Circular RNAs have been identified as vital regulators to regulate the development of human cancers, including cervical cancer. Therefore, this study was designed to clarify the underlying mechanism of circASAP1 in cervical cancer. The real-time quantitative PCR assay was applied to quantify the expression levels of circASAP1, microRNA (miR)-338-3p, and ribonuclease P and MRP subunit p25 (RPP25) in cervical cancer tissues and cells. The cell proliferation ability was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide and colony-forming assays. The protein expression levels of cyclin D1, proliferating cell nuclear antigen, and RPP25 were assessed by western blot assay. Flow cytometry assays were used to determine the apoptosis and cell cycle distribution of cervical cancer cells. The transwell assay was employed to test the migration and invasion abilities of cervical cancer cells. The interaction relationship between miR-338-3p and circASAP1 or RPP25 was confirmed by dual-luciferase reporter assay and RNA pull-down assay. The xenograft experiment was established to clarify the functional role of circASAP1 inhibition in vivo. CircASAP1 was overexpressed in cervical cancer tissues and cells compared with negative groups. Additionally, the loss-of-functional experiments implied that knockdown of circASAP1 impeded proliferation, migration, and invasion while induced apoptosis and cell cycle arrest in cervical cancer cells along with repressed tumor growth in vivo through regulation of miR-338-3p. In addition, RPP25 was a target mRNA of miR-338-3p, and overexpression of miR-338-3p suppressed proliferation, migration, and invasion while induced apoptosis and cell cycle arrest in cervical cancer cells by suppressing RPP25 expression. Mechanistically, circASAP1 could function as a sponge for miR-338-3p to increase the expression of RPP25, and further regulated proliferation, migration, invasion, apoptosis, and cell cycle program of cervical cancer cells, which might be potential markers for cervical cancer diagnosis.

中文翻译：

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CircASAP1 通过海绵 miR-338-3p 上调 RPP25 促进宫颈癌的发展。

环状RNA已被确定为调节人类癌症（包括宫颈癌）发展的重要调节因子。因此，本研究旨在阐明circASAP1在宫颈癌中的潜在机制。采用实时定量PCR测定宫颈癌组织和细胞中circASAP1、microRNA (miR)-338-3p、核糖核酸酶P和MRP亚基p25 (RPP25)的表达水平。通过3-(4,5-二甲基噻唑-2-基)-2,5-二苯基-2H-四唑-3-溴化鎓和集落形成测定来测量细胞增殖能力。通过蛋白质印迹法评估细胞周期蛋白D1、增殖细胞核抗原和RPP25的蛋白表达水平。采用流式细胞术测定宫颈癌细胞的凋亡和细胞周期分布。采用Transwell实验检测宫颈癌细胞的迁移和侵袭能力。通过双荧光素酶报告基因测定和RNA Pull-down测定证实了miR-338-3p与circASAP1或RPP25之间的相互作用关系。建立异种移植实验以阐明体内circASAP1抑制的功能作用。与阴性组相比，CircASAP1在宫颈癌组织和细胞中过度表达。此外，功能丧失实验表明，敲低 circASAP1 会阻碍增殖、迁移和侵袭，同时诱导宫颈癌细胞凋亡和细胞周期停滞，并通过调节 miR-338-3p 抑制体内肿瘤生长。此外，RPP25是miR-338-3p的靶mRNA，miR-338-3p的过表达抑制增殖、迁移和侵袭，同时通过抑制RPP25表达诱导宫颈癌细胞凋亡和细胞周期停滞。从机制上讲，circASAP1可以作为miR-338-3p的海绵，增加RPP25的表达，并进一步调节宫颈癌细胞的增殖、迁移、侵袭、凋亡和细胞周期程序，这可能是宫颈癌诊断的潜在标志物。