Enhanced androgen sensitivity in serum-free medium of a subline of the LNCaP human prostate cancer cell line

The LNCaP-Fast Growing Colony (FGC) human prostate cancer cell line proliferates in response to the addition of dihydrotestosterone (DHT) 10^-10-10^-8 M in charcoal-stripped serum-supplemented media. LNCaP-FGC cells will not attach or proliferate in serum-free conditions. LNCaP-FGC stock cultures were maintained in medium supplemented with 10% FBS and added DHT (10^-9 M) for > 25 passages (6 months). The resultant subline was designated as LNCaP-ss (supersensitive) because of its ability to attach in serum-free medium and to proliferate in response to very low levels of DHT. LNCaP-ss cells were grown in serum-free medium and proliferation assessed after 2, 3, 5, and 7 days' treatment with DHT. Significant enhancement of growth was demonstrated after 7 days' treatment with DHT over a wide range of concentrations (DHT 10^-15 - 10^-7 M) with maximal stimulation (3 × control, p < .001) noted with DHT 10^-14 M. Changing the medium during the course of the experiment decreased, but did not eliminate, the DHT-induced cellular proliferation. Scatchard analysis of binding studies with LNCaP-ss cells revealed that both the K_d for the androgen receptor (AR) and the number of AR sites/ cell were similar to the corresponding values reported for the parental line. AR mRNA levels in LNCaP-ss cells, as measured by RNase protection assay, were significantly down-regulated by 7 days' treatment with DHT 10^-15, 10^-13, and 10^-9 M. We conclude that maintaining LNCaP-FGC cells for 6 months in medium supplemented with DHT resulted in the development of a subline, LNCaP-ss, which can attach and proliferate in serum-free medium. This subline is sensitive to very low levels of androgen, as evidenced by increased proliferation and down-regulation of AR mRNA levels. (Steroids 58:439-444, 1993).