miR-188-5p通过靶向PTEN激活PI3K/Akt信号通路增强鼻咽癌放射抵抗的机制研究

文献信息

中文摘要

背景： 放射抵抗仍然是鼻咽癌（NPC）治疗中的关键障碍，但其潜在机制尚未完全阐明。尽管miR-188-5p已被认为与多种肿瘤的恶性进展有关，但其在NPC放射抵抗中的作用仍需进一步研究。本研究旨在探讨miR-188-5p是否通过靶向PTEN激活PI3K/AKT信号通路并诱导上皮-间质转化（EMT）来介导放射抵抗。
方法： 建立放射抵抗NPC细胞系C666-1R。使用Cell Counting Kit-8（CCK-8）和集落形成实验评估细胞增殖和放射抵抗。将C666-1R细胞转染miR-188-5p抑制剂/模拟物和sh-PTEN，随后进行4 Gy照射。进行定量实时聚合酶链反应（qRT-PCR）、蛋白质印迹、Transwell实验、伤口愈合实验、流式细胞术和双荧光素酶报告基因实验，以评估miR-188-5p对细胞增殖、侵袭、迁移、凋亡以及PTEN/PI3K/AKT通路的影响。
结果： 成功建立并验证了放射抵抗NPC细胞系。miR-188-5p在NPC组织和NPC细胞系中高表达，尤其是在放射抵抗的C666-1R细胞中。抑制miR-188-5p增强了放射敏感性，表现为细胞活力、侵袭和迁移减少，以及凋亡增加。双荧光素酶报告基因实验证实miR-188-5p直接结合PTEN的3'-UTR并抑制其表达。救援实验表明，PTEN敲低逆转了miR-188-5p抑制诱导的PI3K/AKT活性和EMT表型抑制，恢复了p-PI3K、p-AKT、N-cadherin和Vimentin水平，同时下调了E-cadherin。这些发现表明，miR-188-5p通过直接靶向PTEN激活PI3K/AKT通路并促进EMT，从而介导NPC放射抵抗。
结论： miR-188-5p通过抑制PTEN表达，解除其对PI3K/AKT信号通路的负调控，激活该通路并诱导EMT，从而增强NPC细胞的放射抵抗。因此，抑制miR-188-5p可能是克服NPC放射抵抗的一种有前景的策略。

英文摘要

BACKGROUND: Radiotherapy resistance remains a critical obstacle in nasopharyngeal carcinoma (NPC) treatment, yet the underlying mechanisms are not fully understood. Although miR-188-5p has been implicated in the malignant progression of various tumors, its role in NPC radioresistance requires further investigation. This study aims to explore whether miR-188-5p mediates radioresistance by targeting PTEN to activate the PI3K/AKT signaling pathway and induce epithelial-mesenchymal transition (EMT).
METHODS: Radioresistant NPC cell lines C666-1R were established. Cell proliferation and radioresistance were evaluated using Cell Counting Kit-8 (CCK-8) and colony forming assays. C666-1R cells were transfected with miR-188-5p inhibitor/mimic and sh-PTEN, followed by 4 Gy irradiation. Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, Transwell assay, wound healing assay, flow cytometry, and dual-luciferase reporter assay were performed to assess the effects of miR-188-5p on cell proliferation, invasion, migration, apoptosis, and the PTEN/PI3K/AKT pathway.
RESULTS: Radioresistant NPC cell lines were successfully established and validated. miR-188-5p was highly expressed in NPC tissues and NPC cell lines, particularly in the radioresistant C666-1R cells. Inhibition of miR-188-5p enhanced radiosensitivity, as evidenced by reduced cell viability, invasion, migration, and increased apoptosis. Dual-luciferase reporter assay confirmed that miR-188-5p directly bound to the 3'-UTR of PTEN and suppressed its expression. Rescue experiments demonstrated that PTEN knockdown reversed the miR-188-5p inhibition-induced suppression of PI3K/AKT activity and EMT phenotype, restoring p-PI3K, p-AKT, N-cadherin, and Vimentin levels while downregulating E-cadherin. These findings indicate that miR-188-5p activates the PI3K/AKT pathway and promotes EMT by directly targeting PTEN, thereby mediating NPC radioresistance.
CONCLUSIONS: miR-188-5p enhances radioresistance in NPC cells by suppressing PTEN expression, relieving its negative regulation of the PI3K/AKT signaling pathway, activating this pathway, and inducing EMT. Thus, inhibiting miR-188-5p may represent a promising strategy to overcome radioresistance in NPC.