Abstract #494: Anti-inflammatory effects of the nigella sativa seed extract, thymoquinone, in pancreatic cancer cells

Background: Both hereditary and sporadic forms of chronic pancreatitis are associated with an increased risk of developing pancreatic ductal adenocarcinoma (PDA). Inflammation has been identified as a significant factor in the development of solid tumor malignancies. Thymoquinone (Tq), the major constituent of the Nigella sativa oil extract induces apoptosis and inhibits PDA cell proliferation. Tq also increases p21 WAF1 expression, inhibits histone deacetylase (HDAC) activity, and induces histone hyperacetylation. HDAC inhibitors have been shown to ameliorate inflammation-associated cancer in several animal models. Objective: To evaluate the anti-inflammatory potential of Tq in PDA cells in comparison to a specific HDAC inhibitor, trichostatin A (TSA). Methods: PDA cells (AsPC-1, HS766T, MiaPaca) were cultured and treated with or without Tq (25-75 \#956;M), with or without pre-treatment of TNF-\#945; (30nM). The effect of Tq on the expression of different proinflammatory cytokines and chemokines was analyzed by real time PCR. Luciferase-labeled promoter studies evaluated the effect of Tq on the transcription of monocyte chemoattractant protein-1 (MCP-1) and nuclear factor-\#954;B (NF-\#954;B). The effect of Tq on the endogenous and TNF-\#945;-induced activation and nuclear translocation of NF-\#954;B was examined by ELISA and immunohistochemistry. Results: Within 6 h, Tq significantly and dose-dependently reduced PDA cell production of TNF-\#945; (p<0.02), interleukin (IL-1\#946;) (p<0.02), IL-8 (p<0.05), Cox-2 (p<0.002), and MCP-1 (p<0.005). There was no reduction in interferon-\#947; (IFN-\#947;) in the same cultures. Within the same time period, TSA reduced the production of Cox-2 (p<0.02) and MCP-1 (p<0.05), but had no effect on TNF-\#945;, IL-8, or IL-1\#946;. Tq, but not TSA, significantly and dose-dependently reduced the intrinsic activity of the MCP-1 promoter. Tq also inhibited the intrinsic and the TNF-\#945;-mediated activation of NF-\#954;B in PDA cells and reduced the transport of NF-\#954;B from the cytosol to the nucleus. Conclusions: Our data demonstrate previously undescribed anti-inflammatory activities of Tq in PDA cells, which are paralleled by inhibition of NF-\#954;B. Tq as a novel inhibitor of proinflammatory pathways provides a promising strategy that combines anti-inflammatory and proapoptotic modes of action.

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 494.