Inhibition of gene expression in UV-challenged HaCaT human keratinocytes. Gene expression was measured by qPCR analyses of IL-1β (A), IL-6 (B), and IL-8 (C) at 6 h, after a 3 min UV challenge and in the presence of 50 μg/mL algal extracts. EA and ET, apices and thallus 50%-ethanol extracts; DA and DT, apices and thallus DMSO extracts, respectively. Data are normalized on the HPRT-1 housekeeping gene and expressed as mRNA-fold increase compared to control cells. Asterisks indicate significance in Tukey test (IL-1β ANOVA p < 0.000001, Tukey of respective bar vs. UV, * p < 0.0005 and ** p < 0.0001, respectively; IL-6 ANOVA p < 0.000001, Tukey of respective bar vs. UV, ** p < 0.0005; IL-8 ANOVA p < 0.000001, Tukey of respective bar vs. UV, * p < 0.05 and ** p < 0.005).