Preparation of MRI molecular probe targeting human epidermal growth factor receptor 2 and the ;preliminary study of breast cancer cell in vitro / 中华放射学杂志

ABSTRACT

Objective To develop a superparamagnetic iron oxide nanoparticles ( SPIO ) based on MRI probe specifically targeting human epidermal growth factor receptor 2 (HER2) and explore its value as MRI positive contrast agents in vitro.Methods (1) The superparamagnetic iron oxide ( PS) was obtained by means of classical coprecipitation in polylactic acid solution , then coupled with fluorescein isothiocyanate (FITC) labeled LTVSPYW to develop the targeted probe ( FITC-LTVSPWY-PS).The particle size was measured under transmission electron microscope.Relaxation rate was detected by 3.0 T MR scanner.(2) Climbing films of human breast cancer cell MCF-7 were prepared and incubated with FITC-LTVSPWY-SPIO, then fluorescence distribution was observed under inverted microscope.And distribution of iron particles was confirmed by prussian blue staining.(3) MCF-7 and MDA-MB-231 cells were incubated with FITC-LTVSPWY-SPIO and PS, respectively.MCF-7 incubated with FITC-LTVSPWY-PS were used as experimental group, MCF-7 treated with PS as control group , and cells added with nothing as blank group.There were 3 samples in each group.The MR imaging was performed only once and T 2 WI signal intensity of cells was recorded.The comparison of T 2 signal intensity among groups was conducted by using one-way ANOVA.Results The core and surface size of nanoparticles were (13.9 ±1.6) nm and (122.0 ±5.5) nm respectively.Zeta potential and relaxation rate of the FITC-LTVSPWY-PS were ( -30.7 ±2.2 ) mV and 70.7 m· M-1 · s-1 respectively, and the PS were (28.1 ±2.8) mV and 72.1 m· M-1 · s-1 respectively.The fluorescence could be seen on the surface of MCF-7 cells, and the prussian blue staining showed that FITC-LTVSPWY-PS could specifically target HER 2-positive cells.The low signal on T 2 WI was observed in MCF-7 cells incubated with FITC-LTVSPWY-PS, whereas cells treated with PS and blank group showed equal signals , the T2 values were ( 61.8 ±5.7 ) , ( 101.6 ±2.5 ) and ( 103.5 ±1.9 ) ms respectively.Significant difference existed among these groups ( F =355.698, P <0.05 ).Conclusions The MR targeting probe FITC-LTVSPWY-PS was prepared successfully , its physical characterization and magnetic properties could target the HER 2 highly expressing on the surface of breast cancer cells and meet the need of targeted imaging.It provides an important tool for MR molecular imaging.