The cellular oncogene EWS/activating transcription factor 1 is unable to activate adenovirus-borne promoters: implications for cytotoxic prodrug therapy of malignant melanoma of soft parts.
The cellular oncoprotein Ewing's sarcoma oncogene (EWS)/activating transcription factor 1 (ATF1) is a highly specific marker for malignant melanoma of soft parts (MMSP) and is a potent activator of several cAMP-inducible promoters, including the somatostatin promoter. Here we explored the potential for using the somatostatin promoter to direct toxic gene expression in MMSP cells. When introduced into MMSP cells, a somatostatin-herpes simplex virus thymidine kinase fusion gene confers strong and cell-specific sensitivity to the cytotoxic prodrug ganciclovir. Ganciclovir sensitivity requires the ATF-binding site present in the somatostatin promoter, indicating that toxic gene expression is caused by EWS/ATF1. We also tested the efficacy of recombinant adenoviruses adenoviruses for gene delivery and expression in two MMSP cell lines (DTC1 and Su-ccs-1). Surprisingly, several promoters (including somatostatin) that are strongly activated by EWS/ATF1 in transient assays are not activated in DTC1 and Su-ccs-1 cells when present in an adenovirus vector. In summary, our findings demonstrate the potential for using the somatostatin promoter for cytotoxic prodrug therapy for MMSP. However, first-generation adenovirus vectors cannot be used as promoter delivery vehicles for toxic gene expression in MMSP cells.
Lung
R W
RW
Department of Biology, Hong Kong University of Science and Technology, Kowloon, China.
Lee
K A
KA
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D015967:Gene Expression Regulation, Viral; D005822:Genetic Vectors / Q000627:therapeutic use; D006801:Humans; D015514:Oncogene Proteins, Fusion / Q000502:physiology*; D016716:PC12 Cells; D011355:Prodrugs / Q000627:therapeutic use*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D011995:Recombination, Genetic; D018227:Sarcoma, Clear Cell / Q000235:genetics* / Q000628:therapy* / Q000821:virology; D013004:Somatostatin / Q000235:genetics / Q000627:therapeutic use; D014157:Transcription Factors / Q000502:physiology*; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000235:genetics
C111598:EWS-ATF1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D011355:Prodrugs; D014157:Transcription Factors; D013004:Somatostatin