Circ_0008285 knockdown represses tumor development by miR-384/RRM2 axis in hepatocellular carcinoma

Overexpression of circZNF720 Inhibits Hepatocellular Carcinoma Progression by Regulating miR-421/MAPK9

Hepatocellular carcinoma (HCC) is characterized by high incidence, high death rate and poor long term prognosis. Abnormal expression of circular RNA (circRNA) has been demonstrated to be closely associated with malignant progression of HCC. However, the effect of circZNF720 on HCC is largely incompletely understood. This study sought to explore the effect of circZNF720 on the progression of HCC by CCK-8, transwell, and flow cytometry experiments. The prognosis of circZNF720 on patients was analyzed by Kaplan-Meier curve. Then, the regulatory mechanisms among circZNF720, miR-421, and MAPK9 were identified by qRT-PCR, dual-luciferase reporter assay, and RIP analysis, respectively. The outcomes of this study disclosed that circZNF720 was lowly expressed in HCC, and this low expression was strongly linked with a poor prognosis for HCC patients. Overexpression of circZNF720 inhibited the proliferation, migration, and invasion of cells, and increased the apoptosis of cells. Mechanistic studies revealed that circZNF720 targeted miR-421 and regulated the development of HCC by acting as a sponge for miRNAs. In addition, MAPK9 was a downstream target of miR-421, and circZNF720 introduction hampered HCC progression by upregulating MAPK9 expression through sponging miR-421. In conclusion, circZNF720 restrained HCC progression by targeting miR-421/MAPK9. This study provides a novel target for the treatment of HCC.

RRM2‑mediated Wnt/β‑catenin signaling pathway activation in lung adenocarcinoma: A potential prognostic biomarker

The present study aimed to investigate the role and mechanism of action of ribonucleotide reductase M2 (RRM2) in lung adenocarcinoma and its potential as a therapeutic target. Data of patients with lung adenocarcinoma from The Cancer Genome Atlas database were collected and analyzed to evaluate the potential of RRM2 as a biomarker. The expression of RRM2 was evaluated in the A549 cell line and its cisplatin-resistant A549/DDP cell line derivative by western blot and reverse transcription-quantitative PCR. The study also investigated cell proliferation and the mechanism by which RRM2 controls cellular cisplatin resistance using CCK-8 and colony-formation assays. In addition, cell migration was assessed using Transwell assays, and the cell cycle and apoptosis were examined using flow cytometry. RRM2 was highly expressed in lung adenocarcinoma and was associated with the clinical TMN stage. Functional enrichment analysis showed that RRM2 was enriched in the cell cycle. Immune cell infiltration analysis identified 12 types of immune cell that exhibited differences between patients expressing different levels of RRM2. Cellular assays revealed higher levels of RRM2 expression in A549/DDP cells than A549 cells, and its expression was induced by cisplatin. RRM2 knockdown decreased cell proliferation and migration, accelerated apoptosis and caused cell cycle arrest in the S-phase, increasing the sensitivity of A549 and A549/DDP cells to cisplatin through the Wnt/β-catenin signaling pathway. Overexpression of β-catenin reduced the effects of RRM2 knockdown on A549 cells. Lung adenocarcinoma growth may be influenced by RRM2 through the Wnt/β-catenin signaling pathway, suggesting a potential pathway for cancer progression.

Exosomal circ_0008285 in follicle fluid regulates the lipid metabolism through the miR-4644/ LDLR axis in polycystic ovary syndrome

PURPOSE

Exosomal circRNA, as an essential mediator of the follicular microenvironment, has been implicated in the etiological and pathobiological studies of polycystic ovarian syndrome (PCOS). This study aimed to determine abnormal circular RNA (circRNA) expression profiles in follicle fluid (FF) exosomes in patients with PCOS and identify the role of circ_0008285/microRNA (miR)-4644/low-density lipoprotein receptor (LDLR) axis in PCOS.

METHODS

Sixty-seven women undergoing IVF/ICSI, 31 PCOS patients and 36 non-PCOS patients were included in the cohort study. The circRNA expression profiles of FF exosomes in PCOS (n = 3) and control group (n = 3) were compared by RNA sequencing. In an additional cohort (PCOS:28 vs Control:33), the mRNA expression levels of four circRNAs from FF exosomes were further verified by qRT-PCR. Bioinformatic analysis and dual luciferase reporter gene assay verified the relationship between circ_0008285 and miR-4644 and between miR-4644 and LDLR. KGN cells were infected with sh-circ0008285 and transfected with miR-4644 mimic to verify their roles in lipid metabolism.

RESULTS

Four circRNAs showed significantly different expressions. Circ_0044234 was overexpressed in PCOS patients, while circ_0006877, circ_0013167 and circ0008285 were decreased in PCOS. Among four differentially expressed circRNAs, circ0008285 was enriched in lipoprotein particle receptor activity and cholesterol metabolism pathway by GO and KEGG pathway analyses. Luciferase assay confirmed the competing endogenous RNA (ceRNA) network circ_0008285/miR-4644 /LDLR. The intercellular experiments on circ_0008285 and its reduction in KGN cells showed that the consumption of circ_0008285 in exosomes could increase the expression of miR-4644 in recipient cells and inhibit the expression of LDLR, as well as increase free fatty acid secretion.

CONCLUSION

Circ_0008285 can combine with miR-4644 to promote the expression of LDLR and affect the cholesterol metabolism of ovarian granulosa cells in PCOS. Our findings revealed the ceRNA network of circ_0008285 and provided a new path to investigate lipid metabolism abnormalities in PCOS.

Inhibition of circular RNA ASPH reduces the proliferation and promotes the apoptosis of hepatic stellate cells in hepatic fibrosis

Circular RNAs (circRNAs) are a newly identified form of non-coding RNA that play a crucial role in various pathological processes. However, the expression profile and function of circRNAs in hepatic fibrosis (HF) remain largely unknown. In this study, we showed that a novel circRNA ASPH (circASPH) mediates HF by targeting the miR-139-5p/Notch1 axis. We investigated the expression profile of circRNAs in hepatocyte exosomes of mice with HF using circRNA-sequencing and found significant upregulation of circASPH. Loss- and gain-of-function analysis of circASPH was performed to assess its role in HF. Furthermore, we performed luciferase reporter assay, RNA pull-down, and fluorescence in situ hybridization analyses and confirmed that circASPH directly binds to miR-139-5p. We also found that circASPH was upregulated in liver fibrogenesis. Downregulation of circASPH expression inhibited hepatic stellate cell (HSC) activation and proliferation, induced apoptosis, and attenuated mouse liver fibrogenic injury. Mechanistically, circASPH directly targeted miR-139-5p to regulate the expression of Notch1 in HF. Thus, downregulation of circASPH may suppress the activation of HSCs and HF through the circASPH/miR-139-5p/Notch1 axis. Our findings indicated that circASPH may be a potential biomarker for HF diagnosis and therapy.