Antisense lncRNA LDLRAD4-AS1 promotes metastasis by decreasing the expression of LDLRAD4 and predicts a poor prognosis in colorectal cancer

Long noncoding RNA LINC01550 inhibits colorectal cancer malignancy by suppressing the Wnt/β-catenin signaling pathway

Colorectal cancer (CRC) is a common gastrointestinal malignancy. Long noncoding RNAs (lncRNAs) are associated with the progression of various cancers, including CRC. Herein, we explored the function of lncRNA LINC01550 in CRC. LINC01550 expression in CRC was analyzed using The Cancer Genome Atlas (TCGA). The diagnostic value of LINC01550 was evaluated using ROC curves. The relationship between clinicopathological variables and LINC01550 expression was explored, and its prognostic value was assessed using Kaplan-Meier and Cox regression analyses. The relationship between LINC01550 expression and immune cell infiltration was analyzed using CIBERSORT. Tumor-associated mutations and drug sensitivity were compared between high and low LINC01550 expression groups. The effects of LINC01550 overexpression on CRC cells were investigated using CCK-8, flow cytometry, wound healing, Transwell, qRT-PCR, and western blot assays. LINC01550 was downregulated in CRC tissues, and the low expression of LINC01550 was correlated with advanced stage and metastasis. CRC patients with low LINC01550 expression had poorer overall survival. LINC01550 expression was an independent risk factor for CRC prognosis. APC and TP53 mutations were more frequent in the low LINC01550 expression group, while the high LINC01550 expression group was significantly more sensitive to 5-fluorouracil, irinotecan, trametinib, gemcitabine, rapamycin, and XAV939. LINC01550 overexpression suppressed the proliferation, migration, invasion, and epithelial-mesenchymal transition of HCT-116 and HT-29 cells and promoted apoptosis. LINC01550 exerted these effects by inhibiting Wnt/β-catenin signaling. Our results suggest LINC01550 as a diagnostic and prognostic predictor in CRC that acts as a tumor suppressor and a potential therapeutic target.

Identification of ASMTL-AS1 and LINC02604 lncRNAs as novel biomarkers for diagnosis of colorectal cancer

PURPOSE

Colorectal cancer is one of the major leading causes of death worldwide, and available treatments for advanced colorectal cancer are not successful. Therefore, early detection of colorectal cancer is essential to improve patient survival, and biomarkers are potential tools to achieve this goal. Considering the key role of lncRNAs in cancers, the aim of this study is to identify lncRNAs involved in colorectal cancer as new potential prognosis biomarkers for CRC.

METHODS

In this observational study, gene expression data obtained from the TCGA database were analyzed, Identification of differentially expressed mRNAs, miRNAs, and lncRNAs was performed, and ceRNA network was drawn. Also, survival analysis of patients was performed in order to identify potential biomarkers related to the diagnosis and prognosis of colon cancer. After confirming the results using the GSE39582 dataset, the expression of target lncRNAs in colorectal tumor tissues was also investigated to confirm the bioinformatic data.

RESULTS

Analysis of the TCGA data showed that the expression of three lncRNAs-SNHG7, ASMTL-AS1, and LINC02604-that had the highest interaction with other miRNAs and mRNAs identified based on the ceRNA network was increased in colorectal cancer. Also, based on the ceRNA network, three microRNAs, hsa-let-7d-5p, hsa-mir-92a-3p, and hsa-mir-423-5p, and eight mRNAs, including CPA4, MSI2, RRM2, IGF2BP1, ONECUT2, HMGA1, SOX4, and SRM, were associated with all three mentioned lncRNAs, the expression of microRNAs was decreased and the expression of mRNAs was increased. By enrichment analysis, it was found that the target lncRNAs are involved in the processes of cell proliferation, apoptosis, and metastasis, indicating their importance in the development and malignancy of colorectal cancer. Furthermore, Kaplan-Meier analysis showed a significant increase in mortality in patients with higher expression levels of these lncRNAs. Analysis of the GSE39582 dataset, and real-time RT-PCR analysis, confirmed our bioinformatic results. Also, ROC analysis showed that SNHG7 was a relatively good promising biomarker (AUC = 0.73, p value = 0.02), while ASMTL-AS1 (AUC = 0.92, p value < 0.0001) and LINC02604 (AUC = 1.00, p value < 0.0001) emerged as excellent diagnostic biomarkers in colorectal cancer.

CONCLUSION

It seems that increased expression of lncRNAs ASMTL-AS1 and LINC02604 can serve as molecular biomarkers for CRC, possibly through the sponge hsa-let-7d-5p, hsa-mir-92a-3p, and hsa-mir-423 5p, which increases target mRNAs, which are effective in the carcinogenesis process.

Exosomal lncRNA USP30-AS1 activates the Wnt/β-catenin signaling pathway to promote cervical cancer progression via stabilization of β-catenin by USP30

Cervical cancer (CC) remains a major cause of cancer-related mortality among women globally. Long noncoding RNAs (lncRNAs) play crucial regulatory roles in various cancers, including CC. This study investigates the function of a novel lncRNA, USP30 antisense RNA 1 (USP30-AS1), in CC tumorigenesis. We analyzed USP30-AS1 expression using RT-qPCR and conducted in vitro loss-of-function assays, as well as in vivo assays, to evaluate the effects of USP30-AS1 silencing on CC cell growth and migration. Additional mechanistic experiments, including RNA pull-down, RNA immunoprecipitation (RIP), and co-immunoprecipitation (Co-IP) assays, were performed to elucidate the regulatory mechanisms influenced by USP30-AS1. We discovered that USP30-AS1 is overexpressed in CC tissues and cells. Silencing USP30-AS1 significantly reduced cell proliferation, migration, invasion, and tumor growth. Moreover, USP30-AS1 was found to modulate the expression of ubiquitin-specific peptidase 30 (USP30) by sponging microRNA-2467-3p (miR-2467-3p) and recruiting the FUS RNA binding protein (FUS), thereby stabilizing β-catenin and activating the Wnt/β-catenin signaling pathway. These findings suggest that USP30-AS1 enhances CC cell growth and migration through the miR-2467-3p/FUS/USP30 axis, highlighting its potential as a biomarker for CC.

Downregulated antisense lncRNA ENTPD3-AS1 contributes to the development of lung adenocarcinoma

The poor outcome of patients with lung adenocarcinoma (LUAD) highlights the importance to identify novel effective prognostic markers and therapeutic targets. Long noncoding RNAs (lncRNAs) have generally been considered to serve important roles in tumorigenesis and the development of various types of cancer, including LUAD. Here, we aimed to investigate the role of ENTPD3-AS1 (ENTPD3 Antisense RNA 1) in LUAD and to explore its potential mechanisms by performing comprehensive bioinformatic analyses. The regulatory effect of ENTPD3-AS1 on the expression of NR3C1 was validated by siRNA-based silencing. The effect of miR-421 on the modulation of NR3C1 was determined by miRNA mimics and inhibitors transfection. ENTPD3-AS1 was expressed at lower levels in tumor parts and negatively correlated with unfavorable prognosis in LUAD patients. It exerted functions as a tumor suppressor gene by competitively binding to oncomir, miR-421, thereby attenuating NR3C1 expression. Transfection of lung cancer A549 cells with miR-421 mimics decreased the expression of NR3C1. Transfection of lung cancer A549 cells with miR-421 inhibitors increased the expression of NR3C1 with lower cellular functions as proliferation and migration via epithelial-mesenchymal transition. In addition, inhibition of ENTPD3-AS1 by siRNA transfection decreased the levels of NR3C1, supporting the ENTPD3-AS1/miR-421/NR3C1 cascade. Moreover, the bioinformatic analysis also showed that ENTPD3-AS1 could interact with the RNA-binding proteins (RBPs), CELF2 and QKI, consequently regulating RNA expression and processing. Taken together, we identified that ENTPD3-AS1 and its indirect target NR3C1 can act as novel biomarkers for determining the prognosis of patients with LUAD, and further study is required.

Identification of Long Non-Coding RNA Profiles and Potential Therapeutic Agents for Fibrolamellar Carcinoma Based on RNA-Sequencing Data

BACKGROUND

Fibrolamellar carcinoma (FLC) is a rare type of liver cancer that primarily affects adolescents and young adults without prior liver disease or viral infections. Patients with FLC generally have non-specific symptoms, are often diagnosed at a later stage, and experience a higher frequency of metastases compared to patients with other liver cancers. A fusion transcript of DNAJB1 and PRKACA, which can lead to increased activity of PKA and cellular proliferation, has been identified in all FLC patients, but the exact mechanism through which FLC develops remains unclear. In this study, we investigated common lncRNA profiles in various FLC samples using bioinformatics analyses.

METHODS

We analyzed differentially expressed (DE) lncRNAs from three RNA sequencing datasets. Using lncRNAs and DE mRNAs, we predicted potential lncRNA target genes and performed Gene Ontology (GO) and KEGG analyses with the DE lncRNA target genes. Moreover, we screened for small-molecule compounds that could act as therapeutic targets for FLC.

RESULTS

We identified 308 DE lncRNAs from the RNA sequencing datasets. In addition, we performed a trans-target prediction analysis and identified 454 co-expressed pairs in FLC. The GO analysis showed that the lncRNA-related up-regulated mRNAs were enriched in the regulation of protein kinase C signaling and cAMP catabolic processes, while lncRNA-related down-regulated mRNAs were enriched in steroid, retinol, cholesterol, and xenobiotic metabolic processes. The analysis of small-molecule compounds for FLC treatment identified vitexin, chlorthalidone, triamterene, and amiloride, among other compounds.

CONCLUSIONS

We identified potential therapeutic targets for FLC, including lncRNA target genes as well as small-molecule compounds that could potentially be used as treatments. Our findings could contribute to furthering our understanding of FLC and providing potential avenues for diagnosis and treatment.

Integrated analysis of the lncRNA-associated ceRNA network in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that worsens with age. Long non-coding RNAs (lncRNAs) dysregulation and its associated competing endogenous RNA (ceRNA) network have a potential connection with the occurrence and development of AD. A total of 358 differentially expressed genes (DEGs) were screened via RNA sequencing, including 302 differentially expressed mRNAs (DEmRNAs) and 56 differential expressed lncRNAs (DElncRNAs). Anti-sense lncRNA is the main type of DElncRNA, which plays a major role in the cis and trans regulation. The constructed ceRNA network consisted of 4 lncRNAs (NEAT1, LINC00365, FBXL19-AS1, RAI1-AS1719) and 4 microRNAs (miRNAs) (HSA-Mir-27a-3p, HSA-Mir-20b-5p, HSA-Mir-17-5p, HSA-Mir-125b-5p), and 2 mRNAs (MKNK2, F3). Functional enrichment analysis revealed that DEmRNAs are involved in related biological functions of AD. The co-expressed DEmRNAs (DNAH11, HGFAC, TJP3, TAC1, SPTSSB, SOWAHB, RGS4, ADCYAP1) of humans and mice were screened and verified by real-time quantitative polymerase chain reaction (qRT-PCR). In this study, we analyzed the expression profile of human AD-related lncRNA genes, constructed a ceRNA network, and performed functional enrichment analysis of DEmRNAs between human and mice. The obtained gene regulatory networks and target genes can be used to further analyze AD-related pathological mechanisms to optimize AD diagnosis and treatment.

The Roles of Antisense Long Noncoding RNAs in Tumorigenesis and Development through Cis-Regulation of Neighbouring Genes

Antisense long noncoding RNA (as-lncRNA) is a lncRNA transcribed in reverse orientation that is partially or completely complementary to the corresponding sense protein-coding or noncoding genes. As-lncRNAs, one of the natural antisense transcripts (NATs), can regulate the expression of their adjacent sense genes through a variety of mechanisms, affect the biological activities of cells, and further participate in the occurrence and development of a variety of tumours. This study explores the functional roles of as-lncRNAs, which can cis-regulate protein-coding sense genes, in tumour aetiology to understand the occurrence and development of malignant tumours in depth and provide a better theoretical basis for tumour therapy targeting lncRNAs.

Unraveling the function of epithelial-mesenchymal transition (EMT) in colorectal cancer: Metastasis, therapy response, and revisiting molecular pathways

Colorectal cancer (CRC) is a dangerous form of cancer that affects the gastrointestinal tract. It is a major global health concern, and the aggressive behavior of tumor cells makes it difficult to treat, leading to poor survival rates for patients. One major challenge in treating CRC is the metastasis, or spread, of the cancer, which is a major cause of death. In order to improve the prognosis for patients with CRC, it is necessary to focus on ways to inhibit the cancer's ability to invade and spread. Epithelial-mesenchymal transition (EMT) is a process that is linked to the spread of cancer cells, also known as metastasis. The process transforms epithelial cells into mesenchymal ones, increasing their mobility and ability to invade other tissues. This has been shown to be a key mechanism in the progression of colorectal cancer (CRC), a particularly aggressive form of gastrointestinal cancer. The activation of EMT leads to increases in the spread of CRC cells, and during this process, levels of the protein E-cadherin decrease while levels of N-cadherin and vimentin increase. EMT also contributes to the development of resistance to chemotherapy and radiation therapy in CRC. Non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a role in regulating EMT in CRC, often through their ability to "sponge" microRNAs. Anti-cancer agents have been shown to suppress EMT and reduce the progression and spread of CRC cells. These findings suggest that targeting EMT or related mechanisms may be a promising approach for treating CRC patients in the clinic.

LARRPM restricts lung adenocarcinoma progression and M2 macrophage polarization through epigenetically regulating LINC00240 and CSF1

BACKGROUND

Long non-coding RNAs (lncRNAs) are critical regulators in lung adenocarcinoma (LUAD). M2-type tumor-associated macrophages (TAMs) also play oncogenic roles in LUAD. However, the involvement of lncRNAs in TAM activation is still largely unknown.

METHODS

The expressions of LARRPM, LINC00240 and CSF1 were determined by RT-qPCR. The regulation of LINC00240 and CSF1 by LARRPM was investigated by RNA-protein pull-down, RNA immunoprecipitation, chromatin immunoprecipitation and bisulfite DNA sequencing. In vitro and in vivo gain- and loss-of-function assays were performed to investigate the roles of LARRPM.

RESULTS

The lncRNA LARRPM was expressed at low levels in LUAD tissues and cells. The low expression of LARRPM was correlated with advanced stage and poor survival of patients with LUAD. Functional experiments revealed that LARRPM suppressed LUAD cell proliferation, migration and invasion, and promoted apoptosis. LARRPM also repressed macrophage M2 polarization and infiltration. Taken together, LARRPM significantly restricted LUAD progression in vivo. Mechanistically, LARRPM bound and recruited DNA demethylase TET1 to the promoter of its anti-sense strand gene LINC00240, leading to a decrease in DNA methylation level of the LINC00240 promoter and transcriptional activation of LINC00240. Functional rescue assays suggested that the lncRNA LINC00240 was responsible for the roles of LARRPM in the malignant behavior of LUAD cells. LARRPM decreased the binding of TET1 to the CSF1 promoter, resulting in increased DNA methylation of the CSF1 promoter and transcriptional repression of CSF1, which is responsible for the roles of LARRPM in macrophage M2 polarization and infiltration. The TAMs educated by LUAD cells exerted oncogenic roles, which was negatively regulated by LARRPM expressed in LUAD cells.

CONCLUSIONS

LARRPM restricts LUAD progression through repressing both LUAD cell and macrophages. These data shed new insights into the regulation of LUAD progression by lncRNAs and provide data on the potential utility of LARRPM as a target for LUAD treatment.

Development of a novel hypoxia-immune–related LncRNA risk signature for predicting the prognosis and immunotherapy response of colorectal cancer

Background

Colorectal cancer (CRC) is one of the most common digestive system tumors worldwide. Hypoxia and immunity are closely related in CRC; however, the role of hypoxia-immune–related lncRNAs in CRC prognosis is unknown.

Methods

Data used in the current study were sourced from the Gene Expression Omnibus and The Cancer Genome Atlas (TCGA) databases. CRC patients were divided into low- and high-hypoxia groups using the single-sample gene set enrichment analysis (ssGSEA) algorithm and into low- and high-immune groups using the Estimation of STromal and Immune cells in MAlignant Tumours using Expression data (ESTIMATE) algorithm. Differentially expressed lncRNAs (DElncRNAs) between low- and high-hypoxia groups, low- and high-immune groups, and tumor and control samples were identified using the limma package. Hypoxia-immune–related lncRNAs were obtained by intersecting these DElncRNAs. A hypoxia-immune–related lncRNA risk signature was developed using univariate Cox regression and least absolute shrinkage and selection operator (LASSO) analyses. The tumor microenvironments in the low- and high-risk groups were evaluated using ssGSEA, ESTIMATE, and the expression of immune checkpoints. The therapeutic response in the two groups was assessed using TIDE, IPS, and IC50. A ceRNA network based on signature lncRNAs was constructed. Finally, we used RT-qPCR to verify the expression of hypoxia-immune–related lncRNA signatures in normal and cancer tissues.

Results

Using differential expression analysis, and univariate Cox and LASSO regression analyses, ZNF667-AS1, LINC01354, LINC00996, DANCR, CECR7, and LINC01116 were selected to construct a hypoxia-immune–related lncRNA signature. The performance of the risk signature in predicting CRC prognosis was validated in internal and external datasets, as evidenced by receiver operating characteristic curves. In addition, we observed significant differences in the tumor microenvironment and immunotherapy response between low- and high-risk groups and constructed a CECR7–miRNA–mRNA regulatory network in CRC. Furthermore, RT-qPCR results confirmed that the expression patterns of the six lncRNA signatures were consistent with those in TCGA-CRC cohort.

Conclusion

Our study identified six hypoxia-immune–related lncRNAs for predicting CRC survival and sensitivity to immunotherapy. These findings may enrich our understanding of CRC and help improve CRC treatment. However, large-scale long-term follow-up studies are required for verification.

Whole transcriptome and proteome analyses identify potential targets and mechanisms underlying tumor treating fields against glioblastoma

Glioblastoma (GBM) is one of the most malignant types of brain cancer. Tumor treating fields (TTFields) is the up-to-date treatment for GBM. However, its molecular mechanism requires additional investigation. Herein, a novel TTFields system was developed (CL-301A) and its efficiency in suppressing GBM cell proliferation and inducing cell apoptosis was demonstrated. Through the whole proteomic and transcriptomic analyses, a multitude of differentially expressed proteins (1243), mRNAs (4191), miRtNAs (47), lncRNAs (4286), and circRNAs (13,903) were identified. Bioinformatic analysis indicated that TTFields mainly affected nuclear proteins and interrupt cell mitosis-related events. Moreover, the inhibition of autophagy could significantly enhance the anti-GBM activity of TTFields. And CDK2-AS1 might be a target of TTFields to mediate cell cycle arrest via regulating CDK2 mRNA stability. This study provided valuable resources for understanding the mechanism of TTFields, which might further assist the investigation of TTFields in GBM treatment.

LncRNAs as epigenetic regulators of epithelial to mesenchymal transition in pancreatic cancer

Pancreatic cancer is the leading cause of cancer-related mortality because of tumor metastasis. Activation of the epithelial-to-mesenchymal transition (EMT) pathway has been confirmed to be an important driver of pancreatic cancer progression from initiation to metastasis. Long noncoding RNAs (lncRNAs) have been reported to exert essential physiological functions in pancreatic cancer progression by regulating the EMT program. In this review, we have summarized the role of EMT-related lncRNAs in human pancreatic cancer and the potential molecular mechanisms by which lncRNAs can be vital epigenetic regulators of epithelial to mesenchymal transition. Specifically, EMT-activating transcription factors (EMT-TFs) regulate EMT via TGF-β/Smad, Wnt/β-catenin, and JAK/STAT pathways. In addition, the interaction between lncRNAs and HIF-1α and m6A RNA methylation also have an impact on tumor metastasis and EMT in pancreatic cancer. This review will provide insights into lncRNAs as promising biomarkers for tumor metastasis and potential therapeutic strategies for pancreatic cancer.

Asperuloside inhibited epithelial-mesenchymal transition in colitis associated cancer via activation of vitamin D receptor

BACKGROUND

Asperuloside is a natural compound extracted from various herbs with several bioactivities. Its effects on anti-inflammation and anti-tumor indicated that asperuloside might prevent colorectal cancer developing from inflammatory bowel diseases (IBD). But there were few reports about the efficacy and mechanism of asperuloside on improving colorectal cancer. It has been reported that vitamin D receptor (VDR) could regulate the expression of SMAD3. In previous study, asperuloside could significantly improve the expression of VDR and reduced Smad3 mRNA in IEC-6 cell.

PURPOSE

The present study was aimed to investigate the potential mechanism of asperuloside on inhibiting epithelial-mesenchymal transition (EMT) in colitis associated cancer.

STUDY DESIGN

First, in LPS-injured IEC-6 cell, asperuloside inhibited phosphorylated p65 (p-p65) level, improved VDR expression and reduced Smad3 mRNA. Second, we wonder the relationship between VDR signaling and nucleus factor-kappaB (NF-κB) signaling during asperuloside on reducing Smad3 mRNA. And then, the effect of asperuloside on inhibiting EMT development through VDR/Smad3 was investigated. Finally, we testified the effect of asperuloside on protecting against colitis associated cancer (CAC) by inhibiting EMT development through VDR/Smad3.

METHODS

Pyrrolidinedithiocarbamate ammonium (PDTC) was used for established NF-κB-inhibited IEC-6 cell. This cell was applied for investigating the relationship between NF-κB and VDR of asperuloside on inhibiting Smad3. VDR-inhibited cell was established by small interfering RNA (siRNA) of VDR and was employed to investigate the role of VDR for asperuloside on decreasing Smad3. Transforming growth factor β1 (TGFβ1) was used for inducing EMT/fibrosis in IEC-6 cell. TGFβ1-stimulated cell was used for testifying the effect of asperuloside on inhibiting EMT development. AOM/DSS-induced CAC was established to investigate the effect of asperuloside on suppressing cancer development.

RESULTS

Asperuloside inhibited the level of p-p65 which was up-regulated by LPS. Asperuloside could up-regulate VDR signaling and reduce Smad3 mRNA in NF-κB-knockdown IEC-6 cells. Asperuloside failed to reduce Smad3 mRNA due to VDR knockdown, which implied that asperuloside might down-regulate Smad3 mRNA dependently on activation of VDR signaling and independently on inhibiting NF-κB signaling. Asperuloside exhibited significant prevention of EMT development in TGFβ1-induced IEC-6 cell (EMT cell) and mice CAC. Asperuloside reduced the transform of epithelial phenotype into motile mesenchymal phenotype in EMT cell along with decreasing levels of EMT markers by inhibiting Smad3 mRNA via activation of VDR. In mice with CAC, expression of VDR in colon was improved by asperuloside. Symptoms of colitis, tumor number and tumor size were significantly inhibited by asperuloside. Suppressed EMT development was determined by reduced α-SMA expression and decreased mRNAs of several EMT markers.

CONCLUSION

Asperuloside might prevent CAC through inhibiting EMT development via regulation of VDR/Smad3 pathway.

RASSF8-AS1 displays low expression in colorectal cancer and up-regulates RASSF8 to suppress cell invasion and migration

BACKGROUND

Colorectal cancer (CRC) is among the most prevalent cancers. Long non-coding RNAs (lncRNAs) are important participant in various cancers. Based on the literature, lncRNA RASSF8-AS1 inhibits laryngeal squamous cell carcinoma (LSCC) malignant progression. However, the role of RASSF8-AS1 in CRC remains unclear.

PURPOSE

This study centered on uncovering the role of RASSF8-AS1 and its related regulatory mechanisms in CRC cells.

METHODS

RT-qPCR and western blot were performed to examine the expression of target genes. Functional assays were conducted to determine the effect of target genes on the migration and invasion of CRC cells. Mechanism assays were also carried out to figure out the specific downstream mechanisms of RASSF8-AS1. In vivo assays were also involved.

RESULTS

The expression of RASSF8-AS1 and RASSF8 was positively correlated in CRC, and the two genes were down-regulated in CRC cells and tissues. Moreover, CRC cell invasion and migration as well as xenograft CRC tumor growth suppressed by RASSF8-AS1 overexpression were entirely recovered by RASSF8 knockdown or partially rescued by miR-33a-5p augment. As for the downstream mechanism, RASSF8-AS1 sponged miR-33a-5p to up-regulate RASSF8, or recruited HNRNPC to stabilize RASSF8 mRNA.

CONCLUSION

RASSF8-AS1 modulates miR-33a-5p/HNRNPC/RASSF8 axis to further impede CRC cell invasion and migration.

AVAILABILITY OF DATA

The research data is confidential.

The lncARSR/PTEN/Akt/nuclear factor-kappa B feedback regulatory loop contributes to doxorubicin resistance in hepatocellular carcinoma

Chemoresistance is a major obstacle to hepatocellular carcinoma (HCC) chemotherapy. Our previous study found that long noncoding RNA lncARSR (lncRNA Activated in RCC with Sunitinib Resistance) activated Akt signaling via repressing phosphatase and tensin homolog (PTEN) during doxorubicin resistance in HCC. The purpose of this study is to further explore lncARSR-mediated mechanisms and roles during doxorubicin resistance in HCC. The expression of lncARSR was detected by real-time quantitative polymerase chain reaction (qPCR). Nuclear factor-kappa B (NF-κB) activity was detected by NF-κB luciferase reporter assays, western blot, and NF-κB transcription factor assays. The effects of NF-κB on lncARSR were detected by chromatin immunoprecipitation assay, promoter luciferase reporter assay, and real-time qPCR. The effects of lncARSR/Akt/NF-κB on doxorubicin resistance were detected by Cell Counting Kit-8 assay, capsase-3 activity assay, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. lncARSR activated NF-κB signaling through activation of Akt. NF-κB transactivated lncARSR through directly binding lncARSR promoter and increasing lncARSR promoter activity. Akt transactivated lncARSR via activating NF-κB signaling. Thus, lncARSR, Akt, and NF-κB formed a positive feedback regulatory loop in HCC. Through this feedback loop, lncARSR auto-regulated its transcription. Drug sensitivity assays showed that the lncARSR/Akt/NF-κB feedback regulatory loop promoted doxorubicin resistance in HCC. These findings identified the lncARSR/Akt/NF-κB feedback regulatory loop in HCC, which represent potential therapeutic targets for improving doxorubicin sensitivity in HCC.

CTB-193M12.5 Promotes Hepatocellular Carcinoma Progression via Enhancing NSD1-Mediated WNT10B/Wnt/β-Catenin Signaling Activation

Background

Methods

Results

Conclusion

METTL16 promotes hepatocellular carcinoma progression through downregulating RAB11B-AS1 in an m6A-dependent manner

BACKGROUND

The molecular mechanisms driving hepatocellular carcinoma (HCC) remain largely unclear. As one of the major epitranscriptomic modifications, N6-methyladenosine (m6A) plays key roles in HCC. The aim of this study was to investigate the expression, roles, and mechanisms of action of the RNA methyltransferase methyltransferase-like protein 16 (METTL16) in HCC.

METHODS

The expression of METTL16 and RAB11B-AS1 was determined by RT-qPCR. The regulation of RAB11B-AS1 by METTL16 was investigated by RNA immunoprecipitation (RIP), methylated RIP (MeRIP), and RNA stability assays. In vitro and in vivo gain- and loss-of-function assays were performed to investigate the roles of METTL16 and RAB11B-AS1.

RESULTS

METTL16 was upregulated in HCC, and its increased expression was correlated with poor prognosis of HCC patients. METTL16 promoted HCC cellular proliferation, migration, and invasion, repressed HCC cellular apoptosis, and promoted HCC tumoral growth in vivo. METTL16 directly bound long noncoding RNA (lncRNA) RAB11B-AS1, induced m6A modification of RAB11B-AS1, and decreased the stability of RAB11B-AS1 transcript, leading to the downregulation of RAB11B-AS1. Conversely to METTL16, RAB11B-AS1 is downregulated in HCC, and its decreased expression was correlated with poor prognosis of patients with HCC. Furthermore, the expression of RAB11B-AS1 was negatively correlated with METTL16 in HCC tissues. RAB11B-AS1 repressed HCC cellular proliferation, migration, and invasion, promoted HCC cellular apoptosis, and inhibited HCC tumoral growth in vivo. Functional rescue assays revealed that overexpression of RAB11B-AS1 reversed the oncogenic roles of METTL16 in HCC.

CONCLUSIONS

This study identified the METTL16/RAB11B-AS1 regulatory axis in HCC, which represented novel targets for HCC prognosis and treatment.

Long Non-Coding RNAs as Potential Regulators of EMT-Related Transcription Factors in Colorectal Cancer—A Systematic Review and Bioinformatics Analysis

Simple Summary

Emerging evidence highlights long non-coding RNAs as important regulators of epithelial–mesenchymal transition. Numerous studies have attempted to define their possible diagnostic, prognostic and therapeutic values in various human cancers. The aim of this review is to summarize long non-coding RNAs involved in the regulation of epithelial–mesenchymal transition in colorectal carcinoma. Additional candidate long non-coding RNAs are identified through a bioinformatics analysis.

Abstract

Epithelial–mesenchymal transition (EMT) plays a pivotal role in carcinogenesis, influencing cancer progression, metastases, stemness, immune evasion, metabolic reprogramming and therapeutic resistance. EMT in most carcinomas, including colorectal carcinoma (CRC), is only partial, and can be evidenced by identification of the underlying molecular drivers and their regulatory molecules. During EMT, cellular reprogramming is orchestrated by core EMT transcription factors (EMT-TFs), namely ZEB1/2, TWIST1/2, SNAI1 (SNAIL) and SNAI2 (SLUG). While microRNAs have been clearly defined as regulators of EMT, the role of long non-coding RNAs (lncRNAs) in EMT is poorly defined and controversial. Determining the role of lncRNAs in EMT remains a challenge, because they are involved in a number of cellular pathways and are operating through various mechanisms. Adding to the complexity, some lncRNAs have controversial functions across different tumor types, acting as EMT promotors in some tumors and as EMT suppressors in others. The aim of this review is to summarize the role of lncRNAs involved in the regulation of EMT-TFs in human CRC. Additional candidate lncRNAs were identified through a bioinformatics analysis.

Long non-coding RNA AC087388.1 as a novel biomarker in colorectal cancer

Background

Several investigations have reported diverse roles of long non-coding RNA (lncRNA) in biological processes, tumor development, and progression of colorectal cancer (CRC). In this study, we investigated the lncRNA AC087388.1 tumorigenic role in CRC cells.

Methods

The CRC tissues were collected at the Reza Radiotherapy and Oncology Center, Mashhad, Iran. The human SW-48 and HT-29 CRC cell lines were obtained from the national cell bank of Iran. The cells were cultured according to ATCC (the American Type Culture Collection) recommendations. Quantitative real-time PCR was applied to assess the RNA expression. ShRNA transfection was done to downregulate the target gene. MTT and apoptosis assays were conducted to evaluate cell proliferation and viability, respectively. Colony formation assay, wound healing assay, and invasion assay were applied to determine growth, motility, and invasion of the cells, respectively. ENCORI online tool was used as downstream enrichment analysis.

Results

Forty CRC patients were encompassed in this study. The results demonstrated that the lncRNA SLC16A1-AS1, AC087388.1, and ELFN1-AS1 were significantly overexpressed in the CRC tissues in comparison to their normal counterpart margins. All the lncRNAs have shown significant Area Under Curve (AUC) values in the patients. Downregulation of lncRNA AC087388.1 remarkably decreased the cell proliferation and viability of the CRC cells. In addition, the data demonstrated that the downregulation of lncRNA AC087388.1 significantly suppressed cell growth and colony formation capability in the cells. Also, downregulation of lncRNA AC087388.1 attenuated motility and invasion of CRC cells, and significantly decreased the expression of invasion genes. In-silico functional enrichment analysis indicated that the lncRNA AC087388.1 has contributed to crucial signaling pathways in tumorigenesis such as the p53 and Wnt signaling pathways, apoptosis, and cell cycle.

Conclusions

Altogether, we showed that lncRNA AC087388.1 has an oncogenic role in tumorigenesis of CRC, and it can be considered as a novel diagnostic and prognostic biomarker in CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09282-0.

Long non-coding RNAs as the critical regulators of epithelial mesenchymal transition in colorectal tumor cells: an overview

Colorectal cancer (CRC) is the second most common cause of cancer mortality and a major health challenge worldwide. Despite advances in therapeutic and diagnostic methods, there is still a poor prognosis in CRC patients. Tumor recurrence and metastasis are the main causes of high mortality rate in these patients, which are due to late diagnosis in advanced tumor stages. Epithelial-mesenchymal transition (EMT) is known to be the most important cause of CRC metastasis, during which tumor cells obtain metastasis ability by losing epithelial features and gaining mesenchymal features. Long non-coding RNAs (lncRNAs) are pivotal regulators of EMT process. Regarding the higher stability of lncRNAs compared with coding RNAs in body fluids, they can be used as non-invasive diagnostic markers for EMT process. In the present review, we summarized all of the lncRNAs involved in regulation of EMT process during CRC progression and metastasis. It was observed that lncRNAs mainly induced the EMT process in CRC cells by regulation of EMT-related transcription factors, Poly comb repressive complex (PRC), and also signaling pathways such as WNT, NOTCH, MAPK, and Hippo.

Long non-coding RNA PAARH promotes hepatocellular carcinoma progression and angiogenesis via upregulating HOTTIP and activating HIF-1α/VEGF signaling

Hepatocellular carcinoma (HCC) is one of the leading lethal malignancies and a hypervascular tumor. Although some long non-coding RNAs (lncRNAs) have been revealed to be involved in HCC. The contributions of lncRNAs to HCC progression and angiogenesis are still largely unknown. In this study, we identified a HCC-related lncRNA, CMB9-22P13.1, which was highly expressed and correlated with advanced stage, vascular invasion, and poor survival in HCC. We named this lncRNA Progression and Angiogenesis Associated RNA in HCC (PAARH). Gain- and loss-of function assays revealed that PAARH facilitated HCC cellular growth, migration, and invasion, repressed HCC cellular apoptosis, and promoted HCC tumor growth and angiogenesis in vivo. PAARH functioned as a competing endogenous RNA to upregulate HOTTIP via sponging miR-6760-5p, miR-6512-3p, miR-1298-5p, miR-6720-5p, miR-4516, and miR-6782-5p. The expression of PAARH was significantly positively associated with HOTTIP in HCC tissues. Functional rescue assays verified that HOTTIP was a critical mediator of the roles of PAARH in modulating HCC cellular growth, apoptosis, migration, and invasion. Furthermore, PAARH was found to physically bind hypoxia inducible factor-1 subunit alpha (HIF-1α), facilitate the recruitment of HIF-1α to VEGF promoter, and activate VEGF expression under hypoxia, which was responsible for the roles of PAARH in promoting angiogenesis. The expression of PAARH was positively associated with VEGF expression and microvessel density in HCC tissues. In conclusion, these findings demonstrated that PAARH promoted HCC progression and angiogenesis via upregulating HOTTIP and activating HIF-1α/VEGF signaling. PAARH represents a potential prognostic biomarker and therapeutic target for HCC.

LncRNA EIF1AX-AS1 promotes endometrial cancer cell apoptosis by affecting EIF1AX mRNA stabilization

Long non-coding RNAs (lncRNAs) have been found to play an important role in the occurrence and development of endometrial carcinoma (EC). Here, using RNA sequencing analysis, we systemically screened and identified the lncRNA EIF1AX-AS1, which is aberrantly down-regulated in clinical EC tissues and closely correlated with tumor type. EIF1AX-AS1 markedly inhibited EC cell proliferation and promoted apoptosis in vitro and in vivo. Mechanistically, EIF1AX-AS1 interacts with EIF1AX mRNA and poly C binding protein 1 (PCBP1), which promote eukaryotic translation initiation factor 1A, X-linked (EIF1AX) mRNA degradation. Intriguingly, interaction with IRES-related proteins Y-box binding protein 1 (YBX-1), EIF1AX promotes c-Myc translation through the internal ribosome enter site pathway. c-Myc promotes EIF1AX transcription and thus forms a feed-forward loop to regulate EC cell proliferation. Taken together, these data reveal new insights into the biology driving EC proliferation and highlights the potential of lncRNAs as biomarkers for prognosis and future therapeutic targets for cancer.

KB-68A7.1 Inhibits Hepatocellular Carcinoma Development Through Binding to NSD1 and Suppressing Wnt/β-Catenin Signalling

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies with extremely poor prognosis. Therefore, revealing the critical molecules involved in HCC progression and prognosis is urgently needed. In this study, through combining public dataset and our cohort, we found a novel prognosis-related long non-coding RNA KB-68A7.1 in HCC. KB-68A7.1 was lowly expressed in HCC, whose low expression was associated with large tumour size, aggressive clinical characteristic, and poor survival. Gain- and loss-of-function assays demonstrated that KB-68A7.1 restricted HCC cellular proliferation, induced HCC cellular apoptosis, and suppressed HCC cellular migration and invasion in vitro. Xenograft assays demonstrated that KB-68A7.1 suppressed HCC tumour growth and metastasis in vivo. These functional assays suggested KB-68A7.1 as a tumour suppressor in HCC. Histone methyltransferase nuclear receptor binding SET domain-containing protein 1 (NSD1) was found to bind to KB-68A7.1. KB-68A7.1 was mainly distributed in the cytoplasm. The binding of KB-68A7.1 to NSD1 sequestrated NSD1 in the cytoplasm, leading to the reduction in nuclear NSD1 level. Through decreasing nuclear NSD1 level, KB-68A7.1 reduced di-methylation of histone H3 at lysine 36 (H3K36me2) and increased tri-methylation of histone H3 at lysine 27 (H3K27me3) at the promoter of WNT10B, a target of NSD1. Thus, KB-68A7.1 repressed WNT10B transcription. The expression of WNT10B was negatively correlated with that of KB-68A7.1 in HCC tissues. Through repressing WNT10B, KB-68A7.1 further repressed Wnt/β-catenin signalling. Functional rescue assays showed that overexpression of WNT10B reversed the tumour-suppressive roles of KB-68A7.1, whereas the oncogenic roles of KB-68A7.1 depletion were abolished by Wnt/β-catenin signalling inhibitor. Overall, this study identified KB-68A7.1 as a lowly expressed and prognosis-related lncRNA in HCC, which suppressed HCC progression through binding to NSD1 and repressing Wnt/β-catenin signalling.

IGFBP7-AS1 is a p53-responsive long noncoding RNA downregulated by Epstein-Barr virus that contributes to viral tumorigenesis

Epstein-Barr virus (EBV) is closely related to the development of several malignancies, such as B-cell lymphoma (B-CL), by the mechanism through which these malignancies develop remains largely unknown. We previously observed downregulation of the long noncoding RNA (lncRNA) IGFBP7-AS1 in response to EBV infection. However, the role of IGFBP7-AS1 in EBV-associated cancers has not been clarified. Here, we found that expression of IGFBP7-AS1, as well as its sense gene IGFBP7, is decreased in EBV-positive B-CL cells and clinical tissues. IGFBP7-AS1 stabilizes IGFBP7 mRNA by forming a duplex based on their overlapping regions. The tumour suppressor p53 transcriptionally activates IGFBP7-AS1 expression by binding to the promoter region of the lncRNA gene. The IGFBP7-AS1 expression is able to be rescued in EBV-positive cells in wild-type (wt) p53-dependent manner. IGFBP7-AS1 inhibits the proliferation and promotes the apoptosis of B-CL cells. Moreover, tumorigenic properties due to the depletion of IGFBP7-AS1 were restored by exogenous expression of IGFBP7 or wt-p53. Furthermore, the functional p53/IGFBP7-AS1/IGFBP7 axis facilitates apoptosis by suppressing the production and secretion of the NPPB signal peptide and further regulating the cGMP-PKG signalling pathway. This study demonstrates that EBV promotes tumorigenesis, particularly in B-CL progression, by downregulating the novel p53-responsive lncRNA IGFBP7-AS1.

The Relationship Between the Network of Non-coding RNAs-Molecular Targets and N6-Methyladenosine Modification in Colorectal Cancer

Recent accumulating researches implicate that non-coding RNAs (ncRNAs) including microRNA (miRNA), circular RNA (circRNA), and long non-coding RNA (lncRNAs) play crucial roles in colorectal cancer (CRC) initiation and development. Notably, N6-methyladenosine (m⁶A) methylation, the critical posttranscriptional modulators, exerts various functions in ncRNA metabolism such as stability and degradation. However, the interaction regulation network among ncRNAs and the interplay with m⁶A-related regulators has not been well documented, particularly in CRC. Here, we summarize the interaction networks and sub-networks of ncRNAs in CRC based on a data-driven approach from the publications (IF > 6) in the last quinquennium (2016–2021). Further, we extend the regulatory pattern between the core m⁶A regulators and m⁶A-related ncRNAs in the context of CRC metastasis and progression. Thus, our review will highlight the clinical potential of ncRNAs and m⁶A modifiers as promising biomarkers and therapeutic targets for improving the diagnostic precision and treatment of CRC.

DNA-methylation-induced silencing of DIO3OS drives non-small cell lung cancer progression via activating hnRNPK-MYC-CDC25A axis

DNA methylation is a class of epigenetic modification manner, which is responsible for the inactivation of various tumor suppressors. Recently, long non-coding RNAs (lncRNAs) were revealed to be implicated in a variety of malignancies, including non-small cell lung cancer (NSCLC). However, the contributions of lncRNAs to DNA-methylation-induced oncogenic effects in NSCLC remain largely unknown. In this study, we identified a DNA-methylation-repressed lncRNA DIO3 opposite strand upstream RNA (DIO3OS) in NSCLC. DIO3OS is downregulated in NSCLC, and its low expression is related to poor prognosis. Ectopic expression of DIO3OS repressed NSCLC cell growth and motility and promoted NSCLC cell apoptosis in vitro. DIO3OS also repressed NSCLC tumorigenesis and metastasis in vivo. DIO3OS knockdown exhibited opposite biological effects. DIO3OS competitively bound heterogeneous nuclear ribonucleoprotein K (hnRNPK), repressed the binding of hnRNPK to MYC DNA and MYC mRNA, reduced the promoting roles of hnRNPK on MYC transcription and translation, led to the repression of MYC transcription and translation, and therefore remarkably decreased the expression of MYC and CDC25A, a downstream target of MYC. Additionally, depletion of hnRNPK blocked the tumor-suppressive roles of DIO3OS in NSCLC. In conclusion, these findings identified DIO3OS as an important protective factor against NSCLC via modulating hnRNPK-MYC-CDC25A axis.

ITGB1-DT/ARNTL2 axis may be a novel biomarker in lung adenocarcinoma: a bioinformatics analysis and experimental validation

BACKGROUND

Lung cancer is one of the most lethal malignant tumors that endangers human health. Lung adenocarcinoma (LUAD) has increased dramatically in recent decades, accounting for nearly 40% of all lung cancer cases. Increasing evidence points to the importance of the competitive endogenous RNA (ceRNA) intrinsic mechanism in various human cancers. However, behavioral characteristics of the ceRNA network in lung adenocarcinoma need further study.

METHODS

Groups based on SLC2A1 expression were used in this study to identify associated ceRNA networks and potential prognostic markers in lung adenocarcinoma. The Cancer Genome Atlas (TCGA) database was used to obtain the patients' lncRNA, miRNA, and mRNA expression profiles, as well as clinical data. Informatics techniques were used to investigate the effect of hub genes on prognosis. The Cox regression analyses were performed to evaluate the prognostic effect of hub genes. The methylation, GSEA, and immune infiltration analyses were utilized to explore the potential mechanisms of the hub gene. The CCK-8, transwell, and colony formation assays were performed to detect the proliferation and invasion of lung cancer cells.

RESULTS

We eventually identified the ITGB1-DT/ARNTL2 axis as an independent fact may promote lung adenocarcinoma progression. Furthermore, methylation analysis revealed that hypo-methylation may cause the dysregulated ITGB1-DT/ARNTL2 axis, and immune infiltration analysis revealed that the ITGB1-DT/ARNTL2 axis may affect the immune microenvironment and the progression of lung adenocarcinoma. The CCK-8, transwell, and colonu formation assays suggested that ITGB1-DT/ARNTL2 promotes the progression of lung adenocarcinoma. And hsa-miR-30b-3p reversed the ITGB1/ARNTL2-mediated oncogenic processes.

CONCLUSION

Our study identified the ITGB1-DT/ARNTL2 axis as a novel prognostic biomarker affects the prognosis of lung adenocarcinoma.

Long non-coding RNA HOMER3-AS1 drives hepatocellular carcinoma progression via modulating the behaviors of both tumor cells and macrophages

The crosstalk between cancer cells and tumor microenvironment plays critical roles in hepatocellular carcinoma (HCC). The identification of long non-coding RNAs (lncRNAs) mediating the crosstalk might promote the development of new therapeutic strategies against HCC. Here, we identified a lncRNA, HOMER3-AS1, which is over-expressed in HCC and correlated with poor survival of HCC patients. HOMER3-AS1 promoted HCC cellular proliferation, migration, and invasion, and reduced HCC cellular apoptosis. Furthermore, HOMER3-AS1 promoted macrophages recruitment and M2-like polarization. In vivo, HOMER3-AS1 significantly facilitated HCC progression. Mechanism investigations revealed that HOMER3-AS1 activated Wnt/β-catenin signaling via upregulating HOMER3. Functional rescue experiments revealed that HOMER3/Wnt/β-catenin axis mediated the roles of HOMER3-AS1 in promoting HCC cellular malignant phenotypes. Furthermore, colony stimulating factor-1 (CSF-1) was also identified as a critical downstream target of HOMER3-AS1. HOMER3-AS1 increased CSF-1 expression and secretion. Blocking CSF-1 reversed the roles of HOMER3-AS1 in inducing macrophages recruitment and M2 polarization. Furthermore, positive correlations between HOMER3-AS1 and HOMER3 expression, HOMER3-AS1 and CSF-1 expression, and HOMER3-AS1 expression and M2-like macrophages infiltration were found in human HCC tissues. In summary, our findings demonstrated that HOMER3-AS1 drives HCC progression via modulating the behaviors of both tumor cells and macrophages, which are dependent on the activation of HOMER3/Wnt/β-catenin axis and CSF-1, respectively. HOMER3-AS1 might be a promising prognostic and therapeutic target for HCC.

Long Non-Coding RNA: A Potential Strategy for the Diagnosis and Treatment of Colorectal Cancer

Colorectal cancer (CRC), being one of the most commonly diagnosed cancers worldwide, endangers human health. Because the pathological mechanism of CRC is not fully understood, there are many challenges in the prevention, diagnosis, and treatment of this disease. Long non-coding RNAs (lncRNAs) have recently drawn great attention for their potential roles in the different stages of CRC formation, invasion, and progression, including regulation of molecular signaling pathways, apoptosis, autophagy, angiogenesis, tumor metabolism, immunological responses, cell cycle, and epithelial-mesenchymal transition (EMT). This review aims to discuss the potential mechanisms of several oncogenic lncRNAs, as well as several suppressor lncRNAs, in CRC occurrence and development to aid in the discovery of new methods for CRC diagnosis, treatment, and prognosis assessment.

ADORA2A-AS1 Restricts Hepatocellular Carcinoma Progression via Binding HuR and Repressing FSCN1/AKT Axis

Background

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Increasing evidence revealed that long noncoding RNAs (lncRNAs) were frequently involved in various malignancies. Here, we explored the clinical significances, roles, and mechanisms of lncRNA ADORA2A antisense RNA 1 (ADORA2A-AS1) in HCC.

Methods

The clinical significances of ADORA2A-AS1 in HCC were analyzed using RNA sequencing (RNA-seq) data from The Cancer Genome Atlas (TCGA) project. The expressions of ADORA2A-AS1, Fascin Actin-Bundling Protein 1 (FSCN1), Matrix Metallopeptidase 2 (MMP2), and Baculoviral IAP Repeat Containing 7 (BIRC7) in HCC tissues and cells were measured by qRT-PCR. Cell Counting Kit-8 (CCK-8), 5-ethynyl-2’-deoxyuridine (EdU), caspase-3 activity assay, transwell migration and invasion assays, and xenograft growth and metastasis experiments were performed to evaluate the roles of ADORA2A-AS1 in HCC. RNA pull-down, RNA immunoprecipitation, qRT-PCR, Western blot, and RNA stability assay were performed to elucidate the mechanisms of ADORA2A-AS1 in HCC.

Results

ADORA2A-AS1 was identified as an HCC-related lncRNA, whose low expression was correlated with advanced stage and poor outcome in HCC. Gain- and loss-of functional experiments demonstrated that ADORA2A-AS1 inhibited HCC cell proliferation, induced cell apoptosis, repressed cell migration and invasion, and repressed xenograft growth and metastasis in vivo. Mechanistically, ADORA2A-AS1 competitively bound HuR (Hu Antigen R), repressed the binding of HuR to FSCN1 transcript, decreased FSCN1 transcript stability, and downregulated FSCN1 expression. The expression of FSCN1 was negatively correlated with ADORA2A-AS1 in HCC tissues. Through downregulating FSCN1, ADORA2A-AS1 repressed AKT pathway activation. Functional rescue assays showed that blocking of FSCN1/AKT axis abrogated the roles of ADORA2A-AS1 in HCC.

Conclusion

Low-expression ADORA2A-AS1 is correlated with poor survival of HCC patients. ADORA2A-AS1 exerts tumor-suppressive roles in HCC via binding HuR and repressing FSCN1/AKT axis.

Metastatic colorectal cancer: Perspectives on long non-coding RNAs and promising therapeutics

Metastatic colorectal cancer (mCRC) has long been lethal despite the continuous efforts of researchers worldwide to discover and improve therapeutic regimens. Thanks to the emergence of long non-coding RNAs (lncRNAs), which has strongly reshaped our inherent perspectives on the pathophysiological patterns of disease, research in the field has been reinvigorated. Here, we focus on current understanding of the modes of action of lncRNAs, and review their regulatory roles in metastatic colorectal cancer, and discuss correlated potential lncRNA-based therapeutics. All of the discussed studies share clear and promising perspectives on future diagnostic and therapeutic remedies for metastatic colorectal cancer.

LBX2-AS1 as a Novel Diagnostic Biomarker and Therapeutic Target Facilitates Multiple Myeloma Progression by Enhancing mRNA Stability of LBX2

Objective: Multiple myeloma (MM) represents a common age-associated malignancy globally. The function and underlying mechanism of antisense lncRNA LBX2-AS1 remain ambiguous in multiple myeloma (MM). Herein, we aimed to observe the biological implication of this lncRNA in MM.

Methods: RT-qPCR was employed to examine circulating LBX2-AS1 and LBX2 in 60 paired MM and healthy subjects. Correlation between the two was analyzed by Pearson test. Under transfection with shLBX2-AS1, proliferation and apoptosis were evaluated in MM cells through CCK-8, colony formation and flow cytometry. LBX2 expression was examined in MM cells with shLBX2-AS1 or pcDNA3.1-LBX2 transfection. Following treatment with cycloheximide or actinomycin D, LBX2 expression was examined in pcDNA3.1-LBX2-transfected MM cells at different time points. Rescue assays were then presented. Finally, xenograft tumor models were established.

Results: Circulating LBX2-AS1 was up-regulated in MM patients and positively correlated to LBX2 expression. Area under the curve (AUC) of LBX2-AS1 expression was 0.7525. Its up-regulation was also found in MM cells and primarily distributed in cytoplasm. LBX2-AS1 knockdown distinctly weakened proliferative ability and induced apoptosis in MM cells. Overexpressing LBX2-AS1 markedly strengthened LBX2 expression by increasing its mRNA stability. Rescue assays showed that silencing LBX2-AS1 distinctly weakened the pcDNA3.1-LBX2-induced increase in proliferation and decrease in apoptosis for MM cells. Silencing LBX2-AS1 markedly weakened tumor growth.

Conclusion: Our data demonstrated that circulating LBX2-AS1 could be an underlying diagnostic marker in MM. Targeting LBX2-AS1 suppressed tumor progression by affecting mRNA stability of LBX2 in MM. Hence, LBX2-AS1 could be a novel therapeutic marker against MM.

Keep your eyes peeled for long noncoding RNAs: Explaining their boundless role in cancer metastasis, drug resistance, and clinical application

Cancer metastasis and drug resistance are two major obstacles in the treatment of cancer and therefore, the leading cause of cancer-associated mortalities worldwide. Hence, an in-depth understanding of these processes and identification of the underlying key players could help design a better therapeutic regimen to treat cancer. Earlier thought to be merely transcriptional junk and having passive or secondary function, recent advances in the genomic research have unravelled that long noncoding RNAs (lncRNAs) play pivotal roles in diverse physiological as well as pathological processes including cancer metastasis and drug resistance. LncRNAs can regulate various steps of the complex metastatic cascade such as epithelial-mesenchymal transition (EMT), invasion, migration and metastatic colonization, and also affect the sensitivity of cancer cells to various chemotherapeutic drugs. A substantial body of literature for more than a decade of research evince that lncRNAs can regulate gene expression at different levels such as epigenetic, transcriptional, posttranscriptional, translational and posttranslational levels, depending on their subcellular localization and through their ability to interact with DNA, RNA and proteins. In this review, we mainly focus on how lncRNAs affect cancer metastasis by modulating expression of key metastasis-associated genes at various levels of gene regulation. We also discuss how lncRNAs confer cancer cells either sensitivity or resistance to various chemo-therapeutic drugs via different mechanisms. Finally, we highlight the immense potential of lncRNAs as prognostic and diagnostic biomarkers as well as therapeutic targets in cancer.

Long non-coding RNA RP11-283G6.5 confines breast cancer development through modulating miR-188-3p/TMED3/Wnt/β-catenin signalling

The contributions of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) to breast cancer are critical areas of investigation. In this study, we identified a novel lncRNA RP11-283G6.5 which was lowly expressed in breast cancer and whose low expression was correlated with poor overall survival and disease-free survival of breast cancer patients. Functional experiments revealed that ectopic expression of RP11-283G6.5 confined breast cancer cellular growth, migration, and invasion, and promoted cellular apoptosis. Conversely, RP11-283G6.5 silencing facilitated breast cancer cellular growth, migration, and invasion, and repressed cellular apoptosis. Moreover, RP11-283G6.5 was found to confine breast cancer tumour growth and metastasis in vivo. Mechanistically, RP11-283G6.5 competitively bound to ILF3, reduced the binding of ILF3to primary miR-188 (pri-miR-188), abolished the suppressive effect of ILF3 on pri-miR-188 processing, and therefore promoted pri-miR-188 processing, leading to the reduction of pri-miR-188 and the upregulation of mature miR-188-3p. The expression of RP11-283G6.5 was significantly positively correlated with that of miR-188-3p in breast cancer tissues. Through increasing miR-188-3p, RP11-283G6.5 decreased TMED3, a target of miR-188-3p. RP11-283G6.5 further suppressed Wnt/β-catenin signalling via decreasing TMED3. Rescue assays revealed that inhibition of miR-188-3p, overexpression of TMED3 or blocking Wnt/β-catenin signalling all attenuated the roles of RP11-283G6.5 in breast cancer. Collectively, these findings demonstrated that RP11-283G6.5 is a tumour suppressive lncRNA in breast cancer via modulating miR-188-3p/TMED3/Wnt/β-catenin signalling. This study indicated that RP11-283G6.5 might be a promising prognostic biomarker and therapeutic target for breast cancer.

SPINT1-AS1 Drives Cervical Cancer Progression via Repressing miR-214 Biogenesis

Accumulating evidences have revealed the dysregulated expressions and critical roles of non-coding RNAs in various malignancies, including cervical cancer. Nevertheless, our knowledge about the vast majority of non-coding RNAs is still lacking. Here we identified long non-coding RNA (lncRNA) SPINT1-AS1 as a novel cervical cancer-associated lncRNA. SPINT1-AS1 was increased in cervical cancer and correlated with advanced stage and poor prognosis. SPINT1-AS1 was a direct downstream target of miR-214, a well-known tumor suppressive microRNA (miRNA) in cervical cancer. Intriguingly, SPINT1-AS1 was also found to repress miR-214 biogenesis via binding DNM3OS, the primary transcript of miR-214. The interaction between SPINT1-AS1 and DNM3OS repressed the binding of DROSHA and DGCR8 to DNM3OS, blocked DNM3OS cleavage, and therefore repressed mature miR-214 biogenesis. The expression of SPINT1-AS1 was significantly negatively correlated with miR-214 in cervical cancer tissues, supporting the reciprocal repression between SPINT1-AS1 and miR-214 in vivo. Through downregulating mature miR-214 level, SPINT1-AS1 upregulated the expression of β-catenin, a target of miR-214. Thus, SPINT1-AS1 further activated Wnt/β-catenin signaling in cervical cancer. Functionally, SPINT1-AS1 drove cervical cancer cellular proliferation, migration, and invasion in vitro, and also tumorigenesis in vivo. Deletion of the region mediating the interaction between SPINT1-AS1 and DNM3OS, overexpression of miR-214, and inhibition of Wnt/β-catenin signaling all reversed the roles of SPINT1-AS1 in cervical cancer. Collectively, these findings identified SPINT1-AS1 as a novel cervical cancer-associated oncogenic lncRNA which represses miR-214 biogenesis and activates Wnt/β-catenin signaling, highlighting its potential as prognostic biomarker and therapeutic target for cervical cancer.

RP11-51O6.1 sponges miR-206 to accelerate colorectal cancer carcinogenesis and metastasis through upregulating YAP1

Long non-coding RNAs (lncRNAs) have been characterized by playing a crucial role in tumorigenesis. However, the detail biological function and clinical importance of lncRNAs in colorectal cancer (CRC) are unclear and have attracted different levels of in-depth research. In this context, we explored the differentially expressed profiles of lncRNAs in six CRC tissues and three adjacent non-tumor tissues from RNA-sequencing (RNA-seq) study and noted a lncRNA, RP11-51O6.1, which is markedly overexpressed in CRC tissues, particularly in aggressive cases. Impressively, an elevated RP11-51O6.1 level was highly correlated with poor prognosis in clinical patients. Functional analyses revealed that RP11-51O6.1 could promote cell proliferation in vitro and in vivo. Furthermore, we reported that RP11-51O6.1 enhances cell migration and invasion in vitro. Mechanistic studies (Bioinformatics binding site analyses, the Luciferase reporter, Ago2 immunoprecipitation, the RNA pull-down, immunofluorescence colocalization, rescued assays and western blotting) implicated that RP11-51O6.1 could regulate YAP1 expression by competitively sponging miR-206 and blocking its activity in promoting CRC progression. Conclusively, our findings identify a novel RP11-51O6.1/miR-206/YAP1 regulatory axis that participates in CRC progression and development, suggesting RP11-51O6.1 is an exploitable biomarker and appealing therapeutic target in treating CRC.

FUT8-AS1 Inhibits the Malignancy of Melanoma Through Promoting miR-145-5p Biogenesis and Suppressing NRAS/MAPK Signaling

Melanoma is the major lethal skin malignancy. However, the critical molecular drivers governing melanoma progression and prognosis are still not clear. By analyzing The Cancer Genome Atlas (TCGA) data, we identified FUT8-AS1 as a prognosis-related long non-coding RNA (lncRNA) in melanoma. We further confirmed that FUT8-AS1 is downregulated in melanoma. Reduced expression of FUT8-AS1 is correlated with aggressive clinical factors and inferior overall survival. Using in vitro functional assays, our findings demonstrated that ectopic expression of FUT8-AS1 represses melanoma cell proliferation, migration, and invasion. FUT8-AS1 silencing promotes melanoma cell proliferation, migration, and invasion. Furthermore, in vivo functional assays demonstrated that FUT8-AS1 represses melanoma growth and metastasis. Mechanistically, FUT8-AS1 was found to bind NF90, repress the interaction between NF90 and primary miR-145 (pri-miR-145), relieve the repressive roles of NF90 on mature miR-145-5p biogenesis, and thus promote miR-145-5p biogenesis and upregulate mature miR-145-5p level. The expression of FUT8-AS1 is positively correlated with miR-145-5p in melanoma tissues. Via upregulating miR-145-5p, FUT8-AS1 reduces the expression of NRAS, a target of miR-145-5. FUT8-AS1 further represses MAPK signaling via downregulating NRAS. Functional rescue assays demonstrated that inhibition of miR-145-5p reverses the tumor suppressive roles of FUT8-AS1 in melanoma. The oncogenic roles of FUT8-AS1 silencing are also blocked by MAPK signaling inhibitor MEK162. In conclusion, these findings demonstrate that FUT8-AS1 exerts tumor suppressive roles in melanoma via regulating NF90/miR-145-5p/NRAS/MAPK signaling axis. Targeting FUT8-AS1 and its downstream molecular signaling axis represent promising therapeutic strategies for melanoma.

Reference-free transcriptome signatures for prostate cancer prognosis

BACKGROUND

RNA-seq data are increasingly used to derive prognostic signatures for cancer outcome prediction. A limitation of current predictors is their reliance on reference gene annotations, which amounts to ignoring large numbers of non-canonical RNAs produced in disease tissues. A recently introduced kind of transcriptome classifier operates entirely in a reference-free manner, relying on k-mers extracted from patient RNA-seq data.

METHODS

In this paper, we set out to compare conventional and reference-free signatures in risk and relapse prediction of prostate cancer. To compare the two approaches as fairly as possible, we set up a common procedure that takes as input either a k-mer count matrix or a gene expression matrix, extracts a signature and evaluates this signature in an independent dataset.

RESULTS

We find that both gene-based and k-mer based classifiers had similarly high performances for risk prediction and a markedly lower performance for relapse prediction. Interestingly, the reference-free signatures included a set of sequences mapping to novel lncRNAs or variable regions of cancer driver genes that were not part of gene-based signatures.

CONCLUSIONS

Reference-free classifiers are thus a promising strategy for the identification of novel prognostic RNA biomarkers.

LncRNA signature in colorectal cancer

Colorectal cancer (CRC) is among the most frequent cancers and is associated with high mortality particularly when being diagnosed in advanced stages. Although several environmental and intrinsic risk factors have been identified, the underlying cause of CRC is not clear in the majority of cases. Several studies especially in the recent decade have pointed to the role of epigenetic factors in this kind of cancer. Long non-coding RNAs (lncRNAs) as important contributors in the epigenetic mechanisms are involved in the initiation, progression and metastasis of CRC. Tens of oncogenic lncRNAs and a lower number of tumor suppressor lncRNAs have been recently identified to be dysregulated in CRC cells and tissues. Notably, expressions of a number of these transcripts have been dysregulated in serum samples of CRC patients, providing a non-invasive route for detection of this kind of cancer. The involvement of lncRNAs in the regulation of autophagy has provided them the ability to modulate response of CRC cells to chemotherapeutic modalities. In the current manuscript, we review the studies which evaluated the role of lncRNAs in the pathogenesis and progression of CRC to appraise their application as diagnostic/ prognostic markers.

ITGB1-DT Facilitates Lung Adenocarcinoma Progression via Forming a Positive Feedback Loop With ITGB1/Wnt/β-Catenin/MYC

Lung adenocarcinoma (LUAD) is the main histological type of lung cancer, which is the leading cause of cancer-related deaths. Long non-coding RNAs (lncRNAs) were recently revealed to be involved in various cancers. However, the clinical relevance and potential biological roles of most lncRNAs in LUAD remain unclear. Here, we identified a prognosis-related lncRNA ITGB1-DT in LUAD. ITGB1-DT was upregulated in LUAD and high expression of ITGB1-DT was correlated with advanced clinical stages and poor overall survival and disease-free survival. Enhanced expression of ITGB1-DT facilitated LUAD cellular proliferation, migration, and invasion, and also lung metastasis in vivo. Knockdown of ITGB1-DT repressed LUAD cellular proliferation, migration, and invasion. ITGB1-DT interacted with EZH2, repressed the binding of EZH2 to ITGB1 promoter, reduced H3K27me3 levels at ITGB1 promoter region, and therefore activated ITGB1 expression. Through upregulating ITGB1, ITGB1-DT activated Wnt/β-catenin pathway and its downstream target MYC in LUAD. The expressions of ITGB1-DT, ITGB1, and MYC were positively correlated with each other in LUAD tissues. Intriguingly, ITGB1-DT was found as a transcriptional target of MYC. MYC directly transcriptionally activated ITGB1-DT expression. Thus, ITGB1-DT formed a positive feedback loop with ITGB1/Wnt/β-catenin/MYC. The oncogenic roles of ITGB1-DT were reversed by depletion of ITGB1 or inhibition of Wnt/β-catenin pathway. In summary, these findings revealed ITGB1-DT as a prognosis-related and oncogenic lncRNA in LUAD via activating the ITGB1-DT/ITGB1/Wnt/β-catenin/MYC positive feedback loop. These results implicated ITGB1-DT as a potential prognostic biomarker and therapeutic target for LUAD.

KLHDC7B-DT aggravates pancreatic ductal adenocarcinoma development via inducing cross-talk between cancer cells and macrophages

Tumor microenvironment (TME) exerts key roles in pancreatic ductal adenocarcinoma (PDAC) development. However, the factors regulating the cross-talk between PDAC cells and TME are largely unknown. In the present study, we identified a long noncoding RNA (lncRNA) KLHDC7B divergent transcript (KLHDC7B-DT), which was up-regulated in PDAC and correlated with poor survival of PDAC patients. Functional assays demonstrated that KLHDC7B-DT enhanced PDAC cell proliferation, migration, and invasion. Mechanistically, KLHDC7B-DT was found to directly bind IL-6 promoter, induce open chromatin structure at IL-6 promoter region, activate IL-6 transcription, and up-regulate IL-6 expression and secretion. The expression of KLHDC7B-DT was positively correlated with IL-6 in PDAC tissues. Via inducing IL-6 secretion, KLHDC7B-DT activated STAT3 signaling in PDAC cells in an autocrine manner. Furthermore, KLHDC7B-DT also activated STAT3 signaling in macrophages in a paracrine manner, which induced macrophage M2 polarization. KLHDC7B-DT overexpressed PDAC cells-primed macrophages promoted PDAC cell proliferation, migration, and invasion. Blocking IL-6/STAT3 signaling reversed the effects of KLHDC7B-DT on macrophage M2 polarization and PDAC cell proliferation, migration, and invasion. In conclusion, KLHDC7B-DT enhanced malignant behaviors of PDAC cells via IL-6-induced macrophage M2 polarization and IL-6-activated STAT3 signaling in PDAC cells. The cross-talk between PDAC cells and macrophages induced by KLHDC7B-DT represents potential therapeutic target for PDAC.

The Emerging Landscape of Long Non-Coding RNAs in Colorectal Cancer Metastasis

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers, with extremely high rates of morbidity and mortality. The main cause of death in CRC is distant metastasis; it affects patient prognosis and survival and is one of the key challenges in the treatment of CRC. Long non-coding RNAs (lncRNAs) are a group of non-coding RNA molecules with more than 200 nucleotides. Abnormal lncRNA expression is closely related to the occurrence and progression of several diseases, including cancer. Recent studies have shown that numerous lncRNAs play pivotal roles in the CRC metastasis, and reversing the expression of these lncRNAs through artificial means can reduce the malignant phenotype of metastatic CRC to some extent. This review summarizes the major mechanisms of lncRNAs in CRC metastasis and proposes lncRNAs as potential therapeutic targets for CRC and molecular markers for early diagnosis.

Crosstalk of long non-coding RNAs and EMT: Searching the missing pieces of an incomplete puzzle for lung cancer therapy

BACKGROUND

Lung cancer is considered to be the first place among the cancer-related deaths worldwide and demands novel strategies in the treatment of this life-threatening disorder. The aim of this review is to explore regulation of epithelial-to-mesenchymal transition (EMT) by long non-coding RNAs (lncRNAs) in lung cancer.

INTRODUCTION

LncRNAs can be considered as potential factors for targeting in cancer therapy, since they regulate a bunch of biological processes, e.g. cell proliferation, differentiation and apoptosis. The abnormal expression of lncRNAs occurs in different cancer cells. On the other hand, epithelial-to-mesenchymal transition (EMT) is a critical mechanism participating in migration and metastasis of cancer cells.

METHOD

Different databases including Googlescholar, Pubmed and Sciencedirect were used for collecting articles using keywords such as "LncRNA", "EMT", and "Lung cancer".

RESULT

There are tumor-suppressing lncRNAs that can suppress EMT and metastasis of lung cancer cells. Expression of such lncRNAs undergoes down-regulation in lung cancer progression and restoring their expression is of importance in suppressing lung cancer migration. There are tumor-promoting lncRNAs triggering EMT in lung cancer and enhancing their migration.

CONCLUSION

LncRNAs are potential regulators of EMT in lung cancer, and targeting them, both pharmacologically and genetically, can be of importance in controlling migration of lung cancer cells.

LINC01116 facilitates colorectal cancer cell proliferation and angiogenesis through targeting EZH2-regulated TPM1

BACKGROUND

Colorectal cancer (CRC) is a common malignant tumor globally. Meanwhile, LINC01116 has been proposed as risk factor for various tumors, including CRC. But the regulation of LINC01116 in CRC required more validated data. This study aimed to elucidate the potential function of LINC01116 in regulating cell proliferation and angiogenesis of CRC.

METHODS

LINC01116 expression in 80 pairs of CRC tumor and adjacent non-tumor tissues was determined by qRT-PCR. After transfection of pcDNA3.1-LINC01116, sh-LINC01116, sh-TPM1, pcDNA3.1-EZH2 or sh-EZH2 in SW480 and HCT116 cells, the levels of LINC01116, TPM1 and EZH2 were measured by qRT-PCR or Western blot. The cell biological function of CRC cell lines was determined by CCK-8, colony formation assays, tube formation and scratch assays. RNA pull-down and RIP assays were applied to detect the binding of LINC01116 with EZH2 and H3K27me3. Binding of EZH2 to the TPM1 promoter was assessed by ChIP assay. Finally, xenograft models in nude mice were established to validate the results of in vitro experiments.

RESULTS

LINC01116 was overexpressed in CRC tissues and high expression of LINC01116 was negatively correlated with postoperative survival. In vitro study showed LINC01116 expression could significantly enhance CRC progression, including increasing cell proliferation, migration and angiogenesis. Besides, investigations into the mechanism disclosed that LINC01116 could regulate EZH2 to inactivate TPM1 promoter, thus promoting CRC cell proliferation and angiogenesis. Moreover, consistent results of in vivo experiments were conformed in vitro experiments.

CONCLUSION

LINC01116 promotes the proliferation and angiogenesis of CRC cells by recruiting EZH2 to potentiate methylation in the TPM1 promoter region to inhibit the transcription of TPM1.

lncRNA MCM3AP-AS1 inhibits the progression of colorectal cancer via the miR-19a-3p/FOXF2 axis

BACKGROUND

Long non-coding RNA MCM3AP antisense RNA 1 (lncRNA MCM3AP-AS1) has a regulatory role in the development of diverse malignancies, whereas its role and mechanism in colorectal cancer (CRC) is not yet clear.

METHODS

The relative expression of MCM3AP-AS1, miR-19a-3p and forkhead box F2 (FOXF2) mRNA in 53 cases of CRC and its adjacent normal tissues, human normal colonic mucosal cells (FHC cells) and CRC cell lines was examined by a quantitative real-time polymerase chain reaction, and the changes of cell multiplication and migration were examined by the cell counting kit-8 method, EdU test, and scratch-healing test, respectively. Bioinformatics, dual-luciferase reporter gene assay and a RNA immunoprecipitation experiment were adopted to predict and verify the relationship between MCM3AP-AS1 and miR-19a-3p; bioinformatics and dual-luciferase reporter gene assay were adopted to predict and verify the relationship between miR-19a-3p and FOXF2. Western blotting was executed to examine the effects of MCM3AP-AS1 overexpression or knockdown on FOXF2 protein expression.

RESULTS

MCM3AP-AS1 expression was down-modulated in CRC, and its dysregulation was linked to unfavorable pathological characteristics. MCM3AP-AS1 significantly impeded the multiplication and migration of CRC cells. MCM3AP-AS1 was recognized as a molecular sponge to suppress miR-19a-3p expression, and FOXF2 was a target gene of miR-19a-3p. MCM3AP-AS1 positively modulated FOXF2 expression, and its biological effect was dependent the on miR-19a-3p/FOXF2 axis.

CONCLUSIONS

MCM3AP-AS1 can inhibit CRC promoting by modulating the miR-19a-3p/FOXF2 axis.

Comprehensive analysis of lncRNA-associated ceRNA network reveals the novel potential of lncRNA, miRNA and mRNA biomarkers in human rectosigmoid junction cancer

Although accumulating evidence has confirmed the potential biological functions of long non-coding RNAs (lncRNAs) as competitive endogenous RNAs (ceRNAs) in colorectal tumorigenesis and progression, few studies have focused on rectosigmoid junction cancer. In the present study, a comprehensive analysis was conducted to explore lncRNA-mediated ceRNA implications and their potential value for prognosis. lncRNA, microRNA (miR/miRNA) and mRNA expression profiles were downloaded from The Cancer Genome Atlas database. Subsequently, a lncRNA-miRNA-mRNA regulatory network was constructed to evaluate the functions of these differentially expressed genes on overall survival (OS) for rectosigmoid junction cancer. As a result, a rectosigmoid junction cancer-specific ceRNA network was successfully constructed with 7 differentially expressed (DE)lncRNAs, 16 DEmiRNAs and 71 DEmRNAs. Among the network, one DElncRNA (small nucleolar RNA host gene 20) and three mRNAs (sodium- and chloride-dependent taurine transporter, fibroblast growth factor 13 and tubulin polyglutamylase TTLL7) were significantly associated with OS (P<0.05). Additionally, two lncRNAs (KCNQ1OT1 and MIR17HG) interacted with most of the DEmiRNAs. Notably, two top-ranked miRNAs (hsa-miR-374a-5p and hsa-miR-374b-5p) associated networks were identified to be markedly associated with the pathogenesis. Furthermore, four DEmRNAs (caveolin-1, MET, filamin-A and AKT3) were enriched in the Kyoto Encylopedia of Gene and Genomes pathway analysis, as well as being included in the ceRNA network. In summary, the present results revealed that a specific lncRNA-miRNA-mRNA network was associated with rectosigmoid junction cancer, providing several molecules that may be used as novel prognostic biomarkers and therapeutic targets.

Regulation of melanoma malignancy by the RP11-705C15.3/miR-145-5p/NRAS/MAPK signaling axis

Melanoma is a common lethal skin cancer. Dissecting molecular mechanisms driving the malignancy of melanoma may uncover potential therapeutic targets. We previously identified miR-145-5p as an important tumor-suppressive microRNA in melanoma. Here, we further investigated the roles of long non-coding RNAs (lncRNAs) in melanoma. We identified RP11-705C15.3, a regulator of miR-145-5p, as an oncogenic lncRNA in melanoma. RP11-705C15.3 competitively bound miR-145-5p, relieved the repressive roles of miR-145-5p on its target NRAS, upregulated NRAS expression, and activated MAPK signaling. In vitro functional assays revealed that ectopic expression of RP11-705C15.3 promoted melanoma cell proliferation, inhibited apoptosis, and promoted migration and invasion. Silencing of RP11-705C15.3 repressed melanoma cell proliferation, induced apoptosis, and repressed migration and invasion. Notably, the roles of RP11-705C15.3 in melanoma cell proliferation, apoptosis, migration and invasion are reversed by miR-145-5p overexpression. In vivo functional assays revealed that RP11-705C15.3 promoted melanoma tumor growth and metastasis, which were also reversed by miR-145-5p overexpression. Furthermore, we investigated the expression of RP11-705C15.3 in clinical melanoma tissues and found that RP11-705C15.3 was increased in melanoma tissues. High expression of RP11-705C15.3 was positively correlated with thickness, ulceration, metastasis, and inferior overall survival. Taken together, our findings suggest RP11-705C15.3 as a novel oncogene in melanoma, and highlight that the RP11-705C15.3/miR-145-5p/NRAS/MAPK signaling axis may be potential therapeutic targets for melanoma.

LncRNA LINC00998 inhibits the malignant glioma phenotype via the CBX3-mediated c-Met/Akt/mTOR axis

Long noncoding RNAs (lncRNAs), once considered to be nonfunctional relics of evolution, are emerging as essential genes in tumor progression. However, the function and underlying mechanisms of lncRNAs in glioma remain unclear. This study aimed to investigate the role of LINC00998 in glioma progression. Through screening using TCGA database, we found that LINC00998 was downregulated in glioblastoma tissues and that low expression of LINC00998 was associated with poor prognosis. Overexpression of LINC00998 inhibited glioma cell proliferation in vitro and in vivo and blocked the G1/S cell cycle transition, which exerted a tumor-suppressive effect on glioma progression. Mechanistically, RNA pull-down and mass spectrometry results showed an interaction between LINC00998 and CBX3. IP assays demonstrated that LINC00998 could stabilize CBX3 and prevent its ubiquitination degradation. GSEA indicated that LINC00998 could regulate the c-Met/Akt/mTOR signaling pathway, which was further confirmed by a rescue assay using siRNA-mediated knockdown of CBX3 and the Akt inhibitor MK2206. In addition, dual-luciferase assays showed that miR-34c-5p could directly bind to LINC00998 and downregulate its expression. Our results identified LINC00998 as a novel tumor suppressor in glioma, and LINC00998 could be a novel prognostic biomarker, providing a strategy for precision therapy in glioma patients.

Long noncoding RNA LINC01578 drives colon cancer metastasis through a positive feedback loop with the NF-κB/YY1 axis

Metastasis accounts for poor prognosis of cancers and related deaths. Accumulating evidence has shown that long noncoding RNAs (lncRNAs) play critical roles in several types of cancer. However, which lncRNAs contribute to metastasis of colon cancer is still largely unknown. In this study, we found that lncRNA LINC01578 was correlated with metastasis and poor prognosis of colon cancer. LINC01578 was upregulated in colon cancer, associated with metastasis, advanced clinical stages, poor overall survival, disease-specific survival, and disease-free survival. Gain-of-function and loss-of-function assays revealed that LINC01578 enhanced colon cancer cell viability and mobility in vitro and colon cancer liver metastasis in vivo. Mechanistically, nuclear factor kappa B (NF-κB) and Yin Yang 1 (YY1) directly bound to the LINC01578 promoter, enhanced its activity, and activated LINC01578 expression. LINC01578 was shown to be a chromatin-bound lncRNA, which directly bound NFKBIB promoter. Furthermore, LINC01578 interacted with and recruited EZH2 to NFKBIB promoter and further repressed NFKBIB expression, thereby activating NF-κB signaling. Through activation of NF-κB, LINC01578 further upregulated YY1 expression. Through activation of the NF-κB/YY1 axis, LINC01578 in turn enhanced its own promoter activity, suggesting that LINC01578 and NF-κB/YY1 formed a positive feedback loop. Blocking NF-κB signaling abolished the oncogenic roles of LINC01578 in colon cancer. Furthermore, the expression levels of LINC01578, NFKBIB, and YY1 were correlated in clinical tissues. Collectively, this study demonstrated that LINC01578 promoted colon cancer metastasis via forming a positive feedback loop with NF-κB/YY1 and suggested that LINC01578 represents a potential prognostic biomarker and therapeutic target for colon cancer metastasis.