Spindle pole body component 25 regulates stemness of prostate cancer cells.

Spindle pole body component 25 (SPC25) is a component of NDC80 complex that controls spindle assembly checkpoint in the microtubule-binding domain of kinetochores. We recently showed that SPC25 is required for prostate cancer (PrC) cell proliferation and cell cycle progression, and here we investigated whether SPC25 may be a Cancer stem cell (CSC) marker in PrC. We found that the levels of SPC25 were higher in PrC samples than paired normal prostate tissue. The overall survival of PrC patients with high SPC25 was poorer than those with low SPC25. PrC cell lines were transduced with two vectors carrying a luciferase reporter and a mCherry fluorescent reporter under a cytomegalovirus promoter and a nuclear green fluorescent protein reporter under the control of a SPC25 promoter, respectively, to allow differentiating SPC25+ from SPC25- PrC cells by flow cytometry. Compared to SPC25- cells, SPC25+ cells formed significantly more tumor spheres in culture, appeared to be more resistant towards docetaxel-induced cell apoptosis, and generated larger tumors with higher frequency after serial adoptive transplantation. Thus, our data suggest that SPC25 may be highly expressed in the CSC-like cells in PrC and could be a promising target for effective treatment of PrC.