GLI2 promotes cell proliferation and migration through transcriptional activation of ARHGEF16 in human glioma cells

Abstract

BackgroundThe Hedgehog (Hh) signaling pathway plays critical roles in modulating embryogenesis and maintaining tissue homeostasis, with glioma-associated oncogene (GLI) transcription factors being the main mediators. Aberrant activation of this pathway is associated with various human malignancies including glioblastoma, although the mechanistic details are not well understood.MethodsWe performed a microarray analysis of genes that are differentially expressed in glioblastoma U87 cells overexpressing GLI2A, the active form of GLI2, relative to the control cells. Chromatin immunoprecipitation and dual-luciferase assays were used to determine whether Rho guanine nucleotide exchange factor 16 (ARHGEF16) is a downstream target of GLI2. Then, transwell migration, EdU and soft-agar colony formation assays were employed to test effects of ARHGEF16 on glioma cancer cell migration and proliferation, and the effects of GLI2/ARHGEF16 signaling on tumor growth were examined in vivo. Finally, we performed yeast two-hybrid assay, Co-IP and GST-pull down to identify factors that mediate effects of ARHGEF16.ResultsWe found that ARHGEF16 mRNA level was upregulated in U87 cells overexpressing GLI2A relative to control cells. GLI2 binds to the ARHGEF16 promoter and activates gene transcription. Glioma cells U87 and U118 overexpressing ARHGEF16 showed enhanced migration and proliferation relative to the control cells, while knockdown of ARHGEF16 in H4 cells led to decreased cell proliferation compared to the control H4 cells. In contrast to the promoting effect of GLI2A overexpression on glioma xenograft growth, both GLI2 inhibition and ARHGEF16 knockdown retarded tumor growth. Cytoskeleton-associated protein 5 (CKAP5) was identified as an interaction protein of ARHGEF16, which is important for the stimulatory effects of ARHGEF16 on glioma cell migration and proliferation.ConclusionsThese results suggest that therapeutic strategies targeting the GLI2/ARHGEF16/CKAP5 signaling axis could inhibit glioma progression and recurrence.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0917-x) contains supplementary material, which is available to authorized users.

Hedgehog signaling promotes multidrug resistance by regulation of ABC transporters in oral squamous cell carcinoma

“…24 In human glioma cells, it also has been suggested that GLI2 promotes cell proliferation and migration through transcriptional activation of ARHGEF16. 25 These results are consistent with our data, compared to CAL27 cells, CAL27-MDR showed lower expression of GLI2 with decreased proliferation ( Figure 2C and Figure S3). It is reasonable that comprehensive pathways might regulate the activation of GLI2 in OSCC-MDR, and investigations should be conducted to gain further insight.…”

TGLI1 transcription factor mediates breast cancer brain metastasis via activating metastasis-initiating cancer stem cells and astrocytes in the tumor microenvironment

“…FGF19, the human ortholog of FGF15, is essential for embryonic brain development 41 and overexpression of FGF19 is implicated in breast cancer progression and metastasis 42 . ARHGEF16 was recently shown to promote glioma cell migration and proliferation 22 . Upregulation of these GLI2 target genes by TGLI1 further contributes to the aggressiveness of TGLI1.…”

“…6D). We next examined whether TGLI1 regulates expression of GLI2 target genes [22][23][24] and found TGLI1 to upregulate GLI2 target genes to a higher extent than GLI1 ( Supplementary Fig. 3E).…”

Transcription activation of circ-STAT3 induced by Gli2 promotes the progression of hepatoblastoma via acting as a sponge for miR-29a/b/c-3p to upregulate STAT3/Gli2

“…The more significant suppressive effects of miR-29a/b/c-3p on STAT3 than on Gli2 as well as the complete rescue effects of Gli2 on circ-STAT3-mediated cell functions aroused our interest. It has been verified that circRNAs and their host genes could be regulated by the common transcription factor [23], and Gli2 was previously reported as the transcription factor to activate upregulation of its downstream genes [24]. We wondered whether Gli2 transcriptionally activated STAT3 and further up-regulated circ-STAT3.…”