[Application of 99Tc(m)-annexinV in predicting the therapeutic effect of chemical agent on lung cancer].
OBJECTIVE
To prepare 99Tcm-annexinV and evaluate its application in the early prediction of therapeutic effect of chemical agent on lung cancer.


METHODS
Annexin V was obtained by recombinant pichia pastoris expression, ammonium sulfate precipitation, and size-exclusion chromatography. The purified protein was labeled with 99Tc(m) at the N-terminal site by stannous chloride reduction and purified by desalting. The labeling yield and radiochemical purity of 99Tc(m)-annexinV were determined by instant thin-layer chromatography. The biological activity of 99Tc(m)-annexinV was tested by phosphatidylserine-exposed erythrocytes bound radioactivity counting. The lung cancer mice models were established by inoculating LA795 cells to right flank of 615 mice subcutaneously and tumor tissue transplantation. The biodistribution of 99Tc(m)-annexinV in lung cancer mice models were investigated at 6, 12, 24, and 48 h after cyclophosphamide administration.


RESULTS
The annexin V was secreted from pichia pastoris and purified by ammonium sulfate precipitation and size-exclusion chromatography with high yield. The annexin V could be labeled at room temperature with 50.2% radioactivity yield. The radiochemical purity of 99Tc(m)-annexinV reached up to 93.9% with intact biological activity. The biodistribution analysis demonstrated that 99Tc(m)-annexinV was excreted from kidney. The uptake of 99Tc(m)-annexinV at tumor reached maximum 48 h after cyclophosphamide administration while tumor to muscle ratio was 6.34 and tumor to blood ratio was 4.09.


CONCLUSIONS
99Tc(m)-annexinV derived from pichia pastoris was successfully prepared. It is useful in predicting the therapeutic effect of chemical agent on lung cancer.
Cai
Jiong
J
Department of Nuclear Medicine, PUMC Hospital, CAMS and PUMC, Beijing 100730, China. jiongcai@sina.com
Yu
Fei
F
Li
Fang
F
Wang
Shi-Zhen
SZ
D000818:Animals; D017304:Annexin A5 / Q000008:administration & dosage* / Q000493:pharmacokinetics; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D051379:Mice; D015609:Organotechnetium Compounds / Q000008:administration & dosage* / Q000493:pharmacokinetics; D014018:Tissue Distribution
D017304:Annexin A5; D015609:Organotechnetium Compounds; C417036:technetium Tc 99m annexin V