-
Anticancer Research Mar 2023Cachexia - a wasting disorder of adipose and skeletal muscle tissue - is the most common driver of poor prognosis in patients with advanced lung cancer. Parathyroid...
BACKGROUND/AIM
Cachexia - a wasting disorder of adipose and skeletal muscle tissue - is the most common driver of poor prognosis in patients with advanced lung cancer. Parathyroid hormone-like hormone (PTHLH) is potentially a critical factor in cancer-associated cachexia. We previously showed that streptonigrin - an aminoquinone with antitumor effects - inhibited the interaction between TCF4 and TWIST1. This study aimed to determine the anti-cachectic performance of streptonigrin in lung cancer.
MATERIALS AND METHODS
We assessed the effect of streptonigrin on the interaction of TCF4 and TWIST1 using co-immunoprecipitation and a mammalian-two hybrid luciferase assay, which was confirmed by an in vitro GST pull-down assay using recombinant bHLH domain-containing TCF4 and TWIST1. We assessed the anti-cachectic effect of streptonigrin in vivo using an LLC1 cell-induced tumour-bearing mouse model. Changes in the degree of skeletal muscle and adipose tissue wasting were determined by measuring the weights of gastrocnemius and epidydimal white adipose tissue.
RESULTS
Streptonigrin was found to inhibit the interaction of TCF4 with TWIST1 in a dose-dependent manner. The in vitro GST pull-down assay revealed that streptonigrin directly inhibited the interaction between TCF4 and TWIST1. The expression of PTHLH mRNA, which is transcriptionally regulated by the TCF4/TWIST1 complex in response to TGF-β1 signalling, was decreased in streptonigrin-treated lung cancer cells. Streptonigrin significantly decreased the expression of proteolysis-related genes in skeletal muscle and browning-related genes in white adipose tissues of LLC1-induced tumour-bearing mice.
CONCLUSION
Streptonigrin exerts potent therapeutic effects on lung cancer-induced cachexia by suppressing TCF4/TWIST1-mediated PTHLH expression.
Topics: Animals; Mice; Adipose Tissue; Adiposity; Cachexia; Lung Neoplasms; Mammals; Streptonigrin
PubMed: 36854496
DOI: 10.21873/anticanres.16260 -
ACS Chemical Biology Dec 2022β-Carboline (βC) alkaloids constitute a large family of indole alkaloids that exhibit diverse pharmacological properties, such as antitumor, antiviral, antiparasitic,...
β-Carboline (βC) alkaloids constitute a large family of indole alkaloids that exhibit diverse pharmacological properties, such as antitumor, antiviral, antiparasitic, and antimicrobial activities. Here, we report that a flavoprotein StnP2 catalyzes the dehydrogenation at C1-N2 of a tetrahydro-β-carboline (THβC) generating a 3,4-dihydro-β-carboline (DHβC), and the DHβC subsequently undergoes a spontaneous dehydrogenation to βC formation involved in the biosynthesis of the antitumor agent streptonigrin. Biochemical characterization showed that StnP2 catalyzed the highly regio- and stereo-selective dehydrogenation, and StnP2 exhibits promiscuity toward different THβCs. This study provides an alternative kind of enzyme catalyzing the biosynthesis of βC alkaloids and enhances the importance of flavoproteins.
Topics: Streptonigrin; Flavoproteins; Carbolines; Alkaloids; Indole Alkaloids
PubMed: 36409520
DOI: 10.1021/acschembio.2c00704 -
Angewandte Chemie (International Ed. in... Jan 2023We report that axially chiral biaryl boronic esters can be generated with control of atroposelectivity by a Binol-mediated dynamic thermodynamic resolution process....
We report that axially chiral biaryl boronic esters can be generated with control of atroposelectivity by a Binol-mediated dynamic thermodynamic resolution process. These intermediates can be progressed to enantioenriched products through stereoretentive functionalization of the carbon-boron bond. Finally, we have exploited this method in the first highly stereoselective total synthesis of P-streptonigrin.
PubMed: 36377668
DOI: 10.1002/anie.202213692 -
Molecules (Basel, Switzerland) Sep 2022Hybrids 1,4-quinone with quinoline were obtained by connecting two active structures through an oxygen atom. This strategy allows to obtain new compounds with a high...
Hybrids 1,4-quinone with quinoline were obtained by connecting two active structures through an oxygen atom. This strategy allows to obtain new compounds with a high biological activity and suitable bioavailability. Newly synthesized compounds were characterized by various spectroscopic methods. The enzymatic assay used showed that these compounds were a suitable DT-diaphorase (NQO1) substrates as evidenced by increasing enzymatic conversion rates relative to that of streptonigrin. Hybrids were tested in vitro against a panel of human cell lines including melanoma, breast, and lung cancers. They showed also a high cytotoxic activity depending on the type of 1,4-quinone moiety and the applied tumor cell lines. It was found that cytotoxic activity of the studied hybrids was increasing against the cell lines with higher NQO1 protein level, such as breast (MCF-7 and T47D) and lung (A549) cancers. Selected hybrids were tested for the transcriptional activity of the gene encoding a proliferation marker (H3 histone), cell cycle regulators (p53 and p21) and the apoptosis pathway (BCL-2 and BAX). The molecular docking was used to examine the probable interaction between the hybrids and NQO1 protein.
Topics: Antineoplastic Agents; Apoptosis; Benzoquinones; Cell Line, Tumor; Drug Screening Assays, Antitumor; Histones; Humans; Hydroxyquinolines; Molecular Docking Simulation; NAD(P)H Dehydrogenase (Quinone); Oxygen; Quinolines; Quinones; Streptonigrin; Tumor Suppressor Protein p53; bcl-2-Associated X Protein
PubMed: 36234741
DOI: 10.3390/molecules27196206 -
PLoS Pathogens Jun 2022The Neisseria gonorrhoeae Type IV pilus is a multifunctional, dynamic fiber involved in host cell attachment, DNA transformation, and twitching motility. We previously...
The Neisseria gonorrhoeae Type IV pilus is a multifunctional, dynamic fiber involved in host cell attachment, DNA transformation, and twitching motility. We previously reported that the N. gonorrhoeae pilus is also required for resistance against hydrogen peroxide-, antimicrobial peptide LL-37-, and non-oxidative, neutrophil-mediated killing. We tested whether the hydrogen peroxide, LL-37, and neutrophil hypersensitivity phenotypes in non-piliated N. gonorrhoeae could be due to elevated iron levels. Iron chelation in the growth medium rescued a nonpiliated pilE mutant from both hydrogen peroxide- and antimicrobial peptide LL-37-mediated killing, suggesting these phenotypes are related to iron availability. We used the antibiotic streptonigrin, which depends on free cytoplasmic iron and oxidation to kill bacteria, to determine whether piliation affected intracellular iron levels. Several non-piliated, loss-of-function mutants were more sensitive to streptonigrin killing than the piliated parental strain. Consistent with the idea that higher available iron levels in the under- and non-piliated strains were responsible for the higher streptonigrin sensitivity, iron limitation by desferal chelation restored resistance to streptonigrin in these strains and the addition of iron restored the sensitivity to streptonigrin killing. The antioxidants tiron and dimethylthiourea rescued the pilE mutant from streptonigrin-mediated killing, suggesting that the elevated labile iron pool in non-piliated bacteria leads to streptonigrin-dependent reactive oxygen species production. These antioxidants did not affect LL-37-mediated killing. We confirmed that the pilE mutant is not more sensitive to other antibiotics showing that the streptonigrin phenotypes are not due to general bacterial envelope disruption. The total iron content of the cell was unaltered by piliation when measured using ICP-MS suggesting that only the labile iron pool is affected by piliation. These results support the hypothesis that piliation state affects N. gonorrhoeae iron homeostasis and influences sensitivity to various host-derived antimicrobial agents.
Topics: Bacterial Proteins; Fimbriae, Bacterial; Hydrogen Peroxide; Iron; Neisseria gonorrhoeae; Streptonigrin
PubMed: 35714158
DOI: 10.1371/journal.ppat.1010561 -
Archives of Biochemistry and Biophysics Sep 2022Several compounds have been found capable of diverting the electron flow in Escherichia coli and thus causing increased intracellular production of O and HO. One...
Several compounds have been found capable of diverting the electron flow in Escherichia coli and thus causing increased intracellular production of O and HO. One indication of this electron-shunting action was increased cyanide-resistant respiration and one cellular response was increased biosynthesis of the manganese-containing superoxide dismutase and of catalase. Blocking cytochrome oxidase with cyanide or azide increased the electron flow available for reduction of paraquat and presumably of the other exogenous compounds tested and thus increased their biological effects. Paraquat, pyocyanine, phenazine methosulfate, streptonigrin, juglone, menadione, plumbagin, methylene blue, and azure C were all effective in elevating intracellular production of O and HO. The effect of alloxan appeared paradoxical in that it increased cyanide-resistant respiration without significantly increasing the cell content of the manganese-superoxide dismutase and with only a small effect on the level of catalase. The alloxan effect on cyanide-resistant respiration was artifactual and was due to an oxygen-consuming reaction between alloxan and cyanide, rather than to a diversion of the intracellular electron flow. With paraquat as a representative electron-shunting compound, the increase in biosynthesis of the manganese-superoxide dismutase was prevented by inhibitors of transcription or of translation, but not by an inhibitor of replication. The increase in this enzyme activity, caused by paraquat and presumably by the other compounds, was thus due to de novo enzyme synthesis activated or derepressed at the level of transcription.
Topics: Alloxan; Catalase; Cyanides; Escherichia coli; Hydrogen Peroxide; Manganese; Oxidation-Reduction; Oxygen; Paraquat; Superoxide Dismutase; Superoxides
PubMed: 35660299
DOI: 10.1016/j.abb.2022.109229 -
Journal of Microbiology, Immunology,... Dec 2022Klebsiella pneumoniae is a gram-negative opportunistic pathogen that causes diseases mostly in immunocompromised individuals. Recently, hypervirulent K. pneumoniae...
BACKGROUND
Klebsiella pneumoniae is a gram-negative opportunistic pathogen that causes diseases mostly in immunocompromised individuals. Recently, hypervirulent K. pneumoniae strains also cause severe disease in healthy individuals. Capsular polysaccharide (CPS) is the major virulence determinant in hypervirulent K. pneumoniae and protects the cell against the bactericidal activity of the immune system. Gallic acid (GA), a natural phenolic compound, is known to exhibit wide spectrum antibacterial activity; however, its effect on hypervirulent K. pneumoniae remains largely unresolved. We aimed to identify the effects of GA on CPS biosynthesis in hypervirulent K. pneumoniae.
METHODS
Antibacterial activity of GA was evaluated by counting colonies. CPS amount was determined by glucuronic acid content. The transcriptions of cps gene cluster were measured by quantitative real time PCR (qRT-PCR) and the β-galactosidase activity. The effect of GA on the resistance of K. pneumoniae to streptonigrin (SNG), an iron-activated antibiotic, was evaluated. The effect of GA on the resistance of K. pneumoniae to serum killing and phagocytosis by macrophages was observed.
RESULTS
GA inhibited the growth and CPS biosynthesis in K. pneumoniae. GA may affect the iron availability in K. pneumoniae, thus possibly repressing the cps transcription. In addition, GA reduced the resistance of K. pneumoniae to serum killing and enhanced its susceptibility to phagocytosis.
CONCLUSION
GA possesses bactericidal activity and inhibits the CPS biosynthesis in hypervirulent K. pneumoniae, thereby facilitating pathogen clearance by the host immune system. Therefore, GA may represent a promising strategy for the prevention or treatment of patients with hypervirulent K. pneumoniae infections.
Topics: Humans; Klebsiella pneumoniae; Gallic Acid; Virulence Factors; Anti-Bacterial Agents; Iron; Klebsiella Infections
PubMed: 34326026
DOI: 10.1016/j.jmii.2021.07.002 -
Environmental Microbiology Sep 2021Xanthomonas oryzae pv. oryzae (Xoo) causes a serious disease of rice known as bacterial leaf blight. Several virulence-associated functions have been characterized in...
Xanthomonas oryzae pv. oryzae (Xoo) causes a serious disease of rice known as bacterial leaf blight. Several virulence-associated functions have been characterized in Xoo. However, the role of important second messenger c-di-GMP signalling in the regulation of virulence-associated functions still remains elusive in this phytopathogen. In this study we have performed an investigation of 13 c-di-GMP modulating deletion mutants to understand their contribution in Xoo virulence and lifestyle transition. We show that four Xoo proteins, Xoo2331, Xoo2563, Xoo2860 and Xoo2616, are involved in fine-tuning the in vivo c-di-GMP abundance and also play a role in the regulation of virulence-associated functions. We have further established the importance of the GGDEF domain of Xoo2563, a previously characterized c-di-GMP phosphodiesterase, in the virulence-associated functions of Xoo. Interestingly the strain harbouring the GGDEF domain deletion (ΔXoo2563 ) exhibited EPS deficiency and hypersensitivity to streptonigrin, indicative of altered iron metabolism. This is in contrast to the phenotype exhibited by an EAL overexpression strain wherein, the ΔXoo2563 exhibited other phenotypes, similar to the strain overexpressing the EAL domain. Taken together, our results indicate a complex interplay of c-di-GMP signalling with the cell-cell signalling to coordinate virulence-associated function in Xoo.
Topics: Bacterial Proteins; Cyclic GMP; Gene Expression Regulation, Bacterial; Plant Diseases; Virulence; Xanthomonas
PubMed: 34240791
DOI: 10.1111/1462-2920.15664 -
Journal of Biomolecular Structure &... 2022Antibiotic resistance is a global concern. Two members of the bacterial genus namely, and have raised much concern in recent years because of their resistance to...
Antibiotic resistance is a global concern. Two members of the bacterial genus namely, and have raised much concern in recent years because of their resistance to multiple commonly used antibiotics. Identification of multidrug resistant and pan-drug resistant bacteria has propelled the search for new antibiotics that can act on unconventional targets. Researches are going on to find out the possibility of using bacterial ribonucleotide reductases as a novel target for antibiotic development. Through evaluations, this study aims for characterization and functional annotation of ribonucleotide reductase enzymes of and . Binding affinities with these enzymes of the compounds that have shown promising results in inhibiting growth by acting on its ribonucleotide reductase were also assessed by molecular docking and dynamics simulations. Insights from this study will help in battling these infections in the near future. Communicated by Ramaswamy H. Sarma.
Topics: Humans; Ribonucleotide Reductases; Molecular Docking Simulation; Streptonigrin; Flavobacteriaceae Infections; Genome, Bacterial; Phylogeny; Anti-Bacterial Agents
PubMed: 34048660
DOI: 10.1080/07391102.2021.1930166 -
PloS One 2021The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression...
The foodborne pathogen Listeria monocytogenes is able to survive across a wide range of intra- and extra-host environments by appropriately modulating gene expression patterns in response to different stimuli. Positive Regulatory Factor A (PrfA) is the major transcriptional regulator of virulence gene expression in L. monocytogenes. It has long been known that activated charcoal is required to induce the expression of PrfA-regulated genes in complex media, such as Brain Heart Infusion (BHI), but not in chemically defined media. In this study, we show that the expression of the PrfA-regulated hly, which encodes listeriolysin O, is induced 5- and 8-fold in L. monocytogenes cells grown in Chelex-treated BHI (Ch-BHI) and in the presence of activated charcoal (AC-BHI), respectively, relative to cells grown in BHI medium. Specifically, we show that metal ions present in BHI broth plays a role in the reduced expression of the PrfA regulon. In addition, we show that expression of hly is induced when the levels of bioavailable extra- or intercellular iron are reduced. L. monocytogenes cells grown Ch-BHI and AC-BHI media showed similar levels of resistance to the iron-activated antibiotic, streptonigrin, indicating that activated charcoal reduces the intracellular labile iron pool. Metal depletion and exogenously added glutathione contributed synergistically to PrfA-regulated gene expression since glutathione further increased hly expression in metal-depleted BHI but not in BHI medium. Analyses of transcriptional reporter fusion expression patterns revealed that genes in the PrfA regulon are differentially expressed in response to metal depletion, metal excess and exogenous glutathione. Our results suggest that metal ion abundance plays a role in modulating expression of PrfA-regulated virulence genes in L. monocytogenes.
Topics: Bacterial Proteins; Bacterial Toxins; Charcoal; Culture Media; Gene Expression Regulation, Bacterial; Glutathione; Heat-Shock Proteins; Hemolysin Proteins; Iron; Listeria monocytogenes; Peptide Termination Factors; Polystyrenes; Polyvinyls; Streptonigrin; Virulence; Zinc
PubMed: 33914817
DOI: 10.1371/journal.pone.0250989