24 research outputs found
Gene Therapy for the Treatment of Recurrent Pediatric Malignant Astrocytomas with In Vivo
Selective Killing of Human Immunodeficiency Virus-Infected Cells by Targeted Gene Transfer and Inducible Gene Expression Using a Recombinant Human Immunodeficiency Virus Vector
Thymidine Kinase Gene Therapy for Human Malignant Glioma, Using Replication-Deficient Retroviruses or Adenoviruses
Liver Failure Caused by Herpes Simplex Virus Thymidine Kinase Plus Ganciclovir Therapy Is Associated with Mitochondrial Dysfunction and Mitochondrial DNA Depletion
Hexokinase Type II: A Novel Tumor-Specific Promoter for Gene-Targeted Therapy Differentially Expressed and Regulated in Human Cancer Cells
Multi-Log Cytotoxicity of Carbocyclic 2′-Deoxyguanosine in HSV-TK-Expressing Human Tumor Cells
Ganciclovir (GCV) is widely used as a prodrug for selective activation in tumor cells expressing herpes simplex virus thymidine kinase (HSV-TK) because of its ability to induce multi-log cytotoxicity to HSV-TK-expressing as well as nonexpressing bystander cells. We now report that another substrate for HSV-TK, D-carbocyclic 2′-deoxyguanosine (CdG), induces multi-log cytotoxicity in HSV-TK-expressing and bystander cells at concentrations ≤3 μM. We have compared the cytotoxicity and cell cycle effects of CdG to that observed with GCV in two human tumor cell lines. The results demonstrated that cytotoxicity of CdG was similar to that of GCV in both U251 glioblastoma and SW620 colon carcinoma cells that stably expressed HSV-TK. In addition, CdG induced a potent bystander effect in both cell types in co-cultures consisting of HSV-TK-expressing and nonexpressing bystander (lacZ-expressing) cells at ratios of 50:50 or 10:90. Selectivity for HSV-TK-expressing compared to lacZ-expressing cells was similar for CdG and GCV in the U251 cells, however CdG was less selective than GCV in the SW620 cell lines. Despite their ability to induce multi-log cytotoxicity at similar concentrations, CdG and GCV exhibited differential effects on cell cycle progression. Cells incubated with 1 μM CdG for 24 hr accumulated in S-phase and G2/M after drug washout, and the majority of cells died prior to cell division. This contrasts with the delayed effects of 1 μM GCV that were not evident until after cell division when cells attempted S-phase for the second time. Thus, CdG is a potent cytotoxic agent that merits further investigation to determine whether it will be therapeutically effective in enzyme-prodrug therapy with HSV-TK.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63436/1/10430340252809838.pd