适配体pRNA纳米嵌合胞外囊泡-致死siRNA选择性提高肿瘤对EGFR沉默敏感性的研究

Recently prostate cancer (PCa) incidence continues to rise in China, and PCa has been always the major disease of adult male reproductive health. Epidermal growth factor receptor (EGFR) has been considered as cancer theraputical target while it is not efficient for only silencing EGFR. The siILK screened from siRNAs library could significantly enhance lethal therapy with iEGFR, but without targeted delivery, these agents will also sensitize surrounding normal tissues. RNA interference is a promising new approach for targeting disease associated genes and pathways. The critical challenge for translating RNAi therapy is delivery, particularly for specific cell types. Previously, we developed prostate-targeted RNA interference agents which selectively sensitize PSMA-positive cells to IR via aptamer-siRNAs, delivered by PSMA aptamers, and selectively inhibited PCa cells and xenografts. Based on our previous research, here we screen ideal sensitizing lethal siRNA for silenced EGFR cancer cells through siRNA library and design nanoparticle aptamer-pRNA linked extracellular vesicles-siRNAs(Apt-pRNA-EVs-siRNAs) to selectively silence the target gene. By clarifying the lethal mechanism of apt-pRNA-EVs-siRNAs, in animal model, we will intravenous inject apt-pRNA-EVs-siRNAs for PCa target duel siRNA lethal therapy. We believe the siRNAs target duel lethal therapy has great potential application for future clinical translation.

近来我国的前列腺癌（PCa）发病率持续升高，已成为危害男性生殖健康的重大疾病。表皮生长因子受体(EGFR)被广泛认为是肿瘤治疗的潜在靶点，然而仅沉默EGFR对肿瘤细胞的致死效应不明显。我们筛选到的致死增敏siILK可极大增加EGFR沉默的致死效应，然而未经靶向递 送，也会导致周围的正常组织增敏。RNAi作为新的治疗方法已得到广泛认可，如何将siRNA靶向导入细胞是其所面临的挑战。申请人在以往工作中，设计PMSA aptamer-siRNA，靶向放射增敏，抑制前列腺肿瘤的生长。本项目通过siRNA文库筛选致死增敏siRNA；设计新型的含PSMA-apt 的pRNA纳米-胞外囊泡-siRNAs(Apt-pRNA-EVs-siRNAs)靶向输送致死及增敏siRNAs，研究并阐明双siRNAs致死前列腺癌细胞的作用机制;通过静脉给药，研究其靶向治疗的作用，为临床转化应用提供理论依据。

表皮生长因子受体(EGFR)被广泛认为是前列腺癌治疗的潜在靶点，然而仅沉默EGFR对肿瘤细胞的致死效应不明显。为了实现更好的治疗效果，我们开展了本项目研究。我们筛选到了EGFR沉默的致死增敏因子siILK，细胞水平验证了siILK对细胞生长的影响以及与siEGFR的合成致死作用，确认了其增敏作用；进一步我们在细胞和动物水平证明PSMA Apt-siEGFR和PSMA Apt-siILK能通过DICER途径显著抑制各自靶基因并部分抑制肿瘤细胞生长，并不会引起IFN免疫反应；靶向双致死研究表明两者结合能显著限制肿瘤的生长，PSMA Apt-siILK表现出了对PSMA Apt-siEGFR的致死增敏作用。项目结果为siRNAs用于肿瘤的治疗提供新思路，对利用核酸适体靶向运输siRNA治疗恶性前列腺癌以及利用该技术对其它肿瘤的靶向治疗有着重要的影响。