LINC00978 predicts poor prognosis in breast cancer patients

Biological Roles and Pathogenic Mechanisms of LncRNA MIR4435-2HG in Cancer: A Comprehensive Review

The long non-coding RNA MIR4435-2HG has been confirmed to play a crucial regulatory role in various types of tumors. As a novel type of non-coding RNA, MIR4435-2HG plays a key role in regulating the expression of tumor-related genes, interfering with cellular signaling pathways, and affecting tumor immune evasion. Its unique structure allows it to regulate the expression of various tumor-related genes through different pathways, participating in the regulation of tumor signaling pathways, such as regulating the expression of oncogenes and tumor suppressor genes, influencing the biological behaviors of proliferation, metastasis, and apoptosis in tumors. Numerous studies have found a high expression of MIR4435-2HG in various tumor tissues, closely related to the clinical pathological characteristics of tumors, such as staging, lymph node metastasis and prognosis. Some studies have discovered that MIR4435-2HG can regulate the sensitivity of tumor cells to chemotherapy drugs, affecting tumor cell drug resistance. This provides new insights into overcoming tumor drug resistance by regulating MIR4435-2HG. Therefore, studying its molecular mechanisms, expression regulation, and its relationship with the clinical features of tumors is of great significance for revealing the mechanisms of tumor occurrence and developing new therapeutic targets.

Regulation of main ncRNAs by polyphenols: A novel anticancer therapeutic approach

BACKGROUND

Plant polyphenols have shown promising applications in oncotherapy. Increasing evidence reveals that polyphenols possess the antitumor potential for multiple cancers. Non-coding RNAs (ncRNAs), mainly including small ncRNAs (microRNA) and long ncRNAs (lncRNAs), play critical roles in cancer initiation and progression.

PURPOSE

To establish the modulation of ncRNAs by polyphenols as a novel and promising approach in anticancer treatment.

STUDY DESIGN

The present research employed ncRNA, miRNA, lncRNA, and regulatory mechanism as keywords to retrieve the literature from PubMed, Web of Science, Science direct, and Google Scholar, in a 20-year period from 2003 to 2023. This study critically reviewed the current literature and presented the regulation of prominent ncRNAs by polyphenols. A comprehensive total of 169 papers were retrieved on polyphenols and their related ncRNAs in cancers.

RESULTS

NcRNAs, mainly including miRNA and lncRNA, play critical roles in cancer initiation and progression, which are potential modulatory targets of bioactive polyphenols, such as resveratrol, genistein, curcumin, EGCG, quercetin, in cancer management. The mechanism involved in polyphenol-mediated ncRNA regulation includes epigenetic and transcriptional modification, and post-transcriptional processing.

CONCLUSION

Regulatory ncRNAs are potential therapeutic targets of bioactive polyphenols, and these phytochemicals could modulate the level of these ncRNAs directly and indirectly. A better comprehension of the ncRNA regulation by polyphenols in cancers, their functional outcomes on tumor pathophysiology and regulatory molecular mechanisms, may be helpful to develop effective strategies to fight the devastating disease.

An overview of natural products that modulate the expression of non-coding RNAs involved in oxidative stress and inflammation-associated disorders

Oxidative stress is a state in which oxidants are produced in excess in the body's tissues and cells, resulting in a biological imbalance amid the generation of reactive oxygen and nitrogen species (RONS) from redox reactions. In case of insufficient antioxidants to balance, the immune system triggers signaling cascades to mount inflammatory responses. Oxidative stress can have deleterious effects on major macromolecules such as lipids, proteins, and nucleic acids, hence, Oxidative stress and inflammation are among the multiple factors contributing to the etiology of several disorders such as diabetes, cancers, and cardiovascular diseases. Non-coding RNAs (ncRNAs) which were once referred to as dark matter have been found to function as key regulators of gene expression through different mechanisms. They have dynamic roles in the onset and development of inflammatory and oxidative stress-related diseases, therefore, are potential targets for the control of those diseases. One way of controlling those diseases is through the use of natural products, a rich source of antioxidants that have drawn attention with several studies showing their involvement in combating chronic diseases given their enormous gains, low side effects, and toxicity. In this review, we highlighted the natural products that have been reported to target ncRNAs as mediators of their biological effects on oxidative stress and several inflammation-associated disorders. Those natural products include Baicalein, Tanshinone IIA, Geniposide, Carvacrol/Thymol, Triptolide, Oleacein, Curcumin, Resveratrol, Solarmargine, Allicin, aqueous extract or pulp of Açai, Quercetin, and Genistein. We also draw attention to some other compounds including Zanthoxylum bungeanum, Canna genus rhizome, Fuzi-ganjiang herb pair, Aronia melanocarpa, Peppermint, and Gingerol that are effective against oxidative stress and inflammation-related disorders, however, have no known effect on ncRNAs. Lastly, we touched on the many ncRNAs that were found to play a role in oxidative stress and inflammation-related disorders but have not yet been investigated as targets of a natural product. Shedding more light into these two last points of shadow will be of great interest in the valorization of natural compounds in the control and therapy of oxidative stress- and inflammation-associated disorders.

Long Noncoding RNA MIR4435-2HG Suppresses Colorectal Cancer Initiation and Progression By Reprogramming Neutrophils

MIR4435-2HG, also known as LINC00978, has previously been described as an oncogenic long noncoding RNA (lncRNA). However, we show here that Mir4435-2hg depletion promoted colorectal tumorigenesis and progression in in vivo models of colitis-associated colorectal cancer, spontaneous intestinal adenomatous polyposis, and subcutaneous tumors. Alteration of MIR4435-2HG in colorectal cancer cells did not change the potential for cell proliferation, migration, or invasion in vitro. RNAscope assays showed that most MIR4435-2HG was located in the tumor stroma, which caused high expression of MIR4435-2HG in colorectal cancer tumor tissue. Transcriptome analysis of colorectal cancer tissues from wild-type and Mir4435-2hg-deficient mice revealed Mir4435-2hg as a tumor suppressor gene that regulated the immune microenvironment. Loss of Mir4435-2hg led to a decline in neutrophils and elevation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC). In tissue-specific Mir4435-2hg knockout mice, we confirmed that Mir4435-2hg depletion in neutrophils, but not in intestinal epithelial cells, promoted colorectal cancer progression. Mechanistically, Mir4435-2hg depletion enhanced the immunosuppressive ability of PMN-MDSCs by disturbing their fatty acid metabolism. These findings suggest that MIR4435-2HG is a tumor-suppressing lncRNA whose deficiency could increase tumor-infiltrating PMN-MDSCs and enhance the immunosuppressive potential of PMN-MDSCs to promote colorectal cancer development. This provides a theoretical basis for further illustrating the pathogenesis of colorectal cancer and a potential antitumor immunotherapy target.

MIR4435-2HG Is a Potential Pan-Cancer Biomarker for Diagnosis and Prognosis

The lncRNA MIR4435-2 host gene (MIR4435-2HG) is located on human chromosome 2q13, and its expression is up-regulated in 18 tumors. MIR4435-2HG participates in 6 signaling pathways to promote tumorigenesis, including the TGF-β signaling pathway, Wnt/β-catenin signaling pathway, MDM2/p53 signaling pathway, PI3K/AKT signaling pathway, Hippo signaling pathway, and MAPK/ERK signaling pathway. MIR4435-2HG competitively binds with 20 miRNAs to form a complex ceRNA network, thereby regulating the expression of downstream target genes. The high expression of MIR4435-2HG is also closely related to the clinicopathological characteristics and poor prognosis of a variety of tumors. Also, the high expression of MIR4435-2HG in peripheral blood or serum has the value of predicting the risk of 9 tumors. In addition, MIR4435-2HG participates in the mechanism of action of three cancer drugs, including resveratrol for the treatment of lung cancer, cisplatin for non-small cell lung cancer and colon cancer, and carboplatin for triple-negative breast cancer. This article systematically summarizes the diagnostic and prognostic value of MIR4435-2HG in a variety of tumors and outlines the ceRNA network and signaling pathways related to MIR4435-2HG, which will provide potential directions for future MIR4435-2HG research.

LncRNA00978 contributes to growth and metastasis of hepatocellular carcinoma cells via mediating microRNA-125b-5p/SOX12 pathway

As a malignant tumor, HCC (hepatocellular carcinoma) is featured by a high recurrence rate with a poor prognosis. Increasing evidence supports an important role of lincRNAs in HCC. Here, the purpose of the study was to explore the function of LINC00978 (long non-coding RNA00978) in HCC and the underlying mechanisms. LINC00978 expression and its association with the progression of HCC were analyzed using HCC TCGA datasets. LINC00978 expression in tissues was measured using real-time PCR. Then, we knocked down LINC00978 in HCC cells to explore its effect on cellular invasion, proliferation, and migration. Finally, we investigated the potential molecular mechanism of LINC00978 by dual Luciferase reporter assay, FISH (fluorescence in situ hybridization) and RIP (RNA immunoprecipitation). LINC00978 expression was remarkably increased in HCC. A high level of LINC00978 was associated with poor prognosis of HCC. Additionally, LINC00978 silencing could repress the growth and metastasis of HCC cells. Mechanistically, it was revealed that LINC00978 could sponge microRNA-125b-5p and identified SOX12 (SRY-Box Transcription Factor 12) as a direct target gene of microRNA-125b-5p. More importantly, the suppressed effect of LINC00978 silencing on the metastasis and growth of HCC cells could be rescued by miR-125b-5p inhibition and overexpressed SOX12. LINC00978/microRNA-125b-5p/SOX12 axis promoted liver cancer migration, invasion, and proliferation, which could be used as a possible therapeutic target for the treatment of hepatocellular carcinoma.

A seven-lncRNA signature for predicting prognosis in breast carcinoma

Background

Long non-coding RNAs (lncRNAs) play an important part in tumorigenesis and cancer metastasis and can serve as a potential biosignature for cancer prognosis. However, the use of lncRNA signatures to predict survival in breast carcinoma is yet unreported.

Methods

The lncRNA expression profiles and homologous clinical data of 913 breast carcinoma samples from the Cancer Genome Atlas (TCGA), were analyzed to obtain 2,547 differentially expressed lncRNAs. Univariate Cox proportional risk regression was applied to both the training and testing datasets to screen the common prognostic lncRNAs. Potential prognostic LncRNAs were screened by multivariate Cox proportional risk regression in the training data set of the selected LncRNAs.

Results

Seven lncRNAs (LINC02037, MAPT-AS1, RP1-37C10.3, RP11-344E13.4, RP11-454P21.1, RP11-616M22.1, SPACA6P-AS) were prominently associated with overall survival. Kaplan-Meier analysis and receiver operating characteristic (ROC) curves indicated that these indicators were sensitive and specific for survival prediction. The areas under the ROC curve of the seven-lncRNA signature in predicting 3- and 5-year survival rates were 0.771 and 0.780 respectively in the combined cohort. Furthermore, enrichment analysis revealed that these seven lncRNAs might participate multiple pathways related to tumorigenesis and prognosis.

Conclusions

The proposed seven-lncRNA signature could serve as a latent prognostic biomarker for survival prediction in patients with breast carcinoma.

Competing Endogenous RNA Network in Non-Keloid-Prone Individuals During Wound Healing

ABSTRACT

To study the interaction between differentially expressed long non-coding RNAs (lncRNAs), microRNAs, and messenger RNAs during wound healing in normal individuals. The GSE113621 dataset was downloaded from gene expression matrix, specimens regarding non-keloid-prone individuals were selected, including items before and 6 weeks after injury. A Pearson correlation coefficient of > 0.95 was selected as the index to screen targeting relationships among different RNAs. Cytoscape was used to construct a network diagram. The expression of 2547 lncRNAs was changed during the wound healing process-1479 were upregulated and 1068 were downregulated. After analyzing competitive endogenous RNA network, 4 upregulated (MEG8, MEG3, MIR181A1HG, MIR4435-2HG) lncRNAs were found expressed during wound healing. MEG8/MEG3 may regulate fibroblast proliferation, differentiation, and apoptosis through hsa-miR-296-3p/miR-6763-5p. In-depth mining of gene expression matrix data indicated that lncRNAs and a competitive endogenous RNA regulatory network participate in the wound healing process, possibly providing novel intervention targets and treatment options for delayed wound healing.

A Pan-Cancer Analysis of Transcriptome and Survival Reveals Prognostic Differentially Expressed LncRNAs and Predicts Novel Drugs for Glioblastoma Multiforme Therapy

Numerous studies have identified various prognostic long non-coding RNAs (LncRNAs) in a specific cancer type, but a comprehensive pan-cancer analysis for prediction of LncRNAs that may serve as prognostic biomarkers is of great significance to be performed. Glioblastoma multiforme (GBM) is the most common and aggressive malignant adult primary brain tumor. There is an urgent need to identify novel therapies for GBM due to its poor prognosis and universal recurrence. Using available LncRNA expression data of 12 cancer types and survival data of 30 cancer types from online databases, we identified 48 differentially expressed LncRNAs in cancers as potential pan-cancer prognostic biomarkers. Two candidate LncRNAs were selected for validation in GBM. By the expression detection in GBM cell lines and survival analysis in GBM patients, we demonstrated the reliability of the list of pan-cancer prognostic LncRNAs obtained above. By constructing LncRNA-mRNA-drug network in GBM, we predicted novel drug-target interactions for GBM correlated LncRNA. This analysis has revealed common prognostic LncRNAs among cancers, which may provide insights into cancer pathogenesis and novel drug target in GBM.

Inhibition of MIR4435-2HG on Invasion, Migration, and EMT of Gastric Carcinoma Cells by Mediating MiR-138-5p/Sox4 Axis

Background

The previous investigations have identified that long non-coding RNA (lncRNAs) act as crucial regulators in gastric carcinoma. However, the function of lncRNA MIR4435-2HG in the modulation of gastric carcinoma remains elusive. Here, we aimed to explore the role of MIR4435-2HG in gastric carcinoma.

Method

The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were applied to select the differently expressed lncRNAs in gastric carcinoma. The qRT-PCR was applied to analyze MIR4435-2HG expression in carcinoma tissues and cell lines. The effect of MIR4435-2HG on proliferation, invasion, migration, and apoptosis of gastric carcinoma cells was detected by Cell Counting Kit-8 (CCK-8) assays, transwell assays, and flow cytometry in vitro. A subcutaneous tumor model was constructed to examine the tumor growth of gastric carcinoma cells after knocking out MIR4435-2HG. RNA immunoprecipitation and luciferase reporting assays were applied to evaluate the interaction of MIR4435-2HG, miR-138-5p, and Sox4.

Results

The bioinformatics analysis based on TCGA and GEO databases indicated that MIR4435-2HG was obviously elevated in gastric carcinoma samples. The qRT-PCR analysis revealed that MIR4435-2HG was upregulated in clinical gastric carcinoma tissues and cells. The high expression of MIR4435-2HG is associated with the poor survival rate of patients. The knockout of MIR4435-2HG could repress the proliferation, invasion, migration, and epithelial–mesenchymal transition (EMT) and accelerate the apoptosis of gastric carcinoma cells. Moreover, the deletion of MIR4435-2HG was able to attenuate the tumor growth in vivo. Mechanically, we identified that MIR4435-2HG enhanced Sox4 expression by directly interacting with miR-138-5p as a competitive endogenous RNA (ceRNA) in gastric carcinoma cells, in which Sox4 was targeted by miR-138-5p.

Conclusion

MIR4435-2HG is elevated in gastric carcinoma cells and contributes to the growth, metastasis, and EMT of gastric carcinoma cells by targeting miR-138-5p/Sox4 axis. MIR4435-2HG may be applied as a potential therapeutic target in gastric carcinoma.

Aberrant expression of lncRNAs SNHG6, TRPM2-AS1, MIR4435-2HG, and hypomethylation of TRPM2-AS1 promoter in colorectal cancer

Accumulating evidence has indicated that deregulation of lncRNAs plays essential roles in colorectal cancer (CRC) carcinogenesis. The goal of this study was to analyze the expression of lncRNAs in colorectal cancer and their association with clinicopathological variables. Bioinformatics analysis of published CRC microarray data was performed to identify the important lncRNAs. The expression levels of candidate genes were assessed in the human colon cancer/normal cell lines, CRC, adenomatous colorectal polyps, and their marginal tissues by qRT-PCR. Moreover, the methylation status of the TRPM2-AS1 promoter was studied using qMSP assay. Furthermore, we investigated the molecular mechanisms of these lncRNAs in CRC progression using in silico analysis. Microarray analysis revealed that lncRNAs SNHG6, MIR4435-2HG, and TRPM2-AS1 were upregulated in CRC. These results were validated in colon cell lines. Moreover, qRT-PCR showed that the expression levels of SNHG6 and TRPM2-AS1 were upregulated in the colorectal tumor tissues compared with their paired tissues. Nonetheless, there was no significant increase in MIR4435-2HG expression in CRC samples. Furthermore, we observed a significant hypomethylation of TRPM2-AS1 promoter and its activation in CRC tissues. By in silico analysis, we found that the lncRNAs upregulation could promote proliferation and drug resistance of colorectal cancer cells via miRNAs sponging and modulation of their targets expression. In conclusion, based on our results upregulation of SNHG6 and TRPM2-AS1, and hypomethylation of TRPM2-AS1 promoter might be considered as potential diagnostic biomarkers for CRC initiation and development.

Long noncoding RNA LINC00978 acts as a potential diagnostic biomarker in patients with colorectal cancer

Colorectal cancer (CRC) as a lethal malignancy has been associated with dysregulation of several genes and pathways. Long noncoding RNAs (lncRNAs) play an important role in gene expression regulation. In the current research, we aim to evaluate the expression of LINC00978 in CRC samples and adjacent tissues. Using Quantitative Real-Time PCR (qRT-PCR) method, we assessed the expression levels of LINC00978 and β-catenin in 70 pairs of CRC and adjacent tissues. Moreover, the association between clinicopathological features and the LINC00978 expression levels was investigated. To assess the diagnostic power of LINC00978 expression in CRC, receiver operating characteristic (ROC) curve was plotted. The relationship between LINC00978 and β-catenin expression levels was evaluated using correlation analysis. A markedly increased level of LINC00978 and β-catenin expression levels was observed in CRC samples compared with adjacent tissues (P < 0.0001). No significant association was detected between LINC00978 expression level and the patient's clinicopathological features. The results of Pearson's correlation coefficient highlighted a positive correlation between LINC00978 and β-catenin expression (r² = 0.4695, P < 0.0001). According to the area under curve (AUC) value, LINC00978 expression differentiates CRC samples from the adjacent tissues (AUC = 0.81, P < 0.0001). The present results suggest that LINC00978 may play a critical role in CRC progression via Wnt pathway. The potential role of LINC00978 as a diagnostic biomarker needs to be further investigated in future studies.

LncRNA AWPPH as a prognostic predictor in human cancers in Chinese population: evidence from meta-analysis

Background: Long non-coding RNA associated with poor prognosis of hepatocellular carcinoma (AWPPH) is dysregulated in a variety of human cancers. However, the prognostic value of AWPPH in various cancers remains unclear.

Methods: Comprehensive literature search was performed in PubMed, Web of Science, CNKI and Wangfang databases, and eligible studies were obtained according to the inclusion and exclusion criteria. The pooled hazard ratios (HRs) and odds ratios (ORs) were applied to assess the clinical value of AWPPH expression for overall survival (OS) and clinicopathological features.

Results: A total of 19 articles including 1699 cancer patients were included in the study. The pooled results demonstrated that evaluated AWPPH expression was positively related to a poorer overall survival of patients with cancers (HR = 1.79, 95%CI: 1.44–2.14, P<0.001). Subgroup analysis revealed that tumor type and sample size affect the predictive value of AWPPH on OS, whereas cut-off value and HR estimation method have no impact on it. In addition, the pooled data also showed that AWPPH was positively linked to advanced TNM stage (OR = 2.50, 95%CI: 1.94–3.22, P<0.001), bigger tumor size (OR = 2.64, 95%CI: 1.47–4.73, P=0.001), macro-vascular invasion (OR = 2.08, 95%CI: 1.04–4.16, P=0.04) and lymph node metastasis (OR = 2.68, 95%CI: 1.82–3.96, P<0.001). Moreover, the results of the trim and fill analysis confirmed the reliability of our finding.

Conclusions: Up-regulation of AWPPH was associated with advanced TNM stage, bigger tumor size, worse lymph node metastasis, macro-vascular invasion and shorter overall survival, suggesting that AWPPH may serve as a biomarker for prognosis and clinicopathological characteristics in human cancers among the Chinese population.

Long non-coding RNA AWPPH enhances malignant phenotypes in nasopharyngeal carcinoma via silencing PTEN through interacting with LSD1 and EZH2

Evidence has emerged identifying long noncoding RNAs (lncRNAs) as important regulators of various cancers including nasopharyngeal carcinoma (NPC). LncRNA AWPPH is an oncogene recently identified in several cancers. However, the underlying role of AWPPH in NPC is still unclear and thus worth exploring. In this study, AWPPH expression was markedly upregulated in NPC cells. Further, loss- and gain-of-function assays indicated that AWPPH facilitates cell proliferation and migration and hinders apoptosis in NPC cells. Moreover, cytoplasmic AWPPH was predicted to share a common RNA-binding protein, IGF2BP1, with LSD1. The interaction between IGF2BP1 and both AWPPH and LSD1 mRNA was verified in NPC cells, and AWPPH stabilized LSD1 mRNA to enhance the expression of LSD1 in NPC through such interactions. Furthermore, nuclear AWPPH repressed PTEN expression through recruiting EZH2 and LSD1 to the PTEN promoter in NPC cells. Final rescue assays demonstrated that silenced PTEN could reverse the suppressive influence of AWPPH depletion on the progression of NPC. Collectively, our study shows that AWPPH inhibits PTEN expression to drive NPC progression through interacting with LSD1 and EZH2, providing potential biomarkers for NPC treatment.

LINC00978 promotes hepatocellular carcinoma carcinogenesis partly via activating the MAPK/ERK pathway

Objective: To study the role of long non-coding RNA (lncRNA) LINC00978 in hepatocellular carcinoma (HCC) carcinogenesis.

Materials and methods: LINC00978 expression level was measured by reverse transcription quantitative real-time PCR (RT-qPCR) in HCC tissues and adjacent healthy liver tissues from 49 HCC patients. MTT assay, colony forming assay, and flow cytometry were performed to evaluate the effects of shRNA-mediated LINC00978 knockdown on HCC cell proliferation, cell cycle progression, and apoptosis in vitro. Xenograft tumor model was performed to determine the effects of LINC00978 knockdown on HCC tumor growth in vivo. Western blot was used to assess the activation of signaling molecules in the apoptosis and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway.

Results: LINC00978 expression was significantly up-regulated in human HCC tissue relative to adjacent normal tissue, and LINC00978 high expression was correlated with poor HCC overall survival. LINC00978 was up-regulated in HCC cell lines. ShRNA-mediated LINC00978 knockdown significantly decreased HCC cell proliferation, and induced HCC cell cycle arrest and apoptosis in vitro. LINC00978 knockdown led to significant decrease in tumor xenograft size in vivo. Western blots revealed LINC00978 inhibition decreased ERK, p38, and c-Jun N-terminal kinase (JNK) phosphorylation in HCC cells.

Conclusions: LINC00978 is highly expressed in human HCC tissue and correlates with poor HCC prognosis. LINC00978 promotes HCC cell proliferation, cell cycle progression, and survival, partially by activating the MAPK/ERK pathway. Our findings partially elucidated the roles of LINC00978 in HCC carcinogenesis, and identified a therapeutic target for HCC.

Downregulation of long non-coding RNA MR4435-2HG suppresses breast cancer progression via the Wnt/β-catenin signaling pathway

Extensive research has contributed to the current understanding of the critical roles played by long non-coding RNAs in various types of cancer. The present study aimed to investigate the function and mechanism of the long non-coding RNA, MIR4435-2HG (also termed LINC00978), in breast cancer growth and metastasis. Using Gene Expression Profiling Interactive Analysis, an online web tool, it was revealed that MIR4435-2HG was upregulated in breast cancer tissue, and its high expression was associated with poor prognosis based on The Cancer Genome Atlas database. MIR4435-2HG knockdown increased cell apoptosis but decreased cell proliferation, migration and invasion. MIR4435-2HG knockdown increased pro-apoptotic protein expression but decreased anti-apoptotic protein expression. In addition, MIR4435-2HG knockdown leads to dysregulation of epithelial-to-mesenchymal transition-associated genes. Furthermore, knockdown of MIR4435-2HG results in inactivation of the Wnt/β-catenin signaling pathway. The results of the present study demonstrate the tumor-promoting role of MIR4435-2HG in breast cancer progression.

Long noncoding RNAs in cancer immunity: a new avenue in drug discovery

The central role of the nonprotein-coding portion of the genome, such as long noncoding (lnc)RNAs is emerging as a hidden player manipulating the immune system in cancer. lncRNAs, in association with their interacting partners, regulate the expression of various immune system genes, which are perturbed during cancer. The tissue-specific expression of lncRNAs and their importance in cellular proliferation, the tumor microenvironment (TME), epithelial-mesenchymal transition (EMT), and modulation of the cells of the innate and adaptive immune system have novel therapeutic implications in establishing lncRNAs as biomarkers and targets to overcome cancer-associated immunosuppression. In this review, we establish and strengthen the link between lncRNAs and cancer immunity.

A long non-coding RNA LINC00461-dependent mechanism underlying breast cancer invasion and migration via the miR-144-3p/KPNA2 axis

Background

The purpose of this study was to explore the regulatory mechanism of the long non-coding RNA (lncRNA) LINC00461 underlying the breast cancer invasion and migration via the miR-144-3p/KPNA2 axis.

Methods

Bioinformatics methods were applied to screen differentially expressed mRNAs, miRNAs and lncRNAs for construction of a competing endogenous RNA (ceRNA) network. LINC00461, KPNA2 and miR-144-3p were identified, and KPNA2 was predicted to be a target of miR-144-3p and significantly correlated with breast cancer prognosis. To make the findings more convincible, we used qRT-PCR to detect the expression levels of LINC00461 and miR-144-3p in breast cancer cells, and conducted western blot to determine KPNA2 protein level. Then, RIP was performed to assess the combination between miR-144-3p and LINC00461 or KPNA2, and dual-luciferase reporter assay was used to validate the targeted relationship between miR-144-3p and KPNA2. Furthermore, Transwell was employed for the examination of cell invasion and migration in breast cancer.

Results

LINC00461 was predicted to regulate KPNA2 through sponging miR-144-3p as revealed by the ceRNA network. Besides, LINC00461 and KPNA2 were found to be remarkably highly-expressed in breast cancer cells, while miR-144-3p was poorly-expressed. Silencing LINC00461 could promote miR-144-3p expression, thus inhibiting cell invasion and migration. In addition, KPNA2 was confirmed to be a direct target of miR-144-3p. Silencing miR-144-3p or overexpressing KPNA2 could reverse the inhibitory effect of LINC00461 silencing on cell invasion and migration in breast cancer.

Conclusion

LINC00461 promoted the expression of KPNA2 by competitively binding to miR-144-3p, thereby promoting the invasion and migration of breast cancer cells.

Fusobacterium nucleatum promotes epithelial-mesenchymal transiton through regulation of the lncRNA MIR4435-2HG/miR-296-5p/Akt2/SNAI1 signaling pathway

Fusobacterium nucleatum, an anaerobic oral opportunistic pathogen associated with periodontitis, has been considered to be associated with the development of oral squamous cell carcinoma (OSCC). However, the initial host molecular alterations induced by F. nucleatum infection which may promote predisposition to malignant transformation through epithelial–mesenchymal transition (EMT) have not yet been clarified. In the present study, we monitored the ability of F. nucleatum to induce EMT‐associated features, and our results showed that F. nucleatum infection promoted cell migration in either noncancerous human immortalized oral epithelial cells (HIOECs) or the two OSCC cell lines SCC‐9 and HSC‐4, but did not accelerate cell proliferation or cell cycle progression. Mesenchymal markers, including N‐cadherin, Vimentin, and SNAI1, were upregulated, while E‐cadherin was decreased and was observed to translocate to the cytoplasm. Furthermore, FadA adhesin and heat‐inactivated F. nucleatum were found to cause a similar effect as the viable bacterial cells. The upregulated lncRNA MIR4435‐2HG identified by the high‐throughput sequencing was demonstrated to negatively regulate the expression of miR‐296‐5p, which was downregulated in F. nucleatum‐infected HIOECs and SCC‐9 cells. The binding of MIR4435‐2HG and miR‐296‐5p was validated via a dual‐luciferase reporter assay. Additionally, knockdown of MIR4435‐2HG with siRNA leads to a decrease in SNAI1 expression, while miR‐296‐5p could further negatively and indirectly regulate SNAI1 expression via Akt2. Therefore, our study demonstrated that F. nucleatum infection could trigger EMT via lncRNA MIR4435‐2HG/miR‐296‐5p/Akt2/SNAI1 signaling pathway, and EMT process may be a probable link between F. nucleatum infection and initiation of oral epithelial carcinomas.

Characterization of long non-coding RNA and messenger RNA profiles in laryngeal cancer by weighted gene co-expression network analysis

Laryngeal cancer (LC) is a malignant tumor in the head and neck region. It was recently elucidated that long non-coding RNAs (lncRNAs) participate in the pathogenesis of LC. However, the detailed mechanism of lncRNA in LC and whether long non-coding RNAs serve as effective biomarkers remains unclear. Ribonucleic acid (RNA) sequence data of LC and 11 patient clinical traits were extracted from The Cancer Genome Atlas (TCGA) database and analyzed by weighted gene co-expression network analysis (WGCNA). A total of 9 co-expression modules were identified. The co-expression Pink module significantly correlated with four clinical traits, including history of smoking, lymph node count, tumor status, and the success of follow-up treatment. Based on the co-expression Pink module, lncRNA-microRNA (miRNA)-messenger RNA (mRNA) and lncRNA-RNA binding protein-mRNA networks were constructed. We found that 8 lncRNAs significantly impacted overall survival (OS) in LC patients. These identified lncRNA and hub gene biomarkers were also validated in multiple LC cells in vitro via qPCR. Taken together, this study provided the framework of co-expression gene modules of LC and identified some important biomarkers in LC development and disease progression.

LINC00978 promotes the progression of hepatocellular carcinoma by regulating EZH2-mediated silencing of p21 and E-cadherin expression

Long non-coding RNAs (lncRNAs) have been suggested as important regulators of cancer development and progression in hepatocellular carcinoma (HCC). Nevertheless, the clinical value and biological roles of LINC00978 in HCC remain unclear. In this study, we detected the expression of LINC00978 in tumor tissues and serum of HCC patients, examined the roles of LINC00978 in HCC progression and elucidated the underlying molecular mechanisms. We found that LINC00978 expression was upregulated in tumor tissues and serum of HCC patients. Higher serum levels of LINC00978 could distinguish HCC patients from hepatitis and liver cirrhosis patients and healthy controls. LINC00978 knockdown inhibited HCC cell proliferation, migration and invasion while promoted cell cycle arrest and apoptosis. Overexpression of LINC00978 led to the opposite effects. LINC00978 knockdown also inhibited HCC growth and metastasis in mouse tumor models. Mechanistically, LINC00978 bound to EZH2 and mediated its accumulation at the promoter region of p21 and E-cadherin genes, leading to the trimethylation of H27K3 and the inhibition of p21 and E-cadherin expression. Moreover, the simultaneous depletion of p21 and E-cadherin expression reversed the inhibitory effects of LINC00978 knockdown on HCC cell proliferation, migration, and invasion. Taken together, these findings suggest that LINC00978 promotes HCC progression by inhibiting p21 and E-cadherin expression via EZH2-mediated epigenetic silencing. LINC00978 may represent a novel biomarker for HCC diagnosis, prognosis, and therapy.

LncRNA MIR4435-2HG targets desmoplakin and promotes growth and metastasis of gastric cancer by activating Wnt/β-catenin signaling

Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of gastric cancer; however, their mechanisms of action remain largely unknown. The aim of this study was to identify lncRNAs involved in the tumorigenesis of gastric cancer and to investigate the signaling pathways they affect. Using microarray and RT-qPCR analyses, candidate lncRNAs were screened in paired gastric cancer tissues. The analysis revealed MIR4435-2HG to be markedly up-regulated in gastric cancer samples compared to normal stomach specimens. Increased MIR4435-2HG expression was associated with aggressive clinicopathologic features and unfavorable tumor stage. Functional experiments showed that MIR4435-2HG up-regulation enhanced gastric cancer cell proliferation, clonogenicity, and migration and invasion in vitro, as well as tumorigenicity in mice. Using RNA pull-down and mass-spectrometry analyses we found and verified a direct and novel interaction between MIR4435-2HG and desmoplakin (DSP), the most abundant desmosomal protein. Overexpression and knockdown experiments revealed opposing roles for DSP and MIR4435-2HG, unmasking a cascade through which MIR4435-2HG binds to and inhibits DSP, leading to activation of WNT/β-catenin signaling and epithelial-mesenchymal transition in gastric cancer cells. We propose that the MIR4435-2HG/DSP/WNT axis serves as a critical effector of carcinogenesis and progression of gastric cancer, and could be exploited therapeutically to improve patients' outcomes.

LINC00978 promotes bladder cancer cell proliferation, migration and invasion by sponging miR‑4288

Long noncoding RNAs regulate the occurrence and progression of numerous types of cancer, including bladder cancer (BCa). However, the role of long intergenic non‑protein coding RNA 978 (LINC00978) in BCa remains unknown. In the present study, it was identified that the LINC00978 expression level was significantly increased in BCa tissues compared with adjacent normal tissues. By performing cell proliferation, colony formation, Transwell and Matrigel assays, it was demonstrated that LINC00978 knockdown significantly inhibited the proliferation, migration and invasion of BCa cells. Conversely, overexpression of LINC00978 resulted in opposite effects. Mechanistically, it was demonstrated that LINC00978 served as a competing endogenous RNA to sponge microRNA‑4288 (miR‑4288), and LINC00978 knockdown significantly increased the expression level of miR‑4288 in BCa cells. Furthermore, it was demonstrated that the expression of LINC00978 was inversely correlated with the miR‑4288 expression level in BCa tissues. Furthermore, by performing a rescue assay, it was identified that inhibition of miR‑4288 was able to reverse the effects of LINC00978 knockdown on proliferation, migration and invasion of BCa cells. Collectively, the present study demonstrated that LINC00978 promoted BCa progression by sponging miR‑4288, suggesting that LINC00978 may represent a potential therapeutic target for BCa treatment.

Phytochemicals as Modulators of Long Non-Coding RNAs and Inhibitors of Cancer-Related Carbonic Anhydrases

Long non-coding RNAs (lncRNAs) are classified as a group of transcripts which regulate various biological processes, such as RNA processing, epigenetic control, and signaling pathways. According to recent studies, lncRNAs are dysregulated in cancer and play an important role in cancer incidence and spreading. There is also an association between lncRNAs and the overexpression of some tumor-associated proteins, including carbonic anhydrases II, IX, and XII (CA II, CA IX, and CA XII). Therefore, not only CA inhibition, but also lncRNA modulation, could represent an attractive strategy for cancer prevention and therapy. Experimental studies have suggested that herbal compounds regulate the expression of many lncRNAs involved in cancer, such as HOTAIR (HOX transcript antisense RNA), H19, MALAT1 (metastasis-associated lung adenocarcinoma transcript 1), PCGEM1 (Prostate cancer gene expression marker 1), PVT1, etc. These plant-derived drugs or phytochemicals include resveratrol, curcumin, genistein, quercetin, epigallocatechin-3-galate, camptothcin, and 3,3'-diindolylmethane. More comprehensive information about lncRNA modulation via phytochemicals would be helpful for the administration of new herbal derivatives in cancer therapy. In this review, we describe the state-of-the-art and potential of phytochemicals as modulators of lncRNAs in different types of cancers.

LncRNA MIR4435-2HG predicts poor prognosis in patients with colorectal cancer

Background

LncRNA MIR4435-2HG is observed in a variety of cancers, while its role in colorectal cancer is unknown. We aimed to demonstrate the relationship between MIR4435-2HG and colorectal cancer based on The Cancer Genome Atlas (TCGA) database.

Materials and Methods

Patients with colorectal cancer were collected from TCGA. We compared the expression of MIR4435-2HG in colorectal cancer and normal tissues with Wilcoxon rank sum test, and logistic regression was used to evaluate the relationship between MIR4435-2HG and clinicopathological characters. Moreover, Kaplan–Meier and Cox regression was performed to evaluate the correlation between MIR4435-2HG and survival rate. Gene set enrichment analysis (GSEA) was also conducted to annotate biological function of MIR4435-2HG.

Results

MIR4435-2HG level was elevated in colorectal cancer tissues. Increased level of MIR4435-2HG was significantly correlated with TNM stage (OR = 1.66 for T1/T2 vs. T3/T4; OR = 1.68 for N0 vs. N1/N2), stage (OR = 1.66 for stage 1/2 vs. stage 3/4), and carcinoembryonic antigen level before treatment (OR = 1.70 for <5 vs. ≥5) (all P-value <0.05). High MIR4435-2HG expression had a poorer progression-free survival (p = 0.048), and overall survival (OS) (P = 0.028), which were validated in the GSE92921 and GSE29621 datasets. MIR4435-2HG expression (P = 0.040, HR = 1.955 (95% CI [1.031–3.710])) was independently correlated with OS. GSEA demonstrated that the P38/MAPK pathway, the VEGF pathway, the cell adhesion molecules cams, the NOD-like receptor signaling pathway, the cell surface interactions at the vascular wall, and integrin cell surface interactions were differentially enriched in MIR4435-2HG high expression phenotype.

Conclusions

Increased MIR4435-2HG might be a potential biomarker for the diagnosis and prognosis of colorectal cancer. Moreover, MIR4435-2HG might participate in the development of colorectal cancer via the P38/MAPK and VEGF pathway.

Long non-coding RNA LINC00978 promotes cell proliferation and tumorigenesis via regulating microRNA-497/NTRK3 axis in gastric cancer

Gastric cancer (GC) is the most common gastrointestinal malignancy in the digestive system. Recent studies have proven that long non-coding RNAs (lncRNAs) are closely related to tumor growth and metastasis. The study aimed to explore the effect of LINC00978 on GC cells proliferation and tumorigenesis. LINC00978 was up-regulated in GC tissues and cell lines. Up-regulation of LINC00978 was positively correlated with low survival rate. LINC00978 silence inhibited proliferation, metastasis, and promoted apoptosis in BGC-823 cells. Additionally, LINC00978 functioned as competing endogenous RNA to inhibit miR-497 expression. Further, NTRK3 was confirmed as a target gene of miR-497. Up-regulation of NTRK3 was found in GC tissues, and the positive correlation was presented between LINC00978 and NTRK3. Further, LINC00978 promoted cell proliferation and tumor weight by regulation of NTRK3. These findings demonstrated that LINC00978 promoted cell proliferation and tumorigenesis by regulating miR-497/NTRK3 axis in GC.

Long noncoding RNA LINC00978 promotes cell proliferation and invasion in non‑small cell lung cancer by inhibiting miR‑6754‑5p

Long noncoding RNA LINC00978 has been reported to regulate the progression of several human types of cancer, including gastric and breast cancer. However, knowledge on LINC00978 in non‑small cell lung cancer (NSCLC) is limited. In the present study, it was demonstrated that LINC00978 expression was significantly upregulated in NSCLC tissues compared with the adjacent normal tissues. Furthermore, LINC00978 expression was positively correlated with the tumor, node and metastasis stage, and lymph node metastasis in NSCLC patients. Additionally, LINC00978 knockdown significantly inhibited the proliferation, migration and invasion of NSCLC cells while promoting cell apoptosis. In terms of the underlying mechanism, it was demonstrated that LINC00978 served as a competing endogenous RNA sponge for microRNA (miR)‑6754‑5p, which was downregulated in NSCLC tissues. The present study demonstrated that there was a negative correlation between LINC00978 and miR‑6754‑5p expression levels in NSCLC tissues. Additionally, it was demonstrated that inhibition of miR‑6754‑5p reversed the effects of LINC00978 knockdown on NSCLC cell proliferation, migration, invasion and apoptosis. In conclusion, results of the present study demonstrated that LINC00978 exerts an oncogenic role in NSCLC by inhibiting miR‑6754‑5p expression.

Overexpression of MAPT-AS1 is associated with better patient survival in breast cancer

Breast cancer is the most frequent malignant disease in women worldwide. It is a heterogeneous and complex genetic disease with different molecular characteristics. MAPT-AS1, a long non-coding RNA (lncRNA) existing at the anti-sense strand of the MAPT (microtubule associated protein tau) promoter region, was believed to regulate MAPT, which was associated with disease state in Parkinson's disease. But the role of MAPT-AS1 in breast cancer has never been reported. In our study we found that MAPT-AS1 is overexpressed in breast cancer but not in triple negative breast cancer (TNBC), and that high expression of MAPT-AS1 was correlated with better patient survival. In addition, the level of MAPT-AS1 was correlated with the expression of MAPT, and MAPT was associated with survival time in breast cancer. Our study suggests that MAPT-AS1 may play a role and be a potential survival predictive biomarker in breast cancer.

The Impact of lncRNA Dysregulation on Clinicopathology and Survival of Breast Cancer: A Systematic Review and Meta-analysis

Dysregulation of multiple long non-coding RNAs (lncRNAs) was reported to play major roles in breast cancer (BC). Here we aimed to collect most of the relevant literature to assess the prognostic value of lncRNAs in BC. To this end, we systematically searched PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang to identify published articles on the associations of lncRNAs with clinicopathology and/or survival of BC. Via this searching, we identified 70 articles involving 9,307 BC patients and regarding 48 lncRNAs. The expression of 41 lncRNAs was related to one or more clinicopathological parameters of BC, including tumor size; lymph node metastasis; histological grade; TNM stage; and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) statuses (p < 0.05). Dysregulation of 28 lncRNAs was associated with overall survival, and abnormal expression of 9 lncRNAs was linked to disease-free survival. Furthermore, the expression level of 3 lncRNAs was correlated with metastasis-free survival, 3 lncRNAs with relapse-free survival, and 3 lncRNAs with progression-free survival. Our analysis showed that multiple lncRNAs were significantly associated with BC clinicopathology and survival. A large-scale study is needed to verify the prognostic value of these lncRNAs in BC.

The lncRNA MIR4435-2HG promotes lung cancer progression by activating β-catenin signalling

Recently, emerging evidence has suggested that long noncoding RNAs (lncRNAs) have crucial roles in cancer progression. Here, we demonstrated that the lncRNA MIR4435-2HG was highly expressed in lung cancer tissues and correlated with histological grades and lymph node metastasis. Phenotypic analysis indicated that MIR4435-2HG knockdown inhibited lung cancer cell proliferation and invasion in vitro and in vivo. Notably, MIR4435-2HG knockdown suppressed the EMT (epithelial-mesenchymal transition) process and cancer stem cell traits of lung cancer cells. Mechanistically, MIR4435-2HG knockdown decreased the transactivation of β-catenin. MIR4435-2HG interacted with β-catenin and thus prevented its degradation by the proteasome system. Our findings highlight the important roles and mechanisms of MIR4435-2HG in lung cancer progression. High expression of lncRNA MIR4435-2HG correlates with lung cancer progression MIR4435-2HG promotes lung cancer cells proliferation and invasion MIR4435-2HG knockdown suppresses the EMT process and cancer stem cell traits MIR4435-2HG knockdown inhibits the β-catenin signalling.

Polymorphism in lncRNA AC008392.1 and its interaction with smoking on the risk of lung cancer in a Chinese population

Purpose

To evaluate the association between rs7248320 in lncRNA AC008392.1 and the risk of lung cancer, this case–control study was carried out in a Chinese population. This study also evaluated the gene–environment interaction between rs7248320 and exposure to smoking status on the risk of lung cancer.

Patients and methods

We conducted a hospital-based case–control study including 512 lung cancer cases and 588 healthy controls. The association between rs7248320 and the risk of lung cancer was analyzed, and the gene–environment interaction was estimated on an additive scale.

Results

The variant genotype of rs7248320 was significantly related to the risk of non-small-cell lung cancer (NSCLC). Individuals carrying homozygous GG genotype had decreased risk of NSCLC, compared with individuals carrying the homozygous wild AA genotype/heterozygote GA genotype (adjusted odds ratio [OR] =0.653, 95% confidence interval [CI] =0.442–0.966, P=0.033). Moreover, in the subgroup of ages, there were statistically significant associations between rs7248320 and the risk of lung cancer and NSCLC in the population over 60 years of age. Compared with individuals carrying genotypes AA/GA, individuals with genotype GG had the lower risk of lung cancer and NSCLC (adjusted ORs were 0.579 and 0.433, 95% CIs were 0.338–0.994 and 0.231–0.811, P-values were 0.048 and 0.009, respectively). Compared with homozygote AA, the homozygote GG was associated with a decreased risk in NSCLC (OR =0.456, 95% CI =0.235–0.887, P=0.021). There were no statistically significant results in gene–environment interactions on an additive scale.

Conclusion

These findings suggest that lncRNA AC008392.1 rs7248320 may be involved in genetic susceptibility to NSCLC in a Chinese population.

NEAT1 contributes to breast cancer progression through modulating miR-448 and ZEB1

Breast cancer is a kind of common female cancers. Increasing evidence has exhibited that lncRNAs exert a crucial role in breast cancer. So far, the mechanism of lncRNAs in breast cancer is still not well established. In our current study, we focused on the biological role of lncRNA Nuclear Enriched Abundant Transcript 1 (NEAT1) in breast cancer. We observed that NEAT1 levels were significantly increased in human breast cancer cells including MCF-7, MDA-MB-453, MDA-MB-231, and SKBR3 cells compared to normal mammary epithelial cells MCF-10A while miR-448 was decreased. We found that downregulation of NEAT1 was able to inhibit the growth of breast cancer cells and miR-448 mimic exerted the similar function. Bioinformatics analysis and dual luciferase reporter assays confirmed the negative correlation between NEAT1 and miR-448 in vitro. In addition, ZEB1 was predicted as a novel mRNA target of miR-448. Overexpression of NEAT1 can induce breast cancer cell growth, migration, and invasion by inhibiting miR-448 and upregulating ZEB1. It was demonstrated that NEAT1 can increase ZEB1 levels while miR-448 mimic can repress ZEB1. It was speculated in our study that NEAT1 can serve as a competing endogenous lncRNA (ceRNA) to modulate ZEB1 by sponging miR-448 in breast cancer. To conclude, we uncovered that NEAT1 participated in breast cancer progression by regulating miR-448 and ZEB1. NEAT1 can be provided as a vital biomarker in breast cancer diagnosis and treatment therapy.

Long non-coding RNA NNT-AS1 affects progression of breast cancer through miR-142-3p/ZEB1 axis

Some evidences have been provided to verify the effects of lncRNA NNT-AS1 on cancer progression. However, the crucial impacts of NNT-AS1 on the malignancy of breast cancer have not been elaborated. This study aims to detect the expression pattern and functional effects of NNT-AS1 in breast cancer. qRT-PCR analysis was applied to detect the expression of NNT-AS1 in both BC tissues and matched normal tissues. Loss of function assay was carried out to detect the effects of silenced NNT-AS1 on proliferation, metastasis and EMT process of BC cells. To understand the functional mechanism of NNT-AS1, mechanism assays were designed and performed in BC cells. Subcellular fractionation assay demonstrated that NNT-AS1 was located in the cytoplasm of BC cells. Therefore, NNT-AS1 might exert ceRNA functions in BC cells. To validate this hypothesis, we found the combination between NNT-AS1 and miR-142-3p through conducting bioinformatics analysis, RIP and luciferase reporter assays. Similarly, the combination between miR-142-3p and ZEB1 was verified. Finally, the recue assays were carried out to demonstrate the effects of NNT-AS1/miR-142-3p/ZEB1 axis on the biological behaviors of BC cells. All the above findings revealed a fact that NNT-AS1 affects breast cancer progression through modulating miR-142-3p/ZEB1 axis.

Long non-coding RNA BRAF-regulated lncRNA 1 promotes lymph node invasion, metastasis and proliferation, and predicts poor prognosis in breast cancer

Long non-coding RNAs (lncRNAs) are primary regulators of cancer development via their involvement in almost every aspect of cell biology. Recent studies have indicated that lncRNAs serve pivotal roles in breast cancer (BC) progression; however, to the best of our knowledge, the role of the lncRNA BRAF-regulated lncRNA 1 (BANCR) in BC has not yet been elucidated. The present study revealed that BANCR was overexpressed in BC cell lines and tissues, and could promote the clinical progression of disease, including increases in tumor size, lymph node metastasis and Tumor-Node-Metastasis stage. Furthermore, high BANCR expression was demonstrated to be associated with poor overall survival rates and early recurrence of BC in patients. Additionally, univariate and multivariate COX regression analyses identified high BANCR expression as an independent risk factor of poor prognosis of patients with BC. In addition, to verify the function of BANCR in BC cell lines, BANCR expression was silenced using short hairpin RNAs in MDA-MB-231 cells and overexpressed in MDA-MB-468 cells. An MTT assay and colony formation assay indicated that BANCR knockdown could suppress the proliferation of BC cells, whereas BANCR upregulation induced the proliferation of BC cells. Furthermore, BANCR silencing also reduced the migration and invasion of BC cells, as demonstrated via transwell migration and invasion assays. Consistently, the migration and invasion of BC cells increased upon BANCR ectopic overexpression in MDA-MB-468 cells. Mechanistically, matrix metallopeptidase 2/9 and epithelial-mesenchymal transition markers may be the potential targets of BANCR in regulating BC metastasis. In conclusion, BANCR overexpression could promote the clinical progression, metastasis and proliferation of BC and indicate poor prognosis of patients with BC. BANCR may therefore be a potential prognostic marker and therapeutic target of patients with BC.

Long Noncoding RNA FOXC2-AS1 Predicts Poor Survival in Breast Cancer Patients and Promotes Cell Proliferation

Breast cancer (BC) is the most common malignant tumor in women. Recently, long noncoding RNAs (lncRNAs) have been proposed as critical regulators in biological processes, including tumorigenesis. FOXC2-AS1, a single antisense oligonucleotide RNA transcribed from the negative strand of forkhead box protein C2 (FOXC2), has been identified as an oncogene in osteosarcoma. In the present study, we investigated the prognosis value and biological role of FOXC2-AS1 in BC. Our findings revealed that FOXC2-AS1 was significantly increased in BC tissues and cell lines, and Kaplan–Meier survival analysis indicated that a high level of FOXC2-AS1 was associated with poor prognosis of BC patients. Loss of function revealed that silenced FOXC2-AS1 significantly suppressed the proliferation ability, and flow cytometric analysis illustrated the influence of FOXC2-AS1 on cell cycle and apoptosis rate. Finally, we found that cyclin D1, cyclin D2, and cyclin D3 were all partly positively modulated by FOXC2-AS1 in BC. Collectively, FOXC2-AS1 may serve as a promising prognostic biomarker and therapeutic target for BC patients.

Epigenetics of breast cancer: Biology and clinical implication in the era of precision medicine

In the last years, mortality from breast cancer has declined in western countries as a consequence of a more widespread screening resulting in earlier detection, as well as an improved molecular classification and advances in adjuvant treatment. Nevertheless, approximately one third of breast cancer patients will develop distant metastases and eventually die for the disease. There is now a compelling body of evidence suggesting that epigenetic modifications comprising DNA methylation and chromatin remodeling play a pivotal role since the early stages of breast cancerogenesis. In addition, recently, increasing emphasis is being placed on the property of ncRNAs to finely control gene expression at multiple levels by interacting with a wide array of molecules such that they might be designated as epigenetic modifiers. In this review, we summarize the current knowledge about the involvement of epigenetic modifications in breast cancer, and provide an overview of the significant association of epigenetic traits with the breast cancer clinicopathological features, emphasizing the potentiality of epigenetic marks to become biomarkers in the context of precision medicine.

Long noncoding RNA LINC00978 promotes cancer growth and acts as a diagnostic biomarker in gastric cancer

OBJECTIVES

Long noncoding RNAs (lncRNAs) play important roles in cancer development and progression. The deregulated expression of LINC00978 has been reported in human cancers. However, the expression pattern and biological roles of LINC00978 in gastric cancer (GC) remain unclear. In this study, we investigated the potential roles and clinical value of LINC00978 in gastric cancer.

MATERIALS AND METHODS

QRT-PCR was performed to investigate the expression of LINC00978 in gastric cancer cell lines, tissues and serum samples. Cell counting, colony formation, transwell migration and matrigel invasion assays were performed to determine the effects of shRNA-mediated knockdown of LINC00978 on gastric cancer cell functions. In vivo tumour growth assay was also conducted. Flow cytometry, immunohistochemistry, western blot and qRT-PCR were used for potential mechanism study.

RESULTS

LINC00978 expression level was elevated in GC tumour tissues, serum samples and cell lines. The expression level of LINC00978 was significantly correlated with tumour size (P = 0.02), lymphatic metastasis (P = 0.009) and TNM stage (P = 0.009). LINC00978 knockdown inhibited the proliferation of GC cells by suppressing cell cycle progression and inducing apoptosis. LINC00978 knockdown also inhibited the migration and invasion of GC cells. In addition, LINC00978 knockdown inhibited the activation of TGF-β/SMAD signalling pathway and the process of epithelial-mesenchymal transition (EMT) in GC cells. Moreover, the in vivo tumorigenicity of LINC00978 knockdown GC cells in mice was significantly decreased.

CONCLUSIONS

LINC00978 promotes gastric cancer progression and may serve as a potential biomarker for GC.

Long non-coding RNA HOXA11-AS promotes the proliferation HCC cells by epigenetically silencing DUSP5

Hepatocellular carcinoma has been identified as the fifth most common cancer in men and the ninth in women worldwide. Despite many efforts have been made in recent years, the overall survival rate of patients with hepatocellular carcinoma still remain unsatisfied. Therefore, exploring the mechanisms underlying the progression of hepatocellular carcinoma is essential for developing novel treatments to improve patient prognosis. HOXA11-AS, transcribed from the opposite strand of the protein-coding gene HOXA11, has been identified to be associated with the malignant characteristics of several cancers. However, the biological role and molecular mechanism of HOXA11-AS in hepatocellular carcinoma still need to be further investigated. In the current study, the expression of HOXA11-AS in the hepatocellular carcinoma cell lines and tissues was measured by quantitative real-time PCR. Loss-of-function and gain-of-function approaches were applied to investigate the proliferative function of HOXA11-AS in hepatocellular carcinoma cells. Results from flow cytometric analysis of apoptosis and cell cycle distribution revealed that HOXA11-AS promoted hepatocellular carcinoma cells proliferation through regulating cell cycle and apoptosis. Gene chip technology and quantitative real-time PCR confirmed that DUSP5 was a downstream target of HOXA11-AS. RNA immune co-precipitation assays, RNA pull-down and Chromatin immunoprecipitation assays confirmed that HOXA11-AS could recruit EZH2 to the promoter region of DUSP5, which therefore suppressed the transcription of DUSP5. Collectively, these findings revealed that HOXA11-AS functions as an oncogene in hepatocellular carcinoma through interacting with polycomb-repressive complex2.

Long non‑coding RNA HOTTIP promotes hepatocellular carcinoma tumorigenesis and development: A comprehensive investigation based on bioinformatics, qRT‑PCR and meta‑analysis of 393 cases

HOTTIP functions as an independent biomarker in multiple cancers. However, the role of HOTTIP in hepatocellular carcinoma (HCC) remains unclear. In this study, we sought to investigate the HOTTIP expression in HCC and normal liver. We combined quantitative reverse transcription-polymerase chain reactions (qRT-PCR), Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA), Multi Experiment Matrix (MEM) and Oncomine database to assess the clinical role and the potential molecular mechanism of HOTTIP in HCC. Furthermore, a meta-analysis was performed to evaluate the relationship between HOTTIP and HCC tumorigenesis and development. Additionally, bioinformatics analysis, which contained Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and network analysis, were applied to investigate the underlying functions, pathways and networks of the potential genes. HOTTIP was obviously upregulated in HCC. A statistically significant higher expression of HOTTIP was found in TNM (III +IV), age (≥60), sex (male), race (white) and cirrhosis (no) compared to the control groups (P<0.05). Furthermore, the meta-analysis of 393 cases from multiple centers indicated that HOTTIP had high diagnostic value in HCC. Additionally, according to GO and KEGG analyses, we found that the most strongly enriched functional terms were gland development, transcription factor activity and extrinsic to membrane. Also, the HOTTIP co-expressed genes were significantly related to PPAR signaling pathway. We speculate that HOTTIP might play a vital part in HCC via regulating various pathways, especially PPAR signaling pathway. However, the detailed mechanism should be confirmed by functional experiments.