MYCN-regulated microRNAs repress estrogen receptor-alpha (ESR1) expression and neuronal differentiation in human neuroblastoma.
MYCN, a proto-oncogene normally expressed in the migrating neural crest, is in its amplified state a key factor in the genesis of human neuroblastoma (NB). However, the mechanisms underlying MYCN-mediated NB progression are poorly understood. Here, we present a MYCN-induced miRNA signature in human NB involving the activation and transrepression of several miRNA genes from paralogous clusters. Several family members derived from the miR-17 approximately 92 cluster, including miR-18a and miR-19a, were among the up-regulated miRNAs. Expression analysis of these miRNAs in NB tumors confirmed increased levels in MYCN-amplified samples. Specifically, we show that miR-18a and miR-19a target and repress the expression of estrogen receptor-alpha (ESR1), a ligand-inducible transcription factor implicated in neuronal differentiation. Immunohistochemical staining demonstrated ESR1 expression in human fetal sympathetic ganglia, suggesting a role for ESR1 during sympathetic nervous system development. Concordantly, lentiviral restoration of ESR1 in NB cells resulted in growth arrest and neuronal differentiation. Moreover, lentiviral-mediated inhibition of miR-18a in NB cells led to severe growth retardation, outgrowth of varicosity-containing neurites, and induction of neuronal sympathetic differentiation markers. Bioinformatic analyses of microarray data from NB tumors revealed that high ESR1 expression correlates with increased event-free survival in NB patients and favorable disease outcome. Thus, MYCN amplification may disrupt estrogen signaling sensitivity in primitive sympathetic cells through deregulation of ESR1, thereby preventing the normal induction of neuroblast differentiation. Collectively, our findings demonstrate the molecular consequences of abnormal miRNA transcription in a MYCN-driven tumor and offer unique insights into the pathology underlying MYCN-amplified NB.
Lovén
Jakob
J
Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Zinin
Nikolay
N
Wahlström
Therese
T
Müller
Inga
I
Brodin
Petter
P
Fredlund
Erik
E
Ribacke
Ulf
U
Pivarcsi
Andor
A
Påhlman
Sven
S
Henriksson
Marie
M
D020413:3' Untranslated Regions; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D000071447:N-Myc Proto-Oncogene Protein; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D000090063:Proto-Oncogene Mas; D015398:Signal Transduction; D014158:Transcription, Genetic
D020413:3' Untranslated Regions; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; C000715470:MAS1 protein, human; C459801:MYCN protein, human; D035683:MicroRNAs; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D000090063:Proto-Oncogene Mas