Comparison of the expression of phosphorylated FLT3 receptor, total FLT3 receptor, and multidrug-resistant related proteins (LRP, MRP1, and MDR) among the parental MV4-11 and resistant lines. R1, R2, and R3 indicate MV4-11-R1, MV4-11-R2, and MV4-11-R3, respectively. (A) Immunoprecipitation (IP) and immunoblot analysis reveals that there is no significant difference in the expression of p-FLT3 and FLT3 receptor among MV4-11 and MV4-11-R1, -R2, and -R3. IP was performed using anti-FLT3 antibody, followed by Western blot analysis with anti–p-Tyrosine antibody. The same blot was then stripped and reprobed with anti-FLT3 antibody. (B) Western blot analysis and fluorescence-activated cell sorting (FACS) analysis found the expression of LRP, MRP1, and MDR was not varied significantly among MV4-11 and MV4-11-R1, -R2, and -R3. (C) MV4-11 and MV4-11-R cells were treated with ABT-869 at a dose of 0, 5, 10, or 20 nM for 1 hour. IP and Western blot analysis were performed the same way as described in panel A.