以FGFR1为靶标的肽衍生物设计与抗肿瘤活性研究

FGFR1 is a important target for tumor treatment, but there are no FGFR1 inhibitors drugs in the clinical application. Compared with small molecule inhibitors targeting intramembrane kinase domain, the inhibitors targeting ligand binding domain of extra membrane exhibited better selectivity. In our previous work, heptapeptide P39 and P40, which have high level of specific binding to FGFR1 ligand binding domain, were identified from a phage display heptapeptide library. Even though the peptide inhibitors are unstable in vivo, they provided excellent lead for designing the peptide derivatives drugs which are stable in vivo. The preliminary experiment showed that the hot residue of P39 calculated by the free energy calculations was consistent with the result of alanine scanning. In this project P39 and P40 are chosen as the lead peptides. Molecular dynamics simulation, free energy calculation, and alanine scanning method are adopted to explore all the possible key binding residues on the leading peptides. Based on these key residues, the peptide derivatives library are designed and screened via the molecular docking technique. Subsequently promising peptide derivatives are synthesized, and then screened the binding force and binding specificity by SPR. The active peptide derivatives are used to study the stability, the antitumor effects and the mechanism in vitro and in vivo. It will be expected to design and screen FGFR1 antagonistic peptide derivatives with preferable stability, high selectivity, and excellent antitumor activity in vitro and in vivo, which can provide novel design strategy for the inhibitors binding to the extracellular ligand binding domain..

成纤维细胞生长因子受体1（FGFR1）是重要的肿瘤治疗靶点，但目前尚无FGFR1抑制剂药物上市。与膜内激酶域的小分子抑制剂相比，膜外配体结合域抑制剂具有更好的靶向选择性。我们在前期用噬菌体展示技术筛选到与FGFR1配体结合域有特异高亲和力的短肽P39和P40，虽然短肽抑制剂体内不稳定，但为设计体内稳定的肽衍生物药物提供了优秀的先导物。进一步预实验显示通过自由能计算出P39的热点残基与丙氨酸扫描结果吻合。本项目拟以P39和P40为先导肽，用自由能计算、动力学模拟和丙氨酸扫描法确定先导肽的结合热点残基，并在此基础上设计肽衍生物库，建立分子对接模型进行虚拟筛选；合成肽衍生物，用SPR进行结合力和结合特异性筛选，获得活性肽衍生物进行稳定性及体外和体内抗肿瘤药理药效研究。预期设计得到稳定性好、靶向选择性强、有良好体外和体内抗肿瘤活性的FGFR1拮抗肽衍生物，为膜外配体结合域抑制剂药物设计提供新策略。

成纤维细胞生长因子受体1（FGFR1）是重要的肿瘤治疗靶点，但目前尚无FGFR1抑制剂药物上市。与小分子抑制剂相比，肽类抑制剂具有相对较低的毒性和较好的靶向选择性。我们在前期用噬菌体展示技术筛选到与FGFR1配体结合域有特异高亲和力的短肽P39，但由于P39半衰期短限制了其成药性，但P39为设计体内稳定的肽衍生物药物提供了优秀的先导物。本项目通过动力学模拟自由能计算发现P39氮末端1、2和7号残基可能为与FGFR1结合的非热点残基；合成了P39氮末端的7个丙氨酸扫描肽，通过SPR等实验确证了其6和7号残基为可以修饰的非关键性氨基酸残基；综合丙氨酸扫描和自由能计算确定了7号残基为最有可能能够被改造的残基，进一步设计合成了7号残基被取代的七条肽衍生物，其中五条均能够剂量依赖性的与FGFR1结合，结合能力与P39相当。优选P73，发现其能剂量依赖性地阻滞FGF2诱导的胃癌细胞SGC-7901和BGC-823的细胞周期进程。体内给药（60mg/kg.day）20天后，能够明显抑制SGC-7901裸小鼠异位瘤的形成，其抗肿瘤效果明显优于先导肽P39,与阳性药物AZD4547（20mg/kg.day）的效果相当。体重-时间生长曲线显示，P39和P73可能具有比AZD4547相对较低的体内毒性。P73为具有较好研发前景的FGFR1拮抗肽衍生物。本项目也设计合成了三类新型FGFR1小分子激酶抑制剂，筛选到多个活性化合物。其中NDGA类活性抑制剂1B、D12和D15具有很好的体外抗胃癌活性。L16H50能基于靶向FGFR1，抑制其下游信号通路，起到良好的体外抑制胃癌细胞生长、诱导细胞凋亡的抗肿瘤效果，体内具有明显的抑制SGC-7901裸小鼠异位瘤形成的效果。通过本项目的实施，为FGFR1抑制剂药物的研究提供了新的内容和策略，为肿瘤治疗提供了新的候选药物。