Cancer Molecular Pathology, School of Medicine and Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, 4222, Australia.
Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi, 6205, Bangladesh.
Endocrine. 2017 Oct;58(1):153-166. doi: 10.1007/s12020-017-1393-3. Epub 2017 Aug 24.
This study aims to determine the expression of miR-34b-5p in thyroid carcinomas and to investigate the role of miR34b-5p in the modulation of proteins involved in angiogenesis of thyroid carcinoma cells.
The expressions of miR-34b-5p levels in five cell lines and 65 tissue samples from thyroid carcinomas were examined by real-time polymerase chain reaction. An exogenous miR-34b-5p (mimic) transiently overexpress miR-34b-5p in theses thyroid carcinoma cells. The effects of miR-34b-5p overexpression on the proteins involved in angiogenesis and cell cycle regulations (VEGF-A, Bcl-2 and Notch1) were investigated by Western blot, immunofluorescence, enzyme-linked immunosorbent assay followed by cell cycle analysis and apoptosis assays.
miR-34b-5p is markedly downregulated in all thyroid carcinoma cell lines and tissues samples when compared with non-neoplastic immortalised thyroid cell line and non-neoplastic thyroid tissues, respectively. The expression levels of miR-34b were significantly associated with T-stages of thyroid carcinomas (p = 0.042). Downregulation of VEGF-A, Bcl-2 and Notch1 proteins in thyroid carcinoma cells were noted in cells that transiently transfected with miR-34b-5p mimic. In addition, enzyme-linked immunosorbent assay confirmed the decreased expression of VEGF in thyroid carcinoma cells after transfection with miR-34b-5p mimic. Furthermore, miR-34b-5p mimic transfection induces significant accumulation of cells in G0-G1 of the cell cycle by blocking of their entry into the S transitional phase as well as increasing the total apoptosis.
miR-34b-5p functions as a potent regulator of angiogenesis, apoptosis and cell proliferation via modulation of VEGF-A, Bcl-2 and Notch1 proteins. It could be a target for developing treatment strategies of thyroid carcinoma with aggressive clinical behaviour.
本研究旨在探讨 miR-34b-5p 在甲状腺癌中的表达，并研究 miR34b-5p 在调节甲状腺癌细胞血管生成相关蛋白中的作用。
通过实时聚合酶链反应检测 5 种细胞系和 65 例甲状腺癌组织中 miR-34b-5p 水平的表达。这些甲状腺癌细胞中转染外源性 miR-34b-5p（模拟物）瞬时过表达 miR-34b-5p。通过 Western blot、免疫荧光、酶联免疫吸附试验，随后进行细胞周期分析和凋亡试验，研究 miR-34b-5p 过表达对血管生成和细胞周期调节相关蛋白（VEGF-A、Bcl-2 和 Notch1）的影响。
与非肿瘤性永生化甲状腺细胞系和非肿瘤性甲状腺组织相比，所有甲状腺癌细胞系和组织样本中 miR-34b-5p 的表达均明显下调。miR-34b-5p 的表达水平与甲状腺癌的 T 分期显著相关（p=0.042）。在瞬时转染 miR-34b-5p 模拟物的甲状腺癌细胞中，VEGF-A、Bcl-2 和 Notch1 蛋白的表达明显下调。此外，酶联免疫吸附试验证实，转染 miR-34b-5p 模拟物后，甲状腺癌细胞中 VEGF 的表达降低。此外，miR-34b-5p 模拟物转染通过阻断其进入 S 期过渡阶段，使细胞周期中 G0-G1 期的细胞显著积累，并增加总凋亡，从而诱导细胞显著凋亡。
miR-34b-5p 通过调节 VEGF-A、Bcl-2 和 Notch1 蛋白，作为血管生成、凋亡和细胞增殖的有效调节因子。它可能是开发具有侵袭性临床行为的甲状腺癌治疗策略的靶点。
