Chemical biology studies on 5-nitrofurans and sirtuin inhibitors
Abstract
Part I: Target identification studies are one of the most difficult but rewarding challenges in
chemical biology. Part I of this thesis describes target identification studies for 5-nitrofuran
containing hits. The 5-nitrofurans used in this study were identified in a phenotypic screen for
compounds that induced melanocyte cells death in zebrafish.
Chapter 1 provides brief overviews on three related areas of the project: 1) the use of
zebrafish as a model organism in drug discovery; 2) phenotypic screening using zebrafish and
3) the strategies used in target identification studies.
Chapter 2 describes the synthesis of and SAR studies on two series of 5-nitrofuran
containing analogues. The design and preparation of biotinylated chemical probes based on
the SAR data is also described. These chemical tools are then used in affinity
chromatography studies and genetic validation of a potential target (zebrafish Aldh2) of the
5-nitrofuran compounds is reported.
Chapter 3 provides a review of the biological and chemical processes that human ALDHs
are known to mediate. In addition, small molecules that modulate ALDH2 activity are
reviewed. A detailed study of the interaction between 5-nitrofurans and human ALDH2
including in vitro enzymatic assays is described leading to the conclusion that the 5-
nitrofurans under study are substrates of human ALDH2. Further mechanism of action
investigations using model reactions are also presented.
Chapter 4 introduces the use of 5-nitrofuran containing drugs in the clinic and highlights the
reported side-effects. Further investigation of the interaction between ALDH2 and 5-
nitrofurans in zebrafish and yeast using ALDH2 inhibitors is described. Based on these
results, a combination therapy strategy is proposed. Finally, the trypanocidal activity of the
newly synthesised 5-nitrofurans is discussed.
Experimental details and future work for Part I are presented in Chapters 5 and 6
respectively.
Part II: Human sirtuins are associated with various biological functions and diseases,
including cancer and neurodegeneration. Previous work from the Westwood Lab has led to
the discovery of the tenovins that act as inhibitors of SIRT1 and SIRT2. Part II of the thesis
reports the development of potent fixed ring tenovin analogues with high SIRT2 selectivity.
Chapter 7 provides a brief review of the biology of human SIRT2 and the reported SIRT2
inhibitors available to date. This is followed by a short summary of the previous work on the
tenovins in the Westwood Lab and the design of the fixed ring tenovin analogues.
Chapter 8 describes the synthesis of three series of fixed ring tenovin analogues. SAR data is
generated based on in vitro enzymatic assays against both SIRT1 and SIRT2 and the prepared
analogues showed relatively high potency and selectivity against SIRT2. Further cell-based
deacetylation assay are also discussed. All the experimental details are reported in Chapter 9
and Chapter 10 provides with conclusions and proposed future work.
Type
Thesis, PhD Doctor of Philosophy
Rights
Embargo Date: 2020-04-25
Embargo Reason: Thesis restricted in accordance with University regulations. Print and electronic copy restricted until 25th April 2020
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