Knockdown of linc00152 inhibits the progression of gastric cancer by regulating microRNA-193b-3p/ETS1 axis

LINC00152: Potential driver oncogene in pan-cancer

Long noncoding RNAs (lncRNA) are a class of non-coding RNAs greater than 200 bp in length with limited peptide-coding function. The transcription of LINC00152 is derived from chromosome 2p11.2. Many studies prove that LINC00152 influences the progression of various tumors via promoting the tumor cells malignant phenotype, chemoresistance, and immune escape. LINC00152 is regulated by multiple transcription factors and DNA hypomethylation. In addition, LINC00152 participates in the regulation of complex molecular signaling networks through epigenetic regulation, protein interactions, and competitive endogenous RNA (ceRNA). Here, we provide a systematic review of the upstream regulatory factors of LINC00152 expression level in different types of tumors. In addition, we revisit the main functions and mechanisms of LINC00152 as driver oncogene and biomarker in pan-cancer. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Methods > RNA Analyses in Cells RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.

The landscape of lncRNAs in gastric cancer: from molecular mechanisms to potential clinical applications

Gastric cancer (GC) is a highly prevalent and deadly malignant neoplasm worldwide. Currently, long non-coding RNAs (lncRNAs) have recently been identified as crucial regulators implicated in GC development and progression. Dysregulated expression of lncRNAs is commonly associated with enhanced tumor migration, invasiveness, and therapy resistance, highlighting their potential as promising targets for clinical applications. This review offers a comprehensive historical overview of lncRNAs in GC, describes the molecular mechanisms, and discusses the prospects and challenges of establishing lncRNAs as precision biomarkers.

LncRNA MIR155HG Overexpression Promotes Proliferation, Migration, and Chemoresistance in Gastric Cancer Cells

Long non-coding RNAs are thought to play a vital role in a variety of human malignancies. Studies have shown that MIR155 host gene (MIR155HG) acts as an oncogene in several cancers, but the function and its mechanism of MIR155HG in gastric cancer (GC) is still poorly understood. In this study, we determined the biological functions and underlying mechanisms of MIR155HG in GC cells. We found that expression levels of MIR155HG was increased markedly in GC patients' serum. In vitro and in vivo studies demonstrated that MIR155HG modulated the malignant phenotype of GC cells, such as cell proliferation, colony forming ability, cell migration ability, and tumor growth in nude mice. Next, our results revealed that NF-κB and STAT3 signaling pathways could be involved in regulating the malignant behavior of GC cells. Our rescue experiments showed that inhibiting NF-κB and STAT3 signaling pathways attenuated the phenotypes caused by MIR155HG overexpression. Moreover, cytotoxicity and apoptosis assays revealed overexpression of MIR155HG reduced the apotosis of GC cells induced by cisplatin and 5-FU. Together, our studies suggested that MIR155HG overexpression promoted proliferation, migration, and chemoresistance of GC cells. These results might provide a lncRNA-based target for GC treatment in future.

A review on the role of LINC00152 in different disorders

LINC00152 is an important lncRNA in human disorders. It is mainly regarded as a tumor-promoting lncRNA. Mechanistically, LINC00152 serves as a molecular sponge for miR-143a-3p, miR-125a-5p, miR-139, miR-215, miR-193a/b-3p, miR-16-5p, miR-206, miR-195, miR-138, miR-185-5p, miR-103, miR-612, miR-150, miR-107, miR-205-5p and miR-153-3p. In addition, it can regulate activity of mTOR, EGFR/PI3K/AKT, ERK/MAPK, Wnt/β-Catenin, EGFR, NF-κB, HIF-1 and PTEN. In this review, we provide a concise but comprehensive explanation about the role of LINC00152 in tumor development and progression as well as its role in the pathology of non-malignant conditions with the aim of facilitating the clinical implementation of this lncRNA as a diagnostic or prognostic tumor marker and therapeutic target.

Phosphorylation-mediated interaction between human E26 transcription factor 1 and specific protein 1 is required for tumor cell migration

Transcription factors, human E26 transcription factor 1 (Ets1) and specific protein 1 (Sp1), are known to induce gene expression in tumorigenicity. High Ets1 expression is often associated with colorectal tumorigenesis. In this study, we discover that metastasis and clone formation in SW480 cells mainly depend on the direct interaction between Ets1 and Sp1 instead of high Ets1 expression. The interaction domains are further addressed to be the segment at Sp1(626-708) and the segment at Ets1(244-331). In addition, the phosphorylation inhibition of Ets1 at Tyr283 by either downregulation of Src kinase or Src family inhibitor treatment decreases the interaction between Sp1 and Ets1 and suppresses SW480 migration. Either administration or overexpression of the peptides harboring the interaction segment strongly inhibits the colony formation and migration of SW480 cells. Our findings suggest that the interaction between Ets1 and Sp1 rather than Ets1 alone promotes transformation in SW480 cells and provide new insight into the Ets1 and Sp1 interaction as an antitumour target in SW480 cells.

Regulatory Roles of Noncoding RNAs in the Progression of Gastrointestinal Cancers and Health Disparities

Annually, more than a million individuals are diagnosed with gastrointestinal (GI) cancers worldwide. With the advancements in radio- and chemotherapy and surgery, the survival rates for GI cancer patients have improved in recent years. However, the prognosis for advanced-stage GI cancers remains poor. Site-specific GI cancers share a few common risk factors; however, they are largely distinct in their etiologies and descriptive epidemiologic profiles. A large number of mutations or copy number changes associated with carcinogenesis are commonly found in noncoding DNA regions, which transcribe several noncoding RNAs (ncRNAs) that are implicated to regulate cancer initiation, metastasis, and drug resistance. In this review, we summarize the regulatory functions of ncRNAs in GI cancer development, progression, chemoresistance, and health disparities. We also highlight the potential roles of ncRNAs as therapeutic targets and biomarkers, mainly focusing on their ethnicity-/race-specific prognostic value, and discuss the prospects of genome-wide association studies (GWAS) to investigate the contribution of ncRNAs in GI tumorigenesis.

CircAGFG1 Promotes Osteosarcoma Progression and Stemness by Competing with miR-302a-3p to Upregulate the Expression of LATS2

This study aimed to investigate the effect of circRNA (circAGFG1) on the proliferation, migration, invasion, and cell stemness of osteosarcoma cells by targeting miR-302a to regulate LATS2. The expression of circAGFG1 in osteosarcoma cells and normal osteoblasts was detected by real-time fluorescent quantitative PCR (RT-qPCR). Cell proliferation, clone formation, and invasion were detected by CCK-8, clone formation, and cell invasion assays. In vivo tumor formation assay was used to detect the effect of circAGFG1 on tumor growth. The expression level of circAGFG1 was upregulated in osteosarcoma cells. The downregulation of circAGFG1 inhibited the proliferation, invasion, and migration of osteosarcoma cells. The overexpression of circAGFG1 enhanced the stemness of osteosarcoma cells. CircAGFG1 was specifically bound to miR-302a to regulate the expression activity of miR-302a. MiR-302a specifically bound to the 3'UTR of LATS2 and inhibited the expression of LATS2. The overexpression of miR-302a reversed the effect of circAGFG1 on the proliferation, invasion, and migration of osteosarcoma cells. CircAGFG1 regulated the expression of LATS2 by miR-302a, thereby regulating the proliferation, migration, and invasion of osteosarcoma cells.

ZNF750 facilitates carcinogenesis via promoting the expression of long non-coding RNA CYTOR and influences pharmacotherapy response in colon adenocarcinoma

The epidermal cell differentiation regulator zinc finger protein 750 (ZNF750) is a transcription factor containing the Cys2His2 (C2H2) domain, the zinc finger structure of which is located at the N-terminal 25‍‍-‍46 amino acids of ZNF750. It can promote the expression of differentiation-related factors while inhibiting the expression of progenitor cell-related genes. ZNF750 is directly regulated by p63 (encoded by the TP63 gene, belonging to the TP53 superfamily). The Krüppel-like factor 4 (KLF4), repressor element-1 (RE-1)‍-silencing transcription factor (REST) corepressor 1 (RCOR1), lysine demethylase 1A (KDM1A), and C-terminal-binding protein 1/2 (CTBP1/2) chromatin regulators cooperate with ZNF750 to repress epidermal progenitor genes and activate the expression of epidermal terminal differentiation genes (Sen et al., 2012; Boxer et al., 2014). Besides, ZNF750 and the regulatory network composed of bone morphogenetic protein (BMP) signaling pathway, long non-coding RNAs (lncRNAs) (anti-differentiation non-coding RNA (ANCR) and tissue differentiation-inducing non-protein coding RNA (TINCR)), musculoaponeurotic fibrosarcoma oncogene (MAF)/MAF family B (MAFB), grainy head-like 3 (GRHL3), and positive regulatory domain zinc finger protein 1 (PRDM1) jointly promote epidermal cell differentiation (Sen et al., 2012).

The interaction between ETS transcription factor family members and microRNAs: A novel approach to cancer therapy

In cancer biology, ETS transcription factors promote tumorigenesis by mediating transcriptional regulation of numerous genes via the conserved ETS DNA-binding domain. MicroRNAs (miRNAs) act as posttranscriptional regulators to regulate various tumor-promoting or tumor-suppressing factors. Interactions between ETS factors and miRNAs regulate complex tumor-promoting and tumor-suppressing networks. This review discusses the progress of ETS factors and miRNAs in cancer research in detail. We focused on characterizing the interaction of the miRNA/ETS axis with competing endogenous RNAs (ceRNAs) and its regulation in posttranslational modifications (PTMs) and the tumor microenvironment (TME). Finally, we explore the prospect of ETS factors and miRNAs in therapeutic intervention. Generally, interactions between ETS factors and miRNAs provide fresh perspectives into tumorigenesis and development and novel therapeutic approaches for malignant tumors.

LINC00152 Drives a Competing Endogenous RNA Network in Human Hepatocellular Carcinoma

Genomic and epigenomic studies revealed dysregulation of long non-coding RNAs in many cancer entities, including liver cancer. We identified an epigenetic mechanism leading to upregulation of the long intergenic non-coding RNA 152 (LINC00152) expression in human hepatocellular carcinoma (HCC). Here, we aimed to characterize a potential competing endogenous RNA (ceRNA) network, in which LINC00152 exerts oncogenic functions by sponging miRNAs, thereby affecting their target gene expression. Database and gene expression data of human HCC were integrated to develop a potential LINC00152-driven ceRNA in silico. RNA immunoprecipitation and luciferase assay were used to identify miRNA binding to LINC00152 in human HCC cells. Functionally active players in the ceRNA network were analyzed using gene editing, siRNA or miRNA mimic transfection, and expression vectors in vitro. RNA expression in human HCC in vivo was validated by RNA in situ hybridization. Let-7c-5p, miR-23a-3p, miR-125a-5p, miR-125b-5p, miR-143a-3p, miR-193-3p, and miR-195-5p were detected as new components of the potential LINC00152 ceRNA network in human HCC. LINC00152 was confirmed to sponge miR143a-3p in human HCC cell lines, thereby limiting its binding to their respective target genes, like KLC2. KLC2 was identified as a central mediator promoting pro-tumorigenic effects of LINC00152 overexpression in HCC cells. Furthermore, co-expression of LINC00152 and KLC2 was observed in human HCC cohorts and high KLC2 expression was associated with shorter patient survival. Functional assays demonstrated that KLC2 promoted cell proliferation, clonogenicity and migration in vitro. The LINC00152-miR-143a-3p-KLC2 axis may represent a therapeutic target in human HCC.

Functional Screen for microRNAs Suppressing Anchorage-Independent Growth in Human Cervical Cancer Cells

The progression of anchorage-dependent epithelial cells to anchorage-independent growth represents a critical hallmark of malignant transformation. Using an in vitro model of human papillomavirus (HPV)-induced transformation, we previously showed that acquisition of anchorage-independent growth is associated with marked (epi)genetic changes, including altered expression of microRNAs. However, the laborious nature of the conventional growth method in soft agar to measure this phenotype hampers a high-throughput analysis. We developed alternative functional screening methods using 96- and 384-well ultra-low attachment plates to systematically investigate microRNAs regulating anchorage-independent growth. SiHa cervical cancer cells were transfected with a microRNA mimic library (n = 2019) and evaluated for cell viability. We identified 84 microRNAs that consistently suppressed growth in three independent experiments. Further validation in three cell lines and comparison of growth in adherent and ultra-low attachment plates yielded 40 microRNAs that specifically reduced anchorage-independent growth. In conclusion, ultra-low attachment plates are a promising alternative for soft-agar assays to study anchorage-independent growth and are suitable for high-throughput functional screening. Anchorage independence suppressing microRNAs identified through our screen were successfully validated in three cell lines. These microRNAs may provide specific biomarkers for detecting and treating HPV-induced precancerous lesions progressing to invasive cancer, the most critical stage during cervical cancer development.

Circ_0000745 regulates NOTCH1-mediated cell proliferation and apoptosis in pediatric T-cell acute lymphoblastic leukemia through adsorbing miR-193b-3p

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is a highly proliferative hematologic malignancy. Circular RNA hsa_circ_0000745 (circ_0000745) has been reported as an oncogene in acute lymphoblastic leukemia (ALL). However, whether circ_0000745 can drive T-ALL progression by controlling notch receptor 1 (NOTCH1) expression is unclear.

METHODS

Relative expression of circ_0000745 and NOTCH1 in bone marrow (BM) samples and T-ALL cells was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Loss- and gain-of-function experiments were executed to evaluate the effects of circ_0000745 and NOTCH1 on T-ALL cell proliferation and apoptosis. The microRNAs (miRs) that might jointly interact with circ_0000745 and NOTCH1 were predicted by bioinformatics analysis and verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

Circ_0000745 and NOTCH1 were overexpressed in T-ALL BM and T-ALL cells. Functionally, both circ_0000745 and NOTCH1 overexpression promoted T-ALL cell proliferation and curbed T-ALL cell apoptosis. In contrast, both circ_0000745 and NOTCH1 silencing restrained T-ALL cell proliferation and induced T-ALL cell apoptosis. Furthermore, circ_0000745 could control T-ALL cell proliferation and apoptosis through regulating NOTCH1 expression. Importantly, circ_0000745 regulated NOTCH1 expression by sponging miR-193b-3p.

CONCLUSION

Our findings proposed a novel model in which circ_0000745 promoted cell proliferation and curbed cell apoptosis via upregulating NOTCH1 through serving as a miR-193b-3p sponge in T-ALL.

The LINC00152/miR-138 Axis Facilitates Gastric Cancer Progression by Mediating SIRT2

Gastric cancer (GC) is the most common gastrointestinal cancer and the main cause of tumor-related death. Exploring markers for early diagnosis and new therapeutic targets is always on the way. In the last 10 years, long noncoding RNAs (lncRNAs) have been widely proved to be involved in the progress of many tumors and are regarded as potential targets for tumor therapy. We found that LINC00152, a newly identified lncRNA, was significantly upregulated in GC tissues and affected clinicopathological characteristics in GC patients. Furthermore, we observed that LINC00152 knockdown can significantly reduce cell proliferation and promote apoptosis in human gastric cancer cells. Further bioinformatic analysis indicated that LINC00152 competitively bound with miR-138 and regulated the expression of miR-138. Moreover, SIRT2 was further proved to be a downstream target of miR-138. Overall, this study elucidates the molecular mechanism of LINC00152 underlying the malignant phenotype of GC cells by mediating miR-138/SIRT2 axis, which provides a new understanding of the role and molecular mechanism of lncRNA in GC and also provides a new way for the treatment of gastric cancer.

Silencing long non-coding RNA DLX6-AS1 or restoring microRNA-193b-3p enhances thyroid carcinoma cell autophagy and apoptosis via depressing HOXA1

Long non‐coding RNA DLX6 antisense RNA 1 (DLX6‐AS1) lists a critical position in thyroid carcinoma (TC) development. However, the overall comprehension about DLX6‐AS1, microRNA (miR)‐193b‐3p and homeobox A1 (HOXA1) in TC is not thoroughly enough. Concerning to this, this work is pivoted on DLX6‐AS1/miR‐193b‐3p/HOXA1 axis in TC cell growth and autophagy. TC tissues and adjacent normal thyroid tissues were collected, in which expression of DLX6‐AS1, miR‐193b‐3p and HOXA1 was tested, together with their interactions. TC cells were transfected with DLX6‐AS1/miR‐193b‐3p‐related oligonucleotides or plasmids to test cell growth and autophagy. Tumorigenesis in nude mice was observed. DLX6‐AS1 and HOXA1 were up‐regulated, and miR‐193b‐3p was down‐regulated in TC. Depleted DLX6‐AS1 or restored miR‐193b‐3p disturbed cell growth and promoted autophagy. DLX6‐AS1 targeted miR‐193b‐3p and positively regulated HOXA1. miR‐193b‐3p inhibition mitigated the impaired tumorigenesis induced by down‐regulated DLX6‐AS1. Tumorigenesis in nude mice was consistent with that in cells. It is clear that DLX6‐AS1 depletion hinders TC cell growth and promotes autophagy via up‐regulating miR‐193b‐3p and down‐regulating HOXA1.

Research updates on the clinical implication of long noncoding RNA in digestive system cancers and chemoresistance

Long noncoding RNAs (lncRNAs) are implicated in various biological processes, such as cell proliferation, differentiation, apoptosis, migration, and invasion. They are also key players in various biological pathways. LncRNA was considered as 'translational noise' before 1980s. It has been reported that lncRNAs are aberrantly expressed in different cancers, either as oncogene or tumor suppressor gene. Therefore, more and more lncRNAs are recognized as potential diagnostic biomarkers and/or therapeutic targets. As competitive endogenous RNA, lncRNAs can interact with microRNA to alter the expression of target genes, which may have extensive clinical implications in cancers, including diagnosis, treatment, prognosis, and chemoresistance. This review comprehensively summarizes the functions and clinical relevance of lncRNAs in digestive system cancers, especially as a potential tool to overcome chemoresistance.

The Long Non-coding RNA Cytoskeleton Regulator (CYTOR) Sponges microRNA- 206 (miR-206) to Promote Proliferation and Invasion of HP75 Cells

BACKGROUND

The role and mechanism of long non-coding RNA cytoskeleton regulator (CYTOR) in Invasive Pituitary Adenomas (IPA) have not been elucidated previously.

OBJECTIVE

This study aimed to investigate the interaction between CYTOR and miR-206 and their roles in IPA using HP75 cells as the model.

METHODS

The expression levels of CYTOR and miR-206 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in IPA tissues and cell lines. The Chi-square test was used to analyze the correlation between CYTOR expression and clinical-pathological parameters. HP75 cell proliferation was detected by Cell Counting Kit-8 assay and colony formation assay. Scratch healing experiments and Transwell assay were used to detect migration and invasion of HP75 cells. The relationship between CYTOR and miR-206 was predicted by bioinformatics and verified by qRT-PCR and the dual-luciferase reporter gene method.

RESULTS

CYTOR is up-regulated in IPA tissues and cell lines. The high expression of CYTOR is associated with adenoma invasiveness and adenoma size of the patients. Down-regulation of CYTOR decreases the proliferation, migration and invasion of HP75 cells, while up-regulation of miR-206 can inhibit proliferation, migration and invasion of HP75 cells. MiR-206 is identified as a target of CYTOR and could be negatively regulated by it in IPA.

DISCUSSION

CYTOR, as a tumor-promoting factor, facilitates the proliferation, migration and invasion of HP75 cells through sponging miR-206.

CONCLUSION

The CYTOR-miR-206 axis provides new insights into the diagnosis and treatment of IPA.

Long non-coding RNA CYTOR regulates proliferation and metastasis of colon cancer cells through regulating miRNA-105/PTEN axis

Colon cancer is a common malignancy, and its incidence and mortality have been increasing in recent years. This study aims to explore the regulation of long non-coding RNA CYTOR on proliferation and metastasis of colon cancer cells through miRNA-105/PTEN axis. Real-time quantitative PCR (qRT-PCR) disclosed that expression of CYTOR was significantly decreased in colon cancer tissues, compared with that of adjacent normal tissues, while miRNA-105 was significantly increased. Correlation study found that CYTOR was negatively correlated with miR-105. The proliferation, migration, and invasion rates of the LoVo cells with highly expressed CYTOR were significantly slower. miR-105 mimic could suppress the decrease in proliferation, migration, and invasion rates of colon cancer cells caused by overexpression of CYTOR. Additionally, the proliferation, migration, and invasion rates of the LoVo cells in miR-105 inhibition group were significantly slower. The Starbase database predicted the targeting of miR-105 by CYTOR, and qRT-PCR and dual luciferase reporter gene method were used to verify the targeting relationship of CYTOR and miRNA-105/PTEN axis. In conclusion, CYTOR can inhibit the proliferation and metastasis of colon cancer cells through targeted inhibition of the miR-105/PTEN axis.

Role of LINC00152 in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) accounts for about 85% of all lung cancer cases. The pathogenesis of NSCLC involves complex gene networks that include different types of non-coding RNAs, such as long non-coding RNAs (lncRNAs). The role of lncRNAs in NSCLC is gaining an increasing interest as their function is being explored in various human cancers. Recently, a new oncogenic lncRNA, LINC00152 (cytoskeleton regulator RNA (CYTOR)), has been identified in different tumor types. In NSCLC, the high expression of LINC00152 in tumor tissue and peripheral blood samples has been shown to be associated with worse prognoses of NSCLC patients. Overexpression of LINC00152 has been confirmed to promote the proliferation, invasion, and migration of NSCLC cells in vitro, as well as increase tumor growth in vivo. This review discusses the role of LINC00152 in NSCLC.

LncRNA CYTOR affects the proliferation, cell cycle and apoptosis of hepatocellular carcinoma cells by regulating the miR-125b-5p/KIAA1522 axis

We aimed to investigate whether lncRNA CYTOR could sponge miR-125b-5p to affect hepatocellular carcinoma (HCC) cells through targeting KIAA1522. The expression of CYTOR, miR-125b-5p and KIAA1522 in HCC cells was detected by Real-time quantitative polymerase chain reaction (RT-qPCR) analysis. KIAA1522 expression in HCC tissues was detected by immunohistochemistry. The proliferation, cell cycle and apoptosis of HCC cells after transfection were respectively detected by Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis, and related protein expression was determined by Western blot analysis. As a result, The Cancer Genome Atlas (TCGA) database indicated that expression of CYTOR and KIAA1522 was increased in HCC tissues and high expression of CYTOR and KIAA1522 was related to worse overall survival. MiR-125b-5p expression was decreased in HCC tissues, which was negatively correlated with the expression of CYTOR and KIAA1522. The proliferation and cell cycle of HCC cells were suppressed by CYTOR interference while promoted by miR-125b-5p interference and KIAA1522 overexpression. The apoptosis of HCC cells was promoted by CYTOR interference while inhibited by miR-125b-5p interference and KIAA1522 overexpression. In conclusion, CYTOR interference suppressed the proliferation and cell cycle, and promoted the apoptosis of HCC cells by regulating the miR-125b-5p/KIAA1522 axis.

LINC00152 Promotes Tumor Progression and Predicts Poor Prognosis by Stabilizing BCL6 From Degradation in the Epithelial Ovarian Cancer

Long non-coding RNA 00152 (LINC00152) is tumorigenic in multiple somatic malignancies. However, its prognostic significance and molecular mechanisms in the epithelial ovarian cancer (EOC) remain elusive. Here our study reveals that dysregulation of LINC00152 is a predictor of poor prognosis in patients with EOC and facilitates ovarian tumor growth and metastasis both in vitro and in vivo; the expression of LINC00152 positively correlates with the protein levels of BCL6 in EOC tissues and ovarian tumor cells; LINC00152 binds to Ser333 and Ser343 of BCL6 protein and stabilizes BCL6 from poly-ubiquitination thus facilitating the oncogenic functions in EOC. Moreover, overexpression of the mutant BCL6^S333A/S343A fails to rescue the reduced proliferation and invasion caused by the knockdown of endogenous BCL6 in LINC00152-overexpressing cells. Our study might not only offer clues to the network of lncRNA-protein interactions but also provide potential therapeutic targets for the tumor pharmacology.

The circRNA circ_0000291 acts as a sponge of microRNA 326 to regulate E26 transformation-specific sequence-1 expression and promote breast cancer progression

Accumulating studies authenticate that circular RNAs (circRNAs) are involved in the progression of cancers. However, their role in breast cancer (BC) remains largely unknown. In this study, real-time polymerase chain reaction was employed to detect the circ_0000291 and miR-326 expressions in BC tissues and cells. The correlation between the expression level of circ_0000291 and clinicopathological parameters of BC patients was analyzed. Western blot was used to detect the expression of E26 transformation-specific sequence-1 (ETS1), E-cadherin, N-cadherin and Vimentin in BC cells. Cell proliferation was measured using the cell counting kit-8 assay and the bromodeoxyuridine assay. Cell migration and invasion were detected by Transwell assay. The interactions between circ_0000291 and miR-326, miR-326 and ETS1 were verified using bioinformatics prediction, the dual-luciferase reporter gene assay or/and RNA binding protein immunoprecipitation assay. We demonstrated that circ_0000291 was significantly upregulated in BC, and its high expression was positively correlated with T stage and local lymph node metastasis. Functional assays validated that circ_0000291 promoted BC cell proliferation, migration and invasion. The mechanism studies indicated that circ_0000291 could decoy miR-326 and in turn upregulate the expression of ETS1. In conclusion, circ_0000291 is the novel oncogenic circRNA and promotes BC progression via modulating the miR-326/ETS1 axis.

LncRNA LINC00689 Promotes the Progression of Gastric Cancer Through Upregulation of ADAM9 by Sponging miR-526b-3p

Introduction

Increasing studies have demonstrated that noncoding RNAs, including miRNAs and lncRNAs, have vital roles in mediating cancer progression. However, the expression features and biological functions of LINC00689 in gastric cancer (GC) remain largely unknown. This study was designed to investigate the functions of LINC00689, miR-526b-3p and ADAM9 as well as their interactions in GC.

Methods

Real time PCR(RT-PCR) was used to detect the expression of LINC0068, miR-526b-3p and ADAM9 in both GC tissues or cell lines. Gain- and loss- of functions of assays were conducted to verify the role of LINC0068, miR-526b-3p and ADAM9 in GC development. Cell proliferation were determined by CCK8 assay and transwell assay and scratch wound-healing assay were used to test cell invasion and migration. Further, the relationships between LINC00689 and miR-526b-3p, miR-526b-3p and ADAM9 were predicted by bioinformatics analysis and then proved by Luciferase reporter assay and RNA Immunoprecipitation(RIP) assay.

Results

We found that LINC00689 was upregulated in GC tissues and positively correlated with advanced tumor stage and tumor size, while miR-526b-3p was downregulated. Furthermore, gain- and loss-of-function experiments revealed that LINC00689 promoted the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of GC cells, while miR-526b-3p had the opposite effects. The underlying mechanisms indicated that LINC00689 functioned as a competing endogenous RNA (ceRNA) by sponging miR-526b-3p in GC cells. Further investigations confirmed that ADAM9 was a direct target of miR-526b-3p and positively modulated the progression of GC.

Conclusion

Our study suggests that LINC00689 functions as a novel oncogenic lncRNA in the development of GC by promoting ADAM9 expression through suppression of miR-526b-3p.

Long non-coding RNA linc00152 acting as a promising oncogene in cancer progression

The incidence and mortality rate of cancer continues to gradually increase, although considerable research effort has been directed at elucidating the molecular mechanisms underlying biomarkers responsible for tumorigenesis. Accumulated evidence indicates that the long non-coding RNAs (lncRNAs), which are transcribed but not translated into functional proteins, contribute to cancer development. Recently, linc00152 (an lncRNA) was identified as a potent oncogene in various cancer types, and shown to be involved in cancer cell proliferation, invasiveness, and motility by sponging tumor-suppressive microRNAs acting as a competing endogenous RNA, binding to gene promoters acting as a transcriptional regulator, and binding to functional proteins. In this review, we focus on the oncogenic role of linc00152 in tumorigenesis and provided an overview of recent clinical studies on the effects of linc00152 expression in human cancers.

LncRNA FENDRR suppresses the progression of NSCLC via regulating miR-761/TIMP2 axis

To explore the roles of long noncoding RNA (lncRNA) FOXF1 Adjacent Non-Coding Developmental Regulatory RNA (FENDRR) in human non-small cell lung cancer (NSCLC). The levels of FENDRR in NSCLC cells and tissues were analyzed using qRT-PCR assay. The growth and colony formation abilities of NSCLC cell were analyzed by the MTT and colony formation tests. The mobility and invasiveness of NSCLC cell were analyzed using the wound closure and Transwell invasion assay. The impact of FENDRR on the tumor growth of NSCLC cells in vivo was detected using xenograft model. Bioinformatics analysis and luciferase reporter gene bioassay were selected to identify the bindings sites between miR-761 and FENDRR. Additional, the results of Transwell invasion and colony formation experiments indicated that FENDRR inhibited the aggressiveness of NSCLC depend on miR-761. Tissue inhibitor of metalloproteinase 2 (TIMP2) was identified as the downstream target of miR-761 and its level was positively regulated by FENDRR. Cotransfection assays using A549 and H1975 cells future implied that downexpression of TIMP2 rescued the aggressiveness phenotypes of NSCLC cell inhibited by FENDRR. Altogether, we demonstrated that lncRNA FENDRR suppressed the progression of NSCLC via binding to miR-761 and regulating TIMP2 expression.

Roles of E-cadherin and Noncoding RNAs in the Epithelial-mesenchymal Transition and Progression in Gastric Cancer

The epithelial–mesenchymal transition (EMT) is thought to be at the root of invasive and metastatic cancer cell spreading. E-cadherin is an important player in this process, which forms the structures that establish and maintain cell–cell interactions. A partial or complete loss of E-cadherin expression in the EMT is presumably mediated by mechanisms that block the expression of E-cadherin regulators and involve the E-cadherin-associated transcription factors. The protein is involved in several oncogenic signaling pathways, such as the Wnt/β-catenin, Rho GTPase, and EGF/EGFR, whereby it plays a role in many tumors, including gastric cancer. Such noncoding transcripts as microRNAs and long noncoding RNAs—critical components of epigenetic control of gene expression in carcinogenesis—contribute to regulation of the E-cadherin function by acting directly or through numerous factors controlling transcription of its gene, and thus affecting not only cancer cell proliferation and metastasis, but also the EMT. This review focuses on the role of E-cadherin and the non-coding RNAs-mediated mechanisms of its expressional control in the EMT during stomach carcinogenesis.

In silico identification of novel lncRNAs with a potential role in diagnosis of gastric cancer

Gastric cancer (GC) is the second leading cause of cancer-related deaths in the world. Due to the shortage of adequate symptoms in the early stages, it is diagnosed when the tumor has spread to distant organs. Early recognition of GC enhances the chance of successful treatment. Molecular mechanisms of GC are still poorly understood. LncRNAs are emerging as new players in cancer in both oncogene and tumor suppressor roles. High-throughput technologies such as RNA-Seq, have revealed thousands of lncRNAs which are dysregulated in GC. In this study, we retrieved lncRNAs obtained by High-throughput technologies from OncoLnc database. Consequently, retrieved lncRNAs were compared in literature-based databases including PubMed. As a result, two lists, including experimentally validated lncRNAs and predicted lncRNAs were provided. We found 43 predicted lncRNAs that had not been experimentally validated in GC, so far. Further Bioinformatics analyses were performed to obtain the expression profile of predicted lncRNAs in tumor and normal tissues. Also, the roles and targets of predicted lncRNAs in GC were identified by related databases. Finally, using the GEPIA database was reviewed the significant relationship of predicted lncRNAs with the survival of GC patients. By recognizing the lncRNAs involved in initiation and progression of GC, they may be considered as potential biomarkers in the GC early diagnosis or targeted treatment and lead to novel therapeutic strategies. Communicated by Ramaswamy H. Sarma.