Fig 2: Up-regulation of E-cadherin expression by rhIL-15 on RPTEC is dependent of the ßc-dependent signaling pathway.The ?c neutralization, as well as JAK3 or STAT5 inhibition, hamper the maintenance of E-cadherin surface expression induced by rhIL-15 on RPTEC without interfering on the E-cadherin down-regulation on rhIL-15-treated RCC7. Cells were pretreated with 1 µg/ml of neutralizing anti-IL2R? antibody mAb2842, 0.25 µM of JAK3 inhibitor (CP-690, 550, Calbiochem) or 100 µM of STAT5 inhibitor (STAT5 Inh., 573108, Calbiochem) for 1 h before adding the recombinant cytokine (10 pg/mL) for 5 days. Treatment with rhIL-15 and STAT5 inhibitor was renewed at day 3. White histograms refer to isotype-matched control. Mean fluorescence intensity values for each marker are shown in each histogram. The data are representative of 3 separate experiments performed using different RCC (RCC5, RCC8) and RPTEC batches.

Fig 3: Reestablishment of IL-2R? chain-dependent signal transduction pathway in RCC interferes with the rhIL-15-induced E-cadherin down-regulation.RCC7 were transiently transfected for 48 hours with vectors containing IL-2R? and/or JAK3 Human cDNA. A) Transient expression of IL-2R? and JAK3 was analyzed by immunoblotting in each transfected RCC. Immunoblotting for ß-actin was used as a control for equal protein loading and transfer. B) Flow cytometry shows that 40 min rhIL-15 treatment did not induce STAT5 phosphorylation in IL-2R?- or JAK3-transfected RCC while rhIL-15 treatment induced STAT5 phosphorylation in co-transfected cells. C) After 48 h, transfected RCC were treated for an additional 48 h with 10 pg/mL of rhIL-15 before evaluating E-cadherin expression by flow cytometry. The introduction of either IL-2R? chain, JAK3 or both molecules do not modify E-cadherin expression on untreated rhIL-15 cells, while the E-cadherin down-regulation observed after 48 hours of rhIL-15 treatment was counterbalanced only in co-transfected cells. Mean fluorescence intensity values for each marker are shown in each histogram. One experiment representative of a total of three is shown.