前列腺癌循环miR410*调控树突状细胞抗肿瘤生物学作用的研究

A large number of specific microRNAs (miRNAs) involve in both occurrence and development of prostate cancer. Specific miRNA expression profiles have been found and analyzed in peripheral blood of prostate cancer patients. However, the role of circulating miRNA remains elusive. Our previous studies found that peripheral blood of prostate cancer patients and supernatants of prostate cancer cell contained a large number of miR410*. Meanwhile, high expression of miR410, the sequence-complementary miRNA of miR410*, was also found in dendritic cells (DCs) stimulated by prostate cancer cells debris (used as cancer antigens). The expression could be suppressed by incubating the stimulated DCs with supernatants of prostate cancer cells or transfecting them with miR410* mimics. Our study takes circulating miR410* as the starting point and will be unfolded in three aspects: (1) The molecular mechanism of miR410* high expression in prostate cancer cells; (2) The molecular mechanism of miR410 high expression in DCs stimulated by prostate cancer antigens and its related functions. (3) The molecular mechanism of suppression of miR410 high expression during DCs' immune responses to tumors by miR410* secreted by prostate cancer cells. With experiments on cellular level and gene knockout mouse model of prostate cancer, we intend to elucidate the role of miRNA in regulating immune cells and explore its clinical application, which might provide new gene targets and intervention strategies for the diagnosis and treatment of prostate cancer.

大量特异的microRNA(miRNA)参与了前列腺癌的发生发展，前列腺癌患者外周血含有特定的miRNA表达谱。但相关循环miRNA的作用不明。我们前期研究发现，前列腺癌患者外周血和前列腺癌细胞培养上清中含有大量的miR410*，而树突状细胞（DC）受到前列腺癌细胞碎片（抗原）刺激时则高表达其互补链miR410，而这一过程可以通过前列腺癌细胞培养上清孵育或者转染miR410* mimics 所抑制。本研究拟以循环miR410*为切入点，开展三方面的研究：⑴ 前列腺癌细胞表达分泌miR410*的分子机制；⑵ DC受前列腺癌抗原刺激后表达分泌miR410机制和相关的作用；（3）前列腺癌细胞分泌的miR410*抑制DC肿瘤免疫时分泌miR410的分子机制。在细胞和前列腺癌小鼠模型在体水平上阐明循环miRNA对机体免疫细胞的调控作用，并分析其临床意义，为前列腺癌的诊断和治疗提供新的靶点和干预策略。

现在大量的研究发现，肿瘤病人外周血中含有特定的肿瘤细胞释放的miRNA. miRNA 在肿瘤发生发展转移和免疫逃逸中发挥中重要作用。我们研究发现前列腺癌细胞释放大量的 miR-410-5p 进入外周血循环。研究发现，前列腺癌病人外周血中循环miRNA-410-5p (miR-410-5p)水平显著高于健康人和非前列腺癌疾病患者。ROC 曲线发现，血浆 miR-410-5p 前列腺癌诊断效能为 0.8097 (P < 0.001)，因此血清miR-410-5p 水平可能用于前列腺癌诊断的候选分子。我们进一步研究发现，循环miR-410-5p在AGO2携带下最终进入树突状细胞(DCs). 我们同时发现，肿瘤细胞抗原可以刺激DC合成分泌miR-410-5p来自于同一个前体pre-miR-410, 二者序列高度互补。miR-410-5p 进入DC后通过碱基配对与 miR-410-3p结合后二者降解，从而抑制肿瘤血管生成和肿瘤生长。我们的工作发现了一种新的由miRNA介导的免疫细胞与肿瘤细胞相互调控的关系。同时提供了一种可能的通过调控miR-410-3p 或者 miR-410-5p治疗肿瘤的新方法。我们的研究提出了一种DC的新功能，即非免疫功能。当遇到肿瘤抗原刺激的时候，DC可以合成释放miR-410-3p 减少肿瘤血管生成的方式抑制肿瘤生成。在这种意义上，我们的工作打开了免疫细胞和肿瘤细胞相互调控的新局面，为设计肿瘤治疗新策略奠定了基础。