The long noncoding RNA CASC9 regulates migration and invasion in esophageal cancer

The long intergenic non-coding RNA LINC01140 modulates gastric cancer phenotypes and cancer cell lines aggressiveness

BACKGROUND

Long-intergenic non-protein coding gene 01140 (LINC01140) a long non-coding RNA is highly expressed in various cancers. However, its biological functions in gastric cancer progression is still unknown.

METHOD

To elucidate LINC01140 function, 70 GC tumor samples and 30 normal gastric tissues were collected. LINC01140 expression level were determined by qRT-PCR analysis and correlated with different clinico-pathological parameters. Then we tried to see the impact of LINC01140 on gastric cell line aggressiveness by knocking down the target gene and performing cell viability assay, migration assay and invasive capacity of the cell lines along with immunoblotting to check several protein levels.

RESULT

LINC01140 RNA is found to be positively correlated with FGF9 and significantly up regulated in GC tissues. LINC01140 knockdown inhibited the viability, migratory capacity and invasive capacity of AGS cells. LINC01140 targets miR-140-5p, while miR-140-5p targeted FGF9 to form lncRNA-miRNA-mRNA axis. The affect of miR-140-5p inhibition on gastric cancer cell aggressiveness were opposite to those of LINC01140 or FGF9 knockdown. Additionally, inhibition partially reversed the effects of LINC01140 knockdown on FGF9 protein levels, gastric cancer cell phenotypes.

CONCLUSION

LINC01140, miR-140-5p and FGF9 form a lncRNA-miRNA-mRNA axis that modulates the gastric cancer phenotypes and in turn affects gastric cancer cell aggressiveness.

Identification of a ceRNA Network Driven by Copy Number Variations in Esophageal Cancer

BACKGROUND

Copy number variation (CNV) is associated with progression of esophageal cancer (EC), a common gastrointestinal neoplasm.

METHODS

Using sequencing data, CNV data, and clinical data of EC transcriptome samples obtained from public databases, we performed differential expression analysis on sequencing data. Differentially expressed CNV-driven lncRNAs were screened using the chi-square test, and CNV-driven lncRNA-associated miRNAs and mRNAs were predicted. Cytoscape software was then used to construct ceRNA networks. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to investigate biological functions of mRNAs in the ceRNA network. Survival curves were plotted to explore correlations between lncRNAs in the ceRNA network and overall survival of CNV patients. Multiple databases were used to predict lncRNAs-related drugs.

RESULTS

A dysregulated lncRNA-associated ceRNA network driven by CNV in EC, including 11 lncRNAs, 11 miRNAs and 159 mRNAs, was constructed. Downstream enrichment of mRNAs was related to biological processes such as extracellular matrix organization, indicating that these mRNAs mainly participate in intercellular exchange between tumor cells. Additionally, expression of all lncRNAs in the ceRNA network, except LINC00950, LINC01270 and MIR181A1HG, was correlated with patients' CNV. In addition, none of the 11 lncRNAs was significantly correlated with overall survival of CNV patients. CH5424802 and PD-033299CNV mainly affected the RTK signaling pathway and the cell cycle of tumor cells via RP11-180N14.1 and RP11-273 G15.2 in the ceRNA network.

CONCLUSIONS

This study identified 11 CNV-driven lncRNAs that might affect EC development, 2 of which have promising effects if applied to drug treatment. These findings might assist in identifying novel treatments for EC.

lncRNA-mediated ceRNA network in bladder cancer

Bladder cancer is a common disease associated with high rates of morbidity and mortality. Although immunotherapy approaches such as adoptive T-cell therapy and immune checkpoint blockade have been investigated for the treatment of bladder cancer, their off-target effects and ability to affect only single targets have led to clinical outcomes that are far from satisfactory. Therefore, it is important to identify novel targets that can effectively control tumor growth and metastasis. It is well known that long noncoding RNAs (lncRNAs) are powerful regulators of gene expression. Increasing evidence has shown that dysregulated lncRNAs in bladder cancer are involved in cancer cell proliferation, migration, invasion, apoptosis, and epithelial-mesenchymal transition (EMT). In this review, we focus on the roles and underlying mechanisms of lncRNA-mediated competing endogenous RNA (ceRNA) networks in the regulation of bladder cancer progression. In addition, we discuss the potential of targeting lncRNA-mediated ceRNA networks to overcome cancer treatment resistance and its association with clinicopathological features and outcomes in bladder cancer patients. We hope this review will stimulate research to develop more effective therapeutic approaches for bladder cancer treatment.

LncRNA CASC9 promotes cell proliferation and invasion in osteosarcoma through targeting miR-874-3p/SOX12 axis

BACKGROUND

Osteosarcoma (OS) is a common primary malignant bone tumor. This study aimed to explore the biological role of long on-coding RNA (lncRNA) CASC9 and its regulatory mechanism in OC.

METHODS

The CASC9 expressions in OS cells and tissues were measured using qRT-PCR. The functional role of CASC9 in OC was studied using MTT assay, colony formation assay, transwell invasion assay, and xenograft tumor assay. In addition, the mechanism of CASC9 function was determined using luciferase reporter assay. Western blot was used to analyze protein expressions in our paper.

RESULTS

LncRNA CASC9 was found to be up-regulated in OS. Knockdown of CASC9 inhibited the proliferation and invasion of OS cells. Besides, miR-874-3p was identified as the target of CASC9, and SOX12 acted as a potential target of miR-874-3p. The down-regulation of miR-874-3p recovered the reduction in cell invasion and proliferation in vitro which were induced by CASC9 knockdown and delayed the tumor progression in vivo.

CONCLUSION

LncRNA CASC9 promotes cell proliferation and invasion in OS via miR-874-3p/SOX12 axis. Our study might provide novel biomarkers and potential therapeutic targets for OS treatment.

Decoding signal transducer and activator of transcription 1 across various cancers through data mining and integrative analysis

OBJECTIVES

Using different online available databases and Bioinformatics tools, we extensively studied the role STAT1 across different cancers.

METHODS

STAT1 mRNA, protein expression, and promoter methylation were analyzed and validated using UALCAN, GENT2, Human Protein Atlas (HPA), and MEXPRESS. Furthermore, the potential prognostic values were evaluated through KM plotter. Then, cBioPortal was utilized to examine the STAT1-related genetic mutations, while pathway enrichment analysis was performed using DAVID. To identify STAT1 targeted microRNAs (miRNAs) and transcription factors (TFs) we used Enricher. Moreover, a correlational analysis between STAT1 expression tumor purity and CD8+ T immune cells and a gene-drug interaction network analysis was performed using TIMER, CTD, and Cytoscape.

RESULTS

In 23 major human cancers, STAT1 expression was notably up-regulated relative to corresponding controls. As well, the elevated expression of STAT1 was exclusively found to be associated with the reduced overall survival (OS) of Esophageal Carcinoma (ESCA), Kidney Renal Clear Cell Carcinoma (KIRC), and Lung adenocarcinoma (LUAD) patients. This implies that STAT1 plays a significant role in the development and progression of these three cancers. Further pathway analysis indicated that STAT1 enriched genes were involved in six critical pathways, while a few interesting correlations were also documented between STAT1 expression and promoter methylation level, tumor purity, CD8+ T immune cells infiltration, and genetic alteration. In addition, we have also predicted a few miRNAs, TFs, and chemotherapeutic drugs that could regulate the STAT1 expression.

CONCLUSION

The current study revealed the shared oncogenic, diagnostic, and prognostic role of STAT1 in ESCA, KIRC, and LUAD.

A Pleiotropic Role of Long Non-Coding RNAs in the Modulation of Wnt/β-Catenin and PI3K/Akt/mTOR Signaling Pathways in Esophageal Squamous Cell Carcinoma: Implication in Chemotherapeutic Drug Response

Despite the availability of modern techniques for the treatment of esophageal squamous cell carcinoma (ESCC), tumor recurrence and metastasis are significant challenges in clinical management. Thus, ESCC possesses a poor prognosis and low five-year overall survival rate. Notably, the origin and recurrence of the cancer phenotype are under the control of complex cancer-related signaling pathways. In this review, we provide comprehensive knowledge about long non-coding RNAs (lncRNAs) related to Wnt/β-catenin and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway in ESCC and its implications in hindering the efficacy of chemotherapeutic drugs. We observed that a pool of lncRNAs, such as HERES, TUG1, and UCA1, associated with ESCC, directly or indirectly targets various molecules of the Wnt/β-catenin pathway and facilitates the manifestation of multiple cancer phenotypes, including proliferation, metastasis, relapse, and resistance to anticancer treatment. Additionally, several lncRNAs, such as HCP5 and PTCSC1, modulate PI3K/Akt/mTOR pathways during the ESCC pathogenesis. Furthermore, a few lncRNAs, such as AFAP1-AS1 and LINC01014, block the efficiency of chemotherapeutic drugs, including cisplatin, 5-fluorouracil, paclitaxel, and gefitinib, used for ESCC treatment. Therefore, this review may help in designing a better therapeutic strategy for ESCC patients.

Long noncoding RNA VPS9D1-AS1 promotes esophageal squamous cell carcinoma progression via the Wnt/β-catenin signaling pathway

The VPS9D1 antisense RNA1 (VPS9D1-AS1, lncRNA MYU) can act as an oncogene or an antioncogene in different malignancies. In the present study, we demonstrated that VPS9D1-AS1 is significantly upregulated in esophageal squamous cell carcinoma (ESCC) and assessed its biological function and clinical prognosis. RNA-sequencing was conducted in four pairs of ESCC tissues and normal adjacent tissues (NATs). Compared with controls, lncRNA VPS9D1-AS1 was highly expressed in ESCC tissues, cell lines and plasma. VPS9D1-AS1 upregulation significantly correlated with the histopathological grade and clinical stage of ESCC. Analyses revealed poor prognosis in ESCC patients with high VPS9D1-AS1 expression. VPS9D1-AS1 knockdown led to the inhibition of tumor proliferation, migration, and invasion in vivo and vitro. VPS9D1-AS1 silencing downregulated the Wnt/β-catenin signaling pathways by acting on key proteins such as β-catenin and c-Myc. However, the expressions of these proteins increased after the addition of pathway agonist CT99021. Therefore, taken together VPS9D1-AS1 is highly expressed in ESCC and its expression can lead to poor prognosis. In conclusion, this study suggested that VPS9D1-AS1 acts as a vital part in facilitating ESCC progression and can be a potential biomarker for the diagnosis of patients with ESCC.

LncRNACASC9 promotes proliferation, metastasis, and cell cycle inovarian carcinoma cells through cyclinG1/TP53/MMP7 signaling

Ovarian cancer (OC) brings about serious physical and psychological burden for female patients. LncRNA CASC9 has been reported to be intimately linked with the occurrence and development of several tumors. However, the biological role of lncRNA CASC9 in OC still lacks sufficient evidence. The expressions of CASC9 and miR-488-3p in OC cell lines and xenograft mice were detected by qRT-PCR assay. Cell Counting Kit-8 (CCK-8) assay was used to assess cell inhibition rate and cell proliferation in OVCAR-3 and OVCAR-3/DDP cells. Wound healing assay and transwell assay were performed to evaluate the capacity of migration and invasion, respectively. In addition, cell apoptosis was measured by TUNEL assay and cell cycle was assessed by flow cytometric analysis. Moreover, western blotting was carried out to detect the cyclinG1 (CCNG1)/TP53/MMP7 signaling and apoptosis-related proteins. Furthermore, luciferase reporter assay was performed to verify the combination of CASC9 with CCNG1 and miR-488-3p. The results of our study revealed that CASC9 expression was upregulated while miR-488-3p and CCNG1 expression was downregulated in OC cells with significant higher TP53 and MMP7 protein levels compared with normal ovarian surface epithelial cells. Additionally, luciferase reporter assay confirmed CASC9 bond to miR-488-3p/CCNG1. CASC9 silencing inhibited cell proliferation, migration, and invasion whereas promoted cell inhibition rate and apoptosis in vitro and in vivo. However, CASC9 overexpression showed the opposite effects. In summary, LncRNA CASC9 played a regulative role in ovarian carcinoma by cyclinG1/TP53/MMP7 signaling via binding to miR-488-3p in vivo and in vitro.

Long non‑coding RNA SNHG3 promotes the development of non‑small cell lung cancer via the miR‑1343‑3p/NFIX pathway

The aim of the present study was to identify the function of long non‑coding RNA (lncRNA) small nucleolar RNA host gene 3 (SNHG3) and examine its effects on non‑small cell lung cancer (NSCLC). A series of in vitro experiments were employed to evaluate the effects of SNHG3 on the progression of NSCLC, including Cell Counting Kit‑8, 5‑Ethynyl‑2'‑deoxyuridine, flow cytometry, wound healing, Transwell, western blotting and reverse transcription‑quantitative PCR assays. Bioinformatics analyses and a luciferase reporter assay were performed to identify the target gene of SNHG3 and microRNA (miR)‑1343‑3p. Finally, recuse experiments were conducted to verify the effect of SNHG3 and its target gene on proliferation, apoptosis, migration and invasion. The findings indicated that lncRNA SNHG3 was highly expressed in NSCLC tissues and cell lines. Knockdown of lncRNA SNHG3 inhibited cell proliferation, migration and invasion, and accelerated cell apoptosis in NSCLC cell lines. The results of the bioinformatics analysis and the luciferase reporter assay indicated that lncRNA SNHG3 directly bound to miR‑1343‑3p and that it could downregulate the expression levels of miR‑1343‑3p to promote the progression of NSCLC. Rescue experiments indicated that lncRNA SNHG3 increased nuclear factor IX (NFIX) expression by sequestering miR‑1343‑3p in NSCLC. These results suggested that the SNHG3/miR‑1343‑3p/NFIX axis may serve as a novel prognostic biomarker and therapeutic target for NSCLC.

Oncogenic LncRNA CASC9 in Cancer Progression

BACKGROUND

Long non-coding RNAs (LncRNAs), with the length of over 200 nucleotides, that originate from intergenic, antisense, or promoter-proximal regions, are a large family of RNAs that lack coding capacity. Emerging evidences illustrated that LncRNAs played significant roles in a variety of cellular functions and biological processes in profuse human diseases, especially in cancers. Cancer susceptibility candidate 9 (CASC9), as a member of the LncRNAs group, firstly found its oncogenic function in esophageal cancer. In the following recent studies, a growing amount of human malignancies are verified to be correlated with CASC9, most of which are derived from the squamous epithelium tissue. This present review attempts to highlight the latest insights into the expression, functional roles, and molecular mechanisms of CASC9 in different human malignancies.

METHODS

In this review, the latest findings related to the pathophysiological processes of CASC9 in human cancers were summarized and analyzed, and the associated studies collected in systematic retrieval of PubMed used lncRNA and CASA9 as keywords.

RESULTS

CASC9 expression is identified to be aberrantly elevated in a variety of malignancies. The over-expression of CASC9 has been suggested to accelerate cell proliferation, migration, cell growth and drug resistance of cancer cells, while depressing cell apoptosis, revealing its role as an oncogene. Moreover, the current review demonstrated CASC9 as closely related to the neoplastic transformation of squamous epithelial cells and squamous metaplasia in non-squamous epithelial tissues. Finally, we discuss the limitations and tremendous diagnostic/ therapeutic potential of CASC9 in various human cancers.

CONCLUSION

Long non-coding RNA CASC9 likely serve as useful disease biomarkers or therapeutic targets which be effectively applied in the treatment of different kinds of cancers.

Long non-coding RNA CASC9 promotes the progression and development of gastric cancer via regulating miR-370/EGFR axis

lncRNA cancer susceptibility 9 (CASC9) is a pivotal modulator in various cancers, such as colorectal cancer, breast cancer and esophageal cancer. However, its exact role in gastric cancer (GC) has not been systematically studied. Here, using a combination of molecular and cell biology approaches, we found that CASC9 also acts as a factor promoting the progression of GC. First, mRNA and protein expression levels were quantified by real-time quantitative reverse transcription PCR (qRT-PCR) and western blot, respectively. Second, CCK-8 assay, colony formation assay and cell cycle analysis were performed to compare the cell growth abilities when CASC9 was knocked down. Third, the proliferative cells were determined by labeling Edu and the regulatory effect of CASC9 on miR-370 was detected by RNA-protein pull-down and luciferase reporter assays. Finally, in vivo mice model was established to verify the role of CASC9 in promoting GC progression. Our results showed that CASC9 was up-regulated significantly in both GC tissues and cell lines. Conversely, CASC9 knockdown inhibited GC growth in vitro. Further analysis indicated that CASC9 directly targeted miR-370 and negatively regulated miR-370 expression in GC. Besides, EGFR (epidermal growth factor receptor) was identified as a direct target gene of miR-370. Taken together our results support a model in which CASC9 promotes GC progression through miR-370/EGFR/ERK/AKT pathway. Finally, in vivo CASC9 knockdown resulted in impaired GC growth. In sum, this study firstly demonstrates that lncRNA CASC9 acts as an oncogene through altering EGFR expression level via negatively regulating miR-370 expression.

Long non-coding RNA LINC00488 facilitates thyroid cancer cell progression through miR-376a-3p/PON2

Objective: Long non-coding RNAs (lncRNAs) recently have been identified as influential indicators in a variety of malignancies. The aim of the present study was to identify a functional lncRNA LINC00488 and its effects on thyroid cancer in the view of cell proliferation and apoptosis.

Methods: In order to evaluate the effects of LINC00488 on the cellular process of thyroid cancer, we performed a series of in vitro experiments, including cell counting kit-8 (CCK-8) assay, EdU (5-ethynyl-2′-deoxyuridine) assay, flow cytometry, transwell chamber assay, Western blot and RT-qPCR. The target gene of LINC00488 was then identified by bioinformatics analysis (DIANA and TargetScan). Finally, a series of rescue experiments was conducted to validate the effect of LINC00488 and its target genes on proliferation, migration, invasion and apoptosis of thyroid cancer.

Results: Our findings revealed that LINC00488 was highly expressed in thyroid cancer cell lines (BCPAP, BHP5-16, TPC-1 and CGTH-W3) and promoted the proliferation, migration and invasion, while inhibited the apoptosis of thyroid cancer cells (BCPAP and TPC-1). The results of bioinformatics analysis and dual luciferase reporter gene assay showed that LINC00488 could directly bind to miR-376a-3p and down-regulated the expression level of miR-376a-3p. In addition, Paraoxonase-2 (PON2) was a target gene of miR-376a-3p and negatively regulated by miR-376a-3p. Rescue experiment indicated that LINC00488 might enhance PON2 expression by sponging miR-376a-3p in thyroid cancer.

Conclusion: Taken together, our study revealed that lncRNA LINC00488 acted as an oncogenic gene in the progression of thyroid cancer via regulating miR-376a-3p/PON2 axis, which indicated that LINC00488-miR-376a-3p-PON2 axis could serve as novel biomarkers or potential targets for the treatment of thyroid cancer.

Involvement of long non-coding RNAs in the progression of esophageal cancer

Esophageal cancer (EC) is one of the most common malignant tumors of the digestive system with high incidence and mortality rate worldwide. Therefore, exploring the pathogenesis of EC and searching for new targeted therapies are the current research hotspot for EC treatment. Long non‐coding RNAs (lncRNAs) are endogenous RNAs with more than 200 nucleotides, but without protein‐coding function. In recent years, lncRNAs have gradually become the focuses in the field of non‐coding RNA. Some lncRNAs have been proved to be closely related to the pathogenesis of EC. Many lncRNAs are abnormally expressed in EC and participate in many biological processes including cell proliferation, apoptosis, and metastasis by inhibiting or promoting target gene expression. LncRNAs can also regulate the progression of EC through epithelial‐mesenchymal transformation (EMT), which is closely related to the occurrence, development, and prognosis of EC. In this article, we review and discuss the involvement of lncRNAs in the progression of EC.

Long Noncoding RNAs in Gastrointestinal Cancer: Tumor Suppression Versus Tumor Promotion

Approximately 80% of the human genome harbors biochemical marks of active transcription that its majority transcribes to noncoding RNAs, namely long noncoding RNAs (lncRNAs). LncRNAs are heterogeneous RNA transcripts that regulate critical biological processes such as cell survival and death. They involve in the progression of different cancers by affecting transcriptional and post-transcriptional modifications as well as epigenetic control of numerous tumor suppressors and oncogenes. Recent findings show that aberrant expression of lncRNAs is associated with tumor initiation, progression, invasion, and overall survival of patients with gastrointestinal (GI) cancers. Some lncRNAs play as tumor suppressors in all GI cancers, but others play as tumor promoters. However, some other lncRNAs might function as a tumor suppressor in one GI cancer, but as a tumor promoter in another GI cancer type. This fact highlights possible context dependency of the expression patterns and roles of at least some lncRNAs in GI cancer development and progression. Here, we review the functional relation of lncRNAs involved in the development and progression of GI cancer by focusing on their roles as tumor suppressor and tumor promoter genes.

Exploring the Effect of Differentially Expressed Long Non-coding RNAs Driven by Copy Number Variation on Competing Endogenous RNA Network by Mining Lung Adenocarcinoma Data

Lung cancer is the first cause of cancer death, and gene copy number variation (CNV) is a vital cause of lung cancer progression. Prognosis prediction of patients followed by medication guidance by detecting CNV of lung cancer is emerging as a promising precise treatment in the future. In this paper, the differences in CNV and gene expression between cancer tissue and normal tissue of lung adenocarcinoma (LUAD) from The Cancer Genome Atlas Lung Adenocarcinoma data set were firstly analyzed, and greater differences were observed. Furthermore, CNV-driven differentially expressed long non-coding RNAs (lncRNAs) were screened out, and then, a competing endogenous RNA (ceRNA) regulatory network related to the gene CNV was established, which involved 9 lncRNAs, seven microRNAs, and 178 downstream messenger RNAs (mRNAs). Pathway enrichment analyses sequentially performed revealed that the downstream mRNAs were mainly enriched in biological pathways related to cell division, DNA repair, and so on, indicating that these mRNAs mainly affected the replication and growth of tumor cells. Besides, the relationship between lncRNAs and drug effects was explored based on previous studies, and it was found that LINC00511 and LINC00942 in the CNV-associated ceRNA network could be used to determine tumor response to drug treatment. As examined, the drugs affected by these two lncRNAs mainly targeted metabolism, target of rapamycin signaling pathway, phosphatidylinositol-3-kinase signaling pathway, epidermal growth factor receptor signaling pathway, and cell cycle. In summary, the present research was devoted to analyzing CNV, lncRNA, mRNA, and microRNA of lung cancer, and nine lncRNAs that could affect the CNV-associated ceRNA network we constructed were identified, two of which are promising in determining tumor response to drug treatment.

LncRNA TUG1 promotes esophageal cancer development through regulating PLK1 expression by sponging miR-1294

OBJECTIVES

Esophageal cancer is one of the malignant tumor with poor survival. The 5-year survival rate of esophageal cancer patients remains poor due to limited therapeutic options and the development of drug-resistance. Recent evidence suggests that long non-coding RNAs (lncRNAs) are involved in occurrence and development of tumor, however, the molecular mechanisms of lncRNA taurine-upregulated gene 1 (TUG1) in esophageal cancer remain unknown.

RESULTS

TUG1 was overexpressed in esophageal cancer tissues and cells. The knockdown of TUG1 repressed proliferation and invasion, while promoted apoptosis of esophageal cancer cells by negatively regulating miR-1294 expression. Furthermore, PLK1 was a target mRNA of miR-1294 in esophageal cancer cells. Therefore, the effects of PLK1 silencing on proliferation, apoptosis, and invasion of esophageal cancer cells could be overturned by silencing miR-1294. Additionally, TUG1 silencing inhibited growth of tumor cells in vivo.

CONCLUSIONS

TUG1 was found as oncogenic gene in esophageal cancer. Mechanically, TUG1 attributed to esophageal cancer process by regulating miR-1294/ PLK1 axis.

Silencing of long non-coding RNA LINC01270 inhibits esophageal cancer progression and enhances chemosensitivity to 5-fluorouracil by mediating GSTP1methylation

Esophageal cancer (EC) is a serious digestive malignancy which remains the sixth leading cause of cancer-related deaths worldwide. Emerging evidence suggests the involvement of long non-coding RNAs (lncRNAs) in the tumorigenesis of EC and thus, in this study we explored the potential effects of lncRNA LINC01270 on EC cell proliferation, migration, invasion and, drug resistance via regulation of glutathione S-transferase P1 (GSTP1) methylation. First, we screened out the EC-related differentially expressed lncRNAs, and the expression of our top candidate LINC01270 was quantified in EC tissues and cells. To define the role of LINC01270 in EC progression, we evaluated the proliferation, migration and invasion of EC cells when the LINC01270 was overexpressed or knocked down, in the presence of the GSTP1 methylation inhibitor SGI-1027 and 5-fluorouracil (5-FU). In addition, interaction between LINC01270 and methylation of the GSTP1 promoter was identified. Finally, we assessed transplantable tumor growth in nude mice. LINC01270 was up-regulated and GSTP1 was down-regulated in EC tissues and cells. Silencing of LINC01270 inhibited migration and invasion, and enhanced the sensitivity of 5-FU in EC cells. We found that LINC01270 recruited the DNA methyltransferases DNMT1, DNMT3A and DNMT3B initiating GSTP1 promoter methylation, thereby leading to the proliferation, migration, invasion and drug resistance of EC cells. Moreover, GSTP1 overexpression was observed to reverse the effects of LINC01270 overexpression on EC cells and their response to 5-FU. Taken together, this study shows that inhibition of LINC01270 can lead to suppression of EC progression via demethylation of GSTP1, highlighting this lncRNA as a potential target for EC treatment.

Silencing long non-coding RNA CASC9 inhibits colorectal cancer cell proliferation by acting as a competing endogenous RNA of miR-576-5p to regulate AKT3

Increasing studies have shown that long non-coding RNAs (lncRNAs) are regarded as important regulators in the occurrence and development of colorectal cancer (CRC). Although lncRNA CASC9 has been studied in CRC, the detailed regulatory mechanism of CASC9 in CRC is still unclear. In this study, we found that CASC9 was significantly upregulated in CRC tissues and cell lines compared to normal controls and that aberrant expression was associated with the tumor-node-metastasis (TNM) stage of CRC. Functionally, CASC9 depletion efficiently inhibited the proliferation of CRC cells and induced cell apoptosis in vitro. Mechanistically, CASC9 was mainly enriched in the cytoplasm of CRC cells and interacted directly with miR-576-5p. Downregulation of miR-576-5p reversed the inhibitory effect of CASC9 siRNA on CRC cell progression. Furthermore, AKT3 has been identified as a downstream target of miR-576-5p. Spearman’s correlation analysis revealed that AKT3 was negatively correlated with miR-576-5p but positively correlated with CASC9. Downregulation of miR-576-5p restored the effect of CASC9 silencing on AKT3 expression. Therefore, silencing CASC9 could downregulate the expression of AKT3 by reducing the competitive binding of CASC9 to miR-576-5p, thus suppressing CRC cell proliferation and promoting cell apoptosis. In summary, we identified CASC9 as an oncogenic lncRNA in CRC and defined the CASC9/miR-576-5p/AKT3 axis, which might be considered a potential therapeutic target for CRC patients, as a novel molecular mechanism implicated in the proliferation and apoptosis of CRC.

Clinicopathological association and prognostic value of long non-coding RNA CASC9 in patients with cancer: A meta-analysis

Several studies have reported a prognostic role of the long non-coding RNA (lncRNA) cancer susceptibility candidate 9 (CASC9) in various cancer types, but its clinical significance has remained inconclusive. The aim of the present meta-analysis was to evaluate the impact of CASC9 expression on the prognosis and clinicopathological features of patients with cancer patients. The PubMed, Embase, Cochrane Library and Web of Science databases were searched for relevant literature and eight studies, including 565 patients with cancer, were selected. The quality of these studies was appraised with the Newcastle-Ottawa Scale (NOS) and the association between CASC9 expression and prognosis or clinicopathological features was analyzed. Patients with high expression levels of CASC9 in their tumor tissues had a lower overall survival rate compared with those in the low CASC9 expression group (hazard ratio=2.25, 95% CI: 1.60-3.17, P<0.001). Furthermore, elevated CASC9 expression was significantly associated with deeper tumor invasion [odds ratio (OR)=2.66, 95% CI: 1.72-4.14, P<0.001], poor tumor differentiation (OR=2.44, 95% CI: 1.24-4.78, P=0.009), lymph node metastasis (OR=3.42, 95% CI: 1.98-5.92, P<0.001) and advanced clinical stage (OR=3.21, 95% CI: 2.21-4.66, P<0.001). In conclusion, CASC9 is a promising biomarker for predicting the prognosis of cancer patients and should be validated in the clinic.

Small nucleolar RNA host gene 22 (SNHG22) promotes the progression of esophageal squamous cell carcinoma by miR-429/SESN3 axis

Background

It has been observed that lncRNAs have been taking part in many cancer progressions, including non-small cell lung cancer and gastric cancer. Meanwhile, lncRNA small nucleolar RNA host gene 22 (SNHG22) has been studied, taking part in the progression of ovarian epithelial carcinoma. However, we know little about the function of SNHG22 in esophageal squamous cell carcinoma (ESCC).

Methods

In this study, we will explore the inner mechanism of SNHG22 in ESCC. Quantitative real-time PCR (qRT-PCR) assay was implemented in ESCC cells for detecting the expression of lncRNA, SNHG22, and miR-429. Also, functional experiments, including CCK8 and colony formation assay, were implemented to assess the growth of ESCC cells. Meanwhile, flow cytometry analysis was conducted to test the apoptosis of ESCC cells. The immunofluorescence (IF) assay and western blot were conducted to verify the autophagy of ESCC cells.

Results

Inhibition of SNHG22 was found that can inhibit the progression and promotes autophagy and apoptosis of ESCC cells. Meanwhile, as subcellular fraction assay and FISH assay found that SNHG22 mainly in the cytoplasm, miR-429 was found can bind to SNHG22 and SESN3 by RIP assay and luciferase reporter assay. SESN3 was found it can play the oncogene in ESCC cells.

Conclusions

SNHG22 promotes the progression of ESCC by the miR-429/SESN3 axis.

STAT3-Induced Upregulation of lncRNA CASC9 Promotes the Progression of Bladder Cancer by Interacting with EZH2 and Affecting the Expression of PTEN

Objective

Long non-coding RNA (lncRNA) cancer susceptibility candidate 9 (CASC9) has been reported to play a vital role in tumorigenesis. This study explored the biological role of CASC9 and its regulation mechanism in bladder cancer (BC).

Methods

Gene expression was evaluated using quantitative reverse transcription polymerase chain reaction and Western blot. The functional role of CASC9 in BC was studied using Cell Counting Kit-8, colony formation assay, scratch wound healing assay, transwell invasion assay, and xenograft tumor assay. In addition, the mechanism of CASC9 function in BC was determined using RNA immunoprecipitation assay and chromatin immunoprecipitation assay.

Results

CASC9 was upregulated in BC tissues and cell lines, and correlated with the staging and metastasis in BC. Knockdown of CASC9 inhibited the proliferation, migration, and invasion of BC cells. Similarly, silencing of CASC9 inhibited tumor growth in vivo. Signal transducer and activator of transcription 3 (STAT3) was upregulated in BC tissues and cell lines, and positively correlated with CASC9 in BC tissues. Moreover, CASC9 was shown to be regulated by STAT3 in BC cells. Furthermore, CASC9 regulated phosphatase and tensin homolog (PTEN) expression by interacting with enhancer of zeste homolog 2 (EZH2). More significantly, CASC9 silencing-mediated inhibition of BC progression was partly reversed by EZH2 overexpression or PTEN inhibition.

Conclusion

Upregulation of CASC9 induced by STAT3 promoted the progression of BC by interacting with EZH2 and affecting the expression of PTEN, representing a novel regulatory mechanism for BC progression.

Long non-coding RNA ESCCAL-1 promotes esophageal squamous cell carcinoma by down regulating the negative regulator of APOBEC3G

The expression of lncRNA ESCCAL-1 is upregulated in esophageal squamous cell carcinoma (ESCC). However, the molecular pathways regulated by ESCCAL-1 in esophageal cancer remain obscure. We found that high expression of the lncRNA ESCCAL-1 in human ESCC tumors correlated with worse clinicopathologic features. Furthermore, depletion of ESCCAL-1 in ESCC models inhibited the cellular processes associated with malignancy, including proliferation, migration and invasion, resistance to apoptosis, and impaired tumor growth in mice. Using a combinatorial approach, we discovered that ESCCAL-1 regulates malignant phenotypes in ESCC by acting as a molecular sponge for miR-590-3p. This interaction prevents miR-590-3p from suppressing APOBEC3G expression. Increased APOBEC3G was also a biomarker of worse clinicopathologic features in human ESCC tumors. Depletion of ESSCAL-1 or APOBEC3G, or overexpression of miR-590-3p resulted in increased apoptosis due to downregulation of the PI3K/Akt signaling. This study demonstrates that the lncRNA ESCCAL-1 promotes malignant features of ESCC by relieving the inhibitory effect of miR-590-3p on APOBEC3G expression and identifies potential biomarkers or therapeutic targets to improve ESCC treatment outcomes.

Long non-coding RNA CASC9 promotes the progression of retinoblastoma via interacting with miR-145-5p

Abnormal expression of long non-coding RNA cancer susceptibility candidate 9 (CASC9) has been found to play vital roles in many human tumors. However, the role and the regulatory mechanism of CASC9 have not yet been demonstrated in retinoblastoma (RB). Hence, we performed this study to explore the function and mechanism of CASC9 in RB. CASC9 expression was firstly detected in human RB tissues and cells. The influence of CASC9 on the malignant phenotypes of RB cells, including cell proliferation, invasion, epithelial-mesenchymal transition (EMT) and apoptosis, was analyzed by overexpressing or silencing CASC9. The association between CASC9, miR-145-5p and E2F transcription factor 3 (E2F3) was determined by dual-luciferase reporter assay and RNA immunoprecipitation. We found that CASC9 expression was elevated in RB tissues and cells. Overexpression of CASC9 significantly facilitated the proliferation, invasion and EMT of RB cells. On the contrary, knockdown of CASC9 inhibited the proliferation, invasion and EMT, while enhanced the apoptosis of RB cells. CASC9 acted as a competing endogenous RNA (ceRNA) for miR-145-5p to regulate E2F3. Additionally, miR-145-5p inhibitor and E2F3 overexpression both partly reversed the malignant phenotypes of RB cells affected by CASC9 knockdown. However, miR-145-5p overexpression further strengthened these features induced by CASC9 downregulation. These findings suggested that CASC9 contributed to RB development by regulating E2F3 via sponging miR-145-5p. CASC9 might be a possible therapeutic target for RB.

Multi-faceted epigenetic dysregulation of gene expression promotes esophageal squamous cell carcinoma

Epigenetic landscapes can shape physiologic and disease phenotypes. We used integrative, high resolution multi-omics methods to delineate the methylome landscape and characterize the oncogenic drivers of esophageal squamous cell carcinoma (ESCC). We found 98% of CpGs are hypomethylated across the ESCC genome. Hypo-methylated regions are enriched in areas with heterochromatin binding markers (H3K9me3, H3K27me3), while hyper-methylated regions are enriched in polycomb repressive complex (EZH2/SUZ12) recognizing regions. Altered methylation in promoters, enhancers, and gene bodies, as well as in polycomb repressive complex occupancy and CTCF binding sites are associated with cancer-specific gene dysregulation. Epigenetic-mediated activation of non-canonical WNT/β-catenin/MMP signaling and a YY1/lncRNA ESCCAL-1/ribosomal protein network are uncovered and validated as potential novel ESCC driver alterations. This study advances our understanding of how epigenetic landscapes shape cancer pathogenesis and provides a resource for biomarker and target discovery.

Long non-coding RNA CASC9 promotes tumor growth and metastasis via modulating FZD6/Wnt/β-catenin signaling pathway in bladder cancer

BACKGROUND

Accumulating evidence have highlighted the importance of long noncoding RNAs (lncRNAs) in multiple cancers development and progression. Cancer susceptibility candidate 9 (CASC9) is a novel long non-coding RNA and plays important regulatory role in diverse biological processes of cancers. However, the clinical significance and molecular mechanism of CASC9 in bladder cancer is still unknown.

METHODS

Comprehensive lncRNAs profiling analysis were conducted to identify lncRNAs profile alterations and uncover valuable lncRNA candidates for bladder cancer. The expression level of CASC9 was determined in a total of 106 patients with bladder cancer. Loss-of-function experiments were performed to identify the functions of CASC9 in tumor growth and metastasis of bladder cancer in vitro and in vivo. Bioinformatics analysis and further experiments were performed to explore the molecular mechanisms underlying the functions of CASC9.

RESULTS

This study found that CASC9 expression was markedly upregulated in bladder cancer and related to histological grade, TNM stage and prognosis. Knockdown of CASC9 inhibited tumor growth and metastasis of bladder cancer in vitro and in vivo. Mechanistically, we found that CASC9 functions as a miRNA sponge to positively regulate FZD6 expression and subsequently activates Wnt/β-catenin signaling pathway, thus playing an oncogenic role in bladder cancer pathogenesis.

CONCLUSION

In summary, lncRNA CASC9 plays a critical regulatory role in bladder cancer. The CASC9/miR-497-5p/ FZD6 axis provides insights for regulatory mechanism of bladder cancer, and new strategies for clinical practice.

LncRNA HOTAIR-mediated MTHFR methylation inhibits 5-fluorouracil sensitivity in esophageal cancer cells

BACKGROUND

Esophageal cancer (EC) represents one of the most aggressive digestive neoplasms globally, with marked geographical variations in morbidity and mortality. Chemoprevention is a promising approach for cancer therapy, while acquired chemoresistance is a major obstacle impeding the success of 5-fluorouracil (5-FU)-based chemotherapy in EC, with the mechanisms underlying resistance not well-understood. In the present study, we focus on exploring the role of long non-coding RNA (lncRNA) HOTAIR in EC progression and sensitivity of EC cells to 5-FU.

METHODS

Paired cancerous and pre-cancerous tissues surgically resected from EC patients were collected in this study. Promoter methylation of the MTHFR was assessed by methylation-specific PCR. RIP and ChIP assays were adopted to examine the interaction of DNA methyltransferases (DNMTs) with lncRNA HOTAIR and MTHFR, respectively. EC cells resistant to 5-FU were induced by step-wise continuous increasing concentrations of 5-FU. The sensitivity of EC cells to 5-FU in vivo was evaluated in nude mice treated with xenografts of EC cells followed by injection with 5-FU (i.p.).

RESULTS

We found reciprocal expression patterns of lncRNA HOTAIR and MTHFR in EC tissues and human EC cells. Interference with lncRNA HOTAIR enhanced 5-FU-induced apoptosis, exhibited anti-proliferative activity, and reduced promoter methylation of the MTHFR in EC cells. Besides, overexpression of MTHFR attenuated the acquired chemoresistance induced by overexpression of lncRNA HOTAIR in EC cells. At last, enhanced chemosensitivity was observed in vivo once nude mice xenografted with lncRNA HOTAIR-depleted EC cells.

CONCLUSION

Together, our study proposes that pharmacologic targeting of lncRNA HOTAIR sensitizes EC cells to 5-FU-based chemotherapy by attenuating the promoter hypermethylation of the MTHFR in EC.

CASC9 Facilitates Cell Proliferation in Bladder Cancer by Regulating CBX2 Expression

BACKGROUND

As the seventh most common urologic carcinoma worldwide, approximately 430,000 patients are diagnosed with bladder cancer (BC) every year. Increasing evidence indicates that long noncoding RNAs (lncRNAs) play crucial roles in the progression of BC.

OBJECTIVES

This study is aimed to explore the function and mechanism of CASC9 in BC.

METHODS

Bioinformatics analysis and experiments including RT-qPCR, luciferase reporter, Cell Counting Kit-8 assay, Western blot, RNA immunoprecipitation assay, and TUNEL staining were applied to explore the function and mechanism of CASC9 in BC tissues and cell lines.

RESULTS

Our study demonstrated that CASC9 was upregulated in BC tissues and cell lines. Moreover, we found that CASC9 knockdown notably decreased proliferation while increased apoptotic rate in BC cells. Mechanistically, bioinformatics prediction and following experiments indicated that CASC9 worked as a competing endogenous RNA (ceRNA) of CBX2 through sponging miR-497-5p. Meanwhile, we recognized that CASC9 and miR-497-5p negatively regulated each other in a mutual way. Furthermore, we found that miR-497-5p shared binding site with CBX2. In addition, miR-497-5p could negatively regulated CBX2, while CASC9 could positively regulated CBX2. Rescue assays reveled that CBX2 overexpression could reversed the reduction of cell proliferation or the enhancement of cell apoptosis induced by CASC9 suppression.

CONCLUSIONS

Our study manifests the first evidence that CASC9 serves as an oncogene in BC and accelerates cell proliferation by modulating miR-497-5p/CBX2 axis. The present study may provide a cogitable target for BC therapy.

Cancer Susceptibility Candidate 9 (CASC9): A Novel Targetable Long Noncoding RNA in Cancer Treatment

Based on epidemiological data provided by the World Health Organization (2018), cancer is the second most prevalent cause of death worldwide. Several factors are thought to contribute to the high mortality rate in cancer patients, including less-than-optimal diagnostic and therapeutic strategies. Thus, there is an urgent need to identify accurate biomarkers with diagnostic, prognostic, and potential therapeutic applications. In this regard, long noncoding RNAs (lncRNAs) hold immense potential due to their regulatory roles in cancer development and associated cancer hallmarks. Recently, CASC9 transcripts have attracted significant attention due to their altered expression during the pathogenesis of cancer and their apparent contributions to various cancer-associated phenotypes involving a broad spectrum of molecular mechanisms. Here, we have provided an in-depth review describing the known functions of the lncRNA CASC9 in cancer development and progression.

LINC01980 facilitates esophageal squamous cell carcinoma progression via regulation of miR-190a-5p/MYO5A pathway

Understanding the role of Long non-coding RNAs (lncRNAs) in tumorigenesis in diverse human malignancies would helpful for targeted therapies, containing esophageal squamous cell carcinoma (ESCC). However, the specific role and molecular mechanisms of LINC01980 in ESCC remain unclarified. In this study, we investigated the expression level, function role, and molecular mechanisms of LINC01980 in esophageal cancer cells and ESCC tissues. The high expression of LINC01980 was detected in ESCC tissues and cells, and predicted poor prognosis. LINC01980 promoted the cell proliferation, migration, invasion ability and epithelial-mesenchymal transition (EMT) progress in ESCC cells. In addition, a negative correlation between LINC01980 and miR-190a-5p or miR-190a-5p and MYO5A was observed in ESCC. We found that miR-190a-5p could directly bind with the mRNA of LINC01980 and MYO5A, and it was detected low expression in ESCC. We further demonstrated that the downregulation of MYO5A caused by overexpressing miR-190a-5p was released via upregulation of LINC01980. Functionally, LINC01980 acted as a competitively endogenous RNA (ceRNA) to impact the expression of MYO5A by sponging miR-190a-5p in ESCC. Therefore, these findings suggest that LINC01980 may act as an oncogenic lncRNA in ESCC and LINC01980/miR-190a-5p/MYO5A pathway contributes to the development of ESCC.

Long noncoding RNA LINC01234 silencing exerts an anti-oncogenic effect in esophageal cancer cells through microRNA-193a-5p-mediated CCNE1 downregulation

BACKGROUND

Long non-coding RNAs (lncRNAs) are transcribed pervasively in the genome and act to regulate chromatin remodeling and gene expression. Dysregulated lncRNA expression has been reported in many cancers, but the role of lncRNAs in esophageal cancer (EC) has so far remained poorly understood. In this study, we aimed to understand the effect of lncRNA LINC01234 on EC development through competitively binding to microRNA-193a-5p (miR-193a-5p).

METHODS

The Gene Expression Omnibus (GEO) database was used for microarray-based EC expression profiling. Gain- and loss-of-function analyses were carried out in human EC-derived Eca-109 and EC9706 cells. Expression analyses of miR-193a-5p, LINC01234, CCNE1, caspase-3, p21, Bax, cyclinD1 and Bcl-2 were performed using RT-qPCR and Western blotting. Cell proliferation, colony formation and apoptosis analyses were carried out using MTT, Hoechst 33258 and flow cytometry assays. A xenograft EC model in nude mice was used to evaluate in vivo tumor growth and CCNE1 expression.

RESULTS

Microarray-based analyses revealed that LINC01234 expression was increased in primary EC samples, whereas that of miR-193a-5p was decreased. We found that CCNE1 was a target of miR-193a-5p and that LINC01234, in turn, sponges miR-193a-5p. After treatment with si-LINC01234 or miR-193a-5p mimic, EC cells (Eca-109 and EC9706) exhibited cyclinD1 and Bcl-2 downregulation, and caspase-3, p21, Bax and cleaved caspase-3 upregulation. LINC01234 silencing or miR-193a-5p upregulation resulted in decreased proliferation and colony formation, and increased apoptosis of EC cells. In addition, LINC01234 silencing or miR-193a-5p upregulation resulted in reduced in vivo EC tumor growth and CCNE1 expression in nude mice.

CONCLUSIONS

We found that silencing of LINC01234 suppresses EC development by inhibiting CCNE1 through competitively binding to miR-193a-5p, which suggests that LINC01234 may represent a novel target for EC therapy.

A comprehensive analysis of coding and non-coding transcriptomic changes in cutaneous squamous cell carcinoma

Cutaneous Squamous Cell Carcinoma (cSCC) is the most common and fastest-increasing cancer with metastatic potential. Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) are novel regulators of gene expression. To identify mRNAs, lncRNAs and circRNAs, which can be involved in cSCC, RNA-seq was performed on nine cSCCs and seven healthy skin samples. Representative transcripts were validated by NanoString nCounter assays using an extended cohort, which also included samples from pre-cancerous skin lesions (actinic keratosis). 5,352 protein-coding genes, 908 lncRNAs and 55 circular RNAs were identified to be differentially expressed in cSCC. Targets of 519 transcription factors were enriched among differentially expressed genes, 105 of which displayed altered level in cSCCs, including fundamental regulators of skin development (MYC, RELA, ETS1, TP63). Pathways related to cell cycle, apoptosis, inflammation and epidermal differentiation were enriched. In addition to known oncogenic lncRNAs (PVT1, LUCAT1, CASC9), a set of skin-specific lncRNAs were were identified to be dysregulated. A global downregulation of circRNAs was observed in cSCC, and novel skin-enriched circRNAs, circ_IFFO2 and circ_POF1B, were identified and validated. In conclusion, a reference set of coding and non-coding transcripts were identified in cSCC, which may become potential therapeutic targets or biomarkers.

Biological and clinical relevance of metastasis-associated long noncoding RNAs in esophageal squamous cell carcinoma: A systematic review

Esophageal squamous cell carcinoma (ESCC) is a foremost cancer-related death worldwide owing to rapid metastasis and poor prognosis. Metastasis, as the most important reason for death, is biologically a multifaceted process involving a range of cell signaling pathways. Long noncoding RNAs (lncRNAs), as transcriptional regulators, can regulate numerous genomic processes and cellular processes such as cell proliferation, migration, and invasion. LncRNAs have also been shown to involve in/regulate the cancer metastasis-related signaling pathways. Hence, they have increasingly been brought to international attention in molecular oncology research. A number of researchers have attempted to reveal the biological and clinical relevance of lncRNAs in ESCC tumourigenesis and metastasis. The aberrant expression of these molecules in ESCC has regularly been reported to involve in various cellular processes and clinical features, including diagnosis, prognosis, and therapeutic responses. Here, we especially consider the pathways in which lncRNAs act as metastasis-mediated effectors, mainly by interacting with epithelial-mesenchymal transition-associated factors. We review the biological roles of lncRNAs through involving in ESCC metastasis as well as the clinical significance of the metastasis-related lncRNAs in cancer diagnosis and prognosis.

LncRNA CASC9 Affects Cell Proliferation, Migration, and Invasion of Tongue Squamous cell Carcinoma via Regulating miR-423-5p/SOX12 Axes

Introduction

The incidence of tongue squamous cell carcinoma (TSCC) has increased in recent decades. However, the function of long non-coding RNA (lncRNA) CASC9 in the occurrence and progression of TSCC is unclear. In this work, we attempted to clarify the role of lncRNA CASC9 in determining the phenotype of TSCC cells, and to clarify the underlying mechanisms.

Methods

We used qRT-PCR analysis to identify the level of CASC9 mRNA expression in TSCC clinical samples and cell lines. We investigated cell proliferation, and cell migration and invasion of TSCC cells transfected with siCASC9 or siNC using CCK-8 and transwell assays. Bioinformatics analysis and a luciferase reporter assay were employed to predict and verify the target microRNA (miRNA).

Results

CASC9 was up-regulated in the TSCC tissues and cells, and predicted a poor prognosis. CASC9 silencing significantly inhibited cell proliferation, migration, and invasion of the TSCC cells compared with the non-targeting control small interfering RNA (siCtrl) treatment. miR-423-5p was predicted as the targeting miRNA of CASC9; this was verified by a luciferase reporter assay. CASC9 expression showed a negative correlation with miR-423-5p expression and a positive correlation with SOX12 expression. The miR-423-5p inhibitor can rescue the carcinogenesis effect of CASC9 on TSCC cells.

Conclusion

Our work indicates that CASC9 plays a role in TSCC tumorigenesis; this novel information will improve TSCC molecular targeting therapy.

Long noncoding RNA CASC9 promotes the proliferation and metastasis of papillary thyroid cancer via sponging miR-488-3p

Cancer susceptibility candidate 9 (CASC9) is a recently identified lncRNA that acted as a tumor promotor in diversified cancer types. However, its role in papillary thyroid cancer (PTC) remains unknown. The expression of CASC9 was measured in 52 human PTC tissues and PTC cell lines as well as their controls. The proliferation, migration, and invasion of PTC cells were determined after knockdown or overexpression of CASC9 to evaluate the effect of CASC9 on PTC cells. Also, the role of PTC tumorigenesis was confirmed in mice xenograft models. Additionally, the underlying mechanisms of CASC9 were further researched. We found that CASC9 expression was augmented in human PTC tissues and cells. Higher CASC9 expression was associated with large tumor size, advanced stage, or lymph node metastasis. Downregulation of CASC9 significantly attenuated the proliferative, migrative, and invasive abilities of PTC cells, and suppressed tumorigenesis in vivo. While overexpression of CASC9 elevated the proliferation, migration, and invasion of PTC cells. miR‐488‐3p expression was decreased, and ADAM9 level was increased in PTC tissues and cells. CASC9 expression was negatively related to miR‐488‐3p, but positively associated with ADAM9 expression in PTC tissues. Molecular mechanism analysis revealed that CASC9 functioned via sponging miR‐488‐3p to regulate ADAM9 expression, followed by activation of EGFR‐Akt signaling. In conclusion, lncRNA CASC9 promoted the malignant phenotypes of PTC via modulating miR‐488‐3p/ADAM9 pathway. This study may provide a novel therapeutic target for the treatment of PTC.

The exploration of disease-specific gene regulatory networks in esophageal carcinoma and stomach adenocarcinoma

BACKGROUND

Feed-forward loops (FFLs), consisting of miRNAs, transcription factors (TFs) and their common target genes, have been validated to be important for the initialization and development of complex diseases, including cancer. Esophageal Carcinoma (ESCA) and Stomach Adenocarcinoma (STAD) are two types of malignant tumors in the digestive tract. Understanding common and distinct molecular mechanisms of ESCA and STAD is extremely crucial.

RESULTS

In this paper, we presented a computational framework to explore common and distinct FFLs, and molecular biomarkers for ESCA and STAD. We identified FFLs by combining regulation pairs and RNA-seq data. Then we constructed disease-specific co-expression networks based on the FFLs identified. We also used random walk with restart (RWR) on disease-specific co-expression networks to prioritize candidate molecules. We identified 148 and 242 FFLs for these two types of cancer, respectively. And we found that one TF, E2F3 was related to ESCA, two genes, DTNA and KCNMA1 were related to STAD, while one TF ESR1 and one gene KIT were associated with both of the two types of cancer.

CONCLUSIONS

This proposed computational framework predicted disease-related biomolecules effectively and discovered the correlation between two types of cancers, which helped develop the diagnostic and therapeutic strategies of Esophageal Carcinoma and Stomach Adenocarcinoma.

Diagnostic and prognostic value of lncRNA cancer susceptibility candidate 9 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignant gastrointestinal tumor. There are currently few clinical diagnostic and prognostic markers for HCC. LncRNA cancer susceptibility candidate 9 (CASC9) is a long-chain non-coding RNA discovered in recent years, and previous studies have found that lncRNA CASC9 participates in the occurrence and development of HCC, but its clinical value remains unclear.

AIM

To determine the expression of lncRNA CASC9 in HCC and its diagnostic and prognostic value.

METHODS

Data on CASC9 expression in patients with HCC were collected from the Cancer Genome Atlas (TCGA) database to analyze the relationship between CASC9 and patient survival. A total of 80 HCC patients treated in The First Affiliated Hospital of Guangxi Medical University from May 2012 to January 2014 were enrolled in the patient group, and 50 healthy subjects were enrolled in the control group during the same period. CASC9 expression in the two groups was determined using quantitative real-time polymerase chain reaction, and its diagnostic and prognostic value was analyzed based on the CASC9 data and pathological data in these HCC patients. The relationship between CASC9 and patient survival was assessed during the 5-year follow-up period.

RESULTS

Analysis of data from TCGA database revealed that control samples showed significantly lower CASC9 expression than carcinoma tissue samples (P < 0.001); the low CASC9 expression group had a higher survival rate than the high CASC9 expression group (P = 0.011), and the patient group showed significantly increased expression of serum CASC9, with the area under the curve (AUC) of 0.933. CASC9 expression was related to tumor size, combined hepatitis, tumor, node, metastasis (TNM) staging, lymph node metastasis, differentiation and alpha fetoprotein, and the high CASC9 expression group showed lower 1-year, 3-year and 5-year survival rates than the low CASC9 expression group (all ^aP < 0.05). Multivariate Cox regression analysis revealed that TNM staging, lymph node metastasis, differentiation, alpha fetoprotein and CASC9 were independent factors affecting the prognosis of patients. Stage I+II patients with lymph node metastasis, low differentiation, and alpha fetoprotein > 200 ng/mL had a poor 5-year survival rate.

CONCLUSION

High CASC9 expression is beneficial in the prognosis of HCC patients. CASC9 is expected to be a potential diagnostic and prognostic indicator of HCC.

Silencing lncRNAs PVT1 Upregulates miR-145 and Confers Inhibitory Effects on Viability, Invasion, and Migration in EC

Long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is correlated to various malignant tumors. Consequently, we explored effects of lncRNA PVT1 on esophageal carcinoma (EC) targeting microRNA-145 (miR-145). EC tissues, adjacent normal tissues, and EC-related cell lines were collected and cultured. Expression of lncRNA PVT1, miR-145, fascin-1 (FSCN1), and related genes with intervening expression of PVT1 and miR-145 was determined. Bioinformatic website, dual-luciferase reporter assay, and RNA immunoprecipitation (RIP) were carried to verify target relationship among lncRNA PVT1, FSCN1, and miR-145. Scratch test, Transwell assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and flow cytometry were performed for detection of migration, invasion, viability, and apoptosis of transfected cells, respectively. Finally, tumor formation in nude mice was measured. After database analysis, lncRNA PVT1, miR-145, and FSCN1 were selected for study. lncRNA PVT1 and FSCN1 can bind to miR-145. After overexpressing miR-145 or inhibiting lncRNA PVT1, EC cell viability, migration, and invasion were inhibited, while volume and weight of tumor formation in nude mice decreased. Expression of lncRNA PVT1, FSCN1, Bcl-2, CD147, VEGFR2, and MTA1 decreased and expression of miR-145 and Bax increased. Silencing lncRNA PVT1 can upregulate miR-145, which is a tumor suppressor in EC via knockdown of FSCN1. Thus, we might provide a potential theoretical basis for EC treatment.

Down-regulation of long noncoding RNA PVT1 inhibits esophageal carcinoma cell migration and invasion and promotes cell apoptosis via microRNA-145-mediated inhibition of FSCN1

Accumulating evidence has established that long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is a tumor regulator in many cancers. Here, we aimed to investigate the possible function of lncRNA PVT1 in esophageal carcinoma (EC) via targeting of microRNA-145 (miR-145). Initially, microarray-based gene expression profiling of EC was employed to identify differentially expressed genes. Moreover, the expression of lncRNA PVT1 was examined and the cell line presenting with the highest level of lncRNA PVT1 expression was selected for subsequent experiments. We then proceeded to examine interaction among lncRNA PVT1, FSCN1, and miR-145. The effect of lncRNA PVT1 on viability, migration, invasion, apoptosis, and tumorigenesis of transfected cells was examined with gain-of-function and loss-of-function experiments. We observed that lncRNA PVT1 was robustly induced in EC. lncRNA PVT1 could bind to miR-145 and regulate its expression, and FSCN1 is a target gene of miR-145. Overexpression of miR-145 or silencing of lncRNA PVT1 was revealed to suppress cell viability, migration, and invasion abilities, while also stimulating cell apoptosis. Furthermore, our in vivo results showed that overexpression of miR-145 or silencing of lncRNA PVT1 resulted in decreased tumor growth in nude mice. In conclusion, our research reveals that down-regulation of lncRNA PVT1 could potentially promote expression of miR-145 to repress cell migration and invasion, and promote cell apoptosis through the inhibition of FSCN1. This highlights the potential of lncRNA PVT1 as a therapeutic target for EC treatment.

P53-regulated lncRNA uc061hsf.1 inhibits cell proliferation and metastasis in human esophageal squamous cell cancer

The expression of long noncoding RNAs (lncRNAs) is closely associated with cancer development and progression, making these lncRNAs potentially novel therapeutic targets. In this study, we aimed to explore the potential function of lncRNA-uc061hsf.1 in esophageal squamous cell carcinoma (ESCC). The expression of lncRNA-uc061hsf.1 in ESCC tissues and cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, apoptosis, and metastasis were detected via CCK-8, flow cytometry, and Transwell assays. The interaction between p53 and lncRNA uc061hsf.1 was analyzed using luciferase reporter gene and qRT-PCR. Through this approach, we identified the novel lncRNA uc061hsf.1, which was expressed in low level in ESCC and was correlated with lymph node metastasis and poor differentiation in ESCC patients. Knockdown or overexpression of lncRNA uc061hsf.1 in ESCC cells promoted or inhibited cell proliferation and metastasis, respectively. Mechanistically, lncRNA uc061hsf.1 was induced by p53, and luciferase reporter gene confirmed that lncRNA uc061hsf.1 was a direct transcriptional target of p53. We further found that uc061hsf.1 was able to regulate expression of the transcription factor FoxA1, thereby potentially influencing tumor cell migration. In conclusion, these results suggest that p53-regulated lncRNA uc061hsf.1 is a cancer suppressor gene which is associated with tumor progression in ESCC.

A seven long-noncoding RNA signature predicts prognosis of lung squamous cell carcinoma

Aim: This study profiled differentially expressed long noncoding RNAs (lncRNAs) in lung squamous cell carcinoma (LSCC) to predict LSCC overall survival (OS) using The Cancer Genome Atlas data. Materials & methods: The RNA-seq and clinical dataset of 475 LSCC patients was retrieved from The Cancer Genome Atlas database and statistically analyzed. Results: There were 67 upregulated and 32 downregulated lncRNAs in LSCCs and 12 lncRNAs associated with OS. The seven-lncRNA signature was associated with poor OS and RP11-150O12.6 and CTA-384D8.35 were associated with better OS (p < 0.001). The seven lncRNAs-mRNA interaction network analysis showed their association with 187 protein-coding genes for cancer development, cell migration, adhesion, proliferation, apoptosis, angiogenesis and the MAPK signaling pathways. Conclusion: This seven-lncRNA signature is useful to predict LSCC OS.

Long non-coding RNA CASC9 knockdown inhibits the progression of nasopharyngeal carcinoma by regulating miR-145

BACKGROUND

Long non-coding RNAs (lncRNAs) have been widely confirmed to modulate many tumorigeneses, including NPC. However, the exact roles of cancer susceptibility candidate 9 (CASC9) in nasopharyngeal carcinoma (NPC) and its underlying mechanisms have not been fully established.

METHODS

qRT-PCR was used to determine CASC9 and miR-145 expressions. Cell apoptosis, migration, and invasion were determined by flow cytometry and transwell assays, respectively. The protein expressions of BAX, Bcl-2, MMP 9, and MMP 2 were measured by western blot. The possible binding sites between miR-145 and CASC9 were predicted by the starBase v2.0 online database and verified by a luciferase report and an RNA immunoprecipitation (RIP) assay. A xenograft tumor model was established to confirm the effects of CASC9 in NPC progression in vivo.

RESULTS

The expression level of CASC9 was upregulated in NPC tissues and cells. The knockdown of CASC9 evidently suppressed migration and invasion but promoted apoptosis in NPC cells. In addition, the inhibition of CASC9 evidently increased the BAX protein level and inhibited the expression of the Bcl-2, MMP 9, and MPP2 proteins in NPC cells. Moreover, miR-145 was directly bound to CASC9, and its inhibition reversed the inhibitory effect of CASC9 knockdown on the progression of NPC. Furthermore, the expression of miR-145 was decreased and negatively associated with CASC9 in NPC tissues and cells. Also, the knockdown of CASC9 inhibited tumor growth in vivo.

CONCLUSION

CASC9 knockdown inhibited cell migration and invasion but increased cell apoptosis in NPC cells by regulating miR-145, providing a novel insight for the treatment of NPC.

Long Non-Coding RNA CASC9 And HIF-1α Form A Positive Feedback Loop To Facilitate Cell Proliferation And Metastasis In Lung Cancer

Background

The long noncoding RNA cancer susceptibility 9 (CASC9) has been recognized as an important modulator of cell growth and metastasis in many cancers. However, its detailed roles in lung cancer remain unclear. In this study, we aimed to investigate its functions and molecular mechanism in lung cancer progression.

Methods

Expression of CASC9 was determined in lung cancer tissues and cell lines by real-time PCR. CCK-8, colony formation, wound healing and transwell assays were done to evaluate the cell proliferation, migration and invasion capacities in vitro. Real-time PCR, Western blot and RNA immunoprecipitation (RIP) assays were performed to dissect the mechanisms.

Results

CASC9 was overexpressed in lung cancer specimens and cell lines. Knockdown of CASC9 inhibited cell proliferation, migration, invasion and EMT in lung cancer cells. While overexpression of CASC9 in normal lung epithelial cells did the opposite. CASC9 interacted with HIF-1α and enhanced its protein stability. They formed a positive feedback loop by reciprocally inducing each other expression and regulated cell proliferation and metastasis.

Conclusion

Our findings demonstrated a novel regulatory signaling pathway, namely the CASC9/HIF-1α axis, which was involved in lung cancer progression. These findings can provide valuable insights on the potential therapy application for lung cancer.

GLUT-1 participates in the promotion of LncRNA CASC9 in proliferation and metastasis of laryngeal carcinoma cells

Increasing evidence indicates that long non-coding RNA (lncRNA) may play important roles in tumorigenesis. Increased lncRNA CASC9 occurs in laryngeal carcinoma, which accounts for 20% of all head and neck cancers, but its role in this disease remains unknown. Using quantitative reverse transcriptase PCR, we found higher expression of CASC9 and GLUT-1 in laryngeal carcinoma tissues and cells, compared to adjacent tissues and cells. A correlation analysis showed a positive relationship between CASC9 and GLUT-1 expression in laryngeal carcinoma tissues. An MTT assay of TU212 and Hep-2 cells showed increased cell proliferation after transfection with overexpressed CASC9 and decreased cell proliferation after transfection with silenced CASC9. A Transwell assay showed that overexpressing CASC9 increased and silencing CASC9 decreased cell migration of TU212 and Hep-2 cells. A flow cytometry assay showed that overexpressing CASC9 reduced and silencing CASC9 increased cell apoptosis. In other words, we found that overexpressing CASC9 increased cell proliferation and cell migration and decreased apoptosis both in TU212 and Hep-2 cells, whereas silencing CASC9 had the opposite effects. Moreover, overexpression vector of GLUT-1 was used to investigate the molecular mechanism of CASC9 in laryngeal carcinoma. The results showed that transfection with an overexpressed GLUT-1vector reversed the effects of silencing CASC9 on proliferation, migration, and apoptosis in TU212 and Hep-2 cells. In conclusion, our study of laryngeal carcinoma found that CASC9 was positively correlated with GLUT-1 expression and that CASC9 may promote proliferation and metastasis of laryngeal carcinoma cells by regulating GLUT-1.

Upregulation of the long non-coding RNA CASC9 as a biomarker for squamous cell carcinoma

BACKGROUND

Few diagnostic and prognostic biomarkers are available for head-and-neck squamous cell carcinoma (HNSCC). Long non-coding RNAs (lncRNAs) have shown promise as biomarkers in other cancer types and in some cases functionally contribute to tumor development and progression. Here, we searched for lncRNAs useful as biomarkers in HNSCC.

METHODS

Public datasets were mined for lncRNA candidates. Two independent HNSCC tissue sets and a bladder cancer tissue set were analyzed by RT-qPCR. Effects of lncRNA overexpression or downregulation on cell proliferation, clonogenicity, migration and chemosensitivity were studied in HNSCC cell lines.

RESULTS

Data mining revealed prominently CASC9, a lncRNA significantly overexpressed in HNSCC tumor tissues according to the TCGA RNAseq data. Overexpression was confirmed by RT-qPCR analyses of patient tissues from two independent cohorts. CASC9 expression discriminated tumors from normal tissues with even higher specificity than HOTAIR, a lncRNA previously suggested as an HNSCC biomarker. Specificity of HNSCC detection by CASC9 was further improved by combination with HOTAIR. Analysis of TCGA pan-cancer data revealed significant overexpression of CASC9 across different other entities including bladder, liver, lung and stomach cancers and especially in squamous cell carcinoma (SCC) of the lung. By RT-qPCR analysis we furthermore detected stronger CASC9 overexpression in pure SCC of the urinary bladder and mixed urothelial carcinoma with squamous differentiation than in pure urothelial carcinomas. Thus, CASC9 might represent a general diagnostic biomarker and particularly for SCCs. Unexpectedly, up- or downregulation of CASC9 expression in HNSCC cell lines with low or high CASC9 expression, respectively, did not result in significant changes of cell viability, clonogenicity, migration or chemosensitivity.

CONCLUSIONS

CASC9 is a promising biomarker for HNSCC detection. While regularly overexpressed, however, this lncRNA does not seem to act as a major driver of development or progression in this tumor.

Comprehensive bioinformatics analysis identifies lncRNA HCG22 as a migration inhibitor in esophageal squamous cell carcinoma

Esophageal cancer is one of the most lethal malignancies worldwide, and esophageal squamous cell carcinoma (ESCC) is the dominant histological type. However, the long noncoding RNA (lncRNA) alterations in ESCC have not been elucidated to date. In this study, reliable databases from Gene Expression Omnibus (GEO), which analyzed lncRNA expression in ESCC tumor tissues and adjacent normal tissues were searched, and common differentially expressed lncRNAs and genes were analyzed. Next, cis- trans analysis was performed to predict the underlying relationships between altered lncRNAs and mRNAs, and the lncRNA-mRNA regulatory network was established. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of altered lncRNA-related genes were performed. The promising lncRNA HCG22 was validated by quantitative polymerase chain reaction (qPCR), and clinicopathological data were collected to identify the relationship between lncRNA HCG22 expression level and clinical features. Finally, Transwell assays were performed to explore the biological functions of lncRNA HCG22 in ESCC cells. Two hundred forty-one lncRNAs and 835 mRNAs were observed to be remarkably altered between ESCC tumor tissues and adjacent normal tissues. The lncRNA-mRNA regulatory network showed the coexpression association between lncRNA HCG22 and SPINK7 and ADAMTS12. GO and KEGG analyses showed that HCG22 and ADAMTS12 had potential biological functions in the cell migration of ESCC. The downregulation of lncRNA HCG22 in ESCC tumor tissues was validated by qPCR, and the clinicopathological data showed a noticeable correlation between lncRNA HCG22 expression level and the ESCC differentiational degree and clinical TNM stage. Kaplan-Meier analysis showed that patients with ESCC having low lncRNA HCG22 expression in ESCC tissues had considerably shorter overall survival compared with patients with ESCC having high lncRNA HCG22 expression. Following Transwell assays confirmed the migratory role of lncRNA HCG22 in ESCC cells. In conclusion, lncRNA HCG22 was downregulated in ESCC tissues and can be a migration inhibitor of ESCC cells, and SPINK7 and ADAMTS12 are promising to be the regulatory targets of lncRNA HCG22.

Long non-coding RNA CASC9 enhances breast cancer progression by promoting metastasis through the meditation of miR-215/TWIST2 signaling associated with TGF-β expression

Accumulating study has indicated that long non-coding RNAs (lncRNAs) could serve as critical modulators to meditate tumor metastasis. In the study, the crucial role of lncRNA cancer susceptibility candidate 9 (CASC9) in regulating cervical cancer metastasis and progression was investigated. CASC9 expression was markedly increased in cervical cancer tissues and cell lines. Cervical cancer patients with low CASC9 expression showed better overall survival rate. Moreover, cancer-associated fibroblasts (CAFs)-derived transforming growth factor β (TGF-β) could increase CASC9 expression. The crosslink between CAFs and cervical cancer cells led to CASC9 to elevate the metastasis of cervical cancer cells. CASC9 dysregulation could function as a miRNA sponge to competitively protect twist homolog 2 (TWIST2) mRNA 3'UTR from miR-215. Results in this study indicated the effects of CASC9 on cervical cancer and suggested a novel axis by which CASC9 meditated cervical cancer cell metastasis and proliferation both in vivo and in vitro. Together, CASC9 could be a prognostic marker for cervical cancer to develop effective therapeutic treatment against cervical cancer growth.

Bioinformatics identification of lncRNA biomarkers associated with the progression of esophageal squamous cell carcinoma

The poor outcome of patients with esophageal squamous cell carcinoma (ESCC) highlights the importance of the identification of novel effective prognostic biomarkers. Long non-coding RNAs (lncRNAs) serve regulatory roles in various types of cancer. The aim of the present study was to investigate the lncRNA expression profile in ESCC and to identify lncRNAs associated with the prognosis of ESCC by performing comprehensive bioinformatics analyses. The RNA-sequencing (Seq) expression dataset GSE53625 generated from ESCC samples was used as a training dataset. Additional RNA-Seq datasets relative to ESCC samples were downloaded from The Cancer Genome Atlas and used as a validation dataset. Data were screened using the limma package, and differentially expressed lncRNAs between early- and late-stage ESCC were identified. A random forest algorithm was used to select the optimal lncRNA biomarkers, which were then analyzed using the support vector machine (SVM) algorithm with R software. The identified lncRNA biomarkers were examined in the validation dataset by bidirectional hierarchical clustering and using an SVM classifier. Subsequently, univariate and multivariate Cox regression analyses were performed to analyze the potential ability lncRNAs to predict the survival rate of patients with ESCC. By examining the training group, 259 deregulated lncRNAs between early- and advanced-stage ESCC were identified. Further bioinformatics analyses identified a nine-lncRNA signature, including AC098973, AL133493, RP11-51M24, RP11-317N8, RP11-834C11, RP11-69C17, LINC00471, LINC01193 and RP1-124C. This nine-lncRNA signature was used to predict the tumor stage and patient survival rate with high reliability and accuracy in the training and validation datasets. Furthermore, these nine lncRNA biomarkers were primarily involved in regulating the cell cycle and DNA replication, and these processes were previously identified to be associated with the progression of ESCC. The identified nine-lncRNA signature was identified to be associated with the tumor stage, and could be used as predictor of the survival rate of patients with ESCC.

Identifying potential metastasis-related long non-coding RNAs, microRNAs, and message RNAs in the esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the predominant form with the highest incidence. We aimed to find metastasis-related differentially expressed long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNA (mRNAs) in ESCC. We first obtained the lncRNAs, miRNAs, and mRNAs profiles. The differentially expressed lncRNAs, miRNAs, and mRNAs were obtained, followed by the functional annotation. Then the interaction networks of miRNA-mRNA, lncRNA-mRNA coexpression, lncRNA-miRNA, and lncRNA-miRNA-mRNA were constructed. In addition, systematic expression pattern analysis of differentially expressed lncRNAs, miRNA, and mRNA in the normal, metastasis, and nonmetastasis was performed. Survivability of differentially expressed lncRNAs, miRNAs, and mRNA was analyzed. A total of 613 differentially expressed lncRNAs, 35 differentially expressed miRNAs, and 1586 differentially expressed mRNAs were obtained. Several interactions of H19-hsa-mir-222-chromobox 2 (CBX2), H19-hsa-mir-330-phosphoinositide-3-kinase regulatory subunit 4 (PIK3R4), KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1)/CTB-89H12.4-hsa-mir-374a-vascular endothelial growth factor A (VEGFA), MALAT1/X inactive specific transcript (XIST)/XIST antisense RNA (TSIX)-hsa-mir-340-tumor necrosis factor receptor superfamily member 10A (NFRSF10A) were identified to play key roles in the metastasis of ESCC. In addition, KCNQ1OT1, TSIX, and XIST were significantly associated with the survival time of patients. In conclusion, our study may be helpful in understanding the pathological mechanism and providing new diagnostic and therapeutic biomarkers for ESCC.

lncRNA CASC9 positively regulates CHK1 to promote breast cancer cell proliferation and survival through sponging the miR‑195/497 cluster

Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) play important roles in the pathogenesis and development of diverse types of human disorders. Cancer susceptibility candidate 9 (CASC9), a gene encoding a lncRNA, has frequently been reported to be dysregulated and has been implicated in multiple types of human malignancies. However, the biological role of lncRNA CASC9 in breast cancer (BC) remains largely unknown. The present study aimed to investigate the role of lncRNA CASC9 in BC and to elucidate the potential molecular mechanisms involved. In the present study, lncRNA CASC9 was found to be significantly upregulated in both BC tissues and cell lines. Furthermore, functional analyses revealed that lncRNA CASC9 accelerated BC cell proliferation, promoted cell cycle progression and suppressed cell apoptosis. Moreover, mechanical experiments demonstrated that lncRNA CASC9 positively regulated checkpoint kinase 1 (CHK1) by competitively binding to the miR-195/497 cluster in BC cells. Additionally, the knockdown of lncRNA CASC9 was observed to suppress breast tumor growth in vivo. Taken together, the results of this study indicate that lncRNA CASC9 plays an oncogenic role in BC through sponging the miR-195/497 cluster, and that lncRNA CASC9 may be used as a novel therapeutic target and as a potential diagnostic marker for BC.