Establishment of a Doxorubicin-Resistant Subline from flcute Myeloid Leukemia (ell Line

Introduction: in order to determine the multidrug resistance (mdr)phenotype due to p-glycoprotein expression in haematologicalmalignancies including acute myeloblastic leukemia (aml), a wellcharacterizedp-gp expressing cell line was required to validate andstandardize flow cytometric assays and to calibrate instruments.therefore, this resistant subline of k562 was established for the firsttime in iran in order to study the mdr phenotype due to p-gpexpression in some cancers.material and methods: a resistant subline of k562 (kdi/20) todoxorubicin from the same parental k562 was derived by stepwiseincreasing the concentration of doxorubicin up to 20 ng/ml as a goldstandard. for flow cytometric assessment of p-gp expression, 4e3anti-p-gp was used. the resistant cell line was studied by rhodamine123 for functional assay of p-gp. mdr1 gene expression was alsoconfirmed using rt-pcr.results: p-glycoprotein was expressed in final concentration of 20ng/ml of doxorubicin on 70% of k562 cells after 120 passages. therhodamine 123 influx was 37%. the over-expression of mdr1 genewas observed in a 30-cycle pcr.conclusion: p-glycoprotein is expressed in human k562 cell line(k562) by continuous exposure to anticancer drug. p-glycoproteinexpression is detected by several methods including flow cytometryand rt-pcr, and the number of pcr cycles is very important