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Biological & Pharmaceutical Bulletin Jul 2022Saikosaponin A (SSA)-a natural compound extracted from Radix bupleuri-possesses antitumor properties in several types of carcinomas. However, the role of SSA on bladder...
Saikosaponin A (SSA)-a natural compound extracted from Radix bupleuri-possesses antitumor properties in several types of carcinomas. However, the role of SSA on bladder cancer and the mechanisms remain unclear. In this study, we have described the effect of SSA on human bladder cancer cell lines T24 and 5637 in the context of the regulation of mitochondrial pathways of apoptosis. In vitro, the Cell Counting Kit-8 (CCK-8) assay and cell wound healing assays were used to determine the proliferative effect of SSA treatment. Flow cytometry and Western blotting were performed to evaluate the apoptosis and related mechanisms. To further confirm that apoptosis is mediated through Caspase activation, Hoechst 33258 fluorescence staining assay was done after cells were treated with SSA and caspase inhibitor-Z-VAD-FMK. In vivo, an orthotopic xenograft mice model was adopted to evaluate the effect of SSA. The tumors were analyzed by hematoxylin-eosin (H&E) staining, immunohistochemical analysis, and Western blotting. In vitro, the results with CCK-8 assay showed obvious SSA-induced suppression in cell growth in a dose- and time-dependent manner. Flow cytometry analysis, Hoechst 33258 fluorescence staining assay and the assessment of the changes in the B-cell lymphoma 2 (Bcl-2) family protein expression level revealed that SSA could significantly induce cell apoptosis, which was associated with apoptosis via the mitochondrial pathways. In vivo, the results revealed a reduction in cell proliferation. In conclusion, our data suggest that SSA inhibits the growth of bladder cancer cells by activating the mitochondrial apoptosis pathway and inducing cell apoptosis.
Topics: Animals; Apoptosis; Bisbenzimidazole; Carcinoma; Caspases; Cell Line, Tumor; Cell Proliferation; Humans; Mice; Oleanolic Acid; Saponins; Urinary Bladder; Urinary Bladder Neoplasms
PubMed: 35491088
DOI: 10.1248/bpb.b21-01025 -
Antimicrobial Agents and Chemotherapy May 2023Clostridioides difficile infection (CDI) causes substantial morbidity and mortality worldwide with limited antibiotic treatment options. Ridinilazole is a precision...
Clostridioides difficile infection (CDI) causes substantial morbidity and mortality worldwide with limited antibiotic treatment options. Ridinilazole is a precision bisbenzimidazole antibiotic being developed to treat CDI and reduce unacceptably high rates of infection recurrence in patients. Although in late clinical development, the precise mechanism of action by which ridinilazole elicits its bactericidal activity has remained elusive. Here, we present conclusive biochemical and structural data to demonstrate that ridinilazole has a primary DNA binding mechanism, with a co-complex structure confirming binding to the DNA minor groove. Additional RNA-seq data indicated early pleiotropic changes to transcription, with broad effects on multiple C. difficile compartments and significant effects on energy generation pathways particularly. DNA binding and genomic localization was confirmed through confocal microscopy utilizing the intrinsic fluorescence of ridinilazole upon DNA binding. As such, ridinilazole has the potential to be the first antibiotic approved with a DNA minor groove binding mechanism of action.
Topics: Humans; Anti-Bacterial Agents; Clostridioides difficile; Pyridines; Clostridium Infections
PubMed: 37093023
DOI: 10.1128/aac.01563-22 -
Bioorganic & Medicinal Chemistry Letters Oct 2013Synthesis of a novel class of compounds and their biophysical studies with TAR-RNA are presented. The synthesis of these compounds was achieved by conjugating neomycin,...
Synthesis of a novel class of compounds and their biophysical studies with TAR-RNA are presented. The synthesis of these compounds was achieved by conjugating neomycin, an aminoglycoside, with benzimidazoles modeled from a B-DNA minor groove binder, Hoechst 33258. The neomycin-benzimidazole conjugates have varying linkers that connect the benzimidazole and neomycin units. The linkers of varying length (5-23 atoms) in these conjugates contain one to three triazole units. The UV thermal denaturation experiments showed that the conjugates resulted in greater stabilization of the TAR-RNA than either neomycin or benzimidazole used in the synthesis of conjugates. These results were corroborated by the FID displacement and tat-TAR inhibition assays. The binding of ligands to the TAR-RNA is affected by the length and composition of the linker. Our results show that increasing the number of triazole groups and the linker length in these compounds have diminishing effect on the binding to TAR-RNA. Compounds that have shorter linker length and fewer triazole units in the linker displayed increased affinity towards the TAR RNA.
Topics: Benzimidazoles; Bisbenzimidazole; Circular Dichroism; HIV Long Terminal Repeat; HIV-1; Humans; Ligands; Neomycin; RNA, Viral; tat Gene Products, Human Immunodeficiency Virus
PubMed: 24012122
DOI: 10.1016/j.bmcl.2013.08.014 -
MedChemComm Aug 2015Academic drug discovery is playing an increasingly important role in the identification of new therapies for a wide range of diseases. There is no one model that... (Review)
Review
Academic drug discovery is playing an increasingly important role in the identification of new therapies for a wide range of diseases. There is no one model that guarantees success. We describe here a drug discovery story where chance, the ability to capitalise on chance, and the assembling of a range of expertise, have all played important roles in the discovery and subsequent development of an antibiotic chemotype based on the bis-benzimidazole scaffold, with potency against a number of current therapeutically challenging diseases. One compound in this class, SMT19969, has recently entered Phase 2 human clinical trials for the treatment of infections.
PubMed: 26949507
DOI: 10.1039/c5md00238a -
Bioorganic & Medicinal Chemistry Aug 2016The rise and emergence of resistance to antifungal drugs by diverse pathogenic fungal strains have resulted in an increase in demand for new antifungal agents. Various...
The rise and emergence of resistance to antifungal drugs by diverse pathogenic fungal strains have resulted in an increase in demand for new antifungal agents. Various heterocyclic scaffolds with different mechanisms of action against fungi have been investigated in the past. Herein, we report the synthesis and antifungal activities of 18 alkylated mono-, bis-, and trisbenzimidazole derivatives, their toxicities against mammalian cells, as well as their ability to induce reactive oxygen species (ROS) in yeast cells. Many of our bisbenzimidazole compounds exhibited moderate to excellent antifungal activities against all tested fungal strains, with MIC values ranging from 15.6 to 0.975μg/mL. The fungal activity profiles of our bisbenzimidazoles were found to be dependent on alkyl chain length. Our most potent compounds were found to display equal or superior antifungal activity when compared to the currently used agents amphotericin B, fluconazole, itraconazole, posaconazole, and voriconazole against many of the strains tested.
Topics: Antifungal Agents; Benzimidazoles; Carbon-13 Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Proton Magnetic Resonance Spectroscopy; Reactive Oxygen Species; Yeasts
PubMed: 27301676
DOI: 10.1016/j.bmc.2016.06.010 -
The Journal of Neuroscience : the... Feb 2011It is widely held that the spatial processing functions underlying rodent navigation are similar to those encoding human episodic memory (Doeller et al., 2010). Spatial...
It is widely held that the spatial processing functions underlying rodent navigation are similar to those encoding human episodic memory (Doeller et al., 2010). Spatial and nonspatial information are provided by all senses including vision. It has been suggested that visual inputs are fed to the navigational network in cortex and hippocampus through dorsal and ventral intracortical streams (Whitlock et al., 2008), but this has not been shown directly in rodents. We have used cytoarchitectonic and chemoarchitectonic markers, topographic mapping of receptive fields, and pathway tracing to determine in mouse visual cortex whether the lateromedial field (LM) and the anterolateral field (AL), which are the principal targets of primary visual cortex (V1) (Wang and Burkhalter, 2007) specialized for processing nonspatial and spatial visual information (Gao et al., 2006), are distinct areas with diverse connections. We have found that the LM/AL border coincides with a change in type 2 muscarinic acetylcholine receptor expression in layer 4 and with the representation of the lower visual field periphery. Our quantitative analyses also show that LM strongly projects to temporal cortex as well as the lateral entorhinal cortex, which has weak spatial selectivity (Hargreaves et al., 2005). In contrast, AL has stronger connections with posterior parietal cortex, motor cortex, and the spatially selective medial entorhinal cortex (Haftig et al., 2005). These results support the notion that LM and AL are architecturally, topographically, and connectionally distinct areas of extrastriate visual cortex and that they are gateways for ventral and dorsal streams.
Topics: Animals; Bisbenzimidazole; Entorhinal Cortex; Female; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Microinjections; Motor Cortex; Neural Pathways; Parietal Lobe; Receptor, Muscarinic M2; Temporal Lobe; Visual Cortex
PubMed: 21289200
DOI: 10.1523/JNEUROSCI.3488-10.2011 -
Genetics Dec 1988Primary spermatocyte nuclei of fixed testes of Drosophila melanogaster exhibit three large clusters of thread-like structures, each consisting of two long, continuous,...
Primary spermatocyte nuclei of fixed testes of Drosophila melanogaster exhibit three large clusters of thread-like structures, each consisting of two long, continuous, loop-shaped filaments. No comparable intranuclear structures are observed in spermatogonia, secondary spermatocytes or spermatids. The threads begin to form in young spermatocytes, grow throughout spermatocyte development, reach their maximum size in mature spermatocytes and disintegrate prior to meiotic metaphase I. The presence of each cluster of threads depends upon the presence of a specific region of the Y chromosome; when this region is deleted the cluster is absent, and when it is duplicated the cluster is also duplicated. Together these observations strongly suggest that these structures represent giant Y chromosome lampbrush-like loops analogous to those described in Drosophila hydei. Two antibodies, one polyclonal and one monoclonal, differentially react with the three loops of D. melanogaster. Moreover, two of these loops are specifically stained by Giemsa at pH 10. By indirect immunofluorescence with these antibodies followed by Giemsa staining, each loop can be unambiguously identified and its presence and normality readily assessed. This enabled us to perform fine mapping experiments to determine the relationships between the Y chromosome fertility factors and the loops. The loop-forming sites map within the kl-5, kl-3 and ks-1 fertility factors. Regions h3 and h21 of the Y chromosome correspond to the loop-forming sites of kl-5 and ks-1, respectively. Each of these regions contains about 1300 kb of DNA and spans about one-third of its locus. The loop-forming site of the kl-3 locus is coextensive with region h7-h9 which contains about 4300 kb of DNA and corresponds to the minimum physical size of this locus. These data suggest that each loop is an integral part of a different fertility factor, representing the cytological manifestation of its activity in primary spermatocytes. The kl-2, kl-1 and ks-2 fertility regions do not produce any visible intranuclear structure and do not affect the kl-5, kl-3 and ks-1 loops. Thus, these loci may either not form loops at all or produce loop-like structures that we are unable to see because they are physically minute, destroyed by our fixation procedure, or both.
Topics: Animals; Antibodies, Monoclonal; Azure Stains; Bisbenzimidazole; Chromosome Mapping; Crosses, Genetic; DNA; Dansyl Compounds; Drosophila melanogaster; Fertility; Fluorescent Antibody Technique; Male; Microscopy, Electron; Microscopy, Phase-Contrast; Rosaniline Dyes; Spermatocytes; Staining and Labeling; Y Chromosome
PubMed: 2465201
DOI: 10.1093/genetics/120.4.1015 -
European Journal of Inorganic Chemistry Apr 2013A triptycene-based bis(benzimidazole) ester ligand, , was designed to enhance the electron donating ability of the heterocyclic nitrogen atoms relative to those of the...
A triptycene-based bis(benzimidazole) ester ligand, , was designed to enhance the electron donating ability of the heterocyclic nitrogen atoms relative to those of the first generation bis(benzoxazole) analogs, and . A convergent synthesis of was designed and executed. Three-component titration experiments using UV-visible spectroscopy revealed that the desired diiron(II) complex could be obtained with a 1:2:1 ratio of :Fe(OTf)(MeCN):external carboxylate reactants. X-ray crystallographic studies of two diiron complexes derived in this manner from revealed their formulas to be [Fe(μ-OH)(μ-OCR)(OTf)], where R = 2,6-bis(-tolyl)benzoate () or triphenylacetate (). The structures are similar to that of a diiron complex derived from , [Fe(μ-OH)(μ-OCAr)(OTf)] () with a notable difference being that, in and , the geometry at iron more closely resembles square-pyramidal than trigonal-bipyramidal. Mössbauer spectroscopic analyses of and indicate the presence of high-spin diiron(II) cores. These results demonstrate the importance of substituting benzimidazole for benzoxazole for assembling biomimetic diiron complexes with syn disposition of two -donor ligands, as found in O-activating carboxylate-bridged diiron centers in biology.
PubMed: 23585728
DOI: 10.1002/ejic.201201387 -
Oxidative Medicine and Cellular... 2016This study demonstrated that glycyrrhizate (GAS) could protect HEPG2 cells against damage and apoptosis induced by HO (1600 M, 4 h). Cell viability assay revealed...
This study demonstrated that glycyrrhizate (GAS) could protect HEPG2 cells against damage and apoptosis induced by HO (1600 M, 4 h). Cell viability assay revealed that GAS was noncytotoxity at concentration 125 g/mL, and GAS (5 g/mL, 25 g/mL, and 125 g/mL) protected HepG2 cells against HO-induced cytotoxicity. HO induced the HepG2 cells apoptosis, obvious morphologic changes were observed after Hochest 33258 staining, and more apoptotic cells were counted in flow cytometry assay compared to that of the natural group. Pretreatment GAS (5 g/mL, 25 g/mL, and 125 g/mL) prior to HO reverses the morphologic changes and reduced the apoptotic cells in HepG2 cells. GAS reduced the release of MDA, increased the activities of superoxide dismutase, and diminished the release of ALT and AST during oxidative stress in HepG2 cells. After Elisa kit detecting, GAS inhibited the caspase activity induced by HO, GAS decreased the level of caspase-3 and caspase-9 from mitochondria in dose-dependent manner. Western blot results showed that pretreatment GAS upregulated the expression of Bcl-2 and decreased the expression of Bax. These results reveal that GAS has the cytoprotection in HepG2 cells during ROS exposure by inhibiting the caspase activity in the mitochondria and influencing apoptogenic factors of the expression of Bax and Bcl-2.
Topics: Alanine Transaminase; Apoptosis; Aspartate Aminotransferases; Bisbenzimidazole; Caspases; Enzyme Activation; Glycyrrhizic Acid; Hep G2 Cells; Humans; Hydrogen Peroxide; Lipid Peroxidation; Malondialdehyde; Staining and Labeling; Superoxide Dismutase; bcl-2-Associated X Protein
PubMed: 27891207
DOI: 10.1155/2016/6849758 -
RSC Advances Jan 2021A series of squaramido-tethered bisbenzimidazoles were synthesized from the reaction of diethyl squarate with substituted 2-aminomethylbenzimidazoles. These conjugates...
A series of squaramido-tethered bisbenzimidazoles were synthesized from the reaction of diethyl squarate with substituted 2-aminomethylbenzimidazoles. These conjugates exhibit moderate binding affinity toward chloride anions. They are able to facilitate the transmembrane transport of chloride anions most probably an anion exchange process, and tend to be more active at acidic pH than at physiological pH. The viability of these conjugates toward four selected solid tumor cell lines was evaluated using an MTT assay and the results suggest that some of these conjugates exhibit moderate cytotoxicity probably in an apoptotic fashion.
PubMed: 35424339
DOI: 10.1039/d0ra10189c