Project description:Activating mutations in the Anaplastic Lymphoma Kinase (ALK) receptor tyrosine kinase (RTK) are found in pediatric neuroblastoma, where they are often associated with poor prognosis. To study the effects of ALK-activating mutations in a genetically controllable system we employed CRIPSR/Cas9 to incorporate orthologues of the oncogenic human driver mutations ALKF1174 and ALKY1278S in the Drosophila Alk locus. AlkF1251 and AlkY1355S mutant Drosophila exhibit phenotypes similar to that previously associated with enhanced Alk signaling. Unexpectedly, both mutant alleles are still dependent on the presence of Jeb ligand for activation, as neither can rescue mutants of the Alk ligand Jeb. However, both Alk mutant third instar brains display hyperplasia, represented by increased numbers of Alk-positive neuronal populations. Despite this hyperplasic phenotype within the central brain area, no brain tumors were observed in mutant animals. Further investigation indicated that larval brain hyperplasia in Alk mutants was not caused by significantly increased rates of proliferation, but rather by decreased levels of apoptosis in the larval brain. Using single cell RNA sequencing (scRNAseq) analysis, we identify maintained neuronal fate change during the temporal fate specification of in the mushroom body lineages, with AlkY1355S mutants displaying precocious a’b’ neuron identity. These findings shed important light on the role of Alk in perturbation of neurodevelopmental processes and highlight the potential of activating Alk mutations to promote survival in neuronal lineages
Project description:High-risk neuroblastoma (NB) currently presents significant clinical challenges. MYCN and ALK, which are often involved in high-risk NB, lead to increased replication stress in cancer cells, providing options for therapeutic exploitation. We previously identified an ATR/ALK inhibitor combination as an effective therapeutic approach in two independent genetically modified mouse NB models. Here, we identify an underlying molecular mechanism, in which ALK signalling leads to phosphorylation of ATR and CHK1, supporting an effective DNA damage response. The importance of ALK inhibition is supported by mouse data, in which monotreatment with ATRi resulted in a robust initial response, but subsequent relapse, in contrast to a 14-day ALKi/ATRi combination treatment that resulted in robust and sustained responses. Finally, we show that the remarkable response to the 14-day combined ATR/ALK inhibition protocol reflects a robust differentiation response in the tumour, reprogramming tumour cells to a neuronal/Schwann cell lineage identity. Our results identify a unique ability of ATR inhibition to trigger neuroblastoma differentiation and underscore the importance of further exploring combined ALK/ATR inhibition in NB, particularly in high-risk patient groups with oncogene-induced replication stress.
Project description:Anaplastic Lymphoma Kinase (ALK) most frequently mutated in neuroblastoma (NB) and is atractive molecular target for therapy. However, efficacy of the ALK inhibitor against ALK-amplified NB is unclear. To elucidate genetic alterations induced by treatment of the ALK inhibitor, we compared expression profile between ALK inhibitor-treated and DMSO-treated NB39nu cells using Agilent SurePrint G3 Human GE 8x60K V2 Microarray Kit
Project description:Neuroblastoma is an embryonal neoplasm that remains of dramatic prognosis in its aggressive forms. Activating mutations of the ALK tyrosine kinase receptor have been identified in sporadic and familial cases of this cancer. We generated knock-in mice carrying the two most frequent Alk mutations observed in neuroblastoma patients. We used microarrays to detail the global programme of gene expression underlying the impact of ALK mutations on neuroblastoma formation in a MYCN amplified background. We selected several murine neuroblastoma tumors for RNA extraction and hybridization on Affymetrix microarrays. We generated three groups of tumors: 10 MYCN amplified tumors, 11 MYCN amplified/ALK F1174L tumors and 10 MYCN amplified/ALK R1275Q tumors.
Project description:High anaplastic lymphoma kinase (ALK) protein levels may be correlated with an unfavorable prognosis in neuroblastoma (NBL) patients, regardless of ALK mutation status. We therefore examined the correlation between levels of ALK, phosphorylated ALK (pALK) and downstream signaling proteins and response to ALK inhibition in a large panel of both ALK mutated (MUT) and wild type (WT) NBL cell lines. Six of the nineteen NBL cell lines had a point mutation and four an amplification of the ALK gene. ALK amplified cell lines showed similar ALK levels and ALK inhibitor sensitivity as WT cell lines and were therefore co-analyzed. The ALK mRNA (p=0.043), ALK 220 kDa (p=0.009) and ALK 140 kDa (p=0.025) protein levels were higher in ALK mutant (n=6) than WT cell lines (n=13). ALK mRNA and protein levels significantly correlated with ERK1 and ERK2 protein levels, and also with PHOX2B mRNA levels, a neural differentiation marker which is mutated in NBL. Response to ALK inhibitor TAE684 was also significantly correlated with ALK levels. ALK mutant cell lines (n=4) demonstrated a higher sensitivity towards ALK inhibitor TAE684 (14.9 fold more sensitive, p=0.004) than eight WT cell lines. These results underline the importance of ALK mutations but also ALK levels for response to ALK inhibitors in NBL cell lines. Furthermore, the strong correlation of PHOX2B and ALK suggests that neural differentiation stage may be correlated with ALK levels in neuroblastoma. These data will enhance understanding of ALK inhibitor response in future patient trials. To study differentially expressed genes in the neuroblastoma cell lines described in the protein analysis study above, 15 cell lines and 2 derivative cell lines were used.
Project description:The goal of this study is to identify the mechanism for how ALK promotes tumorigenesis in neuroblastoma. We developed a human stem cell model of neuroblastoma and generated isogenic tumors using MYCN and MYCN/ALK. RNAseq analysis of both tumors revealed an enrichment in focal adhesion signaling and allowed us to find POSTN as a key mediator of ALK-mediated tumor growth.
Project description:The prognosis of advanced stage neuroblastoma patients remains poor and, despite intensive therapy, the 5-year survival rate remains less than 50%. We previously identified histone deacetylase (HDAC) 8 as an indicator of poor clinical outcome and a selective drug target for differentiation therapy in vitro and in vivo. Here we performed kinome-wide RNAi screening to identify genes that are synthetically lethal with HDAC8 inhibitors. These experiments identified the neuroblastoma predisposition gene ALK as a candidate gene. Accordingly, the combination of the ALK/MET inhibitor crizotinib and selective HDAC8 inhibitors (3-6μM PCI-34051 or 10μM 20a) efficiently killed neuroblastoma cell lines carrying wildtype ALK (SK-N-BE(2)-C, IMR5/75), amplified ALK (NB-1), and those carrying the activating ALK F1174L mutation (Kelly), and, in cells carrying the activating R1275Q mutation (LAN-5), combination treatment decreased viable cell count. The effective dose of crizotinib in neuroblastoma cell lines ranged from 0.05μM (ALK-amplified) to 0.8μM (wildtype ALK). The combinatorial inhibition of ALK and HDAC8 also decreased tumor growth in an in vivo zebrafish xenograft model. Bioinformatic analyses revealed that the mRNA expression level of HDAC8 was significantly correlated with that of ALK in two independent patient cohorts, the Academic Medical Center cohort (n=88) and the German Neuroblastoma Trial cohort (n=649), and co-expression of both target genes identified patients with very poor outcome. Mechanistically, HDAC8 and ALK converge at the level of receptor tyrosine kinase (RTK) signaling and their downstream survival pathways, such as ERK signaling. Combination treatment of HDAC8 inhibitor with crizotinib efficiently blocked the activation of growth receptor survival signaling and shifted the cell cycle arrest and differentiation phenotype toward effective cell death of neuroblastoma cell lines, including sensitization of resistant models, but not of normal cells. These findings reveal combined targeting of ALK and HDAC8 as a novel strategy for the treatment of neuroblastoma.
Project description:Neuroblastoma is an embryonal neoplasm that remains of dramatic prognosis in its aggressive forms. Activating mutations of the ALK tyrosine kinase receptor have been identified in sporadic and familial cases of this cancer. We generated knock-in mice carrying the two most frequent Alk mutations observed in neuroblastoma patients. We used microarrays to detail the global programme of gene expression underlying the impact of ALK mutations on neuroblastoma formation in a MYCN amplified background.
Project description:High anaplastic lymphoma kinase (ALK) protein levels may be correlated with an unfavorable prognosis in neuroblastoma (NBL) patients, regardless of ALK mutation status. We therefore examined the correlation between levels of ALK, phosphorylated ALK (pALK) and downstream signaling proteins and response to ALK inhibition in a large panel of both ALK mutated (MUT) and wild type (WT) NBL cell lines. Six of the nineteen NBL cell lines had a point mutation and four an amplification of the ALK gene. ALK amplified cell lines showed similar ALK levels and ALK inhibitor sensitivity as WT cell lines and were therefore co-analyzed. The ALK mRNA (p=0.043), ALK 220 kDa (p=0.009) and ALK 140 kDa (p=0.025) protein levels were higher in ALK mutant (n=6) than WT cell lines (n=13). ALK mRNA and protein levels significantly correlated with ERK1 and ERK2 protein levels, and also with PHOX2B mRNA levels, a neural differentiation marker which is mutated in NBL. Response to ALK inhibitor TAE684 was also significantly correlated with ALK levels. ALK mutant cell lines (n=4) demonstrated a higher sensitivity towards ALK inhibitor TAE684 (14.9 fold more sensitive, p=0.004) than eight WT cell lines. These results underline the importance of ALK mutations but also ALK levels for response to ALK inhibitors in NBL cell lines. Furthermore, the strong correlation of PHOX2B and ALK suggests that neural differentiation stage may be correlated with ALK levels in neuroblastoma. These data will enhance understanding of ALK inhibitor response in future patient trials.
Project description:Anaplastic lymphoma kinase (ALK) fusion variants in non-small-cell-lung cancer (NSCLC) consist of numerous dimerising fusion partners, with the most common being EML4. Clinical data suggests that the degree of treatment benefit in response to ALK tyrosine kinase inhibitors (TKIs) differs among the variant present in the patient tumor. Therefore, a better understanding the oncogenic signaling networks driven by different ALK-fusion variants is important. Here, we developed highly controlled doxycycline-inducible cell models bearing four different ALK fusion proteins, namely EML4-ALK-V1, EML4-ALK-V3, KIF5B-ALK, and TFG-ALK, in the context of non-tumorigenic NL20 human bronchial epithelial cells. These were complimented by patient-derived NSCLC cell lines harboring either EML4-ALK-V1 or EML4-ALK-V3 fusions. RNAseq and phosphoproteomics analysis were employed to identify dysregulated genes and hyper/hypo-phosphorylated proteins associated with ALK fusion expression. Among ALK fusion induced responses, we noted a robust inflammatory signature that included up-regulation of the Serpin B4 serine protease inhibitor in both NL20-inducible cell models and ALK-positive NSCLC patient-derived cell lines. We show that STAT3 is a major transcriptional regulator of SERPINB4 downstream of ALK fusions, along with NF-B and AP1. The upregulation of SERPINB4 promotes survival of ALK fusion expressing cells and inhibits natural killer (NK) cell-mediated cytotoxicity. In conclusion, our study reveals a novel ALK downstream survival axis that regulates Serpin B4 expression and identifies a molecular target that has potential for therapeutic impact targeting the immune response together with ALK TKIs in NSCLC.