Notch ligand Delta-like 1 as a novel molecular target in childhood neuroblastoma

Abstract

BackgroundNeuroblastoma is the most common extracranial solid malignancy in childhood, responsible for 15% of all pediatric cancer deaths. It is an heterogeneous disease that does not always respond to classical therapy; so the identification of new and specific molecular targets to improve existing therapy is needed. We have previously demonstrated the involvement of the Notch pathway in the onset and progression of neuroblastoma. In this study we further investigated the role of Notch signaling and identified Delta-like 1 (DLL1) as a novel molecular target in neuroblastoma cells with a high degree of MYCN amplification, which is a major oncogenic driver in neuroblastoma. The possibility to act on DLL1 expression levels by using microRNAs (miRNAs) was assessed.MethodsDLL1 mRNA and protein expression levels were measured in three different neuroblastoma cell lines using quantitative real-time PCR and Western Blot analysis, respectively. Activation of the Notch pathway as a result of increased levels of DLL1 was analyzed by Immunofluorescence and Western Blot methods. In silico tools revealed the possibility to act on DLL1 expression levels with miRNAs, in particular with the miRNA-34 family. Neuroblastoma cells were transfected with miRNA-34 family members, and the effect of miRNAs transfection on DLL1 mRNA expression levels, on cell differentiation, proliferation and apoptosis was measured.ResultsIn this study, the DLL1 ligand was identified as the Notch pathway component highly expressed in neuroblastoma cells with MYCN amplification. In silico analysis demonstrated that DLL1 is one of the targets of miRNA-34 family members that maps on chromosome regions that are frequently deregulated or deleted in neuroblastoma. We studied the possibility to use miRNAs to target DLL1. Among all miRNA-34 family members, miRNA-34b is able to significantly downregulate DLL1 mRNA expression levels, to arrest cell proliferation and to induce neuronal differentiation in malignant neuroblastoma cells.ConclusionsTargeted therapies have emerged as new strategies for cancer treatment. This study identified the Notch ligand DLL1 as a novel and attractive molecular target in childhood neuroblastoma and its results could help to devise a targeted therapy using miRNAs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-017-3340-3) contains supplementary material, which is available to authorized users.

Defining the relative and combined contribution of CTCF and CTCFL to genomic regulation

“…2f). DLL1 is a Notch ligand known to play a major role in cancers like breast cancer [47,48] and squamous neoplasias [49], and it is thought to be a promising therapeutic target [50]. Our ChIP-seq data showed CTCFL binding at the promoter of Dll1 and other CTAs such as TSP50 or Prss50 [51] and those belonging to the MAGE family (MAGE-B4, MAGE-E1, MAGE-F1) (Additional file 1: Figure S3A, B).…”

The Notch ligand DLL1 exerts carcinogenic features in human breast cancer cells

“…For example, DLL1 expression is significantly higher in oligodendrogliomas than in normal brain cells and is associated with glioma cell proliferation and survival [23]. In childhood neuroblastomas with MYCN gene amplification, DLL1 is highly expressed and implicated in the onset of this type of cancer by promoting cell proliferation and maintaining their undifferentiated status [37]. In multiple myeloma, DLL1-mediated Notch activation has been shown to increase cell proliferation, promote clonogenic growth in vitro , accelerate tumor growth initiation [20], and contribute to drug resistance [38].…”

Favorable prognostic role of tropomodulins in neuroblastoma

“…Our previous study identified Notch pathway as one of the molecular pathways involved in the onset and progression of neuroblastoma [ 6 ]. In particular, we recognized Notch ligand DLL1 as the specific molecular target in childhood neuroblastoma and we proposed miRNAs as novel therapeutic tool to attack “DLL1 positive” neuroblastoma [ 7 ]. The challenge is to identify innovative and selective biomarkers to better understand clinical and molecular mechanisms underlying neuroblastoma progression and to devise new personalized therapeutics opportunities.…”