Long noncoding RNA FALEC inhibits proliferation and metastasis of tongue squamous cell carcinoma by epigenetically silencing ECM1 through EZH2

Long non-coding RNAs in cancer: multifaceted roles and potential targets for immunotherapy

Cancer remains a major global health concern with high mortality rates mainly due to late diagnosis and poor prognosis. Long non-coding RNAs (lncRNAs) are emerging as key regulators of gene expression in human cancer, functioning through various mechanisms including as competing endogenous RNAs (ceRNAs) and indirectly regulating miRNA expression. LncRNAs have been found to have both oncogenic and tumor-suppressive roles in cancer, with the former promoting cancer cell proliferation, migration, invasion, and poor prognosis. Recent research has shown that lncRNAs are expressed in various immune cells and are involved in cancer cell immune escape and the modulation of the tumor microenvironment, thus highlighting their potential as targets for cancer immunotherapy. Targeting lncRNAs in cancer or immune cells could enhance the anti-tumor immune response and improve cancer immunotherapy outcomes. However, further research is required to fully understand the functional roles of lncRNAs in cancer and the immune system and their potential as targets for cancer immunotherapy. This review offers a comprehensive examination of the multifaceted roles of lncRNAs in human cancers, with a focus on their potential as targets for cancer immunotherapy. By exploring the intricate mechanisms underlying lncRNA-mediated regulation of cancer cell proliferation, invasion, and immune evasion, we provide insights into the diverse therapeutic applications of these molecules.

Brucea javanica oil inhibits tongue squamous cell invasion and metastasis by regulating miR-138-EZH2 pathway

Tongue squamous cell carcinoma (TSCC) is one of the most common malignant tumors of head and neck. Its incidence is on the rise, and the proportion of young patients is gradually increasing, which is prone to tumor recurrence and metastasis. At present, there is no effective method to completely treat TSCC. Studies have shown that brucea javanica oil (BJO) has good antitumor activity against lung cancer and gastrointestinal tumors, but its therapeutic effect on TSCC is not clear. We have previously confirmed that oleic acid, the main component of BJO, can induce apoptosis of TSCC and reduce its invasion and metastasis ability. However, the anticancer effect and mechanism of BJO in TSCC remain unclear. In order to further explore the effects of BJO on the biological characteristics of TSCC cells, we studied the effects of different concentrations of BJO on the migration, invasion ability and epithelial mesenchymal transition (EMT) progression of TSCC cells and the possible mechanisms through in vitro experiments. We found that BJO could inhibit the invasion and metastasis of TSCC and up-regulate miR-138. After BJO treatment, the expression of E-cad was significantly increased, while the expression of EZH2, Slug, p-ERK1/2 and Vimentin was significantly decreased. EZH2 is a miR-138 target gene involved in TSCC. BJO inhibits TSCC invasion and metastasis by regulating the miR-138-EZH2 pathway. In vivo experiments have also well demonstrated the targeting effect of this pathway. This study provides a new therapeutic strategy for the treatment of TSCC.

LncRNA FALEC increases the proliferation, migration and drug resistance of cholangiocarcinoma through competitive regulation of miR-20a-5p/SHOC2 axis

BACKGROUND

LncRNA is an important regulatory factor in the human genome. We aim to explore the roles of LncFALEC and miR-20a-5p/SHOC2 axis on the proliferation, migration, and Fluorouracil (5-FU) resistance of cholangiocarcinoma (CCA).

METHODS

In this study, the expression of FALEC and miR-20a-5p in CCA tissues and cell lines (HuCCT1, QBC939, and Huh-28) was detected by RT-qPCR. The FALEC in 5-FU-resistant CCA cell lines (QBC939-R, Huh-28-R) was knocked down to evaluate its effects on cell proliferation, migration, invasion, and drug resistance.

RESULTS

Our analysis showed that compared with the adjacent non-tumor tissues, FALEC was significantly higher in the CCA tissues and even higher in the samples from 5-FU-resistant patients. Knockdown FALEC increased the sensitivity of 5-FU and decreased migration and invasion of CCA cells. Dual luciferase reporter confirmed that FALEC sponges miR-20a-5p and down-regulated its expression. Moreover, SHOC2 leucine-rich repeat scaffold protein (SHOC2) was the target gene of miR-20a-5p. We found overexpression of FALEC (FALEC-OE) increased resistance of CCA cells to 5-FU significantly, which might contribute to increased SHOC2 expression and activation of the ERK1/2 signaling pathway.

CONCLUSIONS

In summary, our study revealed that down-regulation of FALEC could inhibit the proliferation, migration, and invasion of CCA cells in vitro by regulating the miR-20a-5p/SHOC2 axis and participating in 5-FU resistance by mediating the ERK1/2 signaling pathway.

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.

lncKRT16P6 promotes tongue squamous cell carcinoma progression by sponging miR‑3180 and regulating GATAD2A expression

Tongue squamous cell carcinoma (TSCC) is characterized by a poor prognosis and its 5‑year overall survival rate has not improved significantly. However, the precise molecular mechanisms underlying TSCC remain largely unknown. Through RNA screening, the present study identified a novel long noncoding RNA (lncRNA), keratin 16 pseudogene 6 (lncKRT16P6), which was upregulated in TSCC tissues and cell lines and associated with TSCC tumor stage and differentiation grade. Inhibition of lncKRT16P6 expression reduced TSCC cell migration, invasion and proliferation. lncKRT16P6 sponged microRNA (miR)‑3180 and upregulated GATA zinc finger domain containing 2A (GATAD2A) expression. miR‑3180 inhibition reversed the lncKRT16P6 depletion‑induced attenuation of TSCC malignancy and GATAD2A depletion reversed the miR‑3180 silencing‑induced enhancement of TSCC malignancy. In summary, the present study revealed a potential competitive endogenous RNA (ceRNA) regulatory pathway in which lncKRT16P6 modulates GATAD2A expression by binding miR‑3180, ultimately promoting tumorigenesis and metastasis in TSCC. Therefore, lncKRT16P6 may be used as a prognostic biomarker and therapeutic target for clinical intervention in TSCC.

EZH2 suppresses insulinoma development by epigenetically reducing KIF4A expression via H3K27me3 modification

Kinesin family member 4A (KIF4A), located in the human chromosome band Xq13.1, is aberrantly overexpressed in various cancers. Our study intended to assess the expression of KIF4A in insulinoma and to gain new insights into the molecular mechanisms of this rare disease. First, KIF4A was significantly recruited in pancreatic endocrine cells relative to other cell types. A significant correlation existed between the overexpression of KIF4A and the poor survival of pancreatic adenocarcinoma patients. As revealed by CCK-8, TUNEL assay, flow cytometry, wound healing, Matrigel-transwell, senescence-associated β-galactosidase staining, ELISA, and subcutaneous tumor formation analysis in nude mice, knocking down KIF4A significantly inhibited the growth and metastasis of insulinoma cells in vivo and in vitro. Mechanistically, we observed that KIF4A promoter sequences had reduced H3K27me3 modifications, and decline in enhancer of zeste homolog-2 (EZH2) expression promoted KIF4A expression by reducing the modification, thus leading to insulinoma. Moreover, EZH2 knockdown-induced insulinoma cell proliferation was dependent on KIF4A overexpression since KIF4A knockdown eradicated shEZH2-induced proliferation of insulinoma cells. In summary, KIF4A was identified as a possible therapeutic target for insulinoma.

CTBP1-AS2 promoted non-small cell lung cancer progression via sponging the miR-623/MMP3 axis

Mounting evidence indicates that lncRNAs (long noncoding RNAs) are involved in the initiation and development of tumors, including non-small cell lung cancer (NSCLC). However, the involvement of C-terminal binding protein-antisense RNA 2 (CTBP1-AS2) in NSCLC remains to be studied. RT-qPCR was carried out to detect CTBP1-AS2 and miR-623 expression in NSCLC cells and tissues. CCK-8 and flow cytometry were performed to measure cell proliferation and cell cycle progression. Luciferase reporter analysis was performed to study the potential target of CTBP1-AS2. We found that CTBP1-AS2 expression was upregulated in NSCLC cells (SPC-A1, A549, H23, and H1299) compared to 16HBE cells. We demonstrated that the CTBP1-AS2 level was higher in NSCLC specimens than in paired non-tumor specimens. Elevated expression of CTBP1-AS2 increased cell growth and induced cell cycle progression and epithelial-mesenchymal transition (EMT). We also found that ectopic expression of CTBP1-AS2 inhibited miR-623 expression. MMP3 was a direct target of miR-623, and luciferase reporter assays suggested that miR-623 overexpression suppressed the luciferase expression driven by the MMP3 wild-type reporter but not the mutant reporter. Overexpression of miR-623 suppressed MMP3 expression in A549 cells, and overexpression of CTBP1-AS2 increased MMP3 expression in A549 cells. Moreover, the miR-623 level was lower in NSCLC specimens than in paired non-tumor specimens, and CTBP1-AS2 expression was negatively correlated with miR-623 expression in NSCLC samples. Furthermore, overexpression of CTBP1-AS2 enhanced cell growth, cell cycle progression, and EMT progression by modulating MMP3 expression.

Role of the Tumor Microenvironment and the Influence of Epigenetics on the Tumor Microenvironment in Oral Carcinogenesis: Potential Implications

Oral cancer has become a significant problem throughout the world, particularly in countries that are still developing. Recent literature supports the contribution of components of the tumor microenvironment (TME) and the effect of epigenetic changes happening in the cells of the TME on oral cancer development and progression. In this review, we comprehensively examine the significance of TME in the development of OC along with the current understanding of the epigenetic modifications that regulate the TME and their cohesive impact on tumor traits and their potential as therapeutic targets.

Focally amplified long non-coding RNA in epithelial cancer as a potential biomarker and therapeutic target

Deregulation of long non-coding RNAs (lncRNAs) has been implicated in tumorigenesis. FALEC is a lncRNA upregulated in multiple cancer types. FALEC functions as an oncogene through various mechanisms, such as competitively binding miRNAs and regulation of PI3K/AKT, Tp53 and phosphatase and tensin homolog signaling pathways. Pertinent to clinical practice, the use of FALEC as a putative biomarker has been identified. These findings suggested that FALEC might play a pivotal role in human cancers. Further studies are warranted to examine the diagnostic and prognostic performance of FALEC as a noninvasive biomarker in liquid biopsy samples and promote its development to be a clinically utilizable prognostic cancer biomarker and molecular therapeutic target.

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 CASC21 induces HGH1 to mediate colorectal cancer cell proliferation, migration, EMT and stemness

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs) have been increasingly reported to serve vital parts in malignancies including CRC. Although cancer susceptibility 21 (CASC21) has been uncovered to play a part in CRC, its mechanism still needs further explanation. Thus, our study aimed to further explore the influence and mechanism of CASC21 in CRC progression. Quantitative real-time RT-PCR and western blot were performed to detect gene expression; a series of functional assays were performed to investigate the effect of CASC21 on CRC cells; in vivo tumour growth was evaluated via the nude mice xenograft model. The results revealed that CASC21 facilitated CRC cell proliferation, migration, epithelial-mesenchymal transition (EMT) and stemness. In addition, CASC21 was co-expressed with and bound to transcription factor POU5F1B (POU class 5 homeobox 1B). CASC21 recruited POU5F1B to HGH1 promoter to activate the transcription of HGH1 homolog. Also, CASC21 served as a competitive endogenous RNA (ceRNA) to up-regulate HGH1 via endogenously sponging miR-485-5p. Moreover, HGH1 overexpression counteracted the suppression of CASC21 deficiency on CRC tumour growth. In summary, our study indicated that CASC21 enhanced the expression of HGH1 to promote the malignancy of CRC by recruiting POU5F1B and sponging miR-485-5p, suggesting a key role of CASC21 in CRC progression.

Long Non-Coding RNA Myosin Light Chain Kinase Antisense 1 Plays an Oncogenic Role in Gallbladder Carcinoma by Promoting Chemoresistance and Proliferation

Background

Long non-coding RNAs (lncRNAs) have been reported to play critical roles in human tumours, including gallbladder carcinoma (GBC). However, their biological functions and molecular mechanisms in tumorigenesis and progression remain largely unknown.

Methods

Quantitative polymerase chain reaction (qPCR) was used to verify the expression of lncRNA myosin light chain kinase antisense RNA 1 (MYLK-AS1) in 120 pairs of GBC tissues and paired adjacent non-tumour tissues, as well as in six different GBC cell lines (NOZ, EH-GB1, OCUG-1, GBC-SD, SGC-996 and QBC-939). Cell counting kit 8 was applied to explore cell proliferation and drug sensitivity assays. The target miRNAs (miR) of MYLK-AS1 and downstream target genes were predicted using Starbase 3.0 software and confirmed by double luciferase reporting test. The expression of proteins was assessed using Western blot assay.

Results

Here, we demonstrated that MYLK-AS1 was significantly upregulated and correlated with a poor prognosis and poor clinical characteristics in GBC. Furthermore, the forced expression of MYLK-AS1 significantly promoted GBC cell proliferation and resistance to gemcitabine in vitro. Mechanistically, MYLK-AS1 functioned as an efficient miR-217 sponge, thereby releasing the inhibition of enhancer of zeste 2 polycomb repressive complex 2 (EZH2) subunit expression. MYLK-AS1 promoted GBC cell proliferation and resistance to gemcitabine by upregulating EZH2 expression, and EZH2 was confirmed as a direct target of miR-217.

Discussion

Our results confirmed that the chemoresistant driver MYLK-AS1 might be a promising candidate as a therapeutic target for the treatment of advanced GBC.

LINC01783 accelerated tongue squamous cell carcinoma progression via inhibiting miR-199b-5p

Growing studies illustrated that lncRNAs exert critical roles in development and occurrence of tumours including TSCC. In this research, we indicated that LINC01783 was up‐regulated in TSCC cells (SCC1, Cal27, UM1 and SCC4) when compared to NHOK cell. RT‐qPCR analysis indicated that LINC01783 was overexpressed in 22 TSCC cases (73.3%, 22/30) compared with no‐tumour specimens. LINC01783 level was up‐regulated in TSCC specimens when compared to no‐tumour specimens. Ectopic expression of LINC01783 promoted TSCC cell cycle and growth and EMT progression in both TSCC cell SCC1 and Cal27. Overexpression of LINC01783 sponged miR‐199b‐5p in TSCC cell and elevated expression of LINC01783 inhibited miR‐199b‐5p expression. Moreover, we illustrated that miR‐199b‐5p was down‐regulated in TSCC cells and specimen and LINC01783 level was up‐regulated in TSCC specimens when compared to no‐tumour specimens. Elevated expression of LINC01783 promoted TSCC cell growth, cycle and EMT progression by sponging miR‐199b‐5p. These data suggested that LINC01783 functioned as one oncogene and might be one treatment target for TSCC.

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.

Long non-coding RNAs in head and neck squamous cell carcinoma: Diagnostic biomarkers, targeted therapies, and prognostic roles

At present, emerging evidence shows that non-coding RNAs (ncRNAs) play crucial roles for development of multiple tumors. Amongst these ncRNAs, long non-coding RNAs (lncRNAs) play prominent roles in physiological and pathological processes. LncRNAs are RNA transcripts larger than 200 nucleotides and have been shown to serve important regulatory roles in different types of cancer via interactions with DNA, RNA and proteins. Head and neck squamous cell carcinoma (HNSCC) is one of the most malignant tumors with low survival rates in advanced stages. Recently, lncRNAs have been demonstrated to be involved in a wide range of biological processes, including proliferation, metastasis, and prognosis of HNSCC. Therefore, this review describes molecular mechanisms of up- or down-regulation of lncRNAs and expounds their functions in pathology and clinical practices in HNSCC. It also highlights their potential clinical applications as biomarkers for the diagnosis, prognosis, and treatment of HNSCC. However, studies on lncRNAs are still not comprehensive, and more investigations are needed in the future.

LUCAT1 as an oncogene in tongue squamous cell carcinoma by targeting miR-375 expression

Emerging studies suggested that lncRNAs play a crucial molecular role in cancer development and progression. LncRNA LUCAT1 has been proved as oncogenic molecular in lung cancer, glioma, osteosarcoma, renal carcinoma and oesophageal squamous cell carcinoma. However, its roles and function mechanisms in tongue squamous cell carcinoma (TSCC) are still unknown. We showed that the expression of LUCAT1 was up‐regulated in the TSCC cells and tissues and the higher LUCAT1 expression was associated with the poor overall survival (OS). Knockdown expression of LUCAT1 suppressed TSCC cell proliferation, cycle and migration. In addition, we demonstrated that miR‐375 overexpression inhibited the luciferase activity of LUCAT1 wild‐type and knockdown LUCAT1 promoted the miR‐375 expression in TSCC cell. Furthermore, we indicated that miR‐375 expression was down‐regulated in the TSCC cell lines and tissues and the lower expression of miR‐375 was associated with poor OS. The expression of miR‐375 was inversely correlated with LUCAT1 expression in the TSCC tissues. Knockdown LUCAT1 promoted TSCC cell proliferation, cell cycle and migration partly through regulating miR‐375 expression. In summary, this study suggested the tumorigenic effect of lncRNA LUCAT1 in TSCC cells by targeting miR‐375 expression.

LncRNA NOP14-AS1 Promotes Tongue Squamous Cell Carcinoma Progression by Targeting MicroRNA-665/HMGB3 Axis

Purpose

The expression profile, clinical effects, and detailed roles of NOP14 antisense RNA 1 (NOP14-AS1) in tongue squamous cell carcinoma (TSCC) remain ambiguous and need to be further explored. Thus, this work was initiated to offer further solid evidence regarding the expression and roles of NOP14-AS1 in TSCC. Furthermore, additional efforts were exerted to reveal the molecular events by which NOP14-AS1 affects the malignant behaviours of TSCC.

Methods

NOP14-AS1 expression was detected in TSCC tissues and cell lines using quantitative reverse transcription-polymerase chain reaction. Cell Counting Kit-8 assay, flow cytometric analysis, Transwell migration and invasion assays, and xenograft tumor model analysis were performed to assess the malignant biological behaviors of TSCC cells after NOP14-AS1 depletion. Mechanistic studies were performed using bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation, and rescue experiments.

Results

NOP14-AS1 upregulation was identified in TSCC tissues and cell lines. Patients with TSCC exhibiting a high NOP14-AS1 expression faced shorter overall survival than those with a low NOP14-AS1 expression. Functionally, NOP14-AS1 depletion facilitated apoptosis and impeded cell proliferation, migration, and invasion in TSCC. In vivo, the growth of TSCC cells was hindered by NOP14-AS1 depletion. Mechanically, NOP14-AS1 functioned as a competing endogenous RNA by sponging microRNA-665 (miR-665), thereby overexpressing the target high mobility group box 3 (HMGB3) of miR-665. Lastly, rescue experiments confirmed that the introduction of HMGB3 overexpression plasmid or miR-665 inhibitor could abrogate the inhibition of aggressive phenotypes triggered by NOP14-AS1 knockdown.

Conclusion

NOP14-AS1 executed pro-oncogenic activities in TSCC cells by targeting the miR-665/HMGB3 axis. The NOP14-AS1/miR-665/HMGB pathway may be a valuable prognostic indicator and therapeutic target for preventing TSCC.

LINC00460 facilitated tongue squamous cell carcinoma progression via the miR-320b/IGF2BP3 axis

OBJECTIVE

We aimed to explore the role of long intergenic non-protein coding RNA 460 (LINC00460) in tongue squamous cell carcinoma (TSCC).

METHODS

We enrolled 27 TSCC patients to explore LINC00460 expression in clinical TSCC samples. RT-qPCR measured expression of molecules in this research. Loss-of-function assays explored biological function of LINC00460 in TSCC cells. RNA pull-down assay, luciferase reporter assay, and RIP assay investigated mechanism of LINC00460 underlying TSCC cells.

RESULTS

TSCC tissues and cell lines both showed high expression of LINC00460. Functionally, LINC00460 downregulation inhibited TSCC cell growth and promoted TSCC cell apoptosis. Additionally, LINC00460 silencing suppressed tumor growth in vivo. Mechanistically, LINC00460 bound with microRNA 320b (miR-320b) in TSCC cells. MiR-320b overexpression suppressed TSCC cell growth and promoted TSCC cell apoptosis. Moreover miR-320b targeted insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) 3'untranslated region in TSCC cells. Furthermore, IGF2BP3 silencing suppressed TSCC cell growth and promoted TSCC cell apoptosis. IGF2BP3 upregulation countervailed effects of silenced LINC00460 on TSCC cells. The LINC00460/miR-320b/IGF2BP3 axis was associated with lymph node metastasis of TSCC patients.

CONCLUSION

Our research illustrated that LINC00460 facilitated TSCC progression via the miR-320b/IGF2BP3 axis, highlighting a potential insight for the treatment of TSCC.

Long Intergenic Non-Protein Coding RNA 519 Promotes the Biological Activities of Tongue Squamous Cell Carcinoma by Sponging microRNA-876-3p and Consequently Upregulating MACC1

Purpose

Long intergenic non-protein coding RNA 519 (LINC00519) promotes the development of lung squamous cell carcinoma. In this study, we detected the expression of LINC00519 in tongue squamous cell carcinoma (TSCC) and examined its clinical significance. Additionally, the regulatory effects of LINC00519 on behaviors of TSCC tumor cells were explored through functional experiments. Finally, mechanistic studies were performed to elucidate the molecular events underlying the tumor-promoting actions of LINC00519 in TSCC.

Materials and Methods

The expression of LINC00519 in TSCC tissues and cell lines was determined using quantitative reverse transcription-polymerase chain reaction. Cell counting kit-8 assay, flow cytometric analysis, cell migration and invasion assays and xenograft tumor model analyses were used to detect TSCC cell proliferation, apoptosis, migration and invasion and in vivo tumor growth, respectively. Mechanistic studies were performed using bioinformatics analysis, RNA immunoprecipitation assay, luciferase reporter assay and rescue experiments.

Results

LINC00519 was overexpressed in both TSCC tissues and cell lines. A high LINC00519 level was associated with poor overall survival in patients with TSCC. In vitro, LINC00519 played cancer-promoting roles in TSCC progression by facilitating cell proliferation, migration and invasion and restraining cell apoptosis. In vivo, LINC00519 downregulation resulted in decreased TSCC tumor growth. Mechanistically, LINC00519 acted as a competing endogenous RNA for microRNA-876-3p (miR-876-3p), which directly targets metastasis associated with colon cancer-1 (MACC1), in TSCC cells. LINC00519 upregulated the expression of MACC1 in TSCC cells by sequestering miR-876-3p. Rescue experiments further affirmed that miR-876-3p inhibition or MACC1 overexpression mitigated the inhibitory influences of LINC00519 depletion on cell proliferation, migration and invasion and neutralized the promoting actions of LINC00519 knockdown on cell apoptosis in TSCC.

Conclusion

LINC00519 aggravated the oncogenicity of TSCC by regulating the miR-876-3p/MACC1 axis. Our findings suggest that the LINC00519/miR-876-3p/MACC1 pathway may be an underlying therapeutic target in TSCC.

Long non-coding RNA FALEC promotes colorectal cancer progression via regulating miR-2116-3p-targeted PIWIL1

BACKGROUND

Colorectal cancer (CRC) is one of the most common digestive malignant tumors globally. Focally amplified lncRNA on chromosome 1 (FALEC) is a novel lncRNA that has been reported to be involved in many biological processes during carcinogenesis. However, its role in CRC remains poorly understood.

METHODS

Gene expression at mRNA or protein level was measured by qRT-PCR or western blot, respectively. In vitro experiments including EdU, colony formation, flow cytometry, wound-healing and transwell assays, as well as in vivo xenograft experiment, were utilized to determine the functional role of FALEC in CRC. Relevant mechanical assays were performed to investigate the underlying molecular mechanism.

RESULTS

FALEC was aberrantly up-regulated in CRC. FALEC knockdown could impair CRC cell proliferation, migration and invasion, whereas facilitate cell apoptosis. MiR-2116-3p was revealed to be sponged by FALEC. PIWIL1 was identified as the target of miR-2116-3p. Mechanically, FALEC restored the expression of PIWIL1 via absorbing miR-2116-3p. MiR-2116-3p inhibition and PIWIL1 enrichment could counteract the anti-tumor impact induced by silenced FALEC on the oncogenic behaviors of CRC cells.

CONCLUSION

Our study revealed that FALEC promoted CRC progression via restoring the expression of miR-2116-3p-targeted PIWIL1, suggesting the potential application of targeting FALEC in the treatment of CRC.

Analysis of Differentially Expressed Long Non-coding RNAs and the Associated TF-mRNA Network in Tongue Squamous Cell Carcinoma

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) play crucial roles in tongue squamous cell carcinoma (TSCC) tumorigenesis. However, the comprehensive regulation of lncRNAs-transcription factors (TFs)-messenger RNAs (mRNAs) in TSCC remains largely unknown. The purpose of this study was to identify aberrantly expressed lncRNAs and the associated TF-mRNA network in TSCC. To explore lncRNA and mRNA expression profiles and their biological functions in TSCC, we surveyed the lncRNA and mRNA expression profiles of TSCC and adjacent tissues using next-generation RNA sequencing in six patients. Thousands of significantly differentially expressed lncRNAs (DELs) and mRNAs (DEGs) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to demonstrate the principal functions of the significantly dysregulated lncRNAs and genes. A total of 40 DELs were screened between TSCC and adjacent non-cancerous tissues. Results obtained from GEPIA and StarBase confirmed the expression levels of nine pivotal DELs obtained in our study. Three of the nine deregulated DELs were identified to have a significant impact on the overall survival of TSCC patients, which were evaluated with GEPIA and StarBase. LncMAP was used to predict the lncRNA-TF-mRNA triplets in TSCC. Furthermore, based on these results, we established lncRNA-TF-mRNA coexpression networks for the up- and downregulated lncRNAs using Cytoscape. We also found that among the nine pivotal lncRNAs, there is limited research on the abnormally expressed lncRNAs, including RP11-54H7.4, CTD-2545M3.8, RP11-760H22.2, RP4-791M13.3, and LINC01405, in TSCC pathogenesis. This is the first study to show that RP11-54H7.4, LINC00152, and LINC01405 can be acted as a prognostic target for TSCC. Our findings provide a novel perspective and lay the foundation for future research on the potential roles of lncRNAs, TFs, and mRNAs in TSCC. Verification of the potential lncRNA-TF-mRNA regulatory networks will provide a more comprehensive understanding of the pathogenesis of TSCC.

Noncoding RNAs in oral premalignant disorders and oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) has the highest mortality rate among all head and neck cancers and a relatively low five-year survival rate. Generally, the development of an oral mucosal malignancy represents a multistep process beginning with normal oral mucosa epithelium and culminating in OSCC after transitioning through intermediary oral premalignant disorders (OPMDs), during which dysplasia is often observed. Noncoding RNAs (ncRNAs) are RNAs that are not translated into proteins, but still can participate in regulating neoplastic cell behavior. Recently, data have emerged on the role of ncRNAs in the progression of oral mucosal malignant diseases, but the exact mechanisms through which ncRNAs are involved remain to be elucidated.

CONCLUSIONS

Knowledge on ncRNAs has added an extra layer of complexity to our understanding of the malignant progression of oral mucosal diseases. The identification of ncRNAs in multiple body fluids as biomarkers may provide new diagnostic options that can be used for the diagnosis and prognosis of OPMDs and OSCC, respectively. Despite overall advances that have been made in cancer treatment, the treatment options for OPMDs and OSCC are still limited. Several studies have shown that ncRNA-based treatment regimens may hold promise as alternative methods for treating OPMDs and OSCC. The use of ncRNAs as therapeutic agents, including miR-155, miR-34 and lncRNA HOTAIR, appear promising.

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.

lncRNA SNHG7 affects malignant tumor behaviors through downregulation of EZH2 in uveal melanoma cell lines

Previous studies have demonstrated that the long non-coding RNA, small nucleolar RNA host gene 7 (SNHG7) plays an important role in several types of cancer; however, its role in the development of uveal melanoma (UM) remains unclear. The present study investigated the effect of SNHG7 on the prognosis of UM, as well as on cell proliferation, cell cycle and apoptosis of UM cell lines. Furthermore, the present study aimed to determine the molecular mechanisms underlying these effects. The association between SNHG7 and prognosis of UM was analyzed using detailed SNHG7 mRNA expression data and clinical information from The Cancer Genome Atlas database. Reverse transcription-quantitative PCR was used in order to detect the differential expression of SNHG7 in UM tissues and cell lines. Cell proliferation was detected using Cell Counting Kit-8 assays, following overexpression of SNHG7. A cell cycle assay was performed using propidium iodide/RNase staining. An apoptosis assay was performed using the Annexin-V-Fluorescein isothiocyanate apoptosis detection kit. The expression of enhancer of zeste homolog 2 (EZH2) was measured via western blotting. The results of the present study indicated that low expression of SNHG7 was associated with poor prognosis. Furthermore, increasing the expression of SNHG7 inhibited the proliferation of UM cells, suppressed cell cycle progression and promoted apoptosis. Western blot analysis results revealed that overexpression of SNHG7 downregulated EZH2 protein expression levels in UM cell lines. The results of the present study demonstrated that SNHG7 inhibited malignant transformation of UM cells by regulating EZH2 expression.

The role of long non-coding RNA H19 in breast cancer

Breast cancer is the most common malignant tumor in women in the majority of countries, such as China, Britain and Australia, and its morbidity and mortality rates remain very high. Long non-coding RNAs (lncRNAs) are non-coding RNAs (ncRNAs) >200 nucleotides in length that lack open reading frames. LncRNA H19 is a transcription product of the H19 gene, and the aberrant expression of H19 can be demonstrated in various types of tumor cell. The purpose of the present review was to elaborate the role of H19 in breast cancer. H19 can regulate gene expression in breast cancer at multiple levels, including epigenetic, transcriptional and posttranscriptional. The abnormal expression of H19 is closely associated with the tumorigenesis and progression of breast cancer via different underlying molecular mechanisms, such as encoding microRNA-675, competing endogenous RNA regulation and interacting with MYC. A large number of clinical studies have suggested that H19 can serve as a potential biomarker for the diagnosis of breast cancer. High expression levels of H19 increases the drug resistance of breast cancer cells and is associated with poor prognosis within patients with breast cancer. Therefore, serum H19 levels may have momentous significance in the clinical setting.