Transient ablation of regulatory T cells improves antitumor immunity in colitis-associated colon cancer
Pastille E, Bardini K, Fleissner D, Adamczyk A, Frede A, Wadwa M, von Smolinski D, Kasper S, Sparwasser T, Gruber A, Schuler M, Sakaguchi S, Roers A, Müller W, Hansen W, Buer J, Westendorf A
Published in
Cancer research: Volume 74, Issue 16, Page 4258-69
Abstract
Regulatory T cells (Treg) are supportive to cancer development in most tissues, but their role in colitis-associated colon cancer (CAC) remains unclear. In this study, we investigated the role of CD4(+)Foxp3(+) Treg in a mouse model of CAC and in patients with colon cancer. These Treg were increased strongly in number in a mouse model of CAC and in the peripheral blood of patients with colon cancer, exhibiting an activated phenotype as defined by elevated expression of GARP, CD103, CTLA-4, and IL10, along with an increased suppressive effect on the proliferation and Th1 cytokine expression of CD4(+)CD25(-) responder T cells ex vivo. Transient ablation of CD4(+)Foxp3(+) Treg during tumor development in the CAC model suppressed tumor outgrowth and distribution, accompanied by an increased number of CD8(+)IFNγ/granzyme B-producing effector T cells. Conversely, inactivation of IL10 in Treg did not elevate the antitumor response but instead further boosted tumor development. Our results establish a tumor-promoting function for Treg during CAC formation, but they also suggest that a selective, transient ablation of Treg can evoke antitumor responses, with implications for immunotherapeutic interventions in patients with CAC.
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