免疫促凋亡分子用于治疗HBsAg阳性肝细胞癌的研究

项目名称： 免疫促凋亡分子用于治疗HBsAg阳性肝细胞癌的研究

项目编号： No.81201777

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 肿瘤学1

项目作者： 阎博

作者单位： 中国人民解放军第四军医大学

项目金额： 23万元

中文摘要： 肝细胞癌（HCC）是最常见的恶性肿瘤之一，手术治疗复发率高，传统放、化疗对正常组织毒害大。本课题组曾将抗HER2单链抗体与促凋亡分子融合表达，构建的免疫促凋亡分子在HER2阳性肿瘤模型中证实具有明确的抗肿瘤作用。通过筛选改造，本课题组获得一株对HBsAg具有亲和活性并可经由内吞体进入HBsAg阳性肿瘤细胞的单链抗体（scFv15），为构建靶向HBsAg的免疫促凋亡分子奠定了基础。本课题拟将scFv15作为靶向识别结构域、促凋亡分子tBid作为杀伤效应结构域，构建靶向HBsAg的免疫促凋亡分子，并加入HA2序列作为转位结构域，以提高免疫促凋亡分子释放效率，增强对靶细胞的杀伤效果。通过细胞水平和动物水平实验，检测免疫促凋亡分子对HBsAg的亲和活性、内吞体破坏活性，及对HBsAg阳性HCC肿瘤的靶向性和杀伤活性。本课题具有扩展免疫促凋亡策略的理论意义，并对HBV相关HCC的治疗具有实际意义。

中文关键词： 免疫促凋亡分子；肝细胞癌；HBsAg；转位结构域；HA2

英文摘要： Hepatocellular carcinoma (HCC) is one of the most common malignant tumors occurring worldwide. High recurrence rates of surgical treatment and non-specific side-effects of radiotherapy and chemotherapy on normal tissues lead to limited clinical benefits of HCC therapy. Targeted therapy is needed for patients with HCC. We have established a novel antitumor strategy by generating a series of immunoproapoptotic molecules (IPMs) and confirmed its antitumor activity against HER2-positive tumors in vitro and in vivo. The hepatitis B virus surface antigen (HBsAg) is overexpressed in HBV-related HCC. We previously reported that scFv15, a human single-chain antibody, specifically recognized and entered HBsAg-positive HCC cells. Here, we switched our well-established immunoproapoptotic strategy from HER2-targeting to HBsAg-targeting and explored its killing capacity after introducing an endosomolytic HA2 motif. scFv15 was conjugated to a truncated form of the proapoptotic protein Bid (tBid) via the furin-cleavable motif from diphtheria toxin (Fdt) and the HA2 peptide of influenza hemagglutinin to generate the HBsAg-directed immunoproapoptotic molecule. The purified immunoproapoptotic molecules were tested for HBsAg-binding activity, endosome escape activity, and tumor cell killing efficacy using cultured HCC cells. In viv

英文关键词： immunoproapoptotic molecule；hepatocellular carcinoma；HBsAg；translocation domain；HA2