title: Characterization of rearrangements involving the ALK gene reveals a novel truncated form associated with tumor aggressiveness in neuroblastoma.
abstract: Activating mutations of the ALK gene have been identified in sporadic and familial cases of neuroblastoma (NB), a cancer of the peripheral nervous system, and are thought to be the primary mechanism of oncogenic activation of this receptor in this pediatric neoplasm. To address the possibility that ALK activation may occur through genomic rearrangements as detected in other cancers, we first took advantage of high-resolution array-comparative genomic hybridization to search for ALK rearrangements in NB samples. Using complementary experiments by capture/paired-end sequencing and FISH experiments, various types of rearrangements were fully characterized, including partial gains or amplifications, in several NB cell lines and primary tumors. In the CLB-Bar cell line, we described a genomic rearrangement associated with an amplification of the ALK locus, leading to the expression of a 170 kDa protein lacking part of the extracellular domain encoded by exons 4 to 11, named ALK(Δ4-11). Analysis of genomic DNA from the tumor at diagnosis and relapse revealed that the ALK gene was amplified at diagnosis but that the rearranged ALK allele was observed at the relapse stage only, suggesting that it may be implicated in tumor aggressiveness. Consistently, oncogenic and tumorigenic properties of the ALK(Δ4-11) variant were shown after stable expression in NIH3T3 cells. Moreover, we documented an increased constitutive kinase activity of this variant, as well as an impaired maturation and retention into intracellular compartments. These results indicate that genomic rearrangements constitute an alternative mechanism to ALK point mutations resulting in receptor activation.
authors.affiliation: Inserm U830, Institut Curie, Centre de Recherche, Paris, France.
authors.forename: Alex
authors.initials: A
authors.lastname: Cazes
authors.forename: Caroline
authors.initials: C
authors.lastname: Louis-Brennetot
authors.forename: Pierre
authors.initials: P
authors.lastname: Mazot
authors.forename: Florent
authors.initials: F
authors.lastname: Dingli
authors.forename: Bérangère
authors.initials: B
authors.lastname: Lombard
authors.forename: Valentina
authors.initials: V
authors.lastname: Boeva
authors.forename: Romain
authors.initials: R
authors.lastname: Daveau
authors.forename: Julie
authors.initials: J
authors.lastname: Cappo
authors.forename: Valérie
authors.initials: V
authors.lastname: Combaret
authors.forename: Gudrun
authors.initials: G
authors.lastname: Schleiermacher
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Jouannet
authors.forename: Sandrine
authors.initials: S
authors.lastname: Ferrand
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Pierron
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Barillot
authors.forename: Damarys
authors.initials: D
authors.lastname: Loew
authors.forename: Marc
authors.initials: M
authors.lastname: Vigny
authors.forename: Olivier
authors.initials: O
authors.lastname: Delattre
authors.forename: Isabelle
authors.initials: I
authors.lastname: Janoueix-Lerosey
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D045744:Cell Line, Tumor; D055028:Comparative Genomic Hybridization; D015321:Gene Rearrangement / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D017404:In Situ Hybridization, Fluorescence; D009447:Neuroblastoma / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*
chemical_list: C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases