Expression of erythropoietin receptor and in vitro functional effects of epoetins in B-cell malignancies.

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Kokhaei P, Abdalla AO, Hansson L, Mikaelsson E, Kubbies M, Haselbeck A, Jernberg-Wiklund H, Mellstedt H, Osterborg A

Expression of erythropoietin receptor and in vitro functional effects of epoetins in B-cell malignancies.

Clin Cancer Res. 2007 Jun 15;13(12):3536-44.

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17575216 [ View in PubMed

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Abstract

PURPOSE: Erythropoietin (EPO) and EPO receptor (EPO-R) expression have been reported in solid tumors and are claimed to regulate tumor growth; however, no data have been published on this issue in B-cell malignancies or normal lymphoid cells. This report describes genomic/protein EPO-R expression and in vitro effects of recombinant human EPO (epoetin) in B-cell chronic lymphocytic leukemia (B-CLL), mantle-cell lymphoma (MCL), and multiple myeloma (MM). EXPERIMENTAL DESIGN: Blood samples were obtained from patients with B-CLL, MCL, and healthy volunteers, and bone marrow was obtained from MM patients. EPO-R mRNA was detected by reverse transcription-PCR. EPO-R surface expression was investigated by flow cytometry using digoxigenin-labeled epoetin and polyclonal rabbit anti-EPO-R antibody for intracellular receptor. Tumor cell stimulation was determined in vitro using [(3)H]thymidine incorporation and CD69 expression after exposure to epoetin alpha or beta or darbepoetin alpha. RESULTS: EPO-R mRNA was detected in mononuclear cells from 32 of 41 (78%) B-CLL and 5 of 7 (71%) MCL patients, and 21 of 21 (100%) MM samples. Expression was also detected in highly purified T cells from six of eight B-CLL patients, four of four MM patients, and normal donor B and T cells. Surface EPO-R protein was not detected. Intracellular EPO-R staining with anti-EPO-R antibodies was unspecific. No tumor-stimulatory effect was observed with high epoetin concentrations. CONCLUSIONS: EPO-R gene is frequently expressed in lymphoid malignancies and normal B and T cells. However, there was no surface protein expression and no epoetin-induced in vitro stimulation of tumor B cells, indicating that epoetin therapy in vivo is likely to be safe in patients with lymphoid malignancies.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Darbepoetin alfa	Erythropoietin receptor	Protein	Humans	Yes	Agonist	Details
Erythropoietin	Erythropoietin receptor	Protein	Humans	Yes	Agonist	Details