MSC-AR bind to erbB2-expressing cells in vitro. A) MSC-SKOV mixed assay. MSC and MSC-AR labeled with green fluorescent dye CFDA were mixed with SKOV3ip1 cells labeled with red dye SP-DiI. After incubation in solution, cell populations were separated by FACS and percent of double-labeled population that corresponded to MSC-SKOV conglomerates was determined by gating on GFP-PE population in FACS analysis. B) MSC-K562 ELISA-based assay. K562 expressing erbB2 were obtained via lentiviral transduction. MSC or MSC-AR were cultured attached to plastic. Suspension of K562 or K562-erbB2 labeled with green fluorescent dye (CFDA) were added to cultured MSC-AR. After 1 hr incubation K562 cells were washed out and all cells in the wells were trypsinized. Cell mixture was subjected to FACS and percentage of bound fluorescent cells was determined in each well. Each group was done in triplicates.