FIGURE 6 from Identification of MUC1-C as a Target for Suppressing Progression of Head and Neck Squamous Cell Carcinomas

MUC1-C regulates NOTCH3 expression and HNSCC cell self-renewal capacity. A, CAL27/tet-MUC1shRNA cells treated with vehicle or DOX for 7 days were analyzed for NOTCH3 mRNA levels. The results (mean ± SD of four determinations) are expressed as relative levels compared with that obtained for vehicle-treated cells (assigned a value of 1; left). Lysates were immunoblotted with antibodies against the indicated proteins (right). B, GSEA of RNA-seq data from CAL27/tet-MUC1shRNA cells treated with vehicle or DOX for 7 days using the REACTOME SIGNALING BY NOTCH3 gene signature. C, The indicated CAL27 cells treated with vehicle or DOX for 7 days were analyzed for tumorsphere formation. Shown are representative images of the tumorspheres (bar represents 100 µm). SFE is expressed as the mean ± SD of three independent replicates relative to that obtained for vehicle-treated cells (assigned a value of 1). D, Lysates from CAL27 cells treated with vehicle or 5 µmol/L GO-203 for 3 days were immunoblotted with antibodies against the indicated proteins. E, CAL27 cells were treated with vehicle or 5 µmol/L GO-203 while they were analyzed for colony formation. Shown are representative photomicrographs of stained colonies (left). The results (mean ± SD of three determinations) are expressed as relative colony formation compared with that for vehicle-treated cells (assigned a value of 1; right). F, CAL27 cells were treated with vehicle or 5 µmol/L GO-203 while they were analyzed for tumorsphere formation. Shown are representative images of the tumorspheres (bar represents 100 µm). SFE is expressed as the mean ± SD of three independent replicates relative to that obtained for untreated cells (assigned a value of 1). G and H, Six-week-old nude mice were injected subcutaneously in the flank with 1 × 10⁷ CAL27 cells. Mice pair-matched into groups of 5 mice each when tumors reached 100–150 mm³ were treated with vehicle control or GO-203 for the indicated days. Tumor volumes are expressed as the mean ± SEM for 5 mice (G). Lysates from control and GO-203–treated tumors were immunoblotted with antibodies against the indicated proteins (H).