(C) Benign breast epithelial MCF10A and breast carcinoma BT-474 cells were embedded in 3D collagen as single cells or as spheroids, respectively, and the growth was followed for 5 days. Light micrographs show filamentous actin (phalloidin) and nuclei (Hoechst) in representative cell colonies. Quantitative assessment of the nuclei counts per colony show the induced proliferation in MCF10A cells after ECHCD1 sgRNA knockout. At 72 hours, MCF10A mock versus ECHDC1_sgRNA_1 and ECHDC1_sgRNA_2 P < 0.05; at 96 hours mock versus ECHDC1_sgRNA_1, ECHDC1_sgRNA_2 and ECHDC1_sgRNA_3 P < 0.001; at 120 hours mock versus ECHDC1_sgRNA_1, ECHDC1_sgRNA_2 and ECHDC1_sgRNA_3 P < 0.0001. Nuclei count relative to mock 0 hours. Error bars indicate mean ± SEM; n ≥ 10 colonies. Statistical significance was assessed with one-way ANOVA with Tukey's multiple comparison test. Scale bar 50 µm. 