Identifying hedgehog signaling specific microRNAs in glioblastomas

Abstract

Aberrant activation of hedgehog (Hh) signaling pathway plays an important role in the development and proliferation of glioblastoma (GBM) cells. However, its mechanism remains unknown. MicroRNAs (miRNAs) are short non-coding RNA molecules which are involved in the post-transcriptional regulation of genes, and enrolled in signaling transduction network in tumors. This study was designed to investigate the role of miRNAs targeting the Hh signaling pathway in GBMs. According to the expression level of Gli1 mRNA measured by real time PCR, GBM samples were assigned to Gli1 high or low expression group. MiRNA microarray was applied to screen the dysregulated miRNA. As a result, 17 miRNAs were differentially expressed between Gli1 high expression and low expression groups (p < 0.005). Thirteen miRNAs including miR-125b-1 were downregulated, while only 4 miRNAs including miR-144 were upregulated in Gli1 high expression group. In summary, our study presents a subset of miRNAs which target the Hh signaling pathway in GBMs, and throws some light on the aberrant activation mechanism.

Keywords: Glioblastoma; Hedgehog; MicroRNA; Signaling pathway..

Figure 1

Relative Gli1 expression in glioblastoma tissues( each plot represent one tissue ).

Figure 2

Heat map clustering of differential expression of miRNAs in Gli1 high versus Gli1 low GBMs. (Red indicates high relative expression, and green indicates low relative expression).

Figure 3

Differential expression of miRNAs in Gli1 high versus Gli1 low GBMs which passed Volcano Plot. (Fold change 1.5, p<0.005) (the Red spots represents the target miRNAs).

Figure 4

Ectopic overexpression of miR-125b-1 and miR-144 in A172 glioma cells. A. Relative viable cell numbers in A172 cells after transfection with miR-125b-1 or miR-144 or miRNA mimic negative control(ctr). B. Western blot analysis of Gli1 (upper panel) or ß-actin (bottom panel) protein levels in A172 cells 48 h after transfection with miR-125b-1 or miR-144 or compared with scrambled control (ctr).