Despite significant advances in chemotherapeutics since their initial application in the early 1900s, cancer remains a leading cause of death worldwide. Furthermore, issues encountered with the first chemotherapeutics, off-target toxicity, limited effective dosing time in the therapeutic window, multidrug resistance, and poor uptake in solid tumors persist today. This dissertation investigates two platforms to enhance chemotherapy efficacy, an implantable drug delivery depot affording tumor drug levels unachievable through systemic delivery, and a platform utilizing CRISPR knockout screening (CRISPRKO) to identify microRNA (miRNA) targets that synergize with chemotherapeutics using RNA interference (RNAi).
First, we developed a flexible, implantable surgical buttress coated with a free and covalently-bound paclitaxel polymer blend with poly(1,2-glycerol carbonate)-graft-succinic acid-paclitaxel (PGC-PTX). Drug release is tunable
between burst release of free paclitaxel and delayed, extended release of paclitaxel from PGC-PTX, delivering supratherapeutic levels of PTX locally at the tumor resection bed while avoiding systemic toxicity. Fabrication of paclitaxel-loaded film is scalable up to 8”x11” and well-tolerated in a porcine model wherein surgical technique and optimized film formulations reduce foreign body response and bowel adhesions. We test a similarly-designed film formulation with the novel chemotherapeutic, eupenifeldin, for treatment of lung cancer. Eupenifeldin-loaded films significantly prolong mice survival, although 60% of mice present issues with drug-related toxicity and wound healing.
Second, despite the formidable ability of pooled CRISPRKO libraries to screen thousands of single-gene knockouts against a selection agent, minimal has been published on their use to determine novel targets for RNAi-based sensitization of chemotherapeutics. We utilize whole-genome CRISPRKO screening against a panel of lung cancers to identify miRNAs capable of synergizing with paclitaxel as well as two novel chemotherapeutics, eupenifeldin and verticillin A. Identified targets are validated for synergy with their respective chemotherapeutic in vitro, demonstrating a 50% or greater increase in cell death compared to drug-only treatment. In summary, this work presents two successful treatment platforms that address key issues preventing translation of chemotherapeutics to the clinic: 1) dose-limiting toxicity and 2) limited efficacy with poor safety/benefit ratio. Implantable, drug-loaded films serve as a platform to deliver increased doses of chemotherapeutic to tumor while avoiding off-target toxicity. As a second platform, we enhance tumor-specific chemotherapy efficacy utilizing miRNA targets identified in a CRISPRKO screening pipeline.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/46652 |
| Date | 30 August 2023 |
| Creators | Korunes-Miller, Jenny Taylor |
| Contributors | Grinstaff, Mark W. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution-NonCommercial-ShareAlike 4.0 International, http://creativecommons.org/licenses/by-nc-sa/4.0/ |
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