MicroRNA-25 promotes gastric cancer migration, invasion and proliferation by directly targeting transducer of ERBB2, 1 and correlates with poor survival

Targeting non-coding RNAs as a promising biomarker in peritoneal metastasis: Background, mechanism, and therapeutic approach

Peritoneal metastasis (PM) pathophysiology is complex and not fully understood. PM, originating from gastrointestinal (GI) cancer, is a condition that significantly worsens patient prognosis due to its complex nature and limited treatment options. The non-coding RNAs (ncRNAs) have been shown to play pivotal roles in cancer biology, influencing tumorigenesis, progression, metastasis, and therapeutic resistance. Increasing evidence has demonstrated the regulatory functions of different classes of ncRNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in PM. Identifying biomarkers for early detection of PM is a crucial step towards improving patient outcomes, and how ncRNA profiles correlate with survival rates, response to therapy, and recurrence risks have raised much attention in recent years. Additionally, exploring innovative therapeutic approaches utilizing ncRNAs, such as targeted therapy and gene silencing, may offer new horizons in treating this dire condition. Recent advances in systemic treatments and the development of novel loco-regional therapies have opened doors to multimodal treatment approaches. Radical surgeries combined with hyperthermic intraperitoneal chemotherapy (HIPEC) have shown promising results, leading to extended patient survival. Current research is focused on the molecular characterization of PM, which is crucial for early detection and developing future therapeutic strategies. By summarizing the latest findings, this study underscores the transformative potential of ncRNAs in enhancing the diagnosis, prognosis, and treatment of PM in GI cancer, paving the way for more personalized and effective clinical strategies.

Potential Diagnostic Utility of microRNAs in Gastrointestinal Cancers

Early detection of gastrointestinal cancers is beneficial for patient survival and prognosis. MiRNAs have been shown to be potential cancer biomarkers that can be used to diagnose cancers. MiRNAs are single-stranded, small non-coding RNAs that are involved in the post-transcriptional regulation of the expression of different oncogenes. Cancer tissues contain miRNAs that play a special role in the etiology of cancer development or limiting cancer suppression. Dysregulation of miRNAs occurs in a variety of malignancies, including gastrointestinal cancers. MiRNAs are stable and protected against degradation by RNase, which enables their detection in tissues and biological fluids. The results of many studies suggest that miRNAs have a relatively higher diagnostic efficiency in distinguishing cancer patients from healthy people. The researchers have identified many miRNA signature in the blood for the detection of gastrointestinal cancers. This review focuses on the role and potential utility of miRNAs in the early detection, prognosis and evaluation of the treatment effectiveness of gastrointestinal cancers.

Inhibition of HDAC3 and ATXN3 by miR-25 prevents neuronal loss and ameliorates neurological recovery in cerebral stroke experimental rats

HDAC3 plays important role in regulating memory and plasticity of neurons. We studied the role of miR-25 against HDAC3-induced neuronal injury in acute ischemic stroke. Subjects reported for acute stroke were included in the study. The rat model of middle cerebral artery occlusion was developed and received miR-25 agomir and antagomir treatments via intra-cerebroventricular injection. The brain tissues were processed and neuronal cells were isolated and submitted to oxygen glucose derivation-mediated injury. mRNA levels were studied by RT-PCR and protein levels by ELISA method. TUNEL and nuclear protein staining was done to find the ischemic area. Behavioral studies were carried out by Morris water maze test and beam balance test. Results suggested a significant increase in plasma miR-25 levels observed in acute ischemic stroke subjects. The levels of miR-25 were increased in the tissues of infarcted area of brain tissues of rats. However, the expression of miR-25 decreased in neuronal cells but increased in supernatant post-oxygen glucose deprivation. The treatment of miR-25 agomir decreased the infarct volume and apoptosis of neurons in MCAO rats, and it also improved the plasticity of neurons and axons, down-regulated ATXN3 and HDAC3 levels, and improved acetyl-H3K9 expression. In vitro outcomes suggested that miR-25 inhibited HDAC3 neurons and modulated the oxygen glucose deprivation injury in neurons. The treatment of RGFP966 increased the acetyl-H3K9 levels and prevented the miR-25 antagomir-induced injury. The study suggested miR-25 as an important predicting biomarker in acute ischemia injury. KEY POINTS: • HDAC3 is key regulator for neuronal health. • miR-25 was overexpressed in acute ischemic stroke condition. • miR-25 inhibits loss of neurons and provides neuronal recovery in animal model of stroke via inhibiting HDAC3 and ATXN3.

miR-25 Regulates Gastric Cancer Cell Growth and Apoptosis by Targeting EGR2

Gastric cancer is one of the most common malignancies harmful to human health. The search for effective drugs or gene therapy has aroused the attention of scientists. So far, microRNAs, as small non-coding RNAs, have the potential to be therapeutic targets for cancer. Herein, we found a highly expressed miR-25 in gastric cancer cell. However, the function of miR-25 for gastric cancer cell growth and apoptosis was unknown. Functionally, we used RT-qPCR, western blot, CCK-8, and flow cytometry to detect gastric cancer cell growth and apoptosis. The results indicated that miR-25 promoted gastric cancer cell growth and inhibited their apoptosis. Mechanistically, we found that a gene EGR2 was a potential target gene of miR-25. Further dual-luciferase results supported this prediction. Moreover, knockdown of EGR2 promoted gastric cancer cell growth and inhibited their apoptosis by flow cytometry detection. Altogether, these findings revealed miR-25 as a regulator of gastric cancer cell growth and apoptosis through targeting EGR2.

Effect of miR-25 on Proliferation of Nasopharyngeal Carcinoma Cells through Wnt/β-Catenin Signaling Pathway

OBJECTIVE

To investigate the biological role and potential mechanism of miR-25 in nasopharyngeal carcinoma.

METHODS

The expression of miR-25 in nasopharyngeal carcinoma cell lines was detected by qRT-PCR. The effect of inhibition of miR-25 expression on the proliferative activity of nasopharyngeal carcinoma cell line HONE-1 was examined by CCK-8 method. Flow cytometry was used to detect the effect of miR-25 expression inhibition on the apoptosis rate of nasopharyngeal carcinoma cell line HONE-1. The miRNA target gene prediction site TargetScan predicts the target protein action site of miR-124 and verifies whether miR-25 interacts with the target by luciferase activity assay, qPCR, and Western experiments. The miR-25 inhibitor and target egg gene expression plasmids were cotransfected into HONE-1 cells for rescue experiments to investigate whether miR-25 inhibits proliferation of nasopharyngeal carcinoma cells by target genes. At the same time, qRT-PCR was used to detect the mRNA expression levels of Wnt/β-catenin pathway key proteins TCF4, c-Myc, and Cyclin D1 in different transfected cells.

RESULTS

miR-25 expression was upregulated in nasopharyngeal carcinoma cell lines. Functional studies showed that inhibition of miR-25 expression significantly inhibited the proliferation of nasopharyngeal carcinoma cell line HONE-1 (p < 0.05). Inhibition of miR-25 expression by flow cytometry significantly promoted apoptosis (p < 0.05). Detection of dual luciferase activity indicated that DKK3 is a direct target site for miR-25. Western blots showed that inhibition of miR-25 significantly upregulated DKK3 mRNA and protein levels. Supplementation with DKK3 significantly attenuated the inhibitory effect of miR-25 on the proliferation of nasopharyngeal carcinoma cell line HONE-1 (p < 0.05). qRT-PCR found that mRNA levels of TCF4, c-Myc, and Cyclin D1 were significantly upregulated in miR-25-transfected cells compared to control transfection. QRT PCR showed that the mRNA and protein levels of Tcf4, c-myc, and Cyclin D1 were significantly upregulated in miR-25 overexpression-transfected cells.

CONCLUSION

Inhibition of miR-25 expression promotes DKK3 gene expression, and inactivation of Wnt/β-catenin signaling pathway inhibits proliferation and promotes apoptosis of nasopharyngeal carcinoma cells.

Non-coding driver mutations in human cancer

Tumour formation involves random mutagenic events and positive evolutionary selection acting on a subset of such events, referred to as driver mutations. A decade of careful surveying of tumour DNA using exome-based analyses has revealed a multitude of protein-coding somatic driver mutations, some of which are clinically actionable. Today, a transition towards whole-genome analysis is well under way, technically enabling the discovery of potential driver mutations occurring outside protein-coding sequences. Mutations are abundant in this vast non-coding space, which is more than 50 times larger than the coding exome, but reliable identification of selection signals in non-coding DNA remains a challenge. In this Review, we discuss recent findings in the field, where the emerging landscape is one in which non-coding driver mutations appear to be relatively infrequent. Nevertheless, we highlight several notable discoveries. We consider possible reasons for the relative absence of non-coding driver events, as well as the difficulties associated with detecting signals of positive selection in non-coding DNA.

miR-96-5p enhances cell proliferation and invasion via targeted regulation of ZDHHC5 in gastric cancer

Objective: To explore the biological function and mechanism of miR-96-5p in gastric cancer.

Methods: The expression of differently expressed microRNAs (DEMs) related to gastric adenocarcinoma (GAC) prognosis was identified in GAC tumor samples and adjacent normal samples by qRT-PCR. A target gene miR-96-5p was selected using TargetScan, miRTarBase, miRDB databases. The combination of miR-96-5p and ZDHHC5 was verified by luciferase receptor assay. To further study the function and mechanism of miR-96-5p, we treated MGC-803 cells with miR-96-5p inhibitor and si-ZDHHC5, then detected cell viability, apoptosis, migration and invasion ability, as well as the expression of ZDHHC5, Bcl-2, Bax, cleaved caspase-3, cleaved caspase-9, and COX-2 by Western blot.

Results: Compared with adjacent normal samples, the levels of miR-96-5p, miR-222-5p, and miR-652-5p were remarkably increased, while miR-125-5p, miR-145-3p, and miR-379-3p were significantly reduced in GAC tumor samples (P<0.01), which were consistent with bioinformatics analysis. Furthermore, ZDHHC5 was defined as a direct target gene of miR-96-5p. miR-96-5p silence significantly reduced cell viability, increased cell apoptosis, and suppressed cell migration and invasion, as well as inhibited the expression of Bcl-2 and COX-2 and promoted Bax, cleaved caspase-3 and cleaved caspase-9 level in MGC-803 cells (P<0.01). Notably, ZDHHC5 silence reversed the inhibiting effects of miR-96-5p on MGC-803 cells growth and metastasis

Conclusion: Our findings identified six microRNAs (miRNAs; miR-96-5p, miR-222-5p, miR-652-5p, miR-125-5p, miR-145-3p, and miR-379-3p) related to GAC prognosis, and suggested that down-regulated miR-96-5p might inhibit tumor cell growth and metastasis via increasing ZDHHC5 expression enhance MGC-803 cell apoptosis, as well as decrease MGC-803 cell metastasis.

Screening of miRNAs as Prognostic Biomarkers for Colon Adenocarcinoma and Biological Function Analysis of Their Target Genes

We constructed a prognostic risk model for colon adenocarcinoma (COAD) using microRNAs (miRNAs) as biomarkers. Clinical data of patients with COADs and miRNA-seq data were from TCGA, and the differential expression of miRNAs (carcinoma vs. para-carcinoma tissues) was assessed using R software. COAD data were randomly divided into Training and Testing Sets. A linear prognostic risk model was constructed using Cox regression analysis based on the Training Set. Patients were classified as high-risk or low-risk according to the score of the prognostic model. Survival analysis and receiver operating characteristic (ROC) curves were used to evaluate model performance. The gene targets in the prognostic model were identified and their biological functions were analyzed. Analysis of COAD and normal cell lines using qPCR was used to verify the model. There were 134 up-regulated and 140 down-regulated miRNAs. We used the Training Set to develop a prognostic model based on the expression of seven miRNAs. ROC analysis indicated this model had acceptable prediction accuracy (area under the curve=0.784). Kaplan-Meier survival analysis showed that overall survival was worse in the high-risk group. Cox regression analysis showed that the 7-miRNA Risk Score was an independent prognostic factor. The 2,863 predicted target genes were mainly enriched in the MAPK, PI3K-AKT, proteoglycans in cancer, and mTOR signaling pathways. For unknown reasons, expression of these miRNAs in cancerous and normal cells differed somewhat from model predictions. Regardless, the 7-miRNA Risk Score can be used to predict COAD prognosis and may help to guide clinical treatment.

Expression of TOB/BTG family members in patients with inflammatory bowel disease

In recent years, the role of anti-proliferative TOB proteins in the regulation of immune response by inhibiting T cell activation has been demonstrated. Nevertheless, no previous studies have explored their expression in patients with IBD. The aim of the study was to characterize the gene and protein expression of the TOB/BTG family in intestinal tissue of patients with IBD. This is an observational and cross-sectional study that included 63 IBD patients. Gene expression of TOB/BTG family was measured by RT-PCR. Protein expression of TOB/CD16 and BTG/Ki-67 was evaluated by immunohistochemistry. TOB/BTG family mRNAs were detected and quantitated by RT-qPCR in rectal and ileum biopsies from UC patients and CD patients, respectively, and non-inflammatory control tissues. Results showed that TOB1 and BTG1 gene expression was decreased in the colonic mucosa from patients with UC compared with the control group. The TOB2 and BTG2 genes were over-expressed in the colonic mucosa of patients with UC in remission compared with the active UC and control group. The high TOB2 gene expression was associated with histological remission (P = .01). TOB1/CD16, TOB2/CD16, BTG1/Ki-67, BTG2/Ki-67 and BTG4/Ki-67 single and double positive cells were mostly NK, macrophages, epithelial cells, connective tissue cells and perivascular inflammatory infiltrates in tissues from patients with UC and CD. This is the first depiction of the TOB/BTG family gene and protein expression in rectal and ileum tissues by a CD16⁺ subpopulation in IBD.

Identification of Serum microRNA-25 as a novel biomarker for pancreatic cancer

To identify serum microRNA-25 (miR-25) as a diagnostic biomarker for pancreatic cancer (PCa) and to evaluate its supplementary role with serum carbohydrate antigen 19-9 (CA19-9) in early identification of cancers.Eighty patients with pancreatic cancer and 91 non-cancer controls were enrolled in this study. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression level of miR-25. Levels of CA19-9, carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125) were measured by chemiluminescent immunoassay. The logistic model was established to evaluate the correlation of miR-25 with clinical characteristics. A risk model for PCa was conducted by R statistical software. Diagnostic utility for PCa and correlation with clinical characteristics were analyzed.The expression level of miR-25, in the PCa group was significantly higher (P < .05). Risk Model illustrated the relation between miR-25 and pancreatic cancer. With the combination of CA19-9, the performance of miR-25 in early stages (I+II) in the diagnosis of PCa was profoundly better than CA19-9 and miR-25 alone. This combination was more effective for discriminating PCa from non-cancer controls (AUC-ROC, 0.985; sensitivity, 97.50%; specificity, 90.11%) compared with CA19-9 alone or the combination of CA19-9 and CA125.The expression level of miR-25 among pancreatic cancer patients was significantly higher than that in the control group. miR-25 existed as one of the most relevant factors of PCa. miR-25 can serve as a novel noninvasive approach for PCa diagnosis, and with the supplementary of CA19-9, the combination was more effective, especially in early tumor screening.

MiR-30a suppresses metastasis of gastric adenocarcinoma via targeting FAPα

BACKGROUND

Gastric cancer is one of the leading causes of death worldwide. MicroRNA-30a (miR-30a) has been demonstrated to be involved in several types of cancer development.

OBJECTIVE

We aimed to identify the molecular mechanism of miR-30a in gastric cancer.

METHODS

We investigated the expression of miR-30a in gastric cancer tissues by qRT-PCR. The role of miR-30a on the metastasis and proliferation of gastric cancer was evaluated by cell migration assay, CCK-8 assay and tumor peritoneal dissemination model. The target of miR-30a in gastric cancer was identified.

RESULTS

We discovered that miR-30a was significantly downregulated in gastric cancer tissues compared with adjacent nonmalignant tissues. The expression of miR-30a was inversely correlated with progression of gastric cancer. Gain- and loss-of function revealed that miR-30a acted as a potent tumor suppressor in gastric cancer. Re-expressed miR-30a inhibited gastric cancer cells migration, knock down miR-30a have the opposite effects. Furthermore, overexpression of miR-30a suppressed tumor peritoneal dissemination in vivo. We identified that fibroblast activation protein α (FAPα) was a direct target of miR-30a. The relative expression of FAPα was significantly higher in gastric cancer tissues compared with adjacent nonmalignant tissues. Inhibition of FAPα could recapitulate the effects of miR-30a, and overexpression of FAPα could abrogate the effect of miR-30a.

CONCLUSION

MiR-30a inhibited gastric cancer metastasis by targeting FAPα, suggesting that miR-30a may function as a novel tumor suppressor in gastric cancer.

Transfer of microRNA-25 by colorectal cancer cell-derived extracellular vesicles facilitates colorectal cancer development and metastasis

Cancer cell-derived extracellular vesicles (EVs) have been reported to promote the progression of colorectal cancer (CRC), although the regulatory mechanism remains uncharacterized. In this study, we investigated the role of microRNA-25 (miR-25)/sirtuin 6 (SIRT6) in the contribution of EVs derived from CRC cells to progression of CRC. In a co-culture system with EVs from HCT116 and NCM460 cells, the viability, migratory, and invasive properties of SW480 and SW620 cells were evaluated by cell counting kit-8 (CCK-8) and Transwell assays. Luciferase, chromatin immunoprecipitation (ChIP), and RNA immunoprecipitation (RIP) assays were conducted to verify the interaction among miR-25, SIRT6, lin-28 homologB (Lin28b), and neuropilin-1 (NRP-1). It was established that HCT116 cell-derived EVs promoted the malignant properties of SW480 cells and SW620 cells by delivering miR-25. SIRT6 was targeted by miR-25, whereas SIRT6 inhibited NRP-1 through downregulation of Lin28b. The tumor-bearing nude mouse experiments substantiated that HCT116 cell-derived EVs transferred miR-25 to facilitate tumor formation and metastasis by inhibiting SIRT6. In summary, our study clarifies the involvement of miR-25-targeted SIRT6 inhibition and SIRT6-mediated inhibition of the Lin28b/NRP-1 axis in CRC cell-derived EVs to CRC progression and metastasis.

miR-25-3p inhibition impairs tumorigenesis and invasion in gastric cancer cells in vitro and in vivo

Deregulated expression of microRNAs (miRNAs) plays a role in the pathogenesis and progression of gastric cancer (GC). Among upregulated miRNAs, miR-25-3p has oncogenic potential and therefore represents an attractive target for the treatment of GC. Here, we investigated the role of miR-25-3p on GC cells in vitro and in vivo. We found that miR-25-3p overexpression significantly promoted growth and invasion of gastric cancer cells in vitro. Conversely, targeting miR-25-3p triggered significant inhibition of growth, invasion and migration in GC cells in vitro. In vivo delivery of miR-25-3p inhibitors induced significant anti-tumor activity in SCID mice bearing human GC xenografts. Our findings showed the evidence that in vivo antagonism of miR-25-3p impaired tumorigenesis, providing the rationale for clinical development of miR-25-3p inhibitors in GC.

Identification of inflammation‑associated circulating long non‑coding RNAs and genes in intracranial aneurysm rupture‑induced subarachnoid hemorrhage

Ruptured intracranial aneurysm (IA)-induced subarachnoid hemorrhage (SAH) triggers a series of immune responses and inflammation in the brain and body. The present study was conducted to identify additional circulating biomarkers that may serve as potential therapeutic targets for SAH-induced inflammation. Differentially expressed (DE) long non-coding RNAs (lncRNAs; DElncRNAs) and genes (DEGs) in the peripheral blood mononuclear cells between patients with IA rupture-induced SAH and healthy controls were identified in the GSE36791 dataset. DEGs were used for weighted gene co-expression network analysis (WGCNA), and SAH-associated WGCNA modules were identified. Subsequently, an lncRNA-mRNA regulatory network was constructed using the DEGs in SAH-associated WGCNA modules. A total of 25 DElncRNAs and 1,979 DEGs were screened from patients with IA-induced SAH in the GSE36791 dataset compared with the controls. A total of 11 WGCNA modules, including four upregulated modules significantly associated with IA rupture-induced SAH were obtained. The DEGs in the SAH-associated modules were associated with Gene Ontology biological processes such as ‘regulation of programmed cell death’, ‘apoptosis’ and ‘immune response’. The subsequent lncRNA-mRNA regulatory network included seven upregulated lncRNAs [HCG27, ZNFX1 antisense RNA 1, long intergenic non-protein coding RNA (LINC)00265, murine retrovirus integration site 1 homolog-antisense RNA 1, cytochrome P450 1B1-AS1, LINC01347 and LINC02193] and 375 DEGs. Functional enrichment analysis and screening in the Comparative Toxicogenomics Database demonstrated that SAH-associated DEGs, including neutrophil cytosolic factor (NCF)2 and NCF4, were enriched in ‘chemokine signaling pathway’ (hsa04062), ‘leukocyte transendothelial migration’ (hsa04670) and ‘Fc gamma R-mediated phagocytosis’ (hsa04666). The upregulated lncRNAs and genes, including NCF2 and NCF4, in patients with IA rupture-induced SAH indicated their respective potentials as anti-inflammatory therapeutic targets.

Circular RNA circ-PVT1 contributes to paclitaxel resistance of gastric cancer cells through the regulation of ZEB1 expression by sponging miR-124-3p

Gastric cancer (GC) is the fifth most commonly diagnosed malignancy. Paclitaxel (PTX) is an effective first-line chemotherapy drug in GC treatment, but the resistance of PTX attenuates the therapeutic effect. Circular RNA circ-PVT1 can exert the oncogenic effect in GC. But the function of circ-PVT1 involved in PTX resistance of GC is still unknown. In the present study, the expression levels of circ-PVT1, miR-124-3p and ZEB1 in PTX-resistant GC tissues and cells were detected by quantitative real-time polymerase chain reaction (RT-qPCR). PTX resistance in PTX-resistant cells was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The protein levels of Zinc finger E-box binding homeobox 1 (ZEB1), P-glycoprotein (P-gp) and glutathione S-transferase (GST-π) were detected by Western blot assay. Cell apoptosis and invasion were measured in PTX-resistant cells by flow cytometry and transwell invasion assays, severally. The interaction between miR-124-3p and circ-PVT1 or ZEB1 was predicted by starBase software, and then verified by the dual-luciferase reporter assay. The role of circ-PVT1 in PTX resistance of GC in vivo was measured by xenograft tumor model. Our results showed that circ-PVT1 expression was up-regulated in PTX-resistant GC tissues and cells. Circ-PVT1 down-regulation enhanced PTX sensitivity in PTX-resistant GC cells by negatively regulating miR-124-3p. ZEB1 served as a direct target of miR-124-3p. Circ-PVT1 enhanced ZEB1 expression by sponging miR-124-3p. Circ-PVT1 knockdown increased PTX sensitivity of GC in vivo. Taken together, our studies disclosed that circ-PVT1 facilitated PTX resistance by up-regulating ZEB1 mediated via miR-124-3p, suggesting an underlying therapeutic strategy for GC.

MiR-596 activated by EP300 controls the tumorigenesis in epithelial ovarian cancer by declining BRD4 and KPNA4

Background

Epithelial ovarian cancer (EOC), a subclass of ovarian cancer (OC), is usually diagnosed at advanced stages due to the lack of effective screening means. Mounting reports have disclosed the vitally important roles of microRNAs (miRNAs) in carcinogenesis. Here, we aimed to find out possible miRNAs participating in EOC development.

Methods

qRT-PCR ad western blot respectively examined the mRNA and protein levels of studied genes. CCK-8, colony formation, flow cytometry, TUNEL and spheroid formation assays were appropriately employed for examining cell proliferation, cell cycle, apoptosis and stemness. The interaction between molecules was affirmed by luciferase reporter, RNA pull down and ChIP assays.

Results

In consistent with the observation of a past study, miR-596 expression was relatively low in EOC cells. Up-regulating miR-596 suppressed EOC cell proliferation and stemness. EP300 transcriptionally activated miR-596 to serve as a tumor-repressor in EOC. Then BRD4 and KPNA4, whose knockdown led to restraining effects on cell growth and stemness, were both revealed to be targeted by miR-596 in EOC. Lastly, rescue assays affirmed the tumor-restraining role of miR-596-BRD4/KPNA4 axis in EOC.

Conclusion

EP300-activated miR-596 hampered cell growth and stemness via targeting BRD4 and KPNA4 in EOC, proofing miR-596 as a promising therapeutic target in treating EOC patients.

Non-coding RNAs in gastric cancer

Non-coding RNAs (ncRNAs) are functional RNA molecules that play crucial regulatory roles in many fundamental biological processes. The dysregulation of ncRNAs is significantly associated with the progression of human cancers, including gastric cancer. In this review, we have summarized the oncogenic or tumor-suppressive roles and the regulatory mechanisms of lncRNAs, miRNAs, circRNAs and piRNAs, and have discussed their potential as biomarkers or therapeutic targets in gastric cancer.

Downregulation of lncRNA PMS2L2 in patients with gastric adenocarcinoma predicts poor prognosis

Long non-coding RNA PMS1 homolog 2 mismatch repair system component pseudogene 2 (PMS2L2) is a key player in lipopolysaccharide-induced inflammatory responses. Preliminary deep sequencing data revealed that PMS2L2 was downregulated in gastric adenocarcinoma (GA) tissues compared with healthy adjacent tissues and the aim of the present study was to investigate the role of PMS2L2 in GA. In the present study, reverse transcription-quantitative PCR assays were performed to analyze gene expression. Cell transfections were performed to analyze gene interactions and Transwell assays were performed to analyze cell invasion and migration. The results revealed that PMS2L2 expression was downregulated in cancer tissues obtained from patients with GA compared with healthy adjacent tissues and was not significantly affected by clinical stage. Furthermore, low levels of PMS2L2 in cancer tissues were closely associated with a low overall 5-year survival rate in patients. MicroRNA (miR)-25 was upregulated in GA tissues compared with healthy adjacent tissues and inversely associated with PMS2L2 levels. In GA cells in vitro, overexpression of PMS2L2 downregulated the expression of miR-25, while miR-25 overexpression did not significantly affect PMS2L2 expression. Furthermore, PMS2L2 overexpression inhibited the migration and invasion of GA cells. miR-25 overexpression partially rescued the decreased migration and invasion of GA cells caused by PMS2L2 overexpression. Therefore, PMS2L2 may downregulate miR-25 expression to inhibit GA.

MicroRNA-424-5p inhibits the proliferation, migration, and invasion of nasopharyngeal carcinoma cells by decreasing AKT3 expression

This study examined the expression and potential mechanism of microRNA (miRNA)-424-5p in nasopharyngeal carcinoma (NPC). NPC tissues were collected from 40 patients who were enrolled in the study, and skin samples were collected from 26 healthy subjects during plastic surgery as controls. We performed various in vitro assays using miR-424-5p to examine its function in primary NPC-1 cells. Bioinformatics was employed to analyze potential target genes and signaling pathways of miR-424-5p. We found that miR-424-5p expression in NPC tissues is downregulated and negatively correlated with lymph node metastasis and clinical staging. Expression of miR-424-5p in NPC cells was also downregulated, and transfection with miR-424-5p mimics inhibited proliferation, migration, and invasion of NPC-1 cells. Bioinformatics identified the AKT3 gene as a potential target of miR-424-5p and dual luciferase assays confirmed this finding. Upregulation of AKT3 expression rescued the inhibitory effect of miR-424-5p on the proliferation, migration, and invasion. Our results suggest that miR-424-5p inhibited the proliferation, migration, and invasion of NPC cells by decreasing AKT3 expression.

miR-25 expression is upregulated in pancreatic ductal adenocarcinoma and promotes cell proliferation by targeting ABI2

MicroRNAs (miRNAs) are reported to play a critical role in the regulation of cancer cell proliferation; however, the role of microRNA-25 (miR-25) in pancreatic ductal adenocarcinoma (PDAC) remains unclear. In the present study, the role of miR-25 in PDAC cell proliferation was investigated. Upregulated expression of miR-25 was found in PDAC tissues and cell lines by reverse transcription-quantitative PCR. Cell proliferation was significantly enhanced by overexpression of miR-25 as shown by CCK-8 assay results. Meanwhile, overexpression of miR-25 also promoted G1-to-S phase transition of the cell cycle in Aspc-1 cells via flow cytometry analysis. However downregulation of miR-25 inhibited the tumor cell proliferation and cell cycle transition. Online software was used to predict the target gene for miR-25 and luciferase reporter assay confirmed that Abl interactor 2 (ABI2) was a target of miR-25 via direct binding of its 3' untranslated region with miR-25. Moreover, results of the western blot analysis demonstrated that miR-25 negatively regulated the expression of ABI2 at the protein level. In addition, introduction of ABI2 mRNA into cells overexpressing miR-25 attenuated the carcinogenic effects of miR-25. In conclusion, these findings demonstrate that miR-25 plays an oncogenic role and promotive role in PDAC cell proliferation via targeting of ABI2.

Long Noncoding RNA Lnc-TLN2-4:1 Suppresses Gastric Cancer Metastasis and Is Associated with Patient Survival

Gastric cancer (GC) is one of the most common malignancies worldwide, and the tumor metastasis leads to poor outcomes of GC patients. Long noncoding RNAs (lncRNAs) have emerged as new regulatory molecules that play a crucial role in tumor metastasis. However, the biological function and underlying mechanism of numerous lncRNAs in GC metastasis remain largely unclear. Here, we report a novel lncRNA, lnc-TLN2-4:1, whose expression is decreased in GC tissue versus matched normal tissue, and its low expression is involved in the lymph node and distant metastases of GC, as well as poor overall survival rates of GC patients. We further found that lnc-TLN2-4:1 inhibits the ability of GC cells to migrate and invade but does not influence GC cell proliferation and confirmed that lnc-TLN2-4:1 is mainly located in the cytoplasm of GC cells. We then found that lnc-TLN2-4:1 increases the mRNA and protein expression of TLN2 in GC cells and there is a positive correlation between the expression of lnc-TLN2-4:1 and TLN2 mRNA in GC tissue. Collectively, we identified a novel lncRNA, lnc-TLN2-4:1, in GC, where lnc-TLN2-4:1 represses cell migration and invasion. The low expression of lnc-TLN2-4:1 is associated with poor overall survival rates of GC patients. These suggest that lnc-TLN2-4:1 may be a tumor suppressor during GC metastasis.

Analyses of non-coding somatic drivers in 2,658 cancer whole genomes

The discovery of drivers of cancer has traditionally focused on protein-coding genes1-4. Here we present analyses of driver point mutations and structural variants in non-coding regions across 2,658 genomes from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium5 of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). For point mutations, we developed a statistically rigorous strategy for combining significance levels from multiple methods of driver discovery that overcomes the limitations of individual methods. For structural variants, we present two methods of driver discovery, and identify regions that are significantly affected by recurrent breakpoints and recurrent somatic juxtapositions. Our analyses confirm previously reported drivers6,7, raise doubts about others and identify novel candidates, including point mutations in the 5' region of TP53, in the 3' untranslated regions of NFKBIZ and TOB1, focal deletions in BRD4 and rearrangements in the loci of AKR1C genes. We show that although point mutations and structural variants that drive cancer are less frequent in non-coding genes and regulatory sequences than in protein-coding genes, additional examples of these drivers will be found as more cancer genomes become available.

MiR-96-5p inhibition induces cell apoptosis in gastric adenocarcinoma

BACKGROUND

Gastric adenocarcinoma (GAC) mortality rates have remained relatively changed over the past 30 years, and it continues to be one of the leading causes of cancer-related death.

AIM

To search for novel miRNAs related to GAC prognosis and further investigate the effect of miR-96-5p on MGC-803 cells.

METHODS

The miRNA expression profile data of GAC based on The Cancer Genome Atlas were obtained and used to screen differently expressed miRNAs (DEMs) and DEMs related to GAC prognosis. Then, the expression of DEMs related to GAC prognosis was identified in GAC tumor samples and adjacent normal samples by qRT-PCR. The target gene, ZDHHC5, of miR-96-5p was predicted using TargetScan, miRTarBase, and miRDB databases and confirmed by luciferase reporter assay. Furthermore, MGC-803 cells were transfected with inhibitor NC, miR-96-5p inhibitor, si-ZDHHC5, or miR-96-5p inhibitor + si-ZDHHC5, and then cell apoptosis was detected by flow cytometry. The expression of ZDHHC5, Bcl-2, and COX-2 was detected using western blotting.

RESULTS

A total of 299 DEMs and 35 DEMs related to GAC prognosis were screened based on The Cancer Genome Atlas. Then compared with adjacent normal samples, the levels of miR-96-5p, miR-222-5p, and miR-652-5p were remarkably increased, while miR-125-5p, miR-145-3p, and miR-379-3p levels were reduced in GAC tumor samples (P < 0.01), which were consistent with bioinformatics analysis. Furthermore, ZDHHC5 was defined as a direct target gene of miR-96-5p. miR-96-5p inhibition increased the number of apoptotic cells as well as promoted the expression of ZDHHC5, Bcl-2, and COX-2 in MGC-803 cells (P < 0.01). After ZDHHC5 inhibition, the number of apoptotic cells and the expression of ZDHHC5, Bcl-2, and COX-2 were reduced. The addition of an miR-96-5p inhibitor partly reversed these effects (P < 0.01).

CONCLUSION

Our findings identified six miRNAs related to GAC prognosis and suggested that downregulated miR-96-5p might induce cell apoptosis via upregulating ZDHHC5 expression in MGC-803 cells.

Decreased expression of miR-410-3p correlates with poor prognosis and tumorigenesis in human glioma

Background

Gliomas are the most common type of primary tumors in the central nervous system. This study aimed to investigate the biological role of miR-410-3p in glioma and elucidate the potential molecular mechanisms involved.

Methods

The expression levels of miR-410-3p in clinical tissue samples and glioma cell lines were determined using qRT-PCR analysis. The clinical significance of miR-410-3p in glioma was evaluated using Kaplan-Meier survival analysis and Fisher’s exact test. The effects of miR-410-3p on glioma cell proliferation, apoptosis, migration and invasion were investigated using MTT assays, flow cytometry, transwell migration and invasion assays. Besides, corresponding mechanistic studies were carried out.

Results

miR-410-3p was significantly down-regulated in glioma tissues. Besides, Kaplan-Meier analysis demonstrated that patients with low miR-410-3p expression had a shorter overall survival. Decreased miR-410-3p expression was associated with larger tumor size, lower Karnofsky performance score (KPS), and higher World Health Organization (WHO) grade. Over-expression of miR-410-3p suppressed cell proliferation, migration, and invasion, and accelerated apoptosis; whereas depletion of miR-410-3p facilitated cell proliferation, migration, and invasion, and inhibited apoptosis. Mechanistic investigations demonstrated that Ras-related protein 1A (RAP1A) was a direct target of miR-410-3p, and that rescue of RAP1A expression reversed miR-410-3p over-expression-induced inhibitory effects on cell proliferation, migration, and invasion. Notably, miR-410-3p over-expression repressed tumor growth in mouse xenograft models.

Conclusion

Our findings indicate that miR-410-3p functions as a tumor suppressor in glioma by directly targeting RAP1A. Thus, this study may provide some new insights into gliomagenesis and progression.

MicroRNA-330-3p promotes brain metastasis and epithelial-mesenchymal transition via GRIA3 in non-small cell lung cancer

Brain metastasis (BM) is associated with poor prognosis in patients with non-small cell lung cancer (NSCLC). We sought to identify microRNAs (miRNAs) that could serve as biomarkers to differentiate NSCLC patients with and without BM. Logistic regression was conducted with 122 NSCLC patients (60 without BM, 62 with BM) to assess the association between miRNAs and BM. We confirmed several risk factors for BM and revealed that serum miR-330-3p levels are higher in NSCLC patients with BM than that without BM. Overexpression of miR-330-3p promoted proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of NSCLC cells in vitro and NSCLC tumorigenesis in vivo. Knocking down miR-330-3p suppressed this metastatic phenotype. We identified putative miR-330-3p target genes by comparing mRNA microarray analysis data from A549 cells after miR-330-3p knockdown with candidate miR-330-3p target genes predicted by public bioinformatic tools and luciferase reporter assays. We found that GRIA3 is a target of miR-330-3p and that miR-330-3p stimulates EMT progress by mediating GRIA3-TGF-β1 interaction. Our results provide novel insight into the role of miR-330-3p in NSCLC metastasis, and suggest miR-330-3p may be a useful biomarker for identifying NSCLC with metastatic potential.

Long non-coding RNA GATA6-AS inhibits gastric cancer cell proliferation by downregulating microRNA-25-3p

The abnormal growth of endothelial cells is involved in several types of diseases, including gastric cancer. The long non-coding RNA GATA6-AS is a key regulator of endothelial cell growth and may therefore also play an important role in gastric cancer. In the present study it was found that GATA6-AS was downregulated in tumor tissues compared with adjacent normal tissues. Moreover, plasma levels of GATA6-AS were linearly associated with GATA6-AS expression levels in tumor tissues and not in normal tissues. MicroRNA (miR)-25-3p was upregulated in tumor tissues compared with adjacent normal tissues and was inversely associated with GATA6-AS in tumor tissues only. The overexpression of miR-25-3p in gastric cancer cells resulted in no significant changes in the expression levels of GATA6-AS, whereas overexpression of GATA6-AS led to significantly downregulated miR-25-3p levels. Furthermore, overexpression of GATA6-AS inhibited cancer cell proliferation, with no effect on migration and invasion. The overexpression of miR-25-3p resulted in increased proliferation of cancer cells and attenuated the effects of GATA6-AS overexpression. Thus, it is postulated that GATA6-AS inhibits proliferation of gastric cancer cells by downregulating miR-25-3p.

Identification of the association between rs41274221 polymorphism in the seed sequence of microRNA-25 and the risk of neonate sepsis

BACKGROUND

Many studies have investigated the role of microRNA-25 (miR-25) in the initiation and progression of sepsis in newborns. In this study, we aim to explore how rs41274221 polymorphism in miR-25 compromises the interaction between miR-25 and CD69, so as to understand the mechanisms involved in the control of sepsis in newborns.

METHODS

Computational analysis, luciferase assay, real-time polymerase chain reaction (PCR), and western blot analysis were performed in this study.

RESULTS

The luciferase assays results showed that CD69 was a target gene of miR-25, because the luciferase activity in cells transfected with wild type CD69 was much lower than that in the cells transfected with mutant CD69 or the scramble control. Real-time PCR and western blot analysis results showed that the expression of miR-25 in sepsis patients was significantly upregulated as compared with that in the normal control group, and the CD69 position ratio as well as the messenger RNA (mRNA) and protein level of CD69 in sepsis patients was much higher than those in the normal control group. As compared with the scramble control, miR-25 mimics, and CD69 small interfering RNA (siRNA) downregulated the mRNA and protein expression of CD69, whereas the expression of CD69 mRNA and protein in cells transfected with miR-25 inhibitors was significantly higher as compared with that in the scramble control. In addition, interferonγ production was significantly downregulated in cells transfected with miR-25 inhibitors but notably upregulated in cells transfected with miR-25 mimics or CD69 siRNA.

CONCLUSION

The single-nucleotide polymorphism (SNP; rs41274221) in miR-25 is associated with the risk of sepsis in newborns.

Overexpression of miR-25 is associated with progression and poor prognosis of cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare but highly aggressive type of malignancy. MicroRNA (miR)-25 has been demonstrated to be involved in the genesis of numerous cancer types. The aim of the present study was to investigate the prognostic value and functional role of miR-25 in CCA. The expression of miR-25 was determined by reverse transcription-quantitative (RT-q)PCR. The association between miR-25 expression and clinicopathological features was analyzed using the χ² test. Kaplan-Meier survival analysis and Cox linear regression were performed to explore the prognostic value of miR-25. The effects of miR-25 on the biological behavior of CCA cells were determined using loss-and gain-of-function experiments in CCA cell lines. Upregulated miR-25 expression was observed in CCA tissues and cell lines compared with that in the respective controls (all P<0.05). Patients with high expression of miR-25 in CCA tissues had a comparatively higher tumor-nodes-metastasis stage (P=0.026), a higher rate of lymph node metastasis (P=0.032) and a shorter overall survival rate (log-rank P=0.022). miR-25 was determined to be an independent prognostic factor for CCA patients (P=0.036). In vitro, transfection with miR-25 inhibitor suppressed cell viability, migration and invasion, while miR-25 mimics had the opposite effect. These results indicated that miR-25 functions as an oncogene and is involved in tumor progression in CCA. miR-25 may serve as a prognostic biomarker and a potential therapeutic target for CCA treatment.

Overexpression of long noncoding RNA GAS5 suppresses tumorigenesis and development of gastric cancer by sponging miR-106a-5p through the Akt/mTOR pathway

Long noncoding RNAs (lncRNAs) have emerged as important regulators of human cancers. LncRNA GAS5 (GAS5) is identified as a tumor suppressor involved in several cancers. However, the roles of GAS5 and the mechanisms responsible for its functions in gastric cancer (GC) have not been well documented. Herein, the decreased GAS5 and increased miRNA-106a-5p levels were observed in GC and cell lines. GAS5 level was significantly inversely correlated with miRNA-106a-5p level in GC tissues. Moreover, dual-luciferase reporter and qRT-PCR assays showed that GAS5 bound to miRNA-106a-5p and negatively regulated its expression in GC cells. Functional experiments showed that GAS5 overexpression suppressed GC cell proliferation, migration and invasion capabilities, and promoted apoptosis, while miRNA-106a-5p overexpression inverted the functional effects induced by GAS5 overexpression. In vivo, GAS5 overexpression inhibited tumor growth by negatively regulating miRNA-106a-5p expression. Mechanistic investigations revealed that GAS5 overexpression inactivated the Akt/mTOR pathway by suppressing miRNA-106a-5p expression in vitro and in vivo. Taken together, our findings conclude the GAS5 overexpression suppresses tumorigenesis and development of gastric cancer by sponging miR-106a-5p through the Akt/mTOR pathway.

Summary: GAS5, a tumor suppressor, was confirmed to suppress tumorigenesis and development of gastric cancer by sponging miR-106a-5p through the Akt/mTOR pathway, which provides a novel regulatory axis of GC progression.

miRNome Reveals New Insights Into the Molecular Biology of Field Cancerization in Gastric Cancer

BACKGROUND

MicroRNAs (miRNAs) play an important role in gastric carcinogenesis and have been associated with gastric field cancerization; however, their role is not fully understood in this process. We performed the miRNome sequencing of non-cancerous, adjacent to tumor and gastric cancer samples to understand the involvement of these small RNAs in gastric field cancerization.

METHODS

We analyzed samples of patients without cancer as control (non-cancerous gastric samples) and adjacent to cancer and gastric cancer paired samples, and considered miRNAs with |log2(fold change)| > 2 and Padj < 0.05 to be statistically significant. The identification of target genes, functional analysis and enrichment in KEGG pathways were realized in the TargetCompare, miRTargetLink, and DAVID tools. We also performed receiver operating characteristic (ROC) curves and miRNAs that had an AUC > 0.85 were considered to be potential biomarkers.

RESULTS

We found 14 miRNAs exclusively deregulated in gastric cancer, of which six have potential diagnostic value for advanced disease. Nine miRNAs with known tumor suppressor activities (TS-miRs) were deregulated exclusively in adjacent tissue. Of these, five have potential diagnostic value for the early stages of gastric cancer. Functional analysis of these TS-miRs revealed that they regulate important cellular signaling pathways (PI3K-Akt, HIF-1, Ras, Rap1, ErbB, and MAPK signaling pathways), that are involved in gastric carcinogenesis. Seven miRNAs were differentially expressed in both gastric cancer and adjacent regarding to non-cancerous tissues; among them, hsa-miR-200a-3p and hsa-miR-873-5p have potential diagnostic value for early and advanced stages of the disease. Only hsa-miR-196a-5p was differentially expressed between adjacent to cancer and gastric cancer tissues. In addition, the other miRNAs identified in this study were not differentially expressed between adjacent to cancer and gastric cancer, suggesting that these tissues are very similar and that share these molecular changes.

CONCLUSION

Our results show that gastric cancer and adjacent tissues have a similar miRNA expression profile, indicating that studied miRNAs are intimately associated with field cancerization in gastric cancer. The overexpression of TS-miRs in adjacent tissues may be a barrier against tumorigenesis within these pre-cancerous conditions prior to the eventual formation or relapse of a tumor. Additionally, these miRNAs have a great accuracy in discriminating non-cancerous from adjacent to tumor and cancer tissues and can be potentially useful as biomarkers for gastric cancer.

miR-25 Promotes Cell Proliferation, Migration, and Invasion of Non-Small-Cell Lung Cancer by Targeting the LATS2/YAP Signaling Pathway

Metastasis is the leading cause of high mortality in lung cancer patients, and metastatic lung cancer is difficult to treat. miRNAs are involved in various biological processes of cancer, including metastasis. Our previous studies revealed that miR-25 promoted non-small-cell lung cancer (NSCLC) cell proliferation and suppressed cell apoptosis by directly targeting TP53 and MOAP1. In this work, we further explored the miR-25 expression in NSCLC patients in the Cancer Genome Atlas (TCGA) database and measured the miR-25 expression levels in the tissues of NSCLC patients and cell lines. miR-25 was overexpressed in both NSCLC tissues and cell lines. NSCLC patients who expressed a higher level of miR-25 exhibited worse overall survival than those with a lower level of miR-25. Overexpression of miR-25 enhanced NSCLC cell migration and invasion, while the inhibition of miR-25 exhibited the opposite effects. We identified the large tumor suppressor homology 2 (LATS2) as a new target gene of miR-25 in lung cancer. The effects of miR-25 on promoting NSCLC cell migration and invasion were at least partially due to activation of the Hippo signaling pathway. Additionally, miR-25 antagomir inhibited xenograft tumor growth and metastasis by the upregulation of LATS2. Taken together, our findings demonstrate that miR-25 contribute to lung cancer cell proliferation and metastasis by targeting the LATS2/YAP signaling pathway, which implicate miR-25 as a promising therapeutic target for lung cancer metastasis. Given that oxidative stress induces the overexpression of miR-25 and plays a critical role in cancer progression, this study establishes miR-25 as an intermediate between oxidative stress and lung cancer metastasis.

Overexpression of miRNA-25-3p inhibits Notch1 signaling and TGF-β-induced collagen expression in hepatic stellate cells

During chronic liver injury hepatic stellate cells (HSCs), the principal source of extracellular matrix in the fibrotic liver, transdifferentiate into pro-fibrotic myofibroblast-like cells - a process potentially regulated by microRNAs (miRNAs). Recently, we found serum miRNA-25-3p (miR-25) levels were upregulated in children with Cystic Fibrosis (CF) without liver disease, compared to children with CF-associated liver disease and healthy individuals. Here we examine the role of miR-25 in HSC biology. MiR-25 was detected in the human HSC cell line LX-2 and in primary murine HSCs, and increased with culture-induced activation. Transient overexpression of miR-25 inhibited TGF-β and its type 1 receptor (TGFBR1) mRNA expression, TGF-β-induced Smad2 phosphorylation and subsequent collagen1α1 induction in LX-2 cells. Pull-down experiments with biotinylated miR-25 revealed Notch signaling (co-)activators ADAM-17 and FKBP14 as miR-25 targets in HSCs. NanoString analysis confirmed miR-25 regulation of Notch- and Wnt-signaling pathways. Expression of Notch signaling pathway components and endogenous Notch1 signaling was downregulated in miR-25 overexpressing LX-2 cells, as were components of Wnt signaling such as Wnt5a. We propose that miR-25 acts as a negative feedback anti-fibrotic control during HSC activation by reducing the reactivity of HSCs to TGF-β-induced collagen expression and modulating the cross-talk between Notch, Wnt and TGF-β signaling.

Decreased expression levels of DAL-1 and TOB1 are associated with clinicopathological features and poor prognosis in gastric cancer

PURPOSE

We previously demonstrated that the functional inactivation of DAL-1 and TOB1 promotes an aggressive phenotype in gastric cancer cells, but the links between both genes and the survival of patients with gastric cancer are unknown. Here, we investigated the correlations of the expression levels of DAL-1 and TOB1 with the progression of gastric cancer.

METHODS

A total of 270 patients who underwent resectable gastrectomy were included. The expression of DAL-1 and TOB1 was detected by immunohistochemistry.

RESULTS

Low expression of DAL-1 in cancer tissue was significantly associated with tumor site (p < 0.05), histological grade (p < 0.01), depth of invasion (p < 0.05), lymph node metastasis status (p < 0.05), Lauren classification (p < 0.001), and clinical stage (p < 0.01). A lower level of TOB1 was observed in gastric cancer patients with diffuse type disease compared to patients with either intestinal or mixed type disease (p < 0.001). Additionally, Spearman's correlation analysis revealed that decreased expression of DAL-1 was positively correlated with low TOB1 expression (r=0.304, p < 0.001). The survival analysis showed that low levels of DAL-1 and TOB1 were significantly associated with poor survival of gastric cancer patients (p <0.001 and p < 0.05, respectively).

CONCLUSION

The downregulation of DAL-1 and TOB1 expression is associated with shorter survival of gastric cancer patients. Hence, DAL-1 and TOB1 may be considered potential novel markers for predicting the outcomes of patients with gastric cancer.

Circulating microRNA-133, microRNA-17 and microRNA-25 in serum and its potential diagnostic value in gastric cancer

Gastric cancer is one of the most common malignancies in the world and is considered as the most lethal gastrointestinal cancer. microRNAs (miRNAs) can be very important in detecting a disease at an early stage. The aim of this study was to investigate the microRNA-17 (miR-17), miR-25, and miR-133b in the serum of gastric cancer subjects. Serum samples were obtained from 120 gastric cancers and 102 healthy subjects. We evaluated expression levels of miR-17, miR-25 and miR-133b by quantitative real-time polymerase chain reaction. Our results showed that in the patients with gastric cancer, the expression level of miR-17 and miR-25 were significantly increased compared with the control group (P < 0.5), while the expression level of miR-133b was significantly decreased in patient groups compared with control cases (P < 0.5). It seems that expression of miRNAs in Iranian patients with gastric cancer is similar to other patients in other populations. These findings suggested that miR-17, miR-25 and miR-133b could be introduced as potential diagnostic candidates for the detection in gastric cancer patients in the early stage.

Identifying the differentially expressed microRNAs in esophagus squamous cell carcinoma of Kazakh patients in Xinjiang

Despite improvements in diagnosis and treatment, the survival of patients with advanced stages of esophageal squamous cell carcinoma (ESCC) remains poor. Therefore, novel biomarkers that can assist with early detection of ESCC are required. In the present study, three paired ESCC and normal esophageal tissue samples from Xinjiang Kazakh patients were obtained and microRNA (miRNA) microarray analysis was used to detect the differentially-expressed miRNAs. The target genes of the identified miRNAs were predicted using miRWalk software. A total of 23 miRNAs were differently expressed in Kazakh patients with ESCC. Gene Ontology enrichment analysis demonstrated that the upregulated miRNAs were predominantly associated with the 'vesicle' and 'membrane-bounded vesicle' terms, while the downregulated miRNAs were primarily associated with the term 'negative regulation of integrin-mediated signaling pathway'. The most highly enriched Kyoto Encyclopedia of Genes and Genomes pathway for the differentially-expressed miRNAs was 'Endocrine and other factor-regulated calcium reabsorption'. Protein-protein interaction network analysis revealed that IQ motif containing GTPase activating protein 1, RAB11A, lysine acetyltransferase 2B, catenin α 1 and tight junction protein 2 were hub genes of the network. In conclusion, a number of differentially-expressed miRNAs were identified in ESCC tissues samples from Xinjiang Kazakh patients, which may improve the understanding of the processes of tumorigenesis and development.

The miR-29c-KIAA1199 axis regulates gastric cancer migration by binding with WBP11 and PTP4A3

Gastric cancer (GC) is the second leading cause of death among patients with cancer in China. The primary reason of GC treatment failure is metastasis. Therefore, identifying metastatic biomarkers and clarifying the regulatory mechanisms involved in the GC metastatic process are important. Here, we found that KIAA1199, a cell migration-inducing protein, was significantly overexpressed in GC and correlated with lymph node metastasis and poorer patient survival. Additionally, the introduction of KIAA1199 dramatically promoted GC cell proliferation and migration in vitro and in vivo, and the inhibition of KIAA1199 suppressed GC cell growth and migration and induced GC cell apoptosis. Cell migration is a functional consequence of the epithelial-mesenchymal transition (EMT). In this study, we found that KIAA1199 inhibition or overexpression regulated the expression of E-cadherin and N-cadherin through KIAA1199 binding to WW domain binding protein 11 (WBP11) and protein tyrosine phosphatase type IVA, member 3 (PTP4A3) and through the subsequent activation of the FGFR4/Wnt/β-catenin and EGFR signaling pathways. More importantly, ectopic expression of WBP11 or PTP4A3 blocked the stimulatory effects of KIAA1199 on GC cell proliferation and migration. Meanwhile, we illustrated that KIAA1199 was a target gene of miR-29c-3p and that miR-29c-3p overexpression led to decreased migration of GC cells in vitro and in vivo by suppressing the expression of KIAA1199 and several key proteins in the Wnt/β-catenin and EGFR signaling pathways (e.g., WBP11, FGFR4, and PTP4A3). Taken together, these data demonstrate that KIAA1199 promotes GC metastasis by activating EMT-related signaling pathways and that miR-29c-3p regulates GC cell migration in vitro and in vivo by regulating KIAA1199 expression and activating the FGFR4/Wnt/β-catenin and EGFR signaling pathways. These findings provide a new understanding of GC development and progression and may provide novel therapeutic strategies for GC.

MiR-99a-5p inhibits bladder cancer cell proliferation by directly targeting mammalian target of rapamycin and predicts patient survival

Bladder cancer is a common malignancy and miR-99a-5p has been reported to be downregulated in bladder cancer, but its function and the underlying mechanism in bladder cancer development remains largely unclear. Here, we report that miR-99a-5p expression was decreased in bladder cancer compared with the adjacent normal tissues. Receiver operating characteristic curve revealed that miR-99a-5p expression signature had area under curve value of 0.7989 in differing bladder cancer from the adjacent normal tissues. Bladder cancer patients with low expression of miR-99a-5p had a poor survival rate. Gain-of-function and loss-of-function approaches demonstrated that miR-99a-5p inhibited bladder cell proliferation and cell cycle. Furthermore, we identified that mammalian target of rapamycin (mTOR) was a direct target of miR-99a-5p and mTOR restore could rescue the proliferative ability of bladder cancer cells. Moreover, miR-99a-5p/mTOR axis regulated S6K1 phosphorylation. These suggested that miR-99a-5p/mTOR axis might be a therapeutic target for bladder cancer.

Genome-wide identification of a novel miRNA-based signature to predict recurrence in patients with gastric cancer

The current tumor node metastasis (TNM) staging system is inadequate for identifying high-risk gastric cancer (GC) patients. Using a systematic and comprehensive-biomarker discovery and validation approach, we attempted to build a microRNA (miRNA)-recurrence classifier (MRC) to improve the prognostic prediction of GC. We identified 312 differentially expressed miRNAs in 446 GC tissues compared to 45 normal controls by analyzing high-throughput data from The Cancer Genome Atlas (TCGA). Using a Cox regression model, we developed an 11-miRNA signature that could successfully discriminate high-risk patients in the training set (n = 372; P < 0.0001). Quantitative real-time polymerase chain reaction-based validation in an independent clinical cohort (n = 88) of formalin-fixed paraffin-embedded clinical GC samples showed that MRC-derived high-risk patients succumb to significantly poor recurrence-free survival in GC patients (P < 0.0001). Cox and stratification analysis indicated that the prognostic value of this signature was independent of clinicopathological risk factors. Time-dependent receiver operating characteristic (ROC) analysis revealed that the area under the curve of this signature was significantly larger than that of TNM stage in the TCGA (0.733 vs. 0.589 at 3 years, P = 0.004; 0.802 vs. 0.635 at 5 years, P = 0.005) and validation cohort (0.835 vs. 0.689 at 3 years, P = 0.003). A nomogram was constructed for clinical use, which integrated both MRC and clinical-related variables (depth of invasion, lymph node status and distance metastasis) and did well in the calibration plots. In conclusion, this novel miRNA-based signature is superior to currently used clinicopathological features for identifying high-risk GC patients. It can be readily translated into clinical practice with formalin-fixed paraffin-embedded specimens for specific decision-making applications.

MiR-324-5p reduces viability and induces apoptosis in gastric cancer cells through modulating TSPAN8

OBJECTIVES

The purpose of this study was to further clarify the role and underlying mechanism of miR-324-5p in gastric cancer.

METHODS

The expressions of miR-324-5p and TSPAN8 as determined by qRT-PCR or Western blot were compared between the gastric cancer tissues and normal tissues. Human gastric cancer cell line SGC-7901 was cultured and transfected with miR-324-5p mimic/inhibitor or pcDNA-TSPAN8. The cell survival was assessed by the cell viability and apoptosis. Luciferase reporter gene assays were performed to explore the interaction between miR-324-5p and TSPAN8 in SGC-7901 cells.

KEY FINDINGS

MiR-324-5p was decreased in human gastric carcinoma tissues (n = 33), but TSPAN8 protein expression was increased in the gastric carcinoma tissues (n = 33). Moreover, miR-324-5p inhibited the viability and induced the apoptosis of gastric cancer cells in vitro. TSPAN8 is a functional target of miR-324-5p in gastric cancer. MiR-324-5p was further confirmed to reduce gastric cancer cell viability and induce apoptosis via downregulating TSPAN8 in SGC-7901 cells in vitro. Additionally, miR-324-5p overexpression markedly inhibited the tumorigenesis of gastric cancer cells in vivo, as shown by the smaller tumour volume compared with the control.

CONCLUSIONS

This study suggested a novel, probable mechanism of miR-324-5p in gastric cancer context and revealed that miR-324-5p inhibited gastric cancer cell survival by targeting TSPAN8.

The emerging roles of the polycistronic miR-106b∼25 cluster in cancer - A comprehensive review

MicroRNAs (miRNAs) are short, non-coding RNA molecules that regulate gene expression at the post-transcriptional level by inhibiting translation and decreasing the stability of the targeted transcripts. Over the last two decades, miRNAs have been recognized as important regulators of cancer cell biology, acting either as oncogenes or tumor suppressors. The polycistronic miR-106b∼25 cluster, located within an intron of MCM7 gene, consists of three highly conserved miRNAs: miR-25, miR-93 and miR-106b. A constantly growing body of evidence indicates that these miRNAs are overexpressed in numerous human malignancies and regulate multiple cellular processes associated with cancer development and progression, including: cell proliferation and survival, invasion, metastasis, angiogenesis and immune evasion. Furthermore, recent studies revealed that miR-106b∼25 cluster miRNAs modulate cancer stem cells characteristics and might promote resistance to anticancer therapies. In light of these novel discoveries, miRNAs belonging to the miR-106b∼25 cluster have emerged as key oncogenic drivers as well as potential biomarkers and plausible therapeutic targets in different tumor types. Herein, we comprehensively review novel findings on the roles of miR-106b∼25 cluster in human cancer, and provide a broad insight into the molecular mechanisms underlying its oncogenic properties.

MicroRNAs as non-invasive diagnostic biomarkers for gastric cancer: Current insights and future perspectives

Non-invasive diagnostic biomarkers may contribute to an early identification of gastric cancer (GC) and improve the clinical management. Unfortunately, no sensitive and specific screening biomarkers are available yet and the currently available approaches are limited by the nature of the disease. GC is a heterogenic disease with various distinct genetic and epigenetic events that occur during the multifactorial cascade of carcinogenesis. MicroRNAs (miRNAs) are commonly deregulated in gastric mucosa during the Helicobacter pylori infection and in stepwise manner from chronic gastritis, through preneoplastic conditions such as atrophic gastritis and intestinal metaplasia, to early dysplasia and invasive cancer. Identification of miRNAs in blood in 2008 led to a great interest on miRNA-based diagnostic, prognostic biomarkers in GC. In this review, we provide the most recent systematic review on the existing studies related to miRNAs as diagnostic biomarkers for GC. Here, we systematically evaluate 75 studies related to differential expression of circulating miRNAs in GC patients and provide novel view on various heterogenic aspects of the existing data and summarize the methodological differences. Finally, we highlight several important aspects crucial to improve the future translational and clinical research in the field.

miR-27a in serum acts as biomarker for prostate cancer detection and promotes cell proliferation by targeting Sprouty2

Prostate cancer (PCa) exhibits a high incidence among men, but there is no effective and non-invasive biomarker for the diagnosis of PCa, and the pathogenesis of PCa remains unclear. The present study identified that miR-27a was significantly overexpressed in the tumor tissues and sera of patients with PCa. In addition, high serum levels of miR-27a were correlated with poor survival in patients with PCa. Receiver-operating characteristic curves analysis demonstrated that the serum levels of miR-27a exhibited a high area under the curve value. Furthermore, miR-27a mimics or inhibitors significantly promoted or repressed the proliferation of PCa cells, respectively. In addition, it was identified that the expression of Sprouty2 (SPRY2) was inversely correlated with the expression of miR-27a in PCa tissues. The knockdown or overexpression of SPRY2 promoted or suppressed the proliferation of PCa cells, respectively, and the overexpression of SPRY2 inhibited the increased proliferation and cell cycle distribution of PCa cells mediated by miR-27a mimics. Taken together, these data indicated that the serum levels of miR-27a may be a novel and non-invasive biomarker for the diagnosis and prognosis of patients with PCa, and miR-27a/SPRY2 may be a therapeutic target for the treatment of PCa.

MiR-139-5p suppresses osteosarcoma cell growth and invasion through regulating DNMT1

BACKGROUND

Accumulating evidence has suggested the crucial roles of differentially expressed miRNAs in osteosarcoma progression. MiR-139-5p was decreased in various cancers. However, the role of miR-139-5p in the development of osteosarcoma and the underlying mechanism remain to be addressed.

METHODS

MiR-139-5p and DNA methyltransferase-1 (DNMT1) mRNA expressions in osteosarcoma tissues and cells were detected by qRT-PCR and western blot analysis. The effects of miR-139-5p and DNMT1 on osteosarcoma cell migration, invasion and epithelial-mesenchymal transition (EMT) were investigated through cell migration and invasion assays, and western blot analysis. The relationship between miR-139-5p and DNMT1was explored using luciferase reporter analysis and western blot. A xenograft tumor model was employed to verify the effects of miR-139-5p on osteosarcoma.

RESULTS

We found that miR-139-5p was strikingly decreased in osteosarcoma tissues and cell lines. MiR-139-5p over-expression suppressed osteosarcoma cell growth, migration and invasion, while loss of miR-139-5p promoted osteosarcoma cell proliferation, migration and invasion. Following, we characterized that DNMT1 was a direct target of miR-139-5p that interacted with the 3'-untranslated region of DNMT1. MiR-139-5p regulated a down-regulation in DNMT1 protein expression levels. We also found that DNMT1 expression was increased and negatively correlated with miR-139-5p expression in osteosarcoma tissues clinically. Xenograft tumor analysis suggested that miR-139-5p over-expression reduced tumor growth in osteosarcoma in vivo through decreasing DNMT1 expressions.

CONCLUSION

MiR-139-5p suppressed the osteosarcoma progression by reducing DNMT1, supplying new insight into the molecular mechanism uncovering osteosarcoma growth.

Non-Coding RNAs and Resistance to Anticancer Drugs in Gastrointestinal Tumors

Non-coding RNAs are important regulators of gene expression and transcription. It is well established that impaired non-coding RNA expression especially the one of long non-coding RNAs and microRNAs is involved in a number of pathological conditions including cancer. Non-coding RNAs are responsible for the development of resistance to anticancer treatments as they regulate drug resistance-related genes, affect intracellular drug concentrations, induce alternative signaling pathways, alter drug efficiency via blocking cell cycle regulation, and DNA damage response. Furthermore, they can prevent therapeutic-induced cell death and promote epithelial-mesenchymal transition (EMT) and elicit non-cell autonomous mechanisms of resistance. In this review, we summarize the role of non-coding RNAs for different mechanisms resulting in drug resistance (e.g., drug transport, drug metabolism, cell cycle regulation, regulation of apoptotic pathways, cancer stem cells, and EMT) in the context of gastrointestinal cancers.

Effects of miRNA-130a on the proliferation and apoptosis of glioma cell lines

Regulatory ability of micro-ribose nucleic acid-130a (miRNA-130a) in the proliferation and invasive growth of human brain glioma cells and its mechanism were investigated. RT-qPCR was used to analyze expression of miRNA-130a in U-87MG glioma specimens; lipidosome was used to mediate miRNA-130a mimic transfecting glioma cells and the expression of miRNA-130a was detected by using RT-qPCR after transfection; methyl thiazolyl tetrazolium (MTT) assay and flow cytometry (FCM) were adopted to evaluate the changes in biological characteristics of cell growth and proliferation; the migration and invasion abilities of tumor cells were measured through scratch assay and Transwell in vitro cell migration assay. In miRNA-130a mimic-transfected U-87MG cells, RT-qPCR showed that the expression of miRNA-130a was upregulated; MTT assay and FCM revealed that the cell growth was strengthened; scratch assay and Transwell in vitro cell migration assay verified that the migration and invasion abilities of cells were enhanced. In conclusion, the high expression of miRNA-130a can promote growth and invasion, indicating that miRNA-130a can be considered as a candidate target of gene therapy for glioma.

Tumor-derived exosomes promote tumor self-seeding in hepatocellular carcinoma by transferring miRNA-25-5p to enhance cell motility

Tumor self-seeding occurs when circulating malignant cells reinfiltrate the original tumor. The process may breed more aggressive tumor cells, which may contribute to cancer progression. In this study, we observed tumor self-seeding in mouse xenograft models of hepatocellular carcinoma (HCC) for the first time. We confirmed that circulating tumor cell uptake of tumor-derived exosomes, which are increasingly recognized as key instigators of cancer progression by facilitating cell-cell communication, promoted tumor self-seeding by enhancing the invasive and migration capability of recipient HCC cells. Horizontal transfer of exosomal microRNA-25-5p to anoikis-resistant HCC cells significantly enhanced their migratory and invasive abilities, whereas inhibiting microRNA-25-5p alleviated these effects. Our experiments delineate an exosome-based novel pathway employed by functional microRNA from the original tumor cells that can influence the biological fate of circulating tumor cells.

Downregulation of miR-491-5p promotes gastric cancer metastasis by regulating SNAIL and FGFR4

Gastric cancer (GC) is among the most fatal cancers in China. MicroRNAs (miRNAs) are versatile regulators during GC development and progression. miR‐491‐5p has been demonstrated to act as a tumor suppressor in several types of cancer. However, the role of miR‐491‐5p in GC metastasis remains unknown. Here, we found that miR‐491‐5p was significantly decreased in GC tissues compared with adjacent non‐cancerous tissues, and low miR‐491‐5p level was associated with large tumor size. Overexpression of miR‐491‐5p significantly suppressed GC cell epithelial‐to‐mesenchymal transition (EMT) and tumor metastasis in vitro and in vivo. Mechanistically, SNAIL was identified as a direct target of miR‐491‐5p. The silencing of SNAIL phenocopied the tumor suppressive function of miR‐491‐5p, whereas re‐expression of SNAIL in GC cells rescued the EMT markers and cell migratory ability that were inhibited by miR‐491‐5p. In addition, miR‐491‐5p inhibited FGFR4 indirectly. Inhibition of FGFR4 also decreased the SNAIL level and impaired EMT and cell migration. Taken together, these findings indicate that downregulation of miR‐491‐5p promoted GC metastasis by inducing EMT via regulation of SNAIL and FGFR4.