A 3D Topographical Model of Parenchymal Infiltration and Perivascular Invasion in Glioblastoma

Abstract

Glioblastoma (GBM) is the most common and invasive primary brain cancer. GBM tumors are characterized by diffuse infiltration, with tumor cells invading slowly through the hyaluronic acid (HA)-rich parenchyma toward vascular beds and then migrating rapidly along microvasculature. Progress in understanding local infiltration, vascular homing, and perivascular invasion is limited by an absence of culture models that recapitulate these hallmark processes. Here we introduce a platform for GBM invasion consisting of a tumor-like cell reservoir and a parallel open channel "vessel" embedded in 3D HA-RGD matrix. We show that this simple paradigm is sufficient to capture multi-step invasion and transitions in cell morphology and speed reminiscent of those seen in GBM. Specifically, seeded tumor cells grow into multicellular masses that expand and invade the surrounding HA-RGD matrices while extending long (10-100 µm), thin protrusions resembling those observed for GBM in vivo. Upon encountering the channel, cells orient along the channel wall, adopt a 2D-like morphology, and migrate rapidly along the channel. Structured illumination microscopy reveals distinct cytoskeletal architectures for cells invading through the HA matrix versus those migrating along the vascular channel. Substitution of collagen I in place of HA-RGD supports the same sequence of events but with faster local invasion and a more mesenchymal morphology. These results indicate that topographical effects are generalizable across matrix formulations, but that mechanisms underlying invasion are matrix-dependent. We anticipate that our reductionist paradigm should speed the development of mechanistic hypotheses that could be tested in more complex tumor models.

A mode of cell adhesion and migration facilitated by CD44-dependent microtentacles

“…1G). We have previously demonstrated that U-87 MG cells invade HA-RGD by tunneling into the bulk matrix over the course of several weeks and that invasion is preceded by elaboration of long protrusions (37). We observe here that U-251 MG tumorspheres cultured in HA for 10 d exhibit protrusions into the matrix and initial tunneling (SI Appendix, Fig.…”

Dissecting and rebuilding the glioblastoma microenvironment with engineered materials

“…119,120 The contributions of the perivascular niche to therapy resistance, infiltration spread and disease progression are perhaps best understood. 83,118,[122][123][124] In the perivascular niche, GSCs and the TME engage in cooperative signalling, promoting neovascularization and GSC maintenance. The leaky vasculature provides access to nutrients, and the endothelium activates Notch-dependent pathways that promote GSC self-renewal and therapy resistance.…”

“…Interestingly, dimensionality alone can profoundly affect cell responses to chemotherapeutics, independent of matrix stiffness or composition. 181 Materials used for 2D substrates, such as collagen 181,[186][187][188][189][190] and HA 123,183 , can also be employed as 3D scaffolds. However, materials such as polyacrylamide or polycaprolactone (PCL) requiring harsh solvents or crosslinking reagents during gelation cannot be easily seeded with cells unless they are made highly porous such that cells can be incorporated into the matrix after gelation.…”

Three‐dimensional biomimetic hyaluronic acid hydrogels to investigate glioblastoma stem cell behaviors

“…We also studied the impact of RGD incorporated in HA hydrogels as RGD is the key integrin‐binding sequence in fibronectin, which is enriched in the ECM of GBM tumors when compared to normal brain tissue (Kim & Kumar, ). Previously, RGD has been associated with increased adhesion and invasion of GBM cells in matrix‐free TCPS as well as 3D HA matrix (Paolillo, Serra, & Schinelli, ; Wolf, Lee, & Kumar, ; Xiao et al, ). In our system, apart from serum grown U87 cells, we observed no significant difference in the cell expansion, proliferation, and sphere sizes of serum‐free grown cells when incorporated in HA‐RGD hydrogels as compared with HA only hydrogels.…”