Figure 5: Effects of HO-1 inhibitor (SnPP) on cytotoxicity (a), mollugin-induced growth inhibition (b), apoptosis (c), and apoptosis-related proteins expression (d) in OSCCs. Cells were pretreated with SnPP for 3 h and treated for 3 days with mollugin (b)–(d). Cell viability was examined by MTT assay (a), and apoptosis was examined by flow cytometry (b), respectively. The same experiment was repeated in three separate cultures, and the data were presented as the means ± SD of five observations (a, b). Data are presented as mean values from triplicate determinations (c). Western data show one representative result of three independent experiments (d). *Statistically significant difference as compared to control, . #Statistically significant difference as compared to mollugin, .