Value of circular RNA 0007385 in disease monitoring and prognosis estimation in non-small-cell lung cancer patients

Circular RNAs in lung cancer: implications for preventing therapeutic resistance

LC is one of the most common malignant tumours that often presents with no distinct symptoms in the early stages, leading to late diagnoses when patients are at an advanced stage and no longer suitable for surgical treatment. Although adjuvant treatments are available, patients frequently develop tolerance to these treatments over time, resulting in poor prognoses for patients with advanced LC. Recently, circular RNAs (circRNAs), a type of non-coding RNA, have gained significant attention in LC research. Owing to their unique circular structure, circRNAs are highly stable within cells. This review systematically summarises the expression, characteristics, biological functions, and molecular regulatory mechanisms of circRNAs involved in therapy resistance as well as the potential applications in early diagnosis and gene targeting therapy in LC.

In silico analysis revealed the potential circRNA-miRNA-mRNA regulative network of non-small cell lung cancer (NSCLC)

BACKGROUND

The primary source of death in the world is non-small cell lung cancer (NSCLC). However, NSCLCs pathophysiology is still not completely understood. The current work sought to study the differential expression of mRNAs involved in NSCLC and their interactions with miRNAs and circRNAs.

METHODS

We utilized three microarray datasets (GSE21933, GSE27262, and GSE33532) from the GEO NCBI database to identify the differentially expressed genes (DEGs) in NSCLC. We employed DAVID Functional annotation tool to investigate the underlying GO biological process, molecular functions, and KEGG pathways involved in NSCLC. We performed the Protein-protein interaction (PPI) network, MCODE, and CytoHubba analysis from Cytoscape software to identify the significant DEGs in NSCLC. We utilized miRnet to anticipate and build interaction between miRNAs and mRNAs in NSCLC and ENCORI to predict the miRNA-circRNA relationships and build the ceRNA regulatory network. Finally, we executed the gene expression and Kaplan-Meier survival analysis to validate the significant DEGs in the ceRNA network utilizing TCGA NSCLC and GEPIA data.

RESULTS

We revealed a total of 156 overlapped DEGs (47 upregulated and 109 downregulated genes) in NSCLC. The PPI network, MCODE, and CytoHubba analysis revealed 12 hub genes (cdkn3, rrm2, ccnb1, aurka, nuf2, tyms, kif11, hmmr, ccnb2, nek2, anln, and birc5) that are associated with NSCLC. We identified that these 12 genes encode 12 mRNAs that are strongly linked with 8 miRNAs, and further, we revealed that 1 circRNA was associated with this 5 miRNA. We constructed the ceRNAs network that contained 1circRNA-5miRNAs-7mRNAs. The expression of these seven significant genes in LUAD & LUSC (NSCLC) was considerably higher in the TCGA database than in normal tissues. Kaplan-Meier survival plot reveals that increased expression of these hub genes was related to a poor survival rate in LUAD.

CONCLUSION

Overall, we developed a circRNA-miRNA-mRNA regulation network to study the probable mechanism of NSCLC.

Anesthetic propofol suppresses growth and metastasis of lung adenocarcinoma in vitro through downregulating circ-MEMO1-miR-485-3p-NEK4 ceRNA axis

BACKGROUND

Recently, circular RNAs (circRNAs) have been emerging as new regulators in the propofol-induced tumor-suppressive role. Here, we intended to investigate the involvement of circRNA-Mediator of cell motility 1 (circ-MEMO1; hsa_circ_0007385) in propofol role in cancer hallmarks of lung adenocarcinoma (LUAD).

METHODS

Real-time quantitative PCR and western blotting examined transcriptional and translational levels of circ-MEMO1, microRNA (miR)-485-3p, and NIMA-related kinase-4 (NEK4), and markers of growth and metastasis including E-cadherin, CyclinD1, and Vimentin. Cancer hallmarks were measured by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, 5-ethynyl-2-deoxyuridine assay, and transwell assay. The interaction among circ-MEMO1, miR-485-3p, NEK4 was determined by dual-luciferase reporter assay and Pearson's correlation analysis.

RESULTS

Circ-MEMO1 and NEK4 were high-expressed, and miR-485-3p was low-expressed in LUAD patients and cells; moreover, circ-MEMO1 and NEK4 expression in LUAD cells could be suppressed, whereas miR-485-3p could be elevated with propofol anesthesia. Functionally, propofol restrained cell viability, cell cycle entrance, cell proliferation, migration, and invasion of LUAD cells, accompanied by promoted E-cadherin and depressed CyclinD1 and Vimentin. Coincidently, high circ-MEMO1 was associated with low overall survival of LUAD patients, and overexpressing circ-MEMO1 could overall attenuate propofol effects in LUAD cells. Of note, upregulating miR-485-3p and/or interfering NEK4 could partially countermand the adverse impacts of circ-MEMO1 on propofol's role in LUAD cells. Importantly, circ-MEMO1 acted as a sponge for miR-485-3p to modulate the expression of miR-485-3p-targeted oncogene NEK4.

CONCLUSION

Promoting the circ-MEMO1-miR-485-3p-NEK4 axis might halt the tumor-inhibiting role of propofol in LUAD cells in vitro, suggesting a potential epigenetic pathway of propofol.

Role of circular RNAs in the diagnosis, regulation of drug resistance and prognosis of lung cancer (Review)

Lung cancer is one of the most common malignant tumors in China and is the highest cause of mortality among male and female patients, both in urban and rural areas. A subset of patients with lung cancer only display chest tightness without any other obvious symptoms. This is because most symptoms do not manifest during the early stages of disease development. Consequently, most patients with lung cancer are diagnosed when the disease is in the advanced stages, when they are already unfit for surgical treatment. Furthermore, the prognosis of patients with lung cancer is poor. The 5-year survival rate of patients with stage IA lung cancer is 85%, compared with 6% in those with stage IV. This requires the development of strategies for early diagnosis, treatment and prognosis to improve the management of lung cancer. Circular RNAs (circRNAs) belong to a class of closed circular non-coding RNAs formed by reverse splicing of a precursor mRNA. These RNAs are highly stable, ubiquitously expressed, conserved, and show high specificity. CircRNAs regulate biological processes, such as the proliferation, differentiation and invasion of lung cancer cells. Therefore, they can be used as biomarkers for the early diagnosis and prognosis prediction of lung cancer, as well as novel targets for therapy design. In the present review, the biological characteristics and functions of circRNAs, as well as their application in the diagnosis, control of drug resistance and effect on the prognosis of patients with lung cancer, will be discussed.

Biogenesis, functions, and clinical implications of circular RNAs in non-small cell lung cancer

Lung cancer (LC) is the leading cause of cancer-related deaths worldwide, with high morbidity and mortality. Non-small cell lung cancer (NSCLC) is a major pathological type of LC and accounts for more than 80% of all cases. Circular RNAs (circRNAs) are a large class of non-coding RNAs (ncRNAs) with covalently closed-loop structures, a high abundance, and tissue-specific expression patterns. They participate in various pathophysiological processes by regulating complex gene networks involved in proliferation, apoptosis, migration, and epithelial-to-mesenchymal transition (EMT), as well as metastasis. A growing number of studies have revealed that the dysregulation of circRNAs contributes to many aspects of cancer progression, such as its occurrence, metastasis, and recurrence, suggesting their great potential as efficient and specific biomarkers in the diagnosis, prognosis, and therapeutic targeting of NSCLC. In this review, we systematically elucidate the characteristics, biogenesis, and functions of circRNAs and focus on their molecular mechanisms in NSCLC progression. Moreover, we highlight their clinical implications in NSCLC treatment.

CircRNA WHSC1 promotes non-small cell lung cancer progression via sponging microRNA-296-3p and up-regulating expression of AKT serine/threonine kinase 3

Background

Lung cancer is the most commonly diagnosed cancer and leading cause of cancer death, with 80%–85% of non‐small cell lung cancer (NSCLC). Circular RNAs (circRNAs) have been shown to be promising early diagnostic and therapeutic molecular biomarkers for NSCLC. However, biological role and regulatory mechanism of circRNA WHSC1 (circWHSC1) in NSCLC are unknown. Therefore, we aim to explore the function and mechanism of circWHSC1 in NSCLC oncogenesis and progression.

Methods

qRT‐PCR was used for circWHSC1 level evaluation; Kaplan‐Meier was used for survival analysis; bioinformatics, dual‐luciferase activity, and RNA pull‐down were used for evaluating competing endogenous RNA (ceRNA) network; cell viability, colony formation, apoptosis, migration, and invasion were used for cell function analysis; function gain and loss with rescue experiments were used for exploring mechanism of circWHSC1 in NSCLC development.

Results

Significantly up‐regulated circWHSC1 and down‐regulated microRNA‐296‐3p (miR‐296‐3p) were identified in NSCLC tissues and cells. Up‐regulated circWHSC1 was associated with poor prognosis in NSCLC patients. MiR‐296‐3p was sponged by circWHSC1, and AKT serine/threonine kinase 3 (AKT3) was target of miR‐296‐3p; meanwhile, miR‐296‐3p over‐expression significantly down‐regulated AKT3 expression, and co‐transfecting anti‐miR‐296‐3p rescued circWHSC1 silence caused AKT3 down‐regulation. CircWHSC1 silence significantly inhibited colony formation, viability, invasion, and migration, while increased NSCLC cell apoptosis, which were partially rescued by anti‐miR‐296‐3p.

Conclusion

CircWHSC1 is an independent indicator of poor prognosis in NSCLC patients, and functions as a ceRNA of miR‐296‐3p to up‐regulate AKT3, consequently promotes NSCLC cell growth and metastasis. Targeting circWHSC1 might be a prospective strategy for diagnosis, therapeutics, and prognosis of NSCLC.

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.

The roles and mechanisms of the circular RNA circ_104640 in early-stage lung adenocarcinoma: a potential diagnostic and therapeutic target

Background

In recent years, there have been increasing reports that dysregulated circular RNAs (circRNAs) play a key role in the carcinogenesis of lung adenocarcinoma (LUAC). However, the role of circRNAs in early-stage LUAC is poorly understood.

Methods

The Gene Expression Omnibus (GEO) database and qRT-PCR were used to verify the abnormal expression of circRNAs, miRNAs and genes in early-stage LUAC tissues. shRNA and miRNA inhibitor are designed and synthesized to knock down circ_104640 and microRNA (miR)-145-5p expression. CCK-8 assay, colony formation assay and flow cytometry were used to study the effect of circ_104640 on cell proliferation and apoptosis. Bioinformatics analysis, dual luciferase reporter assays and argonaute 2 (Ago2) RNA immunoprecipitation (RIP) assays were chosen to find out the potential target of circ_104640.

Results

Based on the GEO database and tissue sample from our institution, we identified that the circRNA circ_104640, the miR-145-5p, and CCL20 (C-C motif chemokine ligand 20) were abnormally expressed in the tissues of early-stage LUAC. In vitro experiments showed that circ_104640 could exist stably in the cytoplasm, and a short pin RNA that targeted circ_104640 (sh-circ) inhibited cell growth and promoted apoptosis of LUAC cells. Dual luciferase reporter assays and Ago2 (RIP) assays confirmed the Ago2-dependent interaction of circ_104640 and miR-145-5p. In terms of mechanisms, we found that circ_104640 increased the expression of CCL20 by sponging miR-145-5p.

Conclusions

Our research demonstrated that circ_104640 could accelerate the proliferation of LUAC cells, while inhibiting LUAC cell apoptosis. circ_104640 may be a potential novel biomarker and therapeutic target for early-stage LUAC.

Value of circular RNA 0007385 in disease monitoring and prognosis estimation in non-small-cell lung cancer patients

Objective

This study aimed to assess the circular RNA_0007385 (hsa_circ_0007385) expression in tumor/adjacent non‐tumor tissues, and the correlation of its tumor expression with clinicopathological features as well as survival in non–small‐cell lung cancer (NSCLC) patients.

Methods

210 NSCLC patients who underwent tumor resection were reviewed in this retrospective study. 210 tumor specimens and 81 paired adjacent specimens were collected, in which the hsa_circ_0007385 expression was detected by reverse transcription‐quantitative polymerase chain reaction assay. Disease‐free survival (DFS) and overall survival (OS) were recorded, and the last follow‐up date was June 30, 2019.

Results

Hsa_circ_0007385 was upregulated in tumor tissue compared with adjacent non‐tumor tissue (P < .001), and ROC curve analysis revealed that hsa_circ_0007385 expression had an excellent value in distinguishing tumor tissue from adjacent non‐tumor tissue with an area under curve of 0.922 (95% CI: 0.890‐0.953). Tumor hsa_circ_0007385 high expression correlated with lymph node metastasis (P = .007) and higher TNM stage (P = .004). In addition, DFS (P = .028) and OS (P = .008) were both less favorable in patients with tumor hsa_circ_0007385 high expression compared to patients with tumor hsa_circ_0007385 low expression. Besides, the DFS (P = .008) and OS (P = .012) were also the worst in patients with tumor hsa_circ_0007385 high+++ expression, followed by patients with tumor hsa_circ_0007385 high++ expression and patients with tumor hsa_circ_0007385 high + expression, and the best in patients with tumor hsa_circ_0007385 low expression. Multivariate regression analysis elucidated that tumor hsa_circ_0007385 high expression independently predicted worse OS (P = .033).

Conclusion

Tumor hsa_circ_0007385 could be a novel biomarker for disease monitoring and prognosis prediction in NSCLC patients.