Repository logo
 

Excess of NPM-ALK oncogenic signaling promotes cellular apoptosis and drug dependency.


Type

Article

Change log

Authors

Ceccon, Monica 
Merlo, Maria Elena Boggio 
Mologni, Luca 
Poggio, Teresa 
Varesio, Lydia M 

Abstract

Most of the anaplastic large-cell lymphoma (ALCL) cases carry the t(2;5; p23;q35) that produces the fusion protein NPM-ALK (nucleophosmin-anaplastic lymphoma kinase). NPM-ALK-deregulated kinase activity drives several pathways that support malignant transformation of lymphoma cells. We found that in ALK-rearranged ALCL cell lines, NPM-ALK was distributed in equal amounts between the cytoplasm and the nucleus. Only the cytoplasmic portion was catalytically active in both cell lines and primary ALCL, whereas the nuclear portion was inactive because of heterodimerization with NPM1. Thus, about 50% of the NPM-ALK is not active and sequestered as NPM-ALK/NPM1 heterodimers in the nucleus. Overexpression or relocalization of NPM-ALK to the cytoplasm by NPM genetic knockout or knockdown caused ERK1/2 (extracellular signal-regulated protein kinases 1 and 2) increased phosphorylation and cell death through the engagement of an ATM/Chk2- and γH2AX (phosphorylated H2A histone family member X)-mediated DNA-damage response. Remarkably, human NPM-ALK-amplified cell lines resistant to ALK tyrosine kinase inhibitors (TKIs) underwent apoptosis upon drug withdrawal as a consequence of ERK1/2 hyperactivation. Altogether, these findings indicate that an excess of NPM-ALK activation and signaling induces apoptosis via oncogenic stress responses. A 'drug holiday' where the ALK TKI treatment is suspended could represent a therapeutic option in cells that become resistant by NPM-ALK amplification.

Description

Keywords

Animals, Apoptosis, Blotting, Western, Cell Line, Tumor, Cell Survival, Cells, Cultured, Crizotinib, Dose-Response Relationship, Drug, Drug Synergism, Extracellular Signal-Regulated MAP Kinases, Histones, Humans, Hydrazines, Lymphoma, Large-Cell, Anaplastic, Mice, Inbred NOD, Mice, Knockout, Mice, SCID, Microscopy, Confocal, Nucleophosmin, Oncogene Proteins, Fusion, Protein Kinase Inhibitors, Protein-Tyrosine Kinases, Pyrazoles, Pyridines, RNA Interference, Signal Transduction, Transplantation, Heterologous, Triazoles

Journal Title

Oncogene

Conference Name

Journal ISSN

0950-9232
1476-5594

Volume Title

Publisher

Springer Science and Business Media LLC
Sponsorship
Leukaemia & Lymphoma Research (12065)
We thank Maria Stella Scalzo for technical support, Dr Emanuela Colombo for kindly providing MEFs that lack NPM1 (MEF NPM−/−p53−/−) and control fibroblasts (MEF p53−/−), Dr Guido Serini for the use of his confocal microscopy unit at the Candiolo Cancer Institute—IRCCS, Torino, Italy. We also thank Ariad Pharmaceutical, Pfizer, Astellas and Novartis that kindly provided all drugs used in this study. This work was supported by the Regione Lombardia (ID14546A) and Fondazione Berlucchi Onlus Grant 2014 (to CGP), and by grants FP7 ERC-2009-StG (Proposal No. 242965—‘Lunely’); Associazione Italiana per la Ricerca sul Cancro (AIRC) Grant IG-12023; Koch Institute/DFCC Bridge Project Fund; Ellison Foundation Boston; Worldwide Cancer Research Association (former AICR) grant 12-0216; the Grant for Oncology Innovation by Merck-Serono and R01 CA196703-01 (to RC).