Figure 4. LnCaP C81 cells have elevated cholesterol synthesis.

4A. We examined cholesterol synthesis in C33 and C81 cell cultures via LC/MS isotopomer analysis after incorporation of ¹³C-acetate. The sum of the areas of ¹³C-labeled-isotopomers with m/z of 371.4-399.4 co-eluting with the cholesterol peak, divided by the total amount of cholesterol isotopomers, was used as a measure of cholesterol synthesis. C81 cell lysates showed a 52% increase in newly synthesized cholesterol compared to C33 cells. 4B. Fluidigm RT-PCR analysis of C81 transcripts relative to C33 revealed elevated expression of several enzymes involved in cholesterol synthesis and mobilization of cholesterol to mitochondria. Those genes with an asterix* are established SXR target genes.