High expression of β-catenin contributes to the crizotinib resistant phenotype in the stem-like cell population in neuroblastoma

Bioinformatics analysis of miRNAs in the neuroblastoma 11q-deleted region reveals a role of miR-548l in both 11q-deleted and MYCN amplified tumour cells

Neuroblastoma is a childhood tumour that is responsible for approximately 15% of all childhood cancer deaths. Neuroblastoma tumours with amplification of the oncogene MYCN are aggressive, however, another aggressive subgroup without MYCN amplification also exists; rather, they have a deleted region at chromosome arm 11q. Twenty-six miRNAs are located within the breakpoint region of chromosome 11q and have been checked for a possible involvement in development of neuroblastoma due to the genomic alteration. Target genes of these miRNAs are involved in pathways associated with cancer, including proliferation, apoptosis and DNA repair. We could show that miR-548l found within the 11q region is downregulated in neuroblastoma cell lines with 11q deletion or MYCN amplification. In addition, we showed that the restoration of miR-548l level in a neuroblastoma cell line led to a decreased proliferation of these cells as well as a decrease in the percentage of cells in the S phase. We also found that miR-548l overexpression suppressed cell viability and promoted apoptosis, while miR-548l knockdown promoted cell viability and inhibited apoptosis in neuroblastoma cells. Our results indicate that 11q-deleted neuroblastoma and MYCN amplified neuroblastoma coalesce by downregulating miR-548l.

Correlation of Immunological and Molecular Profiles with Response to Crizotinib in Alveolar Soft Part Sarcoma: An Exploratory Study Related to the EORTC 90101 "CREATE" Trial

Alveolar soft part sarcoma (ASPS) is a rare subtype of soft tissue sarcoma characterized by an unbalanced translocation, resulting in ASPSCR1-TFE3 fusion that transcriptionally upregulates MET expression. The European Organization for Research and Treatment of Cancer (EORTC) 90101 “CREATE” phase II trial evaluated the MET inhibitor crizotinib in ASPS patients, achieving only limited antitumor activity. We performed a comprehensive molecular analysis of ASPS tissue samples collected in this trial to identify potential biomarkers correlating with treatment outcome. A tissue microarray containing 47 ASPS cases was used for the characterization of the tumor microenvironment using multiplex immunofluorescence. DNA isolated from 34 available tumor samples was analyzed to detect recurrent gene copy number alterations (CNAs) and mutations by low-coverage whole-genome sequencing and whole-exome sequencing. Pathway enrichment analysis was used to identify diseased-associated pathways in ASPS sarcomagenesis. Kaplan–Meier estimates, Cox regression, and the Fisher’s exact test were used to correlate histopathological and molecular findings with clinical data related to crizotinib treatment, aiming to identify potential factors associated with patient outcome. Tumor microenvironment characterization showed the presence of PD-L1 and CTLA-4 in 10 and 2 tumors, respectively, and the absence of PD-1 in all specimens. Apart from CD68, other immunological markers were rarely expressed, suggesting a low level of tumor-infiltrating lymphocytes in ASPS. By CNA analysis, we detected a number of broad and focal alterations. The most common alteration was the loss of chromosomal region 1p36.32 in 44% of cases. The loss of chromosomal regions 1p36.32, 1p33, 1p22.2, and 8p was associated with shorter progression-free survival. Using whole-exome sequencing, 13 cancer-associated genes were found to be mutated in at least three cases. Pathway enrichment analysis identified genetic alterations in NOTCH signaling, chromatin organization, and SUMOylation pathways. NOTCH4 intracellular domain dysregulation was associated with poor outcome, while inactivation of the beta-catenin/TCF complex correlated with improved outcome in patients receiving crizotinib. ASPS is characterized by molecular heterogeneity. We identify genetic aberrations potentially predictive of treatment outcome during crizotinib therapy and provide additional insights into the biology of ASPS, paving the way to improve treatment approaches for this extremely rare malignancy.

Extracellular domain shedding of the ALK receptor mediates neuroblastoma cell migration

Although activating mutations of the anaplastic lymphoma kinase (ALK) membrane receptor occur in ~10% of neuroblastoma (NB) tumors, the role of the wild-type (WT) receptor, which is aberrantly expressed in most non-mutated cases, is unclear. Both WT and mutant proteins undergo extracellular domain (ECD) cleavage. Here, we map the cleavage site to Asn654-Leu655 and demonstrate that cleavage inhibition of WT ALK significantly impedes NB cell migration with subsequent prolongation of survival in mouse models. Cleavage inhibition results in the downregulation of an epithelial-to-mesenchymal transition (EMT) gene signature, with decreased nuclear localization and occupancy of β-catenin at EMT gene promoters. We further show that cleavage is mediated by matrix metalloproteinase 9, whose genetic and pharmacologic inactivation inhibits cleavage and decreases NB cell migration. Together, our results indicate a pivotal role for WT ALK ECD cleavage in NB pathogenesis, which may be harnessed for therapeutic benefit.

Huang et al. show that extracellular domain (ECD) cleavage of the ALK cell surface tyrosine kinase receptor mediates neuroblastoma cell migration through induction of an EMT phenotype. ECD cleavage is caused by MMP-9 whose inhibition leads to decreased cell migration.

Long Noncoding RNA NHEG1 Drives β-Catenin Transactivation and Neuroblastoma Progression through Interacting with DDX5

Recent studies suggest that long noncoding RNAs (lncRNAs) play essential roles in tumor progression. However, the functional roles and underlying mechanisms of lncRNAs in neuroblastoma (NB), the most common malignant solid tumor in pediatric population, still remain elusive. Herein, through integrating analysis of a public RNA sequencing dataset, neuroblastoma highly expressed 1 (NHEG1) was identified as a risk-associated lncRNA, contributing to an unfavorable outcome of NB. Depletion of NHEG1 led to facilitated differentiation and decreased growth and aggressiveness of NB cells. Mechanistically, NHEG1 bound to and stabilized DEAD-box helicase 5 (DDX5) protein through repressing proteasome-mediated degradation, resulting in β-catenin transactivation that altered target gene expression associated with NB progression. We further determined a lymphoid enhancer binding factor 1 (LEF1)/transcription factor 7-like 2 (TCF7L2)/NHEG1/DDX5/β-catenin axis with a positive feedback loop and demonstrated that NHEG1 harbored oncogenic properties via its interplay with DDX5. Administration of small interfering RNAs against NHEG1 or DDX5 reduced tumor growth and prolonged survival of nude mice bearing xenografts. High NHEG1 or DDX5 expression was associated with poor survival of NB patients. These results indicate that lncRNA NHEG1 exhibits oncogenic activity that affects NB progression via stabilizing the DDX5 protein, which might serve as a potential therapeutic target for NB.

The role of β-catenin and paired-like homeobox 2B (PHOX2B) expression in neuroblastoma patients; predictive and prognostic value

BACKGROUND

The expression of β-catenin and paired-like homeobox 2B (PHOX2B) expression were assessed in Neuroblastoma (NB) patients as a diagnostic, prognostic and/or predictive markers.

METHODS

Bone marrow (BM) samples of 52 NB patients were assessed for the expression of β-catenin by immunohistochemistry (IHC), and PHOX2B by real time PCR (RT-PCR), compared to 12 healthy normal controls (NC). The data were correlated to the clinic-pathological features of the patients, response to treatment and disease relapse.

RESULTS

β-catenin was expressed in 40 (76.92%) patients (P < .001). While PHOX2B was expressed in 32/52 (61.5%) patients, with a fold change of 0.29 (0.01-40.0, P = .096). β-catenin expression associated significantly with advanced tumor stage, high risk, positive results by MIBG and bone scan (P = .002, P < .001, P = .006, P = .013; respectively). Also it associated significantly with synaptophysin expression in the BM biopsy (P < .001), with a significant concordance (K = 0.519, P < .001). The expression of β-catenin associated significantly with PHOX2B gene expression [28/32 (87.5%), P = .04], and its fold change (P = .027), with a significant measure of agreement (K = 0.297, P = .022). The fold change of PHOX2B gene expression associated significantly with the high risk of the patients (P = .04). Poor response to treatment associated significantly with the expression of neuron specific enolase (NSE), β-catenin and PHOX2B in NB patients (P = .021, P = .019 and P = .040; respectively). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of synaptophysin for the diagnosis of BM metastasis in NB patients were (69%, 65.2%, 71.4%, 62.5%; respectively, P = .024). While with β-catenin (93.1%, 43.5%, 67.5%, 83.3%; respectively, P = .003), and PHOX2B expression (65.5%, 34.5%, 59.4%, 50%; respectively, P = .574).

CONCLUSION

β-Catenin could be used as a sensitive and reliable marker for detection of BM metastasis and also a good predictor for resistance to treatment in NB patients. While, PHOX2B gene expression in BM aspirate could be a marker for high risk patients and poor response to treatment.

p53 and β-Catenin Expression Predict Poorer Prognosis in Patients With Anaplastic Large-Cell Lymphoma

BACKGROUND

The Wnt/β-catenin signaling pathway is a major target of p53. β-Catenin/p53 coexpression predicts poorer survival in carcinoma patients. Conversely, CD99 inhibits tumor metastasis through the Wnt/β-catenin pathway. We therefore assessed p53, β-catenin, and CD99 by immunohistochemistry.

PATIENTS AND METHODS

We studied 45 patients with systemic anaplastic large-cell lymphoma (ALCL), including 20 anaplastic lymphoma kinase (ALK)-positive and 25 ALK-negative ALCL. β-Catenin expression was analyzed using phospho-β-catenin-S552 antibody because its nuclear localization indicates Wnt signaling.

RESULTS

In this cohort, p53 expression was associated with ALK-negative ALCL. Furthermore, p53 or β-catenin expression alone or β-catenin/p53 double expression showed poorer overall survival and disease-free survival in patients with ALCL overall and in patients with ALK-negative ALCL. CD99 expression was more frequent in ALK-positive ALCL but had no prognostic significance.

CONCLUSION

This is the first study to evaluate phospho-β-catenin-S552 expression in ALCL. The results of this study, although limited by small patient size, suggest that β-catenin and p53 may play a role in pathogenesis and may be helpful in risk stratification of ALCL patients.

Role of the Anaplastic Lymphoma Kinase Inhibitor Crizotinib in the Management of Neuroblastoma

Neuroblastoma (NB) is a common extra-cranial solid malignancy of childhood. NB displays several clinical and biological features as well as many indeterminate aspects. Studies attempting to determine a prognostic factor in NB have been performed for a long time. Recent studies have focused on the anaplastic lymphoma kinase (ALK) gene. ALK mutations are one of the most prevalent and important biological disorders in NB. The presence of ALK mutations contributes to a more malignant character in NB. However, there is a limited number of studies on the clinical relevance of the expression of ALK or of its mutations. Th e elucidation of gene expression analyses in ALK can guide in the identification of risk groups and selection of treatment protocols. There is a need for further studies, as it is important to define patients eligible for use of ALK inhibitors.

Hypoxia Induces the Acquisition of Cancer Stem-like Phenotype Via Upregulation and Activation of Signal Transducer and Activator of Transcription-3 (STAT3) in MDA-MB-231, a Triple Negative Breast Cancer Cell Line

The finding that hypoxia can induce cancer stemness in various experimental models is in agreement with the conceptual basis of cancer cell plasticity. Here, we aimed to gain insights into the molecular basis of hypoxia-induced cancer cell plasticity in triple negative breast cancer (TNBC). To achieve this goal, we employed our previously published in-vitro model of TNBC, in which a small subset of stem-like cells can be distinguished from the bulk cell population based on their responsiveness to a Sox2 reporter. In MDA-MB-231, a TNBC cell line, we observed that hypoxia significantly increased the expression of luciferase and green fluorescence protein (GFP), the readouts of the Sox2 reporter. Upon hypoxic challenge, the bulk, reporter unresponsive (RU) cells acquired stem-like features, as evidenced by the significant increases in the proportion of CD44^high/CD24^low cells, colony formation and resistance to cisplatin. Correlating with these phenotypic changes, RU cells exposed to hypoxia exhibited a substantial upregulation of the active/phosphorylated form of STAT3 (pSTAT3). This hypoxia-induced activation of STAT3 correlated with increased STAT3 transcriptional activity, as evidenced by increased STAT3-DNA binding and an altered gene expression profile. This hypoxia-induced STAT3 activation is biologically significant, since siRNA knockdown of STAT3 in RU cells significantly attenuated the hypoxia-induced acquisition of Sox2 activity and stem-like phenotypic features. In conclusion, our data have provided the proof-of-concept that STAT3 is a critical mediator in promoting the hypoxia-induced acquisition of cancer stemness in TNBC. Targeting STAT3 in TNBC may be useful in overcoming chemoresistance and decreasing the risk of disease relapse.

lincROR influences the stemness and crizotinib resistance in EML-ALK+ non-small-cell lung cancer cells

Introduction

Echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) is identified as an important pathogenic factor in patients with non-small-cell lung cancer (NSCLC) and could induce a stem-like phenotype in NSCLC cells. Crizotinib is commonly used for EML4-ALK⁺ NSCLC treatment, but its acquired resistance results in tumor recurrence. Long intergenic noncoding RNA, regulator of reprogramming (lincROR) is related to the acquisition and maintenance of self-renewal and stemness features of cancer stem cells. It has been documented that lincROR is implicated in chemoresistance. However, the correlations of lincROR and EML4-ALK in stem cell-like properties and of lincROR and crizotinib resistance in NSCLC cells are yet to be elucidated.

Patients and methods

In the present study, we investigated the expression profile of lincROR in EML-ALK NSCLC tissues, and the potential role of lincROR in prognosis was then analyzed. Subsequently, its association with stem cell-like properties of EML-ALK⁺ NSCLC cells was determined. Furthermore, the correlation of lincROR with crizotinib and the effects of lincROR and crizotinib on cell viability of EML4-ALK⁺ NSCLC cells were all explored.

Results

The results showed that lincROR expression was upregulated in EML4-ALK⁺ NSCLC tissues relative to EML4-ALK^- NSCLC tissues. Low-expressed lincROR was related to a favorable prognosis of patients with EML-ALK NSCLC. lincROR overexpression could enhance the stemness features of EML-ALK⁺ NSCLC cells which were repressed by ALK knockdown.

Conclusion

We found that lincROR expression was significantly inhibited because of the increased concentration of crizotinib in EML4-ALK⁺ NSCLC cells. Furthermore, lincROR overexpression increased cell viability of EML4-ALK⁺ NSCLC cells, which was impaired by crizotinib. Conjointly, these results suggested the important role of lincROR in EML-ALK⁺ NSCLC. lincROR may serve as a potential therapeutic target to overcome chemotherapy resistance in EML-ALK⁺ NSCLC.