// <![CDATA[ $('.header-date').hide();$('#titleAuthors').hide();$('#abstractHeader').hide(); // ]]> Stefan Nagel1, Claudia Pommerenke1, Corinna Meyer1, Maren Kaufmann1, Hans G. Drexler1, Roderick A.F. MacLeod1 1Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany Correspondence to: Stefan Nagel, email: sna@dsmz.de Keywords: IL-7, IL7R, MEF2C, PRC1, PRC2 Received: March 02, 2016 Accepted: May 29, 2016 Published: June 13, 2016 ABSTRACT Recently, we identified deregulated expression of the B-cell specific transcription factor MEF2C in T-cell acute lymphoid leukemia (T-ALL). Here, we performed sequence analysis of a regulatory upstream section of MEF2C in T-ALL cell lines which, however, proved devoid of mutations. Unexpectedly, we found strong conservation between the regulatory upstream region of MEF2C (located at chromosomal band 5q14) and an intergenic stretch at 7q11 located between STAG3L4 and AUTS2, covering nearly 20 kb. While the non-coding gene STAG3L4 was inconspicuously expressed, AUTS2 was aberrantly upregulated in 6% of T-ALL patients (public dataset GSE42038) and in 3/24 T-ALL cell lines, two of which represented very immature differentiation stages. AUTS2 expression was higher in normal B-cells than in T-cells, indicating lineage-specific activity in lymphopoiesis. While excluding chromosomal aberrations, examinations of AUTS2 transcriptional regulation in T-ALL cells revealed activation by IL7-IL7R-STAT5-signalling and MEF2C. AUTS2 protein has been shown to interact with polycomb repressor complex 1 subtype 5 (PRC1.5), transforming this particular complex into an activator. Accordingly, expression profiling and functional analyses demonstrated that AUTS2 activated while PCGF5 repressed transcription of NKL homeobox gene MSX1 in T-ALL cells. Forced expression and pharmacological inhibition of EZH2 in addition to H3K27me3 analysis indicated that PRC2 repressed MSX1 as well. Taken together, we found that AUTS2 and MEF2C, despite lying on different chromosomes, share strikingly similar regulatory upstream regions and aberrant expression in T-ALL subsets. Our data implicate chromatin complexes PRC1/AUTS2 and PRC2 in a gene network in T-ALL regulating early lymphoid differentiation.

Leukemia is one of the leading journals in hematology and oncology. It is published monthly and covers all aspects of the research and treatment of leukemia and allied diseases. Studies of normal hemopoiesis are covered because of their comparative relevance.

NKL homeobox gene MSX1 acts like a tumor suppressor in NK-cell leukemia NKL homeobox gene MSX1 acts like a tumor suppressor in NK-cell leukemia

WT1 is a true chameleon, both acting as an oncogene and tumor suppressor. As its exact role in leukemogenesis is still ambiguous, research with model systems representing natural conditions surrounding the genetic alterations in WT1 is necessary. In a cohort of 59 leukemia/lymphoma cell lines, we showed aberrant expression for WT1 mRNA, which does not always translate into protein levels. We also analyzed the expression pattern of the four major WT1 protein isoforms in the cell lines and primary AML blasts with/without WT1 mutations and demonstrated that the presence of mutations does not influence these patterns. By introduction of key intronic and exonic sequences of WT1 into a lentiviral expression vector, we developed a unique tool that can stably overexpress the four WT1 isoforms at their naturally occurring tissue-dependent ratio. To develop better cellular model systems for WT1, we sequenced large parts of its gene locus and also other important myeloid risk factor genes and revealed previously unknown alterations. Functionally, inhibition of the nonsense-mediated mRNA decay machinery revealed that under natural conditions, the mutated WT1 alleles go through a robust degradation. These results offer new insights and model systems regarding the characteristics of WT1 in leukemia and lymphoma.

Certified cell line models provide ideal experimental platforms to answer countless scientific questions. The LL-100 panel is a cohort of cell lines that are broadly representative of all leukemia–lymphoma entities (including multiple myeloma and related diseases), rigorously authenticated and validated, and comprehensively annotated. The process of the assembly of the LL-100 panel was based on evidence and experience. To expand the genetic characterization across all LL-100 cell lines, we performed whole-exome sequencing and RNA sequencing. Here, we describe the conception of the panel and showcase some exemplary applications with a focus on cancer genomics. Due diligence was paid to exclude cross-contaminated and non-representative cell lines. As the LL-100 cell lines are so well characterized and readily available, the panel will be a valuable resource for identifying cell lines with mutations in cancer genes, providing superior model systems. The data also add to the current knowledge of the molecular pathogenesis of leukemia–lymphoma. Additional efforts to expand the breadth of available high-quality cell lines are clearly warranted.