miR-19/p53/NF-κB调控双酚A促乳腺癌细胞增殖作用的分子机制及姜黄素的干预研究

BPA is closely associated with the development of breast cancer，while the underlying molecular mechanisms remain undefined. To date, no studies have been conducted yet to reveal the actions of miRNAs in BPA-mediated cancer development. In our preliminary studies we found that breast cancer cell proliferation induced by BPA corrected with up-regulation of miR-19a and miR-19b、deregulation of p53 and NF-κB , as well as changes in the expression of cyclin D1、PCNA、PTEN and p-AKT. However, the role and regulation of miR-19/p53/NF-κB network in cancer-promoting effects of BPA is totally unknown. Using breast cancer cell and nude mouse xenograft models, the proposed research will investigate the effects of BPA on miR-19a/19b expression and p53 and NF-κB signaling activity.　The role of miR-19a/19b in BPA-induced cell proliferation will be further explored via the determination of its cell growth-related target genes. The transcriptional regulation of miR-19a/19b by p53 and NF-κB will be examined with the measurements of DNA binding activity and transcriptional activity of 53 and NF-κB with miR-19 promoter, and by the alterations of miR-19 and its target gene expression with enforced over-expression or down-expression of these transcription factors. The negative modulation between 53 and NF-κB, alone with the feedback regulation of miR-19 on 53 and NF-κB, will also be explored. Moreover, this research will illustrate the role of miR-19/p53/NF-κB in the interventional effects of curcumin on BPA-induced breast cancer cell proliferation. Findings from this research will provide important new insights into the molecular mechanisms by which BPA exerts its breast cancer-promoting effect as well as its target intervention.

双酚A（BPA）与乳腺癌的发生发展密切相关，然其分子机制尚不明确。有关miRNA介导BPA的促癌作用及其机理目前未见任何研究报道。我们前期研究发现，BPA促乳腺癌细胞增殖作用与其上调miR-19a/19b和NF-κB 、抑制p53并影响细胞增殖相关基因表达有关; 然miR-19/p53/ NF-κB 在BPA促癌效应中的调控作用、调控机制迄今完全未知。本课题拟采用体外细胞模型和动物模型相结合的方法，在领域内创新性地探讨BPA对乳腺癌细胞miR-19a/19b表达的影响、miR-19细胞增殖靶基因及其作用、以及p53和NF-κB 对miR-19的转录调控与调控机理，并在此基础上研究miR-19/p53/NF-κB在姜黄素干预BPA促乳腺癌效应中的调控作用。旨在为探索BPA促乳腺癌作用的分子机制，进而开展以机制为导向、通过靶向作用于关键miRNA分子的干预研究提供重要的科学依据。

乳腺癌是女性最常见的恶性肿瘤。环境污染尤其是环境内分泌干扰物对乳腺癌具有重要影响。BPA作为生产量最大、使用最广泛、人类接触最频繁的环境内分泌干扰物，与乳腺癌的发生发展密切相关。miRNA是近年的研究热点领域。miRNAs通过对靶基因转录后水平的调控作用，在肿瘤的发生发展中发挥着重要的作用。然而到目前为止，有关miRNA与BPA介导的乳腺癌发生发展的相关研究尚无研究。姜黄素是天然存在的植物多酚类物质，具有化学预防和治疗多种肿瘤的潜能而广受关注。姜黄素通过对多种信号通路和活性分子的影响发挥抑癌作用，其中包括miRNA。但有关姜黄素如何调控miRNA而干预BPA的促乳腺癌作用的机制研究尚未见报道。本课题采用体外细胞模型，深入探讨了BPA对乳腺癌细胞miR-19a/19b表达的影响、miR-19的调控机理、以及p53和NF-κB 对miR-19的转录调控；在人群样本中进一步分析了BPA、miR-19/p53、与乳腺癌的相关性；并在此基础上研究了miR-19/p53/NF-κB在姜黄素干预BPA促乳腺癌效应中的调控作用。本研究发现BPA通过上调致癌性miR-19a和miR-19b表达、下调p53表达而呈现促癌效应；并首次提出p53是miR-19a/miR-19b的直接靶基因；p53通过与miR-17-92簇的启动子结合负向转录调控miR-19a/miR-19b表达，而NF-κB与miR-19a/miR-19b之间则存在正向调控作用；在人群样本中，BPA在癌组织中的浓度显著高于癌旁组织，BPA的水平与miR-19/p53的相关性也得到了验证；这些结果揭示了p53/NF-κB/miR-19网络在BPA促乳腺癌细胞增殖过程中发挥着重要的作用。本课题在以机制为导向的分子靶点干预实验研究中发现，姜黄素作为多靶点化学干预分子通过调节miR-19/PTEN/AKT/p53而显著有效地干预BPA诱导的乳腺癌细胞增殖。综上所述，本项目研究为阐明BPA诱导乳腺癌细胞增殖、分子机制和其关键靶点，从而为BPA促乳腺癌效应的靶向干预研究提供了重要的科学依据，具有重要的科学意义。