Human prostate cancer initiating cells isolated directly from localized cancer do not form prostaspheres in primary culture

BACKGROUND Recent experimental studies suggest that hierarchical expansion from a minor population of cancer cells with an unlimited self-renewal capacity, termed cancer initiating cells (CICs), drives both lethality and heterogeneity of prostate cancer. Human prostate CICs have been established from only two primary prostate cancer patients, with the remaining established CIC lines being derived from metastatic sites from <10 patients. This suggests that the established CIC lines are significant outliers and may not be representative of the prostate CICs seen clinically. Thus, there is an urgent need to develop new approaches to achieve the routine establishment of CIC containing lines, particularly derived from primary prostate cancers. METHODS In the present studies, we confirmed that in serum free, high Ca2+ (i.e., DMEN: F12) growth factor defined (GFD) media plus androgen, a large (n?=?10) series of established human prostate cancer cell lines derived from both localized and metastatic sites characteristically self-associate in suspension and grow as unattached spheroids, termed prostaspheres which contain CICs based upon their self-renewal in vitro and tumorigenicity in vivo. RESULTS Unfortunately, however, while dissociated single cells from human primary prostate cancer tissues are viable, contain CICs as documented by their ability to take and proliferate as xenografts, and produce prostaspheres when plated with serum free, high Ca2+/GFD-media plus androgen onto standard tissue culture flask, these prostasphere do not contain CICs. CONCLUSION The development of reproducibly methods to culture CICs isolated directly from localized cancers is still an urgent unmeet need of the prostate cancer research community. Prostate 72:14781489, 2012. (c) 2012 Wiley Periodicals, Inc.