Fig. 3: Human colon cancer-derived mesenchymal stem cells promote the generation of cancer stem cells and enhance angiogenesis in vitro.

a SW48 cells treated with CC-MSC-CM were assayed for clonogenicity in adherent cultures. Separated clones were counted and plotted. b Effect of CC-MSC-CM on serial sphere-formation assays of SW620. Tumor spheres were generated in suspension culture for 2 weeks using Ultra-Low Attachment plates (magnification, ×100; scale bar: 250 μm). *P < 0.05 compared with mock treatment. c Human umbilical vein endothelial cells (HUVECs) were cultivated in CM from control SW48 cells and SW48 cells pretreated with CC-MSC-CM for 24 h. The cells’ tube formation ability was quantified by counting the branching points per field (magnification, ×100; scale bar: 250 μm). ***P < 0.001. d ELISA was used to examine the VEGFA level in the CM obtained in Fig. 3c. All experiments were carried out in triplicate. *P < 0.05