肿瘤淋巴转移监测用三重靶向近红外荧光造影研究

According to the literature, the lymphatic system throughout the body provides the main channels for tumor metastasis. It is noted that lymph node is one of the most common transfer route for early stage tumor metastasis, and the cure rate can reach as high as 80-90% for early-stage cancer. Whether there is a tumor metastasis on the lymph node can be utilized as important indicator during tumor staging, treatment and prognosis of clinical judgment. In recent years, near-infrared (NIR) fluorescence imaging of tumor and lymph node metastasis has been employed for early detection and diagnosis, and has developed into a research focus of oncology and surgery. Being the only clinical employed NIR imaging agent approved by FDA (Food and Drug Administration), Indocyanine Green (ICG) is lack of targeting group on tumor metastasis, and all the lymphatic system is imaged, tumor metastasis is deduced based on anomaly lymphatic structure. Furthermre, its half-life in the body is around 2-4 minutes, and the body remaining time is too short to meet the clinical need. To solve these problems, in the proposal, the main chromophore structure of ICG was retained to keep its basic property, a cancer targeted group folic acid and a mitochondria localization group triphenylphosphine were introduced into the structure to get ICG derivatives. And then it was further packaged into liposome bearing the folic acid label. After injection,the folic acid labeled liposome can target the lymphatic system first, and then target tumor cells; meanwhile,the ICG derivative can target tumor cells and locate in the mitochondria of tumor cell organelles after released by the liposome. Finally, the lymphatic tumour cells can be triple targeted with high selectivity and NIR fluorescence image can be acquired. After both in vitro and in vivo measurements, its potential clinical application will be further studied. All these can lay a foundation for detecting tumor metastasis through lymphatic node, early-stage cancer diagnosis and "fluorescent surgery".

遍布全身的淋巴系统是肿瘤转移的主要通道。淋巴结肿瘤转移是最常见的早期转移方式，也是临床上肿瘤分期、治疗、预后判断的重要指标。早期癌症治愈率可达80-90%，对肿瘤及其淋巴转移进行早期检测和诊断，是当今肿瘤学和外科学研究热点。吲哚菁绿(ICG)是美国FDA批准的唯一临床用荧光造影剂，对肿瘤转移灶负显影，没有靶向性，半衰期2至4分钟，注入后迅速被机体排出。本申请拟保留ICG发色团骨架，将其与癌细胞靶向基团叶酸连接，再与线粒体定位基团三苯基膦连接，合成靶向肿瘤细胞且定位其线粒体亚细胞器的ICG造影剂衍生物；再将其包裹到带有叶酸标签的脂质体中，借助脂质体对淋巴系统的靶向性，实现对淋巴结肿瘤转移灶的三重靶向近红外荧光造影。利用细胞、小动物活体荧光成像验证上述设想，获得具有自主知识产权的造影剂及其脂质体，实现对淋巴结肿瘤的选择性正染、成像，为监测肿瘤经淋巴转移、癌症的早期诊断及"荧光手术"创造条件。

早期癌症治愈率可达 80-90%， 对肿瘤及其淋巴转移进行早期检测和诊断，是当今肿瘤学和外科学研究热点。目前只有未发生转移的肿瘤可采取手术切除治疗，晚期恶性肿瘤手术困难且术后若干年仍会复发或转移，但是恶性肿瘤早期常无任何症状，需要开发合适的检测手段。化学药物疗法是肿瘤治疗中的重要手段之一，然而目前的化疗给药存在靶向性差、病灶部位有效药物浓度低、治疗效果不佳、毒副作用大等缺点，易破坏人体免疫力。为解决上述问题，我们开发了能够对癌细胞、正常细胞的溶酶体进行很好定位，实时监控细胞溶酶体pH变化的荧光探针，可以区分正常细胞和癌细胞，并利用肿瘤组织特殊的酸性环境对卵巢癌肿瘤进行荧光成像，为癌症的检测和治疗提供重要的信息。为解决化疗过程中肿瘤细胞摄入药物效率较低，对正常细胞及组织机能造成伤害等关键科学问题，我们提出了系统靶向药剂学概念，开发肿瘤靶向、多控智能释放、精准定位、纳米安全给药系统。该给药系统进入肌体后，其表面的叶酸等靶向基团将使其靶向癌细胞/组织，特别是，只有在癌细胞/组织中独特的酸性环境和谷胱甘肽（GSH）富集条件等多重参数共同作用下，才能使纳米材料溶解，智能释放担载的药物，从而实现对癌细胞/组织的靶向、精准定位、安全给药。即使有少量纳米载体进入正常细胞/组织，由于缺乏必要的智能药物释放条件，亦无法释放药物，可望从根本上避免化疗对正常细胞/组织的伤害。