CircRTN4IP1 regulates the malignant progression of intrahepatic cholangiocarcinoma by sponging miR-541-5p to induce HIF1A production

SNORD45A Affects Content of HIF-1α and Promotes Endothelial Angiogenic Function

To find out the differentially expressed small nucleolar RNAs (snoRNAs) in corneal neovascularization and their effect on angiogenesis. The rat model of corneal neovascularization induced by alkali burn was established, and the differentially expressed snoRNAs were sifted by high-throughput sequencing. Human genome homologs were screened and verified in cytopathological models. Polymerase chain reactions (PCRs) and Western blot assays were applied to detect mRNA and corresponding proteins affected by the differentially expressed snoRNA. In vitro, experiments were promoted to identify whether snoRNA affects endothelial cell migration and angiogenesis. Forty-seven differentially expressed snoRNAs were sifted from transparent cornea and neovascularization. According to sequencing and cytopathological model results, SNORD45A was selected for subsequent experiments. At mRNA and protein levels, SNORD45A affected the expression of HIF-1α. SNORD45A promoted endothelial angiogenesis through endothelial cell migration and tube formation regulation. The research suggested that SNORD45A partakes in the corneal neovascularization formation and can become one of the targets for corneal neovascularization therapy.

Hsa_circ_0050900 affects ferroptosis in intrahepatic cholangiocarcinoma cells by targeting hsa‑miR-605‑3p to regulate SLC3A2

Intrahepatic cholangiocarcinoma (ICC) is a highly lethal hepatobiliary tumor with high aggressiveness. The role of circular RNA (circRNA) in ICC remains to be explored. The present study aimed to investigate whether hsa_circ_0050900 affected ferroptosis in ICC cells by regulating hsa-microRNA (miR)-605-3p/solute carrier family 3 member 2 (SLC3A2). Human ICC cells were cultured and hsa_circ_0050900 expression was evaluated by reverse transcription-quantitative PCR. hsa_circ_0050900 was knocked down and ferroptosis inhibitor ferrostatin-1 was added to HuCCT-1 cells. Following knockdown or overexpression of hsa-miR-605-3p, Fe2+, reactive oxygen species (ROS), glutathione peroxidase 4 and SLC3A2 levels were assessed using iron and ROS assay kit or RT-qPCR and western blotting, respectively. Cell function experiments were performed to examine proliferation and migration abilities. Dual-luciferase reporter gene and argonaute2-RNA immunoprecipitation assay verified the relationship among hsa_circ_0050900, hsa-miR-605-3p, and SLC3A2. hsa_circ_0050900 was derived from actinin alpha 4 gene and was elevated in ICC cells. Among HuCCT-1, QBC-939, HCCC-9810, and RBE cell lines, the highest expression was in HuCCT-1 cells. Inhibition of hsa_circ_0050900 inhibited proliferation and migration by facilitating ICC cell ferroptosis. hsa-miR-605-3p expression was elevated after knocking down hsa_circ_0050900 and hsa-miR-605-3p was negatively regulated by hsa_circ_0050900. In addition, hsa-miR-605-3p targeted SLC3A2. Overexpression of hsa-miR-605-3p regulated SLC3A2 to promote ICC cell ferroptosis and inhibit proliferation and migration. Taken together, knockdown of hsa_circ_0050900 inhibited SLC3A2 expression via sponging hsa-miR-605-3p to promote ICC cell ferroptosis, and finally suppressed proliferation and migration. The present study suggested that hsa_circ_0050900 was a potential therapeutic target for ICC.

Hypoxia-induced circRTN4IP1 promotes progression and glycolysis of hepatocellular carcinoma cells

Hypoxia is one of the hallmarks of solid tumors, especially in hepatocellular carcinoma (HCC). CircRNAs are reported to be tightly connected to hypoxia and also have essential roles in cancer progression. However, many circRNAs implicated in hypoxia-mediated HCC progression are still unclear and require further exploration. In this study, a hypoxia cell model was structured by exposing cells to hypoxia conditions (1% O2) and normoxia conditions (21% O2) as a control. The effects of hypoxia and normoxia on cell viability, migration, invasion, and glycolysis were examined. The expressions of circRNARTN4IP1 under hypoxia were identified. Finally, molecular mechanisms and biological function of circRTN4IP1 were explored. We confirmed that hypoxia treatment facilitated capacities of proliferation, migration, invasion, and glycolysis in tumor cells. Hypoxia induced a significant increase expression of circRTN4IP1 in cells. Functionally, knockdown of circRTN4IP1 inhibited cell malignant progression and glycolysis under hypoxia HCC cells. Mechanistically, HIF1A targeted the promoter region of circRTN4IP1 and positively regulated the expression of circRTN4IP1. In addition, circRTN4IP1 targeted miR-532-5p/G6PC3 axis. In short, hypoxia induced activation of the HIF1A/circRTN4IP1/miR-532-5p/G6PC3 signaling axis, which promoted proliferation, migration, invasion, and glycolysis of HCC cells. This study may reveal a possible mechanism driving the progression of hypoxia HCC, so as to find potential effective candidates for targeting hypoxia microenvironment therapy.

Uncovering Candidate mRNAs, Signaling Pathways and Immune Cells in Atherosclerotic Plaque and Ischemic Stroke

Background

The specific molecular mechanistic link between atherosclerotic plaques and ischemic stroke (IS) is not clear. The aim of this study is to explore the potential molecular relationship between atherosclerotic plaques and IS.

Methods

All data were downloaded from the Gene Expression Omnibus (GEO) database. Key hub differentially expressed mRNAs (DEmRNAs) related to atherosclerotic plaques and IS were identified by differential expression analysis and least absolute shrinkage and selection operator (LASSO) analysis. Subsequently, a diagnostic model was established based on the expression of key hub DEmRNAs and logistic regression. In order to understand the molecular mechanism of key hub DEmRNAs, the transcription factor (TF) regulatory network and mRNA-miRNA-lncRNA regulatory network were also constructed. In addition, functional enrichment analysis and single-sample Gene Set Enrichment Analysis (ssGSEA) analysis were also performed.

Results

Four key hub DEmRNAs (ADCY3, CLDN7, PPM1B and RRAS2) were identified by differential expression analysis and LASSO analysis. Moreover, the diagnostic model based on four key hub DEmRNAs has excellent diagnostic accuracy. We also found that Type 1 T helper cell may be associated with IS caused by atherosclerosis based on ssGSEA analysis. In the mRNA-miRNA-lncRNA regulatory network, we found that multiple signaling axes such as RRAS2-hsa-miR-3150b-3p-ILF3-AS1, PPM1B-hsa-miR-541-5p-LINC00294, CLDN7-hsa-miR-184-LINC00467 and ADCY3-hsa-miR-488-3p-URB1-AS1 may play an important role in the progression of IS. In addition, some signaling pathways, including chemokine signaling pathway, MAPK signaling pathway and cAMP signaling pathway, may be involved in regulating IS.

Conclusion

The identified key molecules, signaling pathways and immune cells may help to provide a theoretical basis for exploring the relationship between atherosclerotic plaque and the progression of IS.

ALKBH5-induced circular RNA NRIP1 promotes glycolysis in thyroid cancer cells by targeting PKM2

Although circular RNAs (circRNAs) are involved in cell proliferation, differentiation, apoptosis, and invasion, the underlying regulatory mechanisms of circRNAs in thyroid cancer have not been fully elucidated. This article aimed to study the role of circRNA regulated by N6-methyladenosine modification in papillary thyroid cancer (PTC). Quantitative real-time PCR, western blotting, and immunohistochemistry were used to investigate the expressions of circRNA nuclear receptor-interacting protein 1 (circNRIP1) in PTC tissues and adjacent noncancerous thyroid tissues. In vitro and in vivo assays were carried out to assess the effects of circNRIP1 on PTC glycolysis and growth. The N6-methyladenosine mechanisms of circNRIP1 were evaluated by methylated RNA immunoprecipitation sequencing, luciferase reporter gene, and RNA stability assays. Results showed that circNRIP1 levels were significantly upregulated in PTC tissues. Furthermore, elevated circNRIP1 levels in PTC patients were correlated with high tumor lymph node metastasis stage and larger tumor sizes. Functionally, circNRIP1 significantly promoted glycolysis, PTC cell proliferation in vitro, and tumorigenesis in vivo. Mechanistically, circNRIP1 acted as a sponge for microRNA (miR)-541-5p and miR-3064-5p and jointly upregulated pyruvate kinase M2 (PKM2) expression. Knockdown of m⁶ A demethylase α-ketoglutarate-dependent dioxygenase alkB homolog 5 (ALKBH5) significantly enhanced circNRIP1 m⁶ A modification and upregulated its expression. These results show that ALKBH5 knockdown upregulates circNRIP1, thus promoting glycolysis in PTC cells. Therefore, circNRIP1 can be a prognostic biomarker and therapeutic target for PTC by acting as a sponge for oncogenic miR-541-5p and miR-3064-5p to upregulate PKM2 expression.

A review on the role of ncRNAs in the pathogenesis of cholangiocarcinoma

Cholangiocarcinoma is a rare tumor but a challenging cancer in terms of pathological changes, clinical manifestations and therapeutic options. Recent studies have provided evidence for participation of non-coding RNAs in the carcinogenic process of cholangiocarcinoma. We demonstrate the role of long non-coding RNAs, microRNAs and circular RNAs in the pathogenesis of cholangiocarcinoma and highlight their significant position as therapeutic targets and biomarkers for this type of cancer. We also list a number of molecular axes comprising these non-coding RNAs that represent potential targets for therapeutic options in cholangiocarcinoma, based on their significant roles in the regulation of cell proliferation, differentiation and apoptosis of these cells.

Exosomal circ-PTPN22 and circ-ADAMTS6 mark T cell exhaustion and neutrophil extracellular traps in Asian intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a liver tumor featured by challenges of non-invasive early diagnosis and a higher prevalence rate in Asian countries. These characteristics necessitate the development of liquid biopsy and immunotherapy methods to improve the prognosis of patients with ICC. Herein, we conducted a pilot study on the transcriptome of tumor tissues, adjacent normal tissues, and plasma exosomes of Asian patients with ICC from northern and southern China. We identified a subgroup of immunogenic Asian ICC, which is different from Caucasian ICC and is characterized by T cell exhaustion and neutrophil extracellular traps. The levels of circ-PTPN22 (hsa_circ_0110529) and circ-ADAMTS6 (hsa_circ_0072688), potential circRNA biomarkers, were elevated in the ICC tumor tissues and plasma exosomes of this subgroup than in the other subgroups and normal controls. These circRNAs were derived from post-transcriptional backsplicing of PTPN22 and ADAMTS6 that were expressed in T cells and endothelial cells, respectively, in the ICC microenvironment. Our results revealed a subgroup of Asian ICC characterized by T cell exhaustion and neutrophil extracellular traps and marked by elevated levels of circ-PTPN22 and circ-ADAMTS6 in tumor tissues and plasma exosomes. This subgroup is potentially detectable by plasma exosomal circRNAs and treatable with immune checkpoint blockade.

Hsa_circ_0019054 up-regulates HIF1A through sequestering miR-340-5p to promote the tumorigenesis of intrahepatic cholangiocarcinoma

BACKGROUND

Circular RNAs (circRNAs) have been uncovered to play an important regulatory function in the tumorigenesis of intrahepatic cholangiocarcinoma (ICC). Hsa_circ_0,019,054 was found to be increased in ICC. Here, we aimed to explore the action and mechanism of hsa_circ_0,019,054 in ICC carcinogenesis.

METHODS

Quantitative real-time PCR (qRT-PCR) and western blotting were used to detect the levels of genes and proteins. The functional experiments were performed using in vitro 5-ethynyl-2'-deoxyuridine (EdU) assay, cell counting Kit-8 (CCK-8) assay, flow cytometry, and in vivo murine xenograft model. The glycolysis was analyzed by detecting glucose uptake and lactate level. The binding between miR-340-5 p and hsa_circ_0,019,054 or HIF1A (Hypoxia-inducible factor 1-alpha) was validated using pull-down, dual-luciferase reporter and RNA immunoprecipitation assays.

RESULTS

Hsa_circ_0,019,054 expression was higher in ICC tissues and cells. Functionally, hsa_circ_0,019,054 silencing could suppress ICC cell proliferation and glycolysis active, as well as induce apoptosis. Mechanistically, hsa_circ_0,019,054 was demonstrated to act as a sponge for miR-340-5 p, which directly targeted HIF1A. Hsa_circ_0,019,054/miR-340-5 p/HIF1A formed a feedback loop. HIF1A was up-regulated, while miR-340-5 p was decreased in ICC tissues and cells. MiR-340-5 p re-expression attenuated ICC cell growth. Besides that, rescue experiments suggested that HIF1A overexpression or miR-340-5 p knockdown reversed the anti-proliferation and glycolysis arrest effects mediated by hsa_circ_0,019,054 silencing. Importantly, hsa_circ_0,019,054 silencing also impeded the growth of ICC in nude mice.

CONCLUSION

Hsa_circ_0,019,054 deficiency could attenuate the proliferation and glycolysis of ICC cells via miR-340-5 p/HIF1A axis.