| dc.description.abstract | The design and development of fluorescent reporters focussed on highly sensitive,
specific, and selective imaging of cancer targets is described. These novel optical
molecular probes were synthesised with the aim of creating bio-imaging breakthroughs
that will aid the clinical analysis of cancer. A specific target of the project was to
develop fluorescent reporters for Caspases; intracellular endopeptidases that play an
essential role in apoptosis. Lack of activation of the ‘Caspase Cascade’ causes
uncontrolled proliferation of cells and has been deemed a ‘Hallmark of Cancer’. In
particular, low Caspases-3/7 activities have been associated with a range of cancers,
thus molecular detection of Caspases-3/7 activities could therefore lead to advances in
oncology.
A 14-member FRET library, based upon Caspases-3/7 specific peptide sequences, was
initially developed. The cleavage rates and KM values were evaluated for Caspases-3/7,
along with the cleavage rates for Cathepsin B, to determine the peptide with the
greatest affinity and specificity for Caspase-3. Also developed was a set of internally
quenched activity based molecular reporters constructed by attaching fluorophores to
a tribranched dendron through the Caspase specific peptide, developed from the FRET
Library. The KM values of the dendron probes with Caspase-3 were also evaluated.
Furthermore, the dendron reporters were attached to cell penetrating peptides to
enable delivery to intracellular Caspase and allow in situ detection of activated
Caspase-3 within live cells.
In addition, a new labelling moiety was developed enabling dual detection of reporters
through fluorescence and MRI imaging. To achieve this, a perfluoro tag (C8F17) was
tethered to a Cy5 dye to enable dual detection. The dual 19F-MRI/Cy5 dye was
conjugated onto to a cell penetrating peptide to enable in vivo detection of the probe by
19F-MRI and fluorescent imaging. | en |
