Fan Shanji, Cui Ying, Liu Yingjie, Li Yuehua, Huang Hong, Hu Zecheng
Department of Breast and Thyroid Surgery, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China.
College of Chemistry and Materials Science, Hengyang Normal University, Hengyang, Hunan, China.
Epigenetics. 2025 Dec;20(1):2482382. doi: 10.1080/15592294.2025.2482382. Epub 2025 Mar 27.
The incidence rate of breast cancer (BC) ranks first among female malignant tumors. Late-stage BC patients are at risk of death from distant metastasis. Circular RNAs (circRNAs) play an important function in cancer development. This study looked at the role of circMYH9 in BC. The nude mouse tumor-bearing experiment was used to verify the role of circMYH9 in regulating BC tumor growth in mice. Gene expression and protein amount were tested by qRT-PCR, western blot, and IHC. The pathological changes in tumor tissues were analyzed by HE staining. Cell viability, proliferation, migration, and invasion were assessed using CCK8, colony formation assay, wound healing assay, and Transwell assay, respectively. The interactions between circMYH9, SPAG6, and EIF4A3 were analyzed by RIP assay. CircMYH9 was significantly upregulated in BC, and its upregulated was related to poor prognosis. CircMYH9 silencing markedly impaired BC cell proliferation, migration, and invasion. Mechanistically, circMYH9 promoted the mRNA stability and expression of SPAG6 by recruiting EIF4A3. As expected, SPAG6 overexpression abrogated inhibition mediated by circMYH9 knockdown on BC cell malignant behaviors. In addition, circMYH9 knockdown inhibited PI3K/Akt signal pathway by increasing PTEN expression in BC cells, while was reversed by SPAG6 upregulation. PTEN inhibition abolished inhibition induced by circMYH9 downregulation on BC malignant progression. Moreover, circMYH9 silencing inhibited tumor growth in mice. CircMYH9 overexpression regulated the PTEN/PI3K/AKT pathway by increasing SPAG6 mRNA stability through recruiting EIF4A3, thereby promoting BC malignant progression.
乳腺癌（BC）的发病率在女性恶性肿瘤中位居首位。晚期BC患者存在因远处转移而死亡的风险。环状RNA（circRNAs）在癌症发展中发挥着重要作用。本研究探讨了circMYH9在BC中的作用。采用裸鼠荷瘤实验来验证circMYH9在调节小鼠BC肿瘤生长中的作用。通过qRT-PCR、蛋白质免疫印迹法和免疫组化法检测基因表达和蛋白量。采用苏木精-伊红（HE）染色分析肿瘤组织的病理变化。分别使用CCK8、集落形成实验、伤口愈合实验和Transwell实验评估细胞活力、增殖、迁移和侵袭能力。通过RNA免疫沉淀实验（RIP实验）分析circMYH9、精子相关抗原6（SPAG6）和真核翻译起始因子4A3（EIF4A3）之间的相互作用。CircMYH9在BC中显著上调，其上调与预后不良相关。CircMYH9沉默显著损害BC细胞的增殖、迁移和侵袭能力。机制上，circMYH9通过招募EIF4A3促进SPAG6的mRNA稳定性和表达。正如预期的那样，SPAG6过表达消除了circMYH9敲低对BC细胞恶性行为的抑制作用。此外，circMYH9敲低通过增加BC细胞中磷酸酶和张力蛋白同源物（PTEN）的表达来抑制磷脂酰肌醇-3激酶（PI3K）/蛋白激酶B（Akt）信号通路，而SPAG6上调可逆转这种作用。PTEN抑制消除了circMYH9下调对BC恶性进展的抑制作用。此外，circMYH9沉默抑制小鼠肿瘤生长。CircMYH9过表达通过招募EIF4A3增加SPAG6 mRNA稳定性来调节PTEN/PI3K/AKT信号通路，从而促进BC恶性进展。
