Conformational Properties of Aryl S-Glucosides in Solution.

The conformational study of saccharides and glycomimetics in solution is critical for a comprehensive understanding of their interactions with biological receptors and enabling the design of optimized glycomimetics. Here, we report a nuclear magnetic resonance (NMR) study centered on the conformational properties of the hydroxymethyl group and glycosidic bond of four series of aryl S-glucosides. We found that in acetyl-protected and free aryl S-ß-glucosides, the rotational equilibrium around the C5-C6 bond (hydroxymethyl group) exhibits a linear dependence on the electronic properties of the aglycone, namely, as the aryl's substituent electron-withdrawing character increases, the dominance of the gg rotamer declines and the gt contribution rises. Likewise, the conformational equilibrium around the glycosidic C1-S bond also depends on the aglycone's electronic properties, where glucosides carrying electron-poor aglycones exhibit stiffer glycosidic bonds in comparison to their electron-rich counterparts. In the case of the α anomers, the aglycone's effect over the glycosidic bond conformation is like that observed on their ß isomers; however, we observe no aglycone's influence over the hydroxymethyl group conformation in the α-glucosides.

Cetuximab-based PROteolysis targeting chimera for effectual downregulation of NSCLC with varied EGFR mutations.

PROteolysis Targeting Chimeras (PROTACs) showed tremendous therapeutic potential in degrading several oncoproteins including undruggable proteins. PROTACs are bifunctional molecules where one-part binds to target protein while the other end recruits protein degradation machinery. With the unveiling advancements in the field of PROTACs, we explored a combinatorial approach by developing antibody-based PROTAC (ABTAC) which may effectively degrade one of the key oncoprotein driving proliferation and progression of cancer - Epidermal growth factor receptor (EGFR). The objective of current research was to synthesize and characterize an EGFR degrading ABTAC for the treatment of non-small cell lung cancer (NSCLC). Cetuximab and pomalidomide (E3 ligase recruiting ligand) were conjugated using lysine conjugation and copper free azide-alkyne cycloaddition (CuAAC) click chemistry. Analytical characterization using reverse-phase liquid chromatography and mass spectrometry suggested conjugation of five E3-ligase inhibitor molecules/antibody. Nearly 10-30 folds reduction in IC50 was observed with ABTAC in HCC827 (EGFR sensitive) and H1650 (EGFR resistant) cells compared to cetuximab. Multicellular 3D spheroid assay strongly suggested that ABTAC induced significant apoptosis and also inhibited cell proliferation compared to control and antibody alone. Circular dichroism and surface plasmon resonance (SPR) confirmed minor alterations in the structure and receptor binding efficacy of the antibody post-conjugation.

A Ferrier glycosylation/cis-dihydroxylation strategy to synthesize Leishmania spp. lipophosphoglycan-associated ßGal(1,4)Man disaccharide.

The Galß(1→4)Man disaccharide, found in the cell surface lipophosphoglycan (LPG) of Leishmania species, has been synthesized by a Ferrier glycosylation/cis-dihydroxylation strategy. This stereoselective method proved efficient for synthesizing the target saccharide in good yield. In addition, we prepared two clickable O-glycoside and phospho-glycoside versions of Galß(1→4)Man to enable conjugation to protein carriers for further immunological and antibody-binding studies.

Bictegravir nanomicelles and anionic pullulan loaded vaginal film: Dual mechanistic pre-exposure prophylaxis (PrEP) for HIV.

Locally delivered pre-exposure prophylaxis (PrEP) has proven to be a promising strategy to combat Human immunodeficiency virus (HIV) transmission but several findings encountered toxicities or proved to be marginally effective in clinical settings. Therefore, innovative, multifunctional, and safer alternatives are being progressively investigated. Herein, we explored negatively charged carbohydrate, anionic pullulan (AP) as a rapidly soluble film-former and novel anti-HIV agent. Additionally, Bictegravir (BCT), an HIV integrase inhibitor was co-delivered in the form of nanomicelles for sustained antiviral activity. BCT-loaded PLGA-PEG polymeric nanomicelles (BN) were incorporated into PVA/pullulan-based film matrix comprising of 2 % w/v AP (BN-AP film). In cell-based assays, biocompatibility and TEER values for BN-AP films were similar to control while the commercial vaginal contraceptive film (VCF®) showed severe cytotoxicity and drastically reduced the tight junction integrity. Rapid disintegration of BN-AP film with >85 % drug release was observed in simulated vaginal and seminal fluid. Most importantly, AP and BN-AP film significantly inhibited HIV-1 replication with IC50 at as low as 91 µg/mL and 0.708 nM, respectively. Therefore, this study entails successful development of BN-AP film that functioned as an effective, biocompatible dual-acting PrEP formulation.

Anodic Reactivity of Alkyl S-Glucosides.

A voltammetric study of a series of alkyl and aryl S-glucosides unveiled the reactivity patterns of alkyl S-glucosides toward anodic oxidation and found noteworthy differences with the trends followed by aryl derivatives. The oxidation potential of alkyl S-glucosides, estimated herein from square-wave voltammetry peak potentials (Ep), depends on the steric properties of the aglycone. Glucosides substituted with bulky groups exhibit Ep values at voltages more positive than the values of those carrying small aglycones. This relationship, observed in all analyzed alkyl series, is evidenced by good linear correlations between Ep and Taft's steric parameters (ES) of the respective alkyl substituents. Moreover, the role of the aglycone's steric properties as a primary reactivity modulator is backed by poor correlations between Ep and the radical stabilization energies (RSEs) of the aglycone-derived thiyl radicals (RS•). In contrast, aryl glucosides' Ep values exhibit excellent correlations with the aryl substituents' Hammett parameters (σ+) and the ArS• RSEs, evidencing the inherent stability of the reactive radical intermediate as the primary factor controlling aryl glucoside's electrochemical reactivity. The reactivity differences between alkyl and aryl S-glucosides also extend to the protective group's effect on Ep. Alkyl S-glucosides' reactivity proved to be more sensitive to protective group exchange.