Search Results (6)

Breast cancer is one of the leading causes of cancer death. Recent studies found that arylamine N-acetyltransferase 1 (NAT1) is frequently upregulated in breast cancer, further suggesting NAT1 could be a potential therapeutic target for breast cancer. Previous publications have established that NAT1 knockout (KO) in breast cancer cell lines leads to growth reduction both in vitro and in vivo and metabolic changes. These reports suggest that NAT1 contributes to the energy metabolism of breast cancer cells. Proteomic analysis and non-targeted metabolomics suggested that NAT1 KO may change the fate of glucose as it relates to the TCA/KREB cycle of the mitochondria of breast cancer cells. In this current study, we used [U-¹³C]-glucose stable isotope resolved metabolomics to determine the effect of NAT1 KO on the metabolic profile of MDA-MB-231 breast cancer cells. We incubated breast cancer cells (MDA-MB-231 cells) and NAT1 Crispr KO cells (KO#2 and KO#5) with [U-¹³C]-glucose for 24 h. Tracer incubation polar metabolites from the cells were extracted and analyzed by 2DLC-MS, and metabolite differences were compared between the parental and NAT1 KO cells. Differences consistent between the two KO cells were considered changes due to the loss of NAT1. The data revealed decreases in the ¹³C enrichment of TCA/Krebs cycle intermediates in NAT1 KO cells compared to the MDA-MB-231 cells. Specifically, ¹³C-labeled citrate, isocitrate, a-ketoglutarate, fumarate, and malate were all decreased in NAT1 KO cells. We also detected increased ¹³C-labeled L-lactate levels in the NAT1 KO cells and decreased ¹³C enrichment in some nucleotides. Pathway analysis showed that arginine biosynthesis, alanine, aspartate and glutamate metabolism, and the TCA cycle were most affected. These data provide additional evidence supporting the impacts of NAT1 knockout on cellular energy metabolism. The data suggest that NAT1 expression is important for the proper functioning of mitochondria and the flux of glucose through the TCA/Krebs cycle in breast cancer cells. The metabolism changes in the fate of glucose in NAT1 KO breast cancer cells offer more insight into the role of NAT1 in energy metabolism and the growth of breast cancer cells. These data provide additional evidence that NAT1 may be a useful therapeutic target for breast cancer. Full article

In this study, the inhibitory potential of 3-(5-nitrofuran-2-yl)prop-2-en-1-one derivatives was evaluated against a panel of bacteria, as well as mammalian cell lines to determine their therapeutic index. In addition, we investigated the mechanism of antibiotic action of the derivatives to identify their therapeutic target. We discovered compound 2 to be an extremely potent inhibitor of Mycobacterium tuberculosis H37Rv growth (MIC: 0.031 mg/L) in vitro, performing better than the currently used first-line antituberculosis drugs such as isoniazid, rifampicin, ethambutol, and pretomanid in vitro. Furthermore, compound 3 was equipotent to pretomanid against a multidrug-resistant M. tuberculosis clinical isolate. The derivatives were selective and bactericidal towards slow-growing mycobacteria. They showed low cytotoxicity towards murine RAW 264.7 and human THP-1 cell lines, with high selectivity indices. Compound 1 effectively eliminated the intracellular mycobacteria in a mycobacteria-infected macrophage model. The derivatives were assessed for their potential to inhibit mycobacterial arylamine N-acetyltransferase (NAT) and were identified as good inhibitors of recombinant mycobacterial NAT, a novel target essential for the intracellular survival of M. tuberculosis. This study provided hits for designing new potent and selective antituberculosis leads, having mycobacterial NAT inhibition as their possible endogenous mechanisms of action. Full article

This study explored the antitubercular properties of fucoxanthin, a marine carotenoid, against clinical isolates of Mycobacterium tuberculosis (Mtb). Two vital enzymes involved in Mtb cell wall biosynthesis, UDP-galactopyranose mutase (UGM) and arylamine-N-acetyltransferase (TBNAT), were selected as drug targets to reveal the mechanism underlying the antitubercular effect of fucoxanthin. The obtained results showed that fucoxanthin showed a clear bacteriostatic action against the all Mtb strains tested, with minimum inhibitory concentrations (MIC) ranging from 2.8 to 4.1 µM, along with a good degree of selectivity index (ranging from 6.1 to 8.9) based on cellular toxicity evaluation compared with standard drug isoniazid (INH). The potent inhibitory actions of fucoxanthin and standard uridine-5’-diphosphate against UGM were recorded to be 98.2% and 99.2%, respectively. TBNAT was potently inactivated by fucoxanthin (half maximal inhibitory concentration (IC₅₀) = 4.8 µM; 99.1% inhibition) as compared to INH (IC₅₀ = 5.9 µM; 97.4% inhibition). Further, molecular docking approaches were achieved to endorse and rationalize the biological findings along with envisaging structure-activity relationships. Since the clinical evidence of the last decade has confirmed the correlation between bacterial infections and autoimmune diseases, in this study we have discussed the linkage between infection with Mtb and autoimmune diseases based on previous clinical observations and animal studies. In conclusion, we propose that fucoxanthin could demonstrate great therapeutic value for the treatment of tuberculosis by acting on multiple targets through a bacteriostatic effect as well as by inhibiting UGM and TBNAT. Such outcomes may lead to avoiding or decreasing the susceptibility to autoimmune diseases associated with Mtb infection in a genetically susceptible host. Full article

The current study explores the antimycobacterial efficacy of lichen-derived psoromic acid (PA) against clinical strains of Mycobacterium tuberculosis (M.tb). Additionally, the inhibitory efficacy of PA against two critical enzymes associated with M.tb, namely, UDP-galactopyranose mutase (UGM) and arylamine-N-acetyltransferase (TBNAT), as drug targets for antituberculosis therapy were determined. PA showed a profound inhibitory effect towards all the M.tb strains tested, with minimum inhibitory concentrations (MICs) ranging between 3.2 and 4.1 µM, and selectivity indices (SIs) ranging between 18.3 and 23.4. On the other hand, the standard drug isoniazid (INH) displayed comparably high MIC values (varying from 5.4 to 5.8 µM) as well as low SI values (13.0–13.9). Interestingly, PA did not exhibit any cytotoxic effects on a human liver hepatocellular carcinoma cell line even at the highest concentration tested (75 µM). PA demonstrated remarkable suppressing propensity against UGM compared to standard uridine-5'-diphosphate (UDP), with 85.8 and 99.3% of inhibition, respectively. In addition, PA also exerted phenomenal inhibitory efficacy (half maximal inhibitory concentration (IC₅₀) value = 8.7 µM, and 77.4% inhibition) against TBNAT compared with standard INH (IC₅₀ value = 6.2 µM and 96.3% inhibition). Furthermore, in silico analysis validated the outcomes of in vitro assays, as the molecular interactions of PA with the active sites of UGM and TBNAT were unveiled using molecular docking and structure–activity relationship studies. Concomitantly, our findings present PA as an effective and safe natural drug plausible for use in controlling tuberculosis infections. Full article

Novel drugs to treat tuberculosis are required and the identification of potential targets is important. Piperidinols have been identified as potential antimycobacterial agents (MIC < 5 μg/mL), which also inhibit mycobacterial arylamine N-acetyltransferase (NAT), an enzyme essential for mycobacterial survival inside macrophages. The NAT inhibition involves a prodrug-like mechanism in which activation leads to the formation of bioactive phenyl vinyl ketone (PVK). The PVK fragment selectively forms an adduct with the cysteine residue in the active site. Time dependent inhibition of the NAT enzyme from Mycobacterium marinum (M. marinum) demonstrates a covalent binding mechanism for all inhibitory piperidinol analogues. The structure activity relationship highlights the importance of halide substitution on the piperidinol benzene ring. The structures of the NAT enzymes from M. marinum and M. tuberculosis, although 74% identical, have different residues in their active site clefts and allow the effects of amino acid substitutions to be assessed in understanding inhibitory potency. In addition, we have used the piperidinol 3-dimensional shape and electrostatic properties to identify two additional distinct chemical scaffolds as inhibitors of NAT. While one of the scaffolds has anti-tubercular activity, both inhibit NAT but through a non-covalent mechanism. Full article

Fusarium avenaceum is a common soil saprophyte and plant pathogen of a variety of hosts worldwide. This pathogen is often involved in the crown rot and head blight of cereals that affects grain yield and quality. F. avenaceum contaminates grain with enniatins more than any species, and they are often detected at the highest prevalence among fusarial toxins in certain geographic areas. We studied intraspecific variability of F. avenaceum based on partial sequences of elongation factor-1 alpha, enniatin synthase, intergenic spacer of rDNA, arylamine N-acetyltransferase and RNA polymerase II data sets. The phylogenetic analyses incorporated a collection of 63 F. avenaceum isolates of various origin among which 41 were associated with wheat. Analyses of the multilocus sequence (MLS) data indicated a high level of genetic variation within the isolates studied with no significant linkage disequilibrium. Correspondingly, maximum parsimony analyses of both MLS and individual data sets showed lack of clear phylogenetic structure within F. avenaceum in relation to host (wheat) and geographic origin. Lack of host specialization indicates no host selective pressure in driving F. avenaceum evolution, while no geographic lineage structure indicates widespread distribution of genotypes that resulted in nullifying the effects of geographic isolation on the evolution of this species. Moreover, significant incongruence between all individual tree topologies and little clonality is consistent with frequent recombination within F. avenaceum. Full article