Signaling through the coinhibitory programmed death (PD)-1/PD-L1 pathway regulates T cell responses and can inhibit ongoing immune responses. Inflammation is a key process in the development of... Show moreSignaling through the coinhibitory programmed death (PD)-1/PD-L1 pathway regulates T cell responses and can inhibit ongoing immune responses. Inflammation is a key process in the development of atherosclerosis, the underlying cause for the majority of cardiovascular diseases. Dampening the excessive immune response that occurs during atherosclerosis progression by promoting PD-1/PD-L1 signaling may have a high therapeutic potential to limit disease burden. In this study we therefore aimed to assess whether an agonistic PD-1 antibody can diminish atherosclerosis development.Ldlr-/- mice were fed a western-type diet (WTD) while receiving 100 μg of an agonistic PD-1 antibody or control vehicle twice a week. Stimulation of the PD-1 pathway delayed the WTD-induced monocyte increase in the circulation up to 3 weeks and reduced T cell activation and proliferation. CD4+ T cell numbers in the atherosclerotic plaque were reduced upon PD-1 treatment. More specifically, we observed a 23% decrease in atherogenic IFNγ-producing splenic CD4+ T cells and a 20% decrease in cytotoxic CD8+ T cells, whereas atheroprotective IL-10 producing CD4+ T cells were increased with 47%. Furthermore, we found an increase in regulatory B cells, B1 cells and associated atheroprotective circulating oxLDL-specific IgM levels in agonistic PD-1-treated mice. This dampened immune activation following agonistic PD-1 treatment resulted in reduced atherosclerosis development (p < 0.05).Our data show that stimulation of the coinhibitory PD-1 pathway inhibits atherosclerosis development by modulation of T- and B cell responses. These data support stimulation of coinhibitory pathways as a potential therapeutic strategy to combat atherosclerosis. Show less
Cancer vaccines are aimed at raising an immune responses aganist defined tumor antigens. The formulation of a vaccine has a direct impact on the potency of the immune response generated. Cancer... Show moreCancer vaccines are aimed at raising an immune responses aganist defined tumor antigens. The formulation of a vaccine has a direct impact on the potency of the immune response generated. Cancer vaccines require particular effort in their formulation, as the immune system has to overcome immune suppression exerted by the tumor. In this thesis, different formulations to enhance cancer vaccine efficacy were explored. In the first part it is shown how chemical conjugation of antigen and adjuvant in form synthetic Toll-like receptor ligands represent a strategy to enahnce vaccine potency. Next, it is presented how the loading of peptide antigens onto dextran nanogel contributes to increase the breadth of the immune response induced. Lastly, a new DNA vaccine containing multiple tumor neoantigens was explored as a platform for personalized cancer vaccines. Together, these studies display how the formulation of cancer vaccines can be modified and optimized to achieve stronger therapeutic efficacy in the clinic. Show less
Type 1 Diabetes (T1D) is an auto-immune disease in which beta cells in the pancreas are killed by auto-reactive T-cells. Auto-reactive T-cells are activated by dendritic cells that present antigens... Show moreType 1 Diabetes (T1D) is an auto-immune disease in which beta cells in the pancreas are killed by auto-reactive T-cells. Auto-reactive T-cells are activated by dendritic cells that present antigens. Immunotherapy could reverse T1D, however. A case report of a T1D patient showed that after intravenous immunoglobulin treatment her insulin needs dropped completely. Similarly, the majority of T1D patients were insulin independent after autologous hematopoietic stem cell transplantation. As these therapies only showed incidental success or are a drastic reset of the immune system, respectively, other milder therapies were studied as well. Autologous tolerogenic dendritic cell therapy, for instance, is a reproducible, stable therapy and does not differ between T1D patients and healthy subjects. In addition, the author described that when mesenchymal stromal cells were activated, they were able to suppress an antigen-specific immune response, thereby potentiating them as an antigen-specific therapy besides their natural immunosuppressive nature. Activated mesenchymal stromal cells could also improve the islet of Langerhans’ microenvironment, as they secreted immunosuppressive and angiogenic factors. To conclude, the future of T1D therapies lies in finding a balance between suppressing the immune system and antigen-specific therapies combined with therapies that increase the vitality of beta cells. Show less
Buma, A.I.G.; Muller, M.; Vries, R. de; Sterk, P.J.; Noort, V. van der; Wolf-Lansdorf, M.; ... ; Heuvel, M.M. van den 2021
Objectives: Exhaled breath analysis by electronic nose (eNose) has shown to be a potential predictive biomarker before start of anti-PD-1 therapy in patients with non-small cell lung carcinoma ... Show moreObjectives: Exhaled breath analysis by electronic nose (eNose) has shown to be a potential predictive biomarker before start of anti-PD-1 therapy in patients with non-small cell lung carcinoma (NSCLC). We hypothesized that the eNose could also be used as an early monitoring tool to identify responders more accurately at early stage of treatment when compared to baseline. In this proof-of-concept study we aimed to definitely discriminate responders from non-responders after six weeks of treatment. Materials and Methods: This was a prospective observational study in patients with advanced NSCLC eligible for anti-PD-1 treatment. The efficacy of treatment was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 at 3-month follow-up. We analyzed SpiroNose exhaled breath data of 94 patients (training cohort n = 62, validation cohort n = 32). Data analysis involved signal processing and statistics based on Independent Samples T-tests and Linear Discriminant Analysis (LDA) followed by Receiver Operating Characteristic (ROC) analysis. Results: In the training cohort, a specificity of 73% was obtained at a 100% sensitivity level to identify objective responders. The Area Under the Curve (AUC) was 0.95 (CI: 0.89-1.00). In the validation cohort, these results were confirmed with an AUC of 0.97 (CI: 0.91-1.00). Conclusion: Exhaled breath analysis by eNose early during treatment allows for a highly accurate, non-invasive and low-cost identification of advanced NSCLC patients who benefit from anti-PD-1 therapy. Show less
In this thesis, the effects of a new form of immunotherapy was investigated and studied how it can be used against different types of cancers. The investigated immunotherapy is based on injecting... Show moreIn this thesis, the effects of a new form of immunotherapy was investigated and studied how it can be used against different types of cancers. The investigated immunotherapy is based on injecting nanoparticles loaded with various immunologically active molecules (immunomodulatory nanoparticles) that can modulate the immune system to attack cancer cells more efficiently. The effectiveness of this immunomodulatory nanoparticles have been studied on different mouse cancer models and investigated as a single treatment or in combination with other known therapies, such as chemotherapy, therapeutic cancer vaccination, or photodynamic therapy. Show less
Immunotherapies for cancer are an emerging class of therapeutic strategies which aim to treat cancer via augmentation of the immune system. Despite significant success of immunotherapies in the... Show moreImmunotherapies for cancer are an emerging class of therapeutic strategies which aim to treat cancer via augmentation of the immune system. Despite significant success of immunotherapies in the past decade, not all patients will respond to these treatments and the reasons why immunotherapies are successful in some patients, but not others, remain incompletely understood. The immune response to cancer is a complex, multistage process, and mathematical and computational models are a useful tool for understanding such complex systems. In this thesis, I develop mathematical and computational models of cytotoxic T lymphocytes (CTLs), who are key players in the immune system due to their ability to recognise, destroy, and provide long lasting protection against malignant or virally infected cells. Show less
Marijt, K.A.; Griffioen, L.; Blijleven, L.; Burg, S.H. van der; Hall, T. van 2021
Cancer cells frequently display defects in their antigen-processing pathway and thereby evade CD8 T cell immunity. We described a novel category of cancer antigens, named TEIPP, that emerge on... Show moreCancer cells frequently display defects in their antigen-processing pathway and thereby evade CD8 T cell immunity. We described a novel category of cancer antigens, named TEIPP, that emerge on cancers with functional loss of the peptide pump TAP. TEIPPs are non-mutated neoantigens despite their 'self' origin by virtue of their absence on normal tissues. Here, we describe the development of a synthetic long peptide (SLP) vaccine for the most immunogenic TEIPP antigen identified thus far, derived from the TAP-independent LRPAP1 signal sequence. LRPAP1(21-30)-specific CD8 T cells were present in blood of all tested healthy donors as well as patients with non-small cell lung adenocarcinoma. SLPs with natural flanking, however, failed to be cross-presented by monocyte-derived dendritic cells. Since the C-terminus of LRPAP1(21-30) is an unconventional and weakly binding serine (S), we investigated if replacement of this anchor would result in efficient cross-presentation. Exchange into a valine (V) resulted in higher HLA-A2 binding affinity and enhanced T cell stimulation. Importantly, CD8 T cells isolated using the V-variant were able to bind tetramers with the natural S-variant and respond to TAP-deficient cancer cells. A functional screen with an array of N-terminal and C-terminal extended SLPs pointed at the 24-mer V-SLP, elongated at the N-terminus, as most optimal vaccine candidate. This SLP was efficiently cross-presented and consistently induced a strong polyclonal LRPAP1(21-30)-specific CD8 T cells from the endogenous T cell repertoire. Thus, we designed a TEIPP SLP vaccine from the LRPAP1 signal sequence ready for validation in clinical trials. Show less
Immunotherapy approach to cancer is only benefiting to a minority of patients. In this study, we approach cancer solutions by studying the microenvironment and its immunological signature... Show moreImmunotherapy approach to cancer is only benefiting to a minority of patients. In this study, we approach cancer solutions by studying the microenvironment and its immunological signature throughout the body by focusing on the systemic immunity with new technology like mass cytometry. By highlighting specific immunological patterns in cancer, we were able to associate responsive immune cells and positive outcome, therefore paving the way to improve immunotherapy in cancer. Show less
The first part of this thesis provides insight in prognostic markers in VSCC to refine clinicopathological risk assessment. One of the most frequently described risk factors for recurrent disease... Show moreThe first part of this thesis provides insight in prognostic markers in VSCC to refine clinicopathological risk assessment. One of the most frequently described risk factors for recurrent disease is the minimal peripheral surgical margin. In order to improve the quality of future studies and clinical recommendations, we provided a practical guideline on how to uniformly measure this margin in chapter 2. We also determined the clinical relevance of the molecular classification of VSCC based on immunohistochemical staining for p16 and p53. In chapter 3 we described the immunohistochemical characterization of these molecular subtypes to aid their detection in routine clinical practice. We utilized this approach to show the difference in clinical outcome between the three distinct molecular subtypes of VSCC in chapter 4.The second part of this thesis contains studies on the tumor microenvironment as a first step towards immunotherapy for VSCC. An overview of the literature concerning immunity in VSCC at the start of our studies is provided in chapter 5. Subsequently, we interrogated the TME of different VSCC subtypes in chapter 6, and showed that high infiltration of CD4+ T cells is important for clinical outcome, irrespective of the molecular subtype of VSCC. In chapter 7 we performed an in-depth analysis on the TME based on RNA profiles and showed that highly T cell infiltrated VSCC are potentially eligible candidates for immunotherapy. In chapter 8 we exploited the expression of CD39 by CD4+ and CD8+ T cells as a marker to identify tumor specific T cells. Finally, in chapter 9 the general aspects and relevance of the studies mentioned in this thesis are combined, discussed, and placed in a broader perspective with suggestions for future research. Show less
Several immunotherapeutic strategies for the treatment of cancer are under development. Two prominent strategies are adoptive cell transfer (ACT) of CTLs and modulation of CTL function with immune... Show moreSeveral immunotherapeutic strategies for the treatment of cancer are under development. Two prominent strategies are adoptive cell transfer (ACT) of CTLs and modulation of CTL function with immune checkpoint inhibitors or with costimulatory antibodies. Despite some success with these approaches, there remains a lack of detailed and quantitative descriptions of the events following CTL transfer and the impact of immunomodulation. Here, we have applied ordinary differential equation models to two photon imaging data derived from a B16F10 murine melanoma. Models were parameterised with data from two different treatment conditions: either ACT-only, or ACT with intratumoural costimulation using a CD137 targeted antibody. Model dynamics and best fitting parameters were compared, in order to assess the mode of action of the CTLs and examine how the CD137 antibody influenced their activities. We found that the cytolytic activity of the transferred CTLs was minimal without CD137 costimulation, and that the CD137 targeted antibody did not enhance the per-capita killing ability of the transferred CTLs. Instead, the results of our modelling study suggest that an antiproliferative effect of CTLs exerted upon the tumour likely accounted for the majority of the reduction in tumour growth after CTL transfer. Moreover, we found that CD137 most likely improved tumour control via enhancement of this antiproliferative effect, as well as prolonging the period in which CTLs were inside the tumour, leading to a sustained duration of their antitumour effects following CD137 stimulation. Show less
Background: Patients with synchronous clinical stage III melanoma can present with primary melanoma lesions, locally recurrent melanoma or in-transit metastases. Neoad-juvant ipilimumab plus... Show moreBackground: Patients with synchronous clinical stage III melanoma can present with primary melanoma lesions, locally recurrent melanoma or in-transit metastases. Neoad-juvant ipilimumab plus nivolumab induces high pathologic response rates and an impressive relapse-free survival in patients with nodal macroscopic stage III melanoma. Whether primary site melanoma and in-transit metastases respond similarly to lymph node metastases with neoadjuvant immunotherapy is largely unknown. Such data would clarify whether surgical excision of these melanoma lesions should be performed before neoadjuvant therapy or whether it could be deferred and performed in conjunction with lymphadenectomy following neoadjuvant immunotherapy. Patients: Patients with synchronous clinical stage III melanoma were identified from the OpA-CIN, OpACIN-neo and PRADO neoadjuvant trials, where all patients were treated with ipi-limumab plus nivolumab. An additional case treated outside those clinical trials was included. Results: Seven patients were identified; six patients had a concordant response in primary site melanoma lesions or in-transit metastasis and the lymph node metastases. One patient had concordant progression in both the primary and nodal tumour lesions and developed stage IV disease during neoadjuvant treatment, and thus, no resection was performed. Conclusion: Pathologic response following neoadjuvant ipilimumab plus nivolumab in pri-mary site melanoma lesions or in-transit metastasis is concordant with a response in the lymph node metastases, indicating that there may be no need to perform upfront surgery to these melanoma lesions prior to neoadjuvant treatment. (c) 2021 Elsevier Ltd. All rights reserved. Show less
BackgroundTo understand how to improve the effect of immune checkpoint inhibitors in uveal melanoma (UM), we need a better understanding of the expression of PD-1 and PD-L1, their relation with the... Show moreBackgroundTo understand how to improve the effect of immune checkpoint inhibitors in uveal melanoma (UM), we need a better understanding of the expression of PD-1 and PD-L1, their relation with the presence of tumor-infiltrating lymphocytes (TILs), and their prognostic relevance in UM patients. Materials and methodsExpression of PD-1 and PD-L1 was assessed in 71 UM tissue samples by immunohistochemistry and quantitative real-time PCR (qRT-PCR), and further validated by western blotting. The effect of interferon gamma (IFN-gamma) on PD-1/PD-L1 expression was determined on four UM cell lines. ResultsImmunoreactivity of PD-1 was found in 30/71 cases and of PD-L1 in 44/71 UM samples. Tumor-infiltrating lymphocytes were found in 46% of UM tissues. PD-1 was expressed on TILs while tumor cells expressed PD-L1. UM with and without TILs showed expression of PD-1 in 69% and 18% cases, respectively (p=0.001). Similarly, PD-L1 was found in 75% of UM with TILs and in 50% of cases without TILs, respectively (p=0.03). DFS rate were lower in patients with TILs with expression of PD-1 and PD-L1, but the rate of DFS was higher with expression of PD-L1 in patients without TILs. After treatment of UM cell lines with IFN-gamma, PD-1 expression was induced in all UM cell lines whereas PD-L1 expression was found at a lower level in untreated cells, while expression also increased following treatment with IFN-gamma .ConclusionOur study suggests that increased infiltration with TILs promotes the aggressive behavior and suppresses the immune response of UM cells, thereby inhibiting immunotherapy. Show less
Tumors are complex ecosystems containing not just cancer cells, but a large variety of cell types, including immune cells. Moreover, tumors have a systemic influence: they can signal long distances... Show moreTumors are complex ecosystems containing not just cancer cells, but a large variety of cell types, including immune cells. Moreover, tumors have a systemic influence: they can signal long distances using soluble molecules and hijack non-neoplastic cells (such as immune cells) in distant organs for their own benefit, thus maximising their metastatic potential. The phenotype of immune cells in tumors and in systemic environments is therefore a key determinant of cancer progression and response to therapy.This thesis aims to understand what governs the tumor-immune ecosystem. We argue that cancer-intrinsic genetic aberrations have a dominant role in determining the tumor immune contexture, as well as systemic inflammatory activation. Understanding the intricate connection between the genetics of breast cancer and anti-tumor immune responses will help develop personalised immune intervention strategies for cancer, tailored to the genetic makeup of a patient’s tumor. Furthermore, we examine in detail the role of neutrophils in cancer-induced systemic inflammation, and how they influence the progression and spread of breast cancer. While tumors can be highly heterogeneous in nature, we show that neutrophils themselves also have a tremendous phenotypic diversity. Mapping this heterogeneity in neutrophil phenotypes may help to utilise these cells in cancer immunotherapy. Show less
Brouwer, T.P.; Vahrmeijer, A.L.; Miranda, N.F.C.C. de 2021
Background Checkpoint blockade immunotherapy has had a significant impact on the survival of a subset of patients with advanced cancers. It has been particularly effective in immunogenic cancer... Show moreBackground Checkpoint blockade immunotherapy has had a significant impact on the survival of a subset of patients with advanced cancers. It has been particularly effective in immunogenic cancer types that present large numbers of somatic mutations in their genomes. To date, all conventional immunotherapies have failed to produce significant clinical benefits for patients diagnosed with pancreatic cancer, probably due to its poor immunogenic properties, including low numbers of neoantigens and highly immune-suppressive microenvironments. Conclusions Herein, we discuss advances that have recently been made in cancer immunotherapy and the potential of this field to deliver effective treatment options for pancreatic cancer patients. Preclinical investigations, combining different types of therapies, highlight possibilities to enhance anti-tumor immunity and to generate meaningful clinical responses in pancreatic cancer patients. Results from completed and ongoing (pre)clinical trials are discussed. Show less
Dammeijer, F.; Gooijer, C.J. de; Gulijk, M. van; Lukkes, M.; Klaase, L.; Lievense, L.A.; ... ; Aerts, J.G. 2021
Background: Gemcitabine is a frequently used chemotherapeutic agent but its effects on the immune system are incompletely understood. Recently, the randomized NVALT19-trial revealed that... Show moreBackground: Gemcitabine is a frequently used chemotherapeutic agent but its effects on the immune system are incompletely understood. Recently, the randomized NVALT19-trial revealed that maintenance gemcitabine after first-line chemotherapy significantly prolonged progression-free survival (PFS) compared to best supportive care (BSC) in malignant mesothelioma. Whether these effects are paralleled by changes in circulating immune cell subsets is currently unknown. These analyses could offer improved mechanistic insights into the effects of gemcitabine on the host and guide development of effective combination therapies in mesothelioma.Methods: We stained peripheral blood mononuclear cells (PBMCs) and myeloid-derived suppressor cells (MDSCs) at baseline and 3 weeks following start of gemcitabine or BSC treatment in a subgroup of mesothelioma patients included in the NVALT19-trial. In total, 24 paired samples including both MDSCs and PBMCs were included. We performed multicolour flow-cytometry to assess co-inhibitory and-stimulatory receptor- and cytokine expression and matched these parameters with PFS and OS.Findings: Gemcitabine treatment was significantly associated with an increased NK-cell- and decreased T-regulatory cell proliferation whereas the opposite occurred in control patients. Furthermore, myeloid derived suppressor cells (MDSCs) frequencies were lower in gemcitabine-treated patients and this correlated with increased T-cell proliferation following treatment. Whereas gemcitabine variably altered co-inhibitory receptor expression, co-stimulatory molecules including ICOS, CD28 and HLA-DR were uniformly increased across CD4(+) T-helper, CD8(+) Tand NK-cells. Although preliminary in nature, the increase in NK-cell proliferation and PD-1 expression in T cells following gemcitabine treatment was associated with improved PFS and OS.Interpretation: Gemcitabine treatment was associated with widespread effects on circulating immune cells of mesothelioma patients with responding patients displaying increased NK-cell and PD-1 + T-cell proliferation. These exploratory data provide a platform for future on treatment-biomarker development and novel combination treatment strategies. (C) 2020 The Authors. Published by Elsevier B.V. Show less
Background: The treatment landscape has completely changed for advanced melanoma. We report survival outcomes and the differential impact of prognostic factors over time in daily clinical practice... Show moreBackground: The treatment landscape has completely changed for advanced melanoma. We report survival outcomes and the differential impact of prognostic factors over time in daily clinical practice.Methods: From a Dutch nationwide population-based registry, patients with advanced melanoma diagnosed from 2013 to 2017 were analysed (n = 3616). Because the proportional hazards assumption was violated, a multivariable Cox model restricted to the first 6 months and a multivariable landmark Cox model from 6 to 48 months were used to assess overall survival (OS) of cases without missing values. The 2017 cohort was excluded from this analysis because of the short follow-up time.Results: Median OS of the 2013 and 2016 cohort was 11.7 months (95% confidence interval [CI]: 10.4-13.5) and 17.7 months (95% CI: 14.9-19.8), respectively. Compared with the 2013 cohort, the 2016 cohort had superior survival in the Cox model from 0 to 6 months (hazard ratio [HR] = 0.55 [95% CI: 0.43-0.72]) and in the Cox model from 6 to 48 months (HR = 0.68 [95% CI: 0.57-0.83]). Elevated lactate dehydrogenase levels, distant metastases in >= 3 organ sites, brain and liver metastasis and Eastern Cooperative Oncology Group performance score of >= 1 had stronger association with inferior survival from 0 to 6 months than from 6 to 48 months. BRAF-mutated melanoma had superior survival in the first 6 months (HR = 0.50 [95% CI: 0.42-0.59]).Conclusion(s): Prognosis for advanced melanoma in the Netherlands has improved from 2013 to 2016. Prognostic importance of most evaluated factors was higher in the first 6 months after diagnosis. BRAF-mutated melanoma was only associated with superior survival in the first 6 months. (C) 2020 Elsevier Ltd. All rights reserved. Show less
A type I immune response is crucial for adequate tumor eradication by the immune system. However, tumors often gain evasion mechanisms that create barriers to the generation or effectiveness of a... Show moreA type I immune response is crucial for adequate tumor eradication by the immune system. However, tumors often gain evasion mechanisms that create barriers to the generation or effectiveness of a type I immune response. Among these barriers is the suppression of effective T cell priming and the inhibition of proper T cell infiltration and function in tumors. At present, the only therapies to target these barriers are focused on direct inhibition of T cell function by the tumor, through checkpoint molecules. These therapies are thus dependent on an existing type I response, and are generally not successful when tumors have insufficient T cells primed or infiltrated. This thesis has revealed ways to improve T cell priming and the infiltration of T cells in tumors. Show less
