%0 Journal Article %A Do Won Hwang %A Joo Hyun Kang %A Young Soo Chang %A Jae Min Jeong %A June-Key Chung %A Myung Chul Lee %A Soonhag Kim %A Dong Soo Lee %T Development of a Dual Membrane Protein Reporter System Using Sodium Iodide Symporter and Mutant Dopamine D2 Receptor Transgenes %D 2007 %R 10.2967/jnumed.106.036533 %J Journal of Nuclear Medicine %P 588-595 %V 48 %N 4 %X For noninvasive monitoring of cellular status by dual reporters, a dual membrane protein reporter system was developed and its in vivo applicability was examined. Human sodium iodide symporter (hNIS) and mutant dopamine D2 receptor (D2R) transgenes were chosen considering their complementarity. Methods: pIRES-hNIS/D2R containing NIS and D2R linked with an internal ribosomal entry site (IRES) was constructed and transfected into human hepatoma SK-Hep1 and rat glioma C6 cells. The cell lines stably expressing hNIS and D2R (named SK-ND and C6-ND) were produced, which was confirmed by messenger RNA expression of reporter genes. The functional activities of hNIS and D2R were measured by 125I uptake assay and 3H-spiperone receptor-binding assays. A biodistribution study was performed on SK-ND tumor-bearing mice using 99mTc-pertechnetate and 3H-spiperone. In vivo hNIS expression was examined using 99mTc-pertechnetate γ-camera imaging and, D2R expression was examined using a 3H-spiperone autoradiographic study. Results: 125I uptake of SK-ND and C6-ND cell lines showed a maximum 97-fold and 43-fold increase, respectively, which were completely inhibited by KClO4. Specific 3H-spiperone binding to SK-ND and C6-ND cell homogenates was observed, which were completely inhibited by (+)-butaclamol. Among the dual reporter gene−expressing cell lines, the activities of both reporters were inversely correlated with each other. Competition assay of hNIS-expressing cells by D2R vector transfection and D2R-expressing cells by hNIS vector transfection showed a dose-dependent decrease of hNIS and D2R activities, respectively. In the biodistribution study, 99mTc-pertechnetate accumulated 10-fold and 3H-spiperone accumulated 4-fold more in SK-ND tumors than that in parental SK tumors. In vivo imaging of 99mTc-pertechnetate persisted until 5 wk after the cell graft in SK-ND tumors. Autoradiographic study of brain tissues from these mice also revealed an accumulation of 3H-spiperone in SK-ND tumors. Conclusion: We developed a dual membrane-bound positron and γ-imaging reporter system of hNIS and D2R. We observed its reporting capability in vitro and in vivo and elucidated that these 2 membrane protein reporters competed with each other in their expression. Although we expect that hNIS and D2R transgenes can complement each other as a dual reporter system, we suggest that one needs to validate the ratio of expression of the 2 membrane protein reporter transgenes for cellular status tracking. %U https://jnm.snmjournals.org/content/jnumed/48/4/588.full.pdf