Interleukin-6 differentially regulates androgen receptor transactivation via PI3K-Akt, STAT3, and MAPK, three distinct signal pathways in prostate cancer cells

The effects of IL-6 on prostate cancer cells are well documented yet remain controversial. Some reports suggested that IL-6 could promote prostate cancer cell growth, while others showed that IL-6 could repress prostate cancer cell growth. Here, we systemically examined various IL-6 signaling pathways in prostate cancer cells and found that IL-6 could go through at least three distinct pathways to modulate the functions of androgen receptor (AR), a key transcriptional factor to control the prostate cancer growth. Our results show that IL-6 can enhance AR transactivation via either the STAT3 or MAPK pathways. In contrast, IL-6 can suppress AR transactivation via the PI3K-Akt pathway. Co-existence of these various signaling pathways may result in either additive or conflicting effects on AR transactivation. Together, our results indicate that the balance of these various pathways may then determine the overall effect of IL-6 on AR transactivation. (C) 2003 Elsevier Science (USA). All rights reserved.