Targeting RAGE Expression in Human Ovarian Cancer

Receptor for Advanced Glycation Endproducts (RAGE) is expressed in ovarian tissue and associated with ovarian carcinoma. With a radiolabeled anti-RAGE antibody, we proposed to show extent of RAGE expression in animal model and effect of blocking RAGE on ovarian cancer cell growth. Methods: We measured inhibition of p-Akt and p-stat3 in SKOV-3 human ovarian carcinoma cell line and measured cell growth suppression in culture. For imaging, female nude mice (n = 15) at 6 wks of age were injected with luciferase expressing human ovarian cancer cells into the right flank. Four-five weeks later, animals were injected with luciferin and imaged on optical imager followed by injection with 111In-anti-RAGE F(ab’)2 (n = 7) or 111In-control IgG F(ab’)2 and 48 h later, were imaged on micro-SPECT/CT. Focal tracer uptake on scans was quantified, the tumors removed, radioactivity counted, and sectioned for histological and immunohistochemical examination. Results: RAGE antibody pretreatment inhibited p-stat3 and p-AKT expression in SKOV-3 cells and there was a dose related reduction in cell growth in culture. There was good co-localization of the luciferase producing tumor on the optical scan and tumor location at necropsy with the focal uptake of the 111In-anti-RAGE F(ab’)2. Quantitative tracer uptake in the tumor from scans showed that uptake of 111In-anti-RAGE F(ab’)2 as %ID was 2.4 fold higher than 111In-control F(ab’)2 (P = 0.01) confirmed by gamma well counting. Dual immunofluorescent staining for RAGE and PAX8 in tumors showed high expression of RAGE and co-localization with PAX8 positive stained cells. Conclusion: RAGE expression in ovarian tumors in live animals can be imaged and quantified. An anti-RAGE F(ab’)2 used for imaging shows blocking properties and suppresses ovarian cancer cell growth.