酸敏感修饰脂质体运载miR-155分子探针用于预测乳腺癌多药耐药性及其逆转效果的实验研究

Chemotherapeutic drug resistance is a significant reason for the recrudescence and the metastasis of breast cancer. miR-155 is an important miRNA closely related to the drug resistance of cancer chemotherapy. This project is trying to study the feasibility and effectiveness of investigating the multidrug resistance on breast cancer cells and the tumor bearing animals by antisense imaging with molecular probe of antisense peptide nucleic acids targeting miR-155. The antisense probe is delivered by pH-sensitive and PEG-modified liposome to improve the probe’s accumulation at the lesion. The vehicle liposome is modified by long-chain PEG to reduce the probe degradation by nuclease and the liposome phagocytosis by reticulo-endothelial system. The pH-sensitive hydrazine bond linking long-chain PEG and liposome is used to increase the probe accumulation at cancer lesion of slight acid microenvironment, and the Tat cell-penetrating peptide is used to enhance the probe penetration into cells. All of the design is to improve the microPET imaging efficacy. Our research is about to investigate the genes’ expression and regulation in cancer cells by antisense imaging, and offer effective strategies to predict cancer multidrug resistance and monitor the efficacy of drug resistance reversion treatment, which will provide evidence for cancer precise diagnosis and therapy decision.

化疗耐药是乳腺癌复发和转移的重要因素，miR-155是与肿瘤化疗耐药密切相关的miRNA。本项目拟构建酸敏感的修饰脂质体运载靶向miR-155的分子探针对乳腺癌耐药细胞及荷瘤动物模型进行核素显像研究，并用姜黄素逆转肿瘤耐药性后进行再次显像，以探索该分子影像探针对评估乳腺癌多药耐药及监测其耐药性逆转的可行性和有效性。本研究以miR-155为靶点设计反义探针，通过长链PEG修饰的脂质体运载探针以降低核酸酶对探针的降解和网状内皮系统对脂质体的吞噬，脂质体通过酸敏感的腙键与长链PEG连接以提高探针在肿瘤微酸环境下的聚集，并通过Tat细胞穿膜肽促进探针进入肿瘤细胞内，改善其PET显像效果。本研究将通过靶向miR-155的分子影像探索肿瘤细胞内基因的表达和调控，为预测肿瘤多药耐药和监测耐药逆转治疗策略提供有效手段，进而有望为肿瘤的精准诊疗提供依据。

三阴性乳腺癌(TNBC)具有高度侵袭性，恶性程度高，预后较差，治疗方法选择有限，严重威胁女性健康。本项目从不同分子角度去探索可能改善TNBC治疗和预后的新的成像方法。.本项目前期主要研究基因水平miR-155分子的在体可视化对于TNBC早期诊断和耐药监测的意义。随后从蛋白质水平研究人类母体胚胎亮氨酸拉链激酶(maternal embryonic leucine zipper kinase, MELK)的在体可视化为TNBC临床监测、靶向治疗和预后判断提供重要信息。.我们成功构建了特异性靶向miR-155的反义探针[99mTc]-HYNIC-ASON155和[99mTc]anti-PNA-155，探针标记率和放射化学纯度高，体、内外稳定性好。反义探针对miR-155于细胞水平和荷瘤鼠水平均表现出良好的靶向性。随后，我们通过标记MELK的特异性抑制剂OTSSP167成功构建了新型分子探针[11C]C-OTSSP167和[18F]F-ET-OTSSP167。该探针能够在体可视化MELK的表达，同时也能够反映OTSSP167在TNBC中的累积情况，从而为OTSSP167治疗TNBC提供理论依据。.TNBC由于缺乏有效的靶向治疗，且易出现耐药，治疗较为棘手，预后较差。本研究从基因和蛋白水平，无创可视化两种耐药相关分子miR-155和MELK在TNBC的表达情况，为TNBC的治疗和耐药监测提供重要依据。