of the innumerable preclinical cancer targets.

Targeted inhibition of KDM6 histone demethylases eradicates tumor-initiating cells via enhancer reprogramming in colorectal cancer

Tumor-initiating cells (TICs) maintain heterogeneity within tumors and seed metastases at distant sites, contributing to therapeutic resistance and disease recurrence. In colorectal cancer (CRC), strategy that effectively eradicates TICs and is of potential value for clinical use still remains in need. Methods: The anti-tumorigenic activity of a small-molecule inhibitor of KDM6 histone demethylases named GSK-J4 in CRC was evaluated by in vitro assays and in vivo imaging of xenografted tumors. Sphere formation, flow cytometry analysis of cell surface markers and intestinal organoid formation were performed to examine the impact of GSK-J4 on TIC properties. Transcriptome analysis and global profiling of H3K27ac, H3K27me3, and KDM6A levels by ChIP-seq were conducted to elucidate how KDM6 inhibition reshapes epigenetic landscape and thereby eliminating TICs. Results: GSK-J4 alleviated the malignant phenotypes of CRC cells in vitro and in vivo, sensitized them to chemotherapeutic treatment, and strongly repressed TIC properties and stemness-associated gene signatures in these cells. Mechanistically, KDM6 inhibition induced global enhancer reprogramming with a preferential impact on super-enhancer-associated genes, including some key genes that control stemness in CRC such as ID1. Besides, expression of both Kdm6a and Kdm6b was more abundant in mouse intestinal crypt when compared with upper villus and inhibition of their activities blocked intestinal organoid formation. Finally, we unveiled the power of KDM6B in predicting both the overall survival outcome and recurrence of CRC patients. Conclusions: Our study provides a novel rational strategy to eradicate TICs through reshaping epigenetic landscape in CRC, which might also be beneficial for optimizing current therapeutics.

The KDM Inhibitor GSKJ4 Triggers CREB Downregulation via a Protein Kinase A and Proteasome-Dependent Mechanism in Human Acute Myeloid Leukemia Cells

Acute myeloid leukemia (AML) is a progressive hematopoietic-derived cancer arising from stepwise genetic mutations of the myeloid lineage. cAMP response element-binding protein (CREB) is a nuclear transcription factor, which plays a key role in the multistep process of leukemogenesis, thus emerging as an attractive potential drug target for AML treatment. Since epigenetic dysregulations, such as DNA methylation, histone modifications, as well as chromatin remodeling, are a frequent occurrence in AML, an increasing and selective number of epi-drugs are emerging as encouraging therapeutic agents. Here, we demonstrate that the histone lysine demethylases (KDMs) JMJD3/UTX inhibitor GSKJ4 results in both proliferation decrease and CREB protein downregulation in AML cells. We found that GSKJ4 clearly decreases CREB protein, but not CREB mRNA levels. By cycloheximide assay, we provide evidence that GSKJ4 reduces CREB protein stability; moreover, proteasome inhibition largely counteracts the GSKJ4-induced CREB downregulation. Very interestingly, a rapid CREB phosphorylation at the Ser133 residue precedes CREB protein decrease in response to GSKJ4 treatment. In addition, protein kinase A (PKA) inhibition, but not extracellular signal-regulated kinase (ERK)1/2 inhibition, almost completely prevents both GSKJ4-induced p-Ser133-CREB phosphorylation and CREB protein downregulation. Overall, our study enforces the evidence regarding CREB as a potential druggable target, identifies the small epigenetic molecule GSKJ4 as an “inhibitor” of CREB, and encourages the design of future GSKJ4-based studies for the development of innovative approaches for AML therapy.

GSK-J4 induces cell cycle arrest and apoptosis via ER stress and the synergism between GSK-J4 and decitabine in acute myeloid leukemia KG-1a cells

Background

GSK-J4 is the inhibitor of H3K27me3 demethylase. Recent studies demonstrated that GSK-J4 could affect the proliferation and apoptosis of a variety of cancer cells. However, the effects and underlying mechanisms of GSK-J4 on the proliferation and apoptosis of human acute myeloid leukemia (AML) KG-1a cells have not been explored thoroughly.

Methods

The effect of GSK-J4 on cell proliferation was assessed with CCK8, while cell cycle distribution and apoptosis were analyzed using flow cytometry. The proteins related to cell cycle, cell apoptosis, endoplastic reticulum (ER) stress and PKC-α/p-Bcl2 pathway were detected by Western blotting. The expression level of PKC-α mRNA was measured by quantitative real-time PCR.ER stress inhibitor 4-phenyl butyric acid (4-PBA) was used to explore the role of ER stress in GSK-J4 induced cell-cycle arrest and cell apoptosis. The combination effects of Decitabine and GSK-J4 on KG-1a cells proliferation and apoptosis were also evaluated by CCK8, flow cytometry and immunoblot analysis.

Results

GSK-J4 reduced cell viability and arrested cell cycle progression at the S phase by decreasing the expression of CyclinD1 and CyclinA2 and increasing that of P21. Moreover, GSK-J4 enhanced the expression of apoptosis-related proteins (cle-caspase-9 and bax) and inhibited PKC-a/p-Bcl2 pathway to promote cell apoptosis. In addition, ER stress-related proteins (caspase-12, GRP78 and ATF4) were increased markedly after exposure to GSK-J4. The effects of GSK-J4 on cell cycle, apoptosis and PKC-a/p-Bcl2 pathway were attenuated after treatment with ER stress inhibitor. Furthermore, decitabine could significantly inhibit the proliferation and induce the apoptosis of KG-1a cells after combined treatment with GSK-J4.

Conclusion

Taken together, this study provided evidence that ER stress could regulate the process of GSK-J4-induced cell cycle arrest, cell apoptosis and PKC-α/p-bcl2 pathway inhibition and demonstrated a potential combinatory effect of decitabine and GSK-J4 on leukemic cell proliferation and apoptosis.

Therapeutically targeting head and neck squamous cell carcinoma through synergistic inhibition of LSD1 and JMJD3 by TCP and GSK-J1

BACKGROUND

The histone demethylase LSD1 is a key mediator driving tumorigenesis, which holds potential as a promising therapeutic target. However, treatment with LSD1 inhibitors alone failed to result in complete cancer regression.

METHODS

The synergistic effects of TCP (a LSD1 inhibitor) and GSK-J1 (a JMJD3 inhibitor) against HNSCC were determined in vitro and in preclinical animal models. Genes modulated by chemical agents or siRNAs in HNSCC cells were identified by RNA-seq and further functionally interrogated by bioinformatics approach. Integrative siRNA-mediated gene knockdown, rescue experiment and ChIP-qPCR assays were utilised to characterise the mediators underlying the therapeutic effects conferred by TCP and GSK-J1.

RESULTS

Treatment with TCP and GSK-J1 impaired cell proliferation, induced apoptosis and senescence in vitro, which were largely recapitulated by simultaneous LSD1 and JMJD3 knockdown. Combinational treatment inhibited tumour growth and progression in vivo. Differentially expressed genes modulated by TCP and GSK-J1 were significantly enriched in cell proliferation, apoptosis and cancer-related pathways. SPP1 was identified as the mediator of synergy underlying the pro-apoptosis effects conferred by TCP and GSK-J1. Co-upregulation of LSD1 and JMJD3 associated with worse prognosis in patients with HNSCC.

CONCLUSIONS

Our findings revealed a novel therapeutic strategy of simultaneous LSD1 and JMJD3 inhibition against HNSCC.

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.

Targeting of Histone Demethylases KDM5A and KDM6B Inhibits the Proliferation of Temozolomide-Resistant Glioblastoma Cells

Lysine histone demethylases (KDMs) are considered potential therapeutic targets in several tumors, including glioblastoma (GB). In particular, KDM5A is involved in the acquisition of temozolomide (TMZ) resistance in adult GB cells and UDX/KDM6B regulates H3K27 methylation, which is involved in the pediatric diffuse intrinsic pontine glioma (DIPG). Synthetic inhibitors of KDM5A (JIB 04 and CPI-455) efficiently block the proliferation of native and TMZ-resistant cells and the KDM6B inhibitor GSK J4 improves survival in a model of DIPG. The aim of our work was to determine if GSK J4 could be effective against GB cells that have acquired TMZ resistance and if it could synergize with TMZ or JIB 04 to increase the clinical utility of these molecules. Standard functional and pharmacological analytical procedures were utilized to determine the efficacy of the molecules under study when used alone or in combination against native GB cells and in a model of drug resistance. The results of this study indicated that although GSK J4 is active against native and TMZ-resistant cells, it does so at a lower efficacy than JIB 04. Drug combination studies revealed that GSK J4, differently from JIB 04, does not synergize with TMZ. Interestingly, GSK J4 and JIB 04 strongly synergize and are a potent combination against TMZ-resistant cells. Further studies in animal models will be necessary to determine if this combination of molecules might foster the development of novel therapeutic approaches for glioblastoma.

Assessment of epigenetic mechanisms and DNA double-strand break repair using laser micro-irradiation technique developed for hematological cells

Background

Certain tumors rely heavily on their DNA repair capability to survive the DNA damage induced by chemotherapeutic agents. Therefore, it is important to monitor the dynamics of DNA repair in patient samples during the course of their treatment, in order to determine whether a particular drug regimen perturbs the DNA repair networks in cancer cells and provides therapeutic benefits. Quantitative measurement of proteins and/or their posttranslational modification(s) at DNA double strand breaks (DSBs) induced by laser microirradiation provides an applicable diagnostic approach to examine DNA repair and its dynamics. However, its use is restricted to adherent cell lines and not employed in suspension tumor cells that include the many hematological malignancies.

Methods

Here, we report the development of an assay to laser micro-irradiate and quantitatively measure DNA repair transactions at DSB sites in normal mononuclear cells and a variety of suspension leukemia and lymphoma cells including primary patient samples.

Findings

We show that global changes in the H3K27me3-ac switch modulated by inhibitors of Class I HDACs, EZH2 methyltransferase and (or) H3K27me3 demethylases do not reflect the dynamic changes in H3K27me3 that occur at double-strand break sites during DNA repair.

Interpretation

Results from our mechanistic studies and proof-of-principle data with patient samples together show the effectiveness of using the modified micro-laser-based assay to examine DNA repair directly in suspension cancer cells, and has important clinical implications by serving as a valuable tool to assess drug efficacies in hematological cancer cells that grow in suspension.

Comprehensive profiling of JMJD3 in gastric cancer and its influence on patient survival

Histone methylation is thought to control the regulation of genetic program and the dysregulation of it has been found to be closely associated with cancer. JMJD3 has been identified as an H3K27 demethylase and its role in cancer development is context specific. The role of JMJD3 in gastric cancer (GC) has not been examined. In this study, JMJD3 expression was determined. The prognostic significance of JMJD3 and its association with clinical parameters were evaluated. JMJD3 dysregulation mechanism and targets were analyzed. The effect of JMJD3 mutation was determined by functional study. Results showed that JMJD3 was overexpressed in different patient cohorts and also by bioinformatics analysis. High JMJD3 expression was correlated with shortened overall survival in patients with GC and was an independent prognosis predictor. Genetic aberration and DNA methylation might be involved in the deregulation of JMJD3 in GC. Downstream network of JMJD3 was analyzed and several novel potential targets were identified. Furthermore, functional study discovered that both demethylase-dependent and demethylase-independent mechanisms were involved in the oncogenic role of JMJD3 in GC. Importantly, histone demethylase inhibitor GSK-J4 could reverse the oncogenic effect of JMJD3 overexpression. In conclusion, our study report the oncogenic role of JMJD3 in GC for the first time. JMJD3 might serve as an important epigenetic therapeutic target and/or prognostic predictor in GC.

The histone H3 Lys 27 demethylase KDM6B promotes migration and invasion of glioma cells partly by regulating the expression of SNAI1

The histone demethylase KDM6B, also known as jumonji domain-containing protein 3 (JMJD3), is an epigenetic regulator which plays important roles in immune activation, tissue regeneration, cellular senescence and cancer metastasis. But, the role of KDM6B in glioma metastasis is poorly understood. In this study, we achieved transcriptional regulation of KDM6B in glioma cells using CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa). Our results showed that KDM6B promotes the proliferation, migration and invasion of human glioblastoma cells U87 and U251 using CCK8, scratch and transwell assays. Further results indicated that KDM6B increases the expression of SNAI1, a key factor of epithelial-mesenchymal transition (EMT). KDM6B catalyzes the demethylation of histone H3 Lys 27 trimethylation (H3K27me3) in the promoter of SNAI1, which is important for SNAI1 upregulation. Taken together, these findings provide new insight into the mechanism by which KDM6B promotes glioma metastasis.

Brain Tumors of Glial Origin

Gliomas are a heterogeneous group of tumors with evolving classification based on genotype. Isocitrate dehydrogenase (IDH) mutation is an early event in the formation of some diffuse gliomas, and is the best understood mechanism of their epigenetic dysregulation. Glioblastoma may evolve from lower-grade lesions with IDH mutations, or arise independently from copy number changes in platelet-derived growth factor receptor alpha (PDGFRA) and phosphatase and tensin homolog (PTEN). Several molecular subtypes of glioblastoma arise from a common proneural precursor with a tendency toward transition to a mesenchymal subtype. Following oncogenic transformation, gliomas escape growth arrest through a distinct step of aberrant telomere reverse transcriptase (TERT) expression, or mutations in either alpha thalassemia/mental retardation syndrome (ATRX) or death-domain associated protein (DAXX) genes. Metabolic reprogramming allows gliomas to thrive in harsh microenvironments such as hypoxia, acidity, and nutrient depletion, which contribute to tumor initiation, maintenance, and treatment resistance.

Epigenetic Targeting of Glioblastoma

Glioblastoma is one of the first tumors where the biological changes accompanying a single epigenetic modification, the methylation of the MGMT gene, were found to be of clinical relevance. The exploration of the epigenomic landscape of glioblastoma has allowed to identify patients carrying a diffuse hypermethylation at gene promoters and with better outcome. Epigenetic and genetic data have led to the definition of major subgroups of glioma and were the basis of the current WHO classification of CNS tumors and of a novel classification based solely on DNA methylation data that shows a remarkable diagnostic precision.The reversibility of epigenetic modifications is considered a therapeutic opportunity in many tumors also because these alterations have been mechanistically linked to the biological characteristics of glioblastoma. Several alterations like IDH1/2 mutations that interfere with "epigenetic modifier" enzymes, the mutations of the histone 3 variants H3.1 and H3.3 that alter the global H3K27me3 levels and the altered expression of histone methyltransferases and demethylases are considered potentially druggable targets in glioma and molecules targeting these alterations are being tested in preclinical and clinical trials. The recent advances on the knowledge of the players of the "epigenetic orchestra" and of their mutual interactions are indicating new paths that may eventually open new therapeutic options for this invariably lethal cancer.

Forskolin Sensitizes Human Acute Myeloid Leukemia Cells to H3K27me2/3 Demethylases GSKJ4 Inhibitor via Protein Kinase A

Acute myeloid leukemia (AML) is an aggressive hematological malignancy occurring very often in older adults, with poor prognosis depending on both rapid disease progression and drug resistance occurrence. Therefore, new therapeutic approaches are demanded. Epigenetic marks play a relevant role in AML. GSKJ4 is a novel inhibitor of the histone demethylases JMJD3 and UTX. To note GSKJ4 has been recently shown to act as a potent small molecule inhibitor of the proliferation in many cancer cell types. On the other hand, forskolin, a natural cAMP raising compound, used for a long time in traditional medicine and considered safe also in recent studies, is emerging as a very interesting molecule for possible use in cancer therapy. Here, we investigate the effects of forskolin on the sensitivity of human leukemia U937 cells to GSKJ4 through flow cytometry-based assays (cell-cycle progression and cell death), cell number counting, and immunoblotting experiments. We provide evidence that forskolin markedly potentiates GSKJ4-induced antiproliferative effects by apoptotic cell death induction, accompanied by a dramatic BCL2 protein down-regulation as well as caspase 3 activation and PARP protein cleavage. Comparable effects are observed with the phosphodiesterase inhibitor IBMX and 8-Br-cAMP analogous, but not by using 8-pCPT-2'-O-Me-cAMP Epac activator. Moreover, the forskolin-induced enhancement of sensitivity to GSKJ4 is counteracted by pre-treatment with Protein Kinase A (PKA) inhibitors. Altogether, our data strongly suggest that forskolin sensitizes U937 cells to GSKJ4 inhibitor via a cAMP/PKA-mediated mechanism. Our findings provide initial evidence of anticancer activity induced by forskolin/GSKJ4 combination in leukemia cells and underline the potential for use of forskolin and GSKJ4 in the development of innovative and effective therapeutic approaches for AML treatment.

Small Molecule GSK-J1 Affects Differentiation of Specific Neuronal Subtypes in Developing Rat Retina

Histone post-translational modification has been shown to play a pivotal role in regulating gene expression and fate determination during the development of the central nervous system. Application of pharmacological blockers that control histone methylation status has been considered a promising avenue to control abnormal developmental processes and diseases as well. In this study, we focused on the role of potent histone demethylase inhibitor GSK-J1 as a blocker of Jumonji domain-containing protein 3 (Jmjd3) in early postnatal retinal development. Jmjd3 participates in different processes such as cell proliferation, apoptosis, differentiation, senescence, and cell reprogramming via demethylation of histone 3 lysine 27 trimethylation status (H3K27 me3). As a first approach, we determined the localization of Jmjd3 in neonate and adult rat retina. We observed that Jmjd3 accumulation is higher in the adult retina, which is consistent with the localization in the differentiated neurons, including ganglion cells in the retina of neonate rats. At this developmental age, we also observed the presence of Jmjd3 in undifferentiated cells. Also, we confirmed that GSK-J1 caused the increase in the H3k27 me3 levels in the retinas of neonate rats. We next examined the functional consequences of GSK-J1 treatment on retinal development. Interestingly, injection of GSK-J1 simultaneously increased the number of proliferative and apoptotic cells. Furthermore, an increased number of immature cells were detected in the outer plexiform layer, with longer neuronal processes. Finally, the influence of GSK-J1 on postnatal retinal cytogenesis was examined. Interestingly, GSK-J1 specifically caused a significant decrease in the number of PKCα-positive cells, which is a reliable marker of rod-on bipolar cells, showing no significant effects on the differentiation of other retinal subtypes. To our knowledge, these data provide the first evidence that in vivo pharmacological blocking of histone demethylase by GSK-J1 affects differentiation of specific neuronal subtypes. In summary, our results indisputably revealed that the application of GSK-J1 could influence cell proliferation, maturation, apoptosis induction, and specific cell determination. With this, we were able to provide evidence that this small molecule can be explored in therapeutic strategies for the abnormal development and diseases of the central nervous system.