circFOXM1 promotes proliferation of non-small cell lung carcinoma cells by acting as a ceRNA to upregulate FAM83D

Impact of Tyrosine Kinase Inhibitors on the Expression Pattern of Epigenetic Regulators

Background: Advances in molecular genetic diagnostics and emerging opportunities for targeted treatment have opened new horizons in precision oncology. Tyrosine kinase inhibitors (TKI) are the subgroup of these agents with which the most clinical experience has been gathered so far. However, little data is available on the effect of TKI agents on the expression levels of molecules responsible for epigenetic regulation. Methods: In this study, we investigated the effect of in vitro and in vivo treatment with tyrosine kinase inhibitor agents on the expression of epigenetic regulators in hematological malignancies and solid tumors, based on data included in the functional genomics repository Gene Expression Omnibus. Results: Statistical analysis of datasets and series of gene expression patterns revealed numerous significant changes in the levels of epigenetic writers, erasers, microRNAs and members of chromatin-remodeling complexes following TKI treatment. Previously published data about the role of these epigenetic modifiers in malignant diseases has also been summarized. Conclusions: Our results may contribute to the establishment of novel treatment strategies aiming at the combinatorial administration of TKI and epidrugs in cancer, leading to less toxic therapy with further improved results.

Circular RNAs in Cell Cycle Regulation of Cancers

Cancer has been one of the most problematic health issues globally. Typically, all cancers share a common characteristic or cancer hallmark, such as sustaining cell proliferation, evading growth suppressors, and enabling replicative immortality. Indeed, cell cycle regulation in cancer is often found to be dysregulated, leading to an increase in aggressiveness. These dysregulations are partly due to the aberrant cellular signaling pathway. In recent years, circular RNAs (circRNAs) have been widely studied and classified as one of the regulators in various cancers. Numerous studies have reported that circRNAs antagonize or promote cancer progression through the modulation of cell cycle regulators or their associated signaling pathways, directly or indirectly. Mostly, circRNAs are known to act as microRNA (miRNA) sponges. However, they also hold additional mechanisms for regulating cellular activity, including protein binding, RNA-binding protein (RBP) recruitment, and protein translation. This review will discuss the current knowledge of how circRNAs regulate cell cycle-related proteins through the abovementioned mechanisms in different cancers.

The role of hydrogen sulfide regulation of pyroptosis in different pathological processes

Pyroptosis is one kind of programmed cell death in which the cell membrane ruptures and subsequently releases cell contents and pro-inflammatory cytokines including IL-1β and IL-18. Pyroptosis is caused by many types of pathological stimuli, such as hyperglycemia (HG), oxidative stress, and inflammation, and is mediated by gasdermin (GSDM) protein family. Increasing evidence indicates that pyroptosis plays an important role in multiple diseases, such as cancer, kidney diseases, inflammatory diseases, and cardiovascular diseases. Therefore, the regulation of pyroptosis is crucial for the occurrence, development, and treatment of many diseases. Hydrogen sulfide (H2S) is a biologically active gasotransmitter following carbon monoxide (CO) and nitrogen oxide (NO) in mammalian tissues. So far, three enzymes, including 3-mercaptopyruvate sulphurtransferase (3-MST), cystathionine γ- Lyase (CSE), and Cystine β-synthesis enzyme (CBS), have been found to catalyze the production of endogenous H2S in mammals. H2S has been reported to have multiple biological functions including anti-inflammation, anti-oxidative stress, anti-apoptosis and so on. Hence, H2S is involved in various physiological and pathological processes. In recent years, many studies have demonstrated that H2S plays a critical role by regulating pyroptosis in various pathological processes, such as ischemia-reperfusion injury, alcoholic liver disease, and diabetes cardiomyopathy. However, the relevant mechanism has not been completely understood. Therefore, elucidating the mechanism by which H2S regulates pyroptosis in diseases will help understand the pathogenesis of multiple diseases and provide important new avenues for the treatment of many diseases. Here, we reviewed the progress of H2S regulation of pyroptosis in different pathological processes, and analyzed the molecular mechanism in detail to provide a theoretical reference for future related research.

Role of circular RNAs in lung cancer

Lung cancer remains a global public health concern with significant research focus on developing better diagnosis/prognosis biomarkers and therapeutical targets. Circular RNAs (circRNAs) are a type of single-stranded RNA molecules that covalently closed and have ubiquitous expression. These molecules have been implicated in a variety of disease mechanisms, including lung cancer, as they exhibit oncogenic or tumor suppressor characteristics. Recent research has shown an important role that circRNAs play at different stages of lung cancer, particularly in lung adenocarcinoma. In this review, we summarize the latest research on circRNAs and their roles within lung cancer diagnosis, as well as on disease mechanisms. We also discuss the knowledge gaps on these topics and possible future research directions.

Non-Coding RNAs as Key Regulators in Lung Cancer

For several decades, most lung cancer investigations have focused on the search for mutations in candidate genes; however, in the last decade, due to the fact that most of the human genome is occupied by sequences that do not code for proteins, much attention has been paid to non-coding RNAs (ncRNAs) that perform regulatory functions. In this review, we principally focused on recent studies of the function, regulatory mechanisms, and therapeutic potential of ncRNAs including microRNA (miRNA), long ncRNA (lncRNA), and circular RNA (circRNA) in different types of lung cancer.

Going circular: history, present, and future of circRNAs in cancer

To date, thousands of highly abundant and conserved single-stranded RNA molecules shaped into ring structures (circRNAs) have been identified. CircRNAs are multifunctional molecules that have been shown to regulate gene expression transcriptionally and post-transcriptionally and exhibit distinct tissue- and development-specific expression patterns associated with a variety of normal and disease conditions, including cancer pathogenesis. Over the past years, due to their intrinsic stability and resistance to ribonucleases, particular attention has been drawn to their use as reliable diagnostic and prognostic biomarkers in cancer diagnosis, treatment, and prevention. However, there are some critical caveats to their utility in the clinic. Their circular shape limits their annotation and a complete functional elucidation is lacking. This makes their detection and biomedical application still challenging. Herein, we review the current knowledge of circRNA biogenesis and function, and of their involvement in tumorigenesis and potential utility in cancer-targeted therapy.

hsa_circ_0000519 promotes the progression of lung adenocarcinoma through the hsa-miR-1296-5p/DARS axis

Emerging research indicates that circRNAs serve a crucial role in occurrence and development of cancers. This study aimed to uncover the biological role of hsa_circ_0000519 in the progression of LUAD (lung adenocarcinoma). hsa_circ_0000519 was identified by bioinformatic analysis, and its differential expression was validated in LUAD tissues and cell lines. CCK8, colony formation, wound healing, transwell assays, and xenograft tumor models were used to observe the biological functions of hsa_circ_0000519. FISH, RIP, dual luciferase reporter assays, and recovery experiments were implemented to explore the underlying mechanisms of hsa_circ_0000519. hsa_circ_0000519 was significantly upregulated in LUAD tissues and cell lines. The expression of hsa_circ_0000519 was positively correlated with T grade and TNM stage in patients with LUAD. Downregulation of hsa_circ_0000519 remarkably reduced cell proliferation, migration, invasion in vitro, and tumor growth in vivo. Mechanistic investigation demonstrated that hsa_circ_0000519 directly sponged hsa-miR-1296-5p to reduce its repressive impact on DARS as well as activate the PI3K/AKT/mTOR signaling pathway. The malignant phenotypes of LUAD cells induced by upregulation of hsa_circ_0000519 could be rescued by hsa-miR-1296-5p overexpression or knockdown of DARS. In conclusion, hsa_circ_0000519 promotes LUAD progression through the hsa-miR-1296-5p/DARS axis and may be expected as a novel biomarker and therapeutic for LUAD.

Involvement of FAM83 Family Proteins in the Development of Solid Tumors: An Update Review

FAM83 family members are a group of proteins that have been implicated in various solid tumors. In this updated review, we mainly focus on the cellular localization, molecular composition, and biological function of FAM83 family proteins in solid tumors. We discussed the factors that regulate abnormal protein expression and alterations in the functional activities of solid tumor cells (including non-coding microRNAs and protein modifiers) and potential mechanisms of tumorigenesis (including the MAPK, WNT, and TGF-β signaling pathways). Further, we highlighted the application of FAM83 family proteins in the diagnoses and treatment of different cancers, such as breast, lung, liver, and ovarian cancers from two aspects: molecular marker diagnosis and tumor drug resistance. We described the overexpression of FAM83 genes in various human malignant tumor cells and its relationship with tumor proliferation, migration, invasion, transformation, and drug resistance. Moreover, we explored the prospects and challenges of using tumor treatments based on the FAM83 proteins. Overall, we provide a theoretical basis for harnessing FAM83 family proteins as novel targets in cancer treatment. We believe that this review opens up open new directions for solid tumor treatment in clinical practice.

Circ-HSP90A expedites cell growth, stemness, and immune evasion in non-small cell lung cancer by regulating STAT3 signaling and PD-1/PD-L1 checkpoint

BACKGROUND

Circular RNAs (circRNAs) are important participators in tumor progression for their stable structure and high tissue-specific expression. The purpose of this research was to clarify the potential and mechanism of a novel circRNA-circ-HSP90A in non-small cell lung cancer (NSCLC).

METHODS

Biological potentials of circ-HSP90A in NSCLC were measured by functional assays. Molecular interaction was assessed by bioinformatics analysis and mechanical assays.

RESULTS

Results depicted that circ-HSP90A was cyclization from its host gene heat shock protein 90 alpha (HSP90A) and was up-regulated in NSCLC cells. Circ-HSP90A depletion retarded proliferation, migration, invasion, and immune evasion. Mechanistically, circ-HSP90A recruited ubiquitin specific peptidase 30 (USP30) to stabilize HSP90A and then stimulated the signal transducer and activator of transcription 3 (STAT3) signaling. Meanwhile, circ-HSP90A sponged miR-424-5p to programmed cell death ligand 1 (PD-L1).

CONCLUSIONS

Our study firstly showed that circ-HSP90A promoted cell growth, stemness, and immune evasion in NSCLC through regulating STAT3 signaling and programmed cell death 1 (PD-1)/PD-L1 checkpoint, mirroring that targeting circ-HSP90A might become a novel target of immunotherapy in NSCLC.

Pan-cancer and single-cell analysis reveals FAM83D expression as a cancer prognostic biomarker

Background: The family with sequence similarity 83 member D (FAM83D) protein is known to play a significant role in many human diseases. However, its role in cancer remains ambiguous. This study aimed to investigate the function of FAM83D in a pan-cancer analysis, with a special focus on breast cancer. Methods: Samples were collected from The Cancer Genome Atlas (TCGA) and used for bioinformatic analysis. Datasets from the Gene Expression Omnibus (GEO) and Genotype-Tissue Expression (GTEx) databases were also analyzed for verification. The potential value of FAM83D as a prognostic and diagnostic biomarker was visualized through R software. The "survival" and "GSVA" package were used for univariate, multivariate and pathway enrichment analyseis. We further analyzed the CancerSEA databases and TISIDB websites for single-cell and immune-related profiling. Lastly, we validated those data in vitro using quantitative reverse transcriptase-polymerase chain reaction (RT‒qPCR), cell counting kit-8 (CCK-8), transwell, flow cytometry, and tumorigenicity assays in a murine cell line model. Results: The expression of FAM83D in tumor samples was significantly higher than in normal tissues for most cancer types in the datasets. We confirmed this finding using RT‒qPCR in a breast cancer cell line. Analysis of multiple datasets suggests that overall survival (OS) was extremely poor for breast cancer patients with high FAM83D expression. The CCK-8 assay demonstrated that MCF-7 cell proliferation was inhibited after genetic silencing of FAM83D. Transwell assay showed that knockdown of FAM83D significantly inhibited the invasion and migration ability of MCF-7 cells compared to the control. The results of flow cytometry showed that silencing FAM83D could block the G1 phase of MCF-7 cells compared with negative groups. The tumorigenicity assay in nude mice indicated that the tumorigenic ability to silence FAM83D decreased compared. Conclusion: Results suggest that FAM83D expression can serve as a valuable biomarker and core gene across cancer types. Furthermore, FAM83D expression is significantly associated with MCF-7 cell proliferation and thus may be a prospective prognostic biomarker especially for breast cancer.

High level of LncRNA MAPKAPK5-AS1 predicts poor prognosis and contributes to the malignant proliferation and EMT of non-small cell lung cancer via sponging miR-490-3p from HMGB2

BACKGROUND

Patients with non-small cell lung cancer (NSCLC) show a low survival rate, owing to the lack of early diagnostic method and high invasiveness. Long non-coding RNA MAPKAPK5-AS1 that regulates tumor genesis and progression through multiple signals, is upregulated and involved in the growth and apoptosis in lung adenocarcinoma (LUAD).

OBJECTIVE

To investigate whether MAPKAPK5-AS1 affected the malignant progression of NSCLC.

METHODS

The levels of MAPKAPK5-AS1, miR-490-3p and HMGB2 in lung cancer were first analyzed through StarBase website, and confirmed by a quantitative reverse transcriptase-PCR (qRT-PCR) assay. The biological functions of NSCLC cells were examined by CCK-8, 5-ethynyl-2'-deoxyuridine (EdU) and flow cytometry assays. The potential binding sequences lncRNA-miRNA and miRNA-mRNA were predicted by StarBase software and verified via dual luciferase reporter experiment. The effects of MAPKAPK5-AS1 on tumor growth were evaluated in a xenografted mice model.

RESULTS

The expression of MAPKAPK5-AS1 was upregulated in tumor tissues from NSCLC patients. Patients with high expression of MAPKAPK5-AS1 had higher tumor size, advanced TNM stage, higher incidence of lymph node and distant metastasis, and shorter overall survival. Knockdown of MAPKAPK5-AS1 inhibited the proliferation, induced apoptosis and blocked epithelial mesenchymal transformation (EMT) of NSCLC cells. Mechanically, MAPKAPK5-AS1 could upregulate the HMGB2 level in NSCLC cells through competitively binding to miR-490-3p. MiR-490-3p inhibitor reversed the roles of MAPKAPK5-AS1 knockdown on tumor cell proliferation, apoptosis and EMT. Also, HMGB2 knockdown suppressed tumor cell malignant phenotypes. Furthermore, interference of MAPKAPK5-AS1 slowed NSCLC tumor growth in vivo.

CONCLUSION

Knockdown of MAPKAPK5-AS1 inhibited the aggressive tumor phenotypes through miR-490-3p/HMGB2 axis in NSCLC. MAPKAPK5-AS1/miR-490-3p/HMGB2 might be potential biomarkers or therapeutic targets for NSCLC.

The function and clinical implication of circular RNAs in lung cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Despite the recent advent of promising new targeted therapies, lung cancer diagnostic strategies still have difficulty in identifying the disease at an early stage. Therefore, the characterizations of more sensible and specific cancer biomarkers have become an important goal for clinicians. Circular RNAs are covalently close, endogenous RNAs without 5' end caps or 3'poly (A) tails and have been characterized by high stability, abundance, and conservation as well as display cell/tissue/developmental stage-specific expressions. Numerous studies have confirmed that circRNAs act as microRNA (miRNA) sponges, RNA-binding protein, and transcriptional regulators; some circRNAs even act as translation templates that participate in multiple pathophysiological processes. Growing evidence have confirmed that circRNAs are involved in the pathogenesis of lung cancers through the regulation of proliferation and invasion, cell cycle, autophagy, apoptosis, stemness, tumor microenvironment, and chemotherapy resistance. Moreover, circRNAs have emerged as potential biomarkers for lung cancer diagnosis and prognosis and targets for developing new treatments. In this review, we will summarize recent progresses in identifying the biogenesis, biological functions, potential mechanisms, and clinical applications of these molecules for lung cancer diagnosis, prognosis, and targeted therapy.

Comprehensive analysis of the expression, prognostic significance, and function of FAM83 family members in breast cancer

BACKGROUND

The FAM83 family plays a key role in tumorigenesis and cancer progression. However, the role of the FAM83 family in the development of breast tumors is unclear to date. This report explores the expression, prognostic significance, and function of the FAM83 family members in breast cancer using public databases.

METHODS

UALCAN database was used to explore the expression of FAM83 family members in breast cancer. Furthermore, we validated the expression of FAM83 family members in twenty pairs of breast cancer and normal tissues by RT-PCR. Kaplan-Meier plotter database was used to explore the prognostic significance of FAM83 family members in breast cancer. GeneMANIA and DAVID databases were used for functional and pathway enrichment analysis of genes co-expressed with FAM83A, FAM83D, FAM83F, and FAM83G. MEXPRESS and UALCAN databases were used to analyze the level of DNA promoter methylation of FAM83A, FAM83D, FAM83F, and FAM83G in breast cancer. TIMER database was utilized to explore the relationships between immune cell infiltration and FAM83A, FAM83D, FAM83F, and FAM83G expression.

RESULTS

Among FAM83 family members, FAM83A, FAM83D, FAM83F, and FAM83G were higher expressed in breast cancer than in normal tissues. We also validated the significant high expression of FAM83A, FAM83D, FAM83F, and FAM83G mRNA in breast cancer than in normal samples. Their increased expression has an adverse prognostic effect on breast cancer patients. These genes co-expressed with FAM83A, FAM83D, FAM83F, and FAM83G might take part in cell proliferation, G2/M transition of the mitotic cell cycle, regulation of apoptosis process and other cancer-related biological processes. In addition, they were mainly enriched in the Hippo signaling pathway, Hedgehog signaling pathway, PI3K/AKT signaling pathway, and other cancer-related pathways. We also found that promoter DNA methylation might regulate the expression of FAM83A, FAM83D, FAM83F, and FAM83G mRNA in most CpG islands. At last, we found the expression of FAM83A, FAM83D, FAM83F, and FAM83G mRNA was significantly related to immune cell infiltration.

CONCLUSIONS

FAM83A, FAM83D, FAM83F, and FAM83G were highly expressed in breast cancer tissues and had an adverse effect on the survival outcomes of breast cancer patients. Also, they were involved in breast cancer-related signal pathways. Therefore, they might serve as potential therapeutic targets for breast cancer clinical treatment.

CircFOXM1 acts as a ceRNA to upregulate SMAD2 and promote the progression of nasopharyngeal carcinoma

Background

In recent years, the development of high‐throughput sequencing technology has promoted the rapid development of circRNA‐related research. Studies have found that circRNA plays a key role in a variety of tumors, but few people study the role of circRNA in nasopharyngeal carcinoma. Under comprehensive treatments, the 5‐year survival rate can reach about 70%, but some patients still have distant metastases or recurrences after treatment. Therefore, it is very important to study the molecular mechanisms of the proliferation and invasion of nasopharyngeal carcinoma.

Methods

QRT‐PCR was applied to detect the relative expression level of circFOXM1 in NPC and nasopharyngeal epithelial cell lines. We knocked down circFOXM1 and studied the influence of circFOXM1 on NPC cells. Nuclear and cytoplasmic RNA isolation experiments, fluorescence in situ hybridization (FISH), bioinformatics analysis, the dual‐luciferase reporter experiment, Western Blot, and other experiments were conducted to verify the relationships among circFOXM1, miR‐136‐5p, and SMAD2. We collected clinical NPC samples to prove the effect of circFOXM1 on the prognosis and treatment of NPC.

Results

In this study, we found that circFOXM1 is highly expressed in nasopharyngeal carcinoma tissue cells compared with adjacent normal tissues and is related to the staging of nasopharyngeal carcinoma. High expression of circFOXM1 indicates a poor prognosis for nasopharyngeal carcinoma. Knockdown of CircFOXM1 inhibited the proliferation and invasion of nasopharyngeal carcinoma cells.

Conclusion

CircFOXM1 promotes the malignant proliferation of nasopharyngeal carcinoma cells by regulating the miR‐136‐5p‐SMAD2 axis.

Circular RNA and Its Roles in the Occurrence, Development, Diagnosis of Cancer

Circular RNAs (circRNAs) are non-coding single-stranded covalently closed circular RNA, mainly produced by reverse splicing of exons of precursor mRNAs (pre-mRNAs). The characteristics of high abundance, strong specificity, and good stability of circRNAs have been discovered. A large number of studies have reported its various functions and mechanisms in biological events, such as the occurrence and development of cancer. In this review, we focus on the classification, characterization, biogenesis, functions of circRNAs, and the latest advances in cancer research. The development of circRNAs as biomarkers in cancer diagnosis and treatment also provides new ideas for studying circRNAs research.

LncRNA HOTAIR promotes proliferation, invasion and migration in NSCLC cells via the CCL22 signaling pathway

Long noncoding RNA (LncRNA) is a new type of regulatory RNA. LncRNA HOX antisense intergenic RNA (HOTAIR), as an oncogene in non-small cell lung cancer (NSCLC), is one of the key determinants of tumor progression. However, its possible molecular mechanism and the immunomodulatory pathway involved in NSCLC are still unclear. This study aims to explore whether HOTAIR promotes proliferation, migration and invasion of the NSCLC cells by inhibiting the expression of C-C Motif Chemokine Ligand 22 (CCL22). We collected 30 clinical samples of cancer and adjacent normal tissues from the patients with NSCLC, using real-time quantitative polymerase chain reaction (RT-qPCR) to detect the LncRNA HOTAIR and CCL22 mRNA expression in tissues. Immunohistochemistry was used to detect the protein expression of CCL22 in cancer and adjacent normal tissues. Cell experiments were conducted to verify that LncRNA HOTAIR regulates the expression of CCL22 and participates in the progress of NSCLC. The antisense oligonucleotide (ASO) probe interfering with LncRNA HOTAIR and the interference fragment of CCL22 (si-CCL22) were constructed. A549 cells were co-transfected with ASO-HOTAIR and si-CCL22. We used RT-qPCR to detect the expression of LncRNA HOTAIR and CCL22 mRNA in the cells, enzyme-linked immunosorbent assay (ELISA) used to detect the CCL22 protein level in the cell supernatant. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was applied to detect cell proliferation, the Flow cytometry to detect cell apoptosis. Finally, the Transwell test was utilized to detect cell migration and invasion. In conclusion, this study suggests that HOTAIR may promote proliferation, migration and invasion of the NSCLC cells by inhibiting CCL22 expression, which may play a key role in NSCLC cell immunity.

Knockdown of circ-RAD23B inhibits non-small cell lung cancer progression via the miR-142-3p/MAP4K3 axis

Background

The development of non‐small cell lung cancer (NSCLC) is associated with the deregulation of circRNAs. The objective of this study was to investigate the effects of circ‐RAD23B in NSCLC.

Methods

Circ‐RAD23B expression, miR‐142‐3p and MAP4K3 was detected by qPCR. Cell proliferation was investigated by CCK‐8 assay and colony formation assay. Cell migration and invasion were assessed by transwell assay. Angiogenesis ability was assessed by tube formation assay. Cell cycle distribution and cell apoptosis were monitored by flow cytometry. The predicted binding relationship between miR‐142‐3p and circ‐RAD23B or MAP4K3 was verified by dual‐luciferase reporter assay. The protein level of MAP4K3 was detected by western blot. Animal models were established to determine the role of circ‐RAD23B in vivo.

Results

Circ‐RAD23B was shown to be upregulated in NSCLC tissues and cells. Knockdown of circ‐RAD23B inhibited proliferation, migration, invasion, angiogenesis and promoted cell cycle arrest and apoptosis in NSCLC cells, and circ‐RAD23B knockdown also impeded tumor growth in vivo. Circ‐RAD23B acted as miR‐142‐3p sponge to inhibit miR‐142‐3p expression and thus enrich the expression of MAP4K3, a target of miR‐142‐3p. Rescue experiments presented that miR‐142‐3p inhibition reversed the effects of circ‐RAD23B knockdown, and MAP4K3 overexpression abolished the effects of miR‐142‐3p restoration. In addition, we found that circ‐RAD23B knockdown led to decreased phosphorylation expression of ERK1/2, JNK and p38, three key groups of the MAPK signaling pathway.

Conclusions

Circ‐RAD23B knockdown inhibited NSCLC development by regulating the miR‐142‐3p/MAP4K3 axis, which might be associated with the inactivation of the MAPK signaling pathway.

Comprehensive Assessment of Serum hsa_circ_0070354 as a Novel Diagnostic and Predictive Biomarker in Non-small Cell Lung Cancer

Background: More and more studies have shown that circular RNAs (circRNAs) play an essential role in the occurrence and development of tumors. Hence, they can be used as biomarkers to assist in diagnosing tumors. This study focuses on exploring the role of circular RNA (hsa_circ_0070354) in the diagnosis and prognosis of non-small cell lung cancer (NSCLC). Materials and Methods: First of all, high-throughput sequencing was used to find the difference in the expression of circular RNA between NSCLC and adjacent tissues. The circRNAs with higher differences in expression were selected to verify their expressions in tissues, cells, and serum using qRT-PCR. Secondly, the hsa_circ_0070354 with a significant difference was chosen as the research goal, and the molecular properties were verified by agarose gel electrophoresis and Sanger sequencing, etc. Then, actinomycin D and repeated freeze-thaw were used to explore the stability and repeatability of hsa_circ_0070354. Finally, the expression of hsa_circ_0070354 in serum of 133 patients with NSCLC and 97 normal donors was detected, and its sensitivity, specificity, and prognosis as tumor markers were statistically analyzed. Results: Hsa_circ_0070354 was highly expressed in tissues, cells, and serum of NSCLC, and it has the characteristics of sensitivity, stability, and repeatability. The ROC curve indicates that hsa_circ_0070354 is superior to conventional tumor markers in detecting NSCLC, and the combined diagnosis is of more significance in the diagnosis. The high expression of hsa_circ_0070354 is closely related to the late-stage, poor differentiation of the tumor and the short survival time of the patients, which is an independent indicator of poor prognosis. Conclusion: Hsa_circ_0070354 is not only a novel sensitive index for the diagnosis of NSCLC but also a crucial marker for bad biological behavior.

Circ_0025039 acts an oncogenic role in the progression of non-small cell lung cancer through miR-636-dependent regulation of CORO1C

Non-small cell lung cancer remains the leading cause of cancer-related death worldwide. Circular RNA plays vital roles in NSCLC progression. This study is designed to reveal the role of circ_0025039 in NSCLC cell malignancy. The RNA expression of circ_0025039, microRNA-636 (miR-636), and coronin 1C was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by Western blot analysis or immunohistochemistry assay. Cell proliferation, migration, invasion, tube formation ability, sphere formation capacity, and apoptosis were investigated by cell counting kit-8, 5-Ethynyl-29-deoxyuridine, transwell assay, tube formation assay, sphere formation assay, and flow cytometry analysis, respectively. Mouse model assay was conducted to reveal the effect of circ_0025039 silencing on tumor formation in vivo. The interaction between miR-636 and circ_0025039 or CORO1C was identified through dual-luciferase reporter and RNA pull-down assays. The expression of circ_0025039 and CORO1C was significantly increased, while miR-636 was decreased in NSCLC tissues and cells compared with controls. Circ_0025039 depletion repressed NSCLC cell proliferation, migration, invasion, tube-forming capacity, and sphere formation ability, but induced cell apoptosis. The neoplasm formation was repressed after circ_0025039 silencing. Additionally, circ_0025039 acted as a sponge for miR-636, which was found to target CORO1C. Importantly, the contribution of circ_0025039 to NSCLC progression was mediated by miR-636/CORO1C axis. Circ_0025039 silencing repressed NSCLC malignant progression by reducing CORO1C expression through miR-636, showing the possibility of circ_0025039 as a therapeutic target for NSCLC.

The involvement of the circFOXM1-miR-432-Gα12 axis in glioma cell proliferation and aggressiveness

Accumulating evidence indicates that circFOXM1 (Hsa_circ_0025033) is highly expressed in several cancers; however, the function of circFOXM1 in glioma and the molecular mechanism have not been well explored. In the present study, we found that expression of circFOXM1 was upregulated in both glioma tissues and cell lines. In addition, circFOXM1 knockdown suppressed glioma-cell proliferation, activated apoptosis in vitro, and repressed tumour growth in vivo. Moreover, we clarified that circFOXM1 binds with miR-432, which was downregulated in glioma cells. Furthermore, we indicated that Gα12, a direct target of miR-432, was highly expressed in glioma cells, and Gα12 silencing might limit the progression of glioma. Rescue assays indicated that Gα12 reversed the inhibitory effect of circFOXM1 silencing on glioma-cell tumorigenesis. In conclusion, circFOXM1 acts as a sponge of miR-432 to promote the proliferation and aggressiveness of glioma cells through the Gα12 signalling pathway.

LncRNA SNHG12 in extracellular vesicles derived from carcinoma-associated fibroblasts promotes cisplatin resistance in non-small cell lung cancer cells

Non-small-cell lung cancer (NSCLC) is defined as the most universally diagnosed class of lung cancer. Cisplatin (DDP) is an effective drug for NSCLC, but tumors are prone to drug resistance. The current study set out to evaluate the regulatory effect of long non-coding RNA (lncRNA) small nucleolar RNA host gene 12 (SNHG12) in extracellular vesicles (EVs) derived from carcinoma-associated fibroblasts (CAFs) on DDP resistance in NSCLC cells. Firstly, NSCLC cells were treated with EVs, followed by detection of cell activity, IC50 values, cell proliferation and apoptosis, and Cy3-SNHG12. We observed that CAFs-EVs promoted IC50 values and cell proliferation and inhibited apoptosis. In addition, we learned that lncRNA SNHG12 carried by CAFs-EVs into NSCLC facilitated DDP resistance of NSCLC cells. Furthermore, ELAV like RNA binding protein 1 (HuR/ELAVL1) binding to lncRNA SNHG12 and X-linked inhibitor of apoptosis (XIAP) was verified and RNA stability of XIAP was also verified CAFs-EVs promoted RNA stability and transcription of XIAP, while silencing HuR could partially-reverse this promoting effect. Further joint experimentation showed that silencing XIAP partially inhibited DDP resistance in NSCLC cells. Additionally, the tumor growth and the positive rate of Ki67 and HuR were detected, which showed that CAFs-oe-EVs promoted the tumor and the positive rate of Ki67, as well as the levels of lncRNA SNHG12, HuR, and XIAP in vivo. Collectively, our findings indicated that lncRNA SNHG12 carried by CAFs-EVs into NSCLC cells promoted RNA stability and XIAP transcription by binding to HuR, thus augmenting DDP resistance in NSCLC cells.

CircTUBGCP3 facilitates the tumorigenesis of lung adenocarcinoma by sponging miR-885-3p

Background

Circular RNAs (circRNAs) act pivotal roles in the progression of multiple malignancies. However, the underlying mechanisms by which hsa_circ_0007031 (circTUBGCP3) contributes to lung adenocarcinoma (LAC) remain largely unknown.

Methods

The association of circTUBGCP3 expression with clinicopathological characteristics and prognosis in patients with LAC was determined by RT-qPCR and fluorescence in situ hybridization. The in vitro functional experiments as well as a subcutaneous tumorigenesis model were executed to estimate the role of circTUBGCP3 in LAC cells. The interaction between circTUBGCP3 and miR-885-3p was confirmed by RNA immunoprecipitation, luciferase gene report and RT-qPCR assays. The effects of circTUBGCP3 on miR-885-3p-mediated Wnt10b/β-catenin signaling were evaluated by Western blot.

Results

The upregulation of circTUBGCP3 or downregulation of miR-885-3p was associated with the pathological stage and poor survival in patients with LAC. Restored expression of circTUBGCP3 facilitated the growth and invasion of LAC cells, but knockdown of circTUBGCP3 harbored the opposite effects. In mechanism, circTUBGCP3 could act as a sponge of miR-885-3p, which suppressed the cell proliferation and colony formation and attenuated the tumor-promoting effects of circTUBGCP3. Wnt10b as a target of miR-885-3p could be upregulated be circTUBGCP3 and indicate poor survival in patient with LAC.

Conclusions

Our findings demonstrated that circTUBGCP3 promoted LAC progression by sponging miR-885-3p, and might represent a prognostic factor for LAC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02356-2.

CircRNA-001241 Mediates Sorafenib Resistance of Hepatocellular Carcinoma Cells by Sponging miR-21-5p and Regulating TIMP3 Expression

Hepatocellular carcinoma (HCC) is one of the major malignancies worldwide and its incidence is on the rise, closely related to advanced liver disease¹. Sorafenib chemotherapy is one of the main treatment options for patients with advanced HCC. Despite several reports on HCC multidrug resistance, the underlying regulatory mechanisms are still unclear. In this study, we found circ-001241 was significantly upregulated in HCC tissues and cells. Knockdown of circ-001241 markedly inhibited HCC cell proliferation and decreased sorafenib-resistance. More importantly, circRNA acts as a ceRNA to suppress the expression and activity of miR-21-5p, leading to the increase in TIMP3 expression. In addition, circRNA-001241 facilitated HCC sorafenib-resistance by regulating the miR-21-5p/TIMP3 axis.Taken together, our study elucidated the oncogenic role of circ-001241 in mediating sorafenib resistance in HCC, providing insights and opportunities to overcome sorafenib resistance in patients with advanced hepatocellular carcinoma.

CircRNA circ_0008037 facilitates tumor growth and the Warburg effect via upregulating NUCKS1 by binding to miR-433-3p in non-small cell lung cancer

BACKGROUND

Circular RNAs (circRNAs) participate in the genesis and progression of tumors, including non-small cell lung cancer (NSCLC). At present, the role and regulatory mechanisms of circRNAs in NSCLC have not been fully elucidated. The aim of this study was to explore the role and regulatory mechanism of circRNA hsa_circ_0008037 (circ_0008037) in NSCLC.

METHODS

Expression of circ_0008037 in NSCLC tissues and cells was detected by quantitative real-time polymerase chain reaction (RT-qPCR). Loss-of-function experiments were performed to analyze the influence of circ_0008037 knockdown on proliferation, migration, invasion, and the Warburg effect of NSCLC cells. Western blotting was utilized for protein analysis. The regulatory mechanism of circ_0008037 was surveyed by bioinformatics analysis, RNA pulldown assay, and dual-luciferase reporter assay. Xenograft assay was used to validate the oncogenicity of circ_0008037 in NSCLC in vivo.

RESULTS

Circ_0008037 was upregulated in NSCLC tissues and cells. Circ_0008037 downregulation reduced tumor growth in vivo and repressed proliferation, migration, invasion, and decreased the Warburg effect of NSCLC cells in vitro. Mechanically, circ_0008037 regulated nuclear ubiquitous casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) expression via sponging miR-433-3p. Furthermore, MiR-433-3p inhibitor reversed the inhibiting influence of circ_0008037 silencing on proliferation, migration, invasion, and the Warburg effect of NSCLC cells. Also, NUCKS1 elevation overturned the repressive influence of miR-433-3p mimic on proliferation, migration, invasion, and the Warburg effect of NSCLC cells.

CONCLUSION

Circ_0008037 accelerated tumor growth and elevated the Warburg effect via regulating NUCKS1 expression by adsorbing miR-433-3p, providing an underlying target for NSCLC treatment.

Regulatory roles of phytochemicals on circular RNAs in cancer and other chronic diseases

As novel non-coding RNAs (ncRNAs), circular RNAs (circRNAs) play an essential role in the pathogenesis of many chronic diseases, and the regulation of these functional molecules has become a research hotspot gradually. Within the past decade, phytochemicals were reported to regulate the expression of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in various chronic diseases, and more recently, most studies focus on the regulatory roles of phytochemicals on circRNAs. Abnormal expression of circRNAs has been identified in chronic diseases like cancer, heart failure, depression and atherosclerosis, and numerous studies have revealed the modulation of circRNAs by phytochemicals including berberine, celastrol, cinnamaldehyde, curcumin, et al. The expression of circRNAs, such as circSATB2 and circFOXM1, were modulated by phytochemicals, and these regulations further affected cell proliferation, apoptosis, migration, invasion, autophagy, chemosensitivity, radiosensitivity and other biological processes. Mechanismly, the circRNAs mainly functioned as miRNA sponge, subsequently affecting miRNA-mediated regulation of target genes and related cell signaling pathways. In this review, we summarized the impact of phytochemicals on circRNAs expression and biological function, and discussed the mechanisms underlying phytochemicals regulating circRNAs in cancer and other chronic diseases.

Hydrogen sulfide exposure induces pyroptosis in the trachea of broilers via the regulatory effect of circRNA-17828/miR-6631-5p/DUSP6 crosstalk on ROS production

Hydrogen sulfide (H₂S) is an air pollutant to cause tracheal injury. Pyroptosis is responsible for tissue injury through reactive oxygen species (ROS) production. Competitive endogenous RNAs (ceRNAs) chelate microRNAs and reduce their inhibitory effect on other transcripts, thus affecting ROS levels and pyroptosis. However, it is not clear how H₂S regulates pyroptosis via the ceRNA axis. Therefore, we established a broilers model of H₂S exposure for 42 days to assess pyroptosis and obtain a ceRNA network by immunohistochemistry and RNA sequencing. We detected pyroptosis induced by H₂S and verified circRNA-IGLL1-17828/miR-6631-5p/DUSP6 axis by a double luciferase reporter assay. We also measured ROS levels and the expression of pyroptotic indicators such as (Caspase1) Casp-1, Interleukin 1β (IL-1β) and Interleukin 1β (IL-18). miR-6631-5p knockdown decreased pyroptotic indicators induced by H₂S. Overexpression of miR-6631-5p or DUSP6 knockdown stimulated ROS generation and upregulated pyroptotic indicators. N-acetyl-_L-cysteine (NAC) decreased pyroptotic indicators and ROS levels both induced by miR-6631-5p. Moreover, circRNA-IGLL1-17828, participated in intermolecular competition as a ceRNA of DUSP6. In conclusion, circRNA-IGLL1-17828/miR-6631-5p/DUSP6 crosstalk regulated H₂S-induced pyroptosis in broilers trachea via ROS generation. This is the first study to reveal regulation mechanism of circRNA-related CeRNAs on pyroptosis induced by H₂S, providing important reference for environmental toxicology.

Hsa_circ_0060937 accelerates non-small cell lung cancer progression via modulating miR-195-5p/HMGB3 pathway

Circular RNAs (circRNAs) exert a critical effect on tumorigenesis and development. Our research aimed to clarify the function and underlying mechanism of circ_0060937 inNSCLC. The concentrations of circ_0060937, miR-195-5p and high-mobility group box 3 (HMGB3) were monitored via qRT-PCR and western blot assays. Additionally, cell proliferation, apoptosis, migration and invasion were assessed using CCK-8, colony formation, flow cytometry and transwell assays. Glycolysis was evaluated via detecting glucose uptake and lactate product. The association between miR-195-5p and circ_0060937/HMGB3 were validated using dual-luciferase reporter, RNA pull-down and RIP assays. Furthermore,in vivo experiment was performed to analyze tumorigenesis.Circ_0060937 and HMGB3 levels were elevated, whereas miR-195-5p level was dropped in NSCLC. Circ_0060937 down-regulation restrainedNSCLC cell proliferation, migration, invasion and glycolysis, and triggered apoptosis. Knockdown of circ_0060937 restrained NSCLC development via absorbing miR-195-5p. Circ_0060937 silencing inhibited NSCLC progression by mediating HMGB3. Besides, circ_0060937 depletion suppressed tumor growth in vivo.Circ_0060937 knockdown hindered NSCLC development and glycolysis via regulating miR-195-5p/HMGB3 pathway.

Dynamic expression of FAM83D in peripheral organs at different ages in mice

The family with sequence similarity 83 member (FAM83D) plays important role in the process of cell division as well as tumour progression. However, the role of FAM83D in tissue development was not well explored. Here, we assessed transcriptional levels of FAM83D and other possibly related genes in organs of mice at different ages and methylation level of FAM83D promoter. Our results indicate the trend of FAM83D expression in mouse testis, liver, lung and small intestine, and its relationship to CYCLINB1 and KI67. Finally, we found no effect of promoter methylation status on FAM83D expression during mice development.

High-throughput sequencing identified circular RNA circUBE2K mediating RhoA associated bladder cancer phenotype via regulation of miR-516b-5p/ARHGAP5 axis

Bladder cancer (BC) is known as a common and lethal urinary malignancy worldwide. Circular RNAs (circRNAs), an emerging non-coding RNA, participate in carcinogenesis process of several cancers including BC. In this study, high-throughput sequencing and RT-qPCR were applied to discover and validate abnormal high expression of circUBE2K in BC tissues. Fluorescence in situ hybridization (FISH) was used to detect hsa_circ_0009154 (circUBE2K) expression and subcellular localization in BC tissues. High circUBE2K predicted unfavorable prognoses in BCs, as well as correlated with clinical features. CCK8, transwell, EdU and wound healing assays demonstrated down-regulating circUBE2K decreased BC cell phenotype as proliferation, invasion, and migration, respectively. Further studies showed that circUBE2K promoted BC progression via sponging miR-516b-5p and enhancing ARHGAP5 expression through regulating RhoA activity. Dual-luciferase reporter, FISH and RNA pulldown assays were employed to verify the relationships among circUBE2K/miR-516b-5p/ARHGAP5/RhoA axis. Down-regulating miR-516b-5p or overexpressing ARHGAP5 restored RhoA activity mediated BC cell properties after silencing circUBE2K. Subcutaneous xenograft and metastasis model identified circUBE2K significantly increased BC cell metastasis and proliferation in-vivo. Taken together, we found that circUBE2K is a tumor-promoting circRNA in BC that functions as a ceRNA to regulate ARHGAP5 expression via sponging miR-516b-5p.

Circular RNAs in Lung Cancer: Recent Advances and Future Perspectives

Globally, lung cancer is the most commonly diagnosed cancer and carries with it the greatest mortality rate, with 5-year survival rates varying from 4–17% depending on stage and geographical differences. For decades, researchers have studied disease mechanisms, occurrence rates and disease development, however, the mechanisms underlying disease progression are not yet fully elucidated, thus an increased understanding of disease pathogenesis is key to developing new strategies towards specific disease diagnoses and targeted treatments. Circular RNAs (circRNAs) are a class of non-coding RNA widely expressed in eukaryotic cells, and participate in various biological processes implicated in human disease. Recent studies have indicated that circRNAs both positively and negatively regulate lung cancer cell proliferation, migration, invasion and apoptosis. Additionally, circRNAs could be promising biomarkers and targets for lung cancer therapies. This review systematically highlights recent advances in circRNA regulatory roles in lung cancer, and sheds light on their use as potential biomarkers and treatment targets for this disease.

LncRNA PCAT18 Promotes Non-Small Cell Lung Cancer Progression by Sponging miR-4319

Introduction

NSCLC (non-small cell lung cancer), the most common type of human cancer, is a main cause of cancer-associated mortality. Accumulating evidence has confirmed that long non-coding RNAs serve crucial roles in NSCLC development.

Methods

The PCAT18 expression in NSCLC tissues and cell lines were evaluated by reverse transcription-quantitative PCR. Cell Counting Kit-8 assays, colony formation study, wound healing assays and transwell invasion assays, and tumor xenograft experiments were performed to investigate the biological functions of PCAT18 in NSCLC. Luciferase reporter, RNA-binding protein immunoprecipitation (RIP) and RNA pull-down assays were further used to explore the association between PCAT18 and miR-4319.

Results

PCAT18 expression was up-regulated in NSCLC tissues and cell lines. Furthermore, PCAT18 silencing inhibited NSCLC cell proliferation, migration and invasion, while co-transfection with a miR-4319 inhibitor reversed these biological effects, and miR-4319 inhibited NSCLC growth in vivo. Additionally, PCAT18 silencing promoted NSCLC cell apoptosis and induced G1 stage arrest. Moreover, luciferase reporter assays illustrated that PCAT18 regulated miR-4319 directly, and a RIP assay and RNA pull-down analysis further demonstrated that miR-4319 inhibited PCAT18 in a RNA-induced silencing complex-dependent manner. Finally, PCAT18 silencing impaired the growth of NSCLC in vivo.

Conclusion

In conclusion, these findings demonstrated that PCAT18 promoted NSCLC development by sponging miR-4319. PCAT18 may serve as a crucial biomarker for the diagnosis and targeted therapy of NSCLC.

An epithelial-mesenchymal transition-related 5-gene signature predicting the prognosis of hepatocellular carcinoma patients

Background

Tumor metastasis is one of the leading reasons of the dismal prognosis of hepatocellular carcinoma (HCC). Epithelial-mesenchymal transition (EMT) is closely associated with tumor metastasis including HCC. The purpose of this study is to construct and validate an EMT-related gene signature for predicting the prognosis of HCC patients.

Methods

Gene expression data of HCC patients was downloaded from The Cancer Genome Atlas (TCGA) database. Gene set enrichment analysis (GSEA) was performed to found the EMT-related gene sets which were obviously distinct between normal samples and paired HCC samples. Cox regression analysis was used to develop an EMT-related prognostic signature, and the performance of the signature was evaluated by Kaplan–Meier curves and time-dependent receiver operating characteristic (ROC) curves. A nomogram incorporating the independent predictors was established. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression levels of the hub genes in HCC cell lines, and the role of PDCD6 in the metastasis of HCC was determined by functional experiments.

Results

An EMT-related 5-gene signature (PDCD6, TCOF1, TRIM28, EZH2 and FAM83D) was constructed using univariate and multivariate Cox regression analysis. Based on the signature, the HCC patients were classified into high- and low-risk groups, and patients in high-risk group had a poor prognosis. Time-dependent ROC and Cox regression analyses suggested that the signature could predict HCC prognosis exactly and independently. The predictive capacity of the signature was also validated in two external cohorts. GSEA results showed that many cancer-related signaling pathways such as PI3K/Akt/mTOR pathway and TGF-β/SMAD pathway were enriched in high-risk group. The result of qRT-PCR revealed that PDCD6, TCOF1 and FAM83D were highly expressed in HCC cancer cells. Among them, PDCD6 were found to promote cell migration and invasion.

Conclusion

The EMT-related 5-gene signature can serve as a promising prognostic biomarker for HCC patients and may provide a novel mechanism of HCC metastasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01864-5.

Circular RNAs in Human Cancer

Circular RNAs (circRNAs) are a class of endogenous single-stranded covalently closed RNAs, primarily produced from pre-mRNAs via non-canonical back-splicing. circRNAs are highly conserved, stable, and expressed in tissue- and development-specific pattern. circRNAs play essential roles in physiological process as well as cancer biology. By the advances of deep sequencing and bioinformatics, the number of circRNAs have increased explosively. circRNAs function as miRNA/protein sponge, protein scaffold, protein recruitment, enhancer of protein function, as well as templates for translation involved in the regulation of transcription/splicing, translation, protein degradation, and pri-miRNA processing in human cancers and contributed to the pathogenesis of cancer. Numerous circRNAs may function in diverse manners. In this review, we survey the current understanding of circRNA functions in human cancer including miRNA sponge, circRNA-protein interaction, and circRNA-encoded protein, and summarize available databases for circRNA annotation and functional prediction.

CircRNAs as promising biomarker in diagnostic and prognostic of lung cancer: An updated meta-analysis

BACKGROUND

As a class of endogenous non-coding RNAs with closed-loop structure, circular RNAs (circRNAs) are receiving more and more attention. CircRNAs have been reported to be widely expressed in various human cancers and are implicated in tumorigenesis and progression. The present study aimed to systematically evaluate the clinicopathological, diagnostic and prognostic values of circRNAs in lung cancer.

METHODS

We searched literature from PubMed, Web of science, Cochrane Library, EMBASE and Ovid online databases up to May 29, 2020. Statistical analyses were undertaken based on Stata 11.0, Meta-DiSc 1.4, and RevMan 5.3 software.

RESULTS

Finally, a total of 63 eligible articles were included in our meta-analysis, including 18 studies for diagnosis, 22 studies for prognosis and 57 studies for clinicopathological features. In terms of diagnostic values, circRNAs could discriminate between lung cancer patients and the normal individuals with a relatively high pooled area under the curve (AUC) of 0.83 (95%CI, 0.80-0.86). For the prognostic values, we found that elevated expression of oncogenic circRNAs could predict poor survival outcomes based on multivariate analysis (HR = 2.430, 95%CI = 2.003-2.948, P < 0.001 for OS; HR = 2.228, 95%CI = 1.289-3.853, P = 0.004 for DFS) while tumor-suppressor circRNAs was correlated with better OS in univariate analysis (HR = 0.627, 95%CI = 0.519-0.757, P < 0.001). The pooled results suggested that elevated expression of carcinogenic circRNAs was associated with tumor size (OR = 1.676, 95%CI = 1.209-2.323, P = 0.002), smoking statue (OR = 1.260, 95%CI = 1.062-1.494, P = 0.008), TNM stage (OR = 2.345, 95%CI = 1.617-3.399, P < 0.001), differentiation grade (OR = 1.843, 95%CI = 1.228-2.765, P = 0.003), and lymphatic metastasis (OR = 2.097, 95%CI = 1.482-2.967, P < 0.001). Moreover, the expression of tumor-suppressor circRNAs was related to the improved clinicopathological features (lymphatic metastasis: OR = 0.536, 95%CI = 0.311-0.926, P = 0.025).

CONCLUSIONS

Our meta-analysis demonstrated that circRNAs could be used as feasible and important biomarkers for diagnosis, prognosis and clinicopathological features in lung cancer.