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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MEK inhibition causes cell cycle arrest and modulates p27Kip1 and p21Waf...
MEK inhibition causes cell cycle arrest and modulates p27Kip1 and p21Waf1/CIP1 expression. (a) OCI-AML3 (open circles), HL-60 (filled circles), and freshly isolated leukemic blasts from patient 3 (filled squares) were cultured for 48 hours in the presence of DMSO or PD98059 at the indicated concentrations, and then 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. (b) OCI-AML3, HL-60, and U937 cells were cultured for 24 hours in the presence of DMSO or PD98059 (20 μM), and subjected to Western blot analysis with mAb’s specific for the indicated cell cycle–regulating proteins. Results are representative of one of three independent experiments. (c) OCI-AML3 cells were cultured for the indicated times in the presence of DMSO or PD98059 (20 μM), and subjected to quantitative real-time PCR analysis of p21Waf1/CIP1 (filled circles) and p27Kip1 (open circles) RNA transcripts. Results are expressed as percentage of specific RNA transcripts in the DMSO-treated group and are representative of one of two independent experiments. (d) OCI-AML3 cells were cultured for the indicated times in the presence of DMSO or PD98059 (20 μM) and assessed for DNA content. Results are expressed as percentage of S-phase cells in the DMSO-treated group. Two hours after the addition of PD98059, cells were lysed, and the phosphorylation status of p27 Kip1 was analyzed by Western blot using T187-phosphospecific Ab’s (p-p27Kip1).