NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia: Evidence for a NOTCH1 mutation-driven epigenetic dysregulation

F. Pozzo, T. Bittolo, F. Arruga, Pietro Bulian, Paolo Macor, E. Tissino, B. Gizdic, Francesca M. Rossi, Riccardo Bomben, Antonella Zucchetto, Dania Benedetti, Massimo Degan, Giovanni D'Arena, Annalisa Chiarenza, Francesco Zaja, Gabriele Pozzato, Davide Rossi, Gianluca Gaidano, Giovanni Del Poeta, Silvia DeaglioValter Gattei, Michele Dal Bo

Research output: Contribution to journalArticle

Abstract

In chronic lymphocytic leukemia (CLL), NOTCH1 mutations have been associated with clinical resistance to the anti-CD20 rituximab, although the mechanisms behind this peculiar behavior remain to be clarified. In a wide CLL series (n=692), we demonstrated that CLL cells from NOTCH1-mutated cases (87/692) were characterized by lower CD20 expression and lower relative lysis induced by anti-CD20 exposure in vitro. Consistently, CD20 expression by CLL cells was upregulated in vitro by γ-secretase inhibitors or NOTCH1-specific small interfering RNA and the stable transfection of a mutated (c.7541-7542delCT) NOTCH1 intracellular domain (NICD-mut) into CLL-like cells resulted in a strong downregulation of both CD20 protein and transcript. By using these NICD-mut transfectants, we investigated protein interactions of RBPJ, a transcription factor acting either as activator or repressor of NOTCH1 pathway when respectively bound to NICD or histone deacetylases (HDACs). Compared with controls, NICD-mut transfectants had RBPJ preferentially complexed to NICD and showed higher levels of HDACs interacting with the promoter of the CD20 gene. Finally, treatment with the HDAC inhibitor valproic acid upregulated CD20 in both NICD-mut transfectants and primary CLL cells. In conclusion, NOTCH1 mutations are associated with low CD20 levels in CLL and are responsible for a dysregulation of HDAC-mediated epigenetic repression of CD20 expression.

Original languageEnglish
Pages (from-to)182-189
Number of pages8
JournalLeukemia
Volume30
Issue number1
DOIs
Publication statusPublished - Jan 1 2016

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B-Cell Chronic Lymphocytic Leukemia
Epigenomics
Histone Deacetylases
Mutation
Epigenetic Repression
Amyloid Precursor Protein Secretases
Valproic Acid
Small Interfering RNA
Transfection
Proteins
Transcription Factors
Down-Regulation
Genes

ASJC Scopus subject areas

  • Hematology
  • Cancer Research
  • Anesthesiology and Pain Medicine

Cite this

NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia : Evidence for a NOTCH1 mutation-driven epigenetic dysregulation. / Pozzo, F.; Bittolo, T.; Arruga, F.; Bulian, Pietro; Macor, Paolo; Tissino, E.; Gizdic, B.; Rossi, Francesca M.; Bomben, Riccardo; Zucchetto, Antonella; Benedetti, Dania; Degan, Massimo; D'Arena, Giovanni; Chiarenza, Annalisa; Zaja, Francesco; Pozzato, Gabriele; Rossi, Davide; Gaidano, Gianluca; Del Poeta, Giovanni; Deaglio, Silvia; Gattei, Valter; Dal Bo, Michele.

In: Leukemia, Vol. 30, No. 1, 01.01.2016, p. 182-189.

Research output: Contribution to journalArticle

Pozzo, F, Bittolo, T, Arruga, F, Bulian, P, Macor, P, Tissino, E, Gizdic, B, Rossi, FM, Bomben, R, Zucchetto, A, Benedetti, D, Degan, M, D'Arena, G, Chiarenza, A, Zaja, F, Pozzato, G, Rossi, D, Gaidano, G, Del Poeta, G, Deaglio, S, Gattei, V & Dal Bo, M 2016, 'NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia: Evidence for a NOTCH1 mutation-driven epigenetic dysregulation', Leukemia, vol. 30, no. 1, pp. 182-189. https://doi.org/10.1038/leu.2015.182
Pozzo, F. ; Bittolo, T. ; Arruga, F. ; Bulian, Pietro ; Macor, Paolo ; Tissino, E. ; Gizdic, B. ; Rossi, Francesca M. ; Bomben, Riccardo ; Zucchetto, Antonella ; Benedetti, Dania ; Degan, Massimo ; D'Arena, Giovanni ; Chiarenza, Annalisa ; Zaja, Francesco ; Pozzato, Gabriele ; Rossi, Davide ; Gaidano, Gianluca ; Del Poeta, Giovanni ; Deaglio, Silvia ; Gattei, Valter ; Dal Bo, Michele. / NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia : Evidence for a NOTCH1 mutation-driven epigenetic dysregulation. In: Leukemia. 2016 ; Vol. 30, No. 1. pp. 182-189.
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abstract = "In chronic lymphocytic leukemia (CLL), NOTCH1 mutations have been associated with clinical resistance to the anti-CD20 rituximab, although the mechanisms behind this peculiar behavior remain to be clarified. In a wide CLL series (n=692), we demonstrated that CLL cells from NOTCH1-mutated cases (87/692) were characterized by lower CD20 expression and lower relative lysis induced by anti-CD20 exposure in vitro. Consistently, CD20 expression by CLL cells was upregulated in vitro by γ-secretase inhibitors or NOTCH1-specific small interfering RNA and the stable transfection of a mutated (c.7541-7542delCT) NOTCH1 intracellular domain (NICD-mut) into CLL-like cells resulted in a strong downregulation of both CD20 protein and transcript. By using these NICD-mut transfectants, we investigated protein interactions of RBPJ, a transcription factor acting either as activator or repressor of NOTCH1 pathway when respectively bound to NICD or histone deacetylases (HDACs). Compared with controls, NICD-mut transfectants had RBPJ preferentially complexed to NICD and showed higher levels of HDACs interacting with the promoter of the CD20 gene. Finally, treatment with the HDAC inhibitor valproic acid upregulated CD20 in both NICD-mut transfectants and primary CLL cells. In conclusion, NOTCH1 mutations are associated with low CD20 levels in CLL and are responsible for a dysregulation of HDAC-mediated epigenetic repression of CD20 expression.",
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T1 - NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia

T2 - Evidence for a NOTCH1 mutation-driven epigenetic dysregulation

AU - Pozzo, F.

AU - Bittolo, T.

AU - Arruga, F.

AU - Bulian, Pietro

AU - Macor, Paolo

AU - Tissino, E.

AU - Gizdic, B.

AU - Rossi, Francesca M.

AU - Bomben, Riccardo

AU - Zucchetto, Antonella

AU - Benedetti, Dania

AU - Degan, Massimo

AU - D'Arena, Giovanni

AU - Chiarenza, Annalisa

AU - Zaja, Francesco

AU - Pozzato, Gabriele

AU - Rossi, Davide

AU - Gaidano, Gianluca

AU - Del Poeta, Giovanni

AU - Deaglio, Silvia

AU - Gattei, Valter

AU - Dal Bo, Michele

PY - 2016/1/1

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N2 - In chronic lymphocytic leukemia (CLL), NOTCH1 mutations have been associated with clinical resistance to the anti-CD20 rituximab, although the mechanisms behind this peculiar behavior remain to be clarified. In a wide CLL series (n=692), we demonstrated that CLL cells from NOTCH1-mutated cases (87/692) were characterized by lower CD20 expression and lower relative lysis induced by anti-CD20 exposure in vitro. Consistently, CD20 expression by CLL cells was upregulated in vitro by γ-secretase inhibitors or NOTCH1-specific small interfering RNA and the stable transfection of a mutated (c.7541-7542delCT) NOTCH1 intracellular domain (NICD-mut) into CLL-like cells resulted in a strong downregulation of both CD20 protein and transcript. By using these NICD-mut transfectants, we investigated protein interactions of RBPJ, a transcription factor acting either as activator or repressor of NOTCH1 pathway when respectively bound to NICD or histone deacetylases (HDACs). Compared with controls, NICD-mut transfectants had RBPJ preferentially complexed to NICD and showed higher levels of HDACs interacting with the promoter of the CD20 gene. Finally, treatment with the HDAC inhibitor valproic acid upregulated CD20 in both NICD-mut transfectants and primary CLL cells. In conclusion, NOTCH1 mutations are associated with low CD20 levels in CLL and are responsible for a dysregulation of HDAC-mediated epigenetic repression of CD20 expression.

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