The objective of this proposal is to investigate the mechanism of ganciclovir cytotoxicity and the """"""""bystander effect"""""""" in two human colon carcinoma cell lines (HT29, SW620) expressing herpes simplex virus thymidine kinase. Preliminary experiments revealed differential sensitivity to ganciclovir between cell lines, as well as divergent capacities for intercellular communication. The initial aim will define which elements are responsible for the cytotoxic activity of ganciclovir and determine why one cell line is more or less sensitive to this therapy. A comparison between these two cell lines will be used to determine a relationship between ganciclovir metabolism, its consequences on DNA synthesis and integrity and its effect on bystander killing. Subsequent studies will focus on enhancing bystander killing by manipulating HSV-tk expression, endogenous dNTP pools and gap junctional intercellular communication.
| Boucher, P D; Ostruszka, L J; Murphy, P J M et al. (2002) Hydroxyurea significantly enhances tumor growth delay in vivo with herpes simplex virus thymidine kinase/ganciclovir gene therapy. Gene Ther 9:1023-30 |
| Boucher, P D; Ostruszka, L J; Shewach, D S (2000) Synergistic enhancement of herpes simplex virus thymidine kinase/ganciclovir-mediated cytoxicity by hydroxyurea. Cancer Res 60:1631-6 |
| Rubsam, L Z; Boucher, P D; Murphy, P J et al. (1999) Cytotoxicity and accumulation of ganciclovir triphosphate in bystander cells cocultured with herpes simplex virus type 1 thymidine kinase-expressing human glioblastoma cells. Cancer Res 59:669-75 |
| Boucher, P D; Ruch, R J; Shewach, D S (1998) Differential ganciclovir-mediated cytotoxicity and bystander killing in human colon carcinoma cell lines expressing herpes simplex virus thymidine kinase. Hum Gene Ther 9:801-14 |
