Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

EGP-2, also known as Ep-CAM, is expressed at high levels on the surface of most carcinomas and is therefore considered an attractive target for anticancer strategies. To explore the mechanisms regulating the expression of EGP-2, sequences 3.4 kb upstream of the transcription start site were isolated and assayed for their ability to control the expression of the EGP-2 cDNA, the green fluorescent protein, the luciferase reporter gene and the thymidine kinase and cytosine deaminase suicide genes. Expression of these chimeric constructs as assessed in a range of different cell lines was restricted to cell lines expressing EGP-2. In addition, only cells expressing EGP-2 were sensitive for gancyclovir after being transiently transfected with EGP-2 promoter-driven thymidine kinase. Deletion analyses defined 687 bp upstream as the basic proximal promoter region, which could confer epithelial-specific expression to the GFP reporter gene in vitro. As these EGP-2 sequences can confer promoter activity to reporter and suicide genes in an EGP-2 restricted manner, they may be useful for gene therapy of EGP-2 expressing carcinomas.
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PMID:Use of the EGP-2/Ep-CAM promoter for targeted expression of heterologous genes in carcinoma derived cell lines. 1524 30

Adenoviral vectors are widely used in cancer gene therapy. After systemic administration however, the majority of the virus homes to the liver and the expressed transgene may cause hepatotoxicity. To restrict transgene expression to tumor cells, tumor- or tissue-specific promoters are utilized. The tumor antigen epithelial glycoprotein-2 (EGP-2), also known as Ep-CAM, is expressed in many cancers from different epithelial origins. In this study, the EGP-2 promoter was shown to restrict the expression of luciferase and thymidine kinase in an adenoviral context in different cell lines. In vivo, the EGP-2 promoter mediated efficient expression of luciferase in tumors but showed a 3-log lower activity in liver tissue when compared with the cytomegalovirus (CMV) promoter. Similarly, the EGP-2 promoter mediated specific cell killing after ganciclovir treatment in EGP-2-positive cells. Moreover, in vivo, this treatment regiment did not cause any rise in the liver enzymes aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT), demonstrating absence of liver toxicity. In contrast, CMV-mediated expression of thymidine kinase in combination with ganciclovir treatment resulted in high ASAT and ALAT values. This study demonstrates the value of the EGP-2 promoter to restrict transgene expression to a broad range of tumor types, thereby preventing liver toxicity.
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PMID:The carcinoma-specific epithelial glycoprotein-2 promoter controls efficient and selective gene expression in an adenoviral context. 1609 50