Crosstalk between prognostic long noncoding RNAs and messenger RNAs as transcriptional hallmarks in gastric cancer

Long noncoding RNA TCONS_00026334 is involved in suppressing the progression of colorectal cancer by regulating miR-548n/TP53INP1 signaling pathway

Recently, long noncoding RNAs (lncRNAs) were recognized as significant therapeutic targets in tumors. Our previous microarray analysis showed that lncRNA TCONS_000026334 expression was reduced in metastatic colorectal cancer (CRC) tissues. The objective of this study was to research the biological functions of TCONS_000026334 and the potential mechanism during the development of CRC. TCONS_00026334 transcription levels were detected in CRC tissues from 86 patients and different CRC cell lines. The clinical prognosis factors related to TCONS_00026334 expression were then analyzed. TCONS_000026334 was overexpressed from plasmid pcDNA3.1‐TCONS_ 000026334 or knocked down using a small interfering RNA (siRNA). Furthermore, bioinformatics approach and luciferase reporter gene assays were utilized to search for candidate miRNAs of TCONS_00026334 and identify the downstream target genes. The results indicated that TCONS_00026334 expression in 86 CRC tissues was markedly lower than that in non‐cancerous tissues. The aberrant expression of TCONS_00026334 correlated negatively with larger tumor size, distant metastasis, serological carcinoembryonic antigen level, and unfavorable survival of patients with CRC. TCONS_00026334 overexpression could inhibit the aggressive phenotypes of CRC in vitro and in vivo. Conversely, TCONS_00026334 silencing accelerated CRC cell proliferation and invasion. We then verified that TCONS_00026334 upregulated the expression level of TP53INP1, a target gene of miR‐548n, via direct binding to miR‐548n as a competing endogenous RNA. Taken together, our study showed that TCONS_00026334 acts as an anti‐tumor and anti‐metastatic gene by regulating the miR548n/TP53INP1 axis in the development of CRC.

An Innovative Prognostic Model Based on Four Genes in Asian Patient with Gastric Cancer

Purpose

Gastric cancer (GC) has substantial biological differences between Asian and non-Asian populations, which makes it difficult to have a unified predictive measure for all people. We aimed to identify novel prognostic biomarkers to help predict the prognosis of Asian GC patients.

Materials and Methods

We investigated the differential gene expression between GC and normal tissues of GSE66229. Univariate, multivariate and Lasso Cox regression analyses were conducted to establish a four-gene-related prognostic model based on the risk score. The risk score was based on a linear combination of the expression levels of individual genes multiplied by their multivariate Cox regression coefficients. Validation of the prognostic model was conducted using The Cancer Genome Atlas (TCGA) database. A nomogram containing clinical characteristics and the prognostic model was established to predict the prognosis of Asian GC patients.

Results

Four genes (RBPMS2, RGN, PLEKHS1, and CT83) were selected to establish the prognostic model, and it was validated in the TCGA Asian cohort. Receiver operating characteristic analysis confirmed the sensitivity and specificity of the prognostic model. Based on the prognostic model, a nomogram containing clinical characteristics and the prognostic model was established, and Harrell’s concordance index of the nomogram for evaluating the overall survival significantly higher than the model only focuses on the pathologic stage (0.74 vs. 0.64, p < 0.001).

Conclusion

The four-gene-related prognostic model and the nomogram based on it are reliable tools for predicting the overall survival of Asian GC patients.

Transcriptome hallmarks in Helicobacter pylori infection influence gastric cancer and MALT lymphoma

Aim: Altered long noncoding RNA (lncRNA) and mRNA is vital in the progression from Helicobacter pylori (H. pylori, HP) infection to gastric cancer (GC) and mucosa-associated lymphoid tissue (MALT) lymphoma. Materials & methods: Five independent Gene Expression Omnibus datasets (GSE5081, GSE84433, GSE15459, GSE66229 and GSE25638) were included in our study. Results: Differentially expressed lncRNAs and mRNAs in both H. pylori-positive gastritis and GC tissues were identified. Using two GC cohorts, the H. pylori-related mRNA DYNC1I1 and MMP7 were independent predictors of overall survival. Moreover, the expressions of lncRNA GHRLOS and 44 mRNAs were significantly changed in gastric MALT lymphoma patients. Conclusion: The lncRNA/mRNA response to H. pylori infection in gastritis and GC influence the outcome of GC and progression of MALT lymphoma.

Long non-coding RNA MBNL1-AS1 regulates proliferation, migration, and invasion of cancer stem cells in colon cancer by interacting with MYL9 via sponging microRNA-412-3p

BACKGROUND/AIMS

Colon cancer is a common cancer that is a threat to human health. Some long non-coding RNAs (lncRNAs) have been observed to exert roles in colon cancer. Here, the current study is aimed to explore the potential mechanism of lncRNA MBNL1 antisense RNA 1 (MBNL1-AS1) in progression of colon cancer and the associated mechanisms.

METHODS

Microarray analysis was performed to screen differentially expressed lncRNA and genes associated with colon cancer and its potential mechanism. The functional role of MBNL1-AS1 in colon cancer was analyzed, followed identification of the interaction among MBNL1-AS1, microRNA-412-3p (miR-412-3p), and MYL9. Subsequently, CSC viability, migration, invasion, and apoptosis were detected though a series of in vitro experiments. At last, in vivo experiments were performed to assess tumor formation of colon CSCs.

RESULTS

MBNL1-AS1 and MYL9 were poorly expressed in colon cancer. MBNL1-AS1 could competitively bind to miR-412-3p so as to promote MYL9 expression. Enhancement of MBNL1-AS1 or inhibition of miR-412-3p was shown to decrease CSC proliferation, migration, and invasion but promote apoptosis. Moreover, MBNL1-AS1 reversed the CSC-like properties as well as xenograft tumor formation in vivo induced by miR-412-3p.

CONCLUSION

Collectively, the present study suggests an inhibitory role of MBNL1-AS1 in colon cancer by upregulating miR-412-3p-targeted MYL9. Thus, this study provides an enhanced understanding of MBNL1-AS1 along with miR-412-3p and MYL9 as therapeutic targets for colon cancer.

Down expression of lnc-BMP1-1 decreases that of Caveolin-1 is associated with the lung cancer susceptibility and cigarette smoking history

Lnc-BMP1-1 is a lncRNA transcribed from SFTPC (surfactant associated protein C), a lung tissue specific gene encoding pulmonary-associated surfactant protein C (SPC) that is solely secreted by alveolar typeⅡ epithelial cells, among which the ones with SFTPC+ might be transformed into lung adenocarcinoma cells. Caveolin-1 (Cav-1) is a candidate tumor suppressor gene and is vital for coping with oxidative stress induced by cigarette smoke. When comparing lung cancer tissues with their adjacent normal tissues, the expression of lnc-BMP1-1 were decreased, especially in patients with cigarette smoking history (P=0.027), and positively associated with the expression of Cav-1 (P<0.001). When comparing to A549 cells transfected with empty vector (A549-NC cells), the expression level of Cav-1 in A549 cells with over-expressed lnc-BMP1-1 (A549-BMP cells) was increased along with the decreased level of HDAC2 protein. The drug sensitivity of A549-BMP cells to Doxorubicin hydrochloride (DOX) was increased; the growth and migration capability of A549-BMP cells were inhibited along with the decreased protein level of Bcl-2 and DNMT3a; the growth of tumor in nude mice injected with A549-BMP cells were inhibited, too. Furthermore, the lnc-BMP1-1 and Cav-1 expression was also down-regulated in the human bronchial epithelial (16HBE) cells treated with cigarette smoke extract (CSE).

LINC01018 confers a novel tumor suppressor role in hepatocellular carcinoma through sponging microRNA-182-5p

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality. Emerging evidence has demonstrated that some long noncoding RNAs (lncRNAs) are involved in the development and progression of HCC. Herein, the current study aimed to explore the potential mechanism of LINC01018 in regulating the progression of HCC. Initially, the expression of LINC01018, microRNA-182-5p (miR-182-5p), and forkhead box protein O1 (FOXO1) was quantified in 72 paired HCC and adjacent normal tissue samples as well as HCC cells, followed by identification of the interaction among them. To define the contributory role of LINC01018 in the progression of HCC, the expression of LINC01018, miR-182-5p, or FOXO1 was altered in HCC cells, followed by evaluation of cell proliferation, cell cycle distribution, and cell apoptosis. Finally, in vivo tests were performed to further verify the role of LINC01018 in HCC. It was observed that LINC01018 and FOXO1 were poorly expressed but miR-182-5p was highly expressed in HCC tissues and cells. The upregulation of LINC01018 was shown to decrease proliferation while promoting apoptosis of HCC cells. LINC01018 acted as a sponge of miR-182-5p, which targeted FOXO1. Last, mice injected with Hep3B overexpressing FOXO1 displayed suppressed xenograft tumor formation. Collectively, overexpression of LINC01018 represses proliferation and promotes apoptosis of HCC cells via upregulation of FOXO1 by sponging miR-182-5p, which highlights overexpression of LINC01018 as a candidate suppressor of HCC.NEW & NOTEWORTHY This study provides evidence for understanding the molecular mechanism involved in the progression of hepatocellular carcinoma and identifies a novel network of LINC01018/miR-182-5p/FOXO1. We also conducted in vivo experiments in nude mice to validate the anti-tumor effect of LINC01018.

Identification of miR-200c and miR141-Mediated lncRNA-mRNA Crosstalks in Muscle-Invasive Bladder Cancer Subtypes

Basal and luminal subtypes of muscle-invasive bladder cancer (MIBC) have distinct molecular profiles and heterogeneous clinical behaviors. The interactions between mRNAs and lncRNAs, which might be regulated by miRNAs, have crucial roles in many cancers. However, the miRNA-dependent crosstalk between lncRNA and mRNA in specific MIBC subtypes still remains unclear. In this study, we first classified MIBC into two conservative subtypes using miRNA, mRNA and lncRNA expression data derived from The Cancer Genome Atlas. Then we investigated subtype-related biological pathways and evaluated the subtype classification performance using Decision Trees, Random Forest and eXtreme Gradient Boosting (XGBoost). At last, we explored potential miRNA-mediated lncRNA-mRNA crosstalks based on co-expression analysis. Our results show that: (1) the luminal subtype is primarily characterized by upregulation of metabolism-related pathways while the basal subtype is predominantly characterized by upregulation of epithelial-mesenchymal transition, metastasis, and immune system process-related pathways; (2) the XGBoost prediction model is consistently robust for classification of the molecular subtypes of MIBC across four datasets (The area under the ROC curve > 0.9); (3) the expression levels of the molecules in the miR-200c and miR141-mediated lncRNA-mRNA crosstalks differ considerably between the two subtypes and have close relationships with the prognosis of MIBC. The miR-200c and miR-141-dependent mRNA-lncRNA crosstalks might be of great significance in tumorigenesis and tumor progression and may serve as the novel prognostic predictors and classification markers of MIBC subtypes.

Role of microRNAs and Exosomes in Helicobacter pylori and Epstein-Barr Virus Associated Gastric Cancers

Emerging evidence suggests that chronic inflammation caused by pathogen infection is connected to the development of various types of cancer. It is estimated that up to 20% of all cancer deaths is linked to infections and inflammation. In gastric cancer, such triggers can be infection of the gastric epithelium by either Helicobacter pylori (H. pylori), a bacterium present in half of the world population; or by Epstein-Barr virus (EBV), a double-stranded DNA virus which has recently been associated with gastric cancer. Both agents can establish lifelong inflammation by evolving to escape immune surveillance and, under certain conditions, contribute to the development of gastric cancer. Non-coding RNAs, mainly microRNAs (miRNAs), influence the host innate and adaptive immune responses, though long non-coding RNAs and viral miRNAs also alter these processes. Reports suggest that chronic infection results in altered expression of host miRNAs. In turn, dysregulated miRNAs modulate the host inflammatory immune response, favoring bacterial survival and persistence within the gastric mucosa. Given the established roles of miRNAs in tumorigenesis and innate immunity, they may serve as an important link between H. pylori- and EBV-associated inflammation and carcinogenesis. Example of this is up-regulation of miR-155 in H. pylori and EBV infection. The tumor environment contains a variety of cells that need to communicate with each other. Extracellular vesicles, especially exosomes, allow these cells to deliver certain type of information to other cells promoting cancer growth and metastasis. Exosomes have been shown to deliver not only various types of genetic information, mainly miRNAs, but also cytotoxin-associated gene A (CagA), a major H. pylori virulence factor. In addition, a growing body of evidence demonstrates that exosomes contain genetic material of viruses and viral miRNAs and proteins such as EBV latent membrane protein 1 (LMP1) which are delivered into recipient cells. In this review, we focus on the dysregulated H. pylori- and EBV-associated miRNAs while trying to unveil possible causal mechanisms. Moreover, we discuss the role of exosomes as vehicles for miRNA delivery in H. pylori- and EBV-related carcinogenesis.