Fig. 6

Dynamin 2 and Clathrin mediate the endocytosis of ABCB1-containing EV in recipient cancer cells A KB cells are transfected with siRNAs targeted against caveolin-1 and control scramble sequence RNA (s.c.). B The decrease of caveolin-1 expression in KB cells has no significant effect on the intercellular transfer of ABCB1 in co-cultures. C-D Pretreatments of KB cells with caveolae pharmacological inhibitors, methyl-β-cyclodextrin (MβCD; 1 mM)(C) and filipin III (D), show no remarkable inhibitory effects on ABCB1 transfer when compared with the untreated control cells. E The expression of clathrin is decreased by shRNA targeting clathrin as compared with control shRNA in KB cells. F The intercellular transfer rate of ABCB1 is decreased when the expression of clathrin is suppressed in KB cells. G Knockdown of dynamin2 using specific shRNA constructs is showed by immunoblot. H The suppression of dynamin-2 expression level in KB cells leads to a striking decrease in the intercellular transfer rate of ABCB1. I Pretreatment of KB cells with the inhibitor of dynamin GTPase Dynasore (10 μM) significantly reduces the rate of ABCB1 transfer, in the absence or presence of VCR. J Treatment with VCR did not alter the expression of clathrin, caveolin-1 and dynamin-2 in KB and KBv200 cells