Kawabe, Mayumi
(2009)
DEVELOPING COMBINATIONAL IMMUNOTHERAPIES TARGETING TUMOR RECEPTOR TYROSINE KINASES.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Current immunotherapies designed to stimulate specific T cell-mediated immunity have thus far yielded modest objective clinical response rates, despite the increase of tumor-specific T cells have been observed in treated patient blood. Since the majority of tumor antigens being targeted in immunotherapies are non-mutated, "self" antigens, current clinical results may relate, in part, to the low-to-moderate avidity, negatively-selected T cell repertoire in patients that is being asked to regulate tumor progression. In the current thesis, I hypothesized that by conditionally enhancing the proteasomal degradation of tumor antigens, I could generate a "synchronized" pool of derivative peptides that could then be presented in a "wave-like" temporal fashion in MHC class I complexes on the tumor cell surface. For at least a transient period thereafter, I theorized that specific CD8+ T cell recognition and anti-tumor activities would be improved. I selected a family of tumor-associated antigens, receptor tyrosine kinases (RTK) for study, as their overexpression has been linked with poor clinical prognosis in many forms of cancer. In this thesis, I show that EphA2 agonists, as well as, HSP90 inhibitors effectively promote EphA2 degradation via a proteasome- dependent manner, providing the delivery of EphA2 peptides into the classical MHC class I presentation pathway. I also show that specific CD8+ T cell recognition of EphA2 peptides derived from both the extracellular and intracellular domains of this transmembrane protein was improved as a consequence of tumor cell treatment with these agents being in consistent with the use of TAP- and ER-associated degradation. Notably, the combination of both drugs further enhanced anti-EphA2 T cell recognition of tumor cells, suggesting these modalities work via complementary, but not identical mechanisms. Importantly, complete tumor eradication was achieved in vivo (in a Hu-SCID tumor model) using a combinational therapy consisting of agonist administration just prior to the adoptive transfer of human anti-EphA2 CD8+ T cells, where either single modality was minimally beneficial. Preliminary data from additional studies targeting the tumor cell-overexpressed RTKs, Her2/neu and EGFR, suggest that this core treatment paradigm may be generalizeable to many (if not all) RTKs.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
9 September 2009 |
| Date Type: |
Completion |
| Defense Date: |
3 August 2009 |
| Approval Date: |
9 September 2009 |
| Submission Date: |
4 September 2009 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Medicine > Immunology |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
antigen; cancer; EphA2; immunotherapy; presentation; receptor tyrosine kinase |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-09042009-154009/, etd-09042009-154009 |
| Date Deposited: |
10 Nov 2011 20:01 |
| Last Modified: |
19 Dec 2016 14:37 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/9327 |
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