Abstract 296: Characterization of prostate cancer circulating tumor cells using E-selectin coated-microtubes

Abstract

Abstract Background: Metastasis and invasion is facilitated by adhesion of circulating tumor cells (CTCs) to endothelial cells in the blood vessel. Initial recruitment of CTCs to the blood vessel endothelium is mediated through selectin proteins. We used microtube coated with selectin proteins to simulate CTC adhesion under flow, to elucidate the complex physicochemical dynamics that control CTC adhesion in the bloodstream. Methods: Sterilized microrenathane microtubes were functionalized by E-selectin +/- anti-PSMA (mAb J591) and anti-EpCAM antibodies. Functionalized microtubes were used to observe the rolling behavior of prostate cancer cell lines MDAPCa2b, LNCaP C4-2, and PC-3. MDAPCa2b cells alone or mixed with normal peripheral blood mononuclear cells (PBMCs) were incubated with fluorescently conjugated mAbJ591, and the mixture flowed through the microtube for identification and capture efficiency. PBMCs isolated from prostate cancer patient's blood were similarly processed. Results: MDAPCa2b cells showed robust rolling at 1 dyne/cm2 shear stress while LNCaP, C4-2, and PC-3 cells did not exhibit rolling behavior on E-selectin coated microtubes. 7.5 cells were observed rolling at 1 dyne/cm2 compared to 1.5 cells at 8 dyne/cm2 per 100 mm2 area. To determine if prostate cancer cells could be identified in a mixture of PBMCs, MDAPCa2b cells were spiked in PBMCs and labeled with fluorescently conjugated mAb J591. MDAPCa2b cells demonstrated selective fluorescence which did not alter their rolling behavior. A 50% capture efficiency of MDAPCa2b cells spiked in PBMCs was achieved when flowed through E-selectin and anti-PSMA coated microtube. After establishing rolling and selective fluorescence in prostate cancer cell line, we used prostate cancer patient's blood. CTCs in prostate cancer patient's blood showed rolling behavior on E-selectin coated microtube. Further, these CTCs were PSMA-positive after incubation with fluorescently conjugated mAbJ591 and easily identified during the flow through the microtube. Conclusion: Our data shows that CTCs in prostate cancer patients exhibit rolling behavior, which may facilitate invasion and metastasis. Further, selective ex vivo labeling of CTCs enables rapid identification for subsequent characterization of their adhesion and invasive phenotype. 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 296. doi:10.1158/1538-7445.AM2011-296