The In Vivo Study On Radioiodine Uptake In Hepatoma Cells Mediated By Recombinant Adenovirus Encoding Human Sodium Iodide Symporter Gene

Objective To investigate the feasibility of radioiodine therapy for hepatocellular carcinoma by using a recombinant adenovirus vector delivering human sodium iodide symporter gene into hepatoma cells .Methods HepG2 cells were s.c. injected into 20 male athymic nude mice Balb/c bilaterally with the concentration of 107 /100μl ( i.e. 107 cells in 100μl of sterile NS), when the tumor size reached 8~10mm in diameter (approximately two weeks after cells injection), the recombinant adenovirus vector AdhNIS was administrated into the right tumors of the nude mice (2.5×109 pfu in 50μl of PBS), enabling the infected tumor cells expression of NIS protein, wheras empty virus vector was administrated into the left tumors of the nude mice as a negative control. 72 hours after intratumoral injection, the I-131 imaging of the nude mice bearing subcutaneous hepatocellular carcinoma was taken by a gamma cammera, and the biodistribution of radioiodine at 1.5h,3h,6h,12h postinjection was investigated.Results Hepatocellular carcinoma xenograft models were successfully built at a percentage of 87.5% (i.e. 35/40). 1h after the administration of radioiodine via i.p. injection, the AdhNIS-treated tumor shows obvious radioactive uptake, wheras the control tumors were not visualized in the scintigraphy. The percentages of the total amount of injected radioiodine per gram of AdhNIS-treated tumor tissue were 8.21±0.77, 10.97±1.12, 5.86±0.83 and 2.41±0.66, respectively at 1.5h, 3h, 6h and 12h postinjection, %ID/g of the control tumors were 2.49±0.47, 1.58±0.38, 0.40±0.10 and 0.23±0.09, %ID/g of musles were 2.23±0.32,1.95±0.43,0.77±0.33 and 0.29±0.18. There is no significant difference between the control tumor and muscle, wheras %ID/g of the AdhNIS-treated tumor shows significant statistical difference compared with the control tumor and muscle.Conclusion Hepatocellular carcinoma can concentrate radioiodine in vivo after succefully transfected by recombinant adenovirus encoding human sodium iodide symporter gene, provide the basis for further study to demonstrate the feasibily of radioiodine therapy for nonthyroid tumors as hepatocellular carcinoma.