Therapeutic targeting of the MEK/MAPK signal transduction module in acute myeloid leukemia
Michele Milella, … , Elihu Estey, Michael Andreeff
Michele Milella, … , Elihu Estey, Michael Andreeff
Published September 15, 2001
Citation Information: J Clin Invest. 2001;108(6):851-859. https://doi.org/10.1172/JCI12807.
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Article

Therapeutic targeting of the MEK/MAPK signal transduction module in acute myeloid leukemia

Abstract

The mitogen-activated protein kinase (MAPK) pathway regulates growth and survival of many cell types, and its constitutive activation has been implicated in the pathogenesis of a variety of malignancies. In this study we demonstrate that small-molecule MEK inhibitors (PD98059 and PD184352) profoundly impair cell growth and survival of acute myeloid leukemia (AML) cell lines and primary samples with constitutive MAPK activation. These agents abrogate the clonogenicity of leukemic cells but have minimal effects on normal hematopoietic progenitors. MEK blockade also results in sensitization to spontaneous and drug-induced apoptosis. At a molecular level, these effects correlate with modulation of the expression of cyclin-dependent kinase inhibitors (p27Kip1 and p21Waf1/CIP1) and antiapoptotic proteins of the inhibitor of apoptosis proteins (IAP) and Bcl-2 families. Interruption of constitutive MEK/MAPK signaling therefore represents a promising therapeutic strategy in AML.

Authors

Michele Milella, Steven M. Kornblau, Zeev Estrov, Bing Z. Carter, Hélène Lapillonne, David Harris, Marina Konopleva, Shourong Zhao, Elihu Estey, Michael Andreeff

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Figure 5

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Effect of PD184352 on AML cell lines and primary samples. (a) OCI-AML3 c...
Effect of PD184352 on AML cell lines and primary samples. (a) OCI-AML3 cells were exposed to DMSO (C) or PD184352 for 6 hours and analyzed for MAPK phosphorylation. (b) OCI-AML3 cells were cultured in the presence of DMSO or PD184352. After 96 hours, cells were assessed for viability (open circles) and DNA content (filled circles). Results show viable cells in the PD98059-treated group, expressed as percentage of the viable cells in the DMSO-treated group, and percentage of cells with a hypodiploid DNA content, respectively, and are representative of one of three independent experiments. (c) OCI-AML3 (open circles), HL-60 (filled circles), and leukemic blasts from patient 19 (open squares) were cultured in the presence of DMSO or PD184352 for 48 hours and stained for DNA content. Results are expressed as percentage of S-phase cells in the DMSO-treated group. Cell line results are representative of one of three independent experiments. (d) The MAPK phosphorylation status of AML cell lines was assessed by Western blot. The ratio of phosphorylated to total p42MAPK was then plotted against the IC50 of PD184352 for the corresponding cell lines, and regression analysis was performed (R2 = 0.8933, P = 0.015). (e) CD34+ cells from healthy donors (n = 3) and blasts from AML patients (n = 7) were analyzed for phosphorylated MAPK by Western blot. Patient samples showing a greater than 25% decrease (from patients 14, 19, 21, and 24) and a less than 25% decrease (from patients 17, 20, and 22) in cell viability after in vitro exposure to MEK inhibitors are labeled as sensitive and resistant, respectively.