figshare
Browse
2017HAYWARDGMPhD.pdf (5.09 MB)

Investigating the Adverse Effects of Novel Tumour-Specific IAP Antagonists

Download (5.09 MB)
thesis
posted on 2017-09-04, 11:59 authored by Giles Mortimer Hayward
Inhibitor of apoptosis (IAP) proteins are negatively regulated by the mitochondrial pro-apoptotic protein, SMAC, through a tetrapeptide binding-motif. A class of drugs mimicking this motif have been developed as anti-cancer agents and have further highlighted IAP signalling in regulation of cell death. These SMAC mimetics (SMs) activate the non-canonical NF-κB pathway, induce TNFα secretion and selectively promote cell death in tumour cells; an effect potentiated in a TNFα-rich microenvironment. However, due to this mechanism of action, SMs have the potential to induce toxicity in non-tumour cells residing in this environment. The aim of this thesis was two-fold: to determine the effect of SMs in non-tumour derived cells both in vitro and in vivo. I determined a robust methodology in sensitive and resistant tumour cells with SMs as single agents. I found that MDA-MB-231 and MDA-MB-468 cells were sensitive and resistant to SMs as single agents, respectively. Furthermore, the pan caspase inhibitor, zVAD, actually inhibited TNFα secretion in combination with the bivalent SM, BV6. In hepatocyte-like and epithelial non-tumour cells in vitro, I found that SMs did not induce cell death, even when co-treated with TNFα. These data suggest that SMs under clinical development do not have significant toxicity in non-tumour derived cells suggesting a large therapeutic window in the clinic. As liver regeneration is also TNFα-dependent, SMs have the potential to exacerbate liver injury. To determine whether the SM, TL-32711, could induce NF- κB activation in vivo, I used mice expressing an NF-κB reporter gene (miceluc) allowing for quantification of NF-κB activity via in situ live imaging. Miceluc were dosed with TL-32711, either alone, or in combination with two hepatotoxins. Strikingly, TL-32711 alone induced significant liver-specific NF-κB activation and protected against liver injury. These data show that SMs could have real clinical relevance for use as a treatment to ameliorate hepatoxicity.

History

Supervisor(s)

MacFarlane, Marion

Date of award

2017-06-30

Author affiliation

MRC Toxicology Unit

Awarding institution

University of Leicester

Qualification level

  • Doctoral

Qualification name

  • PhD

Language

en

Usage metrics

    University of Leicester Theses

    Categories

    Keywords

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC