Novel method to detect, isolate, and culture prostate culturing circulating tumor cells.

Background: Effectively detecting and culturing circulating tumor cells (CTCs), is critical for diagnosis of early metastasis, monitoring anti-cancer therapeutic efficacy, and drug screening. However, most current FDA approved CTC detection methods are based on antibody binding, which has limitations due to the nature of variations in antibody preparation and antibody-CTC size mismatches. Thus, searching for alternative and advanced methods is urgent and necessary. Methods: Prostate cancer tissue was digested by collagenase and cultured. Cancer stromal cells were identified and labelled with 4',6-diamidino-2-phenylindole (DAPI) before incubation with whole blood of cancer mice (bearing a later stage of prostate cancer). The attached blood CTCs on the DAPI-labeled cancer stromal cells were detected, isolated, cultured and produced into individual cancer cell lines. Results: Five clones of prostate cancer cells isolated from cancer tissue were successfully cultured. One (Clone-1) of the five clones showed positive staining for all three cancer stromal cell markers (CD133, alpha 2 beta 1 integrin and CD44). Clone-1 cells rich with epithelial cell adhesion molecule (EpCAM) on the cell surface were further identified. The Clone-1 stromal cells labeled as "bait" attracted and caught a trace number of CTCs from the whole blood of mice with advanced stage cancer. Efficient culturing of the caught CTCs from single cell to forming of individual cancer cell line(s) were established. Conclusions: We present a fundamental advancement of CTC detection and culturing using a different mechanism ( cell-cell interaction) rather than the traditional antibody-based immune-binding, such as CellSearch (TM) system. This study has potential to be fully developed into a novel approach for early cancer metastasis detection, and chemotherapy efficacy monitoring. The efficiently cultured CTCs could be used for single-clone CTC analysis and anti-cancer drug screening to further advance the development of individualized medicine.