Despite improvement of therapeutic treatments for breast cancer, the development of brain metastases has become a major limitation to life expectancy for many patients. Brain metastases show very ...commonly alterations in EGFR and HER2 driven pathways, of which PTEN is an important regulator. Here, we analyzed PTEN expression in 111 tissue samples of breast cancer brain metastases (BCBM). Loss of PTEN was found in a substantial proportion of BCBM samples (48.6%) and was significantly associated with triple-negative breast cancer (67.5%, p = 0.001) and a shorter survival time after surgical resection of brain metastases (p = 0.048). Overexpression of PTEN in brain-seeking MDA-MB-231 BR cells in vitro reduced activation of the AKT pathway, notably by suppression of Akt1 kinase activity. Furthermore, the migration of MDA-MB-231 BR cells in vitro was promoted by co-culturing with both astrocytes and microglial cells. Interestingly, when PTEN was overexpressed the migration was significantly inhibited. Moreover, in an ex vivo organotypic brain slice model, PTEN overexpression reduced invasion of tumor cells. This was accompanied by reduced astrocyte activation that was mediated by autocrine and paracrine activation of GM-CSF/ CSF2RA and AKT/ PTEN pathways. In conclusion, loss of PTEN is frequently detected in triple-negative BCBM patients and associated with poor prognosis. The findings of our functional studies suggest that PTEN loss promotes a feedback loop between tumor cells and glial cells, which might contribute to disease progression.
Peripheral metastases of glioblastoma (GBM) are very rare despite the ability of GBM cells to pass through the blood-brain barrier and be disseminated through the peripheral blood. Here, we describe ...a detailed genetic and immunological characterization of a GBM metastasis in the skeleton, which occurred during anti-PD-1 immune checkpoint therapy. We performed whole genome sequencing (WGS) and 850 K methylation profiling of the primary and recurrent intracranial GBM as well as one of the bone metastases. Copy number alterations (CNA) and mutational profiles were compared to known genomic alterations in the TCGA data base. In addition, immunophenotyping of the peripheral blood was performed. The patient who was primarily diagnosed with IDH-wildtype GBM. After the resection of the first recurrence, progressive intracranial re-growth was again detected, and chemotherapy was replaced by PD-1 checkpoint inhibition, which led to a complete intracranial remission. Two months later MR-imaging revealed multiple osseous lesions. Biopsy confirmed the GBM origin of the skeleton metastases. Immunophenotyping reflected the effective activation of a peripheral T-cell response, with, however, increase of regulatory T cells during disease progression. WGS sequencing demonstrated distinct genomic alterations of the GBM metastasis, with gains along chromosomes 3 and 9 and losses along chromosome 4, 10, and 11. Mutational analysis showed mutations in potentially immunologically relevant regions. Additionally, we correlated tumour-infiltrating lymphocyte and microglia presence to the occurrence of circulating tumour cells (CTCs) in a larger cohort and found a decreased infiltration of cytotoxic T cells in patients positive for CTCs. This study exemplifies that the tumour microenvironment may dictate the response to immune checkpoint therapy. In addition, our study highlights the fact that despite an effective control of intracranial GBM, certain tumour clones have the ability to evade the tumour-specific T-cell response and cause progression even outside of the CNS.
Glioblastoma is the most common primary brain cancer in adults and represents one of the worst cancer diagnoses for patients. Suffering from a poor prognosis and limited treatment options, tumor ...recurrences are virtually inevitable. Additionally, treatment resistance is very common for this disease and worsens the prognosis. These and other factors are hypothesized to be largely due to the fact that glioblastoma cells are known to be able to obtain stem-like traits, thereby driving these phenotypes. Recently, we have shown that the in vitro and ex vivo treatment of glioblastoma stem-like cells with the hormonally active form of vitamin D3, calcitriol (1α,25(OH)2-vitamin D3) can block stemness in a subset of cell lines and reduce tumor growth. Here, we expanded our cell panel to over 40 different cultures and can show that, while half of the tested cell lines are sensitive, a quarter can be classified as high responders. Using genetic and proteomic analysis, we further determined that treatment success can be partially explained by specific polymorphism of the vitamin D3 receptor and that high responders display a proteome suggestive of blockade of stemness, as well as migratory potential.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The immunological composition of the tumor microenvironment has a decisive influence on the biological course of cancer and is therefore of profound clinical relevance. In this study, we analyzed the ...cooperative effects of integrin β4 (ITGB4) on tumor cells and E-/P-selectin on endothelial cells within the tumor stroma for regulating tumor growth by shaping the local and systemic immune environment.
We used several preclinical mouse models for different solid human cancer types (xenograft and syngeneic) to explore the role of ITGB4 (shRNA-mediated knockdown in tumor cells) and E-/P-selectins (knockout in mice) for tumor growth; effects on apoptosis, proliferation and intratumoral signaling pathways were determined by histological and biochemical methods and 3D in vitro experiments; changes in the intratumoral and systemic immune cell composition were determined by flow cytometry and immunohistochemistry; chemokine levels and their attracting potential were measured by ELISA and 3D invasion assays.
We observed a very robust synergism between ITGB4 and E-/P-selectin for the regulation of tumor growth, accompanied by an increased recruitment of CD11b
Gr-1
cells with low granularity (i.e., myeloid-derived suppressor cells, MDSCs) specifically into ITGB4-depleted tumors. ITGB4-depleted tumors undergo apoptosis and actively attract MDSCs, well-known to promote tumor growth in several cancers, via increased secretion of different chemokines. MDSC trafficking into tumors crucially depends on E-/P-selectin expression. Analyses of clinical samples confirmed an inverse relationship between ITGB4 expression in tumors and number of tumor-infiltrating leukocytes.
These findings suggest a distinct vulnerability of ITGB4
tumors for MDSC-directed immunotherapies.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Objectives
Infection with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) causes coronavirus disease 2019 (COVID‐19). Although an acute SARS‐CoV‐2 infection mainly presents with ...respiratory illness, neurologic symptoms and sequelae are increasingly recognised in the long‐term treatment of COVID‐19 patients. The pathophysiology and the neuropathogenesis behind neurologic complications of COVID‐19 remain poorly understood, but mounting evidence points to endothelial dysfunction either directly caused by viral infection or indirectly by inflammatory cytokines, followed by a local immune response that may include virus‐specific T cells. However, the type and role of central nervous system‐infiltrating T cells in COVID‐19 are complex and not fully understood.
Methods
We analysed distinct anatomical brain regions of patients who had deceased as a result of COVID‐19‐associated pneumonia or complications thereof and performed T cell receptor Vβ repertoire sequencing. Clonotypes were analysed for SARS‐CoV‐2 association using public TCR repertoire data.
Results
Our descriptive study demonstrates that SARS‐CoV‐2‐associated T cells are found in almost all brain areas of patients with fatal COVID‐19 courses. The olfactory bulb, medulla and cerebellum were brain regions showing the most SARS‐CoV‐2 specific sequence patterns. Neuropathological workup demonstrated primary CD8+ T‐cell infiltration with a perivascular infiltration pattern.
Conclusion
Future research is needed to better define the relationship between T‐cell infiltration and neurological symptoms and its long‐term impact on patients' cognitive and mental health.
In COVID‐19 patients, neurological symptoms and complications are increasingly recognised, but their underlying causes remain poorly understood. This study found that SARS‐CoV‐2‐associated T cells were present in various brain regions of patients who had fatal COVID‐19 pneumonia, with the olfactory bulb, medulla and cerebellum showing the most specific patterns. These T cells primarily consisted of CD8+ T cells and were localised around blood vessels. Further research is required to fully understand the connection between T‐cell infiltration in the brain and its impact on patients' cognitive and mental health in the long term.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Circulating tumor DNA (ctDNA) has shown great promise as a minimally invasive liquid biopsy for personalized cancer diagnostics especially among metastatic patients. Here, we used a novel sensitive ...assay to detect clinically relevant mutations in ctDNA in blood plasma from metastatic non-small cell lung cancer (NSCLC) patients, including patients with a limited oligo-brain metastatic disease. We analyzed 66 plasma samples from 56 metastatic NSCLC patients for 74 hotspot mutations in five genes commonly mutated in NSCLC using a novel MassARRAY-based lung cancer panel with a turnaround time of only 3 days. Mutations in plasma DNA could be detected in 28 out of 56 patients (50.0%), with a variant allele frequency (VAF) ranging between 0.1% and 5.0%. Mutations were detected in 50.0% of patients with oligo-brain metastatic disease, although the median VAF was lower (0.4%) compared to multi-brain metastatic patients (0.9%) and patients with extra-cranial metastatic progression (1.2%). We observed an overall concordance of 86.4% (
= 38/44) for
status between plasma and tissue. The MassARRAY technology can detect clinically relevant mutations in plasma DNA from metastatic NSCLC patients including patients with limited, oligo-brain metastatic disease.
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Immunotherapy targeting glioblastoma initiating cells (GIC) is considered a promising strategy. However, GIC are prone to evade immune response and there is a need for potent adjuvants. IFN-β might ...enhance the immune response and here we define its net effect on the innate immunogenicity of GIC. The transcriptomes of GIC treated with IFN-β and controls were assessed by microarray-based expression profiling for altered expression of immune regulatory genes. Several genes involved in adaptive and innate immune responses were regulated by IFN-β. We validated these results using reverse transcription (RT)-PCR and flow cytometry for corresponding protein levels. The up-regulation of the NK cell inhibitory molecules HLA-E and MHC class I was balanced by immune stimulating effects including the up-regulation of nectin-2. In 3 out of 5 GIC lines tested we found a net immune stimulating effect of IFN-β in cytotoxicity assays using NKL cells as effectors. IFN-β therefore warrants further investigation as an adjuvant for immunotherapy targeting GIC.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Immune cell infiltration varies widely between different glioblastomas (GBMs). The underlying mechanism, however, remains unknown. Here we show that TGF-beta regulates proliferation, migration, and ...tumorigenicity of mesenchymal GBM cancer stem cells (CSCs) in vivo and in vitro. In contrast, proneural GBM CSCs resisted TGF-beta due to TGFR2 deficiency. In vivo, a substantially increased infiltration of immune cells was observed in mesenchymal GBMs, while immune infiltrates were rare in proneural GBMs. On a functional level, proneural CSC lines caused a significantly stronger TGF-beta-dependent suppression of NKG2D expression on CD8(+) T and NK cells in vitro providing a mechanistic explanation for the reduced immune infiltration of proneural GBMs. Thus, the molecular subtype of CSCs TGF-beta-dependently contributes to the degree of immune infiltration.
Purpose: Major shortcomings of traditional mouse models based on xenografted human glioblastoma cell lines are that tumor cells do
not invade and that genetic alterations, such as amplification of ...the epidermal growth factor receptor ( EGFR ) gene, are not maintained. Such models are thus of limited value for preclinical studies. We established a highly invasive
model to evaluate the effect of antibodies against EGFR (cetuximab) and vascular endothelial growth factor receptor-2 (antibody
DC101).
Experimental Design: After short-term culture, glioblastoma spheroids were implanted into the brains of nude mice. Animals were treated either
i.c. with cetuximab or i.p. with DC101. Tumor burden was determined histologically using image analysis of 36 different landmark
points on serial brain sections.
Results: Invasive xenografts were obtained from nine different glioblastomas. Three of seven cases treated with cetuximab responded
with significant tumor growth inhibition, whereas four did not. All responsive tumors were derived from glioblastomas exhibiting
EGFR amplification and expression of the truncated EGFRvIII variant, which were maintained in the xenografts. All nonresponsive
tumors lacked EGFR amplification and EGFRvIII expression. The proportion of apoptotic cells was increased, whereas proliferation and invasion
were decreased in responsive tumors. None of four xenograft cases treated with DC101 responded to treatment, and the diffusely
invading tumors grew independent of angiogenesis.
Conclusions: Inhibition of glioblastoma growth and invasion can be achieved using i.c. delivery of an anti-EGFR antibody, but tumor response
depends on the presence of amplified and/or mutated EGFR. Antiangiogenic treatment with DC101 is not effective against diffusely
invading tumors.
The receptor for epidermal growth factor (EGFR) is a prime target for cancer therapy across a broad variety of tumor types. As it is a tyrosine kinase, small molecule tyrosine kinase inhibitors ...(TKIs) targeting signal transduction, as well as monoclonal antibodies against the EGFR, have been investigated as anti-tumor agents. However, despite the long-known enigmatic EGFR gene amplification and protein overexpression in glioblastoma, the most aggressive intrinsic human brain tumor, the potential of EGFR as a target for this tumor type has been unfulfilled. This review analyses the attempts to use TKIs and monoclonal antibodies against glioblastoma, with special consideration given to immunological approaches, the use of EGFR as a docking molecule for conjugates with toxins, T-cells, oncolytic viruses, exosomes and nanoparticles. Drug delivery issues associated with therapies for intracerebral diseases, with specific emphasis on convection enhanced delivery, are also discussed.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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