HO-1 overexpression leads to decreases in heme and globin levels and increases ferritin and eIF2α-P protein levels in MEL cells after their differentiation. MEL cells were stably transfected with HO-1 and incubated with DMSO for 72 hours. (A) After DMSO-induced differentiation, MELHO-1 cells exhibited a lower degree of redness than control cells. (B) After 72 hours of incubation with DMSO, MEL cells were harvested and washed, and their heme content was measured. (C) Representative western blot showing TfR, ferritin, and globin protein levels after 48 hours of incubation with DMSO; these cells were treated with and without SnPP (an inhibitor of HO activity). A vertical line has been inserted to indicate a repositioned gel lane. (D) Densitometric analysis of TfR, ferritin, and globin protein levels normalized to β-actin. *^,**Statistical significance when compared with control cells without SnPP. †Statistical significance when compared with MELHO-1 cells without SnPP. (E) Representative western blot showing eIF2α-P protein levels in control and MELHO-1 cells after 48 hours of incubation with DMSO. (F) Densitometric analysis of eIF2α-P protein levels normalized to eIF2α-total and β-actin. Error bars of graphs represent standard deviation of 3 independent experiments (n = 3). *^,†P < .05; **P < .001.