miR-26b在放射性肺损伤中的作用及其机制的初步研究

发布时间：2018-04-01 19:32

本文选题：miR-26b　切入点：放射性肺损伤　出处：《重庆理工大学》2017年硕士论文

【摘要】：放射性肺损伤(Radiation-induced lung injury,RILI)是胸部肿瘤放疗后常见并发症之一,如肺癌、乳腺癌等癌症的放疗后。放射性肺损伤的早期主要表现为放射性肺炎,后期部分患者可发展为肺纤维化,严重影响患者的生活质量,并且明显缩短患者的生存时期。microRNA(miRNA)一直是近些年研究的热点。miRNA是一类内源性非编码小RNA分子,长度在18-22nt之间。miRNA的表达极为广泛,几乎包涵了所有的生物,如植物、动物和病毒等。目前miRNA的研究也较为深入,主要是在转录水平上调控基因的表达,它通过结合靶基因的3’非翻译区抑制翻译或增强靶mRNA的降解。人基因组中约60%的基因都受到miRNA的调控。近年来,越来越多研究表明电离辐射可以诱导miRNA差异表达,miRNA的异常表达可能与肿瘤细胞辐射敏感性具有一定的相关性。因此,miRNA可能作为一个潜在的新的放疗增敏靶点,有望在未来在临床上得到广泛应用。目前关于miRNA与放射性肺损伤之间的研究还不是很多,具体的生物学机制也不清楚。本课题是为了揭示miRNA与放射性肺损伤之间的关系,体外初步探讨miRNA对放射性肺损伤发生的影响及相关机制。作者通过查阅大量文献,发现microRNA-26b(miR-26b)可能是一个潜在的较为重要的miRNA,认为miR-26b可能在放射性肺损伤中发挥着非常重要的作用。作者采用人的支气管上皮细胞HBE作为细胞模型,暴露于不同的辐射剂量,发现电离辐射会显著上调miR-26b的表达水平;接着采用转染技术,在干扰HBE细胞中miR-26b的表达后重新暴露于电离辐射中;然后采用CCK8检测其对细胞增殖能力的影响,通过流式细胞术分析miR-26b转录抑制对HBE细胞周期分布的影响。实验结果表明:电离辐射暴露条件下会上调HBE细胞中miR-26b的表达水平;干扰HBE细胞miR-26的表达后,电离辐射会显著促进HBE细胞增殖,干扰miR-26b后暴露于电离辐射下会影响HBE细胞周期,阻滞在G2/M期;通过生物信息学分析,发现CCND2可能是miR-26b的靶基因,miR-26可以靶向负调控CCND2的表达。通过上述研究,作者发现miR-26b在体外参与对人支气管上皮细胞HBE增殖及放射敏感性的调控,其作用机制可能与其对细胞周期等相关蛋白的表达调控有关,然而具体的作用途径和分子机制还有待进一步的深入研究。
[Abstract]:Radiation pulmonary injury (Radiation-induced lung injury, RILI) is one of the common complications after radiotherapy of thoracic tumors, such as lung cancer, breast cancer and other cancers after radiotherapy. Early radiation-induced lung injury mainly for late radiation pneumonitis, some patients may develop pulmonary fibrosis, seriously affecting the quality of life of patients and shorten the survival of patients with.MicroRNA during the period of.MiRNA (miRNA) has been a hot research in recent years is a kind of endogenous non encoding small RNA molecules, the expression of 18-22nt in length.MiRNA is very wide, it covers almost all organisms, such as plants, animal and virus. At present the research on miRNA is also deeply, is mainly regulated at the transcriptional level of gene expression it is, by combining the target gene 3 'untranslated region inhibit translation or enhanced degradation of target mRNA. About 60% genes in the genome are regulated by miRNA in recent years. And more and more research shows that ionizing radiation can induce expression of miRNA, the radiation sensitivity of tumor cells and abnormal expression of miRNA has a certain correlation. Therefore, miRNA may serve as a potential new target for radiosensitization, is expected to be widely used in clinical applications. The future researches on miRNA and radiation induced lung injury there is not a lot, specific biological mechanism is not clear. This study is to reveal the relationship between miRNA and radiation-induced lung injury in vitro, preliminary study of miRNA on the phase and shutdown influence the occurrence of radiation-induced lung injury. The author by reading a lot of literature, found that microRNA-26b (miR-26b) is potentially an important miRNA and that miR-26b may play a very important role in radiation-induced lung injury. The bronchial epithelial cells HBE as model cells, exposure In different radiation doses, the expression level of miR-26b was significantly up-regulated by ionizing radiation will be found; then the transfection, expression of miR-26b in interference in HBE cells after exposure to ionizing radiation; then using CCK8 to detect the effect on cell proliferation, through the analysis of inhibition effect on HBE cell cycle distribution of miR-26b transcription by flow cytometry FCM. The experimental results show that exposure to ionizing radiation will increase the expression level of miR-26b in HBE cells under the condition of interfering HBE expression; miR-26 cells after ionizing radiation can significantly promote the proliferation of HBE cells, miR-26b interference after exposure to ionizing radiation will affect HBE cell cycle arrest in G2/M phase; by Bioinformatics analysis. We found that CCND2 may be the target gene of miR-26b, miR-26 can express the target to the negative regulation of CCND2. Through the above research, the author found that miR-26b in vitro in on human bronchial epithelial cells The regulation of HBE cell proliferation and radiosensitivity, expression regulation and its mechanism may be related to cell cycle related proteins, but the pathway and the exact molecular mechanism still needs further research.

【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R730.55

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