SOX2 and melanoma: To further explore if perturbing F-actin dynamics in the opposite direction as Jasp would alter extravasation efficiency, we treated shRNA silenced Sox2 (shSox2) TRCs (that behave like melanoma cell on rigid plastic (Supplementary Fig. 7)) with a low concentration (0.1 μM for 1 hr) of Latrunculin A (LatA), a specific drug that promotes actin depolymerization, to decrease F-actin but not to completely destroy all F-actin (Supplementary Fig. 20).