Prostate Cancer Research Today is a free monthly online journal that collates and summarizes the latest research about Prostate Cancer, including details on symptoms, genetics, screening, treatment, information.

The antiapoptotic effect of IL-6 autocrine loop in a cellular model of advanced prostate cancer is mediated by Mcl-1.

Cavarretta IT, Neuwirt H, Untergasser G, Moser PL, Zaki MH, Steiner H, Rumpold H, Fuchs D, Hobisch A, Nemeth JA, Culig Z

Department of Urology, Innsbruck Medical University, Innsbruck, Austria.

Levels of the proinflammatory cytokine interleukin-6 (IL-6) are increased in therapy-resistant prostate cancer. IL-6 has been considered a positive growth factor in late-stage prostate cancer cells and a potential target for therapeutic interference. Effects of inhibition of IL-6 on cell survival were studied in LNCaP-IL6+ cells, a model system for advanced prostate cancer, which produce IL-6. We show that the autocrine IL-6 loop is responsible for resistance to apoptosis and increased cellular levels of myeloid cell leukemia-1 (Mcl-1) protein, an antiapoptotic member of the Bcl-2 family. Treatment of cells with a chimeric anti-IL-6 antibody (CNTO 328) led to the induction of apoptosis and downregulation of Mcl-1 protein levels. Specific knockdown of Mcl-1 gene expression by small interfering RNA also yielded an increase in apoptosis of LNCaP-IL-6+ cells. Vice versa, inactivation of IL-6 autocrine loop had no influence on apoptosis levels in the absence of Mcl-1, thus suggesting this molecule as a mediator of the survival action of IL-6. Mcl-1 protein regulation by the endogenous cytokine directly involved the extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway. Our data support the concept of anti-IL-6 targeted therapy in therapy-resistant prostate cancer.

Published 3 May 2007 in Oncogene, 26(20): 2822-32.
Full-text of this article is available online (may require subscription).

© 2004-2008 Prostate Cancer Research Today. All Rights Reserved.