Long non-coding RNA CASC15 promotes tongue squamous carcinoma progression through targeting miR-33a-5p

IGFL2-AS1 facilitates tongue squamous cell carcinoma progression via Wnt/β-catenin signaling pathway

OBJECTIVES

Tongue squamous cell carcinoma (TSCC) is the most common malignancy in oral cancer. Long noncoding RNAs (lncRNAs) are important regulators in cancer biology. In our present study, we investigated a novel lncRNA IGF-like family member 2 antisense RNA 1 (IGFL2-AS1) in TSCC.

METHODS

RT-qPCR analyzed IGFL2-AS1 expression in TSCC cells. Functional assays assessed the impact of IGFL2-AS1 on TSCC cell proliferation, migration, and invasion. Western blot analyzed the protein levels of EMT-related markers. Mechanism assays analyzed the regulatory mechanism of IGFL2-AS1 in TSCC cells. In-vivo experiments were conducted to prove the role of IGFL2-AS1 in TSCC progression.

RESULTS

IGFL2-AS1 was significantly up-regulated in TSCC cells and tissues, and IGFL2-AS1 knockdown inhibited cell proliferation, migration, invasion and EMT in TSCC. Moreover, IGFL2-AS1 functioned as a competing endogenous RNA (ceRNA) to sponge miR-1224-5p and thereby modulated SATB homeobox 1 (SATB1) expression. Additionally, SATB1 activated the Wnt/β-catenin signaling pathway in TSCC cells and IGFL2-AS1 regulated the Wnt/β-catenin signaling pathway and TSCC progression via elevating SATB1 expression.

CONCLUSIONS

The data revealed that IGFL2-AS1 played a cancer promoting role in TSCC and may aid in exploring a brand new biomarker that might contribute to TSCC treatment.

A study of the prognostic value of long non-coding RNA CASC15 in human solid tumors utilizing The Cancer Genome Atlas (TCGA) datasets and a meta-analysis

BACKGROUND AND AIMS

Several malignant solid tumors have been reported to have an abnormal expression of the long non-coding RNA CASC15 (lncRNA CASC15). However, the clinicopathologic and prognostic importance of CASC15 in solid tumors are unknown. As a result, we examined the interrelationship between CASC15, overall survival length, and clinicopathological attributes of cancers affecting humans by analyzing various studies and The Cancer Genome Atlas (TCGA) data related to CASC15 expression.

METHODS

Web of Science, PubMed, Cochrane Library, Embase, Chinese WanFang, and Chinese CNKI databases were used to conduct a literature search. Hazard ratios (HRs) and Pooled odds ratios (ORs) were calculated taking 95% confidence intervals (CIs). The results of the current meta-analysis were further validated using TCGA datasets.

RESULTS

A total of 12 eligible studies enrolling 767 patients were included in this meta-analysis. Findings of the analysis showed that CASC15 expression had a significant relation to the metastasis of lymph node (OR = 3.30, 95%CI = 1.88-5.81, p < 0.001), distant metastasis (OR = 2.64, 95%CI = 1.24-5.63, p = 0.012), and high TNM/clinical stage (OR = 2.67, 95%CI = 1.34-5.32, p = 0.005). Additionally, we found that a poor outcome for overall survival (OS) was predicted by an elevation in CASC15 expression (HR = 2.01, 95%CI = 1.71-2.36, p < 0.001). Further investigation of the TCGA dataset revealed that CASC15 had abnormal expression in many cancers, which at least partially validated the findings of the current meta-analysis.

CONCLUSIONS

According to the latest meta-analysis and systematic review, high expression levels of CASC15 are associated with poor survival outcomes for solid tumor patients, and the use of CASC15 as a solid tumor prognostic predictor has a solid theoretical foundation.

Dysregulation and implications of lncRNAs and miRNAs in oral tongue squamous cell carcinoma: In reply with emphasis on the role of ceRNAs

Increasing evidence indicates that long noncoding RNAs (lncRNAs) as competing endogenous RNAs (ceRNAs) competitively sequestering microRNAs (miRNAs) participate in biological processes of oral tongue squamous cell carcinoma (TSCC). In this Letter, the ceRNA regulatory networks consisting of lncRNA/miRNA/mRNA axes in TSCC were summarized. Dysregulated profiles containing 33 lncRNAs and 31 miRNAs were identified by cancer-associated phenotypes verification. Almost all the lncRNAs could exert the oncogenic roles to sponge miRNAs and regulate targeting mRNA expression, thereby modulating cell proliferation, cell cycle, apoptosis, invasion, migration, metastasis, epithelial-mesenchymal transition, as well as chemoresistance. Significantly, the implications of functional ceRNAs deactivated in tumor cells contribute to the exploitation of novel diagnostic and therapeutic strategies for TSCC.

Circulating Long Non-Coding RNAs Could Be the Potential Prognostic Biomarker for Liquid Biopsy for the Clinical Management of Oral Squamous Cell Carcinoma

Long non-coding RNA (lncRNA) have little or no coding potential. These transcripts are longer than 200 nucleotides. Since lncRNAs are master regulators of almost all biological processes, recent evidence proves that aberrantly expressed lncRNAs are pathogenic for oral squamous cell carcinoma (OSCC) and other diseases. LncRNAs influence chromatin modifications, transcriptional modifications, post-transcriptional modifications, genomic imprinting, cell proliferation, invasion, metastasis, and apoptosis. Consequently, they have an impact on the disease transformation, progression, and morbidity in OSCC. Therefore, circulating lncRNAs could be the potential cancer biomarker for the better clinical management (diagnosis, prognosis, and monitoring) of OSCC to provide advanced treatment strategies and clinical decisions. In this review, we report and discuss the recent understandings and perceptions of dysregulated lncRNAs with a focus on their clinical significance in OSCC-disease monitoring and treatment. Evidence clearly indicates that a specific lncRNA expression signature could act as an indicator for the early prediction of diagnosis and prognosis for the initiation, progression, recurrence, metastasis and other clinical prognostic-factors (overall survival, disease-free survival, etc.) in OSCC. The present review demonstrates the current knowledge that all potential lncRNA expression signatures are molecular biomarkers for the early prediction of prognosis in OSCC. Finally, the review provides information about the clinical significance, challenges and limitations of the clinical usage of circulating lncRNAs in a liquid biopsy method in early, pre-symptomatic, sub-clinical, accurate OSCC prognostication. More studies on lncRNA are required to unveil the biology of the inherent mechanisms involved in the process of the development of differential prognostic outcomes in OSCC.

Clinical Value and Potential Mechanism of miRNA-33a-5p in Lung Squamous Cell Carcinoma

This study is aimed at thoroughly exploring the expression status, clinical significance, and underlying molecular mechanism of miRNA-33a-5p in lung squamous cell carcinoma (LUSC). Here, we detected miRNA-33a-5p in 20 samples from patients with LUSCs and 20 matching non-LUSC specimens by in-house quantitative real-time PCR (RT-qPCR). Relationship between miRNA-33a-5p expression and clinicopathological traits was investigated from materials derived from miRNA sequencing and miRNA microarrays. A pool standard mean difference (SMD) and summary receiver operating characteristic curves (SROC) were calculated to evaluate the integrated expression value of miRNA-33a-5p in LUSC. Twelve online platforms were applied to select potential target genes of miRNA-33a-5p. The differentially expressed genes (DEGs) of LUSC and the candidate target genes of miRNA-33a-5p were overlapped to acquire a set of specific genes for further analyses of the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and protein–protein interaction (PPI) network. miRNA-33a-5p overexpressed in LUSC was supported by 706 LUSC and 261 non-LUSC samples gathering from RT-qPCR, miRNA-seq, and public miRNA microarrays. The pooled SMD was 0.56 (95% CI: -0.01-1.05), and the area under the curve (AUC) of the SROC was 0.78 (95% CI: 0.74-0.82). A total of 240 genes were identified as potential target genes of miRNA-33a-5p for functional enrichment analyses; the results suggested that these target genes may participate in several vital biological processes that promote the proliferation and progression of LUSC. miRNA-33a-5p may play an essential role in the occurrence and development of LUSC by targeting hub genes (ETS1, EDNRB, CYR61, and LRRK2) derived from the PPI network. In summary, our results indicated that miRNA-33a-5p may contribute as a prospective therapeutic target in LUSC.

Long Non-Coding RNA (lncRNA) in Oral Squamous Cell Carcinoma: Biological Function and Clinical Application

Simple Summary

Increasing evidence has revealed the regulatory roles of long non-coding RNAs (lncRNAs) in the initiation and progress of oral squamous cell carcinoma (OSCC). As some novel lncRNA-targeted techniques combined with immune checkpoint therapies have emerged, they provide a new strategy for OSCC treatment. This review summarizes current knowledge regarding the involvement of lncRNAs in OSCC along with their possible use as diagnostic and prognostic biomarker and therapeutic targets.

Abstract

Oral squamous cell carcinoma (OSCC) is a type of malignancy with high mortality, leading to poor prognosis worldwide. However, the molecular mechanisms underlying OSCC carcinogenesis have not been fully understood. Recently, the discovery and characterization of long non-coding RNAs (lncRNAs) have revealed their regulatory importance in OSCC. Abnormal expression of lncRNAs has been broadly implicated in the initiation and progress of tumors. In this review, we summarize the functions and molecular mechanisms regarding these lncRNAs in OSCC. In addition, we highlight the crosstalk between lncRNA and tumor microenvironment (TME), and discuss the potential applications of lncRNAs as diagnostic and prognostic tools and therapeutic targets in OSCC. Notably, we also discuss lncRNA-targeted therapeutic techniques including CRISPR-Cas9 as well as immune checkpoint therapies to target lncRNA and the PD-1/PD-L1 axis. Therefore, this review presents the future perspectives of lncRNAs in OSCC therapy, but more research is needed to allow the applications of these findings to the clinic.

miR-33a-5p inhibits the progression of esophageal cancer through the DKK1-mediated Wnt/β-catenin pathway

Esophageal cancer (EC) is one of the most lethal malignancies in humans, and multiple miRNAs have been identified to modulate EC progression by targeting different targets. However, the effect and related mechanism of microRNA-33a-5p (miR-33a-5p) on EC development remain elusive. In this study, we explored the clinical value, function, and possible mechanism of miR-33a-5p in EC. We uncovered that miR-33a-5p and DKK1 are involved in the progression of EC. Significantly, the expression levels of miR-33a-5p were reduced and DKK1 levels were elevated in serum and tissues of clinical EC samples and in EC cell lines. The downregulation of miR-33a-5p and DKK1 upregulation were related to high TNM staging and poor differentiation of patients. The area under the curves (AUCs) of miR-33a-5p and DKK1 for the occurrence of EC were 0.914 and 0.900, respectively. Down-regulation of miR-33a-5p or overexpression of DKK1 indicated a worse prognosis. The miR-33a-5p overexpression or DKK1 depletion induced apoptosis and repressed proliferation, migration, and invasion of EC cells. The repression of miR-33a-5p by inhibitor or DKK1 overexpression presented the conversed effects on EC cells. Mechanically, miR-33a-5p suppressed DKK1 expression, and miR-33a-5p targeted DKK1 to affect the biological behavior of EC through the Wnt/β-catenin pathway. Meanwhile, miR-33a-5p inhibited the tumor growth of EC in vivo. Thus, we concluded that miR-33a-5p inhibited the progression of EC through the DKK1-mediated Wnt/β-catenin pathway. MiR-33a-5p and DKK1 can be used as potential therapeutic targets of EC.

LncRNA GACAT1 induces tongue squamous cell carcinoma migration and proliferation via miR-149

Recent studies have observed that lncRNAs (long non‐coding RNAs) are involved in the progression of various tumours including tongue squamous cell carcinoma (TSCC). Recently, a new lnRNA, GACAT1, has been firstly identified in gastric cancer. However, its potential role in TSCC remains unknown. In this reference, we observed that GACAT1 was overexpressed in TSCC samples and cell lines. Of 25 TSCC specimens, GACAT1 expression was overexpressed in 18 patients (18/25, 72%) compared to non‐tumour specimens. Ectopic expression of GACAT1 induced cell growth and migration and promoted epithelial to mesenchymal transition in TSCC. In addition, ectopic expression of GACAT1 decreased miR‐149 expression in SCC1 cell. We observed that miR‐149 expression was down‐regulated in TSCC cell lines. Moreover, we observed that GACAT1 expression was negatively correlated with miR‐149 expression. GACAT1 overexpression induced TSCC cell growth and migration via regulating miR‐149 expression. These data provided that GACAT1 played an oncogenic role in the progression of TSCC partly through modulating miR‐149 expression.

CASC15: A Tumor-Associated Long Non-Coding RNA

BACKGROUND

CASC15, one of long non-coding RNA, is involved in the regulation of many tumor biological processes, and is expected to become a new biological therapeutic target. This paper aims to elucidate the pathophysiological function of CASC15 in various tumors.

METHODS

The relationship between CASC15 and tumors was analyzed by searching references, and summarized the specific pathophysiological mechanism of CASC15.

RESULTS

LncRNA CASC15 is closely related to tumor development, and has been shown to be abnormally high expressed in all kinds of tumors, including breast cancer, cervical cancer, lung cancer, hepatocellular carcinoma, gastric cancer, bladder cancer, colon cancer, colorectal cancer, cardiac hypertrophy, intrahepatic cholangiocarcinoma, leukemia, melanoma, tongue squamous cell carcinoma and nasopharyngeal carcinoma. However, CASC15 has been found to be down-expressed abnormally in ovarian cancer, glioma and neuroblastoma. Besides, it is identified that CASC15 can affect the proliferation, invasion and apoptosis of tumors.

CONCLUSION

LncRNA CASC15 has the potential to become a new therapeutic target or marker for a variety of tumors.

lncRNA RPSAP52 induced the development of tongue squamous cell carcinomas via miR-423-5p/MYBL2

Growing lncRNAs have been noted to involve in the initiation and development of several tumours including tongue squamous cell carcinomas (TSCCs). However, the biological role and mechanism of lncRNA RPSAP52 were not well‐explained. We indicated that RPSAP52 was higher in TSCC samples compared with that in control samples. The higher expression of RPSAP52 was positively correlated with higher T stage and TNM stage. Ectopic expression of RPSAP52 induced TSCC cell growth and cycle and induced cytokine secretion including IFN‐γ, IL‐1β and IL‐6, IL‐8, IL‐10 and TGF‐β. We found that the overexpression of RPSAP52 suppressed miR‐423‐5p expression in SCC‐4 cell. miR‐423‐5p was lower in TSCC samples compared with that in control samples, and miR‐423‐5p level was negatively correlated with higher T stage and TNM stage. Pearson's correlation indicated that miR‐423‐5p was negatively associated with that of RPSAP52 in TSCC tissues. Furthermore, MYBL2 was one direct gene of miR‐423‐5p and elevated expression of miR‐423‐5p suppressed MYBL2 expression and ectopic expression of RPSAP52 increased MYBL2 expression in SCC‐4 cell. Finally, we illustrated that RPSAP52 overexpression promoted TSCC cell growth and cycle and induced cytokine secretion including IFN‐γ, IL‐1β and IL‐6, IL‐8, IL‐10 and TGF‐β via modulating MYBL2. These data provided new insight into RPSAP52, which may be one potential treatment target for TSCC.

The dual functions of the long noncoding RNA CASC15 in malignancy

Emerging evidence has demonstrated that long noncoding RNAs (lncRNAs) play vital roles in tumorigenesis and progression. LncRNAs can participate in various biological processes, such as cell growth, anti-apoptosis functions, migration, and invasion. Cancer susceptibility candidate 15 (CASC15) is a cancer-related lncRNA that has been reported to play opposite roles in the pathogenesis of different types of cancers. Studies have shown that CASC15 is downregulated in ovarian cancer and neuroblastoma, acting mainly as a tumour suppressor, while it is highly expressed and carcinogenic in hepatocellular carcinoma (HCC), lung cancer, tongue squamous cell carcinoma, gastric cancer, colorectal cancer, cervical cancer, and breast cancer. Furthermore, aberrant CASC15 expression is associated with tumorigenesis, progression, and patient outcomes via regulation of target genes and signalling pathways. In this review, we summarize current data concerning the regulatory functions and underlying mechanisms of CASC15 in tumour development. We also highlight its potential clinical utility as a biomarker for early detection or as a therapeutic target in human cancers.

Long Noncoding RNAs in the Metastasis of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignant tumor worldwide. Metastasis is the main cause of the death of OSCC patients. Long noncoding RNAs (lncRNAs), one of the key factors affecting OSCC metastasis, are a subtype of RNA with a length of more than 200 nucleotides that has little or no coding potential. In recent years, the important role played by lncRNAs in biological processes, such as chromatin modification, transcription regulation, RNA stability regulation, and mRNA translation, has been gradually revealed. More and more studies have shown that lncRNAs can regulate the metastasis of various tumors including OSCC at epigenetic, transcriptional, and post-transcriptional levels. In this review, we mainly discussed the role and possible mechanisms of lncRNAs in OSCC metastasis. Most lncRNAs act as oncogenes and only a few lncRNAs have been shown to inhibit OSCC metastasis. Besides, we briefly introduced the research status of cancer-associated fibroblasts-related lncRNAs in OSCC metastasis. Finally, we discussed the research prospects of lncRNAs-mediated crosstalk between OSCC cells and the tumor microenvironment in OSCC metastasis, especially the potential research value of exosomes and lymphangiogenesis. In general, lncRNAs are expected to be used for screening, treatment, and prognosis monitoring of OSCC metastasis, but more work is still required to better understand the biological function of lncRNAs.

Role of microRNA-33a in malignant cells

Cancer causes most of the mortality and morbidity worldwide, with a significant increase in incidence during recent years. MicroRNAs (miRNAs/miRs) are non-coding small RNAs capable of regulating gene expression. They regulate crucial cellular processes, including proliferation, differentiation, metastasis and apoptosis. Therefore, abnormal miRNA expression is associated with multiple diseases, including cancer. There are two types of cancer-associated miRNAs, oncogenic and tumor suppressor miRNAs, depending on their roles and expression patterns in cancer. Accordingly, miRNAs are considered to be targets for cancer prevention and treatment. miR-33a controls cellular cholesterol uptake and synthesis, which are both closely associated with carcinogenesis. The present review thoroughly describes the roles of miR-33a in more than a dozen types of cancer and the underlying mechanisms. Accordingly, the present review may serve as a guide for researchers studying the involvement of miR-33a in diverse cancer settings.

Long non‑coding RNA PRNCR1 exerts oncogenic effects in tongue squamous cell carcinoma in vitro and in vivo by sponging microRNA‑944 and thereby increasing HOXB5 expression

A long non-coding RNA (lncRNA) called prostate cancer-associated non-coding RNA 1 (PRNCR1) serves crucial roles in the aggressive phenotypes of colorectal cancer and non-small cell lung cancer. However, there is little research on the expression profile, clinical value and detailed functions of PRNCR1 in tongue squamous cell carcinoma (TSCC). The aim of the present study was to determine PRNCR1 expression in TSCC and to examine the involvement of PRNCR1 in TSCC progression. The molecular mechanisms behind the oncogenic effects of PRNCR1 in TSCC cells were also investigated. PRNCR1 was revealed to be upregulated in TSCC tumors and cell lines. The high PRNCR1 expression showed a significant correlation with tumor size, clinical stage, lymph node metastasis, and shorter overall survival times among patients with TSCC. A PRNCR1-knockdown reduced TSCC cell proliferation, migration and invasion, and increased apoptosis in vitro. Additionally, the PRNCR1-knockdown slowed down in vivo tumor growth of TSCC cells. With regards to the mechanism, PRNCR1 acted as a competing endogenous RNA on microRNA-944 (miR-944) in TSCC cells, and the effects of the PRNCR1-knockdown were reversed by an miR-944-knockdown. HOXB5 was validated as a direct target gene of miR-944 in TSCC cells, and HOXB5 expression was found to be positively regulated by PRNCR1. Furthermore, resumption of HOXB5 expression reversed the tumor-suppressive actions of miR-944 in TSCC cells. In conclusion, PRNCR1 acts as an oncogenic lncRNA in TSCC through the upregulation of HOXB5 by sponging miR-944, thereby indicating a potential therapeutic target in TSCC.

Long Non-Coding RNA EGOT Promotes the Malignant Phenotypes of Hepatocellular Carcinoma Cells and Increases the Expression of HMGA2 via Down-Regulating miR-33a-5p

Background

Chronic hepatitis C virus (HCV) infection is an important risk factor for hepatocellular carcinoma (HCC). EGOT is a long non-coding RNA (lncRNA) induced after HCV infection that increases viral replication by antagonizing the antiviral response. Interestingly, EGOT also acts as a crucial regulator in multiple cancers. However, its role in HCC remains unclear.

Methods

Real-time PCR (RT-PCR) was used to detect the expression of EGOT in HCC samples and cell lines. CCK-8 assay and colony formation assay were performed to evaluate the effect of EGOT on proliferation. Scratch healing assay and transwell assay were used to detect the changes of migration and invasion. Flow cytometry was used to detect the effect of EGOT on apoptosis. Interaction between EGOT and miR-33a-5p was determined by bioinformatics analysis, RT-PCR, and dual-luciferase reporter assay. Western blot was used to confirm that high mobility group protein A2 (HMGA2) could be modulated by EGOT.

Results

Compared with normal liver tissues, the expression level of EGOT in HCC tissues was significantly up-regulated. EGOT markedly regulated viability, migration and invasion of HCC cells. The expression level of EGOT was negatively correlated the expression level of miR-33a-5p. It is also confirmed that EGOT could specifically bind to miR-33a-5p and could reduce its expression, in turn, up-regulate the expression of HMGA2.

Conclusion

Our data imply that EGOT may be a novel therapeutic target for HCC, and highlights the key role of EGOT/miR-33a-5p/HMGA2 in the progression of this deadly disease.

LncRNA CACS15 regulates tongue squamous cell carcinoma cell behaviors and predicts survival

BACKGROUND

The involvement of lncRNA CASC15 in several types of cancers has been reported, while its role in tongue squamous cell carcinoma (TSCC) is unknown. Our study aimed to investigate the clinical potentials of lncRNA CASC15 in TSCC.

METHODS

The expression of CASC15 and miR-124 in tissue samples from TSCC patients and TSCC cell lines was analyzed by qPCR. Overexpression experiments were performed to analyze the interactions between CASC15 and miR-124. Survival analysis was performed to analyze the prognostic values of CASC15 and miR-124 for TSCC. Transwell assays were performed to analyze cell invasion and migration.

RESULTS

We found that CASC15 was upregulated, while miR-124 was downregulated in TSCC tissues than in non-cancer tissues of TSCC patients. CASC15 and miR-125 expression was not significantly different among patients with different clinical stages, and patients with high level of CASC15 and low level of miR-125 showed low overall survival rate. CASC15 and miR-124 were inversely correlated in TSCC tissues, and CASC15 overexpression in TSCC cells resulted in downregulation of miR-124. In contrast, overexpression of miR-124 showed no significant effect on CASC15 expression. CASC15 overexpression resulted in the increased, while miR-124 overexpression resulted in the decreased migration and invasion rates of TSCC cells.

CONCLUSION

CASC15 and miR-124 predict TSCC patients' survival and CASC15 may downregulate miR-124 to inhibit TSCC cell migration and invasion. The study was approved by Ethics Committee of The first Affiliated Hospital of Jinzhou Medical University (20103548FAHJMU).

LncRNA CASC15 Functions As An Unfavorable Predictor Of Ovarian Cancer Prognosis And Inhibits Tumor Progression Through Regulation Of miR-221/ARID1A Axis

Background

LncRNA cancer susceptibility candidate 15 (CASC15) has been demonstrated to act as an oncogene in different cancers; however, its role in ovarian cancer remains elusive.

Methods

Quantitative real-time PCR (qRT-PCR) was performed to examine the expression of lncRNA CASC15. Kaplan–Meier survival analysis was performed to evaluate the prognostic significance of lncRNA CASC15. CCK-8, soft-agar colony-formation, flow cytometry, transwell migration and invasion assays were used to analyze the biological behavior of lncRNA CASC5 in ovarian cancer. Furthermore, the potential mechanism of lncRNA CAC15 was investigated by bioinformatics analysis, luciferase reporter assay, and biotin pull-down assay.

Results

In this study, we found that the expression of CASC15 was lower in ovarian cancer tissues and cells by qRT-PCR. In addition, low expression of CASC15 was closely correlated with advanced TNM stage, moderate/poor differentiation, and larger size. Moreover, Kaplan–Meier survival analysis showed that patients with low CASC15 expression level had poorer overall survival and progression-free survival than those with high CASC15 expression. Meanwhile, ROC analysis found that CASC15 had diagnostic values to distinguish tumor tissues from nontumorous tissues. Overexpression of CASC15 prohibited the malignancy of ovarian cancer cells, including proliferation, colony formation, cell cycle, migration, and invasion, and promoted cell apoptosis. In addition, bioinformatics analysis, luciferase reporter assay, and biotin pull-down assay confirmed that CASC15 straightly interacted with miR-221. We also observed that ARID1A was a downstream target of miR-221 and CASC15 subsequently exerted its tumor-suppressive effects by regulating the expression of ARID1A in ovarian cancer cells.

Conclusion

Overall, this study firstly elucidated that CASC15 could play a tumor-suppressive role in ovarian cancer by the regulation of CASC15/miR-221/ARID1A axis, which may provide a ponderable prognostic biomarker and promising therapeutic target for treatment of patients with ovarian cancer.

MicroRNA-33a-5p suppresses esophageal squamous cell carcinoma progression via regulation of lncRNA DANCR and ZEB1

Increasing evidence displays that microRNAs (miRNAs) participate in the development of various human malignancies, including esophageal squamous cell carcinoma (ESCC). MicroRNA-33a-5p (miR-33a-5p) has recently been reported to function as a tumor suppressor in many human cancers. However, the expression and role of miR-33a-5p in ESCC remains largely unknown. Herein, we discovered that miR-33a-5p was down-regulated in both ESCC tissues and cell lines, compared with their normal counterparts, and decreased expression of miR-33a-5p was found to be closely associated with poor patient prognosis of ESCC. Moreover, functional experiments revealed that up-regulation of miR-33a-5p inhibited cell proliferation and metastasis of ESCC cells. In addition, the expression level of miR-33a-5p was found to be negatively correlated with the long non-coding RNA (lncRNA) differentiation antagonizing non-protein coding RNA (DANCR), in both ESCC tissues and cell lines. Furthermore, zinc-finger-enhancer binding protein 1 (ZEB1) was predicted and confirmed to be a direct target of miR-33a-5p in ESCC. Further mechanistic investigation indicated that DANCR may function as a competing endogenous RNA (ceRNA) to sponge miR-33a-5p, and thereby up-regulate ZEB1 expression in ESCC. This study highlights the functions of miR-33a-5p in the progression of ESCC and suggests that the DANCR/miR-33a-5p/ZEB1 axis may be a potential prognostic and therapeutic target.