In the 1980's, Nicholas Farrell developed a range of structurally distinct multinuclear Pt complexes that form long-range interstrand crosslinks (IXLs) in DNA. The dinuclear complex [{trans-PtCl2(NH3)}2-µ-(H2N(CH2)6NH2)]2+ (1,1/t,t) was the first of this series to show promising results, however, it was the trinuclear complex [{trans-PtCl2(NH3)}2-µ-trans-Pt(NH3)2(H2N(CH2)6NH2)2]4+ (1,0,1/t,t,t or BBR3464) that was chosen for clinical trials based on significantly increased cytotoxicity compared to 1,1/t,t and cisplatin. Molecular biology experiments have shown that 1,1/t,t exclusively forms IXLs in DNA in the 5'¿ 5' direction, whilst 1,0,1/t,t,t can form IXLs in both the 5'¿5' and 3'¿3' directions. Previously, 2D [1H,15N] HSQC NMR has been used to study the formation of 5'5' 1,4GG IXLs. The formation of 3'3' 1,4GG IXLs have been studied as part of this thesis. More recently, Pt complexes such as [{transPtCl2(NH3)}2{H2N(CH2)6(NH2(CH2)2NH2)(CH2)6NH2}]4+ (1,1/t,t6,2,6) and [{transPtCl2(NH3)}2{H2N(CH2)6(NH2)(CH2)6NH2}]3+ (1,1/t,t6,6), where the charged central Pt moiety of 1,0,1/t,t,t is replaced by a polyamine linker, have been developed in the Farrell group and show increased potency compared to 1,0,1/t,t,t. The complex 1,1/t,t 6,2,6 is a lead candidate currently undergoing Phase I clinical trials. Prior to the work presented in this thesis, little was known about the aquation chemistry or kinetics of DNA binding of these novel complexes. Reported in Chapter 3 is the study of the formation of 3'3' 1,4GG IXLs by both 1,0,1/t,t,t and 1,1/t,t in the duplex 5' {d(TATACATGTATA)2} (3314XL) (pH 5.4, 298K). A combination of 1D 1H and 2D [1H, 15N] HSQC NMR experiments was used to directly compare the results with the stepwise formation of the 5'5' 1,4GG IXL with the previously studied duplex, 5' {d(ATATGTACATAT)2} (5514XL), under the same conditions. Preassociation as well as aquation were similar, however, differences were observed at the monofunctional binding step with evidence for numerous monofunctional adducts. Both reactions did not yield a single 3'3' 1,4GG IXL, rather several adducts that could not be characterised. Molecular dynamics simulations of the 3'3' 1,4GG IXLs showed highly distorted lesions that may have implication in cellular repair processes.
| Identifer | oai:union.ndltd.org:ADTP/279683 |
| Date | January 2010 |
| Creators | Ruhayel, Rasha A. |
| Publisher | University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Rasha A. Ruhayel, http://www.itpo.uwa.edu.au/UWA-Computer-And-Software-Use-Regulations.html |
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