Twist1 induction induced rapid and robust epithelial cell dissemination. Representative DIC time-lapse movies of CMV::rtTA;TRE-Twist1 organoids isolated from the same mouse cultured in 3D Matrigel in basal medium. Without Twist1 induction (no doxycycline, left), the epithelium maintained a smooth basal surface with the ECM (corresponds to Fig. 5 B). With Twist1 induction (5 µg/ml doxycyline, right), single cells rapidly disseminated into the ECM with extensive protrusions (corresponds to Fig. 5 C). Videos start 2 h after doxycyline addition. Frames were collected every 20 min for 161 h (displayed at 24 frames/s) using a Cell Observer system with an AxioObserver Z1 and an AxioCam MRM camera (Carl Zeiss). Bars, 50 µm.
