131I-Herceptin在昆明小鼠及荷人卵巢癌裸鼠模型中的生物分布和显像

目的 研究131 I标记抗人表皮生长因子受体-2蛋白(HER-2/neu)单克隆抗体Herceptin在正常昆明小鼠和荷人卵巢癌裸鼠体内的生物分布及荷人卵巢癌裸鼠的放射免疫显像特点.方法 (1)Iodogen法131I标记Herceptin,测定其标记率、放化纯、稳定性及免疫活性.(2)流式细胞仪和免疫组织化学法分别检测人卵巢癌SKOV-3、HO-8910细胞株及瘤组织HER-2/neu表达情况.(3)计算131I-Herceptin经昆明小鼠尾静脉注射后5,15,30 min和1,2,4,12,24,48,72 h及荷瘤裸鼠尾静脉注射后4,12,24和48h的每克组织百分注射剂量率(%ID/g)和肿瘤/非肿瘤组织放射性(T/NT)比值.(4)行131I-Herceptin荷卵巢癌裸鼠模型显像,观察注射后1,2,4,8,12,24,48,72,96和120h显像情况并确定最佳显像时间.结果 (1)131I-Herceptin标记率为89.8%,放化纯为98.4%,24 h后仍大于80%,标记物免疫活性较好.(2)SKOV-3细胞株HER-2/neu高表达,表达率92.67%;而HO-8910细胞株表达很低,表达率仅9.59%.(3)131I-Herceptin在昆明小鼠体内主要经肝、脾及肾代谢,血液快相半排期为0.27 h,慢相半排期为51.96h.在荷人SKOV-3移植瘤部位,24 h时放射性摄取值达到18.08%ID/g,显著高于其他脏器组织;T/NT比值随时间延长逐渐增高,72 h时肿瘤/脑放射性比值高达27.27.(4)SKOV-3荷瘤裸鼠在尾静脉注射131I-Herceptin后2 h即可见移植瘤放射性浓聚,48 h后与周围组织对比更为明显,至120 h时仍见移植瘤部位放射性明显浓聚,与对侧感兴趣区比值高达11.44.而HO-8910荷瘤裸鼠各时间点移植瘤几乎未见放射性浓聚.结论 131I-Herceptin对荷人SKOV-3移植瘤具有良好的靶向作用,有望用于高表达HER-2/neu的人卵巢癌患者放射免疫显像及其复发转移灶的靶向治疗.

Biodistribution and radioimmunoimaging of 131 I-Herceptin in healthy KM mice and nude mouse models bearing human ovarian cancer xenografts

Objective To study the biodistribution of anti-HER-2/neu monoclonal antibody Herceptin labeled by 131I(131I-Herceptin) in healthy KM mice and nude mice bearing human ovarian cancer xenografts and radioimmunoimaging (RII) of the nude xenografts-bearing mice.Methods 131I-Herceptin was prepared using Iodogen method.The labeling efficiency, radiochemical purity, stability and immunocompetence were measured.The percentage activity of injection dose per gram of tissue (%ID/g) and the radioactivity ratio of tumor to non-tumor tissue (T/NT) were calculated for each time point.The optimal time for imaging was investigated by comparing the 131I-Herceptin SPECT for the nude mouse models bearing ovarian cancer xenografts at different time points.Results The labeling efficiency and radiochemical purity of 131I-Herceptin were 89.8% and 98.4%, respectively.The labeling was stable and had good immunocompetence.131 I-Herceptin was cleared rapidly mainly through liver, spleen and kidneys, consistent with first order two-compartment model.The uptake of 131I-Herceptin in the tumors bearing human SKOV-3 xenografts was much higher than that in nontumor tissue.The% ID/g was 18.08 in the tumor at 24 h post injection.The T/NT ratio increased with time and was 27.27 at 72 h post injection.The tumors in nude mice bearing SKOV-3 xenografts could be visualized on 131I-Herceptin SPECT imaging 2 h post injection; definitely identiffed 48 h post injection and the radioactivity ratio of tumor to contralateral tissue was 11.44 at 120 h post injection.However, the tumor in nude mice bearing HO-8910 xenografts did not show abnormal uptake of 131 I-Herceptin at each time point.Conclusions 131 I-Herceptin is a good radiopharmaceutical targeting SK-OV-3 xeuografts and it may be useful in imaging carcinoma of ovary and target therapy of its metastases with high HER-2/neu expression.