Direct labeling of angiostatin with 99Tcm and its distribution in tumor bearing mice

    ZHANG Jinª²He, XU Haiª²Feng, SHAO Qiuª²Ju, ZHOU Feiª²Hua, ZHOU Runª²Suo, YUAN Mengª²Hui, GUO Wanª²Hong

    Department of Nuclear Medicine, Tangdu Hospital, Fourth Militray Medical University, Xi¡¯an 710038, China

    ¡¾Abstract¡¿ AIM: To observe the distribution of direct labelled angiostatin (AS) by 99Tcm in tumor bearing mice and to evaluate the value of 99Tcmª²AS in positive imaging of tumor. METHODS: Angiostatin was labeled by stannous reduced approach and the labeling efficiency was examined by TLC. The bioactivity of 99Tcmª²AS was observed using human umbilical vein epithelial cell line (CEV304). Blocking experiment was conducted to make sure that the combination of tumor and 99Tcmª²AS was related to angiostatin receptors. The EMT6 tumor bearing BALB/c mice were pretreated with nonª²labeled angiostatin 2 h before administration of 99Tcmª²AS. 99Tcmª²AS was injected via tail vein, the distribution of 99Tcmª²AS in vivo was observed and imaging was made. RESULTS: The labeling efficiency (>95%) of 99Tcmª²AS was high and its bioactivity was the same as that of nonª²labeled AS. Its distribution in tumor bearing mice indicated that the uptake of 99Tcmª²AS increased gradually 2-12 h after 99Tcmª²AS injection and the positive image of tumor was displayed clearly. The blocking with nonª²labeled AS decreased the uptake of 99Tcmª²AS. CONCLUSION: 99Tcmª²AS can gather in tumors in mice and this specific binding may be related to the receptors of AS. 99Tcmª²AS probably can be used in predicting the effects of antiª²angiogenesis therapy in tumor treatment. ......