Multidrug resistance protein attenuates gemtuzumab ozogamicin–induced cytotoxicity in acute myeloid leukemia cells

Blood ◽  
2003 ◽  
Vol 102 (4) ◽  
pp. 1466-1473 ◽  
Author(s):  
Roland B. Walter ◽  
Brian W. Raden ◽  
Tom C. Hong ◽  
David A. Flowers ◽  
Irwin D. Bernstein ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Multidrug Resistance ◽  
Myeloid Leukemia ◽  
Resistance Mechanisms ◽  
Gemtuzumab Ozogamicin ◽  
Multidrug Resistance Protein ◽  
Acute Myeloid Leukemia Cells ◽  
Additional Resistance ◽  
Resistance Protein ◽  
Acute Myeloid

Abstract Gemtuzumab ozogamicin (GO) is a novel immunoconjugate therapy for acute myeloid leukemia (AML). P-glycoprotein (Pgp) confers resistance to GO and is associated with a worse clinical response. To address whether multidrug resistance protein (MRP) affects GO susceptibility, we characterized Pgp, MRP1, and MRP2 expression in CD33+ cell lines and CD33+ AML samples and analyzed the effect of the Pgp inhibitor cyclosporine (CSA) and the MRP inhibitor MK-571 on GO-induced cytotoxicity. MRP1, but not MRP2, expression correlated with MRP activity. MK-571 enhanced GO-induced cytotoxicity in Pgpnegative/MRP-positive NB4 and HL-60 cells. CSA, but not MK-571 alone, restored GO susceptibility in Pgp-positive/MRP-positive TF1 cells; however, MK-571 enhanced cytotoxicity in the presence of CSA. All patient samples exhibited MRP activity, and 17 of 23 exhibited Pgp activity. CSA increased GO-induced cytotoxicity in 12 Pgp-positive samples, whereas MK-571 alone was effective in only one sample with minimal Pgp activity. In 3 Pgp-positive/MRP-positive samples, MK-571 enhanced GO-induced cytotoxicity in the presence of CSA. Thus, MRP1 may attenuate susceptibility to GO. This effect was comparatively less than that for Pgp and required the inhibition of Pgp for detection in cells that coexpressed both transporters. Because MK-571 and CSA failed to affect cytotoxicity in a portion of Pgp-positive/MRP-positive AML samples, additional resistance mechanisms are likely important.

Deletion of the multidrug resistance protein MRP1 gene in acute myeloid leukemia: the impact on MRP activity

Blood ◽  
2000 ◽  
Vol 95 (11) ◽  
pp. 3514-3519 ◽  
Author(s):  
Dorina M. van der Kolk ◽  
Edo Vellenga ◽  
Anneke Y. van der Veen ◽  
Leonore Noordhoek ◽  
Hetty Timmer-Bosscha ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Multidrug Resistance ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Multidrug Resistance Protein ◽  
Normal Bone Marrow ◽  
Normal Bone ◽  
Resistance Protein ◽  
Acute Myeloid

Abstract Deletion of the multidrug resistance gene MRP1has been demonstrated in acute myeloid leukemia (AML) patients with inversion of chromosome 16 (inv[16]). These AML patients are known to have a relatively favorable prognosis, which suggests thatMRP1 might play an important role in determining clinical outcome. This study analyzed MRP1 deletion by fluorescent in situ hybridization (FISH), with a focus on inv(16) AML patients. Functional activity of multidrug resistance protein (MRP) was studied in a flow cytometric assay with the use of the MRP substrate carboxyfluorescein (CF) and the inhibitor MK-571. MRP1, MRP2, and MRP6 messenger RNA (mRNA) expression was determined with reverse transcriptase–polymerase chain reaction (RT-PCR). The results were compared with normal bone marrow cells. MRP1deletion was detected in 7 AML patients; 2 cases showed no MRP1FISH signals, and 5 cases had 1 MRP1 signal, whereas in 4 AML patients with inv(16) no MRP1 deletions were observed. A variability in MRP activity, expressed as CF efflux–blocking by MK-571, was observed (efflux-blocking factors varied between 1.2 and 3.6); this correlated with the number of MRP1 genes (r = 0.91, P < .01). MRP activity in the AML cases was not different from normal hematopoietic cells. MRP1 mRNA was detected in patients with 1 or 2 MRP1 FISH signals, but not in patients with no MRP1 signals. MRP2 and MRP6 mRNA were expressed predominantly in AML samples with 1 MRP1 signal, whereas in normal bone marrow cells no MRP2 and MRP6 mRNA was observed. In conclusion, this study shows that MRP activity varies among inv(16) AML cases and does not differ from that in normal hematopoietic cells; this might be in part due to the up-regulation of other MRP genes.

Deletion of the multidrug resistance protein MRP1 gene in acute myeloid leukemia: the impact on MRP activity

Blood ◽  
2000 ◽  
Vol 95 (11) ◽  
pp. 3514-3519
Author(s):  
Dorina M. van der Kolk ◽  
Edo Vellenga ◽  
Anneke Y. van der Veen ◽  
Leonore Noordhoek ◽  
Hetty Timmer-Bosscha ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Multidrug Resistance ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Multidrug Resistance Protein ◽  
Normal Bone Marrow ◽  
Normal Bone ◽  
Resistance Protein ◽  
Acute Myeloid

Deletion of the multidrug resistance gene MRP1has been demonstrated in acute myeloid leukemia (AML) patients with inversion of chromosome 16 (inv[16]). These AML patients are known to have a relatively favorable prognosis, which suggests thatMRP1 might play an important role in determining clinical outcome. This study analyzed MRP1 deletion by fluorescent in situ hybridization (FISH), with a focus on inv(16) AML patients. Functional activity of multidrug resistance protein (MRP) was studied in a flow cytometric assay with the use of the MRP substrate carboxyfluorescein (CF) and the inhibitor MK-571. MRP1, MRP2, and MRP6 messenger RNA (mRNA) expression was determined with reverse transcriptase–polymerase chain reaction (RT-PCR). The results were compared with normal bone marrow cells. MRP1deletion was detected in 7 AML patients; 2 cases showed no MRP1FISH signals, and 5 cases had 1 MRP1 signal, whereas in 4 AML patients with inv(16) no MRP1 deletions were observed. A variability in MRP activity, expressed as CF efflux–blocking by MK-571, was observed (efflux-blocking factors varied between 1.2 and 3.6); this correlated with the number of MRP1 genes (r = 0.91, P < .01). MRP activity in the AML cases was not different from normal hematopoietic cells. MRP1 mRNA was detected in patients with 1 or 2 MRP1 FISH signals, but not in patients with no MRP1 signals. MRP2 and MRP6 mRNA were expressed predominantly in AML samples with 1 MRP1 signal, whereas in normal bone marrow cells no MRP2 and MRP6 mRNA was observed. In conclusion, this study shows that MRP activity varies among inv(16) AML cases and does not differ from that in normal hematopoietic cells; this might be in part due to the up-regulation of other MRP genes.

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