Implication of expression of Nanog in prostate cancer cells and their stem cells

Recent studies suggested that the prostate cancer may arise from prostate cancer stem cells that share some same characteristics with normal stem cells. The purpose of this study was to detect the differences of Nanog expression between PC3 prostate cancer cell line and its tumor stem cells, and the relationship was preliminarily examined between Nanog and prostate cancer and its tumor stem cells. By using magnetic active cell sorting (MACS), we isolated a population of CD44⁺/CD133⁺ prostate cancer cells that display stem cell characteristics from PC3 cell line. Immunohistochemistry revealed positive expressions of CD44, CD133 and α₂β₁-integin in the isolated cells. CCK-8 analysis showed that isolated cells had a strong proliferative ability. The formation of the cell spheres in serum-free medium and holoclones in serum-supplied medium showed that the cells were capable of self-renewing, indicating that the isolated cells were a population of cancer stem-like cells derived from PC3 cell line. Western blotting exhibited that the isolated cells had higher experession of Nanog, an embryonic stem marker, as compared with PC3 cells. Our study showed that Nanog might be helpful in sustaining the self-renewal and the undifferentiation of prostate cancer stem cells, and may serve as a marker for prostate cancer stem cells for isolation and identification.