(145d) Control On Glioblastoma Multiforme Dynamics Using Aligned Fiber Networks

Glioblastoma multiforme (GBM) is one of the most infiltrative and aggressive forms of brain cancer with an estimated life expectancy of just over one year after diagnosis.  Contributing to grim prognosis is the high migration speed of GBM cells such as DBTRG’s (Denver Brain Tumor Research Group).  These cells, which attach to and interact with their immediate fibrous microenvironment known as the extracellular matrix (ECM), receive region-specific biochemical and biophysical cues from their underlying substrates.  The ability to manipulate cell motion and perhaps increase the migration rates of these cells may contribute to an enhanced survivability of GBM by providing drug therapies a “worst-case scenario” testing platform.  Here we present DBTRG cell behavior on the STEP (Spinneret-based Tunable Engineered Parameters) platform, which deposits high aspect ratio nano/micro fibers with tight control on diameter, spacing, porosity, and orientation.  The resulting fibrous scaffolds, which mimic the mechanistic environment of ECM by providing biomechanical cues, can be tuned to alter migration speed for therapeutics applications.

In this study, DBTRG cells are seeded onto fibrous STEP scaffolds and their migration speeds are shown to directly result from varying substrate stiffness in forms of fiber lengths of 4, 8 and 16mm.  Fibrous scaffolds were spun using the previously-reported STEP technique.  Polystyrene fibers 500 nm in diameter were spun onto two substrate types (suspended single-layer (SS) and suspended double-layer (SD)) in addition to flat glass control.  Using standard cell culture techniques, DBTRGs were seeded onto the scaffolds and attached within 4-6 hours.  After attaching, 2 mL media was added to keep cells viable over a 24 hour period.  During this time, cells on fiber networks were time-lapse imaged by an incubating microscope.  Cell migration speeds were calculated by tracking the position of the cell’s nucleus every hour and noting the maximum distance traveled per hour in a 16-hour window. 

Cells were observed to attach to and elongate along the fiber axis.  Cells constricted to SS fibers wrapped themselves entirely around the fiber, and traveled at speeds of 35 μm/hr on the 4mm substrates.  As the length of the fiber was increased, the substrate stiffness decreased and focal adhesions become temporally less stable, leading to an increased migration speed.  For example, DBTRG’s traveled at approximately 60 μm/hr on the 8mm substrates and over 80 μm/hr on the 16mm substrates.  STEP platform provides a unique tool to fine-tune the mechanical environment to which native cells attach and interact with so that scaffolds and drug delivery therapies may be improved upon in the future.