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Kawabe, Mayumi (2009) DEVELOPING COMBINATIONAL IMMUNOTHERAPIES TARGETING TUMOR RECEPTOR TYROSINE KINASES. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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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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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Kawabe, Mayumimak94@pitt.eduMAK94
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairStorkus, Walter Jstorkuswj@upmc.eduSTORKUSW
Committee MemberBrodsky, Jeffrey Ljbrodsky@pitt.eduJBRODSKY
Committee MemberEgorin, Merrill Jmje4@pitt.eduMJE4
Committee Member Robbins, Paul Dprobb@pitt.eduPROBB
Committee MemberBinder, Robert Jrjb42@pitt.eduRJB42
Committee MemberSalter, Russellrds@pitt.eduRDS
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:, etd-09042009-154009
Date Deposited: 10 Nov 2011 20:01
Last Modified: 19 Dec 2016 14:37


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