FIGURE 6 from Integrin-αvβ3 is a Therapeutically Targetable Fundamental Factor in Medulloblastoma Tumorigenicity and Radioresistance

Radioresistant medulloblastomas overexpress integrin-αvβ3 and are sensitive to cilengitide. A, A heat map showing integrin gene expression in naïve versus radioresistant DAOY and HD-MB03 cells. Integrin expression was quantified by qRT-PCR. Results are expressed compared with normal cerebellum (log₁₀-fold change). The means of three independent experiments are presented. B, Representative western blots of β3-integrin protein expression in naïve versus radioresistant DAOY (top) and HD-MB03 (bottom) cells. Three independent experiments were performed. The proliferation of naïve versus radioresistant DAOY (C) and HD-MB03 (D) cells treated with cilengitide (2.5 µmol/L) for 96 hours. Proliferation rates are expressed as the percentage of day 0. Three independent experiments were performed, and data are presented as mean ± SEM. Key: **, P < 0.01; ***, P < 0.001. Invasion assays of naïve versus radioresistant DAOY (E) and HD-MB03 (F) cells treated with cilengitide for 12 and 24 hours, respectively. Serum-starved cells were treated with cilengitide (2.5 µmol/L) and allowed to invade for 12 (DAOY) or 24 hours (HD-MB03). Invasions were conducted using Boyden chambers coated with Matrigel, and the results are expressed as the percentage of control naïve cells. Three independent experiments were performed, and data are presented as mean ± SEM. Key: **, P < 0.01; ***, P < 0.001 versus untreated cells; ^#, P < 0.05; ^##, P < 0.01 versus naïve cells. Effect of cilengitide on PARP cleavage. Naïve or radioresistant DAOY (G) and HD-MB03 (H) cells were treated with cilengitide (20 µmol/L) for 48 hours. Cell lysates were analyzed by Western blot analysis with an anti-PARP antibody. Three independent experiments were performed, with representative blots shown.