Anaplastic lymphoma kinase: signalling in development and disease

Phosphoproteomic Profiling Reveals ALK and MET as Novel Actionable Targets across Synovial Sarcoma Subtypes

Despite intensive multimodal treatment of sarcomas, a heterogeneous group of malignant tumors arising from connective tissue, survival remains poor. Candidate-based targeted treatments have demonstrated limited clinical success, urging an unbiased and comprehensive analysis of oncogenic signaling networks to reveal therapeutic targets and personalized treatment strategies. Here we applied mass spectrometry-based phosphoproteomic profiling to the largest and most heterogeneous set of sarcoma cell lines characterized to date and identified novel tyrosine phosphorylation patterns, enhanced tyrosine kinases in specific subtypes, and potential driver kinases. ALK was identified as a novel driver in the Aska-SS synovial sarcoma (SS) cell line via expression of an ALK variant with a large extracellular domain deletion (ALKΔ2-17). Functional ALK dependency was confirmed in vitro and in vivo with selective inhibitors. Importantly, ALK immunopositivity was detected in 6 of 43 (14%) of SS patient specimens, one of which exhibited an ALK rearrangement. High PDGFRα phosphorylation also characterized SS cell lines, which was accompanied by enhanced MET activation in Yamato-SS cells. Although Yamato-SS cells were sensitive to crizotinib (ALK/MET-inhibitor) but not pazopanib (VEGFR/PDGFR-inhibitor) monotherapy in vitro, synergistic effects were observed upon drug combination. In vivo, both drugs were individually effective, with pazopanib efficacy likely attributable to reduced angiogenesis. MET or PDGFRα expression was detected in 58% and 84% of SS patients, respectively, with coexpression in 56%. Consequently, our integrated approach has led to the identification of ALK and MET as promising therapeutic targets in SS. Cancer Res; 77(16); 4279-92. ©2017 AACR.

Alpha-tocopherol attenuates the anti-tumor activity of crizotinib against cells transformed by NPM-ALK

Anaplastic large cell lymphomas (ALCL) are mainly characterized by harboring the fusion protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). The ALK inhibitor, crizotinib specifically induced apoptosis in Ba/F3 cells expressing NPM-ALK by inhibiting the activation of NPM-ALK and its downstream molecule, signal transducer and activator of transcription factor 3 (STAT3). We found that α-tocopherol, a major component of vitamin E, attenuated the effects of crizotinib independently of its anti-oxidant properties. Although α-tocopherol suppressed the inhibitory effects of crizotinib on the signaling axis including NPM-ALK and STAT3, it had no influence on the intake of crizotinib into cells. Crizotinib also directly inhibited the kinase activity of NPM-ALK; however, this inhibitory effect was not altered by the co-treatment with α-tocopherol. Whereas the nuclear localization of NPM-ALK was disappeared by the treatment with crizotinib, the co-treatment with α-tocopherol swept the effect of crizotinib and caused the localization of NPM-ALK in nucleus. The administration of α-tocopherol attenuated the anti-tumor activity of crizotinib against NPM-ALK-provoked tumorigenesis in vivo. Furthermore, the α-tocopherol-induced inhibition of crizotinib-caused apoptosis was also observed in NPM-ALK-positive cells derived from ALCL patients, namely, SUDHL-1 and Ki-JK. Collectively, these results not only revealed the novel mechanism underlying crizotinib-induced apoptosis in NPM-ALK-positive cells, but also suggest that the anti-tumor effects of crizotinib are attenuated when it is taken in combination with vitamin E.

Spotlight on ceritinib in the treatment of ALK+ NSCLC: design, development and place in therapy

The identification of echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) fusion gene in non-small cell lung cancer (NSCLC) has radically changed the treatment of a subset of patients harboring this oncogenic driver. Crizotinib was the first ALK tyrosine kinase inhibitor to receive fast approval and is currently indicated as the first-line therapy for advanced, ALK-positive NSCLC patients. However, despite crizotinib's efficacy, patients almost invariably progress, with the central nervous system being one of the most common sites of relapse. Different mechanisms of acquired resistance have been identified, including secondary ALK mutations, ALK copy number alterations and activation of bypass tracks. Different highly potent and brain-penetrant next-generation ALK inhibitors have been developed and tested in NSCLC patients with ALK rearrangements. Ceritinib, a structurally distinct and selective ALK inhibitor, showed 20 times higher potency than crizotinib in inhibiting ALK and had activity against the most common crizotinib-resistant mutations, including L1196M and G1269A, in preclinical models. In Phase I and II studies, ceritinib demonstrated pronounced activity in both crizotinib-naïve and crizotinib-refractory patients, with responses observed regardless of the presence of ALK resistance mutations. Ceritinib was the first ALK inhibitor to be approved for the treatment of crizotinib-refractory, ALK-rearranged NSCLC, and recent results from a Phase III study have demonstrated superior efficacy compared to standard chemotherapy in the first- and second-line setting. We provide an extensive overview of ceritinib from the design of the compound through preclinical data until efficacy and toxicity results from Phase I-III clinical studies. We review the molecular alterations associated with resistance to ceritinib and highlight the importance of obtaining tumor biopsy at progression to tailor therapy based upon the underlying resistance mechanism. We finally provide an outlook on novel rational therapeutic combinations.

Tumor Antigen and Receptor Densities Regulate Efficacy of a Chimeric Antigen Receptor Targeting Anaplastic Lymphoma Kinase

We explored the utility of targeting anaplastic lymphoma kinase (ALK), a cell surface receptor overexpressed on pediatric solid tumors, using chimeric antigen receptor (CAR)-based immunotherapy. T cells expressing a CAR incorporating the single-chain variable fragment sequence of the ALK48 mAb linked to a 4-1BB-CD3ζ signaling domain lysed ALK-expressing tumor lines and produced interferon-gamma upon antigen stimulation but had limited anti-tumor efficacy in two xenograft models of human neuroblastoma. Further exploration demonstrated that cytokine production was highly dependent upon ALK target density and that target density of ALK on neuroblastoma cell lines was insufficient for maximal activation of CAR T cells. In addition, ALK CAR T cells demonstrated rapid and complete antigen-induced loss of receptor from the T cell surface via internalization. Using a model that simultaneously modulated antigen density and CAR expression, we demonstrated that CAR functionality is regulated by target antigen and CAR density and that low expression of either contributes to limited anti-tumor efficacy of the ALK CAR. These data suggest that stoichiometric relationships between CAR receptors and target antigens may significantly impact the anti-tumor efficacy of CAR T cells and that manipulation of these parameters could allow precise tuning of CAR T cell activity.

Partial deletion of the ALK gene in ALK-positive anaplastic large cell lymphoma

Anaplastic lymphoma kinase (ALK) protein is an orphan receptor tyrosine kinase that is constitutively activated by aberrant translocations of the ALK gene in anaplastic large cell lymphoma, ALK-positive and several other cancers. Additionally, aberrant mutation and amplification of the ALK gene, resulting in ALK kinase activation, were detected mainly in neuroblastoma. Recently, truncated ALK protein was also reported in neuroblastoma. Here, we describe a novel truncated form of the ALK transcript with in-frame skipping through exons 2 to 17 (ALKΔ2-17) in anaplastic large cell lymphoma, ALK-positive. The ALKΔ2-17 showed ligand-independent deregulated phosphorylation that initiated strong STAT3 signalling in NIH3T3 cells. The ALKΔ2-17-transduced NIH3T3 cells showed oncogenic potential in a colony formation assay. Our data indicate that the aberrant deletion of the ALK gene might be oncogenic, providing a novel insight into the oncogenic role of the ALK pathway.

Therapeutic silence of pleiotrophin by targeted delivery of siRNA and its effect on the inhibition of tumor growth and metastasis

Pleiotrophin (PTN) is a secreted cytokine that is expressed in various cancer cell lines and human tumor such as colon cancer, lung cancer, gastric cancer and melanoma. It plays significant roles in angiogenesis, metastasis, differentiation and cell growth. The expression of PTN in the adult is limited to the hippocampus in an activity-dependent manner, making it a very attractive target for cancer therapy. RNA interference (RNAi) offers great potential as a new powerful therapeutic strategy based on its highly specific and efficient silencing of a target gene. However, efficient delivery of small interfering RNA (siRNA) in vivo remains a significant hurdle for its successful therapeutic application. In this study, we first identified, on a cell-based experiment, applying a 1:1 mixture of two PTN specific siRNA engenders a higher silencing efficiency on both mRNA and protein level than using any of them discretely at the same dose. As a consequence, slower melanoma cells growth was also observed for using two specific siRNA combinatorially. To establish a robust way for siRNA delivery in vivo and further investigate how silence of PTN affects tumor growth, we tested three different methods to deliver siRNA in vivo: first non-targeted in-vivo delivery of siRNA via jetPEI; second lung targeted delivery of siRNA via microbubble coated jetPEI; third tumor cell targeted delivery of siRNA via transferrin-polyethylenimine (Tf-PEI). As a result, we found that all three in-vivo siRNAs delivery methods led to an evident inhibition of melanoma growth in non-immune deficiency C57BL/6 mice without a measureable change of ALT and AST activities. Both targeted delivery methods showed more significant curative effect than jetPEI. The lung targeted delivery by microbubble coated jetPEI revealed a comparable therapeutic effect with Tf-PEI, indicating its potential application for target delivery of siRNA in vivo.

ALK Protein Expression Is Related to Neuroblastoma Aggressiveness But Is Not Independent Prognostic Factor

PURPOSE

In this study, anaplastic lymphoma kinase (ALK) mutation and amplification, ALK protein expression, loss of the nuclear alpha thalassemia/mental retardation syndrome X-linked (ATRX) protein, and telomerase reverse transcriptase (TERT) protein expressionwere studied to investigate potential correlations between these molecular characteristics and clinical features or outcomes in neuroblastoma.

MATERIALS AND METHODS

Seventy-two patients were enrolled in this study. Polymerase chain reaction amplification and direct sequencing were used for mutation analysis. ALK and MYCN amplifications were detected by fluorescence in situ hybridization. Protein expressionwas evaluated by immunohistochemical (IHC) staining.

RESULTS

ALK mutation was found in only two patients (4.1%); ALK amplification was not detected. ALK positivity, loss of nuclear ATRX protein, TERT positivity by IHC were detected in 40 (55.6%), nine (13.0%), and 42 (59.2%) patients, respectively. The incidence of ALK expression increased in accordance with increasing tumor stage (p=0.001) and risk group (p < 0.001). The relapse rate was significantly higher in ALK⁺ patients compared to that of other patients (47.5% vs. 11.3%, p=0.007). However, there was no significant difference in relapse rate when the survival analysis was confined to the high-risk patients.

CONCLUSION

Although ALK mutation was rare and no amplification was observed, ALK protein expression was found in a significant number of patients and was correlated with advanced stage and high-risk neuroblastoma. ALK protein expression could be considered as a marker related to the aggressive neuroblastoma, but it was not the independent prognostic factor for the outcome.

ALK protein expression in pulmonary adenocarcinoma of Tunisian patients

BACKGROUND

It is now necessary to determine ALK status in order to use targeted therapy.

AIM

herein, we assess immunohistochemical profile of ALK protein in a series of Tunisian patients with pulmonary adenocarcinoma.

MATERIALS AND METHODS

ALK protein expression was studied applying the D5F3 antibody with a fully automated Ventana CDx technique on a series of 19 patients.

RESULTS

Positive ALK expression was found in one case (5.2%) corresponding to a papillary adenocarcinoma which showed a strong granular and homogenous cytoplasmic staining. The patient was a 30-years-old woman.

CONCLUSION

The frequency of positive ALK expression based on immunohistochemistry in our series was similar to that reported in the world literature.

Neuroblastoma treatment in the post-genomic era

Neuroblastoma is an embryonic malignancy of early childhood originating from neural crest cells and showing heterogeneous biological, morphological, genetic and clinical characteristics. The correct stratification of neuroblastoma patients within risk groups (low, intermediate, high and ultra-high) is critical for the adequate treatment of the patients.

High-throughput technologies in the Omics disciplines are leading to significant insights into the molecular pathogenesis of neuroblastoma. Nonetheless, further study of Omics data is necessary to better characterise neuroblastoma tumour biology. In the present review, we report an update of compounds that are used in preclinical tests and/or in Phase I-II trials for neuroblastoma. Furthermore, we recapitulate a number of compounds targeting proteins associated to neuroblastoma: MYCN (direct and indirect inhibitors) and downstream targets, Trk, ALK and its downstream signalling pathways. In particular, for the latter, given the frequency of ALK gene deregulation in neuroblastoma patients, we discuss on second-generation ALK inhibitors in preclinical or clinical phases developed for the treatment of neuroblastoma patients resistant to crizotinib.

We summarise how Omics drive clinical trials for neuroblastoma treatment and how much the research of biological targets is useful for personalised medicine. Finally, we give an overview of the most recent druggable targets selected by Omics investigation and discuss how the Omics results can provide us additional advantages for overcoming tumour drug resistance.

ALK gene alterations in cancer: biological aspects and therapeutic implications

ALK was first reported in 1994 as a translocation in anaplastic large cell lymphoma and then described with different abnormalities in a number of tumors. Recently, a shortly accumulated biomedical research clarified the numerous biological processes underlying its ability to support cancer development, growth and progression. Advent of precision medicine has finally provided unexpected advances, leading to the development of ALK-targeting inhibitors with superior efficacy as compared with standard chemotherapy regimens, as well as the identification of resistance mechanisms and the creation of ‘next-generation’ treatments. This review summarizes the current understanding of ALK-driven cancers from the oncogenesis and mutation frequency by The Cancer Genome Atlas database through the diagnostic approach, to an updated portrait of available tyrosine kinase inhibitors, considering their effectiveness in cancer treatment, the molecular reasons of therapeutic failure, and the actual and future ways to overcome resistances.

Targeted Therapies for Non-Small Cell Lung Cancer: An Update on Epidermal Growth Factor Receptor and Anaplastic Lymphoma Kinase Inhibitors

BACKGROUND

The development of targeted therapies has revolutionized the treatment of advanced non-small cell lung cancer (NSCLC), with new clinical trials and therapies consistently providing new information. This rapidly changing field mandates ongoing education for nursing professionals whose foremost priority is patient care.

OBJECTIVES

This review aims to summarize the history and current status of targeted therapies for NSCLC, focusing on two types of drugs that have had the most impact to date.

METHODS

The safety profiles of first- and second-generation EGFR and ALK inhibitors are described, and strategies for the management of the most commonly experienced adverse events are summarized. Information is also provided to help identify which patients might be eligible for treatment with EGFR or ALK inhibitors in addition to the implications of targeted therapies.

FINDINGS

Therapies designed to target specific molecular features of individual tumor cells are one of the most important developments in treating NSCLC. The safety profiles of targeted therapies differ greatly from chemotherapy and present unique challenges to nurses. Education of nurses and patients on implementation of effective adverse event management and improvement in patient adherence will maximize the benefits of these drugs.

Clinicopathological Features and Therapeutic Responses of Chinese Patients with Advanced Lung Adenocarcinoma Harboring an Anaplastic Lymphoma Kinase Rearrangement

BACKGROUND

Presence of anaplastic lymphoma kinase (ALK) rearrangement is an indication for crizotinib in the treatment of patients with advanced or metastatic lung adenocarcinoma. Here, we sought to elucidate the association between clinicopathological features and ALK rearrangement status in Chinese patients with advanced lung adenocarcinoma harboring an ALK rearrangement.

PATIENTS AND METHODS

ALK rearrangement status was determined using immunohistochemistry (IHC) in tumor tissues from 120 patients with advanced lung adenocarcinoma, and further assessed by fluorescence in situ hybridization (FISH) assay. The associations between ALK rearrangement status and clinicopathological features were analyzed.

RESULTS

According to IHC testing, the ALK-positive rate among the advanced lung adenocarcinoma patients was 6.67% (8/120). FISH validation found 5 patients with ALK rearrangement among the 8 IHC-positive cases. No significant difference was observed regarding age, sex, or smoking status between FISH-positive and -negative patients (p > 0.05). None of the 5 FISH-positive patients benefited from first-line chemotherapy.

CONCLUSION

IHC can be used as a reliable method for ALK rearrangement screening in patients with lung adenocarcinoma, but further FISH validation is imperative. Presence of ALK rearrangement predicts a more aggressive biological behavior of the tumor and might be indicative of poor response to chemotherapy.

ALK: a tyrosine kinase target for cancer therapy

The anaplastic lymphoma kinase (ALK) gene plays an important physiologic role in the development of the brain and can be oncogenically altered in several malignancies, including non-small-cell lung cancer (NSCLC) and anaplastic large cell lymphomas (ALCL). Most prevalent ALK alterations are chromosomal rearrangements resulting in fusion genes, as seen in ALCL and NSCLC. In other tumors, ALK copy-number gains and activating ALK mutations have been described. Dramatic and often prolonged responses are seen in patients with ALK alterations when treated with ALK inhibitors. Three of these—crizotinib, ceritinib, and alectinib—are now FDA approved for the treatment of metastatic NSCLC positive for ALK fusions. However, the emergence of resistance is universal. Newer ALK inhibitors and other targeting strategies are being developed to counteract the newly emergent mechanism(s) of ALK inhibitor resistance. This review outlines the recent developments in our understanding and treatment of tumors with ALK alterations.

Targeted next-generation sequencing for TP53, RAS, BRAF, ALK and NF1 mutations in anaplastic thyroid cancer

Anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer with a median survival of 4-6 months. Identification of mutations contributing to aberrant activation of signaling cascades in ATC may provide novel opportunities for targeted therapy. Thirty-nine ATC samples were studied by next-generation sequencing (NGS) with an established gene panel. High quality readout was obtained in 30/39 ATC. Twenty-eight ATC harbored a mutation in at least one of the studied genes: TP53 (18/30), NF1 (11/30), ALK (6/30), NRAS (4/30), ATRX (3/30), BRAF (2/30), HRAS (2/30), KRAS (1/30). In 17/30 ATC (54 %) mutations were found in two or more genes. Twenty-one of the identified variants are listed in COSMIC as somatic mutations reported in other cancer entities. In three ATC samples no mutations were detected and none of the ATCs was positive for BRAF^V600E. The most frequent mutations were found in TP53 (60 %), followed by NF1 (37 %). ALK mutations were detected in 20 % of ATC and were more frequent than RAS or BRAF mutations. ATRX mutations were identified in 10 % of the ATC samples. These sequencing data from 30 ATC samples demonstrate the accumulation of genetic alterations in ATC because in 90 % of samples mutations were already found in the investigated nine genes alone. Mutations were found with high prevalence in established tumor suppressor and oncogenes in ATC, such as TP53 and H/K/NRAS, but also, although less frequent, in genes that may harbor the potential for targeted treatment in a subset of ATC patients, such as ALK and NF1.

Anaplastic lymphoma kinase: Role in cancer and therapy perspective

Anaplastic lymphoma kinase (ALK) is correlated with oncogenesis in different types of cancers, such as anaplastic large cell lymphoma, lung cancer, neuroblastoma, and even breast cancer, by abnormal fusion of ALK or non-fusion ALK activation. ALK is a receptor tyrosine kinase, with a single transmembrane domain, that plays an important role in development. Upon ligand binding to the extracellular domain, the receptor undergoes dimerization and subsequent autophosphorylation of the intracellular kinase domain. In recent years, ALK inhibitors have been developed for cancer treatment. These inhibitors target ALK activity and show effectiveness in ALK-positive non-small cell lung cancer. However, acquired treatment resistance makes the future of this therapy unclear; new strategies are underway to overcome the limitations of current ALK inhibitors.

Recent biologic and genetic advances in neuroblastoma: Implications for diagnostic, risk stratification, and treatment strategies

Neuroblastoma is an embryonic cancer of neural crest cell lineage, accounting for up to 10% of all pediatric cancer. The clinical course is heterogeneous ranging from spontaneous regression in neonates to life-threatening metastatic disease in older children. Much of this clinical variance is thought to result from distinct pathologic characteristics that predict patient outcomes. Consequently, many research efforts have been focused on identifying the underlying biologic and genetic features of neuroblastoma tumors in order to more clearly define prognostic subgroups for treatment stratification. Recent technological advances have placed emphasis on the integration of genetic alterations and predictive biologic variables into targeted treatment approaches to improve patient survival outcomes. This review will focus on these recent advances and the implications they have on the diagnostic, staging, and treatment approaches in modern neuroblastoma clinical management.

Analysis of the frequency of EGFR, KRAS and ALK mutations in patients with lung adenocarcinoma in Croatia

Background

Many studies have been published on the mutational status of patients with lung adenocarcinomas, and great population-based variability in mutation frequencies has been reported. The main objective of the present study was to analyze the EGFR, KRAS and ALK mutation status in a representative cohort of patients in Croatia with lung adenocarcinomas and to correlate the mutational status with clinical data.

Methods

All patients who were newly diagnosed within 6 months with histologically proven primary lung adenocarcinomas were included. Mutational analyses for EGFR and KRAS mutations were performed in a cobas z 480 analyzer. ALK immunohistochemistry was performed using the D5F3 clone on Benchmark XT instrument. Clinical data were obtained from the medical records.

Results

Of the 324 patients, 59.9 % were male. At the time of diagnosis, the patients ranged in age range from 35 to 88 years (median 63 years). Most of the patients were current smokers or former smokers (77.2 %). EGFR mutations were found in 15.7 % of the patients, and of these mutations, exon 19 deletion was the most common (45.1 %). KRAS mutations were present in 34.9 % of the patients, while 4.1 % of patients were ALK-positive. The statistical significance of the presence of mutations was detected for both gender and smoking.

Conclusion

The detected mutation rates demonstrated a slightly higher prevalence of KRAS mutations, but not a higher prevalence of EGFR mutations or ALK gene rearrangement, in comparison with the rates found in other European countries. EGFR and ALK mutational status showed a statistically significant correlation with gender as well as with smoking, while KRAS mutation status showed a statistically significant correlation only with smoking.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-016-0544-9) contains supplementary material, which is available to authorized users.

Atractylodin Inhibits Interleukin-6 by Blocking NPM-ALK Activation and MAPKs in HMC-1

Atractylodin is one of the major constituents of the rhizome of Atractylodes lancea, which is widely used in Korean traditional medicine as a remedy for the treatment of gastritis and gastric ulcers. Despite of a major constituent of widely used botanical to treat inflammatory responses little is known about anti-inflammatory effect of atractylodin in the human mast cell (HMC-1). Hence, we evaluated the effect of atractylodin on the release of IL-6, the involvement of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) and mitogen-activated protein kinases (MAPKs) in phorbol-12-myristate-13-acetate and A23187-induced HMC-1. In addition, Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), phospholipase C (PLC) gamma 1, and AKT phosphorylation relevant to NPM-ALK signal pathway were assessed. IL-6 levels in the HMC-1 stimulated by phorbol-12-myristate-13-acetate and A23187 were apparently decreased by the treatment of atractylodin. Concurrently, atractylodin not only inhibited the phosphorylation of NPM-ALK, but also suppressed the phosphorylation of JAK2, STAT3, PLC gamma 1, and AKT. Furthermore, the activated mitogen-activated protein kinases (MAPKs) by phorbol-12-myristate-13-acetate and A23187 were inhibited by atractylodin. These results suggested that atractylodin might have a potential regulatory effect on inflammatory mediator expression through blockade of both the phosphorylation of MAPKs and the NPM-ALK signaling pathway.

Crizotinib: from discovery to accelerated development to front-line treatment

Non-small-cell lung cancer (NSCLC) is associated with a poor prognosis and low survival rates, providing a strong rationale for the development of new treatment options. The discovery of ALK gene rearrangements in a subset of NSCLC specimens and the identification and development of the first-in-class ALK inhibitor crizotinib provided a personalised treatment option for patients with advanced ALK-positive NSCLC. Crizotinib demonstrated rapid and durable responses in advanced ALK-positive NSCLC patients in phase I and II studies, leading to accelerated FDA approval. Subsequent evaluation in phase III studies showed that crizotinib improved progression-free survival compared with platinum-based doublet chemotherapy in previously untreated patients and compared with pemetrexed or docetaxel in previously treated patients. Crizotinib was shown to have an acceptable safety profile and also to improve quality of life and symptom scores. Overall, crizotinib has been shown to provide a valuable first- and second-line treatment option and is now the first-line standard of care for patients with advanced ALK-positive NSCLC.

Inconsistent results in the analysis of ALK rearrangements in non-small cell lung cancer

BACKGROUND

Identification of targetable EML4-ALK fusion proteins has revolutionized the treatment of a minor subgroup of non-small cell lung cancer (NSCLC) patients. Although fluorescence in situ hybridization (FISH) is regarded as the gold standard for detection of ALK rearrangements, ALK immunohistochemistry (IHC) is often used as screening tool in clinical practice. In order to unbiasedly analyze the diagnostic impact of such a screening strategy, we compared ALK IHC with ALK FISH in three large representative Swedish NSCLC cohorts incorporating clinical parameters and gene expression data.

METHODS

ALK rearrangements were detected using FISH on tissue microarrays (TMAs), including tissue from 851 NSCLC patients. In parallel, ALK protein expression was detected using IHC, applying the antibody clone D5F3 with two different protocols (the FDA approved Ventana CDx assay and our in house Dako IHC protocol). Gene expression microarray data (Affymetrix) was available for 194 patients.

RESULTS

ALK rearrangements were detected in 1.7 % in the complete cohort and 2.0 % in the non-squamous cell carcinoma subgroup. ALK protein expression was observed in 1.8 and 1.4 % when applying the Ventana assay or the in house Dako protocol, respectively. The specificity and accuracy of IHC was high (> 98 %), while the sensitivity was between 69 % (Ventana) and 62 % (in house Dako protocol). Furthermore, only 67 % of the ALK IHC positive cases were positive with both IHC assays. Gene expression analysis revealed that 6/194 (3 %) tumors showed high ALK gene expression (≥ 6 AU) and of them only three were positive by either FISH or IHC.

CONCLUSION

The overall frequency of ALK rearrangements based on FISH was lower than previously reported. The sensitivity of both IHC assays was low, and the concordance between the FISH and the IHC assays poor, questioning current strategies to screen with IHC prior to FISH or completely replace FISH by IHC.

Efficacy of crizotinib in first-line treatment of adults with ALK-positive advanced NSCLC

INTRODUCTION

The treatment of advanced non-small cell lung cancer (NSCLC) has evolved from palliative cytotoxic chemotherapy to precise medicine based on genetic alternations over the last decade. Anaplastic lymphoma kinase (ALK) rearrangement characterizes a molecular subset of NSCLC with an impressive response to crizotinib.

AREAS COVERED

To analyze the efficacy of crizotinib in first-line treatment of adults with advanced ALK-positive NSCLC, updated data on development and recent advances of first-line crizotinib in this subset population are reviewed.

EXPERT OPINION

To date, crizotinib should be established as a standard of care in previously untreated advanced NSCLC with ALK-rearrangement. However, the efficacy of first-line crizotinib is limited by acquired resistance. Second generation ALK inhibitors have demonstrated clinical activity in both crizotinib-refractory and crizotinib naïve setting. How to maximize first-line benefit for advanced ALK-positive NSCLC remains challenging. Combinational strategy, advances in companion diagnostics and optimization of ALK inhibitors might contribute to improve outcome in this subset of patients in future.

Role of the p55-gamma subunit of PI3K in ALK-induced cell migration: RNAi-based selection of cell migration regulators

Recently, unbiased functional genetic selection identified novel cell migration-regulating genes. This RNAi-based functional selection was performed using 63,996 pooled lentiviral shRNAs targeting 21,332 mouse genes. After five rounds of selection using cells with accelerated or impaired migration, shRNAs were retrieved and identified by half-hairpin barcode sequencing using cells with the selected phenotypes. This selection process led to the identification of 29 novel cell migration regulators. One of these candidates, anaplastic lymphoma kinase (ALK), was further investigated. Subsequent studies revealed that ALK promoted cell migration through the PI3K-AKT pathway via the p55γ regulatory subunit of PI3K, rather than more commonly used p85 subunit. Western blot and immunohistochemistry studies using mouse brain tissues revealed similar temporal expression patterns of ALK, phospho-p55γ, and phospho-AKT during different stages of development. These data support an important role for the p55γ subunit of PI3K in ALK-induced cell migration during brain development.

Cancer Drug Development Using Drosophila as an in vivo Tool: From Bedside to Bench and Back

The fruit fly Drosophila melanogaster has been used for modeling cancer and as an in vivo tool for the validation and/or development of cancer therapeutics. The impetus for the use of Drosophila in cancer research stems from the high conservation of its signaling pathways, lower genetic redundancy, short life cycle, genetic amenability, and ease of maintenance. Several cell signaling pathways in Drosophila have been used for cancer drug development. The efficacy of combination therapy and uptake/bioavailability of drugs have also been studied. Drosophila has been validated using several FDA-approved drugs, suggesting a potential application of this model in drug repurposing. The model is emerging as a powerful tool for high-throughput screening and should significantly reduce the cost and time associated with drug development. In this review we discuss the applications of Drosophila in cancer drug development. The advantages and limitations of the model are discussed.

ROS1 fusions in cancer: a review

The ROS1 gene belongs to the sevenless subfamily of tyrosine kinase insulin receptor genes. A literature review identified a ROS1 fusion in 2.54% of the patients with lung adenocarcinoma and even higher frequencies in spitzoid neoplasms and inflammatory myofibroblastic tumors. At present, 26 genes were found to fuse with ROS1, some of them already known to fuse with RET and ALK. All the fusion proteins retain the ROS1 kinase domain, but rarely its transmembrane domain. Most of the partners have dimerization domains that are retained in the fusion, presumably leading to constitutive ROS1 tyrosine kinase activation. Some partners have transmembrane domains that are retained or not in the chimeric proteins. Therefore, different ROS1 fusions have distinct subcellular localization, suggesting that they may activate different substrates in vivo.

Pyrazolylamine Derivatives Reveal the Conformational Switching between Type I and Type II Binding Modes of Anaplastic Lymphoma Kinase (ALK)

Most anaplastic lymphoma kinase (ALK) inhibitors adopt a type I binding mode, but only limited type II ALK structural studies are available. Herein, we present the structure of ALK in complex with N1-(3-4-[([5-(tert-butyl)-3-isoxazolyl]aminocarbonyl)amino]-3-methylphenyl-1H-5-pyrazolyl)-4-[(4-methylpiperazino)methyl]benzamide (5a), a novel ALK inhibitor adopting a type II binding mode. It revealed binding of 5a resulted in the conformational change and reposition of the activation loop, αC-helix, and juxtamembrane domain, which are all important domains for the autoinhibition mechanism and downstream signal pathway regulation of ALK. A structure-activity relationship study revealed that modifications to the structure of 5a led to significant differences in the ALK potency and altered the protein structure of ALK. To the best of our knowledge, this is the first structural biology study to directly observe how changes in the structure of a small molecule can regulate the switch between the type I and type II binding modes and induce dramatic conformational changes.

Safety profiles of first-line therapies for metastatic non-squamous non-small-cell lung cancer

INTRODUCTION

Lung cancer still represents the leading cause of death for cancer. About the 70% of diagnosis are in advanced-stage. Non-small-cell lung cancer (NSCLC) represents the 85% of all diagnosed lung cancers and non-squamous histology represents the 40% of all NSCLC. First-line therapies increase survival, control symptoms and improve quality of life, compared with best supportive care. It is crucial to choose a treatment with a low impact on patient's life considering the related toxicities.

AREAS COVERED

Adverse events (AEs) of first-line therapies for non-squamous NSCLC are here reviewed and discussed, from evidences in clinical trials conducting to drugs approval.

EXPERT OPINION

For advanced disease, palliation and preserving patients QoL are still the primary goal of treatment. Therefore, differing toxicity profiles are often a deciding factor in first-line and also maintenance setting for non-squamous NSCLC. Special attention is necessary to renal function and drugs' nephrotoxicity. Moreover, it is to consider the specific AEs of drugs classes: hypertension, bleeding, and proteinuria, for anti-VEGF therapy; skin toxicity, diarrhea, interstitial lung disease for TKIs; vision disorders, and hepatotoxicity for ALK-inhibitor. It is important to select patients for a treatment on the basis of their comorbidities and the presence of risk factors.

A new look at the ALK gene in cancer: copy number gain and amplification

To date, ALK-rearrangement is a molecular target in several cancers, i.e. NSCLC. The dramatic benefits of crizotinib have prompted research into identifying other possible patients carrying ALK gene alterations with possible clinical significance. The ALK gene is involved not only in several rearrangements but also in other alterations such as amplification. ALK-amplification (ALK-A) is a common genetic event in several cancers, generally associated with poor outcome and more aggressive behaviour. Here we review the role of ALK-A in cancer as a prognostic and predictive biomarker. Furthermore, several critical issues regarding ALK-A in relation to; methods of detection, acquired resistance and ALK second generation inhibitors are analyzed. We conclude that ALK-A could be an intriguing alteration in the context of targeted therapy.

Discovery of Low Micromolar Dual Inhibitors for Wild Type and L1196M Mutant of Anaplastic Lymphoma Kinase through Structure-Based Virtual Screening

Although anaplastic lymphoma kinase (ALK) is involved in a variety of malignant human cancers, the emergence of constitutively active mutants with drug resistance has rendered it difficult to identify the new medicines for ALK-dependent cancers. To find the common inhibitors of the wild type ALK and the most abundant drug-resistant mutant (L1196M), we performed molecular docking-based virtual screening of a large chemical library in parallel for the two target proteins. As a consequence of augmenting the accuracy of the docking simulation by implementing a sophisticated hydration free energy term in the scoring function, 12 common inhibitors are discovered with the inhibitory activities ranging from submicromolar to low micromolar levels. The results of the binding free energy decomposition indicate that the biochemical potency of ALK inhibitors can be optimized by reducing the dehydration cost for binding to the receptor protein as well as by strengthening the interactions with amino acid residues in the ATP-binding site. The newly identified ALK inhibitors are found to have a little higher inhibitory activity for the L1196M mutant than for the wild type due to the strengthening of the hydrogen bond interactions in the ATP-binding site. Of the 12 common inhibitors, 2-(5-methyl-benzooxazol-2-ylamino)-quinazolin-4-ol (3) is anticipated to serve as a new molecular scaffold to optimize the biochemical potency because it exhibits low micromolar inhibitory activity with respect to both the wild type and L1196M mutant in spite of the low molecular weight (292.3 amu).

Anticancer mechanisms of cannabinoids

In addition to the well-known palliative effects of cannabinoids on some cancer-associated symptoms, a large body of evidence shows that these molecules can decrease tumour growth in animal models of cancer. They do so by modulating key cell signalling pathways involved in the control of cancer cell proliferation and survival. In addition, cannabinoids inhibit angiogenesis and decrease metastasis in various tumour types in laboratory animals. In this review, we discuss the current understanding of cannabinoids as antitumour agents, focusing on recent discoveries about their molecular mechanisms of action, including resistance mechanisms and opportunities for their use in combination therapy. Those observations have already contributed to the foundation for the development of the first clinical studies that will analyze the safety and potential clinical benefit of cannabinoids as anticancer agents.

First-in-human, open-label dose-escalation and dose-expansion study of the safety, pharmacokinetics, and antitumor effects of an oral ALK inhibitor ASP3026 in patients with advanced solid tumors

BACKGROUND

ASP3026 is a second-generation anaplastic lymphoma kinase (ALK) inhibitor that has potent in vitro activity against crizotinib-resistant ALK-positive tumors. This open-label, multicenter, first-in-human phase I study ( NCT01284192 ) assessed the safety, pharmacokinetic profile, and antitumor activity of ASP3026.

METHODS

Advanced solid tumor patients received oral ASP3026 in 3 + 3 dose-escalation cohorts at doses of 25-800 mg once daily in 28-day cycles. The endpoints were to identify the maximum tolerated dose (MTD), the recommended phase II dose (RP2D), and the pharmacokinetic profile of ASP3026. A phase Ib expansion cohort enrolled patients with metastatic, crizotinib-resistant ALK-positive solid tumors at the RP2D, and response was evaluated by RECIST 1.1.

RESULTS

The dose-escalation cohort enrolled 33 patients, including three crizotinib-resistant, ALK-positive patients, and the dose-expansion cohort enrolled another 13 crizotinib-resistant, ALK-positive non-small cell lung cancer (NSCLC) patients. ASP3026 demonstrated both linear pharmacokinetics and dose-proportional exposure for area under the plasma concentration-time curve and maximum concentration observed with a median terminal half-life of 35 h, supporting the daily dosing. Grade 3 rash and elevated transaminase concentrations were dose-limiting toxicities observed at 800 mg; hence, 525 mg daily was the MTD and RP2D. The most common treatment-related adverse events were nausea (38%), fatigue (35%), and vomiting (35 %). Among the 16 patients with crizotinib-resistant ALK-positive tumors (15 NSCLC, 1 neuroblastoma), eight patients achieved partial response (overall response rate 50%; 95% confidence interval 25-75%) and seven patients (44%) achieved stable disease.

CONCLUSIONS

ASP3026 was well tolerated and had therapeutic activity in patients with crizotinib-resistant ALK-positive advanced tumors.

TRIAL REGISTRATION

ClinTrials.gov: NCT01284192.

EGFR, ALK, RET, KRAS and BRAF alterations in never-smokers with non-small cell lung cancer

Non-small cell lung cancer (NSCLC), caused by various mutations in a spectrum of cancer driver genes, may have distinct pathological characteristics and drug responses. Extensive genetic screening and pathological characterization is required for the design of customized therapies to improve patient outcomes. Notably, NSCLC in never-smokers exhibits distinctive clinicopathological features, which are frequently associated with tumorigenic mutations, and thus may be treated as a unique disease entity. However, to the best of our knowledge, these mutations have not been extensively and accurately characterized in an NSCLC study with a large sample size. Therefore, the present study enrolled a large cohort of NSCLC patients, which consisted of 358 never-smokers, for the screening of genetic alterations in the epidermal growth factor receptor (EGFR), ret proto-oncogene (RET), anaplastic lymphoma kinase (ALK), Kirsten rat sarcoma viral oncogene homolog (KRAS) and B-Raf proto-oncogene serine/threonine kinase (BRAF) tumorigenic genes. It was identified that the mutation rate was 47.8, 7.5, 3.6, 1.4 and 0.3% for EGFR, ALK, KRAS, RET and BRAF, respectively. In addition, clinicopathological features associated with these mutations were characterized. EGFR mutations were more frequently observed in female and older patients. By contrast, KRAS mutations were more frequently detected in male patients, and ALK and RET translocations in younger patients. The cancer cells were frequently well-differentiated in carcinoma cases exhibiting EGFR mutations, however, were less differentiated in those with ALK translocations. In conclusion, the present study determined the frequency of oncogenic alterations and associated clinicopathological features in NSCLC exhibited by never-smokers using a large sample size. The results of the present study may enrich our knowledge of NSCLC in never-smokers and provide useful insights for improvement of the outcome of molecularly targeted therapies for the treatment of NSCLC.

The use of cannabinoids as anticancer agents

It is well-established that cannabinoids exert palliative effects on some cancer-associated symptoms. In addition evidences obtained during the last fifteen years support that these compounds can reduce tumor growth in animal models of cancer. Cannabinoids have been shown to activate an ER-stress related pathway that leads to the stimulation of autophagy-mediated cancer cell death. In addition, cannabinoids inhibit tumor angiogenesis and decrease cancer cell migration. The mechanisms of resistance to cannabinoid anticancer action as well as the possible strategies to develop cannabinoid-based combinational therapies to fight cancer have also started to be explored. In this review we will summarize these observations (that have already helped to set the bases for the development of the first clinical studies to investigate the potential clinical benefit of using cannabinoids in anticancer therapies) and will discuss the possible future avenues of research in this area.

Anaplastic Lymphoma Kinase Acts in the Drosophila Mushroom Body to Negatively Regulate Sleep

Though evidence is mounting that a major function of sleep is to maintain brain plasticity and consolidate memory, little is known about the molecular pathways by which learning and sleep processes intercept. Anaplastic lymphoma kinase (Alk), the gene encoding a tyrosine receptor kinase whose inadvertent activation is the cause of many cancers, is implicated in synapse formation and cognitive functions. In particular, Alk genetically interacts with Neurofibromatosis 1 (Nf1) to regulate growth and associative learning in flies. We show that Alk mutants have increased sleep. Using a targeted RNAi screen we localized the negative effects of Alk on sleep to the mushroom body, a structure important for both sleep and memory. We also report that mutations in Nf1 produce a sexually dimorphic short sleep phenotype, and suppress the long sleep phenotype of Alk. Thus Alk and Nf1 interact in both learning and sleep regulation, highlighting a common pathway in these two processes.

Crizotinib-induced antitumour activity in human alveolar rhabdomyosarcoma cells is not solely dependent on ALK and MET inhibition

Background

Rhabdomyosarcoma (RMS) is the most commonly diagnosed malignant soft tissue tumour in children and adolescents. Aberrant expression of Anaplastic Lymphoma Kinase (ALK) and MET gene has been implicated in the malignant progression of RMS, especially in the alveolar subtype. This observation suggests that crizotinib (PF-02341066), a kinase inhibitor against ALK and MET, may have a therapeutic role in RMS, although its antitumour activity in this malignancy has not yet been studied.

Methods

RH4 and RH30 alveolar RMS (ARMS) cell lines were treated with crizotinib and then assessed by using proliferation, viability, migration and colony formation assays. Multiple approaches, including flow cytometry, immunofluorescence, western blotting and siRNA-based knock-down, were used in order to investigate possible molecular mechanisms linked to crizotinib activity.

Results

In vitro treatment with crizotinib inhibited ALK and MET proteins, as well as Insulin-like Growth Factor 1 Receptor (IGF1R), with a concomitant robust dephosphorylation of AKT and ERK, two downstream kinases involved in RMS cell proliferation and survival. Exposure to crizotinib impaired cell growth, and accumulation at G2/M phase was attributed to an altered expression and activation of checkpoint regulators, such as Cyclin B1 and Cdc2. Crizotinib was able to induce apoptosis and autophagy in a dose-dependent manner, as shown by caspase-3 activation/PARP proteolytic cleavage down-regulation and by LC3 activation/p62 down-regulation, respectively. The accumulation of reactive oxygen species (ROS) seemed to contribute to crizotinib effects in RH4 and RH30 cells. Moreover, crizotinib-treated RH4 and RH30 cells exhibited a decreased migratory/invasive capacity and clonogenic potential.

Conclusions

These results provide a further insight into the molecular mechanisms affected by crizotinib in ARMS cells inferring that it could be a useful therapeutic tool in ARMS cancer treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0228-4) contains supplementary material, which is available to authorized users.

The distinctive nature of adenocarcinoma of the lung

In recent years, many personalized treatments have been developed for NSCLC (non-small-cell lung cancer) patients. Among these, gefitinib, erlotinib, and afatinib are selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors for patients with EGFR gene mutations, while crizotinib and ceritinib are two new tyrosine kinase inhibitors directed against the echinoderm microtubule-like protein 4-anaplastic lymphoma kinase translocation. The possibility of these new molecules being used to treat patients without adenocarcinoma histology is notably small. For example, EGFR mutations and anaplastic lymphoma kinase fusion gene rearrangement are rare in patients with squamous cell carcinoma (generally <1%). Additionally, the benefit of targeted treatment approaches in patients with small-cell lung cancer histology is limited. All of these findings highlight the distinctive nature of adenocarcinoma of the lung among all lung cancer subtypes. Unfortunately, to date, less than 15% of patients with adenocarcinoma of the lung are ideal candidates for these targeted therapies.

Therapeutically Targetable ALK Mutations in Leukemia

Genome sequencing is revealing a vast mutational landscape in leukemia, offering new opportunities for treatment with targeted therapy. Here, we identify two patients with acute myelogenous leukemia and B-cell acute lymphoblastic leukemia whose tumors harbor point mutations in the ALK kinase. The mutations reside in the extracellular domain of ALK and are potently transforming in cytokine-independent cellular assays and primary mouse bone marrow colony formation studies. Strikingly, both mutations conferred sensitivity to ALK kinase inhibitors, including the FDA-approved drug crizotinib. On the basis of our results, we propose that tumors harboring ALK mutations may be therapeutically tractable for personalized treatment of certain aggressive leukemias with ALK inhibitors.

Ethanol activates midkine and anaplastic lymphoma kinase signaling in neuroblastoma cells and in the brain

Alcohol engages signaling pathways in the brain. Midkine (MDK) is a neurotrophic factor that is over-expressed in the prefrontal cortex of alcoholics. MDK and one of its receptors, anaplastic lymphoma kinase (ALK), also regulate behavioral responses to ethanol in mice. The goal of this study was to determine whether MDK and ALK expression and signaling are activated by ethanol. We found that ethanol treatment of neuroblastoma cells increased MDK and ALK expression. We also assessed activation of ALK by ethanol in cells and found that ALK and ALK-dependent extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3) phosphorylation increased rapidly with ethanol exposure. Similarly, treatment of cells with recombinant MDK protein increased ALK, ERK and STAT3 phosphorylation, suggesting that ethanol may utilize MDK to activate ALK signaling. In support of this, transfection of cells with MDK siRNAs attenuated ALK signaling in response to ethanol. Ethanol also activates ERK signaling in the brain. We found that inhibition of ALK or knockout of MDK attenuated ethanol-induced ERK phosphorylation in mouse amygdala. These results demonstrate that ethanol engages MDK and ALK signaling, which has important consequences for alcohol-induced neurotoxicity and the regulation of behaviors related to alcohol abuse.

The Structural Characterization of Tumor Fusion Genes and Proteins

Chromosomal translocation, which generates fusion proteins in blood tumor or solid tumor, is considered as one of the major causes leading to cancer. Recent studies suggested that the disordered fragments in a fusion protein might contribute to its carcinogenicity. Here, we investigated the sequence feature near the breakpoints in the fusion partner genes, the structure features of breakpoints in fusion proteins, and the posttranslational modification preference in the fusion proteins. Results show that the breakpoints in the fusion partner genes have both sequence preference and structural preference. At the sequence level, nucleotide combination AG is preferred before the breakpoint and GG is preferred at the breakpoint. At the structural level, the breakpoints in the fusion proteins prefer to be located in the disordered regions. Further analysis suggests the phosphorylation sites at serine, threonine, and the methylation sites at arginine are enriched in disordered regions of the fusion proteins. Using EML4-ALK as an example, we further explained how the fusion protein leads to the protein disorder and contributes to its carcinogenicity. The sequence and structural features of the fusion proteins may help the scientific community to predict novel breakpoints in fusion genes and better understand the structure and function of fusion proteins.

Clinicopathologic characteristics and therapeutic responses of Chinese patients with non-small cell lung cancer who harbor an anaplastic lymphoma kinase rearrangement

INTRODUCTION

The rearrangement of the anaplastic lymphoma kinase (ALK) gene accounts for approximately 1%-6% of lung adenocarcinoma cases and defines a molecular subgroup of tumors characterized by clinical sensitivity to ALK inhibitors such as crizotinib. This study aimed to identify the relationship between ALK rearrangement and the clinicopathologic characteristics of non-small cell lung cancer (NSCLC) and to analyze the therapeutic responses of crizotinib and conventional chemotherapy to ALK rearrangement in NSCLC patients.

METHODS

A total of 487 lung cancer patients who underwent testing for ALK rearrangement in our department were included in this study. ALK rearrangement was examined by using fluorescence in situ hybridization (FISH) assay.

RESULTS

Among the 487 patients, 44 (9.0%) were diagnosed with ALK rearrangement by using FISH assay. In 123 patients with adenocarcinoma who were non-smokers and of a young age (≤ 58 years old), the frequency of ALK rearrangement was 20.3% (25/123). Short overall survival (OS) was associated with non-adenocarcinoma tumor type (P = 0.006), poorly differentiated tumors (P = 0.001), advanced-stage tumors (P < 0.001), smoking history (P = 0.008), and wild-type epidermal growth factor receptor (EGFR) (P = 0.008). Moreover, patients with poorly differentiated and advanced-stage tumors had a shorter time to cancer progression compared with those with well differentiated (P = 0.023) and early-stage tumors (P = 0.001), respectively.

CONCLUSIONS

ALK-rearranged NSCLC tends to occur in younger individuals who are either non-smokers or light smokers with adenocarcinoma. Patients with ALK rearrangement might benefit from ALK inhibitor therapy.

The role of intracellular calcium for the development and treatment of neuroblastoma

Neuroblastoma is the second most common paediatric cancer. It developsfrom undifferentiated simpatico-adrenal lineage cells and is mostly sporadic; however, theaetiology behind the development of neuroblastoma is still not fully understood. Intracellularcalcium ([Ca2+]i) is a secondary messenger which regulates numerous cellular processesand, therefore, its concentration is tightly regulated. This review focuses on the role of[Ca2+]i in differentiation, apoptosis and proliferation in neuroblastoma. It describes themechanisms by which [Ca2+]i is regulated and how it modulates intracellular pathways.Furthermore, the importance of [Ca2+]i for the function of anti-cancer drugs is illuminatedin this review as [Ca2+]i could be a target to improve the outcome of anti-cancer treatmentin neuroblastoma. Overall, modulations of [Ca2+]i could be a key target to induce apoptosisin cancer cells leading to a more efficient and effective treatment of neuroblastoma.

Peptides derived from the dependence receptor ALK are proapoptotic for ALK-positive tumors

ALK is a receptor tyrosine kinase with an oncogenic role in various types of human malignancies. Despite constitutive activation of the kinase through gene alterations, such as chromosomal translocation, gene amplification or mutation, treatments with kinase inhibitors invariably lead to the development of resistance. Aiming to develop new tools for ALK targeting, we took advantage of our previous demonstration identifying ALK as a dependence receptor, implying that in the absence of ligand the kinase-inactive ALK triggers or enhances apoptosis. Here, we synthesized peptides mimicking the proapoptotic domain of ALK and investigated their biological effects on tumor cells. We found that an ALK-derived peptide of 36 amino acids (P36) was cytotoxic for ALK-positive anaplastic large-cell lymphoma and neuroblastoma cell lines. In contrast, ALK-negative tumor cells and normal peripheral blood mononuclear cells were insensitive to P36. The cytotoxic effect was due to caspase-dependent apoptosis and required N-myristoylation of the peptide. Two P36-derived shorter peptides as well as a cyclic peptide also induced apoptosis. Surface plasmon resonance and mass spectrometry analysis of P36-interacting proteins from two responsive cell lines, Cost lymphoma and SH-SY5Y neuroblastoma, uncovered partners that could involve p53-dependent signaling and pre-mRNA splicing. Furthermore, siRNA-mediated knockdown of p53 rescued these cells from P36-induced apoptosis. Finally, we observed that a treatment combining P36 with the ALK-specific inhibitor crizotinib resulted in additive cytotoxicity. Therefore, ALK-derived peptides could represent a novel targeted therapy for ALK-positive tumors.