On the potential role of DNMT1 in acute myeloid leukemia and myelodysplastic syndromes: not another mutated epigenetic driver

Bisphenol a: Epigenetic effects on the male reproductive system and male offspring

Bisphenol A (BPA) is a commonly used organic compound. Over the past decades, many studies have examined the mechanisms of BPA toxicity, with BPA-induced alterations in epigenetic modifications receiving considerable attention. Particularly in the male reproductive system, abnormal alterations in epigenetic markers can adversely affect reproductive function. Furthermore, these changes in epigenetic markers can be transmitted to offspring through the father. Here, we review the effects of BPA exposure on various epigenetic markers in the male reproductive system, including DNA methylation, histone modifications, and noncoding RNA, as well as associated changes in the male reproductive function. We also reviewed the effects of father's exposure to BPA on offspring epigenetic modification patterns.

CSRP1 gene: a potential novel prognostic marker in acute myeloid leukemia with implications for immune response

BACKGROUND

Acute myeloid leukemia, constituting a majority of leukemias, grapples with a 24% 5-year survival rate. Recent strides in research have unveiled fresh targets for drug therapies. LIM-only, a pivotal transcription factor within LIM proteins, oversees cell development and is implicated in tumor formation. Among these critical LIM proteins, CSRP1, a Cysteine-rich protein, emerges as a significant player in various diseases. Despite its recognition as a potential prognostic factor and therapeutic target in various cancers, the specific link between CSRP1 and acute myeloid leukemia remains unexplored. Our previous work, identifying CSRP1 in a prognostic model for AML patients, instigates a dedicated exploration into the nuanced role of CSRP1 in acute myeloid leukemia.

METHODS

R tool was conducted to analyze the public data. qPCR was applied to evaluate the expression of CSRP1 mRNA for clinical samples and cell line. Unpaired t test, Wilcoxon Rank Sum test, KM curves, spearman correlation test and Pearson correlation test were included in this study.

RESULTS

CSRP1 displays notable expression variations between normal and tumor samples in acute myeloid leukemia (AML). It stands out as an independent prognostic factor for AML patients, showing correlations with clinical factors like age and cytogenetics risk. Additionally, CSRP1 correlates with immune-related pathways, immune cells, and immune checkpoints in AML. Furthermore, the alteration of CSRP1 mRNA levels is observed upon treatment with a DNMT1 inhibitor for THP1 cells.

CONCLUSION

The CSRP1 has potential as a novel prognostic factor and appears to influence the immune response in acute myeloid leukemia. Additionally, there is an observed association between CSRP1 and DNA methylation in acute myeloid leukemia.

Emerging DNA Methylome Targets in FLT3-ITD-Positive Acute Myeloid Leukemia: Combination Therapy with Clinically Approved FLT3 Inhibitors

OPINION STATEMENT

The internal tandem duplication (ITD) mutation of the FMS-like receptor tyrosine kinase 3 (FLT3-ITD) is the most common mutation observed in approximately 30% of acute myeloid leukemia (AML) patients. It represents poor prognosis due to continuous activation of downstream growth-promoting signaling pathways such as STAT5 and PI3K/AKT. Hence, FLT3 is considered an attractive druggable target; selective small FLT3 inhibitors (FLT3Is), such as midostaurin and quizartinib, have been clinically approved. However, patients possess generally poor remission rates and acquired resistance when FLT3I used alone. Various factors in patients could cause these adverse effects including altered epigenetic regulation, causing mainly abnormal gene expression patterns. Epigenetic modifications are required for hematopoietic stem cell (HSC) self-renewal and differentiation; however, critical driver mutations have been identified in genes controlling DNA methylation (such as DNMT3A, TET2, IDH1/2). These regulators cause leukemia pathogenesis and affect disease diagnosis and prognosis when they co-occur with FLT3-ITD mutation. Therefore, understanding the role of different epigenetic alterations in FLT3-ITD AML pathogenesis and how they modulate FLT3I's activity is important to rationalize combinational treatment approaches including FLT3Is and modulators of methylation regulators or pathways. Data from ongoing pre-clinical and clinical studies will further precisely define the potential use of epigenetic therapy together with FLT3Is especially after characterized patients' mutational status in terms of FLT3 and DNA methlome regulators.

5-Aza-dC promotes T-cell acute lymphoblastic leukemia cell invasion via downregulation of DNMT1 and upregulation of MMP-2 and MMP-9

5-Aza-2'-deoxycytidine (5-Aza-dC) is a demethylation agent known to deplete DNA methyltransferases (DNMTs) in leukemia cancer cells, and can restore the expression of their target genes in Jurkat cells. The goal of this study was to discern the potential effect of 5-Aza-dC on the invasion of T-ALL cells in acute lymphoblastic leukemia (ALL). The role of matrix metallopeptidase (MMP)-2, MMP-9, and DNMT1 in cell invasion was determined using loss- and gain-of-function investigations in Jurkat- and Sup-T1-R cells. A nude mouse model of ALL was established for further exploration of their roles in vivo. MMP-2 and MMP-9 exhibited high expression and low DNA methylation levels in 5-Aza-dC-resistant T-ALL cells. DNMT1 was poorly expressed in 5-Aza-dC-resistant T-ALL cells and exhibited decreased enrichment in the promoter region of MMP-2 and MMP-9. Silencing of MMP-2 and MMP-9 or DNMT1 overexpression reduced T-ALL cell invasion. After treatment of Sup-T1 cells with 5-Aza-dC, MMP-2 and MMP-9 presented with reduced DNA methylation levels but increased expression, and DNMT1 expression was identified to be suppressed. Further, in vivo assays revealed that DNMT1 alleviated T-ALL by reducing the expression of MMP-2 and MMP-9 in vivo. All in all, 5-Aza-dC activates MMP-2 and MMP-9 expression by reducing DNMT1-dependent DNA methylation levels and, hence, promotes the invasion of T-ALL cells.

Epialleles and epiallelic heterogeneity in hematological malignancies

DNA methylation has a well-established role in the pathogenesis, prognosis, and response to treatment in all the spectra of hematological malignancies. However, most of the data reported involve average DNA methylation observed in a sample. The emergence of bisulfite sequencing methods such as enhanced reduced representation that permit analyze adjacent CpGs led to exciting findings. Among these are the epialleles shift and the resulting epigenetic heterogeneity observed in leukemias and lymphomas. Epialleles seem to have an influential role as the cause of mutations that characterize leukemias, may stratify groups with different prognosis and response to treatment, and may be redistributed in the genome at different time points of the disease promoting activation of alternate transcriptional networks. Epiallelic shift may be responsible for the intratumor heterogeneity observed within the cells of the same tumor which increases with disease aggressiveness. It may also responsible for the interpatient heterogeneity explaining why blood cancers exhibit different behavior among different patients. Understanding better epiallelic conformation and the consequent chromatin conformational changes and the pathways that may be affected will permit deeper understanding of hematological malignancies pathogenesis and treatment.

Emerging Evidence of the Significance of Thioredoxin-1 in Hematopoietic Stem Cell Aging

The United States is undergoing a demographic shift towards an older population with profound economic, social, and healthcare implications. The number of Americans aged 65 and older will reach 80 million by 2040. The shift will be even more dramatic in the extremes of age, with a projected 400% increase in the population over 85 years old in the next two decades. Understanding the molecular and cellular mechanisms of ageing is crucial to reduce ageing-associated disease and to improve the quality of life for the elderly. In this review, we summarized the changes associated with the ageing of hematopoietic stem cells (HSCs) and what is known about some of the key underlying cellular and molecular pathways. We focus here on the effects of reactive oxygen species and the thioredoxin redox homeostasis system on ageing biology in HSCs and the HSC microenvironment. We present additional data from our lab demonstrating the key role of thioredoxin-1 in regulating HSC ageing.

Epigenetics-Associated Risk Reduction of Hematologic Neoplasms in a Nationwide Cohort Study: The Chemopreventive and Therapeutic Efficacy of Hydralazine

Background

Although several epigenetic drugs have been reported to have therapeutic efficacy for some hematologic neoplasms (HNs) in clinical trials, few achieved disease-free survival benefit. The traditional drug discovery pathway is costly and time-consuming, and thus, more effective strategies are required. We attempted to facilitate epigenetic drug repositioning for therapy of HNs by screening the Human Epigenetic Drug Database (HEDD) in the web, conducting a bench-work cytotoxicity test and a retrospective nationwide cohort study prior to a clinical trial.

Methods

Four FDA-approved epigenetic drugs with antitumor properties and completion of clinical phase II trials were selected from HEDD. Hydralazine (HDZ) and valproate (VAL) among the four were selected with higher cytotoxicity to HN cells, no matter whether carrying the JAK2V617F mutation or not. Both of them were chosen for a cohort study using the Longitudinal Health Insurance Database (LHID) 2000–2015 (N = 1,936,512), a subset of the National Health Insurance Research Database (NHIRD, N= 25.68 millions) in Taiwan.

Results

In the initial cohort, HDZ or VAL exposure subjects (11,049) and matching reference subjects (44,196) were enrolled according to maximal daily consumption (300/2,100 mg per day of HDZ/VAL). The HN incidence in HDZ and VAL exposure groups reduced from 4.97% to 3.90% (p <.001) and 4.45% (p = .075), respectively. A further cohort study on HDZ at a lower range of the WHO defined daily dose (<34 mg per day) and HN incidence of HDZ exposure subjects (75,612) reduced from 5.01% to 4.16% (p = 1.725 × 10 ^-18) compared to the reference subjects (302,448).

Conclusions

An association of a chronically prescribed HDZ, even prescribed low dose, with reduction of overall incidence rate and in most subgroups of HN was observed in our study. Repositioning HDZ for HN management may be feasible. This is the first nationwide cohort study of the epigenetics-associated risk evaluation of overall HN in the existing literature, showing an effective method with a wider scope to inform contemporary clinical trials of epigenetic drugs in the future.

Oncogenes and the Origins of Leukemias

Self-maintaining hematopoietic stem cells are a cell population that is primarily ‘at risk’ to malignant transformation, and the cell-of-origin for some leukemias. Tissue-specific stem cells replenish the different types of functional cells within a particular tissue to meet the demands of an organism. For hematopoietic stem cells, this flexibility is important to satisfy the changing requirements for a certain type of immune cell, when needed. From studies of the natural history of childhood acute lymphoblastic leukemia, an initial oncogenic and prenatal insult gives rise to a preleukemic clone. At least a second genomic insult is needed that gives rise to a leukemia stem cell: this cell generates a hierarchy of leukemia cells. For some leukemias, there is evidence to support the concept that one of the genomic insults leads to dysregulation of the tissue homeostatic role of hematopoietic stem cells so that the hierarchy of differentiating leukemia cells belongs to just one cell lineage. Restricting the expression of particular oncogenes in transgenic mice to hematopoietic stem and progenitor cells led to different human-like lineage-restricted leukemias. Lineage restriction is seen for human leukemias by virtue of their sub-grouping with regard to a phenotypic relationship to just one cell lineage.

Oncogenes, Proto-Oncogenes, and Lineage Restriction of Cancer Stem Cells

In principle, an oncogene is a cellular gene (proto-oncogene) that is dysfunctional, due to mutation and fusion with another gene or overexpression. Generally, oncogenes are viewed as deregulating cell proliferation or suppressing apoptosis in driving cancer. The cancer stem cell theory states that most, if not all, cancers are a hierarchy of cells that arises from a transformed tissue-specific stem cell. These normal counterparts generate various cell types of a tissue, which adds a new dimension to how oncogenes might lead to the anarchic behavior of cancer cells. It is that stem cells, such as hematopoietic stem cells, replenish mature cell types to meet the demands of an organism. Some oncogenes appear to deregulate this homeostatic process by restricting leukemia stem cells to a single cell lineage. This review examines whether cancer is a legacy of stem cells that lose their inherent versatility, the extent that proto-oncogenes play a role in cell lineage determination, and the role that epigenetic events play in regulating cell fate and tumorigenesis.

Hypomethylating Agents and Immunotherapy: Therapeutic Synergism in Acute Myeloid Leukemia and Myelodysplastic Syndromes

Decitabine and guadecitabine are hypomethylating agents (HMAs) that exert inhibitory effects against cancer cells. This includes stimulation of anti-tumor immunity in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) patients. Treatment of AML and MDS patients with the HMAs confers upregulation of cancer/testis antigens (CTAs) expression including the highly immunogenic CTA NY-ESO-1. This leads to activation of CD4⁺ and CD8⁺ T cells for elimination of cancer cells, and it establishes the feasibility to combine cancer vaccine with HMAs to enhance vaccine immunogenicity. Moreover, decitabine and guadecitabine induce the expression of immune checkpoint molecules in AML cells. In this review, the accumulating knowledge on the immunopotentiating properties of decitabine and guadecitabine in AML and MDS patients are presented and discussed. In summary, combination of decitabine or guadecitabine with NY-ESO-1 vaccine enhances vaccine immunogenicity in AML patients. T cells from AML patients stimulated with dendritic cell (DC)/AML fusion vaccine and guadecitabine display increased capacity to lyse AML cells. Moreover, decitabine enhances NK cell-mediated cytotoxicity or CD123-specific chimeric antigen receptor-engineered T cells antileukemic activities against AML. Furthermore, combination of either HMAs with immune checkpoint blockade (ICB) therapy may circumvent their resistance. Finally, clinical trials of either HMAs combined with cancer vaccines, NK cell infusion or ICB therapy in relapsed/refractory AML and high-risk MDS patients are currently underway, highlighting the promising efficacy of HMAs and immunotherapy synergy against these malignancies.

Epigenetic Regulators as the Gatekeepers of Hematopoiesis

Hematopoiesis is the process by which both fetal and adult organisms derive the full repertoire of blood cells from a single multipotent progenitor cell type, the hematopoietic stem cells (HSCs). Correct enactment of this process relies on a synergistic interplay between genetically encoded differentiation programs and a host of cell-intrinsic and cell-extrinsic factors. These include the influence of the HSC niche microenvironment, action of specific transcription factors, and alterations in intracellular metabolic state. The consolidation of these inputs with the genetically encoded program into a coherent differentiation program for each lineage is thought to rely on epigenetic modifiers. Recent work has delineated the precise contributions of different classes of epigenetic modifiers to HSC self-renewal as well as lineage specification and differentiation into various cell types. Here, we bring together what is currently known about chromatin status and the development of cells in the hematopoietic system under normal and abnormal conditions.

Advances in Therapeutic Targeting of Cancer Stem Cells within the Tumor Microenvironment: An Updated Review

Despite great strides being achieved in improving cancer patients' outcomes through better therapies and combinatorial treatment, several hurdles still remain due to therapy resistance, cancer recurrence and metastasis. Drug resistance culminating in relapse continues to be associated with fatal disease. The cancer stem cell theory posits that tumors are driven by specialized cancer cells called cancer stem cells (CSCs). CSCs are a subpopulation of cancer cells known to be resistant to therapy and cause metastasis. Whilst the debate on whether CSCs are the origins of the primary tumor rages on, CSCs have been further characterized in many cancers with data illustrating that CSCs display great abilities to self-renew, resist therapies due to enhanced epithelial to mesenchymal (EMT) properties, enhanced expression of ATP-binding cassette (ABC) membrane transporters, activation of several survival signaling pathways and increased immune evasion as well as DNA repair mechanisms. CSCs also display great heterogeneity with the consequential lack of specific CSC markers presenting a great challenge to their targeting. In this updated review we revisit CSCs within the tumor microenvironment (TME) and present novel treatment strategies targeting CSCs. These promising strategies include targeting CSCs-specific properties using small molecule inhibitors, immunotherapy, microRNA mediated inhibitors, epigenetic methods as well as targeting CSC niche-microenvironmental factors and differentiation. Lastly, we present recent clinical trials undertaken to try to turn the tide against cancer by targeting CSC-associated drug resistance and metastasis.

QSAR-driven rational design of novel DNA methyltransferase 1 inhibitors

DNA methylation, an epigenetic modification, is mediated by DNA methyltransferases (DNMTs), a family of enzymes. Inhibitions of these enzymes are considered a promising strategy for the treatment of several diseases. In this study, a quantitative structure-activity relationship (QSAR) modeling was employed to understand the structure-activity relationship (SAR) of currently available non-nucleoside DNMT1 inhibitors (i.e., indole and oxazoline/1,2-oxazole scaffolds). Two QSAR models were successfully constructed using multiple linear regression (MLR) and provided good predictive performance (R²_Tr = 0.850-0.988 and R²_CV = 0.672-0.869). Bond information content index (BIC1) and electronegativity (R6e+) are the most influential descriptors governing the activity of compounds. The constructed QSAR models were further applied for guiding a rational design of novel inhibitors. A novel set of 153 structurally modified compounds were designed in silico according to the important descriptors deduced from the QSAR finding, and their DNMT1 inhibitory activities were predicted. This result demonstrated that 86 newly designed inhibitors were predicted to elicit enhanced DNMT1 inhibitory activity when compared to their parent compounds. Finally, a set of promising compounds as potent DNMT1 inhibitors were highlighted to be further developed. The key SAR findings may also be beneficial for structural optimization to improve properties of the known inhibitors.

Methyltransferase DNMT3B in leukemia

DNA methyltransferases (DNMTs) are highly conserved DNA-modifying enzymes that play important roles in epigenetic regulation and they are involved in cell proliferation, differentiation, and apoptosis. In mammalian cells, three active DNMTs have been identified: DNMT1 acts as a maintenance methyltransferase to replicate preexisting methylation patterns, whereas DNMT3A and DNMT3B primarily act as de novo methyltransferases that are responsible for establishing DNA methylation patterns by adding a methyl group to cytosine bases. The expression of DNMT3B is widespread in a variety of hematological cells and it is altered in each type of leukemia, which is associated with its pathogenesis, progression, treatment, and prognosis. Here, we review current information on DNMT3B in leukemia, including its expression, single-nucleotide polymorphisms, mutations, regulation, function, and clinical value for anti-leukemic therapy and prognosis.

Protein expression trends of DNMT1 in gastrointestinal diseases: From benign to precancerous lesions to cancer

BACKGROUND

In recent years, the incidence of gastrointestinal (GI) cancer in China has increased annually. Early detection and appropriate therapy are considered to be the key to treat GI cancer. DNMT1 takes an active part in the advancement of GI cancer, which will change as the disease progresses. But its expression characteristics in the dynamic variations of GI carcinogenesis are still unclear.

AIM

To investigate the expression characteristics of DNMT1 in different GI diseases.

METHODS

We detected the expression of DNMT1 in 650 cases of different GI diseases by immunohistochemistry, including 90 cases of chronic superficial gastritis (CSG), 72 cases of atrophic gastritis with intestinal metaplasia (AG/GIM), 54 cases of low-grade intraepithelial neoplasia (GLIN), 66 cases of high-grade intraepithelial neoplasia (GHIN), 71 cases of early gastric cancer (EGC), 90 cases of normal intestinal mucosa (NIM), 54 cases of intestinal low-grade intraepithelial neoplasia (ILIN), 71 cases of intestinal high-grade intraepithelial neoplasia (IHIN), and 82 cases of early colorectal cancer (ECRC).

RESULTS

In the CSG group, all cases showed weakly positive or negative expression of DNMT1. However, in other four groups (AG/GIM, GLIN, GHIN, and EGC), the positive expression rate gradually increased with the severity of the diseases; the negative or weakly positive cases accounted for 55.56% (40/72), 38.89% (21/54), 1.52% (1/66), and 1.41% (1/71), respectively. Besides, the moderately positive cases were 44.44% (32/72), 57.41% (31/54), 80.30% (53/66), and 43.66% (31/71), respectively. The strongly positive cases only existed in the GLIN (3.70%, 2/54), GHIN (18.18%, 12/66), and EGC (54.93%, 39/71) groups. The differences between any two groups were statistically significant (P < 0.05). Similarly, in the NIM group, cases with weakly positive expression of DNMT1 were predominant (91.11%, 82/90), and the rest were moderately positive cases (8.89%, 8/90). In the ILIN, IHIN, and ECRC groups, the rates of cases with weak or negative expression of DNMT1 were 46.30% (25/54), 12.68% (9/71), and 4.88% (4/82), respectively; with moderately positive expression were 53.70% (29/54), 71.83% (51/71), and 34.15% (28/82), respectively; and with strongly positive expression were 0.00% (0/54), 15.49% (11/71), and 60.98% (50/82), respectively. The differences between any two groups were also statistically significant (P < 0.05).

CONCLUSION

The overexpression of DNMT1 protein could effectively predict early GI cancers and severe precancerous lesions, which may have potential clinical application value.

Lactate-fueled oxidative metabolism drives DNA methyltransferase 1-mediated transcriptional co-activator with PDZ binding domain protein activation

Activity of transcriptional co‐activator with PDZ binding domain (TAZ) protein is strongly implicated in the pathogenesis of human cancer and is influenced by tumor metabolism. High levels of lactate concentration in the tumor microenvironment as a result of metabolic reprogramming are inversely correlated with patient overall survival. Herein, we investigated the role of lactate in the regulation of the activity of TAZ and showed that glycolysis‐derived lactate efficiently increased TAZ expression and activity in lung cancer cells. We showed that the reactive oxygen species (ROS) generated by lactate‐fueled oxidative phosphorylation (OXPHOS) in mitochondria activated AKT and thereby inhibited glycogen synthase kinase 3 beta/beta‐transducin repeat‐containing proteins (GSK‐3β/β‐TrCP)‐mediated ubiquitination and degradation of DNA methyltransferase 1 (DNMT1). Upregulation of DNMT1 by lactate caused hypermethylation of TAZ negative regulator of the LATS2 gene promoter, leading to TAZ activation. Moreover, TAZ binds to the promoter of DNMT1 and is necessary for DNMT1 transcription. Our study showed a molecular mechanism of DNMT1 in linking tumor metabolic reprogramming to the Hippo‐TAZ pathway and functional significance of the DNMT1‐TAZ feedback loop in the migratory and invasive potential of lung cancer cells.

The repression and reciprocal interaction of DNA methyltransferase 1 and specificity protein 1 contributes to the inhibition of MET expression by the combination of Chinese herbal medicine FZKA decoction and erlotinib

ETHNOPHARMACOLOGICAL RELEVANCE

The Chinese herbal medicine Fuzheng Kang-Ai (FZKA) decoction obtained from Guangdong Kangmei Pharmaceutical Company, which contains 12 components with different types of constituents, has been used as part of the adjuvant treatment of lung cancer for decades. We previously showed that FZKA decoction enhances the growth inhibition of epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI)-resistant non-small cell lung cancer (NSCLC) cells by suppressing glycoprotein mucin 1 (MUC1) expression. However, the molecular mechanism underlying the therapeutic potential, particularly in sensitizing or/and enhancing the anti-lung cancer effect of EGFR-TKIs, remains unclear.

MATERIALS AND METHODS

Cell viability was measured using 3-(4, 5-diMEThylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and 5-ethynyl -2'-deoxyuridine (EdU) assays. Western blot analysis was performed to examine the protein expressions of DNA methyltransferase 1 (DNMT1), specificity protein 1 (SP1), and MET, an oncogene encoding for a trans-membrane tyrosine kinase receptor activated by the hepatocyte growth factor (HGF). The expression of MET mRNA was measured by quantitative real-time PCR (qRT-PCR). Exogenous expression of DNMT1 and SP1, and MET were carried out by transient transfection assays. The promoter activity of MET was tested using Dual-luciferase reporter assays. A nude mouse xenografted tumor model further evaluated the effect of the combination of FZKA decoction and erlotinib in vivo.

RESULTS

The combination of FZKA and erlotinib produced an even greater inhibition of NSCLC cell growth. FZKA decreased the expressions of DNMT1, SP1, and MET (c-MET) proteins, and the combination of FZKA and erlotinib demonstrated enhanced responses. Interestingly, there was a mutual regulation of DNMT1 and SP1. In addition, exogenously expressed DNMT1 and SP1 blocked the FZKA-inhibited c-MET expression. Moreover, excessive expressed MET neutralized FZKA-inhibited growth of NSCLC cells. FZKA decreased the mRNA and promoter activity of c-MET, which was not observed in cells with ectopic expressed DNMT1 gene. Similar findings were observed in vivo.

CONCLUSION

FZKA decreases MET gene expression through the repression and mutual regulation of DNMT1 and SP1 in vitro and in vivo. This leads to inhibit the growth of human lung cancer cells. The combination of FZKA and EGFR-TKI erlotinib exhibits synergy in this process. The regulatory loops among the DNMT1, SP1 and MET converge in the overall effects of FZKA and EGFR-TKI erlotinib. This in vitro and in vivo study clarifies an additional novel molecular mechanism underlying the anti-lung cancer effects in response to the combination of FZKA and erlotinib in gefitinib-resistant NSCLC cells.

Cell-specific proteome analyses of human bone marrow reveal molecular features of age-dependent functional decline

Diminishing potential to replace damaged tissues is a hallmark for ageing of somatic stem cells, but the mechanisms remain elusive. Here, we present proteome-wide atlases of age-associated alterations in human haematopoietic stem and progenitor cells (HPCs) and five other cell populations that constitute the bone marrow niche. For each, the abundance of a large fraction of the ~12,000 proteins identified is assessed in 59 human subjects from different ages. As the HPCs become older, pathways in central carbon metabolism exhibit features reminiscent of the Warburg effect, where glycolytic intermediates are rerouted towards anabolism. Simultaneously, altered abundance of early regulators of HPC differentiation reveals a reduced functionality and a bias towards myeloid differentiation. Ageing causes alterations in the bone marrow niche too, and diminishes the functionality of the pathways involved in HPC homing. The data represent a valuable resource for further analyses, and for validation of knowledge gained from animal models.

Ageing causes an inability to replace damaged tissue. Here, the authors perform proteomics analyses of human haematopoietic stem cells and other cells in the bone marrow niche at different ages and show changes in central carbon metabolism, reduced bone marrow niche function, and enhanced myeloid differentiation.

Enhancer DNA methylation in acute myeloid leukemia and myelodysplastic syndromes

DNA methylation (CpG methylation) exerts an important role in normal differentiation and proliferation of hematopoietic stem cells and their differentiated progeny, while it has also the ability to regulate myeloid versus lymphoid fate. Mutations of the epigenetic machinery are observed in hematological malignancies including acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) resulting in hyper- or hypo-methylation affecting several different pathways. Enhancers are cis-regulatory elements which promote transcription activation and are characterized by histone marks including H3K27ac and H3K4me1/2. These gene subunits are target gene expression 'fine-tuners', are differentially used during the hematopoietic differentiation, and, in contrast to promoters, are not shared by the different hematopoietic cell types. Although the interaction between gene promoters and DNA methylation has extensively been studied, much less is known about the interplay between enhancers and DNA methylation. In hematopoiesis, DNA methylation at enhancers has the potential to discriminate between fetal and adult erythropoiesis, and also is a regulatory mechanism in granulopoiesis through repression of neutrophil-specific enhancers in progenitor cells during maturation. The interplay between DNA methylation at enhancers is disrupted in AML and MDS and mainly hyper-methylation at enhancers raising early during myeloid lineage commitment is acquired during malignant transformation. Interactions between mutated epigenetic drivers and other oncogenic mutations also affect enhancers' activity with final result, myeloid differentiation block. In this review, we have assembled recent data regarding DNA methylation and enhancers' activity in normal and mainly myeloid malignancies.

Homocysteine-induced proliferation of vascular smooth muscle cells occurs via PTEN hypermethylation and is mitigated by Resveratrol

Vascular smooth muscle cell (VSMC) proliferation is a primary pathological event in the development of atherosclerosis (AS), and the presence of homocysteine (Hcy) acts as an independent risk factor for AS. However, the underlying mechanisms remain to be elucidated. Phosphatase and tensin homologue on chromosome 10 (PTEN), is endogenously expressed in VSMCs and induces multiple signaling networks involved in cell proliferation, survival and inflammation, however, the specific role of PTEN is still unknown. The present study detected the proliferation ratio of VSMCs following treatment with Hcy and Resveratrol (RSV). In the 100 µM Hcy group, the proliferation ratio increased, and treatment with RSV decreased the proliferation ratio induced by Hcy. Reverse transcription‑quantitative polymerase chain reaction and western blotting were used to analyze PTEN expression, RSV treatment was associated with decreased PTEN expression levels in VSMCs. PTEN levels were decreased in Hcy treated cells, and the proliferation ratio of VSMCs were increased following treated with Hcy. To study the mechanism of regulation of PTEN by Hcy, the present study detected PTEN methylation levels in VSMCs, and PTEN DNA methylation levels were demonstrated to be increased in the 100 µM Hcy group, whereas treatment with RSV decreased the methylation status. DNA methyltransferase 1 is important role in the regulation of PTEN methylation. Overall, Hcy impacts the methylation status of PTEN, which is involved in cell proliferation, and induces the proliferation of VSMCs. This effect is alleviated by treatment with RSV, which exhibits an antagonistic mechanism against Hcy.

DNMT1 overexpression predicting gastric carcinogenesis, subsequent progression and prognosis: a meta and bioinformatic analysis

DNMT1 is important in maintaining DNA methylation, and participates in the oncogenesis via up- or down-regulation leading to hyper-methylation or hypo-methylation. In the meta and bioinformatic analysis, we found that DNMT1 expression was higher in gastric cancer, compared with normal (p < 0.00001), para-cancerous (p = 0.0004) and dysplasia (p < 0.00001) tissues. DNMT1 up-regulation was associated with gender (OR = 2.27, p = 0.006), differentiation (OR = 0.21, p = 0.01) and TNM stage (OR = 0.31, p = 0.0005). Through TCGA database, DNMT1 overexpression increased gastric cancer risk, but unrelated with clinicopathological parameters and prognosis. Kaplan-Meier plotter showed, an increasing expression of DNMT1 was positive for overall survival rates of patients with stage III and IV (P = 0.044; P = 0.047), N2 and N1-3 phases of lymph node metastasis (P = 0.023; P = 0.032), as well as those with or without distant metastasis (P = 0.0052; P = 0.021). For DNMT1 negative patients, the progression-free survival rates was better in patients with Her2+ or Her2- than positive ones (P = 0.00015; P = 0.031). Besides, surgery alone was effective for the overall survival rates in patients with DNMT1 high expression (P = 0.035), while 5-Fu was useful for those with low expression (P < 0.05). In conclusion, these findings provided evidence that DNMT1 expression might be employed as a potential marker to indicate gastric carcinogenesis and subsequent progression, even prognosis.

Using zebrafish models of leukemia to streamline drug screening and discovery

Current treatment strategies for acute leukemias largely rely on nonspecific cytotoxic drugs that result in high therapy-related morbidity and mortality. Cost-effective, pertinent animal models are needed to link in vitro studies with the development of new therapeutic agents in clinical trials on a high-throughput scale. However, targeted therapies have had limited success moving from bench to clinic, often due to unexpected off-target effects. The zebrafish has emerged as a reliable in vivo tool for modeling human leukemia. Zebrafish genetic and xenograft models of acute leukemia provide an unprecedented opportunity to conduct rapid, phenotype-based screens. This allows for the identification of relevant therapies while simultaneously evaluating drug toxicity, thus circumventing the limitations of target-centric approaches.