Toxicity of 3'-azido-3'-deoxythymidine and 9-(1,3-dihydroxy-2-propoxymethyl)guanine for normal human hematopoietic progenitor cells in vitro

Abstract

The effects of 3'-azido-3'-deoxythymidine (AZT) and 9-(1,3-dihydroxy-2-propoxymethyl)guanine on myeloid and erythroid colony-forming cells were studied by clonogenic assays. Both consistently inhibited granulocytemacrophage CFU (CFU-GM) and erythroid burst-forming units in a dose-dependent fashion. Concentrations of AZT and 9-(1,3-dihydroxy-2-propoxymethyl)guanine required for 50% inhibition of CFU-GM were, respectively, 0.9 0.1 and 2.7 0.5 ,uM; those required for 90% inhibition were, respectively, 34.0 2.8 and 35.7 + 3.6 ,uM. Erythroid burst-forming units were less sensitive to high concentrations of AZT than were CFU-GM.3'-Azido-3'-deoxythymidine (AZT), an inhibitor of the human immunodeficiency virus reverse transcriptase, is, at the present time, one of the most promising drugs available for the treatment of acquired immunodeficiency syndrome (AIDS). 9-(1,3-Dihydroxy-2-propoxymethyl)guanine (DHPG), an inhibitor of the cytomegalovirus DNA polymerase (2), has shown encouraging results in the treatment of life-threatening cytomegalovirus infections, a frequent cause of severe morbidity in AIDS patients. The side effects of these agents and especially their myelosuppressive activities have been of some concern in preliminary clinical trials (3,13). Surprisingly, little attention has been given thus far to the effects of these antiviral drugs on such "host" cells as those of bone marrow. This has led to our study of the effects of AZT and DHPG on the growth of normal human hematopoietic progenitor cells (specifically granulocytes-macrophages and erythrocytes) in vitro, with the results set forth in the present report.Bone marrow cells obtained by aspiration from the posterior iliac crest of healthy volunteers who had given informed consent were anticoagulated with heparin and layered on a single-step Ficoll-Hypaque discontinuous gradient to remove mature erythroid and myeloid cells. The mononuclear cells, obtained from the interface of the gradient, were collected and washed twice in Hanks balanced salt solution.The culture assay for granulocyte-macrophage CFU (CFU-GM) was performed by using the modified bilayer soft-agar system described by Metcalf et al. (9). Briefly, the bottom or feeder layer was composed of 0.5% agar (BactoAgar; Difco Laboratories, Detroit, Mich.) containing McCoy 5A nutrient medium supplemented with 15% dialyzed fetal bovine serum (heat inactivated at 56°C for 30 min) (GIBCO Laboratories, Grand Island, N.Y.) and 10% (final concentration) giant cell tumor-conditioned medium (GIBCO) as a source of colony-stimulating factor. The desired drug concentrations (or drug diluent for the control) were added to * Corresponding author.this layer, and 1-ml volumes of this mixture were poured into 35-mm plastic petri dishes. After solidification, a top layer (1 ml) was prepared which contained 0.3% agar, McCoy SA nutrient medium supplemented with 15% fetal bovine serum, and 105 mononuclear cells per ml. The plates were incubated for 14 days in a humidified atmosphere of 5% C02-95% air at 37°C. Colonies c...

Cytopenias after day 28 in allogeneic hematopoietic cell transplantation: impact of recipient/donor factors, transplant conditions and myelotoxic drugs

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Blood eosinophilia after unrelated cord blood transplantation for adults

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Synergistic Anti-Human Immunodeficiency Viral (HIV-1) Effect of the Immunomodulator Ampligen (Mismatched Double-Stranded RNA) with Inhibitors of Reverse Transcriptase and HIV-1 Regulatory Proteins

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