Grgdsp

Human U-87 and U-251 glioblastoma cells were obtained from ATCC (Manassas, VA, USA); Dulbecco’s modified Eagle medium (DMEM), from Mediatech (Manassas, VA, USA); fetal bovine serum (FBS) and penicillin–streptomycin, from Invitrogen (Carlsbad, CA, USA); poly-L-lysine solution (0.01%), from Sigma Aldrich (Saint Louis, MO, USA); sodium pyruvate, MEM non-essential amino acids, and GlutaMax, from Life Technologies (Carlsbad, CA, USA); and trypsin, from CellGro (Manassas, VA, USA). A WST cell proliferation assay kit was purchased from Dojindo Molecular Technologies (Rockville, MD, USA). High-viscosity alginic acid sodium salt from brown algae (alginate) was purchased from Sigma Aldrich (Saint Louis, MO, USA); sterile alginate covalently coupled with GRGDSP, from FMC BioPolymer (Philadelphia, PA, USA); rat-tail collagen, from Advanced BioMatrix (San Diego, CA, USA); and agarose (low melting), from Thermo Fisher Scientific (Waltham, MA, USA), used as received. The chemical inhibitor of the RhoA-ROCK pathway (Y-27632) was purchased from Selleck Chemicals (Houston, TX, USA), and that of the Rac pathway (NSC23766), from EMD Biosciences (La Jolla, CA, USA). Integrin inhibitor RGD was purchased from Selleck Chemicals (Houston, TX, USA); GRGDSP, from Sigma Aldrich (Saint Louis, MO, USA); and cilengitide, from MedChem Express (Monmouth Junction, NJ, USA).

Solutions of Laminin (LN, 20 μg mL^–1; Sigma–Aldrich) and of the peptide glycine–arginine–glycine-aspartic acid–serine–proline (GRGDSP, 50 μg mL^–1; Sigma–Aldrich) were prepared in phosphate-buffered saline (PBS; Life Technologies, Waltham, MA, United States). Protein or peptide crosslinking to the amine group, previously introduced in the PCL fibers by aminolysis, was performed by reaction over 24 h in glutaraldehyde atmosphere (Migneault et al., 2004 (link)), using a solution of 2.5% vol/vol glutaraldehyde (GA; Sigma–Aldrich). Afterward, the samples were washed with PBS five times and immersed in a solution of glycine (100 mg mL^–1 in PBS; Sigma–Aldrich) for 1 h at room temperature, to quench free aldehyde groups. Finally, the samples were washed again five times with PBS at room temperature.

Unless otherwise stated, all chemicals and plastics were from Sigma (St. Louis, MO, USA). Recombinant proteins were from R&D Systems (Abingdon, UK). The neutralizing antibodies, UK-356618 and BC 11 hydrobromide were from R&D Systems (the antibody against TSP-1 was from Abcam (Cambridge, UK)). GRGDSP was from Sigma and SB202190 from Cell Signaling Technology (Danvers, MA, USA).