Circulating tumor cells (CTC) are potential precursors of metastasis. They are also of use in diagnosing malignancy and for prognostic purposes. Our laboratory has previously isolated CTC from orthotopic nude mouse models of human prostate cancer cells where the PC-3 cancer cells express green fluorescent protein (GFP). It was found that only orthotopic tumors produced CTC and not subcutaneous tumors, which may explain why orthotopic tumors metastasize and subcutaneous tumors do not. However, in this previous study, CTC were observed only after culture. In the present study, using the GFP-expressing PC-3 orthotopic model and immunomagnetic beads coated with anti-EpCAM and anti-PSMA, GFP-expressing CTC were isolated within 15 minutes and were readily visualized by GFP fluorescence. The immunomagnetic-bead-captured GFP-expressing PC-3 CTC could be immediately placed in 3-dimensional sponge cell culture where they proliferated. The combination of GFP-expression and immunomagnetic beads is very powerful method to obtain CTC for either immediate analysis or for biological characterization in vivo or 3-dimensional culture.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4273. doi:10.1158/1538-7445.AM2011-4273