Abstract
Oncogene dysregulation is a driver of neoplasia development and progression. The use of quantitative molecular imaging to quantify oncogene activation will be crucial in developing companion diagnostics which can identify personalised patient regimens. However, the evaluation of oncogene activation does not necessarily correlate with oncoprotein activation. Post-translational modifications, such as phosphorylation, lipidation and methylation, may enhance oncoprotein functionality. It is this functionality that progresses neoplasia and may correlate with patient outcome. Advanced molecular imaging may be used to directly quantify oncoprotein, as opposed to oncogene, activation. Time-resolved Förster Resonance Energy Transfer (TR-FRET) involves the non-radiative transfer of energy from one chromophore to another over distances of 1-10 nm; allowing FRET to be used as a “chemical ruler”. TR-FRET can be utilised to directly elucidate spatial oncoprotein activation in single cells and patient tissues. In single cells, TR-FRET has uncovered the mechanisms by which PKCβ1 is trafficked to the nucleus and cleaved. Additionally it has revealed the mechanism of activation of Akt/PKB, whereby Akt/PKB undergoes a conformational change, allowing the Thr308 site to be phosphorylated by PDK1. Moreover TR-FRET has been utilised to quantify HER2-HER heterodimerisation and Akt/PKB activation states in patient biopsies, where it is shown to be predictive of outcome/relapse. The role of TR-FRET is not solely limited to intracellular signalling events. A study has used TR-FRET to measure intercellular immune-checkpoint receptor-ligand interactions. Within this study it was seen that PD-L1 expression was not indicative of PD-1/PD-L1 interaction states in a range of solid tumours. Crucially, in melanoma and NSCLC, PD-1/PD-L1 interaction was a predictive of an improved patient outcome. PD-L1 expression did not predict patient outcome. Several groups have worked to improve Fluorescence lifetime imaging microscopy (FLIM) acquisition times, including the use of: window-galvanometers; multifocal multiphoton FLIM and parallel pixel excitation coupled with wide-field time-gated FLIM. The development of novel quantitative molecular imaging will be critical in the development of personalised patient therapies in the future.
Original language | English |
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Article number | 106768 |
Journal | Biophysical Chemistry |
Volume | 283 |
Early online date | 29 Jan 2022 |
DOIs | |
Publication status | Published - 30 Apr 2022 |
Bibliographical note
Funding Information:We are most grateful to Professor Peter J Parker and the many years of his fruitful collaboration and discussions with our teams. We thank Professor Stephen G Ward for his continuous scientific discussions and advice. We also thank Dr. Véroniqe Calleja, Dr. Lissete Sánchez-Magraner and Christopher J Applebee (BSc, MSc) for their crucial work which has led into the results discussed in this review. Lastly, we are grateful to Pierre Leboucher (Eng.) for the initial and continued development of the semi-automated high-throughput image acquisition platform that was utilised in Veeriah et al., 2014, Miles et al., 2017 and Sánchez-Magraner and Miles et al., 2020. Figs. 1-5 and the graphical abstract were created using BioRender. The work reviewed from the manuscript, Sanchez-Magraner et al., 2020, was in part funded by the Bikaintek grant for industrial doctorates in the Basque Country. The work reviewed from Miles et al., 2017 acknowledges the funding from the Spanish Ministry of Economy for the grants (grant number BFU 2011-28566 ) and Basque Government through the BERC 3602014–2017 ; the Spanish Ministry of Economy and Competitiveness (MINECO) .
Keywords
- Acceptor
- Activation State
- Chromophore
- Donor
- FLIM
- FRET
- Oncoprotein
- Spatiotemporal
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Organic Chemistry