Related Experiment Video
Updated: Sep 12, 2025
Identifying PD-1/PD-L1 Inhibitors with Surface Plasmon Resonance Technology
Published on: May 2, 2025
A light-resuming strategy as a screening method for selecting Sec61 inhibitors down-modulating PD-L1 expression
Fulvia Vitale1, Gianluca Scerra1, Laura Marrone1
1Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy.
Abstract:
The perturbation of protein translocation into the secretory pathway using Sec61 translocon inhibitors is a novel and promising strategy for tackling many pathological situations, including cancer and viral infections. However, a highly sensitive and direct screening platform for selecting Sec61 inhibitors is unavailable. Here, we develop a "resuming luminescence upon translocation interference" (RELITE) assay capable of selecting Sec61 inhibitors in a single round of screening. This assay exploits the inactivation of firefly luciferase, once translocated into the endoplasmic reticulum (ER), and the possibility of diverting and "re-lighting" luciferase into the cytosol by a Sec61 inhibitor. Using this method, we select small molecules capable of hampering the protein expression of the PD-L1 immune checkpoint by interfering with its ER translocation and delivering it for degradation. In conclusion, our screening method will greatly facilitate the selection of Sec61 inhibitors for down-modulating the expression of many disease-relevant proteins.
Insights
Researchers developed a novel assay to screen for Sec61 translocon inhibitors, crucial for targeting diseases like cancer. This new method identifies small molecules that block protein translocation, aiding in the development of new therapies.
Area of Science:
- Biochemistry
- Molecular Biology
- Drug Discovery
Background:
- Sec61 translocon inhibitors offer a promising strategy for treating cancers and viral infections.
- A sensitive and direct screening platform for identifying Sec61 inhibitors is currently lacking.
Purpose of the Study:
- To develop a novel, sensitive, and direct screening assay for Sec61 inhibitors.
- To identify small molecules that interfere with protein translocation into the endoplasmic reticulum (ER).
Main Methods:
- Development of the "resuming luminescence upon translocation interference" (RELITE) assay.
- Utilizing firefly luciferase translocation into the ER and its subsequent diversion to the cytosol by Sec61 inhibitors.
- Screening for small molecules that inhibit PD-L1 protein expression by interfering with ER translocation.
Main Results:
- Successfully developed the RELITE assay for single-round screening of Sec61 inhibitors.
- Identified small molecules that impede PD-L1 protein expression by disrupting ER translocation.
- Demonstrated the assay's capability to select inhibitors that promote degradation of target proteins.
Conclusions:
- The RELITE assay provides a powerful tool for selecting Sec61 inhibitors.
- This method facilitates the identification of compounds for down-modulating disease-relevant protein expression.
- The developed assay will accelerate the discovery of novel therapeutics for various pathologies.
