| Objective To establish a novel nano-particle GLUT1-Ag@Mn-siRNA and explore its role in labeling pancreatic cancer cells as well as the changes of signal intensity in 3.0T MRI imaging and as a sensitizer to improves the radiosensitization of tumors.Methods Single stranded DNA used as template to synthetic nucleic acid silver nanocluster.GLUT1-Ag@Mn nano probe was formed by base complementary pairing principle and electrostatic adsorption coupling of GLUT1 aptamers,Mn ions and Cy5.5.TEM was used to access the uniformity and dispersion of nano-particle.Mouse embryo fibroblast and human pancreatic cancer cells were incubated with different concentrations of GLUT1-Ag@Mn nanoparticles for 72 hours.CCK-8 was used to access the proliferation of the cells.The hemolysis tests was used to characterize the blood compatibility.HE stain test was performed to observe the histomorphology.The confocal laser scanning microscope was used to test the targeting property of the prob.In vivo and in vitro MRI imaging was used to access the target specifically and signal change of T1 WI.Linked siRNA to preparation GLUT1-Ag@Mn-siRNA nano probe,Westen blot and PCR test were used to verify the effect of the prob.The radiosensition of probs was investigated by clonogenic assay,CCK-8 test,transwell test and flow cytometry test in vitro.Using tumor-bearing nude mice to verify the radiosensitizing effect of nano-probe in vivo.Results TEM results suggest that the GLUT1-Ag@Mn nano probe has good water-solubility,high dispersion,small size and a better homogeneity.The results of CCK-8 showed that the cell survival rate of each group was higher than that of 90%,and there was no significant difference in cell survival rate among the groups(P>0.05).The hemolysis tests was showed that the probs caused no obvious hemolysis while under 2μmol/L.And HE stain test was showed the probs caused no inflammation and necrosis.The confocal laser scanning microscope had observed that PaTu 8988 cells absorbed more probs.MRI TIWI in vitro and in vivo test shows that the nano-particle can enhance the signal of T1 WI.Westen blot and PCR test results suggest than the prob can interfere HIF-1α.CCK-8test results showed that tumor cell survival rate decreased by 20.5%(P<0.05).The colony-forming efficiency,transwell test and flow cytometry test results suggest that the malignant degree of the cancer cells was declined and the percentage of apoptosis cell was 29.84%(P<0.01).The results of in vivo experiments showed that the tumor volume of the control group was significantly increased,and the tumor volume in the radiotherapy alone group was inhibited,which reduced the tumor growth significantly by 48%.The tumor volume of the Glut1-Ag@Mn-sirna combined with radiotherapy group was reduced by 66%.Conclusions GLUT1-Ag@Mn-siRNA nano-particle has good physic-chemical properties.It can detect pancreatic cancer cells with high expression of GLUT1 and enhance the signal of T1 WI.It is expected to provide evidence for the early diagnosis of pancreatic cancer,meanwhile,the nano probe has the effects of increasing the sensitivity of hypoxic tumor to radiotherapy by down-regulating the expression of HIF-1α,so it is an ideal radiosensitizer. |
