Profiling and bioinformatics analyses reveal differential expression of circular RNA in tongue cancer revealed by high-throughput sequencing

In Vitro and In Vivo Analyses Reveal Tumor-Derived Exosome miR-558 Promotes Angiogenesis in Tongue Squamous Cell Carcinoma by Targeting Heparinase

This study aimed to investigate the role of miR-558 in tumor angiogenesis by targeting heparinase (HPSE) in tongue squamous cell carcinoma (TSCC)-derived exosomes. In the present study, the role of exosome miR-558 in angiogenesis in vitro and in vivo was investigated by cell proliferation, migration, tube formation, subcutaneous tumor formation in mice, and in vivo Matrigel plug assay. The target genes of miR-558 were detected by means of dual luciferase assay. It was found that TSCC cells secrete miR-558 into the extracellular environment, with exosome as the carrier. Human umbilical vein endothelial cells (HUVEC) ingested exosomes, which not only increased the expression level of miR-558, but also enhanced their proliferation, migration, and tube formation functions. In vivo Matrigel plug assay demonstrated that TSCC cell-derived exosome miR-558 promoted neovascularization in vivo. Compared with negative control cells, TSCC cells overexpressing miR-558 formed subcutaneous tumors in nude mice, with larger volume, heavier mass, and more vascularization. Dual luciferase assay confirmed that HPSE was the direct target gene regulated by miR-558. HPSE promoted the proliferation, migration, and tube formation of HUVECs, and the knockout of HPSE could downregulate the pro-angiogenic effect of miR-558. In summary, miR-558 in TSCC exosomes promotes the proliferation, migration, and tube formation of HUVECs by targeting HPSE, and enhancing tumor angiogenesis.

RNA-Based Liquid Biopsy in Head and Neck Cancer

Head and neck cancer (HNC) is a prevalent and diverse group of malignancies with substantial morbidity and mortality rates. Early detection and monitoring of HNC are crucial for improving patient outcomes. Liquid biopsy, a non-invasive diagnostic approach, has emerged as a promising tool for cancer detection and monitoring. In this article, we review the application of RNA-based liquid biopsy in HNC. Various types of RNA, including messenger RNA (mRNA), microRNA (miRNA), long non-coding RNA (lncRNA), small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), circular RNA (circRNA) and PIWI-interacting RNA (piRNA), are explored as potential biomarkers in HNC liquid-based diagnostics. The roles of RNAs in HNC diagnosis, metastasis, tumor resistance to radio and chemotherapy, and overall prognosis are discussed. RNA-based liquid biopsy holds great promise for the early detection, prognosis, and personalized treatment of HNC. Further research and validation are necessary to translate these findings into clinical practice and improve patient outcomes.

Expression profile and bioinformatics analysis of circular RNAs in tongue squamous cell carcinoma

OBJECTIVE

This study was designed to identify the role of circRNAs in tongue squamous cell carcinoma (TSCC) and discover novel circRNAs as potential diagnostic or therapeutic targets for TSCC.

RESULTS

The circRNA expression profiles in TSCC were evaluated by high-throughput sequencing in 6 TSCC patients. Our data showed that 69 circRNAs were downregulated and 208 were upregulated significantly (fold change ≥2.0; p < 0.05). GO and KEGG analysis demonstrated that the parental genes of differentially expressed circRNAs were potentially implicated in TSCC pathogenesis. After bioinformatics analysis, 4 circRNAs (hsa_circ_0005035, hsa_circ_0002360, hsa_circ_0066251, and hsa_circ_0003161) were selected and successfully validated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) in 40 patients and 3 TSCC cell lines. The establishment and analysis of the circRNA-miRNA-mRNA network revealed the potential function and mechanism of these candidate circRNAs.

CONCLUSION

Our study provided a comprehensive circRNAs expression profile of TSCC by RNA-seq and discovered 4 novel circRNAs with potential great diagnostic and therapeutic value. These findings provide new insights into the development of potential biomarkers and targets for TSCC treatment.

The expression profiles of circular RNAs and competing endogenous RNA networks in intrahepatic cholangiocarcinoma

Introduction: Intrahepatic cholangiocarcinoma (iCCA) is a heterogeneous entity with diverse etiologies, morphologies, and clinical outcomes, but our knowledge of its epidemiology and carcinogenesis is very limited. Materials and methods: The expression patterns of circRNAs were explored in iCCA tissues and corresponding adjacent normal ones, denoted by (iCCA) and (iCCAP), respectively, using high-throughput sequencing. Results: A total of 117 differential expressed (DE) circRNAs were identified. Based on the parental transcripts of circRNAs, these DE circRNAs were related to several important GO terms and were enriched in important pathways. Two circRNA-mediated ceRNA networks were constructed and many important metabolic pathways related to mRNAs were regulated by DE circRNAs via miRNAs. Conclusion: Our study revealed the DE circRNAs in the iCCA tissues compared with iCCAP ones, suggesting that circRNAs may play crucial roles in the pathogenesis of iCCA.

circFAT1 Promotes Cancer Stemness and Immune Evasion by Promoting STAT3 Activation

Cancer stemness and immune evasion are closely associated, and play critical roles in tumor development and resistance to immunotherapy. However, little is known about the underlying molecular mechanisms that coordinate this association. Here, it is reported that elevated circular RNA FAT1 (circFAT1) in squamous cell carcinoma (SCC) unifies and regulates the positive association between cancer stemness and immune evasion by promoting STAT3 activation. circFAT1 knockdown (KD) reduces tumorsphere formation of SCC cells in vitro and tumor growth in vivo. Bioinformatic analysis reveals that circFAT1 KD impairs the cancer stemness signature and activates tumor cell-intrinsic immunity. Mechanistically, circFAT1 binding to STAT3 in the cytoplasm prevents STAT3 dephosphorylation by SHP1 and promotes STAT3 activation, resulting in inhibition of STAT1-mediated transcription. Moreover, circFAT1 KD significantly enhances PD1 blockade immunotherapy by promoting CD8+ cell infiltration into tumor microenvironment. Taken together, the results demonstrate that circFAT1 is an important regulator of cancer stemness and antitumor immunity.

Research Progress of circRNAs in Head and Neck Cancers

Circular RNAs (circRNAs) are a novel type of non-coding RNAs. Because of their characteristics of a closed loop structure, disease- and tissue-specificity, and high conservation and stability, circRNAs have the potential to be biomarkers for disease diagnosis. Head and neck cancers are one of the most common malignant tumors with high incidence rates globally. Affected patients are often diagnosed at the advanced stage with poor prognosis, owing to the concealment of anatomic sites. The characteristics, functions, and specific mechanisms of circRNAs in head and neck cancers are increasingly being discovered, and they have important clinical significance for the early diagnosis, treatment, and prognosis evaluation of patients with cancer. In this study, the generation, characteristics, and functions of circRNAs, along with their regulatory mechanisms in head and neck cancers have been summarized. We report that circRNAs interact with molecules such as transcription and growth factors to influence specific pathways involved in tumorigenesis. We conclude that circRNAs have an important role to play in the proliferation, invasion, metastasis, energy and substance metabolism, and treatment resistance in cancers.

circSLC8A1 Acts as a Tumor Suppressor in Prostate Cancer via Sponging miR-21

BACKGROUND

There is more and more evidence showed that circRNAs played essentially role in the regulation of various biological processes. The role of circSLC8A1 in prostate cancer (PCa) is yet little known.

METHODS

The CircSLC8A1 expression in human prostate cancer was measured by qRT-PCR. The interplay between the specific circRNA, miRNA, and mRNA was investigated by RT-PCR and luciferase reporter assay. Through transient transfection of siRNA, the impacts of circSLC8A1 on PCa were discussed. Cell cycle evaluation, transwell assay, and CCK-8 assay were employed to determine its biological influences.

RESULTS

In this study, our data revealed that circSLC8A1 was downregulated in PCa tissues and cells. The reduction of circSLC8A1 resulted in the inhibition of cell proliferation and migration. In mechanism, circSLC8A1 exhibited a direct interaction with miR-21 and displayed as a miRNA sponge to inhibit PCa progression. The functional analysis revealed that the circSLC8A1/miR-21 axis may regulate the cell proliferation, angiogenesis, cell migration, epithelial to mesenchymal transition, MAPK signaling pathway, and chemokine signaling pathway.

CONCLUSIONS

CircSLC8A1 functioned as an inhibitor of neoplasm via modulating the miR-21 and might serve as a prospective target for the treatment of PCa.

Hsa_circ_0002162 has a critical role in malignant progression of tongue squamous cell carcinoma through targeting miR-33a-5p

The aim of this study was to explore the effect of hsa_circ_0002162 on regulating cell proliferation, apoptosis, and invasion, and investigate its potential target microRNA (miRNA) in tongue squamous cell carcinoma (TSCC). Hsa_circ_0002162 expression was detected in human TSCC cell lines and human oral keratinocytes (HOK) cell line. Cell proliferation, apoptosis, invasion, and candidate target miRNA expressions were detected in hsa_circ_0002162 knockdown-treated CAL-27 cells and hsa_circ_0002162 overexpression-treated SCC-9 cells. In the rescue experiment, miR-33a-5p knockdown plasmid was transfected into hsa_circ_0002162 knockdown-treated CAL-27 cells, while miR-33a-5p overexpression plasmid was transfected into hsa_circ_0002162 overexpression-treated SCC-9 cells. Subsequently, cell proliferation, apoptosis, and invasion were detected, and then luciferase reporter assay was performed. Hsa_circ_0002162 expression was increased in human TSCC cell lines SCC-9, CAL-27, HSC-4, and SCC-25 compared with HOK. In CAL-27 cells, hsa_circ_0002162 knockdown inhibited cell proliferation and invasion and promoted apoptosis. In SCC-9 cells, hsa_circ_0002162 overexpression enhanced cell proliferation and invasion and suppressed apoptosis. Furthermore, a negative regulation of hsa_circ_0002162 on miR-33a-5p (but not miR-302b-5p and miR-545-5p) was observed. In the rescue experiment, miR-33a-5p knockdown increased cell proliferation and invasion, and decreased apoptosis in hsa_circ_0002162 knockdown-treated CAL-27 cells, whereas miR-33a-5p overexpression decreased cell proliferation and invasion, but increased apoptosis in hsa_circ_0002162 overexpression-treated SCC-9 cells. The luciferase reporter assay showed the direct binding of hsa_circ_0002162 to miR-33a-5p. In conclusion, hsa_circ_0002162 had an important role in malignant progression of TSCC through targeting miR-33a-5p.

Circular RNA circSPATA6 Inhibits the Progression of Oral Squamous Cell Carcinoma Cells by Regulating TRAF6 via miR-182

Background

Oral squamous cell carcinoma (OSCC) has become a widely concerned social problem. Circular RNA spermatogenesis-associated protein 6 (circSPATA6) exhibited low expression in OSCC tissues, yet the regulatory mechanism of circSPATA6 remains vague.

Methods

Levels of circSPATA6, linear SPATA6, microRNA-182 (miR-182), and tumor necrosis factor receptor-associated factor 6 (TRAF6) were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Migration, invasion, cell cycle arrest, and apoptosis were assessed by Wound-healing, Matrigel invasion, and Flow cytometry assays. The binding relationship between miR-182 and circSPATA6 or TRAF6 was predicted by circRNA interactome or DIANA TOOL and then proved by the dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays. TRAF6 protein level was measured by Western blot assay. The biological role of circSPATA6 on OSCC tumor growth was analyzed by xenograft tumor model in vivo. Exosomes were isolated and detected by differential centrifugation and a transmission electron microscope.

Results

CircSPATA6 and TRAF6 were declined, and miR-182 was elevated in OSCC cells. Functionally, circSPATA6 impeded migration and invasion, and facilitated cell cycle arrest and apoptosis of OSCC cells. Mechanistically, circSPATA6 could modulate TRAF6 expression through sponging miR-182. Moreover, circSPATA6 blocked tumor growth in the OSCC mice model. Exosomal circSPATA6 retarded the growth of OSCC cells.

Conclusion

CircSPATA6 curbed migration and invasion, and expedited cell cycle arrest and apoptosis in OSCC cells partly through regulating the miR-182/TRAF6 axis. These findings hinted at an underlying circRNA-targeted therapy for OSCC.

Hsa_circ_0043265 Restrains Cell Proliferation, Migration and Invasion of Tongue Squamous Cell Carcinoma via Targeting the miR-1243/SALL1 Axis

Increasing evidence has displayed critical roles of circular RNAs (circRNAs) in tongue squamous cell carcinoma (TSCC). Hsa_circ_0043265 (circ_0043265) has been identified as a tumor suppressor in various tumors. Nevertheless, the critical roles of circ_0043265 in the initiation and progression of TSCC are yet to be fully elucidated. In our study, RNA and protein expressions were detected via qRT-PCR and Western blot. Cell proliferation, migration and invasion were evaluated via CCK-8 and transwell assays. The interactions between circ_0043265, miR-1243 and SALL1 were analyzed via bioinformatics analyses, RNA pull-down and luciferase assays, respectively. The current study demonstrated that circ_0043265 expression was downmodulated in TSCC tissues and cell lines (SCC25, SCC15, SCC9 and Cal27). Functionally, circ_0043265 overexpression led to an attenuation of cell proliferation, migration and invasion of SCC25 and Cal27 cells. Mechanistically, circ_0043265 acted as a competing endogenous RNA (ceRNA) via competitively sponging miR-1243, and restoration of miR-1243 rescued the inhibitory effects of circ_0043265 on cell proliferation, migration and invasion of SCC25 and Cal27 cells. Finally, it was observed that spalt like transcription factor 1 (SALL1), a potential target of miR-1243, was positively modulated via circ_0043265 in SCC25 and Cal27 cells, and SALL1 knockdown reversed the inhibitory effects of circ_0043265 on SCC25 and Cal27 cells. Collectively, the current study demonstrated that circ_0043265 was downmodulated in TSCC and was identified as a ceRNA that restrained the cell proliferation, migration and invasion of SCC25 and Cal27 cells via modulating the miR-1243/SALL1 axis.

Comprehensive analysis of circular RNA in oral leukoplakia: upregulated circHLA-C as a potential biomarker for diagnosis and prognosis

Background

Emerging evidence indicates that circular RNAs (circRNAs) play an indispensable role in a variety of tumors, yet the function of circRNAs in premalignant lesions is still obscure. Oral leukoplakia (OLK) is one of the most common premalignant lesions of the oral mucosa. Our study aimed to comprehensively investigate whether circRNAs contribute to the occurrence and development of OLK.

Methods

We obtained six pairs of OLK and normal oral mucosal (NOM) tissue samples and subjected them to high-throughput sequencing to detect the expression of circRNA. In total, 26 pairs of NOM and OLK tissues were used for validation. Key circRNAs were selected and further validated by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), ribonuclease (RNase) R digestion, and Sanger sequencing. Visualization analysis of circular human leukocyte antigen-C (circHLA-C) was performed in the UCSC Genome Browser (genome.ucsc.edu). Functional analysis of differentially expressed (DE) circRNAs were processed by Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Furthermore, TargetScan (www.targetscan.org) was applied to predict targeted micro RNAs (miRNAs) and messenger RNAs (mRNAs) of circRNAs and a competing endogenous RNA (ceRNA) network related with identified circRNAs was constructed in Cytoscape (v2.8.0).

Results

Profile data showed that 366 circRNAs were significantly altered in OLK tissues, including 65 upregulated and 301 downregulated circRNA transcripts. Compared with sequencing results, seven selected circRNAs expressed the same changing tendency. The amplest upregulated circRNA in our sequencing data, circHLA-C, was confirmed through back-splice junction sequences by Sanger sequencing after RNase R digestion. Correlation analysis demonstrated that circHLA-C correlated positively with the degree of dysplasia. Furthermore, receiver operating characteristic (ROC) curve analysis indicated that circHLA-C had potential diagnostic value with excellent accuracy and specificity.

Conclusions

According to the literature, we were the first to uncover the expression profiles of circRNAs in OLK. Our research performed a comprehensive bioinformatics analysis of DE circRNAs in OLK and identified circHLA-C as a promising diagnostic biomarker with potential as a therapeutic genetic target for OLK.

Expression Profile of Circular RNAs in Oral Squamous Cell Carcinoma

Background

Circular RNAs (circRNAs) are involved in the pathogenesis of several diseases. Among oral maxillofacial cancers, oral squamous cell carcinoma (OSCC) has the highest incidence. However, the role of circRNAs in OSCC is still not clear. The aim of our study was to evaluate the circRNA expression profile in OSCC and explore further the potential role of circRNAs in the pathogenesis of OSCC.

Methods

CircRNA sequencing was performed in 6 pairs of samples of OSCC and normal oral mucosal tissues. Expression of selected circRNAs was validated by qRT-PCR. GO and KEGG analyses were performed and binding relationships between circRNAs and miRNAs were predicted. The hsa_circ_0001766/miR-877-3p/VEGFA axis was selected to further elucidate its role in OSCC.

Results

We showed that there were 122 differentially expressed (DE) circRNAs. Eight out of 10 selected circRNAs were validated by qRT-PCR. GO and KEGG analyses indicated that the identified DE circRNAs might be involved in the progression of OSCC. Then, after identification by Sanger sequencing and RNase R assay, the upregulated hsa_circ_0001766 was selected to investigate its potential role in OSCC. Bioinformatics analysis showed that hsa_circ_0001766 might act as a competing endogenous RNA (ceRNA) that sponged miR-877-3p to upregulate VEGFA expression. We selected OSCC cell lines SCC9 and SCC25. PCR results showed that the expression of hsa_circ_0001766 and VEGFA was upregulated in SCC9 and SCC25. Subsequently, using western blot, PCR, CCK8, and colony formation assays, we found that knocking down circRNA0001766 inhibited the expression of VEGFA and the proliferation of OSCC cells. Following this, miR-877-3p inhibitor reversed the inhibitory effect of si-hsa_circ_0001766 on expression of VEGFA and proliferation of OSCC cells.

Conclusions

In conclusion, our study revealed the possible role of circRNAs in the pathogenesis of OSCC, and identified the potential role of the hsa_circ_0001766/miR-877-3p/VEGFA axis in OSCC progression.

Exosomal cargoes in OSCC: current findings and potential functions

Oral squamous cell carcinoma (OSCC) is the most prevalent malignancy in head and neck cancer, with high recurrence and mortality. Early diagnosis and efficient therapeutic strategies are vital for the treatment of OSCC patients. Exosomes can be isolated from a broad range of different cell types, implicating them as important factors in the regulation of human physiological and pathological processes. Due to their abundant cargo including proteins, lipids, and nucleic acids, exosomes have played a valuable diagnostic and therapeutic role across multiple diseases, including cancer. In this review, we summarize recent findings concerning the content within and participation of exosomes relating to OSCC and their roles in tumorigenesis, proliferation, migration, invasion, metastasis, and chemoresistance. We conclude this review by looking ahead to their potential utility in providing new methods for treating OSCC to inspire further research in this field.

CircRNAs: A New Chapter in Oral Squamous Cell Carcinoma Biology

With the rapid development of bioinformatics and gene sequencing technologies, understanding of circular RNAs (circRNAs) has been extended, and numerous studies have identified the key regulator role of circRNAs in a variety of diseases, especially in cancer. Recently, accumulated studies of oral squamous cell carcinoma (OSCC) have discovered the great potential of circRNAs, which can serve as prognostic or diagnostic biomarkers and affect the development and therapy of OSCC. In this review, we detail the new progress of circRNA research for OSCC in order to provide new strategies for clinical diagnosis and treatment.

RNAseq profiling of circRNA expression in radiation-treated A549 cells and bioinformatics analysis of radiation-related circRNA-miRNA networks

With the development of new biochemical and computational methods, circular RNAs (circRNAs) have been identified as microRNA sponges. circRNAs are associated with many diseases, particularly cancer. The present study aimed to investigate the expression profile of circRNAs in irradiated A549 lung cancer cells using high-throughput sequencing. Bioinformatics analyses were used to examine the potential functions of circRNAs. RNA sequencing data demonstrated that 1,875 circRNA targets were differentially expressed in A549 cells in response to irradiation. A total of 30 circRNAs were upregulated and 37 circRNAs were downregulated significantly in irradiation-treated A549 cells (fold change ≥2.0; P<0.05). The top 5 upregulated and downregulated circRNAs were successfully validated by reverse transcription-quantitative PCR. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that differentially expressed circRNAs might be pivotal in biological irradiation responses to irradiation. circRNA-microRNA co-expression networks highlighted the biological significance of circRNA_0002174 and circRNA_0036627, which require further study. In conclusion, the present study is, to the best of the authors' knowledge, the first to describe the differentially expressed profile of circRNAs in response to irradiation in A549 cells. These results provide a new perspective to elucidate insight into the molecular mechanisms by which A549 cells respond to radiation, and a basis for a more in-depth analysis of the potential application of circRNAs in the treatment of lung cancer therapy.

Circular RNA_0001742 has potential to predict advanced tumor stage and poor survival profiles in tongue squamous cell carcinoma management

Background

Circular RNA_0001742 (circ_0001742) has been reported to be upregulated in tongue squamous cell carcinoma (TSCC) tissues/cells and regulate TSCC cell proliferation, migration, and invasion. This study aimed to further investigate the clinical significance of circ_0001742 in TSCC management.

Methods

Totally, 146 TSCC patients underwent surgical treatment were reviewed. Their fresh‐frozen tumor tissue and adjacent tissue were acquired for detecting circ_0001742 expression via reverse transcription‐quantitative polymerase chain reaction. According to circ_0001742 expression in tumor tissue, all patients were classified as tumor circ_0001742 low (0%‐50% percentile) and high (50%‐100% percentile) patients, the latter were further divided into the tumor circ_0001742 high+ (50%‐75% percentile), high++ (75%‐90% percentile), and high+++ (90%‐100% percentile) patients, respectively.

Results

Circ_0001742 expression was increased in TSCC tumor tissue compared with adjacent tissue, and it presented good value in discriminating tumor tissue from adjacent tissue (area under the curve (AUC): 0.870, 95% CI: 0.831‐0.910). Tumor high circ_0001742 expression was associated with higher T stage, N stage, and TNM stage, but not age, gender, or pathological grade. Furthermore, OS was reduced in tumor circ_0001742 high patients compared with tumor circ_0001742 low patients; moreover, OS was the shortest in tumor circ_0001742 high+++ patients, followed by tumor circ_0001742 high++ patients and tumor circ_0001742 high+ patients, and the longest in tumor circ_0001742 low patients. In addition, multivariate Cox's regression analysis revealed that higher tumor circ_0001742 expression was an independent predictive factor for decreased OS.

Conclusion

Circ_0001742 serves as a potential biomarker for advanced tumor stage and poor survival in TSCC patients.

Circular RNAs: from biogenesis and function to diseases

OBJECTIVE

Evidence suggests that various diseases may contribute to the circular RNAs (circRNAs) expression disorder. This review was aimed at looking for appropriate biomarkers for the treatment of diseases.

DATA SOURCES

The comprehensive search used online literature databases including PubMed of National Center for Biotechnology Information and Web of Science.

STUDY SELECTION

The study selection was based on the following keywords: circRNAs, biogenesis, biologic function, and disease. The time limit for literature retrieval was from the year 1976 to 2019, with language restriction in English. Relevant articles were carefully reviewed, with no exclusions applied to study design and publication type.

RESULTS

CircRNAs are one of the critical non-coding RNAs (ncRNAs), which are covalently closed continuous loops that do not possess 5' and 3' ends. This makes them resistant to exoribonuclease activity and potentially more stable than their cognate linear transcripts, thus making them ideal candidates for biomarker development. Due to the stable and extensive tissue-specific expression of circRNAs, they can function as microRNA sponges and bind to RNA-binding proteins, regulate transcription and splicing, and translate into proteins to participate in the regulation of physiologic and pathologic processes. Moreover, the expression disorders of circRNAs in diseases, such as neurodegenerative disease, cardiovascular disease, and cancer, make them have potential applications for the diagnosis and treatment of diseases.

CONCLUSIONS

Changes in circRNA expression profiles related to various diseases, and circRNAs often exhibit low expression in cancer tissues. In addition, circRNAs can be detected in patient's body fluids to indicate that circRNAs are effective biomarkers for disease diagnosis. These characteristics make circRNAs have potential applications as novel therapeutic targets for diseases.

High-throughput sequencing of circRNAs reveals novel insights into mechanisms of nigericin in pancreatic cancer

BACKGROUND

Our previous study had proved that nigericin could reduce colorectal cancer cell proliferation in dose- and time-dependent manners by targeting Wnt/β-catenin signaling. To better elucidate its potential anti-cancer mechanism, two pancreatic cancer (PC) cell lines were exposed to increasing concentrations of nigericin for different time periods, and the high-throughput sequencing was performed to explore the circRNA expression profiles after nigericin exposure on pancreatic cancer (PC) cells.

RESULTS

In this study, a total of 183 common differentially expressed circRNAs were identified, and the reliability and validity of the sequencing data were verified by the PCR analysis. According to the parental genes of circRNAs, the GO analysis was performed to predict the most enriched terms in the biological process, cellular components and molecular functions. The KEGG analysis and pathway-pathway network exhibited the potential signal pathways and their regulatory relationships. Meanwhile, a potential competing endogenous RNA (ceRNA) mechanism through a circRNA-miRNA-mRNA network was applied to annotate potential functions of these common differentially expressed circRNAs, and these predicted miRNAs or mRNAs might be involved in nigericin damage.

CONCLUSIONS

By the bioinformatics method, our data will facilitate the understanding of nigericin in PC cells, and provide new insight into the molecular mechanism of nigericin toward cancer cells. This is the first report that discusses the potential functions of nigericin in cancers through the bioinformatics method. Our data will facilitate the understanding of nigericin-mediated anti-cancer mechanisms in PC.