Structure of nucleosome-bound DNA methyltransferases DNMT3A and DNMT3B.

CpG methylation by de novo DNA methyltransferases (DNMTs) 3A and 3B is essential for mammalian development and differentiation and is frequently dysregulated in cancer1. These two DNMTs preferentially bind to nucleosomes, yet cannot methylate the DNA wrapped around the nucleosome core2, and they favour the methylation of linker DNA at positioned nucleosomes3,4. Here we present the cryo-electron microscopy structure of a ternary complex of catalytically competent DNMT3A2, the catalytically inactive accessory subunit DNMT3B3 and a nucleosome core particle flanked by linker DNA. The catalytic-like domain of the accessory DNMT3B3 binds to the acidic patch of the nucleosome core, which orients the binding of DNMT3A2 to the linker DNA. The steric constraints of this arrangement suggest that nucleosomal DNA must be moved relative to the nucleosome core for de novo methylation to occur.

Efficient activation of hundreds of LTR12C elements reveals cis-regulatory function determined by distinct epigenetic mechanisms.

Long terminal repeats (LTRs), which often contain promoter and enhancer sequences of intact endogenous retroviruses (ERVs), are known to be co-opted as cis-regulatory elements for fine-tuning host-coding gene expression. Since LTRs are mainly silenced by the deposition of repressive epigenetic marks, substantial activation of LTRs has been found in human cells after treatment with epigenetic inhibitors. Although the LTR12C family makes up the majority of ERVs activated by epigenetic inhibitors, how these epigenetically and transcriptionally activated LTR12C elements can regulate the host-coding gene expression remains unclear due to genome-wide alteration of transcriptional changes after epigenetic inhibitor treatments. Here, we specifically transactivated >600 LTR12C elements by using single guide RNA-based dCas9-SunTag-VP64, a site-specific targeting CRISPR activation (CRISPRa) system, with minimal off-target events. Interestingly, most of the transactivated LTR12C elements acquired the H3K27ac-marked enhancer feature, while only 20% were co-marked with promoter-associated H3K4me3 modifications. The enrichment of the H3K4me3 signal was intricately associated with downstream regions of LTR12C, such as internal regions of intact ERV9 or other types of retrotransposons. Here, we leverage an optimized CRISPRa system to identify two distinct epigenetic signatures that define LTR12C transcriptional activation, which modulate the expression of proximal protein-coding genes.

DNA strand asymmetry generated by CpG hemimethylation has opposing effects on CTCF binding.

CpG methylation generally occurs on both DNA strands and is essential for mammalian development and differentiation. Until recently, hemimethylation, in which only one strand is methylated, was considered to be simply a transitory state generated during DNA synthesis. The discovery that a subset of CCCTC-binding factor (CTCF) binding sites is heritably hemimethylated suggests that hemimethylation might have an unknown biological function. Here we show that the binding of CTCF is profoundly altered by which DNA strand is methylated and by the specific CTCF binding motif. CpG methylation on the motif strand can inhibit CTCF binding by up to 7-fold, whereas methylation on the opposite strand can stimulate binding by up to 4-fold. Thus, hemimethylation can alter binding by up to 28-fold in a strand-specific manner. The mechanism for sensing methylation on the opposite strand requires two critical residues, V454 and S364, within CTCF zinc fingers 7 and 4. Similar to methylation, CpG hydroxymethylation on the motif strand can inhibit CTCF binding by up to 4-fold. However, hydroxymethylation on the opposite strand removes the stimulatory effect. Strand-specific methylation states may therefore provide a mechanism to explain the transient and dynamic nature of CTCF-mediated chromatin interactions.

Electrochemical Synthesis of Urea: Co-Reduction of Nitrite and Carbon Dioxide on Binuclear Cobalt Phthalocyanine.

Exploration of molecular catalysts with the atomic-level tunability of molecular structures offers promising avenues for developing high-performance catalysts for the electrochemical co-reduction reaction of carbon dioxide (CO2) and nitrite (NO2 -) into value-added urea. In this work, a binuclear cobalt phthalocyanine (biCoPc) catalyst is prepared through chemical synthesis and applied as a C─N coupling catalyst toward urea. Achieving a remarkable Faradaic efficiency of 47.4% for urea production at -0.5 V versus reversible hydrogen electrode (RHE), this biCoPc outperforms many known molecular catalysts in this specific application. Its unique planar macromolecular structure and the increased valence state of cobalt promote the adsorption of nitrogenous and carbonaceous species, a critical factor in facilitating the multi-electron C─N coupling. Combining highly sensitive in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) with density functional theory (DFT) calculations, the linear adsorbed CO (COL) and bridge adsorbed CO (COB) is captured on biCoPc catalyst during the co-reduction reaction. COB, a pivotal intermediate in the co-reduction from CO2 and nitrite to urea, is evidenced to be labile and may be attacked by nitrite, promoting urea production. This work demonstrates the importance of designing molecular catalysts for efficient co-reduction of CO2 and nitrite to urea.

iPSC-Derived Airway Epithelial Cells: Progress, Promise, and Challenges.

Induced pluripotent stem cells (iPSCs) generated from somatic cell sources are pluripotent and capable of indefinite expansion in vitro. They provide an unlimited source of cells that can be differentiated into lung progenitor cells for potential clinical use in pulmonary regenerative medicine. This review gives a comprehensive overview of recent progress toward the use of iPSCs to generate proximal and distal airway epithelial cells and mix lung organoids. Furthermore, their potential applications and future challenges for the field are discussed, with a focus on the technological hurdles that must be cleared before stem cell therapeutics can be used for clinical treatment.

Design, Synthesis and Evaluation of Fluorescent Properties of Benzothiazole Derivatives.

Fluorescence imaging is conducive to establish a bridge between molecular biology and clinical medicine, and provides new tools for disease process research, early diagnosis, and efficacy evaluation, because of the advantages of rapid imaging and nondestructive detection. Herein, a series of fluorescent molecules with thiadiazole, or thiazole, or benzothiazole cores were designed and synthesized to develop more excellent fluorescent molecules in bio-imaging. According to theoretical and experimental methods, we found that benzothiazole derivative 14 B with conjugate expansion by (4-aminophenyl) ethynyl group was the most excellent fluorescent molecule among all the investigated compounds and exhibited low cytotoxicity and strong blue and green fluorescence by confocal cell imaging.

Lactobacillus rhamnosus GG alleviates colitis caused by chemotherapy via biofilm formation.

BACKGROUND AND AIM: Severe colitis is a common side effect of chemotherapy in cancer patients. In this study, we attempted to enhance the viability of probiotics in a gastric acid environment and improve the colitis induced by dextran sulfate sodium (DSS) and docetaxel. METHODS: We purified Lactobacillus from yogurt and estimated their growth at pH 6.8 and pH 2.0. In the further investigation, the bacterial biofilm formation was used to define the mechanism by which administration of Lactobacillus rhamnosus (LGG) via oral gavage alleviates the colitis and intestine permeability of the mice induced by DSS and docetaxel. The potential benefit of probiotics on the treatment of breast cancer metastasis has been assessed as well. RESULTS: Lactobacillus from yogurt growth was unexpectedly faster in the pH 2.0 than in the neutral pH medium during the first hour. LGG administered in the fasting state via oral gavage significantly improved the preventive effect in the colitis caused by DSS and docetaxel. LGG reduced the permeability of the intestine and decreased the expression of proinflammatory cytokines, TNF-α, IL-1ß, and IL-6, in colitis by biofilm formation. Increasing the docetaxel dose may reduce breast tumor growth and metastasis in the lung but did not benefit survival due to severe colitis. However, the LGG supplement significantly improved the survival of tumor-bearing mice following a high dose of docetaxel treatment. CONCLUSIONS: Our findings provide new insights into the potential mechanism of probiotic protection of the intestine and provide a novel therapeutic strategy to augment the chemotherapeutic treatment of tumors.

Chloroquine enhances the efficacy of chemotherapy drugs against acute myeloid leukemia by inactivating the autophagy pathway.

Current therapy for acute myeloid leukemia (AML) is largely hindered by the development of drug resistance of commonly used chemotherapy drugs, including cytarabine, daunorubicin, and idarubicin. In this study, we investigated the molecular mechanisms underlying the chemotherapy drug resistance and potential strategy to improve the efficacy of these drugs against AML. By analyzing data from ex vivo drug-response and multi-omics profiling public data for AML, we identified autophagy activation as a potential target in chemotherapy-resistant patients. In THP-1 and MV-4-11 cell lines, knockdown of autophagy-regulated genes ATG5 or MAP1LC3B significantly enhanced AML cell sensitivity to the chemotherapy drugs cytarabine, daunorubicin, and idarubicin. In silico screening, we found that chloroquine phosphate mimicked autophagy inactivation. We showed that chloroquine phosphate dose-dependently down-regulated the autophagy pathway in MV-4-11 cells. Furthermore, chloroquine phosphate exerted a synergistic antitumor effect with the chemotherapy drugs in vitro and in vivo. These results highlight autophagy activation as a drug resistance mechanism and the combination therapy of chloroquine phosphate and chemotherapy drugs can enhance anti-AML efficacy.

A booster hepatitis B vaccine for children with maternal HBsAg positivity before 2 years of age could effectively prevent vaccine breakthrough infections.

BACKGROUND: The long-term protective effect of hepatitis B vaccine (HepB), the incidence of hepatitis B virus (HBV) vaccine breakthrough infections (VBIs), and whether a booster HepB is necessary remain to be clarified in children born to mothers with chronic HBV infection. METHODS: Based on a long-term follow-up prospective cohort of 1177 hepatitis B surface antigen (HBsAg)-positive mothers and their paired infants which was established from 2009 to 2011, total 454 children with immunoprophylaxis success as determined by postvaccination serologic testing (PVST) at 7 months old were included in this study. Among the 454 children, 246 never had a booster HepB, and 208 children received a booster HepB from 1 to 5 years of age. Multivariate logistic regression analysis was used to analyse the risk factors for HBV VBIs. RESULTS: The hepatitis B surface antibody (anti-HBs) levels declined sharply from 7 months to 2 years old, and the anti-HBs seronegative rate in the children increased significantly from 2 years old. A total of 31 (6.83%) of the 454 children experienced VBIs, of which 7 had overt and 7 had occult HBV infections. Notably, 14 (45.16%) of the 31 children with VBIs were diagnosed at 2 years old, and all of them had anti-HBs positivity (> 10 mIU/mL) at 1 year old. Maternal hepatitis B e antigen (HBeAg) positivity, higher HBV DNA and HBsAg levels, lower initial infant anti-HBs levels and not receiving a booster HepB were independent risk factors for VBIs. The incidence of VBIs was significantly lower in children with a booster HepB than in nonboosted children (0.50 vs. 11.90%, P < 0.001), and none of the boosted children developed overt or occult HBV infection. The anti-HBs levels of 76.67% for the children with VBIs in the nonboosted group indicated positivity before VBIs was detected. CONCLUSIONS: After the primary full immunization with HepB, children born to mothers with chronic HBV infection, especially the children with maternal HBeAg positivity, high HBV DNA levels, high HBsAg levels and/or low initial infant anti-HBs levels, were at a high risk of VBIs, and a booster HepB for these children before 2 years old, instead of when their anti-HBs level is < 10 mIU/mL, could reduce the incidence of VBIs.

Switching roles for DNA and histone methylation depend on evolutionary ages of human endogenous retroviruses.

We provide a comprehensive genomic and epigenomic map of the more than 500,000 endogenous retroviruses (ERVs) and fragments that populate the intergenic regions of the human genome. The repressive epigenetic marks associated with the ERVs, particularly long terminal repeats (LTRs), show a remarkable switch in silencing mechanisms, depending on the evolutionary age of the LTRs. Young LTRs tend to be CpG rich and are mainly suppressed by DNA methylation, whereas intermediate age LTRs are associated predominantly with histone modifications, particularly histone H3 lysine 9 (H3K9) methylation. Young LTRs can be reactivated by treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) alone, but their level of expression is much increased by 5-aza-CdR treatment plus knockdown of one of several H3K9 methyltransferases or of the H3K27 methyltransferase EZH2. The removal of cytosine methylation led to rapid, widespread increases in H3K9me3 in the LTRs. Intermediate age LTRs had lower CpG densities and were not up-regulated by 5-aza-CdR treatment, but they were sensitive to knockdown of H3K9 methyltransferases. Unlike the situation in embryonic stem cells, the polycomb repressive complex (PRC2) has a minor role in LTR suppression by itself and is only a player after removal of cytosine methylation in the analyzed cancer cell line. Up-regulation of LTRs and induction of "viral mimicry" is rapidly becoming of interest for predicting cancer patient response to epigenetic therapies. Understanding the mechanism for LTR suppression is of major importance in order to improve patient treatment strategies.

Enhanced Sensitivity of Salmonella to Antimicrobial Blue Light Caused by Inactivating rfaC Gene Involved in Lipopolysaccharide Biosynthesis.

Salmonella is a global foodborne pathogen that causes human diseases ranging from mild gastroenteritis to severe systemic infections. Recently, antimicrobial blue light (aBL) showed effective bactericidal activity against a variety of bacteria (e.g., Salmonella) with varying efficiency. However, the antimicrobial mechanism of aBL has not been fully elucidated. Our previous report showed that the outer membrane (OM) is a key target of aBL. The major component of the OM, lipopolysaccharide (LPS), may play a role in aBL bactericidal effect. Therefore, the influence of LPS truncation on the sensitivity of Salmonella Typhimurium SL1344 to aBL was investigated for the first time. First, the rfaC gene in the SL1344 strain likely involved in linking lipid A to the core region of LPS was inactivated and the influence on LPS structure was verified in the mutant strain SL1344ΔrfaC. SL1344ΔrfaC showed a significant increase in sensitivity to aBL, and the bactericidal efficiency exceeded 8 log CFU at an aBL dose of 383 J/cm2, while that of its parental SL1344 strain approached 4 log CFU. To discover the possible mechanism of higher sensitivity, the permeability of OM was determined. Compared to SL1344, SL1344ΔrfaC showed 2.7-fold higher permeability of the OM at 20 J/cm2, this may explain the higher vulnerability of the OM to aBL. Furthermore, the fatty acid profile was analyzed to reveal the detailed changes in the OM and inner membrane of the mutant. Results showed that the membrane lipids of SL1344ΔrfaC were markedly different to SL1344, indicating that change in fatty acid profile might mediate the enhancement of OM permeability and the increased sensitivity to aBL in SL1344ΔrfaC. Hence, we concluded that disruption of rfaC in Salmonella Typhimurium led to the formation of truncated LPS and thus enhanced the permeability of the OM, which contributed to the increased sensitivity to aBL.

Study on the mechanism of treating COVID-19 with Shenqi Wan based on network pharmacology.

PURPOSE: Through the method of network pharmacology, the active components and targets of Shenqi Wan (SQW) were excavated, the relationship with novel Coronavirus pneumonia (COVID-19) was discussed, and the possible mechanism of SQW in the treatment of COVID-19 was revealed from the aspects of multicomponents, multitargets, and multipathways. METHODS: Firstly, the active components of SQW were screened from traditional Chinese medicine systems pharmacology database and analysis platform and the 2020 edition of Chinese Pharmacopeia, and the related targets of the components were obtained. Then the disease targets related to COVID-19 were screened from GeneCards and Online Mendelian Inheritance in Man. Venny was used to map the relationship between component-target and disease-target, and String was used to analyze the interaction of common targets. The network was constructed and analyzed by Cytoscape, the function of Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) genes was enriched by Metascape, and the molecular docking was verified by CB-Dock. RESULTS: Finally, 45 active components of SQW were obtained, and 72 potential targets were related to COVID-19, angiotensin-converting enzyme 2 (ACE2), interleukin (IL)-6, nitric oxide synthase (NOS3) and, C-reactive protein (CRP),may be the key targets. GO enrichment of 1715 projects, such as lipopolysaccharide stress response, active oxygen metabolism, positive regulation of cell migration, and other GO enrichment. About 136 KEGG pathways, tumor necrosis factor signaling pathway, IL-17 signaling pathway, hypoxia-inducible factor 1-α signaling pathway were obtained. Molecular docking showed that kaempferol, quercetin, luteolin, astragaloside, calyx isoflavone glucoside, matrine, and other COVID-19-related targets such as ACE2, chymotrypsin-like protease (3CLpro), papain-like protease (PLpro), prostaglandin-endoperoxide synthase 2 (PTGS2) have good binding ability. CONCLUSION: According to the above results, it is suggested that SQW may play a role in the treatment of COVID-19 by directly or indirectly combining kaempferol, quercetin, and luteolin with ACE2, 3CLpro, PLpro, and PTGS2 to regulate multiple biological functions and signaling pathways.

[Study on mechanism of combination of Platycodonis Radix and Lilii Bulbus with homology of medicine and food in treating pneumonia].

To investigate the potential molecular mechanism of the combination of Platycodonis Radix and Lilii Bulbus with the homology of medicine and food in the treatment of pneumonia by means of network pharmacology and in vitro verification experiment. Under the condition of bioavailability(OB)≥30% and drug-like(DL)≥0.18, the active components of Platycodonis Radix and Lilii Bulbus were screened in TCMSP database; the prediction targets of active components were searched from TCMSP, DrugBank and other databases, and the potential targets of pneumonia were obtained through GeneCards and OMIM database. The common targets were obtained by the intersection of drug and disease targets. The PPI network of common targets was constructed by STRING 11.0, and the core targets were obtained by topological analysis. Then the core targets received GO and KEGG analysis with use of WebGestalt and Metascape. The "component-target-pathway" network was constructed with the help of Cytoscape 3.7.1 software, and the component-target molecular docking verification was carried out with Discovery Studio 2016 software. Finally, the core targets and pathways were preliminarily verified in vitro. In this study, 12 active components were screened, 225 drug prediction targets and 420 potential diseases targets were obtained based on data mining method, and 14 core targets were obtained by topological analysis, including TNF, MMP9, AKT1, IL4 and IL2. The enrichment results of GO and KEGG showed that "Platycodonis Radix and Lilii Bulbus" drug pair may regulate inflammation, cell growth and metabolism by acting on 20 key signaling pathways such as TNF and IL-17, thereby exerting anti-pneumonia effects. The results of molecular docking showed that 12 active components had good binding ability with 14 core targets. In vitro experiment results showed that the core components of "Platycodonis Radix and Lilii Bulbus" drug pair could inhibit the expression of MMP9 and TNF-α by regulating TNF signal pathway. This study confirmed the scientificity and reliability of the prediction results of network pharmacology, and preliminarily revealed the potential molecular mechanism of the compatibility of Platycodonis Radix and Lilii Bulbus in the treatment of pneumonia. It provides a novel insight on systematically exploring the mechanism of the compatible use of Platycodonis Radix and Lilii Bulbus, and has a certain reference value for the research, development and application of new drugs.

NADPH oxidases and the evolution of plant salinity tolerance.

Soil salinization is a major threat to global food security and the biodiversity of natural ecosystems. To adapt to salt stress, plants rely on ROS-mediated signalling networks that operate upstream of a broad array of physiological and genetic processes. A key player in ROS signalling is NADPH oxidase, a plasma-membrane-bound enzyme encoded by RBOH genes. In this study, we have conducted a comprehensive bioinformatic analysis of over 50 halophytic and glycophytic species to link the difference in the kinetics of ROS signalling between contrasting species with the abundance and/or structure of NADPH oxidases. The RBOH proteins were predicted in all the tested plant lineages except some algae species from the Rhodophyta, Chlorophyta and Streptophyta. Within the glycophytic group, the number of RBOH copies correlated negatively with salinity stress tolerance, suggesting that a reduction in the number of RBOH isoforms may be potentially related to the evolution of plant salinity tolerance. While halophytes did not develop unique protein families during evolution, they evolved additional phosphorylation target sites at the N-termini of NADPH oxidases, potentially modulating enzyme activity and allowing more control over their function, resulting in more efficient ROS signalling and adaptation to saline conditions.

Arterial Supercharging Is More Beneficial to Flap Survival Due to Quadruple Dilation of Venules.

BACKGROUND: "Choke vessels" are communicating conduits between adjacent perforasomes in the skin. Most researches focus mainly on the arterial aspect of the "choke vessels" and neglect the venous aspect, an imbalance needed to be addressed. MATERIALS AND METHODS: The study was divided into parts I, II, and III. Part I was for observation of the vascular morphological evolution in the choke zone after flap harvest in rats. Part II was for determination of the importance of the dilation of the arterial and venous components of "choke vessels" by preserving the iliolumbar artery (ILA group) or vein (ILV group). A laser Doppler flowmeter and a speckle flow imaging system were adopted for monitoring the hemodynamic impact caused by the different manipulation. Part III was for corroboration of part II by manipulation of other vessels. RESULTS: In part I, the arteries and veins between the iliolumbar and intercostal perforasomes underwent modest dilation, whereas the venules between the veins nearly quadrupled in diameter. In part II, flaps in the ILA group were much more intensive in blood perfusion than flaps in the ILV group. The flap necrosis rate was 0.31 ± 0.07 in the ILV group, being significantly larger than 0.10 ± 0.03 in the ILA group. Part III confirmed that venous superdrainage is less efficacious in reducing flap necrosis than arterial supercharging, in which the position of the additional artery was far more important than the diameter. CONCLUSIONS: The extensive dilation of the venous component of choke vessels makes a more potent compensatory role for venous drainage after flap harvest, indicating arterial supercharging is better in augmenting flap viability than venous superdrainage.

Vitamin C - A new player in regulation of the cancer epigenome.

Over the past few years it has become clear that vitamin C, as a provider of reduced iron, is an essential factor for the function of epigenetic regulators that initiate the demethylation of DNA and histones. Vitamin C deficiency is rare in the general population, but is frequently observed in patients with cancer. Genes encoding epigenetic regulators are often mutated in cancer, underscoring their central roles in carcinogenesis. In hematological cancers, such as acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), drugs that reverse epigenetic aberrations are now the standard of care. Recent in vitro studies suggest that vitamin C at physiological concentrations, combined with hypomethylating agents may act synergistically to cause DNA demethylation through active and passive mechanisms, respectively. Additionally, several recent studies have renewed interest in the use of pharmacological doses of vitamin C injected intravenously to selectively kill tumor cells. This review will focus on the potential of vitamin C to optimize the outcome of epigenetic therapy in cancer patients and alternatively to act as a therapeutic at high doses.

High-Indexed PtNi Alloy Skin Spiraled on Pd Nanowires for Highly Efficient Oxygen Reduction Reaction Catalysis.

The catalytic performance of Pt-based catalysts for oxygen reduction reactions (ORR) can generally be enhanced by constructing high-index exposed facets (HIFs). However, the synthesis of Pt alloyed high-index skins on 1D non-Pt surfaces to further improve Pt utilization and stability remains a fundamental challenge for practical nanocrystals. In this work, Pd nanowires (NWs) are selected as a rational medium to facilitate the epitaxial growth of Pt and Ni. Based on the different nucleation and growth habits of Pt and Ni, a continuous PtNi alloy skin bounded with HIFs spiraled on a Pd core can be obtained. Here, the as-prepared helical Pd@PtNi NWs possess high HIF densities, low Pt contents, and optimized oxygen adsorption energies, demonstrating an enhanced ORR mass activity of 1.75 A mgPt -1 and a specific activity of 3.18 mA cm-2 , which are 10 times and 12 times higher than commercial Pt/C catalysts, respectively. In addition, the 1D nanostructure enables the catalyst to be highly stable after 30 000 potential sweeping cycles. This work successfully extends bulky high-indexed Pt alloys to core-shell nanostructures with the design of a new, highly efficient and stable Pt-based catalyst for fuel cells.

Integrative Epigenetic Analysis Reveals Therapeutic Targets to the DNA Methyltransferase Inhibitor Guadecitabine (SGI-110) in Hepatocellular Carcinoma.

There is an urgent need to develop more effective therapies for hepatocellular carcinoma (HCC) because of its aggressiveness. Guadecitabine (SGI-110) is a second-generation DNA methyltransferase inhibitor (DNMTi), which is currently in clinical trials for HCC and shows greater stability and performance over first-generation DNMTis. In order to identify potential therapeutic targets of SGI-110 for clinical trials, HCC cell lines (SNU398, HepG2, and SNU475) were used to evaluate the effects of transient SGI-110 treatment by an integrative analysis of DNA methylation, nucleosome accessibility, gene expression profiles, and its clinical relevance by comparison to The Cancer Genome Atlas (TCGA) HCC clinical data. Each HCC cell line represents a different DNA methylation subtype of primary HCC tumors based on TCGA data. After SGI-110 treatment, all cell lines were sensitive to SGI-110 with prolonged antiproliferation effects. Expression of up-regulated genes, including tumor suppressors, was positively correlated with nucleosome accessibility and negatively correlated with gene promoter DNA methylation. Alternatively, expression of down-regulated genes, such as oncogenes, was negatively correlated with nucleosome accessibility and positively correlated with gene body DNA methylation. SGI-110 can also act as a dual inhibitor to down-regulate polycomb repressive complex 2 (PRC2) genes by demethylating their gene bodies, resulting in reactivation of PRC2 repressed genes without involvement of DNA methylation. Furthermore, it can up-regulate endogenous retroviruses to reactivate immune pathways. Finally, about 48% of frequently altered genes in primary HCC tumors can be reversed by SGI-110 treatment. CONCLUSION: Our integrative analysis has successfully linked the antitumor effects of SGI-110 to detailed epigenetic alterations in HCC cells, identified potential therapeutic targets, and provided a rationale for combination treatments of SGI-110 with immune checkpoint therapies.

Vitamin C increases viral mimicry induced by 5-aza-2'-deoxycytidine.

Vitamin C deficiency is found in patients with cancer and might complicate various therapy paradigms. Here we show how this deficiency may influence the use of DNA methyltransferase inhibitors (DNMTis) for treatment of hematological neoplasias. In vitro, when vitamin C is added at physiological levels to low doses of the DNMTi 5-aza-2'-deoxycytidine (5-aza-CdR), there is a synergistic inhibition of cancer-cell proliferation and increased apoptosis. These effects are associated with enhanced immune signals including increased expression of bidirectionally transcribed endogenous retrovirus (ERV) transcripts, increased cytosolic dsRNA, and activation of an IFN-inducing cellular response. This synergistic effect is likely the result of both passive DNA demethylation by DNMTi and active conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) by ten-eleven translocation (TET) enzymes at LTR regions of ERVs, because vitamin C acts as a cofactor for TET proteins. In addition, TET2 knockout reduces the synergy between the two compounds. Furthermore, we show that many patients with hematological neoplasia are markedly vitamin C deficient. Thus, our data suggest that correction of vitamin C deficiency in patients with hematological and other cancers may improve responses to epigenetic therapy with DNMTis.

Anti-inflammatory effects of Chinese propolis in lipopolysaccharide-stimulated human umbilical vein endothelial cells by suppressing autophagy and MAPK/NF-κB signaling pathway.

This study aimed to investigate the possible benefits of Chinese poplar propolis (CP) in inhibiting inflammation using vascular endothelial cells (VECs) cultured in a nutrient-rich condition exposed to lipopolysaccharide (LPS). Cell proliferation was detected by sulforhodamine B assay and EdU kit. The production of reactive oxygen species (ROS) and level of mitochondrial membrane potential were determined with fluorescent probe DCHF and JC-1, respectively. Protein expression was examined by immunofluorescence staining and western blotting. The results showed that CP (6.25, 12.5, and 25 µg/mL) significantly reduced LPS-induced cytotoxicity, and when challenged with CP substantially suppressed ROS overproduction and protected mitochondrial membrane potential. CP treatment significantly inhibited autophagy by inhibiting LC3B distribution and accumulation, and elevating the p62 level in an mTOR-independent manner but mainly by suppressing the translocation of p53 from the cytoplasm to the nucleus. Furthermore, CP treatment markedly reduced protein levels of TLR4 at 12 and 24 h and significantly suppressed nuclear translocation of NF-κB p65 from cytoplasm to nucleus. In addition, CP treatment significantly reduced the phosphorylation of JNK, ERK1/2, and p38 MAPK. Our findings demonstrated that CP protects VECs from LPS-induced oxidative stress and inflammation, which might be associated with depressing autophagy and MAPK/NF-κB signaling pathway. The results provided novel insights for the potential use of nutrient-rich propolis against inflammation.