Project description:Recently, we have reported a hematopoietic NKL-code which describes normal expression patterns of NKL homeobox genes in early hematopoiesis and lymphopoiesis including T-cell, B-cell and NK-cell development. This code allows the identification of deregulated NKL homeobox genes in lymphoid malignancies. Here, we report normal activities of NKL homeobox genes in myelopoiesis, thus, extending the NKL-code for the hematopoietic system. Analysis of public expression profiling data for developing and mature granulocytes, mast cells, monocytes, macrophages, megakaryocytes and erythrocytes revealed seven active myeloid NKL homeobox genes including DLX2, HHEX, HLX, HMX1, NANOG, NKX3-1 and VENTX. Furthermore, we analyzed public expression profiling data of 251 acute myeloid leukemia (AML) patients identifying 18 deregulated genes. These results indicated that NKL homeobox genes are frequently deregulated in this myeloid malignancy. For detailed analysis we focused on NKL homeobox gene NANOG which acts as stem cell factor and was accordingly expressed just in hematopoietic stem/progenitor cells. We detected aberrant NANOG expression in a small subset of AML patients and in AML cell line NOMO-1 which served as model to investigate upstream and downstream factors of this gene. Karyotyping and genomic profiling excluded rearrangements of the NANOG locus at 12p13. Analysis of NOMO-1 cells treated for NANOG knockdown, expression profiling analyses of HL-60 cells lentivirally transfected for NANOG overexpression, and of public AML patient data revealed regulators and target genes of NANOG. NKL homeobox genes HHEX and MSX1 and the NOTCH-pathway were located upstream of NANOG and HHEX, HLX, VENTX, MYB, CDK6, MAML2 and MIR17HG represented target genes of NANOG in the myeloid context. In conclusion, we described a myeloid NKL-code and several deregulated NKL homeobox genes in AML. We identified for NKL homeobox gene NANOG deregulating factors and downstream activities in AML. These data indicate a common oncogenic role of NKL homeobox genes in myeloid malignancies.
Project description:Homeobox genes encode transcription factors regulating basic processes in cell differentiation during embryogenesis and in the adult. Recently, we have reported the NKL-code which describes physiological expression patterns of nine NKL homeobox genes in early hematopoiesis and in lymphopoiesis including main stages of T-, B- and NK-cell development. Aberrant activity of NKL homeobox genes is involved in the generation of hematological malignancies including T-cell leukemia. Here, we searched for deregulated NKL homeobox genes in main entities of T-cell lymphomas comprising peripheral T-cell lymphoma (PTCL), angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell lymphoma (ALCL), adult T-cell leukemia/lymphoma (ATLL), hepatospleenic T-cell lymphoma (HSTL), and NK/T-cell lymphoma (NKTL). Our data revealed in all types altogether 19 aberrantly overexpressed genes, demonstrating that deregulated NKL homeobox genes play a significant role in T-cell lymphomas as well. For detailed analyses we focused on NKL homeobox gene MSX1 which is normally expressed in NK-cells and aberrantly activated in T-cell leukemia. This gene was overexpressed in subsets of HSTL patients and HSTL-derived sister cell lines DERL-2 and DERL-7 which served as models to identify mechanisms of deregulation. We performed genomic and expression profiling and whole genome sequencing and revealed mutated and deregulated gene candidates including the fusion gene CD53-PDGFRB exclusively expressed in DERL-2. Subsequent knockdown experiments allowed the construction of an aberrant network involved in MSX1 deregulation containing chromatin factors AUTS2 and H3B/H3.1, PDGF- and BMP-signalling pathways, and homeobox genes NKX2-2 and PITX1. The gene encoding AUTS2 is located at 7q11 and may represent a basic target of the HSTL hallmark aberration i(7q). Our data indicate both oncogenic and tumor suppressor functions of MSX1 in HSTL, reflecting its activity in early lineage differentiation of T- and NK-cells and the presence of NK-cell like characteristics in malignant HSTL cells. In this context, NKL homeobox gene MSX1 may represent a selective target in HSTL tumor evolution. Together, the data highlight an oncogenic role of deregulated NKL homeobox genes in T-cell lymphoma and identified MSX1 as a novel player in HSTL, involved in aberrant NK- and T-cell differentiation.
Project description:Homeobox genes encode transcription factors regulating basic processes in cell differentiation during embryogenesis and in the adult. Recently, we have reported the NKL-code which describes physiological expression patterns of nine NKL homeobox genes in early hematopoiesis and in lymphopoiesis including main stages of T-, B- and NK-cell development. Aberrant activity of NKL homeobox genes is involved in the generation of hematological malignancies including T-cell leukemia. Here, we searched for deregulated NKL homeobox genes in main entities of T-cell lymphomas comprising peripheral T-cell lymphoma (PTCL), angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell lymphoma (ALCL), adult T-cell leukemia/lymphoma (ATLL), hepatospleenic T-cell lymphoma (HSTL), and NK/T-cell lymphoma (NKTL). Our data revealed in all types altogether 19 aberrantly overexpressed genes, demonstrating that deregulated NKL homeobox genes play a significant role in T-cell lymphomas as well. For detailed analyses we focused on NKL homeobox gene MSX1 which is normally expressed in NK-cells and aberrantly activated in T-cell leukemia. This gene was overexpressed in subsets of HSTL patients and HSTL-derived sister cell lines DERL-2 and DERL-7 which served as models to identify mechanisms of deregulation. We performed genomic and expression profiling and whole genome sequencing and revealed mutated and deregulated gene candidates including the fusion gene CD53-PDGFRB exclusively expressed in DERL-2. Subsequent knockdown experiments allowed the construction of an aberrant network involved in MSX1 deregulation containing chromatin factors AUTS2 and H3B/H3.1, PDGF- and BMP-signalling pathways, and homeobox genes NKX2-2 and PITX1. The gene encoding AUTS2 is located at 7q11 and may represent a basic target of the HSTL hallmark aberration i(7q). Our data indicate both oncogenic and tumor suppressor functions of MSX1 in HSTL, reflecting its activity in early lineage differentiation of T- and NK-cells and the presence of NK-cell like characteristics in malignant HSTL cells. In this context, NKL homeobox gene MSX1 may represent a selective target in HSTL tumor evolution. Together, the data highlight an oncogenic role of deregulated NKL homeobox genes in T-cell lymphoma and identified MSX1 as a novel player in HSTL, involved in aberrant NK- and T-cell differentiation.
Project description:NKL homeobox genes encode transcription factors which impact normal development and hematopoietic malignancies if deregulated. Recently, we established a NKL-code which describes the physiological expression pattern of eleven NKL homeobox genes in the course of hematopoiesis, allowing evaluation of aberrantly activated NKL-genes in leukemia/lymphoma. Here, we identify ectopic expression of NKL homeobox gene NKX2-4 in erythroblastic acute myeloid leukemia (AML) cell line OCI-M2 and describe investigation of its activating factors and target genes. Comparative expression profiling data of AML cell lines revealed in OCI-M2 an aberrantly activated program for endothelial development including master factor ETV2 and the additional endothelial signature genes HEY1, IRF6 and SOX7. SiRNA-mediated knockdown experiments showed their role in activating NKX2-4 expression. Furthermore, the ETV2 locus at 19p13 was genomically amplified, possibly underlying its aberrant expression. Target gene analyses of NKX2-4 revealed activated ETV2, HEY1 and SIX5, and suppressed FLI1. Comparative expression profiling analysis of public datasets for AML patients and primary megakaryocyte-erythroid progenitor cells showed conspicuous similarities to NKX2-4 activating factors and target genes we identified, supporting the clinical relevance of our findings and developmental disturbance by NKX2-4. Finally, identification and target gene analysis of aberrantly expressed NKX2-3 in AML patients and megakaryoblastic AML cell line ELF-153 showed activation of FLI1, contrasting with OCI-M2. FLI1 encodes a master factor for myelopoiesis, driving megakaryocytic and suppressing erythroid differentiation, thus representing a basic developmental target of these homeo-oncogenes. Taken together, we have identified aberrantly activated NKL homeobox genes NKX2-3 and NKX2-4 in AML, deregulating megakaryocytic and erythroid differentiation processes, and thereby driving formation specific AML subtypes.
Project description:NKL homeobox genes encode basic transcriptional regulators of cell and tissue differentiation. Recently, we described a hematopoietic NKL-code comprising particular NKL homeobox genes expressed in normal hematopoietic stem cells and during lymphopoiesis, highlighting their physiological role in the development of T-, B- and NK-cells. Here, we describe aberrant expression of the neural non-hematopoietic NKL homeobox gene NKX2-2 in 10% of both classical Hodgkin lymphoma (HL) and nodular lymphocyte predominant (NLP) HL patients. NKX2-2 expressing NLPHL 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;q34) resulting in overexpression of the IL17 receptor gene IL17RB via juxtaposition to 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. NKX2-2 inhibited transcription of lymphoid NKL homeobox gene MSX1 and activated 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 in HL ectopic activation of a neural gene network showing NKX2-2 at a central position, highlighting oncogenic impacts of NKL homeobox genes in B-cell malignancies.
Project description: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.
Project description:T-cell acute lymphoblastic leukemia (T-ALL) cells represent developmentally arrested T-cell progenitors, subsets of which aberrantly express homeobox genes of the NKL subclass, including TLX1, TLX3, NKX2-1, NKX2-5, NKX3-1 and MSX1. Here, we analyzed the transcriptional landscape of all 48 members of the NKL homeobox gene subclass in CD34+ hematopoietic stem cells (HSCs) and during lymphopoiesis, identifying activities of 9 particular genes. Four of these were expressed in HSCs (HHEX, HLX1, NKX2-3 and NKX3-1) and three in common lymphoid progenitors (HHEX, HLX1 and MSX1). Interestingly, our data indicated downregulation of NKL homeobox gene transcripts in late progenitors and mature T-cells, a phenomenon which might explain the oncogenic impact of this group of genes in T-ALL. Using MSX1-expressing T-ALL cell lines as models, we showed that HHEX activates while HLX1, NKX2-3 and NKX3-1 repress MSX1 transcription, demonstrating the mutual regulation and differential activities of these homeobox genes. Analysis of a public T-ALL expression profiling data set comprising 117 patient samples identified 20 aberrantly activated members of the NKL subclass, extending the number of known NKL homeobox oncogene candidates. While 7/20 genes were also active during hematopoiesis, the remaining 13 showed ectopic expression. Finally, comparative analyses of T-ALL patient and cell line profiling data of NKL-positive and NKL-negative samples indicated absence of common target genes but instead highlighted deregulation of apoptosis as common oncogenic effect. Taken together, we present a comprehensive survey of NKL homeobox genes in early hematopoiesis, T-cell development and T-ALL, showing that these genes generate an NKL-code for the diverse stages of lymphoid development which might be fundamental for regular differentiation.
Project description:Recently, we have 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 expressed additionally VENTX. The subsequent 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 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. Subsequent knockdown experiments and modulations of signalling pathways in MUTZ-3 and control cell lines, in addition to analysis of public chromatin immune-precipitation data 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 in 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 part of a cDC-specific gene regulatory network operating in DC differentiation and function.
Project description:Our study illustrates the leukemic role of deregulated NKL homeobox genes HMX2 and HMX3 revealing molecular mechanisms of differentiation arrest in AML.Whole genome sequencing of EOL-1 identified two mutations in the regulatory upstream regions of HMX2/3 resulting in the generation of a novel ETS-site and transformation of a former NFkB-site into an SP1-site.
Project description:NKL homeobox genes encode developmental transcription factors regulating basic processes in cell differentiation. According to their physiological expression pattern in early hematopoiesis and B-cell development, particular members of this homeobox gene subclass constitute an NKL-code. These B-cell specific 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 model 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 pro-apoptotic factor BCL2L11/BIM supporting cell survival. Thus, EBV aberrantly activated HLX thereby disturbing both B-cell differentiation and apoptosis in DLBCL. The results of our study contribute to better understand the pathogenic role of EBV in B-cell malignancies.