Extended Data Figure 7. MIDKINE enhances the ability of melanoma cells to interact with and migrate through human LEC.

a, Attachment and spreading of mCherry-labeled WM164 or SK-MEL-147 melanoma cell lines on a confluent monolayer of human LEC (HLEC) preincubated for 16 hours with 500µg/ml recombinant MDK. Statistical analysis: t-Test. (See Extended Data Videos S1 and S2 for live imaging of the spreading capacity of WM164 and SK-Mel-147 melanoma cells respectively in control vs MDK-treated HLEC cells). b, Migration of SK-Mel-147 through a confluent layer of HLEC in the absence or presence of recombinant MDK (500 µg/ml). Pictures show representative images of cells retained (up, pseudocolored in red) or transmigrating (down, green) through the HLEC layer defined by confocal videomicroscopy as described in the Methods section. c, Quantification of the percentage of migrating WM-164 or SK-MEL-147 cells in conditions as in (c). Statistical analysis: t-test. d, Histological sections of xenografts generated by SK-Mel-147 expressing control or MDK shRNA and stained for the lymphatic cell marked Lyve-1 (brown) to visualize tumor cell intravasation. e, Quantification of the number of lymphatic vessels colonized by melanoma cells in (d) per field of 25 mm² analyzed. Data correspond to mean ± SD of 3 biological replicates (with a minimum of 6 fields analyzed per tumor).