EDAG regulates the proliferation and differentiation of hematopoietic cells and resists cell apoptosis through the activation of nuclear factor-κB

Abstract

Erythroid differentiation-associated gene (EDAG) is considered to be a human hematopoiesis-specific gene. Here, we reported that downregulation of EDAG protein in K562 cells resulted in inhibition of growth and colony formation, and enhancement of sensitivity to erythroid differentiation induced by hemin. Overexpression of EDAG in HL-60 cells significantly blocked the expression of the monocyte/ macrophage differentiation marker CD11b after pentahydroxytiglia myristate acetate induction. Moreover, overexpression of EDAG in pro-B Ba/F3 cells prolonged survival and increased the expression of c-Myc, Bcl-2 and Bcl-xL in the absence of interleukin-3 (IL-3). Furthermore, we showed that EDAG enhanced the transcriptional activity of nuclear factorkappa B (NF-jB), and high DNA-binding activity of NF-jB was sustained in Ba/F3 EDAG cells after IL-3 was withdrawn. Inhibition of NF-jB activity resulted in promoting Ba/F3 EDAG cells death. These results suggest that EDAG regulates the proliferation and differentiation of hematopoietic cells and resists cell apoptosis through the activation of NF-jB.

The mitochondrial serine protease HtrA2/Omi cleaves RIP1 during apoptosis of Ba/F3 cells induced by growth factor withdrawal

“…promoting genes [1], it has been proposed that cell fate following growth factor withdrawal is determined by the ability to maintain NF-κB activity [31][32][33]. In line with this notion, previous studies observed a large decrease in NF-κB activity before the propagation of apoptosis when Ba/F3 cells were deprived of IL-3 [30].…”

“…Indeed, Ba/F3 cells become committed to apoptosis when deprived of IL-3, and hence multiple signaling pathways downstream of IL-3 have been proposed to prevent apoptosis [29]. For instance, the constitutive activation of NF-κB in the presence of IL-3 is required for the survival of Ba/F3 cells [30][31][32]. As NF-κB activation is known to protect cells against apoptosis through the transcriptional upregulation of survival- At the indicated time points, cell death was assessed by cytofluorometric analysis of PI uptake.…”

The GATA site-dependent hemogen promoter is transcriptionally regulated by GATA1 in hematopoietic and leukemia cells

“…2 EDAG is highly expressed in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) and has been demonstrated to be involved in erythroleukemia differentiation, survival and apoptosis and cell transformation of NIH3T3 cells. 4,5 ALL these studies suggest that overexpression of EDAG in acute leukemia may play an important role in leukemogensis. More recently, assocaition of overexpression of EDAG and no remission in de novo AML has been reported: this result suggests that EDAG may play a modulator role in AML and could be a new target in the treatment of AML.…”

High expression of EDAG and its significance in AML

“…Overexpression of EDAG in NIH3T3 cells causes cell transforming and tumor forming in nude mice. 2 Furthermore, EDAG gene maps to chromosome 9q22, which contains a cluster of leukemic breakpoints and genes important for leukemogenesis. 1 However, its clinical significance and function in leukemogenesis is still unclear.…”

“…This accords with the reports of others. 2 In this study, we also studied the effect of knockdown of EDAG expression by RNAi on the expression of some genes related to cell cycle, apoptosis or hematopoiesis, including cyclin A1, cyclin D1, cyclin D2, cyclin E, cdk2, p21, SCL/tal-1, GATA-2, c-myb, c-Myc, Bcl-2, NF-kB, and Notch1 (Figure 2). We found that p21 expression was increased in the EDAG knockdown K562 cells.…”