Aligned chitosan-polycaprolactone polyblend nanofibers promote the migration of glioblastoma cells

摘要

In vitro models that accurately mimic the microenvironment of invading glioblastoma multiform (GBM) cells will provide a high-throughput system for testing potential anti-invasion therapies. Here, we investigate the ability of chitosan-polycaprolactone polyblend nanofibers to promote a migratory phenotype in human GBM cells by altering the nanotopography of the nanofiber membranes. Fibers were prepared with diameters of 200 nm, 400 nm, and 1.1 µm, and were either randomly oriented or aligned to produce six distinct nanotopographies. Human U-87 MG GBM cells, a model cell line commonly used for invasion assays, were cultured on the various nanofibrous substrates. Cells showed elongation and alignment along the orientation of aligned fibers as early as 24 hrs and up to 120 hrs of culture. After 24 hrs of culture, human GBM cells cultured on aligned 200 nm and 400 nm fibers showed marked upregulation of invasion-related genes including β-catenin, Snail, STAT3, TGF-β, and Twist, suggesting a mesenchymal change in these invading cells. After 120 hrs, there was only a slight upregulation of these genes in human GBM cells cultured on 400 nm and 1.1 µm aligned and random fibers, indicating slower, less pronounced transformation. The decrease in expression of these genes from 24 hrs to 120 hrs on 200 nm and 400 nm aligned fibers was attributed to asymmetric cell division, a hallmark of mesenchymal-like cells. Therefore, small (200 and 400 nm) diameter aligned nanofibers induce the greatest degree of phenotype change indicative of cell invasion behavior in human GBM. Additionally, cells cultured on 400 nm aligned fibers showed similar migration profiles as those reported in vivo, and thus these nanofibers should provide a unique high-throughput in vitro culture substrate for developing anti-invasion therapies for the treatment of GBM.