TCP-2肿瘤靶向肽在结肠癌组织上特异性靶标的分离鉴定及靶向传输免疫治疗药物的研究

Identifying new targets and developing novel delivery agents for anti-tumor drugs are hot topics for targeted therapies for cancers. Recently, using phage display biopanning technology, we identified a small peptide named TCP-2 (a nine amino acid peptide). This peptide has been demonstrated to home selectively to tumor blood vessels rather than in normal organs. In addition, such peptide also specifically targets to M1 TAM (CD68+CD80+), rather than M2 TAM (CD68+CD163+) in both human and mouse colorectal cancer (CRC) tissues. These findings clearly indicate that there is a targeting site for TCP-2 on CRC. In this proposal, we shall isolate and identify the TCP-2-targeting molecule in CRC using a pull-down assay. We shall then characterize the expression of this specific molecule in both human and mouse CRC tissues using IHC and Western blot assays. This molecule could be used as a biomarker for the diagnosis and targeted site for chemotherapy. Furthermore, we shall also develop new therapeutic agents based on the unique properties of TCP-2 and TNFα/IFNγ, targeting both tumor blood vessels and M1 TAM. It can serve as a drug carrier and provides a powerful and selective cocktail immunotherapy for CRC. Characterisation of the binding molecules for TCP-2 and study of its delivery ability of anti-tumor drugs in CRC will provide solid evidences for early diagnosis and targeted therapies for CRC.

寻找新的药物作用靶点及开发新的靶向传输载体是癌症靶向治疗研究的热点。前期研究中，我们利用噬菌体展示实验，分离鉴定了一个靶向结肠癌组织的小分子多肽并命名为TCP-2。TCP-2特异性靶向肿瘤血管及抗肿瘤生长的M1型TAM，而对正常组织及促肿瘤生长的M2型TAM无明显结合。这些研究结果显示肿瘤组织中存在TCP-2多肽特异结合的靶点。本项目拟：运用蛋白质交互作用沉淀试验分离鉴定TCP-2多肽特异性结合靶点；采用人结直肠癌组织为对象，研究 TCP-2多肽的靶标蛋白的表达及其作为药物作用靶点的基础研究；运用基因重组技术制备TCP-2多肽与TNFα和IFNγ的融合蛋白，研究其靶向传输抗肿瘤药物免疫治疗结直肠癌的潜在价值。TCP-2多肽作用靶标的揭示及其靶向传输抗肿瘤药物的作用与机制研究，将会为结直肠癌的早期诊断和靶向治疗提供理论和物质基础。

寻找癌症靶向分子及开发新的靶向传输载体是癌症早期诊断和靶向治疗研究的关键步骤和研究热点。本课题以肿瘤靶向肽TCP-2多肽的应用为切入点，通过构建小鼠原位结肠癌模型、小鼠原位胰腺癌模型、小鼠动脉粥样硬化模型，结合在体和体外实验及临床标本相结合，明确了TCP-2多肽可特异性及选择性靶向结肠癌、胰腺癌组织肿瘤血管和M1型肿瘤相关巨噬细胞，及靶向动脉硬化组织中M1型炎性巨噬细胞；利用基因重组技术，结合小鼠原位结肠癌模型，初步明确了TCP-2多肽靶向传输生物制剂增强治疗结肠癌的作用，本研究主要发现点包括：1）TCP-2多肽靶向小鼠和人结直肠癌和小鼠胰腺癌组织肿瘤血管和浸润的M1型巨噬细胞；2）TCP-2多肽靶向小鼠动脉粥样硬化组织中浸润的M1巨噬细胞；3）TCP-2多肽靶向传输TNF-α、IFN-γ，增强其治疗结肠癌作用。这些研究结果显示TCP-2多肽具备靶向结肠癌、胰腺癌和动脉粥样硬化组织中M1巨噬细胞的特性；该多肽同时具备靶向传输生物制剂并增强其抗肿瘤活性的特点；TCP-2多肽及其相关生物制剂可能用于消化系统癌症包括结直肠癌和胰腺癌及慢性炎症性疾病的早期靶向诊断制剂和靶向用药载体。