Li Yan, Wang Liang, Zhang Nan, Xu Yan
Department of Hematology, Tianjin Fourth Central Hospital, The Fourth Central Hospital Affiliated to Nankai University, The Fourth Central Clinical College, Tianjin Medical University, Tianjin City, China.
Histol Histopathol. 2023 May;38(5):525-536. doi: 10.14670/HH-18-466. Epub 2022 May 10.
Circular RNAs (circRNAs) are key players in tumorigenesis progression. However, the role and molecular mechanisms of circKCNQ5 in multiple myeloma (MM) progression remain unclear.
The quantitative real-time polymerase chain reaction was used for examining circKCNQ5, miR-335-5p, and Bromodomain-containing protein 4 (BRD4) levels. The proliferation ability of MM cells was determined by Cell Counting Kit-8 and colony-forming assays. The migration and invasion were analyzed by transwell assay. Flow cytometry was used to assess cell apoptosis. The lactate production, glucose consumption, and ATP/ADP ratios were determined by commercialized kits. The protein levels were quantified by western blot analysis. The interactions between circKCNQ5 and miR-335-5p, along with miR-335-5p and BRD4 were analyzed by dual-luciferase reporter and RNA immunoprecipitation assays.
The overexpression of circKCNQ5 was confirmed in MM tissues and cells. Importantly, knockdown of circKCNQ5 suppressed proliferation, migration, invasion, and glycolysis while it increased apoptosis of MM cells in vitro. Interestingly, the downregulation of miR-335-5p was able to rescue the circKCNQ5 inhibition-induced effects on MM cells. MiR-335-5p interacted with circKCNQ5, and was able to target BRD4 in MM cells. MiR-335-5p upregulation inhibited malignant phenotypes of MM cells depending on BRD4.
CircKCNQ5 was found to stimulate MM progression through competitively sponging to miR-335-5p.
环状RNA（circRNAs）是肿瘤发生发展的关键因素。然而，circKCNQ5在多发性骨髓瘤（MM）进展中的作用及分子机制仍不清楚。
采用定量实时聚合酶链反应检测circKCNQ5、miR-335-5p和含溴结构域蛋白4（BRD4）的水平。通过细胞计数试剂盒-8和集落形成试验测定MM细胞的增殖能力。采用Transwell试验分析细胞的迁移和侵袭能力。通过流式细胞术评估细胞凋亡。使用商业化试剂盒测定乳酸生成、葡萄糖消耗和ATP/ADP比值。通过蛋白质免疫印迹分析定量蛋白质水平。采用双荧光素酶报告基因和RNA免疫沉淀试验分析circKCNQ5与miR-335-5p以及miR-335-5p与BRD4之间的相互作用。
在MM组织和细胞中证实了circKCNQ5的过表达。重要的是，敲低circKCNQ5可抑制体外MM细胞的增殖、迁移、侵袭和糖酵解，同时增加细胞凋亡。有趣的是，miR-335-5p的下调能够挽救circKCNQ5抑制对MM细胞的影响。miR-335-5p与circKCNQ5相互作用，并能够在MM细胞中靶向BRD4。miR-335-5p的上调依赖于BRD4抑制MM细胞的恶性表型。
发现circKCNQ5通过竞争性结合miR-335-5p促进MM进展。
