Mechanistic Basis of Sensitivity/Resistance Towards Anti-Cancer Drugs Targeting Topoisomerase II
Abstract
Human topoisomerase Ila (hstopo Ila) is an essential enzyme that is the target of a number of anticancer drugs in clinical use, making the understanding of its catalytic mechanism very important. Clinically, resistance to anticancer drugs develops through various mechanisms, one of which can be found in a class of a typical multidrug resistant mutants (at-MDR) that has been identified. We will attempt to further clarify the biochemical basis of at-MDR among hstopo Ila mutants to shed more light on the topo II enzymatic mechanism. Additionally, we will identify sites of drug binding on hstopo Ila and the consequences of this action. To this end, we have probed the mechanism of hstopo Ila using cysteine footprinting and endoproteinase/mass spectrometry footprinting. With the cysteine footprinting technique, we have shown that menadione may induce conformational changes in hstopo Ila that cause it to remain in a configuration that is different from the wild-type populated state. Additionally, using an endoporteinase/mass spectrometry footprinting approach, we have located a potential cysteine residue on hstopo Ila that may be modified by menadione. These preliminary results provide the first direct evidence that menadione may act as an anticancer drug by binding to a specific position(s) on hstopo Ila causing it to adopt a conformation contrary to the wild-type form.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2004
- Accession Number
- ADA424021
Entities
People
- Tammy R. Collins
- Tao-shih Hsieh
Organizations
- Duke University