Viability assays after modulation of microRNA expression in proliferating keratinocytes. A. Proliferating keratinocytes were transfected with pre-miRNA for miR-191-5p or miR-200b-3p or miR-331-3p (pre-miR-specific) or with a Pre-miR negative control. MiRNA relative expression was assessed 48 h after transfection by RT-QPCR (bilateral paired t-test: *p≤0.05, **p≤0.01, ***p≤0.001). B. The relative 6Gy/0Gy viability (reported to the pre-miR negative control transfection) is indicated for each individual or combined (pool) pre-miR transfection at 24 h, 48 h and 72 h post-irradiation (n=4 ; error bars show SD ; bilateral paired t-test : *p≤0.05, ***p≤0.001).