Organotellurium Reagents for Multiparametric Interrogation of Dynamic Biology

Population-averaged measurements (PAMs) of cells have advanced understanding of innumerable biochemical processes and continue to be routinely used in the laboratory. Despite this success, PAMs are limited in their ability to report on the precise state of important individual members of a population. The recent emergence of mass cytometry (MC) has offered a new solution to this problem: the ability to simultaneously measure a large number of parameters on a single cell. Unlike traditional fluorescence-based flow cytometry, which suffers from spectral overlap of fluorophore reporters, MC allows for simultaneous measurement of a massive number of parameters—limited only by the number of unique heavy isotopes on the periodic table. Since its inception, MC has relied on high molecular weight metal-chelating polymer antibody-conjugates (MCPACs) to quantify meaningful static biomarkers. Although very useful, MCPACs are unable to report on active biochemical processes. In response to this limitation, we have developed a modular, bio-compatible organotellurium “tag” with a mass less than 250 Da that can be incorporated into a variety of activity-based scaffolds. The work presented in this thesis outlines our efforts to develop a MC-compatible activity-based probe using this tag that is able to report on cancer cell oxygenation levels. We demonstrate that this molecule can be used to discriminate single cells based on their exposure to oxygen, both in vitro and in vivo. By synthesizing “isotopologous” variants of this probe (molecules that are structurally identical but differ in mass) and administering them to human pancreatic tumour models in a temporally-spaced dosing regime, we demonstrate that tumour microenvironments experiencing temporal fluctuations in oxygenation can be highlighted reliably at the single cell level for the first time. By coupling this approach with recently developed imaging mass cytometry technology, we present multiplexed images of specific regions within pancreatic tumours that exhibit fluctuating hypoxia with spatiotemporal resolution.

Department dc:contributor.department

Chemistry

Year dc:date.issued

2016

Author dc:creator

• Edgar, Landon John G.

Advisor dc:contributor.advisor

• Nitz, Mark

• Cancer
• Dynamic biology
• Hypoxia
• Isotopologues
• Mass cytometry
• Tellurium

Handle dc:identifier.uri

http://hdl.handle.net/1807/80383

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/80383