Publication Date

2008-05-02

Availability

Open access

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Biochemistry and Molecular Biology (Medicine)

Date of Defense

2007-06-05

First Committee Member

Paul Boehmer - Committee Chair

Second Committee Member

W. Dalton Dietrich, III - Committee Member

Third Committee Member

Richard Voellmy - Mentor

Fourth Committee Member

Stephen M. Roberts - Outside Committee Member

Abstract

Activated Heat Shock Transcription Factor 1 (HSF1) has received attention in recent literature as a therapeutic effector in diseases of protein misfolding, as an immune modulating adjuvant in tumor regression, and as a trigger for gene therapy transcription. In its normal function, activated HSF1 enhances heat shock protein (Hsp) expression when additional molecular chaperoning is required (i.e., in situations of proteotoxic stress, including thermal stress) in a process known as the heat shock (HS) response. Thus, HSF1 acts as an environmental sensor, and a harness based on the biology of this capability enables transcription of genes for engineered purposes. The hypothesis of this thesis is that a harness of the heat shock response, when paired with a therapeutic mechanism, will refine novel therapies. Extensions to the concept of deliberately activating HSF1's normal functions for therapeutic purposes are examined through in vitro trials and in vivo preliminary studies that feature the use of HSF1 as a regulator of therapy. Successful in vitro work translated to pioneering preclinical studies, launched at the University of Florida's Center for Environmental and Human Toxicology. Collaboration supported the development of an innovative project to treat solid tumors using a recombinant virus system. The system was designed to facilitate intratumoral delivery of a previously characterized molecular switch, which was newly engineered to control cytotoxic gene transcription that produced dramatic consequences in cells of human origin. Central to the targeting of the in vivo therapy, is a transient, initial trigger: a thermal dose, delivered to solid tumors, which localizes HSF1 activation (a constitutively active mouse HSF1 construct was also produced to aid clarification of physiological consequences associated with deliberately upregulating HSF1 activity in vivo). Gene transcription was expected to ensue to both cause and sustain tumor regression through other regulatory elements of the molecular switch. Results demonstrated practical potential to achieve a therapeutic outcome of solid tumor regression and define contemporary challenges that continuing research directions (e.g.: production of additional viral vectors, an improved animal model, and a refined heat system) now confront in order to target and safely regulate even more potent, novel therapeutic agents.

Keywords

GALV; SafeSwitch; Oncolytic Adenovirus; HT-1080; F98; Cancer; Implanted Subcutaneous

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