Fig. 3

PDGFRβ activates STAT5. A Western blot showing protein levels of PDGFRβ, phospho (p) STAT3, total STAT3, phospho (p) STAT5 and total STAT5 in thymomas excised from (n = 4) fl/fl Pdgfrb and (n = 4) Δ/Δ Pdgfrb mice at the experimental end point. GAPDH serves as the loading control. The molecular weight of analyzed proteins in kiloDaltons (KDa) is shown on the left. B Western blot showing protein levels of PDGFRβ, phospho (p) NPM-ALK, total NPM-ALK, phospho (p) STAT5, total STAT5, phospho (p) STAT3 and total STAT3 in HEK293FT transfected cell lysates. GAPDH serves as the loading control. The molecular weight of analyzed proteins in kiloDaltons (KDa) is shown on the left. C Western blot showing phosphotyrosine-100 (pTyr-100) levels following a kinase assay with PDGFRβ and STAT5 recombinant (r) proteins. The kinase assay was performed in the absence (−) or presence (+) of ATP and 5 μM of Imatinib. The highlighted bands indicate phospho (p) PDGFRβ and (p) STAT5. Total STAT5 serves as the loading control. D Western blot showing protein levels of PDGFRβ, phospho (p) STAT5 and total STAT5 in two fl/fl Pdgfrb primary tumor cell lines subjected to CRISPR/Cas9 mediated deletion of Pdgfrb. GAPDH serves as the loading control. The molecular weight of analyzed proteins in kiloDaltons (KDa) is shown on the left. E Representative pictures of PDGFRβ, phospho-STAT5 and total STAT5 IHC analysis and grading scheme to quantify staining of tissue microarrays from human ALCL tumor samples. F PDGFRβ expression levels were divided into either high (n = 7; grey) or low (n = 13; orange) and correlated to total STAT5 as detected by IHC. G Correlation between phospho (p) STAT5 and total PDGFRβ IHC scores of ALCL tissue specimens (n = 16). Pearson correlation, p = 0.03 and DFn = 1.14. F data is shown as the mean ± SD, and the p value was determined by the unpaired two-tailed Student’s t-test (ns = p > 0.05; * = p < 0.05; ** = p < 0.01; *** = p < 0.001; **** = p < 0.0001)