SLAS 2019 Advanced 3D Human Models and High-Content Analysis Symposium

Introduction
Glioblastoma (GBM) is the most common and most aggressive brain tumours in adults. No cure is available and complete surgical resection is not achievable due to GBM cell infiltration into the healthy brain parenchyma. Therefore, interventions that specifically target the invasive GBM phenotype are highly desirable. However, it is challenging to model the process of GBM infiltration in real time in the laboratory in relevant model systems encompassing both tumour and neural tissue compartments. Previously we demonstrated the ability of patient derived GBM spheroids to spontaneously infiltrate mouse derived early-stage cerebral organoids (CO). Here we present an enhanced culture system enabling tractable ex vivo investigation of human GBM into human-derived CO.

Methods
Adaptation of previously described methods in murine CO has allowed us to see spontaneous infiltration of GFP-expressing GBM patient derived cell model spheroids into early stage human COs and quantified using live cell imaging and histological analysis.

Results
Patient derived GBM infiltrated in all cases CO whereas neural progenitors (NP) were unable to infiltrate. The GBM spheroid and CO self-assembly and tumour cell infiltration were characterised quantitatively using several parameters including total GBM cell infiltration, migration distance, and cell compartment spread in 3D. This ‘assembloid’ assay was also able to differentiate ‘early’ and ‘late’ invasion capabilities of GBM cell models from different patients and GBM subtypes, as well as successful infiltration of a freshly resected tumour piece.

Conclusion
We demonstrate that GBM/CO assembloids can be adapted for scalable imaging applications (for a throughput of n>100 and >10 conditions per time lapse experiment). They can be used as an ex vivo experimental model system that aims, in real-time, to recapitulate the infiltrative characteristic of GBM that makes current therapy so ineffective.

Looking forward, in collaboration with the Stem Cell Hotel (King’s College London) and industry partner Cellesce (Cardiff), we plan to automate the quantification of multiple relevant imaging parameters that may enable predictive biological readouts in the future. Furthermore, we plan to use brain tumour assembloids to establish proof-of-principle work for laboratory testing of personalised treatments as a clinical decision system that may aid treatment stratification of brain tumour patients.