FAK signaling in CAFs is required for their promotion of tumor cell migration. A. Immuno-blots showing levels of SMA, FAK-pY397, FAK and Actin in WI-38 human fibroblasts that are not treated (NT) or treated with conditioned media from respective human breast cancer cells. B. Quantification of respective protein levels normalized against total FAK in WI-38 fibroblasts described in A. C. Illustration of co-culture trans-well migration assay. D. Quantification of migrated cells in trans-well migration assays of human breast cancer cells that were educated by fibroblasts (not treated [NT] or treated with respective conditioned media from tumor cells). E. Immuno-blots showing levels of FAK, SMA and GAPDH in WI-38 cells treated with shCtrl or shFAK to knockdown FAK. F. Quantification of trans-well migration assays of MDA-MB-231 tumor cells to WI-38 cells treated with shFAK and/or MDA-231 conditioned medium for 72 hours. Levels of FAK knockdown in WI-38 cells are indicated by immune-blots. G-H. Representative images (G) and quantification (H) of migrated cells in trans-well migration assays of PyMT tumor cells to primary fibroblasts purified from lungs of WT, Ctrl or cKO mice. Scale bar, 50μm. Error bars indicate mean ±SEM. *p<0.05, **P<0.01.