Biology subjects

Wilhelm, M. T.

Publications and source records attributed to Wilhelm, M. T..

3 recordsLinked to original sources

bioRxiv2024

Ephrin-A2 and Phosphoantigen-Mediated Selective Killing of Medulloblastoma by γδT Cells Preserves Neuronal and Stem Cell Integrity

Medulloblastoma (MB) is a pediatric brain tumor that develops in the cerebellum, representing one of the most common malignant brain cancers in children. Standard treatment includes surgery, chemotherapy, and radiation, but despite a 5-year survival rate of approximately 70%, these therapies often lead to significant neurological damage in the developing brain. This underscores the urgent need for less toxic, more effective therapeutic alternatives. Recent advancements in cancer immunotherapy, including immune checkpoint inhibitors and CAR-T cell therapy, have revolutionized cancer treatment. One promising avenue is the use of Gamma Delta ({gamma}{delta})T cells, a unique T cell population with potential advantages such as non-alloreactivity, potent tumor cell lysis, and broad antigen recognition. However, their capacity to recognize and target MB cells remains underexplored. To investigate the therapeutic potential of {gamma}{delta}T cells against MB, we analyzed the proportion and status of MB-infiltrated {gamma}{delta}T cells within patient datasets. We next investigated the expression of {gamma}{delta}T cell ligands on MB cells and identified EphA2 receptor and the phosphoantigen/Butyrophilin complex as key ligands, activating V{gamma}9V{delta}1 and V{gamma}9V{delta}2 T cells, respectively, leading to significant MB cell lysis in both monolayer and spheroid models. Importantly, preliminary safety data showed that {gamma}{delta}T cells did not target differentiated neurons or neuroepithelial stem cells derived from induced pluripotent stem cells, underscoring the selectivity and safety of this approach. In conclusion, {gamma}{delta}T cells trigger an efficient and specific killing of MB, and would offer a promising novel therapeutic strategy. Key messagesMedulloblastoma patients often experience significant long-term side effects from current standard treatments. Immunotherapy has emerged as a promising alternative to conventional therapeutic approaches. In our study, we demonstrated that {gamma}{delta}T cells can efficiently and specifically target medulloblastoma cells without causing harm to healthy neuronal tissue. These findings suggest that {gamma}{delta} T cell therapy may provide therapeutic benefits while potentially reducing treatment-related toxicity in medulloblastoma patients.

cancer biology↗

bioRxiv2024

Development of an orthotopic medulloblastoma zebrafish model for rapid drug testing.

Medulloblastoma (MB) is one of the most common malignant brain tumors in children. Current preclinical in vivo model systems for MB have increased our understanding of molecular mechanisms regulating MB development; however, they may not be suitable for high-throughput screening efforts. We demonstrate here that transplantation of seven different MB cell lines or patient-derived cells into the blastula stage of zebrafish embryos leads to orthotopic tumor cell growth that can be observed within 24 hours after transplantation. Importantly, the homing of transplanted cells to the hindbrain region and the aggressiveness of tumor growth are enhanced by pre-culturing cells in a neural stem cell-like medium. The change in culture conditions rewires the transcriptome towards a more migratory and neuronal progenitor phenotype, including the expression of guidance molecules SEMA3A and EFNB1, both of which correlate with lower overall survival in MB patients. Furthermore, we highlight that the orthotopic zebrafish MB xenograft model has the potential to be used for high-throughput drug screening. Key pointsO_LIMedulloblastoma cells home to the hindbrain region in developing zebrafish embryos. C_LIO_LINeural stem cell culture conditions improve the homing capacity of MB tumor cells. C_LIO_LIMedulloblastoma-transplanted zebrafish embryos can be used as a high-throughput in vivo model for drug screening. C_LI Importance of the StudyOne of the challenges of accurately modeling medulloblastoma is the large heterogeneity in tumor characteristics. To accurately model this heterogeneous disease, patient-derived xenograft mouse models are currently the standard. However, such mouse models are labor intensive, time-consuming, and not suitable for high-throughput studies. Here, we describe a quick and straightforward zebrafish xenograft model that provides a promising alternative to these existing mouse models. We demonstrate that this model can be utilized to study tumor cell growth of several major medulloblastoma subgroups. More importantly, our model facilitates high-throughput drug testing, providing a scalable opportunity for in vivo drug screenings that will support the discovery of novel therapeutic compounds against medulloblastoma.

cancer biology↗

bioRxiv2024

High-throughput neural stem cell-based drug screening identifies S6K1 inhibition as a selective vulnerability in SHH-medulloblastoma

BackgroundMedulloblastoma (MB) is one of the most common malignant brain tumors in children. Current treatments have increased overall survival but can lead to devastating side effects and late complications in survivors, emphasizing the need for new, improved targeted therapies that specifically eliminate tumor cells while sparing the normally developing brain. MethodsHere, we used a SHH-MB model based on a patient-derived neuroepithelial stem (NES) cell system for an unbiased high-throughput screen with a library of 172 compounds with known targets. Compounds were evaluated in both healthy neural stem cells and tumor cells derived from the same patient. Based on the difference of cell viability and drug sensitivity score between normal cells and tumor cells, hit compounds were selected and further validated in vitro and in vivo. ResultsWe identified PF4708671 (S6K1 inhibitor) as a potential agent that selectively targets Sonic Hedgehog (SHH) driven MB tumor cells while sparing neural stem cells and differentiated neurons. Subsequent validation studies confirmed that PF4708671 inhibited the growth of SHH-MB tumor cells both in vitro and in vivo, and that knockdown of S6K1 resulted in reduced tumor formation. ConclusionOverall, our results suggest that inhibition of S6K1 specifically affects tumor growth, whereas it has less effect on non-tumor cells. Our data also show that the NES cell platform can be used to identify potentially effective new therapies and targets for SHH-MB. Key pointsO_LIHigh-throughput screening system using the NES model identifies efficient compounds and targets against SHH-MB. C_LIO_LIS6K1 inhibition shows selectivity toward tumor cells while having less effect on normal neural stem cells and neurons. C_LI Importance of the studyCurrent treatment modalities for medulloblastoma have improved overall survival but also come with detrimental side effects for survivors. Therefore, novel treatment options need to be developed which will specifically target the tumor cells while sparing the healthy brain. In this study, we tested a library of compounds targeting commonly dysregulated oncogenic pathways on both normal neural stem cells and SHH-MB tumor cells derived from the same patients. Interestingly, we found that most compounds including commonly used targeted therapy such as PI3K or mTOR inhibition, albeit effective, affected tumor cells and normal cells similarly. However, inhibition of the downstream effector S6K1 preferentially targeted tumor cells both in vitro and in vivo. These results thus reveal potential targets for translational studies of novel therapies that specifically target medulloblastoma tumor cells.

cancer biology↗