identifying-pd-1pd-l1-inhibitors-with-surface-plasmon-resonance

Identifying PD-1/PD-L1 Inhibitors with Surface Plasmon Resonance Technology

The disruption of the PD-1/PD-L1 interaction is a promising strategy for cancer immunotherapy. Reliable screening platforms are essential for evaluating ...

University of Rhode Island

Blockade of the programmed cell death protein 1 (PD-1)/PD-ligand 1 (PD-L1) axis is a promising strategy for cancer immunotherapy. Although antibody-based PD-1/PD-L1 inhibitors have shown remarkable results in clinical cancer studies, their inherent limitations underscore the significance of developing novel PD-1/PD-L1 inhibitors. Small molecule inhibitors have several advantages over antibody-based inhibitors, including favorable tumor penetration and oral bioavailability, fewer side effects, easier administration, preferred biological half-life, and lower cost. However, small molecule inhibitors that directly target the PD-1/PD-L1 interaction are still in the early development stage, partially due to the lack of reliable biophysical assays. Herein, we present a novel PD-1/PD-L1 blockade assay using a surface plasmon resonance (SPR)-based technique. This blockade assay immobilizes human PD-1 on a sensor chip, which interacts with PD-L1 inhibitors or negative PD-L1 binders with human PD-L1 protein at a range of molecular ratios. The binding kinetics of PD-L1 to PD-1 and the blockade rates of small molecules were determined. Compared to other techniques such as PD-1/PD-L1 pair enzyme-linked immunosorbent assay (ELISA) and AlphaLISA immunoassays, our SPR-based method offers real-time and label-free detection with advantages including shorter experimental runs and smaller sample quantity requirements. Key features A SPR protocol screens compounds for their capacity to block the PD-1/PD-L1 interaction. Validation of PD-1/PD-L1 interaction, followed by assessing blockade effects with known inhibitors BMS-1166 and BMS-202, and a negative control NO-Losartan A. Analysis of percentage blockade of PD-1/PD-L1 of the samples to obtain the IC. Broad applications in the discovery of small molecule-based PD-1/PD-L1 inhibitors for cancer immunotherapy. Graphical overview.

Establishment of Human PD-1/PD-L1 Blockade Assay Based on Surface Plasmon Resonance (SPR) Biosensor.

Erratum: Correction Notice: Establishment of Human PD-1/PD-L1 Blockade Assay Based on Surface Plasmon Resonance (SPR) Biosensor.

Oleuropein (OLE) and hydroxytyrosol (HT) are dietary polyphenols with skin beneficial effects but their effects on skin-ageing-related enzymes are not clear. Herein, we evaluated their inhibitory effects on elastase and collagenase. OLE and HT (62.5-1 000 μM) showed moderate anti-elastase and anti-collagenase effects (5.1-26.3%, 5.8-12.2% and 12.6-31.0%, 11.6-31.9% inhibition, respectively). Combinations of OLE and HT (1:1 ratio) exerted synergistic inhibitory effects on elastase, which were supported by their combination index (CI), kinetic assay and computational docking. Moreover, HT (100 μM) reduced hydrogen peroxide (HO)-induced cytotoxicity and reactive oxygen species (ROS) in human dermal fibroblast cells by 21.8 and 15.2%, respectively. In addition, combinations of OLE and HT (6.25/6.25-100/100 μM) exerted synergistic cytoprotective effects by reducing ROS levels by 7.6-37.3% with CIs of 0.17-0.44, respectively. The findings from this study support the cosmeceutical activities of OLE and HT but further research is warranted to evaluate their anti-skin-ageing effects using in vivo models.

Dietary polyphenol oleuropein and its metabolite hydroxytyrosol are moderate skin permeable elastase and collagenase inhibitors with synergistic cellular antioxidant effects in human skin fibroblasts.

 , a traditional Chinese medicine for treating conditions associated with abnormal skin pigmentation, contains flavonoids with inhibitory effects on tyrosinase. However, their mechanisms of action and their modulatory effects on melanogenesis remain unclear.  Herein, a group of prenylated flavonoids was identified from  extracts and their inhibitory activities on mushroom tyrosinase were evaluated. The anti-melanogenesis effects of these prenylated flavonoids were investigated in cellular (with murine melanoma cells) and animal (with zebrafish) models.  Prenylated flavonoids including isoanhydroicaritin (IAI), kurarinone (KR), and sophoraflavanone G (SG) were the major active constituents in  extracts with anti-tyrosinase activity (IC = 0.7, 7.1, and 6.7 μM, respectively). Enzyme kinetic assays showed that IAI, KR, and SG had a mixed type of tyrosinase inhibition, supported by data from computational docking. Notably, KR at concentrations of 5 and 10 μM enhanced intracellular tyrosinase activity and stimulated melanin production in B16F10 cells, whereas SG and IAI did not exhibit significant activity. Further studies with the zebrafish model showed that IAI (80 and 160 μM) inhibited melanin biosynthesis by about 30.0% while KR (20 μM) stimulated melanogenesis by 36.9%. Furthermore, a zebrafish depigmentation model supported the anti-melanogenesis effect of IAI (80 and 160 μM) by 33.0% and 34.4%, respectively.  In summary, IAI was identified as a tyrosinase inhibitor with an anti-melanogenic effect and KR was an enhancer for melanin production in B16F10 cells and zebrafish. Findings from the current study suggest that IAI and KR from  may exert contrasting effects in the modulation of melanin production, providing important insights into the development of  as a cosmeceutical or medicinal ingredient.

Article	Year
Establishment of Human PD-1/PD-L1 Blockade Assay Based on Surface Plasmon Resonance (SPR) Biosensor. Bio-protocol\| PubMed ID: 37575393	2023
Erratum: Correction Notice: Establishment of Human PD-1/PD-L1 Blockade Assay Based on Surface Plasmon Resonance (SPR) Biosensor. Bio-protocol\| PubMed ID: 38152682	2023
Dietary polyphenol oleuropein and its metabolite hydroxytyrosol are moderate skin permeable elastase and collagenase inhibitors with synergistic cellular antioxidant effects in human skin fi... International journal of food sciences and nutrition\| PubMed ID: 34719319	2022
Prenylated flavonoids from inhibit mushroom tyrosinase activity and modulate melanogenesis in murine melanoma cells and zebrafish. Frontiers in pharmacology\| PubMed ID: 39050754	2024

Justin Gutkowski

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