Expression of steroidogenic enzymes necessary for <i>de novo</i> synthesis of androgens from cholesterol in LNCaP xenografts.

<p>(<b>A</b>) Enzymes and intermediates in the steroid bio-synthetic pathway leading from cholesterol to the formation of testosterone and DHT. LDLR and SR-B1 mediate cholesterol uptake; STAR and STARD3 mediate transport of cholesterol across the mitochondrial membrane where steroidogenesis is initiated. CYB5A is an important cofactor for the lyase activity of CYP17A. (<b>B</b>) Transcript profiling of tumors from all 4 treatment groups by qRT-PCR for the androgen receptor (AR), the androgen regulate gene PSA, and genes involved in cholesterol transport. (<b>C</b>) Transcript profiling for the expression of steroidogenic genes and the CYB5 cofactor. The mean cycle threshold (CT) for detection of each transcript was normalized to expression of the housekeeping gene RPL13A in the same sample (delta or dCT). (<b>D</b>) The correlation of serum cholesterol levels with transcript expression of CYP17A as measured by qRT-PCR. Correlation coefficients and p values from linear regression analysis.