Pyridylethanol(phenylethyl)amines are non-azole, highly selective Candida albicans sterol 14α-demethylase inhibitors

New Class of Hsp90 C-Terminal Domain Inhibitors with Anti-tumor Properties against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) remains a treatment challenge and requires innovative therapies. Hsp90, crucial for the stability of numerous oncogenic proteins, has emerged as a promising therapeutic target. In this study, we present the optimization of the Hsp90 C-terminal domain (CTD) inhibitor TVS21. Biochemical methods, NMR binding studies, and molecular modeling were employed to investigate the binding of representative analogs to Hsp90. The newly synthesized analogs showed increased antiproliferative activity in breast cancer cell lines, including the MDA-MB-231 TNBC cell line. Compounds 89 and 104 proved to be the most effective, inducing apoptosis, slowing proliferation, and degrading key oncogenic proteins without inducing a heat shock response. In vivo, compound 89 showed comparable efficacy to the clinical candidate AUY922 and a better safety profile in a TNBC xenograft model. These results highlight the promise of Hsp90 CTD inhibitors for TNBC therapy, potentially filling a significant treatment gap.

Multifunctional in vitro, in silico and DFT analyses on antimicrobial BagremycinA biosynthesized by Micromonospora chokoriensis CR3 from Hieracium canadense

Among the actinomycetes in the rare genera, Micromonospora is of great interest since it has been shown to produce novel therapeutic compounds. Particular emphasis is now on its isolation from plants since its population from soil has been extensively explored. The strain CR3 was isolated as an endophyte from the roots of Hieracium canadense, and it was identified as Micromonospora chokoriensis through 16S gene sequencing and phylogenetic analysis. The in-vitro analysis of its extract revealed it to be active against the clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Candida tropicalis (15 mm). No bioactivity was observed against Gram-negative bacteria, Escherichia coli ATCC 25922, and Klebsiella pneumoniae ATCC 706003. The Micromonospora chokoriensis CR3 extract was also analyzed through the HPLC-DAD-UV-VIS resident database, and it gave a maximum match factor of 997.334 with the specialized metabolite BagremycinA (BagA). The in-silico analysis indicated that BagA strongly interacted with the active site residues of the sterol 14-α demethylase and thymidylate kinase enzymes, with the lowest binding energies of - 9.7 and - 8.3 kcal/mol, respectively. Furthermore, the normal mode analysis indicated that the interaction between these proteins and BagA was stable. The DFT quantum chemical properties depicted BagA to be reasonably reactive with a HOMO-LUMO gap of (ΔE) of 4.390 eV. BagA also passed the drug-likeness test with a synthetic accessibility score of 2.06, whereas Protox-II classified it as a class V toxicity compound with high LD50 of 2644 mg/kg. The current study reports an endophytic actinomycete, M. chokoriensis, associated with H. canadense producing the bioactive metabolite BagA with promising antimicrobial activity, which can be further modified and developed into a safe antimicrobial drug.

The expression pattern, subcellular localization and function of three sterol 14α-demethylases in Aspergillus oryzae

Sterol 14α-demethylase catalyzes lanosterol hydroxylation, which is one of the key reactions in the biosynthetic pathway of sterols. There is only one sterol 14α-demethylases gene named Erg11 in Saccharomyces cerevisiae genome. In this study, three sterol 14α-demethylases genes named AoErg11A, AoErg11B and AoErg11C were identified in Aspergillus oryzae genome through bioinformatics analysis. The function of these three genes were studied by yeast complementation, and the expression pattern/subcellular localization of these genes/proteins were detected. The results showed that the three AoErg11s were expressed differently at different growth times and under different abiotic stresses. All of the three proteins were located in endoplasmic reticulum. The AoErg11s could not restore the temperature-sensitive phenotype of S. cerevisiae erg11 mutant. Overexpression of the three AoErg11s affected both growth and sporulation, which may be due to the effect of AoErg11s on ergosterol content. Therefore, this study revealed the functions of three AoErg11s and their effects on the growth and ergosterol biosynthesis of A. oryzae, which may contribute to the further understanding of the ergosterol biosynthesis and regulation mechanism in this important filamentous fungus, A. oryzae.

In silico study and biological screening of benzoquinazolines as potential antimicrobial agents against methicillin-resistant Staphylococcus aureus, carbapenem-resistant Klebsiella pneumoniae, and fluconazole-resistant Candida albicans

Globally, antibiotic-resistant pathogens have become a serious threat to public health. The use of drugs having structures different from those applied in the clinical treatments of bacterial infections is a well-known potential solution to the antibiotic resistance crisis. Benzo-[g]-quinazolines were identified by our research group as a new class of antimicrobial agents. Herein, to follow-up the research on such compounds, three benzo-[g]-quinazolines (1-3) were studied, as in vitro antibacterial candidates against methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Klebsiella pneumoniae, and fluconazole-resistant Candida albicans, as well. The minimum inhibitory concentration (MIC) assay for benzoquinazolines was carried out via the calorimetric broth microdilution method using the XTT assay in comparison with vancomycin, ciprofloxacin, and ketoconazole as reference drugs. The target compounds 1-3 revealed high variation in their activity against the examined resistant microbial strains. Benzoquinazoline 3 exhibited a more potent effect against the resistant strains compared with the reference drugs. A docking study was performed to identify the interactions between the benzoquinazolines 1-3 and ligand proteins (OXA-48 carbapenemase, β-lactamase, and sterol 14-alpha demethylase (CYP51)) at the active sites. Benzoquinazolines 1-3 showed very weak cytotoxicity against human lung fibroblast normal cells (WI-38). The targets showed promising antimicrobial effects against the three resistant strains. These findings may inform future inhibitor discoveries targeting penicillin-binding proteins.

Discovery of 1,2,3-selenadiazole analogues as antifungal agents using a scaffold hopping approach

With the increasing incidence of antifungal resistance, new antifungal agents having novel scaffolds hence are in an urgent need to combat infectious diseases caused by multidrug-resistant (MDR) pathogens. In this study, we reported the design, synthesis, and pharmacological evaluation of novel 1,2,3-selenadiazole analogues by scaffold hopping strategy. Preliminary results of antifungal activity demonstrated that the new class of compounds showed broad-spectrum fungistatic and fungicidal activity. Most importantly, these newly synthesized compounds can eliminate these azole-resistant fungi and inhibit the formation of C. albicans biofilm. In particular, compound S07 showed promising antifungal activity against five azole-resistant strains with MIC values ranging from 4 to 32 μg/mL. Then, further target identification and mechanistic studies indicated that representative compound S07 exert its inhibitory activity by inhibiting fungal lanosterol 14α-demethylase enzyme (CYP51). Interestingly, representative compounds showed low cytotoxicity on mammalian cell lines. In addition, the molecular docking studies elucidated the binding modes of these compounds toward CYP51. Altogether, these results suggest that compound S07 with novel skeleton is a promising CYP51 inhibitor for treatment of fungal infections.