Lysine methyltransferase 2D regulates pancreatic carcinogenesis through metabolic reprogramming

Identification of methylation driver genes for predicting the prognosis of pancreatic cancer patients based on whole-genome DNA methylation sequencing technology

This study was based on the use of whole-genome DNA methylation sequencing technology to identify DNA methylation biomarkers in tumor tissue that can predict the prognosis of patients with pancreatic cancer (PCa). TCGA database was used to download PCa-related DNA methylation and transcriptome atlas data. Methylation driver genes (MDGs) were obtained using the MethylMix package. Candidate genes in the MDGs were screened for prognostic relevance to PCa patients by univariate Cox analysis, and a prognostic risk score model was constructed based on the key MDGs. ROC curve analysis was performed to assess the accuracy of the prognostic risk score model. The effects of PIK3C2B knockdown on malignant phenotypes of PCa cells were investigated in vitro. A total of 2737 differentially expressed genes were identified, with 649 upregulated and 2088 downregulated, using 178 PCa samples and 171 normal samples. MethylMix was employed to identify 71 methylation-driven genes (47 hypermethylated and 24 hypomethylated) from 185 TCGA PCa samples. Cox regression analyses identified eight key MDGs (LEF1, ZIC3, VAV3, TBC1D4, FABP4, MAP3K5, PIK3C2B, IGF1R) associated with prognosis in PCa. Seven of them were hypermethylated, while PIK3C2B was hypomethylated. A prognostic risk prediction model was constructed based on the eight key MDGs, which was found to accurately predict the prognosis of PCa patients. In addition, the malignant phenotypes of PANC-1 cells were decreased after the knockdown of PIK3C2B. Therefore, the prognostic risk prediction model based on the eight key MDGs could accurately predict the prognosis of PCa patients.

Predictive model using four ferroptosis-related genes accurately predicts gastric cancer prognosis

BACKGROUND

Gastric cancer (GC) is a common malignancy of the digestive system. According to global 2018 cancer data, GC has the fifth-highest incidence and the third-highest fatality rate among malignant tumors. More than 60% of GC are linked to infection with Helicobacter pylori (H. pylori), a gram-negative, active, microaerophilic, and helical bacterium. This parasite induces GC by producing toxic factors, such as cytotoxin-related gene A, vacuolar cytotoxin A, and outer membrane proteins. Ferroptosis, or iron-dependent programmed cell death, has been linked to GC, although there has been little research on the link between H. pylori infection-related GC and ferroptosis.

AIM

To identify coregulated differentially expressed genes among ferroptosis-related genes (FRGs) in GC patients and develop a ferroptosis-related prognostic model with discrimination ability.

METHODS

Gene expression profiles of GC patients and those with H. pylori-associated GC were obtained from The Cancer Genome Atlas and Gene Expression Omnibus (GEO) databases. The FRGs were acquired from the FerrDb database. A ferroptosis-related gene prognostic index (FRGPI) was created using least absolute shrinkage and selection operator–Cox regression. The predictive ability of the FRGPI was validated in the GEO cohort. Finally, we verified the expression of the hub genes and the activity of the ferroptosis inducer FIN56 in GC cell lines and tissues.

RESULTS

Four hub genes were identified (NOX4, MTCH1, GABARAPL2, and SLC2A3) and shown to accurately predict GC and H. pylori-associated GC. The FRGPI based on the hub genes could independently predict GC patient survival; GC patients in the high-risk group had considerably worse overall survival than did those in the low-risk group. The FRGPI was a significant predictor of GC prognosis and was strongly correlated with disease progression. Moreover, the gene expression levels of common immune checkpoint proteins dramatically increased in the high-risk subgroup of the FRGPI cohort. The hub genes were also confirmed to be highly overexpressed in GC cell lines and tissues and were found to be primarily localized at the cell membrane. The ferroptosis inducer FIN56 inhibited GC cell proliferation in a dose-dependent manner.

CONCLUSION

In this study, we developed a predictive model based on four FRGs that can accurately predict the prognosis of GC patients and the efficacy of immunotherapy in this population.

Tumor-associated macrophages drive glycolysis through the IL-8/STAT3/GLUT3 signaling pathway in pancreatic cancer progression

Glycolytic metabolism is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and tumor-associated stromal cells play important roles in tumor metabolism. We previously reported that tumor-associated macrophages (TAMs) facilitate PDAC progression. However, little is known about whether TAMs are involved in regulating glycolysis in PDAC. Here, we found a positive correlation between CD68+ TAM infiltration and FDG maximal standardized uptake (FDG SUVmax) on PET-CT images of PDAC. We discovered that the glycolytic gene set was prominently enriched in the high TAM infiltration group through Gene Set Enrichment Analysis using The Cancer Genome Atlas database. Mechanistically, TAMs secreted IL-8 to promote GLUT3 expression in PDAC cells, enhancing tumor glycolysis both in vitro and in vivo, whereas this effect could be blocked by the IL-8 receptor inhibitor reparixin. Furthermore, IL-8 promoted the translocation of phosphorylated STAT3 into the nucleus to activate the GLUT3 promoter. Overall, we demonstrated that TAMs boosted PDAC cell glycolysis through the IL-8/STAT3/GLUT3 signaling pathway. Our cumulative findings suggest that the abrogation of TAM-induced tumor glycolysis by reparixin might exhibit an antitumor impact and offer a potential therapeutic target for PDAC.

Crosstalk between metabolic remodeling and epigenetic reprogramming: A new perspective on pancreatic cancer

Pancreatic cancer is a highly malignant solid tumor with a poor prognosis and a high mortality rate. Thus, exploring the mechanisms underlying the development and progression of pancreatic cancer is critical for identifying targets for diagnosis and treatment. Two important hallmarks of cancer-metabolic remodeling and epigenetic reprogramming-are interconnected and closely linked to regulate one another, creating a complex interaction landscape that is implicated in tumorigenesis, invasive metastasis, and immune escape. For example, metabolites can be involved in the regulation of epigenetic enzymes as substrates or cofactors, and alterations in epigenetic modifications can in turn regulate the expression of metabolic enzymes. The crosstalk between metabolic remodeling and epigenetic reprogramming in pancreatic cancer has gained considerable attention. Here, we review the emerging data with a focus on the reciprocal regulation of metabolic remodeling and epigenetic reprogramming. We aim to highlight how these mechanisms could be applied to develop better therapeutic strategies.

Loss of Claudin-1 incurred by DNMT aberration promotes pancreatic cancer progression

Pancreatic cancer (PC) is one of the most malignant and deadly tumors of digestive system with complex etiology and pathogenesis. Dysregulations of oncogenes and tumor suppressors due to epigenetic modifications causally affect tumorogenesis; however the key tumor suppressors and their regulations in PC are only partially defined. In this study, we found that Claudin-1 (encoded by CLDN1 gene) was significantly suppressed in PC that correlated with a poor clinical prognosis. Claudin-1 knockdown enhanced PC cell proliferation, migration, and stemness. Pancreatic specific Cldn1 knockout in KPC (LSLKrasG12D/Pdx1-Cre/Trp53R172H+) and KC (LSLKrasG12D/Pdx1-Cre) mice reduced mouse survival, promoted acinar-to-ductal metaplasia (ADM) process, and accelerated the development of pancreatic intraepithelial neoplasia (PanIN) and PC. Further investigation revealed that Claudin-1 suppression was mainly caused by aberrant DNA methylatransferase 1 (DNMT1) and DNMT3A elevations and the resultant CLDN1 promoter hypermethylation, as a DNMT specific inhibitor SGI-1027 effectively reversed the Claudin-1 suppression and inhibited PC progression both in vitro and in vivo in a Claudin-1 preservation-dependent manner. Together, our data suggest that Claudin-1 functions as a tumor suppressor in PC and its epigenetic suppression due to DNMT aberrations is a crucial event that promotes PC development and progression.

Epigenetic regulation in cancer

Epigenetic modifications are defined as heritable changes in gene activity that do not involve changes in the underlying DNA sequence. The oncogenic process is driven by the accumulation of alterations that impact genome's structure and function. Genetic mutations, which directly disrupt the DNA sequence, are complemented by epigenetic modifications that modulate gene expression, thereby facilitating the acquisition of malignant characteristics. Principals among these epigenetic changes are shifts in DNA methylation and histone mark patterns, which promote tumor development and metastasis. Notably, the reversible nature of epigenetic alterations, as opposed to the permanence of genetic changes, positions the epigenetic machinery as a prime target in the discovery of novel therapeutics. Our review delves into the complexities of epigenetic regulation, exploring its profound effects on tumor initiation, metastatic behavior, metabolic pathways, and the tumor microenvironment. We place a particular emphasis on the dysregulation at each level of epigenetic modulation, including but not limited to, the aberrations in enzymes responsible for DNA methylation and histone modification, subunit loss or fusions in chromatin remodeling complexes, and the disturbances in higher-order chromatin structure. Finally, we also evaluate therapeutic approaches that leverage the growing understanding of chromatin dysregulation, offering new avenues for cancer treatment.

EBF2 Links KMT2D-Mediated H3K4me1 to Suppress Pancreatic Cancer Progression via Upregulating KLLN

Mono-methylation of histone H3 on Lys 4 (H3K4me1), which is catalyzed by histone-lysine N-methyltransferase 2D (KMT2D), serves as an important epigenetic regulator in transcriptional control. In this study, the authors identify early B-cell factor 2 (EBF2) as a binding protein of H3K4me1. Combining analyses of RNA-seq and ChIP-seq data, the authors further identify killin (KLLN) as a transcriptional target of KMT2D and EBF2 in pancreatic ductal adenocarcinoma (PDAC) cells. KMT2D-dependent H3K4me1 and EBF2 are predominantly over-lapped proximal to the transcription start site (TSS) of KLLN gene. Comprehensive functional assays show that KMT2D and EBF2 cooperatively inhibit PDAC cells proliferation, migration, and invasion through upregulating KLLN. Such inhibition on PDAC progression is also achieved through increasing H3K4me1 level by GSK-LSD1, a selective inhibitor of lysine-specific demethylase 1 (LSD1). Taken together, these findings reveal a new mechanism underlying PDAC progression and provide potential therapeutic targets for PDAC treatment.

Identification of SLC2A3 as a prognostic indicator correlated with the NF-κB/EMT axis and immune response in head and neck squamous cell carcinoma

SLC2A3 is an important member of the glucose transporter superfamily. It has been recently suggested that upregulation of SLC2A3 is associated with poor survival and acts as a prognostic marker in a variety of tumors. Unfortunately, the prognostic role of SLC2A3 in head and neck squamous cell carcinoma (HNSC) is less known. In the present study, we analyzed SLC2A3 expression in HNSC and its correlation with prognosis using TCGA and GEO databases. The results showed that SLC2A3 mRNA expression was higher in HNSC compared with adjacent normal tissues, which was validated with our 9 pairs of HNSC specimens. Moreover, high SLC2A3 expression predicted poor prognosis in HNSC patients. Mechanistically, GSEA revealed that high expression of SLC2A3 was enriched in epithelial-mesenchymal transition (EMT) and NF-κB signaling. In HNSC cell lines, SLC2A3 knockdown inhibited cell proliferation and migration. In addition, NF-κB P65 and EMT-related gene expression was suppressed upon SLC2A3 knockdown, indicating that SLC2A3 may play a preeminent role in the progression of HNSC through the NF-κB/EMT axis. Meanwhile, the expression of SLC2A3 was negatively correlated with immune cells, suggesting that SLC2A3 may be involved in the immune response in HNSC. The correlation between SLC2A3 expression and drug sensitivity was further assessed. In conclusion, our study demonstrated that SLC2A3 could predict the prognosis of HNSC patients and mediate the progression of HNSC via the NF-κB/EMT axis and immune responses.

Epigenetic control of pancreatic cancer metastasis

Surgical resection, when combined with chemotherapy, has been shown to significantly improve the survival rate of patients with pancreatic ductal adenocarcinoma (PDAC). However, this treatment option is only feasible for a fraction of patients, as more than 50% of cases are diagnosed with metastasis. The multifaceted process of metastasis is still not fully understood, but recent data suggest that transcriptional and epigenetic plasticity play significant roles. Interfering with epigenetic reprogramming can potentially control the adaptive processes responsible for metastatic progression and therapy resistance, thereby enhancing treatment responses and preventing recurrence. This review will focus on the relevance of histone-modifying enzymes in pancreatic cancer, specifically on their impact on the metastatic cascade. Additionally, it will also provide a brief update on the current clinical developments in epigenetic therapies.

Diagnosis and prognosis of pancreatic cancer with immunoglobulin heavy constant delta blood marker

BACKGROUND

Pancreatic cancer (PC) is highly malignant and difficult to detect, while few blood markers are currently available for diagnosing PC.

METHODS

We obtained differential expression genes (DEGs) from GEO (gene expression omnibus) database and assessed by quantitative real-time polymerase chain reaction (qRT-PCR), receiver operating characteristic (ROC), univariate and multifactorial regression analysis, and survival analysis in our clinic center. Through the TCGA (the cancer genome atlas) database, we analyzed functional enrichment, different risk groups with survival analysis, immunological features, and the risk score established by the Cox regression model and constructed a nomogram.

RESULT

Immunoglobulin heavy constant delta (IGHD) was remarkably upregulated in peripheral blood from PC patients, and IGHD was a potential independent biomarker for PC diagnosis (ROC sensitivity, 76.0%; specificity, 74.2%; area under the curve (AUC) = 0.817; univariate logistic regression analysis: odds ratio (OR) 1.488; 95% confidence interval (CI) 1.182-1.872; P < 0.001; multiple logistic: OR 2.097; 95% CI 1.276-3.389, P = 0.003). In addition, the IGHD expression was remarkably reduced after resectioning the primary tumor. High IGHD expression indicated higher lymphocyte infiltration and increased activities of immunological pathways in PC patients. KRAS and SMAD were observed with a prominent difference among top mutated genes between the two groups. The risk score predicted reliable clinical prognosis and drug responses. Furthermore, a nomogram with the risk score and clinical characteristics was constructed, showing a better predictive performance.

CONCLUSION

IGHD is a valuable PC diagnosis, prognosis, and therapeutic response marker.

Whole-exome sequencing reveals mutational profiles of anorectal and gynecological melanoma

Mucosal melanoma is a rare and highly malignant type of melanoma. Among the sites that mucosal melanoma arises, anorectal and gynecological melanoma has more aggressive behavior and worse prognosis. There was no effective therapy for mucosal melanoma at present. Only a small number of mucosal melanoma patients which harbor mutations in BRAF or KIT benefit from targeted therapy. So it's an urgent need to identify more actionable mutations in mucosal melanoma. To identify more potential therapeutic targets in mucosal melanoma, 48 samples were collected from 44 patients with anorectal or gynecological melanoma and subjected to whole-exome sequencing. The tumor mutation burden was low with a median of 1.75 mutations per Mb. In chromosomal level, 1q, 6p and 8q of mucosal melanoma were significantly amplified while 9p, 10p, 10q, 16p and 16q were significantly deleted. Muc16 was the most frequently mutated oncogene in our samples(25%). The mutation frequency of KIT(20%) was comparable to the "triple-wild" genes-NRAS(20%), NF1(20%), and BRAF(11%). KMT2D mutation was found in 18.18% patients, which is previously unidentified. MAPK signaling pathway and lysine degradation were the most frequently mutated pathways. Moreover, patients with TP53 mutations tend to have worse clinical outcome (median survival time 19 vs. 50 months, log-rank P = 0.006). 2000 ore mutated genes involved in MAPK signaling pathway were identified, which expand the patients potentially benefit from ample MAPK inhibitors. KMT2D could be a potential therapeutic target. Moreover, TP53 could be a potential prognosis marker for mucosal melanoma.

Heterogeneity and potential therapeutic insights for triple-negative breast cancer based on metabolic-associated molecular subtypes and genomic mutations

Objective: Due to a lack of effective therapy, triple-negative breast cancer (TNBC) is extremely poor prognosis. Metabolic reprogramming is an important hallmark in tumorigenesis, cancer diagnosis, prognosis, and treatment. Categorizing metabolic patterns in TNBC is critical to combat heterogeneity and targeted therapeutics. Methods: 115 TNBC patients from TCGA were combined into a virtual cohort and verified by other verification sets, discovering differentially expressed genes (DEGs). To identify reliable metabolic features, we applied the same procedures to five independent datasets to verify the identified TNBC subtypes, which differed in terms of prognosis, metabolic characteristics, immune infiltration, clinical features, somatic mutation, and drug sensitivity. Results: In general, TNBC could be classified into two metabolically distinct subtypes. C1 had high immune checkpoint genes expression and immune and stromal scores, demonstrating sensitivity to the treatment of PD-1 inhibitors. On the other hand, C2 displayed a high variation in metabolism pathways involved in carbohydrate, lipid, and amino acid metabolism. More importantly, C2 was a lack of immune signatures, with late pathological stage, low immune infiltration and poor prognosis. Interestingly, C2 had a high mutation frequency in PIK3CA, KMT2D, and KMT2C and displayed significant activation of the PI3K and angiogenesis pathways. As a final output, we created a 100-gene classifier to reliably differentiate the TNBC subtypes and AKR1B10 was a potential biomarker for C2 subtypes. Conclusion: In conclusion, we identified two subtypes with distinct metabolic phenotypes, provided novel insights into TNBC heterogeneity, and provided a theoretical foundation for therapeutic strategies.

Metabolic reprogramming and epigenetic modifications in cancer: from the impacts and mechanisms to the treatment potential

Metabolic reprogramming and epigenetic modifications are hallmarks of cancer cells. In cancer cells, metabolic pathway activity varies during tumorigenesis and cancer progression, indicating regulated metabolic plasticity. Metabolic changes are often closely related to epigenetic changes, such as alterations in the expression or activity of epigenetically modified enzymes, which may exert a direct or an indirect influence on cellular metabolism. Therefore, exploring the mechanisms underlying epigenetic modifications regulating the reprogramming of tumor cell metabolism is important for further understanding tumor pathogenesis. Here, we mainly focus on the latest studies on epigenetic modifications related to cancer cell metabolism regulations, including changes in glucose, lipid and amino acid metabolism in the cancer context, and then emphasize the mechanisms related to tumor cell epigenetic modifications. Specifically, we discuss the role played by DNA methylation, chromatin remodeling, noncoding RNAs and histone lactylation in tumor growth and progression. Finally, we summarize the prospects of potential cancer therapeutic strategies based on metabolic reprogramming and epigenetic changes in tumor cells.

Integrated bioinformatics analysis for conducting a prognostic model and identifying immunotherapeutic targets in gastric cancer

BACKGROUND

Gastric cancer is the third leading cause of death from cancer worldwide and has a poor prognosis. Practical risk scores and prognostic models for gastric cancer are lacking. While immunotherapy has succeeded in some cancers, few gastric cancer patients benefit from immunotherapy. Immune genes and the tumor microenvironment (TME) are essential for cancer progression and immunotherapy response. However, the roles of immune genes and the tumor microenvironment in immunotherapy remain unclear. The study aimed to construct a prognostic prediction model and identify immunotherapeutic targets for gastric cancer (GC) patients by exploring immune genes and the tumor microenvironment.

RESULTS

An immune-related risk score (IRRS) model, including APOH, RNASE2, F2R, DEFB126, CXCL6, and CXCL3 genes, was constructed for risk stratification. Patients in the low-risk group, which was characterized by elevated tumor mutation burden (TMB) have higher survival rate. The risk level was remarkably correlated with tumor-infiltrating immune cells (TIICs), the immune checkpoint molecule expression, and immunophenoscore (IPS). CXCL3 and CXCL6 were significantly upregulated in gastric cancer tissues compared with normal tissues using the UALCAN database and RT-qPCR. The nomogram showed good calibration and moderate discrimination in predicting overall survival (OS) at 1-, 3-, and 5- year for gastric cancer patients using risk-level and clinical characteristics.

CONCLUSION

Our findings provided a risk stratification and prognosis prediction tool for gastric cancer patients and further the research into immunotherapy in gastric cancer.

KMT2D links TGF-β signaling to noncanonical activin pathway and regulates pancreatic cancer cell plasticity

Although KMT2D, also known as MLL2, is known to play an essential role in development, differentiation, and tumor suppression, its role in pancreatic cancer development is not well understood. Here, we discovered a novel signaling axis mediated by KMT2D, which links TGF-β to the activin A pathway. We found that TGF-β upregulates a microRNA, miR-147b, which in turn leads to post-transcriptional silencing of KMT2D. Loss of KMT2D induces the expression and secretion of activin A, which activates a noncanonical p38 MAPK-mediated pathway to modulate cancer cell plasticity, promote a mesenchymal phenotype, and enhance tumor invasion and metastasis in mice. We observed a decreased KMT2D expression in human primary and metastatic pancreatic cancer. Furthermore, inhibition or knockdown of activin A reversed the protumoral role of KMT2D loss. These findings support a tumor-suppressive role of KMT2D in pancreatic cancer and identify miR-147b and activin A as novel therapeutic targets.

H3K4me3-related lncRNAs signature and comprehensive analysis of H3K4me3 regulating tumor immunity in lung adenocarcinoma

BACKGROUD

The role of epigenetic modifications in tumorigenesis has been widely reported. However, the role and mechanism of H3K4me3 modification in lung adenocarcinoma (LUAD) are rarely reported systematically. We, therefore, sought to analyze the characteristics of LUAD associated with H3K4me3 modification, build an H3K4me3-lncRNAs score model to predict the prognosis of patients with LUAD and clarify the potential value of H3K4me3 in immunotherapy of LUAD.

METHODS

We evaluated H3K4me3-lncRNA patterns and H3K4me3-lncRNA scores of 477 LUAD samples based on 53 lncRNAs closely correlated to H3K4me3 regulators and comprehensive analyzed the role of these patterns in tumorigenesis and tumor immunity. Using Gene set variation analysis (GSVA), we systematically evaluated the H3K4me3 level of every sample and deeply analyzed the effect of H3K4me3 on the prognosis of LUAD. In addition, we included two independent immunotherapy cohorts to study the impact of high H3K4me3 score on the prognosis of patients. We also used an independent cohort with 52 matched paraffin specimens of LUAD to verify the impact of high H3K3me3 expression on the prognosis of patients.

RESULTS

We identified three H3K4me3-lncRNA patterns that exhibited specific immune characteristics. Characterized by immunosuppressive and increased TGFβ-mediated epithelial-mesenchymal transition (EMT), patients with high H3K4me3-lncRNA score had a poor overall survival and decreased H3K4me3 score. H3K4me3 score was significantly positively correlated with CD4+T-cell and CD8+T-cell activation, programmed cell death and immune checkpoints (ICs) expression, and was negatively correlated with MYC pathway, TP53 pathway, and cell proliferation. Patients with high H3K4me3 score showed elevated expression of ICs, potentiated CD4 T-cell and CD8 T-cell activation, increased programmed cell death, and suppressed cell proliferation and TGFβ-mediated EMT. Patients with high H3K4me3 score and high expression of CTLA4, ICOS, TIGIT, PDCD1LG2, IDO1, CD274, PDCD1, LAG3, or HAVCR2 had the best survival advantage. Two independent immunotherapy cohorts verified that patients with high H3K4me3 score showed an increased inflamed tumor microenvironment (TME) phenotype and enhanced anti-PD-1/L1 immunotherapy response. Immunohistochemistry (IHC) data from 52 matched paraffin specimens of LUAD confirmed that the protein level of H3K4me3 in tumor was significantly lower than that of paracancerous tissues and H3K4me3 brought significant survival benefits to patients with LUAD.

CONCLUSIONS

We build an H3K4me3-lncRNAs score model to predict the prognosis of patients with LUAD. More importantly, this study revealed characteristics of H3K4me3 modification in LUAD and clarified the important potential role of H3K4me3 on tumor immunotherapy and patients' survival.

Histone Modifications Represent a Key Epigenetic Feature of Epithelial-to-Mesenchyme Transition in Pancreatic Cancer

Pancreatic cancer is one of the most lethal malignant diseases due to its high invasiveness, early metastatic properties, rapid disease progression, and typically late diagnosis. Notably, the capacity for pancreatic cancer cells to undergo epithelial-mesenchymal transition (EMT) is key to their tumorigenic and metastatic potential, and is a feature that can explain the therapeutic resistance of such cancers to treatment. Epigenetic modifications are a central molecular feature of EMT, for which histone modifications are most prevalent. The modification of histones is a dynamic process typically carried out by pairs of reverse catalytic enzymes, and the functions of these enzymes are increasingly relevant to our improved understanding of cancer. In this review, we discuss the mechanisms through which histone-modifying enzymes regulate EMT in pancreatic cancer.

KMT2D deficiency drives lung squamous cell carcinoma and hypersensitivity to RTK-RAS inhibition

Lung squamous cell carcinoma (LUSC) represents a major subtype of lung cancer with limited treatment options. KMT2D is one of the most frequently mutated genes in LUSC (>20%), and yet its role in LUSC oncogenesis remains unknown. Here, we identify KMT2D as a key regulator of LUSC tumorigenesis wherein Kmt2d deletion transforms lung basal cell organoids to LUSC. Kmt2d loss increases activation of receptor tyrosine kinases (RTKs), EGFR and ERBB2, partly through reprogramming the chromatin landscape to repress the expression of protein tyrosine phosphatases. These events provoke a robust elevation in the oncogenic RTK-RAS signaling. Combining SHP2 inhibitor SHP099 and pan-ERBB inhibitor afatinib inhibits lung tumor growth in Kmt2d-deficient LUSC murine models and in patient-derived xenografts (PDXs) harboring KMT2D mutations. Our study identifies KMT2D as a pivotal epigenetic modulator for LUSC oncogenesis and suggests that KMT2D loss renders LUSC therapeutically vulnerable to RTK-RAS inhibition.

A narrative review on pathogenetic mechanisms of hyperinsulinemic hypoglycemia in Kabuki syndrome

Objective. Kabuki syndrome (KS) is associated with hyperinsulinemic hypoglycemia (HH) in 0.3-4% of patients, thus exceeding the prevalence in the general population. HH association is stronger for KS type 2 (KDM6A-KS, OMIM #300867) than KS type 1 (KMT2D-KS, OMIM #147920). Both the disease-associated genes, KMD6A and KMT2D, modulate the chromatin dynamic. As such, KS is considered to be the best characterized pediatric chromatinopathy. However, the exact pathogenetic mechanisms leading to HH in this syndrome remain still unclear. Methods. We selected on the electronic database PubMed all articles describing or hypothesizing the mechanisms underlying the dysregulated insulin secretion in KS. Results. The impact on the gene expression due to the KDM6A or KMT2D function loss may lead to a deregulated pancreatic β-cell differentiation during embryogenesis. Moreover, both KMT2D gene and KDM6A gene are implicated in promoting the transcription of essential pancreatic β-cell genes and in regulating the metabolic pathways instrumental for insulin release. Somatic KMT2D or KDM6A mutations have also been described in several tumor types, including insulinoma, and have been associated with metabolic pathways promoting pancreatic cell proliferation. Conclusions. The impact of pathogenic variants in KDM6A and KDM2D genes on β-cell insulin release remains to be fully clarified. Understanding this phenomenon may provide valuable insight into the physiological mechanisms of insulin release and into the pathological cascade causing hyperinsulinism in KS. The identification of these molecular targets may open new therapeutic opportunities based on epigenetic modifiers.

Pan-Cancer Analysis of Histone Methyltransferase KMT2D with Potential Implications for Prognosis and Immunotherapy in Human Cancer

BACKGROUND

Pan-cancer analysis is an efficient tool to obtain a panoramic view of cancer- related genes and identify their oncogenic processes, facilitating the development of new therapeutic targets. Lysine methyltransferase 2D (KMT2D), acting as a major enhancer coactivator for mammalian cells, is one of the most frequently mutated genes across various cancer types and is considered an oncogene and a rationale for epigenetic therapeutic targets.

OBJECTIVE

This study was designed to explore the potential role of KMT2D in human cancer through a pan-cancer analysis.

METHODS

The expression of KMT2D was assessed in normal tissues and cell lines, and pancancers from The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE), and Genotype-Tissue Expression (GTE) datasets were used to explore its correlation with prognosis, immune cell infiltration, tumor mutation burden, microsatellite instability, and mismatch repair.

RESULTS

KMT2D expression was heterogeneous across different cancer types. Increased KMT2D indicated a worse prognosis in adrenocortical carcinoma (ACC), brain lower-grade glioma (LGG), and mesothelioma (MESO), while patients with high KMT2D expression showed better outcomes in renal clear cell carcinoma (KIRC). Moreover, KMT2D expression was positively correlated with immune cell infiltration and negative tumor mutation burden in multiple cancers. In addition, a significant correlation between KMT2D and immune checkpoint-related genes or mismatch repair genes was identified.

CONCLUSIONS

These findings support the hypothesis that KMT2D is not only a potential biomarker for prognosis and immunotherapy response prediction but also an essential immune regulator in human cancer.

Crosstalk between metabolic reprogramming and epigenetics in cancer: updates on mechanisms and therapeutic opportunities

Reversible, spatial, and temporal regulation of metabolic reprogramming and epigenetic homeostasis are prominent hallmarks of carcinogenesis. Cancer cells reprogram their metabolism to meet the high bioenergetic and biosynthetic demands for vigorous proliferation. Epigenetic dysregulation is a common feature of human cancers, which contributes to tumorigenesis and maintenance of the malignant phenotypes by regulating gene expression. The epigenome is sensitive to metabolic changes. Metabolism produces various metabolites that are substrates, cofactors, or inhibitors of epigenetic enzymes. Alterations in metabolic pathways and fluctuations in intermediate metabolites convey information regarding the intracellular metabolic status into the nucleus by modulating the activity of epigenetic enzymes and thus remodeling the epigenetic landscape, inducing transcriptional responses to heterogeneous metabolic requirements. Cancer metabolism is regulated by epigenetic machinery at both transcriptional and post‐transcriptional levels. Epigenetic modifiers, chromatin remodelers and non‐coding RNAs are integral contributors to the regulatory networks involved in cancer metabolism, facilitating malignant transformation. However, the significance of the close connection between metabolism and epigenetics in the context of cancer has not been fully deciphered. Thus, it will be constructive to summarize and update the emerging new evidence supporting this bidirectional crosstalk and deeply assess how the crosstalk between metabolic reprogramming and epigenetic abnormalities could be exploited to optimize treatment paradigms and establish new therapeutic options. In this review, we summarize the central mechanisms by which epigenetics and metabolism reciprocally modulate each other in cancer and elaborate upon and update the major contributions of the interplays between epigenetic aberrations and metabolic rewiring to cancer initiation and development. Finally, we highlight the potential therapeutic opportunities for hematological malignancies and solid tumors by targeting this epigenetic‐metabolic circuit. In summary, we endeavored to depict the current understanding of the coordination between these fundamental abnormalities more comprehensively and provide new perspectives for utilizing metabolic and epigenetic targets for cancer treatment.

LINC00667 Promotes Progression of Esophageal Cancer Cells by Regulating miR-200b-3p/SLC2A3 Axis

BACKGROUND

Recently, more and more evidence indicated that the long non-coding RNA was strictly related to the occurrence and progression of human cancers, including esophageal cancer (EC). We observed that LINC00667 was increased in EC, but the function of LINC00667 was unclear. Therefore, the function and potential molecular mechanism of LINC00667 in the progression of EC need to be further studied.

METHODS

Quantitative real-time PCR was used to investigate the levels of LINC00667, miR-200b-3p, and SLC2A3. The levels of protein involved in cell cycle, cell apoptosis, epithelial-mesenchymal transition, as well as SLC2A3 were quantitatived by western blot. The role of LINC00667 in the proliferative, migratory and invasive capabilities of EC cells were measured by cell counting kit-8 assay, EdU assay, flow cytometry assay, wound healing assay and transwell assay, respectively. Interaction between LINC00667 and miR-200b-3p or miR-200b-3p and SLC2A3 were confirmed using a luciferase reporter assay.

RESULTS

In this work, we found that LINC00667 expression was up-regulated in EC cell lines, and LINC00667 knockdown inhibited cell proliferation, migration, and invasion in EC cells. In addition, it showed that LINC00667 functioned as competitive endogenous RNA for miR-200b-3p by the DIANA-LncBase database. Moreover, we used targetscan online software to predict SLC2A3 as a target gene of miR-200b-3p. Subsequently, rescue experiments confirmed that knocking out SLC2A3 could reverse the inhibitory effect of miR-200b-3p on EC cells transfected with sh-LINC00667.

CONCLUSION

Herein, we revealed the novel mechanism of LINC00667 on regulating metastasis-related gene by sponge regulatory axis during EC metastasis. Our results demonstrated that LINC00667 plays a critical role in metastatic EC by mediating sponge regulatory axis miR-200b-3p/SLC2A3. To explore function of LINC00667/miR-200b-3p/SLC2A3 axis may provide an informative biomarker of malignancy and a highly selective anti-EC therapeutic target.

New dawn for cancer cell death: Emerging role of lipid metabolism

BACKGROUND

Resistance to cell death, a protective mechanism for removing damaged cells, is a "Hallmark of Cancer" that is essential for cancer progression. Increasing attention to cancer lipid metabolism has revealed a number of pathways that induce cancer cell death.

SCOPE OF REVIEW

We summarize emerging concepts regarding lipid metabolic reprogramming in cancer that is mainly involved in lipid uptake and trafficking, de novo synthesis and esterification, fatty acid synthesis and oxidation, lipogenesis, and lipolysis. During carcinogenesis and progression, continuous metabolic adaptations are co-opted by cancer cells, to maximize their fitness to the ever-changing environmental. Lipid metabolism and the epigenetic modifying enzymes interact in a bidirectional manner which involves regulating cancer cell death. Moreover, lipids in the tumor microenvironment play unique roles beyond metabolic requirements that promote cancer progression. Finally, we posit potential therapeutic strategies targeting lipid metabolism to improve treatment efficacy and survival of cancer patient.

MAJOR CONCLUSIONS

The profound comprehension of past findings, current trends, and future research directions on resistance to cancer cell death will facilitate the development of novel therapeutic strategies targeting the lipid metabolism.

Novel Immune-Related Ferroptosis Signature in Esophageal Cancer: An Informatics Exploration of Biological Processes Related to the TMEM161B-AS1/hsa-miR-27a-3p/GCH1 Regulatory Network

Background: Considering the role of immunity and ferroptosis in the invasion, proliferation and treatment of cancer, it is of interest to construct a model of prognostic-related differential expressed immune-related ferroptosis genes (PR-DE-IRFeGs), and explore the ferroptosis-related biological processes in esophageal cancer (ESCA).

Methods: Four ESCA datasets were used to identify three PR-DE-IRFeGs for constructing the prognostic model. Validation of our model was based on analyses of internal and external data sets, and comparisons with past models. With the biological-based enrichment analysis as a guide, exploration for ESCA-related biological processes was undertaken with respect to the immune microenvironment, mutations, competing endogenous RNAs (ceRNA), and copy number variation (CNV). The model’s clinical applicability was measured by nomogram and correlation analysis between risk score and gene expression, and also immune-based and chemotherapeutic sensitivity.

Results: Three PR-DE-IRFeGs (DDIT3, SLC2A3, and GCH1), risk factors for prognosis of ESCA patients, were the basis for constructing the prognostic model. Validation of our model shows a meaningful capability for prognosis prediction. Furthermore, many biological functions and pathways related to immunity and ferroptosis were enriched in the high-risk group, and the role of the TMEM161B-AS1/hsa-miR-27a-3p/GCH1 network in ESCA is supported. Also, the KMT2D mutation is associated with our risk score and SLC2A3 expression. Overall, the prognostic model was associated with treatment sensitivity and levels of gene expression.

Conclusion: A novel, prognostic model was shown to have high predictive value. Biological processes related to immune functions, KMT2D mutation, CNV and the TMEM161B-AS1/hsa-miR-27a-3p/GCH1 network were involved in ESCA progression.

Identification and Validation of Constructing the Prognostic Model With Four DNA Methylation-Driven Genes in Pancreatic Cancer

Background: Pancreatic cancer (PC) is a highly aggressive gastrointestinal tumor and has a poor prognosis. Evaluating the prognosis validly is urgent for PC patients. In this study, we utilized the RNA-sequencing (RNA-seq) profiles and DNA methylation expression data comprehensively to develop and validate a prognostic signature in patients with PC.

Methods: The integrated analysis of RNA-seq, DNA methylation expression profiles, and relevant clinical information was performed to select four DNA methylation-driven genes. Then, a prognostic signature was established by the univariate, multivariate Cox, and least absolute shrinkage and selection operator (LASSO) regression analyses in The Cancer Genome Atlas (TCGA) dataset. GSE62452 cohort was utilized for external validation. Finally, a nomogram model was set up and evaluated by calibration curves.

Results: Nine DNA methylation-driven genes that were related to overall survival (OS) were identified. After multivariate Cox and LASSO regression analyses, four of these genes (RIC3, MBOAT2, SEZ6L, and OAS2) were selected to establish the predictive signature. The PC patients were stratified into two groups according to the median risk score, of which the low-risk group displayed a prominently favorable OS compared with the high-risk group, whether in the training (p < 0.001) or validation (p < 0.01) cohort. Then, the univariate and multivariate Cox regression analyses showed that age, grade, risk score, and the number of positive lymph nodes were significantly associated with OS in PC patients. Therefore, we used these clinical variables to construct a nomogram; and its performance in predicting the 1-, 2-, and 3-year OS of patients with PC was assessed via calibration curves.

Conclusion: A prognostic risk score signature was built with the four alternative DNA methylation-driven genes. Furthermore, in combination with the risk score, age, grade, and the number of positive lymph nodes, a nomogram was established for conveniently predicting the individualized prognosis of PC patients.

Clinical Utility of Epigenetic Changes in Pancreatic Adenocarcinoma

Pancreatic cancer is a molecularly heterogeneous disease. Epigenetic changes and epigenetic regulatory mechanisms underlie at least some of this heterogeneity and contribute to the evolution of aggressive tumor biology in patients and the tumor's intrinsic resistance to therapy. Here we review our current understanding of epigenetic dysregulation in pancreatic cancer and how it is contributing to our efforts in early diagnosis, predictive and prognostic biomarker development and new therapeutic approaches in this deadly cancer.

Epigenetic and metabolic interplay in cutaneous squamous cell carcinoma

With the ageing of the population and increased levels of recreational sun exposure and immunosuppression, cutaneous squamous cell carcinoma (cSCC), is both an enormous and expanding clinical and economic issue. Despite advances in therapy, up to 5000-8000 people are estimated to die every year from cSCC in the U.S., highlighting the need for both better prevention and treatments. Two emerging areas of scientific discovery that may offer new therapeutic approaches for cSCC are epigenetics and metabolism. Importantly, these disciplines display extensive crosstalk, with metabolic inputs contributing to the chromatin landscape, while the dynamic epigenome shapes transcriptional and cellular responses that feedback into cellular metabolism. Recent evidence suggests that indeed, epigenetic and metabolic dysregulation may be critical contributors to cSCC pathogenesis. Here, we synthesize the latest findings from these fast-moving fields, including how they may drive cSCC, yet also be harnessed for therapy.

Cancer-epigenetic function of the histone methyltransferase KMT2D and therapeutic opportunities for the treatment of KMT2D-deficient tumors

Epigenetic mechanisms are central to understanding the molecular basis underlying tumorigenesis. Aberrations in epigenetic modifiers alter epigenomic landscapes and play a critical role in tumorigenesis. Notably, the histone lysine methyltransferase KMT2D (a COMPASS/ Set1 family member; also known as MLL4, ALR, and MLL2) is among the most frequently mutated genes in many different types of cancer. Recent studies have demonstrated how KMT2D loss induces abnormal epigenomic reprograming and rewires molecular pathways during tumorigenesis. These findings also have clinical and therapeutic implications for cancer treatment. In this review, we summarize recent advances in understanding the role of KMT2D in regulating tumorigenesis and discuss therapeutic opportunities for the treatment of KMT2D-deficient tumors.

LncRNA MIR17HG promotes colorectal cancer liver metastasis by mediating a glycolysis-associated positive feedback circuit

Glycolysis plays a crucial role in reprogramming the metastatic tumor microenvironment. A series of lncRNAs have been identified to function as oncogenic molecules by regulating glycolysis. However, the roles of glycolysis-related lncRNAs in regulating colorectal cancer liver metastasis (CRLM) remain poorly understood. In the present study, the expression of the glycolysis-related lncRNA MIR17HG gradually increased from adjacent normal to CRC to the paired liver metastatic tissues, and high MIR17HG expression predicted poor survival, especially in patients with liver metastasis. Functionally, MIR17HG promoted glycolysis in CRC cells and enhanced their invasion and liver metastasis in vitro and in vivo. Mechanistically, MIR17HG functioned as a ceRNA to regulate HK1 expression by sponging miR-138-5p, resulting in glycolysis in CRC cells and leading to their invasion and liver metastasis. More interestingly, lactate accumulated via glycolysis activated the p38/Elk-1 signaling pathway to promote the transcriptional expression of MIR17HG in CRC cells, forming a positive feedback loop, which eventually resulted in persistent glycolysis and the invasion and liver metastasis of CRC cells. In conclusion, the present study indicates that the lactate-responsive lncRNA MIR17HG, acting as a ceRNA, promotes CRLM through a glycolysis-mediated positive feedback circuit and might be a novel biomarker and therapeutic target for CRLM.

MUC4 is a novel mediator in H. pylori infection-related pancreatic cancer

Pancreatic cancer (PC) is a common malignant disease worldwide. Among the potential pathogenic factors, Helicobacter pylori (H. pylori) infection has been associated with the tumorigenesis of PC. The present study aimed to identify the differentially expressed genes (DEGs) of H. pylori infection-associated PC and to investigate the key factors involved in PC tumorigenesis. Using bioinformatics methods, overlapping DEGs and key gene were identified from H. pylori-infected gastric mucosa (GM) and H. pylori infection-associated PC. Survival and tumor stage analyses were performed to assess the clinical associations. In addition, mucin 4 (MUC4) mRNA expression levels were measured in patient blood and tumor samples. According to the correlation analyses of four genes co-expressed, potential biological processes were identified. MUC4 was identified to be associated with H. pylori infection, and its levels were significantly upregulated in PC samples compared with those in normal samples in TCGA dataset, the PC cell line and patient tissue samples. H. pylori infection was also associated with MUC4 expression in patients' blood and tissue samples. In conclusion, the results of the present study revealed a potentially pathogenic role of MUC4 in H. pylori infection-associated PC. Thus, the tumorigenesis and metastasis of PC may be prevented by treating the H. pylori infection or using MUC4 antagonists.

A Highlight of the Mechanisms of Immune Checkpoint Blocker Resistance

In recent years, as our understanding of tumor immunology is continuously improved, immunotherapy has come to the center stage of cancer therapy and is deemed as the most promising approach for cancer control. Although immunotherapy, particularly immune checkpoint blockade (ICB), has achieved a milestone in several types of tumors, the majority of cancer patients do not benefit from immunotherapy. The dismal outcome of cancer immunotherapy is mainly due to primary or acquired resistance arising from tumor immune evasion. Exploring the mechanisms of tumor immune evasion in the course of immunotherapy may identify biological targets to conquer tumor resistance to immunotherapy. In this review, we highlight tumor cell-intrinsic and -extrinsic factors that may underlie tumor resistance to immune checkpoint blockers. Targeting these factors in combination with immune checkpoint blockers points to the future direction of cancer immunotherapy.

The Bidirectional Relationship Between Cancer Epigenetics and Metabolism

Metabolic and epigenetic reprogramming are characteristics of cancer cells that, in many cases, are linked. Oncogenic signaling, diet, and tumor microenvironment each influence the availability of metabolites that are substrates or inhibitors of epigenetic enzymes. Reciprocally, altered expression or activity of chromatin-modifying enzymes can exert direct and indirect effects on cellular metabolism. In this article, we discuss the bidirectional relationship between epigenetics and metabolism in cancer. First, we focus on epigenetic control of metabolism, highlighting evidence that alterations in histone modifications, chromatin remodeling, or the enhancer landscape can drive metabolic features that support growth and proliferation. We then discuss metabolic regulation of chromatin-modifying enzymes and roles in tumor growth and progression. Throughout, we highlight proposed therapeutic and dietary interventions that leverage metabolic-epigenetic cross talk and have the potential to improve cancer therapy.

Enhancer Reprogramming Confers Dependence on Glycolysis and IGF Signaling in KMT2D Mutant Melanoma

Histone methyltransferase KMT2D harbors frequent loss-of-function somatic point mutations in several tumor types, including melanoma. Here, we identify KMT2D as a potent tumor suppressor in melanoma through an in vivo epigenome-focused pooled RNAi screen and confirm the finding by using a genetically engineered mouse model (GEMM) based on conditional and melanocyte-specific deletion of KMT2D. KMT2D-deficient tumors show substantial reprogramming of key metabolic pathways, including glycolysis. KMT2D deficiency aberrantly upregulates glycolysis enzymes, intermediate metabolites, and glucose consumption rates. Mechanistically, KMT2D loss causes genome-wide reduction of H3K4me1-marked active enhancer chromatin states. Enhancer loss and subsequent repression of IGFBP5 activates IGF1R-AKT to increase glycolysis in KMT2D-deficient cells. Pharmacological inhibition of glycolysis and insulin growth factor (IGF) signaling reduce proliferation and tumorigenesis preferentially in KMT2D-deficient cells. We conclude that KMT2D loss promotes tumorigenesis by facilitating an increased use of the glycolysis pathway for enhanced biomass needs via enhancer reprogramming, thus presenting an opportunity for therapeutic intervention through glycolysis or IGF pathway inhibitors.

The role of histone methylation in the development of digestive cancers: a potential direction for cancer management

Digestive cancers are the leading cause of cancer-related death worldwide and have high risks of morbidity and mortality. Histone methylation, which is mediated mainly by lysine methyltransferases, lysine demethylases, and protein arginine methyltransferases, has emerged as an essential mechanism regulating pathological processes in digestive cancers. Under certain conditions, aberrant expression of these modifiers leads to abnormal histone methylation or demethylation in the corresponding cancer-related genes, which contributes to different processes and phenotypes, such as carcinogenesis, proliferation, metabolic reprogramming, epithelial–mesenchymal transition, invasion, and migration, during digestive cancer development. In this review, we focus on the association between histone methylation regulation and the development of digestive cancers, including gastric cancer, liver cancer, pancreatic cancer, and colorectal cancer, as well as on its clinical application prospects, aiming to provide a new perspective on the management of digestive cancers.

SETDB1 Inhibits p53-Mediated Apoptosis and Is Required for Formation of Pancreatic Ductal Adenocarcinomas in Mice

BACKGROUND & AIMS

SETDB1, a histone methyltransferase that trimethylates histone H3 on lysine 9, promotes development of several tumor types. We investigated whether SETDB1 contributes to development of pancreatic ductal adenocarcinoma (PDAC).

METHODS

We performed studies with Ptf1a^Cre; Kras^G12D; Setdb1^f/f, Ptf1a^Cre; Kras^G12D; Trp53^f/+; Setdb1^f/f, and Ptf1a^Cre; Kras^G12D; Trp53^f/f; Setdb1^f/f mice to investigate the effects of disruption of Setdb1 in mice with activated KRAS-induced pancreatic tumorigenesis, with heterozygous or homozygous disruption of Trp53. We performed microarray analyses of whole-pancreas tissues from Ptf1a^Cre; Kras^G12D; Setdb1^f/f, and Ptf1a^Cre; Kras^G12D mice and compared their gene expression patterns. Chromatin immunoprecipitation assays were performed using acinar cells isolated from pancreata with and without disruption of Setdb1. We used human PDAC cells for SETDB1 knockdown and inhibitor experiments.

RESULTS

Loss of SETDB1 from pancreas accelerated formation of premalignant lesions in mice with pancreata that express activated KRAS. Microarray analysis revealed up-regulated expression of genes in the apoptotic pathway and genes regulated by p53 in SETDB1-deficient pancreata. Deletion of Setdb1 from pancreas prevented formation of PDACs, concomitant with increased apoptosis and up-regulated expression of Trp53 in mice heterozygous for disruption of Trp53. In contrast, pancreata of mice with homozygous disruption of Trp53 had no increased apoptosis, and PDACs developed. Chromatin immunoprecipitation revealed that SETDB1 bound to the Trp53 promoter to regulate its expression. Expression of an inactivated form of SETDB1 in human PDAC cells with wild-type TP53 resulted in TP53-induced apoptosis.

CONCLUSIONS

We found that the histone methyltransferase SETDB1 is required for development of PDACs, induced by activated KRAS, in mice. SETDB1 inhibits apoptosis by regulating expression of p53. SETDB1 might be a therapeutic target for PDACs that retain p53 function.

Loss of Function of the Gene Encoding the Histone Methyltransferase KMT2D Leads to Deregulation of Mitochondrial Respiration

KMT2D encodes a methyltransferase responsible for histone 3 lysine 4 (H3K4) mono-/di-methylation, an epigenetic mark correlated with active transcription. Here, we tested the hypothesis that KMT2D pathogenic loss-of-function variants, which causes the Kabuki syndrome type 1, could affect the mitochondrial metabolic profile. By using Seahorse technology, we showed a significant reduction of the mitochondrial oxygen consumption rate as well as a reduction of the glycolytic flux in both Kmt2d knockout MEFs and skin fibroblasts of Kabuki patients harboring heterozygous KMT2D pathogenic variants. Mass-spectrometry analysis of intermediate metabolites confirmed alterations in the glycolytic and TCA cycle pathways. The observed metabolic phenotype was accompanied by a significant increase in the production of reactive oxygen species. Measurements of the specific activities of the mitochondrial respiratory chain complexes revealed significant inhibition of CI (NADH dehydrogenase) and CIV (cytochrome c oxidase); this result was further supported by a decrease in the protein content of both complexes. Finally, we unveiled an impaired oxidation of glucose and larger reliance on long-chain fatty acids oxidation. Altogether, our findings clearly indicate a rewiring of the mitochondrial metabolic phenotype in the KMT2D-null or loss-of-function context that might contribute to the development of Kabuki disease, and represents metabolic reprogramming as a potential new therapeutic approach.

Ectopic HOTTIP expression induces noncanonical transactivation pathways to promote growth and invasiveness in pancreatic ductal adenocarcinoma

HOXA transcript at the distal tip (HOTTIP), a long noncoding RNA, is upregulated in pancreatic ductal adenocarcinoma (PDAC), but the HOTTIP-mediated oncogenic pathway is not fully understood. We identified canonical HOTTIP-HOXA13 targets, CYP26B1, CLIC5, CHI3L1 and UCP2-responsible for cell growth and cell invasion. Genome-wide analysis revealed that 38% of HOTTIP-regulated genes contain H3K4me3 and HOTTIP enrichment at their promoters, without HOXA13 binding. HOTTIP complexes with WDR5-MLL1 to trans-activate oncogenic proteins CYB5R2, SULT1A1, KIF26A, SLC1A4, and TSC22D1 by directly inducing H3K4me3 at their promoters. The WDR5, MLL1, and H3K4me3 levels at their promoters and their expression levels are sensitive to HOTTIP expression. These results indicate the importance of the noncanonical trans-acting HOTTIP-WDR5-MLL1 pathway in the HOTTIP regulatory mechanism by promoting oncogenic protein expression. Furthermore, HOTTIP is regulated by miR-497 in PDAC cells, but HOTTIP is negatively correlated with miR-497 levels in PDAC tissues. In conclusion, HOTTIP is upregulated in PDAC due to the loss of the inhibitory miR-497; HOTTIP promotes PDAC progression through the canonical HOTTIP-HOXA13 axis. A novel noncanonical trans-acting HOTTIP-WDR5-MLL1-H3K4me3 pathway is also delineated.

KMT2D Deficiency Impairs Super-Enhancers to Confer a Glycolytic Vulnerability in Lung Cancer

Epigenetic modifiers frequently harbor loss-of-function mutations in lung cancer, but their tumor-suppressive roles are poorly characterized. Histone methyltransferase KMT2D (a COMPASS-like enzyme, also called MLL4) is among the most highly inactivated epigenetic modifiers in lung cancer. Here, we show that lung-specific loss of Kmt2d promotes lung tumorigenesis in mice and upregulates pro-tumorigenic programs, including glycolysis. Pharmacological inhibition of glycolysis preferentially impedes tumorigenicity of human lung cancer cells bearing KMT2D-inactivating mutations. Mechanistically, Kmt2d loss widely impairs epigenomic signals for super-enhancers/enhancers, including the super-enhancer for the circadian rhythm repressor Per2. Loss of Kmt2d decreases expression of PER2, which regulates multiple glycolytic genes. These findings indicate that KMT2D is a lung tumor suppressor and that KMT2D deficiency confers a therapeutic vulnerability to glycolytic inhibitors.

Sangivamycin and its derivatives inhibit Haspin-Histone H3-survivin signaling and induce pancreatic cancer cell death

Current treatment options for patients with pancreatic cancer are suboptimal, resulting in a five year survival rate of about 9%. Difficulties with treatment are due to an immunosuppressive, fibrotic tumor microenvironment that prevents drugs from reaching tumor cells, but also to the limited efficacy of existing FDA-approved chemotherapeutic compounds. We here show that the nucleoside analog Sangivamycin and its closely-related compound Toyocamycin target PDA cell lines, and are significantly more efficient than Gemcitabine. Using KINOMEscan screening, we identified the kinase Haspin, which is overexpressed in PDA cell lines and human PDA samples, as a main target for both compounds. Inhibition of Haspin leads to a decrease in Histone H3 phosphorylation and prevents Histone H3 binding to survivin, thus providing mechanistic insight of how Sangivamycin targets cell proliferation, mitosis and induces apoptotic cell death. In orthotopically implanted tumors in mice, Sangivamycin was efficient in decreasing the growth of established tumors. In summary, we show that Sangivamycin and derivatives can be an efficient new option for treatment of PDA.

MiRNA-217 accelerates the proliferation and migration of bladder cancer via inhibiting KMT2D

To uncover the biological function of miRNA-217 in the progression of bladder cancer and the underlying mechanism. Potential miRNAs binding KMT2D were predicted through online bioinformatics. Their expression levels in bladder cancer tissues and adjacent ones were determined. Through Pearson correlation analysis and survival analysis, the most potential miRNA candidate (miRNA-217) that targets and regulates KMT2D in bladder cancer was selected. Subsequently, expression levels of miRNA-217 and KMT2D in non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC) were detected. MiRNA-217 level in bladder cancer cell lines was determined as well. The interaction between KMT2D and miRNA-217 was verified by dual-luciferase reporter gene assay. Finally, regulatory effect of miRNA-217 on viability and migration in T24 and UMUC-3 cells were investigated. Five potential candidates that were upstream genes binding KMT2D were searched by bioinformatics. Among them, miRNA-217 was remarkably upregulated in bladder cancer tissues and closely linked to poor prognosis of affected patients. Moreover, dual-luciferase reporter gene assay verified the interaction between miRNA-217 and KMT2D. MiRNA-217 was able to downregulate mRNA and protein levels of KMT2D. Furthermore, knockdown of miRNA-217 attenuated viability and migration in bladder cancer cells. MiRNA-217 accelerates proliferative and migratory abilities in bladder cancer via inhibiting the level of tumor suppressor KMT2D, thereafter leading to the poor prognosis in bladder cancer patients.

KMT2D deficiency enhances the anti-cancer activity of L48H37 in pancreatic ductal adenocarcinoma

BACKGROUND

Novel therapeutic strategies are urgently needed for patients with a delayed diagnosis of pancreatic ductal adenocarcinoma (PDAC) in order to improve their chances of survival. Recent studies have shown potent anti-neoplastic effects of curcumin and its analogues. In addition, the role of histone methyltransferases on cancer therapeutics has also been elucidated. However, the relationship between these two factors in the treatment of pancreatic cancer remains unknown. Our working hypothesis was that L48H37, a novel curcumin analog, has better efficacy in pancreatic cancer cell growth inhibition in the absence of histone-lysine N-methyltransferase 2D (KMT2D).

AIM

To determine the anti-cancer effects of L48H37 in PDAC, and the role of KMT2D on its therapeutic efficacy.

METHODS

The viability and proliferation of primary (PANC-1 and MIA PaCa-2) and metastatic (SW1990 and ASPC-1) PDAC cell lines treated with L48H37 was determined by CCK8 and colony formation assay. Apoptosis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) levels, and cell cycle profile were determined by staining the cells with Annexin-V/7-AAD, JC-1, DCFH-DA, and PI respectively, as well as flow cytometric acquisition. In vitro migration was assessed by the wound healing assay. The protein and mRNA levels of relevant factors were analyzed using Western blotting, immunofluorescence and real time-quantitative PCR. The in situ expression of KMT2D in both human PDAC and paired adjacent normal tissues was determined by immunohistochemistry. In vivo tumor xenografts were established by injecting nude mice with PDAC cells. Bioinformatics analyses were also conducted using gene expression databases and TCGA.

RESULTS

L48H37 inhibited the proliferation and induced apoptosis in SW1990 and ASPC-1 cells in a dose- and time-dependent manner, while also reducing MMP, increasing ROS levels, arresting cell cycle at the G2/M stages and activating the endoplasmic reticulum (ER) stress-associated protein kinase RNA-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/activating transcription factor 4 (ATF4)/CHOP signaling pathway. Knocking down ATF4 significantly upregulated KMT2D in PDAC cells, and also decreased L48H37-induced apoptosis. Furthermore, silencing KMT2D in L48H37-treated cells significantly augmented apoptosis and the ER stress pathway, indicating that KMT2D depletion is essential for the anti-neoplastic effects of L48H37. Administering L48H37 to mice bearing tumors derived from control or KMT2D-knockdown PDAC cells significantly decreased the tumor burden. We also identified several differentially expressed genes in PDAC cell lines expressing very low levels of KMT2D that were functionally categorized into the extrinsic apoptotic signaling pathway. The KMT2D high- and low-expressing PDAC patients from the TCGA database showed similar survival rates,but higher KMT2D expression was associated with poor tumor grade in clinical and pathological analyses.

CONCLUSION

L48H37 exerts a potent anti-cancer effect in PDAC, which is augmented by KMT2D deficiency.

Alteration of Epigenetic Modifiers in Pancreatic Cancer and Its Clinical Implication

The incidence of pancreatic cancer has considerably increased in the past decade. Pancreatic cancer has the worst prognosis among the cancers of the digestive tract because the pancreas is located in the posterior abdominal cavity, and most patients do not show clinical symptoms for early detection. Approximately 55% of all patients are diagnosed with pancreatic cancer only after the tumors metastasize. Therefore, identifying useful biomarkers for early diagnosis and screening high-risk groups are important to improve pancreatic cancer therapy. Recent emerging evidence has suggested that genetic and epigenetic alterations play a crucial role in the molecular aspects of pancreatic tumorigenesis. Here, we summarize recent progress in our understanding of the epigenetic alterations in pancreatic cancer and propose potential synthetic lethal strategies to target these genetic defects to treat this deadly disease.

Pathogenic and Therapeutic Role of H3K4 Family of Methylases and Demethylases in Cancers

Histone modifications occupy an essential position in the epigenetic landscape of the cell, and their alterations have been linked to cancers. Histone 3 lysine 4 (H3K4) methylation has emerged as a critical epigenetic cue for the regulation of gene transcription through dynamic modulation by several H3K4 methyltransferases (writers) and demethylases (erasers). Any disturbance in the delicate balance of writers and erasers can result in the mis-regulation of H3K4 methylation, which has been demonstrated in several human cancers. Therefore, H3K4 methylation has been recognized as a putative therapeutic or prognostic tool and drug trials of different inhibitors of this process have demonstrated promising results. Henceforth, more detailed knowledge of H3K4 methylation is utmost important for elucidating the complex cellular processes, which might help in improving the disease outcome. The primary focus of this review will be directed on deciphering the role of H3K4 methylation along with its writers/erasers in different cancers.