Figure 2.

Influence of p21 knockdown on the thiamine/ThDP-induced changes in the levels of glutathione (A–D), glutathione disulfide (E–H), their ratio (I–L), p53 protein level (M–P) and NAD(P)H:XTT reductase activity (Q–T) of A549^wt and A549^p21- cells. The cells were cultured in DMEM prepared with 4 mg/L thiamine hydrochloride (Control, A, B, E, F, I, J, M, N, Q, R) or without thiamine (Thiamine deficiency, C, D, G, H, K, L, O, P, S, T). After 24 h, the media were exchanged for those without (gray columns) or with 5 mM ThDP (black columns), and the indicated parameters were assayed as described in Materials and Methods. The data of at least three independent experiments are presented as means ±SEM. On the graphs, only the statistically significant differences of the ThDP effects are indicated by p-values above the horizontal lines connecting the compared groups. Statistical significances of the differences between all the groups are shown in Table 1. GSH—glutathione, GSSG—glutathione disulfide.