DNA repair and resistance to topoisomerase I inhibitors: mechanisms, biomarkers and therapeutic targets

Alagoz, M., Gilbert, D.C., El-Khamisy, S. and Chalmers, A. (2012) DNA repair and resistance to topoisomerase I inhibitors: mechanisms, biomarkers and therapeutic targets. Current Medicinal Chemistry, 19(23), pp. 3874-3885. (doi: 10.2174/092986712802002590)

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Publisher's URL: http://dx.doi.org/10.2174/092986712802002590

Abstract

Irinotecan and topotecan are derivatives of the naturally occurring cytotoxic compound camptothecin that are used in the treatment of patients with colorectal cancer, either as single agents or in combination with radiotherapy and/or other chemotherapy drugs. They are inhibitors of DNA topoisomerase I (Top I) and exert their cytotoxic effects in replicating cells by inducing DNA strand breaks. A wide range of DNA repair proteins is involved in the recognition and repair of these breaks, and depletion or inhibition of some of these proteins increases the cytotoxic effects of Top I inhibitors. Building on these laboratory observations, ongoing translational research is aiming to establish whether this mechanistic information can be used to improve the treatment of patients with certain types of cancer. Two potential strategies are under investigation: (1) individualising treatment by evaluating levels and/or patterns of expression of DNA repair proteins that predict clinical response to Top I inhibitors, and (2) developing small molecule inhibitors of these repair enzymes to overcome tumour resistance and improve outcomes. This review summarises the current status of these research endeavours, focusing on the key roles of tyrosyl DNA phosphodiesterase 1 (Tdp1) and poly(ADP-ribose) polymerase (PARP), and examines the pre-clinical and clinical data that support the potential value of these and other DNA repair proteins as predictive markers and therapeutic targets. Since irinotecan is increasingly being combined with radiotherapy, the potential for these proteins to act as predictive biomarkers for both Top I inhibitors and radiation is proposed, and the possibility of synergistic potentiation of chemoradiation regimes by Tdp1 and/or PARP inhibitors is considered.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Chalmers, Professor Anthony
Authors: Alagoz, M., Gilbert, D.C., El-Khamisy, S., and Chalmers, A.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:Current Medicinal Chemistry
Publisher:Bentham Science Publishers Ltd.
ISSN:0929-8673
ISSN (Online):1875-533X
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
563531Overcoming treatment resistance in glioblastoma multiforme by tumour specific inhibition of DNA repairAnthony ChalmersMedical Research Council (MRC)G0802755ICS - PATHOLOGY
563532Overcoming treatment resistance in glioblastoma multiforme by tumour specific inhibition of DNA repairAnthony ChalmersMedical Research Council (MRC)G0802755ICS - PATHOLOGY