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Journal of Enzyme Inhibition and... Dec 2023In this research, two novel series of dibenzo[]azepines (14 candidates) were designed and synthesised based on the rigidification principle and following the reported...
Design and synthesis of novel rigid dibenzo[]azepines through ring closure technique as promising anticancer candidates against leukaemia and acting as selective topoisomerase II inhibitors and DNA intercalators.
In this research, two novel series of dibenzo[]azepines (14 candidates) were designed and synthesised based on the rigidification principle and following the reported doxorubicin's pharmacophoric features. The anti-proliferative activity was evaluated at the NCI against a panel of 60 cancer cell lines. Further, the promising candidates () were evaluated for their ability to inhibit topoisomerase II, where was noticed to be the most active congener. Moreover, its cytotoxicity was evaluated against leukaemia SR cells. Also, arrested the cell cycle at the G1 phase and increased the apoptosis ratio by 37.34%. Furthermore, studies of showed the inhibition of tumour proliferation and the decrease in its volume. Histopathology and liver enzymes were examined as well. Besides, molecular docking, physicochemical, and pharmacokinetic properties were carried out. Finally, a SAR study was discussed to open the gate for further optimisation of the most promising candidate ().HighlightsTwo novel series of dibenzo[]azepines were designed and synthesised based on the rigidification principle in drug design.The anti-proliferative activity was evaluated at the NCI against a panel of 60 cancer cell lines. was the most active anti-topo II congener (IC = 6.36 ± 0.36 µM). was evaluated against leukaemia SR cells and its cytotoxic effect was confirmed (IC = 13.05 ± 0.62 µM). studies of significantly inhibited tumour proliferation by 62.7% and decreased tumour volume to 30.1 mm compared to doxorubicin treatment.
Topics: Humans; Topoisomerase II Inhibitors; Structure-Activity Relationship; Intercalating Agents; Molecular Docking Simulation; Cell Line, Tumor; Azepines; Antineoplastic Agents; Doxorubicin; Leukemia; DNA; Cell Proliferation; Molecular Structure; Drug Screening Assays, Antitumor; DNA Topoisomerases, Type II
PubMed: 36629421
DOI: 10.1080/14756366.2022.2157825 -
Human Genetics Sep 2023Mutations in TDP2, encoding tyrosyl-DNA phosphodiesterase 2, have been associated with a syndromal form of autosomal recessive spinocerebellar ataxia, type 23 (SCAR23)....
Mutations in TDP2, encoding tyrosyl-DNA phosphodiesterase 2, have been associated with a syndromal form of autosomal recessive spinocerebellar ataxia, type 23 (SCAR23). This is a very rare and progressive neurodegenerative disorder described in only nine patients to date, and caused by splice site or nonsense mutations that result in greatly reduced or absent TDP2 protein. TDP2 is required for the rapid repair of DNA double-strand breaks induced by abortive DNA topoisomerase II (TOP2) activity, important for genetic stability in post-mitotic cells such as neurons. Here, we describe a sibship that is homozygous for the first TDP2 missense mutation (p.Glu152Lys) and which presents with clinical features overlapping both SCAR23 and Fanconi anemia (FA). We show that in contrast to previously reported SCAR23 patients, fibroblasts derived from the current patient retain significant levels of TDP2 protein. However, this protein is catalytically inactive, resulting in reduced rates of repair of TOP2-induced DNA double-strand breaks and cellular hypersensitivity to the TOP2 poison, etoposide. The TDP2-mutated patient-derived fibroblasts do not display increased chromosome breakage following treatment with DNA crosslinking agents, but both TDP2-mutated and FA cells exhibit increased chromosome breakage in response to etoposide. This suggests that the FA pathway is required in response to TOP2-induced DNA lesions, providing a possible explanation for the clinical overlap between FA and the current TDP2-mutated patients. When reviewing the relatively small number of patients with SCAR23 that have been reported, it is clear that the phenotype of such patients can extend beyond neurological features, indicating that the TDP2 protein influences not only neural homeostasis but also other tissues as well.
Topics: Humans; DNA-Binding Proteins; Etoposide; Fanconi Anemia; Chromosome Breakage; Siblings; Mutation, Missense; Phosphoric Diester Hydrolases; DNA Topoisomerases, Type II; DNA
PubMed: 37558815
DOI: 10.1007/s00439-023-02589-3 -
The Journal of Cell Biology Nov 2023In response to chromatin bridges, the abscission checkpoint delays completion of cytokinesis to prevent chromosome breakage or tetraploidization. Here, we show that...
In response to chromatin bridges, the abscission checkpoint delays completion of cytokinesis to prevent chromosome breakage or tetraploidization. Here, we show that spontaneous or replication stress-induced chromatin bridges exhibit "knots" of catenated and overtwisted DNA next to the midbody. Topoisomerase IIα (Top2α) forms abortive Top2-DNA cleavage complexes (Top2ccs) on DNA knots; furthermore, impaired Top2α-DNA cleavage activity correlates with chromatin bridge breakage in cytokinesis. Proteasomal degradation of Top2ccs is required for Rad17 localization to Top2-generated double-strand DNA ends on DNA knots; in turn, Rad17 promotes local recruitment of the MRN complex and downstream ATM-Chk2-INCENP signaling to delay abscission and prevent chromatin breakage. In contrast, dicentric chromosomes that do not exhibit knotted DNA fail to activate the abscission checkpoint in human cells. These findings are the first to describe a mechanism by which the abscission checkpoint detects chromatin bridges, through generation of abortive Top2ccs on DNA knots, to preserve genome integrity.
Topics: Humans; Cell Cycle Proteins; Cell Nucleus; Chromatin; Chromosome Breakage; Cytokinesis; DNA; Cell Cycle Checkpoints; DNA Topoisomerases, Type II
PubMed: 37638884
DOI: 10.1083/jcb.202303123 -
ACS Infectious Diseases Apr 2024Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone... (Review)
Review
Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone antibacterials. These drugs act by stabilizing gyrase/topoisomerase IV-generated DNA strand breaks and by robbing the cell of the catalytic activities of these essential enzymes. Since their clinical approval in the mid-1980s, fluoroquinolones have been used to treat a broad spectrum of infectious diseases and are listed among the five "highest priority" critically important antimicrobial classes by the World Health Organization. Unfortunately, the widespread use of fluoroquinolones has been accompanied by a rise in target-mediated resistance caused by specific mutations in gyrase and topoisomerase IV, which has curtailed the medical efficacy of this drug class. As a result, efforts are underway to identify novel antibacterials that target the bacterial type II topoisomerases. Several new classes of gyrase/topoisomerase IV-targeted antibacterials have emerged, including novel bacterial topoisomerase inhibitors, gyrase inhibitors, triazaacenaphthylenes, spiropyrimidinetriones, and thiophenes. Phase III clinical trials that utilized two members of these classes, gepotidacin (triazaacenaphthylene) and zoliflodacin (spiropyrimidinetrione), have been completed with positive outcomes, underscoring the potential of these compounds to become the first new classes of antibacterials introduced into the clinic in decades. Because gyrase and topoisomerase IV are validated targets for established and emerging antibacterials, this review will describe the catalytic mechanism and cellular activities of the bacterial type II topoisomerases, their interactions with fluoroquinolones, the mechanism of target-mediated fluoroquinolone resistance, and the actions of novel antibacterials against wild-type and fluoroquinolone-resistant gyrase and topoisomerase IV.
Topics: DNA Topoisomerase IV; Fluoroquinolones; DNA Gyrase; Topoisomerase II Inhibitors; Anti-Bacterial Agents; DNA; Mycobacterium tuberculosis
PubMed: 38564341
DOI: 10.1021/acsinfecdis.4c00128 -
Journal of Enzyme Inhibition and... Dec 2023Novel series of aminopyrimidines bearing a biologically active cyclohexenone and oxo-selaneylidene moiety , besides selenadiazolopyrimidines ( and ), were synthesised...
Novel series of aminopyrimidines bearing a biologically active cyclohexenone and oxo-selaneylidene moiety , besides selenadiazolopyrimidines ( and ), were synthesised using 5,6-diaminouracils as starting materials. Compound exhibited strong anti-proliferative activity against three cell lines: HepG-2 (IC 14.31 ± 0.83 µM), A-549 (IC 30.74 ± 0.76 µM), and MCF-7 (IC 27.14 ± 1.91 µM). Also, it was four times more selectively cytotoxic against WI-38 cell lines than doxorubicin. Furthermore, Topoisomerase II (IC 4.48 ± 0.65 µM) and HSP90 (IC 1.78 ± 0.11 µM) were both strongly inhibited by . The cell cycle was halted at the G1-S phase, and total apoptotic cells were 65 times more than control Hep-G2 cells. Besides, it increased caspase-3 gene expression, triggering mitochondrial cell death. Molecular docking study indicated that it could bind to Topoisomerase II and HSP90 binding sites in an inhibitory mode. Its geometric properties were investigated using the density functional theory (DFT). Furthermore, compound demonstrated good oral bioavailability.
Topics: Pyrimidines; Topoisomerase II Inhibitors; HSP90 Heat-Shock Proteins; Hep G2 Cells; A549 Cells; MCF-7 Cells; Humans; Cell Proliferation; Gene Expression Regulation; Cell Cycle; Computer Simulation; Antineoplastic Agents
PubMed: 37036011
DOI: 10.1080/14756366.2023.2198163 -
Annals of Oncology : Official Journal... Apr 2024Sacituzumab govitecan (SG) is a Trop-2-directed antibody-drug conjugate containing cytotoxic SN-38, the active metabolite of irinotecan. SG received accelerated US Food...
TROPHY-U-01, a phase II open-label study of sacituzumab govitecan in patients with metastatic urothelial carcinoma progressing after platinum-based chemotherapy and checkpoint inhibitors: updated safety and efficacy outcomes.
BACKGROUND
Sacituzumab govitecan (SG) is a Trop-2-directed antibody-drug conjugate containing cytotoxic SN-38, the active metabolite of irinotecan. SG received accelerated US Food and Drug Administration approval for locally advanced (LA) or metastatic urothelial carcinoma (mUC) previously treated with platinum-based chemotherapy and a checkpoint inhibitor, based on cohort 1 of the TROPHY-U-01 study. Mutations in the uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene are associated with increased adverse events (AEs) with irinotecan-based therapies. Whether UGT1A1 status could impact SG toxicity and efficacy remains unclear.
PATIENTS AND METHODS
TROPHY-U-01 (NCT03547973) is a multicohort, open-label, phase II registrational study. Cohort 1 includes patients with LA or mUC who progressed after platinum- and checkpoint inhibitor-based therapies. SG was administered at 10 mg/kg intravenously on days 1 and 8 of 21-day cycles. The primary endpoint was objective response rate (ORR) per central review; secondary endpoints included progression-free survival, overall survival, and safety. Post hoc safety analyses were exploratory with descriptive statistics. Updated analyses include longer follow-up.
RESULTS
Cohort 1 included 113 patients. At a median follow-up of 10.5 months, ORR was 28% (95% CI 20.2% to 37.6%). Median progression-free survival and overall survival were 5.4 months (95% CI 3.5-6.9 months) and 10.9 months (95% CI 8.9-13.8 months), respectively. Occurrence of grade ≥3 treatment-related AEs and treatment-related discontinuation were consistent with prior reports. UGT1A1 status was wildtype (∗1|∗1) in 40%, heterozygous (∗1|∗28) in 42%, homozygous (∗28|∗28) in 12%, and missing in 6% of patients. In patients with ∗1|∗1, ∗1|∗28, and ∗28|∗28 genotypes, any grade treatment-related AEs occurred in 93%, 94%, and 100% of patients, respectively, and were managed similarly regardless of UGT1A1 status.
CONCLUSIONS
With longer follow-up, the ORR remains high in patients with heavily pretreated LA or mUC. Safety data were consistent with the known SG toxicity profile. AE incidence varied across UGT1A1 subgroups; however, discontinuation rates remained relatively low for all groups.
Topics: Humans; Irinotecan; Carcinoma, Transitional Cell; Platinum; Urinary Bladder Neoplasms; Camptothecin; Immunoconjugates; Antibodies, Monoclonal, Humanized
PubMed: 38244927
DOI: 10.1016/j.annonc.2024.01.002 -
Nature Communications Nov 2023Genome topology is tied to R-loop formation and genome stability. However, the regulatory mechanism remains to be elucidated. By establishing a system to sense the...
Genome topology is tied to R-loop formation and genome stability. However, the regulatory mechanism remains to be elucidated. By establishing a system to sense the connections between R-loops and genome topology states, we show that inhibiting DNA topoisomerase 1 (TOP1i) triggers the global increase of R-loops (called topoR-loops) and DNA damages, which are exacerbated in the DNA damage repair-compromised mutant atm. A suppressor screen identifies a mutation in POL2A, the catalytic subunit of DNA polymerase ε, rescuing the TOP1i-induced topoR-loop accumulation and genome instability in atm. Importantly we find that a highly conserved junction domain between the exonuclease and polymerase domains in POL2A is required for modulating topoR-loops near DNA replication origins and facilitating faithful DNA replication. Our results suggest that DNA replication acts in concert with genome topological states to fine-tune R-loops and thereby maintain genome integrity, revealing a likely conserved regulatory mechanism of TOP1i resistance in chemotherapy for ATM-deficient cancers.
Topics: Humans; Arabidopsis; R-Loop Structures; DNA Polymerase II; DNA Replication; Mutation; DNA Damage; Genomic Instability
PubMed: 38012183
DOI: 10.1038/s41467-023-43680-7 -
Journal of Enzyme Inhibition and... Dec 2023New thiazolopyrimidine derivatives and were synthesised. All prepared compounds were evaluated by MTT cytotoxicity assay against three human tumour cell lines....
New thiazolopyrimidine derivatives and were synthesised. All prepared compounds were evaluated by MTT cytotoxicity assay against three human tumour cell lines. Compounds and exhibited potent to strong anticancer activity that was nearly comparable or superior to Doxorubicin. Compounds exhibiting significant cytotoxicity were further selected to study their inhibitory activity on the Topo II enzyme. Compound was the most potent Topo II inhibitor with an IC value of 0.23 ± 0.01 µM, which was 1.4-fold and 3.6-fold higher than the IC values of Etoposide and Doxorubicin. Furthermore, compound showed significant cell cycle disruption and apoptosis on A549 cells compared to control cells. Molecular docking of the most active compounds illustrated proper fitting to the Topo II active site, suggesting that our designed compounds are promising candidates for the development of effective anticancer agents acting through Topo II inhibition.
Topics: Humans; Topoisomerase II Inhibitors; Molecular Structure; Structure-Activity Relationship; Molecular Docking Simulation; Pyrimidines; Antineoplastic Agents; DNA Topoisomerases, Type II; Doxorubicin; Cell Proliferation; Drug Screening Assays, Antitumor
PubMed: 36776024
DOI: 10.1080/14756366.2023.2175209 -
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 -
Mutation Research. Genetic Toxicology... 2023We tested the hypothesis that the pesticides paraoxon and glyphosate cause DNA double-strand breaks (DSB) by poisoning the enzyme Type II topoisomerase (topo II)....
We tested the hypothesis that the pesticides paraoxon and glyphosate cause DNA double-strand breaks (DSB) by poisoning the enzyme Type II topoisomerase (topo II). Peripheral lymphocytes in G0 phase, treated with the pesticides, plus or minus ICRF-187, an inhibitor of Topo II, were stimulated to proliferate; induced cytogenetic damage was measured. Micronuclei, chromatin buds, nucleoplasmic bridges, and extranuclear fragments were induced by treatments with the pesticides, irrespective of the pre-treatment with ICRF-187. These results indicate that the pesticides do not act as topo II poisons. The induction of DSB may occur by other mechanisms, such as effects on other proteins involved in recombination repair.
Topics: Dexrazoxane; Paraoxon; Topoisomerase II Inhibitors; Poisons; DNA Topoisomerases, Type II; DNA; Pesticides; Glyphosate
PubMed: 37567644
DOI: 10.1016/j.mrgentox.2023.503657