Biology subjects

Gabr, M.

Publications and source records attributed to Gabr, M..

4 recordsLinked to original sources

bioRxiv2024

From Virtual Screens to Cellular Target Engagement: New Small Molecule Ligands for the Immune Checkpoint LAG-3

Herein, we performed a virtual screening study to discover new scaffolds for small molecule-based ligands of the immune checkpoint lymphocyte-activation gene 3 (LAG-3). Molecular dynamics (MD) simulations using the LAG-3 structure revealed two putative binding sites for small molecules: the antibody interface and a lipophilic canyon. A 3D pharmacophore screening resulted in the identification of potential ligands for these binding sites and afforded a library of 25 compounds. We then evaluated the screening hits for LAG-3 binding via microscale thermophoresis (MST) and surface plasmon resonance (SPR). Our biophysical screening identified two binders with KD values in the low micromolar range, compounds 3 (antibody interface) and 25 (lipophilic canyon). Furthermore, we investigated the ability of LAG-3 hits to en-gage LAG-3 on a cellular level using a cellular thermal shift assay (CETSA), where compound 3 emerged as a promising candidate for future development.

pharmacology and toxicology↗

bioRxiv2024

Discovery of ICOS-targeted small molecules using affinity selection mass spectrometry screening

Inducible T cell co-stimulator (ICOS) is a positive immune checkpoint receptor expressed on the surface of activated T cells, which could promote cell function after being stimulated with ICOS ligand (ICOS-L). Although clinical benefits have been reported in the ICOS modulation-based treatment for cancer and autoimmune disease, current modulators are restricted in biologics, whereas ICOS-targeted small molecules are lacking. To fill this gap, we performed an affinity selection mass spectrometry (ASMS) screening for ICOS binding using a library of 15,600 molecules. To the best of our knowledge, this is the first study that utilizes ASMS screening to discover small molecules targeting immune checkpoints. Compound 9 with a promising ICOS/ICOS-L inhibitory profile (IC50 = 29.38 {+/-} 3.41 {micro}M) was selected as the template for the modification. Following preliminary structure-activity relationship (SAR) study and molecular dynamic (MD) simulation revealed the critical role of the ortho-hydroxy group on compound 9 in the ICOS binding, as it could stabilize the interaction via the hydrogen bond formation with residuals on the glycan, and the depletion could lead to an activity lost. This work validates a promising inhibitor for the ICOS/ICOS-L interaction, and we anticipate future modifications could provide more potent modulators for this interaction.

pharmacology and toxicology↗

bioRxiv2024

Design and Biophysical Characterization of Second-Generation Cyclic Peptide LAG-3 Inhibitors for Cancer Immunotherapy

Lymphocyte activation gene 3 (LAG-3) is an inhibitory immune checkpoint crucial for suppressing the immune response against cancer. Blocking LAG-3 interactions enables T cells to recover their cytotoxic capabilities and diminishes the immunosuppressive effects of regulatory T cells. A cyclic peptide (Cys-Val-Pro-Met-Thr-Tyr-Arg-Ala-Cys, disulfide bridge: 1-9) was recently reported as a LAG-3 inhibitor. Based on this peptide, we designed 19 derivatives by substituting tyrosine residue to maximize LAG-3 inhibition. Screening via TR-FRET assay identified 8 outperforming derivatives, with cyclic peptides 12 [Tyr6(L-3-CN-Phe)], 13 [Tyr6(L-4-NH2-Phe)], and 17 [Tyr6(L-3,5-DiF-Phe)] as top candidates. Cyclic peptide 12 exhibited the highest inhibition (IC50 = 4.45 {+/-} 1.36 {micro}M). MST analysis showed cyclic peptides 12 and 13 bound LAG-3 with KD values of 2.66 {+/-} 2.06 {micro}M and 1.81 {+/-} 1.42 {micro}M, respectively, surpassing the original peptide (9.94 {+/-} 4.13 {micro}M). Docking simulations indicated enhanced binding for cyclic peptide 12, with a docking score of -7.236 kcal/mol compared to -5.236 kcal/mol for the original peptide.

pharmacology and toxicology↗

bioRxiv2021

The use of autologous skeletal muscle-derived cells as a sling in the treatment of induced stress urinary incontinence, an experimental study

Introduction & hypothesisThis is an experimental pre-clinical study testing for the applicability of autologous skeletal muscle derived cells as a seeded sling for the treatment of SUI in the canine model Methods10 Mongrel dogs: In 4, skeletal muscle biopsy was harvested from Biceps Femoris. 1 month later, incontinence was induced in 8 dogs through surgical disruption of the pubourethral ligaments. Muscle biopsy was incubated in DMEM medium and after expansion for 8 weeks, MDCs were collected. PGA scaffold was immersed in culture medium, coated with matrigel and cells were seeded. The sling was placed suburethrally in 8 dogs; 2 of which were cell-seeded and 4 had the scaffold only. Urethral pressure (UP) measurement was done at baseline and 2 weeks alter insertion of the sling. The urethra with its surrounding was harvested 4 weeks after sling insertion for histopathology. 2 dogs were considered as control, in which no urethrolysis or insertion of slings were carried out ResultsUP show increase of maximum urethral pressure during static measurement in all dogs with a scaffold inserted. The increase ranged from 5-40 cmH20 (Median 23 cmH20) Histopathology shows significant periurethral proliferation of skeletal muscles in 4 dogs with cell-seeded scaffold, as demonstrated by Desmin. This was maximum in dogs # 1& 2. This was not the case in the 4 dogs that had PGA sling only. ConclusionThe use of skeletal muscle -seeded PGA scaffold is a practical technique with preserved integrity of histological differentiation in canine model at short term. Brief SummaryAutologous Skeletal muscle-derived cells could be propagated in vitro and seeded to PGS scaffolds and used as slings

developmental biology↗