Cholenic acid derivative UniPR1331 impairs tumor angiogenesis via blockade of VEGF/VEGFR2 in addition to Eph/ephrin

Optimizing ST6GAL1 inhibition and selectivity using lithocholic acid-amino acid conjugates for antimetastatic and antiangiogenic agent development

A series of LCA-aromatic amino acid conjugates were synthesized and tested for their inhibitory effects on N-glycan specific ST6GAL1 and O-glycan specific ST3GAL1. The LCA-amino acid conjugates with phenyl and indole moieties showed enhanced inhibitory activity and selectivity towards the N-glycan-specific ST6GAL1, with the indole-containing compound 4e exhibiting the highest activity (IC50 = 20.0 ± 0.5 μM). In addition, compound 4e exhibited the highest antimetastatic potential, effectively inhibiting MDA-MB-231 cell migration at non-cytotoxic concentrations. Compound 4e also suppressed tumor growth and metastasis in vivo, attributing to its potential to disrupt integrins sialylation. The conjugate has also demonstrated excellent antiangiogenetic properties in vitro and ex vivo, owing to its ability to downregulate the VEGF/VEGFR2/Akt pathway. Taken together, these findings prove the practicality of employing LCA as a scaffold and aromatic amino acid conjugation in the discovery of novel, potent, and selective ST inhibitors necessary to address abnormal cell surface α-2,6-N-sialylation.

Eph receptors and ephrins in cancer progression

Evidence implicating Eph receptor tyrosine kinases and their ephrin ligands (that together make up the 'Eph system') in cancer development and progression has been accumulating since the discovery of the first Eph receptor approximately 35 years ago. Advances in the past decade and a half have considerably increased the understanding of Eph receptor-ephrin signalling mechanisms in cancer and have uncovered intriguing new roles in cancer progression and drug resistance. This Review focuses mainly on these more recent developments. I provide an update on the different mechanisms of Eph receptor-ephrin-mediated cell-cell communication and cell autonomous signalling, as well as on the interplay of the Eph system with other signalling systems. I further discuss recent advances in elucidating how the Eph system controls tumour expansion, invasiveness and metastasis, supports cancer stem cells, and drives therapy resistance. In addition to functioning within cancer cells, the Eph system also mediates the reciprocal communication between cancer cells and cells of the tumour microenvironment. The involvement of the Eph system in tumour angiogenesis is well established, but recent findings also demonstrate roles in immune cells, cancer-associated fibroblasts and the extracellular matrix. Lastly, I discuss strategies under evaluation for therapeutic targeting of Eph receptors-ephrins in cancer and conclude with an outlook on promising future research directions.

Anti-angiogenic potential of bioactive phytochemicals from Helicteres isora targeting VEGFR-2 to fight cancer through molecular docking and molecular dynamics simulation

Cancer is one of the leading causes of death due to its very high rate of morbidity and mortality, and there is a constant demand of effective drugs for cancer therapy. Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a significant role as central modulator of angiogenesis and is targeted frequently for developing anti-angiogenic agents to fight cancer. Helicteres isora L. (Malvaceae) is reported to possess diverse medicinal properties including anti-cancer potentials. In the current investigation, 38 bioactive phytochemicals of H. isora were screened virtually to evaluate their anti-angiogenic potentials targeting VEGFR-2. The study unveiled three potential candidates such as, Diosgenin (-9.8 Kcal//mol), Trifolin (-8.4 Kcal/mol) and Yohimbine (-8.1 Kcal/mol) that showed favorable pharmacokinetic, pharmacodynamic and toxicity properties with no significant side effects. Molecular dynamics simulation employing 100 ns revealed noteworthy structural stability and compactness for all the top three candidates. The MM/GBSA binding free energy estimation corroborated the docking interactions where Yohimbine (-30.47 Kcal/mol) scored better than Diosgenin (-27.54 Kcal/mol) and Trifolin (-29.58 Kcal/mol). Target class prediction revealed enzymes in most of the cases and some FDA approved drugs were found as structurally similar analogs for Trifolin and Yohimbine. These findings could lead to the development of novel and effective anti-angiogenic agents.Communicated by Ramaswamy H. Sarma.

An innovative strategy to investigate microbial protein modifications in a reliable fast and sensitive way: A therapy oriented proof of concept based on UV-C irradiation of SARS-CoV-2 spike protein

The characterization of modifications of microbial proteins is of primary importance to dissect pathogen lifecycle mechanisms and could be useful in identifying therapeutic targets. Attempts to solve this issue yielded only partial and non-exhaustive results. We developed a multidisciplinary approach by coupling in vitro infection assay, mass spectrometry (MS), protein 3D modelling, and surface plasma resonance (SPR). As a proof of concept, the effect of low UV-C (273 nm) irradiation on SARS-CoV-2 spike (S) protein was investigated. Following UV-C exposure, MS analysis identified, among other modifications, the disruption of a disulphide bond within the conserved S2 subunit of S protein. Computational analyses revealed that this bond breakage associates with an allosteric effect resulting in the generation of a closed conformation with a reduced ability to bind the ACE2 receptor. The UV-C-induced reduced affinity of S protein for ACE2 was further confirmed by SPR analyses and in vitro infection assays. This comprehensive approach pinpoints the S2 domain of S protein as a potential therapeutic target to prevent SARS-CoV-2 infection. Notably, this workflow could be used to screen a wide variety of microbial protein domains, resulting in a precise molecular fingerprint and providing new insights to adequately address future epidemics.

Protein-Protein Interaction Inhibitors Targeting the Eph-Ephrin System with a Focus on Amino Acid Conjugates of Bile Acids

The role of the Eph-ephrin system in the etiology of pathological conditions has been consolidated throughout the years. In this context, approaches directed against this signaling system, intended to modulate its activity, can be strategic therapeutic opportunities. Currently, the most promising class of compounds able to interfere with the Eph receptor-ephrin protein interaction is composed of synthetic derivatives of bile acids. In the present review, we summarize the progresses achieved, in terms of chemical expansions and structure-activity relationships, both in the steroidal core and the terminal carboxylic acid group, along with the pharmacological characterization for the most promising Eph-ephrin antagonists in in vivo settings.