acyclovir and Urinary-Bladder-Neoplasms

The most extensively investigated strategy of suicide gene therapy for treatment of cancer is the transfer of the herpes simplex virus thymidine kinase (HSV-TK) gene followed by administration of antiviral prodrugs such as acyclovir (ACV) and ganciclovir (GCV). The choice of the agent that can stimulate HSV-TK enzymatic activity is one of the determinants of the usefulness of this strategy. Previously, we found that a diterpenoid, scopadulciol (SDC), produced a significant increase in the active metabolite of ACV. This suggests that SDC may play a role in the HSV-TK/prodrug administration system.. The anticancer effect of SDC was evaluated in HSV-TK-expressing (TK+) cancer cells and nude mice bearing TK+ tumors. In vitro and in vivo enzyme assays were performed using TK+ cells and tumors. The phosphorylation of ACV monophosphate (ACV-MP) was measured in TK- cell lysates. The pharmacokinetics of prodrugs was evaluated by calculating area-under-the-concentration-time-curve values.. SDC stimulated HSV-TK activity in TK+ cells and tumors, and increased GCV-TP levels, while no effect of SDC was observed on the phosphorylation of ACV-MP to ACV-TP by cellular kinases. The SDC/prodrug combination altered the pharmacokinetics of the prodrugs. In accord with these findings, SDC enhanced significantly the cell-killing activity of prodrugs. The bystander effect was also significantly augmented by the combined treatment of ACV/GCV and SDC.. SDC was shown to be effective in the HSV-TK/prodrug administration system and improved the efficiency of the bystander effect of ACV and GCV. The findings will be considerably valuable with respect to the use of GCV in lower doses and less toxic ACV. This novel strategy of drug combination could provide benefit to HSV-TK/prodrug gene therapy.

Topics: Abietanes; Acyclovir; Animals; Antiviral Agents; Biological Availability; Carcinoma; Cell Line, Tumor; Female; Ganciclovir; Genes, Neoplasm; Genetic Therapy; Glioblastoma; HeLa Cells; Herpes Simplex; Herpesvirus 1, Human; Humans; Laryngeal Neoplasms; Mice; Mice, Nude; Molecular Structure; Plasmids; Prodrugs; Thymidine Kinase; Transfection; Urinary Bladder Neoplasms; Xenograft Model Antitumor Assays

Topics: Acyclovir; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Carcinoma, Transitional Cell; Cisplatin; Combined Modality Therapy; Drug Eruptions; Female; Fluorouracil; Humans; Interferons; Middle Aged; Urinary Bladder Neoplasms

To develop a new toxic gene therapy using the tissue-specific human chorionic gonadotropin-beta (hCG-beta) promoter for testicular cancer. Although most patients presenting with disseminated testicular tumor are cured through the use of chemotherapy with or without surgery, those patients with relapse after initial therapy present a difficult clinical problem. The serum tumor marker hCG-beta is frequently elevated in patients with testicular cancer, and the pretreatment and post-treatment levels of serum hCG-beta are highly predictive of treatment outcome.. Human testicular embryonal carcinoma cell line, NEC 8, a human prostate cancer cell line, PC-3, and a human bladder cancer cell line, WH, were used in this study. A transient expression experiment was used to analyze the activity of a 729-bp hCG-beta promoter in all three cell lines. A recombinant adenovirus carrying thymidine kinase (Ad-hCG-beta-TK) under control of the hCG-beta promoter was generated. The tissue-specific activity of Ad-hCG-beta-TK was tested in vitro and in vivo.. The hCG-beta promoter had significantly greater activity in the hCG-beta-producing cell line (NEC 8) than in the non-hCG-beta-producing cell lines (PC-3 and WH). In vitro, Ad-hCG-beta-TK with acyclovir significantly inhibited NEC 8 growth but not PC-3 or WH cell growth. In vivo, Ad-hCG-beta-TK with acyclovir significantly inhibited NEC 8 subcutaneous tumor growth in nude mice.. In this study, we explored the possibility of developing a new therapeutic agent to target and induce the killing of testicular germ cell tumor selectively by using tissue-specific hCG-beta promoters.

Topics: Acyclovir; Adenoviridae; Animals; Biomarkers, Tumor; Carcinoma; Carcinoma, Embryonal; Cell Line, Tumor; Chorionic Gonadotropin, beta Subunit, Human; Enzyme Inhibitors; Genes, Transgenic, Suicide; Genetic Therapy; Genetic Vectors; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Proteins; Prodrugs; Promoter Regions, Genetic; Prostatic Neoplasms; Recombinant Fusion Proteins; Salvage Therapy; Testicular Neoplasms; Thymidine Kinase; Urinary Bladder Neoplasms; Xenograft Model Antitumor Assays

N-Nitrosobutyl(4-hydroxybutyl)amine (BBN) is a selective bladder carcinogen in rats. Its organ specificity may depend on several factors, including metabolic activation, DNA alkylation and repair within the target organ. Metabolic activation of BBN, which is asymmetrical, may result in butylating and 4-hydroxybutylating species. To test this view, BBN was administered as a single oral dose of 20 or 120 mg/rat or six doses of 20 mg/rat over 2 weeks. The animals given the single 120 mg dose were killed 3, 6 and 24 h after treatment. Rats given 20 mg or 6 x 20 mg BBN were killed 24 h after the last dose. DNA from liver and urothelial cells was hydrolyzed and analyzed for O6-butylguanine (O6-BuG) and O6-(4-hydroxybutyl)guanine [O6-(4-OH-Bu)G] as their pentafluorobenzyl-trimethylsilyl derivatives by high-resolution gas chromatography--negative ion chemical ionization mass spectrometry with selective ion recording after immunoaffinity extraction. Polyclonal antibodies raised against O6-(4-hydroxybutyl)-guanosine [O6-(4-OH-Bu)GR] were coupled to CNBr-activated Sepharose 4B. This was mixed with a gel coupled to antibodies raised against O6-BuG, already available in the laboratory, and the mixed gel was used for the one-step sample clean-up, enrichment and extraction of O6-(4-OH-Bu)G and O6-BuG from hydrolyzed DNA. O6-BuG in urothelial DNA of rats given a single dose of 120 mg BBN increased from 0.44 +/- 0.12 mumol/mol guanine (mean +/- SE) 3 h after treatment, to 17.9 +/- 7.23 mumol/mol guanine at 24 h. O6-(4-OH-Bu)G in the same tissue was 7.7 +/- 3.19 mumol/mol guanine 3 h after treatment and 12.2 +/- 7.01 mumol/mol guanine at 24 h. O6-BuG and O6-(4-OH-Bu)G were always lower in the liver than in urothelial cells. Twenty-four hours after a single dose of 20 mg BBN, urothelial O6-BuG was 5.41 +/- 1.73 mumol/mol guanine and did not accumulate after six doses of 20 mg/rat BBN, since it was 2.59 +/- 1.23 mumol/mol guanine 24 h after the last dose. O6-BuG in liver DNA was detectable after the single dose of 20 mg, but not after 6 x 20 mg/rat BBN. O6-(4-OH-Bu)G was not detected in either the bladder or the liver after 20 mg or after the six doses of BBN.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Acyclovir; Animals; Antibodies; Antibody Specificity; Butylhydroxybutylnitrosamine; DNA; DNA Damage; Enzyme-Linked Immunosorbent Assay; Guanine; Liver; Male; Mass Spectrometry; Rabbits; Rats; Rats, Inbred Strains; Urinary Bladder; Urinary Bladder Neoplasms