Fig. 2.

Characterisation of physical and metabolic properties of the blood–brain tumor barrier in DIPG. a Endothelial paracellular permeability to Lucifer Yellow after 24 h, 72 h and 7 days of incubation with astrocytes (control) or DIPG-007 cells. Pe = endothelial permeability coefficient. N = 3; n = 9. ns = non significant. b Representative images of tight junction protein immunostainings of zonula occludens-1 (ZO-1) and claudin-5, after 7 days of incubation. Scale bar = 25 µm. c Transcriptional expression of the genes of efflux transporters P-gp, BCRP, MRP1, MRP2, after 7 days of incubation, quantified by RT-qPCR and normalized on the expression of the housekeeping gene PPIA (cyclophilin A). *p < 0.05. N = 2; n = 6. d Protein level of efflux transporters P-gp and BCRP, after 7 days of incubation, quantified by Western blot and normalized on the protein level of β-actin. Results were obtained from two independent experiments (N = 2). ns = non significant. e P-gp and BCRP activity, evaluated by the measure of P-gp/BCRP substrate rhodamine 123 (R123) accumulation in ECs, with or without the P-gp/BCRP inhibitor elacridar, after 7 days of incubation. N = 3; n = 9