Comparative$C_{19}-Radiosteroid$Metabolism by MA 160 and HeLa Cell Lines

Since the designation of the human MA 160 line as prostatic epithelial cells has been questioned and the possibility of HeLa cross contamination raised, this comparative study of$C_{19}-radiosteroid$transformation in MA 160 and HeLa monolayer cultures was done to determine whether these cells possess the distinguishing features of reductive and oxidative androgen metabolism expected in male and female genital organs, respectively. We compared the radiometabolite patterns produced by incubating$[^{14}C] testosterone$(300 nM) and$[^{3}H] testosterone$(3 nM) and$5\alpha-dihydrotestosterone$($17\beta-hydroxy-5\alpha-androstan-3-one$) with cultures of prostatic MA 160 and HeLa Parent, TCRC-1, TCRC-2 and ATC 229 cells.$C_{19}-Radiosteroid$metabolite patterns from MA 160 cell incubations also were compared with patterns generated by MA 196 fibroblasts from abdominal skin of the same donor. MA 160 cells metabolized radiotestosterone predominantly to$5\alpha-dihydrotestosterone$,$5\alpha-androstane-3\alpha,17\beta-diol$and$5\alpha-androstane-3\beta,17\beta-diol$. The diol epimers were the principal metabolites of$5\alpha-dihydrotestosterone$radiosubstrate. In contrast, radiotestosterone metabolism by MA 196 and HeLa Parent, TCRC-1 and TCRC-2 cells was overwhelmingly to the 17-oxosteroids 4-androstene-3,17-dione and androsterone. Another pathway was operative in HeLa 229 and, to a minor extent, in TCRC-1, which converted radiotestosterone to$4-androstene-3\alpha,17\beta-diol$and$5\alpha-androstane-3\alpha,17\beta-diol$, with little formation of$5\alpha-dihydrotestosterone$. MA 160 cells thus metabolize radiotestosterone preponderantly to$5\alpha-reduced 17\beta-hydroxysteroids$as expected for prostatic epithelial cells, whereas HeLa cells show heterogeneity in metabolizing the labeled hormone by the alternative 17-oxosteroid and$\Delta^4-androstenediol$pathways.