Research Paper Volume 8, Issue 3 pp 484—505

Figure 4. Cellular levels of miR-15b are decreased concomitant with upregulated SIRT4 gene expression in various aging models. (A) Decreased miR-15b mRNA levels in MCF7 cells following induction of senescence through TACC3 depletion (analysis on day 4 of doxycycline-induced TACC3 shRNA expression; mean ± s.d. from three independent experiments). To evaluate statistical significance, ANOVA SNK were performed (**p<0.01). (B) Analysis of miR-15b levels in MCF7 cells following ionizing radiation (application of 20 Gy at day 0; mean ± s.d. from three independent experiments). (C) Primary human dermal fibroblasts (n=4 donors) were subjected to ultraviolet irradiation (100 J/m² UVB per day) for a total of five days. Cells were harvested 24 and 72 h following the last irradiation and miR-15b levels were determined by qRT-PCR (mean ± s.d.). To evaluate statistical significance in (b) and (c), t-tests (n=3; **p<0.01) and Mann-Whitney rank sum tests (n=4; *p<0.05) were performed, respectively.