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Cancers Jun 2024Antibacterial fluoroquinolones have emerged as potential anticancer drugs, thus prompting the synthesis of novel molecules with improved cytotoxic characteristics....
Antibacterial fluoroquinolones have emerged as potential anticancer drugs, thus prompting the synthesis of novel molecules with improved cytotoxic characteristics. Ciprofloxacin and norfloxacin derivatives, previously synthesized by our group, showed higher anticancer potency than their progenitors. However, no information about their mechanisms of action was reported. In this study, we selected the most active among these promising molecules and evaluated, on a panel of breast (including those triple-negative) and bladder cancer cell lines, their ability to induce cell cycle alterations and apoptotic and necrotic cell death through cytofluorimetric studies. Furthermore, inhibitory effects on cellular migration, metalloproteinase, and/or acetylated histone protein levels were also evaluated by the scratch/wound healing assay and Western blot analyses, respectively. Finally, the DNA relaxation assay was performed to confirm topoisomerase inhibition. Our results indicate that the highest potency previously observed for the derivatives could be related to their ability to induce G2/M cell cycle arrest and apoptotic and/or necrotic cell death. Moreover, they inhibited cellular migration, probably by reducing metalloproteinase levels and histone deacetylases. Finally, topoisomerase inhibition, previously observed in silico, was confirmed. In conclusion, structural modifications of progenitor fluoroquinolones resulted in potent anticancer derivatives possessing multiple mechanisms of action, potentially exploitable for the treatment of aggressive/resistant cancers.
PubMed: 38927932
DOI: 10.3390/cancers16122227 -
Scientific Reports Jun 2024The development of flame-retardant materials has become an important research direction. For the past dozen years, researchers have been exploring flame retardants with...
Preparation and characterization of novel flame-retardant paint of substituted cyclodiphosph(V)azane sulfonomide and their Cu(II), Cd(II) metal complexes as new additives for exterior wood coating protection.
The development of flame-retardant materials has become an important research direction. For the past dozen years, researchers have been exploring flame retardants with high flame-retardant efficiency, low toxicity, less smoke, or other excellent performance flame retardants. Therefore, this work aimed to synthesize new cyclodiphosph(V)azane derivatives and their Cu(II) and Cd(II) metal complexes and investigated their potential applications as high flame-retardant efficiency. Various techniques were used to characterize the prepared ligand HL and its metal complexes, including elemental analyses, mass spectra, conductivity measurements, electronic spectral data UV-vis, FT-IR, H,C-NMR, TGA, XRD, and molecular docking experiments studies were M. tuberculosis receptors (PDB ID: 5UHF) and the crystal structure of human topoisomerase II alpha (PDB ID: 4FM9). Wood-based paint was physically mixed with the ligand HL and its metal complexes. The obtained results of mechanical characteristics of the dried paint layers were noticed to improve, such as gloss value, which ranged from 85 to 95, hardness 1.5-2.5 kg, adhesion 4B to 5B, and impact resistance, which improved from 1.3 to 2.5 J. Moreover, the obtained results of flame-retardant properties showed a significant retardant impact compared to the blank sample, such as ignitability, which includes the heat flux which increased from 10 to 25 kW/m, and ignition time, ranging from 550 to 1200 s, respectively, and limiting oxygen index (LOI) (%) which has been increased from 21 to 130 compared with the plywood sample and sample blank. The ordering activity of the observed results was noticed that coated sample based on Cd(II) metal complexes > coated sample based on Cu(II) metal complexes of Cyclophosphazene ligand > coated sample based on phosphazene ligand HL > coated sample without additives > uncoated sample. This efficiency may be attributed to (1) the HL is an organophosphorus compound, which contains P, N, Cl, and aromatic six- and five-member ring, (2) Cu(II) and Cd(II) metal complexes characterized by high thermal stability, good stability, excellent performance flame retardants, and wide application.
PubMed: 38914569
DOI: 10.1038/s41598-024-64065-w -
Heliyon Jun 2024This research examines the function of protein associated with topoisomerase II homolog 1 () in nasal-type natural killer/T-cell lymphoma (NKTCL) and head and neck...
This research examines the function of protein associated with topoisomerase II homolog 1 () in nasal-type natural killer/T-cell lymphoma (NKTCL) and head and neck squamous cell carcinoma (HNSCC). We analyzed bulk RNA-seq data from NKTCL, nasal polyps, and normal nasal mucosa, identifying 439 differentially expressed genes. Machine learning algorithms highlighted as a hub gene. exhibited significant upregulation in NKTCL and HNSCC tumor samples in comparison to normal tissues, showing high diagnostic accuracy (AUC = 1.000) for NKTCL. Further analysis of local hospital data identified as an independent prognostic risk factor for NKTCL. Data analysis of TCGA and GEO datasets revealed that high expression correlated with poorer prognosis in HNSCC patients ( < 0.05). We also constructed a -based nomogram, which emerged as an independent prognostic predictor for HNSCC after addressing missing values. Additionally, we found a strong correlation between and various immune cell infiltrates (e.g., activated.CD4 T cell), and a significant association with the expression of 37 immune checkpoints genes (e.g., , ) and 20 N6-methyladenosine-related genes (e.g., , ) (all < 0.05). Both TCIA and TIDE algorithms suggested that could potentially predict immunotherapy efficacy ( < 0.05). Cellular experiments demonstrated that transfection with a silencing plasmid of significantly inhibited the malignant behaviors of SNK6 and FaDu cell lines( < 0.05). In conclusion, our findings suggest that may serve as a valuable prognostic and predictive biomarker in NKTCL and HNSCC, highlighting its significant role in these cancers.
PubMed: 38912458
DOI: 10.1016/j.heliyon.2024.e32158 -
International Journal of Molecular... May 2024DNA Topoisomerase IIα (Top2A) is a nuclear enzyme that is a cancer drug target, and there is interest in identifying novel sites on the enzyme to inhibit cancer cells...
DNA Topoisomerase IIα (Top2A) is a nuclear enzyme that is a cancer drug target, and there is interest in identifying novel sites on the enzyme to inhibit cancer cells more selectively and to reduce off-target toxicity. The C-terminal domain (CTD) is one potential target, but it is an intrinsically disordered domain, which prevents structural analysis. Therefore, we set out to analyze the sequence of Top2A from 105 species using bioinformatic analysis, including the PSICalc algorithm, Shannon entropy analysis, and other approaches. Our results demonstrate that large (10th-order) interdependent clusters are found including non-proximal positions across the major domains of Top2A. Further, CTD-specific clusters of the third, fourth, and fifth order, including positions that had been previously analyzed via mutation and biochemical assays, were identified. Some of these clusters coincided with positions that, when mutated, either increased or decreased relaxation activity. Finally, sites of low Shannon entropy (i.e., low variation in amino acids at a given site) were identified and mapped as key positions in the CTD. Included in the low-entropy sites are phosphorylation sites and charged positions. Together, these results help to build a clearer picture of the critical positions in the CTD and provide potential sites/regions for further analysis.
Topics: DNA Topoisomerases, Type II; Computational Biology; Humans; Protein Domains; Entropy; Amino Acid Sequence; Poly-ADP-Ribose Binding Proteins; Phosphorylation
PubMed: 38891861
DOI: 10.3390/ijms25115674 -
Nature Communications Jun 2024RNA Polymerase (RNAP) II transcription on non-coding repetitive satellite DNAs plays an important role in chromosome segregation, but a little is known about the...
RNA Polymerase (RNAP) II transcription on non-coding repetitive satellite DNAs plays an important role in chromosome segregation, but a little is known about the regulation of satellite transcription. We here show that Topoisomerase I (TopI), not TopII, promotes the transcription of α-satellite DNAs, the main type of satellite DNAs on human centromeres. Mechanistically, TopI localizes to centromeres, binds RNAP II and facilitates RNAP II elongation. Interestingly, in response to DNA double-stranded breaks (DSBs), α-satellite transcription is dramatically stimulated in a DNA damage checkpoint-independent but TopI-dependent manner, and these DSB-induced α-satellite RNAs form into strong speckles in the nucleus. Remarkably, TopI-dependent satellite transcription also exists in mouse 3T3 and Drosophila S2 cells and in Drosophila larval imaginal wing discs and tumor tissues. Altogether, our findings herein reveal an evolutionally conserved mechanism with TopI as a key player for the regulation of satellite transcription at both cellular and animal levels.
Topics: Animals; DNA, Satellite; Humans; Centromere; Mice; DNA Topoisomerases, Type I; Transcription, Genetic; RNA Polymerase II; DNA Breaks, Double-Stranded; Drosophila; Drosophila melanogaster; Evolution, Molecular
PubMed: 38886382
DOI: 10.1038/s41467-024-49567-5 -
ELife Jun 2024DNA gyrase, a ubiquitous bacterial enzyme, is a type IIA topoisomerase formed by heterotetramerisation of 2 GyrA subunits and 2 GyrB subunits, to form the active...
DNA gyrase, a ubiquitous bacterial enzyme, is a type IIA topoisomerase formed by heterotetramerisation of 2 GyrA subunits and 2 GyrB subunits, to form the active complex. DNA gyrase can loop DNA around the C-terminal domains (CTDs) of GyrA and pass one DNA duplex through a transient double-strand break (DSB) established in another duplex. This results in the conversion from a positive (+1) to a negative (-1) supercoil, thereby introducing negative supercoiling into the bacterial genome by steps of 2, an activity essential for DNA replication and transcription. The strong protein interface in the GyrA dimer must be broken to allow passage of the transported DNA segment and it is generally assumed that the interface is usually stable and only opens when DNA is transported, to prevent the introduction of deleterious DSBs in the genome. In this paper, we show that DNA gyrase can exchange its DNA-cleaving interfaces between two active heterotetramers. This so-called interface 'swapping' (IS) can occur within a few minutes in solution. We also show that bending of DNA by gyrase is essential for cleavage but not for DNA binding per se and favors IS. Interface swapping is also favored by DNA wrapping and an excess of GyrB. We suggest that proximity, promoted by GyrB oligomerization and binding and wrapping along a length of DNA, between two heterotetramers favors rapid interface swapping. This swapping does not require ATP, occurs in the presence of fluoroquinolones, and raises the possibility of non-homologous recombination solely through gyrase activity. The ability of gyrase to undergo interface swapping explains how gyrase heterodimers, containing a single active-site tyrosine, can carry out double-strand passage reactions and therefore suggests an alternative explanation to the recently proposed 'swivelling' mechanism for DNA gyrase (Gubaev et al., 2016).
Topics: DNA Gyrase; Protein Multimerization; DNA, Bacterial; Escherichia coli; DNA
PubMed: 38856655
DOI: 10.7554/eLife.86722 -
The Journal of Biological Chemistry Jun 2024Meiosis reduces ploidy through two rounds of chromosome segregation preceded by one round of DNA replication. In meiosis I, homologous chromosomes segregate while in...
Meiosis reduces ploidy through two rounds of chromosome segregation preceded by one round of DNA replication. In meiosis I, homologous chromosomes segregate while in meiosis II, sister chromatids separate from each other. Topoisomerase II (Topo II) is a conserved enzyme that alters DNA structure by introducing transient double strand breaks. During mitosis, Topo II relieves topological stress associated with unwinding DNA during replication, recombination, and sister chromatid segregation. Topo II also plays a role in maintaining mitotic chromosome structure. However, the role and regulation of Topo II during meiosis is not well defined. Previously, we found an allele of Topo II, top-2(it7), disrupts homologous chromosome segregation during meiosis I of C. elegans spermatogenesis. In a genetic screen, we identified different point mutations in 5'-tyrosyl-DNA phosphodiesterase two (Tdp2, C. elegans tdpt-1) that suppress top-2(it7) embryonic lethality. Tdp2 removes trapped Top-2-DNA complexes. The tdpt-1 suppressing mutations rescue embryonic lethality, ameliorate chromosome segregation defects, and restore TOP-2 protein levels of top-2(it7). Here, we show that both TOP-2 and TDPT-1 are expressed in germ line nuclei but occupy different compartments until late meiotic prophase. We also demonstrate that tdpt-1 suppression is due to loss of function of the protein and that the tdpt-1 mutations do not have a phenotype independent of top-2(it7) in meiosis. Lastly, we found that the tdpt-1 suppressing mutations either impair the phosphodiesterase activity, affect the stability of TDPT-1, or disrupt protein interactions. This suggests that the wild-type TDPT-1 protein is inhibiting chromosome biological functions of an impaired TOP-2 during meiosis.
PubMed: 38844130
DOI: 10.1016/j.jbc.2024.107446 -
Life Science Alliance Aug 2024RNA-binding proteins are frequently deregulated in cancer and emerge as effectors of the DNA damage response (DDR). The non-POU domain-containing octamer-binding protein...
RNA-binding proteins are frequently deregulated in cancer and emerge as effectors of the DNA damage response (DDR). The non-POU domain-containing octamer-binding protein NONO/p54 is a multifunctional RNA-binding protein that not only modulates the production and processing of mRNA, but also promotes the repair of DNA double-strand breaks (DSBs). Here, we investigate the impact of deletion in the murine KP ( , ) cell-based lung cancer model. We show that the deletion of Nono impairs the response to DNA damage induced by the topoisomerase II inhibitor etoposide or the radiomimetic drug bleomycin. Nono-deficient KP (KPN) cells display hyperactivation of DSB signalling and high levels of DSBs. The defects in the DDR are accompanied by reduced RNA polymerase II promoter occupancy, impaired nascent RNA synthesis, and attenuated induction of the DDR factor growth arrest and DNA damage-inducible beta (Gadd45b). Our data characterise Gadd45b as a putative Nono-dependent effector of the DDR and suggest that Nono mediates a genome-protective crosstalk of the DDR with the RNA metabolism via induction of Gadd45b.
Topics: Animals; DNA Repair; Mice; RNA-Binding Proteins; DNA Damage; DNA Breaks, Double-Stranded; Antigens, Differentiation; Bleomycin; DNA-Binding Proteins; Etoposide; Signal Transduction; Lung Neoplasms; Tumor Suppressor Protein p53; Cell Line, Tumor; RNA Polymerase II; Humans; GADD45 Proteins
PubMed: 38843934
DOI: 10.26508/lsa.202302555 -
PloS One 2024Signal regulatory protein alpha (SIRPα) is an immune inhibitory receptor on myeloid cells including macrophages and dendritic cells, which binds to CD47, a ubiquitous...
Signal regulatory protein alpha (SIRPα) is an immune inhibitory receptor on myeloid cells including macrophages and dendritic cells, which binds to CD47, a ubiquitous self-associated molecule. SIRPα-CD47 interaction is exploited by cancer cells to suppress anti-tumor activity of myeloid cells, therefore emerging as a novel immune checkpoint for cancer immunotherapy. In blood cancer, several SIRPα-CD47 blockers have shown encouraging monotherapy activity. However, the anti-tumor activity of SIRPα-CD47 blockers in solid tumors seems limited, suggesting the need for combination therapies to fully exploit the myeloid immune checkpoint in solid tumors. Here we tested whether combination of SIRPα-CD47 blocker with antibody-drug conjugate bearing a topoisomerase I inhibitor DXd (DXd-ADC) would enhance anti-tumor activity in solid tumors. To this end, DS-1103a, a newly developed anti-human SIRPα antibody (Ab), was assessed for the potential combination benefit with datopotamab deruxtecan (Dato-DXd) and trastuzumab deruxtecan (T-DXd), DXd-ADCs targeting human trophoblast cell-surface antigen 2 and human epidermal growth factor receptor 2, respectively. DS-1103a inhibited SIRPα-CD47 interaction and enhanced antibody-dependent cellular phagocytosis of Dato-DXd and T-DXd against human cancer cells. In a whole cancer cell vaccination model, vaccination with DXd-treated cancer cells led to activation of tumor-specific T cells when combined with an anti-mouse SIRPα (anti-mSIRPα) Ab, implying the benefit of combining DXd-ADCs with anti-SIRPα Ab on anti-tumor immunity. Furthermore, in syngeneic mouse models, both Dato-DXd and T-DXd combination with anti-mSIRPα Ab showed stronger anti-tumor activity over the monotherapies. Taken together, this study provides a preclinical rationale of novel therapies for solid tumors combining SIRPα-CD47 blockers with DXd-ADCs.
Topics: CD47 Antigen; Animals; Receptors, Immunologic; Humans; Mice; Immunoconjugates; Antigens, Differentiation; Cell Line, Tumor; Female; Trastuzumab; Topoisomerase I Inhibitors; Immunotherapy; Mice, Inbred BALB C
PubMed: 38843278
DOI: 10.1371/journal.pone.0304985 -
Nature Communications May 2024Type II topoisomerases are ubiquitous enzymes that play a pivotal role in modulating the topological configuration of double-stranded DNA. These topoisomerases are...
Type II topoisomerases are ubiquitous enzymes that play a pivotal role in modulating the topological configuration of double-stranded DNA. These topoisomerases are required for DNA metabolism and have been extensively studied in both prokaryotic and eukaryotic organisms. However, our understanding of virus-encoded type II topoisomerases remains limited. One intriguing example is the African swine fever virus, which stands as the sole mammalian-infecting virus encoding a type II topoisomerase. In this work, we use several approaches including cryo-EM, X-ray crystallography, and biochemical assays to investigate the structure and function of the African swine fever virus type II topoisomerase, pP1192R. We determine the structures of pP1192R in different conformational states and confirm its enzymatic activity in vitro. Collectively, our results illustrate the basic mechanisms of viral type II topoisomerases, increasing our understanding of these enzymes and presenting a potential avenue for intervention strategies to mitigate the impact of the African swine fever virus.
Topics: African Swine Fever Virus; DNA Topoisomerases, Type II; Animals; Crystallography, X-Ray; Cryoelectron Microscopy; Swine; Viral Proteins; Models, Molecular; Protein Conformation; African Swine Fever
PubMed: 38816407
DOI: 10.1038/s41467-024-49047-w