ARHGAP4 regulates the cell migration and invasion of pancreatic cancer by the HDAC2/β-catenin signaling pathway

Abstract

β-catenin is a subunit of the cadherin protein complex and acts as an intracellular signal transducer in the Wnt signaling pathway that mediates multiple cellular processes, such as cell migration and invasion. HDAC2 (histone deacetylase 2), a deacetylase that maintains histone H3 in a deacetylated state in the promoter region of Wnt-targeted genes where β-catenin is bound, negatively regulating β-catenin activation. However, the regulation of HDAC2/β-catenin pathway remains unclear. Here, we report ARHGAP4 as a new regulator of the β-catenin pathway that regulates cell invasion and migration of pancreatic cancer as well as the downstream effector MMP2 and MMP9 expression in vitro. Mechanistically, ARHGAP4 interacts with and ubiquitinates HDAC2, which in turn inhibits β-catenin activation. Furthermore, treatment of CAY10683, an HDAC2 inhibitor, and XAV939, a Wnt/β-catenin pathway inhibitor, attenuated the effects of ARHGAP4 silencing on pancreatic cancer cells. Overall, our findings establish ARHGAP4 as a novel regulator of HDAC2/β-catenin pathway with a critical role in tumorigenesis.

<p>miR-939-5p Contributes to the Migration and Invasion of Pancreatic Cancer by Targeting ARHGAP4</p>

“…25 In addition to p190 RhoGAP, only ARHGAP4 has been found to correlate with pathological stages, vascular invasion and prognosis of pancreatic cancer patients and regulate Warburg effect as well as cell invasion and migration. 12,13 Our previous study demonstrated decreased ARHGAP4 protein levels in pancreatic cancer tissues based on the immunohistochemical staining on tissue microarrays. Here, the decreased ARHGAP4 mRNA levels in pancreatic cancer tissues were also observed compared with the adjacentnormal tissues.…”

“…Our previous studies have shown that ARHGAP4 could regulate the invasion and migration in pancreatic cancer cells. 12 Therefore, we suggested that miR-939-5p may also contribute to pancreatic cancer progression. We first investigated miR-939-5p expressions by Real-time PCR analysis in pancreatic cancer.…”

“…The cell migration and invasion were measured by Transwell assay as previously described. 12 Real-Time PCR Total RNA was extracted using RNeasy Plus Universal Kits (QIAGEN, USA). cDNA was synthesized from 1 μg of total RNA via thermal cycler system (Bio-Rad, USA).…”

“…Our previous studies have shown decreased ARHGAP4 protein expression in pancreatic cancer tissues compared with the non-tumor tissues by immunohistochemistry. 12,13 Here, the ARHGAP4 mRNA expression was also measured by Real-time PCR analysis in pancreatic cancer tissues. ARHGAP4 mRNA levels in pancreatic cancer tissues were markedly decreased compared with the adjacent-normal tissues ( Figure 1A).…”

“…9 Besides, evidences have been reported that ARHGAP4 inhibits cell motility and axon outgrowth, 10 associates with nephrogenic diabetes insipidus and intellectual disability, 11 correlates with pathological stages, vascular invasion and prognosis of pancreatic cancer patients, and regulates glycolysis, invasion and migration in pancreatic cancer. 12,13 Nevertheless, the regulation of ARHGAP4 in pancreatic cancer is still undiscovered microRNAs (miRNA) are small endogenous non-coding RNA molecules with a length of about 18-25 nucleotides that repress protein translation through binding to the 3ʹ-untranlated region (UTR) of their target mRNA and are significantly involved in various cancers, including pancreatic cancer. [14][15][16] High expression of miR-196a, miR-27a, miR-221, miR-143, miR-135b, miR-199b-5p and miR-21, but low expression of miR-744, miR-455-3p and miR-655, in pancreatic cancer samples were found compared with normal samples and associated with poor prognosis.…”