TY - JOUR
T1 - Exploring the cellular activity of camptothecin-triple-helix-forming oligonucleotide conjugates
AU - Arimondo, Paola B.
AU - Thomas, Craig J.
AU - Oussedik, Kahina
AU - Baldeyrou, Brigitte
AU - Mahieu, Christine
AU - Halby, Ludovic
AU - Guianvarc'h, Dominique
AU - Lansiaux, Amélie
AU - Hecht, Sidney M.
AU - Bailly, Christian
AU - Giovannangeli, Carine
PY - 2006/1
Y1 - 2006/1
N2 - Topoisomerase I is a ubiquitous DNA-cleaving enzyme and an important therapeutic target in cancer chemotherapy for camptothecins (CPTs). These drugs stimulate DNA cleavage by topoisomerase I but exhibit little sequence preference, inducing toxicity and side effects. A convenient strategy to confer sequence specificity consists of the linkage of topoisomerase poisons to DNA sequence recognition elements. In this context, triple-helix-forming oligonucleotides (TFOs) covalently linked to CPTs were investigated for the capacity to direct topoisomerase I-mediated DNA cleavage in cells. In the first part of our study, we showed that these optimized conjugates were able to regulate gene expression in cells upon the use of a Photinus pyralis luciferase reporter gene system. Furthermore, the formation of covalent topoisomerase I/DNA complexes by the TFO-CPT conjugates was detected in cell nuclei. In the second part, we elucidated the molecular specificity of topoisomerase I cleavage by the conjugates by using modified DNA targets and in vitro cleavage assays. Mutations either in the triplex site or in the DNA duplex receptor are not tolerated; such DNA modifications completely abolished conjugate-induced cleavage all along the DNA. These results indicate that these conjugates may be further developed to improve chemotherapeutic cancer treatments by targeting topoisomerase I-induced DNA cleavage to appropriately chosen genes.
AB - Topoisomerase I is a ubiquitous DNA-cleaving enzyme and an important therapeutic target in cancer chemotherapy for camptothecins (CPTs). These drugs stimulate DNA cleavage by topoisomerase I but exhibit little sequence preference, inducing toxicity and side effects. A convenient strategy to confer sequence specificity consists of the linkage of topoisomerase poisons to DNA sequence recognition elements. In this context, triple-helix-forming oligonucleotides (TFOs) covalently linked to CPTs were investigated for the capacity to direct topoisomerase I-mediated DNA cleavage in cells. In the first part of our study, we showed that these optimized conjugates were able to regulate gene expression in cells upon the use of a Photinus pyralis luciferase reporter gene system. Furthermore, the formation of covalent topoisomerase I/DNA complexes by the TFO-CPT conjugates was detected in cell nuclei. In the second part, we elucidated the molecular specificity of topoisomerase I cleavage by the conjugates by using modified DNA targets and in vitro cleavage assays. Mutations either in the triplex site or in the DNA duplex receptor are not tolerated; such DNA modifications completely abolished conjugate-induced cleavage all along the DNA. These results indicate that these conjugates may be further developed to improve chemotherapeutic cancer treatments by targeting topoisomerase I-induced DNA cleavage to appropriately chosen genes.
UR - http://www.scopus.com/inward/record.url?scp=33645220275&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33645220275&partnerID=8YFLogxK
U2 - 10.1128/MCB.26.1.324-333.2006
DO - 10.1128/MCB.26.1.324-333.2006
M3 - Article
C2 - 16354702
AN - SCOPUS:33645220275
SN - 0270-7306
VL - 26
SP - 324
EP - 333
JO - Molecular and cellular biology
JF - Molecular and cellular biology
IS - 1
ER -