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RNA-dependent inhibition of ribonucleotide reductase is a major pathway for 5-azacytidine activity in acute myeloid leukemia
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| Zeitschriftentitel: | Blood |
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| Personen und Körperschaften: | , , , , , , , , , , |
| In: | Blood, 119, 2012, 22, S. 5229-5238 |
| Format: | E-Article |
| Sprache: | Englisch |
| veröffentlicht: |
American Society of Hematology
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| Schlagwörter: |
| Zusammenfassung: | <jats:title>Abstract</jats:title> <jats:p>5-Azacytidine (5-azaC) is an azanucleoside approved for myelodysplastic syndrome. Approximately 80%-90% of 5-azaC is believed to be incorporated into RNA, which disrupts nucleic acid and protein metabolism leading to apoptosis. A smaller fraction (10%-20%) of 5-azaC inhibits DNA methylation and synthesis through conversion to decitabine triphosphate and subsequent DNA incorporation. However, its precise mechanism of action remains unclear. Ribonucleotide reductase (RR) is a highly regulated enzyme comprising 2 subunits, RRM1 and RRM2, that provides the deoxyribonucleotides required for DNA synthesis/repair. In the present study, we found for the first time that 5-azaC is a potent inhibitor of RRM2 in leukemia cell lines, in a mouse model, and in BM mononuclear cells from acute myeloid leukemia (AML) patients. 5-azaC–induced RRM2 gene expression inhibition involves its direct RNA incorporation and an attenuated RRM2 mRNA stability. Therefore, 5-azaC causes a major perturbation of deoxyribonucleotide pools. We also demonstrate herein that the initial RR-mediated 5-azaC conversion to decitabine is terminated through its own inhibition. In conclusion, we identify RRM2 as a novel molecular target of 5-azaC in AML. Our findings provide a basis for its more widespread clinical use either alone or in combination.</jats:p> |
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| Umfang: | 5229-5238 |
| ISSN: |
0006-4971
1528-0020 |
| DOI: | 10.1182/blood-2011-11-382226 |