A concise synthesis of carbasugars isolated from Streptomyces lincolnensis

(–)-Quinic acid was used as a starting material in the hemisynthesis of two epimeric carbasugars isolated from Streptomyces lincolnensis. Previous 10–12 steps syntheses for the carbasugars have been herein shortened to 4–6 steps by using quinic acid as a chiron, based on a regioselective reduction step, with stereoinversion of a tertiary center. Both C-5 epimers of (1R, 2R, 3R)-5-(hydroxymethyl)cyclohexane-1,2,3-triol were obtained in up to 76% overall yield.publishe

Synthesis and preclinical validation of novel P2Y1 receptor ligands as a potent anti-prostate cancer agent.

Purinergic receptor is a potential drug target for neuropathic pain, Alzheimer disease, and prostate cancer. Focusing on the structure-based ligand discovery, docking analysis on the crystal structure of P2

Functional characterization of HIC, a P2Y1 agonist, as a p53 stabilizer for prostate cancer cell death induction

Background: (1-(2-hydroxy-5-nitrophenyl)(4-hydroxyphenyl)methyl)indoline-4-carbonitrile (HIC), an agonist of the P2Y1 receptor (P2Y1R), induces cell death in prostate cancer cells. However, the molecular mechanism behind the inhibition of HIC in prostate cancer remains elusive. Methods and results: Here, to outline the inhibitory role of HIC on prostate cancer cells, PC-3 and DU145 cell lines were treated with the respective IC50 concentrations, which reduced cell proliferation, adherence properties and spheroid formation. HIC was able to arrest the cell cycle at G1/S phase and also induced apoptosis and DNA damage, validated by gene expression profiling. HIC inhibited the prostate cancer cells' migration and invasion, revealing its antimetastatic ability. P2Y1R-targeted HIC affects p53, MAPK and NF-κB protein expression, thereby improving the p53 stabilization essential for G1/S arrest and cell death. Conclusion: These findings provide an insight on the potential use of HIC, which remains the mainstay treatment for prostate cancer.acceptedVersionPeer reviewe

P2Y1 agonist HIC in combination with androgen receptor inhibitor abiraterone acetate impairs cell growth of prostate cancer

P2Y receptors belong to the large superfamily of G-protein-coupled receptors and play a crucial role in cell death and survival. P2Y1 receptor has been identified as a marker for prostate cancer (PCa). A previously unveiled selective P2Y1 receptor agonist, the indoline-derived HIC (1-(1-((2-hydroxy-5-nitrophenyl)(4-hydroxyphenyl)methyl)indoline-4-carbonitrile), induces a series of molecular and biological responses in PCa cells PC3 and DU145, but minimal toxicity to normal cells. Here, we evaluated the combinatorial effect of HIC with abiraterone acetate (AA) targeted on androgen receptor (AR) on the inhibition of PCa cells. Here, the presence of HIC and AA significantly inhibited cell proliferation of PC3 and DU145 cells with time-dependent manner as a synerfistic combination. Moreover, it was also shown that the anticancer and antimetastasis effects of the combinratorial drugs were noticed through a decrease in colony-forming ability, cell migration, and cell invasion. In addition, the HIC + AA induced apoptotic population of PCa cells as well as cell cycle arrest in G1 progression phase. In summary, these studies show that the combination of P2Y1 receptor agonist, HIC and AR inhibitor, AA, effectively improved the antitumor activity of each drug. Thus, the combinatorial model of HIC and AA should be a novel and promising therapeutic strategy for treating prostate cancer.publishedVersionPeer reviewe

Cu-Catalyzed Tandem Oxidation-Intramolecular Cannizzaro Reaction of Biorenewables and Bioactive Molecules

A tandem Cu-catalyzed oxidation-intramolecular Cannizzaro reaction leading to bioactive α-hydroxyesters from α-hydroxyketones is reported. The process uses oxygen as a sole oxidant to achieve the formation of glyoxals, which are efficiently converted in situ to important α-hydroxyesters. The mechanistic insights are provided by isotopic labeling and supported by DFT calculations. The transformation proved a robust synthetic tool to achieve the synthesis of human metabolites and hydroxyl esters of various biologically active steroid derivatives.Peer reviewe

Ru-Catalyzed Isomerization of Achmatowicz Derivatives : A Sustainable Route to Biorenewables and Bioactive Lactones

A Ru-catalyzed isomerization of Achmatowicz derivatives that opens unexplored routes to diversify the biogenic furanic platform is reported. The mechanistic insights of this formally redox-neutral intramolecular process were studied computationally and by deuterium labeling. The transformation proved to be a robust synthetic tool to achieve the synthesis of bioderived-monomers and a series of 4-keto-δ-valerolactones that further enabled the development of a flexible strategy for the synthesis of acetogenins. A concise and protective group-free asymmetric total synthesis of two natural products, namely, (S,S)-muricatacin and the (S,S)-L-factor, is also described.publishedVersionPeer reviewe

Methanodibenzo[b,f][1,5]dioxocins as Novel Glutaminase Inhibitor with Anti-Glioblastoma Potential

Glutamine metabolism is an important hallmark of several cancers with demonstrated antitumor activity in glioblastoma cancer cells (GBM). GBM cells regulate glutamine and use it as a major energy source for their proliferation through the glutaminolysis process. Enzymes, such as glutaminase in glutaminolysis, can be targeted by small-molecule inhibitors, thus exhibiting promising anticancer properties. The resistance to glutaminolysis demands the development of new therapeutic molecules to overcome drug resistance. Herein, we have reported a novel library of constrained methanodibenzo[b,f][1,5]dioxocin derivatives as glutaminase (GLS) inhibitors and their anti-GBM potential. The library consisting of seven molecules was obtained through self-condensation of 2′-hydroxyacetophenones, out of which three molecules, namely compounds 3, 5, and 6, were identified with higher binding energy values ranging between −10.2 and −9.8 kcal/mol with GLS (PDB ID; 4O7D). Pharmacological validation of these compounds also showed a higher growth inhibition effect in GBM cells than the standard drug temozolomide (TMZ). The most promising compound, 6, obeyed Lipinski’s rule of five and was identified to interact with key residues Arg307, Asp326, Lys328, Lys399, and Glu403 of GLS. This compound exhibited the best cytotoxic effect with IC50 values of 63 µM and 83 µM in LN229 and SNB19 cells, respectively. The potential activation of GLS by the best-constrained dibenzo[b,f][1,5]dioxocin in the tested series increased apoptosis via reactive oxygen species production in both GBM cells, and exhibited anti-migratory and anti-proliferative properties over time in both cell lines. Our results highlight the activation mechanism of a dibenzo[b,f][1,5]dioxocin from the structural basis and demonstrate that inhibition of glutaminolysis may facilitate the pharmacological intervention for GBM treatment.publishedVersionPeer reviewe

Diketopyrrolo[3,4-c]pyrrole derivative as a promising ligand for the stabilization of G-quadruplex DNA structures

Telomerase, oncogenes and tumor suppressors are closely associated with tumour occurrence, therefore these structures are being recognized as targets for the development of new anticancer drugs. The efficacy of several molecules in telomerase inhibition and regulation of genes expression, by adduct formation with G-quadruplexes (G4), has been studied by biophysical and biochemical methods with promising results. We report here the synthesis and structural characterization of a small positively charged diketopyrrolo[3,4–c]pyrrole derivative, identified as DPP(PyMe)2, that showed very promising results as G4 stabilizing ligand. The data obtained from UV–Vis and fluorescence experiments suggest that DPP(PyMe)2 presents high affinity to G4 structures. Docking studies and molecular dynamics simulations unraveled the binding modes of the ligand with four G4 structures. The obtained results also allowed us to conclude that the DPP(PyMe)2 ligand binds into the top G-tetrad or in a mixed binding mode depending on the GQ structure. A remarkable selectivity of DPP(PyMe)2 for c-MYC and KRAS 32R in the presence of ds26 was observed by circular dichroism (CD) and fluorescence resonance energy transfer (FRET) melting experiments. CD titrations revealed a stabilization higher than 30 °C in the case of c-MYC G4 structure and, for the same sequence, DPP(PyMe)2 showed the ability to block the activity of Taq polymerase in a dose-dependent manner. The subcellular localization obtained with confocal microscopy corroborates the results obtained by the other techniques and the obtained data suggest that DPP(PyMe)2 is an attractive ligand for the development of G4 labelling probes.Peer reviewe

Increased antibacterial properties of indoline-derived phenolic Mannich bases

The search for antibacterial agents for the combat of nosocomial infections is a timely problem, as antibiotic-resistant bacteria continue to thrive. The effect of indoline substituents on the antibacterial properties of aminoalkylphenols was studied, leading to the development of a library of compounds with minimum inhibitory concentrations (MICs) as low as 1.18 μM. Two novel aminoalkylphenols were identified as particularly promising, after MIC and minimum bactericidal concentrations (MBC) determination against a panel of reference strain Gram-positive bacteria, and further confirmed against 40 clinical isolates (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium, and Listeria monocytogenes). The same two aminoalkylphenols displayed low toxicity against two in vivo models (Artemia salina brine shrimp and Saccharomyces cerevisiae). The in vitro cytotoxicity evaluation (on human keratinocytes and human embryonic lung fibroblast cell lines) of the same compounds was also carried out. They demonstrated a particularly toxic effect on the fibroblast cell lines, with IC50 in the 1.7-5.1 μM range, thus narrowing their clinical use. The desired increase in the antibacterial properties of the aminoalkylphenols, particularly indoline-derived phenolic Mannich bases, was reached by introducing an additional nitro group in the indolinyl substituent or by the replacement of a methyl by a bioisosteric trifluoromethyl substituent in the benzyl group introduced through use of boronic acids in the Petasis borono-Mannich reaction. Notably, the introduction of an additional nitro moiety did not confer added toxicity to the aminoalkylphenols.acceptedVersionPeer reviewe