USE OF A TISSUE-SPECIFIC PROMOTER FOR TARGETED EXPRESSION OF THE HERPES-SIMPLEX VIRUS THYMIDINE KINASE GENE IN CERVICAL-CARCINOMA CELLS

Molecular chemotherapy strategies have been developed for a number of epithelial malignancies based on selective delivery and expression of a toxin-encoding gene into the cancer cells. To date, these strategies have not been explored in the context of carcinoma of the cervix, des pite the fact that a variety of factors suggest this as an appropriate disease for this gene therapy approach. One limitation in this respec t is that appropriate tissue-specific promoters for selective toxin ge ne expression have not been defined for cervical carcinoma. in this re gard, the secretory leukoprotease inhibitor (SLPI) gene has been shown to be constitutively expressed in many epithelial carcinoma cells inc luding the uterine cervix. Thus, we investigated the utility of the SL PI gene as a tissue-specific promoter for regulatory control of the he rpes simplex virus thymidine kinase gene for in vitro treatment of cer vical carcinoma cells. For this analysis, a gene construct was derived with the herpes simplex virus thymidine kinase gene under regulatory control of the 5' upstream regions of the SLPI gene. Transient transdu ction of three human cervical carcinoma cell lines with the SLPI-thymi dine kinase (TK) construct was followed by treatment with the prodrug ganciclovir. Crystal violet staining was subsequently used to assess c ell viability. In this analysis, it was shown that the SLPI-TK constru ct directed TK-mediated killing in two of three tested cervical cell l ines, with the two cell lines being positive for SLPI. in addition, mi xing experiments established that cervical carcinoma cells could exhib it a bystander effect which potentially augments the efficacy of molec ular chemotherapy approaches. These findings may allow for the develop ment of efficacious, target-specific, toxin gene therapy strategies fo r cervical carcinoma in human patients.