Study On The Synthesis Of16α-[¹⁸F]fluoro-17β-estrogen And Its Tracing Effect Of Breast Cancer Cells

Objective：1Reduce the synthesis cost of specific estrogen receptor imaging agent18F-Fluoroestradio (18F-FES), improve the quality control projects, meet the clinicalneeds of18F-FES dosage and safety.2Clear the tracing significance of18F-FES with the cells of different levels of estrogenreceptor expression, and discussed its mechanism.Methods:1Investigate influencing factors of synthesis of18F-FES used automatic synthesisdevice (Tracerlab FXFN) throught orthogonal experiment (L1645), with amount ofprecursor(mg), amount of nuclide(mci), times of acetonitrile used (time),hydrochloric acid concentration (mol/L), hydrolysis temperature (℃) as maintargets, set synthetic productivity as index, select the best synthesis conditions.2According to the best synthesis conditions, compare synthesis cost of18F-FESwith domestic and imported precursors, using synthetic productivity as index.3Improve quality control projects of18F-FES,establish its methodology of bacterialendotoxin.4Add18F-FES1.85×105Bq (5μCi) to mammary breast cells(MCF-10A) and breastcancer cells (MCF-7, MDA-MB-231) cultivated in vitro respectively,afterincubating for15,30,60,90,120,150min, measure radioactive count (CPM) withgamma radiation counter respectively to analyze18F-FES uptake of cells.5After treating MCF-7with different concentrations of ER antagonists Tamoxifen(TAM)(5,10and20mol/L) for24,48,72h, determine cell proliferation with MTTmethod; Add18F-FES1.85×105Bq (5μCi) to MCF-7treated with TAM10mol/Lfor72h, after incubating for60min,measure CPM with gamma radiation counterto analyze18F-FES uptake of cells; and measure estrogen receptor expression withimmunohistochemical technique(IHC). Results：1The important factors influencing the synthesis are: times of acetonitrile used>amount of precursor> temperature> amount of nuclide> hydrochloric acidconcentration; Synthetic productivity has nothing to do with the precursor sources.2According to the bacterial endotoxin inspection method builded, bacteria endotoxincontent of18F-FES injection should be lower than5EU/ml, bacterial endotoxin testisn,t interfered by1:10times of18F-FES diluent.3Three kinds of cells cultured in vitro all have obvious uptake of18F-FES, their18F-FES uptake values reach the peak after incubating for90min. The uptake valuesof ER positive breast cancer MCF-7cells are greater than those of ER negativeMDA-MB-231cells and MCF-10cells.4ER antagonists TAM significantly inhibites the proliferation of MCF-7cellsdependent on time and dose, the numbers of its cells decrease, as a result,its ERamounts also decrease,cell uptake values of18F-FES decrease obviously.Conclusions：1The synthesis productivity of18F-FES is high under the selected conditions,thedomestic precursor can replace imported one without affecting synthesis producivity,and synthetic cost can be significantly reduced; the bacterial endotoxinmethodology established and quality control projects improved can ensure thesafety and efficiency of18F-FES.218F-FES synthetised autonomously can combine with ER specifically.The18F-FESuptake values of cell lines in vitro relate to their ER expression levels.