Interleukin 6, a nuclear factor-κB target, predicts resistance to docetaxel in hormone-independent prostate cancer and nuclear factor-κB inhibition by PS-1145 enhances docetaxel antitumor activity

Josep Domingo-Domenech, Cristina Oliva, Ana Rovira, Jordi Codony-Servat, Marta Bosch, Xavier Filella, Clara Montagut, Marian Tapia, Clara Campás, Lenny Dang, Mark Rolfe, Jeffrey S. Ross, Pere Gascon, Joan Albanell, Begoña Mellado

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To investigate whether nuclear factor κB (NF-κB)/interleukin 6 (IL-6) was linked to docetaxel response in human prostate cancer cell lines, and whether inhibition of NF-κB sensitized tumor cells to docetaxel. We also aimed to correlate IL-6 (as a surrogate marker of NF-κB) and docetaxel response in hormone-independent prostate cancer (HIPC) patients. Experimental Design: Hormone-dependent (LNCaP) and hormone-independent (PC-3 and DU-145) prostate cancer cell lines were exposed to docetaxel alone or combined with the NF-κB inhibitor PS-1145 (an inhibitor of IκB kinase-2). Effects of dose, exposure time, and schedule dependence were assessed. Activation of NF-κB was assayed by electrophoresis mobility shift assay and luciferase reporter assay, IL-6 levels by ELISA, and cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay. Cell cycle and apoptosis were assessed by fluorescence-activated cell sorting analysis. Apoptosis was also measured by detection of cleavage of poly(ADP-ribose) polymerase. In patients with metastatic HIPC receiving docetaxel-based chemotherapy, IL-6 serum levels were assayed before chemotherapy and every 3 to 4 weeks thereafter. Results: PC-3 and DU-145 cells had higher NF-κB activity, secreted more IL-6, and were more resistant to docetaxel than LNCaP cells. NF-κB activity was induced by docetaxel. Cotreatment with docetaxel and PS-1145 prevented docetaxel-induced NF-κB activation, reduced IL-6 production, and increased docetaxel effects on cell viability in PC-3 and DU-145 cells but not in LNCaP. Synergism with docetaxel and PS-1145, as assayed by median-effect principle, was observed in DU-145 and PC-3. In HIPC patients, pretreatment IL-6 serum levels correlated to prostate-specific antigen (PSA) response: median IL-6 level was 10.8 ± 9.5 pg/mL in PSA responders versus 36.7 ± 20.8 pg/mL (P = 0.006) in nonresponders. A PSA response was also linked to a decline in IL-6 levels during treatment. Median overall survival was 6.8 months in patients with high IL-6 versus 16.6 months in those with low IL-6 (P = 0.0007). On multivariate analysis, pretreatment IL-6 (P = 0.05) was an independent prognostic factor for time to disease progression and survival. Conclusions: Inhibition of NF-κB emerges as an attractive strategy to enhance docetaxel response in prostate cancer. The interest of this view is further supported by a significant association between high IL-6 in sera of HIPC patients and decreased response to docetaxel.

Original languageEnglish (US)
Pages (from-to)5578-5586
Number of pages9
JournalClinical Cancer Research
Volume12
Issue number18
DOIs
StatePublished - Sep 15 2006

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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