Circ_0000620 acts as an oncogenic factor in gastric cancer through regulating MMP2 expression via sponging miR-671-5p

METTL3 -mediated m6A modification of circ_0000620 regulates cisplatin sensitivity and apoptosis in lung adenocarcinoma via the MiR-216b-5p/KRAS axis

Circular RNAs (circRNAs) are stable non-coding RNAs characterized by the absence of the conventional 5' cap and 3' polyadenylated tail structure. Its involvement in various aspects of cancers underscores its significance in oncology. Elevated expression of circ_0000620 was observed in both lung adenocarcinoma (LUAD) tissues and cell lines. In vitro, experiments demonstrated that the downregulation of circ_0000620 increased cisplatin sensitivity and promoted cell apoptosis while suppressing malignant characteristics such as cell migration and proliferation. Further investigation into the mechanism underlying the increased expression of circ_0000620 revealed that Methyltransferase 3, N6-Adenosine-Methyltransferase Complex Catalytic Subunit (METTL3) mediates the m6A methylation modification of circ_0000620, thereby promoting its stability and expression. Furthermore, circ_0000620 modulates the miR-216b-5p/KRAS axis to influence apoptosis and cisplatin sensitivity in both A549 and H1299 cell lines. These findings were corroborated by in vivo nude mouse experiments, which showed that knockdown of circ_0000620 inhibited tumor growth and proliferation. In summary, METTL3 plays a role in regulating the stability of circ_0000620 expression, and circ_0000620 exerts its effects on LUAD apoptosis and cisplatin sensitivity through the miR-216b-5p/KRAS signaling pathway.

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.

A review on the role of miR-671 in human disorders

miR-671 is encoded by a gene on 7q36.1 and contributes to the pathogenesis of a variety of disorders, including diverse types of cancers, atherosclerosis, ischemic stroke, liver fibrosis, osteoarthritis, Parkinson's disease, rheumatoid arthritis, acute myocardial infarction and Crohn's disease. In the context of cancer, different studies have revealed opposite roles for this miRNA. In brief, it has been shown to be down-regulated in pancreatic ductal carcinoma, ovarian cancer, gastric cancer, osteosarcoma, esophageal squamous cell carcinoma and myelodysplastic syndromes. Yet, miR-671 has been up-regulated in glioma, colorectal cancer, prostate cancer and hepatocellular carcinoma. Studies in breast, lung and renal cell carcinoma have reported inconsistent results. The current review aims at summarization of the role of miR-671 in these disorders focusing on its target mRNA in each context and dysregulated signaling pathways. We also provide a summary of the role of this miRNA as a prognostic factor in malignancies.

Mechanism underlying circRNA dysregulation in the TME of digestive system cancer

Circular RNAs (circRNAs) are a new series of noncoding RNAs (ncRNAs) that have been reported to be expressed in eukaryotic cells and have a variety of biological functions in the regulation of cancer pathogenesis and progression. The TME, as a microscopic ecological environment, consists of a variety of cells, including tumor cells, immune cells and other normal cells, ECM and a large number of signaling molecules. The crosstalk between circRNAs and the TME plays a complicated role in affecting the malignant behaviors of digestive system cancers. Herein, we summarize the mechanisms underlying aberrant circRNA expression in the TME of the digestive system cancers, including immune surveillance, angiogenesis, EMT, and ECM remodelling. The regulation of the TME by circRNA is expected to be a new therapeutic method.