Comparative chemosensitivity of circulating human prostate cancer cells and primary cancer cells.

The chemosensitivity of circulating PC-3 human prostate cancer cells, isolated from nude mice orthotopically implanted with PC-3, was compared to that of the parental PC-3 cells. PC-3 and circulating PC-3, both labeled with green fluorescent protein (GFP), were seeded in 96-well plates. The MTT assay was then performed at 24, 48, and 72 hours, comparing control cultures to cultures treated with cisplatin at 1, 2.5, 5 and 10 μm/ml, and docetaxel at 10, 20, 25 and 50 μm/ml at each time point. The circulating tumor cells (CTCs) exhibited a significantly increased sensitivity to both cisplatin and docetaxel when compared to PC-3 parental cells, with docetaxel having the greater efficacy. The future goal, based on these studies, is the culture of CTCs from cancer patients' peripheral blood for chemosensitivity testing, for improved individualized therapy.