ABSTRACT
Aim To investigate the expression of AB-CB5 and MDR1 in the cell line KG1 a and samples from acute myeloid leukemia ( AML) and their effects on multidrug resistance. Methods The expression of ABCB5 and P-gp ( the expressed product of MDR1 ) in KG1 a cells were detected by flow cytometry as well as Western blot analysis; KG1 a cells were transfected with the specific siRNA of ABCB5 using lipo2000 to reduce the expression of ABCB5; intracellular rhoda-mine123 was measured by flow cytometry;cell viability was detected by MTT; the expressions of ABCB5 and MDR1 in samples from AML were detected by real time PCR. Results ABCB5 and P-gp were overexpressed in KG1 a;the specific siRNA of ABCB5 transiently in-hibited the expression of ABCB5 in KG1 a; the siAB-CB5-KG1 a cells increased the intracellular rhodamine 123 and have been more sensitive to adriamycin com-pared with the parent KG1a. ABCB5 gene expression in samples from AML was higher than healthy people. Further, the expression of ABCB5 in 38 relapse or re-fractory AML significantly exceeded the 33 drug sensi-tive. And we found a significant positive correlation between ABCB5 expression and MDR1 gene expression in the 38 patients with relapse or refractory AML. Conclusion ABCB5 , as well as P-gp contributes to mediate multidrug resistance of AML, which provides a novel target for the therapy of relapse or refractory AML.