Polyamines and their potential exploitation in drug delivery
thesisposted on 15.12.2014, 10:41 by Natalie Gail. Travis
The novel polyamine-conjugates synthesised and presented in this thesis were used to investigate the following; i) the structural specificity of the polyamine uptake system, ii) the intracellular location of polyamines and mechanism of uptake and iii) the proteins involved in the polyamine transport mechanism.;Synthetic methods were developed to synthesise N,N-dialkylated polyamines in high yields utilising the protecting group BOC, the phase transfer catalyst tetra-butylammonium hydrogen sulphate and an alkyl bromide. This methodology was used to synthesise a range of terminally ethylated polyamine-chlorambucil and polyamine-MANT conjugates. Synthetic procedures were also devised employing high dilution factors and an excess of spermine, to allow the selective protection of N1 on spermine with either a BOC or MANT group, thus providing routes for the synthesis of photoaffinity polyamine-conjugates.;The promising results obtained from competitive inhibition uptake studies and cytotoxicity studies for N1,N12-diethyl spermine-chlorambucil, in terms of low Ki and IC50 values coupled with the potential reduced neurotoxicity, suggest that this compound should undergo further investigation as a potential anticancer agent.;Confocal laser scanning microscopy images provided evidence that the diethyl polyamine- MANT conjugates and their parent conjugates were not associated with the nuclear DNA. The conjugates were observed in granular structures, non-uniformly distributed within the cytoplasm.;The novel, non-radioactive fluorescent photoaffinity polyamine-conjugate N1-MANT-N12-ASA spermine was used in an attempt to isolate the polyamine transport protein. Cultured cells treated with the conjugate were subsequently found to be fluorescent, suggesting a stable covalent linkage between the conjugate and the cells. Isolation and separation of the plasma membranes on a SDS-PAGE gel resulted in fluorescent bands being viewed at the running front of the gel.