Doctor of Philosophy (PhD)
the Department of Chemistry
Fluorescence imaging can be used both as a tool to diagnose diseases and guide treatment in clinical settings, and as a technique to monitor dynamic events or biological species in basic research. Therefore, there is a great need for the development of a multitude of fluorescent probes that can be incorporated with fluorescence imaging techniques to track and report endogenous enzymes with high specificity and selectivity. In contrast to always-on and targeted always-on fluorescent probes that continually emit light, activity-based substrate probes either emit low numbers of photons or are completely quenched. They can be converted to highly fluorescent reporters by specific upregulated enzymes, thus offering a high target-to-background ratios contrast. Fluorescent probes have a promising impact in fluorescence-guided cytoreductive surgery, but complete resection in every patient is highly unlikely. Probes that emit near-infrared (NIR) light are more suitable for in vivo imaging. Therefore, in this work, hNQO1-activatable NIR imaging probes (Q3STCy and Q3NTCy) with different eliminating linker and different affinities for hNQO1 were developed. These probes were successful in imaging clinically relevant multicellular tumor spheroids (MCTSs) possessing spatially heterogeneous NQO1 activities and in identifying sub-millimeter dimension metastases in a preclinical mouse model of human ovarian serous adenocarcinoma. To further diversify the research, ratiometric probes (GalNap and CysTy) with the capability to quantify the enzyme beta-Galactosidase and cysteine were developed. GalNap was used in the real-time detection of beta-Galactosidase in human ovarian cancer cells and CysTy was used to detect cysteine in human plasma. As an initiative to contribute to effective cytoreductive surgery, a chemical agent (Q3Pyro) was designed and synthesized that can not only light up, but can also be toxic toward hNQO1-expressing tumor tissues. With various imaging and cell assays, the probe was validated to perform as both a profluorogenic probe and a prodrug.
Shen, Zhenhua, "Visualization and Quantification of Cancer-associated Enzymes with Fluorescent Small-molecule Substrate Probes" (2018). LSU Doctoral Dissertations. 4614.
McCarley, Robin L
Available for download on Sunday, June 13, 2021