Co-culture of Glioblastoma Stem-like Cells on Patterned Neurons to Study Migration and Cellular Interactions

Summary

Here, we present an easy-to-use co-culture assay to analyze glioblastoma (GBM) migration on patterned neurons. We developed a macro in FiJi software for easy quantification of GBM cell migration on neurons, and observed that neurons modify GBM cell invasive capacity.

Abstract

Glioblastomas (GBMs), grade IV malignant gliomas, are one of the deadliest types of human cancer because of their aggressive characteristics. Despite significant advances in the genetics of these tumors, how GBM cells invade the healthy brain parenchyma is not well understood. Notably, it has been shown that GBM cells invade the peritumoral space via different routes; the main interest of this paper is the route along white matter tracts (WMTs). The interactions of tumor cells with the peritumoral nervous cell components are not well characterized. Herein, a method has been described that evaluates the impact of neurons on GBM cell invasion. This paper presents an advanced co-culture in vitro assay that mimics WMT invasion by analyzing the migration of GBM stem-like cells on neurons. The behavior of GBM cells in the presence of neurons is monitored by using an automated tracking procedure with open-source and free-access software. This method is useful for many applications, in particular, for functional and mechanistic studies as well as for analyzing the effects of pharmacological agents that can block GBM cell migration on neurons.

Introduction

Primary malignant gliomas, including GBMs, are devastating tumors, with a medium survival rate of 12 to 15 months reported for GBM patients. Current therapy relies on large tumor mass resection and chemotherapy coupled with radiotherapy, which only extends the survival rate by few months. Therapeutic failures are intimately related to poor drug delivery across the blood-brain barrier (BBB) and to invasive growth in perivascular spaces, meninges, and along WMTs¹. Perivascular invasion, also called vascular co-option, is a well-studied process, and the molecular mechanisms are beginning to be elucidated; however, the process of GBM cell invasion ....

Protocol

Informed written consent was obtained from all patients (from the Haukeland Hospital, Bergen, Norway, according to local ethics committee regulations). This protocol follows the guidelines of Bordeaux University human and animal research ethics committees. Pregnant rats were housed and treated in the animal facility of Bordeaux University. Euthanasia of an E18-timed pregnant rat was performed by using CO₂. All animal procedures have been done according to the institutional guidelines and approved by the local ethics committee. All commercial products are referenced in the Table of Materials.

1. Preparation of the p....

Results

Patterned neurons co-cultured with fluorescent GBM cells were prepared as described in the protocol section, and tracking experiments were performed. GBM cells quickly modified their shape while migrating on the neurons (Figure 1B: panel 6 and Video 1). Cells migrated along the neuronal extensions, in a random motion (Video 1). Fluorescent GBM cells and non-fluorescent neurons can be easily distinguished, and this allowed the tracking of cel.......

Discussion

Glioblastomas extensively invade the parenchyma by using different modes: co-option of surrounding blood vessels, interstitial invasion, or invasion on WMTs¹⁸. This latter mode is not well characterized in the literature because of the difficulty in finding suitable in vitro or in vivo models related to WMT invasion. Here, a simplified model has been proposed in which cultured rodent neurons were patterned on laminin-coated surfaces, and fluorescent GBM stem-like cells were seede.......

Materials

Name	Company	Catalog Number	Comments
(3-aminopropyl) triethoxysilane	Sigma	440140-100ML	The amino group is useful for the bioconjugation of mPEG-SVA
96-well round-bottom plate	Sarstedt	2582624	Used to prepare spheroids
Accutase	Gibco	A11105-01	Stored at -20 °C (long-term) or 4 °C (short-term), sphere dissociation enzyme
B27	Gibco	12587	Stored at -20 °C, defrost before use
Basic Fibroblast Growth Factor	Peprotech	100-18B	Stored at -20 °C, defrost before use
Countess Cell Counting ChamberSlides	Invitrogen	C10283	Used to cell counting
Coverslips	Marienfeld	111580	Cell culture substrate
Dessicator cartridges	Sigma	Z363456-6EA	Used to reduce mosture during (3-aminopropyl) triethoxysilane treatment
DPBS 10x	Pan Biotech	P04-53-500	Stored at 4 °C
Fiji software, MTrack2 macro	ImageJ		Used to analyze pictures
Flask 75 cm²	Falcon	10497302
HBSS	Sigma	H8264-500ML
Heparin sodium	Sigma	H3149-100KU	Stored at 4 °C
Laminin		114956-81-9	Promotes neuronal adhesion
Leonardo software			loading of envisioned micropatterns
MetaMorph Software	Molecular Devices LLC	NA	Microscopy automation software
Methylcellulose	Sigma	M0512	Diluted in NBM for a 2% final concentration
Neurobasal medium	Gibco	21103-049	Stored at 4 °C
Nikon TiE (S Fluor, 20x/0.75 NA)			inverted microscope equipped with a motorized stage
Penicillin - Streptomycin	Gibco	15140-122	Stored at 4 °C
PLPP	Alveole	PLPPclassic_1ml	Photoinitiator used to degrade the PEG brush
Poly(ethylene glycol)-Succinimidyl Valerate (mPEG-SVA)	Laysan Bio	VA-PEG-VA-5000-5g	Used as an anti-fouling coating
PRIMO	Alveole	PRIMO1	Digital micromirror device (DMD)-based UV projection apparatus
Trypan blue 0.4%	ThermoFisher	T10282	Used for cell counting
Trypsin-EDTA	Sigma	T4049-100ML	Used to detach adherent cells