Fig. 4
Inhibiting the PDGFRβ-STAT5 axis induces apoptosis. A Representative pictures of cleaved caspase 3 (CC3) IHC analysis of (n = 19) fl/fl Pdgfrb and (n = 20) Δ/Δ Pdgfrb mouse thymomas at the experimental end point. Black squares in the left pictures represent the area chosen for the magnification depicted on the right. Scale bars: 50 μm. Whole-slide scans were quantified using Definiens™ software (right graph). B Representative pictures of Bcl-xL IHC analysis of (n = 18) fl/fl Pdgfrb and (n = 11) Δ/Δ Pdgfrb mouse thymomas at the experimental end point. Black squares in the left pictures represent the area chosen for the magnification depicted on the right. Scale bars: 50 μm. Whole-slide scans were quantified using Definiens™ software (right graph). C PDGFRβ expression levels were divided into either high (n = 7; grey) or low (n = 13; orange) and correlated to Bcl-xL IHC of patient primary tumor samples. D BCL2, MCL1, BCL2L1 (Bcl-xL) gene expression comparison between (n = 6) ALCL patients and healthy donors of the Piccaluga dataset [32] extrapolated from the Oncomine database [34]. Heatmap colors represent z-scores normalized to depict relative values within rows, where blue represents least expressed and red represents most expressed. E Normalized ChIP-seq alignment track for STAT3 and STAT5 (unstimulated or stimulated with either IL-2, or IL-21) in murine CD4+ T cells compared to IgG, shown at the gene loci for Bcl2l1 (Bcl-xL). Read densities (y-axis) were normalized to reads per million reads sequenced in each sample. F Representative FACS plots of fl/fl Pdgfrb and Δ/Δ Pdgfrb murine primary tumor cells co-stained with 7-aminoactinomycin D (7AAD) and Annexin V. The right graph indicates the percentage of necrotic, living, early or late apoptotic cells in both genotypes as indicated. G Western blot showing protein levels of CC3 and PDGFRβ in a fl/fl Pdgfrb primary tumor cell line following AC-4-130 treatment. GAPDH serves as the loading control. The molecular weight of analyzed proteins in kiloDaltons (KDa) is shown on the left. A, B, C, D and E Data are shown as means ± SD, and p values were 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)