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Targeting fusion protein/corepressor contact restores differentiation response in leukemia cells
Author(s) -
Racanicchi Serena,
Maccherani Chiara,
Liberatore Concetta,
Billi Monia,
Gelmetti Vania,
Panigada Maddalena,
Rizzo Giovanni,
Nervi Clara,
Grignani Francesco
Publication year - 2005
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600593
Subject(s) - corepressor , biology , humanities , philosophy , genetics , gene , psychological repression , gene expression
The AML1/ETO and PML/RARα leukemia fusion proteins induce acute myeloid leukemia by acting as transcriptional repressors. They interact with corepressors, such as N‐CoR and SMRT, that recruit a multiprotein complex containing histone deacetylases on crucial myeloid differentiation genes. This leads to gene repression contributing to generate a differentiation block. We expressed in leukemia cells containing PML/RARα and AML1/ETO N‐CoR protein fragments derived from fusion protein/corepressor interaction surfaces. This blocks N‐CoR/SMRT binding by these fusion proteins, and disrupts the repressor protein complex. In consequence, the expression of genes repressed by these fusion proteins increases and differentiation response to vitamin D3 and retinoic acid is restored in previously resistant cells. The alteration of PML/RARα–N‐CoR/SMRT connections triggers proteasomal degradation of the fusion protein. The N‐CoR fragments are biologically effective also when directly transduced by virtue of a protein transduction domain. Our data indicate that fusion protein activity is permanently required to maintain the leukemia phenotype and show the route to developing a novel therapeutic approach for leukemia, based on its molecular pathogenesis.