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Measurement of Drug-Stabilized Topoisomerase II Cleavage Complexes by Flow Cytometry
Marcelo de Campos Nebel1, Micaela Palmitelli1, Marcela González-Cid1
1Laboratorio de Mutagénesis, Instituto de Medicina Experimental (IMEX), Academia Nacional de Medicina, CONICET. Ciudad Autónoma de Buenos Aires, Argentina.
Abstract:
The poisoning of Topoisomerase II (Top2) has been found to be useful as a therapeutic strategy for the treatment of several tumors. The mechanism of Top2 poisons involves a drug-mediated stabilization of a Top2-DNA complex, termed Top2 cleavage complex (Top2cc), which maintains a 5' end of DNA covalently bound to a tyrosine from Top2 through a phosphodiester group. Drug-stabilized Top2cc leads to Top2-linked-DNA breaks, which are believed to mediate their cytotoxicity. Several time-consuming or cell type-limiting assays have been used in the past to study drug-stabilized Top2cc. Here, we describe a flow cytometry-based method that allows a rapid assessment of drug-induced Top2cc, which is suitable for high throughput analysis in almost any kind of human cell. The analyses of the drug-induced Top2cc in the cell cycle context and the possibility to track its removal are additional benefits from this methodology. © 2017 by John Wiley & Sons, Inc.
Insights
A new flow cytometry method rapidly assesses Topoisomerase II (Top2) poisons, which stabilize Top2-DNA complexes. This technique aids cancer therapy research by enabling high-throughput analysis of drug-induced Top2 cleavage complexes (Top2cc) in human cells.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Topoisomerase II (Top2) poisons are valuable cancer therapeutics.
- These poisons stabilize Top2-DNA complexes, forming Top2 cleavage complexes (Top2cc).
- Stabilized Top2cc leads to DNA breaks, mediating cytotoxicity.
Purpose of the Study:
- To develop a rapid, high-throughput method for assessing drug-induced Top2cc.
- To overcome limitations of existing time-consuming and cell-type-specific assays.
- To enable analysis of Top2cc within the cell cycle context.
Main Methods:
- A novel flow cytometry-based assay was developed.
- The method allows for rapid assessment of drug-induced Top2cc.
- The assay is suitable for high-throughput analysis in various human cell types.
Main Results:
- The flow cytometry method provides a fast assessment of Top2cc.
- The assay is adaptable to almost any human cell type.
- The methodology allows for cell cycle analysis and tracking of Top2cc removal.
Conclusions:
- The developed flow cytometry assay is an efficient tool for studying Top2 poisons.
- This method facilitates high-throughput screening of potential Top2-targeting cancer drugs.
- It offers advantages for understanding Top2cc dynamics and cytotoxicity mechanisms.
