Cyanotriazoles are selective topoisomerase II poisons that rapidly cure trypanosome infections.

Millions who live in Latin America and sub-Saharan Africa are at risk of trypanosomatid infections, which cause Chagas disease and human African trypanosomiasis (HAT). Improved HAT treatments are available, but Chagas disease therapies rely on two nitroheterocycles, which suffer from lengthy drug regimens and safety concerns that cause frequent treatment discontinuation. We performed phenotypic screening against trypanosomes and identified a class of cyanotriazoles (CTs) with potent trypanocidal activity both in vitro and in mouse models of Chagas disease and HAT. Cryo-electron microscopy approaches confirmed that CT compounds acted through selective, irreversible inhibition of trypanosomal topoisomerase II by stabilizing double-stranded DNA:enzyme cleavage complexes. These findings suggest a potential approach toward successful therapeutics for the treatment of Chagas disease.

Structure-Based Screening of DNA GyraseB Inhibitors for Therapeutic Applications in Tuberculosis: a Pharmacoinformatics Study.

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (MTB) and considered as serious public health concern worldwide which kills approximately five thousand people every day. Therefore, TB drug development efforts are in gigantic need for identification of new potential chemical agents to eradicate TB from the society. The bacterial DNA gyrase B (GyrB) protein as an experimentally widely accepted effective drug target for the development of TB chemotherapeutics. In the present study, advanced pharmacoinformatics approaches were used to screen the Mcule database against the GyrB protein. Based on a number of chemometric parameters, five molecules were found to be crucial to inhibit the GyrB. A number of molecular binding interactions between the proposed inhibitors and important active site residues of GyrB were observed. The predicted drug-likeness properties of all molecules were indicated that compounds possess characteristics to be the drug-like candidates. The dynamic nature of each molecule was explored through the molecular dynamics (MD) simulation study. Various analyzing parameters from MD simulation trajectory have suggested rationality of the molecules to be potential GyrB inhibitor. Moreover, the binding free energy was calculated from the entire MD simulation trajectories highlighted greater binding free energy values for all newly identified compounds also substantiated the strong binding affection towards the GyrB in comparison to the novobiocin. Therefore, the proposed molecules might be considered as potential anti-TB chemical agents for future drug discovery purposes subjected to experimental validation. Graphical Abstract.

Anticancer potency of copper(II) complexes of thiosemicarbazones.

Being a structural and catalytic cofactor in a number of biological pathways, copper accumulates in tumors owing to selective permeability of the cancer cell membranes. Copper(II) ion forms the active centers in a large number of metalloproteins. The coordination of Schiff's base ligands to the metal ion results in the high extent of increase in anticancer activity. The copper(II) complexes can cleave DNA through oxidative and hydrolytic pathways, cell apoptosis via intrinsic reactive oxygen species (ROS) mediated mitochondrial pathway due to excessive production of ROS and hence, are found more active than Ni and Pt complexes. Flexible Cu(I/II) redox behavior helps the copper complexes to form more potent, clinically effective and less toxic copper based antiproliferative drugs of lower IC50 value and higher growth inhibitory activity. Copper(II) complexes of thiosemicarbazones of Isatin, Pyridine, Benzoyl pyridine, Diacetyl/Dimethyl glyoxal, Acetophenone/Acetoacetanalide, Thiazole/Pyrazole, Quinoline, Carboxybenzaldehyde, Cinnamaldehyde/Cuminaldehyde, Citronellal, Chromone, Pyridoxal, 8-Ethyl-2-hydroxytricyclo (7.3.1.02,7) tridecan-13-one, Acyl Diazines, Naphthalene, Proline, 5-Formyluracil, 2-Hydroxy-8-propyltricyclo (7.3.1.02,7) tridecan-13-one, 9-cis-Retinal, Curcumin, Helicin (Salicylaldehyde-ß-D-glucoside), Thiophene carboxaldehyde, Salicylaldehyde, Iminodiacetate, and 3-Formyl-4-hydroxy benzenesulfonic acid have been found to exhibit more anticancer activity toward HCT116, MCF7, A549, U937, HeLa, HepG2, SGC-7901, A2780 cell lines than that of their corresponding thiosemicarbazones and standard topoisomerase-II inhibitors.

Characterization of therapy-related acute leukemia in hereditary breast-ovarian carcinoma patients: role of BRCA1 mutation and topoisomerase II-directed therapy.

Therapy-related acute leukemias (t-ALs) represent approximately 10-20% of all acute leukemias, are frequently resistant to chemotherapy, and are associated with guarded outcomes. The national comprehensive cancer network data suggest that t-AL cases are diagnosed at increasing rates in breast cancer patients treated with chemotherapeutic agents targeting topoisomerase II. Two cases of BRCA1-mutated ovarian and breast carcinoma who developed therapy-related APL and ALL, respectively, following topoisomerase II-directed therapy were characterized. Genomic characterization of therapy-related acute promyelocytic leukemia (t-APL) revealed a unique RARA intron 2 breakpoint (Chr17: 40347487) at 3'-end of RARA corroborating breakpoint clustering in t-APL following topoisomerase II inhibition. Both cases of this series harbored germline BRCA1 mutations. The germline BRCA1 mutation in patient with t-APL was detected in exon 8 (HGVS nucleotide: c.512dupT). This mutation in t-APL is extremely rare. Interestingly, t-ALL patient in this series had a BRCA1 mutation (HGVS nucleotide: c.68_69delAG; BIC designation: 187delAG) identical to a previously reported case after the treatment of same primary disease. It is unlikely that two breast cancer patients with identical BRCA1 mutation receiving topoisomerase II-targeted agents for the primary disease developed t-AL by chance. This report highlights the development of t-AL in BRAC1-mutated hereditary breast and ovarian cancer patients and warrants further studies on functional consequences of topoisomerase inhibition in this setting.

Moxifloxacin Labeling-Based Multiphoton Microscopy of Skin Cancers in Asians.

BACKGROUND AND OBJECTIVES: Although multiphoton microscopy (MPM) can visualize both cell and extracellular matrix (ECM) structures of the skin in high-contrast without exogenous labeling, label-free MPM is usually too slow to image clinically relevant large regions. A high-speed MPM method would be beneficial for evaluating clinical skin specimens by increasing the imaging area. In this study, moxifloxacin labeling-based MPM (moxifloxacin MPM) was characterized in various human skin cancer specimens. STUDY DESIGN/MATERIALS AND METHODS: Moxifloxacin ophthalmic solution was used for cell-labeling and MPM imaging was conducted afterwards. Moxifloxacin MPM was characterized in ex vivo normal human skin and skin cancer specimens in comparison with the label-free MPM and fluorescence confocal microscopy (FCM) using acridine orange as a labeling agent. Then, moxifloxacin MPM was applied to various ex vivo human skin cancer specimens including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), dermatofibrosarcoma protuberans (DFSP). Results of moxifloxacin MPM were compared with bright-field clinical and histopathologic findings. RESULTS: Moxifloxacin MPM imaged both cells and collagen in the skin, similarly to label-free MPM, but with enhanced fluorescence intensities in cells and enhanced imaging speeds. Moxifloxacin MPM imaged cells in the skin similarly to acridine orange-based FCM. Moxifloxacin MPM of various human skin cancer specimens imaged their specific cellular features. The microscopic features detected in moxifloxacin MPM were confirmed with histological images. CONCLUSIONS: This observational pilot study demonstrated that moxifloxacin MPM could detect specific cellular features of various skin cancers in good correlation with histopathological images in Asian patients at the higher imaging speed than label-free MPM. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Pharmacophore modeling and molecular dynamics approach to identify putative DNA Gyrase B inhibitors for resistant tuberculosis.

One of the major mechanisms followed by the therapeutic agents to target the causative organism of TB, mycobacterium tuberculosis (Mtb), involves disruption of the replication cycle of the pathogen DNA. The process involves two steps that occur simultaneously, ie, breakage and reunion of DNA at gyrase A (GyrA) domain and ATP hydrolysis at gyrase B (GyrB) domain. Current therapy for multi-drug resistant TB involves FDA approved, Fluoroquinolone-based antibiotics, which act by targeting the replication process at GyrA domain. However, resistance against fluoroquinolones due to mutations in the GyrA domain has limited the use of this therapy and shifted the focus of the research community on the GyrB domain. Thus, this study involves in silico designing of chemotherapeutic agents for resistant TB by targeting GyrB domain. In the current study, a pharmacophore model for GyrB domain was generated using reported inhibitors. It was utilized as a query search against three commercial databases to identify GyrB domain inhibitors. Additionally, a qualitative Hip-Hop pharmacophore model for GyrA was also developed on the basis of some marketed fluoroquinolone-based GyrA inhibitors, to remove non-selective gyrase inhibitors obtained in virtual screening. Further, molecular dynamic simulations were carried out to determine the stability of the obtained molecules in complex with both the domains. Finally, Molecular mechanics with generalized Born and surface area solvation score was calculated to determine the binding affinity of obtained molecule with both domains to determine the selectivity of the obtained molecules that resulted in seven putative specific inhibitors of GyrB domain.

[The Efficacy of Moxifloxacin-containing Triple Therapy after Hybrid Therapy Failure in Helicobacter pylori Eradication].

BACKGROUND/AIMS: Hybrid therapy was successful in eradicating Helicobacter pylori (H. pylori) according to previous reports. However, to the best of our knowledge, there have only been a few studies evaluating the optimal choice after hybrid failure. Hence, we aimed to evaluate the efficacy of moxifloxacin-containing triple therapy after hybrid therapy failure in H. pylori eradication. METHODS: Between January 2013 and March 2016, we retrospectively reviewed patients who underwent failed hybrid therapy, as first line treatment, in eradicating H. pylori (rabeprazole and amoxicillin b.i.d for 14 days, in addition to clarithromycin and metronidazole b.i.d for final 7 days). Then, we investigated the eradication rates of moxifloxacin-containing triple therapy (rabeprazole, amoxicillin b.i.d and moxifloxacin qd) as the second line of treatment. Intention-to-treat (ITT) and per-protocol (PP) analyses were used to determine the eradication rate. We evaluated the status of H. pylori by using 13C-urea breath test 6 weeks after the final treatment. Moreover, compliance and adverse effects of each patient were analyzed. RESULTS: Among those who failed the initial hybrid therapy, 11 patients received moxifloxacin-containing triple therapy. The overall eradication rates, as determined by ITT and PP, were 72.7% (n=8/11) and 80% (n=8/10), respectively. The compliance rate was 100%, and there were no serious adverse effects. CONCLUSIONS: Moxifloxacin-containing triple therapy can be used as a second line therapy in case of hybrid therapy failure. A large scale study is necessary to confirm the findings of this study and establish clinical evidence.

Critical concepts, practice recommendations, and research perspectives of pixantrone therapy in non-Hodgkin lymphoma: a SIE, SIES, and GITMO consensus paper.

OBJECTIVES: In this paper, we present a review of critical concepts and research perspectives and produce recommendations on the optimal use of pixantrone in non-Hodgkin lymphoma (NHL) by group discussion from an expert panel appointed by the Italian Society of Hematology and the affiliate societies, Società Italiana di Ematologia Sperimentale and Gruppo Italiano Trapianto di Midollo Osseo. METHODS: Recommendations were produced using the Delphi process. Scientific evidence on pixantrone efficacy was analyzed using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology in the areas where at least one randomized trial was published. The following key issues were addressed for practical recommendations: pixantrone monotherapy in aggressive relapsed or refractory non-Hodgkin B-cell lymphomas and toxicity risk management in patients candidates to pixantrone. RESULTS AND CONCLUSIONS: After a balanced and value-oriented discussion, the panel agreed that the benefit/risk profile was in favor of pixantrone in the treatment of adult patients with multiply relapsed or refractory aggressive NHL B-cell lymphomas. Pixantrone was deemed to be contraindicated in patients with uncontrolled cardiovascular disease. Despite a low rate of cardiotoxicity of pixantrone reported in clinical trials, the panel recommended that all patients receiving pixantrone should undergo periodical cardiac monitoring.

Discovery of a novel anti-cancer agent targeting both topoisomerase I and II in hepatocellular carcinoma Hep 3B cells in vitro and in vivo: Cinnamomum verum component 2-methoxycinnamaldehyde.

Cinnamomum verum has been used as a traditional Chinese herbal medicine. We evaluated the anticancer effect of 2-methoxycinnamaldehyde (2-MCA), a constituent of the bark of the plant, in hepatocellular carcinoma Hep 3B cells. The results show that 2-MCA suppressed proliferation and induced apoptosis as indicated by an up-regulation of pro-apoptotic bax and bak genes and down-regulation of anti-apoptotic bcl-2 and bcl-XL genes, mitochondrial membrane potential loss, cytochrome c release, activation of caspase 3 and 9, increase in the DNA content in sub G1, and morphological characteristics of apoptosis. 2-MCA also induced lysosomal vacuolation with increased volume of acidic compartments (VAC), suppressions of nuclear transcription factors NF-κB, cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and both topoisomerase I and II activities in a dose-dependent manner. Further study reveals the growth-inhibitory effect of 2-MCA was also evident in a nude mice model. Taken together, the data suggest that the growth-inhibitory effect of 2-MCA against Hep 3B cells is accompanied by downregulations of NF-κB binding activity, inflammatory responses involving COX-2 and PGE2, and proliferative control involving apoptosis, both topoisomerase I and II activities, together with an upregulation of lysosomal vacuolation and VAC. Our data suggest that 2-MCA could be a potential agent for anticancer therapy.

Responding to the challenge of untreatable gonorrhea: ETX0914, a first-in-class agent with a distinct mechanism-of-action against bacterial Type II topoisomerases.

With the diminishing effectiveness of current antibacterial therapies, it is critically important to discover agents that operate by a mechanism that circumvents existing resistance. ETX0914, the first of a new class of antibacterial agent targeted for the treatment of gonorrhea, operates by a novel mode-of-inhibition against bacterial type II topoisomerases. Incorporating an oxazolidinone on the scaffold mitigated toxicological issues often seen with topoisomerase inhibitors. Organisms resistant to other topoisomerase inhibitors were not cross-resistant with ETX0914 nor were spontaneous resistant mutants to ETX0914 cross-resistant with other topoisomerase inhibitor classes, including the widely used fluoroquinolone class. Preclinical evaluation of ETX0914 pharmacokinetics and pharmacodynamics showed distribution into vascular tissues and efficacy in a murine Staphylococcus aureus infection model that served as a surrogate for predicting efficacious exposures for the treatment of Neisseria gonorrhoeae infections. A wide safety margin to the efficacious exposure in toxicological evaluations supported progression to Phase 1. Dosing ETX0914 in human volunteers showed sufficient exposure and minimal adverse effects to expect a highly efficacious anti-gonorrhea therapy.