Histone Demethylase KDM4C Stimulates the Proliferation of Prostate Cancer Cells via Activation of AKT and c-Myc

Targeting N-Methyl-lysine Histone Demethylase KDM4 in Cancer: Natural Products Inhibitors as a Driving Force for Epigenetic Drug Discovery

KDM4A-F enzymes are a subfamily of histone demethylases containing the Jumonji C domain (JmjC) using Fe(II) and 2-oxoglutarate for their catalytic function. Overexpression or deregulation of KDM4 enzymes is associated with various cancers, altering chromatin structure and causing transcriptional dysfunction. As KDM4 enzymes have been associated with malignancy, they may represent novel targets for developing innovative therapeutic tools to treat different solid and blood tumors. KDM4A is the isozyme most frequently associated with aggressive phenotypes of these tumors. To this aim, industrial and academic medicinal chemistry efforts have identified different KDM4 inhibitors. Industrial and academic efforts in medicinal chemistry have identified numerous KDM4 inhibitors, primarily pan-KDM4 inhibitors, though they often lack selectivity against other Jumonji family members. The pharmacophoric features of the inhibitors frequently include a chelating group capable of coordinating the catalytic iron within the active site of the KDM4 enzyme. Nonetheless, non-chelating compounds have also demonstrated promising inhibitory activity, suggesting potential flexibility in the drug design. Several natural products, containing monovalent or bivalent chelators, have been identified as KDM4 inhibitors, albeit with a micromolar inhibition potency. This highlights the potential for leveraging them as templates for the design and synthesis of new derivatives, exploiting nature's chemical diversity to pursue more potent and selective KDM4 inhibitors.

2-Oxoglutarate-dependent dioxygenases as oxygen sensors: their importance in health and disease

Since low oxygen conditions below physiological levels, hypoxia, are associated with various diseases, it is crucial to understand the molecular basis behind cellular response to hypoxia. Hypoxia-inducible factors (HIFs) have been revealed to primarily orchestrate the hypoxic response at the transcription level and have continuously attracted great attention over the past three decades. In addition to these hypoxia-responsive effector proteins, 2-oxoglutarate-dependent dioxygenase (2-OGDD) superfamily including prolyl-4-hydroxylase domain-containing proteins (PHDs) and factor inhibiting HIF-1 (FIH-1) has attracted even greater attention in recent years as factors that act as direct oxygen sensors due to their necessity of oxygen for the regulation of the expression and activity of the regulatory subunit of HIFs. Herein, we present a detailed classification of 2-OGDD superfamily proteins, such as Jumonji C-domain-containing histone demethylases, ten-eleven translocation enzymes, AlkB family of DNA/RNA demethylases and lysyl hydroxylases, and discuss their specific functions and associations with various diseases. By introducing the multifaceted roles of 2-OGDD superfamily proteins in the hypoxic response, this review aims to summarize the accumulated knowledge about the complex mechanisms governing cellular adaptation to hypoxia in various physiological and pathophysiological contexts.

Unraveling the role of long non-coding RNAs in therapeutic resistance in acute myeloid leukemia: New prospects & challenges

Acute Myeloid Leukemia (AML) is a fatal hematological disease characterized by the unchecked proliferation of immature myeloid blasts in different tissues developed by various mutations in hematopoiesis. Despite intense chemotherapeutic regimens, patients often experience poor outcomes, leading to substandard remission rates. In recent years, long non-coding RNAs (lncRNAs) have increasingly become important prognostic and therapeutic hotspots, due to their contributions to dysregulating many functional epigenetic, transcriptional, and post-translational mechanisms leading to alterations in cell expressions, resulting in increased chemoresistance and reduced apoptosis in leukemic cells. Through this review, I highlight and discuss the latest advances in understanding the major mechanisms through which lncRNAs confer therapy resistance in AML. In addition, I also provide perspective on the current strategies to target lncRNA expressions. A better knowledge of the critical role that lncRNAs play in controlling treatment outcomes in AML will help improve existing medications and devise new ones.

Implications of c-Myc in the pathogenesis and treatment efficacy of urological cancers

Urological cancers, including prostate, bladder, and renal cancers, are significant causes of death and negatively impact the quality of life for patients. The development and progression of these cancers are linked to the dysregulation of molecular pathways. c-Myc, recognized as an oncogene, exhibits abnormal levels in various types of tumors, and current evidence supports the therapeutic targeting of c-Myc in cancer treatment. This review aims to elucidate the role of c-Myc in driving the progression of urological cancers. c-Myc functions to enhance tumorigenesis and has been documented to increase growth and metastasis in prostate, bladder, and renal cancers. Furthermore, the dysregulation of c-Myc can result in a diminished response to therapy in these cancers. Non-coding RNAs, β-catenin, and XIAP are among the regulators of c-Myc in urological cancers. Targeting and suppressing c-Myc therapeutically for the treatment of these cancers has been explored. Additionally, the expression level of c-Myc may serve as a prognostic factor in clinical settings.

Association of ESR1 germline variants with TP53 somatic variants in breast tumors in a genome-wide study

Background

In breast tumors, somatic mutation frequencies in TP53 and PIK3CA vary by tumor subtype and ancestry. HER2 positive and triple negative breast cancers (TNBC) have a higher frequency of TP53 somatic mutations than other subtypes. PIK3CA mutations are more frequently observed in hormone receptor positive tumors. Emerging data suggest tumor mutation status is associated with germline variants and genetic ancestry. We aimed to identify germline variants that are associated with somatic TP53 or PIK3CA mutation status in breast tumors.

Methods

A genome-wide association study was conducted using breast cancer mutation status of TP53 and PIK3CA and functional mutation categories including TP53 gain of function (GOF) and loss of function mutations and PIK3CA activating/hotspot mutations. The discovery analysis consisted of 2850 European ancestry women from three datasets. Germline variants showing evidence of association with somatic mutations were selected for validation analyses based on predicted function, allele frequency, and proximity to known cancer genes or risk loci. Candidate variants were assessed for association with mutation status in a multi-ancestry validation study, a Malaysian study, and a study of African American/Black women with TNBC.

Results

The discovery Germline x Mutation (GxM) association study found five variants associated with one or more TP53 phenotypes with P values <1×10-6, 33 variants associated with one or more TP53 phenotypes with P values <1×10-5, and 44 variants associated with one or more PIK3CA phenotypes with P values <1×10-5. In the multi-ancestry and Malaysian validation studies, germline ESR1 locus variant, rs9383938, was associated with the presence of TP53 mutations overall (P values 6.8×10-5 and 9.8×10-8, respectively) and TP53 GOF mutations (P value 8.4×10-6). Multiple variants showed suggestive evidence of association with PIK3CA mutation status in the validation studies, but none were significant after correction for multiple comparisons.

Conclusions

We found evidence that germline variants were associated with TP53 and PIK3CA mutation status in breast cancers. Variants near the estrogen receptor alpha gene, ESR1, were significantly associated with overall TP53 mutations and GOF mutations. Larger multi-ancestry studies are needed to confirm these findings and determine if these variants contribute to ancestry-specific differences in mutation frequency.

TACH101, a first-in-class pan-inhibitor of KDM4 histone demethylase

Histone lysine demethylase 4 (KDM4) is an epigenetic regulator that facilitates the transition between transcriptionally silent and active chromatin states by catalyzing the removal of methyl groups on histones H3K9, H3K36, and H1.4K26. KDM4 overamplification or dysregulation has been reported in various cancers and has been shown to drive key processes linked to tumorigenesis, such as replicative immortality, evasion of apoptosis, metastasis, DNA repair deficiency, and genomic instability. KDM4 also plays a role in epigenetic regulation of cancer stem cell renewal and has been linked to more aggressive disease and poorer clinical outcomes. The KDM4 family is composed of four main isoforms (KDM4A-D) that demonstrate functional redundancy and cross-activity; thus, selective inhibition of one isoform appears to be ineffective and pan-inhibition targeting multiple KDM4 isoforms is required. Here, we describe TACH101, a novel, small-molecule pan-inhibitor of KDM4 that selectively targets KDM4A-D with no effect on other KDM families. TACH101 demonstrated potent antiproliferative activity in cancer cell lines and organoid models derived from various histologies, including colorectal, esophageal, gastric, breast, pancreatic, and hematological malignancies. In vivo , potent inhibition of KDM4 led to efficient tumor growth inhibition and regression in several xenograft models. A reduction in the population of tumor-initiating cells was observed following TACH101 treatment. Overall, these observations demonstrate the broad applicability of TACH101 as a potential anticancer agent and support its advancement into clinical trials.

The phosphorylation to acetylation/methylation cascade in transcriptional regulation: how kinases regulate transcriptional activities of DNA/histone-modifying enzymes

Transcription factors directly regulate gene expression by recognizing and binding to specific DNA sequences, involving the dynamic alterations of chromatin structure and the formation of a complex with different kinds of cofactors, like DNA/histone modifying-enzymes, chromatin remodeling factors, and cell cycle factors. Despite the significance of transcription factors, it remains unclear to determine how these cofactors are regulated to cooperate with transcription factors, especially DNA/histone modifying-enzymes. It has been known that DNA/histone modifying-enzymes are regulated by post-translational modifications. And the most common and important modification is phosphorylation. Even though various DNA/histone modifying-enzymes have been classified and partly explained how phosphorylated sites of these enzymes function characteristically in recent studies. It still needs to find out the relationship between phosphorylation of these enzymes and the diseases-associated transcriptional regulation. Here this review describes how phosphorylation affects the transcription activity of these enzymes and other functions, including protein stability, subcellular localization, binding to chromatin, and interaction with other proteins.

Bioinformatics analysis of prognostic value and immunological role of MeCP2 in pan-cancer

Methyl-CpG-binding protein 2(MeCP2) is an important epigenetic regulatory factor that promotes many tumor developments, such as liver cancer, breast cancer, and colorectal cancer. So far, no pan-cancer analysis has been reported. Therefore, this study aims to explore pan-cancer's prognostic value, immune infiltration pattern, and biological function. We used bioinformatics methods to analyze the expression and prognostic significance of MeCP2, and the relationship between MeCP2 and clinicopathological parameters, genetic variation, methylation, phosphorylation, immune cell infiltration, and biological function in pan-cancer from using a public database. The results showed that expression of MeCP2 was up-regulated in 8 cancers and down-regulated in 2 cancers, which was remarkably correlated with the prognosis, pathological stage, grade and subtype of cancers. The promoter methylation level of MeCP2 DNA was decreased in bladder urothelial carcinoma (BLCA), breast invasive carcinoma (BRCA), liver hepatocellular carcinoma (LIHC), prostate adenocarcinoma (PRAD), uterine corpus endometrial carcinoma (UCEC), testicular germ cell tumors (TGCT), and stomach adenocarcinoma (STAD);decreased phosphorylation of S25, S90, S92, S241, S286, S325 and S435 was found in MeCP2, such as UCEC, lung adenocarcinoma (LUAD), ovarian serous cystadenocarcinoma (OV), colon adenocarcinoma (COAD), and kidney renal clear cell carcinoma (KIRC). Furthermore, MeCP2 expression was significantly associated with multiple immunomodulators and immune cell infiltration levels across most tumors. Therefore, our pan-cancer explored the prognostic markers and immunotherapeutic value of MeCP2 in different cancers.

Roles and regulation of histone acetylation in hepatocellular carcinoma

Hepatocellular Carcinoma (HCC) is the most frequent malignant tumor of the liver, but its prognosis is poor. Histone acetylation is an important epigenetic regulatory mode that modulates chromatin structure and transcriptional status to control gene expression in eukaryotic cells. Generally, histone acetylation and deacetylation processes are controlled by the opposing activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Dysregulation of histone modification is reported to drive aberrant transcriptional programmes that facilitate liver cancer onset and progression. Emerging studies have demonstrated that several HDAC inhibitors exert tumor-suppressive properties via activation of various cell death molecular pathways in HCC. However, the complexity involved in the epigenetic transcription modifications and non-epigenetic cellular signaling processes limit their potential clinical applications. This review brings an in-depth view of the oncogenic mechanisms reported to be related to aberrant HCC-associated histone acetylation, which might provide new insights into the effective therapeutic strategies to prevent and treat HCC.

Natural product myricetin is a pan-KDM4 inhibitor which with poly lactic-co-glycolic acid formulation effectively targets castration-resistant prostate cancer

Background

Castration-resistant prostate cancer (CRPC) with sustained androgen receptor (AR) signaling remains a critical clinical challenge, despite androgen depletion therapy. The Jumonji C-containing histone lysine demethylase family 4 (KDM4) members, KDM4A‒KDM4C, serve as critical coactivators of AR to promote tumor growth in prostate cancer and are candidate therapeutic targets to overcome AR mutations/alterations-mediated resistance in CRPC.

Methods

In this study, using a structure-based approach, we identified a natural product, myricetin, able to block the demethylation of histone 3 lysine 9 trimethylation by KDM4 members and evaluated its effects on CRPC. A structure-based screening was employed to search for a natural product that inhibited KDM4B. Inhibition kinetics of myricetin was determined. The cytotoxic effect of myricetin on various prostate cancer cells was evaluated. The combined effect of myricetin with enzalutamide, a second-generation AR inhibitor toward C4-2B, a CRPC cell line, was assessed. To improve bioavailability, myricetin encapsulated by poly lactic-co-glycolic acid (PLGA), the US food and drug administration (FDA)-approved material as drug carriers, was synthesized and its antitumor activity alone or with enzalutamide was evaluated using in vivo C4-2B xenografts.

Results

Myricetin was identified as a potent α-ketoglutarate-type inhibitor that blocks the demethylation activity by KDM4s and significantly reduced the proliferation of both androgen-dependent (LNCaP) and androgen-independent CRPC (CWR22Rv1 and C4-2B). A synergistic cytotoxic effect toward C4-2B was detected for the combination of myricetin and enzalutamide. PLGA-myricetin, enzalutamide, and the combined treatment showed significantly greater antitumor activity than that of the control group in the C4-2B xenograft model. Tumor growth was significantly lower for the combination treatment than for enzalutamide or myricetin treatment alone.

Conclusions

These results suggest that myricetin is a pan-KDM4 inhibitor and exhibited potent cell cytotoxicity toward CRPC cells. Importantly, the combination of PLGA-encapsulated myricetin with enzalutamide is potentially effective for CRPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00812-3.

Transcriptomic and Drug Discovery Analyses Reveal Natural Compounds Targeting the KDM4 Subfamily as Promising Adjuvant Treatments in Cancer

KDM4 proteins are a subfamily of histone demethylases that target the trimethylation of lysines 9 and 36 of histone H3, which are associated with transcriptional repression and elongation respectively. Their deregulation in cancer may lead to chromatin structure alteration and transcriptional defects that could promote malignancy. Despite that KDM4 proteins are promising drug targets in cancer therapy, only a few drugs have been described as inhibitors of these enzymes, while studies on natural compounds as possible inhibitors are still needed. Natural compounds are a major source of biologically active substances and many are known to target epigenetic processes such as DNA methylation and histone deacetylation, making them a rich source for the discovery of new histone demethylase inhibitors. Here, using transcriptomic analyses we determined that the KDM4 family is deregulated and associated with a poor prognosis in multiple neoplastic tissues. Also, by molecular docking and molecular dynamics approaches, we screened the COCONUT database to search for inhibitors of natural origin compared to FDA-approved drugs and DrugBank databases. We found that molecules from natural products presented the best scores in the FRED docking analysis. Molecules with sugars, aromatic rings, and the presence of OH or O- groups favor the interaction with the active site of KDM4 subfamily proteins. Finally, we integrated a protein-protein interaction network to correlate data from transcriptomic analysis and docking screenings to propose FDA-approved drugs that could be used as multitarget therapies or in combination with the potential natural inhibitors of KDM4 enzymes. This study highlights the relevance of the KDM4 family in cancer and proposes natural compounds that could be used as potential therapies.

Lysine Demethylase 6B Regulates Prostate Cancer Cell Proliferation by Controlling c-MYC Expression

Elevated expression of lysine demethylase 6A (KDM6A) and lysine demethylase 6B (KDM6B) has been reported in prostate cancer (PCa). However, the mechanism underlying the specific role of KDM6A/B in PCa is still fragmentary. Here, we report novel KDM6A/B downstream targets involved in controlling PCa cell proliferation. KDM6A and KDM6B mRNAs were higher in prostate adenocarcinoma, lymph node metastatic site (LNCaP) but not in prostate adenocarcinoma, bone metastatic site (PC3) and prostate adenocarcinoma, brain metastatic site (DU145) cells. Higher KDM6A mRNA was confirmed at the protein level. A metastasis associated gene focused oligonucleotide array was performed to identify KDM6A/B dependent genes in LNCaP cells treated with a KDM6 family selective inhibitor, ethyl-3-(6-(4,5-dihydro-1H-benzo[d]azepin-3(2H)-yl)-2-(pyridin-2-yl)pyrimidin-4-ylamino)propanoate (GSK-J4). This identified five genes [V-myc myelocytomatosis viral oncogene homolog (avian) (c-MYC), neurofibromin 2 (merlin) (NF2), C-terminal binding protein 1 (CTBP1), EPH receptor B2 (EPHB2), and plasminogen activator urokinase receptor (PLAUR)] that were decreased more than 50% by GSK-J4, and c-MYC was the most downregulated gene. Array data were validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR), which detected a reduction in c-MYC steady state mRNA and prespliced mRNA, indicative of transcriptional repression of c-MYC gene expression. Furthermore, c-MYC protein was also decreased by GSK-J4. Importantly, GSK-J4 reduced mRNA and protein levels of c-MYC target gene, cyclinD1 (CCND1). Silencing of KDM6A/B with small interfering RNA (siRNA) confirmed that expression of both c-MYC and CCND1 are dependent on KDM6B. Phosphorylated retinoblastoma (pRb), a marker of G1 to S-phase transition, was decreased by GSK-J4 and KDM6B silencing. GSK-J4 treatment resulted in a decrease in cell proliferation and cell number, detected by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay and conventional cell counting, respectively. Consequently, we conclude that KDM6B controlling c-MYC, CCND1, and pRb contribute regulation of PCa cell proliferation, which represents KDM6B as a promising epigenetic target for the treatment of advanced PCa. SIGNIFICANCE STATEMENT: Lysine demethylase 6A (KDM6A) and 6B (KDM6B) were upregulated in prostate cancer (PCa). We reported novel KDM6A/B downstream targets controlling proliferation. Amongst 84 metastasis associated genes, V-myc myelocytomatosis viral oncogene homolog (avian) (c-MYC) was the most inhibited gene by KDM6 inhibitor, ethyl-3-(6-(4,5-dihydro-1H-benzo[d]azepin-3(2H)-yl)-2-(pyridin-2-yl)pyrimidin-4-ylamino)propanoate (GSK-J4). This was accompanied by decreased c-MYC targets, cyclinD1 (CCND1) and phosphorylated retinoblastoma (pRb), which were KDM6B dependent. GSK-J4 decreased proliferation and cell counting. We conclude that KDM6B controlling c-MYC, CCND1, and pRb contribute regulation of PCa proliferation.

Exploring anti-androgen therapies in hormone dependent prostate cancer and new therapeutic routes for castration resistant prostate cancer

Androgen deprivation therapies (ADTs) are important treatments which inhibit androgen-induced prostate cancer (PCa) progression by either preventing androgen biosynthesis (e.g. abiraterone) or by antagonizing androgen receptor (AR) function (e.g. bicalutamide, enzalutamide, darolutamide). A major limitation of current ADTs is they often remain effective for limited durations after which patients commonly progress to a lethal and incurable form of PCa, called castration-resistant prostate cancer (CRPC) where the AR continues to orchestrate pro-oncogenic signalling. Indeed, the increasing numbers of ADT-related treatment-emergent neuroendocrine-like prostate cancers (NePC), which lack AR and are thus insensitive to ADT, represents a major therapeutic challenge. There is therefore an urgent need to better understand the mechanisms of AR action in hormone dependent disease and the progression to CRPC, to enable the development of new approaches to prevent, reverse or delay ADT-resistance. Interestingly the AR regulates distinct transcriptional networks in hormone dependent and CRPC, and this appears to be related to the aberrant function of key AR-epigenetic coregulator enzymes including the lysine demethylase 1 (LSD1/KDM1A). In this review we summarize the current best status of anti-androgen clinical trials, the potential for novel combination therapies and we explore recent advances in the development of novel epigenetic targeted therapies that may be relevant to prevent or reverse disease progression in patients with advanced CRPC.

Protective Role of 4-(4-Hydroxy-3-methoxyphenyl)-2-Butanone on Prostatic Cells Hyperplasia of Rats and Human, 5α-reductase Inhibition Pathway

BACKGROUND

Prostate gland is an exocrine gland that could be affected by various pathological conditions. Benign prostatic hyperplasia (BPH) is an age-dependent medical condition caused by increased activity of 5α-reductase enzyme (5α-R). Medical treatment by finasteride is considered during treatment, but it has unavoidable side effects. Hence, there is an increasing need to use natural ingredients for BPH treatment. Gingerol oil (ginger extract) is transferred by heating into zingerone. Recent studies reported the effect of zingerone on prostate cancer cells.

AIMS AND OBJECTIVES

The aim of the present research is to investigate the protective effect of zingerone against BPH.

MATERIALS AND METHODS

Sixty male Albino Wistar rats were divided into three groups: control group, prostatic hyperplasia group treated with saline, and prostatic hyperplasia group treated with zingerone (PH-Z-G). At day 28, all rats were sacrificed, epididymis and prostate samples were collected for histopathological examination and Western blotting for androgen receptors (ARs) proteins and steroid 5 alpha-reductase 1 (SRD5A1). Human RWPE-1 prostatic cell line was assessed for viability and cycle after treated with zingerone 500 μg/day for 10 days.

RESULTS

PH-S group showed significant (P < 0.05) thickening of connective tissue septa associated with narrowing of acinar lumen. PH-Z group showed regain of the normal histological feature. SRD5A1 and AR expression was significantly (P < 0.05) reduced in PH-Z group in comparison with PH-S group. Cell line proliferation was significantly reduced after application of zingerone with G2/M cell cycle arrest.

CONCLUSION

Our results showed that natural herbal zingerone decreased the prostatic tissue levels of (5α reductase and AR) in rat BPH model, which could be a promising herbal medicine for BPH treatment. Further human clinical trials are required.

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.

KDM4C contributes to cytarabine resistance in acute myeloid leukemia via regulating the miR-328-3p/CCND2 axis through MALAT1

Aims

Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm, in which relapse due to drug resistance is the main cause for treatment failure and the disease progression. In this study, we aimed to investigate the molecular mechanism of KDM4C-dependent MALAT1/miR-328-3p/CCND2 axis in cytarabine (Ara-C) resistance in the context of AML.

Methods

Bioinformatics analysis was performed to predict the targeting relationships among KDM4C, MALAT1, miR-328-3p, and CCND2 in AML, which were validated with chromatin immunoprecipitation and dual-luciferase reporter assay. Methylation-specific polymerase chain reaction was conducted to detect the methylation of MALAT1 promoter. After conducting gain- and loss-of-function assays, we investigated the effect of KDM4C on cell Ara-C resistance. A NOD/SCID mouse model was established to further investigate the roles of KDM4C/MALAT1/miR-328-3p/CCND2 in Ara-C resistant AML cells.

Results

KDM4C expression was upregulated in AML. KDM4C upregulation promoted the demethylation in the promoter region of MALAT1 to increase its expression, MALAT1 targeted and inhibited miR-328-3p expression, enhancing the Ara-C resistance of HL-60/A. miR-328-3p targeted and suppressed the expression of CCND2 in HL-60/A to inhibit the Ara-C resistance. Mechanistically, KDM4C regulated miR-328-3p/CCND2 through MALAT1, resulting in Ara-C resistance in AML. Findings in an in vivo xenograft NOD/SCID mouse model further confirmed the contribution of KDM4C/MALAT1/miR-328-3p/CCND2 in the Ara-C resistant AML.

Conclusion

Our study demonstrated that KDM4C may up-regulate MALAT1 expression, which decreases the expression of miR-328-3p. The downregulation of miR-328-3p increased the level of CCND2, which induced the Ara-C resistance in AML.

Novel germline variant in the histone demethylase and transcription regulator KDM4C induces a multi-cancer phenotype

Background

Genes involved in epigenetic regulation are central for chromatin structure and gene expression. Specific mutations in these might promote carcinogenesis in several tissue types.

Methods

We used exome, whole-genome and Sanger sequencing to detect rare variants shared by seven affected individuals in a striking early-onset multi-cancer family. The only variant that segregated with malignancy resided in a histone demethylase KDM4C. Consequently, we went on to study the epigenetic landscape of the mutation carriers with ATAC, ChIP (chromatin immunoprecipitation) and RNA-sequencing from lymphoblastoid cell lines to identify possible pathogenic effects.

Results

A novel variant in KDM4C, encoding a H3K9me3 histone demethylase and transcription regulator, was found to segregate with malignancy in the family. Based on Roadmap Epigenomics Project data, differentially accessible chromatin regions between the variant carriers and controls enrich to normally H3K9me3-marked chromatin. We could not detect a difference in global H3K9 trimethylation levels. However, carriers of the variant seemed to have more trimethylated H3K9 at transcription start sites. Pathway analyses of ChIP-seq and differential gene expression data suggested that genes regulated through KDM4C interaction partner EZH2 and its interaction partner PLZF are aberrantly expressed in mutation carriers.

Conclusions

The apparent dysregulation of H3K9 trimethylation and KDM4C-associated genes in lymphoblastoid cells supports the hypothesis that the KDM4C variant is causative of the multi-cancer susceptibility in the family. As the variant is ultrarare, located in the conserved catalytic JmjC domain and predicted pathogenic by the majority of available in silico tools, further studies on the role of KDM4C in cancer predisposition are warranted.

Targeting KDM4B that coactivates c-Myc-regulated metabolism to suppress tumor growth in castration-resistant prostate cancer

Rationale: The progression of prostate cancer (PCa) to castration-resistant PCa (CRPC) despite continuous androgen deprivation therapy is a major clinical challenge. Over 90% of patients with CRPC exhibit sustained androgen receptor (AR) signaling. KDM4B that removes the repressive mark H3K9me3/2 is a transcriptional activator of AR and has been implicated in the development of CRPC. However, the mechanisms of KDM4B involvement in CRPC remain largely unknown. Here, we sought to demonstrate the molecular pathway mediated by KDM4B in CRPC and to provide proof-of-concept evidence that KDM4B is a potential CRPC target. Methods: CRPC cells (C4-2B or CWR22Rv1) depleted with KDM4B followed by cell proliferation (in vitro and xenograft), microarray, qRT-PCR, Seahorse Flux, and metabolomic analyses were employed to identify the expression and metabolic profiles mediated by KDM4B. Immunoprecipitation was used to determine the KDM4B-c-Myc interaction region. Reporter activity assay and ChIP analysis were used to characterize the KDM4B-c-Myc complex-mediated mechanistic actions. The clinical relevance between KDM4B and c-Myc was determined using UCSC Xena analysis and immunohistochemistry. Results: We showed that KDM4B knockdown impaired CRPC proliferation, switched Warburg to OXPHOS metabolism, and suppressed gene expressions including those targeted by c-Myc. We further demonstrated that KDM4B physically interacted with c-Myc and they were co-recruited to the c-Myc-binding sequence on the promoters of metabolic genes (LDHA, ENO1, and PFK). Importantly, KDM4B and c-Myc synergistically promoted the transactivation of the LDHA promoter in a demethylase-dependent manner. We also provided evidence that KDM4B and c-Myc are co-expressed in PCa tissue and that high expression of both is associated with worse clinical outcome. Conclusions: KDM4B partners with c-Myc and serves as a coactivator of c-Myc to directly enhance c-Myc-mediated metabolism, hence promoting CRPC progression. Targeting KDM4B is thus an alternative therapeutic strategy for advanced prostate cancers driven by c-Myc and AR.

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.

Histone lysine demethylases and their functions in cancer

Histone lysine demethylases (KDMs) are enzymes that remove the methylation marks on lysines in nucleosomes' histone tails. These changes in methylation marks regulate gene transcription during both development and malignant transformation. Depending on which lysine residue is targeted, the effect of a given KDM on gene transcription can be either activating or repressing, and KDMs can regulate the expression of both oncogenes and tumour suppressors. Thus, the functions of KDMs can be regarded as both oncogenic and tumour suppressive, contingent on cell context and the enzyme isoform. Finally, KDMs also demethylate nonhistone proteins and have a variety of demethylase-independent functions. These epigenetic and other mechanisms that KDMs control make them important regulators of malignant tumours. Here, we present an overview of eight KDM subfamilies, their most-studied lysine targets and selected recent data on their roles in cancer stem cells, tumour aggressiveness and drug tolerance.

C-Myc Signaling Pathway in Treatment and Prevention of Brain Tumors

Brain tumors are responsible for high morbidity and mortality worldwide. Several factors such as the presence of blood-brain barrier (BBB), sensitive location in the brain, and unique biological features challenge the treatment of brain tumors. The conventional drugs are no longer effective in the treatment of brain tumors, and scientists are trying to find novel therapeutics for brain tumors. In this way, identification of molecular pathways can facilitate finding an effective treatment. c-Myc is an oncogene signaling pathway capable of regulation of biological processes such as apoptotic cell death, proliferation, survival, differentiation, and so on. These pleiotropic effects of c-Myc have resulted in much fascination with its role in different cancers, particularly brain tumors. In the present review, we aim to demonstrate the upstream and down-stream mediators of c-Myc in brain tumors such as glioma, glioblastoma, astrocytoma, and medulloblastoma. The capacity of c-Myc as a prognostic factor in brain tumors will be investigated. Our goal is to define an axis in which the c-Myc signaling pathway plays a crucial role and to provide direction for therapeutic targeting in these signaling networks in brain tumors.

The use of zebrafish model in prostate cancer therapeutic development and discovery

Zebrafish is now among the leading in vivo model for cancer research, including prostate cancer. They are an alternative economic model being used to study cancer development, proliferation, and metastasis. They can also be effectively utilized for the development of cancer drugs at all levels, including target validation, and high-throughput screening for possible lead molecules. In this review, we provide a comprehensive overview of the role of zebrafish as an in vivo model in prostate cancer research. Globally, prostate cancer is a leading cause of death in men. Although many molecular mechanisms have been identified as playing a role in the pathogenesis of prostate cancer, there is still a significant need to understand the initial events of the disease. Furthermore, current treatments are limited by the emergence of severe toxicities and multidrug resistance. There is an essential need for economical and relevant research tools to improve our understanding and overcome these problems. This review provides a comprehensive summary of studies that utilized zebrafish for different aims in prostate cancer research. We discuss the use of zebrafish in prostate cancer cell proliferation and metastasis, defining signaling pathways, drug discovery and therapeutic development against prostate cancer, and toxicity studies. Finally, this review highlights limitations in this field and future directions to efficiently use zebrafish as a robust model for prostate cancer therapeutics development.

LncRNA MNX1-AS1 promotes progression of intrahepatic cholangiocarcinoma through the MNX1/Hippo axis

Long non-coding RNAs (lncRNAs) have extremely complex roles in the progression of intrahepatic cholangiocarcinoma (ICC) and remain to be elucidated. By cytological and animal model experiments, this study demonstrated that the expression of lncRNA MNX1-AS1 was remarkably elevated in ICC cell lines and tissues, and was highly and positively correlated with motor neuron and pancreas homeobox protein 1 (MNX1) expression. MNX1-AS1 significantly facilitated the proliferation, migration, invasion, and angiogenesis in ICC cells in vitro, and remarkably promoted tumor growth and metastasis in vivo. Further study revealed that MNX1-AS1 promoted the expression of MNX1 via recruiting transcription factors c-Myc and myc-associated zinc finger protein (MAZ). Furthermore, MNX1 upregulated the expression of Ajuba protein via binding to its promoter region, and subsequently, Ajuba protein suppressed the Hippo signaling pathway. Taken together, our results uncovered that MNX1-AS1 can facilitate ICC progression via MNX1-AS1/c-Myc and MAZ/MNX1/Ajuba/Hippo pathway, suggesting that MNX1-AS1 may be able to serve as a potential target for ICC treatment.

MAGE-C2/CT10 promotes growth and metastasis through upregulating c-Myc expression in prostate cancer

Prostate cancer (PC) is the most common reproductive cancer in men and the third leading cause of cancer death among men worldwide. Recently targeted therapy showed a significant therapeutic effect on PC, whereas finding more PC therapeutic target is still urgently needed. Melanoma-associated antigen-encoding C2 (MAGE-C2/CT10), which have significant homology with the MAGE-C1/CT-7 gene, was known to be involved in the development of a variety of tumors. However, the role and mechanism of MAGE-C2/CT10 in prostate cancer remains unclear. Herein, we found the high levels of MAGE-C2/CT10 in highly metastatic prostate cancer. Our findings confirmed that the depletion of MAGE-C2/CT10 suppressed the growth of PC cells, and restrained PC cell migration and invasion in vitro. We noticed MAGE-C2/CT10 could stimulate c-Myc expression via FBP1, and further contributed to PC cell proliferation and motility. Performing in vivo assays, we demonstrated MAGE-C2/CT10 promoted tumor growth and metastasis of PC cells in mice. Collectively, we found the abnormal expression of MAGE-C2/CT10 in PC, and revealed the regulatory mechanism underlying MAGE-C2/CT10 promoting PC progression and metastasis.