Cytotoxicity of adenoviral-mediated cytosine deaminase plus 5-fluorocytosine gene therapy is superior to thymidine kinase plus acyclovir in a human renal cell carcinoma model

Shirakawa, T Gardner, TA Ko, SC Bander, N Woo, S Gotoh, A Kamidono, S Chung, LWK Kao, C

T. Shirakawa et al., Cytotoxicity of adenoviral-mediated cytosine deaminase plus 5-fluorocytosine gene therapy is superior to thymidine kinase plus acyclovir in a human renal cell carcinoma model, J UROL, 162(3), 1999, pp. 949-954

39

INGLESE

Article

Urology & Nephrology","da verificare

JOURNAL OF UROLOGY

0022-5347 → ACNP

162

3

1999

1

949 - 954

ISI

0022-5347(199909)162:3<949:COACDP>2.0.ZU;2-O

Purpose: An estimated 11,600 Americans will die of renal cell carcinoma in 1998. The lack of effective chemotherapy or radiotherapy requires the inves tigation of novel treatment modalities. We compared two forms of toxic gene therapy, cytosine deaminase (CD) plus 5-fluorocytosine (5-FC) and thymidin e kinase (TK) plus acyclovir (ACV), in pre-clinical models of human renal c ell carcinoma. Materials and Methods: Replication-deficient recombinant adenoviral vectors containing the Rous sarcoma virus promoter driving CD (Ad-RSV-CD) or TK (A d-RSV-TK) gene expression were constructed and tested for in vitro cell-kil ling assays at various viral multiplicity of infection (MOI) and in vivo fo r growth inhibition of a human renal cell carcinoma, SK-RC-29 models. Subcu taneous tumors of SK-RC-29 were examined by electron microscopy for presenc e of intercellular gap junctions. Levels of expression of the gap junctiona l associated connexin 43 protein in SK-RC-29, 31, 38, 42, 52 human RCC cell lines were examined by western immunoblotting. Results: In vitro cell-killing assay comparing Ad-RSV-CD/5F-C and Ad-RSV-TK /ACV at a wide range of MOI (2.5 to 20) revealed superior cell-kill by Ad-R SV-CD/5-FC over Ad-RSV-TK/ACV. Consistent with these results, we observed t hat Ad-RSV-CD/5-FC but not Ad-RSV-TKIACV demonstrated a significant in vivo tumor growth inhibition. These results are corroborated by the lack of gap junctions in SK-RC-29 subcutaneous tumors by the electron microscopy and t he absence of connexin-43 in all five human RCC cell lines by western immun oblotting. Conclusion: We have demonstrated in this study that Ad-RSV-CD/5-FC is super ior to Ad-RSV-TK/ACV for the treatment of human RCC in cell culture and ani mal models. The results are supported by the lack of gap junctional communi cation between RCC cells assessed by connexin-43 expression.