Huang Guangyi, Jiang Zeping, Zhu Wuan, Wu Zhiyue
Department of Urology Surgery, the Fourth Affiliated Hospital Zhejiang University School of Medicine, Shangcheng Dadao, Yiwu City, 322001, Zhejiang Province, China.
Biochem Genet. 2023 Feb;61(1):390-409. doi: 10.1007/s10528-022-10251-2. Epub 2022 Aug 5.
Circular RNA lysine demethylase 4A (circKDM4A) is also named circ_0012098 and its abnormal expression has been confirmed in serum exosomes of prostate cancer (PC) patients. However, whether PC progression involves the exosomal circ_0012098 remains unknown. RNA expression of circKDM4A, microRNA-338-3p (miR-338-3p) and cullin 4B (CUL4B) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by Western blot. The positive expression rate of nuclear proliferation marker (ki-67) was analyzed by immunohistochemistry assay. Dual-luciferase reporter assay and RNA immunoprecipitation assay were used to identify the interaction between miR-338-3p and circKDM4A or CUL4B. Mouse model assay was performed to determine the effect of exosomal circKDM4A on tumorigenesis in vivo. CircKDM4A expression was significantly upregulated in the serum exosomes from PC patients compared with the exosomes from healthy volunteers. Exosomes treatment promoted the proliferation, migration and invasion of PC cells but inhibited apoptosis; however, these effects were attenuated after circKDM4A knockdown. Meanwhile, circKDM4A depletion restored exosome-increased circKDM4A expression. Additionally, circKDM4A acted as a miR-338-3p sponge, and miR-338-3p bound to CUL4B in PC cells. CircKDM4A regulated the effect of exosome-induced PC cell malignancy by interacting with miR-338-3p and CUL4B. Moreover, circKDM4A silencing relieved exosome-induced tumor growth in vivo. Exosomal circKDM4A promoted PC malignant progression by the miR-338-3p/CUL4B axis, providing a therapeutic target for PC.
环状RNA赖氨酸去甲基化酶4A（circKDM4A）也被命名为circ_0012098，其异常表达已在前列腺癌（PC）患者的血清外泌体中得到证实。然而，PC进展是否涉及外泌体circ_0012098仍不清楚。通过定量实时聚合酶链反应检测circKDM4A、微小RNA-338-3p（miR-338-3p）和cullin 4B（CUL4B）的RNA表达。通过蛋白质印迹法检测蛋白质表达。通过免疫组织化学分析检测核增殖标志物（ki-67）的阳性表达率。采用双荧光素酶报告基因检测和RNA免疫沉淀检测来鉴定miR-338-3p与circKDM4A或CUL4B之间的相互作用。进行小鼠模型试验以确定外泌体circKDM4A对体内肿瘤发生的影响。与健康志愿者的外泌体相比，PC患者血清外泌体中circKDM4A表达显著上调。外泌体处理促进了PC细胞的增殖、迁移和侵袭，但抑制了细胞凋亡；然而，在circKDM4A敲低后，这些作用减弱。同时，circKDM4A缺失恢复了外泌体增加的circKDM4A表达。此外，circKDM4A充当miR-338-3p海绵，且miR-338-3p在PC细胞中与CUL4B结合。CircKDM4A通过与miR-338-3p和CUL4B相互作用来调节外泌体诱导的PC细胞恶性程度。此外，circKDM4A沉默减轻了体内外泌体诱导的肿瘤生长。外泌体circKDM4A通过miR-338-3p/CUL4B轴促进PC恶性进展，为PC提供了一个治疗靶点。
