While the constitutive activation of chimeric NPM-ALK molecules could be shown, no evidence was found for induced or constitutively activated ALK receptors in neuroblastoma, melanoma or breast carcinoma cell lines.
ALK-ShcC signal activation, possibly caused by co-amplification with the N-myc gene, might give additional effects on malignant tumor progression of neuroblastoma.
In contrast to agonist monoclonal antibodies, both Pleiotrophin.15 and Pleiotrophin.18 failed to activate ALK in neuroblastoma and glioblastoma cells expressing this receptor.
Here we show that the anaplastic lymphoma kinase (ALK), originally identified as a fusion kinase in a subtype of non-Hodgkin's lymphoma (NPM-ALK) and more recently in adenocarcinoma of lung (EML4-ALK), is also a frequent target of genetic alteration in advanced neuroblastoma.
Thus, activating alleles of the ALK receptor tyrosine kinase are present in primary neuroblastoma tumours and in established neuroblastoma cell lines, and confer sensitivity to ALK inhibition with small molecules, providing a molecular rationale for targeted therapy of this disease.
A variety of human malignancies have anaplastic lymphoma kinase (ALK) translocations, amplifications, or oncogenic mutations, including anaplastic large cell lymphoma, inflammatory myofibroblastic tumors, non-small cell lung cancer, and neuroblastoma.
Following this possibility, we first confirmed a striking correlation between the transcription levels of ALK, PHOX2B and its direct target PHOX2A in a panel of NB cell lines.
We undertook mutational analysis of the genes known to predispose to non-syndromic familial Wilms tumor (WT1) or neuroblastoma (PHOX2B, ALK) which excluded these as the underlying predisposition genes in the nine families.
We carried out a meta-analysis of 709 neuroblastoma tumors to determine their frequency and mutation spectrum in relation to genomic and clinical parameters, and studied the prognostic significance of ALK copy number and expression.
Activating mutations within the full-length ALK kinase domain, most commonly R1275Q and F1174L, which play a major role in neuroblastoma, were recently identified.
Recently, somatic amplification and gain-of-function mutations of the anaplastic lymphoma receptor tyrosine kinase (ALK) gene, either somatic or germline, were identified in a significant proportion of NB cases.
However, during disease progression, mutation of amino acid F1174 to a serine within the ALK kinase domain was observed, which correlated with aggressive neuroblastoma progression in the patient.
Relative to free ALK-siRNA, anti-GD₂-targeted liposomal formulations of ALK-siRNA had low plasma clearance, increased siRNA stability, and improved binding, uptake, silencing and induction of cell death, and specificity for NB cells.In NB xenografts, intravenous (i.v.) injection of the targeted ALK-siRNA liposomes showed gene-specific antitumor activity with no side effects.
We measured protein levels by western blot and ALK inhibitor sensitivity (TAE684) by viability assays in 19 NBL cell lines of which 6 had a point mutation and 4 an amplification of the ALK gene.