Circ_0006089 promotes gastric cancer growth, metastasis, glycolysis and angiogenesis by regulating miR‐361‐3p/TGFB1

Reprogramming of glucose metabolism: The hallmark of malignant transformation and target for advanced diagnostics and treatments

Reprogramming of cancer metabolism has become increasingly concerned over the last decade, particularly the reprogramming of glucose metabolism, also known as the "Warburg effect". The reprogramming of glucose metabolism is considered a novel hallmark of human cancers. A growing number of studies have shown that reprogramming of glucose metabolism can regulate many biological processes of cancers, including carcinogenesis, progression, metastasis, and drug resistance. In this review, we summarize the major biological functions, clinical significance, potential targets and signaling pathways of glucose metabolic reprogramming in human cancers. Moreover, the applications of natural products and small molecule inhibitors targeting glucose metabolic reprogramming are analyzed, some clinical agents targeting glucose metabolic reprogramming and trial statuses are summarized, as well as the pros and cons of targeting glucose metabolic reprogramming for cancer therapy are analyzed. Overall, the reprogramming of glucose metabolism plays an important role in the prediction, prevention, diagnosis and treatment of human cancers. Glucose metabolic reprogramming-related targets have great potential to serve as biomarkers for improving individual outcomes and prognosis in cancer patients. The clinical innovations related to targeting the reprogramming of glucose metabolism will be a hotspot for cancer therapy research in the future. We suggest that more high-quality clinical trials with more abundant drug formulations and toxicology experiments would be beneficial for the development and clinical application of drugs targeting reprogramming of glucose metabolism.This review will provide the researchers with the broader perspective and comprehensive understanding about the important significance of glucose metabolic reprogramming in human cancers.

Exploring the impact of circRNAs on cancer glycolysis: Insights into tumor progression and therapeutic strategies

Cancer cells exhibit altered metabolic pathways, prominently featuring enhanced glycolytic activity to sustain their rapid growth and proliferation. Dysregulation of glycolysis is a well-established hallmark of cancer and contributes to tumor progression and resistance to therapy. Increased glycolysis supplies the energy necessary for increased proliferation and creates an acidic milieu, which in turn encourages tumor cells' infiltration, metastasis, and chemoresistance. Circular RNAs (circRNAs) have emerged as pivotal players in diverse biological processes, including cancer development and metabolic reprogramming. The interplay between circRNAs and glycolysis is explored, illuminating how circRNAs regulate key glycolysis-associated genes and enzymes, thereby influencing tumor metabolic profiles. In this overview, we highlight the mechanisms by which circRNAs regulate glycolytic enzymes and modulate glycolysis. In addition, we discuss the clinical implications of dysregulated circRNAs in cancer glycolysis, including their potential use as diagnostic and prognostic biomarkers. All in all, in this overview, we provide the most recent findings on how circRNAs operate at the molecular level to control glycolysis in various types of cancer, including hepatocellular carcinoma (HCC), prostate cancer (PCa), colorectal cancer (CRC), cervical cancer (CC), glioma, non-small cell lung cancer (NSCLC), breast cancer, and gastric cancer (GC). In conclusion, this review provides a comprehensive overview of the significance of circRNAs in cancer glycolysis, shedding light on their intricate roles in tumor development and presenting innovative therapeutic avenues.

CircRNAs: Pivotal modulators of TGF-β signalling in cancer pathogenesis

The intricate molecular landscape of cancer pathogenesis continues to captivate researchers worldwide, with Circular RNAs (circRNAs) emerging as pivotal players in the dynamic regulation of biological functions. The study investigates the elusive link between circRNAs and the Transforming Growth Factor-β (TGF-β) signalling pathway, exploring their collective influence on cancer progression and metastasis. Our comprehensive investigation begins by profiling circRNA expression patterns in diverse cancer types, revealing a repertoire of circRNAs intricately linked to the TGF-β pathway. Through integrated bioinformatics analyses and functional experiments, we elucidate the specific circRNA-mRNA interactions that modulate TGF-β signalling, unveiling the regulatory controls governing this crucial pathway. Furthermore, we provide compelling evidence of the impact of circRNA-mediated TGF-β modulation on key cellular processes, including epithelial-mesenchymal transition (EMT), migration, and cell proliferation. In addition to their mechanistic roles, circRNAs have shown promise as diagnostic and prognostic biomarkers, as well as potential molecular targets for cancer therapy. Their ability to modulate critical pathways, such as the TGF-β signalling axis, underscores their significance in cancer biology and clinical applications. The intricate interplay between circRNAs and TGF-β is dissected, uncovering novel regulatory circuits that contribute to the complexity of cancer biology. This review unravels a previously unexplored dimension of carcinogenesis, emphasizing the crucial role of circRNAs in shaping the TGF-β signalling landscape.

EIF4A3-Bound hsa_circ_0006847 Exerts a Tumor-Suppressive Role in Gastric Cancer

Numerous studies have shown that circular RNAs are associated with the occurrence and development of various cancers, but the biological functions and mechanisms of hsa_circ_0006847 (circASPHD1) in gastric cancer (GC) remain unclear. The expression of hsa_circ_0006847 in GC cell lines, tissue, and plasma from GC patients was assayed by quantitative real-time reverse transcription-polymerase chain reaction. Hsa_circ_0006847 expression in cells was downregulated or upregulated by transfected small interfering RNA (siRNA) or overexpression plasmid. The role of hsa_circ_0006847 in GC was investigated with Cell Counting Kit-8, EdU, Transwell, flow cytometry assays, and in a subcutaneous xenograft tumor model. In addition, the interaction of eukaryotic translation initiation factor 4A3 (EIF4A3) and hsa_circ_0006847 was determined with western blot, biotin-labeled RNA pull-down, and RNA immunoprecipitation assays. Co-immunoprecipitation and mass spectrometry were used to validate the combination of EIF4A3 and synaptopodin-2 (SYNPO2). The expression of hsa_circ_0006847 was decreased in GC tissues and cells and indicated poor survival and prognosis. Overexpression of hsa_circ_0006847 inhibited cell proliferation, migration, and invasion. Flow cytometry showed that upregulation of hsa_circ_0006847 resulted in promotion of apoptosis of GC cells and inhibited their progression through the G0/G1 phase. Downregulation of hsa_circ_0006847 expression had the opposite effects. Overexpression of hsa_circ_0006847 in subcutaneous tumor xenografts inhibited tumor growth. Mechanically, hsa_circ_0006847 promoted the binding of EIF4A3 to SYNPO2 by recruiting EIF4A3, which inhibited the growth of GC. The tumor suppressor activity of hsa_circ_0006847, inhibition of the occurrence and development of GC, was mediated by promotion of EIF4A3 and the binding of EIF4A3 to SYNPO2. The results support the study of hsa_circ_0006847 as a novel therapeutic target for the treatment of GC.

Development of a CD8+ T cell associated signature for predicting the prognosis and immunological characteristics of gastric cancer by integrating single-cell and bulk RNA-sequencing

The universally poor clinical outcome makes gastric cancer (GC) still a significant public health threat, the main goal of our research is to develop a prognostic signature that can forecast the outcomes and immunological characteristics of GC via integrating single-cell and bulk RNA-sequencing. The CD8+ T cell feature genes were screened out by exploring single-cell RNA-sequencing (scRNA-seq) profiles retrieved from the TISCH2 database. Then, Cox and LASSO regressions were exploited for constructing a prognostic model in TCGA cohort based on these CD8+ T cell feature genes. Survival analysis was conducted to investigate the predictive capability of the signature for the clinical outcome of GC patients in TCGA and GEO cohorts. Additionally, we further examined the correlations between the risk signature and tumor immunotherapeutic response from the perspectives of immune infiltration, tumor mutation burden (TMB), immune checkpoint biomarker (ICB) expression, tumor microenvironment (TME), microsatellite instability (MSI), TIDE, and TCIA scores. In total, 703 CD8+ T cell feature genes were identified, eight of which were selected for constructing a prognostic signature. GC patients who possess high-risk score had significantly poorer survival outcomes than those who possess low-risk score in TCGA and GEO cohorts. Immune infiltration analysis proved that the risk score was negatively connected with the infiltration abundance of CD8+ T cells. Then, our findings demonstrated that GC patients in the high-risk subgroup possess a higher proportion of MSI-L/MSS, lower immune checkpoint biomarker expression, lower TMB, higher TIDE scores and lower TCIA scores compared to those in the low-risk subgroup. What's more, immunotherapy cohort analysis confirmed that patients who possess high-risk score are not sensitive to anti-cancer immunotherapy. Our study developed a reliable prognostic signature for GC that was significantly correlated with the immune landscape and immunotherapeutic responsiveness. The risk signature may guide clinicians to adopt more accurate and personalized treatment strategies for GC patients.

Exosomal miR-361-3p promotes the viability of breast cancer cells by targeting ETV7 and BATF2 to upregulate the PAI-1/ERK pathway

BACKGROUND

Malignant progression is the major cause of poor prognosis in breast cancer (BC) patients. Plasma exosomal miRNAs have been reported to be involved in tumor progression, but their roles in BC remain unclear.

METHODS

We performed plasma exosomal miRNA sequencing on 45 individuals, including healthy controls and nonmetastatic and metastatic BC patients. We examined the correlation between miRNA expression in tumor tissues and plasma exosomes in BC patients by qRT‒PCR. The effects of exosomal miR-361-3p on BC cells were determined by CellTiter-Glo, migration and wound healing assays. The target genes of miR-361-3p and downstream pathways were explored by dual-luciferase reporter assay, RNA knockdown, rescue experiments, and western blotting. We utilized murine xenograft model to further assess the impact of plasma exosomal miR-361-3p on the malignant progression of BC.

RESULTS

We found that the expression level of plasma exosomal miR-361-3p gradually increased with malignant progression in BC patients, and the expression of miR-361-3p in plasma exosomes and BC tissues was positively correlated. Consistently, exosomal miR-361-3p enhanced the migration and proliferation of two BC cell lines, MDA-MB-231 and SK-BR-3. Furthermore, our data showed that miR-361-3p inhibited two novel target genes, ETV7 and BATF2, to activate the PAI-1/ERK pathway, leading to increased BC cell viability. Finally, the consistency of the in vivo experimental results supported that elevated plasma exosomal miR-361-3p promote the malignant progression of BC.

CONCLUSIONS

We found for the first time that plasma exosomal miR-361-3p was associated with malignant progression in BC patients. Mechanistically, exosomal miR-361-3p can enhance the migration and proliferation of BC cells by targeting the ETV7 and BATF2/PAI-1/ERK pathways. Our data suggest that plasma exosomal miR-361-3p has the potential to serve as a biomarker for predicting malignant progression in BC patients.

Circular RNAs-mediated angiogenesis in human cancers

Circular RNAs (circRNAs) as small non-coding RNAs with cell, tissue, or organ-specific expression accomplish a broad array of functions in physiological and pathological processes such as cancer development. Angiogenesis, a complicated multistep process driving a formation of new blood vessels, speeds up tumor progression by supplying nutrients as well as energy. Abnormal expression of circRNAs reported to affect tumor development through impressing angiogenesis. Such impacts are introduced as constant with different tumorigenic features known as "hallmarks of cancer". In addition, deregulated circRNAs show possibilities to prognosis and diagnosis both in the prophecy of prognosis in malignancies and also their prejudice from healthy individuals. In the present review article, we have evaluated the angiogenic impacts and anti-angiogenic managements of circRNAs in human cancers.

The Role of the Transforming Growth Factor-β Signaling Pathway in Gastrointestinal Cancers

Transforming growth factor-β (TGF-β) has attracted attention as a tumor suppressor because of its potent growth-suppressive effect on epithelial cells. Dysregulation of the TGF-β signaling pathway is considered to be one of the key factors in carcinogenesis, and genetic alterations affecting TGF-β signaling are extraordinarily common in cancers of the gastrointestinal system, such as hereditary nonpolyposis colon cancer and pancreatic cancer. Accumulating evidence suggests that TGF-β is produced from various types of cells in the tumor microenvironment and mediates extracellular matrix deposition, tumor angiogenesis, the formation of CAFs, and suppression of the anti-tumor immune reaction. It is also being considered as a factor that promotes the malignant transformation of cancer, particularly the invasion and metastasis of cancer cells, including epithelial-mesenchymal transition. Therefore, elucidating the role of TGF-β signaling in carcinogenesis, cancer invasion, and metastasis will provide novel basic insight for diagnosis and prognosis and the development of new molecularly targeted therapies for gastrointestinal cancers. In this review, we outline an overview of the complex mechanisms and functions of TGF-β signaling. Furthermore, we discuss the therapeutic potentials of targeting the TGF-β signaling pathway for gastrointestinal cancer treatment and discuss the remaining challenges and future perspectives on targeting this pathway.

LncRNA FBXO18-AS promotes gastric cancer progression by TGF-β1/Smad signaling

For the digestive system, there exists one common malignant tumor, known as gastric cancer. It is the third most prevalent type of tumor among different tumors worldwide. It has been reported that long noncoding RNAs (lncRNAs), participate in various biological processes of gastric cancer. However, there are still many lncRNAs with unknown functions, and we discovered a novel lncRNA designated as FBXO18-AS. Whether lncRNAFBXO18-AS participates in gastric cancer progression is still unknown. Bioinformatic analysis, immunohistochemistry, Western blotting, and qPCR were carried out to explore FBXO18-AS and TGF-β1 expression. In addition, EdU, MTS, migration and transwell assays were performed to investigate the invasion, proliferation and migration of gastric cancer in vitro. We first discovered that FBXO18-AS expression was upregulated in gastric cancer and linked to poorer outcomes among patients with gastric cancer. Then, we confirmed that FBXO18-AS promoted the proliferation, invasion, migration, and an EMT-like process in gastric cancer in vivo and in vitro. Mechanistically, FBXO18-AS was found to be involved in the progression of gastric cancer by modulating TGF-β1/Smad signaling. Therefore, it might offer a possible biomarker for gastric cancer diagnosis and an effective strategy for clinical treatment.

Role of circRNAs in gastric cancer

Circular RNAs (circRNAs) are a large class of non-coding RNAs with single-strand covalently closed loops, formed by reverse splicing, which widely exist in many cell lines and diverse species. Some circRNAs have highly evolutionarily conserved sequences, or tissue-specific or cell-specific expression patterns, and many circRNAs are extremely stable. In the past decades, accumulating evidence has indicated that circRNAs participate in the mechanisms associated with the development of many kinds of tumors, exert important biological functions by acting as microRNA or protein ‘sponges’, transcriptional regulatory factors, and protein translation templates, and play key roles in the occurrence and development of gastric cancer. This review comprehensively summarizes the biogenesis, characteristics, and biological functions of circRNAs, and the molecular mechanisms underlying the role of circRNAs in the carcinogenesis and progression of gastric cancer.

Serum circular RNA hsa_circ_0000702 as a novel biomarker for diagnosis of gastric cancer

BACKGROUND

There is mounting evidence that Circular RNAs (circRNAs) are essential for the initiation and development of gastric cancer (GC). In this study, we further investigated the clinical importance and applicability of serum hsa_circ_0000702 in the diagnosis and treatment of GC.

METHODS

Sanger sequencing, agarose gel electrophoresis, and RNase R assay were used to confirm the origin, alterations, and stability of hsa_circ_0000702 in GC patients. Real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the expression level of hsa_circ_0000702 in GC cell lines, serum, and tissues. Additionally, receiver operating characteristic (ROC) curves were built to evaluate their prognostic value and how well they would work in conjunction with popular biochemical markers for GC. Finally, real-time dynamic monitoring was used to assess its prognostic usefulness.

RESULTS

Hsa_circ_0000702 exhibited the fundamental traits of circRNA. Hsa_circ_0000702 had good sensitivity, specificity, and stability. It was discovered that hsa_circ_0000702 was down-regulated in GC cell lines, serum, and tissues, and that the level of tumor differentiation and tumor node metastasis (TNM) staging were connected with serum hsa_circ_0000702. The area under the ROC curve of serum hsa_circ_0000702 was calculated to be 0.745 (95% CI: 0.669-0.821), indicating high diagnostic efficacy. The diagnostic value was greatly increased by combining serum CEA and CA19-9. Finally, preoperative and postoperative dynamic monitoring revealed serum hsa_circ_0000702 to be of clinical application.

CONCLUSION

Serum hsa_circ_0000702 was variably expressed in GC patients, indicating that serum hsa_circ_0000702 may be a novel biomarker for GC diagnosis and dynamic monitoring.

Research progress of circRNA in malignant tumour metabolic reprogramming

Cancer is a multi-factor systemic malignant disease, which has seriously threatened human health and created a heavy burden on the world economy. Metabolic reprogramming, one of the important signs of malignant tumours, provides necessary nutrition for tumorigenesis and cancer development; thus, it has recently become a research hot spot, even though the metabolic mechanism is quite intricate. Circular RNA (circRNA) affects cancer cell metabolism through various molecular mechanisms, playing an important role in promoting or suppressing cancer. Because of the structure characteristics, circRNA is quite stable, and can be utilized as biomarkers. In this review, we analysed and summarized the characteristics and biological functions of circRNA and comprehensively reviewed and discussed the important role of circRNA in cancer metabolic reprogramming. This review will provide new ideas for developing new anti-cancer therapeutic targets, mining cancer diagnostic and prognostic markers, and will provide guidance for other researchers to design circRNA-related experiments and develop anti-tumour drugs.

IGF2BP2-induced circRUNX1 facilitates the growth and metastasis of esophageal squamous cell carcinoma through miR-449b-5p/FOXP3 axis

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most common digestive malignancies with relatively high morbidity and mortality. Emerging evidence suggests circular RNAs (circRNAs) play critical roles in tumor cell malignancy. However, the biological function and clinical significance of many circRNAs in ESCC remain elusive.

METHODS

The expression level and clinical implication of circRUNX1 in ESCC tissues were evaluated using qRT-PCR. In vitro and in vivo functional studies were conducted to investigate the underlying biological effects of circRUNX1 on ESCC cell growth and metastasis. Moreover, bioinformatics analysis, RNA sequencing (RNA-seq), RNA immunoprecipitation (RIP) assays, dual-luciferase reporter assays, and rescue experiments were performed to explore the relationships between circRUNX1, miR-449b-5p, Forkhead box protein P3 (FOXP3), and insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2).

RESULTS

CircRUNX1 was found to be significantly up-regulated in ESCC tissues and associated with TNM stage and differentiation grade. Functionally, circRUNX1 promoted ESCC cell proliferation and metastasis in vitro and in vivo. CircRUNX1 enhanced FOXP3 expression by competitively sponging miR-449b-5p. Notably, both miR-449b-5p mimics and FOXP3 knockdown restored the effects of circRUNX1 overexpression on cell proliferation and metastasis. Furthermore, IGF2BP2 binding to circRUNX1 prevented its degradation.

CONCLUSIONS

IGF2BP2 mediated circRUNX1 functions as an oncogenic factor to facilitate ESCC progression through the miR-449b-5p/FOXP3 axis, implying that circRUNX1 has the potential to be a promising diagnostic marker and therapeutic target for ESCC patients.

Critical Roles of Circular RNA in Tumor Metastasis via Acting as a Sponge of miRNA/isomiR

Circular RNAs (circRNAs), a class of new endogenous non-coding RNAs (ncRNAs), are closely related to the carcinogenic process and play a critical role in tumor metastasis. CircRNAs can lay the foundation for tumor metastasis via promoting tumor angiogenesis, make tumor cells gain the ability of migration and invasion by regulating epithelial-mesenchymal transition (EMT), interact with immune cells, cytokines, chemokines, and other non-cellular components in the tumor microenvironment, damage the normal immune function or escape the immunosuppressive network, and further promote cell survival and metastasis. Herein, based on the characteristics and biological functions of circRNA, we elaborated on the effect of circRNA via circRNA-associated competing endogenous RNA (ceRNA) network by acting as miRNA/isomiR sponges on tumor angiogenesis, cancer cell migration and invasion, and interaction with the tumor microenvironment (TME), then explored the potential interactions across different RNAs, and finally discussed the potential clinical value and application as a promising biomarker. These results provide a theoretical basis for the further application of metastasis-related circRNAs in cancer treatment. In summary, we briefly summarize the diverse roles of a circRNA-associated ceRNA network in cancer metastasis and the potential clinical application, especially the interaction of circRNA and miRNA/isomiR, which may complicate the RNA regulatory network and which will contribute to a novel insight into circRNA in the future.