Germinal center-dependent and -independent immune responses of tumor-infiltrating B cells in human cancers

B cells play essential roles in immunity, mainly through the production of high affinity plasma cells (PCs) and memory B (Bmem) cells. The affinity maturation and differentiation of B cells rely on the integration of B-cell receptor (BCR) intrinsic and extrinsic signals provided by antigen binding and the microenvironment, respectively. In recent years, tumor infiltrating B (TIL-B) cells and PCs (TIL-PCs) have been revealed as important players in antitumor responses in human cancers, but their interplay and dynamics remain largely unknown. In lymphoid organs, B-cell responses involve both germinal center (GC)-dependent and GC-independent pathways for Bmem cell and PC production. Affinity maturation of BCR repertoires occurs in GC reactions with specific spatiotemporal dynamics of signal integration by B cells. In general, the reactivation of high-affinity Bmem cells by antigens triggers GC-independent production of large numbers of PC without BCR rediversification. Understanding B-cell dynamics in immune responses requires the integration of multiple tools and readouts such as single-cell phenotyping and RNA-seq, in situ analyses, BCR repertoire analysis, BCR specificity and affinity assays, and functional tests. Here, we review how those tools have recently been applied to study TIL-B cells and TIL-PC in different types of solid tumors. We assessed the published evidence for different models of TIL-B-cell dynamics involving GC-dependent or GC-independent local responses and the resulting production of antigen-specific PCs. Altogether, we highlight the need for more integrative B-cell immunology studies to rationally investigate TIL-B cells as a leverage for antitumor therapies.

Autologous T cell responses to primary human colorectal cancer spheroids are enhanced by ectonucleotidase inhibition

OBJECTIVE

T cells are major effectors of the antitumoural immune response. Their activation by tumour-associated antigens can unleash their proliferation and cytotoxic functions, leading to tumour cell elimination. However, tumour-related immunosuppressive mechanisms including the overexpression of immune checkpoints like programmed cell death protein-1 (PD-1), are also engaged, promoting immune escape. Current immunotherapies targeting these pathways have demonstrated weak efficacy in colorectal cancer (CRC). It is thus crucial to find new targets for immunotherapy in this cancer type.

DESIGN

In a prospective cohort of patients with CRC, we investigated the phenotype of tumour-related and non-tumour related intestinal T cells (n=44), particularly the adenosinergic pathway, correlating with clinical phenotype. An autologous coculture model was developed between patient-derived primary tumour spheroids and their autologous tumour-associated lymphocytes. We used this relevant model to assess the effects of CD39 blockade on the antitumour T cell response.

RESULTS

We show the increased expression of CD39, and its co-expression with PD-1, on tumour infiltrating T cells compared with mucosal lymphocytes. CD39 expression was higher in the right colon and early-stage tumours, thus defining a subset of patients potentially responsive to CD39 blockade. Finally, we demonstrate in autologous conditions that CD39 blockade triggers T cell infiltration and tumour spheroid destruction in cocultures.

CONCLUSION

In CRC, CD39 is strongly expressed on tumour infiltrating lymphocytes and its inhibition represents a promising therapeutic strategy for treating patients.

Antitumor immunity induced by antibody-based natural killer cell engager therapeutics armed with not-alpha IL-2 variant

Harnessing innate immunity is emerging as a promising therapeutic approach in cancer. We report here the design of tetraspecific molecules engaging natural killer (NK) cell-activating receptors NKp46 and CD16a, the β-chain of the interleukin-2 receptor (IL-2R), and a tumor-associated antigen (TAA). In vitro, these tetraspecific antibody-based natural killer cell engager therapeutics (ANKETs) induce a preferential activation and proliferation of NK cells, and the binding to the targeted TAA triggers NK cell cytotoxicity and cytokine and chemokine production. In vivo, tetraspecific ANKETs induce NK cell proliferation and their accumulation at the tumor bed, as well as the control of local and disseminated tumors. Treatment of non-human primates with CD20-directed tetraspecific ANKET leads to CD20⁺ circulating B cell depletion, with minimal systemic cytokine release and no sign of toxicity. Tetraspecific ANKETs, thus, constitute a technological platform for harnessing NK cells as next-generation cancer immunotherapies.

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Tetraspecific ANKETs constitute a technological platform to harness NK cells in cancer

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Tetraspecific ANKETs target NKp46, CD16a, IL-2Rβ, and a tumor antigen

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Tetraspecific ANKETs stimulate NK cell proliferation, activation, and antitumor functions

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In vivo, tetraspecific ANKETs promote NK cell tumor accumulation and antitumor activity

Neutralizing Anti-Granulocyte Macrophage-Colony Stimulating Factor Autoantibodies Recognize Post-Translational Glycosylations on Granulocyte Macrophage-Colony Stimulating Factor Years Before Diagnosis and Predict Complicated Crohn's Disease

BACKGROUND & AIMS

Anti-granulocyte macrophage-colony stimulating factor autoantibodies (aGMAbs) are detected in patients with ileal Crohn's disease (CD). Their induction and mode of action during or before disease are not well understood. We aimed to investigate the underlying mechanisms associated with aGMAb induction, from functional orientation to recognized epitopes, for their impact on intestinal immune homeostasis and use as a predictive biomarker for complicated CD.

METHODS

We characterized using enzyme-linked immunosorbent assay naturally occurring aGMAbs in longitudinal serum samples from patients archived before the diagnosis of CD (n = 220) as well as from 400 healthy individuals (matched controls) as part of the US Defense Medical Surveillance System. We used biochemical, cellular, and transcriptional analysis to uncover a mechanism that governs the impaired immune balance in CD mucosa after diagnosis.

RESULTS

Neutralizing aGMAbs were found to be specific for post-translational glycosylation on granulocyte macrophage-colony stimulating factor (GM-CSF), detectable years before diagnosis, and associated with complicated CD at presentation. Glycosylation of GM-CSF was altered in patients with CD, and aGMAb affected myeloid homeostasis and promoted group 1 innate lymphoid cells. Perturbations in immune homeostasis preceded the diagnosis in the serum of patients with CD presenting with aGMAb and were detectable in the noninflamed CD mucosa.

CONCLUSIONS

Anti-GMAbs predict the diagnosis of complicated CD long before the diagnosis of disease, recognize uniquely glycosylated epitopes, and impair myeloid cell and innate lymphoid cell balance associated with altered intestinal immune homeostasis.

Targeting MICA/B with cytotoxic therapeutic antibodies leads to tumor control

Background: MICA and MICB are tightly regulated stress-induced proteins that trigger the immune system by binding to the activating receptor NKG2D on cytotoxic lymphocytes. MICA and MICB are highly polymorphic molecules with prevalent expression on several types of solid tumors and limited expression in normal/healthy tissues, making them attractive targets for therapeutic intervention. Methods: We have generated a series of anti-MICA and MICB cross-reactive antibodies with the unique feature of binding to the most prevalent isoforms of both these molecules. Results: The anti-MICA and MICB antibody MICAB1, a human IgG1 Fc-engineered monoclonal antibody (mAb), displayed potent antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) of MICA/B-expressing tumor cells in vitro. However, it showed insufficient efficiency against solid tumors in vivo, which prompted the development of antibody-drug conjugates (ADC). Indeed, optimal tumor control was achieved with MICAB1-ADC format in several solid tumor models, including patient-derived xenografts (PDX) and carcinogen-induced tumors in immunocompetent MICAgen transgenic mice. Conclusions: These data indicate that MICA and MICB are promising targets for cytotoxic immunotherapy.

Targeting MICA/B with cytotoxic therapeutic antibodies leads to tumor control

Background: MICA and MICB are tightly regulated stress-induced proteins that trigger the immune system by binding to the activating receptor NKG2D on cytotoxic lymphocytes. MICA and MICB are highly polymorphic molecules with prevalent expression on several types of solid tumors and limited expression in normal/healthy tissues, making them attractive targets for therapeutic intervention. Methods: We have generated a series of anti-MICA and MICB cross-reactive antibodies with the unique feature of binding to the most prevalent isoforms of both these molecules. Results: The anti-MICA and MICB antibody MICAB1, a human IgG1 Fc-engineered monoclonal antibody (mAb), displayed potent antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) of MICA/B-expressing tumor cells in vitro. However, it showed insufficient efficiency against solid tumors in vivo, which prompted the development of antibody-drug conjugates (ADC). Indeed, optimal tumor control was achieved with MICAB1-ADC format in several solid tumor models, including patient-derived xenografts (PDX) and carcinogen-induced tumors in immunocompetent MICAgen transgenic mice. Conclusions: These data indicate that MICA and MICB are promising targets for cytotoxic immunotherapy.

A5 GM-CSF AUTOANTIBODIES: PREDICTORS OF CROHN’S DISEASE DEVELOPMENT AND A NOVEL THERAPEUTIC APPROACH

Background

Crohn’s disease (CD) is a heterogenous, chronic inflammatory disorder driven by a combination of genetic, environmental, and microbiota-dependent risk factors. Mononuclear phagocytes (MNP) are crucial cells that maintain intestinal homeostasis. An important cytokine for MNP survival and function is granulocyte-macrophage colony stimulating factor (GM-CSF). Interestingly, several studies reported CD-associated genetic risk variants within the GM-CSF receptor and its downstream signaling components. Furthermore, high titers of autoantibodies specific to GM-CSF can be detected in CD patients. Taken together, this data suggests an important role for GM-CSF in abrogation of CD development in a subgroup of patients.

Aims

This study sought to investigate the function of GM-CSF autoantibodies in CD.

Methods

We retrospectively quantified and characterized GM-CSF autoantibodies in sera of 220 CD, 200 ulcerative colitis (UC) patients, and 220 healthy controls (HC) sampled at 3 time points prior to disease diagnosis and one time point after diagnosis. ELISA was used to determine GM-CSF autoantibody titers and isotypes followed by in vitro multiplexed mass cytometry (CyTOF) neutralization assays on peripheral blood mononuclear cells. Flow cytometry and CyTOF were used to map the profile of immune cells isolated from inflamed and non-inflamed CD mucosa.

Results

Our data demonstrates that GM-CSF autoantibodies are specific to CD, significantly elevated up to 7 years prior to diagnosis of disease, and correlate with disease location, severity, and complications at the time of diagnosis. Moreover, in contrast to GM-CSF autoantibodies in pulmonary alveolar proteinosis patients, CD-associated autoantibodies neutralize GM-CSF via specific recognition of post-translational modifications (PTM), affecting MNP function. Removal of PTM enabled GM-CSF to escape autoantibody binding and restored MNP response to GM-CSF in the presence of neutralizing antibodies, indicating a potential therapeutic avenue. Furthermore, we identified group 3 innate lymphoid cells (ILC3) as a major source of GM-CSF in the healthy intestinal tract, suggesting intriguing crosstalk of MNP and ILC3 across the GM-CSF-GM-CSFR axis.

Conclusions

Our results identify GM-CSF autoantibodies as predictive serological biomarker for CD in a subgroup of patients presenting with severe and complicated form of disease at the time of diagnosis. The presence of GM-CSF autoantibodies precedes the onset of CD by several years and likely abrogates homeostatic immune cell crosstalk involving ILC3 and MNP, suggesting the development of a pre-diseased state in CD patients.

Funding Agencies

CIHRDr. Edward Ketchum Graduate Scholarship

Association of COVID-19 inflammation with activation of the C5a-C5aR1 axis

Coronavirus disease 2019 (COVID-19) is a disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has resulted in a pandemic1. The C5a complement factor and its receptor C5aR1 (also known as CD88) have a key role in the initiation and maintenance of several inflammatory responses by recruiting and activating neutrophils and monocytes1. Here we provide a longitudinal analysis of immune responses, including phenotypic analyses of immune cells and assessments of the soluble factors that are present in the blood and bronchoalveolar lavage fluid of patients at various stages of COVID-19 severity, including those who were paucisymptomatic or had pneumonia or acute respiratory distress syndrome. The levels of soluble C5a were increased in proportion to the severity of COVID-19 and high expression levels of C5aR1 receptors were found in blood and pulmonary myeloid cells, which supports a role for the C5a-C5aR1 axis in the pathophysiology of acute respiratory distress syndrome. Anti-C5aR1 therapeutic monoclonal antibodies prevented the C5a-mediated recruitment and activation of human myeloid cells, and inhibited acute lung injury in human C5aR1 knock-in mice. These results suggest that blockade of the C5a-C5aR1 axis could be used to limit the infiltration of myeloid cells in damaged organs and prevent the excessive lung inflammation and endothelialitis that are associated with acute respiratory distress syndrome in patients with COVID-19.

CD3 and CD20 immune cell densities in primary tumors, lymph node metastasis, and recurrent disease samples of head and neck squamous cell carcinoma

6551

Background: Immune cell (IC) infiltrates in primary tumors (PT) have been identified as prognostic markers in head and neck squamous cell carcinoma (HNSCC). IC densities may differ among PT, lymph node metastasis (LNM) and recurrent disease (RD) and by primary disease site (oral cavity- OC, oropharynx- OP, hypopharynx- HP, larynx- L). Here, we compare CD3 and CD20 IC densities in PT, LNM and RD in paired samples from different disease sites and determine the prognostic impact of IC infiltrates. Methods: Tissue microarrays with 425 PT, 198 LNM and 46 RD samples--each in triplicate--were stained immunohistochemically for CD3 and CD20 in the same slide. Immune cell densities per mm2 were determined using a digital image analysis software (QuPath). Individual means were calculated from triplicates of each sample. IC infiltrates from different sample types (PT, LNM, RD) and primary tumor sites were compared using Kruskal-Wallis and Mann-Whitney-U tests. Paired samples were compared using Wilcoxon signed rank test. IC densities were classified as CD3 high/low and CD20 high/low for each primary tumor site using the individual median as a cut-off. Overall survival (OS) was calculated using the Kaplan-Meier method. P-values for each hypothesis were corrected using a false discovery rate of 5%. Results: CD3 and CD20 IC densities differed significantly by sample type (both p<0.0001) and primary site (CD3: p=0.012, CD20: p=0.0017). CD3 and CD20 densities were significantly lower in PT compared to LNM or in RD compared to PT and LNM. Paired samples (n=172) revealed a significantly higher CD3 and CD20 density (both p<0.0005) in LNM compared to PT, but no significant differences between PT and RD (n=28, p>0.05). CD3 densities were significantly higher than CD20 densities in all sample types. CD3high patients had the best prognosis in all sites except for OC (q<0.05) independent of CD20 status. In OC, CD3 density was not prognostic, but CD3low/CD20high patients had the worst OS compared to CD3low/CD20low and CD3high/CD20high or even CD3high/CD20low patients (p=0.018) who had the best prognosis. Conclusions: IC densities of CD3 and CD20 vary by sample type and primary site. Except for OC, in all sites the prognostic impact is determined by CD3high, whereas in OSCC only the combination of CD3 and CD20 IC densities achieves a good prognostic value. Interestingly, CD3low/CD20high patients have the worst overall survival in OC patients. Further work is needed to understand the interaction of B- and T cell infiltrates in the tumor, especially in OC.

Multiplexed Immunohistochemical Consecutive Staining on Single Slide (MICSSS): Multiplexed Chromogenic IHC Assay for High-Dimensional Tissue Analysis

Disease states and cellular compartments can display a remarkable amount of heterogeneity, and truly appreciating this heterogeneity requires the ability to detect and probe each subpopulation present. A myriad of recent single-cell assays has allowed for in-depth analysis of these diverse cellular populations; however, fully understanding the interplay between each cell type requires knowledge not only of their mere presence but also of their spatial organization and their relation one to the other. Immunohistochemistry allows for the visualization of cells and tissue; however, standard techniques only allow for the use of very few probes on a single specimen, not allowing for in-depth analysis of complex cellular heterogeneity. A number of multiplex imaging techniques, such as immunofluorescence and multiplex immunohistochemistry, have been proposed to allow probing more cellular markers at once; however, many of these techniques still have their limitations. The use of fluorescent markers has an inherent limitation to the number of probes that can be simultaneously used due to spectral overlap. Moreover, other proposed multiplex IHC methods are time-consuming and require expensive reagents. Still, many of the methods rely on frozen tissue, which deviates from standards in human pathological evaluation. Here, we describe a multiplex IHC technique, staining for consecutive markers on a single slide, which utilizes similar steps and similar reagents as standard IHC, thus making it possible for any lab with standard IHC capabilities to perform this useful procedure. This method has been validated and confirmed that consecutive markers can be stained without the risk of cross-reactivity between staining cycles. Furthermore, we have validated that this technique does not lead to decreased antigenicity of subsequent epitopes probed, nor does it lead to steric hindrance.

DNA alteration-based classification of uveal melanoma gives better prognostic stratification than immune infiltration, which has a neutral effect in high-risk group

Background

In uveal melanomas, immune infiltration is a marker of poor prognosis. This work intended to decipher the biological characteristics of intra‐tumor immune population, compare it to other established biomarkers and to patients' outcome.

Methods

Primary, untreated, and mainly large uveal melanomas with retinal detachment were analyzed using: transcriptomic profiling (n = 15), RT‐qPCR (n = 36), immunohistochemistry (n = 89), Multiplex Ligation‐dependent Probe Amplification (MLPA) for copy number alterations (CNA) analysis (n = 89), array‐CGH (n = 17), and survival statistics (n = 86).

Results

Gene expression analysis divided uveal melanomas into two groups, according to the IFNγ/STAT1‐IRF1 pathway activation. Tumors with IFNγ‐signature had poorer prognosis and showed increased infiltration of CD8⁺ T lymphocytes and macrophages. Cox multivariate analyses of immune cell infiltration with MLPA data delineated better prognostic value for three prognostic groups (three‐tier stratification) than two (two‐tier stratification). CNA‐based model comprising monosomy 3, 8q amplification, and LZTS1and NBL1 deletions emerged as the best predictor for disease‐free survival. It outperformed immune cell infiltration in receiver operating characteristic curves. The model that combined CNA and immune infiltration defined risk‐groups according to the number of DNA alterations. Immune cell infiltration was increased in the high‐risk group (73.7%), where it did not correlate with patient survival, while it was associated with poorer outcome in the intermediate risk‐group.

Conclusions

High degree of immune cell infiltration occurs in a subset of uveal melanomas, is interferon‐gamma‐related, and associated with poor survival. It allows for two‐tier stratification, which is prognostically less efficient than a three‐tier one. The best prognostic stratification is by CNA model with three risk‐groups where immune cell infiltration impacts only some subgroups.

Host tissue determinants of tumour immunity

Although common evolutionary principles drive the growth of cancer cells regardless of the tissue of origin, the microenvironment in which tumours arise substantially differs across various organ sites. Recent studies have established that, in addition to cell-intrinsic effects, tumour growth regulation also depends on local cues driven by tissue environmental factors. In this Review, we discuss how tissue-specific determinants might influence tumour development and argue that unravelling the tissue-specific contribution to tumour immunity should help the development of precise immunotherapeutic strategies for patients with cancer.

Cocultures of human colorectal tumor spheroids with immune cells reveal the therapeutic potential of MICA/B and NKG2A targeting for cancer treatment

Background

Immunotherapies still fail to benefit colorectal cancer (CRC) patients. Relevant functional assays aimed at studying these failures and the efficacy of cancer immunotherapy in human are scarce. 3D tumor cultures, called tumor organoids or spheroids, represent interesting models to study cancer treatments and could help to challenge these issues.

Methods

We analyzed heterotypic cocultures of human colon tumor-derived spheroids with immune cells to assess the infiltration, activation and function of T and NK cells toward human colorectal tumors in vitro.

Results

We showed that allogeneic T and NK cells rapidly infiltrated cell line-derived spheroids, inducing immune-mediated tumor cell apoptosis and spheroid destruction. NKG2D, a key activator of cytotoxic responses, was engaged on infiltrating cells. We thus assessed the therapeutic potential of an antibody targeting the specific ligands of NKG2D, MICA and MICB, in this system. Anti-MICA/B enhanced immune-dependent destruction of tumor spheroid by driving an increased NK cells infiltration and activation. Interestingly, tumor cells reacted to immune infiltration by upregulating HLA-E, ligand of the inhibitory receptor NKG2A expressed by CD8 and NK cells. NKG2A was increased after anti-MICA/B treatment and, accordingly, combination of anti-MICA/B and anti-NKG2A was synergistic. These observations were ultimately confirmed in a clinical relevant model of coculture between CRC patients-derived spheroids and autologous tumor-infiltrating lymphocytes.

Conclusions

Altogether, we show that tumor spheroids represent a relevant tool to study tumor-lymphocyte interactions on human tissues and revealed the antitumor potential of immunomodulatory antibodies targeting MICA/B and NKG2A.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0553-9) contains supplementary material, which is available to authorized users.

Abstract IA31: Measuring the emergence of non-self in tumors

Molecules generated by mutational and epigenetic processes in tumors have been associated with recognition of tumors by the innate and adaptive immune system. For example, neoantigens have been implicated in response to checkpoint blockade therapies. Likewise, the display of pathogen-associated patterns by nucleic acids unsilenced by epigenetic alterations have been implicated in activation of the innate immune system. Here we determine molecular features which place a tumor at a selective advantage or disadvantage, and how these selective pressures depend on the tumor’s environment. We have proposed general frameworks to address these questions. In the case of tumor neoantigens, we present a fitness model of candidate immunogenic neoantigens distributed across a tumor’s subclonal structure in a given microenvironment. We show how our approach can be used to characterize response to checkpoint-blockade therapies and apply it to the general problem of immune-driven tumor evolution in a unique cohort of long-term survivors of pancreatic cancer. In the case of immunostimulatory RNA, we proposed a method of calculating entropic forces for determining the likelihood of tumoral RNA being recognized as pathogen-associated and characterizing classes of pathogen mimicry.

Citation Format: Marta Luksza, Alexander Solovyov, Nicolas Vabret, Vinod Balachandran, Nadeem Riaz, Vladimir Makarov, Matthew D. Hellmann , Alexandra Snyder, Samuel Funt, Romain Remark, Miriam Merad, Sacha Gnjatic, Dean F. Bajorin, Jonathan Rosenberg, Steven Leach, Arnold J. Levine, Timothy A. Chan, Nina Bhardwaj, Jedd Wolchock, Benjamin D. Greenbaum. Measuring the emergence of non-self in tumors [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 IA31.

Anti-NKG2A mAb Is a Checkpoint Inhibitor that Promotes Anti-tumor Immunity by Unleashing Both T and NK Cells

Checkpoint inhibitors have revolutionized cancer treatment. However, only a minority of patients respond to these immunotherapies. Here, we report that blocking the inhibitory NKG2A receptor enhances tumor immunity by promoting both natural killer (NK) and CD8⁺ T cell effector functions in mice and humans. Monalizumab, a humanized anti-NKG2A antibody, enhanced NK cell activity against various tumor cells and rescued CD8⁺ T cell function in combination with PD-x axis blockade. Monalizumab also stimulated NK cell activity against antibody-coated target cells. Interim results of a phase II trial of monalizumab plus cetuximab in previously treated squamous cell carcinoma of the head and neck showed a 31% objective response rate. Most common adverse events were fatigue (17%), pyrexia (13%), and headache (10%). NKG2A targeting with monalizumab is thus a novel checkpoint inhibitory mechanism promoting anti-tumor immunity by enhancing the activity of both T and NK cells, which may complement first-generation immunotherapies against cancer.

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Blocking NKG2A unleashes both T and NK cell effector functions

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Combined blocking of the NKG2A and the PD-1 axis promotes anti-tumor immunity

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Blocking NKG2A and triggering CD16 illustrates the efficacy of dual checkpoint therapy

RAS status and neoadjuvant chemotherapy impact CD8+ cells and tumor HLA class I expression in liver metastatic colorectal cancer

Background

T lymphocytes and HLA expression on tumor cell both influence prognostic of localized colorectal cancer, but their role following chemotherapy in patients with liver metastatic colorectal cancer (mCRC) was not addressed.

Methods

One hundred fourteen patients treated in curative intend of liver mCRC were included in this retrospective study. Patients were either untreated or treated with neoadjuvant therapy containing an anti-EGFR, bevacizumab or oxaliplatin. Immune densities were quantified in the tumor core and in invasive margin of metastases, using Qupath software or a pathologist’s quantification. CD8, NKp46, Foxp3, CD163, HLA, PD-L1 were analyzed and were correlated with progression free survival (PFS) and overall survival (OS) using multivariable Cox proportional hazards models.

Results

In the whole cohort only a high CD8+ cells infiltrate, a high HLA-I expression and wild-type RAS/RAF status were associated with a better overall survival in both univariate and multivariate model. Moreover, CD8+ cells immune infiltrate at invasive margin combined to HLA expression in cancer cell could increase patient’s outcome prediction. RAS status but not immune cell infiltrate was associated with HLA expression on tumor cells. In comparison to untreated patients, neoadjuvant chemotherapy induced CD8+ cells recruitment and increased PD-L1 staining in immune infiltrates only for WT RAS patients. In this context, anti-EGFR and oxaliplatin based chemotherapy are the most powerful to induce CD8+ cells mobilization within the metastatic site.

Conclusions

While CD8 infiltrate and HLA expression appear to be prognostic for mCRC, CD8 and PD-L1 infiltrate are enhanced by neoadjuvant chemotherapy in mCRC under RAS status dependence.

Electronic supplementary material

The online version of this article (10.1186/s40425-018-0438-3) contains supplementary material, which is available to authorized users.

Abstract 2714: Combination of monalizumab and durvalumab as a potent immunotherapy treatment for solid human cancers

Inhibitory CD94-NKG2A (Natural Killer Group 2A) receptors are expressed on subsets of natural killer (NK) cells, γδ and CD8+ T cells. HLA-E (Human Leukocytes Antigen-E), the ligand for CD94-NKG2A, is upregulated on cancer cells of several solid tumors, providing a negative regulatory signal to tumor-infiltrating lymphocytes (TILs). Blockade of this immune checkpoint pathway with anti-NKG2A monoclonal antibodies (Ab) enhances NK cell responses to tumor cells in vitro and in humanized mice. Here, we describe NK and CD8+ T cell infiltrates in several human solid tumors by immunohistochemistry (IHC) and multicolor flow cytometry. We then studied the effects of in vitro targeting both pathways on primary human NK and CD8+ T cells. By using IHC on formalin-fixed paraffin-embedded samples on cohorts of solid tumors i.e. non-small cell lung cancer (NSCLC, n=45), stomach tumor (n=76), colorectal cancer (CRC, n=103), head and neck tumor (HNSCC, n=68), pancreatic tumors (n=77) and renal cell carcinoma (RCC, n=75), we observed NKp46+ NK cells in the large majority of cancer types (especially in RCC, HNSCC and stomach cancers). CD8+ T cells were found at significantly higher densities in all tumor types. In another cohort of HNSCC samples (n=60), higher proportions of CD94+ lymphocytes were found within the tumor islets both in the primary tumors and in the metastatic lymph nodes. In addition, in CRC patients with liver metastasis (n=101), high CD94+ cell densities were associated with poor overall survival. These data suggest that NKG2A blockade might unleash NK and T cells that are present in close contact to tumor cells. As previously shown, we confirmed that CD94-NKG2A ligand, HLA-E, was expressed by tumor cells in the large majority of solid tumor. In addition, high PD-L1 expressions were observed in NSCLC, stomach tumors, CRC and HNSCC. Flow cytometry analyses revealed that NK and CD8+ T cells co-expressing NKG2A and PD-1 were more numerous in tumor compared to matched peripheral blood and adjacent tissues of NSCLC and HNSCC patients. To mimic the “NKG2A+PD-1+” TILs phenotype, chronic stimulation of peripheral blood cells from healthy volunteers was performed using IL-15. The conditions led to the induction of NKG2A and PD-1 on NK and antigen-specific CD8+ T cell subsets. These effector cells were then co-cultured with tumor cell lines expressing HLA-E +/- PD-L1. We showed that monalizumab, a first-in class anti-NKG2A Ab, combined with durvalumab resulted in higher responses (CD107 mobilization and IFN-γ production) compared to each Ab alone. These data were confirmed in a syngeneic mouse model where both NK and CD8+ T cells were found to be involved in tumor rejection. Together, these data confirm that blocking NKG2A can potentiate the anti-tumor efficacy of PD-1 inhibitors and support the rationale for ongoing clinical trials investigating the monalizumab/durvalumab combination (NCT02671435 and NCT03088059).

Citation Format: Caroline Soulas, Romain Remark, Vedran Brezar, Julie Lopez, Elodie Bonnet, Flavien Caraguel, Ana Lalanne, Caroline Hoffmann, Caroline Denis, Thomas Arnoux, Clarisse Caillet, Arnaud Dujardin, Guillaume Habif, Olivier Lantz, Cécile Bonnafous, Eric Vivier, Pascale Andre. Combination of monalizumab and durvalumab as a potent immunotherapy treatment for solid human cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2714.

Abstract 1690: NKG2A immune checkpoint blockade potentiates cetuximab induced ADCC in head and neck cancer preclinical model

Monalizumab (IPH2201) is a first-in-class humanized IgG4 targeting NKG2A (Natural Killer Group 2A), which is expressed as a heterodimer with CD94 at the surface of subsets of NK (Natural Killer) cells, γδ T cells and tumor infiltrating CD8+ T cells. This inhibitory receptor binds to HLA-E (Human Leukocytes Antigen-E) molecules that are frequently up-regulated on human cancer cells, preventing from killing by NKG2A+ immune cells. HLA-E is expressed on most of the patients with Head and Neck Squamous Cell Cancer (HNSCC). Monalizumab blocks the binding of CD94/NKG2A to HLA-E, reducing inhibitory signaling thereby unleashing NK and T cell responses. High expression of EGFR occurs in most epithelial malignancies and particularly in HNSCC and is associated with poor prognosis. The anti-EGFR monoclonal antibody cetuximab (Ctx) is thought to act through blocking oncogenic signaling and by inducing Fcγ receptor-mediated antibody dependent cell cytotoxicity (ADCC) which involves human NK cells. We investigated ex vivo and in vitro the rationale of combining monalizumab with Ctx in the treatment of oral cancers. We first analyzed formalin-fixed paraffin-embedded samples of HNSCC patients by immunohistochemistry (n=65). We confirmed that HLA-E was expressed on carcinoma cells in all patients. We also observed that most of the tumors were highly infiltrated by CD8+ T cells both in the tumor beds and in the stroma and that the majority of tumors were also infiltrated by NKp46+ NK cells in higher numbers in the non-metastatic tumors. Interestingly, HNSCC was found as being one of the tumor types with the highest NKp46+ cell density as compared with renal cell carcinoma, non-small cell lung cancer, colorectal cancer or pancreatic tumors. Moreover CD94+ lymphocytes were detected in the stroma and tumor beds in close contact to tumor cells in about half of the patients. Using multicolor flow cytometry, NK cells and CD8+ T cells from tumor and non-involved adjacent tissues, metastatic lymph nodes and peripheral blood from patients relapsing post-chemotherapy were characterized for expression of activating and inhibitory receptors. Interestingly, NKG2A expression was higher on tumor infiltrating NK cells (CD56dim or CD56bright) and CD8+ T cell compared to the one observed in non-involved adjacent tissue, metastatic lymph node or blood. In vitro, monalizumab increased CD107 mobilization and CD137 upregulation on NKG2A+ NK cells in response to HNSCC cell lines with endogenous HLA-E expression and enhanced Ctx-mediated ADCC in a dose dependent manner. Altogether, these data support the rationale for investigating monalizumab in HNSCC patients and in combination with cetuximab in clinical trials (NCT02643550).

Citation Format: Caroline Soulas, Ana Lalanne, Cécile Bonnafous, Caroline Hoffman, Elodie Bonnet, Arnaud Dujardin, Violette Breso, Mathieu Bléry, Olivier Lantz, Romain Remark, Eric Vivier, Pascale Andre. NKG2A immune checkpoint blockade potentiates cetuximab induced ADCC in head and neck cancer preclinical model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1690.

RAF/MEK/extracellular signal-related kinase pathway suppresses dendritic cell migration and traps dendritic cells in Langerhans cell histiocytosis lesions

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia characterized by granulomatous lesions containing pathological CD207⁺ dendritic cells (DCs) with constitutively activated mitogen-activated protein kinase (MAPK) pathway signaling. Approximately 60% of LCH patients harbor somatic BRAFV600E mutations localizing to CD207⁺ DCs within lesions. However, the mechanisms driving BRAFV600E⁺ LCH cell accumulation in lesions remain unknown. Here we show that sustained extracellular signal-related kinase activity induced by BRAFV600E inhibits C-C motif chemokine receptor 7 (CCR7)-mediated DC migration, trapping DCs in tissue lesions. Additionally, BRAFV600E increases expression of BCL2-like protein 1 (BCL2L1) in DCs, resulting in resistance to apoptosis. Pharmacological MAPK inhibition restores migration and apoptosis potential in a mouse LCH model, as well as in primary human LCH cells. We also demonstrate that MEK inhibitor-loaded nanoparticles have the capacity to concentrate drug delivery to phagocytic cells, significantly reducing off-target toxicity. Collectively, our results indicate that MAPK tightly suppresses DC migration and augments DC survival, rendering DCs in LCH lesions trapped and resistant to cell death.

Identification of unique neoantigen qualities in long-term survivors of pancreatic cancer

Pancreatic ductal adenocarcinoma is a lethal cancer with fewer than 7% of patients surviving past 5 years. T-cell immunity has been linked to the exceptional outcome of the few long-term survivors, yet the relevant antigens remain unknown. Here we use genetic, immunohistochemical and transcriptional immunoprofiling, computational biophysics, and functional assays to identify T-cell antigens in long-term survivors of pancreatic cancer. Using whole-exome sequencing and in silico neoantigen prediction, we found that tumours with both the highest neoantigen number and the most abundant CD8+ T-cell infiltrates, but neither alone, stratified patients with the longest survival. Investigating the specific neoantigen qualities promoting T-cell activation in long-term survivors, we discovered that these individuals were enriched in neoantigen qualities defined by a fitness model, and neoantigens in the tumour antigen MUC16 (also known as CA125). A neoantigen quality fitness model conferring greater immunogenicity to neoantigens with differential presentation and homology to infectious disease-derived peptides identified long-term survivors in two independent datasets, whereas a neoantigen quantity model ascribing greater immunogenicity to increasing neoantigen number alone did not. We detected intratumoural and lasting circulating T-cell reactivity to both high-quality and MUC16 neoantigens in long-term survivors of pancreatic cancer, including clones with specificity to both high-quality neoantigens and predicted cross-reactive microbial epitopes, consistent with neoantigen molecular mimicry. Notably, we observed selective loss of high-quality and MUC16 neoantigenic clones on metastatic progression, suggesting neoantigen immunoediting. Our results identify neoantigens with unique qualities as T-cell targets in pancreatic ductal adenocarcinoma. More broadly, we identify neoantigen quality as a biomarker for immunogenic tumours that may guide the application of immunotherapies.

Abstract 334: PTEN-L regulates epithelial growth and macrophage function

PTEN is among the most frequently mutated and deleted tumor suppressor genes in many malignancies, including breast cancer. An alternatively translated long form of PTEN, termed PTEN-L, has divergent functionality from PTEN, although its function at the organism level has not been studied. Here, we report a knockout mouse with specific ablation of PTEN-L expression but intact expression of PTEN. These mice display mammary ductal hyperplasia characterized by increased luminal growth and increased numbers of macrophages in the surrounding stroma. Macrophages are particularly affected by PTEN-L loss, with significant changes to their secretomes and functional deficiencies in clearing bacterial infections, consistent with a shift toward an M2-like polarization. Overall, these findings demonstrate that PTEN-L has unique functions in regulating mammary epithelial growth and macrophage functionality that are independent of canonical PTEN.

Citation Format: Andrew L. Wolfe, Benjamin D. Hopkins, Sebastián A. Riquelme, Kipyegon Kitur, Sait Ozturk, Kyeongah Kang, Romain Remark, Adeeb Rahman, Chyuan-Sheng Lin, Miriam Merad, Matthias Szabolcs, Shu-Hsia Chen, Alice Prince, Ramon Parsons. PTEN-L regulates epithelial growth and macrophage function [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 334. doi:10.1158/1538-7445.AM2017-334

Innate Immune Landscape in Early Lung Adenocarcinoma by Paired Single-Cell Analyses

To guide the design of immunotherapy strategies for patients with early stage lung tumors, we developed a multiscale immune profiling strategy to map the immune landscape of early lung adenocarcinoma lesions to search for tumor-driven immune changes. Utilizing a barcoding method that allows a simultaneous single-cell analysis of the tumor, non-involved lung, and blood cells, we provide a detailed immune cell atlas of early lung tumors. We show that stage I lung adenocarcinoma lesions already harbor significantly altered T cell and NK cell compartments. Moreover, we identified changes in tumor-infiltrating myeloid cell (TIM) subsets that likely compromise anti-tumor T cell immunity. Paired single-cell analyses thus offer valuable knowledge of tumor-driven immune changes, providing a powerful tool for the rational design of immune therapies. VIDEO ABSTRACT.

Abstract 439: High Dimensional Single-Cell Immune Contexture of Human Atherosclerotic Plaques and Blood

Atherosclerosis is a disease characterized by immune infiltration of the arterial wall in response to tissue damage and systemic inflammation. In the era of precision medicine, is essential to gain insights on immune contexture of atherosclerotic tissue taking into account disease-specific cell variation in patients. We applied high-dimensional technologies for the analysis of multiple parameters at the single-cell level in clinical samples of patients undergoing carotid endatherectomy (CEA, n=15). Using time-of-flight mass-cytometry (CyTOF), we simultaneously analyzed 32 parameters at the single-cell level in peripheral blood mononuclear cells (PBMCs) and atherosclerotic-tissue associated immune cells of the same patient. Using viSNE, we mapped single-cell heterogeneity into two dimensions to discriminate PBMCs and tissue-associated CD45+ immune cells. Next, we employed Phenograph to cluster cells into phenotypically related populations, which were annotated based on canonical marker expression patterns. We identified several major immune subsets including two subsets of macrophages (CD163 low and CD163 high ), monocytes, dendritic cells (DCs), B and T cells. The most prevalent CD45+ cells identified in atherosclerotic tissue were CD4 + (25.8%) and CD8 + (25.2%) T cells, macrophages (12.8%), monocytes (7.7%) and B (2.1%) cells. Using a regression analysis similar to that employed by CITRUS, we determined that macrophages and a subset of CD8 T cells characterized by low expression of CD127 were selectively enriched in tissue vs. blood. Multiplexed immunohistochemistry confirmed that T cells comprised a major portion of the CD45+ cells in atherosclerotic tissue, even more abundant than macrophages. This study of deep phenotyping across-atherosclerotic tissue and blood demonstrate a significant T cell tissue infiltration of a specific subset of CD8 T cells. This suggests that adaptive T cell immunity plays a critical role in advanced atherosclerosis. The extension of this systems biology analysis pipeline to larger datasets can improve our understanding of the core mechanisms of chronic inflammation in atherosclerosis.

Host-Protozoan Interactions Protect from Mucosal Infections through Activation of the Inflammasome

While conventional pathogenic protists have been extensively studied, there is an underappreciated constitutive protist microbiota that is an integral part of the vertebrate microbiome. The impact of these species on the host and their potential contributions to mucosal immune homeostasis remain poorly studied. Here, we show that the protozoan Tritrichomonas musculis activates the host epithelial inflammasome to induce IL-18 release. Epithelial-derived IL-18 promotes dendritic cell-driven Th1 and Th17 immunity and confers dramatic protection from mucosal bacterial infections. Along with its role as a "protistic" antibiotic, colonization with T. musculis exacerbates the development of T-cell-driven colitis and sporadic colorectal tumors. Our findings demonstrate a novel mutualistic host-protozoan interaction that increases mucosal host defenses at the cost of an increased risk of inflammatory disease.

Immune contexture and histological response after neoadjuvant chemotherapy predict clinical outcome of lung cancer patients

There is now growing evidence that the immune contexture influences cancer progression and clinical outcome of patients with non-small cell lung cancer (NSCLC). If chemotherapy is widely used to treat patients with advanced-stage NSCLC, it remains unclear how it could modify the immune contexture and impact its prognostic value. Here, we analyzed two retrospective cohorts, respectively composed of 122 stage III-N2 NSCLC patients treated with chemotherapy before surgery and 39 stage-matched patients treated by surgery only. In patients treated with neoadjuvant chemotherapy, the histological characteristics, the expression of PD-L1 protein, and the tumor immune microenvironment (CD8⁺ T cells, DC-LAMP⁺ mature dendritic cells, and CD68⁺ macrophages) were evaluated and their prognostic value assessed together with standard clinical parameters. By analyzing pre- and post-treatment specimens, we did not find any changes in the PD-L1 expression. We also found that the tumor immune contexture in patients treated with neoadjuvant chemotherapy exhibited a similar pattern that the one found in chemotherapy-naive patients, with comparable densities of tumor-infiltrating CD8⁺ and DC-LAMP⁺ cells and a similar spatial organization. The percentage of residual viable tumor cells and the immune pattern (CD8⁺ and DC-LAMP⁺ cell densities) were significantly associated with the clinical outcome and allowed the identification of short- and long-term survivors, respectively. In multivariate analysis, the immune pattern was found to be the strongest independent prognostic factor. In conclusion, this study decrypts the complex interplay between cancer and immune cells in patients undergoing chemotherapy and supports potential beneficial synergistic effect of immunotherapy and chemotherapy.

Abstract A092: Comprehensive multidimensional analysis of the immune contexture in non-small cell lung cancer

Tumors form complex ecosystems that include normal epithelial cells, fibroblasts, blood and lymphatic vessels as well as structural components, and importantly, immune cells. The density, location, and organization of various tumor-infiltrating hematopoietic cells of myeloid and lymphoid origin can impact tumor growth, spreading, and clinical outcome of various cancers, including non-small cell lung cancer (NSCLC). Here, we propose to characterize the microenvironment of lung tumors using a unique set of matched fresh tissue single cell suspensions of tumor and normal lung, paraffin-embedded tissues, and peripheral blood plasma and cells obtained at time of surgery in the same patient. We aim to query mechanisms for local immunogenicity and immunosuppression of NSCLC, by defining interactions between tumor cells and various immune cell subsets in the local microenvironment, and by correlating these findings with presence of tumor-associated antigens (TAAs) and their capacity to elicit spontaneous local and systemic immune responses, as well as immune checkpoints known to impair immune responses. We applied multiplexed immunohistochemistry for formalin-fixed paraffin embedded cancer tissues (MICSSS method; n = 40), serological assays for immunogenicity of tumor antigens from plasma samples and supernatants of B cell cultures from the same patients (ELISA; n = 40), as well as mass cytometry on cell suspensions obtained from matched fresh specimens (CYTOF, n = 20) to (1) characterize the composition and organization of the immune microenvironment, (2) identify drivers of immunosuppression in NSCLC and (3) identify the expression profile of TAAs and B cell specificity in NSCLC. We found that TAAs, such as p53, NY-ESO-1, or ERG, were expressed by lung cancer cells in a subset of patients and that protein expression at the tumor site correlated with the antibody (Ab) response found in plasma of matched patients. While circulating plasma Ab titers did not appear to be correlated with the density of infiltrating B cells, potential associations with presence of tertiary-lymphoid structure, plasma cells (CD138+ cytokeratin− cells) or T follicular helper cells (CXCR5+ CD3+ CD8−) are currently being assessed. Association between molecular alterations and immune cell composition and location will also be discussed. We will also quantify expression of checkpoint molecules (PD-L1, VISTA and HHLA-2) on immune and tumor cells. The correlation between checkpoint inhibitor expression and immune cell densities and presence of immune responses will be presented, to assess whether immune cells contribute to the modulation of T cell effector functions. In conclusion, this study is the stepping-stone to a comprehensive understanding of the complex interactions between lung tumors and their immune microenvironment. By using novel multiplexed approaches, we intend to map the immune and antigenic landscape of human NSCLC, to identify mechanisms of early disease immunogenicity and immunosuppression, and to find new prognostic and predictive markers for the development of novel therapeutic strategies and immunotherapy trials in NSCLC.

Citation Format: Romain Remark, Yonit Lavin, Adeeb Rahman, Camille Bigenwald, Soma Kobayashi, Christian Becker, Raja Flores, Sacha Gnjatic, Miriam Merad. Comprehensive multidimensional analysis of the immune contexture in non-small cell lung cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A092.

Abstract B015: Expansion and activation of CD103+ dendritic cell progenitors at the tumor site transform tumor response to PD-L1 and BRAF inhibition

High numbers of melanoma lesions develop resistance to BRAF blockade or fail to respond to checkpoint inhibition therapy. Here we explored whether modulation of intratumoral antigen presenting cells (APCs) can help increase response to BRAF and checkpoint blockade in tamoxifen-induced Braf-mutant and B16 melanoma lesions. In both models, we found that CD103+ dendritic cells (DCs) were the only APCs that transported intact antigens to the lymph nodes and primed tumor-specific CD8+ T cells.

CD103+ DC expressed high PD-L1 levels in the tumor and were required to promote anti-tumoral effects upon blockade of the checkpoint ligand PD-L1; however, PD-L1 inhibition only led to partial responses and minimal accumulation of intratumoral CD8+ T cells. Strikingly, systemic administration of fms-like tyrosine kinase 3 ligand (Flt3L) followed by intratumoral poly I:C injections expanded and activated CD103+ DC progenitors in the tumor, enhancing responses to BRAF and PD-L1 blockade and protecting mice from tumor rechallenge in a T cell dependent manner. Thus, the paucity of activated CD103+ DCs in tumors limits checkpoint blockade efficacy and Flt3L-poly I:C therapy can transform clinical responses to checkpoint and BRAF blockade.

Salmon et al, 2016. Immunity, 44(4):924-38.

Citation Format: Hélène Salmon, Juliana Idoyaga, Adeeb Rahman, Romain Remark, Sacha Gnjatic, Nina Bhardwaj, Joshua Brody, Anna Karolina Palucka, Florent Ginhoux, Miriam Merad. Expansion and activation of CD103+ dendritic cell progenitors at the tumor site transform tumor response to PD-L1 and BRAF inhibition [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B015.

A Frameshift in CSF2RB Predominant Among Ashkenazi Jews Increases Risk for Crohn's Disease and Reduces Monocyte Signaling via GM-CSF

BACKGROUND & AIMS

Crohn's disease (CD) has the highest prevalence in Ashkenazi Jewish populations. We sought to identify rare, CD-associated frameshift variants of high functional and statistical effects.

METHODS

We performed exome sequencing and array-based genotype analyses of 1477 Ashkenazi Jewish individuals with CD and 2614 Ashkenazi Jewish individuals without CD (controls). To validate our findings, we performed genotype analyses of an additional 1515 CD cases and 7052 controls for frameshift mutations in the colony-stimulating factor 2-receptor β common subunit gene (CSF2RB). Intestinal tissues and blood samples were collected from patients with CD; lamina propria leukocytes were isolated and expression of CSF2RB and granulocyte-macrophage colony-stimulating factor-responsive cells were defined by adenomatous polyposis coli (APC) time-of-flight mass cytometry (CyTOF analysis). Variants of CSF2RB were transfected into HEK293 cells and the expression and functions of gene products were compared.

RESULTS

In the discovery cohort, we associated CD with a frameshift mutation in CSF2RB (P = 8.52 × 10(-4)); the finding was validated in the replication cohort (combined P = 3.42 × 10(-6)). Incubation of intestinal lamina propria leukocytes with granulocyte-macrophage colony-stimulating factor resulted in high levels of phosphorylation of signal transducer and activator of transcription (STAT5) and lesser increases in phosphorylation of extracellular signal-regulated kinase and AK straining transforming (AKT). Cells co-transfected with full-length and mutant forms of CSF2RB had reduced pSTAT5 after stimulation with granulocyte-macrophage colony-stimulating factor, compared with cells transfected with control CSF2RB, indicating a dominant-negative effect of the mutant gene. Monocytes from patients with CD who were heterozygous for the frameshift mutation (6% of CD cases analyzed) had reduced responses to granulocyte-macrophage colony-stimulating factor and markedly decreased activity of aldehyde dehydrogenase; activity of this enzyme has been associated with immune tolerance.

CONCLUSIONS

In a genetic analysis of Ashkenazi Jewish individuals, we associated CD with a frameshift mutation in CSF2RB. Intestinal monocytes from carriers of this mutation had reduced responses to granulocyte-macrophage colony-stimulating factor, providing an additional mechanism for alterations to the innate immune response in individuals with CD.

Expansion and Activation of CD103(+) Dendritic Cell Progenitors at the Tumor Site Enhances Tumor Responses to Therapeutic PD-L1 and BRAF Inhibition

Large numbers of melanoma lesions develop resistance to targeted inhibition of mutant BRAF or fail to respond to checkpoint blockade. We explored whether modulation of intratumoral antigen-presenting cells (APCs) could increase responses to these therapies. Using mouse melanoma models, we found that CD103(+) dendritic cells (DCs) were the only APCs transporting intact antigens to the lymph nodes and priming tumor-specific CD8(+) T cells. CD103(+) DCs were required to promote anti-tumoral effects upon blockade of the checkpoint ligand PD-L1; however, PD-L1 inhibition only led to partial responses. Systemic administration of the growth factor FLT3L followed by intratumoral poly I:C injections expanded and activated CD103(+) DC progenitors in the tumor, enhancing responses to BRAF and PD-L1 blockade and protecting mice from tumor rechallenge. Thus, the paucity of activated CD103(+) DCs in tumors limits checkpoint-blockade efficacy and combined FLT3L and poly I:C therapy can enhance tumor responses to checkpoint and BRAF blockade.

In-depth tissue profiling using multiplexed immunohistochemical consecutive staining on single slide

Despite remarkable recent achievements of immunotherapy strategies in cancer treatment, clinical responses remain limited to subsets of patients. Predictive markers of disease course and response to immunotherapy are urgently needed. Recent results have revealed the potential predictive value of immune cell phenotype and spatial distribution at the tumor site, prompting the need for multidimensional immunohistochemical analyses of tumor tissues. To address this need, we developed a sample-sparing, highly multiplexed immunohistochemistry technique based on iterative cycles of tagging, image scanning, and destaining of chromogenic substrate on a single slide. This assay, in combination with a newly developed automated digital landscaping solution, democratizes access to high-dimensional immunohistochemical analyses by capturing the complexity of the immunome using routine pathology standards. Applications of the method extend beyond cancer to screen and validate comprehensive panels of tissue-based prognostic and predictive markers, perform in-depth in situ monitoring of therapies, and identify targets of disease.

A multimodal imaging workflow to visualize metal mixtures in the human placenta and explore colocalization with biological response markers

Fetal exposure to essential and toxic metals can influence life-long health trajectories. The placenta regulates chemical transmission from maternal circulation to the fetus and itself exhibits a complex response to environmental stressors. The placenta can thus be a useful matrix to monitor metal exposures and stress responses in utero, but strategies to explore the biologic effects of metal mixtures in this organ are not well-developed. In this proof-of-concept study, we used laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to measure the distributions of multiple metals in placental tissue from a low-birth-weight pregnancy, and we developed an approach to identify the components of metal mixtures that colocalized with biological response markers. Our novel workflow, which includes custom-developed software tools and algorithms for spatial outlier identification and background subtraction in multidimensional elemental image stacks, enables rapid image processing and seamless integration of data from elemental imaging and immunohistochemistry. Using quantitative spatial statistics, we identified distinct patterns of metal accumulation at sites of inflammation. Broadly, our multiplexed approach can be used to explore the mechanisms mediating complex metal exposures and biologic responses within placentae and other tissue types. Our LA-ICP-MS image processing workflow can be accessed through our interactive R Shiny application 'shinyImaging', which is available at or through our laboratory's website, .

Immune biomarkers are more accurate in prediction of survival in ulcerated than in non-ulcerated primary melanomas

INTRODUCTION

Ulcerated melanomas may have a unique biology and microenvironment. We test whether markers of immune infiltration correlate with clinical outcome in ulcerated compared to non-ulcerated primary melanoma tumors.

METHODS

Sixty-two stage II-III cutaneous melanomas, 32 ulcerated and 30 non-ulcerated, were analyzed for tumor-infiltrating lymphocytes (TILs). Immunohistochemistry (IHC) was performed for CD2, a marker previously shown to correlate with overall survival (OS) and recurrence-free survival (RFS) in this patient population. IHC using antibody, VE1, to BRAF V600E was also performed on a subset of 41 tumors to assess the relationship of BRAF mutation to immune markers.

RESULTS

We found, using Cox regression models, that the presence of TILs was associated with improved OS (p = 0.034) and RFS (p = 0.002) in ulcerated melanoma tumors, but not in non-ulcerated melanoma (p = 0.632, 0.416). CD2 expression also was correlated with improved OS (p = 0.021) and RFS (p = 0.001) in ulcerated melanoma, but no relationship was seen in non-ulcerated melanoma (p = 0.427, 0.682). In this small population, BRAF status did not correlate with TILs or CD2+ count.

CONCLUSION

Our data show that immune markers including TILs and CD2 count correlate more closely with survival in ulcerated melanomas than that in non-ulcerated melanomas. We propose that immune biomarkers may be particularly relevant to ulcerated, as compared to non-ulcerated, melanomas and that this merits study in larger populations.

Jejunal T Cell Inflammation in Human Obesity Correlates with Decreased Enterocyte Insulin Signaling

In obesity, insulin resistance is linked to inflammation in several tissues. Although the gut is a very large lymphoid tissue, inflammation in the absorptive small intestine, the jejunum, where insulin regulates lipid and sugar absorption is unknown. We analyzed jejunal samples of 185 obese subjects stratified in three metabolic groups: without comorbidity, suffering from obesity-related comorbidity, and diabetic, versus 33 lean controls. Obesity increased both mucosa surface due to lower cell apoptosis and innate and adaptive immune cell populations. The preferential CD8αβ T cell location in epithelium over lamina propria appears a hallmark of obesity. Cytokine secretion by T cells from obese, but not lean, subjects blunted insulin signaling in enterocytes relevant to apical GLUT2 mislocation. Statistical links between T cell densities and BMI, NAFLD, or lipid metabolism suggest tissue crosstalk. Obesity triggers T-cell-mediated inflammation and enterocyte insulin resistance in the jejunum with potential broader systemic implications.

The non-small cell lung cancer immune contexture. A major determinant of tumor characteristics and patient outcome

Solid tumors, beyond mere accumulation of cancer cells, form a complex ecosystem consisting of normal epithelial cells, fibroblasts, blood and lymphatic vessels, structural components, and infiltrating hematopoietic cells including myeloid and lymphoid elements that impact tumor growth, tumor spreading, and clinical outcome. The composition of the immune microenvironment is diverse, including various populations of T cells, B cells, dendritic cells, natural killer cells, myeloid-derived suppressor cells, neutrophils, or macrophages. The immune contexture describes the density, location, and organization of these immune cells within solid tumors. In lung cancer, which is the deadliest type of cancer, and particularly in non-small cell lung cancer, its most prevalent form, reports have described some of the interactions between the tumor and the host. These data, in addition to articles on various types of tumors, provide a greater understanding of the tumor-host microenvironment interaction and stimulate the development of prognostic and predictive biomarkers, the identification of novel target antigens for therapeutic intervention, and the implementation of tools for long-term management of patients with cancer.

Abstract 1075: Molecular determinants of colon and renal cancers' immune contextures

In the vast majority of cancer types, as demonstrated and exemplified in colorectal cancer (CRC), a high density of CD8+ T cells in the tumor microenvironment correlates with a good prognosis for the patient. However, an opposite correlation has been reported in primary clear cell renal cell carcinoma (RCC) tumors. Our team studied the immune infiltrates of pulmonary metastases from CRC and RCC. We reported that despite the advanced stage of the disease in these patients, the immune infiltrate of pulmonary metastases remained a prognostic factor. As in the primary tumors, a high density of CD8+ T cells correlated with good prognosis for CRC metastases while it correlated with a bad prognosis for RCC metastases. These results suggest that the identity of the tumor cell is critical in shaping the immune contexture of a given tumor. We therefore investigated the molecular characteristics of the tumor cells which could be responsible for this opposite clinical impact in RCC versus CRC. First, we assessed the prognostic value associated with the expression of genes specific for different immune populations in several cohorts of primary CRC (n=177) and RCC tumors (n=72 and n=479), and confirmed the opposite impact of infiltrating lymphocyte densities on patient survival. In addition, RCC tumors showed a higher expression of genes related to inflammation, immunosuppression and angiogenesis. By comparing transcriptomic data from RCC and CRC cell lines, we observed that RCC tumor cells also expressed a significantly higher amount of these transcripts when compared to CRC tumor cells. Altogether, these results support the hypothesis that RCC malignant cells produce factors which are able to modify and determine the functional orientation of their immune microenvironment. Identifying which factors and pathways are critical for the RCC-related detrimental impact of CD8+ T cells on prognosis will be a major breakthrough, enabling the identification of new immunomodulatory drug targets and guide researchers and clinicians in immunotherapy protocols.

Citation Format: Etienne Becht, Nicolas A. Giraldo, Romain Remark, Aurelien de Reynies, Laetitia Lacroix, Diane Damotte, Catherine Sautès-Fridman, Wolf-Herman Fridman. Molecular determinants of colon and renal cancers' immune contextures. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1075. doi:10.1158/1538-7445.AM2014-1075

The immune microenvironment: a major player in human cancers

Cancer is a major public health issue and figures among the leading causes of death in the world. Cancer development is a long process, involving the mutation, amplification or deletion of genes and chromosomal rearrangements. The transformed cells change morphologically, enlarge, become invasive and finally detach from the primary tumor to metastasize in other organs through the blood and/or lymph. During this process, the tumor cells interact with their microenvironment, which is complex and composed of stromal and immune cells that penetrate the tumor site via blood vessels and lymphoid capillaries. All subsets of immune cells can be found in tumors, but their respective density, functionality and organization vary from one type of tumor to another. Whereas inflammatory cells play a protumoral role, there is a large body of evidence of effector memory T cells controlling tumor invasion and metastasis. Thus, high densities of memory Th1/CD8 cytotoxic T cells in the primary tumors correlate with good prognosis in most tumor types. Tertiary lymphoid structures, which contain mature dendritic cells (DC) in a T cell zone, proliferating B cells and follicular DC, are found in the tumor stroma and they correlate with intratumoral Th1/CD8 T cell and B cell infiltration. Eventually, tumors undergo genetic and epigenetic modifications that allow them to escape being controlled by the immune system. This comprehensive review describes the immune contexture of human primary and metastatic tumors, how it impacts on patient outcomes and how it could be used as a predictive biomarker and guide immunotherapies.

Presence of B cells in tertiary lymphoid structures is associated with a protective immunity in patients with lung cancer

RATIONALE

It is now well established that immune responses can take place outside of primary and secondary lymphoid organs. We previously described the presence of tertiary lymphoid structures (TLS) in patients with non-small cell lung cancer (NSCLC) characterized by clusters of mature dendritic cells (DCs) and T cells surrounded by B-cell follicles. We demonstrated that the density of these mature DCs was associated with favorable clinical outcome.

OBJECTIVES

To study the role of follicular B cells in TLS and the potential link with a local humoral immune response in patients with NSCLC.

METHODS

The cellular composition of TLS was investigated by immunohistochemistry. Characterization of B-cell subsets was performed by flow cytometry. A retrospective study was conducted in two independent cohorts of patients. Antibody specificity was analyzed by ELISA.

MEASUREMENTS AND MAIN RESULTS

Consistent with TLS organization, all stages of B-cell differentiation were detectable in most tumors. Germinal center somatic hypermutation and class switch recombination machineries were activated, associated with the generation of plasma cells. Approximately half of the patients showed antibody reactivity against up to 7 out of the 33 tumor antigens tested. A high density of follicular B cells correlated with long-term survival, both in patients with early-stage NSCLC and with advanced-stage NSCLC treated with chemotherapy. The combination of follicular B cell and mature DC densities allowed the identification of patients with the best clinical outcome.

CONCLUSIONS

B-cell density represents a new prognostic biomarker for NSCLC patient survival, and makes the link between TLS and a protective B cell-mediated immunity.

Dendritic cells in tumor-associated tertiary lymphoid structures signal a Th1 cytotoxic immune contexture and license the positive prognostic value of infiltrating CD8+ T cells

Tumor-infiltrating T cells, particularly CD45RO(+)CD8(+) memory T cells, confer a positive prognostic value in human cancers. However, the mechanisms that promote a protective T-cell response in the tumor microenvironment remain unclear. In chronic inflammatory settings such as the tumor microenvironment, lymphoid neogenesis can occur to create local lymph node-like structures known as tertiary lymphoid structures (TLS). These structures can exacerbate a local immune response, such that TLS formation in tumors may help promote an efficacious immune contexture. However, the role of TLS in tumors has yet to be investigated carefully. In lung tumors, mature dendritic cells (DC) present in tumor-associated TLS can provide a specific marker of these structures. In this study, we evaluated the influence of TLS on the characteristics of the immune infiltrate in cohorts of prospective and retrospective human primary lung tumors (n = 458). We found that a high density of mature DC correlated closely to a strong infiltration of T cells that are predominantly of the effector-memory phenotype. Moreover, mature DC density correlated with expression of genes related to T-cell activation, T-helper 1 (Th1) phenotype, and cytotoxic orientation. Lastly, a high density of TLS-associated DC correlated with long-term survival, which also allowed a distinction of patients with high CD8(+) T-cell infiltration but a high risk of death. Taken together, our results show how tumors infiltrated by TLS-associated mature DC generate a specific immune contexture characterized by a strong Th1 and cytotoxic orientation that confers the lowest risk of death. Furthermore, our findings highlight the pivotal function of TLS in shaping the immune character of the tumor microenvironment, in promoting a protective immune response mediated by T cells against cancer.

Characteristics and clinical impacts of the immune environments in colorectal and renal cell carcinoma lung metastases: influence of tumor origin

PURPOSE

If immune cells are involved in tumor surveillance and have a prognostic impact in most primary tumors, little is known about their significance in metastases. Because patients' survival is heterogeneous, even at metastatic stages, we hypothesized that immune cells may be involved in the control of metastases. We therefore characterized the tumor immune microenvironment and its prognostic value in colorectal and renal cell carcinoma (RCC) metastases, and compared it to primary tumors.

EXPERIMENTAL DESIGN

We analyzed by immunohistochemistry (n = 192) and qPCR (n = 32) the immune environments of colorectal carcinoma and RCC lung metastases.

RESULTS

Metastases from colorectal carcinoma and RCC have different immune infiltrates. Higher densities of DC-LAMP(+) mature dendritic cells (P < 0.0001) and lower densities of NKp46(+) NK cells (P < 0.0001) were observed in colorectal carcinoma as compared to RCC metastases, whereas densities of T cells were similar. High densities of CD8(+) and DC-LAMP(+) cells correlated with longer overall survival (OS) in colorectal carcinoma (P = 0.008) and shorter OS in RCC (P < 0.0001). High NK-cell densities were associated with improved survival in RCC (P = 0.002) but not in colorectal carcinoma. Densities of immune cells correlated significantly from primary to relapsing metastases for the same patient. A TH1 orientation was found in colorectal carcinoma metastases, whereas a heterogeneous immune gene expression was found in RCC metastases.

CONCLUSIONS

Our results show a major prognostic value of the immune pattern (CD8(+)/DC-LAMP(+) cell densities) in colorectal carcinoma and RCC, reproducible from primary to metastatic tumors, although with opposite clinical impacts, and highlight the role of the tumor cell in shaping its immune environment.

Abstract LB-497: Primary tumor localization determines the metastatic immune profile

Primary tumor localization determines the metastatic immune profile Background Most cancer patients die from their metastatic disease and not from their primary tumor. However, little is known on the immune microenvironment of metastatic lesions and on its impact on clinical outcome. Indeed, the immune pattern of the tumor microenvironment has been recently identified as being a major prognostic factor in primary tumors. Thus, a high density of memory T cells with a Th1 and CD8 cytotoxic orientation is beneficial in many cancers. However, there are a few exceptions since CD8+ T cells have been reported to be associated with bad prognosis in renal cell carcinoma. The question of the respective roles of the tumor cell and organ microenvironment to explain these differences has not been addressed. Methods We studied the density and organization of tumor-infiltrating immune cells (CD3+, CD8+, Foxp3+, granzyme B+, NK cells and mature DCs) in retrospective cohorts of primary and lung metastases of colorectal cancer (CRC, n=124) and renal cell carcinoma (RCC, n=55) by immunohistochemistry. We investigated by qPCR the gene expression levels related to immune populations and their functions in the lung metastases from 19 CRC and 12 RCC. Biological data's were compared to clinical data's and patient's outcome. Results The cell composition (CD3+, CD4+ and Foxp3+ T cells, mature DCs and NK cells) and organization (tertiary lymphoid structures) of the immune infiltrate in metastases depend on the origin of the primary tumor. In both cases (colorectal cancer and renal cell carcinoma lung metastases), the density of CD8+ T cells and mature DCs appeared to be strongest prognosticator of patient's survival as reported for many primary tumors, but with opposite impact. High densities of mature DCs and CD8+ cells correlate with good overall survival in lung metastases of colorectal cancer and with poor survival in lung metastases of renal cell cancer. In the latter, a strong Th2 and inflammatory context was present associated with a strong Th1 polarization. Conclusions Altogether, our data demonstrate that the immune pattern depends on the tumor origin and has a major prognostic role in advanced cancer stages with an impact on patient therapeutic management. We demonstrated also the complexity of the immune response polarization and its impact upon tumor immune surveillance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-497. doi:1538-7445.AM2012-LB-497