Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
Asian Pac J Cancer Prev. 2021 Jan 1;22(1):305-313. doi: 10.31557/APJCP.2021.22.1.305.
MicroRNAs (miRNAs) expression has deregulated in several cancer types including breast cancer (BC). The present study aims at investigating the role, mechanism, clinical value of let-7d and miR-185 in BC, and the possible correlation these miRNAs with Rab25.
Tumor samples as well adjacent normal tissues (ANT) were acquired from fresh surgical specimens from 110 patients and the expression levels of let-7d, miR-185, Rab25, and snail were evaluated using real-time PCR. The immunohistochemical (IHC) process and western blot were done to detect the level of Rab25 and Snail protein expression in BC samples.
By comparing miRNAs expression profiles in clinical tissues of 110 patients using real-time PCR, let-7d, and miR-185 expression were dramatically downregulated in BC tissues (P < 0.05). Tumor size, stage, and lymph node metastasis were significantly related to miRNAs expression. Based on qRT-PCR and bioinformatics database analyses, we also recognized Rab25 as a possible target of miR-185 and let-7d. Rab25 expression was enhanced in BC cells and associated inversely with the expression level of mentioned miRNAs. qRT-PCR, immunohistochemistry, and western blot studies verified that Rab25 upregulation increased the levels of the snail, that key transcription factor of epithelial-mesenchymal transition (EMT).
These findings demonstrated that let-7d and miR-185 inhibited EMT by targeting Rab25 expression in BC. Therefore, targeting the let-7d and miR-185/Rab25 interaction may offer new therapeutic opportunities for treating BC patients.
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微小 RNA（miRNAs）在包括乳腺癌（BC）在内的几种癌症类型中的表达失调。本研究旨在探讨 let-7d 和 miR-185 在 BC 中的作用、机制、临床价值，以及这些 miRNA 与 Rab25 的可能相关性。
材料和方法：从 110 例患者的新鲜手术标本中获得肿瘤样本以及相邻正常组织（ANT），并使用实时 PCR 评估 let-7d、miR-185、Rab25 和 snail 的表达水平。免疫组织化学（IHC）过程和 Western blot 用于检测 BC 样本中 Rab25 和 Snail 蛋白表达水平。
结果：通过使用实时 PCR 比较 110 例患者临床组织中的 miRNA 表达谱，发现 let-7d 和 miR-185 在 BC 组织中表达显著下调（P <0.05）。肿瘤大小、分期和淋巴结转移与 miRNA 表达显著相关。基于 qRT-PCR 和生物信息学数据库分析，我们还发现 Rab25 可能是 miR-185 和 let-7d 的一个潜在靶点。Rab25 在 BC 细胞中表达增强，与上述 miRNA 的表达水平呈负相关。qRT-PCR、免疫组织化学和 Western blot 研究证实，Rab25 的上调增加了 snail 的水平，snail 是上皮-间充质转化（EMT）的关键转录因子。
结论：这些发现表明，let-7d 和 miR-185 通过靶向 Rab25 在 BC 中的表达抑制 EMT。因此，针对 let-7d 和 miR-185/Rab25 相互作用可能为治疗 BC 患者提供新的治疗机会。
