[Expression of the radio-inducible TK suicide gene controlled by Egr-1 promoter in pancreatic cancer cells: an in vitro experiment].
OBJECTIVE
To investigate the expression of radio-inducible herpes simplex virus thymidine kinase (TK) suicide gene controlled by early growth response-1 (Egr-1) promoter in pancreatic cancer cells.


METHODS
Adenoviral vector pAdEgr-1-TK containing green fluorescent protein (GFP) was constructed. Human pancreatic cancer cells of the line PC-3 were cultured, transfected with pAdEgr-1-TK, and then exposed to 60Co source gamma-radiation at the doses of 0, 5, 7.5, 10, 15, and 20 Gy respectively for 24 hours. RT-PCR and Western blotting were used to detect the TK mRNA and protein expression in the PC3 cells.


RESULTS
The TK mRNA expression levels of the PC3 cells exposed to y-radiation at the doses of 0, 5, 7.5, 10, 15, and 20 Gy respectively were (67.3 +/- 2.1)%, (89.3 +/- 1.0)%, (114.7 +/- 5.7)%, (140.5 +/- 3.1)%, (134.5 +/- 4.0)%, and (117.4 +/- 3.4)% respectively. The TK mRNA expression level was markedly increased after exposure to gamma-radiation, especially that t the dose of 10 Gy (all P < 0.01). The TK protein expression levels of the PC3 cells exposed to y-radiation at the doses of 0, 5, 7.5, 10, 15, and 20 Gy were (5.4 +/- 0.7)%, (7.6 +/- 0.9)%, (21.5 +/- 1.5)%, (35.7 +/- l1.4)%, (32.1 +/- 1.2)%, and (28.8 +/- 1.5)% respectively.


CONCLUSIONS
The Egr-1 promoter causes high expression of TK suicide gene in cancer cells after exposure to 60Co-gamma-radiation. These data provide an experimental basis for gene therapy.
Liu
Jin-long
JL
Department of General Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Liu
Xun-liang
XL
Qian
Qing
Q
Du
Qing
Q
Guo
Shi-ying
SY
Li
Chao-jun
CJ
Miao
Yi
Y
D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D051766:Early Growth Response Protein 1 / Q000235:genetics*; D015870:Gene Expression / Q000528:radiation effects; D041722:Genes, Transgenic, Suicide / Q000235:genetics*; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018139:Simplexvirus / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
D051766:Early Growth Response Protein 1; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D013937:Thymidine Kinase