Effects of Siltuximab on the IL6 Induced Signaling Pathway in Ovarian Cancer

Sarcoma Biology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, MA 02114, USA.
Clinical Cancer Research (Impact Factor: 8.72). 12/2010; 16(6). DOI: 10.1158/1078-0432.CCR-10-1095
Source: PubMed


To explore potential therapeutic strategies for interrupting the interleukin-6 (IL-6) signaling pathway, we measured IL-6 expression in ovarian cancer tissues, and evaluated the effects of a monoclonal anti-IL-6 antibody; siltuximab (CNTO 328), on levels of IL-6-induced Stat3 phosphorylation, Stat3 nuclear translocation, and Stat3 downstream antiapoptotic genes. We then looked for enhancing paclitaxel sensitivity in multidrug-resistant ovarian cancer cell lines.
Expressions of IL-6 in ovarian cancer patient specimens were assessed by immunohistochemistry. Effects of siltuximab on IL-6-induced activation of Stat3 in an ovarian cancer cell line were determined by Western blot and real-time analysis of Stat3 nucleocytoplasmic translocation. Influence of combination of siltuximab and paclitaxel on tumor growth was evaluated in a xenograft mouse mode in vivo.
Metastatic and drug-resistant recurrent tumors have significantly higher IL-6 expression when compared with the matched primary tumors. Siltuximab specifically suppressed IL-6-induced Stat3 phosphorylation and Stat3 nuclear translocation. Treatment with siltuximab significantly decreased the levels of Stat3 downstream proteins such as MCL-1, Bcl-X(L), and survivin. Treatment with siltuximab reduced expression of multiple IL-6-induced genes in these cell lines. Furthermore, siltuximab increased the cytotoxic effects of paclitaxel in a paclitaxel resistant ovarian cancer cell line in vitro, but combination therapy with siltuximab did not have a significant effect on paclitaxel resistant tumor growth in vivo.
These results show that siltuximab effectively block the IL-6 signaling pathways and IL-6-induced gene expression. Blockage of IL-6 signaling may provide benefits for the treatment of ovarian cancer.

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Available from: Michiro Susa
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    • "In patients with advanced disease, high plasma levels of IL6 correlate with poor prognosis [11] and elevated levels are also present in malignant ascites [12]. Treatment of EOC cells with the anti-IL6 antibody (Ab) siltuximab has been shown to reduce constitutive cyto/chemokine production and inhibit IL6 signaling, tumor growth, the tumor-associated macrophage infiltrate, and angiogenesis in IL6–producing intraperitoneal ovarian cancer xenografts [13]. IL6 stimulates inflammatory cytokine production, tumor angiogenesis and the tumor macrophage infiltrate in ovarian cancer and these actions can also be inhibited by a neutralizing anti-IL6 Ab in clinical studies [14]. "
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    ABSTRACT: Epithelial ovarian cancer (EOC) is one of the most lethal gynecological cancers; the majority of EOC is the serous histotype and diagnosed at advanced stage. IL6 is the cytokine that has been found most frequently associated with carcinogenesis and progression of serous EOCs. IL6 is a growth-promoting and anti-apoptotic factor, and high plasma levels of IL6 in advanced stage EOCs correlate with poor prognosis. The objective of the present study was to identify IL6 co-regulated genes and gene network/s in EOCs. We applied bioinformatics tools on 7 publicly available data sets containing the gene expression profiles of 1262 EOC samples. By Pearson's correlation analysis we identified, in EOCs, an IL6-correlated gene signature containing 40 genes mainly associated with proliferation. 33 of 40 genes were also significantly correlated in low malignant potential (LMP) EOCs, while 7 genes, named C5AR1, FPR1, G0S2, IL8, KLF2, MMP19, and THBD were IL6-correlated only in advanced stage EOCs. Among the 40-gene signature EGFR ligand HBEGF, genes of the EGR family members and genes encoding for negative feedback regulators of growth factor signaling were included. The results obtained by Gene Set Enrichment and Ingenuity Pathway Analyses enabled the identification, respectively, of gene sets associated with 'early growth factor response' for the 40-gene signature, and a biological network related to 'thrombosis and cardiovascular disease' for the 7-gene signature. In agreement with these results, selected genes from the identified signatures were validated in vitro by real time RT-PCR in serous EOC cell lines upon stimulation with EGF. Serous EOCs, independently of their aggressiveness, co-regulate IL6 expression together with that of genes associated to growth factor signaling, arguing for the hypothesis that common mechanism/s driven by EGFR ligands characterize both advanced-stage and LMP EOCs. Only advanced-stage EOCs appeared to be characterized by a scenario that involves genes which are so far associated with thrombosis and cardiovascular disease, thus suggesting that this pathway is implicated in the growth and/or spread of more aggressive tumors. We have discovered novel activated signaling pathways that drive the expression of IL6 and of co-regulated genes and are possibly involved in the pathobiology of EOCs.
    Full-text · Article · Jul 2013 · BMC Genomics
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    • "Based on the detrimental consequences of IL-6 activity in ovarian cancer including induction of chemoresistance and malignant ascites formation, targeting IL-6 and its receptor system is considered as an emerging therapeutic approach for cancer chemotherapy. The promising results obtained from pre-clinical and clinical studies evaluating anti-IL-6 antibodies in recurrent chemotherapy-resistant ovarian cancer are a strong supportive proof for this claim [3], [41]. In addition, while immunologic responses have been a draw-back in some of the studies using anti-IL-6 monoclonal antibodies [42], minocycline as a non-biologic agent is not expected to cause such responses. "
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    ABSTRACT: Interleukin (IL)-6 has been shown to be a major contributing factor in growth and progression of ovarian cancer. The cytokine exerts pro-tumorigenic activity through activation of several signaling pathways in particular signal transducer and activator of transcription (STAT3) and extracellular signal-regulated kinase (ERK)1/2. Hence, targeting IL-6 is becoming increasingly attractive as a treatment option in ovarian cancer. Here, we investigated the effects of minocycline on IL-6 and its signaling pathways in ovarian cancer. In vitro, minocycline was found to significantly suppress both constitutive and IL-1β or 4-hydroxyestradiol (4-OH-E2)-stimulated IL-6 expression in human ovarian cancer cells; OVCAR-3, SKOV-3 and CAOV-3. Moreover, minocycline down-regulated two major components of IL-6 receptor system (IL-6Rα and gp130) and blocked the activation of STAT3 and ERK1/2 pathways leading to suppression of the downstream product MCL-1. In female nude mice bearing intraperitoneal OVCAR-3 tumors, acute administration (4 and 24 h) of minocycline (30 mg/kg) led to suppression of IL-6. Even single dose of minocycline was effective at significantly lowering plasma and tumor IL-6 levels. In line with this, tumoral expression of p-STAT3, p-ERK1/2 and MCL-1 were decreased in minocycline-treated mice. Evaluation of the functional implication of minocycline on metastatic activity revealed the capacity of minocycline to inhibit cellular migration, invasion and adhesion associated with down-regulation of matrix metalloproteinases (MMP)-2 and 9. Thus, the data suggest a potential role for minocycline in suppressing IL-6 expression and activity. These effects may prove to be an important attribute to the upcoming clinical trials of minocycline in ovarian cancer.
    Full-text · Article · Apr 2013 · PLoS ONE
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    • "One such anti-IL-6 monoclonal antibody is Siltuximab (CNTO 328). The safety and efficacy of Situximab has been demonstrated in preclinical studies and phase I/II clinical trials of diverse human pathologies and malignancies including Castleman's disease (van Rhee et al., 2010), multiple myeloma (Hunsucker et al., 2011; Voorhees et al., 2007), prostate cancer (Cavarretta et al., 2007; Cavarretta et al., 2008; Dorff et al., 2010; Karkera et al., 2011), renal cell carcinoma (Puchalski et al., 2010; Rossi et al., 2010), non-small cell lung cancer (Song et al., 2010), and ovarian cancer (Guo et al., 2010). Furthermore, IL-6R can be targeted with tocilizumab, an anti-IL-6R monoclonal antibody that has shown promising results in IL-6- driven autoimmune diseases (Tanaka et al., 2011) and was recently approved by the FDA for the treatment of rheumatoid arthritis. "

    Full-text · Chapter · Dec 2011
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