Andrew J. Gunn, Presenter: Nothing to Disclose

Yukihiro Hama MD, Abstract Co-Author: Nothing to Disclose

Yasuteru Urano PhD, Abstract Co-Author: Nothing to Disclose

Yoshinori Koyama MD, Abstract Co-Author: Nothing to Disclose

Peter L. Choyke MD, Abstract Co-Author: Researcher, General Electric Company Researcher, Koninklijke Philips Electronics NV Researcher, Becton, Dickinson and Company Researcher, Siemens AG

Hisataka Kobayashi MD, PhD, Abstract Co-Author: Nothing to Disclose

Tumor-targeted optical imaging probes could improve the intraoperative detection of ovarian tumor metastases and guide their resection. While the glycoprotein avidin (Av) has been shown to be an effective tumor-targeting moiety to which optical fluorophores can be attached, its immunogenicity precludes its clinical use. Thus, the glycoprotein galactosyl serum albumin (GSA) was tested for its ability to act as an ovarian tumor-targeting moiety.

The green fluorophore Rhodamine Green (RhodG) was conjugated to Av, GSA, and bovine serum albumin (BSA). The human ovarian adenocarcinoma cell line SHIN3 was transfected with a red fluorescent protein (RFP) for sensitivity and specificity calculations. Each conjugate was analyzed for its ability to label SHIN3 cells by flow cytometry, fluorescence microscopy, and in vivo optical fluorescence imaging using tumor-bearing mice. In order to show that GSA-RhodG can label various subsets of ovarian adenocarcinoma, eight additional human ovarian adenocarcinoma cell lines were analyzed using similar procedures.

Cellular binding and uptake was more efficient using GSA-RhodG than with either Av-RhodG or BSA-RhodG. In vivo spectral fluorescence images demonstrated a higher tumor-associated fluorescence for mice injected with GSA-RhodG than for either Av-RhodG or BSA-RhodG. Using the transfected RFP as a marker for tumor cells, the sensitivity and specificity of GSA-RhodG for detecting ovarian tumor foci was 100% and 99%, respectively. In addition, GSA-RhodG was able to bind eight other human ovarian adenocarcinoma cell lines in vitro and label them for in vivo optical fluorescence imaging.

GSA is a superior targeting moiety to which a fluorophore can be attached in order to perform in vivo optical fluorescence imaging of a variety of ovarian adenocarcinomas with extremely high sensitivity and specificity.

The intraoperative use of a tumor-targeted optical fluorophore like GSA-RhodG could aid in tumor resection and improve clinical outcomes for women with late stage ovarian cancer.

Gunn, A, Hama, Y, Urano, Y, Koyama, Y, Choyke, P, Kobayashi, H, D-galactose Receptor-targeted Optical Imaging of Peritoneal Carcinomatosis of Ovarian Origin Using Galactosyl Serum Albumin-conjugated Rhodamine Green.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5006367.html