Fabian Wolpert

APO010, a synthetic hexameric CD95 ligand, induces human glioma cell death in vitro and in vivo.

Death receptor targeting has emerged as one of the promising novel approaches of cancer therapy. The activation of one such prototypic death receptor, CD95 (Fas/APO-1), has remained controversial because CD95 agonistic molecules have exhibited either too strong toxicity or too little activity. The natural CD95 ligand (CD95L) is a cytokine, which needs to trimerize to mediate a cell death signal. Mega-Fas-Ligand, now referred to as APO010, is a synthetic hexameric CD95 agonist that exhibits strong antitumor activity in various tumor models. Here, we studied the effects of APO010 in human glioma models in vitro and in vivo. Compared with a cross-linked soluble CD95L or a CD95-agonistic antibody, APO010 exhibited superior activity in glioma cell lines expressing CD95 and triggered caspase-dependent cell death. APO010 reduced glioma cell viability in synergy when combined with temozolomide. The locoregional administration of APO010 induced glioma cell death in vivo and prolonged the survival of tumor-bearing mice. A further exploration of APO010 as a novel antiglioma agent is warranted.

A disintegrin and metalloproteinases 10 and 17 modulate the immunogenicity of glioblastoma-initiating cells

BACKGROUND There are emerging reports that the family of a disintegrin and metalloproteinases (ADAM) are involved in the maintenance of the malignant phenotype of glioblastomas. Notably, ADAM proteases 10 and 17 might impair the immune recognition of glioma cells via the activating immunoreceptor NKG2D by cleavage of its ligands from the cell surface. Glioblastoma-initiating cells (GIC) with stem cell properties have been identified as an attractive target for immunotherapy. However, GIC immunogenicity seems to be low. METHODS AND RESULTS Here,we show that ADAM10 and ADAM17 are expressed on the cell surface of GIC and contribute to an immunosuppressive phenotype by cleavage of ULBP2. The cell surface expression of ULBP2 is enhanced upon blocking ADAM10 and ADAM17, and treatment with ADAM10 and ADAM17specific inhibitors leads to enhanced immunerecognition of GIC by natural killer cells. CONCLUSIONS Therefore, ADAM10 and ADAM17 constitute suitable targets to boost an immune response against GIC.

Interferon-β Modulates the Innate Immune Response against Glioblastoma Initiating Cells.

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.

The natural HLA ligandome of glioblastoma stem-like cells: antigen discovery for T cell-based immunotherapy

Glioblastoma is the most frequent malignant primary brain tumor. In a hierarchical tumor model, glioblastoma stem-like cells (GSC) play a major role in tumor initiation and maintenance as well as in therapy resistance and recurrence. Thus, targeting this cellular subset may be key to effective immunotherapy. Here, we present a mass spectrometry-based analysis of HLA-presented peptidomes of GSC and glioblastoma patient specimens. Based on the analysis of patient samples (n = 9) and GSC (n = 3), we performed comparative HLA peptidome profiling against a dataset of normal human tissues. Using this immunopeptidome-centric approach we could clearly delineate a subset of naturally presented, GSC-associated HLA ligands, which might serve as highly specific targets for T cell-based immunotherapy. In total, we identified 17 antigens represented by 41 different HLA ligands showing natural and exclusive presentation both on GSC and patient samples. Importantly, in vitro immunogenicity and antigen-specific target cell killing assays suggest these peptides to be epitopes of functional CD8+ T cell responses, thus rendering them prime candidates for antigen-specific immunotherapy of glioblastoma.

Combining standard clinical blood values for improving survival prediction in patients with newly diagnosed brain metastases-development and validation of the LabBM score.

Background We aimed to investigate the potential of standard hematologic and serum biochemical parameters to provide an independent and substantial contribution to the prediction of survival in patients with newly diagnosed brain metastases (BM). Methods Hemoglobin, white blood cell count, platelet count, serum albumin, creatinine, lactate dehydrogenase (LDH), and C-reactive protein (CRP) were assessed at diagnosis of BM in a discovery cohort of 1200 cancer patients. A multivariable Cox regression model was used to derive the LabBM score. The LabBM score was externally validated in an independent cohort consisting of 366 patients. Results Hemoglobin below lower limit of normal (ULN; HR: 1.51; P < .001), and CRP >ULN (HR: 1.52; P < .001) were associated with survival in a multivariable Cox regression model and were included in the calculation of the LabBM score. Multivariable analysis including the LabBM score and graded prognostic assessment class revealed an independent and significant association of the LabBM score with overall survival (OS) (HR: 1.42; 95% CI: 1.29-1.57; P < .001). The strong and independent association of LabBM score (HR: 1.93; 95% CI: 1.54-2.42) with OS prognosis was confirmed in the validation cohort. Conclusion Standard clinical blood parameters, combined in the easy-to-calculate LabBM score, provide strong and independent prognostic information in patients with BM. The LabBM score is an objective, inexpensive, and reproducible tool to plan clinical management strategies in BM patients and to improve patient selection and stratification for clinical trials.

Ewing’s Sarcoma as a Second Malignancy in Long-Term Survivors of Childhood Hematologic Malignancies

Modern multimodal treatment has significantly increased survival for patients affected by hematologic malignancies, especially in childhood. Following remission, however, the risk of developing a further malignancy is an important issue. The long-term estimated risk of developing a sarcoma as a secondary malignancy is increased severalfold in comparison to the general population. Ewings sarcoma family encompasses a group of highly aggressive, undifferentiated, intra- and extraosseous, mesenchymal tumors, caused by several types of translocations usually involving the EWSR1 gene. Translocation associated sarcomas, such as Ewing sarcoma, are only rarely encountered as therapy associated secondary tumors. We describe the clinical course and management of three patients from a single institution with Ewings sarcoma that followed successfully treated lymphoblastic T-cell leukemia or non-Hodgkin lymphoma. The literature on secondary Ewings sarcoma is summarized and possible pathogenic mechanisms are critically discussed.