Highly efficient gene delivery for bladder cancers by intravesically administered replication-competent retroviral vectors.
OBJECTIVE
In an attempt to improve viral delivery of potentially therapeutic genes via an intravesical route, we have recently developed murine leukemia virus-based replication-competent retrovirus (RCR) vectors.


METHODS
We evaluated the transduction efficiency of intravesically administered RCR vectors to bladder tumor using orthotopic animal models to determine their potential as delivery vectors for bladder cancer.


RESULTS
The RCR vector containing green fluorescent protein (GFP) marker gene achieved efficient in vitro transmission of the GFP transgene. Murine bladder tumor-2 mouse bladder tumors exposed to intravesically administered RCR vectors exhibited 0%, 9.2 +/- 2.9%, and 30.0 +/- 6.2% of GFP expression at 9, 18, and 27 days after exposure in the orthotopic model, respectively. Orthotopic KU-19-19 human bladder tumors exposed to intravesically administered RCR vectors exhibited 3%, 85 +/- 1.0%, and 100% of GFP expression at 7, 21, and 35 days after exposure, respectively. GFP staining was observed only in the tumor cells in the bladder. No detectable PCR products of GFP gene could be observed in distant organs. Treatment with RCR vectors containing yeast cytosine deaminase (CD) gene plus 5-fluorocytosine (5-FC) dramatically inhibited the growth of preestablished murine bladder tumor-2 tumors. A single course of 5-FC treatment resulted in a 50% animal survival in mice exposed to RCR-CD compared with a 0% survival in all controls over a 70-day follow-up period.


CONCLUSIONS
Intravesically administered RCR vectors can efficiently deliver genes to orthotopic bladder tumor without viral spread in distant organs. RCR-CD/5-FC suicide gene therapy promises to be a novel and potentially therapeutic modality for bladder cancer.
Departments of Urology and Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
Eiji
E
Kikuchi
Silvia
S
Menendez
Choichiro
C
Ozu
Makoto
M
Ohori
Carlos
C
Cordon-Cardo
Christopher R
CR
Logg
Noriyuki
N
Kasahara
Bernard H
BH
Bochner
D000283:Administration, Intravesical; D000818:Animals; D000963:Antimetabolites / Q000008:administration & dosage; D043525:Cytosine Deaminase / Q000008:administration & dosage; D005260:Female; D005437:Flucytosine / Q000008:administration & dosage; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000627:therapeutic use*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D009052:Leukemia Virus, Murine / Q000235:genetics; D051379:Mice; D008809:Mice, Inbred C3H; D008819:Mice, Nude; D010957:Plasmids; D012190:Retroviridae / Q000235:genetics*; D015996:Survival Rate; D014161:Transduction, Genetic; D019076:Transgenes / Q000502:physiology; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000628:therapy*; D014779:Virus Replication
D000963:Antimetabolites; D049452:Green Fluorescent Proteins; D005437:Flucytosine; D043525:Cytosine Deaminase