拟设计在体内低毒、 靶向肿瘤细胞的抗癌多肽(记: GPG), 克服在抗癌治疗中使用化学类药物存在的缺点, 探讨用荧光光谱评价靶向肽对肿瘤肿块包覆状况的方法; 进行仅用一组基于双报告基团的小鼠模型(用EGFP转染的鼠肝肿瘤细胞H₂₂, 记: H₂₂-EGFP与荧光染料Cy7标记的GPG, 记: Cy7-GPG, 作报告基团), 就能完成抗癌肽体内主要性能监测的研究。 用H₂₂-EGFP构建小鼠移植瘤模型, 尾静脉注射Cy7-GPG后, 用成像仪(Ex=750 nm)观察到肿瘤的荧光光子数不断增大, 从第4 h的(3.90±0.260)×10⁶ photons·(s·cm²)^-1(单位下同)升至第24 h的(1.28±0.330)×10⁸, 橙色荧光全部聚集到肿瘤上, 而对照组中Cy7的荧光没有聚集在肿瘤上, 且肿瘤上光子数也无明显变化; 此时, 用成像仪在实验组同一只鼠上, 分别用750和488 nm激发波长录得包覆状物和实际肿瘤肿块的图片, 表明它们的大小和形状一致; 以上两项测定后, 再每2 d一次往上述实验组鼠体内注射GPG, 在成像仪上(Ex=488 nm)监测到它们的肿瘤变小, 荧光光子数逐渐降低, 从第2 d的(4.15±0.291)×10⁶降至第56 d的(4.75±0.283)×10⁴, 空白对照组正相反。 GPG与化学药物环磷酰胺抗癌活性相当, 但后者对小鼠毒副作用严重; 最后, 往上述GPG药效实验组鼠体内注射Cy7-GPG, 48 h后处死小鼠, 取出内脏器官及肿瘤肿块, 在成像仪上(Ex=750 nm)录得它们的荧光光子数。 实验表明GPG靶向性强、 对肿瘤肿块包覆程度高、 药效强, 对其他主要脏器无毒副作用。 本文构建的基于双报告基团荧光成像模型, 可监测靶标被包覆状况, 克服了传统只能对靶向肽靶向功能进行评价的弊端, 增进对药物作用机理的认识; 本文仅消耗一组实验鼠模型, 节约实验成本、 简捷地监测了靶向肽主要性能, 表明GPG在体内性能较好, 具有应用价值。

This paper explores the in vivo action of an anti-cancer polypeptide (denoted by: GPG) with low toxicity that targets tumor cells. This aims to overcome the limitations of current anti-cancer therapy, and explores tumor evaluation and mass coverage status with the targeting peptide, by the use of spectrofluorimetry. The study focuses on monitoring the main actions of the anti-cancer peptide in vivo, with only one set of mouse models based on dual reporter dyes (H₂₂ hepatocarcinoma cell transfected with EGFP, denoted by H₂₂-EGFP, and GPG labeled with fluorescent dye Cy7, denoted by Cy7-GPG, were used thereof). A transplanted tumor mouse model was constructed with H₂₂-EGFP and Cy7-GPG was injected in the tail vein. The imager(Ex = 750 nm) revealed that the number of fluorescent photons in the tumor increased continuously from (3.90±0.260)×10⁶ photons·(s·cm²)^-1 at the 4th hour (the same unit below) to (1.28±0.330)×10⁸ at the 24th hour. Orange fluorescence accumulated on the tumor completely, with no fluorescence accumulation on the tumor in the Cy7 control group. There was no significant change of fluorescent photon number on the tumor as well. At this time, images of the coating Cy7-GPG and actual tumor mass in the same experiment mouse were recorded, at 750 and 488 nm excitation wavelength respectively, indicating that they were of the same size and shape. Subsequently, GPG was injected into the mice in each of the experimental groups every 2 days. The imager(Ex = 488 nm) revealed the tumor had become smaller, while the number of fluorescent photons gradually decreased from (4.15±0.291)×10⁶ on the 2nd day to (4.75±0.283)×10⁴ on the 56th day. However, the condition of the blank control group was just the opposite. The anti-cancer activity of GPG was comparable to cyclophosphamide. However, the latter had more serious toxic side effects on mice. Finally, mice in the GPG efficacy experiment group were injected with Cy7-GPG and were then sacrificed 48 hours later, with the internal organs and tumor masses extracted for recording the number of fluorescent photons using the imager(Ex=750 nm). The experiment showed that GPG had precise targeting, wider coverage, and strong efficacy, with no toxic or side effects on other organs. The fluorescence imaging model constructed using dual reporter dyes used in this paper was utilized to monitor the coverage of targets; it overcame the limitations of the traditional evaluation method for targeting the function of peptide and improved the understanding of the mechanism of drug action. Only one set of mouse models was used in this experiment. Hence the main performance of the targeting peptide was monitored in a simple and cost-effective manner, indicating that GPG has excellent performance and useful application in vivo.