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The lymphoma-associated NPM-ALK oncogene elicits a p16INK4a/pRb-dependent tumor-suppressive pathway

Paola Martinelli1, Paola Bonetti, Cristina Sironi

  • 1Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, Milan, Italy.

Blood
|April 27, 2011
PubMed

Insights

Oncogene-induced senescence (OIS) acts as a tumor barrier. The p16INK4a/pRb pathway, not ARF/p53, drives OIS in anaplastic large cell lymphomas, offering a new therapeutic target.

Area of Science:

  • Oncology
  • Cellular Biology
  • Molecular Biology

Background:

  • Oncogene-induced senescence (OIS) is a crucial tumor suppressor mechanism.
  • The ARF/p53 pathway is commonly involved in OIS and frequently mutated in cancer.
  • Some oncogenes bypass ARF/p53, implying alternative senescence pathways.

Purpose of the Study:

  • To investigate the OIS pathway activated by NPM-ALK, the oncogene in anaplastic large cell lymphomas (ALCLs).
  • To determine the role of the p16INK4a/pRb pathway in NPM-ALK-driven lymphomagenesis.
  • To explore therapeutic strategies targeting senescence in ALCLs.

Main Methods:

  • Induction of OIS by NPM-ALK in primary fibroblasts and hematopoietic progenitors.
  • Analysis of cell cycle arrest, DNA damage, and pathway activation (ARF/p53, p16INK4a/pRb).
  • Utilized transgenic mouse models of NPM-ALK lymphomagenesis and analyzed human ALCL samples.
  • Investigated the epigenetic regulation of p16INK4a expression via Jmjd3.

Main Results:

  • NPM-ALK induces cell cycle arrest and DNA damage, inhibiting p53 but activating the p16INK4a/pRb pathway.
  • p16INK4a is essential for senescence in premalignant lesions and tumor suppression in NPM-ALK-driven lymphoma.
  • Human ALCLs lack p16INK4a and pRb expression, with NPM-ALK upregulating Jmjd3 to suppress p16INK4a transcriptionally.
  • Histone demethylase Jmjd3 mediates NPM-ALK-induced silencing of p16INK4a.

Conclusions:

  • The p16INK4a/pRb pathway serves as an alternative senescence mechanism to ARF/p53 in response to oncogene activation.
  • NPM-ALK oncogene inhibits p53 and activates p16INK4a/pRb pathway, leading to senescence.
  • Restoring p16INK4a expression presents a potential therapeutic strategy for ALCLs and other tumors bypassing ARF/p53.

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