Effect of FAP-α overexpression on FAK phosphorylation. (A) over-expression of FAP-α in MCF7exp cells and MDA-MB-231exp cells accompanied a decrease in phosphorylated FAK (pFAK) when cultured in both normal media and serum-free media which was restored on addition of FAKi. (B) over-expression of FAP-α in MCF7exp and MDA-MB-231exp cells had no influence on the transcription of FAK compared with those of wild type and control cells. (C) Immunofluorescence staining of FAP-α and FAK in both MCF7 and MDA-MB-231 cells showed that the over-expression of FAP-α accompanied a reduction in the fluorescence intensity of phosphorylated FAK which was partially restored using FAKi. The human breast cancer cell line BT549 was used as a positive control for endogenous FAP-α expression.