Deletion of MBD2 inhibits proliferation of chronic myeloid leukaemia blast phase cells

Methyl-CpG binding domain protein 2 (Mbd2) drives breast cancer progression through the modulation of epithelial-to-mesenchymal transition

Methyl-CpG-binding domain protein 2 (Mbd2), a reader of DNA methylation, has been implicated in different types of malignancies, including breast cancer. However, the exact role of Mbd2 in various stages of breast cancer growth and progression in vivo has not been determined. To test whether Mbd2 plays a causal role in mammary tumor growth and metastasis, we performed genetic knockout (KO) of Mbd2 in MMTV-PyMT transgenic mice and compared mammary tumor progression kinetics between the wild-type (PyMT-Mbd2+/+) and KO (PyMT-Mbd2-/-) groups. Our results demonstrated that deletion of Mbd2 in PyMT mice impedes primary tumor growth and lung metastasis at the experimental endpoint (postnatal week 20). Transcriptomic and proteomic analyses of primary tumors revealed that Mbd2 deletion abrogates the expression of several key determinants involved in epithelial-to-mesenchymal transition, such as neural cadherin (N-cadherin) and osteopontin. Importantly, loss of the Mbd2 gene impairs the activation of the PI3K/AKT pathway, which is required for PyMT-mediated oncogenic transformation, growth, and survival of breast tumor cells. Taken together, the results of this study provide a rationale for further development of epigenetic therapies targeting Mbd2 to inhibit the progression of breast cancer.

Increased Methyl-CpG-Binding Domain Protein 2 Promotes Cigarette Smoke-Induced Pulmonary Hypertension

Pulmonary hypertension (PH) is a chronic vascular proliferative disorder. While cigarette smoke (CS) plays a vital part in PH related to chronic obstructive pulmonary disease (COPD). Methyl-CpG-Binding Domain Protein 2 (MBD2) has been linked to multiple proliferative diseases. However, the specific mechanisms of MBD2 in CS-induced PH remain to be elucidated. Herein, the differential expression of MBD2 was tested between the controls and the PH patients’ pulmonary arteries, CS-exposed rat models’ pulmonary arteries, and primary human pulmonary artery smooth muscle cells (HPASMCs) following cigarette smoke extract (CSE) stimulation. As a result, PH patients and CS-induced rats and HPASMCs showed an increase in MBD2 protein expression compared with the controls. Then, MBD2 silencing was used to investigate the function of MBD2 on CSE-induced HPASMCs’ proliferation, migration, and cell cycle progression. As a consequence, CSE could induce HPASMCs’ increased proliferation and migration, and cell cycle transition, which were suppressed by MBD2 interference. Furthermore, RNA-seq, ChIP-qPCR, and MassARRAY were conducted to find out the downstream mechanisms of MBD2 for CS-induced pulmonary vascular remodeling. Subsequently, RNA-seq revealed MBD2 might affect the transcription of BMP2 gene, which furtherly altered the expression of BMP2 protein. ChIP-qPCR demonstrated MBD2 could bind BMP2’s promotor. MassARRAY indicated that MBD2 itself could not directly affect DNA methylation. In sum, our results indicate that increased MBD2 expression promotes CS-induced pulmonary vascular remodeling. The fundamental mechanisms may be that MBD2 can bind BMP2’s promoter and downregulate its expression. Thus, MBD2 may promote the occurrence of the CS-induced PH.

Genetic or siRNA inhibition of MBD2 attenuates the UUO- and I/R-induced renal fibrosis via downregulation of EGR1

DNA methylation plays a pivotal role in the progression of renal fibrosis. Methyl-CpG–binding domain protein 2 (MBD2), a protein reader of methylation, is involved in the development of acute kidney injury (AKI) caused by vancomycin. However, the role and mechanism of action of MBD2 in renal remain unclear. In this study, MBD2 mediated extracellular matrix (ECM) production induced by TGF-β1 in Boston University mouse proximal tubule (BUMPT) cells，and upregulated the expression EGR1 to promote ECM production in murine embryonic NIH 3T3 fibroblasts. ChIP analysis demonstrated that MBD2 physically interacted with the promoter region of the CpG islands of EGR1 genes and then activated their expression by inducing hypomethylation of the promoter region. In vivo, PT-MBD2-KO attenuated unilateral ureteral obstruction (UUO)-induced renal tubulointerstitial fibrosis via downregulation of EGR1, which was demonstrated by the downregulation of fibronectin (FN), collagen I and IV, α-SMA, and EGR1. Injection of MBD2-siRNA attenuated the UUO- and I/R-induced renal fibrosis. Those molecular changes were verified by biopsies from patients with obstructive nephropathy (OB). These data collectively demonstrated that inhibition of MBD2 reduces renal fibrosis via downregulating EGR1, which could be a target for treatment of fibrotic kidney disease.

LncRNAs and Rheumatoid Arthritis: From Identifying Mechanisms to Clinical Investigation

Rheumatoid arthritis (RA) is a systemic chronic autoinflammatory disease, and the synovial hyperplasia, pannus formation, articular cartilage damage and bone matrix destruction caused by immune system abnormalities are the main features of RA. The use of Disease Modifying Anti-Rheumatic Drugs (DMARDs) has achieved great advances in the therapy of RA. Yet there are still patients facing the problem of poor response to drug therapy or drug intolerance. Current therapy methods can only moderate RA progress, but cannot stop or reverse the damage it has caused. Recent studies have reported that there are a variety of long non-coding RNAs (LncRNAs) that have been implicated in mediating many aspects of RA. Understanding the mechanism of LncRNAs in RA is therefore critical for the development of new therapy strategies and prevention strategies. In this review, we systematically elucidate the biological roles and mechanisms of action of LncRNAs and their mechanisms of action in RA. Additionally, we also highlight the potential value of LncRNAs in the clinical diagnosis and therapy of RA.

Utilization of CRISPR-Mediated Tools for Studying Functional Genomics in Hematological Malignancies: An Overview on the Current Perspectives, Challenges, and Clinical Implications

Hematological malignancies (HM) are a group of neoplastic diseases that are usually heterogenous in nature due to the complex underlying genetic aberrations in which collaborating mutations enable cells to evade checkpoints that normally safeguard it against DNA damage and other disruptions of healthy cell growth. Research regarding chromosomal structural rearrangements and alterations, gene mutations, and functionality are currently being carried out to understand the genomics of these abnormalities. It is also becoming more evident that cross talk between the functional changes in transcription and proteins gives the characteristics of the disease although specific mutations may induce unique phenotypes. Functional genomics is vital in this aspect as it measures the complete genetic change in cancerous cells and seeks to integrate the dynamic changes in these networks to elucidate various cancer phenotypes. The advent of CRISPR technology has indeed provided a superfluity of benefits to mankind, as this versatile technology enables DNA editing in the genome. The CRISPR-Cas9 system is a precise genome editing tool, and it has revolutionized methodologies in the field of hematology. Currently, there are various CRISPR systems that are used to perform robust site-specific gene editing to study HM. Furthermore, experimental approaches that are based on CRISPR technology have created promising tools for developing effective hematological therapeutics. Therefore, this review will focus on diverse applications of CRISPR-based gene-editing tools in HM and its potential future trajectory. Collectively, this review will demonstrate the key roles of different CRISPR systems that are being used in HM, and the literature will be a representation of a critical step toward further understanding the biology of HM and the development of potential therapeutic approaches.

Loss of MBD2 attenuates MLL-AF9-driven leukemogenesis by suppressing the leukemic cell cycle via CDKN1C

Acute myeloid leukemia (AML) is a deadly cancer characterized by an expanded self-renewal capacity that is associated with the accumulation of immature myeloid cells. Emerging evidence shows that methyl-CpG-binding domain protein 2 (MBD2), a DNA methylation reader, often participates in the transcriptional silencing of hypermethylated genes in cancer cells. Nevertheless, the role of MBD2 in AML remains unclear. Herein, by using an MLL-AF9 murine model and a human AML cell line, we observed that loss of MBD2 could delay the initiation and progression of leukemia. MBD2 depletion significantly reduced the leukemia burden by decreasing the proportion of leukemic stem cells (LSCs) and inhibiting leukemia cell proliferation in serial transplantation experiments, thereby allowing leukemic blasts to transition to a more mature state reflecting normal myelopoiesis. Both gene expression analyses and bioinformatic studies revealed that MBD2 negatively modulated genes related to myeloid differentiation, and was necessary to sustain the MLL-AF9 oncogene-induced gene program. We further demonstrated that MBD2 could promote LSC cell cycle progression through epigenetic regulation of CDKN1C transcription probably by binding to its promoter region. Taken together, our data suggest that MBD2 promotes AML development and could be a therapeutic target for myeloid malignancies.

Leonurine-Repressed miR-18a-5p/SOCS5/JAK2/STAT3 Axis Activity Disrupts CML malignancy

Leonurine, an active natural alkaloid compound isolated from Herba leonuri, has been reported to exhibit promising anticancer activity in solid tumors. The aim of this study was to explore whether leonurine is able to inhibit chronic myeloid leukemia (CML) malignancy. Here, we found that leonurine dose dependently inhibited the proliferation, migration, colony formation and promoted apoptosis of CML cells. Furthermore, leonurine markedly reduced CML xenograft growth in vivo. Mechanically, leonurine upregulated SOCS5 expression, thus leading JAK2/STAT3 signaling suppression. Silencing of SOCS5 by its siRNA abrogated the effect of leonurine on CML cells, demonstrating that SOCS5 mediates the anti-leukemia effect of leonurine. Notably, we observed that miR-18a-5p was remarkably increased in CML cells. Treating CML cells with leonurine significantly decreased miR-18a-5p expression. Moreover, we found miR-18a-5p repressed SOCS5 by directly targeting its 3′-UTR. miR-18a-5p downregulation induced by leonurine reduced the biological activity of CML cells by relieving miR-18a-5p repression of SOCS5 expression. Taken together, leonurine exerts significant anti-leukemia efficacy in CML by regulating miR-18a-5p/SOCS5/JAK2/STAT3 axis.

Loss of MBD2 affects early T cell development by inhibiting the WNT signaling pathway

DNA methylation alters the expression of certain genes without any alteration to the DNA sequence and is a dynamic process during normal hematopoietic differentiation. As an epigenetic regulator, methyl-CpG-binding domain protein 2 (MBD2) is an important member of the MBD protein family and is acknowledged as a "reader" of DNA methylation. We used a mouse model to study the effects of MBD2 on the early development of T cells. Here, we found that MBD2 deficiency led to retardation of T cell differentiation at the DN3 stage. Meanwhile, decreased proliferative capacity and increased apoptosis were detected in Mbd2^-/- DN thymocytes. Furthermore, we found the WNT pathway was significantly down-regulated in Mbd2^-/- DN thymocytes: DKK1 (Dickkopf-1) expression was significantly increased, while TCF7 (transcription factor 7) and c-MYC were down-regulated. Thus, these findings established that MBD2 acted as a dominant regulator to imprint DN T cell development via the WNT pathway.

MBD2 Correlates with a Poor Prognosis and Tumor Progression in Renal Cell Carcinoma

Purpose

DNA methylation plays an important role in regulating gene expression. Methyl-CpG-binding domain (MBD) proteins recognize and bind to methylated DNA, which mediate gene silencing by the interaction with deacetylases and histone methyltransferases. MBD2 has been reported in various human cancers; however, its clinical implication and potential regulatory role in renal cell carcinoma (RCC) have not been elaborated.

Materials and Methods

In the study, we estimated the expression and prognostic value of MBD2 in RCC cell lines and tissues by Western blotting and immunohistochemistry. The associations of MBD2 expression and pathological characters and survival in RCC patients were performed using χ2 and Kaplan-Meier survival analysis, respectively. Univariate and multivariable Cox regression analyses suggested the independent predictors in RCC prognosis. The functional role of MBD2 in RCC progression was assessed by in vitro cell experiments. In addition, we identified the MBD2-mediated alterations of protein-related proliferation and EMT markers in RCC cells after MBD2 overexpression and knockdown.

Results

We found that the protein levels of MBD2 were upregulated in RCC cells and tissues. High MBD2 expression was related to TNM stage and predicted poorer survival in RCC. Enforced expression of MBD2 significantly promoted the proliferation, cycle progress, invasion and migration of RCC cells in vitro. However, downregulating MBD2 remarkably weakened the above cell functions. Mechanistically, the promotive effect of MBD2 overexpression may be regulated by its effects onp21, p53 and Cyclin D1 expression and EMT process.

Conclusion

These results indicated that MBD2confers an oncogenic function in the malignant progression of RCC. MBD2 could be served as a meaningful prognostic biomarker and a latent therapeutic target in RCC patients.

Expression and clinical significance of methyl-CpG binding domain protein 2 in high-grade serous ovarian cancer

Platinum resistance is an important cause of clinical recurrence and mortality of patients with high-grade serous ovarian cancer (HGSOC). Methyl-CpG binding domain protein 2 (MBD2) serves an important role in tumor progression; however, its role in HGSOC remains unclear. The aim of the present study was to investigate the expression of MBD2 in HGSOC and its role in drug resistance and prognosis of HGSOC. MBD2 expression was analyzed by immunohistochemical staining and western blotting. The associations between MBD2 expression and clinical pathological features, platinum resistance and patient prognosis were analyzed using a χ² test, Kaplan-Meier analysis and Cox regression analysis. Positive MBD2 expression was detected in 73 (63.5%) of the HGSOC tissue samples, whereas it was undetectable in all 16 normal tissue samples (100%) analyzed, indicating a significantly higher expression level in tumor tissues compared with normal tissues (P<0.001). Additionally, MBD2 expression was significantly higher in platinum-resistant cases compared with that in platinum-sensitive cases (P<0.05). In addition, high expression of MBD2 was negatively associated with relapse-free survival (P<0.05). In conclusion, MBD2 was demonstrated to be a potential drug target and a biomarker for poor prognosis in HGSOC.

The Effects of Low Selenium on DNA Methylation in the Tissues of Chickens

DNA methylation is involved in epigenetic mechanisms associated with gene suppression, and its abnormalities lead to gene instability and disease development. As an essential trace element in humans and animals, selenium (Se) is also associated with abnormal changes in DNA methylation. However, the effect of low Se on DNA methylation in avian tissues has not been reported. In the current study, chickens were fed a low-Se diet (0.033 mg Se/kg) or supplemented with 0.15 mg Se/kg as selenite for up to 55 days. DNA methylation levels were examined by high-performance liquid chromatography (HPLC). DNA methyltransferases (DNMTs) and methyl-DpG-binding domain protein 2 (MBD2) mRNA levels were examined through the applications of RT-PCR. The experiment aims to explore the relationship between low Se and DNA methylation. The results showed that total DNA methylation levels in the muscle tissues, brain, immune tissues, and liver of the low-selenium diet group were decreased compared with the control group. The degree of DNA methylation reduction in different tissues from largest to smallest was liver > cerebellum > thymus > brain > spleen ≥ leg muscles > pectoral muscles > bursa of Fabricius > thalamus > wing muscles. DNMT1, DNMT3A, and DNMT3B mRNA expression levels of the low-selenium diet group were decreased compared with those in the control group. The mRNA expression of the MBD2 gene was increased. The results indicate that low Se can reduce the DNA methylation levels of tissues, especially within the liver. These conclusions provide a basis for exploring the pathogenesis of selenium deficiency from the perspective of DNA methylation and create a new basis for comparative medicine.

Silencing of a novel lncRNA LOC105369748 suppresses the progression of hepatocellular carcinoma by sponging miR-5095 from MBD2

A growing number of studies have suggested that long noncoding RNAs (lncRNAs) play critical roles in human malignant cancers, including hepatocellular carcinoma (HCC). However, the functions of most lncRNAs have not been elucidated in HCC. In the present study, we explored the potential functions of a novel lncRNA LOC105369748 in the HCC progression. We identified that LOC105369748 expression was significantly elevated in HCC tissues compared with normal tissues based on bioinformatics analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis and in situ hybridization (ISH) examination. Moreover, we found that the LOC105369748 overexpression was associated with poor prognosis in patients with HCC. Then we measured the effects of LOC105369748 on HCC cell proliferation, migration, invasion, and epithelial-to-mesenchymal transition (EMT). And our results demonstrated that LOC105369748 exerted oncogenic roles. In terms of mechanism, LOC105369748 was shown to promote MBD2 expression through competitively binding to microRNA(miR)-5095 in HCC. In conclusion, our findings elucidate that the LOC105369748/miR-5095/MBD2 signaling axis regulates the HCC progression and may be a novel therapeutic avenue.