Gerhard Jungwirth

Managing aggressive meningiomas remains challenging because of limited treatment options besides surgical tumor removal and radiotherapy. To increase the repertoire of promising therapies for aggressive meningiomas, we established a multistep drug screening workflow, focusing on targetable genes obtained from transcriptome data of highly aggressive grade 3 meningiomas. In vitro screening of 107 targeted drugs identified nine effective inhibitors. To study these drugs in a more natural environment, we established a standardized patient-derived tumor organoid (TO) model preserving accurately the original tissue’s genotype and phenotype. Individual drug responses were assessed in TOs from 60 meningioma cases characterized at the molecular level. In particular, the US Food and Drug Administration–approved epigenetic drug panobinostat demonstrated high antimeningioma efficacy in 70% of TOs, mediated through histone deacetylase 1 and 2 (HDAC1/2) inhibition. In addition, treatment in an orthotopic in vivo model revealed improved survival. In search of the molecular mechanism underlying a potentially intrinsic panobinostat resistance, we identified up-regulation of the HDAC8–transforming growth factor–β (TGFβ)–epithelial-to-mesenchymal transition (EMT) axis in the TO model, whereas subsequent HDAC8 depletion increased the sensitivity to panobinostat. These data highlight the utility of personalized drug screenings on TOs to identify suitable drug targets and inhibitors for more effective treatment of clinically aggressive meningiomas and to help advance our understanding of counteracting resistance mechanisms.

Purpose:To date, there are no systemic treatment options for patients with recurrent or refractory meningioma.Experimental Design:To identify effective drugs, we performed a large-scale drug screening using FDA-approved drugs on several meningioma cell lines. The impact of the top four compounds was assessed on cell viability, proliferation, colony formation, migration, and apoptosis. In addition, the antineoplastic effects of the selected drugs were validated in a heterotopic xenograft mouse model.Results:Analyses of the viability of meningioma cells treated with 119 antineoplastic FDA-approved drugs resulted in categorization into sensitive and resistant drug–response groups based on the mean IC50 values and peak serum concentrations (Cmax) in patients. Eighty drugs, including 15 alkylating agents, 14 antimetabolites, and 13 tyrosine kinase inhibitors, were classified as resistant (IC50 > Cmax). The sensitive drug–response group (n = 29, IC50 < Cmax) included RNA/protein synthesis inhibitors, proteasome inhibitors, topoisomerase, tyrosine-kinase, and partial histone deacetylase and microtubule inhibitors. The IC50 value of the four most effective compounds (carfilzomib, omacetaxine, ixabepilone, and romidepsin) ranged from 0.12 to 9.5 nmol/L. Most of them caused cell-cycle arrest in the G2–M-phase and induced apoptosis. Furthermore, all drugs except romidepsin significantly inhibited tumor growth in vivo. The strongest antineoplastic effect was observed for ixabepilone, which reduced tumor volume by 86%.Conclusions:In summary, a large-scale drug screening provides a comprehensive insight into the anti-meningioma activities of FDA-approved drugs, and identified carfilzomib, omacetaxine, ixabepilone, and romidepsin as novel potent antineoplastic agents for the treatment of aggressive meningiomas. The most pronounced effects were observed with ixabepilone mandating for further clinical investigation.

IDH-wildtype glioblastoma (GBM) represents the most common malignant form of brain tumor and is still incurable despite comprehensive therapeutic efforts. Due to tumor location and patient condition, open surgical resection of recurrent GBM is not always feasible. In these cases, frame-based stereotactic biopsies represent a less invasive technique to obtain tissue samples for diagnostics. However, whether this material would also be sufficient to prepare tumor organoids (TOs) and perform drug screenings has not been addressed so far. In this study, we present our highly optimized workflow for generating standardized patient-derived GBM TOs from single-cell suspensions using limited biopsy-derived material. We highlight crucial steps within the procedure, such as reliable cell counting, viable cell recovery, enzymatic digestion, and the requirement of an extracellular matrix as a scaffold. Furthermore, we showcase the potential of personalized drug testing as a promising application of GBM TOs. In conclusion, we successfully developed a robust workflow that effectively utilizes the limited material derived from stereotactic biopsies to reproducibly form standardized TOs. Moreover, we demonstrate that biopsy-derived TOs represent a valuable tool for testing drug vulnerabilities in a personalized setting, which might be especially useful in the case of non-resectable GBM.

Background: With less than 650 published cases, combination tumors of the nervous system, that is, two locally intertwined but histologically distinct tumor entities, pose a rare constellation, its clinical relevance still being a matter of debate. Methods: A consecutive cohort of 2530 patients operated on meningioma or hemangioblastoma between 2009 and 2021 was retrospectively screened for concomitant neoplastic disease to identify cases of combination tumors. Additionally, all available literature published between 1930 and 2021 was compiled in a comprehensive review. Results: Our cohort comprised 144 cases of patients with concomitant neoplastic disease and among those 10 instances of combination tumors. Another instance occurred after our screening period. Benign entities were meningiomas, but no hemangioblastoma. Contributing tumors were adenocarcinomas, lymphoma, glioblastoma, pituitary neuroendocrine tumors, and neurinoma. Patients’ age ranged from 41 to 81 years with a slight preference for females. Identification of concomitant neoplasia was first achieved due to the combination tumor in about half of our cases. For the rest, median latency until manifestation of the combination tumor was 9 years. The odds ratio for a combination tumor was 17.6 for meningioma patients with known concomitant neoplasia, but it was preoperatively suspected in 18.2% of cases only. Conclusion: Presenting one of the largest clinical series, we provide evidence that known concomitant neoplasia in patients with suspected meningioma should make clinicians consider a combination tumor. Confirmation may lead to therapeutic consequences, largely contributing to long-term prognosis. Furthermore, we present the most extensive literature review on the matter to date.

Background: Solitary fibrous tumors (SFTs)/hemangiopericytoma are rare central nervous system tumors exhibiting high recurrence rates and the ability to metastasize. This study evaluated SFT prognosis and survival outcomes, focusing on the 2021 WHO classification. Methods: A retrospective study was conducted on 49 patients who underwent SFT resection in our Neurosurgery Department between 2001 and 2023. Data were analyzed regarding sex, age, WHO grade at time of diagnosis and reclassified according to the 2021 WHO classification, tumor localization, resection grade, tumor size, adjuvant therapy, progression-free (PFS), and overall survival (OS). Kaplan-Meier survival analyses were conducted to evaluate OS and PFS, and Cox regression analyses were performed to assess prognostic factors. Results: Cohort median age was 54 (22-86) years with a female predominance of 1.22. The median follow-up was 46 (0-307) months. Primary SFTs were mainly located in the supratentorial region, followed by the infratentorial region and spine. Initially, 10% of primary tumors were graded as WHO grade 1, 49% as grade 2, and 18% as grade 3. Reclassification to WHO 2021 downgraded 65% of tumors. The five-year PFS and OS were 41.5% and 100%, respectively. In total, 41% of patients had local recurrent disease and 20% were metastatic. In univariate analyses, WHO grades, younger age (< 54 years), sex, and adjuvant radiotherapy were associated with survival. In multivariate analyses, WHO grade 3, metastatic disease, and adjuvant radiotherapy were independent PFS prognostic factors. Conclusion: Our data shows that WHO grade 3, metastatic disease, and adjuvant radiotherapy are independent PFS factors in SFTs.

Background: Tumor-associated macrophages (TAMs) represent the main immune cell population in various brain malignancies. To elucidate their biological impact in the tumor microenvironment (TME) of meningiomas (MGMs), we assessed TAM numbers, activation state, malignancy- and survival-associated changes, as well as their association with tumor-infiltrating T lymphocytes (TILs). Methods: TAM infiltration was analyzed in a multicenter cohort of 195 clinically well-annotated cases (follow-up >5 years, n =120 newly-diagnosed and n =75 recurrent MGMs) enriched for higher-grade MGMs. TAMs and M2-TAMs were quantified by tissue cytometry on whole-tumor sections. Further, we assessed levels of 27 cyto- and chemokines in a subset of tissues ( n =46 cases), and re-analyzed our previously published T cell infiltration ( n =94 cases) and expanded microarray ( n =97 cases) datasets. Results: Newly-diagnosed MGMs showed a substantial but highly heterogeneous TAM infiltration that was four times higher than for TILs. Anti-inflammatory M2-TAMs were increased in higher WHO grade tumors and in recurrent MGMs. Importantly, high M2-TAM infiltration was associated with poor progression-free survival independent of other prognostic confounders and even mitigated the beneficial prognostic effect of TIL infiltration. Additional cytokine, gene expression and pathway analyses corroborated the presence of an immunosuppressive niche in M2-TAM-enriched MGMs. Conclusions: Altogether, higher numbers of TAMs and M2-TAMs appear to be a hallmark of clinically aggressive behavior in newly-diagnosed and recurrent MGMs. Unlike TILs, immunosuppressive TAMs seem to play a dominant negative role in the immunological landscape of MGMs, highlighting M2-TAMs to be an attractive treatment target for immunotherapeutic approaches. Translational Relevance of the Study: Meningiomas (MGMs) are typically regarded as benign neoplasms, however there is a substantial proportion of clinically aggressive tumors that are refractory to standard treatment modalities and demand for the development of novel therapeutic approaches such as immunotherapy. This is the first comprehensive study reporting malignancy- and progression-associated changes of tumor-associated macrophages (TAMs), their polarization state, their association with tumor-infiltrating T lymphocytes (TILs), and their impact on patient survival in a large multicenter cohort of 195 tumors containing substantial numbers of clinically aggressive cases. Notably, we identified higher numbers of immunosuppressive M2-TAMs as an independent prognostic factor for poor survival, overriding the beneficial prognostic effects of TILs. Thus, our data highlight an important role of immunosuppressive M2-TAMs on tumor malignancy and progression, and further suggest targeting macrophages as a treatment strategy to improve the success of immunotherapeutic approaches in MGMs. Key points: Meningiomas are highly infiltrated by immunosuppressive M2-TAMs. High M2-TAM numbers are an independent negative prognostic factor for patient survival. High TAM infiltration mitigates the beneficial prognostic impact of TILs.

SUMMARY: Managing aggressive meningiomas remains challenging due to limited treatment options besides surgical tumor removal and radiotherapy. To identify novel therapies for aggressive meningiomas, we established a multi-step drug screening workflow, focusing on targetable genes obtained from transcriptome data of highly aggressive grade 3 meningiomas. In vitro screening of 107 targeted drugs identified nine effective inhibitors. To study these drugs in a more natural environment, we established a standardized patient-derived tumor organoid (TO) model preserving accurately the original tissue’s genotype and phenotype. Individual drug responses were assessed in TOs from 60 molecularly characterized meningioma cases. Especially the FDA-approved epigenetic drug panobinostat demonstrated high antimeningioma efficacy in 70% of TOs, mediated through HDAC1/2 inhibition. In addition, treatment in an orthotopic in vivo model revealed a significantly improved survival. In a heavily pretreated patient suffering from an anaplastic meningioma, oral panobinostat treatment could delay the tumor growth rate. In search of the molecular mechanism underlying a potential intrinsic panobinostat resistance, we identified upregulation of the HDAC8-TGFβ-EMT axis in the TO model and subsequent HDAC8 depletion substantially increased the sensitivity to panobinostat. These data highlight the utility of personalized drug screenings on TOs to identify suitable drug targets and inhibitors for a more effective treatment of clinically aggressive meningiomas and help to advance our understanding of counteracting resistance mechanisms. One Sentence Summary: This study provides strong in vitro , in vivo , ex vivo , and patient evidence for the efficacy of the HDACi panobinostat to treat clinically aggressive meningiomas and uncovered a potential intrinsic resistance mechanism by activation of the HDAC8-TGFβ-EMT axis.

Purpose:Targeting immunosuppressive and pro-tumorigenic glioblastoma (GBM)-associated macrophages and microglial cells (GAM) has great potential to improve patient outcomes. Colony-stimulating factor-1 receptor (CSF1R) has emerged as a promising target for reprograming anti-inflammatory M2-like GAMs. However, treatment data on patient-derived, tumor-educated GAMs and their influence on the adaptive immunity are lacking.Experimental Design:CD11b+-GAMs freshly isolated from patient tumors were treated with CSF1R-targeting drugs PLX3397, BLZ945, and GW2580. Phenotypical changes upon treatment were assessed using RNA sequencing, flow cytometry, and cytokine quantification. Functional analyses included inducible nitric oxide synthase activity, phagocytosis, transmigration, and autologous tumor cell killing assays. Antitumor effects and changes in GAM activation were confirmed in a complex patient-derived 3D tumor organoid model serving as a tumor avatar.Results:The most effective reprogramming of GAMs was observed upon GW2580 treatment, which led to the downregulation of M2-related markers, IL6, IL10, ERK1/2, and MAPK signaling pathways, while M1-like markers, gene set enrichment indicating activated MHC-II presentation, phagocytosis, and T-cell killing were substantially increased. Moreover, treatment of patient-derived GBM organoids with GW2580 confirmed successful reprogramming, resulting in impaired tumor cell proliferation. In line with its failure in clinical trials, PLX3397 was ineffective in our analysis.Conclusions:This comparative analysis of CSF1R-targeting drugs on patient-derived GAMs and human GBM avatars identified GW2580 as the most powerful inhibitor with the ability to polarize immunosuppressive GAMs to a proinflammatory phenotype, supporting antitumor T-cell responses while also exerting a direct antitumor effect. These data indicate that GW2580 could be an important pillar in future therapies for GBM.