Development of [89Zr]Zr-hCD103.Fab01A and [68Ga]Ga-hCD103.Fab01A for PET imaging to noninvasively assess cancer reactive T cell infiltration: Fab-based CD103 immunoPET

BACKGROUND

CD103 is an integrin specifically expressed on the surface of cancer-reactive T cells. The number of CD103+ T cells significantly increases during successful immunotherapy and might therefore be an attractive biomarker for noninvasive PET imaging of immunotherapy response. Since the long half-life of antibodies preclude repeat imaging of CD103+ T cell dynamics early in therapy, we therefore here explored PET imaging with CD103 Fab fragments radiolabeled with a longer (89Zr) and shorter-lived radionuclide (68Ga).

METHODS

Antihuman CD103 Fab fragment Fab01A was radiolabeled with 89Zr or 68Ga, generating [89Zr]Zr-hCD103.Fab01A and [68Ga]Ga-hCD103.Fab01A, respectively. In vivo evaluation of these tracers was performed in male nude mice (BALB/cOlaHsd-Foxn1nu) with established CD103-expressing CHO (CHO.CD103) or CHO-wildtype (CHO.K1) xenografts, followed by serial PET imaging and ex vivo bio-distribution.

RESULTS

[89Zr]Zr-hCD103.Fab01A showed high tracer uptake in CD103+ xenografts as early as 3 h post-injection. However, the background signal remained high in the 3- and 6-h scans. The background was relatively low at 24 h after injection with sufficient tumor uptake. [68Ga]Ga-hCD103.Fab01Ashowed acceptable uptake and signal-to-noise ratio in CD103+ xenografts after 3 h, which decreased at subsequent time points.

CONCLUSION

[89Zr]Zr-hCD103.Fab01A demonstrated a relatively low background and high xenograft uptake in scans as early as 6 h post-injection and could be explored for repeat imaging during immunotherapy in clinical trials. 18F or 64Cu could be explored as alternative to 68Ga in optimizing half-life and radiation burden of the tracer.

Design, Synthesis, and Biological Evaluation of 2-Hydroxy-4-phenylthiophene-3-carbonitrile as PD-L1 Antagonist and Its Comparison to Available Small Molecular PD-L1 Inhibitors

In search of a potent small molecular PD-L1 inhibitor, we designed and synthesized a compound based on a 2-hydroxy-4-phenylthiophene-3-carbonitrile moiety. Ligand's performance was tested in vitro and compared side-by-side with a known PD-L1 antagonist with a proven bioactivity BMS1166. Subsequently, we modified both compounds to allow ¹⁸F labeling that could be used for PET imaging. Radiolabeling, which is used in drug development and diagnosis, was applied to investigate the properties of those ligands and test them against tissue sections with diverse expression levels of PD-L1. We confirmed biological activity toward hPD-L1 for this inhibitor, comparable with BMS1166, while holding enhanced pharmacological properties.

Development of 89Zr-anti-CD103 PET imaging for non-invasive assessment of cancer reactive T cell infiltration

PURPOSE

CD103, an integrin specifically expressed on the surface of cancer-reactive T cells, is significantly increased during successful immunotherapy across human malignancies. In this study, we describe the generation and zirconium-89 (⁸⁹Zr) radiolabeling of monoclonal antibody (mAb) clones that specifically recognize human CD103 for non-invasive immune positron-emission tomography (PET) imaging of T cell infiltration as potential biomarker for effective anticancer immune responses.

EXPERIMENTAL DESIGN

First, to determine the feasibility of anti-CD103 immuno-PET to visualize CD103-positive cells at physiologically and clinically relevant target densities, we developed an ⁸⁹Zr-anti-murine CD103 PET tracer. Healthy, non-tumor bearing C57BL/6 mice underwent serial PET imaging after intravenous injection, followed by ex vivo biodistribution. Tracer specificity and macroscopic tissue distribution were studied using autoradiography combined with CD103 immunohistochemistry. Next, we generated and screened six unique mAbs that specifically target human CD103 positive cells. Optimal candidates were selected for ⁸⁹Zr-anti-human CD103 PET development. Nude mice (BALB/cOlaHsd-Foxn1nu) with established CD103 expressing Chinese hamster ovary (CHO) or CHO wild-type xenografts were injected with ⁸⁹Zr-anti-human CD103 mAbs and underwent serial PET imaging, followed by ex vivo biodistribution.

RESULTS

⁸⁹Zr-anti-murine CD103 PET imaging identified CD103-positive tissues at clinically relevant target densities. For human anti-human CD103 PET development two clones were selected based on strong binding to the CD103⁺ CD8⁺ T cell subpopulation in ovarian cancer tumor digests, non-overlapping binding epitopes and differential CD103 blocking properties. In vivo, both ⁸⁹Zr-anti-human CD103 tracers showed high target-to-background ratios, high target site selectivity and a high sensitivity in human CD103 positive xenografts.

CONCLUSION

CD103 immuno-PET tracers visualize CD103 T cells at relevant densities and are suitable for future non-invasive assessment of cancer reactive T cell infiltration.

Tumor infiltrating CD8/CD103/TIM-3-expressing lymphocytes in epithelial ovarian cancer co-express CXCL13 and associate with improved survival

Reactivation of tumor infiltrating T lymphocytes (TILs) with immune checkpoint inhibitors or co-stimulators has proven to be an effective anti-cancer strategy for a broad range of malignancies. However, epithelial ovarian cancer (EOC) remains largely refractory to current T cell-targeting immunotherapeutics. Therefore, identification of novel immune checkpoint targets and biomarkers with prognostic value for EOC is warranted. Combining multicolor immunofluorescent staining’s with single cell RNA-sequencing analysis, we here identified a TIM-3/CXCL13-positive tissue-resident memory (CD8/CD103-positive) T cell (Trm) population in EOC. Analysis of a cohort of ~175 patients with high-grade serous EOC revealed TIM-3-positive Trm were significantly associated with improved patient survival. As CXCL13-positive CD8-positive T cells have been strongly linked to patient response to anti-PD1 immune checkpoint blockade, combinatorial TIM-3 and PD-1 blockade therapy may be of interest for the (re)activation of anti-cancer immunity in EOC.

Expression of CD39 Identifies Activated Intratumoral CD8+ T Cells in Mismatch Repair Deficient Endometrial Cancer

Simple Summary

Identification of human cancer-reactive CD8+ T cells is crucial for the stratification of patients for immunotherapy and determination of immune-therapeutic effects. Here, we report on the CD103− CD39+ subset of CD8+ T cells in tumors and reveal this subset to be activated and likely tumor-reactive. Our data further suggest that TGF-β signaling in the tumor micro-environment causes the differentiation of these recently activated CD103− CD39+ CD8+ T cells towards a CD39+ CD103+ tissue-resident memory-like phenotype.

Abstract

Identification of human cancer-reactive CD8+ T cells is crucial for the stratification of patients for immunotherapy and determination of immune-therapeutic effects. To date, these T cells have been identified mainly based on cell surface expression of programmed cell death protein 1 (PD-1) or co-expression of CD103 and CD39. A small subset of CD103− CD39+ CD8+ T cells is also present in tumors, but little is known about these T cells. Here, we report that CD103− CD39+ CD8+ T cells from mismatch repair-deficient endometrial tumors are activated and characterized predominantly by expression of TNFRSF9. In vitro, transforming growth factor-beta (TGF-β) drives the disappearance of this subset, likely through the conversion of CD103− CD39+ cells to a CD103+ phenotype. On the transcriptomic level, T cell activation and induction of CD39 was associated with a number of tissue residence and TGF-β responsive transcription factors. Altogether, our data suggest CD39+ CD103− CD8+ tumor-infiltrating T cells are recently activated and likely rapidly differentiate towards tissue residence upon exposure to TGF-β in the tumor micro-environment, explaining their relative paucity in human tumors.

Combined STING levels and CD103+ T cell infiltration have significant prognostic implications for patients with cervical cancer

Activation of STimulator of INterferon Genes (STING) is important for induction of anti-tumor immunity. A dysfunctional STING pathway is observed in multiple cancer types and associates with poor prognosis and inferior response to immunotherapy. However, the association between STING and prognosis in virally induced cancers such as HPV-positive cervical cancer remains unknown. Here, we investigated the prognostic value of STING protein levels in cervical cancer using tumor tissue microarrays of two patient groups, primarily treated with surgery (n = 251) or radio(chemo)therapy (n = 255). We also studied CD103, an integrin that marks tumor-reactive cytotoxic T cells that reside in tumor epithelium and that is reported to associate with improved prognosis. Notably, we found that a high level of STING protein was an independent prognostic factor for improved survival in both the surgery and radio(chemo)therapy group. High infiltration of CD103+ T cells was associated with improved survival in the radio(chemo)therapy group. The combination of STING levels and CD103+ T cell infiltration is strongly associated with improved prognosis. We conclude that combining the prognostic values of STING and CD103 may improve the risk stratification of cervical cancer patients, independent from established clinical prognostic parameters.

Prognostic image-based quantification of CD8CD103 T cell subsets in high-grade serous ovarian cancer patients

CD103-positive tissue resident memory-like CD8+ T cells (CD8CD103 TRM) are associated with improved prognosis across malignancies, including high-grade serous ovarian cancer (HGSOC). However, whether quantification of CD8, CD103 or both is required to improve existing survival prediction and whether all HGSOC patients or only specific subgroups of patients benefit from infiltration, remains unclear. To address this question, we applied image-based quantification of CD8 and CD103 multiplex immunohistochemistry in the intratumoral and stromal compartments of 268 advanced-stage HGSOC patients from two independent clinical institutions. Infiltration of CD8CD103 immune cell subsets was independent of clinicopathological factors. Our results suggest CD8CD103 TRM quantification as a superior method for prognostication compared to single CD8 or CD103 quantification. A survival benefit of CD8CD103 TRM was observed only in patients treated with primary cytoreductive surgery. Moreover, survival benefit in this group was limited to patients with no macroscopic tumor lesions after surgery. This approach provides novel insights into prognostic stratification of HGSOC patients and may contribute to personalized treatment strategies in the future.

Association of homozygous variants of STING1 with outcome in human cervical cancer

DNA-sensing receptor Cyclic GMP-AMP Synthase (cGAS) and its downstream signaling effector STimulator of INterferon Genes (STING) have gained significant interest in the field of tumor immunology, as a dysfunctional cGAS-STING pathway is associated with poor prognosis and worse response to immunotherapy. However, studies so far have not taken into account the polymorphic nature of the STING-encoding STING1 gene. We hypothesized that the presence of allelic variance in STING1 would cause variation between individuals as to their susceptibility to cancer development, cancer progression, and potential response to (immuno)therapy. To start to address this, we defined the genetic landscapes of STING1 in cervical scrapings and investigated their corresponding clinical characteristics across a unique cohort of cervical cancer patients and compared them with independent control cohorts. Although we did not observe an enrichment of particular STING1 allelic variants in cervical cancer patients, we did find that the occurrence of homozygous variants HAQ/HAQ and R232H/R232H of STING1 were associated with both younger age of diagnosis and higher recurrence rate. These findings were accompanied by worse survival, despite comparable mRNA and protein levels of STING and numbers of infiltrated CD8+ T cells. Our findings suggest that patients with HAQ/HAQ and R232H/R232H genotypes may have a dysfunctional cGAS-STING pathway that fails to promote efficient anticancer immunity. Interestingly, the occurrence of these genotypes coincided with homozygous presence of the V48V variant, which was found to be individually associated with worse outcome. Therefore, we propose V48V to be further evaluated as a novel prognostic marker for cervical cancer.

Prognostic Integrated Image-Based Immune and Molecular Profiling in Early-Stage Endometrial Cancer

Optimum risk stratification in early-stage endometrial cancer combines clinicopathologic factors and the molecular endometrial cancer classification defined by The Cancer Genome Atlas (TCGA). It is unclear whether analysis of intratumoral immune infiltrate improves this. We developed a machine-learning, image-based algorithm to quantify density of CD8+ and CD103+ immune cells in tumor epithelium and stroma in 695 stage I endometrioid endometrial cancers from the PORTEC-1 and -2 trials. The relationship between immune cell density and clinicopathologic/molecular factors was analyzed by hierarchical clustering and multiple regression. The prognostic value of immune infiltrate by cell type and location was analyzed by univariable and multivariable Cox regression, incorporating the molecular endometrial cancer classification. Tumor-infiltrating immune cell density varied substantially between cases, and more modestly by immune cell type and location. Clustering revealed three groups with high, intermediate, and low densities, with highly significant variation in the proportion of molecular endometrial cancer subgroups between them. Univariable analysis revealed intraepithelial CD8+ cell density as the strongest predictor of endometrial cancer recurrence; multivariable analysis confirmed this was independent of pathologic factors and molecular subgroup. Exploratory analysis suggested this association was not uniform across molecular subgroups, but greatest in tumors with mutant p53 and absent in DNA mismatch repair-deficient cancers. Thus, this work identified that quantification of intraepithelial CD8+ cells improved upon the prognostic utility of the molecular endometrial cancer classification in early-stage endometrial cancer.

[Alcohol withdrawal delirium: What's new for an old disease?]

The management of alcohol withdrawal syndrome is a frequent work in both community medicine and hospital wards. One of the most severe complications of alcohol withdrawal is Delirium Tremens (DT). The purpose of this development is to update knowledge on this complication in terms of diagnosis, evaluation and therapeutic approaches. It also proposes a reflection on the trajectory of care during and after DT.

Transcriptional Activity and Stability of CD39+CD103+CD8+ T Cells in Human High-Grade Endometrial Cancer

Tumor-infiltrating CD8+ T cells (TIL) are of the utmost importance in anti-tumor immunity. CD103 defines tumor-resident memory T cells (TRM cells) associated with improved survival and response to immune checkpoint blockade (ICB) across human tumors. Co-expression of CD39 and CD103 marks tumor-specific TRM with enhanced cytolytic potential, suggesting that CD39+CD103+ TRM could be a suitable biomarker for immunotherapy. However, little is known about the transcriptional activity of TRM cells in situ. We analyzed CD39+CD103+ TRM cells sorted from human high-grade endometrial cancers (n = 3) using mRNA sequencing. Cells remained untreated or were incubated with PMA/ionomycin (activation), actinomycin D (a platinum-like chemotherapeutic that inhibits transcription), or a combination of the two. Resting CD39+CD103+ TRM cells were transcriptionally active and expressed a characteristic TRM signature. Activated CD39+CD103+ TRM cells differentially expressed PLEK, TWNK, and FOS, and cytokine genes IFNG, TNF, IL2, CSF2 (GM-CSF), and IL21. Findings were confirmed using qPCR and cytokine production was validated by flow cytometry of cytotoxic TIL. We studied transcript stability and found that PMA-responsive genes and mitochondrial genes were particularly stable. In conclusion, CD39+CD103+ TRM cells are transcriptionally active TRM cells with a polyfunctional, reactivation-responsive repertoire. Secondly, we hypothesize that differential regulation of transcript stability potentiates rapid responses upon TRM reactivation in tumors.

Deep immune profiling of ovarian tumors identifies minimal MHC-I expression after neoadjuvant chemotherapy as negatively associated with T-cell-dependent outcome

Epithelial Ovarian cancer (EOC) is the most lethal gynecological malignancy and has limited curative therapeutic options. Immunotherapy for EOC is promising, but clinical efficacy remains restricted to a small percentage of patients. Several lines of evidence suggest that the low response rate might be improved by combining immunotherapy with carboplatin and paclitaxel, the standard-of-care chemotherapy for EOC. Here, we assessed the immune contexture of EOC tumors, draining lymph nodes, and peripheral blood mononuclear cells during carboplatin/paclitaxel chemotherapy. We observed that the immune contexture of EOC patients is defined by the tissue of origin, independent of exposure to chemotherapy. Summarized, draining lymph nodes were characterized by a quiescent microenvironment composed of mostly non-proliferating naïve CD4 + T cells. Circulating T cells shared phenotypic features of both lymph nodes and tumor-infiltrating immune cells. Immunologically 'hot' ovarian tumors were characterized by ICOS, GITR, and PD-1 expression on CD4 + and CD8 + cells, independent of chemotherapy. The presence of PD-1 + cells in tumors prior to, but not after, chemotherapy was associated with disease-specific survival (DSS). Accordingly, we observed high MHC-I expression in tumors prior to chemotherapy, but minimal MHC-I expression in tumors after neoadjuvant chemotherapy, even though there were no differences in the number of tumor-infiltrating lymphocytes (TIL) in both groups. We therefore speculate that the TIL influx into the chemotherapy tumor microenvironment may be a consequence of the general inflammatory nature of chemotherapy-experienced tumors. Strategies to upregulate MHC-I during or after neoadjuvant chemotherapy may thus improve treatment outcome in these patients.

A Transcriptionally Distinct CXCL13+CD103+CD8+ T-cell Population Is Associated with B-cell Recruitment and Neoantigen Load in Human Cancer

The chemokine CXCL13 mediates recruitment of B cells to tumors and is essential for the formation of tertiary lymphoid structures (TLSs). TLSs are thought to support antitumor immunity and are associated with improved prognosis. However, it remains unknown whether TLSs are formed in response to the general inflammatory character of the tumor microenvironment, or rather, are induced by (neo)antigen-specific adaptive immunity. We here report on the finding that the TGFβ-dependent CD103⁺CD8⁺ tumor-infiltrating T-cell (TIL) subpopulation expressed and produced CXCL13. Accordingly, CD8⁺ T cells from peripheral blood activated in the presence of TGFβ upregulated CD103 and secreted CXCL13. Conversely, inhibition of TGFβ receptor signaling abrogated CXCL13 production. CXCL13⁺CD103⁺CD8⁺ TILs correlated with B-cell recruitment, TLSs, and neoantigen burden in six cohorts of human tumors. Altogether, our findings indicated that TGFβ plays a noncanonical role in coordinating immune responses against human tumors and suggest a potential role for CXCL13⁺CD103⁺CD8⁺ TILs in mediating B-cell recruitment and TLS formation in human tumors.

L1CAM expression in uterine carcinosarcoma is limited to the epithelial component and may be involved in epithelial-mesenchymal transition

Uterine carcinosarcoma (UCS) has been proposed as a model for epithelial-mesenchymal transition (EMT), a process characterized by a functional change facilitating migration and metastasis in many types of cancer. L1CAM is an adhesion molecule that has been involved in EMT as a marker for mesenchymal phenotype. We examined expression of L1CAM in UCS in a cohort of 90 cases from four different centers. Slides were immunohistochemically stained for L1CAM and scored in four categories (0%, < 10%, 10-50%, and > 50%). A score of more than 10% was considered positive for L1CAM. The median age at presentation was 68.6 years, and half of the patients (53.3%) presented with FIGO stage 1 disease. Membranous L1CAM expression was positive in the epithelial component in 65.4% of cases. Remarkably, expression was negative in the mesenchymal component. In cases where both components were intermingled, expression limited to the epithelial component was confirmed by a double stain for L1CAM and keratin. Expression of L1CAM did not relate to overall or disease-free survival. Our findings suggest L1CAM is either not a marker for the mesenchymal phenotype in EMT, or UCS is not a good model for EMT.

Abstract 4044: Draining lymph nodes in ovarian cancer patients have a naïve immune cell signature

Purpose: Ovarian cancer (OC) is characterized by an immunosuppressive tumor micro-environment (TME). We speculated that the effects of this immunosuppressive TME extends to the draining lymph nodes (DLNs), hampering induction of a proper anti-tumor immune response. To address this, we compared the immune cell composition in OC tumors and DLNs using extensive flow cytometry.

Experimental design: OC tumor (n=16) and DLN samples (n=13) were collected during surgery after obtaining informed consent from the patients. All tissue samples were subjected to enzymatic digestion and single cells were isolated by density gradient centrifugation. Eight-color flow cytometry panels were used to cover various T cell and myeloid cell markers. Statistical analysis was performed as appropriate.

Results: CD8+ cytotoxic T cells (p&lt;0.001) and T regulatory cells (Tregs, p&lt;0.05) were significantly enriched in the tumor compared to the DLNs, while there were more CD4+ T helper cells in the DLNs (p&lt;0.001). Interestingly, CD123+ plasmocytoid dendric cells (DCs) were largely absent from the tumor, whereas CD1a+ CD1c+ immature DCs (p&lt;0.001) were enriched in the TME. No difference between the tumor and DLNs was seen for CD11c+ myeloid DCs (mDC). However, within the mDC population there were more CD1c+ myeloid type 1 DC (p&lt;0.05) in the DLNs than tumor, but less CD1a+ myeloid type 2 DCs (p&lt;0.001), no difference was seen for iDCs. Tumoral T cells had an exhausted effector memory T cell signature, upregulating HLA-DR, the memory T cell marker CD45RO and the T cell suppressing and exhaustion markers, PD-1, PD-L1, and CD27. Notably, tumoral CD4+ T cells highly expressed the co-stimulatory markers CD28 and OX40. In the DLNs, all T cells were predominantly CD45RA+ CCR7+ naïve T cells, concurrently expressing CD27 and CD28. In the tumor and DLNs, Tregs highly expressed CTLA-4 and ICOS, while CD8+ and CD4+ T cells heterogeneously expressed these markers. The proliferation marker Ki67+ was expressed by tumoral T cells and by all Tregs. The transcription factor EOMES was mainly expressed by Ki67+ CD8+ T cells, while the transcription factor Tbet was expressed by CD8+ T cells, independent of Ki67-expression or location in tumor or DLN. DLNs were largely devoid of Ki67+ T cells, with the exception of Tregs.

Conclusions: Cancer can elicit an antigen-mediated immune response via the DLN. However, our data shows a naïve immune cell composition in the DLNs of OC, possibly due to the immunosuppressive effects of the TME extending to the DLNs.

Citation Format: Kim Brunekreeft, Fenne Komdeur, Hagma Workel, Florine Eggink, Annechien Plat, Refika Yigit, Harry Hollema, Evelien Duiker, Hans Nijman, Marco Bruyn. Draining lymph nodes in ovarian cancer patients have a naïve immune cell signature [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 4044.

CD103+ intraepithelial T cells in high-grade serous ovarian cancer are phenotypically diverse TCRαβ+ CD8αβ+ T cells that can be targeted for cancer immunotherapy

CD103+ tumor-infiltrating lymphocytes (TIL) have been linked to specific epithelial infiltration and a prolonged survival in high-grade serous epithelial ovarian cancer (HGSC). However, whether these cells are induced as part of an ongoing anti-HGSC immune response or represent non-specifically expanded resident or mucosal lymphocytes remains largely unknown. In this study, we first confirmed that CD103+ TIL from HGSC were predominantly localized in the cancer epithelium and were strongly correlated with an improved prognosis. We further demonstrate that CD103+ TIL were almost exclusively CD3+ TCRαβ+ CD8αβ+ CD4- T cells, but heterogeneously expressed T cell memory and differentiation markers. Activation of peripheral T cells in the presence of HGSC was sufficient to trigger induction of CD103 in over 90% of all CD8+ cells in a T cell receptor (TCR)- and TGFβR1-dependent manner. Finally, CD103+ TIL isolated from primary HGSC showed signs of recent activation and dominantly co-expressed key immunotherapeutic targets PD-1 and CD27. Taken together, our data indicate CD103+ TIL in HGSC are formed as the result of an adaptive anti-tumor immune response that might be reactivated by (dual) checkpoint inhibition.

Microsatellite instability derived JAK1 frameshift mutations are associated with tumor immune evasion in endometrioid endometrial cancer

JAK1 frameshift mutations may promote cancer cell immune evasion by impeding upregulation of the antigen presentation pathway in microsatellite unstable endometrial cancers (ECs). This study investigated the JAK1 mutation frequency, its functional implication in immune evasion and its prognostic significance in microsatellite unstable EC. Microsatellite instability and three microsatellite repeats within JAK1 were analyzed in 181 ECs. Sixty-two (34%) ECs showed microsatellite instability, of which 22 (35%) had a JAK1 mutation. LMP7, TAP1 and HLA class I protein expression and the presence of CD8-positive T-cells were analyzed in the microsatellite unstable ECs. JAK1 mutant microsatellite unstable ECs showed impaired upregulation of LMP7 (P=0.074) and HLA class I (P<0.001), validated using RNAseq data of the TCGA. TAP1 expression and presence of CD8-positive T-cells were not related to JAK1 mutations. In 198 additional microsatellite unstable ECs, the JAK1 mutation frequency was confirmed but no prognostic significance was found. For, JAK1 wildtype (n=135, 72%) and mutant (n=52, 28%) ECs, 10-year recurrence free rates were 84% and 77% (P=0.301). These observations show that JAK1 mutations are highly frequent in microsatellite unstable EC, not associated with survival, but are associated with impaired upregulation of LMP7 and HLA class I and may therefore facilitate immune escape.

The prognostic benefit of tumour-infiltrating Natural Killer cells in endometrial cancer is dependent on concurrent overexpression of Human Leucocyte Antigen-E in the tumour microenvironment

BACKGROUND

Human Leucocyte Antigen- E (HLA-E) has been reported as both a positive and negative prognostic marker in cancer. This apparent discrepancy may be due to opposing actions of HLA-E on tumour-infiltrating immune cells. Therefore, we evaluated HLA-E expression and survival in relation to the presence of intratumoural natural killer (NK) cells and cytotoxic T cells (CTLs).

METHODS

Tissue microarrays (TMAs) of endometrial tumours were used for immunohistochemical staining of parameters of interest. The combined impact of clinical, pathological and immune parameters on survival was analysed using log rank testing and Cox regression analyses.

RESULTS

Upregulation of HLA-E was associated with an improved disease-free and disease-specific survival in univariate analysis (HR 0.58 95% CI 0.37-0.89; HR 0.42 95% CI 0.25-0.73, respectively). In multivariate analysis, the presence of NK cells predicts survival with a hazard ratio (HR) 0.28 (95% confidence interval (CI) 0.09-0.91) when HLA-E expression is upregulated; but it is associated with a worse prognosis when HLA-E expression is normal (HR 13.43, 95% CI 1.70-106.14). By contrast, the prognostic benefit of T cells was not modulated by HLA-E expression.

CONCLUSIONS

Taken together, we demonstrate that the prognostic benefit of NK cells, but not T-cells, is influenced by HLA-E expression in endometrial cancer (EC) and propose a model to explain our observations.

CD103+ tumor-infiltrating lymphocytes are tumor-reactive intraepithelial CD8+ T cells associated with prognostic benefit and therapy response in cervical cancer

Human papilloma virus (HPV)-induced cervical cancer constitutively expresses viral E6/E7 oncoproteins and is an excellent target for T cell-based immunotherapy. However, not all tumor-infiltrating T cells confer equal benefit to patients, with epithelial T cells being superior to stromal T cells. To assess whether the epithelial T cell biomarker CD103 could specifically discriminate the beneficial antitumor T cells, association of CD103 with clinicopathological variables and outcome was analyzed in the TCGA cervical cancer data set (n = 304) and by immunohistochemistry (IHC) in an independent cohort (n = 460). Localization of CD103+ cells in the tumor was assessed by immunofluorescence. Furthermore, use of CD103 as a response biomarker was assessed in an in vivo E6/E7+ tumor model. Our results show that CD103 gene expression was strongly correlated with cytotoxic T cell markers (e.g. CD8/GZMB/PD1) in the TCGA series. In line with this, CD103+ cells in the IHC series co-expressed CD8 and were preferentially located in cervical tumor epithelium. High CD103+ cell infiltration was strongly associated with an improved prognosis in both series, and appeared to be a better predictor of outcome than CD8. Interestingly, the prognostic benefit of CD103 in both series seemed limited to patients receiving radiotherapy. In a preclinical mouse model, HPV E6/E7-targeted therapeutic vaccination in combination with radiotherapy increased the intratumoral number of CD103+ CD8+ T cells, providing a potential mechanistic basis for our results. In conclusion, CD103 is a promising marker for rapid assessment of tumor-reactive T cell infiltration of cervical cancers and a promising response biomarker for E6/E7-targeted immunotherapy.

Abstract 1687: Systemic immunological changes during first line chemotherapy in patients with high-grade serous ovarian cancer

Ovarian cancer remains the most lethal gynecological malignancy and new therapeutic strategies are urgently needed. High-grade serous ovarian cancer (HGSC), in particular, is associated with a five-year survival of only 40%. A promising new approach for treating HGSC is immunotherapy, which has resulted in complete and durable responses, albeit in a minority of patients. One potential approach for improving these response rates is by combining chemo- and immunotherapy. Indeed, carboplatin/taxol chemotherapy was shown to augment immune responses in cervical cancer patients by depleting circulating myeloid suppressor cells. As patients with HGSC are treated in first line with similar carboplatin/taxol chemotherapy, we explored the effects of chemotherapy on systemic immunity in HGSC patients. Within this prospective observational study, 75 patients with suspected ovarian cancer were included. Blood was collected at three different time points during first line chemotherapy treatment, namely: prior to chemotherapy, between the third and fourth cycle of chemotherapy and 4-6 weeks after the sixth cycle of chemotherapy. All patients received 6 cycles of carboplatin/taxol chemotherapy and cytoreductive surgery (either as primary debulking, or after 3 cycles of neo-adjuvant chemotherapy). Peripheral blood mononuclear cells were isolated and analyzed for a total of 36 immune markers using 9 flow cytometry panels, in total analyzing 49 immune cell subsets. Results were compared to an age-matched cohort consisting of women surgically treated for a benign disease, and a cohort of healthy young volunteers. 75 patients have been included so far from which 22 were diagnosed with benign disease, 3 were diagnosed with another malignancy, and 50 were diagnosed with OC. Of the 50 OC patients, 18 were diagnosed with HGSC and from 9 HGSC patients, multiple time points were available for analysis of chemotherapy-dependent changes in the immune cell subsets. All patients developed leukopenia as a result of chemotherapeutic treatment. Age-related changes in lymphocyte and myeloid cell subsets were observed in all HGSC patients and patients with benign disease. Chemotherapy-dependent depletion of myeloid cells was observed in a subset of patients. Depletion of myeloid subsets was equally distributed among monocytes, macrophages and dendritic cells. No HGSC- or chemotherapy-dependent changes in T cell subsets or migration and activation markers were observed. Taken together, we observed no major systemic changes in immune cell subsets during carboplatin/taxol chemotherapy treatment, suggesting that combined chemo-immunotherapeutic strategies could be feasible during first line treatment of HGSC.

Citation Format: Fenne L. Komdeur, Florine A. Eggink, Ninke Leffers, Hagma H. Workel, Kim L. Brunekreeft, Annechien Plat, Marco de Bruyn, Hans W. Nijman. Systemic immunological changes during first line chemotherapy in patients with high-grade serous ovarian cancer [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 1687. doi:10.1158/1538-7445.AM2017-1687

Mutagenesis of nisin's leader peptide proline strongly modulates export of precursor nisin

The lantibiotic nisin is produced by Lactococcus lactis as a precursor peptide comprising a 23 amino acid leader peptide and a 34 amino acid post-translationally modifiable core peptide. We previously demonstrated that the conserved FNLD part of the leader is essential for intracellular enzyme-catalyzed introduction of lanthionines in the core peptide and also for transporter-mediated export, whereas other positions are subject to large mutational freedom. We here demonstrate that, in the absence of the extracellular leader peptidase, NisP, export of precursor nisin via the modification and transporter enzymes, NisBTC, is strongly affected by multiple substitutions of the leader residue at position -2, but not by substitution of positions in the vicinity of this site. Export levels of precursor nisin increased by more than 70% for position -2 mutants Asp, Thr, Ser, Trp, Lys, Val and decreased more than 70% for Cys, His, Met. In a strain with leader peptidase, the Pro-2Lys and Pro-2Asp precursor nisins were less efficiently cleaved by NisP than wild type precursor nisin. Taken together, the wild type precursor nisin with a proline at position -2 allows balanced export and cleavage efficiencies by precursor nisin's transporter and leader peptidase.

Abstract A108: CD103+ intraepithelial T cells in high-grade serous ovarian cancer are phenotypically diverse TCRαβ+ CD8αβ+ T cells that can be targeted for cancer immunotherapy

Introduction: CD103+ tumor-infiltrating lymphocytes (TIL) have been linked to specific epithelial infiltration and a prolonged survival in epithelial malignancies. However, whether these cells are induced as part of an ongoing anti-tumor immune response or represent non-specifically expanded resident or mucosal lymphocytes remains largely unknown.

Methods: CD103+ TIL were quantified in a cohort of ovarian and endometrial cancer patients by immunohistochemistry. Localization of CD103+ cells and co-expression of CD103 with CD3, CD8, CD16 and FoxP3 was assessed by immunofluorescence. Further phenotyping and functional experiments of CD103+ cells was performed mainly by flow cytometry on primary tumor digests.

Summary of the Data: In this study, we first confirmed that CD103+ TIL from ovarian and uterine cancer were predominantly localized in the cancer epithelium and were strongly correlated with an improved prognosis. We further demonstrate that CD103+ TIL were almost exclusively CD3+ TCRαβ+ CD8αβ+ CD4- T cells, but heterogeneously expressed T cell memory and differentiation markers. Activation of peripheral T cells in the presence of HGSC was sufficient to trigger induction of CD103 in over 90% of all CD8+ cells in a T cell receptor (TCR)- and TGFβR1-dependent manner. Finally, CD103+ TIL isolated from primary ovarian and uterine tumors showed signs of recent activation and dominantly co-expressed key immunotherapeutic targets PD-1 and CD27.

Conclusion: Our data indicate CD103+ TIL are formed as the result of an adaptive anti-tumor immune response that might be reactivated by (dual) checkpoint inhibition.

Citation Format: Hans Nijman, Fenne Komdeur, Maartje Wouters, Hagma Workel, Kim Brunekreeft, Annechien Plat, Florine Eggink, Bea Wisman, Toos Daemen, Evelien Duiker, Harry Hollema, Marco de Bruyn. CD103+ intraepithelial T cells in high-grade serous ovarian cancer are phenotypically diverse TCRαβ+ CD8αβ+ T cells that can be targeted for cancer immunotherapy [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 A108.

Discovery, Production and Modification of Five Novel Lantibiotics Using the Promiscuous Nisin Modification Machinery

To find the right conditions to isolate natively expressed antimicrobial peptides from a wide range of different microorganisms can be a challenge. Here, we exploited a heterologous expression system to produce and characterize several novel lantibiotics. We identified 54 novel putative class I and class II lantibiotics after inspecting all publicly available prokaryotic genomes using the in-house developed mining tool BAGEL3. The genes encoding these new lantibiotics fused to the nisin leader peptide gene sequence were synthesized, and the constructs were plugged into the nisin expression and modification system. Using this approach 30 peptides could be expressed, 27 of which were dehydrated by NisBC on at least 1 predicted position. Good antimicrobial activity against several pathogenic bacteria could be demonstrated for 5 novel heterologously modified lantibiotics. Lantibiotics from Corynebacterium lipophiloflavum DSM 44291 and Streptococcus agalactiae ATCC 13813, named flavucin and agalacticin, respectively, were fully modified and displayed high antimicrobial activity. The efficiency of functional expression was significantly enhanced when we made use of the native nisin leader cleavage site, instead of an artificial factor Xa site. Thus, we describe an efficient way for heterologous production of active lantibiotics, facilitating a rapid identification of promising molecules.

Treatment Regimen, Surgical Outcome, and T-cell Differentiation Influence Prognostic Benefit of Tumor-Infiltrating Lymphocytes in High-Grade Serous Ovarian Cancer

PURPOSE

Tumor-infiltrating lymphocytes (TIL) are associated with a better prognosis in high-grade serous ovarian cancer (HGSC). However, it is largely unknown how this prognostic benefit of TIL relates to current standard treatment of surgical resection and (neo-)adjuvant chemotherapy. To address this outstanding issue, we compared TIL infiltration in a unique cohort of patients with advanced-stage HGSC primarily treated with either surgery or neoadjuvant chemotherapy.

EXPERIMENTAL DESIGN

Tissue microarray slides containing samples of 171 patients were analyzed for CD8(+) TIL by IHC. Freshly isolated CD8(+) TIL subsets were characterized by flow cytometry based on differentiation, activation, and exhaustion markers. Relevant T-cell subsets (CD27(+)) were validated using IHC and immunofluorescence.

RESULTS

A prognostic benefit for patients with high intratumoral CD8(+) TIL was observed if primary surgery had resulted in a complete cytoreduction (no residual tissue). By contrast, optimal (<1 cm of residual tumor) or incomplete cytoreduction fully abrogated the prognostic effect of CD8(+) TIL. Subsequent analysis of primary TIL by flow cytometry and immunofluorescence identified CD27 as a key marker for a less-differentiated, yet antigen-experienced and potentially tumor-reactive CD8(+) TIL subset. In line with this, CD27(+) TIL were associated with an improved prognosis even in incompletely cytoreduced patients. Neither CD8(+) nor CD27(+) cell infiltration was of prognostic benefit in patients treated with neoadjuvant chemotherapy.

CONCLUSIONS

Our findings indicate that treatment regimen, surgical result, and the differentiation of TIL should all be taken into account when studying immune factors in HGSC or, by extension, selecting patients for immunotherapy trials.

Prediction model for regional or distant recurrence in endometrial cancer based on classical pathological and immunological parameters

Background:

Adjuvant therapy increases disease-free survival in endometrial cancer (EC), but has no impact on overall survival and negatively influences the quality of life. We investigated the discriminatory power of classical and immunological predictors of recurrence in a cohort of EC patients and confirmed the findings in an independent validation cohort.

Methods:

We reanalysed the data from 355 EC patients and tested our findings in an independent validation cohort of 72 patients with EC. Predictors were selected and Harrell's C-index for concordance was used to determine discriminatory power for disease-free survival in the total group and stratified for histological subtype.

Results:

Predictors for recurrence were FIGO stage, lymphovascular space invasion and numbers of cytotoxic and memory T-cells. For high risk cancer, cytotoxic or memory T-cells predicted recurrence as well as a combination of FIGO stage and lymphovascular space invasion (C-index 0.67 and 0.71 vs 0.70). Recurrence was best predicted when FIGO stage, lymphovascular space invasion and numbers of cytotoxic cells were used in combination (C-index 0.82). Findings were confirmed in the validation cohort.

Conclusions:

In high-risk EC, clinicopathological or immunological variables can predict regional or distant recurrence with equal accuracy, but the use of these variables in combination is more powerful.

[Agranulocytosis and vasculitis in a cocaine addict: levamisole, the hidden culprit]

INTRODUCTION

Adulterants are compounds added to street drugs to increase profits for the seller. Levamisole, a veterinary antihelminthic agent, has become the most common adulterant of cocaine. The prevalence of levamisole in samples of cocaine is increasing. Levamisole can lead to neutropenia and to a dramatic vasculopathy and even vasculitis of small and medium-size blood vessels.

CASE REPORT

We here reported the first French case of levamisole related toxicity, due to cocaine use in a 50-year-old man, revealed by fever and agranulocytosis, high titters of antineutrophil cytoplasmic antibodies (ANCA), anticoagulant and positive Coombs tests. Outcome was slowly favorable with exposition withdrawal.

CONCLUSION

Clinicians should be aware that agranulocytosis or vasculitis or vasculopathy could be related to levamisole toxicity in individuals who use cocaine.