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Bladder cancer is one of the most common malignancies and has poor prognosis for patients with locally advanced, muscle-invasive, disease despite the efficacy of immune checkpoint blockade. To develop more effective immunotherapy strategies, we studied a genetic mouse model carrying deletion of Tp53 and Pten in the bladder, which recapitulates bladder cancer tumorigenesis and gene expression patterns found in patients. We discovered that tumor cells became more malignant and the tumor immune microenvironment evolved from an inflammatory to an immunosuppressive state. Accordingly, treatment with anti-PD1 was ineffective, but resistance to anti-PD1 therapy was overcome by combination with a CD40 agonist (anti-CD40), leading to strong antitumor immune responses. Mechanistically, this combination led to CD8+ T-cell recruitment from draining lymph nodes. CD8+ T cells induced an IFNγ-dependent repolarization toward M1-like/IFNβ-producing macrophages. CD8+ T cells, macrophages, IFN I, and IFN II were all necessary for tumor control, as demonstrated in vivo by the administration of blocking antibodies. Our results identify essential cross-talk between innate and adaptive immunity to control tumor development in a model representative of anti-PD1–resistant human bladder cancer and provide scientific rationale to target CD40 in combination with blocking antibodies, such as anti-PD1/PD-L1, for muscle-invasive bladder cancer.

Innate lymphoid cells (ILC) are a family of immune cells that are emerging as potent orchestrators of immune responses. In cancer, ILCs display both pro- and antitumorigenic functions depending on the nature of the tumor and the involved ILC subset. Little is known about the ILC–tumor cross-talk in human melanoma. Here, we showed that ILC1s were enriched but functionally impaired in cytokine secretion in both peripheral blood mononuclear cells and tumor-infiltrated lymph nodes of melanoma patients. These findings were confirmed in vivo in murine cutaneous melanoma. Multiple immunosuppressive mechanisms are described in the melanoma microenvironment. Among others, adenosine and kynurenines were shown to suppress antitumor immune responses. By exposing ILCs to adenosine and kynurenines, we observed a similar shift toward the ILC1 subset distribution and impairment in proinflammatory cytokine production to that of patient samples studied ex vivo. Thus, we hypothesized that the immunosuppressive microenvironment of malignant melanoma might shape ILC subpopulations. Hence, we provide a rationale for the use of drugs targeting adenosine and kynurenine pathways in melanoma patients.

microRNAs are short noncoding RNAs that regulate protein expression posttranscriptionally. We previously showed that miR-155 promotes effector CD8+ T-cell responses. However, little is known about the regulation of miR-155 expression. Here, we report that antigen affinity and dose determine miR-155 expression in CD8+ T cells. In B16 tumors expressing a low-affinity antigen ligand, tumor-specific infiltrating CD8+ T cells showed variable miR-155 expression, whereby high miR-155 expression was associated with more cytokine-producing cells and tumor control. Moreover, anti–PD-1 treatment led to both increased miR-155 expression and tumor control by specific CD8+ T cells. In addition, miR-155 overexpression enhanced exhausted CD8+ T-cell persistence in the LCMV cl13 chronic viral infection model. In agreement with these observations in mouse models, miR-155 expression in human effector memory CD8+ T cells positively correlated with their frequencies in tumor-infiltrated lymph nodes of melanoma patients. Low miR-155 target gene signature in tumors was associated with prolonged overall survival in melanoma patients. Altogether, these results raise the possibility that high miR-155 expression in CD8+ tumor-infiltrating T cells may be a surrogate marker of the relative potency of in situ antigen-specific CD8+ T-cell responses.

Immunotherapy revolutionized the treatment of cancer patients. However, the lack of tumor specific T-cells and the immunosuppressive tumor microenvironment remain the major obstacles in curing treatment-resistant tumors. Here, we show that a novel, propagating noncytopathic virotherapy expressing the tumor-associated antigen TRP2 can eradicate established tumors. Interestingly, this was dependent on the route of treatment. Systemic administration of gene-based virotherapy induced a high number of tumor-infiltrating TRP2 specific CD8+ T-cells but was not able to cure established tumors. Moreover, localized tumor therapy in the periphery cured also distant metastasis in the lung, indicating that the locally induced immune response generates a systemic antitumor effect. Localized virotherapy predominantly infects tumor cells and tumor-associated fibroblasts, resulting in a proinflammatory reprogramming of the tumor microenvironment. Our data reveal that this immune activation is dependent on type I IFN signaling on the host but not on the tumor cell. These results have important clinical implications: i) our data explain why T-cell transfer or T-cell vaccines alone do not cure established tumors; ii) intratumoral gene-based cancer vaccination is superior to systemic treatment; and iii) a successful local antitumor response is associated with an efficient systemic antitumor response. Directly cancer targeting noncytopathic gene-based vaccines may be a promising approach by simultaneously supercharging the suppressive tumor microenvironment and inducing an adaptive immune response against selected tumor antigens. Citation Format: Lukas Flatz, Sandra Ring, David Bomze, Lucas Onder, Jovana Cupovic, Sarah Schmidt, Klaus Orlinger, Andrej Besse, Lenka Besse, Christoph Driessen, Hung-Wei Cheng, Alexander Lercher, Daniel Speiser, Tobias Bald, Andreas Bergthaler, Burkhard Ludewig. Virotherapy eradicates established melanoma by reprogramming the tumor microenvironment and engaging the adaptive immunity [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A070.

T cell-based immunotherapies have brought great progress for cancer patients, but many questions still remain open with regard to mechanisms of action and immune regulation in the tumor microenvironment. Methods: We setup a well-controlled co-culture system to study the dynamic T cell - cancer cell interplay. Low passage MelanA-expressing melanoma cell lines were cultured with MelanA-specific CD8+ T cells and characterized using differential gene expression analysis and flow cytometry. Results: As expected, significant fractions of melanoma cells died in presence of melanoma-specific CD8+ T cells. However, still some melanoma cells persisted during up to three days of co-culture. Characterization of the surviving melanoma cells revealed increased mRNA levels of genes associated with antigen processing and presentation: HLA Class I-encoding genes (HLA-A and HLA-B), HLA Class 2-encoding genes (HLA-DRA and HLA-DRB) and CD74, the invariant chain that stabilizes the complex of HLA Class II α and β chains until it is loaded with a peptide, were strongly increased after co-culture, as well as TAP1 and TAP2 (encoding transporter associated with antigen presentation), responsible for peptide transfer from the cytosol to the endoplasmic reticulum (Neefjes et al., 2011). HLA-Class I and HLA-DR expression was also strongly increased at the protein level as assessed at 48h of co-culture. These gene and protein expression changes were dependent on antigen-specific interaction of CTLs with melanoma cells and were mediated by IFNγ and TNFα, two cytokines secreted by CTLs upon antigen recognition. Discussion: So far, mainly immunosuppressive mechanisms of cancer cells upon exposure to CTLs were described, such as increased expression of IDO1 and the inhibitory receptor ligand PDL1 (Spranger et al., 2013). Here we show that further to these immunosuppressive mechanisms, melanoma cells respond to melanoma-specific CTLs with an IFNγ-driven upregulation of genes involved in antigen presentation. Increased antigen-presentation likely increases target cell recognition of CTLs. These findings may play a role in successful immunotherapy, and might explain why IFNγ blockade in situations of anti-tumor immune attack not only blocks the immunosuppressive response of melanoma cells but also the anti-tumor T cell response (McGray et al., 2013). References: McGray, A.J.R., Hallett, R., Bernard, D., Swift, S.L., Zhu, Z., Teoderascu, F., VanSeggelen, H., Hassell, J.A., Hurwitz, A.A., Wan, Y., et al. (2013). Immunotherapy-induced CD8+ T Cells Instigate Immune Suppression in the Tumor. Mol Ther 22, 206-218. Neefjes, J., Jongsma, M.L.M., Paul, P., and Bakke, O. (2011). Towards a systems understanding of MHC class I and MHC class II antigen presentation. Nat Rev Immunol 11, 823-836. Spranger, S., Spaapen, R.M., Zha, Y., Williams, J., Meng, Y., Ha, T.T., and Gajewski, T.F. (2013). Up-Regulation of PD-L1, IDO, and Tregs in the Melanoma Tumor Microenvironment Is Driven by CD8+ T Cells. Sci Transl Med 5, 200ra116-200ra116. Citation Format: Natalie J. Neubert, Laure Tillé, David Barras, Charlotte Soneson, Petra Baumgaertner, Donata Rimoldi, Mauro Delorenzi, Silvia A. Fuertes Marraco, Daniel E. Speiser. Melanoma cells respond to CD8+ T cell attack by upregulation of genes associated with antigen processing and presentation. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B34.

Autoimmune side effects are frequent in patients with cancer treated with immune checkpoint–targeting antibodies, but are rare with cancer vaccines. Here, we present a case report on a patient with metastatic melanoma who developed pulmonary sarcoid–like granulomatosis following repetitive vaccinations with peptides and CpG. Despite multiple metastases, including one lesion in the brain, the patient is alive and well more than 13 years after the diagnosis of metastatic disease. The strongly activated tumor-specific CD8+ T cells showed robust long-term memory and effector functions. It is possible that long-term survival and adverse autoimmune events may become more common for vaccines inducing robust anticancer immune responses as were present in this patient. Cancer Immunol Res; 2(12); 1148–53. ©2014 AACR.

Antibody–drug conjugates (ADC) are emerging as powerful treatment strategies with outstanding target-specificity and high therapeutic activity in patients with cancer. Brentuximab vedotin represents a first-in-class ADC directed against CD30+ malignancies. We hypothesized that its sustained clinical responses could be related to the stimulation of an anticancer immune response. In this study, we demonstrate that the dolastatin family of microtubule inhibitors, from which the cytotoxic component of brentuximab vedotin is derived, comprises potent inducers of phenotypic and functional dendritic cell (DC) maturation. In addition to the direct cytotoxic effect on tumor cells, dolastatins efficiently promoted antigen uptake and migration of tumor-resident DCs to the tumor-draining lymph nodes. Exposure of murine and human DCs to dolastatins significantly increased their capacity to prime T cells. Underlining the requirement of an intact host immune system for the full therapeutic benefit of dolastatins, the antitumor effect was far less pronounced in immunocompromised mice. We observed substantial therapeutic synergies when combining dolastatins with tumor antigen–specific vaccination or blockade of the PD-1–PD-L1 and CTLA-4 coinhibitory pathways. Ultimately, treatment with ADCs using dolastatins induces DC homing and activates cellular antitumor immune responses in patients. Our data reveal a novel mechanism of action for dolastatins and provide a strong rationale for clinical treatment regimens combining dolastatin-based therapies, such as brentuximab vedotin, with immune-based therapies. Cancer Immunol Res; 2(8); 741–55. ©2014 AACR.

In the last decades, incidence of melanoma has steadily increased worldwide. Once melanoma has metastasized, this advanced stage of disease is extremely difficult to treat and does not respond to current therapies [1]. Numerous recent studies have emphasized the role of immune cells in the tumor progression [2, 3]. Moreover, some particular treatments such as immunotherapies enable to act on these immune cells to block tumor progression. A precise identification of the different immune actors in tissue sections is a preliminary step in the choice of these immunotherapies. Histological analysis of biological tissues achieved by pathologists allows a visualization of the immune cell types in the microenvironment. Yet, this step of vital importance is time-consuming, expensive and operator-dependent. The aim of the study is to characterize the immunologic microenvironment of tumor cells in metastatic lymph nodes by FTIR imaging and to develop a tool of decision for the use of immunotherapies. FTIR imaging is an emerging technique in the domain of histopathology that provides spatially resolved information on the chemical composition of the tissue based on the vibrational signature of tissue components (protein, DNA, RNA, lipids…). Because of its potential to probe chemical constituents without dye or specific reagent, FTIR imaging could become a powerful tool in diagnostics to complement the existing methods. 34 biopsies from 13 patients enrolled in a vaccination study against metastatic melanoma were collected. These biopsies of metastatic lymph nodes were surgically removed before or after the vaccination. For each biopsie, several immunostainings were done to target immune infiltration (B cells, cytotoxic T cells, auxiliary T cells and T regulatory). A collection of infrared spectra from each cell types present in the tissue was accumulated (melanoma cells, lymphocytes B, T auxiliary, T cytotoxic, erythrocytes, fibroblasts, endothelial cells and the extracellular matrix). On basis of this spectral database and with supervised analysis (Partial Least Square Discriminant Analysis), we were able to obtain a predictive model for histological characterization of cancerous tissues on the basis of the IR images only. Finally, we validated this predictive model for histological component recognition on other patient tissues. References[1] Gray-Schoper V.,Wellbrock C., Marais R., Nature 2007, 445, pp. 851-857. [2] Hanahan D. and Weinberg R. A., Cell 2011,144, pp.646-674. [3] Erdag G, Schaefer J T, Smolkin M E, Deacon D H, Shea S M, Dengel L T, Patterson J W, Slingluff C L, Cancer Research 2012, 72, pp.1070-1080. Citation Format: Noémie Wald, Daniel E. Speiser, Pu Yan, Erik Goormaghtigh. Characterization of melanoma metastases and the immune microenvironment by infrared imaging. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr B89.