Graduation Date

Fall 12-17-2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Cancer Research

First Advisor

Aaron Mohs

Abstract

Pancreatic cancer (PDAC) is an extremely lethal disease with an overall survival rate of 10%. Surgery remains the only potentially curative treatment option, but resections are complicated by infiltrative disease, proximity of critical vasculature, peritumoral inflammation, and dense stroma. Surgeons are limited to tactile and visual cues to differentiate cancerous tissue from normal tissue. Furthermore, translating preoperative images to the intraoperative setting poses additional challenges for tumor detection, and can result in undetected and unresected lesions. Thus, PDAC has high rates of incomplete resections, and subsequently, disease recurrence. Fluorescence-guided surgery (FGS) has emerged as a method to improve intraoperative detection of cancer and ultimately improve surgical outcomes. Initial clinical trials have demonstrated feasibility of FGS for PDAC, but there are limited targeted probes under investigation for this disease, highlighting the need for development of additional novel biomarkers to reflect the PDAC heterogeneity. MUCIN16 (MUC16) is a glycoprotein that is overexpressed in 60-80% of PDAC, yet this biomarker has not been investigated for FGS of this disease. Therefore, the goal of this project was to develop a MUC16-targeted fluorescent probe for intraoperative identification of PDAC through optical surgical navigation.

This dissertation describes the development of the fluorescent antibody conjugate, termed AR9.6-IRDye800, from inception to translational efficacy and safety studies. Initial studies demonstrated that AR9.6 bound to MUC16 in vitro, and demonstrated that binding was retained after conjugation to the near-infrared dye, IRDye800. Subcutaneous and orthotopic mouse models of pancreatic cancer demonstrated that this conjugate could target MUC16-expressing pancreatic cancer in vivo, and could identify PDAC intraoperatively, with significantly higher tumor to background ratios as compared to a non-specific IgG control. Metastatic lesions were identified under AR9.6-IRDye800 guidance, and fluorescence localization was observed microscopically in resected primary tumors and metastatic lesions. To build on the translational potential of this imaging probe, a humanized variant of the AR9.6 fluorescent conjugate was developed and investigated. This conjugate, termed huAR9.6-IRDye800, showed equivalent binding properties to its murine counterpart. Using an optimized dye:protein ratio of 1:1, in vivo studies demonstrated high tumor to background ratios in MUC16-expressing tumor models, and delineation of tumors in a patient-derived xenograft model. Safety, biodistribution, and toxicity studies were conducted, and demonstrated that huAR9.6-IRDye800 was safe, did not yield evidence of histological toxicity, and was well tolerated in vivo.

The results from this work conclude that AR9.6-IRDye800 is an efficacious and safe imaging agent for identifying pancreatic cancer intraoperatively through fluorescence-guided surgery. Future studies will investigate additional large animal models, patient stratification, development of companion MUC16 diagnostics and theranostics, and further safety, toxicity and efficacy studies to enable clinical translation.

Supplemental Video 1 AR9.6 (1).mp4 (438 kB)
Orthotopic Pancreatic Cancer Resection under AR9.6-IRDye800 Guidance

Supplemental Video 2 IgG (1).mp4 (110 kB)
Orthotopic Pancreatic Cancer Resection Under Non-Specific IgG Control Guidance

Available for download on Sunday, September 24, 2023

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