Preparation and characterization of dual-modality molecular probes for imaging angiogenesis of gastric cancer / 中华放射学杂志

ABSTRACT

Objective To develop an MR optical dual-modality probe targeting angiogenesis of gastric cancer and to study its physical characteristics , in vitro cytotoxicity and magnetic effects of different pulse sequences on 3 T clinical MR scanner.Methods We conjugated GX1-Cy5.5, a novel gastric cancer neo-vasculature targeted peptide labeled with Cy 5.5, to the surface functionalized magnetic nanoparticles according to different molecular weights (1∶100, 1∶500),resulting in dual-modality probe DPs100 and DPs500 (named DPs).The hydrodynamic size and zeta potential of DPs and DPs 500 were analyzed by nano-ZS.The human umbilical vein endothelial cells (HUVECs) and BGC-823 cells were treated with DPs for 24 h, and methyl thiazol tetrazolium ( MTT) method was used to detect the survival rate of cells.DPs with different concentrations were scanned on different MR sequences , and then the relative signal intensity was observed.The absorbance of HUVECs and BGC823 cells treated with DPs of different concentration (0.00, 1.25, 2.50, 15.00, 50.00, 100.00 and 150.00 μg/ml) were compared with single factor analysis of variance.Relative signal intensity of different MR sequences was compared using a paired Wilcoxon signed-rank test.Results The dual-modality probe targeting angiogenesis of gastric cancer was successfully constructed.The hydrodynamic size of iron oxide nanoparticles , DPs100 and DPs500 was (35.23 ±0.07), (39.49 ±0.16) and (40.43 ±1.70) nm and the Zeta potential was (0.31 ±0.20), ( -4.15 ±0.79) and ( -10.51 ± 2.37) mV.The coupled rates of DPs 100 and DPs500 with polypeptide were 92%and 94% respectively.The absorbance of HUVECs and BGC823 cells treated with DPs of different concentrations were 0.76 ±0.04, 0.80 ±0.03, 0.79 ±0.05, 0.75 ±0.06, 0.74 ±0.05, 0.77 ±0.01,0.71 ±0.04 and 0.38 ±0.04, 0.43 ±0.04, 0.41 ±0.03, 0.43 ±0.07, 0.44 ±0.04, 0.41 ±0.07 and 0.40 ±0.04, there was no statistical significance ( F=0.94, 0.51;P>0.05).The signal intensity increased first and then decreased following the increasing concentrations of DPs on T 1WI,especially on FSPGR T1WI (Z =-3.294,P 10μg/ml( Z=-7.110,P>0.05).With iron concentration≤10 μg/ml,the signal intensity on SSFSE T 2*WI was significantly decreased compared to FSE T2 WI ( Z =-2.023, P <0.05 ) .Conclusions DPs may be potential dual-modal probes for characterization of tumor angiogenesis by MR and optical imaging noninvasively , without causing significant effects on the cell activity in vitro , and SSFSE T2*WI may be the most sensitive sequence for DPs evaluation on MR.