TIP-1 and Radioresistance of Malignant Gliomas Figure 3. TIP-1 protein levels correlate to the radiation-induced apoptosis in D54 cells. A) Caspase-3 cleavage within D54 cells were examined with western blot. Cells received mock (untreated) or 5 Gy IR treatment were analyzed 24 hours post the treatment. The blots were scanned using a densitometer to quantify the proteins of interest. Relative fold change of caspase-3 activation for each cell line was normalized to the respective vector control (counted as 1). B) Flow cytometric analyses of Annexin V/PI stained cells. Cells were analyzed at the indicated time points post the mock or 10 Gy IR treatment. Shown are mean +/2 standard deviation of at least three independent experiments performed in triplicate. Significance was determined by comparing the denoted group to the respective vector control with the same treatment, respectively. * p,0.05 with t-test. doi:10.1371/journal.pone.0045402.g003 PLOS ONE | www.plosone.org 6 September 2012 | Volume 7 | Issue 9 | e45402