Abstract
DNA methylation-based classification of central nervous system tumours has been increasing in importance for routine clinical workups and offers novel opportunities in discriminating ...subtypes which could lead to a more customized therapy. However, there are still unclassifiable entities for which defining an effective therapeutic regimen is challenging. The aim of our study was to gain further insight in these challenging cases. We included 81 patients with a calibrated score below 0.9 in the classifier output, who underwent surgery for a tumour of the central nervous system (CNS). 47 patients had a different output using the classifier version v11b4 when compared to their histological diagnosis. Of these, 41 patients (87.2 %) did not have any diagnosis from the methylation classifier (“no matching methylation class”). Surgical and clinicopathological features as well as DNA input had no impact on the calibrated score. Cases with non-classifiable tumors had a significantly longer time until a decision for adjuvant therapy and these cases were presented more often in neurooncological tumor boards (p< 0.01). Further analyses in 23 glioblastoma patients revealed comparable results for the overall survival, but a significantly shorter progression-free survival in cases with a discrepancy between the histological and classifier diagnosis. Application of the latest classifier version v12.5 enabled classification in 67.9% of cases, resulting in re-classification with a high calibrated score (> 0.9) in 25.7% of the tumors. Taken together, our study presents unclassifiable cases and the possible clinical impact when waiting for the accurate diagnosis in these challenging cases. Even though DNA methylation profiling significantly contributes to advanced CNS tumour diagnostics, clinicians should be aware of a prolonged interval to treatment initiation, especially for highly malignant brain tumours. Therefore, we would recommend to schedule adjuvant treatment as early as possible if surgical and histological results are suspicious for this disease.
Intratumoral heterogeneity has been identified as one of the strongest drivers of treatment resistance and tumor recurrence. Therefore, investigating the complex clonal architecture of tumors over ...time has become a major challenge in cancer research. We developed a new fluorescent “optical barcoding” technique that allows fast tracking, identification, and quantification of live cell clones in vitro and in vivo using flow cytometry (FC). We optically barcoded two cell lines derived from malignant glioma, an exemplary heterogeneous brain tumor. In agreement with mathematical combinatorics, we demonstrate that up to 41 clones can unambiguously be marked using six fluorescent proteins and a maximum of three colors per clone. We show that optical barcoding facilitates sensitive, precise, rapid, and inexpensive analysis of clonal composition kinetics of heterogeneous cell populations by FC. We further assessed the quantitative contribution of multiple clones to glioblastoma growth in vivo and we highlight the potential to recover individual viable cell clones by fluorescence-activated cell sorting. In summary, we demonstrate that optical barcoding is a powerful technique for clonal cell tracking in vitro and in vivo, rendering this approach a potent tool for studying the heterogeneity of complex tissues, in particular, cancer.
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Tracking individual tumor cell clones is technically challenging. Mohme et al. present a new lentiviral fluorescent-labeling strategy, optical barcoding, which enables fast and cost-efficient quantification of the clonal architecture of tumors as well as sorting of individual clones based on fluorescence-activated cell sorting.
Alterations in the concentration of nitric oxide (NO) and L-arginine metabolites have been associated with the pathophysiology of different vascular diseases. Here, we describe striking changes in ...L-arginine metabolism after hemorrhagic stroke. Blood and cerebrospinal fluid (CSF) samples of patients with intracerebral hemorrhage (ICH) and/or intraventricular hemorrhage were collected over a ten-day period. Liquid chromatography-tandem mass spectrometry was used to quantify key substrates and products of L-arginine metabolizing enzymes as well as asymmetric (ADMA) and symmetric dimethylarginine (SDMA). Changes in the plasma were limited to early reductions in L-ornithine, L-lysine, and L-citrulline concentrations. Intrathecally, we observed signs of early NO synthase (NOS) upregulation followed by a decrease back to baseline accompanied by a rise in the level of its endogenous NOS-inhibitor ADMA. SDMA demonstrated increased levels throughout the observation period. For arginase, a pattern of persistently elevated activity was measured and arginine:glycine amidinotransferase (AGAT) appeared to be reduced in its activity at later time points. An early reduction in CSF L-arginine concentration was an independent risk factor for poor outcome. Together, these findings further elucidate pathophysiological mechanisms after ICH potentially involved in secondary brain injury and may reveal novel therapeutic targets.
Abstract
Immune checkpoint therapy has been shown to be effective in several types of cancer, and tumor-directed immune activation is also a promising strategy in glioblastoma (GBM) patients. Our ...goal was to discover alterations in the circulating immunome of GBM patients and other cerebral tumor entities to identify soluble immune biomarkers and novel therapeutic targets. We analyzed 30 markers in plasma of 208 patients and healthy donors, using bead-based multiplex assays and flow cytometry. In a smaller cohort we further applied a high-sensitivity discovery biomarker platform with 368 markers. We included patients with 1) primary GBM (n=68), 2) recurrent GBM (n=25), 3) cerebral metastases (NSCLC, n=61; breast cancer, n=19), 4) meningioma (n=15) as well as 5) healthy donors (HD, n=20). We detected a distinct immune signature in the peripheral blood of patients with GBM, which was defined by an increased prevalence of soluble immune checkpoint markers (sCD27, sPD-L2, sGal-9), whereas soluble chemokines (CX3CL, CXCL12) were underrepresented. This signature was similar in primary and recurrent GBM, but differed markedly from other cerebral tumor entities as well as from HD. Primary GBM, but not their recurrent counterparts, additionally exhibited increased levels of neurotrophic factors (BDNF, b-NGF) and signs of immune activation with significantly increased levels of IL-18. The biomarker discovery platform further identified 76 proteins that were specifically regulated in GBM compared to HD, offering the potential to serve as biomarkers for disease activity. GBM patients with higher levels of BDNF displayed a significantly shorter survival than patients with lower levels (9.33 vs. 21.90 months; p=0.0001). Likewise patients with high concentrations of VEGF survived significantly shorter than those with low concentrations (12.97 vs. 21.90 months, p=0,0166). Taken together, we were able to delineate a specific immune profile of soluble markers in GBM patients compared to other cerebral tumor entities and to healthy individuals.
Abstract
Brain metastases are the most rapidly emerging entity in neuro-oncology. Given the decisive role of immunotherapy, the immune crosstalk between the blood circulation and the brain tumor ...requires deeper investigation, especially in light of recent data showing that T cells might be trapped in the bone marrow during the metastasis process. We analyzed the immune profile in the peripheral blood and in the bone marrow in a cohort of 40 patients with brain metastasis using flow cytometry. Our results show a global decrease in the proportion of CD3+ T cells in the peripheral blood of patients with brain metastases when compared to healthy donors (HD). CD4+ T cells were more affected by the presence of brain metastases than CD8 cells, with a significant decrease in Tregs, Th1 and Th2 helper cell populations. The proportion of naïve CD4 T cells with low expression of CXCR3 and CD127 is decreased in tumor, while a subpopulation of naïve as well as central memory CD4CM with high expression of PD1 is increased in brain metastasis patients compared to HD. Additionally, we noticed an increase in the proportion of B cells in the patient’ blood, together with a decrease in non-classical CD86+ monocytes compared to HD. The NK cell population was also affected with a significant depletion of mature NK CD57+ in the blood of patients with brain metastases. In the bone marrow, we found an increase in the proportion of senescent CD4CM CD57+ in patients with NSCLC brain metastasis, while the proportion of CD4CM CXCR3+ was significantly decreased compared to HD. Taken together, our data show that brain metastases profoundly affect the phenotype and abundance CD4+ T cells in the periphery and bone marrow, thus interfering with the primary T cell population orchestrating the tumor-specific immune response.
Abstract
Background
Malignant gliomas commandeer dense inflammatory infiltrates with glioma-associated macrophages and microglia (GAMM) promoting immune suppression, evasion, and tumor progression. ...Like all cells in the mononuclear phagocytic system, GAMM constitutively express the poliovirus receptor, CD155. Besides myeloid cells, CD155 is widely upregulated in the neoplastic compartment of malignant gliomas. Intratumor treatment with the highly attenuated rhino:poliovirus chimera, PVSRIPO, yielded long-term survival with durable radiographic responses in patients with recurrent glioblastoma (Desjardins et al. New England Journal of Medicine, 2018). This scenario raises questions about the contributions of myeloid versus neoplastic cells to polio virotherapy of malignant gliomas.
Methods
We investigated PVSRIPO immunotherapy in immunocompetent mouse brain tumor models with blinded, board-certified neuropathologist review, a range of neuropathological, immunohistochemical, and immunofluorescence analyses, and RNAseq of the tumor region.
Results
PVSRIPO treatment caused intense engagement of the GAMM infiltrate associated with substantial, but transient tumor regression. This was accompanied by marked microglia activation and proliferation in normal brain surrounding the tumor, in the ipsilateral hemisphere and extending into the contralateral hemisphere. There was no evidence for lytic infection of malignant cells. PVSRIPO-instigated microglia activation occurred against a backdrop of sustained innate antiviral inflammation, associated with induction of the Programmed Cell Death Ligand 1 (PD-L1) immune checkpoint on GAMM. Combining PVSRIPO with PD1/PD-L1 blockade led to durable remissions.
Conclusions
Our work implicates GAMM as active drivers of PVSRIPO-induced antitumor inflammation and reveals profound and widespread neuroinflammatory activation of the brain-resident myeloid compartment by PVSRIPO.
Abstract Glioblastoma is the most aggressive primary tumor of the central nervous system with a medium overall survival of 7–15 months after diagnosis. Since tumor cells penetrate the surrounding ...brain tissue, complete surgical resection is impossible and tumor recurrence is almost a certainty. New treatment modalities are therefore needed, and these should be able to trace, identify, and kill dispersed tumor cells with great accuracy. Immunological approaches in principle meet these needs. Unfortunately, due to profound tumor-associated mechanisms of immunosuppression and -evasion, immunotherapeutic strategies like peptide vaccination have so far not been translated into clinical success. If future, peptide-based vaccination approaches shall be successful in glioblastoma therapy, multiple questions need to be solved including identification of suitable antigens, route and mode of vaccination, preparation of the tumor-bearing “host” and antagonizing, as much as this is possible, glioblastoma-associated mechanisms of immune evasion and poor vaccination response. In this review we will address the immunological challenges of glioblastoma and discuss key aspects that have rendered successful immunotherapy difficult in the past.
Abstract
Cancer is a systemic disease. Due to the exceedingly rare occurrence of metastasis of cerebral glioma, systemic alterations have, however, not been considered to play a major role in disease ...progression of glioma. T cells orchestrate the adaptive immune response in an antigen-specific, cytokine mediated manner. The aim of our study was to investigate how cerebral glioma impacts systemic T cell immunobiology. We performed gene expression profiling of peripheral blood T cells in patients with IDHwt glioblastomas as well as in a murine glioma model. In addition, we analyzed the levels of soluble immune biomarkers in patient blood and performed flow-cytometric phenotyping of human peripheral blood CD3+ T cells. We discovered a significant skewing of peripheral T cell phenotypes in IDHwt glioblastoma patients compared to healthy donors (HD), showing CD4+ TH1 expansion and reduced numbers of T follicular helper cells (TFH), TH1* and mucosa associated invariant T (MAIT) cells, while TH2 and TH17 percentages remained stable. Interestingly, peripheral memory CD4+ T cells exhibited reduced Fas and PD-1 expression, while CD8 T cells were primarily affected in the non-memory CD45RA+ compartment, displaying reduced numbers of CD8+ CD127+ CD27+ cells. Compared to healthy individuals, GBM patients had significantly increased levels of soluble CD27 while levels of soluble CD25 were reduced (p < 0.05). GSEA and ORA analysis of differentially expressed genes in murine gliomas showed alterations in RNA binding and processing, as well as ribosomal activity in both cell types, indicating systemic modulation in translational- and cell cycle pathways in glioblastoma. Taken together, our results demonstrate a significant skewing of the peripheral T immunobiology in patients with IDHwt gliomas. Our data highlights the importance of considering malignant glioma as a systemic disease that fundamentally alters the immune repertoire in affected patients.
Abstract
The incidence of brain metastases (BM) in non-small cell lung cancer (NSCLC) patients is continuously increasing. The recent improvements of systemic treatment in NSCLC necessitate ...continuous updates on prognostic subgroups and factors determining overall survival. In order to improve clinical decision-making, we investigated the clinical determinants affecting survival in patients with resectable NSCLC BM. A retrospective analysis was conducted of NSCLC patients with surgically resectable BM treated in our institution between 01/2015 and 12/2020. Relevant clinical factors affecting survival identified by univariate analysis where included in a multivariate logistic regression model. Overall, 264 patients were identified, with a mean age of 62.39 ± 9.98 years at initial diagnosis of NSCLC BM and overall survival (OS) of 23.22 ± 1.71 months. Factors that significantly affected overall survival from time of primary tumor diagnosis included the systemic metastatic load (mean: 45.9 ± 9.7 vs. 58.9 ± 9.4 months, p = 0.021) as well as a number of BM < 2 (mean: 25.5 ± 4.4 vs. 57.4 ± 7.8 months, p = 0.014). When adjusted for survival time after neurosurgical intervention, a significant survival benefit was found in patients < 60 years (32.5 ± 4.3 vs. 28.5 ± 5.2 months, p = 0.036) and patients without any concurrent systemic metastases at time of NSCLC BM diagnosis (mean 32.4 vs. 34.1, p = 0.032). Our data shows that the number of BM (singular/solitary), gender and age, but not localization (infra-/supratentorial), mass-edema index or time to BM occurrence impact overall survival in NSCLC BM patients.Additionally, our study shows that patients in prognostically favorable clinical subgroups have an overall survival, which differs significantly from current statements in literature. The described clinically relevant factors may improve the understanding of the risks and the course of this disease and aid future clinical decision making in tumor boards.
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