Potential role of differentially expressed lncRNAs in the pathogenesis of oral squamous cell carcinoma

SNAI2/FTH1P3/miR-218-5p Positive Feedback Loop Promotes Colorectal Cancer Metastasis

Colorectal cancer (CRC) is a type of intestinal cancer that causes more than 600,000 deaths every year. Overcoming the problems of metastasis requires detailed studies to reveal the potential molecular mechanisms. This study aims to reveal the molecular mechanism of CRC metastasis involving non-coding RNA regulation. The expression profile of FTH1P3 was analyzed based on the data of TCGA-COAD patient cohorts. Q-PCR analysis was performed to validate the expression of FTH1P3 in colorectal cancer cells. JASPR was used to screen transcription factors of FTH1P3. q-ChIP analysis was used to validate the target between FTH1P3 and transcription factor. Scratch assay and transwell assay were used to evaluate the migration and invasion ability of colorectal cancer cells. FTH1P3 is highly expressed in CRC patient cohort. FTH1P3 induced migration and invasion of SW480 cell through regulating epithelial-mesenchymal transition (EMT). In addition, FTH1P3 is a direct target of SNAI2. SNAI2 promotes the expression of FTH1P3. Both FTH1P3 and SNAI2 were directly targeted and repressed by miR-218-5p. Interestingly, ectopic FTH1P3 caused a decreased miR-218-5p level and an elevated nucleic SNAI2 protein expression level. Of note, only ectopic SNAI2 protein resulted in a repressed miR-218-5p and an increased FTH1P3, whereas SNAI2 3'UTR failed to affect the expression of miR-218-5p and FTH1P3. SNAI2 transcriptionally activates FTH1P3 expression. Both SNAI2 and FTH1P3 are targets of miR-218-5p. SNAI2/FTH1P3/miR-218-5p form a positive feedback loop in the regulation of CRC metastasis.

LncRNA FTH1P3: A New Biomarker for Cancer-Related Therapeutic Development

Cancer is a persistent and urgent health problem that affects the entire world. Not long ago, regulatory biomolecules referred to as long noncoding RNAs (lncRNAs) might have value for their innate abundance and stability. These single-stranded RNAs potentially interfere with several physiological and biochemical cellular processes involved in many human pathological situations, particularly cancer diseases. Ferritin heavy chain1 pseudogene 3 (FTH1P3), a lncRNA that is ubiquitously transcribed and belongs to the ferritin heavy chain (FHC) family, represents a novel class of lncRNAs primarily found in oral squamous cell carcinoma. Further research has shown that FTH1P3 is involved in other malignancies such as uveal melanoma, glioma, esophageal squamous cell carcinoma, non-small cell lung cancer, breast cancer, laryngeal squamous cell carcinoma, and cervical cancer. Accordingly, FTH1P3 significantly enhances cancer symptoms, including cell proliferation, invasion, metastasis, chemoresistance, and inhibition of apoptosis through many specific mechanisms. Notably, the clinical data significantly demonstrated the association of FTH1P3 overexpression with poor prognosis and poor overall survival within the examined samples. Here, we summarize all the research published to date (13 articles) on FTH1P3, focusing on the biological function underlying the regulatory mechanism and its possible clinical relevance.

Posttranscriptional Regulation of the Plasminogen Activation System by Non-Coding RNA in Cancer

Various species of non-coding RNAs (ncRNAs) may act as functional molecules regulating diverse biological processes. In cancer cell biology, ncRNAs include RNAs that regulate the expression of oncogenes and tumor suppressor genes through various mechanisms. The urokinase (uPA)-mediated plasminogen activation system (PAS) includes uPA, its inhibitors PAI-1 and PAI-2 and its specific cellular receptor uPAR; their increased expression represents a negative prognostic factor in several cancers. Here, we will briefly describe the main uPA-mediated PAS components and ncRNA species; then, we will review more recent evidence of the roles that ncRNAs may play in regulating the expression and functions of uPA-mediated PAS components in cancer.

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.

A long noncoding RNA GTF2IRD2P1 suppresses cell proliferation in bladder cancer by inhibiting the Wnt/β‑catenin signaling pathway

Background

There is growing evidence that long non-coding RNAs (LncRNAs) are key in the development of a variety of human tumors. However, the role of lncRNA GTF2IRD2P1 has not been well studied in cancer. The impact of GTF2IRD2P1 on the biological function and clinical relevance in bladder cancer is largely unknown. This study aimed to investigate the biological role of GTF2IRD2P1 in bladder evolution and carcinogenesis.

Methods

We used bioinformatics to obtain the lncRNA GTF2IRD2P1 from bladder urothelial carcinoma (BLCA) in The Cancer Genome Atlas (TCGA) database. The expression of lncRNA GTF2IRD2P1 was detected by qRT-PCR. The CCK8 assay and flow cytometry were used to detect the lncRNA GTF2IRD2P1 function on the proliferation of bladder cancer cells. A western blot was used to calculate the protein level of cell cycle proteins and Wnt signaling pathway proteins. The effect of lncRNA GTF2IRD2P1 on tumorigenesis of bladder cancer was confirmed by a xenograft nude mouse model.

Results

GTF2IRD2P1 expression was found to be lower in both human bladder cancer tissues and cell lines (UM-UC-3, RT4, and 5637), and elevated in T24 compared to the corresponding normal controls. GTF2IRD2P1 expression was also enhanced after transfection of UM-UC-3 cells with the overexpression vector. Meanwhile, overexpression of GTF2IRD2P1 inhibited the proliferation of UM-UC-3 and prolonged the cell cycle. The silencing of GTF2IRD2P1 significantly increased the proliferation and shortened the cell cycle of T24 cells and induced Wnt signaling activity to promote the progression of bladder cancer. Similarly, the transplanted tumor nude mouse model demonstrated that silencing GTF2IRD2P1 strengthens the progression of bladder cancer by targeting the Wnt signaling pathway.

Long non-coding RNA LINC01207 promotes cell proliferation and migration but suppresses apoptosis and autophagy in oral squamous cell carcinoma by the microRNA-1301-3p/lactate dehydrogenase isoform A axis

Long noncoding RNAs (lncRNAs) have been reported to participate in the progression of various cancers, including oral squamous cell carcinoma (OSCC). This study aims to find out whether lncRNA LINC01207 regulates the progression of OSCC. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to evaluate gene expression in OSCC cells and tissues. Cell viability, proliferation, migration, apoptosis, and autophagy were detected using Cell Counting Kit-8 (CCK-8), colony formation, Transwell assays, flow cytometry, and western blot analysis. Luciferase reporter and RNA immunoprecipitation (RIP) assays were conducted to assess the interactions among genes. We found that LINC01207 was overexpressed in OSCC cells and tissues. LINC01207 silencing inhibited OSCC cell proliferation and migration but promoted apoptosis and autophagy, and LINC01207 overexpression had an opposite result. LINC01207 interacted with microRNA-1301-3p (miR-1301-3p) while lactate dehydrogenase isoform A (LHDA) was targeted by miR1301-3p. Effects caused by LINC01207 downregulation on OSCC cells were reversed by overexpression of LDHA. Overall, LINC01207 promotes OSCC progression via the miR-1301-3p/LDHA axis

Pseudogene Transcripts in Head and Neck Cancer: Literature Review and In Silico Analysis

Once considered nonfunctional, pseudogene transcripts are now known to provide valuable information for cancer susceptibility, including head and neck cancer (HNC), a serious health problem worldwide, with about 50% unimproved overall survival over the last decades. The present review focuses on the role of pseudogene transcripts involved in HNC risk and prognosis. We combined current literature and in silico analyses from The Cancer Genome Atlas (TCGA) database to identify the most deregulated pseudogene transcripts in HNC and their genetic variations. We then built a co-expression network and performed gene ontology enrichment analysis to better understand the pseudogenes’ interactions and pathways in HNC. In the literature, few pseudogenes have been studied in HNC. Our in silico analysis identified 370 pseudogene transcripts associated with HNC, where SPATA31D5P, HERC2P3, SPATA31C2, MAGEB6P1, SLC25A51P1, BAGE2, DNM1P47, SPATA31C1, ZNF733P and OR2W5 were found to be the most deregulated and presented several genetic alterations. NBPF25P, HSP90AB2P, ZNF658B and DPY19L2P3 pseudogenes were predicted to interact with 12 genes known to participate in HNC, DNM1P47 was predicted to interact with the TP53 gene, and HLA-H pseudogene was predicted to interact with HLA-A and HLA-B genes. The identified pseudogenes were associated with cancer biology pathways involving cell communication, response to stress, cell death, regulation of the immune system, regulation of gene expression, and Wnt signaling. Finally, we assessed the prognostic values of the pseudogenes with the Kaplan–Meier Plotter database, and found that expression of SPATA31D5P, SPATA31C2, BAGE2, SPATA31C1, ZNF733P and OR2W5 pseudogenes were associated with patients’ survival. Due to pseudogene transcripts’ potential for cancer diagnosis, progression, and as therapeutic targets, our study can guide new research to HNC understanding and development of new target therapies.

Exploring the long noncoding RNAs-based biomarkers and pathogenesis of malignant transformation from dysplasia to oral squamous cell carcinoma by bioinformatics method

Long noncoding RNAs (lncRNAs) play an important role in many biological processes and carcinogenesis. We aimed to explore lncRNA-based pathogenesis, diagnostic biomarkers, and predictive factors of malignant transformation from dysplasia to oral squamous cell carcinoma (OSCC). Microarray data of GSE30784 consisting of 167 OSCC, 17 dysplasia, and 45 normal oral tissues were downloaded from the GEO database. The differentially expressed genes (DEGs) and lncRNAs between the three samples were identified using R, followed by lncRNA-mRNA coexpression and coregulation network analysis for the prediction of lncRNA target genes. Gene Ontology and Kyoto encydopedia of gene and genomes pathway analysis were performed to further characterize potential interactions. A total of 4462 DEGs and 76 differentially expressed lncRNAs were screened between the three groups, and 200 DEGs and only double homeobox A pseudogene 10 (DUXAP10) were screened among the three groups. A total of 1662 interactions of 46 lncRNAs and their coexpressed target genes were predicted, and 38 pairs of lncRNA-lncRNA coregulated 843 target genes. The coregulated target genes significantly enriched in antigen adaptive immune response, activation of phagocytosis receptor signaling, mast granule NF-κB inflammation, etc. Overall, lncRNAs were differentially expressed in OSCC and dysplasia. The target genes might play an important role in the carcinogenesis and development of OSCC. These results improve our understanding regarding the lncRNA-based pathogenesis and identify some potential targets for early diagnosis of malignant transformation from dysplasia to OSCC.

A Combined Prediction Model for Lymph Node Metastasis Based on a Molecular Panel and Clinicopathological Factors in Oral Squamous Cell Carcinoma

Objective

Lymph node metastasis is the most important factor influencing the prognosis of oral squamous cell carcinoma (OSCC) patients. However, there is no proper method for predicting lymph node metastasis. This study aimed to construct and validate a preoperative prediction model for lymph node metastasis and guide personalized neck management based on the gene expression profile and clinicopathological parameters of OSCC.

Methods

Based on a previous study of related genes in OSCC, the mRNA expression of candidate genes was evaluated by real-time PCR in OSCC specimens. In this retrospective study, the gene expression profile and clinicopathological parameters of 112 OSCC patients were combined to construct the best prediction model for lymph node metastasis of OSCC. The model was validated with 95 OSCC samples in this study. Logistic regression analysis was used. The area under the curve (AUC) ultimately determined the diagnostic value of the prediction model.

Results

The two genes CDKN2A + PLAU were closely related to lymph node metastasis of oral squamous cell carcinoma. The model with the combination of CDKN2A, PLAU, T stage and pathological grade was the best in predicting lymph node metastasis (AUC = 0.807, 95% CI: 0.713-0.881, P=0.0001). The prediction model had a specificity of 96% and sensitivity of 72.73% for stage T1 and T2 OSCC (AUC = 0.855, 95% CI: 0.697-0.949, P=0.0001).

Conclusions

High expression of CDKN2A and PLAU was associated with lymph node metastasis in OSCC. The prediction model including CDKN2A, PLAU, T stage and pathological grade can be used as the best diagnostic model for lymph node metastasis in OSCC.

FTH1 Pseudogenes in Cancer and Cell Metabolism

Ferritin, the principal intracellular iron-storage protein localized in the cytoplasm, nucleus, and mitochondria, plays a major role in iron metabolism. The encoding ferritin genes are members of a multigene family that includes some pseudogenes. Even though pseudogenes have been initially considered as relics of ancient genes or junk DNA devoid of function, their role in controlling gene expression in normal and transformed cells has recently been re-evaluated. Numerous studies have revealed that some pseudogenes compete with their parental gene for binding to the microRNAs (miRNAs), while others generate small interference RNAs (siRNAs) to decrease functional gene expression, and still others encode functional mutated proteins. Consequently, pseudogenes can be considered as actual master regulators of numerous biological processes. Here, we provide a detailed classification and description of the structural features of the ferritin pseudogenes known to date and review the recent evidence on their mutual interrelation within the complex regulatory network of the ferritin gene family.

Long non-coding RNA DNM3OS/miR-204-5p/HIP1 axis modulates oral cancer cell viability and migration

BACKGROUND

Non-coding RNAs play a critical role in the occurrence and development of oral cancer. The present study is aimed to identify long non-coding RNA (lncRNA) that might be novel effective targets for the treatments of oral cancer and the underlying mechanism.

METHODS

The microarray profiling and RNA-sequencing analysis were performed to identify lncRNAs related to oral cancer development, and lncRNA DNM3OS was selected. DNM3OS knockdown was generated in cancer cell lines, and the specific effects of DNM3OS knockdown on cell phenotype were examined. DNM3OS targeted miRNA and miRNA targeted downstream mRNA were selected, the predicted bindings were verified, and the specific effects of miRNA on oral cancer cells were examined. Finally, the dynamic effects of DNM3OS and miRNA on target mRNA expression and oral cancer cell phenotype were examined.

RESULTS

DNM3OS was upregulated in oral cancer tissues and cells. DNM3OS knockdown in CAL27 and SCC-9 cells inhibited cell viability and migration. DNM3OS targeted miR-204-5p to inhibit miR-204-5p expression. miR-204-5p overexpression suppressed oral cancer cell aggressiveness. miR-204-5p targeted HIP1 to inhibit HIP1 expression. HIP1 knockdown inhibited oral cancer cell viability and migration. The effects of DNM3OS knockdown were significantly reversed by miR-204-5p inhibition. Within oral carcinoma tissue samples, expression of DNM3OS and HIP1 was increased whereas the miR-204-5p expression was downregulated; miR-204-5p had a negative correlation with DNM3OS and HIP1, respectively, while DNM3OS and HIP1 were positively correlated with each other.

CONCLUSION

Long non-coding RNA DNM3OS, miR-204-5p, and HIP1 form an axis that modulates oral cancer cell viability and migration.

lncRNA MCM3AP-AS1 promotes the development of oral squamous cell carcinoma by inhibiting miR-363-5p

The aim of the present study was to study the mechanism of the long non-coding (lnc)RNA MCM3AP-AS1 in the development of oral squamous cell carcinoma (OSCC). Patients with OSCC (n=36) volunteered to join the study, and their tumor/normal tissues were collected. MCM3AP-AS1 and microRNA (miR)-363-5p expression in tissues and cells was determined by reverse transcription-quantitative (RT-q)PCR. Following transfection, a CCK-8 assay and Transwell experiments were conducted to explore the effects of MCM3AP-AS1 on OSCC cell proliferation, migration and invasion. The interaction between MCM3AP-AS1 and miR-363-5p was detected by luciferase reporter gene assay. RT-qPCR analysis demonstrated significantly higher MCM3AP-AS1 expression in tumor tissues or OSCC cells compared with normal tissues or human oral keratinocytes cells (P<0.05). A high MCM3AP-AS1 level was associated with poor prognosis in OSCC patients (P<0.05 or P<0.01). Compared to the small interfering (si)-negative control (NC) group, OSCC cells of si-MCM3AP-AS1 group exhibited markedly lower optical density (at 450 nm) value and relative migration and invasion (P<0.05). miR-363-5p was directly inhibited by MCM3AP-AS1. OSCC cells of si-MCM3AP-AS1 + inhibitor-NC group exhibited clearly lower relative proliferation, migration and invasion compared with cells of si-NC + inhibitor-NC group and si-MCM3AP-AS1 + miR-363-5p inhibitor group (P<0.05). MCM3AP-AS1 promoted OSCC cells proliferation, migration and invasion by inhibiting miR-363-5p.

Long non-coding RNA TP73-AS1 promotes TFAP2B-mediated proliferation, metastasis and invasion in retinoblastoma via decoying of miRNA-874-3p

Retinoblastoma (RB) is one of the most common ophthalmic tumors, and most of the patients have been identified as advanced at the time of diagnosis, which is directly related to high mortality. Recent studies showed that long noncoding RNA (lncRNA) and miRNAs play key roles in the development、progression、or treatment of cancer, such as RB. However, the role of lncRNA -TP73-AS1 in RB remains unclear. In this study, we performed functional and mechanistic investigation of miRNA-874-3p-TP73-AS1 interaction in RB. The experiments results revealed that miRNA-874-3p had anti-oncogenic functions in RB. Moreover, the bioinformatics analysis shown that TP73-AS1 could bind to miRNA-874-3p. TP73-AS1 was inversely correlated with miRNA-874-3p expression. Furthermore, studies confirmed that TP73-AS1 negatively regulated miRNA-874-3p expression via functioning as a ceRNA. In a word, our results suggest that the TP73-AS1/ miRNA-874-3p / TFAP2B (transcription factor activating enhancer-binding protein 2B) pathway contributes to the progression of RB, which may provide novel insights into the function of lncRNA-driven retinoblastogenesis. Graphical abstract.

MIR4435-2HG regulates cancer cell behaviors in oral squamous cell carcinoma cell growth by upregulating TGF-β1

MIR4435-2HG has been characterized as an oncogenic lncRNA in several types of cancer, while its role in oral squamous cell carcinoma (OSCC, a major subtype of oral cancer) has not been characterized. We explored the functionality of MIR4435-2HG in OSCC and investigated its interactions with TGF-β1. Blood samples were extracted from OSCC patients (n = 44) and healthy volunteers (n = 38), RT-qPCR, CCK-8, Transwell assays and western blot were performed in this study. The results showed that levels of MIR4435-2HG and TGF-β1 in plasma were upregulated in OSCC. Across OSCC plasma samples, TGF-β1 and MIR4435-2HG were significantly and positively correlated. Overexpression of MIR4435-2HG resulted in upregulated TGF-β1 expression, while exogenous TGF-β1 treatment had no effect on the expression of MIR4435-2HG. Overexpression of MIR4435-2HG and exogenous TGF-β1 treatment led to promoted, while TGF-β inhibitor led to inhibited migration, proliferation and invasion of cancer cells. Moreover, TGF-β inhibitor led to reduced effects of overexpressing MIR4435-2HG. Therefore, MIR4435-2HG regulates the behaviors of OSCC cells by promoting the expression of TGF-β1.

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.

Long Non-Coding RNA Expression Profile Associated with Malignant Progression of Oral Submucous Fibrosis

Oral submucous fibrosis (OSF) as one of the premalignant disorders endures a series of histopathological stages to invasive oral squamous cell carcinoma (OSCC) eventually. However, the role of long non-coding RNA (lncRNA) expression in OSF malignant progression still remains poorly understood. Through RNA-sequencing normal mucous, OSF and OSCC tissues, we found 687 lncRNA transcripts significantly and differentially expressed during OSF progression, including 231 upregulated lncRNAs and 456 downregulated lncRNAs, indicating that lncRNAs are involved in the regulation of different stages of OSF development. Further functional enrichment analysis showed these differentially expressed lncRNAs participated in inflammation signaling, Wnt signaling, angiogenesis, CCKR signaling, integrin signaling, PDGF signaling, p53 signaling, and EGF receptor (EGFR) signaling pathways, which contribute to inflammatory and fibroelastic pathogenetic changes of OSF and further malignant progression. Five novel lncRNAs were differentially expressed during OSF progression with varied expression levels, indicating the importance of these lncRNAs in OSF malignant development. Moreover, some lncRNAs have been previously identified to be associated with OSCC pathogenesis, including HCG22, RP11-397A16.1, LINC00271, CTD-3179P9.1, and ZNF667-AS1. Thus, our study firstly comprehensively elucidated lncRNAs expression profile of malignant procession from OSF premalignant lesion to OSCC, which will enlighten our understanding of the importance of lncRNA involved in OSF malignant development.

Suppression of the long non-coding RNA MALAT-1 impairs the growth and migration of human tongue squamous cell carcinoma SCC4 cells

INTRODUCTION

Aberrant expression of long non-coding RNAs (lncRNAs) is associated with metastasis and poor prognosis in patients with various cancer types. However, few studies have assessed lncRNAs in oral squamous cell carcinoma (OSCC). This study aimed to investigate the expression and impact of lncRNAs in OSCC.

MATERIAL AND METHODS

Real-time PCR analysis was used to examine the expression of four lncRNAs, MALAT-1, UCA1, BC200 and SRA, in 14 OSCC and adjacent normal tissue pairs. The impact of MALAT-1 suppression by siRNA on the proliferation, apoptosis, anchorage-independent growth and migration of the human tongue carcinoma cell line SSC4 was also determined.

RESULTS

MALAT-1 levels were significantly higher in the OSCC tissue than in the normal tissues (p < 0.004); no significant differences in UCA1, BC200 or SRA RNA levels were observed. Knockdown of MALAT-1 by siRNA significantly suppressed proliferation of SSC4 cells (p < 0.004) and enhanced their apoptosis (p < 0.001). In addition, siRNA-mediated suppression of MALAT-1 inhibited SSC4 cell colony formation (p < 0.001) and migration (p < 0.004).

CONCLUSIONS

Elevated expression of MALAT-1 in OSCC may play a role in tumorigenesis and/or metastasis. Further studies are necessary to identify the mechanism by which MALAT-1 influences SCC4 growth and migration and validate its increased expression in OSCC patients.

Long noncoding RNA MORT overexpression inhibits cancer cell proliferation in oral squamous cell carcinoma by downregulating ROCK1

Long noncoding RNA (lncRNA) mortal obligate RNA transcript (MORT) was downregulated many types of cancer tissues, while its functionality in cancer biology is unclear. In the present study, we systemically investigated the involvement of lncRNA MORT in oral squamous cell carcinoma (OSCC). In the present study, we found that lncRNA MORT was downregulated, while rho-associated coiled-coil containing protein kinase 1 (ROCK1) messenger RNA was upregulated in cancer tissues than in adjacent healthy tissues of OSCC patients. In addition, expression levels of lncRNA MORT and ROCK1 were inversely correlated in both tumor tissues and healthy tissues. Follow-up study showed that low MORT level was significantly correlated with poor survival. Overexpression of lncRNA MORT inhibited the proliferation of OSCC cells and downregulated ROCK1. ROCK1 overexpression led to significantly promoted cell proliferation but showed no significant effect on MORT expression. In addition, ROCK1 overexpression attenuated the inhibitory effects of lncRNA MORT overexpression on the proliferation of OSCC cells. Therefore, lncRNA MORT overexpression may inhibit cancer cell proliferation in OSCC cells by downregulating ROCK1.

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.

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.

Transcriptomic analysis reveals key lncRNAs associated with ribosomal biogenesis and epidermis differentiation in head and neck squamous cell carcinoma

OBJECTIVE

In this study, we aimed to expand current knowledge of head and neck squamous cell carcinoma (HNSCC)-associated long noncoding RNAs (lncRNAs), and to discover potential lncRNA prognostic biomarkers for HNSCC based on next-generation RNA-seq.

METHODS

RNA-seq data of 546 samples from patients with HNSCC were downloaded from The Cancer Genome Atlas (TCGA), including 43 paired samples of tumor tissue and adjacent normal tissue. An integrated analysis incorporating differential expression, weighted gene co-expression networks, functional enrichment, clinical parameters, and survival analysis was conducted to discover HNSCC-associated lncRNAs. The function of CYTOR was verified by cell-based experiments. To further identify lncRNAs with prognostic significance, a multivariate Cox proportional hazard regression analysis was performed. The identified lncRNAs were validated with an independent cohort using clinical feature relevance analysis and multivariate Cox regression analysis.

RESULTS

We identified nine HNSCC-relevant lncRNAs likely to play pivotal roles in HNSCC onset and development. By functional enrichment analysis, we revealed that CYTOR might participate in the multistep pathological processes of cancer, such as ribosome biogenesis and maintenance of genomic stability. CYTOR was identified to be positively correlated with lymph node metastasis, and significantly negatively correlated with overall survival (OS) and disease free survival (DFS) of HNSCC patients. Moreover, CYTOR inhibited cell apoptosis following treatment with the chemotherapeutic drug diamminedichloroplatinum (DDP). HCG22, the most dramatically down-regulated lncRNA in tumor tissue, may function in epidermis differentiation. It was also significantly associated with several clinical features of patients with HNSCC, and positively correlated with patient survival. CYTOR and HCG22 maintained their prognostic values independent of several clinical features in multivariate Cox hazards analysis. Notably, validation either based on an independent HNSCC cohort or by laboratory experiments confirmed these findings.

CONCLUSIONS

Our transcriptomic analysis suggested that dysregulation of these HNSCC-associated lncRNAs might be involved in HNSCC oncogenesis and progression. Moreover, CYTOR and HCG22 were confirmed as two independent prognostic factors for HNSCC patient survival, providing new insights into the roles of these lncRNAs in HNSCC as well as clinical applications.

Identification of 4-lncRNA prognostic signature in head and neck squamous cell carcinoma

Deregulated long noncoding RNAs (lncRNA) have been critically implicated in tumorigenesis and serve as novel diagnostic and prognostic biomarkers. Here we sought to develop a prognostic lncRNA signature in patients with head and neck squamous cell carcinoma (HNSCC). Original RNA-seq data of 499 HNSCC samples were retrieved from The Cancer Genome Atlas database, which was randomly divided into training and testing set. Univariate Cox regression survival analysis, robust likelihood-based survival model and random sampling iterations were applied to identify prognostic lncRNA candidates in the training cohort. A prognostic risk score was developed based on the Cox coefficient of four individual lncRNA imputed as follows: (0.14546 × expression level of RP11-366H4.1) + (0.27106 × expression level of LINC01123) + (0.54316 × expression level of RP11-110I1.14) + (-0.48794 × expression level of CTD-2506J14.1). Kaplan-Meier analysis revealed that patients with high-risk score had significantly reduced overall survival as compared with those with low-risk score when patients in training, testing, and validation cohorts were stratified into high- or low-risk subgroups. Multivariate survival analysis further revealed that this 4-lncRNA signature was a novel and important prognostic factor independent of multiple clinicopathological parameters. Importantly, ROC analyses indicated that predictive accuracy and sensitivity of this 4-lncRNA signature outperformed those previously well-established prognostic factors. Noticeably, prognostic score based on quantification of these 4-lncRNA via qRT-PCR in another independent HNSCC cohort robustly stratified patients into subgroups with high or low survival. Taken together, we developed a robust 4-lncRNA prognostic signature for HNSCC that might provide a novel powerful prognostic biomarker for precision oncology.

Long non-coding RNA FTH1P3 regulated metastasis and invasion of esophageal squamous cell carcinoma through SP1/NF-kB pathway

AIMS：: Recent research showed that Long non-protein coding RNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) plays a crucial role in the course of tumor formation. The present study was aimed to explore its role in esophageal squamous cell carcinoma (ESCC).

MAIN METHODS

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to examine the expression levels of FTH1P3, mRNA SP1 and NF-kB in ESCC samples and cell lines. The impact of FTH1P3 knockdown was evaluated by WST-1 assays, colony formation assays, scratch wound assays, migration and invasion assays.

KEY FINDINGS

FTH1P3 was significantly upregulated in ESCC tissues and cells (P < 0.001). Knockdown of FTH1P3 notably decreased the proliferation, migration, and invasion capacity of ESCC cells. Silencing of FTH1P3 decreased the expression of specificity protein 1 (Sp1) and NF-kB (p65) in EC9706 and EC1.

SIGNIFICANCE

FTH1P3 plays a crucial role in ESCC tumorigenesis, and can be used as a potential therapeutic target for ESCC.

Transcriptome analysis reveals differentially expressed lncRNAs between oral squamous cell carcinoma and healthy oral mucosa

Oral cavity and oropharyngeal squamous cell carcinoma (OSCC) is a major cancer type in the head and neck region. To better understand the roles long non-coding RNA (lncRNA) play in OSCC carcinogenesis, we compared the expression levels of 3,054 probe sets for lncRNAs between 167 OSCCs and 45 healthy oral mucosa using an Affymetrix HG U133 plus 2.0 array dataset. We found 658 lncRNA transcripts (790 probe sets) to be significantly differentially expressed using a criteria of FDR < 0.01, with 36 of them (39 probe sets) showing more than a 2-fold change. We further validated the top differentially expressed lncRNAs in three independent datasets from Gene Expression Omnibus (GEO) repository: GSE42743, GSE9844, and GSE6791. Fourteen lncRNAs (15 probe sets) were validated in all three datasets using the criteria FDR < 0.01: LOC441178, C5orf66-AS1, HCG22, FLG-AS1, CCL14/CCL15-CCL14, LOC100506990, TRIP10, PCBP1-AS1, LINC01315, LINC00478, COX10-AS1/LOC100506974, MLLT4-AS1, MIR31HG, and DUXAP10/LINC01296. Three lncRNAs in the validated list which showed the highest fold change (LOC441178, HCG22 and C5orf66-AS1) were verified by quantitative RT-PCR in a subset of 20 OSCCs and 10 control samples. In silico prediction of their functional role has given us directions for further investigation.

Current research on head and neck cancer-associated long noncoding RNAs

Head and neck cancers (HNC) are one of the ten leading cancers worldwide, including a range of malignant tumors arising from the upper neck. Due to the complex mechanisms of HNC and lack of effective biomarkers, the 5-year survival rate of HNC has been low and the mortality rate has been high in recent decades. Long noncoding RNAs (lncRNAs), noncoding RNAs longer than 200 bps, are a focus of current cancer research, closely related to tumor biology. LncRNAs have been revealed to be aberrantly expressed in various types of HNC, and the dysregulated lncRNAs participate in HNC progression and induce malignant behavior by modulating gene expression at diverse levels. This review will focus on the functions and molecular mechanisms of dysregulated lncRNAs in HNC tumorigenesis and progression, as well as their diagnostic, therapeutic or prognostic implications in HNC.

lncRNA in HNSCC: challenges and potential

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cause of cancer mortality in the world. Some progress has been made in the therapy of HNSCC, however treatment remains unsatisfactory. Recent studies have shown that different types of long non-coding RNAs (lncRNAs) are dysregulated in HNSCC and correlate with tumor progression, lymph node metastasis, clinical stage and poor prognosis. lncRNAs are a class of functional RNA molecules that can not be translated into proteins but can modulate the activity of transcription factors or regulate changes in chromatin structure. The lncRNAs might have potential of biomarker in HNSCC diagnosis, prognosis, prediction and targeted treatment. In this review we describe the potential role of lncRNAs as new biomarkers and discuss their features including source of origin, extraction methods, stability, detection methods and data normalization and potential function as biomarkers in HNSCC.

Long non-coding RNA FTH1P3 facilitates uveal melanoma cell growth and invasion through miR-224-5p

Growing evidences indicated that Long noncoding RNAs (lncRNAs) played important roles in tumor initiation and progression. However, the function and mechnism of lncRNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) remain unknown in uveal melanoma. We showed that the expression level of FTH1P3 was upregulated in uveal melanoma cell lines and tissues. Elevated expression of FTH1P3 promoted uveal melanoma cell proliferation, cell cycle and migration. Moreover, we found that FTH1P3 was a direct target gene of miR-224-5p in uveal melanoma cell. Overexpression of FTH1P3 suppressed miR-224-5p expression and promoted the expression of Rac1 and Fizzled 5, which were the direct target genes of miR-224-5p. Furthermore, we showed that miR-224-5p expression level was downregulated in uveal melanoma cell lines and tissues. FTH1P3 expression was inversely correlated with the miR-224-5p expression in uveal melanoma tissues. Ectopic expression of miR-224-5p decreased uveal melanoma cell proliferation, cell cycle and migration. Elevated expression of FTH1P3 enhanced uveal melanoma cell proliferation and migration by inhibiting miR-224-5p expression. These results suggest that lncRNA FTH1P3 plays a crucial role in uveal melanoma. Investigation of the underlying mechanism may be a target for the treatment of uveal melanoma.

The lncRNA PDIA3P Interacts with miR-185-5p to Modulate Oral Squamous Cell Carcinoma Progression by Targeting Cyclin D2

Long noncoding RNAs (lncRNAs) are emerging as important regulators during tumorigenesis by serving as competing endogenous RNAs (ceRNAs). In this study, the qRT-PCR results indicated that the lncRNA protein disulfide isomerase family A member 3 pseudogene 1 (PDIA3P) was overexpressed in oral squamous cell carcinoma (OSCC) and decreased the survival rate of OSCC patients. CCK-8 and clonal colony formation assays were used to detect the effects of PDIA3P on proliferation. Results revealed that silencing PDIA3P by small interfering RNA (siRNA) inhibited OSCC cell proliferation and repressed tumor growth and reduced the expression of proliferation antigen Ki-67 in vivo. Furthermore, the interaction between PDIA3P and miRNAs was then analyzed by qRT-PCR and luciferase reporter gene assay. We found that PDIA3P negatively regulated miR-185-5p in OSCC cells. Simultaneously, we found that silencing PDIA3P by siRNA suppressed proliferation via miR-185-5p in OSCC cells. Moreover, silencing PDIA3P by siRNA inhibited CCND2 protein (no influence on mRNA levels) expression via miR-185-5p in OSCC cells, and CCND2 facilitated cell proliferation of SCC4 and SCC15 cells induced by sh-PDIA3P#1. Therefore, our study demonstrated that PDIA3P may be a therapeutic target for the treatment of OSCC.

Biological role of long non-coding RNA in head and neck cancers

Head and neck squamous cell carcinoma (HNSCC) are one of the worst prognosis cancers with high mortality of patients. The treatment strategy is primarily based on surgery and radiotherapy but chemotherapy is also used. Every year the knowledge concerning HNSCC biology is updated with new elements such as the recent discovered molecules - long non-coding RNAs. Long non-coding RNAs are involved in regulatory processes in the cells. It has been revealed that the expression levels of lncRNAs are disturbed in tumor cells what results in the acquisition of their specific phenotype. lncRNAs influence cell growth, cell cycle, cell phenotype, migration and invasion ability as well as apoptosis. Development of the lncRNA panel characteristic for HNSCC and validation of specific lncRNA functions are yet to be elucidated. In this work, we collected available data concerning lncRNAs in HNSCC and characterized their biological role. We believe that the tumor examination, in the context of lncRNA expression, may lead to understanding complex biology of the cancer and improve therapeutic methods in the future.

Complex integrated analysis of lncRNAs-miRNAs-mRNAs in oral squamous cell carcinoma

OBJECTIVES

This study aims to reveal regulatory network of lncRNAs-miRNAs-mRNAs in oral squamous cell carcinoma (OSCC) through gene expression data.

MATERIAL AND METHODS

Differentially expressed lncRNAs, miRNAs and mRNAs (cut-off: False discovery rate (FDR)<0.05 and |fold change|>1.5) were unveiled by package edgeR of R. Cox regression analysis was performed to screen prognostic factors in OSCC related with overall survival (OS) and relapse-free survival (RFS). Protein-protein interaction (PPI) network was constructed for differentially expressed mRNAs using BioGRID, HPRD and DIP. Key hub genes were identified from top 100 differentially expressed mRNAs ranked by betweenness centrality using recursive feature elimination. LncRNA-miRNA and miRNA-mRNA regulatory network were constructed and combined into ceRNAs regulatory network. Gene ontology biological terms and Kyoto Encyclopedia of Genes and Genomes pathways were identified using Fisher's exact test.

RESULTS

A total of 929 differentially expressed mRNAs, 23 differentially expressed lncRNAs and 29 differentially expressed miRNAs were identified. 59 mRNAs, 6 miRNAs (hsa-mir-133a-1, hsa-mir-1-2, hsa-mir-486, hsa-mir-135b, hsa-mir-196b, hsa-mir-193b) and 6 lncRNAs (C10orf91, C2orf48, SFTA1P, FLJ41941,PART1,TTTY14) were related with OS; and 52 mRNAs, 4 miRNAs (hsa-mir-133a-1, hsa-mir-135b, hsa-mir-196b, hsa-mir-193b) and 2 lncRNAs (PART1, TTTY14) were associated with RFS. A support vector machine (SVM) classifier containing 37 key hub genes was obtained. A ceRNA regulatory network containing 417 nodes and 696 edges was constructed. ECM-receptor interaction, cytokine-cytokine receptor interaction, focal adhesion, arachidonic acid metabolism, and p53 signaling pathway were significantly enriched in the network.

CONCLUSION

These findings uncover the pathogenesis of OSCC and might provide potential therapeutic targets.

Long intergenic non-coding RNA 668 regulates VEGFA signaling through inhibition of miR-297 in oral squamous cell carcinoma

Recently, long noncoding RNAs (lncRNAs) have been reported to have crucial regulatory efficiency in human cancer biology. Long intergenic non-coding RNA 668 (LINC00668) was regarded as an oncogene in multiple cancers. However, the underlying molecular mechanism of LINC00668 in oral squamous cell carcinoma (OSCC) has not been studied. In this study, we first demonstrated that LINC00668 expression was up-regulated, which was correlated with tumor progression, and miR-297 down-regulated in OSCC tissues and cells. Importantly, LINC00668 expression was negatively correlated with miR-297 expression in OSCC tissues. Loss-of-function of LINC00668 revealed that LINC00668 functioned as a ceRNA for miR-297 to facilitate VEGFA expression, promoting OSCC progression. Furthermore, LINC00668 knockdown suppressed tumor growth and reduced the expression of proliferation antigen ki-67 in vivo. Finally, we confirmed that LINC00668 promoted OSCC activity through VEGFA signaling. In conclusion, these results suggest that LINC00668 promotes OSCC tumorigenesis via miR-297/VEGFA axis, which may provide a new target for the diagnosis and therapy of OSCC disease.

Epigenetics of oropharyngeal squamous cell carcinoma: opportunities for novel chemotherapeutic targets

Epigenetic modifications are heritable changes in gene expression that do not directly alter DNA sequence. These modifications include DNA methylation, histone post-translational modifications, small and non-coding RNAs. Alterations in epigenetic profiles cause deregulation of fundamental gene expression pathways associated with carcinogenesis. The role of epigenetics in oropharyngeal squamous cell carcinoma (OPSCC) has recently been recognized, with implications for novel biomarkers, molecular diagnostics and chemotherapeutics. In this review, important epigenetic pathways in human papillomavirus (HPV) positive and negative OPSCC are summarized, as well as the potential clinical utility of this knowledge.This material has never been published and is not currently under evaluation in any other peer-reviewed publication.

Aberrant DNA hypermethylation-silenced SOX21-AS1 gene expression and its clinical importance in oral cancer

Background

Long noncoding RNAs (lncRNAs) are more than 200 nucleotides in length and lack transcriptional ability. The biological function of lncRNAs in oral squamous cell carcinoma (OSCC) remains unclear. The aim of this study was to identify the dysfunction of lncRNA in OSCC.

Results

We analyzed the transcriptome profiles of human OSCC tissues and paired adjacent normal tissues from two patients through a next-generation sequencing approach. A total of 14 lncRNAs were upregulated (fold change ≥3) and 13 were downregulated (fold change ≤−3) in OSCC tissues compared with the adjacent normal tissues. SOX21-AS1 was subjected to further analysis, revealing that the expression levels of SOX21-AS1 significantly decreased in OSCC compared with the adjacent normal tissue. The promoter activity of SOX21-AS1 was obviously suppressed by in vitro methylation. The DNA methylation status of the SOX21-AS1 promoter was analyzed using combined bisulfite restriction analysis, revealing that the aberrant promoter hypermethylation of SOX21-AS1 was observed frequently in OSCC tissues. The effects of SOX21-AS1 on cell proliferation and invasion were examined through transient transfection. Our data showed that SOX21-AS1 could significantly suppress oral cancer cell growth and invasion. Furthermore, the low expression level of SOX21-AS1 was significantly correlated with an advanced stage (P = 0.047), large tumor size (P = 0.033), and poor disease-specific survival in OSCC patients (P = 0.002).

Conclusions

SOX21-AS1 was identified as susceptible dysfunction correlated with promoter hypermethylation in OSCC. Low SOX21-AS1 expression may be an adverse prognostic biomarker for OSCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0291-5) contains supplementary material, which is available to authorized users.

The emerging role of long noncoding RNAs in oral cancer

Although less than 3% of the genome encodes proteins, at least 75% of the genome is transcribed into RNAs with no protein-coding potential (noncoding RNAs [ncRNAs]). On the basis of their size and the arbitrary 200 nucleotides cutoff, ncRNAs are classified into long ncRNAs (lncRNAs) or small ncRNAs (including microRNAs). Over the last few years, the role of microRNAs in oral squamous cells carcinoma (OSCC) has been extensively addressed, but the possible role of lncRNAs in OSCC remains unclear. We aimed to explore and discuss the potential role of lncRNAs in OSCC. The detection of lncRNAs in saliva holds promise not only as a noninvasive diagnostic tool in OSCC but also in the early detection of oral cancer recurrence. lncRNAs are promising future therapeutic targets in the OSCC scenario, and research in this field may expand greatly in the next decade.

Expression profiles of long noncoding RNAs in cutaneous squamous cell carcinoma

BACKGROUND

Despite there being over 35,000 different long noncoding RNA (lncRNA) sequences described little is known regarding their molecular-pathological role in cutaneous squamous cell carcinoma (cSCC).

MATERIALS & METHODS

In this pilot study, lncRNA and mRNA expression profiles were determined in cSCC and control (n = 6) by an Arraystar human lncRNA Microarray. Kyoto Encyclopedia of Genes and Genomes pathway enrichment and gene ontology analysis of mRNAs was performed.

RESULTS

Analysis of differential expression revealed 1516 upregulated lncRNAs and 2586 downregulated lncRNAs in cSCC compared with controls. Data analysis identified known oncogenic lncRNAs, such as the HOX transcript antisense RNA HOTAIR, among the differentially expressed lncRNA sequences. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that focal adhesion, extracellular matrix and the oncogenic phosphatidylinositol 3'-kinase-Akt signaling pathway had the highest enrichment scores.

CONCLUSION

This study provides the first evidence for differential expression of lncRNA in cSCC and serves as a template for further, larger functional in-depth analyses regarding cSCC molecular lncRNAs.

FTH1P3, a Novel H-Ferritin Pseudogene Transcriptionally Active, Is Ubiquitously Expressed and Regulated during Cell Differentiation

Ferritin, the major iron storage protein, performs its essential functions in the cytoplasm, nucleus and mitochondria. The variable assembly of 24 subunits of the Heavy (H) and Light (L) type composes the cytoplasmic molecule. In humans, two distinct genes code these subunits, both belonging to complex multigene families. Until now, one H gene has been identified with the coding sequence interrupted by three introns and more than 20 intronless copies widely dispersed on different chromosomes. Two of the intronless genes are actively transcribed in a tissue-specific manner. Herein, we report that FTH1P3, another intronless pseudogene, is transcribed. FTH1P3 transcript was detected in several cell lines and tissues, suggesting that its transcription is ubiquitary, as it happens for the parental ferritin H gene. Moreover, FTH1P3 expression is positively regulated during the cell differentiation process.