A noninvasive reporter system to image adenoviral-mediated gene transfer to ovarian cancer xenografts

Objective. Gene therapy trials for ovarian cancer would benefit from a noni nvasive imaging modality to detect the location and extent of gene transfer . The human type 2 somatostatin receptor gene (hSSTr2) was evaluated as a r eporter gene for imaging adenoviral (Ad) gene transfer to ovarian cancer. Methods. A replication-incompetent Ad vector encoding hSSTr2 (Ad-hSSTr2) wa s used to infect SKOV3.ip1 cells in vitro and tumors growing in nude mice. Gamma camera imaging detected uptake of 99m-Tc-P2045 (a somatostatin analog ue) due to expressed hSSTr2. Results. Specific uptake of 99m-Te-P2045 was imaged in Ad-hSSTr2-infected c ells in vitro. Noninvasive in vivo imaging detected gene transfer to intrap eritoneal tumors. Uptake of 99m-TcP2045 (percentage dose per gram of tumor) averaged 2.2 and 0.18 for Ad-hSSTr2-injected mice and controls, respective ly. Conclusion. This study reports the first noninvasive imaging method for ima ging gene transfer to ovarian cancer. A human gene therapy trial is planned . (C) 2001 Academic Press.