Mechanism of inhibition of T-acute lymphoblastic leukemia cells by PNP inhibitor—BCX-1777
| Autor: | Cynthia Parker, Ramanda Upshaw, Sandya L Ananth, Shanta Bantia, LaShun L Horn |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
T cell
Immunology Purine nucleoside phosphorylase Apoptosis Pyrimidinones Biology Cell Line T Acute Lymphoblastic Leukemia chemistry.chemical_compound Nucleotidase medicine Humans Leukemia-Lymphoma Adult T-Cell Immunology and Allergy Deoxyguanosine Pyrroles heterocyclic compounds Lymphocytes Pharmacology Purine Nucleosides T lymphocyte Molecular biology HIV Reverse Transcriptase Culture Media Stavudine medicine.anatomical_structure Purine-Nucleoside Phosphorylase chemistry Biochemistry Lamivudine Cell culture Reverse Transcriptase Inhibitors Cell Division Half-Life |
| Zdroj: | International Immunopharmacology. 3:879-887 |
| ISSN: | 1567-5769 |
| Popis: | Purine nucleoside phosphorylase (PNP) deficiency in humans produces a relatively selective depletion of T cells. BCX-1777 is a potent inhibitor of PNP. BCX-1777 in the presence of deoxyguanosine (dGuo) inhibits the proliferation of CEM-SS [T-acute lymphoblastic leukemia (T-ALL)] cells with an IC(50)=0.015 microM. This inhibition by BCX-1777 and dGuo is accompanied by elevation of dGTP (154-fold) and dATP (8-fold). Deoxycytidine (dCyt) completely and lamivudine (3TC) partially reverse this inhibition caused by BCX-1777 and dGuo. dNTP analysis of these samples indicates that, in the presence of dCyt, where complete reversal of inhibition is observed, dGTP and dATP pools revert back to the control levels. In samples containing 3TC, where partial reversal of inhibition was observed, dGTP decreased from 154-fold to 38-fold and dATP levels further increased from 8-fold to 30-fold compared to the control sample. In CEM-SS cells, inhibition of proliferation by BCX-1777 and dGuo is not due to accumulation of dATP because in the presence of 3TC, where reversal of inhibition is observed, dATP levels are further increased. These studies clearly indicate that inhibition of T cells is due to accumulation of dGTP resulting in cell death with characteristics of apoptosis. The half-life of dGTP in CEM-SS cells is 18 h, which is longer than that observed in human lymphocytes (4 h), suggesting that the nucleotidase level in CEM-SS cells is lower than in human lymphocytes. A 154-fold accumulation of dGTP in CEM-SS cells in the presence of BCX-1777 and dGuo compared to a 15-fold accumulation of dGTP in human lymphocytes suggests that kinase level is higher in CEM-SS cells compared to human lymphocytes. High kinase and low nucleotidase levels make CEM-SS cells more sensitive to inhibition by BCX-1777 and dGuo than human lymphocytes. Currently, BCX-1777 is in phase I/II clinical trial for the treatment of T cell malignancies. |
| Databáze: | OpenAIRE |
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