hsa_circRNA_001587 upregulates SLC4A4 expression to inhibit migration, invasion, and angiogenesis of pancreatic cancer cells via binding to microRNA-223.

Pancreatic cancer (PC) is a malignant tumor that is difficult to diagnose and treat. Circular RNAs (circRNAs) are biomarkers that may be used to diagnose certain cancers or act as targets for cancer treatment. We aimed to explore the functions of human circular RNA 001587 (hsa_circRNA_001587) on the progression of PC and the underlying mechanism. The expression pattern of hsa_circRNA_001587 and microRNA-223 (miR-223) in PC tissues and cells was determined by RT-qPCR. Dual-luciferase reporter gene assay, RNA-pulldown, Argonaute 2 (AGO2) immunoprecipitation assay, and Northern blot analysis were applied to verify the binding relationships among hsa_circRNA_001587, miR-223 and solute carrier family 4 member 4 (SLC4A4). Further analysis of their roles was performed in PC cell line PANC-1. Moreover, we either downregulated or upregulated the expression of hsa_circRNA_001587, miR-223, and SLC4A4 by transfection in vitro. A mouse xenograft model of PC cells was established to evaluate tumor growth in vivo. hsa_circRNA_001587 was poorly expressed, but miR-223 was highly expressed in PC tissues and cell lines. Upregulation of hsa_circRNA_001587 downregulated the expression of matrix metalloproteinase-2 and-9, minichromosome maintenance 2, and vascular endothelial growth factor, and decreased the proliferation, migration, invasion, angiogenic and tumorigenic abilities of PC cells. MiR-223, which can bind with hsa_circRNA_001587, reversed the effects of hsa_circRNA_001587 on PC cells. In addition, SLC4A4 was identified as a target of miR-223, and its knockdown could counteract the regulatory effects of overexpressed hsa_circRNA_001587 or inhibited miR-223 expression on PC cells. Therefore, hsa_circRNA_001587 inhibits PC cell migration, invasion, angiogenesis and tumorigenesis by impairing miR-223-mediated SLC4A4 inhibition.NEW & NOTEWORTHY Human circular (hsa_circ)RNA_001587 and solute carrier family 4 member 4 (SLC4A4) are poorly expressed but microRNA (miR)R-223 is overexpressed in pancreatic cancer (PC) cells. hsa_circRNA_001587 binds to miR-223. Overexpression of hsa_circRNA_001587 inhibits PC progression. Overexpression of miR-223 downregulates the expression of SLC4A4 and promotes PC cell growth. hsa_circRNA_001587 may be a potential target for PC treatment.

microRNA-95 knockdown inhibits epithelial-mesenchymal transition and cancer stem cell phenotype in gastric cancer cells through MAPK pathway by upregulating DUSP5.

This study investigated the role of microRNA-95 (miR-95) in gastric cancer (GC) and to elucidate the underlying mechanism. Initially, bioinformatic prediction was used to predict the differentially expressed genes and related miRNAs in GC. miR-95 and DUSP5 expression was altered in GC cell line (MGC803) to evaluate their respective effects on the epithelial-mesenchymal transition (EMT) process, cellular processes (cell proliferation, migration, invasion, cell cycle, and apoptosis), cancer stem cell (CSC) phenotype, as well as tumor growth ability. It was further predicted in bioinformatic prediction and verified in GC tissue and cell line experiments that miR-95 was highly expressed in GC. miR-95 negatively regulated DUSP5, which resulted in the MAPK pathway activation. Inhibited miR-95 or overexpressed DUSP5 was observed to inhibit the levels of CSC markers (CD133, CD44, ALDH1, and Lgr5), highlighting the inhibitory role in the CSC phenotype. More important, evidence was obtained demonstrating that miR-95 knockdown or DUSP5 upregulation exerted an inhibitory effect on the EMT process, cellular processes, and tumor growth. Together these results, miR-95 knockdown inhibited GC development via DUSP5-dependent MAPK pathway.

Long Non-Coding RNA (lncRNA) X-Inactive Specific Transcript (XIST) Plays a Critical Role in Predicting Clinical Prognosis and Progression of Colorectal Cancer.

BACKGROUND Long non-coding RNAs (lncRNAs) participate in all cancer biology processes of cells. Although functions and associated mechanisms of lncRNAs have been proven in colorectal cancer (CRC), the roles of lncRNA X-inactive specific transcript (XIST) have not been clearly investigated in CRC. MATERIAL AND METHODS Expression of XIST was detected by quantitative real-time PCR (qRT-PCR) assay in CRC cell lines and 196 clinical samples. Correlations between XIST expression and CRC clinicopathological features were analyzed. Log-rank test and Kaplan-Meier test were performed to assess and compare the prognoses of patients with higher and lower expression of XIST. The multivariate Cox regression and univariate Cox regression were conducted to evaluate the risk factors for prognosis of CRC. RESULTS lncRNA XIST was upregulated in CRC cells lines and tissues (p<0.05). Statistical analysis found high XIST expression was correlated with larger tumor size, N1, M1, and topography lymph node metastasis (TNM) III+IV stage of CRC. Moreover, higher expression of XIST could predict poor progression-free survival (PFS) and poor overall survival (OS) of CRC patients. The M1 stage and high expression of XIST were proven to be independent risk factors for poor prognosis (p<0.05). CONCLUSIONS XIST is upregulated in CRC and is significantly correlated with CRC clinical progression. lncRNA XIST overexpression predict poor PFS and poor OS for CRC patients. lncRNA XIST can be an independent risk factor for CRC prognosis, and could be a potential therapeutic target and prognostic biomarker for CRC patients.

Down-regulation of long non-coding RNA HOTAIR inhibits invasion and migration of oesophageal cancer cells via up-regulation of microRNA-204.

Oesophageal cancer is a progressive tumour with high mortality. However, therapies aimed at treating oesophageal cancer remain relatively limited. Accumulating studies have highlighted long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR), microRNA-204 (miR-204) and homeobox C8 (HOXC8) in the progression of oesophageal cancer. Herein, we tried to demonstrate the function of HOTAIR, miR-204 and HOXC8 in oesophageal cancer and their relationship. Differentially expressed genes involved in oesophageal cancer were identified. The endogenous expression of HOTAIR and miR-204 in oesophageal cancer cell lines was altered to elucidate their effects and to identify the interaction among HOTAIR, miR-204 and HOXC8. We also explored the underlying regulatory mechanisms of HOTAIR and miR-204 with siRNA against HOTAIR, miR-204 mimic or miR-204 inhibitor. Cell proliferation, migration, invasion and apoptosis were subsequently detected. Xenograft in nude mice was induced to evaluate tumourigenicity. miR-204 was down-regulated, while HOTAIR and HOXC8 were up-regulated in the oesophageal cancer tissues. HOTAIR could competitively bind to miR-204 and miR-204 could further target HOXC8. The oesophageal cancer cells treated with si-HOTAIR or miR-204 mimic exhibited decreased expression levels of HOXC8, Vimentin and MMP-9, but increased E-cadherin level. Silenced HOTAIR or elevated miR-204 inhibited proliferation, migration and invasion, along with stimulated apoptosis of oesophageal cancer cells. In summary, our results show that lncRNA HOTAIR could specifically bind to miR-204 as a competing endogenous RNA and regulate miR-204 and HOXC8. Hence, down-regulation of HOTAIR could inhibit progression of oesophageal cancer, indicating a novel target for oesophageal cancer treatment.

Long noncoding RNA microvascular invasion in hepatocellular carcinoma is an indicator of poor prognosis and a potential therapeutic target in gastric cancer.

BACKGROUND: Long noncoding RNAs (lncRNAs) have been shown to have a fundamental role in cancer initiation and development. LncRNA microvascular invasion in hepatocellular carcinoma (MVIH) has been identified as a potential prognostic marker in several cancers; however, its role in gastric cancer (GC) has not been elucidated. MATERIALS AND METHODS: A total of 152 tissue samples from patients underwent GC surgical resection in Linyi People's Hospital between 2007 and 2010 were collected. Quantitative real-time polymerase chain reaction was conducted to examine the expression level of lncRNA MVIH. The selection of clinically important cut-off scores for MVIH expression was based on receiver operating characteristic curve analysis. Then, the association between MVIH and GC clinicopathological parameters was analyzed. Moreover, univariate and multivariate Cox regression analysis were performed to reveal the relationship between MVIH and GC prognosis. RESULTS: GC tissues exhibited a higher lncRNA MVIH expression level than paired nontumoros tissues. High MVIH level was revealed to be associated with the T stage, tumor-node-metastasis (TNM) stage and lymphatic metastasis of GC. Specially, patients with high MVIH expression level showed significantly shorter overall survival rate and progression-free survival rate. Moreover, invasion depth, distant metastasis, TNM stage, and MVIH expression were identified as risk factors of GC poor prognosis on univariate Cox regression analyses. By further analyzing these factors with multivariate logistic regression, high MVIH, and distant metastasis were discovered to be independent risk factors of GC prognosis. CONCLUSIONS: High MVIH is an independent risk factor of GC prognosis. LncRNA MVIH may serve as a potential therapeutic target and a prognostic marker of GC patients.

Clinical application of clustered-AChR for the detection of SNMG.

Myasthenia gravis (MG) is an autoantibody-mediated disease of the neuromuscular junction (NMJ). However, accumulating evidence has indicated that MG patients whose serum anti-acetylcholine receptor (AChR) antibodies are not detectable (serumnegative MG; SNMG) in routine assays share similar clinical features with anti-AChR antibody-positive MG patients. We hypothesized that SNMG patients would have low-affinity antibodies to AChRs that would not be detectable using traditional methods but that might be detected by binding to AChR on the cell membrane, particularly if they were clustered at the high density observed at the NMJ. We expressed AChR subunits with the clustering protein rapsyn (an AChR-associated protein at the synapse) in human embryonic kidney (HEK) cells, and we tested the binding of the antibodies using immunofluorescence. With this approach, AChR antibodies to rapsyn-clustered AChR could be detected in the sera from 45.83% (11/24) of SNMG patients, as confirmed with fluorescence-activated cell sorting (FACS). This was the first application in China of cell-based AChR antibody detection. More importantly, this sensitive (and specific) approach could significantly increase the diagnosis rate of SNMG.