Figure 1From: Possible role of membrane gamma-glutamyltransferase activity in the facilitation of transferrin-dependent and -independent iron uptake by cancer cells.Effects of modulation of membrane GGT activity on transferrin-mediated uptake of 55Fe by 4 human cancer cell lines expressing different levels of GGT activity. Data shown are means ± SEM of 2–5 experiments. Panel A: U937 histiocytoma cells (*significantly different from control value, P < 0.05; **significantly different from the "+GSH+gly-gly" value, P < 0.05). Panel B: Me665/2/60 melanoma cells (*significantly different from control value, P < 0.05). Panel C: K562 erythroleukemia cells (**significantly different from the "+GSH+gly-gly" value, P < 0.05). Panel D: Me665/2/21 melanoma cells (differences not statistically significant).Back to article page