Publications by authors named "Hans G Drexler"

182 Publications

NKL Homeobox Gene VENTX Is Part of a Regulatory Network in Human Conventional Dendritic Cells.

Int J Mol Sci 2021 May 31;22(11). Epub 2021 May 31.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany.

Recently, we documented a hematopoietic NKL-code mapping physiological expression patterns of NKL homeobox genes in human myelopoiesis including monocytes and their derived dendritic cells (DCs). Here, we enlarge this map to include normal NKL homeobox gene expressions in progenitor-derived DCs. Analysis of public gene expression profiling and RNA-seq datasets containing plasmacytoid and conventional dendritic cells (pDC and cDC) demonstrated HHEX activity in both entities while cDCs additionally expressed VENTX. The consequent aim of our study was to examine regulation and function of VENTX in DCs. We compared profiling data of VENTX-positive cDC and monocytes with VENTX-negative pDC and common myeloid progenitor entities and revealed several differentially expressed genes encoding transcription factors and pathway components, representing potential VENTX regulators. Screening of RNA-seq data for 100 leukemia/lymphoma cell lines identified prominent VENTX expression in an acute myelomonocytic leukemia cell line, MUTZ-3 containing inv(3)(q21q26) and t(12;22)(p13;q11) and representing a model for DC differentiation studies. Furthermore, extended gene analyses indicated that MUTZ-3 is associated with the subtype cDC2. In addition to analysis of public chromatin immune-precipitation data, subsequent knockdown experiments and modulations of signaling pathways in MUTZ-3 and control cell lines confirmed identified candidate transcription factors CEBPB, ETV6, EVI1, GATA2, IRF2, MN1, SPIB, and SPI1 and the CSF-, NOTCH-, and TNFa-pathways as VENTX regulators. Live-cell imaging analyses of MUTZ-3 cells treated for VENTX knockdown excluded impacts on apoptosis or induced alteration of differentiation-associated cell morphology. In contrast, target gene analysis performed by expression profiling of knockdown-treated MUTZ-3 cells revealed VENTX-mediated activation of several cDC-specific genes including CSFR1, EGR2, and MIR10A and inhibition of pDC-specific genes like RUNX2. Taken together, we added NKL homeobox gene activities for progenitor-derived DCs to the NKL-code, showing that VENTX is expressed in cDCs but not in pDCs and forms part of a cDC-specific gene regulatory network operating in DC differentiation and function.
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http://dx.doi.org/10.3390/ijms22115902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198381PMC
May 2021

Leukemia Cell Lines: In Vitro Models for the Study of Chronic Neutrophilic Leukemia.

Curr Oncol 2021 05 10;28(3):1790-1794. Epub 2021 May 10.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany.

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm that is genetically characterized by the absence of both the Philadelphia chromosome and BCR-ABL1 fusion gene and the high prevalence of mutations in the colony-stimulating factor 3 receptor (CSF3R). Additional disease-modifying mutations have been recognized in CNL samples, portraying a distinct mutational landscape. Despite the growing knowledge base on genomic aberrations, further progress could be gained from the availability of representative models of CNL. To address this gap, we screened a large panel of available leukemia cell lines, followed by a detailed mutational investigation with focus on the CNL-associated candidate driver genes. The sister cell lines CNLBC-1 and MOLM-20 were derived from a patient with CNL and carry CNL-typical molecular hallmarks, namely mutations in several genes, such as CSF3R, ASXL1, EZH2, NRAS, and SETBP1. The use of these validated and comprehensively characterized models will benefit the understanding of the pathobiology of CNL and help inform therapeutic strategies.
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http://dx.doi.org/10.3390/curroncol28030166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8161829PMC
May 2021

Proposal for the designation of the natural killer antigens-positive γδ T-cell subset as γδ NKT-cells: nomenclature based on immunoprofile.

Hum Cell 2021 Jul 11;34(4):1278-1279. Epub 2021 Apr 11.

Technical University of Braunschweig, Faculty of Life Sciences, 38126, Braunschweig, Germany.

Natural killer T (NKT)-cells with both T- and NK-cell antigens can be classified into αβ or γδ type according to the TCR gene expression. The WHO classification of lymphoid neoplasms did not further subdivide the above-mentioned NKT-cell malignancies according to the expression of these TCR types. γδ T-cells can be stimulated and expanded by Zoledronic acid, usually carrying Vγ9 Vδ2 TCR and various NK-associated receptors (NKR) such as CD56, CD94, CD158a, CD158b, CD161, etc. In contrast, αβ T-type NKT-cells are positive for Vα24 Vβ11 TCR. NKR positive γδ T-cells have clearly different features than the NKT-cells with Vα24 Vβ11 TCR type, αβ NKT. NKT-cells carrying γδ TCR should be classified and named as γδ NKT-cells to distinguish the cells explicitly from αβ NKT-cells.
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http://dx.doi.org/10.1007/s13577-021-00531-1DOI Listing
July 2021

Establishment of the TALE-code reveals aberrantly activated homeobox gene PBX1 in Hodgkin lymphoma.

PLoS One 2021 4;16(2):e0246603. Epub 2021 Feb 4.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

Homeobox genes encode transcription factors which regulate basic processes in development and cell differentiation and are grouped into classes and subclasses according to sequence similarities. Here, we analyzed the activities of the 20 members strong TALE homeobox gene class in early hematopoiesis and in lymphopoiesis including developing and mature B-cells, T-cells, natural killer (NK)-cells and innate lymphoid cells (ILC). The resultant expression pattern comprised eleven genes and which we termed TALE-code enables discrimination of normal and aberrant activities of TALE homeobox genes in lymphoid malignancies. Subsequent expression analysis of TALE homeobox genes in public datasets of Hodgkin lymphoma (HL) patients revealed overexpression of IRX3, IRX4, MEIS1, MEIS3, PBX1, PBX4 and TGIF1. As paradigm we focused on PBX1 which was deregulated in about 17% HL patients. Normal PBX1 expression was restricted to hematopoietic stem cells and progenitors of T-cells and ILCs but absent in B-cells, reflecting its roles in stemness and early differentiation. HL cell line SUP-HD1 expressed enhanced PBX1 levels and served as an in vitro model to identify upstream regulators and downstream targets in this malignancy. Genomic studies of this cell line therein showed a gain of the PBX1 locus at 1q23 which may underlie its aberrant expression. Comparative expression profiling analyses of HL patients and cell lines followed by knockdown experiments revealed NFIB and TLX2 as target genes activated by PBX1. HOX proteins operate as cofactors of PBX1. Accordingly, our data showed that HOXB9 overexpressed in HL coactivated TLX2 but not NFIB while activating TNFRSF9 without PBX1. Further downstream analyses showed that TLX2 activated TBX15 which operated anti-apoptotically. Taken together, we discovered a lymphoid TALE-code and identified an aberrant network around deregulated TALE homeobox gene PBX1 which may disturb B-cell differentiation in HL by reactivation of progenitor-specific genes. These findings may provide the framework for future studies to exploit possible vulnerabilities of malignant cells in therapeutic scenarios.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246603PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861379PMC
August 2021

Modulators of histone demethylase JMJD1C selectively target leukemic stem cells.

FEBS Open Bio 2021 01 16;11(1):265-277. Epub 2020 Dec 16.

Laboratory for Stem Cell and Regenerative Medicine & Clinical Research Center, The Affiliated Hospital of Weifang Medical University, China.

Leukemic stem cells (LSCs) comprise a very rare cell population that results in the development of acute myeloid leukemia. The selective targeting of drivers in LSCs with small molecule inhibitors holds promise for treatment of acute myeloid leukemia. Recently, we reported the identification of inhibitors of the histone lysine demethylase JMJD1C that preferentially kill MLL rearranged acute leukemia cells. Here, we report the identification of jumonji domain modulator #7 (JDM-7). Surface plasmon resonance analysis showed that JDM-7 binds to JMJD1C and its family homolog JMJD1B. JDM-7 did not significantly suppress cell proliferation in liquid cell culture at higher doses, although it led to a significant decrease in semi-solid colony formation experiments at lower concentrations. Moreover, low doses of JDM-7 did not suppress the proliferation of erythroid progenitor cells. We identified that JDM-7 downregulates the LSC self-renewal gene HOXA9 in leukemia cells. We further found that the structure of JDM-7 is similar to that of tadalafil, a drug approved by the US Food and Drug Administration. Molecular docking and surface plasmon resonance analysis showed that tadalafil binds to JMJD1C. Moreover, similar to JDM-7, tadalafil suppressed colony formation of leukemia cells in semi-solid cell culture at a concentration that did not affect primary umbilical cord blood cells. In summary, we have identified JDM-7 and tadalafil as potential JMJD1C modulators that selectively inhibit the growth of LSCs.
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http://dx.doi.org/10.1002/2211-5463.13054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7780120PMC
January 2021

Aberrant expression of NKL homeobox genes HMX2 and HMX3 interferes with cell differentiation in acute myeloid leukemia.

PLoS One 2020 13;15(10):e0240120. Epub 2020 Oct 13.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

The NKL-code describes normal expression patterns of NKL homeobox genes in hematopoiesis. Aberrant expression of NKL homeobox gene subclass members have been reported in several hematopoietic malignancies including acute myeloid leukemia (AML). Here, we analyzed the oncogenic role of the HMX-group of NKL homeobox genes in AML. Public expression profiling data-available for HMX1 and HMX2-indicate aberrant activity of HMX2 in circa 2% AML patients overall, rising to 31% in those with KMT2A/MLL rearrangements whereas HMX1 expression remains inconspicuous. AML cell lines EOL-1, MV4-11 and MOLM-13 expressed both, HMX2 and neighboring HMX3 genes, and harbored KMT2A aberrations, suggesting their potential functional association. Surprisingly, knockdown experiments in these cell lines demonstrated that KMT2A inhibited HMX2/3 which, in turn, did not regulate KMT2A expression. Furthermore, karyotyping and genomic profiling analysis excluded rearrangements of the HMX2/3 locus in these cell lines. However, comparative expression profiling and subsequent functional analyses revealed that IRF8, IL7- and WNT-signalling activated HMX2/3 expression while TNFa/NFkB- signalling proved inhibitory. Whole genome sequencing of EOL-1 identified two mutations in the regulatory upstream regions of HMX2/3 resulting in generation of a consensus ETS-site and transformation of a former NFkB-site into an SP1-site. Reporter-gene assays demonstrated that both mutations contributed to HMX2/3 activation, modifying ETS1/ELK1- and TNFalpha-mediated gene regulation. Moreover, DMSO-induced eosinophilic differentiation of EOL-1 cells coincided with HMX2/3 downregulation while knockdown of HMX2 induced cell differentiation, collectively supporting a fundamental role for these genes in myeloid differentiation arrest. Finally, target genes of HMX2/3 were identified in EOL-1 and included suppression of differentiation gene EPX, and activation of fusion gene FIP1L1-PDGFRA and receptor-encoding gene HTR7, both of which enhanced oncogenic ERK-signalling. Taken together, our study documents a leukemic role for deregulated NKL homeobox genes HMX2 and HMX3 in AML, revealing molecular mechanisms of myeloid differentiation arrest.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0240120PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7553312PMC
December 2020

The NKL-code for innate lymphoid cells reveals deregulated expression of NKL homeobox genes HHEX and HLX in anaplastic large cell lymphoma (ALCL).

Oncotarget 2020 Aug 25;11(34):3208-3226. Epub 2020 Aug 25.

Department of Human and Animal Cell Lines, Leibniz Institute, DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

NKL homeobox genes encode developmental transcription factors and display an NKL-code according to their physiological expression pattern in hematopoiesis. Here, we analyzed public transcriptome data from primary innate lymphoid cells (ILCs) for NKL homeobox gene activities and found that ILC3 expressed exclusively HHEX while in ILC1 and ILC2 these genes were silenced. Deregulation of the NKL-code promotes hematopoietic malignancies, including anaplastic large cell lymphoma (ALCL) which reportedly may derive from ILC3. Accordingly, we analyzed NKL homeobox gene activities in ALCL cell lines and investigated their role in this malignancy. Transcriptome analyses demonstrated low expression levels of HHEX but powerfully activated HLX. Forced expression of HHEX in ALCL cell lines induced genes involved in apoptosis and ILC3 differentiation, indicating tumor suppressor activity. ALCL associated NPM1-ALK and JAK-STAT3-signalling drove enhanced expression of HLX while discounting HHEX. Genomic profiling revealed copy number gains at the loci of HLX and STAT3 in addition to genes encoding both STAT3 regulators (AURKA, BCL3, JAK3, KPNB1, NAMPT, NFAT5, PIM3, ROCK1, SIX1, TPX2, WWOX) and targets (BATF3, IRF4, miR135b, miR21, RORC). Transcriptome data of ALCL cell lines showed absence of STAT3 mutations while MGA was mutated and downregulated, encoding a novel potential STAT3 repressor. Furthermore, enhanced IL17F-signalling activated HLX while TGFbeta-signalling inhibited HHEX expression. Taken together, our data extend the scope of the NKL-code for ILCs and spotlight aberrant expression of NKL homeobox gene HLX in ALCL. HLX represents a direct target of ALCL hallmark factor STAT3 and deregulates cell survival and differentiation in this malignancy.
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http://dx.doi.org/10.18632/oncotarget.27683DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7456612PMC
August 2020

The LL-100 Cell Lines Panel: Tool for Molecular Leukemia-Lymphoma Research.

Int J Mol Sci 2020 Aug 13;21(16). Epub 2020 Aug 13.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany.

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.
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http://dx.doi.org/10.3390/ijms21165800DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7461097PMC
August 2020

-activating mutation: no reliable indicator for efficacy of methyltransferase inhibitors.

Leuk Lymphoma 2020 12 26;61(12):2885-2893. Epub 2020 Jul 26.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

gain of function mutations (EZH2) has been implicated in the pathogenesis of B-non-Hodgkin lymphoma. The EZH2-specific inhibitor GSK126 inhibits trimethylation of histone H3K27 and induces target gene expression. However, in 3/4 B-NHL lymphoma cell lines, GSK126 (400 nM) did not induce growth arrest. Only at high doses (10 µM), the inhibitor was effective as antiproliferative agent, comparably in , wild-type, and -negative cell lines, suggesting that at high concentrations, the antiproliferative effects of GSK126 are off-target effects. In sum, we could not confirm that B-NHL cell lines with show a higher sensitivity to GSK126 than wild-type cell lines do. Only 1/4 B-NHL cell lines tested (PFEIFFER) were sensitive to GSK126 (400 nM) inducing growth arrest. If these results can be translated to patients, they raise the question of whether the presence of activating mutations alone allows selection for targeted therapy with EZH2 inhibitors.
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http://dx.doi.org/10.1080/10428194.2020.1795155DOI Listing
December 2020

Genomic deregulation of PRMT5 supports growth and stress tolerance in chronic lymphocytic leukemia.

Sci Rep 2020 06 17;10(1):9775. Epub 2020 Jun 17.

Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Department of Human and Animal Cell Lines, Braunschweig, Germany.

Patients suffering from chronic lymphocytic leukemia (CLL) display highly diverse clinical courses ranging from indolent cases to aggressive disease, with genetic and epigenetic features resembling this diversity. Here, we developed a comprehensive approach combining a variety of molecular and clinical data to pinpoint translocation events disrupting long-range chromatin interactions and causing cancer-relevant transcriptional deregulation. Thereby, we discovered a B cell specific cis-regulatory element restricting the expression of genes in the associated locus, including PRMT5 and DAD1, two factors with oncogenic potential. Experimental PRMT5 inhibition identified transcriptional programs similar to those in patients with differences in PRMT5 abundance, especially MYC-driven and stress response pathways. In turn, such inhibition impairs factors involved in DNA repair, sensitizing cells for apoptosis. Moreover, we show that artificial deletion of the regulatory element from its endogenous context resulted in upregulation of corresponding genes, including PRMT5. Furthermore, such disruption renders PRMT5 transcription vulnerable to additional stimuli and subsequently alters the expression of downstream PRMT5 targets. These studies provide a mechanism of PRMT5 deregulation in CLL and the molecular dependencies identified might have therapeutic implementations.
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http://dx.doi.org/10.1038/s41598-020-66224-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7299935PMC
June 2020

There is a Scientific Need for the Right Leukemia-Lymphoma Cell Lines.

Hemasphere 2019 Dec 31;3(6):e315. Epub 2019 Oct 31.

Leibniz-Institute DSMZ-German Collection of Microorganisms & Cell Cultures, Department of Human and Animal Cell Lines, Braunschweig, Germany.

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http://dx.doi.org/10.1097/HS9.0000000000000315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6924560PMC
December 2019

NKL homeobox gene activities in normal and malignant myeloid cells.

PLoS One 2019 11;14(12):e0226212. Epub 2019 Dec 11.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

Recently, we have documented a hematopoietic NKL-code mapping physiological expression patterns of NKL homeobox genes in early hematopoiesis and in lymphopoiesis, which spotlights genes deregulated in lymphoid malignancies. Here, we enlarge this map to include normal NKL homeobox gene expressions in myelopoiesis by analyzing public expression profiling data and primary samples from developing and mature myeloid cells. We thus uncovered differential activities of six NKL homeobox genes, namely DLX2, HHEX, HLX, HMX1, NKX3-1 and VENTX. We further examined public expression profiling data of 251 acute myeloid leukemia (AML) and 183 myelodysplastic syndrome (MDS) patients, thereby identifying 24 deregulated genes. These results revealed frequent deregulation of NKL homeobox genes in myeloid malignancies. For detailed analysis we focused on NKL homeobox gene NANOG, which acts as a stem cell factor and is correspondingly expressed alone in hematopoietic progenitor cells. We detected aberrant expression of NANOG in a small subset of AML patients and in AML cell line NOMO-1, which served as a model. Karyotyping and genomic profiling discounted rearrangements of the NANOG locus at 12p13. But gene expression analyses of AML patients and AML cell lines after knockdown and overexpression of NANOG revealed regulators and target genes. Accordingly, NKL homeobox genes HHEX, DLX5 and DLX6, stem cell factors STAT3 and TET2, and the NOTCH-pathway were located upstream of NANOG while NKL homeobox genes HLX and VENTX, transcription factors KLF4 and MYB, and anti-apoptosis-factor MIR17HG represented target genes. In conclusion, we have extended the NKL-code to the myeloid lineage and thus identified several NKL homeobox genes deregulated in AML and MDS. These data indicate a common oncogenic role of NKL homeobox genes in both lymphoid and myeloid malignancies. For misexpressed NANOG we identified an aberrant regulatory network, which contributes to the understanding of the oncogenic activity of NKL homeobox genes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0226212PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6905564PMC
March 2020

Deregulated NKL Homeobox Genes in B-Cell Lymphoma.

Cancers (Basel) 2019 Nov 26;11(12). Epub 2019 Nov 26.

Leibniz-Institute DSMZ, Department of Human and Animal Cell Lines, 38124 Braunschweig, Germany.

Recently, we have described physiological expression patterns of NKL homeobox genes in early hematopoiesis and in subsequent lymphopoiesis. We identified nine genes which constitute the so-called NKL-code. Aberrant overexpression of code-members or ectopically activated non-code NKL homeobox genes are described in T-cell leukemia and in T- and B-cell lymphoma, highlighting their oncogenic role in lymphoid malignancies. Here, we introduce the NKL-code in normal hematopoiesis and focus on deregulated NKL homeobox genes in B-cell lymphoma, including , and in Hodgkin lymphoma; and in diffuse large B-cell lymphoma; and in splenic marginal zone lymphoma. Thus, the roles of various members of the NKL homeobox gene subclass are considered in normal and pathological hematopoiesis in detail.
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http://dx.doi.org/10.3390/cancers11121874DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966443PMC
November 2019

DNMT3A R882H mutation in acute myeloid leukemia cell line SET-2.

Leuk Res 2020 01 9;88:106270. Epub 2019 Nov 9.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

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http://dx.doi.org/10.1016/j.leukres.2019.106270DOI Listing
January 2020

Small molecular modulators of JMJD1C preferentially inhibit growth of leukemia cells.

Int J Cancer 2020 01 25;146(2):400-412. Epub 2019 Jul 25.

Laboratory for Stem Cell and Regenerative Medicine, The Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China.

Histone demethylases are promising therapeutic targets as they play fundamental roles for survival of Mixed lineage leukemia rearranged acute leukemia (MLLr AL). Here we focused on the catalytic Jumonji domain of histone H3 lysine 9 (H3K9) demethylase JMJD1C to screen for potential small molecular modulators from 149,519 natural products and 33,765 Chinese medicine components via virtual screening. JMJD1C Jumonji domain inhibitor 4 (JDI-4) and JDI-12 that share a common structural backbone were detected within the top 15 compounds. Surface plasmon resonance analysis showed that JDI-4 and JDI-12 bind to JMJD1C and its family homolog KDM3B with modest affinity. In vitro demethylation assays showed that JDI-4 can reverse the H3K9 demethylation conferred by KDM3B. In vivo demethylation assays indicated that JDI-4 and JDI-12 could induce the global increase of H3K9 methylation. Cell proliferation and colony formation assays documented that JDI-4 and JDI-12 kill MLLr AL and other malignant hematopoietic cells, but not leukemia cells resistant to JMJD1C depletion or cord blood cells. Furthermore, JDI-16, among multiple compounds structurally akin to JDI-4/JDI-12, exhibits superior killing activities against malignant hematopoietic cells compared to JDI-4/JDI-12. Mechanistically, JDI-16 not only induces apoptosis but also differentiation of MLLr AL cells. RNA sequencing and quantitative PCR showed that JDI-16 induced gene expression associated with cell metabolism; targeted metabolomics revealed that JDI-16 downregulates lactic acids, NADP and other metabolites. Moreover, JDI-16 collaborates with all-trans retinoic acid to repress MLLr AML cells. In summary, we identified bona fide JMJD1C inhibitors that induce preferential death of MLLr AL cells.
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http://dx.doi.org/10.1002/ijc.32552DOI Listing
January 2020

The LL-100 panel: 100 cell lines for blood cancer studies.

Sci Rep 2019 06 3;9(1):8218. Epub 2019 Jun 3.

Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Department of Human and Animal Cell Lines, Braunschweig, Germany.

For many years, immortalized cell lines have been used as model systems for cancer research. Cell line panels were established for basic research and drug development, but did not cover the full spectrum of leukemia and lymphoma. Therefore, we now developed a novel panel (LL-100), 100 cell lines covering 22 entities of human leukemia and lymphoma including T-cell, B-cell and myeloid malignancies. Importantly, all cell lines are unequivocally authenticated and assigned to the correct tissue. Cell line samples were proven to be free of mycoplasma and non-inherent virus contamination. Whole exome sequencing and RNA-sequencing of the 100 cell lines were conducted with a uniform methodology to complement existing data on these publicly available cell lines. We show that such comprehensive sequencing data can be used to find lymphoma-subtype-characteristic copy number aberrations, mRNA isoforms, transcription factor activities and expression patterns of NKL homeobox genes. These exemplary studies confirm that the novel LL-100 panel will be useful for understanding the function of oncogenes and tumor suppressor genes and to develop targeted therapies.
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http://dx.doi.org/10.1038/s41598-019-44491-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547646PMC
June 2019

Deregulated expression of NKL homeobox genes in T-cell lymphomas.

Oncotarget 2019 May 14;10(35):3227-3247. Epub 2019 May 14.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

Recently, we have presented a scheme, termed "NKL-code", which describes physiological expression patterns of NKL homeobox genes in early hematopoiesis and in lymphopoiesis including main stages of T-, B- and NK-cell development. Aberrant activity of these genes underlies the generation of hematological malignancies notably T-cell leukemia. Here, we searched for deregulated NKL homeobox genes in main entities of T-cell lymphomas comprising angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell lymphoma (ALCL), adult T-cell leukemia/lymphoma (ATLL), hepatosplenic T-cell lymphoma (HSTL), NK/T-cell lymphoma (NKTL) and peripheral T-cell lymphoma (PTCL). Our data revealed altogether 19 aberrantly overexpressed genes in these types, demonstrating deregulated NKL homeobox genes involvement in T-cell lymphomas as well. For detailed analysis we focused on NKL homeobox gene MSX1 which is normally expressed in NK-cells. MSX1 was overexpressed in subsets of HSTL patients and HSTL-derived sister cell lines DERL-2 and DERL-7 which served as models to characterize mechanisms of deregulation. We performed karyotyping, genomic and expression profiling, and whole genome sequencing to reveal mutated and deregulated gene candidates, including the fusion gene CD53-PDGFRB. Subsequent knockdown experiments allowed the reconstruction of an aberrant network involved in MSX1 deregulation, including chromatin factors AUTS2 and mutated histone HIST1H3B(K27M). The gene encoding AUTS2 is located at chromosome 7q11 and may represent a basic target of the HSTL hallmark aberration i(7q). Taken together, our findings highlight an oncogenic role for deregulated NKL homeobox genes in T-cell lymphoma and identify MSX1 as a novel player in HSTL, implicated in aberrant NK- and T-cell differentiation.
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http://dx.doi.org/10.18632/oncotarget.26929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524933PMC
May 2019

Epstein-Barr virus (EBV) activates NKL homeobox gene HLX in DLBCL.

PLoS One 2019 29;14(5):e0216898. Epub 2019 May 29.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

NKL homeobox genes encode developmental transcription factors regulating basic processes in cell differentiation. According to their physiological expression pattern in early hematopoiesis and lymphopoiesis, particular members of this homeobox gene subclass constitute an NKL-code. B-cell specific NKL-code genes generate a regulatory network and their deregulation is implicated in B-cell lymphomagenesis. Epstein-Barr virus (EBV) infects B-cells and influences the activity of signalling pathways including JAK/STAT and several genes encoding developmental regulators. Therefore, EBV-infection impacts the pathogenesis and the outcome of B-cell malignancies including Hodgkin lymphoma and diffuse large B-cell lymphoma (DLBCL). Here, we isolated EBV-positive and EBV-negative subclones from the DLBCL derived cell line DOHH-2. These subclones served as models to investigate the role of EBV in deregulation of the B-cell specific NKL-code members HHEX, HLX, MSX1 and NKX6-3. We showed that the EBV-encoded factors LMP1 and LMP2A activated the expression of HLX via STAT3. HLX in turn repressed NKX6-3, SPIB and IL4R which normally mediate plasma cell differentiation. In addition, HLX repressed the pro-apoptotic factor BCL2L11/BIM and hence supported cell survival. Thus, EBV aberrantly activated HLX in DLBCL, thereby disturbing both B-cell differentiation and apoptosis. The results of our study appreciate the pathogenic role of EBV in NKL homeobox gene deregulation and B-cell malignancies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216898PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541347PMC
January 2020

NKL homeobox gene NKX2-2 is aberrantly expressed in Hodgkin lymphoma.

Oncotarget 2018 Dec 25;9(101):37480-37496. Epub 2018 Dec 25.

Department of Human and Animal Cell Lines, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

NKL homeobox genes encode basic transcriptional regulators of cell and tissue differentiation. Recently, we described a hematopoietic NKL-code comprising nine specific NKL homeobox genes expressed in normal hematopoietic stem cells, lymphoid progenitors and during lymphopoiesis, highlighting their physiological role in the development of T-, B- and NK-cells. Here, we identified aberrant expression of the non-hematopoietic neural NKL homeobox gene NKX2-2 in about 12% of both, classical Hodgkin lymphoma (HL) and nodular lymphocyte predominant (NLP) HL patients. The NKX2-2 expressing NLPHL-derived cell line DEV served as a model by analysing chromosomal configurations and expression profiling data to reveal activating mechanisms and downstream targets of this developmental regulator. While excluding chromosomal rearrangements at the locus of NKX2-2 we identified t(3;14)(p21;q32) resulting in overexpression of the IL17 receptor gene IL17RB via juxtaposition with the IGH-locus. SiRNA-mediated knockdown experiments demonstrated that IL17RB activated NKX2-2 transcription. Overexpression of IL17RB-cofactor DAZAP2 via chromosomal gain of 12q13 and deletion of its proteasomal inhibitor SMURF2 at 17q24 supported expression of NKX2-2. IL17RB activated transcription factors FLI1 and FOXG1 which in turn mediated NKX2-2 expression. In addition, overexpressed chromatin-modulator AUTS2 contributed to NKX2-2 activation as well. Downstream analyses indicated that NKX2-2 inhibits transcription of lymphoid NKL homeobox gene MSX1 and activates expression of basic helix-loop-helix factor NEUROD1 which may disturb B-cell differentiation processes via reported interaction with TCF3/E2A. Taken together, our data reveal ectopic activation of a neural gene network in HL placing NKX2-2 at its hub, highlighting a novel oncogenic impact of NKL homeobox genes in B-cell malignancies.
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http://dx.doi.org/10.18632/oncotarget.26459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331023PMC
December 2018

Screening human cell lines for viral infections applying RNA-Seq data analysis.

PLoS One 2019 10;14(1):e0210404. Epub 2019 Jan 10.

Department of Human and Animal Cell Lines, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

Monitoring viral infections of cell cultures is largely neglected although the viruses may have an impact on the physiology of cells and may constitute a biohazard regarding laboratory safety and safety of bioactive agents produced by cell cultures. PCR, immunological assays, and enzyme activity tests represent common methods to detect virus infections. We have screened more than 300 Cancer Cell Line Encyclopedia RNA sequencing and 60 whole exome sequencing human cell lines data sets for specific viral sequences and general viral nucleotide and protein sequence assessment applying the Taxonomer bioinformatics tool developed by IDbyDNA. The results were compared with our previous findings from virus specific PCR analyses. Both, the results obtained from the direct alignment method and the Taxonomer alignment method revealed a complete concordance with the PCR results: twenty cell lines were found to be infected with five virus species. Taxonomer further uncovered a bovine polyomavirus infection in the breast cancer cell line SK-BR-3 most likely introduced by contaminated fetal bovine serum. RNA-Seq data sets were more sensitive for virus detection although a significant proportion of cell lines revealed low numbers of virus specific alignments attributable to low level nucleotide contamination during RNA preparation or sequencing procedure. Low quality reads leading to Taxonomer false positive results can be eliminated by trimming the sequence data before analysis. One further important result is that no viruses were detected that had never been shown to occur in cell cultures. The results prove that the currently applied testing of cell cultures is adequate for the detection of contamination and for the risk assessment of cell cultures. The results emphasize that next generation sequencing is an efficient tool to determine the viral infection status of human cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0210404PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6328144PMC
October 2019

NKL homeobox gene activities in B-cell development and lymphomas.

PLoS One 2018 11;13(10):e0205537. Epub 2018 Oct 11.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

Homeobox genes encode transcription factors which regulate basic processes in development and cell differentiation. Several members of the NKL subclass are deregulated in T-cell progenitors and support leukemogenesis. We have recently described particular expression patterns of nine NKL homeobox genes in early hematopoiesis and T-cell development. Here, we screened NKL homeobox gene activities in normal B-cell development and extended the NKL-code to include this lymphoid lineage. Analysis of public expression profiling datasets revealed that HHEX and NKX6-3 were the only members differentially active in naïve B-cells, germinal center B-cells, plasma cells and memory B-cells. Subsequent examination of different types of B-cell malignancies showed both aberrant overexpression of NKL-code members and ectopic activation of subclass members physiologically silent in lymphopoiesis including BARX2, DLX1, EMX2, NKX2-1, NKX2-2 and NKX3-2. Based on these findings we performed detailed studies of the B-cell specific NKL homeobox gene NKX6-3 which showed enhanced activity in patient subsets of follicular lymphoma, mantle cell lymphoma and diffuse large B-cell lymphoma (DLBCL), and in three DLBCL cell lines to serve as in vitro models. While excluding genomic and chromosomal rearrangements at the locus of NKX6-3 (8p11) promoter studies demonstrated that B-cell factors MYB and PAX5 activated NKX6-3 transcription. Furthermore, aberrant BMP7/SMAD1-signalling and deregulated expression of chromatin complex components AUTS2 and PCGF5 promoted NKX6-3 activation. Finally, NKL homeobox genes HHEX, HLX, MSX1 and NKX6-3 were expressed in B-cell progenitors and generated a regulatory gene network in cell lines which we propose may provide physiological support for NKL-code formation in early B-cell development. Together, we identified an NKL-code in B-cell development whose violation may deregulate differentiation and promote malignant transformation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0205537PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181399PMC
April 2019

IG- neoplasms with precursor B-cell phenotype are molecularly distinct from Burkitt lymphomas.

Blood 2018 11 3;132(21):2280-2285. Epub 2018 Oct 3.

Department of Pediatric Hematology and Oncology and NHL-BFM Study Center, University Hospital Münster, Münster, Germany.

The notes instances of Burkitt lymphoma/leukemia (BL) with IG- rearrangement displaying a B-cell precursor immunophenotype (termed herein "preBLL"). To characterize the molecular pathogenesis of preBLL, we investigated 13 preBLL cases (including 1 cell line), of which 12 were analyzable using genome, exome, and targeted sequencing, imbalance mapping, and DNA methylation profiling. In 5 patients with reads across the IG- breakpoint junctions, we found evidence that the translocation derived from an aberrant VDJ recombination, as is typical for IG translocations arising in B-cell precursors. Genomic changes like biallelic IGH translocations or VDJ rearrangements combined with translocation into the VDJ region on the second allele, potentially preventing expression of a productive immunoglobulin, were detected in 6 of 13 cases. We did not detect mutations in genes frequently altered in BL, but instead found activating and/or mutations in 7 of 12 preBLLs. Gains on 1q, recurrent in BL and preB lymphoblastic leukemia/lymphoma (pB-ALL/LBL), were detected in 7 of 12 preBLLs. DNA methylation profiling showed preBLL to cluster with precursor B cells and pB-ALL/LBL, but apart from BL. We conclude that preBLL genetically and epigenetically resembles pB-ALL/LBL rather than BL. Therefore, we propose that preBLL be considered as a pB-ALL/LBL with recurrent genetic abnormalities.
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http://dx.doi.org/10.1182/blood-2018-03-842088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251006PMC
November 2018

RBFOX2 and alternative splicing in B-cell lymphoma.

Blood Cancer J 2018 08 10;8(8):77. Epub 2018 Aug 10.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

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http://dx.doi.org/10.1038/s41408-018-0114-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6086906PMC
August 2018

Aberrant activity of NKL homeobox gene NKX3-2 in a T-ALL subset.

PLoS One 2018 10;13(5):e0197194. Epub 2018 May 10.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

T-cell acute lymphoblastic leukemia (T-ALL) is a hematopoietic malignancy originating from T-cell progenitors in which differentiation is blocked at early stages. Physiological expression of specific NKL homeobox genes obeys a hematopoietic NKL-code implicated in the process of lymphopoiesis while in differentiated T-cells these genes are silenced. We propose that this developmental expression pattern underlies the observation that NKL homeobox genes are the most ubiquitous group of transcription factors deregulated in T-ALL, including TLX1, TLX3, NKX2-5 and NKX3-1. Here, we describe a novel member of the NKL homeobox gene subclass, NKX3-2 (BAPX1), which is aberrantly activated in 18% of pediatric T-ALL patients analyzed while being normally expressed in developing spleen. Identification of NKX3-2 expression in T-ALL cell line CCRF-CEM qualified these cells to model its deregulation and function in a leukemic context. Genomic and chromosomal analyses demonstrated normal configuration of the NKX3-2 locus at chromosome 4p15, thus excluding cytogenetic dysregulation. Comparative expression profiling analysis of NKX3-2 patient data revealed deregulated activity of BMP- and MAPK-signalling. These candidate pathways were experimentally confirmed to mediate aberrant NKX3-2 expression. We also show that homeobox gene SIX6, plus MIR17HG and GATA3 are downstream targets of NKX3-2 and plausibly contribute to the pathogenesis of this malignancy by suppressing T-cell differentiation. Finally, NKL homeobox gene NKX2-5 was activated by NKX3-2 in CCRF-CEM and by FOXG1 in PEER, representing mutually inhibitory activators of this translocated oncogene. Together, our findings reveal a novel oncogenic NKL homeobox gene subclass member which is aberrantly expressed in a large subset of T-ALL patients and participates in a deregulated gene network likely to arise in developing spleen.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197194PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5944955PMC
July 2018

Aberrant expression of NKL homeobox gene HLX in Hodgkin lymphoma.

Oncotarget 2018 Mar 16;9(18):14338-14353. Epub 2018 Feb 16.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.

NKL homeobox genes are basic regulators of cell and tissue differentiation, many acting as oncogenes in T-cell leukemia. Recently, we described an hematopoietic NKL-code comprising six particular NKL homeobox genes expressed in hematopoietic stem cells and lymphoid progenitors, unmasking their physiological roles in the development of these cell types. Hodgkin lymphoma (HL) is a B-cell malignancy showing aberrant activity of several developmental genes resulting in disturbed B-cell differentiation. To examine potential concordances in abnormal lymphoid differentiation of T- and B-cell malignancies we analyzed the expression of the hematopoietic NKL-code associated genes in HL, comprising HHEX, HLX, MSX1, NKX2-3, NKX3-1 and NKX6-3. Our approach revealed aberrant HLX activity in 8 % of classical HL patients and additionally in HL cell line L-540. Accordingly, to identify upstream regulators and downstream target genes of HLX we used L-540 cells as a model and performed chromosome and genome analyses, comparative expression profiling and functional assays via knockdown and overexpression experiments therein. These investigations excluded chromosomal rearrangements of the HLX locus at 1q41 and demonstrated that STAT3 operated directly as transcriptional activator of the HLX gene. Moreover, subcellular analyses showed highly enriched STAT3 protein in the nucleus of L-540 cells which underwent cytoplasmic translocation by repressing deacetylation. Finally, HLX inhibited transcription of B-cell differentiation factors MSX1, BCL11A and SPIB and of pro-apoptotic factor BCL2L11/BIM, thereby suppressing Etoposide-induced cell death. Collectively, we propose that aberrantly expressed NKL homeobox gene HLX is part of a pathological gene network in HL, driving deregulated B-cell differentiation and survival.
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http://dx.doi.org/10.18632/oncotarget.24512DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5865674PMC
March 2018

Hodgkin lymphoma cell lines: to separate the wheat from the chaff.

Biol Chem 2018 05;399(6):511-523

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstr. 7B, D-38124 Braunschweig, Germany.

Characteristic components of Hodgkin lymphoma (HL) tissue are the mono- or multinucleated Hodgkin-Reed-Sternberg (HRS) cells. Given the challenges of isolating these rare malignant cells and the difficulty in culturing cells from patients, many investigators have tried to establish cell lines in efforts to develop cellular tools for in vitro studies. A limited number of HL cell lines exist and have provided valuable insights into HL pathobiology. A literature survey indicated that 35 cell lines derived from HL patients have been published. To determine whether all these alleged HL cell lines hold up to scrutiny, we examined the available data and also put some of these cell lines to the test of hierarchical clustering, providing additional information regarding assignment to cell line type and tissue derivation. Hierarchical clustering separated the bona fide (classical) HL cell lines completely from cell lines derived from other lymphoma categories and proved conclusively that HL cell lines represent a distinct entity, irrespective of the cellular origin of the HRS cells. We conclude by pointing out the need for an intensified search for new cell culture avenues in order to develop a new generation of informative HL cell lines covering more widely the spectrum of HL stages and subtypes.
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http://dx.doi.org/10.1515/hsz-2017-0321DOI Listing
May 2018

MiR-130a is aberrantly overexpressed in adult acute myeloid leukemia with t(8;21) and its suppression induces AML cell death.

Ups J Med Sci 2018 Mar 1;123(1):19-27. Epub 2018 Mar 1.

a Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University , Suzhou , People's Republic of China.

Background: Emerging evidence has revealed that miRNAs can function as oncogenes or tumor suppressor genes in leukemia. The ectopic expression of miR-130a has been reported in chronic leukemia, but our understanding of the biological implications of miR-130a expression remains incomplete.

Methods: We quantified a cohort of de novo acute myeloid leukemia (AML) by bead-based miRNA and real-time quantitative PCR (Rq-PCR). The luciferase reporter gene assay was analyzed after the plasmid constructs which contain 5'-UTR of miR-130a and a Renilla luciferase reporter plasmid were transfected simultaneously into 293T cells. MTT and caspase 3/7 apoptosis assays were used to test cell viability and apoptosis.

Results: We identified miR-130a as significantly overexpressed in t(8;21) AML. Expression of miR-130a decreased significantly once patients with t(8;21) achieved complete remission, but increased sharply at the time of relapse. In patients with t(8;21) AML, KIT mutational status was associated with miR-130a expression-with higher expression associated with KIT activating mutations. Increased miR-130a expression in t(8;21) AML was associated with slightly worse event-free survival; however, no impact on overall survival was observed. Knockdown of AML1/ETO protein in the SKNO-1 cell line resulted in decrease of expression of miR-130a. Direct binding of AML1/ETO fusion protein with the promoter sequence of miR-130a was detected with luciferase reporter gene assay. Following miR-130a knockdown, SKNO-1 demonstrated increased sensitivity to etoposide.

Conclusions: Our data suggest that miR-130a is directly activated by AML1/ETO, and may act as a factor which is associated with leukemia burden, event-free survival, and chemotherapy sensitivity in t(8;21) AML.
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http://dx.doi.org/10.1080/03009734.2018.1440037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5901465PMC
March 2018

A new ETV6-NTRK3 cell line model reveals MALAT1 as a novel therapeutic target - a short report.

Cell Oncol (Dordr) 2018 Feb 8;41(1):93-101. Epub 2017 Nov 8.

Department of Human and Animal Cell Lines, DSMZ - German Collection of Microorganisms and Cell Cultures, Inhoffenstrasse 7b, 38124, Braunschweig, Germany.

Background: Previously, the chromosomal translocation t(12;15)(p13;q25) has been found to recurrently occur in both solid tumors and leukemias. This translocation leads to ETV6-NTRK3 (EN) gene fusions resulting in ectopic expression of the NTRK3 neurotropic tyrosine receptor kinase moiety as well as oligomerization through the donated ETV6-sterile alpha motif domain. As yet, no in vitro cell line model carrying this anomaly is available. Here we genetically characterized the acute promyelocytic leukemia (APL) cell line AP-1060 and, by doing so, revealed the presence of a t(12;15)(p13;q25). Subsequently, we evaluated its suitability as a model for this important clinical entity.

Methods: Spectral karyotyping, fluorescence in situ hybridization (FISH), and genomic and transcriptomic microarray-based profiling were used to screen for the presence of EN fusions. qRT-PCR was used for quantitative expression analyses. Responses to AZ-23 (NTRK) and wortmannin (PI3K) inhibitors, as well as to arsenic trioxide (ATO), were assessed using colorimetric assays. An AZ-23 microarray screen was used to define the EN targetome, which was parsed bioinformatically. MAPK1 and MALAT1 activation were assayed using Western blotting and RNA-FISH, respectively, whereas an AML patient cohort was used to assess the clinical occurrence of MALAT1 activation.

Results: An EN fusion was detected in AP1060 cells which, accordingly, turned out to be hypersensitive to AZ-23. We also found that AZ-23 can potentiate the effect of ATO and inhibit the phosphorylation of its canonical target MAPK1. The AZ-23 microarray screen highlighted a novel EN target, MALAT1, which also proved sensitive to wortmannin. Finally, we found that MALAT1 was massively up-regulated in a subset of AML patients.

Conclusions: From our data we conclude that AP-1060 may serve as a first publicly available preclinical model for EN. In addition, we conclude that these EN-positive cells are sensitive to the NTRK inhibitor AZ-23 and that this inhibitor may potentiate the therapeutic efficacy of ATO. Our data also highlight a novel AML EN target, MALAT1, which was so far only conspicuous in solid tumors.
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http://dx.doi.org/10.1007/s13402-017-0356-2DOI Listing
February 2018

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

Oncotarget 2017 Sep 21;8(40):66815-66832. Epub 2017 Jun 21.

Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ, Braunschweig, Germany.

NKL homeobox gene MSX1 is physiologically expressed in lymphoid progenitors and subsequently downregulated in developing T- and B-cells. In contrast, elevated expression levels of MSX1 persist in mature natural killer (NK)-cells, indicating a functional role in this compartment. While T-cell acute lymphoblastic leukemia (T-ALL) subsets exhibit aberrant overexpression of MSX1, we show here that in malignant NK-cells the level of MSX1 transcripts is aberrantly downregulated. Chromosomal deletions at 4p16 hosting the MSX1 locus have been described in NK-cell leukemia patients. However, NK-cell lines analyzed here showed normal MSX1 gene configurations, indicating that this aberration might be uncommon. To identify alternative MSX1 regulatory mechanisms we compared expression profiling data of primary normal NK-cells and malignant NK-cell lines. This procedure revealed several deregulated genes including overexpressed IRF4, MIR155HG and MIR17HG and downregulated AUTS2, EP300, GATA3 and HHEX. As shown recently, chromatin-modulator AUTS2 is overexpressed in T-ALL subsets where it mediates aberrant transcriptional activation of MSX1. Here, our data demonstrate that in malignant NK-cell lines AUTS2 performed MSX1 activation as well, but in accordance with downregulated MSX1 transcription therein we detected reduced AUTS2 expression, a small genomic deletion at 7q11 removing exons 3 and 4, and truncating mutations in exon 1. Moreover, genomic profiling and chromosomal analyses of NK-cell lines demonstrated amplification of IRF4 at 6p25 and deletion of PRDM1 at 6q21, highlighting their potential oncogenic impact. Functional analyses performed via knockdown or forced expression of these genes revealed regulatory network disturbances effecting downregulation of MSX1 which may underlie malignant development in NK-cells.
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http://dx.doi.org/10.18632/oncotarget.18609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5620138PMC
September 2017
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