Downregulating circRNA_0044516 Inhibits Cell Proliferation in Gastric Cancer Through miR-149/Wnt1/β-catenin Pathway

LMGATCDA: Graph Neural Network With Labeling Trick for Predicting circRNA-Disease Associations

Previous studies have proven that circular RNAs (circRNAs) are inextricably connected to the etiology and pathophysiology of complicated diseases. Since conventional biological research are frequently small-scale, expensive, and time-consuming, it is essential to establish an efficient and reasonable computation-based method to identify disease-related circRNAs. In this article, we proposed a novel ensemble model for predicting probable circRNA-disease associations based on multi-source similarity information(LMGATCDA). In particular, LMGATCDA first incorporates information on circRNA functional similarity, disease semantic similarity, and the Gaussian interaction profile (GIP) kernel similarity as explicit features, along with node-labeling of the three-hop subgraphs extracted from each linked target node as graph structural features. After that, the fused features are used as input, and further implied features are extracted by graph sampling aggregation (GraphSAGE) and multi-hop attention graph neural network (MAGNA). Finally, the prediction scores are obtained through a fully connected layer. With five-fold cross-validation, LMGATCDA demonstrated excellent competitiveness against gold standard data, reaching 95.37% accuracy and 91.31% recall with an AUC of 94.25% on the circR2Disease benchmark dataset. Collectively, the noteworthy findings from these case studies support our conclusion that the LMGATCDA model can provide reliable circRNA-disease associations for clinical research while helping to mitigate experimental uncertainties in wet-lab investigations.

Prognostic Value of hsa_circ_0007615 in Epithelial Ovarian Cancer and its Regulatory Effect on Tumor Progression

This study aimed to interrogate the functional and clinical significance of hsa_circ_0007615 in epithelial ovarian cancer (EOC). GSE192410 was screened for upregulated circRNAs in ovarian cancer. The expression levels of hsa_circ_0007615 were evaluated in a patient cohort comprising 113 EOC tissues and matched normal tissues. Subsequently, the prognostic value was confirmed by the relevance of hsa_circ_0007615 with clinical parameters, Kaplan-Meier analysis and Cox proportional risk model. Cell functional analyses were performed in EOC cell lines using a cell proliferation kit, transwell and cell death kit. Our data revealed that hsa_circ_0007615 was significantly upregulated in EOC tissues and cell lines, compared with normal ones. Multivariate survival analysis revealed that hsa_circ_0007615 emerged as an independent risk factor for overall survival and recurrence of EOC patients. Knockdown of hsa_circ_0007615 in EOC cells led to the blocking of cell proliferation, migration and invasion, but an increase of cell death presenting as ferroptosis. Tumor suppressive effects of hsa_circ_0007615 knockdown can be abolished by miR-874-3p inhibition. TUBB3 was a targeting gene of miR-874-3p. Hsa_circ_0007615 has the functional and clinical significance of EOC. Mechanistically, hsa_circ_0007615 may contribute to EOC by sponging miR-874-3p and moderating TUBB3.

Circular RNAs: Emerging roles and new insights in human cancers

Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules formed by mRNA exon back-splicing. Although the circRNA functions remain largely unknown, their currently known biological activities include: acting as competing endogenous RNA (ceRNA) to adsorb microRNA (miRNA), binding proteins, regulating transcription or splicing, and ability to be translated into proteins or peptides. A growing number of studies have found that many circRNAs are abnormally expressed in various cancers, and their dysregulation is highly correlated with tumor progression. Therefore, diagnosis and treatment using circRNAs as biomarkers and therapeutic targets, respectively, has gradually become an attractive research topic. In this review, we introduced the canonical biogenesis pathways and degradation mechanisms of circRNAs. In addition, we examined the biological functions of circRNAs in vivo. Finally, we discussed the current clinical applications and challenges faced by circRNA, and proposed future directions for this promising research field.

A comprehensive insight into the correlation between ncRNAs and the Wnt/β-catenin signalling pathway in gastric cancer pathogenesis

During the past decades, gastric cancer (GC) has emerged as one of the most frequent malignancies with a growing rate of prevalence around the world. Despite considerable advances in therapeutic methods, the prognosis and management of patients with gastric cancer (GC) continue to be poor. As one of the candidate molecular targets in the treatment of many types of cancer, the Wnt/β-catenin pathway includes a family of proteins that have important functions in adult tissue homeostasis and embryonic development. The aberrant regulation of Wnt/β-catenin signaling is strongly correlated with the initiation and development of numerous cancers, including GC. Therefore, Wnt/β-catenin signaling has been identified as one of the main targets for extending therapeutic approaches for GC patients. Non-coding RNAs (ncRNAs), including microRNAs and long ncRNAs, are important components of epigenetic mechanisms in gene regulation. They play vital roles in various molecular and cellular processes and regulate many signaling pathways, such as Wnt/β-catenin pathways. Insights into these regulatory molecules involved in GC development may lead to the identification of potential targets for overcoming the limitations of current therapeutic approaches. Consequently, this review aimed to provide a comprehensive overview of ncRNAs interactions involved in Wnt/β-catenin pathway function in GC with diagnostic and therapeutic perspectives. Video Abstract.

Dishevelled segment polarity protein 2 promotes gastric cancer progression through Wnt/β-catenin pathway

Dishevelled family proteins (DVL1-3), key scaffold proteins, act on canonical and non-canonical Wnt/β-catenin signaling pathway. DVL has been implicated in various tumor progression. However, its role and underlying mechanisms in gastric cancer (GC) remain unclear. The aim of this study was to investigate the role of DVL in GC development using cell lines and 209 GC specimens. We analyzed three orthologs of DVL in GC tissues and paired adjacent non-tumor tissues, and only DVL2 is highly expressed in GC tissues. We also analyzed clinicopathological data on DVL2 expression in gastric cancer specimens. In immunohistochemistry, DVL2 expression was up-regulated in GC tissues compared with paired adjacent non-tumor tissues (153/209, 73.2%). DVL2 expression level was significantly correlated with many clinicopathological parameters such as T stage (P < 0.001) and N stage (P < 0.001). Survival analysis showed that the overall survival (OS) of patients with high expression of DVL2 was significantly shorter than those with low expression. Multivariate Cox regression analysis revealed that DVL2 expression was an important and independent prognostic factor for gastric cancer patients (P = 0.011, HR=1.78, 95%CI (1.14-2.79). Depletion of endogenous DVL2 using short hairpin RNA (shRNA) inhibited GC cell proliferation, migration, and invasion. The abnormal activation of Wnt/β-catenin signaling pathway is mainly achieved through the abnormal expression of DVL2. DVL2 is highly expressed in gastric cancer tissues, which may be a new independent risk factor for the prognosis of gastric cancer patients. In gastric cancer, DVL2 overexpression plays a crucial role in the occurrence and development of gastric cancer, so it may become a new, effective and complementary therapeutic target for gastric cancer.

Circular RNA hsa_circ_0008003 promotes the progression of non-small-cell lung cancer by sponging miR-548I and regulating KPNA4 expression

OBJECTIVE

The study aimed to explore the effect of circ_0008003 on the progression of non-small-cell lung cancer (NSCLC) and its underlying regulation mechanism.

METHODS

Expression of hsa_circ_0008003, miRNA (miR)-548I and karyopherin subunit α 4 (KPNA4) was examined by quantitative real-time polymerase chain reaction. Cell viability and proliferation ability were detected by cell counting kit-8 assay and 5-ethynyl-2'-deoxyuridine assay, respectively. Flow cytometry was performed to monitor cell apoptosis. Western blot assay was used to evaluate the protein levels of KPNA4, Bax, and Bcl-2. Cell migration and invasion were assessed by transwell assays. The targeted relationship between miR-548I and hsa_circ_0008003 or KPNA4 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assays. Furthermore, the role of hsa_circ_0008003 in vivo was investigated by xenograft assay.

RESULTS

Circ_0008003 expression was increased in NSCLC tissues and cell lines. Circ_0008003 knockdown reduced cell viability, migration, invasion, angiogenesis, and caused apoptosis in NSCLC cells. Moreover, miR-548I was targeted by circ_0008003, and miR-548I knockdown reversed the influence of circ_0008003 silence on NSCLC progression. KPNA4 was targeted by miR-548I, and miR-548I overexpression suppressed cell viability, migration, invasion, angiogenesis, and promoted cell apoptosis via decreasing KPNA4. In addition, circ_0008003 regulated KPNA4 expression via miR-548I. Circ_0008003 knockdown decreased NSCLC cell growth in the xenograft model.

CONCLUSION

Circular RNA hsa_circ_0008003 promoted progression in NSCLC by sponging miR-548I and regulating KPNA4 expression, hinting that circ_0008003 participates in NSCLC pathogenesis.

Circ_0044516 inhibits cell proliferation and migration and induces apoptosis in gastric cancer cells by targeting miR-516a-5p

BACKGROUND

Circ_0044516 is highly expressed in gastric cancer, and inhibition of circ_0044516 can promote gastric cancer cell proliferation and induce apoptosis. Bioinformatics analysis predicts that miR-516a-5p binds to circ_0044516. The expression of miR-516a-5p is low in non-small cell lung cancer, but its role is unclear in gastric cancer cells. This study mainly explored the effect of circ_0044516 targeting miR-516a-5p on the proliferation, migration, and apoptosis of gastric cancer cells.

AIM

To explore whether circ_0044516 targets and regulates miR-516a-5p and its effects on the proliferation, migration, and apoptosis of gastric cancer cells.

METHODS

Quantitative real time polymerase chain reaction (qRT-PCR) was first used to detect the expression levels of circ_0044516 and miR-516a-5p in gastric epithelial cells GES-1 and gastric cancer cells (SNU-16 and HGC-27). HGC-27 cells were then divided into si-NC group (transfected with si-NC), si-circ_0044516 group (transfected with si-circ_0044516), miR-NC group (transfected with miR-NC), miR-516a-5p group (transfected with miR-516a-5p), si-circ_0044516 + anti-miR-NC group (co-transfected with si-circ_0044516 and anti-miR-NC), and si-circ_0044516 + anti-miR-516a-5p group (co-transfected with si-circ_0044516 and anti-miR-516a-5p). qRT-PCR was used to detect the expression levels of circ_0044516 and miR-516a-5p, MTT assay was used to detect cell proliferation, flow cytometry was performed to detect cell apoptosis, Transwell assay was used to detect cell migration, Western blot analysis was performed to detect the protein expression of p21, Bcl-2 associated X protein (Bax), B cell lymphoma/lewkmia-2 (Bcl-2), and matrix metalloproteinase 2 (MMP2), and dual luciferase reporter assay was ued to detect the targeting relationship between circ_0044516 and miR-516a-5p.

RESULTS

Compared with gastric epithelial cells GES-1, the expression level of circ_0044516 was increased in gastric cancer cells SNU-16 and HGC-27, and the expression level of miR-516a-5p was decreased. Silencing circ_0044516 or overexpression of miR-516a-5p decreased the survival rate of gastric cancer cells and the number of migrating cells, increased the rate of cell apoptosis and the expression of p21 and Bax proteins, and reduced the expression of Bcl-2 and MMP2 proteins. Circ_0044516 targets and negatively regulates the expression of miR-516a-5p, and inhibition of miR-516a-5p partially restored the effect of silencing circ_0044516 on the proliferation, migration, and apoptosis of gastric cancer cells.

CONCLUSION

Circ_0044516 inhibits cell proliferation and migration and induces apoptosis in gastric cancer cells through targeted negative regulation of miR-516a-5p.

The functional roles of the circRNA/Wnt axis in cancer

CircRNAs, covalently closed noncoding RNAs, are widely expressed in a wide range of species ranging from viruses to plants to mammals. CircRNAs were enriched in the Wnt pathway. Aberrant Wnt pathway activation is involved in the development of various types of cancers. Accumulating evidence indicates that the circRNA/Wnt axis modulates the expression of cancer-associated genes and then regulates cancer progression. Wnt pathway-related circRNA expression is obviously associated with many clinical characteristics. CircRNAs could regulate cell biological functions by interacting with the Wnt pathway. Moreover, Wnt pathway-related circRNAs are promising potential biomarkers for cancer diagnosis, prognosis evaluation, and treatment. In our review, we summarized the recent research progress on the role and clinical application of Wnt pathway-related circRNAs in tumorigenesis and progression.

Circular RNA circRNA_0067934 promotes glioma development by modulating the microRNA miR-7/ Wnt/β-catenin axis

Glioma, one of the most prevalent malignant tumors, is well-known for its poor prognosis and low survival rate among patients. As a type of non-coding RNA, circular RNAs (circRNAs) play a significant role in tumor progression. However, the function and role of circRNAs in glioma development remain unclarified. In our experiments, the relative expression level of circRNA_0067934 and miR-7 in glioma tissue was detected by qRT-PCR, and specific gene knockdown was mediated by siRNA and miRNA-inhibitor. Dual-luciferase reporter assay was carried out to determine whether miR-7 successfully targeted circRNA_0067934. Also, CCK-8 and Transwell were performed to evaluate the malignant behaviors of glioma tissues. Western blotting and immunofluorescence were used to evaluate relative protein expression levels. The results of qRT-PCR indicated that circRNA_0067934 was over-expressed in glioma tissues, and down regulation of circRNA_0067934 reduced the tumor progression by inhibiting cell proliferation, invasion, and migration. The relative expression level of miR-7 was significantly reduced in glioma tissues, which showed a negative association with the expression of circRNA_0067934. CircRNA_0067934 could tagete the miR-7 to regulate progression of glioma cell. In addition, the Wnt/β-catenin signaling pathway might involve in down stream regulation of circRNA_0067934 and miR-7. In conclusion, our results revealed that circRNA_0067934 regulates glioma cells progression by targeting miR-7/ Wnt/β-catenin axis.

Circular RNA 0000654 facilitates the growth of gastric cancer cells through absorbing microRNA-149-5p to up-regulate inhibin-beta A

Circular (circ) RNAs are differentially expressed in gastric cancer (GC) and participate in the biological growth of tumor cells. Given that, investigations were performed to unravel the function of circ_0000654 in GC. GC tissue and normal tissue specimens were obtained, in which circ_0000654, microRNA (miR)-149-5p, and inhibin-beta A (INHBA) levels were examined. GC cell line (BGC-823) was transfected to alter circ_0000654 and miR-149-5p expression, thereby observing cell malignancy. Stably-transfected BGC-823 cells were injected into nude mice to observe tumor growth in vivo. The interaction circ_0000654, miR-149-5p, and INHBA was validated. circ_0000654 and INHBA were up-regulated but miR-149-5p was down-regulated in GC. circ_0000654 absorbed miR-149-5p to target INHBA. Silencing circ_0000654inhibited the progress of GC cell biology. Oppositely, restoring circ_0000654 enhanced the growth of GC cells. Inhibiting miR-149-5p rescued down-regulated circ_0000654-induced anti-tumor effect on GC. circ_0000654 silence or miR-149-5p overexpression limited the growth of GC tumors in vivo. Obviously, circ_0000654 facilitates the growth of GC cells through absorbing miR-149-5p to up-regulate INHBA.

Circular RNA circ_0000423 promotes gastric cancer cell proliferation, migration and invasion via the microR-582-3p/Disheveled-Axin domain containing 1 axis

For humans, gastric cancer (GC) is a common malignancy. Multiple circular RNAs (circRNAs) have been confirmed to be important cancer-promoting or tumor-suppressive factors. The present study discusses the roles and mechanisms of circ_0000423 in GC development. In this study, circ_0000423 expression in GC patient tissue samples and cell lines was detected via quantitative real-time polymerase chain reaction. Disheveled-Axin domain containing 1 (DIXDC1) expression in GC cells was examined via Western blot. Besides, cell counting kit-8 was utilized for detecting GC cell viability. GC cell migration and invasion were examined through Transwell assays. Bioinformatics and dual-luciferase reporter gene assays were employed to verify the regulatory relationships between microRNA-582-3p (miR-582-3p) and circ_0000423 or DIXDC1. In the present study, we demonstrated that circ_0000423 was highly expressed in GC. Circ_0000423 knockdown suppressed GC cell viability, migration and invasion. Moreover, miR-582-3p was confirmed as a direct target of circ_0000423, and an upstream regulator of DIXDC1. MiR-582-3p inhibition or DIXDC1 overexpression could reverse the above-mentioned effects of knocking down circ_0000423 on GC cells. In conclusion, circ_0000423 facilitates GC progression by modulating the miR-582-3p/DIXDC1 axis.

Role of circular RNAs in gastrointestinal tumors and drug resistance

The incidence of gastrointestinal cancers has increased significantly over the past decade and gastrointestinal malignancies now rank among the leading causes of mortality globally. Although newer therapeutic strategies such as targeted therapies have greatly improved patient outcomes, their clinical success is limited by drug resistance, treatment failure and recurrence of metastatic disease. Therefore, there is an urgent need for further research identifying accurate and reliable biomarkers for precise treatment strategies. Circular RNAs (circRNAs) exhibit a covalently closed structure, high stability and biological conservation, and their expression is associated with the occurrence and development of gastrointestinal tumors. Moreover, circRNAs may significantly influence drug resistance of gastrointestinal cancers. In this article, we review the role of circRNAs in the occurrence and development of gastrointestinal cancer, their association with drug resistance, and potential application for early diagnosis, treatment and prognosis in gastrointestinal malignancies. Furthermore, we summarize characteristics of circRNA, including mechanism of formation and biological effects via mRNA sponging, chromatin replication, gene regulation, translational modification, signal transduction, and damage repair. Finally, we discuss whether circRNA-related noninvasive testing may be clinically provided in the future. This review provides new insights for the future development of diagnostics and therapeutics based on circRNAs in gastrointestinal tumors.