MicroRNA-30e* promotes human glioma cell invasiveness in an orthotopic xenotransplantation model by disrupting the NF-κB/IκBα negative feedback loop
Lili Jiang, … , Jun Li, Mengfeng Li
Lili Jiang, … , Jun Li, Mengfeng Li
Published December 12, 2011
Citation Information: J Clin Invest. ;122(1):33-47. https://doi.org/10.1172/JCI58849.
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MicroRNA-30e* promotes human glioma cell invasiveness in an orthotopic xenotransplantation model by disrupting the NF-κB/IκBα negative feedback loop

Abstract

Constitutive activation of NF-κB is a frequent event in human cancers, playing important roles in cancer development and progression. In nontransformed cells, NF-κB activation is tightly controlled by IκBs. IκBs bind NF-κB in the cytoplasm, preventing it from translocating to the nucleus to modulate gene expression. Stimuli that activate NF-κB signaling trigger IκB degradation, enabling nuclear translocation of NF-κB. Among the genes regulated by NF-κB are those encoding the IκBs, providing a negative feedback loop that limits NF-κB activity. How transformed cells override this NF-κB/IκB negative feedback loop remains unclear. Here, we report in human glioma cell lines that microRNA-30e* (miR-30e*) directly targets the IκBα 3ι-UTR and suppresses IκBα expression. Overexpression of miR-30e* in human glioma cell lines led to hyperactivation of NF-κB and enhanced expression of NF-κB–regulated genes, which promoted glioma cell invasiveness in in vitro assays and in an orthotopic xenotransplantation model. These effects of miR-30e* were shown to be clinically relevant, as miR-30e* was found to be upregulated in primary human glioma cells and correlated with malignant progression and poor survival. Hence, miR-30e* provides an epigenetic mechanism that disrupts the NF-κB/IκBα loop and may represent a new therapeutic target and prognostic marker.

Authors

Lili Jiang, Chuyong Lin, Libing Song, Jueheng Wu, Baixue Chen, Zhe Ying, Lishan Fang, Xiao Yan, Mian He, Jun Li, Mengfeng Li

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Figure 1

Upregulation of miR-30e* enhances invasiveness of glioma cells.

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Upregulation of miR-30e* enhances invasiveness of glioma cells. (A) ...
(A) miRNA array analysis showed that miRNAs were differentially expressed in GFAP+ cells isolated from clinical glioma and adjacent brain tissues. The pseudocolor represents the intensity scale of tumor versus adjacent brain tissue. (B) Correlation between miR-30e* expression assessed by real-time PCR and WHO grading of glioma and normal brain tissues (N). Transcript levels were normalized by U6 expression. The bounds of boxes represent the lower and upper quartiles; lines within boxes and whiskers denote median and extremum, respectively. (C) Correlation between miR-30e* levels and survival by Kaplan-Meier analysis of patients with high (greater than the median; n = 64) or low miR-30e* (less than the median; n = 63) expression. (D) Northern blot analysis of miR-30e* expression in glioma cells transfected with negative control (NC) and hsa-miR-30e* mimic oligonucleotides, as well as 4 clinical WHO grade IV glioma tissues. The expression levels of miR-30e* in the transfected gliomas cells were within the range of the endogenously expressed miR-30e* levels in human gliomas (see Supplemental Methods). Numbers below the panels are quantifications of the signals obtained, determined by comparing the miR-30e*/U6 ratio in U87MG-NC cells. The miR-30e*/U6 ratio in U87MG-NC cells was set at 1.0. (E) Representative micrographs of indicated cells cultured in a 3D spheroid invasion assay. (F) Representative images and quantification of indicated invaded cells analyzed in a TMPA with Matrigel. Experiments in B–F were repeated at least 3 times, with similar results. **P < 0.01. Original magnification, ×400 (E); ×200 (F).