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Molecular Medicine (Cambridge, Mass.) Jun 2024Ketone β-hydroxybutyrate (BHB) has been reported to prevent tumor cell proliferation and improve drug resistance. However, the effectiveness of BHB in oxaliplatin...
BACKGROUND
Ketone β-hydroxybutyrate (BHB) has been reported to prevent tumor cell proliferation and improve drug resistance. However, the effectiveness of BHB in oxaliplatin (Oxa)-resistant colorectal cancer (CRC) and the underlying mechanism still require further proof.
METHODS
CRC-Oxa-resistant strains were established by increasing concentrations of CRC cells to Oxa. CRC-Oxa cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) were checked following BHB intervention in vitro. The subcutaneous and metastasis models were established to assess the effects of BHB on the growth and metastasis of CRC-Oxa in vivo. Eight Oxa responders and seven nonresponders with CRC were enrolled in the study. Then, the serum BHB level and H3K79me, H3K27ac, H3K14ac, and H3K9me levels in tissues were detected. DOT1L (H3K79me methyltransferase) gene knockdown or GNE-049 (H3K27ac inhibitor) use was applied to analyze further whether BHB reversed CRC-Oxa resistance via H3K79 demethylation and/or H3K27 deacetylation in vivo and in vitro.
RESULTS
Following BHB intervention based on Oxa, the proliferation, migration, invasion, and EMT of CRC-Oxa cells and the growth and metastasis of transplanted tumors in mice were suppressed. Clinical analysis revealed that the differential change in BHB level was associated with drug resistance and was decreased in drug-resistant patient serum. The H3K79me, H3K27ac, and H3K14ac expressions in CRC were negatively correlated with BHB. Furthermore, results indicated that H3K79me inhibition may lead to BHB target deletion, resulting in its inability to function.
CONCLUSIONS
β-hydroxybutyrate resensitized CRC cells to Oxa by suppressing H3K79 methylation in vitro and in vivo.
Topics: Oxaliplatin; Colorectal Neoplasms; Humans; 3-Hydroxybutyric Acid; Animals; Mice; Histones; Methylation; Cell Line, Tumor; Drug Resistance, Neoplasm; Cell Proliferation; Xenograft Model Antitumor Assays; Male; Epithelial-Mesenchymal Transition; Female; Antineoplastic Agents; Cell Movement; Apoptosis; Mice, Nude
PubMed: 38910244
DOI: 10.1186/s10020-024-00864-1 -
Communications Biology Jun 2024N-methyltransferase (NMT)-catalyzed methylation at the termini of nonribosomal peptides (NRPs) has rarely been reported. Here, we discover a fungal NMT LcsG for the...
N-methyltransferase (NMT)-catalyzed methylation at the termini of nonribosomal peptides (NRPs) has rarely been reported. Here, we discover a fungal NMT LcsG for the iterative terminal N-methylation of a family of NRPs, leucinostatins. Gene deletion results suggest that LcsG is essential for leucinostatins methylation. Results from in vitro assays and HRESI-MS-MS analysis reveal the methylation sites as NH, NHCH and N(CH) in the C-terminus of various leucinostatins. LcsG catalysis yields new lipopeptides, some of which demonstrate effective antibiotic properties against the human pathogen Cryptococcus neoformans and the plant pathogen Phytophthora infestans. Multiple sequence alignments and site-directed mutagenesis of LcsG indicate the presence of a highly conserved SAM-binding pocket, along with two possible active site residues (D368 and D395). Molecular dynamics simulations show that the targeted N can dock between these two residues. Thus, this study suggests a method for increasing the variety of natural bioactivity of NPRs and a possible catalytic mechanism underlying the N-methylation of NRPs.
Topics: Methyltransferases; Methylation; Hypocreales; Cryptococcus neoformans; Fungal Proteins; Molecular Dynamics Simulation; Phytophthora infestans; Amino Acid Sequence; Mutagenesis, Site-Directed; Catalytic Domain; Antimicrobial Cationic Peptides
PubMed: 38909167
DOI: 10.1038/s42003-024-06467-0 -
The Journal of Investigative Dermatology Jun 2024Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high mortality rate. MC polyomavirus (MCPyV) causes 80% of MCCs, encoding the viral oncogenes small T...
Merkel cell carcinoma (MCC) is an aggressive skin cancer with a high mortality rate. MC polyomavirus (MCPyV) causes 80% of MCCs, encoding the viral oncogenes small T (sT) and truncated large T antigens (tLT). These proteins impair the Rb1-dependent G1/S checkpoint blockade and subvert the host cell epigenome to promote cancer. Whole proteome analysis and proximal interactomics identified a tLT-dependent deregulation of DNA damage response (DDR). Our investigation revealed a previously unreported interaction between tLT and the histone methyltransferase EHMT2, to our knowledge. T Antigens knockdown reduced DDR protein levels and increased levels of the DNA damage marker γH2Ax. EHMT2 normally promotes H3K9 methylation and DDR signaling. Given that inhibition of EHMT2 did not significantly change the MCC cells proteome, tLT-EHMT2 interaction could affect the DDR. With tLT, we report that EHMT2 gained DNA damage repair proximal interactors. EHMT2 inhibition rescued proliferation in MCC cells depleted for their T antigens, suggesting impaired DDR and/or lack of checkpoint efficiency. Combined tLT and EHMT2 inhibition led to altered DDR, evidenced by multiple signaling alterations. Here we show that tLT hijacks multiple components of the DNA damage machinery to enhance tolerance to DNA damage in MCC cells, which could explain the genetic stability of these cancers.
PubMed: 38908781
DOI: 10.1016/j.jid.2024.04.034 -
Environment International Jun 2024Microbially-mediated arsenic biotransformation plays a pivotal role in the biogeochemical cycling of arsenic; however, the presence of arsenic biotransformation genes...
Microbially-mediated arsenic biotransformation plays a pivotal role in the biogeochemical cycling of arsenic; however, the presence of arsenic biotransformation genes (ABGs) in urban dust remains unclear. To investigate the occurrence and spatiotemporal distributions of ABGs, a total of one hundred and eighteen urban dust samples were collected from different districts of Xiamen city, China in summer and winter. Although inorganic arsenic species, including arsenate [As(V)] and arsenite [As(III)], were found to be predominant, the methylated arsenicals, particularly trimethylarsine oxide [TMAs(V)O] and dimethylarsenate [DMAs(V)], were detected in urban dust. Abundant ABGs were identified in urban dust via AsChip analysis (a high-throughput qPCR chip for ABGs), of which As(III) S-adenosylmethionine methyltransferase genes (arsM), As(V) reductase genes (arsC), As(III) oxidase genes (aioA), As(III) transporter genes (arsB), and arsenic-sensing regulator genes (arsR) were the most prevalent, collectively constituting more than 90 % of ABGs in urban dust. Microbes involved in arsenic methylation were assigned to bacteria (e.g., Actinomycetes and Alphaproteobacteria), archaea (e.g., Halobacteria), and eukaryotes (e.g., Chlamydomonadaceae) in urban dust via the arsM amplicon sequencing. Temperature, a season-dependent environmental factor, profoundly affected the abundance of ABGs and the composition of microbes involved in arsenic methylation. This study provides new insights into the presence of ARGs within the urban dust.
PubMed: 38908273
DOI: 10.1016/j.envint.2024.108823 -
Annals of Clinical Microbiology and... Jun 2024Escherichia. coli is the most frequent host for New Delhi metallo-β-lactamase (NDM) which hydrolyzes almost all β-lactams except aztreonam. The worldwide spread of...
BACKGROUND
Escherichia. coli is the most frequent host for New Delhi metallo-β-lactamase (NDM) which hydrolyzes almost all β-lactams except aztreonam. The worldwide spread of blaNDM-carrying E. coli heavily threatens public health.
OBJECTIVE
This study aimed to explore the global genomic epidemiology of blaNDM- carrying E. coli isolates, providing information for preventing the dissemination of such strains.
METHODS
Global E. coli genomes were downloaded from NCBI database and blaNDM was detected using BLASTP. Per software was used to extract meta information on hosts, resources, collection data, and countries of origin from GenBank. The sequence types (STs) and distribution of antimicrobial resistance gene (ARG) were analyzed by CLC Workbench; Plasmid replicons, serotypes and virulence genes (VFs) were analyzed by submitting the genomes to the websites. Statistical analyses were performed to access the relationships among ARGs and plasmid replicons.
RESULTS
Until March 2023, 1,774 out of 33,055 isolates collected during 2003-2022 were found to contain blaNDM in total. Among them, 15 blaNDM variants were found with blaNDM-5 (74.1%) being most frequent, followed by blaNDM-1 (16.6%) and blaNDM-9 (4.6%). Among the 213 ARGs identified, 27 blaCTX-M and 39 blaTEM variants were found with blaCTX-M-15 (n = 438, 24.7%) and blaTEM-1B (n = 1092, 61.6%) being the most frequent ones, respectively. In addition, 546 (30.8%) plasmids mediated ampC genes, 508 (28.6%) exogenously acquired 16 S rRNA methyltransferase encoding genes and 262 (14.8%) mcr were also detected. Among the 232 distinct STs, ST167 (17.2%) were the most prevalent. As for plasmids, more than half of isolates contained IncFII, IncFIB and IncX3. The VF terC, gad, traT and iss as well as the serotypes O101:H9 (n = 231, 13.0%), O8:H9 (n = 115, 6.5%) and O9:H30 (n = 99, 5.6%) were frequently observed.
CONCLUSIONS
The study delves into the intricate relationship between plasmid types, virulence factors, and ARGs, which provides valuable insights for clinical treatment and public health interventions, and serves as a critical resource for guiding future research, surveillance, and implementation of effective strategies to address the challenges posed by blaNDM-carrying E. coli. The findings underscore the urgent need for sustained global collaboration, surveillance efforts, and antimicrobial stewardship to mitigate the impact of these highly resistant strains on public health.
Topics: Escherichia coli; beta-Lactamases; Escherichia coli Infections; Plasmids; Humans; Genome, Bacterial; Anti-Bacterial Agents; Microbial Sensitivity Tests; Genomics; Virulence Factors; Virulence; Global Health
PubMed: 38907245
DOI: 10.1186/s12941-024-00719-x -
Life Science Alliance Sep 2024H3.1 histone is predominantly synthesized and enters the nucleus during the G1/S phase of the cell cycle, as a new component of duplicating nucleosomes. Here, we found...
H3.1 histone is predominantly synthesized and enters the nucleus during the G1/S phase of the cell cycle, as a new component of duplicating nucleosomes. Here, we found that p53 is necessary to secure the normal behavior and modification of H3.1 in the nucleus during the G1/S phase, in which p53 increases C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1) levels and decreases enhancer of zeste homolog 2 (EZH2) levels in the H3.1 interactome. In the absence of p53, H3.1 molecules tended to be tethered at or near the nuclear envelope (NE), where they were predominantly trimethylated at lysine 27 (H3K27me3) by EZH2, without forming nucleosomes. This accumulation was likely caused by the high affinity of H3.1 toward phosphatidic acid (PA). p53 reduced nuclear PA levels by increasing levels of CTDNEP1, which activates lipin to convert PA into diacylglycerol. We moreover found that the cytosolic H3 chaperone HSC70 attenuates the H3.1-PA interaction, and our molecular imaging analyses suggested that H3.1 may be anchored around the NE after their nuclear entry. Our results expand our knowledge of p53 function in regulation of the nuclear behavior of H3.1 during the G1/S phase, in which p53 may primarily target nuclear PA and EZH2.
Topics: Histones; Tumor Suppressor Protein p53; Cell Nucleus; Humans; Enhancer of Zeste Homolog 2 Protein; G1 Phase; S Phase; Nuclear Envelope; Methylation; Animals; Nucleosomes
PubMed: 38906678
DOI: 10.26508/lsa.202402835 -
Life Science Alliance Sep 2024Decitabine and azacytidine are considered as epigenetic drugs that induce DNA methyltransferase (DNMT)-DNA crosslinks, resulting in DNA hypomethylation and damage....
Decitabine and azacytidine are considered as epigenetic drugs that induce DNA methyltransferase (DNMT)-DNA crosslinks, resulting in DNA hypomethylation and damage. Although they are already applied against myeloid cancers, important aspects of their mode of action remain unknown, highly limiting their clinical potential. Using a combinatorial approach, we reveal that the efficacy profile of both compounds primarily depends on the level of induced DNA damage. Under low DNMT activity, only decitabine has a substantial impact. Conversely, when DNMT activity is high, toxicity and cellular response to both compounds are dramatically increased, but do not primarily depend on DNA hypomethylation or RNA-associated processes. By investigating proteome dynamics on chromatin, we show that decitabine induces a strictly DNMT-dependent multifaceted DNA damage response based on chromatin recruitment, but not expression-level changes of repair-associated proteins. The choice of DNA repair pathway hereby depends on the severity of decitabine-induced DNA lesions. Although under moderate DNMT activity, mismatch (MMR), base excision (BER), and Fanconi anaemia-dependent DNA repair combined with homologous recombination are activated in response to decitabine, high DNMT activity and therefore immense replication stress induce activation of MMR and BER followed by non-homologous end joining.
Topics: Decitabine; DNA Damage; Humans; DNA Repair; DNA Methylation; Azacitidine; Antimetabolites, Antineoplastic; Cell Line, Tumor; DNA (Cytosine-5-)-Methyltransferases; Chromatin; DNA Modification Methylases
PubMed: 38906675
DOI: 10.26508/lsa.202302437 -
Journal of Chromatography. B,... Jun 2024Decitabine is a DNA methyltransferase inhibitor used in the treatment of acute myeloid leukemia and myelodysplastic syndrome. The notion that ongoing trials are...
Decitabine is a DNA methyltransferase inhibitor used in the treatment of acute myeloid leukemia and myelodysplastic syndrome. The notion that ongoing trials are presently exploring the combined use of decitabine, with or without the cytidine deaminase inhibitor cedazuridine, and other antileukemic drugs necessitates a comprehensive understanding of pharmacokinetic properties and an evaluation of drug-drug interaction liabilities. We report here the development and validation of a sensitive UHPLC-MS/MS method for quantifying decitabine in mouse plasma, which should be useful for such studies. The method involved a one-step protein precipitation extraction, and chromatographic separation on an XBridge HILIC column using gradient elution. The method was found to be robust, accurate, precise, and sufficiently sensitive (lower limit of quantitation, 0.4 ng/mL) to determine decitabine concentrations in microvolumes of plasma from mice receiving the agent orally or intravenously in the presence or absence of cedazuridine.
PubMed: 38905720
DOI: 10.1016/j.jchromb.2024.124209 -
Molecular Biology Reports Jun 2024SETDB1 (SET domain bifurcated-1) is a histone H3-lysine 9 (H3K9)-specific methyltransferase that mediates heterochromatin formation and repression of target genes....
BACKGROUND
SETDB1 (SET domain bifurcated-1) is a histone H3-lysine 9 (H3K9)-specific methyltransferase that mediates heterochromatin formation and repression of target genes. Despite the assumed functional link between DNA methylation and SETDB1-mediated H3K9 trimethylations, several studies have shown that SETDB1 operates autonomously of DNA methylation in a region- and cell-specific manner. This study analyzes SETDB1-null HAP1 cells through a linked methylome and transcriptome analysis, intending to explore genes controlled by SETDB1-involved DNA methylation.
METHODS AND RESULTS
We investigated SETDB1-mediated regulation of DNA methylation and gene transcription in human HAP1 cells using reduced-representation bisulfite sequencing (RRBS) and RNA sequencing. While two-thirds of differentially methylated CpGs (DMCs) in genic regions were hypomethylated in SETDB1-null cells, we detected a plethora of C2H2-type zinc-finger protein genes (C2H2-ZFP, 223 of 749) among the DMC-associated genes. Most C2H2-ZFPs with DMCs in their promoters were found hypomethylated in SETDB1-KO cells, while other non-ZFP genes with promoter DMCs were not. These C2H2-ZFPs with DMCs in their promoters were significantly upregulated in SETDB1-KO cells. Similarly, C2H2-ZFP genes were upregulated in SETDB1-null 293T cells, suggesting that SETDB1's function in ZFP gene repression is widespread. There are several C2H2-ZFP gene clusters on chromosome 19, which were selectively hypomethylated in SETDB1-KO cells.
CONCLUSIONS
SETDB1 collectively and specifically represses a substantial fraction of the C2H2-ZFP gene family. Through the en-bloc silencing of a set of ZFP genes, SETDB1 may help establish a panel of ZFP proteins that are expressed cell-type specifically and thereby can serve as signature proteins for cellular identity.
Topics: Histone-Lysine N-Methyltransferase; Humans; Zinc Fingers; DNA Methylation; Promoter Regions, Genetic; Up-Regulation; DNA Demethylation; Cell Line; CpG Islands; Gene Deletion; Histones
PubMed: 38904842
DOI: 10.1007/s11033-024-09703-2 -
International Journal of Biological... 2024N-methyladenosine (mA) methylation plays a crucial role in various biological processes and the pathogenesis of human diseases. However, its role and mechanism in kidney...
N-methyladenosine (mA) methylation plays a crucial role in various biological processes and the pathogenesis of human diseases. However, its role and mechanism in kidney fibrosis remain elusive. In this study, we show that the overall level of mA methylated RNA was upregulated and the mA methyltransferase METTL3 was induced in kidney tubular epithelial cells in mouse models and human kidney biopsies of chronic kidney disease (CKD). Proximal tubule-specific knockout of METTL3 in mice protected kidneys against developing fibrotic lesions after injury. Conversely, overexpression of METTL3 aggravated kidney fibrosis . Through bioinformatics analysis and experimental validation, we identified β-catenin mRNA as a major target of METTL3-mediated mA modification, which could be recognized by a specific mA reader, the insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3). METTL3 stabilized β-catenin mRNA, increased β-catenin protein and induced its downstream profibrotic genes, whereas either knockdown of IGF2BP3 or inhibiting β-catenin signaling abolished its effects. Collectively, these results indicate that METTL3 promotes kidney fibrosis by stimulating the mA modification of β-catenin mRNA, leading to its stabilization and its downstream profibrotic genes expression. Our findings suggest that targeting METTL3/IGF2BP3/β-catenin pathway may be a novel strategy for the treatment of fibrotic CKD.
Topics: beta Catenin; Animals; Mice; Fibrosis; Humans; Methylation; Methyltransferases; Signal Transduction; Adenosine; Kidney; Male; Mice, Inbred C57BL; Up-Regulation; Renal Insufficiency, Chronic; Mice, Knockout; RNA Methylation
PubMed: 38904026
DOI: 10.7150/ijbs.96233