Notch-1 regulates cell death independently of differentiation in murine erythroleukemia cells through multiple apoptosis and cell cycle pathways

J Cell Physiol. 2004 Jun;199(3):418-33. doi: 10.1002/jcp.10467.


Notch signaling is a potential therapeutic target for various solid and hematopoietic malignancies. We have recently shown that downregulation of Notch-1 expression has significant anti-neoplastic activity in pre-clinical models. However, the mechanisms through which Notch modulation may affect cell fate in cancer remain poorly understood. We had previously shown that Notch-1 prevents apoptosis and is necessary for pharmacologically induced differentiation in murine erythroleukemia (MEL) cells. We investigated the mechanisms of these effects using three experimental strategies: (1) MEL cells stably transfected with antisense Notch-1 or constitutively active Notch-1, (2) activation of Notch-1 by a cell-associated ligand, and (d3) activation of Notch-1 by a soluble peptide ligand. We show that: (1) downregulation of Notch-1 sensitizes MEL cells to apoptosis induced by a Ca(2+) influx or anti-neoplastic drugs; (2) Notch-1 downregulation induces phosphorylation of c-Jun N-terminal kinase (JNK) while constitutive activation of Notch-1 or prolonged exposure to a soluble Notch ligand abolishes it; (3) Notch-1 has dose- and time-dependent effects on the levels of apoptotic inhibitor Bcl-x(L) and cell cycle regulators p21(cip1/waf1), p27(kip1), and Rb; and (4) Notch-1 activation by a cell-associated ligand is accompanied by rapid and transient induction of NF-kappaB DNA-binding activity. The relative effects of Notch-1 signaling on these pathways depend on the levels of Notch-1 expression, the mechanism of activation, and the timing of activation. The relevance of these findings to the role of Notch signaling in differentiation and cancer are discussed.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Blotting, Western
  • Cell Cycle / physiology*
  • Cell Cycle Proteins / metabolism
  • Cell Differentiation / physiology
  • Cells, Cultured
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclin-Dependent Kinase Inhibitor p27
  • Cyclins / metabolism
  • Down-Regulation
  • Electrophoretic Mobility Shift Assay
  • JNK Mitogen-Activated Protein Kinases
  • Leukemia, Erythroblastic, Acute / physiopathology
  • Mice
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Receptor, Notch1
  • Receptors, Cell Surface / physiology*
  • Signal Transduction / physiology*
  • Transcription Factors*
  • Transfection
  • Tumor Suppressor Proteins / metabolism
  • bcl-X Protein


  • Bcl2l1 protein, mouse
  • Cdkn1a protein, mouse
  • Cdkn1b protein, mouse
  • Cell Cycle Proteins
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Notch1 protein, mouse
  • Proto-Oncogene Proteins c-bcl-2
  • Receptor, Notch1
  • Receptors, Cell Surface
  • Transcription Factors
  • Tumor Suppressor Proteins
  • bcl-X Protein
  • Cyclin-Dependent Kinase Inhibitor p27
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases