U87 cells were incubated for 1-[c(RGDfK)2] (A) and iRGD (B). Incubations were performed for different media conditions: with Glucose and pyruvate, without oligomycin (condition 1); with Pyruvate, without Glucose and oligomycin (condition 2); without Glucose, pyruvate and oligomycin (condition 3); with Glucose, pyruvate and oligomycin (condition 4); with pyruvate and oligomycin, without Glucose (condition 5); with oligomycin, without Glucose and pyruvate (condition 6). All the experiments were performed at least 3 times. For the E-[c(RGDfK)2] the results for all the conditions (★,,☆,,,,▾,▵) were significantly different with p<0.01. For the iRGD the results for all the conditions (▪,,□,•,,○,♦,,⋄) were significantly different with p<0.01.