Ex-Th17 Foxp3+ T cells - a novel subset of Foxp3+ T cells induced in cancer

Th17 and regulatory T (Treg) cells are integral in maintaining immune homeostasis and Th17-Treg misbalance associates with inflammation.\ud \ud We demonstrate that in addition to natural (n)Treg and induced (i)Treg cells developed from naïve precursors, Th17 cells are a novel source of Foxp3+ cells by converting into ex-Th17 Foxp3+ cells, and this helps to reconcile the contradictory information about the relevance in particularly of Th17 subset in immune surveillance.\ud \ud We identified IL-17A+Foxp3+ double-positive and ex-IL-17-producing IL-17A-Foxp3+ T cells to be the underlying mechanism of immune regulation in mesenchymal stem cell-mediated prolonged allograft survival. Further, we identified accumulation of IL17A+Foxp3+ and ex-Th17 Foxp3+ cells in tumor bearing mice, indicating progressive direct Th17-into-Treg cell conversion as a novel phenomenon in cancer.\ud \ud Moreover, we determined the importance of the Th17 cell plasticity for tumor induction and/or progression in ROR-g-/- mice. Our data indicate that RORgt is required not only for Th17 development, but also for effective Treg cell induction. TGF-b1 induced Foxp3 expression was reduced in ROR-g -/- cells. Further, tumor bearing ROR-g-/- mice showed significantly less Foxp3+ Treg cells, but higher IFNg+ Tcells compared to wild type animals.\ud \ud Increased infiltration of IL17+ and FoxP3+ CD4+ T cells in the human ovarian cancer ascites, with the presence of a distinct IL17+FoxP3+ subset, and a significant correlation between tumor-associated Th17 and Treg cells demonstrates the existence of Th17-Foxp3+ T cell inter-relationship in cancer patients.\ud \ud Yin-yang of IL17+ and Foxp3+ is important principle for improved clinical approaches targeting responses against self, allo and/or neo-self

The Landscape of Immune Microenvironments in Racially Diverse Breast Cancer Patients

Background: Immunotherapy is a rapidly evolving treatment option in breast cancer; However, the breast cancer immune microenvironment is understudied in Black and younger (<50 years) patients. Methods: We used histologic and RNA-based immunoprofiling methods to characterize the breast cancer immune landscape in 1,952 tumors from the Carolina Breast Cancer Study (CBCS), a population-based study that oversampled Black (n ¼ 1,030) and young women (n ¼ 1,039). We evaluated immune response leveraging markers for 10 immune cell populations, compared profiles to those in The Cancer Genome Atlas (TCGA) Project [n ¼ 1,095 tumors, Black (n ¼ 183), and young women (n ¼ 295)], and evaluated in association with clinical and demographic variables, including recurrence. Results: Consensus clustering identified three immune clusters in CBCS (adaptive-enriched, innate-enriched, or immune-quiet) that varied in frequency by race, age, tumor grade and subtype; however, only two clusters were identified in TCGA, which were predominantly comprised of adaptive-enriched and innate-enriched tumors. In CBCS, the strongest adaptive immune response was observed for basal-like, HER2-positive (HER2þ), triple-negative breast cancer (TNBC), and high-grade tumors. Younger patients had higher proportions of adaptive-enriched tumors, particularly among estrogen receptor (ER)-negative (ER-) cases. Black patients had higher frequencies of both adaptive-enriched and innate-enriched tumors. Immune clusters were associated with recurrence among ER- tumors, with adaptive-enriched showing the best and innate-enriched showing the poorest 5-year recurrence-free survival. Conclusions: These data suggest that immune microenvironments are intricately related to race, age, tumor subtype, and grade. Impact: Given higher mortality among Black and young women, more defined immune classification using cell-type–specific panels could help explain higher recurrence and ultimately lead to target-able interventions

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival