Cell death assessment after 72 h. Comparative FACS analysis following T + C treatment versus control in SK-MEL-28 and BJ fibroblasts co-culture cells; quantitative FACS results for BJ + SK-MEL-28 are expressed as % of total cell count-annexin V and PI positive cells, from the total cell number (a); viable cells (b) as well as early and late apoptosis (c) were statistically analyzed. Cell death induced by celecoxib group was not significant. Celecoxib used alone did not alter cell viability, while celecoxib added to trametinib enhanced apoptosis mediated cell death in the last group compared to control and trametinib group. ** p < 0.01, **** p < 0.0001 vs. control, untreated cells and *** p < 0.001, **** p < 0.0001 vs. trametinib group. Each bar represents mean ± standard deviation (n = 3).