Biodistribution Study On MA-GM-CSF Liposome In Mice With Human Leukemia

Objective: To prepare MA-GM-CSF immunoliposomes and observe the cytotoxicity of HL-60 cells treated with the immunoliposomes;to prepare 131I-MA-GM-CSF immunoliposomes (131I was used as tracer agent) and observe its tissue distribution in SCID mice with human acute myelocytic leukemia (AML) for certifying its specificity of distribution and providing the preclinical data for AML therapy.Methods: 131I-MA liposomes were prepared by reverse-phase evaporation(REV),the encapsulation efficiency and the labeling rate of 131I were determined.GM-CSF was coupled to the 131I- MA liposomes by glutaraldhyde method , and its coupled efficiency was measured by UV-spectrophotometric analysis;The cytotoxicity of HL-60 cells were investigated by tetrazolium microculture(MTT) cellular cytotoxicity test. The xenograft model of human leukemia was established in SCID mice, verified by the analysis of FCM,chromosome and pathology. The mice developed leukemia was divided into tow groups,via tail vein,was treated with the mixture of 131I-MA liposomes and GM-CSF or 131I-MA-GM-CSF immunoliposomes respectively,and a groop of normal SCID mice was treated with 131I-MA-GM-CSF immunoliposomes. The biodistribution of 131I-MA-GM-CSF in the mice was studied.Results: 1,The encapsulation efficiency of MTZ and Ara-C was 80.1% and 84.2%,the labeling rate of 131I was 86.6%,and the coupled efficiency of GM-CSF was 54.0%. 2,MA-GM-CSF immunoliposomes,MA liposomes and MA all put up cytotoxicity of HL-60 cells,and the cytotoxicity increased in the dose-dependent manner. The cytotoxicity of MA-GM-CSF immunoliposomes was better than MA liposomes and MA(p<0.05),and the cytotoxicity of MA liposomes was better than MA(p<0.05). 3,The inoculated HL-60 cells could grow in vivo in SCID mice,which developed leukemia in 4~5 weeks(verified by the analysis of FCM,chromosome and pathology ) . 4,131I-MA-GM-CSF immunoliposomes were mainly concentrated in bone marrow and spleen of the mice developed leukemia. In these tow tissue,they were all uptaken to peak in 30 minutes after injection,the percentage of injected dose per gram(%ID/mg)was higher than the control and the normal (p<0.05),and maintained at a higher level in 24 hours than other tissues. Moreover,the biodistribution of 131I-MA-GM-CSF immunoliposomes in liver and lung was higher than other groops.And in kidney,the three groops had not difference.In the blood, the peak values of 131I-MA-GM-CSF immunoliposomes appeared in 5 minutes after injection,and it was lower than the control and the normal(p<0.05). Conclusions:1,The method of reverse-phase evaporation(REV)was equal to the preparation of MA-GM-CSF immunoliposomes , the encapsulation efficiency and the coupled efficiency were so satisfying. 2,In vitro,MA-GM-CSF immunoliposomes have cytotoxicity of HL-60 cells which has tagetability compared with MA liposomes. 3,The biodistribution of 131I-MA-GM-CSF immunoliposomes in SCID mice with leukemia has organ relative specificity. It is concentrated in bone marrow,spleen and tumor which made the medicine concentrate relative specifically into tumor and decrease damage to other organ when using for leukemia.