Fig. 6.

PKD1 expressing breast cancer cells show no invasive behavior and develop smaller primary tumors. a MDA-MB-231 cells stably expressing vector control or wildtype PKD1 were seeded in Matrigel 3D culture. Cell morphology was analyzed at day 20. Representative cell clusters are shown. The bars indicate 250 μm. Western blots for total PKD1 were performed using an anti-PKD1 antibody. Equal loading of the gel was controlled by staining for β-actin (anti-β-actin antibody). Experiments shown were independently performed three times with identical results. b–e MDA-MB-231 cells stably expressing vector control (labeled: Control), wildtype PKD1 (labeled: PKD1) or kinase-dead (K612W mutation) PKD1 (labeled: PKD1.KD) were orthotopically injected into the mfp of seven mice per experimental group (n = 7). At week 5 primary tumors were removed, photographed (B), and volume and weight (C) determined as described in the Materials and methods section. Asterisks indicate extreme statistical significance between Control and PKD1-expressing tumors (P = 0.0,002 for tumor volume; P<0.0,001 for tumor weight). d Immunohistological analysis. Primary tumors were fixed with formalin and either H&E stained or analyzed by IHC for expression of PKD1 and PKD1.KD using anti-PKD1 antibody. e Western blot (anti-PKD1 antibody) for ectopically expressed PKD1 after protein extraction from FFPE tumor tissue. The shifting of wildtype PKD1 (as compared to PKD1.KD) indicates activity. The animal experiments were performed twice with identical results