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. 2012 Dec;91(12):1861-70.
doi: 10.1007/s00277-012-1537-8. Epub 2012 Aug 15.

Concomitant inhibition of DNA methyltransferase and BCL-2 protein function synergistically induce mitochondrial apoptosis in acute myelogenous leukemia cells

Twee Tsao  1 , Yuexi Shi, Steven Kornblau, Hongbo Lu, Sergej Konoplev, Ansu Antony, Vivian Ruvolo, Yi Hua Qiu, Ninaxiang Zhang, Kevin R Coombes, Michael Andreeff, Kensuke Kojima, Marina Konopleva
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VSports app下载 - Concomitant inhibition of DNA methyltransferase and BCL-2 protein function synergistically induce mitochondrial apoptosis in acute myelogenous leukemia cells

Twee Tsao et al. Ann Hematol. 2012 Dec.

Abstract (VSports)

DNA methylation and BLC-2 are potential therapeutic targets in acute myeloid leukemia (AML). We investigated pharmacologic interaction between the DNA methyltransferase inhibitor 5-azacytidine (5-AZA) and the BCL-2 inhibitor ABT-737. Increased BCL-2 expression determined by reverse phase protein analysis was associated with poor survival in AML patients with unfavorable cytogenetics (n = 195). We found that 5-AZA, which itself has modest apoptotic activity, acts synergistically with ABT-737 to induce apoptosis. The 5-AZA/ABT-737 combination enhanced mitochondrial outer membrane permeabilization, as evidenced by effective conformational activation of BAX and ∆ψ(m) loss. Although absence of p53 limited apoptotic activities of 5-AZA and ABT-737 as single agents, the combination synergistically induced apoptosis independent of p53 expression. 5-AZA down-regulated MCL-1, known to mediate resistance to ABT-737, in a p53-independent manner. The 5-AZA/ABT-737 combination synergistically induced apoptosis in AML cells in seven of eight patients. 5-AZA significantly reduced MCL-1 levels in two of three samples examined. Our data provide a molecular rationale for this combination strategy in AML therapy VSports手机版. .

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Conflict of interest statement

Disclosure of Potential Conflicts of Interest

The authors declare no competing financial interests.

V体育官网入口 - Figures

Figure 1
Figure 1. Increased BCL-2 expression predicts for poor survival in AML patients with unfavorable cytogenetics
(a) Histogram of BCL-2 expression in all AML patients relative to normal CD34+ cells. (b) BCL-2 expression levels in patients with AML classified according to FAB classification. (c) BCL-2 expression levels in patients with AML classified according to cytogenetic abnormalities. (d) Kaplan Meier curves for overall survival in patients with unfavorable cytogenetics.
Figure 2
Figure 2. 5-AZA and ABT-737 synergistically induce apoptosis in AML cells
(a) OCI-AML-3 and MOLM-13 cells were treated with a range of concentrations of 5-AZA and ABT-737 for 72 hours, either as individual agents or in combination, and the Annexin V-positive fractions were measured by flow cytometry. Results are expressed as mean ± SD. A minority of untreated cells (6.5 ± 0.9% in OCI-AML-3, 5.3 ± 0.6% in MOLM-13 and 4.8 ± 2.0% in HL-60 cells) was positive for Annexin V. (b) OCI-AML-3 cells were treated for 24 hours with 2 µM 5-AZA and 6 hours with 2 µM ABT-737, and BAX conformational change was determined. To block the caspase activation-mediated conformational change of BAX, cells were preincubated for 1 hour with 50 M Z-VAD-FMK. Results are expressed as mean SD of triplicate measurements. Asterisk (*) indicates significance at P < 0.01.
Figure 3
Figure 3. 5-AZA and ABT-737 synergistically induce mitochondrial apoptosis in AML cells irrespective of p53 expression
(a) OCI-AML-3 cells transduced with retroviruses encoding either scrambled shRNA (shC) or p53-specific shRNA (shp53), were treated for 72 hours with 250, 500, 1000 or 2000 nM 5-AZA and ABT-737, either as individual agents or in combination. The concentration ratio of ABT-737 to 5-AZA was 1:1. Annexin V–positive fractions were measured by flow cytometry. Results are expressed as mean ± SD. (b) OCI-AML-3 cells expressing scrambled shRNA (shC) or p53-specific shRNA (shp53), were treated for 18 hours with indicated concentrations of 5-AZA and ABT-737, either as individual agents or in combination. Δψm loss was determined. Results are expressed as mean ± SD.
Figure 4
Figure 4. 5-AZA reduces MCL-1 levels in a p53-independent manner
(a) OCI-AML-3 cells transduced with retroviruses encoding either scrambled shRNA (shC) or p53-specific shRNA (shp53) and were treated for 48 hours with 1 µM 5-AZA. (b) Primary AML cells from 3 patients were incubated for 72 hours with the indicated concentrations of 5-AZA.
Figure 5
Figure 5. 5-AZA and ABT-737 decrease the infiltrated CD45+ human leukemic cells in spleen
Mouse spleen sections were stained with hematoxylin and eosin (H.E.) and anti-human CD45. The frequency of CD45+ cells enumerated by pathologist was as following: control, 30%; 5-AZA, 3%; ABT-737, 10%; 5-AZA+ABT-737, 0%.
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References

    1. Yip KW, Reed JC. Bcl-2 family proteins and cancer. Oncogene. 2008;27:6398–6406. - PubMed
    1. Kornblau SM, Vu HT, Ruvolo P, et al. BAX and PKC modulate the prognostic impact of BCL2 expression in acute myelogenous leukemia. Clin Cancer Res. 2000;6:1401–1409. - PubMed
    1. Oltersdorf T, Elmore SW, Shoemaker AR, et al. An inhibitor of BCL-2 family proteins induces regression of solid tumours. Nature. 2005;435:677–681. - PubMed
    1. Konopleva M, Contractor R, Tsao T, et al. Mechanisms of apoptosis sensitivity and resistance to the BH3 mimetic ABT-737 in acute myeloid leukemia. Cancer Cell. 2006;10:375–388. - "VSports手机版" PubMed
    1. Roberts AW, Seymour JF, Brown JR, et al. Substantial susceptibility of chronic lymphocytic leukemia to BCL2 inhibition: results of a phase I study of navitoclax in patients with relapsed or refractory disease. J Clin Oncol. 2012;30:488–496. - PMC - PubMed

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