Effects of 5-aza-2′-deoxycytidine on proliferation, differentiation and p15/INK4b regulation of human hematopoietic progenitor cells

Abstract

The demethylating agents 5-azacytidine and 5-aza-2'-deoxycytidine (DAC) have been shown to induce differentiation and inhibit growth of leukemic myeloid cells at low concentrations. However, the effect of DAC in changing the differentiation and proliferation behavior of normal human myeloid progenitors has rarely been investigated. Therefore, we established an in vitro model of normal hematopoietic differentiation, using CD34+ cells from mobilized peripheral blood, to study proliferation and colony formation, expression of several myeloid maturation markers and of the inhibitor of cyclin-dependent kinases p15/INK4b. Upon DAC treatment, cell growth was significantly decreased in a dose-dependent manner, without an increase in cytotoxicity. DAC treatment also resulted in a substantial increase of lysozyme-positive cells, which could be enhanced by G-CSF, a modest increase of myeloperoxidase+ and CD15+ cells, as well as an increase of colony-forming cells (CFU-GM) compared to control cells. p15/INK4b protein expression was strongly upregulated upon myeloid maturation, and additional DAC treatment did not change p15 expression or the methylation status of the p15 promoter at the noncytotoxic concentrations used. Taken together, these data indicate a role of DAC in changing myeloid progenitor cell expansion and differentiation. This model appears suitable also for global analyses of multiple differentially methylated genes.

S100A6 Overexpression Is Associated with Poor Prognosis and Is Epigenetically Up-Regulated in Gastric Cancer

“…S100A6 was expressed highest in the 5 mol/L 5-azacytidine-treated cells, and in the 10 mol/L 5-azacytidine-treated cells the expression was lower, which suggested 5-azacytidine may also affect cell proliferation with the increase in the concentration. 43 Thus, a dependence of the induction of S100A6 expression on 5-azacytidine treatment again indicates that DNA methylation is the mechanism involved in the control of activity of this gene. An understanding of these intimately correlated epigenetic changes may be of importance for predicting the outcome of patients with gastric cancer.…”

Epigenetic therapy of cancer stem and progenitor cells by targeting DNA methylation machineries

“…The differentiation inducing effect of Aza and Aza-dC has proven them to be promising therapeutic approaches aiming at induction of leukemic stem and progenitor cells toward non-malignant differentiated cells [57,58] . The induction ability of myeloid differentiation by Aza-dC in myeloid leukemic cells correlates with an upregulation of CD15, myeloperoxidase, lysozyme and the tumor suppressor p15 [59] . Several mechanisms have been proposed to underline Aza-and Aza-dC-induced differentiation of myeloid leukemia.…”

Discovery of epigenetically silenced genes in acute myeloid leukemias

“…3,4 The demethylating agent 5-aza-2 0 deoxycytidine (DAC) and the histone deacetylase inhibitor (HDACi) suberoyl anilide bishydroxamide (SAHA) have been shown to possess potent antitumorigenic properties against hematopoietic disorders. [5][6][7][8] Recently, 5-aza-cytidine, DAC's parental compound, was approved by the Food and Drug Administration (FDA) for the treatment of myelodysplastic syndromes (MDSs); and many clinical trials are underway using either DAC or HDACis to treat AML. [9][10][11][12][13] However, no reports have examined their effects on global transcription in myeloid disorders.…”