醛脱氢酶荧光探针的设计合成及其在肿瘤干细胞成像中的应用

The cancer incidence and mortality are increasing year by year in the worldwide. Metastasis and relapse are the main causes of cancer death. It is indicated that cancer stem cells (CSCs) are closely associated with cancer metastasis and relapse, while aldehyde dehydrogenase (ALDH) is an important marker of CSCs. The reported fluorescent probes are all based on the substrate structure, which cannot be used to image ALDH in vivo due to their lower sensitivity and selectivity. A novel series of probes based on the inhibitor structure are planned to design and synthesize, which will be installed with small molecular inhibitor and optimal fluorophore, and these two functional groups will be conjugated by a long flexible chain. The new probes targeting ALDH will be applied in isolation and identification of ALDH-positive CSCs in MDA-MB-231 and H460 cancer cell lines, and further in fluorescence imaging and tracking of CSCs in vivo. This project will provide a new analytical method and technique for the isolation, identification and tracking of CSCs in vitro and in vivo, and will further promote the cancer therapy and the diagnosis of cancer metastasis and relapse.

癌症的发病率和死亡率逐年上升，转移和复发是导致癌症患者死亡的主要原因。研究表明，肿瘤干细胞与癌症的转移和复发密切相关，而醛脱氢酶是肿瘤干细胞的重要标志分子。目前报道的醛脱氢酶荧光探针均为底物型探针，灵敏度低，选择性差，无法实现活体成像。本项目拟设计合成基于抑制剂的荧光探针，即以醛脱氢酶的小分子抑制剂为识别基团，以常用荧光母核为荧光团，采用柔性长链将二者连接，构建靶向醛脱氢酶的新型荧光探针，从而对高表达醛脱氢酶的肿瘤干细胞进行荧光成像。以上述探针对MDA-MB-231和H460等细胞株中高表达醛脱氢酶的肿瘤干细胞进行染色和分选，并进行活体成像和示踪，从而建立肿瘤干细胞的体内外成像新方法。研究结果不仅可以高效实现对肿瘤干细胞的分离、鉴定、示踪，而且对于癌症的早期诊断、治疗以及癌症转移、复发的监测具有重要意义。

癌症的发病率和死亡率逐年升高，目前对于癌症的发生发展及转移等过程的分子机制尚不十分明确。已有研究表明，细胞癌变及肿瘤转移等与胞内的氧化还原状态密切相关。因此，针对肿瘤细胞及其干细胞内的氧化还原标志物，主要包括醛脱氢酶及其底物甲醛等，发展新的高效的原位荧光分析方法，对于癌症的诊断治疗及发病机制研究具有重要意义。鉴于此，本项目基于新的识别机制及特异性底物结构，结合近红外或双光子荧光报告基团，发展了一系列高选择、高灵敏、性能优良的荧光探针分子，可用于对细胞及活体内的醛脱氢酶等标志分子的分布及活性变化进行实时原位可视化成像，建立了体内外荧光成像分析新方法。上述探针及其成像方法有助于深入研究肿瘤细胞氧化还原平衡的化学生物学，可用于肿瘤细胞及其干细胞的染色和分选，并在多种肿瘤细胞及动物模型中得到应用。