Related Experiment Video
Updated: Aug 10, 2025
High-throughput Screening for Small-molecule Modulators of Inward Rectifier Potassium Channels
Published on: January 27, 2013
Thimerosal, a competitive thioredoxin reductase 1 (TrxR1) inhibitor discovered via high-throughput screening
Yicheng Ni1, Zhongyuan Luo2, Yixin Lv3
1School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China; Drug Discovery and Design Center, The Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
Abstract:
Thioredoxin reductase 1 (TrxR1) is considered as an important anti-cancer drug target, inhibition of which can induce reactive oxygen species (ROS)-mediated apoptosis of human cancer cells. Here, we developed and optimized a high-throughput screening (HTS) assay based on enzyme kinetics for the discovery of TrxR1 inhibitors. By utilizing this assay, we performed a HTS for 2500 compounds from an in-house library against TrxR1. We found that a vaccine preservative, thimerosal, strongly inhibited TrxR1 in a competitive and reversible manner with an IC50 of 24.08 ± 0.86 nM. In addition, we determined that thiomersal has an inhibitory effect on the proliferation of A549 lung cancer cell line, with a GI50 of 6.81 ± 0.09 μM, slightly more potent than auranofin (GI50 = 11.85 ± 0.56 μM). Furthermore, we showed by flow cytometer that thimerosal effectively increased the content of ROS in A549 cells. Therefore, our work provided a high-throughput screening assay to quickly and effectively discover TrxR1 inhibitors, identifying thiomersal as a novel TrxR1 inhibitor and chemical probe.
Insights
We developed a high-throughput screening assay to find thioredoxin reductase 1 (TrxR1) inhibitors. The vaccine preservative thimerosal was identified as a potent TrxR1 inhibitor, inducing cancer cell death via reactive oxygen species (ROS).
Area of Science:
- Biochemistry
- Pharmacology
- Cancer Biology
Background:
- Thioredoxin reductase 1 (TrxR1) is a key target in anti-cancer drug development.
- Inhibiting TrxR1 can trigger reactive oxygen species (ROS)-mediated apoptosis in cancer cells.
Purpose of the Study:
- To develop and optimize a high-throughput screening (HTS) assay for discovering TrxR1 inhibitors.
- To identify novel TrxR1 inhibitors and chemical probes for cancer research.
Main Methods:
- Enzyme kinetics-based high-throughput screening (HTS) assay development.
- Screening of 2500 compounds from an in-house library against TrxR1.
- In vitro enzyme inhibition assays (IC50 determination) and cell proliferation assays (GI50 determination) using A549 lung cancer cells.
- Flow cytometry to measure intracellular ROS levels.
Main Results:
- A novel HTS assay for TrxR1 inhibitors was successfully developed and optimized.
- Thimerosal, a vaccine preservative, was identified as a potent TrxR1 inhibitor (IC50 = 24.08 ± 0.86 nM) with competitive and reversible kinetics.
- Thimerosal demonstrated significant anti-proliferative effects on A549 lung cancer cells (GI50 = 6.81 ± 0.09 μM), outperforming auranofin.
- Thimerosal treatment led to a marked increase in intracellular ROS levels in A549 cells.
Conclusions:
- The developed HTS assay is effective for rapid discovery of TrxR1 inhibitors.
- Thimerosal is a novel, potent inhibitor of TrxR1 and a valuable chemical probe for cancer research.
- Thimerosal's anti-cancer activity is mediated through ROS induction, highlighting its therapeutic potential.
