Research Paper Volume 8, Issue 8 pp 1608—1624

Figure 5. The pro-tumourigenic SASP of human senescent oral fibroblasts depends on elevated secretion of PGE2. qRT-PCR showed increased expression of COX-2 mRNA in senescent oral fibroblasts compared to proliferating controls (n=3) (A). Senescent oral fibroblasts secreted more PGE2 than proliferating control (n=3) (B). Treatment of senescent and control oral fibroblasts with celecoxib, a selective COX-2 inhibitor, diminished PGE2 secretion (n=3) (C). Blockade of COX-2 activity in both senescent and proliferating control oral fibroblasts dramatically attenuated the migration of H357 cells towards fibroblast derived conditioned medium (n=3) (D). Celecoxib treated fibroblasts secreted less IL-6 into the conditioned media (both senescent and proliferating) (n=3) (E). qRT-PCR and western blot showed COX-2 inhibition in senescent fibroblasts is associated with declined transcript levels of SASP associated miRNAs: miR-335 (F) (n=2) and increased expression of PTEN protein (G), respectively (n=4). All experiments were performed independently as indicated by n and with technical repeats. The bars represent mean ± STDEV (A, F) or mean ± SEM. *p<0.05, by paired student's t-test (G), one-way ANOVA with post-hoc correction by Dunn's method (A) and Holm-Sidak method (B) and two-way ANOVA for determining functional activity of COX-2 with post-hoc correction by Holm-Sidak method (C) and Bonferroni t-test (D-E). (See Supplementary Figure S5 and Supplementary Table S1).