BMP4 antagonist Gremlin and MMP inhibitor Batimastat reverse the stellate phenotype of MDA-MB-231 cell clusters in Matrigel. The cells received 1 μg/ml Gremlin, 10 μM Batimastat and/or 100 ng/ml BMP4. Vehicle-treated cells were used as a control. Images were taken as indicated in Figure 2 and representative examples from day 14 are shown. Scale bar 200 μm.