Long non-coding RNA LUCAT1 promotes proliferation and invasion in gastric cancer by regulating miR-134-5p/YWHAZ axis

Lung cancer associated transcript 1 binds heat shock protein 90 to promote growth of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of leading causes of cancer-related death and new approaches are urgently needed, given current dearth of therapies. Long non-coding RNAs (lncRNAs) have been linked to cancer formation and impact cell regulatory pathways. We have investigated molecular mechanisms of action of "lung cancer associated transcript 1" (LUCAT1, a lncRNA) in HCC and studied the potential role of targeting these. We analyzed expression levels of LUCAT1 in TCGA dataset and another 148 HCC patients in Peking Union Medical College Hospital (PUMCH). Expression analysis using TCGA database and patient cohort revealed LUCAT1 to be upregulated in HCC. LUCAT1 levels were closely associated with clinical prognosis. Subcellular localization patterns of LUCAT1 in HCC tissues and cells were identified by RNAscope. Engineered antisense oligonucleotides (ASOs) targeting LUCAT1 were used to test anti-tumor effectiveness using in vitro and in vivo models. CHIRP-MS and RNA pull-down assays were conducted to demonstrate the mechanism of action of LUCAT1.LUCAT1 expression facilitated nuclear accumulation of HSP90. This interaction evoked persistent phosphorylation and constitutive activation of signal transducer and activator of transcription 3 (STAT3), potentially driving HCC growth and metastases. These tumor-promoting effects were substantively diminished using ASOs against LUCAT1, both in vitro and in vivo. LUCAT1 selectively boosts oncogenic property of HSP90 in driving STAT3 activation, which can be effectively and precisely inhibited by designer ASOs. We propose novel potential therapeutic avenues that are selective, cost-effective and seemingly nontoxic.

The long noncoding RNA LUCAT1 regulates endometrial receptivity via the miR-495-3p/S100P axis

Recently, interest in investigating the effects of long noncoding RNAs (lncRNAs) on endometrial receptivity (ER) has increased within the field of assisted reproductive technology. Therefore, the objective of this study is to identify and analyze the role of the lncRNA LUCAT1 and to elucidate its specific mechanism in regulating ER. Hub genes associated with ER are identified via Weighted gene co-expression network analysis (WGCNA) in two datasets downloaded from the GEO database. These hub genes identified via WGCNA were subsequently validated. The combination of a dual-luciferase assay, qRT‒PCR, western blotting, and other techniques are used to investigate the molecular mechanism by which LUCAT1 regulates S100P. In this study, LUCAT1 expression is shown to significantly affect ER, and the depletion of LUCAT1 leads to impaired ER function. Additionally, LUCAT1 is shown to act as a molecular sponge for miR-495-3p, thereby modulating the expression of S100P. This modulation influences the proliferation, migration, and invasion capabilities of Ishikawa cells, as well as the adhesion of JAR cells to endometrial cells. Therefore, LUCAT1 can regulate ER via the miR-495-3p/S100P axis, which provides experimental evidence for the identification of innovative strategies aimed at enhancing endometrial receptivity.

Recombinant human protein TCFL5-activated NRSN2-AS1 promotes esophageal cancer progression via the microRNA-874-5p/RELT regulatory axis

The incidence of esophageal cancer continues to increase worldwide. Current therapeutic approaches have limited efficacy, so in order to search for better markers of the disease, it is necessary to further elucidate its molecular pathogenesis. Regulation of gene expression by long non-coding Rnas plays a role in many diseases, however the role in esophageal cancer is unclear. The aim of this study was to elucidate the role and regulatory mechanism of long non-coding RNA NRSN2-AS1 in the progression of esophageal cancer. By real-time quantitative PCR, immunohistochemistry, RNA interference, western blotting, and double luciferase reporter gene analysis, we found that NRSN2-AS1 was up-regulated in esophageal cancer tissues and cell lines, and was closely related to disease stage and prognosis. Functional studies have shown that the silencing of NRSN2-AS1 inhibits the proliferation of esophageal cancer cells, induces apoptosis, and prevents cell migration and invasion. In mouse models, NRSN2-AS1 also promoted tumor growth. The transcription factor TCFL5 upregulates the transcription of NRSN2-AS1, which acts as a sponge for microRNA(miR)-874-5p, thereby upregulating the expression of the oncogene RELT. Activation of the NRSN2-AS1/miR-874-5p/RELT regulatory axis was validated in vivo.

Long non‑coding RNA lung cancer‑associated transcript 1 regulates ferroptosis via microRNA‑34a‑5p‑mediated GTP cyclohydrolase 1 downregulation in lung cancer cells

Ferroptosis, a recently discovered type of programmed cell death triggered by excessive accumulation of iron‑dependent lipid peroxidation, is linked to several malignancies, including non‑small cell lung cancer. Long non‑coding RNAs (lncRNAs) are involved in ferroptosis; however, data on their role and mechanism in cancer therapy remains limited. Therefore, the aim of the present study was to identify ferroptosis‑associated mRNAs and lncRNAs in A549 lung cancer cells treated with RAS‑selective lethal 3 (RSL3) and ferrostatin‑1 (Fer‑1) using RNA sequencing. The results demonstrated that lncRNA lung cancer‑associated transcript 1 (LUCAT1) was significantly upregulated in lung adenocarcinoma and lung squamous cell carcinoma tissues. Co‑expression analysis of differentially expressed mRNAs and lncRNAs suggested that LUCAT1 has a crucial role in ferroptosis. LUCAT1 expression was markedly elevated in A549 cells treated with RSL3, which was prevented by co‑incubation with Fer‑1. Functionally, overexpression of LUCAT1 facilitated cell proliferation and reduced the occurrence of ferroptosis induced by RSL3 and Erastin, while inhibition of LUCAT1 expression reduced cell proliferation and increased ferroptosis. Mechanistically, downregulation of LUCAT1 resulted in the downregulation of both GTP cyclohydrolase 1 (GCH1) and ferroptosis suppressor protein 1 (FSP1). Furthermore, inhibition of LUCAT1 expression upregulated microRNA (miR)‑34a‑5p and then downregulated GCH1. These results indicated that inhibition of LUCAT1 expression promoted ferroptosis by modulating the downregulation of GCH1, mediated by miR‑34a‑5p. Therefore, the combination of knocking down LUCAT1 expression with ferroptosis inducers may be a promising strategy for lung cancer treatment.

MiR-134-5p inhibits the malignant phenotypes of osteosarcoma via ITGB1/MMP2/PI3K/Akt pathway

Micro RNAs (miRs) have been implicated in various tumorigenic processes. Osteosarcoma (OS) is a primary bone malignancy seen in adolescents. However, the mechanism of miRs in OS has not been fully demonstrated yet. Here, miR-134-5p was found to inhibit OS progression and was also expressed at significantly lower levels in OS tissues and cells relative to normal controls. miR-134-5p was found to reduce vasculogenic mimicry, proliferation, invasion, and migration of OS cells, with miR-134-5p knockdown having the opposite effects. Mechanistically, miR-134-5p inhibited expression of the ITGB1/MMP2/PI3K/Akt axis, thus reducing the malignant features of OS cells. In summary, miR-134-5p reduced OS tumorigenesis by modulation of the ITGB1/MMP2/PI3K/Akt axis, suggesting the potential for using miR-134-5p as a target for treating OS.

Curcumin targets miR-134-5p to suppress the progression of colorectal cancer through regulating the CDCA3/CDK1 pathway

It has been reported the anti-tumor action of curcumin on colorectal cancer. In this study, we aimed to explore the potential mechanisms underlying curcumin in the development of colorectal cancer. CCK-8, EdU, flow cytometry, and transwell invasion assays were conducted to investigate the function role of curcumin in cell proliferation, apoptosis, and invasion. The level of miR-134-5p and CDCA3 was determined using RT-qPCR analysis. Western blot was applied for detecting the levels of c-myc, MMP9, CDCA3, and CDK1. Dual-luciferase reporter assay was used to evaluate the relationship between miR-134-5p and CDCA3, and IP assay was performed to examine the interaction between CDCA3 and CDK1. Additionally, SW620 cells were injected into the mice to form the xenograft tumor model. Curcumin treatment repressed cell growth and invasion, and induced cell apoptosis in HCT-116 and SW620 cells. Curcumin elevated miR-134-5p expression and restrained CDCA3 expression in HCT-116 and SW620 cells. MiR-134-5p inhibitor or CDCA3 overexpression could restore the effects of curcumin on cell growth, apoptosis, and invasion in HCT-116 and SW620 cells. MiR-134-5p targeted CDCA3, and CDCA3 could rescue the repressive effects of miR-134-5p on the progression of colorectal cancer. Moreover, CDCA3 interacted with CDK1, and CDK1 overexpression blocked the suppressive effects of CDCA3 downregulation on the development of colorectal cancer. In addition, curcumin treatment repressed tumor growth in colorectal cancer via increasing miR-134-5p and downregulating CDCA3 and CDK1 expression in vivo. Our findings provided the evidence that curcumin upregulated miR-134-5p to inhibit the progression of colorectal cancer by regulating CDCA3/CDK1 pathway.

LncRNA TDRKH-AS1 promotes breast cancer progression via the miR-134-5p/CREB1 axis

BACKGROUND

Breast cancer (BC) is a prevalent malignancy with complex etiology and varied clinical behavior. Long non-coding RNAs (lncRNAs) have emerged as key regulators in cancer progression, including BC. Among these, lncRNA TDRKH-AS1 has been implicated in several cancers, but its role in BC remains unclear.

METHODS

We conducted a comprehensive investigation to elucidate the role of TDRKH-AS1 in BC. Clinical samples were collected from BC patients, and BC cell lines were cultured. Bioinformatics analysis using the starBase database was carried out to assess TDRKH-AS1 expression levels in BC tissue samples. Functional experiments, including knockdown, colony formation, CCK-8, Transwell, and wound-healing assays, were conducted to determine the role of TDRKH-AS1 in BC cell proliferation and invasion. Luciferase reporter and RIP assays were used to examine the interactions between TDRKH-AS1 and miR-134-5p. In addition, the downstream target gene of miR-134-5p, cAMP response element-binding protein 1 (CREB1), was identified and studied using various methods, including RT-qPCR, immunoprecipitation, and rescue experiments. In vivo experiments using mouse tumor xenograft models were conducted to examine the role of TDRKH-AS1 in BC tumorigenesis.

RESULTS

TDRKH-AS1 was found to be significantly upregulated in BC tissues and cell lines. High TDRKH-AS1 expression correlated with advanced BC stages and worse patient outcomes. Knockdown of TDRKH-AS1 led to decreased BC cell proliferation and invasion. Mechanistically, TDRKH-AS1 acted as a sponge for miR-134-5p, thereby reducing the inhibitory effects of miR-134-5p on CREB1 expression. Overexpression of CREB1 partially rescued the effects of TDRKH-AS1 knockdown in BC cells. In vivo studies further confirmed the tumor-promoting role of TDRKH-AS1 in BC.

CONCLUSIONS

Our study unveiled a novel regulatory axis involving TDRKH-AS1, miR-134-5p, and CREB1 in BC progression. TDRKH-AS1 functioned as an oncogenic lncRNA by promoting BC cell proliferation and invasion through modulation of the miR-134-5p/CREB1 axis. These findings highlighted TDRKH-AS1 as a potential diagnostic biomarker and therapeutic target for BC treatment.

Non-coding RNAs' function in cancer development, diagnosis and therapy

While previous research on cancer biology has focused on genes that code for proteins, in recent years it has been discovered that non-coding RNAs (ncRNAs)play key regulatory roles in cell biological functions. NcRNAs account for more than 95% of human transcripts and are an important entry point for the study of the mechanism of cancer development. An increasing number of studies have demonstrated that ncRNAs can act as tumor suppressor genes or oncogenes to regulate tumor development at the epigenetic level, transcriptional level, as well as post-transcriptional level. Because of the importance of ncRNAs in cancer, most clinical trials have focused on ncRNAs to explore whether ncRNAs can be used as new biomarkers or therapies. In this review, we focus on recent studies of ncRNAs including microRNAs (miRNAs), long ncRNAs (lncRNAs), circle RNAs (circRNAs), PIWI interacting RNAs (piRNAs), and tRNA in different types of cancer and explore the application of these ncRNAs in the development of cancer and the identification of relevant therapeutic targets and tumor biomarkers. Graphical abstract drawn by Fidraw.

Long non‑coding RNAs, lipid metabolism and cancer (Review)

Cancer has emerged as the most common cause of death in China. The change in lipid metabolism has been confirmed to have a role in several tumor types, such as esophageal, gastric, colorectal and liver cancer. Cancer cells use lipid metabolism for energy and then rapidly proliferate, invade and migrate. The main pathway by which cancer cell lipid metabolism influences cancer progression is increased fatty acid synthesis. Long non-coding (lnc)RNAs are important ncRNAs that were indicated to have significant roles in the development of human tumors. They are considered potential tumor biomarkers. Increased lipid synthesis or uptake due to deregulation of lncRNAs contributes to rapid tumor growth. In the present review, current studies on the relationship between lncRNAs, lipid metabolism and the occurrence and development of tumors were collated and summarized, and their mechanism of action was discussed. The review is expected to provide a theoretical basis for tumor treatment and prognosis evaluation based on the effective regulation of lncRNAs and lipid metabolism.

Roles of long non-coding RNAs in digestive tract cancer and their clinical application

Long non-coding RNAs (lncRNAs) are strongly related to the occurrence and development of digestive tract cancer in human. Firstly, lncRNAs target and regulate the expression of downstream cancer genes to affect the growth, metastasis, apoptosis, metabolism and immune escape of cancer cells. Secondly, lncRNAs are considered to be important regulating factors for lipid metabolism in cancer, which is related to signaling pathways of adipogenesis and involved in the occurrence and development of digestive tract cancer. Finally, lncRNAs have application value in the diagnosis and treatment of digestive tract cancer. For example, lncRNAMALAT1 has been reported as a target for diagnosis and treatment of hepatocellular carcinoma. This article reviews current progress on the regulatory role of lncRNAs in digestive tract cancer, to provide references for the research and clinical application in the prevention and treatment of digestive tract cancer.

Novel risk model based on angiogenesis-related lncRNAs for prognosis prediction of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death due to early metastasis or recurrence. Tumor angiogenesis plays an essential role in the tumorigenesis of HCC. Accumulated studies have validated the crucial role of lncRNAs in tumor angiogenesis. Here, we established an angiogenesis-related multi-lncRNAs risk model based on the machine learning for HCC prognosis prediction. Firstly, a total of 348 differential expression angiogenesis-related lncRNAs were identified by correlation analysis. Then, 20 of these lncRNAs were selected through univariate cox analysis and used for in-depth study of machine learning. After 1,000 random sampling cycles calculating by random forest algorithm, four lncRNAs were found to be highly associated with HCC prognosis, namely LUCAT1, AC010761.1, AC006504.7 and MIR210HG. Subsequently, the results from both the training and validation sets revealed that the four lncRNAs-based risk model was suitable for predicting HCC recurrence. Moreover, the infiltration of macrophages and CD8 T cells were shown to be closely associated with risk score and promotion of immune escape. The reliability of this model was validated by exploring the biological functions of lncRNA MIR210HG in HCC cells. The results showed that MIR210HG silence inhibited HCC growth and migration through upregulating PFKFB4 and SPAG4. Taken together, this angiogenesis-related risk model could serve as a reliable and promising tool to predict the prognosis of HCC.

Cell Cycle-Related lncRNAs as Innovative Targets to Advance Cancer Management

Long non-coding RNAs (lncRNAs) are non-coding RNAs (ncRNAs) longer than 200nt. They have complex biological functions and take part in multiple fundamental biological processes, such as cell proliferation, differentiation, survival and apoptosis. Recent studies suggest that lncRNAs modulate critical regulatory proteins involved in cancer cell cycle, such as cyclin, cell cycle protein-dependent kinases (CDK) and cell cycle protein-dependent kinase inhibitors (CKI) through different mechanisms. To clarify the role of lncRNAs in the regulation of cell cycle will provide new ideas for design of antitumor therapies which intervene with the cell cycle progression. In this paper, we review the recent studies about the controlling of lncRNAs on cell cycle related proteins such as cyclin, CDK and CKI in different cancers. We further outline the different mechanisms involved in this regulation and describe the emerging role of cell cycle-related lncRNAs in cancer diagnosis and therapy.

Molecular Signature of Long Non-Coding RNA Associated with Areca Nut-Induced Head and Neck Cancer

The areca nut is a high-risk carcinogen for head and neck cancer (HNC) patients in Southeast Asia. The underlying molecular mechanism of areca nut-induced HNC remains unclear, especially regarding the role of long non-coding RNA (lncRNA). This study employed a systemic strategy to identify lncRNA signatures related to areca nut-induced HNC. In total, 84 cancer-related lncRNAs were identified. Using a PCR array method, 28 lncRNAs were identified as being dysregulated in HNC cells treated with areca nut (17 upregulated and 11 downregulated). Using bioinformatics analysis of The Cancer Genome Atlas Head-Neck Squamous Cell Carcinoma (TCGA-HNSC) dataset, 45 lncRNAs were differentially expressed in tumor tissues from HNC patients (39 over- and 6 under-expressions). The integrated evaluation showed 10 lncRNAs dysregulated by the areca nut and altered expression in patients, suggesting that these panel molecules participate in areca nut-induced HNC. Five oncogenic (LUCAT1, MIR31HG, UCA1, HIF1A-AS2, and SUMO1P3) and tumor-suppressive (LINC00312) lncRNAs were independently validated, and three key molecules were further examined. Pathway prediction revealed that LUCAT1, UCA1, and MIR31HG modulate multiple oncogenic mechanisms, including stress response and cellular motility. Clinical assessment showed that these lncRNAs exhibited biomarker potentials in diagnosis (area under the curve = 0.815 for LUCAT1) and a worse prognosis (both p < 0.05, survival analysis). Cellular studies further demonstrated that MIR31HG facilitates areca nut-induced cancer progression, as silencing this molecule attenuated arecoline-induced invasion ability in HNC cells. This study identified lncRNA signatures that play a role in areca nut-induced HNC. These molecules may be further applied in risk assessment, diagnosis, prognosis, and therapeutics for areca nut-associated malignancies.

Long non-coding RNA LUCAT1 regulates the RAS pathway to promote the proliferation and invasion of malignant glioma cells through ABCB1

Long non-coding RNAs (lncRNAs) are closely related to the occurrence and development of tumors and have gradually become a hot topic in the field of glioma research in recent years. In this study, the role of lung cancer associated transcript 1 (lncRNA LUCAT 1) in glioma occurrence and development, as well as its possible regulatory mechanism, was explored. We utilized the gene chip technology in the preliminary experiment, and based on the experiment results, selected LUCAT1（NONHSAT102745）, which was significantly upregulated in glioma, and ATP-binding cassette Subfamily B member l (ABCB1), which was significantly down-regulated in co-expression analysis, for study. Next, the expression of LUCAT1 and ABCB1 in cells and tissues was immediately evaluated. Subsequently, the cells were transfected with scrambled siRNA, LUCAT1-siRNA/ABCB 1-siRNA, or overexpressed LUCAT1/ABCB1 plasmid + RAS signaling pathway inhibitor-farnesylthiosalicylic acid (FTS). By comparing with the normal combination negative control group, the cell proliferation and invasion ability were evaluated. Finally, subcutaneous tumor formation experiments in the nude mice confirmed the association between LUCAT1 and ABCB1 and RAS signaling pathways. The expression of LUCAT 1 was up-regulated with an increase in WHO grade, and the lncRNA-mRNA co-expression analysis showed that the expression of ABCB1 was low. LUCAT 1 gene knockout reduced the mRNA and protein levels of Ras signaling pathway related factors (Ras, Raf-1, p-AKT, and p-ERK) as regulating ABCB1 expression and inhibiting the ability of tumor in proliferation and invasion no matter in vitro or in vivo. For overexpressing of LUCAT 1, the opposite was true. After we knocked out ABCB1, the LUCAT1 expression was reversely regulated while the level of RAS signaling pathway related factors increased, and the ability of tumors in proliferation and invasion was enhanced. The abnormal LUCAT1 expression affected the biological behaviors of glioma cells, such as proliferation, invasion, etc. by regulating ABCB1 and promoting the activation of the RAS signaling pathway. This provided a new drug target and therapeutic approach for gene therapy of glioma, which is expected to significantly improve the prognosis of relevant patients.

Biomarkers of gastric cancer: current advancement

Gastric cancer (GC) is one of the most prevalent malignant types worldwide, especially in East Asia. Due to its frequently advanced stage at diagnosis, the mortality from GC is high and the prognosis is still unsatisfactory. Thus, early detection using effective screening approaches is vital to decrease the morbidity and mortality of GC. Interestingly, biomarkers can be used for diagnosis, prediction of sensitivity to treatment, and prognosis in GC. The potential biomarkers detectable in liquid biopsies such as circulating tumor cells (CTCs), long non-coding RNAs (lncRNAs), cell-free DNA (cfDNA), microRNAs, and exosomes reveal numerous information regarding the early prediction and the outcomes for GC patients. Additionally, using the novel serum biomarkers has opened up new opportunities for diagnosing and monitoring patients with GC. This review mainly summarizes the novel progress and approaches in GC biomarkers, which could be potentially used for early diagnosis and therapy monitoring. Meanwhile, we also discussed the advantages, disadvantages, and future perspectives of GC biomarkers.

Construction of a Prognostic Model for Hypoxia-Related LncRNAs and Prediction of the Immune Landscape in the Digestive System Pan-Cancer

Digestive system pan-cancer is a general term for digestive system tumors including colorectal carcinoma (CRC), esophageal carcinoma (ESCA), stomach adenocarcinoma (STAD), and liver hepatocellular carcinoma (LIHC). Since the anatomical location, function and metabolism are closely related, there may be similarities in development and progression of these tumors. Hypoxia is the consequence of an imbalance between oxygen demand and supply, and intracellular hypoxia is associated with malignant progression, treatment resistance, and poor prognosis in tumors. Therefore, an urgent and challenging task is to investigate the molecular mechanisms associated with hypoxia in digestive system pan-cancer for the prognosis and treatment of digestive tract tumors. In this study, we identified 18 hypoxia-related lncRNAs (HRlncRNAs) by co-expression analysis between hypoxia genes and lncRNAs from digestive system pan-cancer. Six HRlncRNAs were then obtained using lasso regression and multivariate cox analysis to construct a prognostic model. Next, the Akaike information criterion (AIC) values for 3-year receiver operating curve (ROC) were counted to determine the cut-off point and establish an optimal model to distinguish between high- or low-risk groups among patients with digestive system pan-cancer. To evaluate the stability of the prognosis model, we validated it in terms of survival outcomes, clinicopathological stage, tumor-infiltrating immune cells, immune checkpoint inhibitors (ICIs) and anticancer drugs sensitivity. The results suggested that high- risk group had a worse prognosis and a more positive association with tumor-infiltrating immune cells such as B cells, cancer-associated fibroblasts, endothelial cells, monocytes, macrophages and bone marrow dendritic cells in digestive system pan-cancer. Immune checkpoint inhibitors (ICIs) related biomarkers discovered that high-risk group was positively correlated with high expression of HAVCR2 in digestive system pan-cancer. The anticancer drugs sensitivity analysis showed that the high-risk group was associated with the lower half-inhibitory centration (IC50) of Imatinib in digestive system pan-cancer. In conclusion, the prognostic model of HRlncRNAs showed a promising clinical prediction value and may provide a useful reference for the diagnosis and treatment of the digestive system tumors.

lncRNA LUCAT1/ELAVL1/LIN28B/SOX2 Positive Feedback Loop Promotes Cell Stemness in Triple-Negative Breast Cancer

Background. Triple-negative breast cancer (TNBC), as a subtype of breast cancer (BC), features an aggressive nature. Long noncoding RNAs (lncRNAs) are proved to get involved in the processes of cancers. lncRNA lung cancer associated transcript 1 (LUCAT1) has been reported in multiple cancers. The role of LUCAT1 in TNBC and its latent regulatory mechanism were investigated. Methods. RT-qPCR was performed to examine LUCAT1 expression. Functional experiments were implemented to disclose the role of LUCAT1 in TNBC. The underlying regulatory mechanism of LUCAT1 in TNBC was explored by chromatin immunoprecipitation (ChIP), RNA-binding protein immunoprecipitation (RIP), luciferase reporter, and RNA pull-down assays. Results. LUCAT1 is significantly overexpressed in TNBC cells. LUCAT1 interference impedes cell stemness in TNBC cells. SRY-box transcription factor 2 (SOX2) is an active transcription factor of LUCAT1. LUCAT1 recruits ELAV-like RNA binding protein 1 (ELAVL1) protein to stabilize lin-28 homolog B (LIN28B) mRNA, thereby further modulating SOX2 expression, which forms a positive feedback loop. Conclusion. The lncRNA LUCAT1/ELAVL1/LIN28B/SOX2 positive feedback loop promotes cell stemness in TNBC. The exploration of the mechanisms underlying TNBC stemness might be beneficial to TNBC treatment.

Circular RNA circ_0004277 Inhibits Acute Myeloid Leukemia Progression Through MicroRNA-134-5p / Single stranded DNA binding protein 2

Circular RNAs (circRNAs) are crucial non-coding RNAs in the process of tumorigenesis. Nevertheless, the biological function of circ_0004277 in acute myeloid leukemia (AML) is blurred. Microarray data of circRNAs were utilized to evaluate circRNAs’ differential expression in AML. Quantitative real-time polymerase chain reaction (qRT-PCR) was executed to determine circ_0004277 and microRNA-134-5p (miR-134-5p) expression levels. The growth, migration and invasion of AML cells were tested by the cell counting kit-8 and Transwell experiment. Dual-luciferase reporter gene experiment, RNA immunoprecipitation (RIP) experiment and RNA pull-down experiment were executed to determine the targeting relationship between circ_0004277 and miR-134-5p. Western blot assay was used to detect single stranded DNA binding protein 2 (SSBP2) expression. We observed that circ_0004277 was down-regulated in AML, while miR-134-5p was up-regulated. Functionally, circ_0004277 overexpression or inhibition of miR-134-5p remarkably suppressed AML cell viability, migration and invasion. Furthermore, miR-134-5p served as a direct downstream target of circ_0004277 and SSBP2 was identified as a target of miR-134-5p. Compensation experiments showed that miR-134-5p mimics abolished the biological function of circ_0004277 on malignant phenotypes of AML cells. Collectively, circ_0004277 impedes AML development by adsorbing miR-134-5p and up-regulating SSBP2.

Circular RNA ZNF609 promotes laryngeal squamous cell carcinoma progression by upregulating epidermal growth factor receptor via sponging microRNA-134-5p

Emerging evidence has revealed that aberrantly expressed circular RNAs (circRNAs) play vital roles in tumorigenesis and progression of diverse human malignancies. CircZNF609 was found to be involved in hepatocellular carcinoma, but the role and underlying mechanism of circZNF609 in laryngeal squamous cell carcinoma (LSCC) remain unclear. This study aimed to explore the molecular mechanism of circZNF609 in LSCC. qRT-qPCR was performed to detect the expression of circZNF609 and microRNA-134-5p (miR-134-5p) in LSCC. Colony formation assay, CCK-8 assay, BrdU incorporation assay, clone formation assay, transwell invasion assay and Western blot analysis were performed to evaluate LSCC cell proliferation, as well as the expression of proliferating cell nuclear antigen (PCNA) and MMP-2. Luciferase reporter assay, target gene prediction and screening were used to validate downstream target genes of circZNF609 and miR-134-5p. EGFR expression was detected by Western blot analysis and RT-qPCR. Nude mice were used to detect tumor changes. CircZNF609 was upregulated in LSCC and associated with poor survival of LSCC patients. Knockdown of circZNF609 inhibited LSCC proliferation, invasion and the expression of PCNA and matrix matalloproteinases-2 (MMP-2). CircZNF609 can regulate miR-134-5p to upregulate epidermal growth factor receptor (EGFR). In addition, knockdown of EGFR or overexpression of miR-134-5p could reverse the tumor-promoting effects of circZNF609 in LSCC. In LSCC tissues, circZNF609 was negatively correlated with miR-134-5p and positively correlated with EGFR. CircZNF609 promotes the progression of LSCC via the miR-134-5p/EGFR axis, which might be the therapeutic target of LSCC.

Autophagy and gastrointestinal cancers: the behind the scenes role of long non-coding RNAs in initiation, progression, and treatment resistance

Gastrointestinal (GI) cancers comprise a heterogeneous group of complex disorders that affect different organs, including esophagus, stomach, gallbladder, liver, biliary tract, pancreas, small intestine, colon, rectum, and anus. Recently, an explosion in nucleic acid-based technologies has led to the discovery of long non-coding RNAs (lncRNAs) that have been found to possess unique regulatory functions. This class of RNAs is >200 nucleotides in length, and is characterized by their lack of protein coding. LncRNAs exert regulatory effects in GI cancer development by affecting different functions such as the proliferation and metastasis of cancer cells, apoptosis, glycolysis and angiogenesis. Over the past few decades, considerable evidence has revealed the important role of autophagy in both GI cancer progression and suppression. In addition, recent studies have confirmed a significant correlation between lncRNAs and the regulation of autophagy. In this review, we summarize how lncRNAs play a behind the scenes role in the pathogenesis of GI cancers through regulation of autophagy.

An Autophagy-Related Long Non-Coding RNA Prognostic Signature for Patients with Lung Squamous Carcinoma Based on Bioinformatics Analysis

Purpose

Lung cancer is the most common and deadly cancer type affecting humans. Although huge progress has been made on early diagnosis and precision treatment, the overall 5 year survival rate remains low. In this study, we constructed an autophagy-related long non-coding RNA (lncRNA) prognostic signature for guiding clinical practice.

Methods

From The Cancer Genome Atlas, we retrieved mRNA and lncRNA expression matrices of patients with lung squamous carcinoma. We then established a prognostic risk model using Lasso regression and multivariate Cox regression. The model generated a risk score to differentiate high- and low-risk groups. An ROC curve and nomogram were used to visualize the predictive ability of the current signatures. Finally, we used Gene Set Enrichment Analysis to determine gene ontology and pathway enrichment.

Results

After screening 1248 autophagy-related lncRNAs, we selected seven lncRNAs (LUCAT1, AC022150.2, AL035425.3, AC138976.2, AC106786.1, GPRC5D-AS1 and AP006545.2) for our signature. Univariate (hazard ratio [HR] = 2.147, 95% confidence interval [CI]: 1.681–2.743, P < 0.001) and multivariate (HR = 2.096, 95% CI: 1.652–2.658, P < 0.001) Cox regression analyses revealed that the risk score is an independent predictive factor for LUSC patients. Further, areas under the receiver operating characteristic curve were 0.622, 0.699, and 0.721, respectively, for the 1 year, 3 year, and 5 year risk scores—indicating a reliable model. Selected lncRNAs were primarily enriched in autophagy, metabolism, MAPK pathway, and JAK/STAT pathway. Further drug sensitivity analysis revealed that low-risk patients were more sensitive to Cisplatin, Docetaxel, Vinblastine, and Vinorelbine. Finally, a multi-omics analysis found that lncRNA-linked proteins IKBKB and SQSTM1 were expressed at low levels and significantly correlated in tumor samples, compared with normal tissue.

Conclusion

Our prognostic model successfully predicted patient prognosis in lung cancer.

FOXD1-AS1 promotes malignant behaviours of prostate cancer cells via the miR-3167/YWHAZ axis

Herein, the effect of long noncoding RNA forkhead box D1 antisense RNA 1 (FOXD1-AS1) on malignant phenotypes of prostate cancer (PCa) cells was investigated. FOXD1-AS1 presented high expression in PCa cells according to the results of RT-qPCR. As shown by cell counting kit-8 assays, colony formation assays, wound-healing assays, Transwell assays and flow cytometry analyses, silenced FOXD1-AS1 suppressed PCa cell viability, proliferation, migration and invasion and enhanced cell apoptosis. Additionally, FOXD1-AS1 was primarily localised in cytoplasm of PCa cells. RNA immunoprecipitation assays and luciferase reporter assays revealed that FOXD1-AS1 interacted with miR-3167 in PCa cells. MiR-3167 functioned as an anti-oncogene in PCa and miR-3167 overexpression suppressed cell proliferation while promoted cell apoptosis. Moreover, the downstream target of miR-3167 is mRNA YWHAZ. FOXD1-AS1 elevated the expression of YWHAZ by binding with miR-3167. The suppressive effect of miR-3167 on YWHAZ expression was reversed by FOXD1-AS1 overexpression. Furthermore, overexpressed YWHAZ reversed the suppressive effect of FOXD1-AS1 deficiency on malignant behaviours of PCa cells. Overall, FOXD1-AS1 facilitates malignant phenotypes of PCa cells by up-regulating YWHAZ via miR-3167. The study first reveals the molecular mechanism of FOXD1-AS1 in PCa, suggesting that FOXD1-AS1 and its downstream molecules might be prognostic biomarkers before medical treatment.

Concomitant and decoupled effects of cigarette smoke and SCAL1 upregulation on oncogenic phenotypes and ROS detoxification in lung adenocarcinoma cells

Lung cancer is the leading cause of cancer deaths worldwide, with smoking as its primary predisposing factor. Although carcinogens in cigarettes are known to cause oncogenic DNA alterations, analyses of patient cohorts revealed heterogeneous genetic aberrations with no clear driver mutations. The contribution of noncoding RNAs (ncRNAs) in the pathogenesis of lung cancer has since been demonstrated. Their dysregulation has been linked to cancer initiation and progression. A novel long noncoding RNA (lncRNA) called smoke and cancer-associated lncRNA 1 (SCAL1) was recently found upregulated in smoke-exposed adenocarcinomic alveolar epithelial cells. The present study characterized the phenotypic consequences of SCAL1 overexpression and knockdown using A549 cells as model system, with or without prior exposure to cigarette smoke extract (CSE). Increase in SCAL1 levels either by CSE treatment or SCAL1 overexpression led to increased cell migration, extensive cytoskeletal remodeling, and resistance to apoptosis. Further, SCAL1 levels were negatively correlated with intracellular levels of reactive oxygen species (ROS). In contrast, SCAL1 knockdown showed converse results for these assays. These results confirm the oncogenic function of SCAL1 and its role as a CSE-activated lncRNA that mediates ROS detoxification in A549 cells, thereby allowing them to develop resistance to and survive smoke-induced toxicity.

Exosome miR-134-5p restrains breast cancer progression via regulating PI3K/AKT pathway by targeting ARHGAP1

AIM

Exosomes has been shown to be involved in the regulation of cancer progression. However, the role of exosome miR-134-5p in breast cancer (BC) progression is unclear.

METHODS

Exosomes were extracted from BC cells (MCF-7 and MDA-MB-231) using differential centrifugation and were observed by transmission electron microscope (TEM). The protein levels of exosome markers, apoptosis markers, Rho GTPase activating protein 1 (ARHGAP1, an important oncogene in BC) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) markers were detected by western blot (WB) assay. Quantitative real-time PCR was used to measure the expression levels of miR-134-5p and ARHGAP1. Cell cycle and apoptosis, colony number, viability, migration, and invasion were determined by flow cytometry, colony formation assay, MTT assay, and transwell assay, respectively. The interaction between miR-134-5p and ARHGAP1 was confirmed using a dual-luciferase reporter assay. Xenograft models were constructed to verify the role of exosome miR-134-5p in BC tumor growth in vivo.

RESULTS

MiR-134-5p was lowly expressed in BC cells and in the exosomes of BC cells. Overexpressed exosome miR-134-5p suppressed the proliferation, migration, invasion, and promoted the apoptosis of BC cells. ARHGAP1 was a target of miR-134-5p, and its silencing could inhibit BC progression. In addition, ARHGAP1 overexpression could reverse the negative regulation of miR-134-5p on BC progression. MiR-134-5p could target ARHGAP1 to inhibit the activity of PI3K/AKT pathway. Exosome miR-134-5p overexpression could suppress BC tumor growth via targeting ARHGAP1 in vivo.

CONCLUSION

Exosome miR-134-5p restrained BC progression through regulating ARHGAP1/PI3K/AKT signaling pathway, suggesting that miR-134-5p might be a therapeutic target for BC.

Expression of long non-coding RNA LUCAT1 in patients with chronic obstructive pulmonary disease and its potential functions in regulating cigarette smoke extract-induced 16HBE cell proliferation and apoptosis

BACKGROUND

Chronic obstructive pulmonary disease (COPD), characterized by persistent airflow limitation, was a disease mediated by a combination of inflammatory factors, immune cells, and immune mediators. COPD was an inflammatory and autoimmune disease involving T-lymphocytes triggered by cigarette smoke and other factors that progressively affected the bronchi, lung parenchyma, and pulmonary blood vessels. LncRNAs were reported to be implicated in COPD pathogenesis and development.

METHODS

Non-smokers, smokers (non-COPD), and COPD patients were randomly selected in an established COPD surveillance cohort. Demographic and clinical information of all subjects were collected. Pulmonary function was measured by post-bronchodilator testing. qRT-PCR and ELISA assays were performed to detect the expression levels of lncRNA LUCAT1, miR-181a-5p, and inflammatory cytokines. An in vitro exposure model was constructed using cigarette smoke extract (CSE)-induced human bronchial epithelial (16HBE) cells. The dual-luciferase reporter and RNA pull-down assays were used to detect the binding relationship between lncRNA LUCAT1 and miR-181a-5p; meanwhile, Spearman's correlation assay was used to verify the correlation between lncRNA LUCAT1 and miR-181a-5p. Afterward, the lncRNA LUCAT1 silencing plasmid was constructed and co-transfected with a miR-181a-5p inhibitor to evaluate the effects on CSE-induced 16HBE cell proliferation and apoptosis. Finally, a Western blot assay was utilized to determine the mechanism of lncRNA LUCAT1/miR-181a-5p/Wnt/β-catenin axis in COPD.

RESULTS

LncRNA LUCAT1 was upregulated in the serums of COPD patients. Correlation analysis further confirmed the strong correlation between LUCAT1 expression and inflammatory cytokines IL-1β, IL-6, and TNF-α. Receiver operating characteristic (ROC) analysis verified the potential of LUCAT1 in COPD diagnosis. After treatment with CSE, LUCAT1 was significantly increased while its target miR-181a-5p was decreased in 16HBE cells. Cell proliferation and apoptosis assays showed that LUCAT1 silencing alleviated CSE's effects on 16HBE cell proliferation and apoptosis. Mechanically, rescue assays demonstrated that miR-181a-5p inhibition could partially counteract the impact of LUCAT1 on COPD progression through the Wnt/β-catenin pathway.

CONCLUSIONS

LncRNA LUCAT1 may be a valuable indicator for differentiating COPD. Moreover, LncRNA LUCAT1/miR-181-5p/Wnt/β-catenin axis behaved as a critical role in COPD development, shedding new sights for clinical treatment.

Long Noncoding RNA HCG11 Acts as a Tumor Suppressor in Gastric Cancer by Regulating miR-942-5p/BRMS1 Axis

The functions of long noncoding RNAs (lncRNAs) have been widely investigated in human cancers, including gastric cancer (GC). The purpose of this study was to elucidate the role of lncRNA HCG11 in GC. In this study, mRNA and protein expressions were detected by quantitative real-time polymerase chain reaction assays (RT-qPCR) and Western blot analysis. The proliferation ability of GC cells was examined by (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyl Tetrazolium Bromide) MTT assays. The invasion and migration abilities of GC cells were evaluated by Transwell assays. The binding sites between miR-942-5p and HCG11/BRMS1 were confirmed by dual-luciferase reporter assays. Results showed that LncRNA HCG11 was downregulated in GC cells. Functionally, overexpression of HCG11 inhibited GC cell proliferation, migration, and invasion. In addition, lncRNA HCG11 was found to act as a molecular sponge of miR-942-5p. Furthermore, miR-942-5p promoted GC progression by suppressing lncRNA HCG11 expression. Besides that, BRMS1 was confirmed as a direct target of miR-942-5p. More importantly, breast cancer metastasis suppressor 1 (BRMS1) inhibited GC progression by upregulating lncRNA HCG11 and downregulating miR-942-5p. In conclusion, LncRNA HCG11 inhibited cell proliferation, migration, and invasion in GC by sponging miR-942-5p and upregulating BRMS1.

Perspectives on Epigenetics Alterations Associated with Smoking and Vaping

Epigenetic alterations, including DNA methylation, microRNA, and long noncoding RNA, play important roles in the pathogenesis of numerous respiratory health conditions and diseases. Exposure to tobacco smoking has been found to be associated with epigenetic changes in the respiratory tract. Marketed as a less harmful alternative to combustible cigarettes, electronic cigarette (e-cigarette) has rapidly gained popularity in recent years, especially among youth and young adults. Accumulative evidence from both animal and human studies has shown that e-cigarette use (vaping) is also linked to similar respiratory health conditions as observed with cigarette smoking, including wheezing, asthma, and COPD. This review aims to provide an overview of current studies on associations of smoking and vaping with epigenetic alterations in respiratory cells and provide future research directions in epigenetic studies related to vaping.

NR2F2-AS1 accelerates cell proliferation through regulating miR-4429/MBD1 axis in cervical cancer

Cervical cancer is one of the most frequent malignant tumors in female. Increasing studies have demonstrated that long noncoding RNAs (lncRNAs) play a key role in the development of multiple cancers. Although some studies have confirmed that lncRNA NR2F2 antisense RNA 1 (NR2F2-AS1) is a pro-cancer gene in many cancers, the molecular mechanism of NR2F2-AS1 in cervical cancer has not been completely elucidated. In the present study, our results revealed that NR2F2-AS1 expression was up-regulated in cervical cancer tissues and cells, notably in patients with advanced cervical cancer. NR2F2-AS1 accelerated progression of cervical cancer by facilitating cell proliferation, migration, invasion, and EMT process, but inhibiting cell apoptosis. Moreover, NR2F2-AS1 acted as a molecular sponge of miR-4429 and methyl-CpG-binding domain protein 1 (MBD1) was a downstream target of miR-4429 in cervical cancer. Furthermore, there was a negative correlation between miR-4429 expression and NR2F2-AS1 or MBD1 expression in tumor tissues. Rescue experiments confirmed that MBD1 overexpression partly rescued NR2F2-AS1 knockdown-mediated inhibition of progression in cervical cancer. To sum up, these results suggested the potential mechanism of NR2F2-AS1 in cervical cancer and revealed that NR2F2-AS1 exerted its carcinogenic effect via regulating miR-4429/MBD1 axis, indicating a promising insight into the therapeutic target of cervical cancer.

MiR-133b inhibits colorectal cancer metastasis via lncRNA-LUCAT1

Aim: Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Metastasis is the leading cause of poor prognosis of CRC patients, warranting further study of the molecular mechanism of metastasis in CRC and identification of new therapeutic targets. MiR-133b has been proven to play an important role in tumorigenesis by directly targeting coding genes. However, whether miR-133b can regulate tumorigenesis via long noncoding RNA (lncRNA) remains unclear. Methods: We systematically analyzed the expression level and correlation of miR-133b and LUCAT1 in cancer tissues and adjacent tissues from 30 patients with CRC. The effects of miR-133b and LUCAT1 on the invasive ability of CRC cells were detected by a transwell assay. The relationship between miR-133b and LUCAT1 was investigated by cells transfection experiments, rescue experiments and luciferase reporter assays. The binding of LUCAT1 and EZH2 was detected by RNA immunoprecipitation assay. Results: MiR-133b was expressed at low levels in CRC tissues, and LUCAT1 was highly expressed, with an inverse correlation between them. LUCAT1 promoted the migration and invasion of HCT116 and SW620 cells. Overexpression of LUCAT1 attenuated the inhibition of cell migration and invasion induced by miR-133b. However, the dual luciferase assay showed that miR-133b did not directly target LUCAT1. Conclusion: MiR-133b affects CRC metastasis via the LUCAT1/EZH2 complex. MiR-133b and LUCAT1 may be potential targets for antimetastasis therapy in CRC.

LINC01278 is Highly Expressed in Osteosarcoma and Participates in the Development of Tumors by Mediating the miR-134-5p/KRAS Axis

Purpose

There is increasing evidence that non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), produce a critical regulatory effect on osteosarcoma (OS). LINC01278, as a newly discovered lncRNA, is found to be highly expressed in OS, but its related mechanism remains unclear. This research, therefore, is designed to study the mechanism of LINC01278 in OS and to find potential targets for clinical use.

Methods

qRT-PCR was applied to determine the relative expression of LINC01278 and analyze its diagnostic value in OS. CCK-8, Transwell and flow cytometry were utilized for the determination of cell proliferation, migration/invasion, and apoptosis. RIP and RNA pull-down experiments were used to verify the targeted binding effect of miR-134-5p and LINC01278. The relationship between miR-134-5p and LINC01278 or KRAS was analyzed using dual luciferase reporter gene. The effects of LINC01278 on tumor growth in nude mice was analyzed by in vivo experiment.

Results

qRT-PCR showed that LINC01278 increased in OS tissues and serum, indicating poor prognosis. In addition, LINC01278 was also of high value for OS diagnosis. Functional experiments showed that LINC01278 inhibited KRAS-mediated OS cell proliferation and metastasis through miR-134-5p. Finally, the results of an in vivo animal model indicated that LINC01278 promoted OS growth.

Conclusion

LINC01278 is expressed highly in OS, and patients with high LINC01278 expression have poor prognosis. Moreover, LINC01278 can suppress the proliferation and apoptosis of OS cells through mediating miR-134-5p/KRAS axis, which is expected to become a potential therapeutic target for OS.

Knockdown of the Long Noncoding RNA LUCAT1 Inhibits High-Glucose-Induced Epithelial-Mesenchymal Transition through the miR-199a-5p-ZEB1 Axis in Human Renal Tubular Epithelial Cells

Renal fibrosis, the leading cause of end-stage renal disease and in which epithelial-mesenchymal transition (EMT) plays a central role, has a complex pathogenesis that is not fully understood. Therefore, we investigated the role of the long noncoding RNA LUCAT1 in the EMT of renal tubular epithelial cells under high-glucose (HG) conditions and the underlying mechanism involved. In this study, we established HG and normal glucose groups of HK-2 cells by treating HK-2 cells 30.0 or 5.5 mmol/L glucose, respectively. To investigate the roles of LUCAT1 and miR-199a-5p in HG-induced EMT, we transfected the HG group with negative control small interfering RNA (siRNA), siRNA targeting LUCAT1, negative control microRNA, or an miR-199a-5p mimic. The results of the quantitative reverse transcription PCR indicated that the LUCAT1 level in the HG group was increased, whereas the miR-199a-5p level was decreased. The EMT in the cells was induced by treatment with HG but was weakened by LUCAT1 knockdown or miR-199a-5p overexpression, which both also inhibited the HG-induced phosphorylation of SMAD3. Moreover, LUCAT1 and ZEB1 mRNA comprised the same microRNA response elements of miR-199a-5p. LUCAT1 knockdown had no effect on the miR-199a-5p level but decreased the HG-induced upregulation of ZEB1. In conclusion, HG conditions induced the upregulation of LUCAT1, and LUCAT1 knockdown inhibited the EMT in HG-treated HK-2 cells. LUCAT1 likely promotes HG-induced EMT through ZEB1 by sponging miR-199a-5p.

Downregulation of lncRNA HCP5 has inhibitory effects on gastric cancer cells by regulating DDX21 expression

LncRNA HCP5 has been confirmed to play crucial roles in many types of cancers. However, the role of lncRNA HCP5 in regulating the occurrence and development of gastric cancer (GC) remains unknown. In the current study, we aimed to investigate the precise effects of lncRNA HCP5 on cell proliferation, migration and invasion and molecular mechanisms in gastric cancer. Using RT-qPCR analysis, we found that lncRNA HCP5 was differentially expressed in GC cell lines. CCK-8, wound healing and transwell assay indicated that the proliferation, migration and invasion of gastric cancer cells were inhibited by downregulation of lncRNA HCP5 and lncRNA HCP5 overexpression exhibited the opposite effects in gastric cancer cells. Mechanistically, RNA binding protein immunoprecipitation and dual luciferase reporter assay confirmed the interaction between lncRNA HCP5 and DDX21. The effects of lncRNA HCP5 overexpression the proliferation, migration and invasion of GC cells were partly rescued by DDX21 silencing. Taken together, downregulation of lncRNA HCP5 exerted inhibitory effects on GC cell proliferation, migration and invasion through modulation of DDX21 expression, demonstrating the function of lncRNA HCP5 and DDX21 in GC progression.

Role of lncRNA LUCAT1 in cancer

Long non-coding RNAs (lncRNAs) are RNA molecules with a transcript length of more than 200 nt and lack a protein-coding ability. They regulate gene expression by interacting with protein, RNA, and DNA. Their function is closely related to their subcellular localization. In the nucleus, lncRNAs regulate gene expression at the epigenetic and transcriptional levels, and in the cytoplasm, they regulate gene expression at the post-transcriptional and translational levels. Abnormalities in lncRNAs have been confirmed to exhibit tumor suppressor or carcinogenic effects and play an important role in the development of tumors. In particular, the lung cancer-related transcript 1 (LUCAT1) located in the antisense strand of the q14.3 region of chromosome 5 was first discovered in smoking-related lung cancer. Increasing evidence have showed that LUCAT1 is involved in breast cancer, ovarian cancer, thyroid cancer, renal cell carcinoma. It is highly expressed in liver cancer and other malignant tumors and has been confirmed to be induce various malignant tumors. It regulates tumor proliferation, invasion, and migration via various mechanisms and is related to the clinicopathological characteristics of tumor patients. Thus, LUCAT1 is a potential prognostic biological marker and therapeutic target for cancer. This article reviews its expression, function, and molecular mechanism in various malignant tumors.

LUCAT1 Epigenetically Downregulates the Tumor Suppressor Genes CXXC4 and SFRP2 in Gastric Cancer

PURPOSE

The mechanisms of Wnt/β-catenin pathway signaling and abnormal expression of tumor suppressor genes is not well known in gastric cancer (GC). Long non-coding RNA (lncRNA) has recently been identified as a possible link therein. In this study, we investigated the role of lung cancer associated transcript 1 (LUCAT1) in GC.

MATERIALS AND METHODS

The expression of LUCAT1 in GC cell lines and 100 tissue samples was examined by qRT-PCR. Two different siRNAs were used for knockdown of LUCAT1 expression. Cell viability was assessed by MTT assay. To analyze metastasis, scratch wound-healing assay, a Matrigel invasion assay, and colony formation assay were performed. Apoptosis was analyzed by PI/Annexin-V staining. To check the methylation status in tumor suppressor genes, methylation-specific PCR was carried out. Western blot was performed to detect epithelial-mesenchymal transition and apoptosis markers upon silencing of LUCAT1 (siLUCAT1).

RESULTS

LUCAT1 expression in GC cell lines and tissues was significantly elevated, compared to that in normal gastric cells and adjacent non-tumor tissues (p<0.001). Two different siRNAs for LUCAT1 reduced cell proliferation, invasion, and migration, compared to siCT (p<0.05), and these reductions were restored by pcDNA-LUCAT1 (p<0.05). siLUCAT1 elicited upregulation of the expression of CXXC4 and SFRP2. The expression of H3K27me3 was reduced by siLUCAT1, and this reduction was correlated with methylation of CXXC4 and SFRP2. Inhibition of LUCAT1 up-regulated EZH2 expression and resulted in demethylation of CXXC4 and SFRP2 through the Wnt/β-catenin signaling pathway.

CONCLUSION

We concluded that LUCAT1 induces methylation of CXXC4 and SFRP2, thereby regulating Wnt/β-catenin signaling in GC.

Effects of miR-384 and miR-134-5p Acting on YY1 Signaling Transduction on Biological Function of Gastric Cancer Cells

Objective

To explore the related influencing mechanism of miR-384 and miR-134-5p acting on Yin Yang 1 (YY1) signaling transduction on the biological function of gastric cancer (GC) cells.

Methods

miR-384, miR-134-5p and YY1 levels in human GC cell lines KATO III, MKN-45, SNU-1 and normal gastric cell line GES-1 were measured by polymerase chain reaction (PCR). Dual luciferase reporter (DLR) gene assay and Western blot (WB) were employed for correlation analysis between miR-384, miR-134-5p and YY1. miR-384-inhibitor, miR-384-mimics, empty plasmid (miRNA-NC) and sh-YY1 were transfected into KATO III cells. Cell proliferation was determined by 3-(4,5-Dimethylthiazolyl-2)-2,5-Diphenyl Tetrazolium Bromide (MTT), cell invasion was measured by Transwell, and apoptosis was analyzed by flow cytometry (FC).

Results

In KATO III, MKN-45 and SNU-1 cell lines, YY1 was upregulated while miR-384 and miR-134-5p were downregulated (P<0.001). The expression of miR-134-5p in the miR-134-5p-inhibitor group was significantly lower (P<0.001), while that in the miR-134-5p-mimics group was significantly higher (P<0.001). The expression of miR-384 in the miR-384-inhibitor group was significantly lower (P<0.001), and that in the miR-384-mimics group was significantly higher as compared to the NC group (P<0.001). Both miR-384 and miR-134-5p overexpression could inhibit cell proliferation and invasion, and promote apoptosis. As detected by WB, overexpressed miR-384 and miR-134-5p inhibited the expression of EMT-related molecular markers. Compared with sh-YY1, the number of cells in S phase decreased, the pro-apoptotic proteins boosted statistically, and the anti-apoptotic proteins declined notably after transfecting miR-134-5p-mimics/sh-YY1 or miR-384-mimics/sh-YY1 (P<0.05). The tumor growth rate of nude mice in miR-134-5p/sh-YY1 and miR-384/sh-YY1 groups were significantly lower than those in sh-YY1 group (all P<0.001).

Conclusion

By targeting YY1 signaling transduction, miR-134-5p and miR-384 can alter the growth and apoptosis of GC cells, which are promising targets for new therapeutics of GC.

Long non-coding RNA LINC00858 aggravates the oncogenic phenotypes of ovarian cancer cells through miR-134-5p/RAD18 signaling

PURPOSE

Ovarian cancer is a common gynecological cancer. Herein, we focused on the function and probable mechanisms of LINC00858 in ovarian cancer.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) was employed for detecting the expression of LINC00858, miR-134-5p and RAD18 E3 ubiquitin protein ligase (RAD18). Cell proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) and apoptosis were detected by cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), transwell, terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) and western bolt experiments, as appropriate. Interplays between LINC00858, miR-134-5p and RAD18 were detected by RNA immunoprecipitation (RIP), RNA pull down and luciferase reporter assays.

RESULTS

LINC00858 were up-regulated in ovarian cancer tissues and cells, and its expression was elevated in advanced samples compared to early ones. Knocking down LINC00858 inhibited cell proliferation, motility and EMT, but accelerated cell apoptosis in ovarian cancer. Moreover, could be sponged by LINC00858 sponged miR-134-5p to enhance RAD18 expression in ovarian cancer. Also, silenced RAD18 could also restrain oncogenic behaviors of ovarian cancer cells. Rescue experiments showed that overexpressing RAD18 reversed the effects caused by knocking down LINC00858 on cellular processes.

CONCLUSION

LINC00858 sequestered miR-134-5p to elevate RAD18 expression, resulting in aggravated development of ovarian cancer. This might provide promising targets for treating patients with ovarian cancer.

Circular RNA circNHSL1 Contributes to Gastric Cancer Progression Through the miR-149-5p/YWHAZ Axis

Background

Gastric cancer (GC) is a considerable health burden around the world. Circular RNA Nance-Horan syndrome-like 1 (circNHSL1) is reported to be highly expressed in GC. Nevertheless, the function and molecule mechanism of circNHSL1 are still unclear.

Methods

The expression levels of circNHSL1, microRNA-149-5p (miR-149-5p) and YWHAZ were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The subcellular fractionation identified the remarkable cytoplasmic localization of circNHSL1. Cell migration and invasion were measured by transwell assays. The levels of glutamine, glutamate and α-ketoglutarate (α-KG) were assessed by the corresponding kit. The protein levels of CD63, CD9, CD81, alanine, serine, cysteine-preferring transporter 2 (ASCT2), glutaminase 1 (GLS1), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) were detected by Western blot assay. The binding relationship between miR-149-5p and circNHSL1 or YWHAZ was predicted by starBase 3.0 and then verified by RNA pull-down and dual-luciferase reporter assays. Xenograft tumor model examined the biological role of circNHSL1 in vivo. Exosomes were examined by a transmission electron microscope and nanoparticle tracking analysis (NTA).

Results

CircNHSL1 was highly expressed in GC cell-derived exosomes, GC tissues, and cells. Its knockdown impeded GC cell migration, invasion, and glutaminolysis. Mechanism analysis showed that circNHSL1 could affect YWHAZ expression by sponging miR-149-5p, thereby regulating GC progression. CircNHSL1 downregulation blocked GC tumor growth in vivo.

Conclusion

Our studies disclosed that circNHSL1 knockdown repressed migration, invasion, and glutaminolysis in vitro and inhibited tumor growth in vivo by miR-149-5p/YWHAZ axis in GC, implying an underlying circRNA-targeted therapy for GC treatment.

The Ubiquitin Gene Expression Pattern and Sensitivity to UBB and UBC Knockdown Differentiate Primary 23132/87 and Metastatic MKN45 Gastric Cancer Cells

Gastric cancer (GC) is one of the most common and lethal cancers. Alterations in the ubiquitin (Ub) system play key roles in the carcinogenetic process and in metastasis development. Overexpression of transcription factors YY1, HSF1 and SP1, known to regulate Ub gene expression, is a predictor of poor prognosis and shorter survival in several cancers. In this study, we compared a primary (23132/87) and a metastatic (MKN45) GC cell line. We found a statistically significant higher expression of three out of four Ub coding genes, UBC, UBB and RPS27A, in MKN45 compared to 23132/87. However, while the total Ub protein content and the distribution of Ub between the conjugated and free pools were similar in these two GC cell lines, the proteasome activity was higher in MKN45. Ub gene expression was not affected upon YY1, HSF1 or SP1 small interfering RNA (siRNA) transfection, in both 23132/87 and MKN45 cell lines. Interestingly, the simultaneous knockdown of UBB and UBC mRNAs reduced the Ub content in both cell lines, but was more critical in the primary GC cell line 23132/87, causing a reduction in cell viability due to apoptosis induction and a decrease in the oncoprotein and metastatization marker β-catenin levels. Our results identify UBB and UBC as pro-survival genes in primary gastric adenocarcinoma 23132/87 cells.

miR-134-5p inhibition reduces infarct-induced cardiomyocyte apoptosis via Creb1 upregulation

BACKGROUND

Following the recent discovery that microRNA-134-5p (miR-134-5p) is elevated in the early stages of acute myocardial infarction (AMI), we examined the specific role of miR-134-5p in cardiomyocytes during AMI.

METHODS

To study miR-134-5p's role in the context of AMI, we used a combination of in vitro experiments in H₂O₂-treated or hypoxic cardiomyocyte cell cultures as well as in vivo experiments in a murine model of AMI.

RESULTS

H₂O₂- and hypoxia-induced cardiomyocyte injury upregulated miR-134-5p expression. miR-134-5p overexpression increased cardiomyocyte apoptosis, whereas miR-134-5p inhibition reduced cardiomyocyte apoptosis. We discovered that the transcription factor cAMP-responsive element binding protein 1 (Creb1) is a functional target of miR-134-5p responsible for regulating cardiomyocyte apoptosis. In vivo AMI resulted in the upregulation and downregulation of miR-134-5p and Creb1 in the infarct area, respectively. Circulating miR-134-5p levels were also increased at days 1 and 2 post-AMI. Modulation of myocardial miR-124-5p expression by intramyocardial injection of antagomiR-134-5p or agomiR-134-5p significantly affected cardiomyocyte apoptosis, infarct size, and cardiac function in vivo.

CONCLUSIONS

miR-134-5p/Creb1 axis dysregulation plays a role in hypoxia- or oxidative stress-induced cardiomyocyte apoptosis as well as AMI. Circulating miR-134-5p may show promise as a biomarker for AMI or post-AMI cardiac dysfunction. Manipulating the miR-134-5p/Creb1 axis through either inhibition of miR-134-5p or overexpression of Creb1 may show promise as a novel therapeutic strategy to attenuate cardiac dysfunction following AMI.

The role of YWHAZ in cancer: A maze of opportunities and challenges

YWHAZ (also named 14-3-3ζ) is a central hub protein for many signal transduction pathways and plays a significant role in tumor progression. Accumulating evidences have demonstrated that YWHAZ is frequently up-regulated in multiple types of cancers and acts as an oncogene in a wide range of cell activities including cell growth, cell cycle, apoptosis, migration, and invasion. Moreover, YWHAZ was reported to be regulated by microRNAs (miRNAs) or long non-coding RNAs and exerted its malignant functions by targeting downstream molecules like protein kinase, apoptosis proteins, and metastasis-related molecules. Additionally, YWHAZ may be a potential biomarker of diagnosis, prognosis and chemoresistance in several cancers. Targeting YWHAZ by siRNA, shRNA or miRNA was reported to have great help in suppressing malignant properties of cancer cells. In this review, we perform literature and bioinformatics analysis to reveal the oncogenic role and molecular mechanism of YWHAZ in cancer, and discuss the potential clinical applications of YWHAZ concerning diagnosis, prognosis, and therapy in malignant tumors.

Global Analysis of miRNA Signature Differentially Expressed in Insulin-resistant Human Hepatocellular Carcinoma Cell Line

Chemoresistance mediated by insulin resistance (IR) in HCC has already been validated. However, the underlying mechanism, especially the involvement of microRNAs (miRNAs) was unelucidated. In this study, miRNA microarrays and bioinformatics methods were employed to determine the dysregulation of miRNA by IR in HCC cells, and quantitative RT-PCR (qRT-PCR) was applied to valid the miRNA array data. Of all the 2006 miRNAs screened, 32 miRNAs were found up or down regulated between the HepG2/IR cells and its parental cells. Further literature mining revealed that some of these miRNAs may function as oncogenes or tumor suppressors that contribute to tumor progression, recurrence, and metastasis which eventually lead to chemotherapeutic resistance. Interestingly, bioinformatics analysis by Gene Ontology (GO) enrichment pathway indicating that function of the predicted target genes of these dysregulated miRNAs were significantly enriched in the processes related with biosynthesis, catabolism, modification etc., and Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping showed that the biological regulatory mechanisms were integrated in cancer-related pathways. Moreover, we also constructed a network which connected the differentially expressed miRNAs to target genes, GO enrichments and KEGG pathways to reveal the hub miRNAs, genes and pathways. Collectively, our present study demonstrated the possible miRNAs and predicted target genes involving in the pathophysiology of insulin resistant HCC, providing novel insights into the molecular mechanisms of multidrug resistance in the insulin resistant HepG2 cells.