探讨乳腺癌特异性多肽PI携带外源性生物大分子靶向抗肿瘤的作用.将分离纯化获得的融合蛋白PI-EGFP与靶细胞MDA-MB-231体外共培养,探讨融合蛋白与靶细胞的结合能力;将此融合蛋白经尾静脉及肿瘤局部注射入荷瘤裸鼠体内,探讨其在肿瘤部位的聚集程度;利用分子克隆技术构建重组原核表达载体pET-28a(+)-pI-tk,诱导表达、分离纯化、鉴定获得的融合蛋白PI-HSV-TK,将不同浓度的融合蛋白与MDA-MB-231细胞共培养,经更昔洛韦(ganciclovir,GCV)作用后,探讨PI-HSV-tk对细胞的靶向杀伤效应.荧光显微镜下观察,在靶细胞内可检测到绿色荧光信号,经尾静脉及局部注射融合蛋白PI-EGFP后,在不同组织器官可见不同强度的荧光信号,在尾静脉注射组的肾脏和肿瘤部位可检测到荧光信号,而局部注射组仅在肿瘤部位可检测到;成功构建了重组原核表达载体pET-28a(+)-pI-tk;分离纯化获得高效表达的PI-TK融合蛋白,SDS-PAGE电泳及Western blotting鉴定融合蛋白的表达正确;CCK-8法及流式细胞仪检测显示,GCV对转导融合蛋白的MDA-MB-231细胞有杀伤作用,IC50值为152.64μg/mL.乳腺癌特异性转导多肽能携带生物大分子进入靶细胞,并携带具有杀伤效应的物质,使其发挥靶向治疗作用,为进一步探讨该多肽作为靶向性载体奠定实验基础和理论依据. To explore the effect of breast cancer-specific polypeptide PI on targeting antitumor activity of exogenous biological macromolecules.Methods: The fusion protein PI-EGFP isolated and purified was co-cultured with target cell MDA-MB-231 in vitro to explore the relationship between fusion protein and target cell The fusion protein was injected locally into the tumor-bearing nude mice via the tail vein and tumor to investigate the degree of aggregation of the fusion protein in the tumor site. The recombinant prokaryotic expression vector pET-28a (+) - pI-tk was induced by molecular cloning The fusion protein PI-HSV-TK was isolated, purified and identified. The fusion protein of different concentrations was co-cultured with MDA-MB-231 cells. After ganciclovir (GCV) tk targeted killing effect of cells.Under fluorescence microscope, green fluorescence signal can be detected in the target cells, through the tail vein and local injection of the fusion protein PI-EGFP, in different tissues and organs can see different intensity of fluorescence signal in The fluorescence signal was detected in the kidney and tumor site of the tail vein injection group, while the local injection group was only detectable in the tumor site. The recombinant prokaryotic expression vector pET-28a (+) - pI-tk was successfully constructed and was highly expressed Of PI-T K fusion protein, SDS-PAGE electrophoresis and Western blotting. The results of CCK-8 assay and flow cytometry showed that GCV could kill the MDA-MB-231 cells transduced with the fusion protein with IC50 of 152.64μg / mL. Breast cancer-specific transduction polypeptide can carry biological macromolecules into target cells and carry the killing effect of the substance, so that it can play a role in targeted therapy, to lay a foundation for further exploration of the polypeptide as a targeting vector And theoretical basis.