The effect of normoxia and hypoxia on a prostate (PC-3) CD44/CD41 cell side fraction.

It has been reported that human prostate-derived PC-3 cells that are CD44- and CD 41 (a2 B1)-positive are enriched in cancer stem cells. This study compared the effect of PC-3 cell proliferation under normoxia or hypoxia on the initial and subsequent expression of this doubly-labeled side-fraction. Despite the numerical advantage of attached normoxic cells, 48 h of culture under nitrogen, an environment containing minimal oxygen and CO(2) resulting in an elevated pH of the medium, was associated with a higher percentage, absolute and relative number of doubly-labeled (DL) hypoxic compared to normoxic cells. At 24 h, the reverse was found. When the pH was controlled with the use of 95% nitrogen and 5% carbon dioxide, the percentage and number of normoxic DL cells exceeded hypoxic ones at both 24 and 48 h. At 24 h, 2-deoxy-L-glucose or sodium arsenate reduced normoxic DL cell numbers more than hypoxic ones. The interplay between hypoxia, increased medium pH and the effect of inhibitors as they might influence therapy are considered.