Research Paper Volume 12, Issue 21 pp 21758—21776

Caspase-3 knockout attenuates radiation-induced tumor repopulation via impairing the ATM/p53/Cox-2/PGE2 pathway in non-small cell lung cancer

Figure 5. p53 induces Cox-2 in NSCLC cells. (A) Schematic representation of the luciferase reporter plasmid with the wild-type PTGS2 promoter sequence (PTGS2-WT) or mutant sequence (PTGS2-Mut). (B) A p53-dependent stimulation of PTGS2 promoter activity was demonstrated by luciferase assay. The 293T cells were co-transfected with p53 overexpression plasmid and PTGS2-WT plasmid, PTGS2-Mut plasmid, or vector alone. The pGMR-TK reporter was used as an internal transfection standard (***p<0.001, one-way analysis of variance [ANOVA], n = 3). (C, D) Quantitative polymerase chain reaction (qPCR) and western blot analysis showed that the mRNA and protein levels of Cox-2 were elevated by overexpression of p53 in wild-type and Casp3 KO NSCLC cells. Total RNA and proteins were extracted after transfection for 24 h and 48 h, respectively (***p<0.001, Student’s t test, n = 3).