Preparation Of NY-ESO-1 MRNA Molecular Probes And Experimental Study Of Tumor SPECT Imaging

Objective:The experiment designed a novel molecular probe for labeling small interfering RNA（siRNA）with radionuclide ^99mTc targeting NY-ESO-1 to explore its application value in tumor gene imaging by studying the physicochemical and biological characteristics of the probe.Methods:Based on analyzing the differential expression of NY-ESO-1 gene in normal and tumor tissues in TCGA and GTEx databases;A375 cells with high expression of NY-ESO-1 and HCT116 cells with low expression were selected from the CCLE database.Three different siRNAs were designed,and the siRNA with the highest interference efficiency was selected for chemical modification.^99mTc labeling was performed to prepare 99m Tc-HYNIC-siRNA molecular probes.The labeling rate,radiochemical purity,and stability were tested.Cell uptake experiments,SPECT imaging,and biological distribution studies were conducted to detect the targeting of radiolabeled probes and their uptake in vivo and in vitro.Results:The expression level of NY-ESO-1 in breast cancer,colon cancer,liver cancer,lung adenocarcinoma,pancreatic cancer,skin melanoma,testicular cancer and thyroid cancer was significantly different from the corresponding normal tissues.The siRNA2 group had the highest interference efficiency.The labeling rate of radioactive probe 99m Tc-HYNIC-siRNA was 73.3±4.16%,and the radiochemical purity was 98.26±1.04%.The probe had good stability,and under various conditions,the radiochemical purity of the probe exceeded 85%within 6 hours.Liposomes could significantly increase the uptake rate of probes by cells,and under liposome mediated conditions,the uptake rate of A375 cells was significantly higher than that of HCT116 cells;however,there was no statistically significant difference in cell uptake rates between A375 and HCT116 under non liposome mediated conditions.SPECT imaging results showed that A375 tumor bearing mice showed clear tumor images,while HCT116 tumor bearing mice showed no radioactive concentration in the tumor tissue;the biological distribution results also showed that the radioactive uptake of tumor tissue in A375tumor bearing mice was significantly higher than that in HCT116 group.Conclusion:The ^99mTc-HYNIC-siRNA molecular probe successfully prepared in this experiment has a high labeling rate and radiochemical purity,exhibits good stability in vivo and in vitro,which is able to be ingested by tumor tissues with high expression of NY-ESO-1.It is a novel imaging molecular probe targeting tumor NY-ESO-1 mRNA,with potential application value.