title: Identification of novel target genes of nerve growth factor (NGF) in human mastocytoma cell line (HMC-1 (V560G c-Kit)) by transcriptome analysis.
abstract: BACKGROUND
  Nerve growth factor (NGF) is a potent growth factor that plays a key role in neuronal cell differentiation and may also play a role in hematopoietic differentiation. It has been shown that NGF induced synergistic action for the colony formation of CD34 positive hematopoietic progenitor cells treated with macrophage-colony stimulating factor (M-CSF or CSF-1), or stem cell factor (SCF). However, the exact role of NGF in hematopoietic system is unclear. It is also not clear whether NGF mediated signals in hematopoietic cells are identical to those in neuronal cells.
  
  
  RESULTS
  To study the signal transduction pathways induced by NGF treatment in hematopoietic cells, we utilized the mastocytoma cell line HMC-1(V560G c-Kit) which expresses the NGF receptor, tropomyosin-receptor-kinase (Trk)A, as well as the constitutively activated SCF receptor, V560G c-Kit, which can be inhibited completely by treatment with the potent tyrosine kinase inhibitor imatinib mesylate (imatinib). NGF rescues HMC-1(V560G c-Kit) cells from imatinib mediated cell death and promotes proliferation. To examine the NGF mediated proliferation and survival in these cells, we compared the NGF mediated upregulated genes (30 and 120 min after stimulation) to the downregulated genes by imatinib treatment (downregulation of c-Kit activity for 4 h) by transcriptome analysis. The following conclusions can be drawn from the microarray data: Firstly, gene expression profiling reveals 50% overlap of genes induced by NGF-TrkA with genes expressed downstream of V560G c-Kit. Secondly, NGF treatment does not enhance expression of genes involved in immune related functions that were down regulated by imatinib treatment. Thirdly, more than 55% of common upregulated genes are involved in cell proliferation and survival. Fourthly, we found Kruppel-like factor (KLF) 2 and Smad family member 7 (SMAD7) as the NGF mediated novel downstream genes in hematopoietic cells. Finally, the downregulation of KLF2 gene enhanced imatinib induced apoptosis.
  
  
  CONCLUSIONS
  NGF does not induce genes which are involved in immune related functions, but induces proliferation and survival signals in HMC-1(V560G c-Kit) cells. Furthermore, the current data provide novel candidate genes, KLF2 and SMAD7 which are induced by NGF/TrkA activation in hematopoietic cells. Since the depletion of KLF2 causes enhanced apoptosis of HMC-1(V560G c-Kit), KLF2 may play a role in the NGF mediated survival signal.
authors.affiliation: Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str, 1, D-30623 Hannover, Germany.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Dutta
authors.forename: Alexandra
authors.initials: A
authors.lastname: Koch
authors.forename: Bjoern
authors.initials: B
authors.lastname: Breyer
authors.forename: Heike
authors.initials: H
authors.lastname: Schneider
authors.forename: Oliver
authors.initials: O
authors.lastname: Dittrich-Breiholz
authors.forename: Michael
authors.initials: M
authors.lastname: Kracht
authors.forename: Teruko
authors.initials: T
authors.lastname: Tamura
mesh_terms: D017209:Apoptosis; D001549:Benzamides; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D015536:Down-Regulation; D020869:Gene Expression Profiling; D006801:Humans; D000068877:Imatinib Mesylate; D051741:Kruppel-Like Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034801:Mastocytoma; D020932:Nerve Growth Factor / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D020800:Receptor, Nerve Growth Factor / Q000235:genetics / Q000378:metabolism; D020917:Receptor, trkA / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051906:Smad7 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D001549:Benzamides; C096161:KLF2 protein, human; D051741:Kruppel-Like Transcription Factors; D010879:Piperazines; D011743:Pyrimidines; D034741:RNA, Small Interfering; D020800:Receptor, Nerve Growth Factor; D051906:Smad7 Protein; D000068877:Imatinib Mesylate; D020932:Nerve Growth Factor; D011505:Protein-Tyrosine Kinases; D019009:Proto-Oncogene Proteins c-kit; D020917:Receptor, trkA