ANDROGENS MARKEDLY STIMULATE THE ACCUMULATION OF NEUTRAL LIPIDS IN THE HUMAN PROSTATIC ADENOCARCINOMA CELL-LINE LNCAP

Microscopic evaluation of LNCaP cells stained with the lipophilic dye Oil red O revealed that androgens induce a marked stimulation of lipid droplet accumulation. As determined by quantitative analysis of the O n red O extracted from the stained cells, stimulatory effects of the s ynthetic androgen R1881 became apparent at concentrations as low as 10 (-11) M. Maximal induction (15-fold) was reached at 10(-8) M. Increase s were observed 2 days after hormone addition and were maximal 1 day l ater. Accumulation of lipid droplets was also induced by mibolerone (a nother synthetic androgen) and by the natural androgens testosterone a nd dihydrotestosterone. In agreement with the aberrant ligand specific ity of the mutated androgen receptor in LNCaP cells, stimulation of li pid accumulation was also apparent after treatment with progesterone a nd estradiol. Cortisol and the synthetic glucocorticoid dexamethasone wore ineffective. The androgen antagonist Casodex (bicalutamide) aboli shed the stimulatory effect of R1881, further supporting the Involveme nt of the androgen receptor. In agreement with this conclusion, no cha nges in lipid accumulation were observed after androgen treatment of t he androgen receptor-negative prostate turner lines PC-3 and DU-145. T o investigate the nature of the lipids affected by androgens, lipid ex tracts were analyzed by TLC, complemented with enzymatic lipid analyse s. Androgens were shown to have major effects on the content of trigly cerides and cholesterol esters (33- and 7-fold stimulation, respective ly), the two main classes of lipids stained by Oil red O. Phospholipid and cholesterol contents were increased by a factor of 2. Incorporati on studies with [2-C-14]acetate revealed that androgens caused a major stimulation of 2-C-14 incorporation into triglycerides and cholestero l esters (11- and 13-fold, respectively), suggesting that androgens ac t at least in part at the level of lipid synthesis. Taken together, th ese findings indicate that androgens, besides affecting proliferation and protein secretion, also markedly stimulate the production and accu mulation of neutral lipids, revealing a novel interesting aspect of an drogen regulation of LNCaP cells.