Hsa_circ_0039569 facilitates the progression of endometrial carcinoma by targeting the miR-197/high mobility group protein A1 axis

circRNAs in Endometrial Cancer-A Promising Biomarker: State of the Art

Endometrial cancer (EC) is one of the most common malignant tumors among women in the 21st century, whose mortality rate is increasing every year. Currently, the diagnosis of EC is possible only after a biopsy. However, it is necessary to find a new biomarker that will help in both the diagnosis and treatment of EC in a non-invasive way. Circular RNAs (circRNAs) are small, covalently closed spherical and stable long non-coding RNAs (lncRNAs) molecules, which are abundant in both body fluids and human tissues and are expressed in various ways. Considering the new molecular classification of EC, many studies have appeared, describing new insights into the functions and mechanisms of circRNAs in EC. In this review article, we focused on the problem of EC and the molecular aspects of its division, as well as the biogenesis, functions, and diagnostic and clinical significance of circRNAs in EC.

Propofol inhibits the proliferation, invasion, migration, and angiogenesis of oral squamous cell carcinoma through circ_0008898-mediated pathway

Propofol has been shown to inhibit oral squamous cell carcinoma (OSCC) progression. However, it is not clear whether propofol mediates OSCC progression through regulating circular RNA (circRNA) network. Quantitative real-time PCR was used to detect circ_0008898, miR-545-3p, and CT10 regulator of kinase-like protein (CRKL) expression. Cell functions were determined using CCK8 assay, Edu staining, MTT assay, transwell assay, wound healing assay, tube formation assay, and flow cytometry. Protein levels were examined by western blot analysis. RNA interaction was confirmed by dual-luciferase reporter assay and RIP assay. Our data showed that propofol repressed OSCC cell proliferation, invasion, migration, angiogenesis, and promoted apoptosis. circ_0008898 was highly expressed in OSCC, and its expression could be decreased by propofol. circ_0008898 silencing aggravated the suppressive effect of propofol on OSCC progression. In the mechanism, circ_0008898 could target miR-545-3p to positively regulate CRKL. MiR-545-3p inhibitor abolished the regulation of circ_0008898 silencing on propofol-mediated OSCC cell progression. MiR-545-3p inhibited the progression of propofol-treated OSCC cells, and this effect was reversed by CRKL overexpression. Also, circ_0008898 knockdown reduced OSCC tumor growth by regulating miR-545-3p/CRKL. In conclusion, propofol suppressed OSCC progression, which was achieved through regulating the circ_0008898/miR-545-3p/CRKL axis.

Circ_UBAP2 exacerbates proliferation and metastasis of OS via targeting miR-665/miR-370-3p/HMGA1 axis

Circ_UBAP2 is extensively engaged in regulating the development of various malignancies, containing osteosarcoma (OS). However, its biological significance and function are not fully understood. In this study, we found that circ_UBAP2 and HMGA1 levels were up-regulated, and miR-370-3p and miR-665 expressions were decreased in osteosarcoma tissues. Inhibition of circ_UBAP2 or HMGA1 expression in OS cells, cell viability, invasion and migration abilitities were notably hindered, and cell apoptosis abilities were increased. Bioinformatics analysis predicted that miR-665 and miR-370-3p were the downstream targets of circ_UBAP2, and the dual luciferase experiment demonstrated the correlation between them. In addition, inhibition of miR-665 and miR-370-3p expression could significantly reverse the impact of knocking down circ_UBAP2 on OS cells. HMGA1 was discovered to become the downstream target of both miR-665 and miR-370-3p. It was shown that over-expression of miR-665 or miR-370-3p notably stimulated the cell growth, invasion, and migration of osteosarcoma cells, while hindered cell apoptosis. Nevertheless, this effect could be reversed by concurrent over-expression of HMGA1. Our data strongly prove that circ_UBAP2 makes a vital impact on promoting the proliferation, invasion as well as migration of osteosarcoma cells via down-regulating the level of miR-665 and miR-370-3p, and later up-regulating the level of HMGA1. In conclusion, circ_UBAP2 is upregulated in osteosarcoma, and it competitively adsorbs miR-370-3p and miR-665, resulting in up-regulation of HMGA1, thus promoting OS development.

Circ_0039569 contributes to the paclitaxel resistance of endometrial cancer via targeting miR-1271-5p/PHF6 pathway

Circular RNA (circRNA) has been confirmed to be involved in the chemoresistance process of cancers. However, whether circ_0039569 mediates the chemoresistance of endometrial cancer (EC) remains unclear. Quantitative real-time PCR was performed to analyze circ_0039569, microRNA (miR)-1271-5p and PHD finger protein 6 (PHF6) expression. Cell counting kit-8 assay was used to assess the paclitaxel (PTX) resistance of cells. Cell proliferation, apoptosis and invasion were determined using EdU assay, colony formation assay, flow cytometry and transwell assay. Protein expression was examined by western blot analysis. RNA interaction was verified by dual-luciferase reporter assay and RNA pull-down assay. Xenograft tumor models were constructed to explore the effect of circ_0039569 knockdown on the PTX sensitivity of EC tumors. Circ_0039569 was upregulated in PTX-resistant EC tissues and cells. Knockdown of circ_0039569 enhanced the PTX sensitivity of EC cells by inhibiting cell growth and invasion. MiR-1271-5p could be sponged by circ_0039569, and its inhibitor abolished the regulation of circ_0039569 knockdown on the PTX sensitivity of EC cells. PHF6 was targeted by miR-1271-5p, and its overexpression eliminated the promotion effect of miR-1271-5p on the PTX sensitivity of EC cells. Also, interference of circ_0036569 enhanced the PTX sensitivity of EC tumors by regulating the miR-1271-5p/PHF6 pathway. Collectively, circ_0039569 might contribute to the PTX resistance of EC through the regulation of the miR-1271-5p/PHF6 axis.

Circular RNA_0001187 participates in the regulation of ulcerative colitis development via upregulating myeloid differentiation factor 88

Circular RNA (circRNA) had been confirmed to participate in ulcerative colitis (UC) development. Circular RNA_0001187 (Circ_0001187) had been found to be overexpressed in patients with Crohn disease. Therefore, circ_0001187 might be an important circRNA regulating intestinal inflammatory diseases. However, the role and mechanism of circ_0001187 in UC progression remains unclear. The colonic mucosal tissues were obtained from 23 UC patients and 23 healthy normal controls. Tumor necrosis factor-α (TNF-α) was used to mimic UC cell model in vitro. Cell function was assessed by cell counting kit 8 assay, EdU assay, flow cytometry, ELISA assay and oxidative stress detection. RNA interaction was confirmed by dual-luciferase reporter assay and RIP assay. Serum exosomes were isolated by ultracentrifugation and identified by transmission electron microscope. Circ_0001187 was overexpressed in UC patients. Circ_0001187 knockdown enhanced the proliferation, while suppressed apoptosis, inflammation and oxidative stress of TNF-α-induced FHC cells. Circ_0001187 acted as miR-1236-3p sponge, and the effects of circ_0001187 downregulation on TNF-α-induced FHC cell injury were overturned by miR-1236-3p inhibitor. MYD88 was targeted by miR-1236-3p, and circ_0001187 sponged miR-1236-3p to regulate MYD88. MYD88 knockdown alleviated TNF-α-induced FHC cell injury, and its upregulation revoked the inhibition effect of miR-1236-3p on TNF-α-induced FHC cell injury. High expression of circ_0001187 also was observed in the serum exosomes of UC patients. Our data confirmed that circ_0001187 facilitated UC progression through miR-1236-3p/MYD88 axis, which might be a potential treatment and diagnosis biomarker for UC.