Silencing of long non-coding RNA CCAT2 depressed malignancy of oral squamous cell carcinoma via Wnt/β-catenin pathway

Indole-3-Carbinol Promotes Apoptosis and Inhibits the Metastasis of Esophageal Squamous Cell Carcinoma by Downregulating the Wnt/β-Catenin Signaling Pathway

The incidence and mortality rates of esophageal squamous cell carcinoma (ESCC) have been significantly increasing in China. Indole-3-carbinol (I3C), a naturally occurring component in cruciferous vegetables, is an effective cancer therapy. Yet, its effect and action mechanism in ESCC are still not fully understood. This study explored the role of I3C in ESCC in vitro and in vivo by focusing on the Wnt/β-catenin signaling pathway. MTT and flow cytometry were used to assess cell viability and apoptosis in EC18 and TE1 cells, while wound healing and transwell assays were used to investigate cell migration and invasion in vitro. Expression of β-catenin, c-myc, and cyclin D1 was determined by Western blot; LiCl (an agonist of the canonical Wnt signaling that inhibits GSK3β activity) was used to assess the role of I3C on the Wnt/β-catenin signaling pathway. For in vivo experiments, nude BALB/c mice bearing EC18 xenografts were treated with I3C and/or LiCl. I3C promoted ESCC apoptosis and inhibited cell migration and invasion by downregulating β-catenin, c-myc, and cyclin D1 in vitro and decreased the tumor growth in vivo; this process was reversed by LiCl treatment. In summary, I3C inhibits ESCC malignant behavior by suppressing the Wnt/β-catenin signaling pathway, thus deeming it a promising drug for ESCC treatment.

lncRNA CCAT2 Protects Against Cardiomyocyte Injury After Myocardial Ischemia/Reperfusion by Regulating BMI1 Expression

Myocardial ischemia/reperfusion (I/R) decreases cardiac function and efficiency. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) have been linked to the cellular processes of myocardial I/R injury. The present investigation elucidated the function of lncRNA colon cancer-associated transcript 2 (CCAT2) in myocardial I/R injury and the related mechanisms.AC16 cardiomyocytes were exposed to hypoxia (16 hours) /reoxygenation (6 hours) (H/R) to mimic myocardial I/R models in vitro. CCAT2 and microRNA (miR) -539-3p expressions in AC16 cardiomyocytes were measured using real-time quantitative polymerase chain reaction. B-cell-specific Moloney murine leukemia virus insertion region 1 (BMI1) protein levels in AC16 cardiomyocytes were determined by western blotting. Cell viability, lactate dehydrogenase (LDH) leakage, reactive oxygen species (ROS) levels, mitochondrial membrane potential, and apoptosis were detected using Counting Kit-8, LDH Assay Kit, dihydroethidium assay, 5,5',6,6'-tetrachloro1,1',3,3'-tetramethylbenzimidazolylcarbocyanine iodide staining, flow cytometry, and western blotting, respectively. The interactions between the molecules were confirmed using the dual-luciferase gene reporter. The wingless/integrated/beta-catenin (Wnt/β-catenin) pathway under the H/R condition was detected by western blotting.CCAT2 and BMI1 mRNA expressions were reduced in H/R-exposed AC16 cardiomyocytes. CCAT2 overexpression exerted protective effects against H/R-induced cardiomyocyte injury, as demonstrated by increased cell viability and mitochondrial membrane potential and decreased LDH leakage, ROS levels, and apoptosis. In addition, CCAT2 positively regulated BMI1 expression by binding to miR-539-3p. CCAT2 knockdown or miR-539-3p overexpression restrained the protective effects of BMI1 against H/R-induced cardiomyocyte injury. In addition, miR-539-3p overexpression reversed the protective effects of CCAT2. Furthermore, CCAT2 activated the Wnt/β-catenin pathway under the H/R condition via the miR-539-3p/BMI1 axis.Overall, this investigation showed the protective effects of the CCAT2/miR-539-3p/BMI1/Wnt/β-catenin regulatory axis against cardiomyocyte injury induced by H/R.

Knockdown of Long Noncoding RNA CCAT2 Suppresses Malignant Phenotype in Human Laryngeal Squamous Cell Carcinoma

This study aimed to explore the biological role and mechanism underlying the effects of colon cancer-associated transcript 2 (CCAT2), a long noncoding RNA (lncRNA) in human laryngeal squamous cell carcinoma (LSCC). CCAT2 expression levels in clinical LSCC samples and TU-212 cell line were evaluated by quantitative real-time PCR. The correlation of CCAT2 expression level with clinical-pathological characteristics of patients and their prognosis was analyzed. The functional role of CCAT2 in human LSCC was assessed by Cell Counting Kit-8, Transwell assay, flow cytometric analysis, and LSCC xenograft experiment in vivo. The expression of potential targeted proteins was detected by Western blotting and immunohistochemistry. We found that expression of CCAT2 was significantly elevated in LSCC tissues and TU-212 cells (p<0.05). Survival analysis showed that LSCC patients with high expression of CCAT2 had a shorter 5-year overall survival rate than those with low expression (p<0.05). In addition, CCAT2 silencing with short hairpin RNA significantly decreased the proliferative and invasive potential of TU-212 cells (p<0.05) and promoted their apoptosis. In Nude mice, CCAT2 knockdown suppressed the growth of tumor and decreased its volume and weight in comparison with the controls (p<0.05). In TU-212 cells, CCAT2 silencing with short hairpin RNA significantly down-regulated the expression of β-catenin and CDK8 (p<0.05). Thus, knockdown of CCAT2 suppresses proliferation and invasion of the cells and inhibits Wnt/β-catenin signaling pathway in LSCC, which indicates novel therapeutic targets and prognostic indicators in patients with LSCC.

Noncoding RNAs in oral cancer

Oral cancer (OC) is the most prevalent subtype of cancer arising in the head and neck region. OC risk is mainly attributed to behavioral risk factors such as exposure to tobacco and excessive alcohol consumption, and a lesser extent to viral infections such as human papillomaviruses and Epstein-Barr viruses. In addition to these acquired risk factors, heritable genetic factors have shown to be associated with OC risk. Despite the high incidence, biomarkers for OC diagnosis are lacking and consequently, patients are often diagnosed in advanced stages. This delay in diagnosis is reflected by poor overall outcomes of OC patients, where 5-year overall survival is around 50%. Among the biomarkers proposed for cancer detection, noncoding RNA (ncRNA) can be considered as one of the most promising categories of biomarkers due to their role in virtually all cellular processes. Similar to other cancer types, changes in expressions of ncRNAs have been reported in OC and a number of ncRNAs have diagnostic, prognostic, and therapeutic potential. Moreover, some ncRNAs are capable of regulating gene expression by various mechanisms. Therefore, elucidating the current literature on the four main types of ncRNAs namely, microRNA, lncRNA, snoRNA, piwi-RNA, and circular RNA in the context of OC pathogenesis is timely and would enable further improvements and innovations in diagnosis, prognosis, and treatment of OC. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Long non-coding RNA colon cancer-associated transcript 2: role and function in human cancers

ABSTRACT

Long non-coding RNAs (lncRNAs) are a family of non-protein-coding RNAs that span a length of over 200 nucleotides. Research reports have illustrated that lncRNAs are involved in various cellular processes and that their abnormal expression leads to the occurrence and development of various tumors. Colon cancer-associated transcript 2 (CCAT2) was first reported as an oncogene in colon cancer. LncRNA CCAT2 is abnormally expressed in hepatocellular carcinoma, cholangiocarcinoma, lung cancer, breast cancer, ovarian cancer, glioma, and other tumors. In tumor tissues, abnormally overexpressed CCAT2 can affect cell proliferation, migration, epithelial-mesenchymal transition, apoptosis, and other biological behaviors through endogenous RNAs mechanisms, various signaling pathways, transcriptional regulation, and other complex mechanisms. Additionally, the overexpression of CCAT2 is also closely related to the tumor size, tumor node metastasis (TNM) stage, survival time, and other prognostic factors, suggesting that it is a potential prognostic indicator. This article reviews the biological functions of CCAT2 and its mechanisms of action in tumors from previous studies. In this review, we attempt to provide a molecular basis for future clinical applications of lncRNA CCAT2.

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.

Identification of Differentially Expressed Long Noncoding RNAs as Functional Biomarkers and Construction of Function Enrichment Network in Oral Squamous Cell Carcinoma

Objective

This study aims to find the novel lncRNAs closely related to the progression of oral squamous cell carcinoma (OSCC) by comprehensively analyzing microarray.

Methods

Chip dataset GSE84805 was downloaded from the Gene Expression Omnibus (GEO) database, lncRNA expression profiles of OSCC and paracancerous tissue were obtained, probes sequences reannotation was conducted, and differentially expressed lncRNAs (DELs) and differentially expressed genes (DEGs) were identified. Finally, these data were analyzed by constructing the lncRNA-function enrichment network.

Results

We found that 465 lncRNAs are differentially expressed consisting of 193 upregulated lncRNAs and 272 downregulated lncRNAs. Meanwhile, 811 DEGs were identified with 498 upregulated genes and 313 downregulated genes. Analysis of the lncRNA-function enrichment network showed that these aberrant lncRNAs may be related to focal adhesion, inflammatory response pathway, cell cycle, matrix metalloproteinases, and other biological functions. Also, we found that some key lncRNAs such as LINC00152 and HOXA11-AS have been shown to play an important role in tumor proliferation and migration.

Conclusion

The key lncRNAs may serve as potential molecular markers or therapeutic targets in OSCC formation and development. It can also help us to understand the molecular mechanism of occurrence and development in OSCC.

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.

The Roles of the Colon Cancer Associated Transcript 2 (CCAT2) Long Non-Coding RNA in Cancer: A Comprehensive Characterization of the Tumorigenic and Molecular Functions

Colon cancer-associated transcript 2 (CCAT2) is an intensively studied lncRNA with important regulatory roles in cancer. As such, cumulative studies indicate that CCAT2 displays a high functional versatility due to its direct interaction with multiple RNA binding proteins, transcription factors, and other species of non-coding RNA, especially microRNA. The definitory mechanisms of CCAT2 are its role as a regulator of the TCF7L2 transcription factor, enhancer of MYC expression, and activator of the WNT/β-catenin pathway, as well as a role in promoting and maintaining chromosome instability through the BOP1–AURKB pathway. Additionally, we highlight how the encompassing rs6983267 SNP has been shown to confer CCAT2 with allele-specific functional and structural particularities, such as the allelic-specific reprogramming of glutamine metabolism. Additionally, we emphasize CCAT2’s role as a competitive endogenous RNA (ceRNA) for multiple tumor suppressor miRNAs, such as miR-4496, miR-493, miR-424, miR-216b, miR-23b, miR-34a, miR-145, miR-200b, and miR-143 and the pro-tumorigenic role of the altered regulatory axis. Additionally, due to its upregulation in tumor tissues, wide distribution across cancer types, and presence in serum samples, we outline CCAT2’s potential as a biomarker and disease indicator and its implications for the development of resistance against current cancer therapy regiments and metastasis.

Assessment of multiple pathways involved in the inhibitory effect of HCG22 on oral squamous cell carcinoma progression

LncRNAs have been proposed to be associated with the tumorigenesis and progression of oral squamous cell carcinoma (OSCC). LncRNA HLA complex group 22 (HCG22) was reported to be lowly expressed and associated with poor prognosis in head and neck squamous cell carcinoma (HNSCC). However, the biological role and related mechanism of HCG22 in OSCC have not been characterized. HCG22 expression in OSCC cells was detected by qRT-PCR. Cell proliferation, invasion, and apoptosis were evaluated by Bromodeoxyuridine (BrdU) proliferation assay, Transwell invasion assay, and flow cytometry analysis, respectively. The protein levels of proliferating cell nuclear antigen (PCNA), E-cadherin, Vimentin, Bcl-2, Bax, protein kinase B (Akt), phosphorylated Akt (p-Akt), mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), and β-catenin were detected by western blot. Cell growth evaluation was performed using in vitro colony formation assay and in vivo tumor xenograft assay. We found that HCG22 was weakly expressed in OSCC cells. HCG22 overexpression inhibited cell proliferation and invasion and induced apoptosis in OSCC cells. The levels of PCNA, Vimentin, and Bcl-2 were decreased and E-cadherin and Bax expression was elevated in OSCC cells after HCG22 overexpression. Additionally, HCG22 overexpression inhibited the Akt, mTOR and Wnt/β-catenin pathways. Activation of Akt, mTOR, and Wnt/β-catenin pathways attenuated the anti-tumor property of HCG22 in OSCC cells. Furthermore, HCG22 overexpression inhibited the growth of OSCC cells in vitro and in vivo. In conclusion, HCG22 exerted anti-tumor property in OSCC by inhibiting the Akt, mTOR, and Wnt/β-catenin pathways.

The roles of extracellular vesicles in the development, microenvironment, anticancer drug resistance, and therapy of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the main malignant tumours affecting human health, mainly due to delayed diagnosis and high invasiveness. Extracellular vehicles (EVs) are membranous vesicles released by cells into the extracellular matrix that carry important signalling molecules and stably and widely exist in various body fluids, such as plasma, saliva, cerebrospinal fluid, breast milk, urine, semen, lymphatic fluid, synovial fluid, amniotic fluid, and sputum. EVs transport almost all types of bioactive molecules (DNA, mRNAs, microRNAs (miRNAs), proteins, metabolites, and even pharmacological compounds). These "cargoes" can act on recipient cells, reshaping the surrounding microenvironment and altering distant targets, ultimately affecting their biological behaviour. The extensive exploration of EVs has deepened our comprehensive understanding of HNSCC biology. In this review, we not only summarized the effect of HNSCC-derived EVs on the tumour microenvironment but also described the role of microenvironment-derived EVs in HNSCC and discussed how the "mutual dialogue" between the tumour and microenvironment mediates the growth, metastasis, angiogenesis, immune escape, and drug resistance of tumours. Finally, the clinical application of EVS in HNSCC was assessed.

Knockdown of long non‑coding RNA CCAT2 suppresses the progression of thyroid cancer by inhibiting the Wnt/β‑catenin pathway

Thyroid cancer (TC) is one of the most common malignancies with a high mortality rate. Long non-coding RNA CCAT2 (CCAT2) participates in the occurrence and development of certain human cancers; however, whether it is involved in TC remains unclear. Thus, the present study investigated the role of CCAT2 in TC and the underlying mechanism. CCAT2 expression in both TC tissues and cell lines was examined by reverse transcription-quantitative PCR. CCAT2 expression was silenced in TC cell lines by a specific small interfering (si)RNA against CCAT2 (si-CCAT2). The effects of CCAT2 silencing on TC cell proliferation were detected by CCK-8 and colony formation assays. Cell cycle and apoptosis of the treated TC cells were assessed by flow cytometry. Wound healing and Transwell assays were performed to detect the effects of si-CCAT2 on the migration and invasion of TC cells. Apoptosis-related proteins and Wnt/β-catenin cascade-associated agents were examined by western blotting. The interaction between CCAT2 and the Wnt/β-catenin pathway in the transfected cells was detected by performing a dual-luciferase reporter assay. CCAT2 expression was increased in TC tissue samples and cell lines compared with the controls. Tissue CCAT2 level was associated with T stage and tumor-node-metastasis stage of TC. Silencing CCAT2 inhibited TC cell proliferation, migration and invasion, and promoted TC cell cycle arrest and apoptosis. Furthermore, CCAT2 knockdown suppressed the activity of the Wnt/β-catenin cascade in TC cells treated with lithium chloride. In summary, the present study demonstrated that CCAT2 knockdown suppresses TC progression via inactivating the Wnt/β-catenin cascade, indicating that suppressing CCAT2 and the Wnt/β-catenin signaling pathway may be a promising therapeutic strategy for treating TC.

Long noncoding RNAs in head and neck squamous cell carcinoma: biological functions and mechanisms

Head and neck squamous cell carcinoma (HNSCC) is the primary malignant tumor of the oral cavity, larynx, nasopharynx, esophagus and tongue. Although several novel therapeutic methods for HNSCC have been developed, the final therapeutic effect on the patient is still not satisfactory. Thus, it is imperative that scientists identify novel distinguishable markers with specific molecular characteristics that can be used in therapeutic and prognostic evaluation. Previous reports have shown that long noncoding RNAs (lncRNAs) are important regulators of gene expression in many cancers, including head and neck squamous cell carcinomas. Translational studies of lncRNAs in HNSCC are urgently required before their application as a treatment can be realized. We aimed to address the most relevant findings on lncRNAs as biomarkers or treatment targets in head and neck squamous cell carcinoma and to summarize their discovered pathways and mechanisms of action to reveal the possible future applications of these novel biomarkers in clinical translational research.

Long non-coding RNA CCAT2 promotes prostate cancer cell proliferation and invasion by regulating the Wnt/β-catenin signaling pathway

Long non-coding RNA colon cancer associated transcript 2 (CCAT2) is dysregulated in a number of different types of human cancer, and affects cancer progression via the Wnt/β-catenin signaling pathway. However, the roles of CCAT2 and the Wnt/β-catenin signaling pathway in prostate cancer (PCa) are not completely understood. The present study aimed to investigate the potential mechanism of CCAT2 in PCa. In the present study, the reverse transcription-quantitative PCR (RT-qPCR) results indicated that CCAT2 expression was significantly upregulated in PCa tissues, and DU145 and PC3 cell lines compared with normal prostate tissues and the epithelial RWPE-1 cell line, respectively. Functional assays indicated that CCAT2 downregulation inhibited DU145 and PC3 cell proliferation, cell cycle, migration and invasion. In addition, the luciferase reporter assay, RT-qPCR and western blotting results indicated that CCAT2 regulated transcription factor 7 like 2 (TCF7L2) expression by binding to microRNA-217. Further western blotting and TOPFlash assays indicated that CCAT2-knockdown inhibited the Wnt/β-catenin signaling pathway in DU145 and PC3 cell lines by inhibiting the expression of TCF7L2. However, CCAT2-knockdown-mediated effects were reversed by the Wnt/β-catenin signaling pathway activator lithium chloride (LiCl). Further cell experiments suggested that LiCl treatment reversed CCAT2-knockdown-mediated inhibition of PCa cell proliferation, cell cycle, epithelial-mesenchymal transition, migration and invasion. Overall, the results indicated that CCAT2 regulated PCa via the Wnt/β-catenin signaling pathway; therefore, CCAT2 may exhibit key role during the progression of PCa and may serve as a therapeutic target for the disease.

A Comprehensive Exploration of the lncRNA CCAT2: A Pan-Cancer Analysis Based on 33 Cancer Types and 13285 Cases

Whether the lncRNA CCAT2 expression level affects the clinical progression and outcome of cancer patients has not yet been fully elucidated. There is still an inconsistent view regarding the correlation between CCAT2 expression and clinicopathological factors, including survival data. Besides, the regulation mechanism of CCAT2 in human cancer is still unclear. Our study analyzed a large number of publication data and TCGA databases to identify the association of CCAT2 expression with clinicopathological factors and to explore the regulatory mechanisms in human cancers. We designed a comprehensive study to determine the expression of CCAT2 in human cancer by designing a meta-analysis of 20 selected studies and the TCGA database, using StataSE 12.0 to explore the relationship between CCAT2 expression and both the prognosis and clinicopathological features of 33 cancer types and 13285 tumor patients. Moreover, we performed GO and KEGG pathway enrichment analyses on potential target genes of CCAT2 collected from GEPIA and LncRNA2Target V2.0. The level of CCAT2 expression in tumor tissues is higher than that in paired normal tissues and is significantly associated with a poor prognosis in cancer patients. Besides, overexpression of CCAT2 was significantly associated with tumor size, clinical stage, and TNM classification. Meanwhile, CCAT2 expression is the highest in stage II of human cancer, followed by stage III. Finally, 111 validated target gene symbols were identified, and GO and KEGG demonstrated that the CCAT2 validation target was significantly enriched in several pathways, including microRNAs in the cancer pathway. In summary, CCAT2 can be a potential biomarker associated with the progression and prognosis of human cancer.

World Workshop on Oral Medicine VII: Functional pathways involving differentially expressed lncRNAs in oral squamous cell carcinoma

Long non-coding RNAs (lncRNA) modulate gene expression at the epigenetic, transcriptional and post-transcriptional levels and are involved in tumorigenesis. They can form complex secondary and tertiary structures and have been shown to act as precursors, enhancers, reservoirs and decoys in the complex endogenous RNA network. They were first reported in relation to oral squamous cell carcinoma (OSCC) in 2013. Here, we summarise the functional roles and pathways of the most commonly studied lncRNAs in OSCC. Existing research demonstrates the involvement of lncRNA within pivotal pathways leading to the development and spread of OSCC, including interactions with key cancer-associated microRNAs such as miR-21. The number of studies on lncRNA and OSCC remains limited in this new field. As evidence grows, the tissue-specific expression patterns of lncRNAs should further advance our understanding of the altered regulatory networks in OSCC and possibly reveal new biomarkers and therapeutic targets.

LncRNA AC007271.3 promotes cell proliferation, invasion, migration and inhibits cell apoptosis of OSCC via the Wnt/β-catenin signaling pathway

AIMS

Long noncoding RNA (lncRNA) AC007271.3 has been identified to be dysregulated in oral squamous cell carcinoma (OSCC) in our previous study. However, the precise role of AC007271.3 in OSCC remains unclear. In this study, we investigated the potential functions and the underlying mechanisms of AC007271.3 in OSCC.

MATERIALS AND METHODS

The expression levels of AC007271.3 in OSCC tissues and cell lines were examined using RT-qPCR. The relationship between AC007271.3 level and clinicopathological characteristics was analyzed, and its association with patient prognosis was assessed by the Kaplan-Meier method. The biological function of AC007271.3 and its role in the development of OSCC through Wnt/β-catenin signaling pathway were studied.

KEY FINDINGS

We identified that AC007271.3 was up-regulated and positively correlated with advanced clinical stage, lymph node metastasis, poor histological differentiation and unfavorable prognosis. We explored the expression, function, and molecular mechanism of AC007271.3 in OSCC cells. Overexpression of AC007271.3 remarkably promoted cell proliferation in vitro and in vivo, induced cell migration, invasion and inhibited apoptosis in vitro, while knockdown of AC007271.3 attenuated cell proliferation, migration, invasion and induced apoptosis. Mechanistically, AC007271.3 overexpression substantially increased the expression of β-catenin and the downstream target molecules CyclinD1, c-myc and Bcl-2, while silencing of AC007271.3 has the opposite effect. Rescued experiments showed that the ability to promote cell proliferation, migration, invasion and inhibiting apoptosis could be reversed when treated with the Wnt/β-catenin pathway inhibitor.

SIGNIFICANCE

Our data indicated that AC007271.3 could promote cell proliferation, invasion and inhibit cell apoptosis of OSCC via the Wnt/β-catenin signaling pathway, which might provide a novel therapeutic approach for OSCC.

Colon Cancer-Associated Transcripts 1 and 2: Roles and functions in human cancers

The long noncoding RNAs (lncRNAs) Colon Cancer-Associated Transcripts 1 and 2 (CCAT1 and CCAT2) are located in a recurrently amplified region in cancers. Their proximity with the Myc oncogene and their interactions with its promoter provided further evidence for their contribution in the tumorigenesis processes. Several cell line and clinical studies have shown upregulation of these lncRNAs in diverse malignancies. Moreover, some single nucleotide variants within these genes have been associated with cancer risk or therapeutic response in different populations. Besides, these two lncRNAs act as sponges for some tumor suppressor microRNAs (miRNAs), thus promoting cancer evolution. In the current study, we review recent literature about their expression level, interaction with cancer-related pathways, their role in determination of cell fate and their contribution in malignant phenotype characteristics. Taken together, the current literature shows that these lncRNAs are putative targets for design of novel treatment strategies. Moreover, their expression levels in biopsied samples, exosomes, and sera of patients might be applied as diagnostic biomarkers or markers for patient follow-up.

Long non-coding RNA colon cancer-associated transcript 2 may promote esophageal cancer growth and metastasis by regulating the Wnt signaling pathway

The aim of this study was to investigate how long non-coding (lnc)RNA colon cancer-associated transcript 2 (CCAT2) regulates the proliferation, invasion and metastasis of esophageal cancer cells via the Wnt signaling pathway. The expression of lncRNA CCAT2 was quantified by reverse transcription-quantitative PCR in four esophageal cancer cell lines (Eca-109, EC9706, KYSE150 and TE-1) and normal human esophageal epithelial cells (HEECs). The effect of silencing CCAT2 (si-CCAT2) and inhibiting Wnt signaling (using the inhibitor FH535) on the proliferation, migration and invasion of Eca-109 cells was measured by MTT, wound-healing and Transwell invasion assays. Flow cytometry was used to evaluate apoptosis in si-CCAT2 Eca-109 cells. The expression of β-catenin and proliferating cell nuclear antigen (PCNA) proteins was detected by immunohistochemistry. The pro-apoptotic protein Bax, cyclin D1 and Wnt target proteins, including c-Myc and adenomatous polyposis coli (APC), were detected by western blotting. LncRNA CCAT2 was highly expressed in the four esophageal cancer cell lines compared with the HEEC cells. The expression of CCAT2 was significantly decreased in si-CCAT2 Eca-109 cells. Treatment with si-CCAT2 and FH535 alone or in combination significantly inhibited the proliferation, migration and invasion of Eca-109 cells. The treatments also promoted apoptosis, upregulated the expression of Bax and APC proteins, and downregulated β-catenin, PCNA, cyclin D1 and c-Myc proteins. In summary, lncRNA CCAT2 is upregulated in esophageal cancer cells and the knockdown of lncRNA CCAT2 inhibits their proliferation, migration and invasion via the Wnt signaling pathway.

World Workshop on Oral Medicine VII: Clinical evidence of differential expression of lncRNAs in oral squamous cell carcinoma: A scoping review

BACKGROUND

Long non-coding RNAs (lncRNAs) have important roles in regulating gene expression pertaining to cell proliferation, survival, migration and genomic stability. Dysregulated expression of lncRNAs is implicated in cancer initiation, progression and metastasis.

OBJECTIVES

To explore, map and summarize the extent of evidence from clinical studies investigating the differential expression of lncRNAs in oral/tongue squamous cell carcinoma.

METHODS

PubMed, Scopus and Web of Science were used as search engines. Clinical, full-length, English language studies were included. PRISMA-ScR protocol was used to evaluate and present results. The present scoping review summarizes relationships of the differential expression of lncRNAs with the presence of tumour and with clinicopathological features including survival.

RESULTS

Almost half of the investigated transcripts have been explored in more than one study, yet not always with consistent results. The collected data were also compared to the limited studies investigating oral epithelial dysplasia. Data are not easily comparable, first because of different methods used to define what differential expression is, and second because only a limited number of studies performed multivariate analyses to identify clinicopathological features associated with the differentially expressed lncRNAs.

CONCLUSIONS

Standard methods and more appropriate data analyses are needed in order to achieve reliable results from future studies.

Upregulated long noncoding RNA ENST00000470447.1 inhibits cell migration and invasion and predicts better disease-free survival of oral cancer

BACKGROUND

The aim of the present study was to assess the long noncoding RNA (lncRNA) expression profile of oral cancer and clarify the biological functions and clinical value of a novel lncRNA ENST00000470447.1.

METHOD

Microarray assay was used to explore lncRNA expression profiles in three paired oral cancer and adjacent normal tissue samples. The expression of targeted lncRNA (ENST00000545372.1, ENST00000470447.1, and ENST00000412353.1) was validated by quantitative real-time polymerase chain reaction. Then we evaluated the biological and clinical roles of ENST00000470447.1 in oral cancer by in vitro assays and multivariable Cox regression analysis.

RESULTS

LncRNAs were aberrantly expressed in oral cancer tissues. The expression levels of ENST00000470447.1 and ENST00000412353.1 in oral cancer tissues were significantly lower than those in matched adjacent noncancerous tissues (P < .001). in vitro assays indicated that overexpression of ENST00000470447.1 significantly inhibited the proliferation, migration, and invasion ability of Tca-8113 cells, whereas promoted the apoptosis of Tca-8113 cells. Furthermore, ENST00000470447.1 expression was significantly correlated with tumor differentiation (P = .030). Cox regression analyses demonstrated that high ENST00000470447.1 expression was associated with better disease-free survival for patients with oral cancer (hazard ratio: 0.25, 95% CI: 0.06-0.95; P = .041).

CONCLUSION

Our findings suggest that ENST00000470447.1 can be served as a potential novel marker for recurrence and metastasis prediction of patients with oral cancer, which may provide a potential therapeutic target for oral cancer.

Non-coding RNA NEAT1/miR-214-3p contribute to doxorubicin resistance of urothelial bladder cancer preliminary through the Wnt/β-catenin pathway

BACKGROUND

Urothelial bladder cancer (UBC) is one of the most lethal urological malignancies in the world. Patients with UBC are routinely given chemotherapy which results in a median survival of 12-15 months. Nuclear-enriched abundant transcript 1 (NEAT1) functions as an oncogene and could be used as a therapeutic target for human UBC. However, the involvement of NEAT1 in doxorubicin (DOX) resistance of UBC has been poorly demonstrated.

METHODS

Quantitative Real-time PCR (qRT-PCR) was used to detect the expression levels of NEAT1 and miR-214-3p in UBC tissues and cells. Bioinformatics prediction, RNA pull-down and qRT-PCR were used to assay the regulation manner of NEAT1 and miR-214-3p. Loss/gain function of NEAT1 and miR-214-3p together with western blot, drug resistance assay and flow cytometry were used to explore the influence of NEAT1 in DOX resistance was correlative with miR-214-3p. Finally, luciferase assay system was applied to determine the Wnt/β-catenin signal activity.

RESULTS

NEAT1 was upregulated and miR-214-3p was downregulated in DOX-resistant UBC tissues and cells. NEAT1 knockdown inhibited J82 and T24 cells to DOX chemosensitivity by negatively regulating miR-214-3p expression. NEAT1/miR-214-3p contributed to DOX resistance of UBC preliminary through the Wnt/β-catenin pathway.

CONCLUSION

NEAT1 contributed to DOX resistance of UBC through the Wnt/β-catenin pathway partly by negatively regulating miR-214-3p expression. Our findings will provide a promising ncRNA targeted therapeutic strategy for UBC with DOX resistance.

Long non-coding RNA-CCAT2 promotes the occurrence of non-small cell lung cancer by regulating the Wnt/β-catenin signaling pathway

The present study aimed to investigate the biological function of colon cancer-associated transcript 2 (CCAT2) in the occurrence and progression of non-small cell lung carcinoma (NSCLC) and its potential use in the early diagnosis and molecular-targeted therapy of NSCLC. The tumor tissues, para-carcinoma tissues and associated clinical data of 36 patients with NSCLC were collected in order to detect the expression of CCAT2 and assess the impact of factors including histopathological type, Tumor-Node-Metastasis stage and lymph node metastasis on CCAT2 expression. The lung cancer NCI-H1975 cell line was transfected with a small interfering RNA (siRNA) plasmid to determine the effect of si-CCAT2 on NSCLC proliferation, invasion and metastasis. The effect of si-CCAT2 on the expression of nuclear and cytoplasmic β-catenin protein in the lung cancer NCI-H1975 cell line was detected using western blot analysis. The expression levels of CCAT2 in the tumor tissues of patients with NSCLC were significantly higher than those in the normal para-carcinoma tissues (t=8.580, P<0.01). Subsequent to CCAT2 silencing, the proliferation and invasive abilities of NCI-H1975 cells were significantly decreased compared with control cells (P<0.05). In the si-CCAT2 group, the level of nuclear and cytoplasmic β-catenin proteins was decreased, and the activity of the Wnt signaling pathway was significantly inhibited compared with the control cells (P<0.01), and a synergistic effect was exerted with the Wnt signaling inhibitor FH535. CCAT2 may therefore promote the occurrence of NSCLC by regulating the Wnt/β-catenin signaling pathway.

Long non-coding RNA CDKN2B antisense RNA 1 gene inhibits Gemcitabine sensitivity in bladder urothelial carcinoma

Objective: To investigate the clinical significance of long noncoding RNA (lncRNA) CDKN2B antisense RNA 1 (CDKN2B-AS) gene and its effects on Gemcitabine sensitivity in BUC.

Materials and Methods: The expression of CDKN2B-AS gene was examined with real-time quantitative PCR. The cell proliferation and the half maximal inhibitory concentration (IC50) of Gemcitabine were detected with enhanced CCK-8 assay. The apoptosis rate was examined using Annexin V-FITC/PI double-staining apoptosis kit. The protein expression was examined with western blotting. The activity of Wnt signaling pathway was examined with TOP/FOP luciferase assay.

Results: CDKN2B-AS gene was high-expressed in BUC tissues and J82, T24 cells compared with paracancerous normal urothelial tissues and SV-HUC-1 cells. Furthermore, the high-expression of CDKN2B-AS gene was related with high pathological grade and low Gemcitabine sensitivity of BUC tissues. The expression of CDKN2B-AS gene in Gemcitabine-resistant T24/Gem cells was much higher than that in T24 cells. Knockdown of CDKN2B-AS gene sensitized T24/Gem cells to Gemcitabine, promoted Gemcitabine-induced cytotoxicity. Knockdown of CDKN2B-AS gene inactivated Wnt signaling pathway, and Wnt signaling pathway mediated the effects on Gemcitabine sensitivity induced by CDKN2B-AS knockdown in T24/Gem cells.

Conclusion: LncRNA CDKN2B-AS is high-expressed in BUC and related to low Gemcitabine sensitivity of BUC. CDKN2B-AS inhibited Gemcitabine sensitivity through Wnt signaling pathway in BUC.

Tumor-derived extracellular vesicles in angiogenesis

Angiogenesis is crucial for tumor growth and metastasis. Recent studies revealed that tumor cells promote angiogenesis by secreting extracellular vesicles, which can be captured by endothelial cells. These tumor-derived extracellular vesicles carry microRNAs, long non-coding RNAs, and proteins, which activate pro-angiogenic signaling in endothelial cells. In this review, we will summarize the roles of tumor-derived extracellular vesicles in angiogenesis and the underlying molecular mechanisms.

A Looking-Glass of Non-coding RNAs in oral cancer

Oral cancer is a multifactorial pathology and is characterized by the lack of efficient treatment and accurate diagnostic tools. This is mainly due the late diagnosis; therefore, reliable biomarkers for the timely detection of the disease and patient stratification are required. Non-coding RNAs (ncRNAs) are key elements in the physiological and pathological processes of various cancers, which is also reflected in oral cancer development and progression. A better understanding of their role could give a more thorough perspective on the future treatment options for this cancer type. This review offers a glimpse into the ncRNA involvement in oral cancer, which can help the medical community tap into the world of ncRNAs and lay the ground for more powerful diagnostic, prognostic and treatment tools for oral cancer that will ultimately help build a brighter future for these patients.

Knockdown of long non-coding RNA Taurine Up-Regulated 1 inhibited doxorubicin resistance of bladder urothelial carcinoma via Wnt/β-catenin pathway

In genitourinary system, bladder cancer (BC) is the most common and lethal malignant tumor, which most common type is bladder urothelial carcinoma (BUC). Long non-coding RNA (lncRNA) Taurine Up-Regulated 1 (TUG1) gene is high-expressed in several malignant tumors, including BC. In this study, over-expression of TUG1 was found in BUC tissues and cell line resistant to doxorubicin (Dox). Knockdown of TUG1 inhibited the Dox resistance and promoted the cytotoxicity induced by Dox in T24/Dox cells. TUG1 knockdown also depressed the Wnt/β-catenin pathway, and the activation the Wnt/β-catenin pathway partly reversed the inhibitory effects of TUG1 knockdown on Dox resistance in T24/Dox cells. In conclusion, up-regulation of lncRNA TUG1 was related with the poor response of BUC patients to Dox chemotherapy, knockdown of TUG1 inhibited the Dox resistance of BUC cells via Wnt/β-catenin pathway. These findings might assist in the discovery of novel potential diagnostic and therapeutic target for BUC, thereby improve the effects of clinical treatment in patients.