pH敏感生物靶向复合纳米颗粒增强鼻咽癌放射敏感性及其机制研究

Nasopharyngeal carcinoma (NPC) is a remarkably type of head and neck cancer, which is prevalent in southern China. Radiotherapy is the major treatment for nasopharyngeal carcinoma. However, irradiation for nasopharyngeal carcinoma has a high treatment failure rate because of its rapid growth and invasive behavior.We found arsenic improve radiosensitivity by combine with irradiation in our previously work. In this study, we designed a novel multi-functional arsenic nanoparticle，which based on the traditional Chinese herbal medicines. Using pH-sensitive liposomes encapsulated and could be release-control (acidic pH environment in tumor internal), modified nanoscale arsenic(As2O3/LPs)，coupling with humanized monoclonal antibody of EGFR -Nimotuzumab. Whereby, As2O3/LPs@NitzAb retained the anti-tumor effection of As2O3 and being a radiosensitizer, but also Nimotuzumab retained the characteristics of specific targeting. Not only Nimotuzumab is anti-tumor but also is a radiosensitizer.By contrasting the irradiation-resisit cell lines of NPC(CNE2R), we investigate the mechanism of anti-tumor and radiaosensitivity in vitro and in vivo.These studies will be actually instrumental valuable for clinic application in the future.

鼻咽癌是华南地区的一种常见恶性肿瘤。放射治疗是鼻咽癌最主要治疗手段。肿瘤残余及肿瘤放疗抗拒是鼻咽癌治疗失败的主要原因。我们前期发现传统中药材砒霜（AS2O3，砷剂）可以提高肿瘤放疗敏感性。 本研究拟以砒霜纳米化为基础，利用pH敏感脂质体包裹修饰纳米级砒霜，再将其外部偶联人源化EGFR单克隆抗体（泰欣生），形成复合物-As2O3/LPs@NitzAb。此复合物不仅保留了砒霜的抗肿瘤和潜在的放射增敏效应，又可通过泰欣生的单抗生物学特性，特异靶向作用于EGFR高表达的鼻咽癌细胞，进一步利用泰欣生本身具有抗肿瘤及放射增敏效应，从而将其功效进一步放大。通过构建射线抗拒型鼻咽癌细胞株（CNE2R）及其荷瘤鼠模型，从体内、外水平探讨As2O3/LPs@NitzAb抗肿瘤、放疗增敏效应及其逆转射线抗拒的分子机制，为后续临床应用提供实验研究基础。

本研究通过制备新型复合纳米颗粒As2O3/LPs@NitzAb、As2O3/LPs及As2O3 @NitzAb，采用分子生物学、流式细胞仪、免疫荧光化学、克隆形成实验、电镜等手段在细胞水平研究上述各种纳米颗粒联合X-ray线后对于鼻咽癌细胞株的作用，首次发现：1）成功制备多功能复合纳米颗粒As2O3/LPs@NitzAb并对其进行表征，上述材料纳米在体外稳定性良好；偶联NitzAb的复合纳米颗粒As2O3/LPs@NitzAb抗体活性保存良好；2）体外实验证明该复合纳米颗粒粒对鼻咽癌肿瘤细胞有抑制作用并对其有明显促凋亡作用；3）As2O3/LPs@NitzAb可能为通过增加G2/M期阻滞、阻止DNA断裂修复其作用、启动介导的MAPK凋亡通路及ROS产生增多激活MAPK途径抑制鼻咽癌细胞株生长，促进肿瘤细胞凋亡并增加对放射线敏感性；4）As2O3/LPs@NitzAb联合X-ray射线可增加鼻咽癌细胞双链DNA断裂、胞内ROS产生，上调辐射后DNA修复蛋白Ku70、Ku80、Rad51等蛋白表达；5）上述纳米颗粒联合X-ray时体外干预鼻咽癌肿瘤细胞时增敏效应明显；As2O3/LPs@NitzAb有望发展成为具有精确靶标功能的调强放疗增敏剂及靶向抗肿瘤制剂。