In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 77, No. 13_Supplement ( 2017-07-01), p. 1608-1608
Abstract:
The IL-2 receptor (IL-2R) is an attractive target for cancer immunotherapy as it controls both immune-suppressive regulatory T cells (Tregs) and anti-tumor T cells. We tested depleting Tregs as immunotherapy using anti-CD25 (high-affinity IL-2R subunit) antibodies (αCD25) in ID8agg mouse ovarian cancer (OC). αCD25 reduced ascites and Treg numbers but failed to reduce tumor burden, possibly because it depleted newly activated anti-tumor T cells in tumor-draining lymph nodes. Thus, αCD25 could be novel malignant ascites palliation, but has limited stand-alone efficacy. We then tested IL-2/anti-IL-2 complexes (IL-2c) that selectively stimulate medium-affinity (CD122/CD132) IL-2R thought to expand anti-tumor T cells preferentially, but with little Treg effects. In contrast to several single agents we tested that failed to treat ID8agg (e.g., αCD25, αPD-L1, IL-2 fusion toxin denileukin diftitox), IL-2c alone durably reduced ID8agg tumor burden despite lowering the tumor microenvironmental CD8+/Treg ratio. Thus, we hypothesized that IL-2c improved CD8+ function, reduced Treg function, or both. IL-2c increased polyfunctional IFN-γ+TNF-α+ anti-tumor T cells as expected, an effect that persists weeks after drug clearance. IL-2c also increased anti-tumor T cell CD25 expression that increased IL-2 sensitivity and STAT5 phosphorylation, a likely mechanism for increased polyfunctionality. Unexpectedly, IL-2c reduced the Treg functional mediators CD25, TIGIT and granzyme B, and reduced Treg suppressive function. Thus, favorable Treg modifications are a novel IL-2c mechanism of action. Adding αCD25 to IL-2c to deplete Tregs further unexpectedly worsened IL-2c efficacy in ID8agg and reduced effector memory T cells and polyfunctional T cells in the tumor microenvironment, suggesting a previously unappreciated role for CD25 in IL-2c therapy. Similar data were seen in B16 melanoma, suggesting αCD25 reduction of IL-2c efficacy is not tumor or compartment-specific (ID8agg is peritoneal and B16 is subcutaneous). αPD-L1, an ineffective monotherapy in ID8agg, combined with IL-2c to promote complete responses, suggesting potential for potent, novel combinatorial approaches. Our data suggest that antagonizing high affinity IL-2R (such as to deplete Tregs with αCD25) has limited cancer immunotherapy utility without more specific Treg targeting. In contrast, stimulating medium-affinity IL-2R with CD122-selective IL-2c has great translational promise by simultaneously improving beneficial anti-tumor T cells and reducing detrimental Treg function. Citation Format: Justin M. Drerup, Sri Lakshmi Pandeswara, Aijie Liu, Curtis A. Clark, Alvaro S. Padron, Wanjiao Chen, Vincent Hurez, Tyler J. Curiel. CD122-selective IL-2/anti-IL-2 complexes reduce regulatory T cell function and promote CD8+ T cell polyfunctionality for durable ovarian cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1608. doi:10.1158/1538-7445.AM2017-1608
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2017-1608
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2017
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
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