The notch pathway promotes NF-κB activation through Asb2 in T cell acute lymphoblastic leukemia cells

Cell Mol Biol Lett. 2018 Aug 9;23:37. doi: 10.1186/s11658-018-0102-4. eCollection 2018.

Abstract

Background: Oncogenic Notch1 is known to activate the NF-κB pathway in T cell acute lymphoblastic leukemia (T-ALL) and to up-regulate the transcription of Asb2α, a specificity factor for an E3 ubiquitin ligase complex that plays an important role in hematopoietic differentiation. Therefore, we hypothesize that Notch1 might regulate the NF-κB pathway through Asb2α.

Methods: The study involved down-regulation of Notch1 in T-ALL cell lines (CCRF-CEM cells and MOLT-4 cells) through treatment with gamma-secretase inhibitor (GSI) as well as the modulation of Asb2 in CCRF-CEM cells and MOLT-4 cells through transduction with lentivirus carrying Asb2 or Asb2-shRNA. Experiments using real-time PCR, western blot and co-immunoprecipitation were performed to evaluate the expression levels of related genes. Cell proliferation and apoptosis were measured while the expression of Asb2 was enhanced or inhibited.

Results: Here, we demonstrated for the first time that Notch1 can activate the transcription of Asb2α, which then stimulates activation of NF-κB in T-ALL cells. Asb2α exerts its effects by inducing degradation and dissociation of IκBα from NF-κB in T-ALL cells. Moreover, specific suppression of Asb2α expression can promote apoptosis and inhibit proliferation of T-ALL cells.

Conclusion: Notch1 modulates the NF-κB pathway through Asb2α, indicating that Asb2α inhibition is a promising option for targeted therapy against T-ALL.

Keywords: Asb2; NF-κB; Notch1; T cell acute lymphoblastic leukemia.

MeSH terms

  • Apoptosis
  • Cell Line, Tumor
  • Cell Proliferation
  • Humans
  • NF-kappa B / immunology*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / genetics
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / immunology*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / pathology
  • Receptors, Notch / immunology*
  • Signal Transduction*
  • Suppressor of Cytokine Signaling Proteins / genetics
  • Suppressor of Cytokine Signaling Proteins / immunology*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / pathology
  • Transcriptional Activation

Substances

  • ASB2 protein, human
  • NF-kappa B
  • Receptors, Notch
  • Suppressor of Cytokine Signaling Proteins