B-cell precursor childhood acute lymphoblastic leukemia with ETV6-RUNX1 (TEL-AML1) fusion has an overall good prognosis, but relapses occur, usually after cessation of treatment and occasionally many years later. We have investigated the clonal origins of relapse by comparing the profiles of genomewide copy number alterations at presentation in 21 patients with those in matched relapse (12-119 months). We identified, in total, 159 copy number alterations at presentation and 231 at relapse (excluding Ig/TCR). Deletions of CDKN2A/B or CCNC (6q16.2-3) or both increased from 38% at presentation to 76% in relapse, suggesting that cell-cycle deregulation contributed to emergence of relapse. A novel observation was recurrent gain of chromosome 16 (2 patients at presentation, 4 at relapse) and deletion of plasmocytoma variant translocation 1 in 3 patients. The data indicate that, irrespective of time to relapse, the relapse clone was derived from either a major or minor clone at presentation. Backtracking analysis by FISH identified a minor subclone at diagnosis whose genotype matched that observed in relapse ∼ 10 years later. These data indicate subclonal diversity at diagnosis, providing a variable basis for intraclonal origins of relapse and extended periods (years) of dormancy, possibly by quiescence, for stem cells in ETV6-RUNX1(+) acute lymphoblastic leukemia.

• MeSH
• akutní lymfatická leukemie genetika   metabolismus   mortalita   terapie   MeSH
• cyklin C MeSH
• dítě MeSH
• fúzní onkogenní proteiny genetika   metabolismus   MeSH
• inhibitor p15 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• inhibitor p16 cyklin-dependentní kinasy genetika   metabolismus   MeSH
• lidé MeSH
• lidské chromozomy, pár 16 genetika   metabolismus   MeSH
• lidské chromozomy, pár 6 genetika   metabolismus   MeSH
• předškolní dítě MeSH
• protein PEBP2A2 MeSH
• recidiva MeSH
• sekvenční delece * MeSH
• translokace genetická * MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Publikační typ
• abstrakt z konference MeSH

PURPOSE: Chimeric transcription factor ETV6/RUNX1 (TEL/AML1) is believed to cause pathologic block in lymphoid cell development via interaction with corepressor complex and histone deacetylase. We wanted to show the regulatory effect of ETV6/RUNX1 and its reversibility by histone deacetylase inhibitors (HDACi), as well as to identify potential ETV6/RUNX1-regulated genes. EXPERIMENTAL DESIGN: We used luciferase assay to show the interaction of ETV6/RUNX1 protein, ETV6/RUNX1-regulated gene, and HDACi. To identify ETV6/RUNX1-regulated genes, we used expression profiling and HDACi in lymphoid cells. Next, using the flow cytometry and quantitative reverse transcription-PCR, we measured differentiation changes in gene and protein expression after HDACi treatment. RESULTS: Luciferase assay showed repression of granzyme B expression by ETV6/RUNX1 protein and the reversibility of this effect by HDACi. Proving this regulatory role of ETV6/RUNX1, we identified, using complex statistical analysis, 25 genes that are potentially regulated by ETV6/RUNX1 protein. In four selected genes with known role in the cell cycle regulation (JunD, ACK1, PDGFRB, and TCF4), we confirmed expression changes after HDACi by quantitative analysis. After HDACi treatment, ETV6/RUNX1-positive cells showed immunophenotype changes resembling differentiation process compared with other leukemic cells (BCR/ABL, ETV6/PDGFRB positive). Moreover, ETV6/RUNX1-positive leukemic cells accumulated in G(1)-G(0) phase after HDACi whereas other B-lineage leukemic cell lines showed rather unspecific changes including induction of apoptosis and decreased proliferation. CONCLUSIONS: Presented data support the hypothesis that HDACi affect ETV6/RUNX1-positive cells via direct interaction with ETV6/RUNX1 protein and that treatment with HDACi may release aberrant transcription activity caused by ETV6/RUNX1 chimeric transcription factor.

• MeSH
• apoptóza účinky záření   MeSH
• granzymy genetika   MeSH
• histondeacetylasy MeSH
• inhibitory histondeacetylas MeSH
• lidé MeSH
• lymfoidní leukemie genetika   patologie   MeSH
• lymfopoéza genetika   účinky léků   MeSH
• nádorové buňky kultivované MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proliferace buněk účinky léků   MeSH
• protein PEBP2A2 fyziologie   genetika   MeSH
• protoonkogenní proteiny c-ets fyziologie   genetika   MeSH
• regulace genové exprese u leukemie účinky léků   MeSH
• represorové proteiny fyziologie   genetika   MeSH
• stanovení celkové genové exprese MeSH
• Check Tag
• lidé MeSH