Open Access. Powered by Scholars. Published by Universities.®
- Keyword
Articles 1 - 2 of 2
Full-Text Articles in Medicine and Health Sciences
Enzyme Architecture And Flexibility Affect Dna Topoisomerase I Function, Mariè Van Der Merwe
Enzyme Architecture And Flexibility Affect Dna Topoisomerase I Function, Mariè Van Der Merwe
Theses and Dissertations (ETD)
DNA topoisomerase I (Top1) is a highly conserved enzyme composed of four domains: a positively charged N-terminus; a DNA binding/core domain that circumscribes duplex DNA; a non-conserved linker domain; and a C-terminal/catalytic domain. Top1 catalyzes changes in DNA topology by transient cleavage of a single DNA strand and the concomitant formation of a phosphotyrosyl linkage between the enzyme and the 3’ DNA end. This covalent Top1-DNA complex is the binding site for camptothecin (CPT), which selectively inhibits religation of the cleaved DNA strand. CPT binding stabilizes the covalent complex, while the collision of replication forks with CPT-Top1-DNA adducts produces DNA …
The Role Of Multi-Drug Resistance Associated Protein 4 And P-Glycoprotein In Resistance Of Neuroblastoma To Topotecan And Irinotecan, Patricia Kellie Turner
The Role Of Multi-Drug Resistance Associated Protein 4 And P-Glycoprotein In Resistance Of Neuroblastoma To Topotecan And Irinotecan, Patricia Kellie Turner
Theses and Dissertations (ETD)
High-risk neuroblastoma presents a significant therapeutic challenge because the 5-year survival rate remains less than 30% despite the use of surgery, multi-agent chemotherapy, radiation, and autologous bone marrow transplant. Novel therapeutic modalities are under development. The camptothecin analogs topotecan and irinotecan have been identified as successful cytotoxic agents. For topotecan, pharmacokinetically guided dosing to achieve a systemic exposure associated with preclinical anti-tumor activity in neuroblastoma xenograft models is feasible and has elicited favorable responses in children with high-risk neuroblastoma. However, some children with high-risk disease did not respond to the putatively effective topotecan systemic exposure. These children represent a subset …