NKL homeobox gene activities in normal and malignant myeloid cells

PLoS One. 2019 Dec 11;14(12):e0226212. doi: 10.1371/journal.pone.0226212. eCollection 2019.

Abstract

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.

MeSH terms

  • Cell Line, Tumor
  • Cell Lineage
  • Gene Expression Regulation
  • Homeodomain Proteins / antagonists & inhibitors
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Humans
  • Karyotype
  • Kruppel-Like Factor 4
  • Leukemia, Myeloid / genetics*
  • Leukemia, Myeloid / metabolism
  • Leukemia, Myeloid / pathology
  • Myelodysplastic Syndromes / genetics*
  • Myelodysplastic Syndromes / metabolism
  • Myelodysplastic Syndromes / pathology
  • Myeloid Cells / cytology
  • Myeloid Cells / metabolism*
  • Nanog Homeobox Protein / antagonists & inhibitors
  • Nanog Homeobox Protein / genetics
  • Nanog Homeobox Protein / metabolism
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • STAT3 Transcription Factor / metabolism
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism

Substances

  • HHEX protein, human
  • HLX protein, human
  • Homeodomain Proteins
  • KLF4 protein, human
  • Kruppel-Like Factor 4
  • NKX3-1 protein, human
  • Nanog Homeobox Protein
  • RNA, Small Interfering
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Transcription Factors
  • VENTX protein, human

Grants and funding

Both contributing institutes, Leibniz-Institute DSMZ and Hannover Medical School, are owned by the government of Lower Saxony. They are non-profit and non-commercial institutes. The funder provided support in the form of salaries for authors [SN, MS, RAFM, CP, MK, CM, MK, ID, HGD], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.