Effect of ATRA on FR-β expression and f-L-calcein uptake in KG-1 cells.

Cellular FR-β expression was determined by flow cytometry using rabbit anti–FR-β (with normal rabbit IgG as an isotype control) as the primary antibody and FITC-goat anti-rabbit IgG as the secondary antibody. Liposomal uptake was determined by fluorescence of the encapsulated calcein. (A) FR-β expression in untreated KG-1 cells. (B) FR-β expression in KG-1 cells after a 5-day exposure to ATRA (1 μM). (C) Uptake of f-L-calcein and L-calcein by KG-1 cells and the effect of ATRA. Cells were treated with L-calcein without ATRA pretreatment (1), L-calcein with ATRA pretreatment(2), f-L-calcein without ATRA pretreatment (3), or f-L-calcein with ATRA pretreatment (4).