Advancements in 3D-engineered scaffolds to capture core and edge features of glioblastoma

Abstract

Glioblastoma is one of the deadliest types of brain cancer with patients having a poor prognosis. The development of effective treatments requires physiologically relevant disease model systems. Although there are a variety of 3D glioblastoma culture models available, they fail to capture a key characteristic, namely core and edge tumour regions. The tumour core refers to the central region of the tumour distinguished by densely packed quiescent cells. The edge is located at the periphery of the tumour, where infiltrating/proliferating tumour cells interact with normal tissue. In this study, we successfully designed and fabricated a two-photon polymerized 3D printed scaffold and developed a microinjection-based protocol for guiding the growth of biomechanically constrained glioblastoma spheroids. The formation of the spheroid was achieved by injecting nL-volumes of cells on the scaffolds either functionalized with an extracellular matrix (ECM) coating or embedded in Collagen hydrogel. An alignment protocol based on the use of fiducial cross-shaped markers was employed to align the microinjector needle to the desired position. The culture model was tested by examining cell colonization with a commercial glioblastoma cell line (U87) as well as with patient-derived glioblastoma cells. Immunofluorescence (IF) staining and scanning electron microscopy (SEM) were employed to characterize the model. Two core and two edge-specific immunofluorescence markers were tested to analyse the core and edge formation further. IF and SEM imaging revealed a dense core and protruding edge-like cells both in the ECM-coated scaffold and the collagen-embedded ones. Further, we observed a remarkable difference in terms of F-actin expression between the core and edge region. We compared these results with those obtained in a scaffold-free model, which showed that the presence of the scaffold influences the behaviour of glioblastoma cells, resulting in guided growth, along the microfabricated structures. The developed 3D culture model paves the way for further investigation of core and edge dynamics as well as for prospective in-vitro drug screening.