Tumor-specific Gene Therapy for Renal Cell Carcinoma Using MN/CA9-directed Replication-competent Adenovirus / 대한비뇨기과학회지

PURPOSE: A new therapeutic approach is needed in patients with metastatic renal cell carcinoma (RCC) because of a dismal prognosis. MN/CA9 is a transmembrane glycoprotein that was first identified in the human cervical carcinoma cell line, HeLa. Since MN/CA9 protein is highly expressed in RCC tissues, but not in normal kidney, we constructed a tumor-specific replication-competent adenoviral vector utilizing MN/CA9 promoter (Ad-MN/CA9-E1a) and demonstrated its selective cytotoxicity toward MN/CA9-expressing RCC cells in vitro. MATERIALS AND METHODS: MN/CA9-positive (HeLa, SK-RC-52) and MN/ CA9-negative (SK-RC-29) cells were used. RT-PCR assay for MN/CA9 mRNA was performed in each cells. Ad5 E1a protein production in each cells after infection with Ad-MN/CA9-E1a was determined by western blot analysis. In vitro cytotoxicity assay was performed for assessing the selective cytotoxicity of Ad-MN/CA9-E1a to MN/CA9-expressing cells. RESULTS: RT-PCR assay showed that a distinct 255-bp fragment corresponding to the sequence within MN/CA9 cDNA was detected in HeLa and SK-RC-52 cells, but SK-RC-29 cells did not have MN/CA9 transcripts. Western blot analysis demonstrated that HeLa and SK-RC-52 cells showed much stronger Ad5 E1a protein expressions compared with SK-RC-29. In vitro cytotoxicity assay revealed that the growth of MN/CA9-positive cells was significantly inhibited with 0.1-1MOI of Ad-MN/CA9-E1a, but the growth of MN/CA9-negative cells (SK-RC-29) could only be inhibited by as many as 100MOI. CONCLUSIONS: These results suggest that a novel replication-competent adenoviral vector mediated by MN/CA9 promoter, Ad-MN/CA9-E1a, can selectively replicate in MN/CA9-expressing cancer cells with cytotoxic effects and may be utilized for the treatment of RCC.

Suicide Gene Therapy for Bladder Cancer Using a Recombinant Adenovirus Expressing Escherichia Coli Cytosine Deaminase / 대한비뇨기과학회지

PURPOSE: The poor prognosis of advanced bladder cancer requires the investigation of novel treatment modalities. In this study, we investigated the suicide gene therapy for bladder cancer, using the adenovirus-mediated expression of Escherichia coli cytosine deaminase (CD) in conjunction with the prodrug 5-fluorocytosine (5-FC). MATERIALS AND METHODS: A replication-deficient recombinant adenovirus, which contains the Rous sarcoma virus (RSV) promoter driving the expression of CD, (Ad-RSV-CD) was constructed. In vitro cell-killing assay, using Ad-RSV-CD (20 MOI) plus 5-FC (500muM), was performed in bladder cancer cell lines, HT-1376, UM-UC-3 and NBT-II. The CD enzymatic activity was measured in the Ad-RSV-CD (20 MOI) infected cells, and the concentrations of 5-fluorouracil (5-FU) yielding an IC50 were calculated for those cells. RESULTS: 5-FU dose response curve showed that IC50 of NBT-II was 0.8muM, HT-1376 1.0muM and UM-UC-3 5.1muM at day 6. The CD enzymatic activities of the Ad-RSV-CD infected UM-UC-3, HT-1376 and NBT-II cells were 5696, 4655, 1766 pmole/1x10(6) cells, respectively. Whereas the administration of 5-FC (500muM) or Ad-RSV-CD (20 MOI) alone demonstrated no cytotoxicity to cells, Ad-RSV-CD/5-FC exhibited a significant cytotoxic effect in the cells, especially the UM-UC-3 and HT-1376. CONCLUSIONS: Ad-RSV-CD/5-FC suicide gene therapy is effective for bladder cancer cells in cell cultures, suggesting this approach may have potential as a strategy for the treatment of bladder cancer.