Fig. 1.

Analyses of the sensitivity to NVP-AEW541 and IGF-1 receptor siRNA and the characterization of IGF-1 receptor status. (A) Sensitivity of cultures to NVP-AEW541 treatment. Sensitivity was analyzed by comparing growth in tissue culture media containing 10% FCS, with and without the addition of 3 µM of NVP-AEW541; 100% growth inhibition corresponds to a situation with equal number of cells at the start and the end of the experiment. Results are means derived from 2 to 3 experiments for each cell culture. (B) Apoptotic and proliferative effects of NVP-AEW541 on 2 sensitive glioma cultures. (C and D) Efficacy of downregulation of IGF-1 receptor mRNA and protein levels upon IGF-1 receptor siRNA treatment. mRNA levels were determined after 3 days of siRNA treatment by qRT-PCR, and the receptor levels were determined in WGA fractions by IGF-1 receptor immunoblotting. Quantification of the receptor levels, normalized to β-actin levels, is shown as bar diagram above immunoblotting images. (E) IGF-1 receptor downregulation reduces the growth rate of cultures 35 and 4. Effects of IGF-1 receptor downregulation on growth were analyzed following 3 days of culture in 1% FCS. (B, C, and E) Results are means of 3 experiments for each cell culture and error bars indicate the standard deviation. The significance of changes was determined by Student's t-test. (F) IGF-1 receptor expression and phosphorylation in glioblastoma cultures. β-Actin amounts indicate input amount of the different cell lysates.