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An evaluation of 6-thioguanine derivatives as potential anti-cancer agents

Dissertation (MSc)--University of Pretoria, 2009.

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Other Authors: Van Rensburg, Connie E.J.
Format: Thesis
Published: University of Pretoria 2013
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access_status_str Open Access
author2 Van Rensburg, Connie E.J.
author_browse Van Rensburg, Connie E.J.
author_facet Van Rensburg, Connie E.J.
collection Thesis
dc_rights_str_mv © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc)--University of Pretoria, 2009.
format Thesis
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institution University of Pretoria (South Africa)
last_indexed 2026-06-10T12:37:36.202Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2013
publishDateRange 2013
publishDateSort 2013
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/29834 An evaluation of 6-thioguanine derivatives as potential anti-cancer agents Van Rensburg, Connie E.J. selma.burmeister@quintiles.com Samuels, Caroline Selma 6-thioguanine derivatives Antimetabolites UCTD Dissertation (MSc)--University of Pretoria, 2009. During neoplastic development cellular requirements for the micronutrients and macronutrients increase dramatically for the primary metabolites, sugar and amino-acids. This concept of increased cellular needs lead to the development of antimetabolites as anticancer agents. Antimetabolites, are structurally similar to that of physiological metabolites, but have the ability to interfere with normal metabolic functioning of the cell that eventually leads to cell death. One such agent used in chemotherapy is 6-thioguanine. Another group of agents that also only recently showed potential for the used in cancer therapy are the Au containing anti-arthritic gold compounds, such as Auranofin. Both these groups, antimetabolites and Au containing compounds have different intracellular targets e.g. DNA(6-Thioguanine) and thioredoxin reductase [Au(I) and Au(III)], respectively. No study thus far has attempted to combine gold to 6-thioguanine nor has it been tested on non-cancerous and cancer cell lines. In this study two novel Au(I) compounds were synthesized i.e. a Au (I) metal 6-thioguanine (EKJC56) compound and Au (I)-phoshine 6-thioguanine (EKJC80A) compound (Figure 1). The cytotoxic effect and selectivity of these novel compounds were determined on several cancerous and normal cell cultures using the MTT assay. The cells were exposed to varying concentrations of these compounds. The novel compounds (EKJC56ST, EKJC56, and EKJC80A) showed higher toxicity towards all the cancerous cell lines tested, while EKJC56ST and EKJC56 showed only slight inhibition of the proliferation of normal cell cultures. These novel compounds proved to be more selective towards the hormone dependent cell line compared to the non-hormonal cell lines. The Au-phoshine compound, EKJC80A were non selective for both cancerous cells and normal cell cultures. The mechanism of action of these compounds were evaluated and showed a higher percentage of induction early apoptosis compared to an untreated control group. These results were supported when the effect of these derivatives were evaluated on the activation of caspase-3 activity, a known marker of early apoptosis. On evaluation of the effect of these compounds on the mitochondrial membrane it was observed that the mitochondrial membrane of the HeLa cell line became hyperpolarized, but did not prove to be statistical significant. No significant changes in cell cycle phases were observed when cell cycle progression was investigated. Due to limited amounts of thioredoxin reductase enzyme an observational study was conducted to determine the possible involvement of the Au(I) side chain of the novel compounds on the functionality of this enzyme. It was observed that these novel Au(I) containing compounds were as effective as Auranofin to inhibit this enzyme at a concentration as low as 0.1ìM. Further enzymatic studies are still required to support the hypothesis. This study can assist in developing new multi-acting chemotherapeutic drugs that may have the potential to effectively and selectively treat cancer and minimize the development of resistance during treatment. Pharmacology unrestricted 2013-09-07T16:52:51Z 2009-12-11 2013-09-07T16:52:51Z 2009-09-01 2009-12-11 2009-11-26 Dissertation Samuels, CS 2008, An evaluation of 6-thioguanine derivatives as potential anti-cancer agents, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/29834 > E1443/ag http://hdl.handle.net/2263/29834 http://upetd.up.ac.za/thesis/available/etd-11262009-174642/ © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle 6-thioguanine derivatives
Antimetabolites
UCTD
An evaluation of 6-thioguanine derivatives as potential anti-cancer agents
title An evaluation of 6-thioguanine derivatives as potential anti-cancer agents
title_full An evaluation of 6-thioguanine derivatives as potential anti-cancer agents
title_fullStr An evaluation of 6-thioguanine derivatives as potential anti-cancer agents
title_full_unstemmed An evaluation of 6-thioguanine derivatives as potential anti-cancer agents
title_short An evaluation of 6-thioguanine derivatives as potential anti-cancer agents
title_sort evaluation of 6 thioguanine derivatives as potential anti cancer agents
topic 6-thioguanine derivatives
Antimetabolites
UCTD
url http://hdl.handle.net/2263/29834
http://upetd.up.ac.za/thesis/available/etd-11262009-174642/