具有体内DC特性的FGFR1适配体生物反应器靶向抗肿瘤研究

The C-type lectin domain family protein 9A (Clec9A) exists in the specific surface of dendritic cells (DC) and is the best known target to improve the immune response; MIP3α, the most important specific chemokine, can effectively improve the antigens presenting ability of DC. We propose here to use SELEX technology to screen out an aptamer that can specifically bind to the FGFR1, a non-immunogenic, neovasculature marker of tumors. The screened out aptamer will then be encapsulated using nano liposome, along with virus recombinant that can efficiently co-express MIP3α, and Clec9A genes and produce a final complex product: "FGFR1 aptamer-MIP3α/Clec9A bioreactor". This bioreactor will generate high concentrated MIP3α and Clec9A at the targeted tumor site, and FGFR1 aptamer can also inhibit angiogenesis in tumor. This bioreacctor will greatly enhance specifically targeted killing effect on tumor cells and / or tumor angiogenesis. Accordingly, such "FGFR1 aptamers-MIP3α/Clec9A bioreacctor" is very likely a promising in vivo DC vaccine. We will investigate the mechanism by in vivo and in vitro approach to explore a new strategy of tumor biotherapy.

C型凝集素结构域家族成员9A（Clec9A）蛋白存在于特定DC表面，是目前已知的改善免疫应答的最好靶标；MIP3α是DC最重要的特异性趋化因子， 能有效提高DC递呈抗原能力。结合前期工作基础，本课题拟运用SELEX技术筛选出能与肿瘤新生血管标志分子FGFR1特异结合且无免疫原性的适配体后，将其与转染高效共表达MIP3α和Clec9A基因的病毒重组子用纳米脂质体包裹偶联成一种"FGFR1适配体-MIP3α/Clec9A生物反应器"，该反应器能让肿瘤部位靶向获得高浓度MIP3α和Clec9A，加上FGFR1适配体本身具有一定的抗肿瘤血管生成作用，这将极大增强它们对肿瘤细胞和/或肿瘤新生血管特异性靶向杀伤作用。因此，这种"FGFR1适配体/Clec9A生物反应器"极有可能是一种简单而有效的体内DC疫苗模式。我们将通过体内外实验观察其抗肿瘤作用并探讨其作用机理，寻找一种肿瘤生物治疗的新策略。

本项目利用基因工程技术成功制备了FGFR1适配体-MIP3α/Clec9A 生物反应器（aFR1/MIP3α-Clec9A）并在体内进行抗肿瘤作用和毒副作用观察。研究发现，aFR1/MIP3α-Clec9A复方生物反应器具有肿瘤新生血管靶向性和抑制肿瘤血管生成作用；具有较好体内DC趋化募集作用；还发现该生物反应器具有一定溶瘤作用且安全性较好。同时增加了FGFR1/MIP3α-Fc融合蛋白制备及其用途研究，亦发现其具有良好的DC趋化作用。阶段性成果将为深入研究靶向FGFR1肿瘤生物治疗提供新的策略。