Visualization of endogenous p53-mediated transcription in vivo using sodium iodide symporter.
OBJECTIVE
To develop a gamma camera imaging method for the determination of endogenous gene expression, we evaluated the expression of endogenous p53 gene using human sodium iodide symporter (hNIS) gene as reporter.


METHODS
We constructed cis-p53RE-hNIS reporter vector placed under control of an artificial enhancer (p53RE). Moreover, we transfected it into human hepatoma cell line SK-Hep1 by liposome. Geneticin was used for the selection of stable transfectant (SK-Hep1p53NIS). To evaluate the function of hNIS, the inhibition study was examined with 1 mmol/L potassium perchlorate. After treatment of Adriamycin with serial dose for 24 hours, we measured the uptake of 125I and did Western blot analysis to evaluate expression of p53 protein. Tumor xenografts were produced in nude mice by s.c. injection of SK-Hep1p53NIS cells. After 7 days, scintigraphic images of nude mice before and after Adriamycin treatment were obtained using [99mTc]-pertechnetate.


RESULTS
In the SK-Hep1p53NIS cells, Adriamycin-treated cells accumulated up to three times higher than did nontreated cells. Potassium perchlorate inhibited completely the uptake of 125I. As Adriamycin dose increased, radioiodide uptake was significantly correlated with activated p53 as well as total p53 protein level. When Adriamycin (2 mg/kg) was treated in the same mice, a significantly higher uptake of [99mTc]-pertechnetate was observed in SK-Hep1p53NIS xenografts compared with nontreated xenografts (P < 0.05, unpaired t test).


CONCLUSIONS
These results suggest that p53 expression level can be monitored by NIS gene expression using cis-p53RE-hNIS system in vitro and in vivo.
Kim
Kwang Il
KI
Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea.
Chung
June-Key
JK
Kang
Joo Hyun
JH
Lee
Yong Jin
YJ
Shin
Jae Hoon
JH
Oh
Hyun Jeong
HJ
Jeong
Jae Min
JM
Lee
Dong Soo
DS
Lee
Myung Chul
MC
D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D045744:Cell Line, Tumor; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D005822:Genetic Vectors; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010472:Perchlorates / Q000494:pharmacology; D010957:Plasmids / Q000378:metabolism; D017680:Potassium Compounds / Q000494:pharmacology; D011877:Radionuclide Imaging; D020133:Reverse Transcriptase Polymerase Chain Reaction; D027981:Symporters / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D015854:Up-Regulation; D000099209:Sodium-Iodide Symporters
D018076:DNA, Complementary; D004317:Doxorubicin; D005839:Gentamicins; D010472:Perchlorates; D017680:Potassium Compounds; D027981:Symporters; D016159:Tumor Suppressor Protein p53; D000099209:Sodium-Iodide Symporters; C009006:potassium perchlorate; C010680:antibiotic G 418