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Neuro Oncol. 2015 Feb;17(2):243-53. doi: 10.1093/neuonc/nou217. Epub 2014 Aug 30.

Targeting the SMO oncogene by miR-326 inhibits glioma biological behaviors and stemness.

Author information

1
Department of Neurosurgery, Second Affiliated Hospital of Harbin Medical University, Harbin, China (W.D., X.L., Z.D., X.L., L.C., J.C., Y.C., D.Y., Y.S., Y.L., C.J.); Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China (L.C.).

Abstract

BACKGROUND:

Few studies have associated microRNAs (miRNAs) with the hedgehog (Hh) pathway. Here, we investigated whether targeting smoothened (SMO) with miR-326 would affect glioma biological behavior and stemness.

METHODS:

To investigate the expression of SMO and miR-326 in glioma specimens and cell lines, we utilized quantitative real-time (qRT)-PCR, Western blot, immunohistochemistry, and fluorescence in situ hybridization. The luciferase reporter assay was used to verify the relationship between SMO and miR-326. We performed cell counting kit-8, transwell, and flow cytometric assays using annexin-V labeling to detect changes after transfection with siRNA against SMO or miR-326. qRT-PCR assays, neurosphere formation, and immunofluorescence were utilized to detect the modification of self-renewal and stemness in U251 tumor stem cells. A U251-implanted intracranial model was used to study the effect of miR-326 on tumor volume and SMO suppression efficacy.

RESULTS:

SMO was upregulated in gliomas and was associated with tumor grade and survival period. SMO inhibition suppressed the biological behaviors of glioma cells. SMO expression was inversely correlated with miR-326 and was identified as a novel direct target of miR-326. miR-326 overexpression not only repressed SMO and downstream genes but also decreased the activity of the Hh pathway. Moreover, miR-326 overexpression decreased self-renewal and stemness and partially prompted differentiation in U251 tumor stem cells. In turn, the inhibition of Hh partially elevated miR-326 expression. Intracranial tumorigenicity induced by the transfection of miR-326 was reduced and was partially mediated by the decreased SMO expression.

CONCLUSIONS:

This work suggests a possible molecular mechanism of the miR- 326/SMO axis, which can be a potential alternative therapeutic pathway for gliomas.

KEYWORDS:

SMO; glioma; hedgehog; miRNA; stemness

PMID:
25173582
PMCID:
PMC4288524
DOI:
10.1093/neuonc/nou217
[Indexed for MEDLINE]
Free PMC Article

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