Graduation Date

Spring 5-4-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Pharmaceutical Sciences

First Advisor

David Oupicky

Second Advisor

DJ Murry

Third Advisor

Tony Hollingsworth

Fourth Advisor

Sarah Thayer

Abstract

Hydroxyethyl starch (HES) is a clinically used polysaccharide colloidal plasma volume expander. The goal of this study was to synthesize HES modified with hydroxychloroquine (HCQ) as a novel polymeric drug with the ability to inhibit the invasive character of pancreatic cancer (PC) cells. HES was conjugated with HCQ using a simple carbonyldiimidazole coupling to prepare Chloroquine-modified HES (CQ-HES). CQ-HES with various degrees of HCQ substitution were synthesized and characterized. In vitro studies showed CQ-HES to have a similar toxicity profile as HCQ. Confocal microscopy revealed the propensity of CQ-HES to localize to lysosomes, and mechanistic studies confirmed the ability of CQ-HES to inhibit autophagy in PC cells similar to HCQ. Further studies demonstrated a greatly enhanced ability of CQ-HES to inhibit the invasion of PC cells when compared with HCQ. No significant HCQ release from CQ-HES was observed, which confirmed that the observed activity was due to the action of CQ-HES as a polymeric drug. Pharmacokinetic (PK) studies showed that CQ-HES preferentially distributed to the liver and kidney but had limited ability to alter distribution to tumors. Furthermore, levels observed in the eyes were 2-4 times higher when administering HCQ than CQ-HES. In an orthotopic syngeneic model of PC, the addition of CQ-HES to gemcitabine therapy reduced primary tumor growth and prolonged survival. Additionally, mice who received HCQ showed significantly higher levels of HCQ in the eyes compared to CQ-HES. Complete blood count and complete metabolic profiles did not identify any organ or tissue dysfunctions in mice receiving CQ-HES. Further pathohistological analysis confirmed the safety of CQ-HES as no microscopic indications of augmented tissue damage were observed. Lastly, pretreatment sensitization with CQ-HES improved survival in the setting of stereotactic body radiation therapy. Thus, CQ-HES appears to be safe, improves outcomes of radiation and chemotherapy, and reduces HCQ exposure to the eye, which may help prevent retinopathy.

Available for download on Friday, April 16, 2021

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