Despite the sustained efforts of numerous groups to develop immune approaches for the treatment of cancer, thus far, the therapeutic responses have been disappointing. The reasons for this failure remain unknown. Thus, in the current study we propose to study the role of T-cell maturation stage in determining T-cell susceptibility to tumor-induced suppression by alterations in TGF-b susceptibility. Memory and effector CD8+ T cells are functionally more responsive than naive cells. Thus, we hypothesized that memory and effector T cells were less susceptible to tumor-induced suppression than naive cells. Paradoxically, we found that effector CD8+ T cells were considerably more susceptible to tumor-induced suppression than naive cells (90% vs. 30%). Our data suggest that adoptive transfer of in vitro activated effector CD8+ T cells may be ineffective due to increased CD8+ T-cell susceptibility to tumor-induced suppression. Regarding the mechanisms responsible for this disparate effect, we found that TGF-b was a key molecular mediator of suppression, and expression of transcriptional regulators of TGF-b signaling (Smad4 and TGF-bRII) correlated with T-cell status and susceptibility to suppression. Based on these observations, we propose the following hypothesis: CD8+ T-cell maturation status (naive, effector and memory) determines susceptibility to tumor-induced suppression, with effector and memory T cells being more susceptible to suppression than naive T cells, due to increased responsiveness to TGF-b. In order to evaluate antigen specific CD8+ T-cell responses, we will use CD8+ T cells from transgenic mice expressing a CD8+ TCR against gp100/pmel (a self antigen naturally expressed by normal melanocytes and melanoma cells) and a non-self antigen, chicken ovalbumin (OT-I). 1) We will examine the susceptibility of naive, effector and memory CD8+ T cells to TGF-b in vitro, and whether expression of TGF-bRII and Smads correlates with susceptibility to suppression. 2) We will evaluate the in vivo suppressive effect of tumor disseminated disease (early and established) on naive, effector and memory CD8+ T cells, and the effect of depleting suppressor cells or blocking TGF-b on naive, effector and memory CD8+ T-cell responses. 3) We will study whether interfering with TGF-b signaling in vivo in CD8+ T cells evenly rescues naive, effector and memory TCR transgenic CD8+ T cells from tumor-induced suppression. ? ? Narrative ? The results of T-cell based immune therapeutic approaches against cancer based on adoptive cell transfer and vaccination, thus far, have been disappointing for reasons that remain unknown. Thus, in the current study we propose to study the role of T-cell maturation stage (naive, effector and memory) in determining T-cell susceptibility to tumor-induced suppression by alterations in TGF-b susceptibility. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21CA127037-01A1
Application #
7386277
Study Section
Cancer Immunopathology and Immunotherapy Study Section (CII)
Program Officer
Mccarthy, Susan A
Project Start
2008-01-01
Project End
2009-12-31
Budget Start
2008-01-01
Budget End
2008-12-31
Support Year
1
Fiscal Year
2008
Total Cost
$207,225
Indirect Cost
Name
University of Chicago
Department
Surgery
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Zloza, Andrew; Kohlhapp, Frederick J; Lyons, Gretchen E et al. (2012) NKG2D signaling on CD8ýýý T cells represses T-bet and rescues CD4-unhelped CD8ýýý T cell memory recall but not effector responses. Nat Med 18:422-8
Kohlhapp, Frederick J; Zloza, Andrew; O'Sullivan, Jeremy A et al. (2012) CD8(+) T cells sabotage their own memory potential through IFN-?-dependent modification of the IL-12/IL-15 receptor ? axis on dendritic cells. J Immunol 188:3639-47
Bellavance, Emily C; Kohlhapp, Frederick J; Zloza, Andrew et al. (2011) Development of tumor-infiltrating CD8+ T cell memory precursor effector cells and antimelanoma memory responses are the result of vaccination and TGF-ýý blockade during the perioperative period of tumor resection. J Immunol 186:3309-16
Zloza, Andrew; Jagoda, Michael C; Lyons, Gretchen E et al. (2011) CD8 co-receptor promotes susceptibility of CD8+ T cells to transforming growth factor-? (TGF-?)-mediated suppression. Cancer Immunol Immunother 60:291-7
O'Sullivan, Jeremy A; Zloza, Andrew; Kohlhapp, Frederick J et al. (2011) Priming with very low-affinity peptide ligands gives rise to CD8(+) T-cell effectors with enhanced function but with greater susceptibility to transforming growth factor (TGF)?-mediated suppression. Cancer Immunol Immunother 60:1543-51
Cote, Anik L; Zhang, Peisheng; O'Sullivan, Jeremy A et al. (2011) Stimulation of the glucocorticoid-induced TNF receptor family-related receptor on CD8 T cells induces protective and high-avidity T cell responses to tumor-specific antigens. J Immunol 186:275-83