CircRNA NALCN acts as an miR-493-3p sponge to regulate PTEN expression and inhibit glioma progression

Construction of CDKN2A-related competitive endogenous RNA network and identification of GAS5 as a prognostic indicator for hepatocellular carcinoma

BACKGROUND

Competitive endogenous RNA (ceRNA) is an innovative way of gene expression modulation, which plays a crucial part in neoplasia. However, the intricacy and behavioral characteristics of the ceRNA network in hepatocellular carcinoma (HCC) remain dismal.

AIM

To establish a cyclin dependent kinase inhibitor 2A (CDKN2A)-related ceRNA network and recognize potential prognostic indicators for HCC.

METHODS

The mutation landscape of CDKN2A in HCC was first explored using the cBioPortal database. Differential expression analysis was implemented between CDKN2Ahigh and CDKN2Alow expression HCC samples. The targeted microRNAs were predicted by lncBasev3.0, and the targeted mRNAs were predicted by miRDB, and Targetscan database. The univariate and multivariate analysis were utilized to identify independent prognostic indicators.

RESULTS

CDKN2A was frequently mutated and deleted in HCC. The single-cell RNA-sequencing analysis revealed that CDKN2A participated in cell cycle pathways. The CDKN2A-related ceRNA network-growth arrest specific 5 (GAS5)/miR-25-3p/SRY-box transcription factor 11 (SOX11) was successfully established. GAS5 was recognized as an independent prognostic biomarker, whose overexpression was correlated with a poor prognosis in HCC patients. The association between GAS5 expression and methylation, immune infiltration was explored. Besides, traditional Chinese medicine effective components targeting GAS5 were obtained.

CONCLUSION

This CDKN2A-related ceRNA network provides innovative insights into the molecular mechanism of HCC formation and progression. Moreover, GAS5 might be a significant prognostic biomarker and therapeutic target in HCC.

New insights into the physiology and pathophysiology of the atypical sodium leak channel NALCN

Cell excitability and its modulation by hormones and neurotransmitters involve the concerted action of a large repertoire of membrane proteins, especially ion channels. Unique complements of coexpressed ion channels are exquisitely balanced against each other in different excitable cell types, establishing distinct electrical properties that are tailored for diverse physiological contributions, and dysfunction of any component may induce a disease state. A crucial parameter controlling cell excitability is the resting membrane potential (RMP) set by extra- and intracellular concentrations of ions, mainly Na+, K+, and Cl-, and their passive permeation across the cell membrane through leak ion channels. Indeed, dysregulation of RMP causes significant effects on cellular excitability. This review describes the molecular and physiological properties of the Na+ leak channel NALCN, which associates with its accessory subunits UNC-79, UNC-80, and NLF-1/FAM155 to conduct depolarizing background Na+ currents in various excitable cell types, especially neurons. Studies of animal models clearly demonstrate that NALCN contributes to fundamental physiological processes in the nervous system including the control of respiratory rhythm, circadian rhythm, sleep, and locomotor behavior. Furthermore, dysfunction of NALCN and its subunits is associated with severe pathological states in humans. The critical involvement of NALCN in physiology is now well established, but its study has been hampered by the lack of specific drugs that can block or agonize NALCN currents in vitro and in vivo. Molecular tools and animal models are now available to accelerate our understanding of how NALCN contributes to key physiological functions and the development of novel therapies for NALCN channelopathies.

Tumor-derived CircRNA_102191 promotes gastric cancer and facilitates M2 macrophage polarization

BACKGROUND

Gastric cancer is a common malignant tumor of the digestive tract and the fourth leading cause of death from cancer-related diseases. In recent years, many studies have found that circular RNAs play an important role in cancer. Tumor-associated macrophages (TAMs) are also critical for tumor progression.

OBJECTIVE

This study examined the role of circRNA_102191 in gastric cancer progression.

METHODS

The relative mRNA levels were determined by qRT-PCR. Western blotting and ELISA were used to detect the protein levels. In vitro proliferation was assessed using CCK8 and clonogenic assays. The migration and invasion of cell lines were assessed by transwell-based assays. The interactions between molecules were detected using a luciferase reporter assay. M0 macrophages were induced with PMA. M1 macrophages were induced with LPS and IFN-γ, and M2 macrophages were induced with IL-4.

RESULTS

The expression of circRNA_102191 was enhanced significantly in gastric cancer cell lines and clinical tumor tissues. CircRNA_102191 promotes gastric cancer cell progression by regulating miR-493-3p and its downstream target gene XPR1. CircRNA_102191 can enhance the EMT process of gastric cancer cells by promoting the M2 polarization of macrophages.

CONCLUSION

CircRNA_102191 promotes the biological function of gastric cancer cells by regulating the miR-493-3p/XPR1 axis and M2 macrophage polarization.

Propofol Suppresses Glioma Tumorigenesis by Regulating circ_0047688/miR-516b-5p/IFI30 Axis

Propofol has recently attracted increasing attention for its anti-tumor property in cancers, including glioma. Circular RNAs (circRNAs) can act as key regulators in various cancers. However, the relationship between propofol and circ_0047688 in glioma is still unclear. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and colony formation assays. Cell migration and invasion were determined using transwell assay. Cell apoptosis was detected by flow cytometry. Protein levels and RNA levels were detected by western blot assay and real-time quantitative polymerase chain reaction (RT‑qPCR), respectively. The intermolecular interaction was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay. A mouse xenograft model was established for in vivo experiments. Propofol inhibited cell proliferation, migration, and invasion and accelerated apoptosis in glioma cells. Circ_0047688 was upregulated in glioma tissues and cells, and propofol downregulated circ_0047688 in a dose-dependent manner. Circ_0047688 knockdown inhibited glioma cell progression and its overexpression abated the anti-tumor role of propofol in glioma cells. Moreover, miR-516b-5p was a direct target of circ_0047688, and circ_0047688 promoted glioma cell progression by sponging miR-516b-5p. In addition, IFI30 was a direct target of miR-516b-5p, and miR-516b-5p inhibited glioma cell malignant behaviors by targeting IFI30 in propofol-treated cells. Furthermore, circ_0047688 overexpression could weaken the anti-tumor role of propofol in vivo. Propofol inhibited glioma progression via modulating circ_0047688/miR-516b-5p/IFI30 axis, providing a potential therapeutic strategy for treatment of glioma.

Propofol-Induced miR-493-3p Inhibits Growth and Invasion of Gastric Cancer through Suppression of DKK1-Mediated Wnt/β-Catenin Signaling Activation

Purpose

Gastric cancer (GC) is one of the most common malignant tumors and also one of the most deadly tumors. In recent years, studies have shown that propofol can inhibit the proliferation and metastasis of many tumor cells. In the present study, we aimed to investigate the underlying mechanism of propofol inhibition of the growth and invasion of GC cells.

Methods

Human gastric cancer cell line SGC-7901 and human normal gastric epithelial cell GES-1 were cultured in high-glucose Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% fetal bovine serum at 37°C with 5% CO₂. Propofol of different concentrations (0, 2, 5, and 10 μg/mL) was used to treat SGC-7901, and miR-493-3p inhibitor was transfected into SGC-7901. The cell proliferation of SGC-7901 was analyzed by MTT as well as colony formation assay. The qRT-PCR was used to assess the expression of mRNA for key genes. We examined the protein expression of DKK1 and relative markers with western blot. Putative binding places of miR-493-3p on the 3'-untranslated area of DKK1 were predicted using bioinformatics and dual-luciferase method.

Results

Propofol prohibited phenotypic features of GC, according to our findings. Furthermore, research into the underlying mechanisms of propofol's suppressive effects in GC cell proved that propofol therapy improved the degrees of expression of the potential tumor suppressor miR-493-3p. The inhibiting properties of propofol on GC cell development, migration, and invasion were abolished when propofol-induced miR493-3p was silenced with anti-miR-493-3p. We also found that this drug reversed epithelial-mesenchymal transformation in SGC-7901 cells via inducing miR-493-3p. Propofol-induced miR-493-3p decreases GC cell development via targeting DKK1 and hence inhibits Wnt/β-catenin signaling, according to these findings.

Conclusion

Propofol-induced miR-493-3p decreased GC cell development via targeting DKK1 and hence inhibited Wnt/β-catenin signaling, according to these findings.

Circular RNAs as emerging players in cervical cancer tumorigenesis; A review to roles and biomarker potentials

Cervical cancer is the most lethal gynecological cancer among women worldwide. Most of the patients are diagnosed at the advanced stages due to late diagnosis and lack of accessible and valuable approaches for early detection of the disease. Circular RNAs (circRNAs) are a distinguishable class of non-coding RNAs with characteristic loop structures. Although their function has not been completely elucidated; however, recent evidence has suggested regulatory functions for circRNAs on gene expression controlling various biological functions like cell growth and apoptosis, development, embryogenesis, and pathogenesis of human diseases particularly cancers. Studies show the role of dysregulated circRNAs in biological processes including cell proliferation, migration, invasion, apoptosis, angiogenesis, and chemoresistance contributing to affect tumorigenesis in ovarian cancer cells, animal, and clinical studies. These effects can be defined as consistent with several tumorigenesis characteristics, which are defined as "hallmarks of cancer". Additionally, dysregulated circRNAs exhibit prognostic, and diagnostic potentials both in the prediction of prognosis in ovarian cancer patients, and also their discrimination from healthy individuals. Furthermore, targeting circRNAs has shown positive results in the suppression of malignant features of cancer cells, and also in overcoming chemoresistance. In this review, I have gathered the majority of studies evaluating the role of circRNAs in the development, and progression of cervical cancer, and also have discussed prognostic, diagnostic, and therapeutic potentials of circRNAs for clinical applications in cervical cancer patients.

Circular RNA circ-PLCD1 functions as a tumor suppressor in non-small cell lung cancer by inactivation of PI3K/AKT signaling pathway

Circular RNAs (circRNAs) are emerging as crucial regulators in tumorigenesis and aggressive progression. However, their biological roles in non-small cell lung cancer (NSCLC) remain largely unknown. Here, by performing circRNA high throughput sequencing in 4 paired NSCLC and normal tissues, we found a NSCLC-associated circRNA, circ-PLCD1, which was evidently downregulated in NSCLC tissues and cell lines. Circ-PLCD1 was transcriptionally activated by tumor-inhibiting protein p53, and exogenous expression of circ-PLCD1 inhibited NSCLC cell proliferation, invasion and induced apoptosis. Mechanistically, circ-PLCD1 acted as a competitive endogenous RNA (ceRNA) to sponge miR-375 and miR-1179 and elevate PTEN, a well-known inhibitor of oncogenic PI3K/AKT signaling, thereby repressing NSCLC tumorigenesis. Importantly, we also identified this ceRNA regulatory axis of circ-PLCD1/miR-375/miR-1179/PTEN in vivo by establishing a xenograft tumor model. Clinically, NSCLC patients with low circ-PLCD1 expression had larger tumor size, later clinical stage and shorter survival time than those with high circ-PLCD1 expression. Altogether, our findings reveal the important tumor suppressive role of circ-PLCD1 in NSCLC, reactivation of this circRNA may be considered as a novel therapeutic avenue for patient with NSCLC.

Research Progress on Circular RNA in Glioma

The discovery of circular RNA (circRNA) greatly complements the traditional gene expression theory. CircRNA is a class of non-coding RNA with a stable cyclic structure. They are highly expressed, spatiotemporal-specific and conservative across species. Importantly, circRNA participates in the occurrence of many kinds of tumors and regulates the tumor development. Glioma is featured by limited therapy and grim prognosis. Cancer-associated circRNA compromises original function or creates new effects in glioma, thus contributing to oncogenesis. Therefore, this article reviews the biogenesis, metabolism, functions and properties of circRNA as a novel potential biomarker for gliomas. We elaborate the expression characteristics, interaction between circRNA and other molecules, aiming to identify new targets for early diagnosis and treatment of gliomas.

Circular RNA Circ-0002570 Accelerates Cancer Progression by Regulating VCAN via MiR-587 in Gastric Cancer

BACKGROUND

Circular RNAs (circRNAs) are closely associated with the occurrences and progress of gastric cancer (GC). We aimed to delve into the function and pathological mechanism of Circular RNA-0002570 (circ-0002570) in GC progression.

METHODS

CircRNAs differentially expressed in GC were screened using bioinformatics technology. The expression of circ-0002570 was detected in GC specimens and cells via qRT-PCR, and the prognostic values of circ-0002570 were determined. The functional roles of circ-0002570 on proliferation, migration, and invasion in GC cells were explored in vitro and in vivo. Interaction of circ-0002570, miR-587, and VCAN was confirmed by dual-luciferase reporter assays, Western blotting, and rescue experiments.

RESULTS

Circ-0002570 expression was distinctly increased in GC tissues compared to adjacent normal specimens, and GC patients with higher circ-0002570 expressions displayed a short survival. Functionally, knockdown of circ-0002570 resulted in the inhibition of cell proliferation, migration, and invasion, and suppressed tumor growth in vivo. Mechanistically, miR-587 was sponged by circ-0002570. VCAN expression in NSCLC was directly inhibited by miR-587. Overexpression of circ-0002570 prevented VCAN from miR-587-mediated degradation and thus facilitated GC progression.

CONCLUSION

The circ-0002570-miR-587-VCAN regulatory pathway promoted the progression of GC. Our findings provided potential new targets for the diagnosis and therapy of GC.