Expression of the oncogenic NPM-ALK chimeric protein in human lymphoid T-cells inhibits drug-induced, but not Fas-induced apoptosis

Catherine Greenland, Christian Touriol, Grégory Chevillard, Stephan W. Morris, Renyuan Bai, Justus Duyster, Georges Delsol, Michèle Allouche

Research output: Contribution to journalArticlepeer-review

Abstract

Anaplastic large cell lymphomas (ALCLs) are frequently associated with the t(2;5)(p23;q35) translocation, leading to the expression of NPM-ALK, a fusion protein linking nucleophosmin and anaplastic lymphoma kinase, a receptor tyrosine kinase. In ALCLs, dimerization of NPM-ALK leads to constitutive autophosphorylation and activation of the kinase, necessary for NPM-ALK oncogenicity. To investigate whether NPM-ALK, like other oncogenic tyrosine kinases, can inhibit drug-induced apoptosis, we permanently transfected NPM-ALK into Jurkat T-cells. As in ALCLs, NPM-ALK was expressed as a constitutively kinase-active 80 kDa protein, and could be detected by immunocytochemistry in nucleoli, nuclei and cytoplasm. Doxorubicin-induced apoptosis (assessed by cell morphology and annexin V-FITC binding) was significantly inhibited in two independent NPM-ALK-expressing clones (5.2±1.8 and 7.5±0.8% apoptosis), compared to control vector-transduced cells (36±6.7%). Similar results were observed with etoposide. In contrast, Fas-induced apoptosis was not inhibited. Cytochrome c release into the cytosol was delayed in doxorubicin-, but not anti-Fas-treated transfectant cells, indicating that apoptosis inhibition occurred upstream of mitochondrial events. Using NPM-ALK mutants, we demonstrated that inhibition of drug-induced apoptosis: (1) requires functional kinase activity, (2) does not involve phospholipase C-γ, essential for NPM-ALK-mediated mitogenicity and (3) appears to be phosphoinositide 3-kinase independent, despite a strong Akt/PKB activation observed in wild type NPM-ALK-expressing cells. These results suggest that the NPM-ALK antiapoptotic and mitogenic pathways are distinct.

Original languageEnglish (US)
Pages (from-to)7386-7397
Number of pages12
JournalOncogene
Volume20
Issue number50
DOIs
StatePublished - Nov 1 2001
Externally publishedYes

Keywords

  • ALK
  • Anaplastic large cell lymphoma
  • Apoptosis
  • Chemotherapy
  • Tyrosine kinase

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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