CDC25A-Q110del Novel Isoform Role in Lung Cancer Figure 3. CDC25AQ110del confers more CDC25A protein stability and promotes cellular survival under UV radiation. A. Time course cyclohexamide (50 ug/ml) treatment of H1299 cells transfected with pEGFPN1-CDC25Awt or pEGFPN1-CDC25AQdel under unperturbed conditions showed increased half-life of CDC25AQ110 (,15 minutes) versus CDC25Awt. B. UV radiation followed by 30 minutes incubation of 293F cells in 37uC, CDC25AQ110del showed more stability compared to CDC25Awt. C. 293F cells plated at equal cell density and transfected with equal amount of EGFP labeled CDC25AQ110del or CDC25Awt. After 72 hrs of transfection, flowcytometry analysis gating equal number of EGFP expressing cells for each isoform. Histogram shows intensity of expression of CDC25AQ110del-EGFP (mean 59.2) versus CDC25Awt-EGFP (mean 40.5) (t-test P = .05). D. The same population of cells gated for EGFP-CDC25A expression was studied for cell cycle distribution. The CDC25Awt-EGFP showed to arrest in the post G2 phase (.G2/M) compared to control (p = 0.055). The EGFP-CDC25AQ110del expressing cells showed less accumulation of hyperploid cell population at the .G2/M phase and accelerated the cells more through mitosis compared to the EGFP-CDC25Awt expressing cells (p = 0.0047). E. Cell viability assay of H1299 expressing CDC25Awt versus CDC25AQ110del after 24 hr of several doses of UV radiation. CDC25AQ110del expression rescued H1299 sensitivity to UV radiation in relation to the control group. doi:10.1371/journal.pone.0046464.g003 PLOS ONE | www.plosone.org 7 October 2012 | Volume 7 | Issue 10 | e46464