Journal Article

miR‐15a‐5p, miR‐15b‐5p, and miR‐16‐5p inhibit tumor progression by directly targeting MYCN in neuroblastoma

Poluektova, Larisa Y., Gorantla, Santhi, Coulter, Don W., Gupta, Subash C., Pandey, Manoj K., Pathania, Anup S., Challagundla, Kishore B., Chava, Srinivas, Reynolds, C. Patrick

2020

Overview

Neuroblastoma (NB) is the most common extracranial solid malignancy in children. Despite current aggressive treatment regimens, the prognosis for high‐risk NB patients remains poor, with the survival of less than 40%. Amplification/stabilization of MYCN oncogene, in NB is associated with a high risk of recurrence. Thus, there is an urgent need for novel therapeutics. The deregulated expression of microRNA (miR) is reported in NB; nonetheless, its effect on MYCN regulation is poorly understood. First, we identified that miR‐15a‐5p, miR‐15b‐5p, and miR‐16‐5p (hereafter miR‐15a, miR‐15b or miR‐16) were down‐regulated in patient‐derived xenografts (PDX) with high MYCN expression. MiR targeting sequences on MYCN mRNA were predicted using online databases such as TargetScan and miR database. The R2 database, containing 105 NB patients, showed an inverse correlation between MYCN mRNA and deleted in lymphocytic leukemia (DLEU) 2, a host gene of miR‐15. Moreover, overexpression of miR‐15a, miR‐15b or miR‐16 significantly reduced the levels of MYCN mRNA and N‐Myc protein. Conversely, inhibiting miR dramatically enhanced MYCN mRNA and N‐Myc protein levels, as well as increasing mRNA half‐life in NB cells. By performing immunoprecipitation assays of argonaute‐2 (Ago2), a core component of the RNA‐induced silencing complex, we showed that miR‐15a, miR‐15b and miR‐16 interact with MYCN mRNA. Luciferase reporter assays showed that miR‐15a, miR‐15b and miR‐16 bind with 3’UTR of MYCN mRNA, resulting in MYCN suppression. Moreover, induced expression of miR‐15a, miR‐15b and miR‐16 significantly reduced the proliferation, migration, and invasion of NB cells. Finally, transplanting miR‐15a‐, miR‐15b‐ and miR‐16‐expressing NB cells into NSG mice repressed tumor formation and MYCN expression. These data suggest that miR‐15a, miR‐15b and miR‐16 exert a tumor‐suppressive function in NB by targeting MYCN. Therefore, these miRs could be considered as potential targets for NB treatment. A model summarizing how miR‐15a, miR‐15b, and miR‐16 suppress tumor progression in neuroblastoma by targeting MYCN. When miRs are overexpressed, argonaute‐2‐mediated interaction of miR with MYCN mRNA increases, followed by degradation of MYCN, leading to neuroblastoma regression.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: 3' Untranslated Regions / Ago2 / Animals / Argonaute 2 protein / Argonaute Proteins - metabolism / Cancer / Cancer therapies / Care and treatment / Cell Line, Tumor / Cell Movement - genetics / Cell proliferation / Cell Survival - genetics / Chemotherapy / Databases, Genetic / Down-Regulation / Families & family life / Gene expression / Gene Expression Regulation, Neoplastic - genetics / Heterografts - metabolism / Humans / Immunoprecipitation / Laboratories / Leukemia / Lymphatic leukemia / Malignancy / Medical prognosis / Mice / Mice, Inbred NOD / Mice, Nude / MicroRNA / MicroRNAs / MicroRNAs - genetics / MicroRNAs - metabolism / miRNA / mRNA / Myc protein / MYCN / N-Myc Proto-Oncogene Protein - genetics / N-Myc Proto-Oncogene Protein - metabolism / Neoplasm Invasiveness - genetics / Neuroblastoma / Neuroblastoma - genetics / Neuroblastoma - metabolism / Neuroblastoma - mortality / Neuroblastoma - pathology / Oncology / Pathogenesis / Patients / patient‐derived xenografts / Prognosis / RNA-mediated interference / Transferases - genetics / Tumors / Up-Regulation / Xenograft Model Antitumor Assays / Xenografts