Related Experiment Video
Updated: Apr 1, 2026
Assessment of Global DNA Double-Strand End Resection using BrdU-DNA Labeling coupled with Cell Cycle Discrimination Imaging
Published on: April 28, 2021
A ROS-Activatable Agent Elicits Homologous Recombination DNA Repair and Synergizes with Pathway Compounds
Fathima Shazna Thowfeik1, Safnas F AbdulSalam1, Mark Wunderlich2
1Department of Chemistry, University of Cincinnati, 404 Crosley Tower, Cincinnati, OH, 45221-0172, USA.
Abstract:
We designed ROS-activated cytotoxic agents (RACs) that are active against AML cancer cells. In this study, the mechanism of action and synergistic effects against cells coexpressing the AML oncogenes MLL-AF9 fusion and FLT3-ITD were investigated. One RAC (RAC1) had an IC50 value of 1.8±0.3 μm, with ninefold greater selectivity for transformed cells compared to untransformed cells. Treatment induced DNA strand breaks, apoptosis, and cell cycle arrest. Proteomics and transcriptomics revealed enhanced expression of the pentose phosphate pathway, DNA repair, and pathways common to cell stress. Western blotting confirmed repair by homologous recombination. Importantly, RAC1 treatment was synergistic in combination with multiple pathway-targeting therapies in AML cells but less so in untransformed cells. Together, these results demonstrate that RAC1 can selectively target poor prognosis AML and that it does so by creating DNA double-strand breaks that require homologous recombination.
Insights
Researchers developed novel ROS-activated cytotoxic agents (RACs) that selectively target acute myeloid leukemia (AML) cells. RAC1 induces DNA damage and apoptosis, showing promise as a targeted AML therapy.
Area of Science:
- Oncology
- Molecular Biology
- Drug Discovery
Background:
- Acute myeloid leukemia (AML) is a heterogeneous cancer with poor prognosis.
- Targeted therapies are needed to overcome resistance and improve outcomes.
- Reactive oxygen species (ROS) are implicated in AML pathogenesis.
Purpose of the Study:
- To design and evaluate ROS-activated cytotoxic agents (RACs) against AML cells.
- To investigate the mechanism of action and synergistic effects of RAC1 in AML.
- To assess the selectivity and therapeutic potential of RAC1 in AML.
Main Methods:
- Synthesis and characterization of RACs.
- In vitro cytotoxicity assays (IC50 determination).
- Flow cytometry for apoptosis and cell cycle analysis.
- Proteomics, transcriptomics, and Western blotting for mechanistic studies.
- Combination therapy studies with pathway-targeting agents.
Main Results:
- RAC1 demonstrated potent activity against AML cells with an IC50 of 1.8±0.3 μm.
- RAC1 exhibited ninefold greater selectivity for transformed AML cells over untransformed cells.
- Treatment induced DNA strand breaks, apoptosis, and cell cycle arrest.
- Mechanistic studies revealed enhanced pentose phosphate pathway and DNA repair (homologous recombination) activity.
- RAC1 showed synergistic effects when combined with other AML therapies.
Conclusions:
- RAC1 is a promising ROS-activated cytotoxic agent for targeting poor-prognosis AML.
- RAC1 selectively induces DNA double-strand breaks requiring homologous recombination for repair in AML cells.
- RAC1 exhibits synergistic effects with existing AML therapies, suggesting its potential in combination treatment strategies.
Related Concept Videos
02:31Homologous Recombination
02:31Homologous Recombination
02:25Overview of DNA Repair
02:25Overview of DNA Repair
Chemically...
01:08Nucleotide Excision Repair
01:38Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...