Long non-coding RNA H1 promotes cell proliferation and invasion by acting as a ceRNA of miR‑138 and releasing EZH2 in oral squamous cell carcinoma

MicroRNA-138 promotes the progression of multiple myeloma through targeting paired PAX5

BACKGROUND

Multiple myeloma cancer stem cells (MMSC) have been considered as the leading cause of multiple myeloma (MM) drug resistance and eventual relapse, microRNAs (miRNAs) collectively participate in the progression of MM. However, the pathogenesis of miR-138 in MMSC is still not fully understood.

OBJECTIVE

The intention of this study was to investigate the mechanism and role of miR-138 in multiple myeloma.

METHOD

Bone marrow samples and peripheral blood from patients and normal controls were collected. Use Magnet-based Cancer Stem Cell Isolation Kit to separate and extract MMSC. Real-time quantitative PCR (RT-qPCR) was carried out to determine mRNA level. Western blot was applied to detect protein levels. MTT and flow cytometry were conducted to examine the proliferation and apoptosis of MMSC. Finally, dual-luciferase reporter gene assays were performed to confirm that paired box 5 (PAX5) is a direct target for miR-138.

RESULTS

Compared with normal group, the expression of miR-138 in patients was significantly up-regulated, and the expression of miR-138 was in a negative correlation with PAX5. Additionally, downregulated miR-138 facilitated the apoptosis and inhibited the proliferation of MMSC in vitro and in vivo. Downregulated miR-138 moderated the expression of PAX5, Bcl-2, Bax, and Caspase-3. PAX5 was a direct target of miR-138.

CONCLUSION

Taken together, miR-138 plays a carcinogenic role in MM, and miR-138 adjusted the proliferation and apoptosis of MMSC by targeting PAX5. miR-138 has the probability of becoming a new medicinal target for the treatment of MM.

Exosomal long non-coding RNAs in glioblastoma

Glioblastoma multiforme (GBM) is the most prevalent primary tumor found in the central nervous system, accounting for 70% of all adult brain tumors. The median overall survival rate is one year post-diagnosis with treatment, and only four months without treatment. Current GBM diagnostic methods, such as magnetic resonance imaging (MRI), surgery, and brain biopsies, have limitations. These include difficulty distinguishing between tumor recurrence and post-surgical necrotic regions, and operative risks associated with obtaining histological samples through direct surgery or biopsies. Consequently, there is a need for rapid, inexpensive, and minimally invasive techniques for early diagnosis and improved subsequent treatment. Research has shown that tumor-derived exosomes containing various long non-coding RNAs (lncRNAs) play critical regulatory roles in immunomodulation, cancer metastasis, cancer development, and drug resistance in GBM. They regulate genes that enhance cancer growth and progression and alter the expression of several key signaling pathways. Due to the specificity and sensitivity of exosomal lncRNAs, they have the potential to be used as biomarkers for early diagnosis and prognosis, as well as to monitor a patient's response to chemotherapy for GBM. In this review, we discuss the role of exosomal lncRNAs in the pathogenesis of GBM and their potential clinical applications for early diagnosis.

A snapshot of miRNAs in oral squamous cell carcinoma: Difference between cancer cells and corresponding normal cells

Oral squamous cell carcinoma (OSCC) constitutes the most aggressive tumors of the oral cavity and is one of the leading causes of cancer mortality worldwide. Although recent clinical treatment strategies have improved the survival rate, the outcome of OSCC patients still remains dismal because of the lack of efficient diagnostic and treatment tools. As one of the main actors of OSCC scenario, microRNAs (miRNAs) are involved in triggering, progression and metastasis through the regulation of various cancer-related signaling pathways. Identification followed by precise study of the biology and mechanism of action of miRNAs will greatly help to provide valuable insights regarding OSCC development and can be considered as an anti-OSCC target. In the current review, we have provided a focused summary of the latest published papers on the role of miRNAs in apoptosis, cell cycle, proliferation, EMT and metastasis of OSCC as well as the role of long noncoding RNAs in the modulation of miRNAs in OSCC.

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.

Prognostic Role of Long Noncoding RNAs in Oral Squamous Cell Carcinoma: A Meta-Analysis

Long noncoding RNAs (lncRNAs) have emerged as critical regulators of tumor progression, and lncRNA expression levels could serve as a potential molecular biomarker for the prognosis and diagnosis of some cancers. However, the prognostic value of lncRNAs in oral squamous cell carcinoma (OSCC) remains unclear. Thus, a meta-analysis was conducted to explore the potential prognostic value of lncRNAs in OSCC. We systematically searched PubMed, EBSCO, Web of Science, and Elsevier from 2005 to 2021 to identify all published studies that reported the association between lncRNAs and prognosis in OSCC. Then, we used meta-analytic methods to identify the actual effect size of lncRNAs on cancer prognosis. The hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated to assess the strength of the association. The reliability of those results was then examined using measures of heterogeneity and testing for selective reporting biases. According to the inclusion and exclusion criteria, a total of 17 studies were eligible in our meta-analysis, involving 1384 Asian patients. The results identified a statistically significant association of high lncRNA expression with poor overall survival [adjusted pooled hazard ratio (AHR) = 1.52; 95% confidence interval (CI): [1.26–1.84], p ≤ 0.001]. The present meta-analysis demonstrated that lncRNA expression might be used as a predictive prognostic biomarker for Asian patients with 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.

LncRNA HOXA-AS2 Promotes Oral Squamous Cell Proliferation, Migration, and Invasion via Upregulating EZH2 as an Oncogene

Oral squamous cell carcinoma (OSCC) is one of the most common types of cancer worldwide. Accumulating evidence has shown that long noncoding RNAs (lncRNAs) serve important roles in the development of OSCC. The purpose of this study was to investigate the biological function and underlying regulatory mechanism of lncRNA homeobox A cluster antisense RNA2 (HOXA-AS2) in OSCC. RT-qPCR was performed to analyze the HOXA-AS2 expressions in human immortalized oral epithelial cell (HIOEC) line, human OSCC cell lines, and plasma. The expression of HOXA-AS2 and enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) in Tca-8113 cells were knocked down or overexpressed by transfection with shRNA-HOXA-AS2 or pcDNA-EZH2, respectively. The interaction between HOXA-AS2 and EZH2 was validated by RNA immunoprecipitation assay. In addition, cell proliferation was assessed by CCK-8 and EdU assays. Cell cycle distribution was analyzed by flow cytometry. Cell migration and invasion were detected using wound healing and Transwell assays, respectively. Apoptosis was detected by TUNEL staining. The protein expression levels of cell cycle and apoptosis-related proteins were measured by western blot analysis. Compared with HIOEC cells, HOXA-AS2 expression in OSCC cells was upregulated. HOXA-AS2 knockdown significantly inhibited Tca-8113 cell proliferation, blocked the cell cycle by arresting cells in the G0/G1 phase, promoted apoptosis, and suppressed migration and invasion. In addition, HOXA-AS2 was predicted to directly target EZH2 and positively regulate EZH2 expression. EZH2 overexpression could reverse the inhibitory effect of HOXA-AS2 knockdown on the proliferation, migration, and invasion of Tca-8113 cells. In summary, the findings suggested that HOXA-AS2 may inhibit cell proliferation, invasion, and migration, induce cell cycle arrest in the G0/G1 phase, and increase cell apoptosis by targeting EZH2. The research indicated that HOXA-AS2/EZH2 axis may play a key role in the development of OSCC.

Long Non-Coding RNAs as Functional Codes for Oral Cancer: Translational Potential, Progress and Promises

Oral cancer is one of the leading malignant tumors worldwide. Despite the advent of multidisciplinary approaches, the overall prognosis of patients with oral cancer is poor, mainly due to late diagnosis. There is an urgent need to develop valid biomarkers for early detection and effective therapies. Long non-coding RNAs (lncRNAs) are recognized as key elements of gene regulation, with pivotal roles in various physiological and pathological processes, including cancer. Over the past few years, an exponentially growing number of lncRNAs have been identified and linked to tumorigenesis and prognosis outcomes in oral cancer, illustrating their emerging roles in oral cancer progression and the associated signaling pathways. Herein, we aim to summarize the most recent advances made concerning oral cancer-associated lncRNA, and their expression, involvement, and potential clinical impact, reported to date, with a specific focus on the lncRNA-mediated molecular regulation in oncogenic signaling cascades and oral malignant progression, while exploring their potential, and challenges, for clinical applications as biomarkers or therapeutic targets for oral cancer.

Electroacupuncture promotes the recovery of rats with spinal cord injury by suppressing the Notch signaling pathway via the H19/EZH2 axis

Background

Spinal cord injury (SCI) is a life-changing event with an extremely poor prognosis. In our preliminary studies, electroacupuncture (EA) was found to promote the repair of SCI, which was closely related to the Notch signaling pathway. Therefore, in the present study, we hypothesized that EA protects against SCI by inhibiting the Notch signaling pathway and sought to investigate the underlying molecular mechanisms.

Methods

Rat and cell models of SCI were established. The expression of long non-coding RNA H19 was measured by real-time quantitative polymerase chain reaction. The expression levels of EZH2, Notch1, Notch3, Notch4, Hes1, and PS1 protein were measured by western blot. Cell apoptosis and viability were analyzed using flow cytometry and Cell Counting Kit-8 assays, respectively. The expressions of glial fibrillary acidic protein (GFAP) and nestin were detected by immunofluorescence staining.

Results

The expressions of H19, EZH2, and GFAP were significantly increased after SCI but were inhibited by EA; in contrast, nestin expression was significantly decreased by SCI but was restored by EA. Moreover, oxygen-glucose deprivation (OGD) treatment elevated the expression of H19, EZH2, and Notch-related factors as well as apoptosis in PC-12 cells, while suppressing cell viability. Suppressing H19 alleviated the effects of OGD on cell viability and apoptosis, and inhibited the expression of EZH2 and Notch-related factors expression; these effects were reversed by EZH2 overexpression. Finally, EA promoted the recovery of SCI rats and neural stem cell (NSC) proliferation by inhibiting the Notch signaling pathway, which was reversed by H19 overexpression.

Conclusions

Our results demonstrated that EA promotes the recovery of SCI rats and increases the proliferation and differentiation of NSCs by suppressing the Notch signaling pathway via modulating the H19/EZH2 axis.

Glycolysis reprogramming in cancer-associated fibroblasts promotes the growth of oral cancer through the lncRNA H19/miR-675-5p/PFKFB3 signaling pathway

As an important component of the tumor microenvironment, cancer-associated fibroblasts (CAFs) secrete energy metabolites to supply energy for tumor progression. Abnormal regulation of long noncoding RNAs (lncRNAs) is thought to contribute to glucose metabolism, but the role of lncRNAs in glycolysis in oral CAFs has not been systematically examined. In the present study, by using RNA sequencing and bioinformatics analysis, we analyzed the lncRNA/mRNA profiles of normal fibroblasts (NFs) derived from normal tissues and CAFs derived from patients with oral squamous cell carcinoma (OSCC). LncRNA H19 was identified as a key lncRNA in oral CAFs and was synchronously upregulated in both oral cancer cell lines and CAFs. Using small interfering RNA (siRNA) strategies, we determined that lncRNA H19 knockdown affected proliferation, migration, and glycolysis in oral CAFs. We found that knockdown of lncRNA H19 by siRNA suppressed the MAPK signaling pathway, 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and miR-675-5p. Furthermore, the lncRNA H19/miR-675-5p/PFKFB3 axis was involved in promoting the glycolysis pathway in oral CAFs, as demonstrated by a luciferase reporter system assay and treatment with a miRNA-specific inhibitor. Our study presents a new way to understand glucose metabolism in oral CAFs, theoretically providing a novel biomarker for OSCC molecular diagnosis and a new target for antitumor therapy.

Downregulation of long non-coding RNA LOC101928477 correlates with tumor progression by regulating the epithelial-mesenchymal transition in esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest malignancies. There is a growing body of evidence showing that long non‐coding RNAs (lncRNAs) play critical roles in ESCC oncogenesis. The present study aimed to explore the role of LOC101928477, a newly discovered lncRNA, in the development and metastasis of ESCC.

Methods

In this study, real‐time PCR, western blotting, cell counting kit‐8 (CCK‐8), flow cytometry, colony formation, wound healing, transwell migration/invasion assay, immunofluorescence, and immunohistochemistry were used. We also applied an in situ xenograft mouse model and a lung metastasis mouse model to verify our findings.

Results

We determined that LOC101928477 expression was inhibited in ESCC tissue and ESCC cell lines when compared with controls. Moreover, forced expression of LOC101928477 effectively inhibited ESCC cell proliferation, colony formation, migration, and invasion via suppression of epithelial‐mesenchymal transition (EMT). Furthermore, LOC101928477 overexpression inhibited in situ tumor growth and lung metastasis in a mouse model.

Conclusions

Together, our results suggested that LOC101928477 could be a novel suppressor gene involved in ESCC progression.

Down-Regulation of Long Non-Coding RNA TINCR Induces Cell Dedifferentiation and Predicts Progression in Oral Squamous Cell Carcinoma

Objectives

Recently long non-coding RNAs (lncRNAs) have emerged as novel gene regulators involved in tumorigenic processes, including oral squamous cell carcinoma (OSCC). Here, we identified a differentiation-related lncRNA, terminal differentiation-induced non-coding RNA (TINCR). However, its biological function and clinicopathological significance in OSCC still remain unclear.

Methods

The lncRNA expression profiles in OSCC tissues and paired adjacent non-tumor tissues (NATs) from 10 patients were detected by lncRNA microarrays. Weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) enrichment were performed to identify the most significant module and module functional annotation, respectively. Potential differentiation-related lncRNAs were screened by differential expression analysis. TINCR was further confirmed in OSCC cell lines and tissues of another patient cohort by using qRT-PCR. The correlation between the TINCR expression level and clinicopathological characteristics was analyzed. The effects of TINCR on cell differentiation, migration and invasion were assessed by knockdown or knock-in in vitro and in vivo.

Results

WGCNA and GO enrichment analysis showed that one co-expression network was significantly enriched for epithelial cell differentiation, among which, TINCR was significantly downregulated. qRT-PCR analyses validated down-regulation of TINCR in tumor tissues compared with paired NATs, and its expression was closely correlated with pathological differentiation and lymph node metastasis in patients with OSCC. Patients with lower TINCR expression levels had worse survival. Cell function experiments showed that TINCR played a crucial role in epithelial differentiation. Both TINCR and epithelial differentiation-associated genes, including IVL and KRT4, were significantly upregulated during OSCC cell calcium-induced differentiation but were reduced when cell dedifferentiation occurred in tumor spheres. Overexpression of TINCR dramatically suppressed cell dedifferentiation, migration and invasion in vitro, while knockdown of TINCR had the opposite effects. Upregulation of TINCR significantly elevated the expression of terminal differentiation genes and repressed tumor growth in vivo. Moreover, TINCR significantly suppressed the activation of JAK2/STAT3 signaling in OSCC cells.

Conclusion

Our study suggests that TINCR functions as a tumor suppressor by inducing cell differentiation through modulating JAK2/STAT3 signaling in OSCC. TINCR may serve as a prognostic biomarker and therapeutic target for OSCC.

LncRNA FER1L4 Promotes Oral Squamous Cell Carcinoma Progression via Targeting miR-133a-5p/Prx1 Axis

Background

Oral squamous cell carcinoma (OSCC) is a common cancer especially young people in the world. The long non-coding RNA Fer-1-like protein 4 (FER1L4) has been reported to be closely associated with the progression of various human cancers. However, the role of FER1L4 in OSCC remains unclear.

Methods

The expression level of FER1L4 in OSCC tissues and cancer cell lines was detected by using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was evaluated by cell counting kit-8 (CCK-8) assay and EdU staining assay. Cell invasion and migration were evaluated by Transwell assay. Cell apoptosis was detected by flow cytometry. Luciferase reporter assay was performed to determine the targeting relationship between FER1L4, miR-133a-5p and Prx1. The protein expression of Prx1 was detected by Western blot. In addition, a xenograft tumor model in vivo was constructed to confirm the function of FER1L4.

Results

FERIL4 was significantly upregulated in OSCC tissues and cancer cell lines. Moreover, high level of FER1L4 predicted a poor prognosis of OSCC patients. Silencing of FER1L4 not only significantly inhibited cell growth, invasion, migration and induced apoptosis in SCC-9 and HN4 cells in vitro, but also effectively suppressed the tumorigenesis of OSCC cells in vivo. Knockdown of FER1L4 significantly enhanced the expression of miR-133a-5p by sponging it, and then downregulated Prx1 expression.

Conclusion

Our study elucidated a new mechanism of lncRNA FER1L4 that promoting OSCC progression by directly targeting miR-133a-5p/Prx1 axis and provided novel therapeutic targets for OSCC.

NF-κB-mediated lncRNA AC007271.3 promotes carcinogenesis of oral squamous cell carcinoma by regulating miR-125b-2-3p/Slug

Oral squamous cell carcinoma (OSCC) is the most common oral cancer. The molecular mechanisms of this disease are not fully understood. Our previous studies confirmed that dysregulated function of long non-coding RNA (lncRNA) AC007271.3 was associated with a poor prognosis and overexpression of AC007271.3 promoted cell proliferation, migration, invasion, and inhibited cell apoptosis in vitro, and promoted tumor growth in vivo. However, the underlying mechanisms of AC007271.3 dysregulation remained obscure. In this study, our investigation showed that AC007271.3 functioned as competing endogenous RNA by binding to miR-125b-2-3p and by destabilizing primary miR-125b-2, resulted in the upregulating expression of Slug, which is a direct target of miR-125b-2-3p. Slug also inhibited the expression of E-cadherin but N-cadherin, vimentin, and β-catenin had no obvious change. The expression of AC007271.3 was promoted by the canonical nuclear factor-κB (NF-κB) pathway. Taken together, these results suggested that the classical NF-κB pathway-activated AC007271.3 regulates EMT by miR-125b-2-3p/Slug/E-cadherin axis to promote the development of OSCC, implicating it as a novel potential target for therapeutic intervention in this disease.

lncRNA MALAT1 promotes cell proliferation and invasion by regulating the miR-101/EZH2 axis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor of the oral cavity. Emerging evidence indicates that long non-coding (lnc)RNAs play a key role in the cellular processes of tumor cells, including glycolysis, growth and movement. Here, the purpose of this study was to explore the biological functions and potential mechanism of lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in OSCC. OSCC tissues and adjacent matched paraneoplastic normal tissues were collected from 20 OSCC patients. The expression of MALAT1 and miR-101 in OSCC tissues and cell lines (HSC3, SCC9, SCC15 and SCC25) were determined by real-time-polymerase chain reaction (qPCR). Caspase-3, xaspase-8 and EZH2 protein levels were determined by western blot analysis. MALAT1-mediated miRNAs were verified by bioinformatics analysis of StarBase and Luciferase reporter assay. Cell Counting Kit-8 (CCK-8) and Transwell assays were used for investigating MALAT1 effect on cell proliferation and invasion in the OSCC cells. qPCR analysis indicated that MALAT1 expression was obviously increased, and miR-101 was decreased in the OSCC tissues and cell lines. Functional studies revealed that overexpression of MALAT1 promoted OSCC cell proliferation and invasion. Further experiments revealed that miR-101 was a target of MALAT1 and that the miR-101 inhibitor abolished the effect of MALAT1 on OSCC cell proliferation and invasion. Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) acted as a downstream effecter of MALAT1 in the OSCC cells. Collectively, these findings revealed that upregulation of MALAT1 facilitated OSCC proliferation and invasion by targeting the miR-101/EZH2 axis.

Long Noncoding RNA RC3H2 Facilitates Cell Proliferation and Invasion by Targeting MicroRNA-101-3p/EZH2 Axis in OSCC

In our previous studies, enhancer of zeste homolog 2 (EZH2) has been proven to be a key oncogenic driver in oral squamous cell carcinoma (OSCC). However, the regulatory mechanisms on EZH2 remain poorly understood in OSCC. Here, through multi-transcriptomics, bioinformatics analysis, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the co-expression network of long noncoding RNA RC3H2 (RC3H2), microRNA-101-3p (miR-101-3p), and EZH2 were screened and validated as a competing endogenous RNA (ceRNA) mechanism in OSCC. Silencing of RC3H2 inhibited OSCC cell proliferation, colony formation, migration, and invasion in vitro and reduced the expression of EZH2 and H3K27Me3, whereas RC3H2 overexpression significantly promoted OSCC cell growth, colony formation, migration, invasion, and xenograft tumor growth in vivo and increased the expression of EZH2 and H3K27Me3. A fluorescence in situ hybridization (FISH) assay verified that RC3H2 was predominately localized to the cytoplasm. RNA pull-down and luciferase activity assays showed that miR-101-3p was physically bound to RC3H2 as well as EZH2, and its inhibitor reversed the inhibitory effect of RC3H2 knockdown on progression of OSCC. Taken together, our findings demonstrate that RC3H2 as completive endogenous RNA sponging miR-101-3p targets EZH2 and facilitates OSCC cells' malignant behavior.

LncRNA BANCR Promotes Pancreatic Cancer Tumorigenesis via Modulating MiR-195-5p/Wnt/β-Catenin Signaling Pathway

Long noncoding BRAF-activated noncoding RNA has been reported to be tightly associated with tumorigenesis and development in various types of cancers. However, the expression, biological function, and modulatory mechanism of BRAF-activated noncoding RNA in pancreatic cancer remained unclear. In the present work, we explored the carcinogenic activity and underlying mechanism of BRAF-activated noncoding RNA on pancreatic cancer in vitro. We identified that BRAF-activated noncoding RNA was upregulated in pancreatic cancer tissues and cell lines, and BRAF-activated noncoding RNA was related to tumor metastasis and stage. BRAF-activated noncoding RNA reinforces proliferation, invasion, and migration in PANC-1 and SW1990 cells. Moreover, miR-195-5p was downregulated in both PC tissues and cell lines. Our results based on luciferase reporter, RIP-Ago2 and qRT-PCR assays, showed that miR-195-5p was a direct target of BRAF-activated noncoding RNA. Furthermore, miR-195-5p inhibitor abrogated the effects of short-interfering BRAF-activated noncoding RNA on PANC-1 and SW1990 cell growth and invasion in vitro. We further identified that BRAF-activated noncoding RNA played a vital role in activating the Wnt/β-catenin pathway by sponging miR-195-5p. Collectively, our study showed that BRAF-activated noncoding RNA promotes pancreatic cancer tumorigenesis through miR-195-5p/Wnt/β-catenin axis may serve as a potential target for diagnostics and therapeutics in pancreatic cancer.

Long non-coding RNA H19, a novel therapeutic target for pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with high mortality, which threats peoples’ health. Unfortunately, the pathogenesis of PDAC remains unclear. Recent studies have indicated that long non-coding RNAs (lncRNAs) can regulate the development and progression of malignant tumors through varying mechanisms. LncRNA H19 has a unique expression profile and can act as a sponger of specific miRNAs to regulate the pathogenic process of many diseases, including PDAC and several other types of cancers. Here, we review the research approaches to understanding the regulatory role of H19 and potential mechanisms in the progression of PDAC and other types of cancers and diseases. These studies suggest that H19 may be a novel therapeutic target for PDAC and our findings may open new revenues for scientific researches and development of valuable therapies for these diseases in the future.

Linc01234 promotes cell proliferation and metastasis in oral squamous cell carcinoma via miR-433/PAK4 axis

Background

Increasing studies have demonstrated that long non-coding RNAs (lncRNAs) play an important role in tumor progression. However, the potential biological functions and clinical importance of Linc01234 in oral squamous cell carcinoma (OSCC) remain unclear.

Methods

We evaluated the expression profile and prognostic value of Linc01234 in OSCC tissues by RT-qPCR. Then, functional in vitro experiments were performed to investigate the effects of Linc01234 on tumor growth, migration and invasion in OSCC. Mechanistically, RT-qPCR, bioinformatic analysis and dual luciferase reporter assays were performed to identify a competitive endogenous RNA (ceRNA) mechanism involving Linc01234, miR-433-3p and PAK4.

Results

We found that Linc01234 was clearly upregulated in OSCC tissues and cell lines, and its level was positively associated with T stage, lymph node metastasis, differentiation and poor prognosis of patients with OSCC. Our results shown that Linc01234 inhibited cell proliferation and metastatic abilities in CAL27 and SCC25 cells following its knockdown. Mechanistic analysis indicated that Linc01234 may act as a ceRNA (competing endogenous RNA) of miR-433-3p to relieve the repressive effect of miR-433-3p on its target PAK4.

Conclusions

Our results indicated that Linc01234 promotes OSCC progression through the Linc01234/miR-433/PAK4 axis and might be a potential therapeutic target for OSCC.

Long non-coding RNA TUSC8 inhibits breast cancer growth and metastasis via miR-190b-5p/MYLIP axis

The lncRNA tumor suppressor candidate 8 (TUSC8) plays a critical role in the development of several cancers. However, the biological functions and underlying molecular mechanisms of TUSC8 with respect to breast cancer remain largely unclear. Here, we found that TUSC8 was significantly down-regulated in breast cancer tissues and its high expression predicted better prognosis of breast cancer patients. Functionally, knock-down of TUSC8 drastically promoted the proliferation, migration and invasion of breast cancer cells in vitro and facilitated tumorigenicity and metastasis in vivo. Mechanistically, the results of luciferase reporter, RIP and RNA pull-down assays proved that TUSC8 functioned as molecular sponge for miR-190b-5p. Furthermore, we showed that TUSC8 served as a competing endogenous RNA (ceRNA) of myosin regulatory light chain interacting protein (MYLIP) through competitively binding with miR-190b-5p and suppressed breast cancer metastasis through regulating the expression of epithelial–mesenchymal transition (EMT) related markers. Clinically, the receiver operating characteristic curve (ROC) analyses revealed that the combination usage of TUSC8 and MYLIP might become novel promising diagnostic biomarkers for breast cancer. Taken together, these results suggested that TUSC8 inhibited breast cancer growth and metastasis via miR-190b-5p/MYLIP axis, providing us new insights into developing potential therapeutic targets for breast cancer patients.

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.

Functional analysis of lncRNAs based on competitive endogenous RNA in tongue squamous cell carcinoma

Backround

Tongue squamous cell carcinoma (TSCC) is the most common malignant tumor in the oral cavity. An increasing number of studies have suggested that long noncoding RNA (lncRNA) plays an important role in the biological process of disease and is closely related to the occurrence and development of disease, including TSCC. Although many lncRNAs have been discovered, there remains a lack of research on the function and mechanism of lncRNAs. To better understand the clinical role and biological function of lncRNAs in TSCC, we conducted this study.

Methods

In this study, 162 tongue samples, including 147 TSCC samples and 15 normal control samples, were investigated and downloaded from The Cancer Genome Atlas (TCGA). We constructed a competitive endogenous RNA (ceRNA) regulatory network. Then, we investigated two lncRNAs as key lncRNAs using Kaplan-Meier curve analysis and constructed a key lncRNA-miRNA-mRNA subnetwork. Furthermore, gene set enrichment analysis (GSEA) was carried out on mRNAs in the subnetwork after multivariate survival analysis of the Cox proportional hazards regression model.

Results

The ceRNA regulatory network consists of six differentially expressed miRNAs (DEmiRNAs), 29 differentially expressed lncRNAs (DElncRNAs) and six differentially expressed mRNAs (DEmRNAs). Kaplan-Meier curve analysis of lncRNAs in the TSCC ceRNA regulatory network showed that only two lncRNAs, including LINC00261 and PART1, are correlated with the total survival time of TSCC patients. After we constructed the key lncRNA-miRNA -RNA sub network, the GSEA results showed that key lncRNA are mainly related to cytokines and the immune system. High expression levels of LINC00261 indicate a poor prognosis, while a high expression level of PART1 indicates a better prognosis.

Long non-coding RNAs in Oral squamous cell carcinoma: biologic function, mechanisms and clinical implications

There is growing evidence that regions of the genome that cannot encode proteins play an important role in diseases. These regions are usually transcribed into long non-coding RNAs (lncRNAs). LncRNAs, little or no coding potential, are defined as capped transcripts longer than 200 nucleotides. New sequencing technologies have shown that a large number of aberrantly expressed lncRNAs are associated with multiple cancer types and indicated they have emerged as an important class of pervasive genes during the development and progression of cancer. However, the underlying mechanism in cancer is still unknown. Therefore, it is necessary to elucidate the lncRNA function. Notably, many lncRNAs dysregulation are associated with Oral squamous cell carcinoma (OSCC) and affect various aspects of cellular homeostasis, including proliferation, survival, migration or genomic stability. This review expounds the up- or down-regulation of lncRNAs in OSCC and the molecular mechanisms by which lncRNAs perform their function in the malignant cell. Finally, the potential of lncRNAs as non-invasive biomarkers for OSCC diagnosis are also described. LncRNAs hold promise as prospective novel therapeutic targets, but more research is needed to gain a better understanding of their biologic function.

Hallmarks of Cancer-Related Newly Prognostic Factors of Oral Squamous Cell Carcinoma

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth leading malignancy worldwide. OSCC is an aggressive tumor and its prognosis has exhibited little improvement in the last three decades. Comprehensive elucidation of OSCC's molecular mechanism is imperative for early detection and treatment, improving patient survival. Based on broadly accepted notions, OSCC arises from multiple genetic alterations caused by chronic exposure to carcinogens. In 2011, research revealed 10 key alterations fundamental to cancer cell development: sustaining proliferative signaling, evading growth suppressors, avoiding immune destruction, activating invasion and metastasis, tumor-promoting inflammation, enabling replicative immortality, inducing angiogenesis, genome instability and mutation, resisting cell death, and deregulating energetics. This review describes molecular pathological findings on conventional and novel hallmarks of OSCC prognostic factors. In addition, the review summarizes the functions and roles of several molecules as novel OSCC prognosticators.

Functional Role of Non-Coding RNAs during Epithelial-To-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is a key biological process involved in a multitude of developmental and pathological events. It is characterized by the progressive loss of cell-to-cell contacts and actin cytoskeletal rearrangements, leading to filopodia formation and the progressive up-regulation of a mesenchymal gene expression pattern enabling cell migration. Epithelial-to-mesenchymal transition is already observed in early embryonic stages such as gastrulation, when the epiblast undergoes an EMT process and therefore leads to the formation of the third embryonic layer, the mesoderm. Epithelial-to-mesenchymal transition is pivotal in multiple embryonic processes, such as for example during cardiovascular system development, as valve primordia are formed and the cardiac jelly is progressively invaded by endocardium-derived mesenchyme or as the external cardiac cell layer is established, i.e., the epicardium and cells detached migrate into the embryonic myocardial to form the cardiac fibrous skeleton and the coronary vasculature. Strikingly, the most important biological event in which EMT is pivotal is cancer development and metastasis. Over the last years, understanding of the transcriptional regulatory networks involved in EMT has greatly advanced. Several transcriptional factors such as Snail, Slug, Twist, Zeb1 and Zeb2 have been reported to play fundamental roles in EMT, leading in most cases to transcriptional repression of cell⁻cell interacting proteins such as ZO-1 and cadherins and activation of cytoskeletal markers such as vimentin. In recent years, a fundamental role for non-coding RNAs, particularly microRNAs and more recently long non-coding RNAs, has been identified in normal tissue development and homeostasis as well as in several oncogenic processes. In this study, we will provide a state-of-the-art review of the functional roles of non-coding RNAs, particularly microRNAs, in epithelial-to-mesenchymal transition in both developmental and pathological EMT.