Toll-like receptor 9: AEP takes control

ELK1 Enhances Pancreatic Cancer Progression Via LGMN and Correlates with Poor Prognosis

Pancreatic cancer is one of the most lethal cancers and its prognosis is extremely poor. Clarification of molecular mechanisms and identification of prognostic biomarkers are urgently needed. Though we previously found that LGMN was involved in pancreatic carcinoma progression, the upstream regulation of LGMN remains unknown. We used reliable software to search for the potential transcription factors that may be related with LGMN transcription, we found that ELK1 could be a new regulator of LGMN transcription that binded directly to the LGMN promoter. Moreover, knocking down of ELK1 reduced pancreatic cancer cells proliferation, invasion and survival, while LGMN restored the malignancy of pancreatic cancer in vitro and in vivo. Overexpression of ELK1 further increased cancer cells proliferation, invasion and survival. Clinically, ELK1 and LGMN were positively correlated with clinical stage, degree of differentiation and Lymph node infiltration. ELK1 and LGMN were identified as independent prognostic factors for overall survival. The patients with low expression of ELK1/LGMN survived an average of 29.65 months, whereas those with high expression of ELK1/LGMN survived an average of 16.67 months. In conclusive, our results revealed a new mechanism by which ELK1 promoted the progression of pancreatic cancer via LGMN and conferred poor prognosis.

Circular RNA circLGMN facilitates glioblastoma progression by targeting miR-127-3p/LGMN axis

Glioblastoma (GBM) is one of the most devastating cancers and is characterized by rapid cell proliferation and aggressive invasiveness. Legumain (LGMN), a substrate-specific protease, is associated with poor progression of GBM. Circular RNAs (circRNAs) are aberrantly expressed in various cancers and play crucial roles in tumor progression; however, the functional roles of circRNAs originating from LGMN remain largely unknown in GBM. Herein, we found that hsa_circ_0033009 (circLGMN) was the most abundantly expressed circRNA derived from LGMN. CircLGMN was upregulated in high-grade glioma (HGG), and high expression of circLGMN was associated with poor prognosis in patients with glioma. CircLGMN overexpression promoted GBM cell proliferation and enhanced cell invasion. Mechanistically, circLGMN acts as a sponge for miR-127-3p, and prevents miR-127-3p-mediated degradation of LGMN mRNA, ultimately leading to increased LGMN protein expression. Treatment with miR-127-3p mimic suppressed proliferation and reduced invasion of GBM cells overexpressing circLGMN. Moreover, circLGMN overexpression promoted GBM malignancy in vivo, while miR-127-3p overexpression alleviated this effect. Taken together, circLGMN is a novel tumor-promoting circRNA that acts by sponging miR-127-3p, which ultimately leads to LGMN upregulation. Thus, targeting the circLGMN/miR-127-3p/LGMN axis might be a promising strategy for GBM treatment. More importantly, the discovery of the self-regulatory mechanism of LGMN expression by circLGMN, will facilitate further research on LGMN.

Asparaginyl endopeptidase enhances pancreatic ductal adenocarcinoma cell invasion in an exosome-dependent manner and correlates with poor prognosis

Pancreatic cancer is one of the most lethal types of cancer; owing to low early detection rates and high metastasis rates, it is associated with an extremely poor prognosis. Therefore, a better understanding of the molecular mechanisms that underlie its metastasis and the identification of potential prognostic biomarkers are urgently required. Although high expression levels of asparaginyl endopeptidase (AEP) have been detected in various types of solid tumor, the expression and functions of AEP in pancreatic carcinomas have yet to be determined. The present study aimed to examine the putative functions of AEP in pancreatic carcinoma. Immunohistochemical analysis revealed that AEP was highly expressed in pancreatic cancer tissues compared with adjacent normal tissues. Patients with high AEP expression exhibited a significantly shorter overall survival time. Results from multivariate Cox regression analysis revealed that AEP was an independent prognostic factor for overall survival. Gain- and loss-of-function experiments demonstrated that knockdown of AEP expression significantly reduced the invasive ability of pancreatic cancer cells, whereas overexpression of AEP increased the invasive ability. In addition, AEP was detected in exosomes that were derived from cultured pancreatic ductal adenocarcinoma cells (PDACs) and in the serum from patients with PDAC. The Matrigel-Transwell invasion assay revealed that exosomes enriched with AEP were able to enhance the invasive ability of PDAC cells, whereas exosomes lacking AEP decreased the invasive ability. Furthermore, results from the present study suggested that AEP may be crucial for activation of the phosphoinositide 3-kinase/RAC‑α serine/threonine-protein kinase signaling pathway in PDAC cells. The present study data indicated that high AEP expression may be important for pancreatic carcinoma progression in an exosome-dependent manner, and that AEP may be an independent indicator of poor prognosis in patients with PDAC and may be a novel prognostic biomarker or therapeutic target in pancreatic carcinoma.