[An in vitro study on radiation-induced TNF gene therapy of cancer].
TNF has certain radioprotective effect on host tissues and can enhance the antitumor effect of radiotherapy. In addition, the promoter region of Egr-1 gene can be activated by radiation. So a radiation-inducible, double copy retroviral vector expressing TNF named pETDC was constructed by fusing of Egr-1 promoter to hTNF-alpha gene. After packaged with Psi-2 and Crip cells, the virus titer in the supermatant was 4 x 10(5) CFU/ml. By infection with the virus supermatant and by G418 resistant selection, positive clones from murine fibroblast cells NIH3T3 and murine melanoma cells B16.F10 were obtained and found to secrete 2.1 ng/ml and 1.1 ng/ml TNF respectively. After 20 Gy radiation of the cells, the TNF levels secreted by the two positive clones were elevated to 13.8 ng/ml (6.6-fold) and 5.7 ng/ml (5.2-fold). Furthermore, hTNF-alpha expression was confirmed with RT-PCR. These in vitro data provide an experimental basis for the in vivo use of combination TNF gene therapy with local radiotherapy in cancer patients.
Cao
X
X
Department of Immunology, Second Military Medical University, Shanghai.
Zhang
W
W
Wang
J
J
D016475:3T3 Cells / Q000378:metabolism; D000818:Animals; D019677:Artificial Gene Fusion; D004268:DNA-Binding Proteins / Q000235:genetics*; D051766:Early Growth Response Protein 1; D015316:Genetic Therapy; D005822:Genetic Vectors; D017874:Immediate-Early Proteins; D008546:Melanoma, Experimental / Q000473:pathology; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000528:radiation effects; D012333:RNA, Messenger / Q000096:biosynthesis; D012190:Retroviridae / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics*
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha