miR‐130b directly targets ARHGAP1 to drive activation of a metastatic CDC42‐PAK1‐AP1 positive feedback loop in Ewing sarcoma

Abstract

Ewing Sarcoma (ES) is a highly aggressive bone tumor with peak incidence in the adolescent population. It has a high propensity to metastasize, which is associated with dismal survival rates of approximately 25%. To further understand mechanisms of metastasis we investigated microRNA regulatory networks in ES. Our studies focused on miR-130b due to our analysis that enhanced expression of this microRNA has clinical relevance in multiple sarcomas, including ES. Our studies provide insights into a novel positive feedback network involving the direct regulation of miR-130b and activation of downstream signaling events contributing towards sarcoma metastasis. Specifically, we demonstrated miR-130b induces proliferation, invasion, and migration in vitro and increased metastatic potential in vivo. Using microarray analysis of ES cells with differential miR-130b expression we identified alterations in downstream signaling cascades including activation of the CDC42 pathway. We identified Arhgap1, which is a negative regulator of CDC42, as a novel, direct target of miR-130b. In turn, downstream activation of PAK1 activated the JNK and AP-1 cascades and downstream transcriptional targets including IL-8, MMP1 and CCND1. Furthermore, chromatin immunoprecipitation of endogenous AP-1 in ES cells demonstrated direct binding to an upstream consensus binding site within the miR-130b promoter. Finally, small molecule inhibition of PAK1 blocked miR-130b activation of JNK and downstream AP-1 target genes, including primary miR-130b transcripts, and mir-130b oncogenic properties, thus identifying PAK1 as a novel therapeutic target for ES. Taken together, our findings identify and characterize a novel, targetable miR-130b regulatory network that promotes ES metastasis.

Defining a Characteristic Gene Expression Set Responsible for Cancer Stem Cell-Like Features in a Sub-Population of Ewing Sarcoma Cells CADO-ES1

“…The link between MSCs as cells of origin and Ewing sarcoma was exemplified by a publication by Tirode et al [14]. The recent publication of Satterfield et al [58] is pointing towards a miR-130B interaction with the AP-1 complex forming an oncogenic feed-forward loop. An older study from Whitehurst et al [59] discuesses an APC/c-associated EWSR1 fusion protein co-expression with RASSF1A, but the corresponding gene was not observed in our, specifically to stemness features adjusted, differential analysis.…”

Moderate Fluid Shear Stress Could Regulate the Cytoskeleton of Nucleus Pulposus and Surrounding Inflammatory Mediators by Activating the FAK-MEK5-ERK5-cFos-AP1 Signaling Pathway

“…Many genes have AP-1 binding sites [ 11 ]. AP-1 regulates a series of pathophysiological processes, such as cell growth and differentiation, by binding to promoters or enhancers in genes [ 12 ]. AP-1 exists in many kinds of cells, and can be induced by stress, hormones, growth factors, cytokines, nerve media, heat shock, electroshock, ultraviolet ray, and oxygen stress [ 13 ].…”

MicroRNA‑195 suppresses cell proliferation, migration and invasion in epithelial ovarian carcinoma via inhibition of the CDC42/CCND1 pathway

“…The cdc42/ccNd1 signaling pathway has been reported to promote cell migration and proliferation in endothelial cells. In addition, activation of the cdc42/ccNd1 pathway could induce cell proliferation, migration and invasion to increase Ewing sarcoma metastasis (31). Overexpression of cdc42 and ccNd1 has also been shown to cause increased cell migration, changes in cell morphology, G 1 /S phase cell cycle progression and decreased apoptosis in colorectal cancer cells (30).…”