Patupilone inhibits IR-induced MMP activity and cell invasion in human U251 glioma cells. A , clonogenic cell survival of U251 cells was determined after treatment with patupilone and IR, similar to the experiments performed with the HT1080 cells, n = 3. B, MMP activity was measured in the CM derived from U251 cells treated with 0.05 nM patupilone and indicated doses of IR, n = 6. C, cell invasion was assessed using a Transwell invasion assay, after treatment with 0.05 nM of patupilone and 2 Gy of IR, n > 3. **P < 0.01, ***P < 0.001. MMP activity and cell invasion assays were performed similar to the experiments with the HT1080 cells.