Yang Xiangdi, Zeng Xiaochun, Xia Nengxing, Xie Xuecheng, Long Yingjie
Department of Oncology, The First People's Hospital of Chenzhou, Chenzhou City, China.
Department of Nephrology, The First People's Hospital of Chenzhou, Chenzhou City, China.
J Biochem Mol Toxicol. 2025 May;39(5):e70263. doi: 10.1002/jbt.70263.
Many circular RNAs (circRNAs) are frequently expressed in cancers and involved in cancer progression. Clear cell renal cell carcinoma (ccRCC) is a malignancy with a high mortality rate. A previous study has shown that circ_0003520 is increased in ccRCC. However. The action of circ_0003520 in ccRCC progression and its possible mechanisms remain unclear. Levels of circ_0003520, miR-205-5p and cullin 4B (CUL4B) were examined by qRT-PCR and western blot. Cell counting kit-8 (CCK-8), 5-ethynyl-2' -deoxyuridine (EdU), flow cytometry, transwell, tube formation, and xenograft tumor assays were conducted to detect the effects of circ_0003520 on cRCC cell proliferation, apoptosis, migration, invasion, angiogenesis In Vitro, as well as tumor formation In Vivo. The binding between circ_0003520 or CUL4B and miR-205-5p was analyzed using dual-luciferase activity reporter assay and RNA immunoprecipitation (RIP) assay. We found that circ_0003520 and CUL4B expression was increased and miR-205-5p expression was decreased in ccRCC tissues compared to normal tissues. Circ_0003520 knockdown inhibited the proliferation, migration, invasion, and angiogenesis and promoted apoptosis in ccRCC cells in vitro, as well as inhibited tumor formation In Vivo. Further mechanism analysis showed that the miR-205-5p/CUL4B axis was the downstream target pathway of circ_0003520. Circ_0003520 could up-regulate CUL4B through sequestering miR-205-5p. Functionally, miR-205-5p inhibition or CUL4B overexpression could recover the inhibition mediated by circ_0003520 knockdown on ccRCC cell proliferation, migration, invasion, and angiogenesis, as well as the enhancement of cell apoptosis. Besides that, circ_0003520 also hindered tumor growth In Vivo via miR-205-5p/CUL4B axis. Circ_0003520 acts as an oncogene to promote ccRCC progression by regulating the miR-205-5p/CUL4B axis, indicating a promising strategy for suppressing ccRCC growth.
许多环状RNA（circRNAs）在癌症中频繁表达并参与癌症进展。肾透明细胞癌（ccRCC）是一种死亡率很高的恶性肿瘤。先前的一项研究表明，circ_0003520在ccRCC中表达增加。然而，circ_0003520在ccRCC进展中的作用及其可能机制仍不清楚。通过qRT-PCR和蛋白质免疫印迹法检测circ_0003520、miR-205-5p和cullin 4B（CUL4B）的水平。进行细胞计数试剂盒-8（CCK-8）、5-乙炔基-2'-脱氧尿苷（EdU）、流式细胞术、Transwell、管腔形成和异种移植肿瘤实验，以检测circ_0003520对ccRCC细胞增殖、凋亡、迁移、侵袭、血管生成的体外影响以及体内肿瘤形成情况。使用双荧光素酶活性报告基因检测法和RNA免疫沉淀（RIP）检测法分析circ_0003520或CUL4B与miR-205-5p之间的结合。我们发现，与正常组织相比，ccRCC组织中circ_0003520和CUL4B表达增加，miR-205-5p表达降低。敲低circ_0003520可抑制ccRCC细胞的体外增殖、迁移、侵袭和血管生成，并促进其凋亡，同时抑制体内肿瘤形成。进一步的机制分析表明，miR-205-5p/CUL4B轴是circ_0003520的下游靶标通路。circ_0003520可通过螯合miR-205-5p上调CUL4B。在功能上，抑制miR-205-5p或过表达CUL4B可恢复circ_0003520敲低介导的对ccRCC细胞增殖、迁移、侵袭和血管生成的抑制作用，以及对细胞凋亡的增强作用。除此之外，circ_0003520还通过miR-205-5p/CUL4B轴在体内阻碍肿瘤生长。circ_0003520作为一种癌基因，通过调节miR-205-5p/CUL4B轴促进ccRCC进展，为抑制ccRCC生长提供了一种有前景的策略。
