Fig. 8
From: Wnt-signaling enhances neural crest migration of melanoma cells and induces an invasive phenotype
Knock-down of β-catenin with shRNA in SKMEL28 cells inhibits brain metastasis formation in the rhombencephalon of the chick embryo. a SKMEL28 aggregates were embedded into a collagen matrix with or without 3T3 or 3T3-Wnt3a stroma cells. Sprouting of SKMEL28 cells was measured at 0 h and 48 h, and an invasion index calculated as ratio of the 48 h to the 0 h value. 3T3 stroma cells, and more prominently, 3T3-Wnt3a stroma cells increased sprouting of SKMEL28 cells (**: p < 0.01; ***: p < 0.001, One way ANOVA). b Control shRNA (n = 5) or shCTNNB1 (n = 5) SKMEL28 aggregates were injected into the IVth ventricle of the stage 12/13 HH chick embryo, and analyzed after 96 h of further incubation as above. SKMEL28 control shRNA cells formed tumor nodules in the roof plate and neighboring host tissues with single infiltrating cells resembling the sprouting cells in (a). Knock-down of β-catenin via shRNA (shCTNNB1) completely blocked invasion of melanoma cells in the rhombencephalon. c BLM cells were used in the CAM metastasis assay. Pre-exposure of the BLM cells with PKF115–584 (0.5 μM for 2 h) significantly reduced liver micrometastasis but showed no effect on primary tumor formation on the CAM (Mann-Whitney test)