Anthony Razzak

Metabolism/nutritionLipopolysaccharide-Stimulated RAW 264.7 Macrophage Inducible Nitric Oxide Synthase and Nitric Oxide Production Is Decreased by an Omega-3 Fatty Acid Lipid Emulsion

BACKGROUND Omega-3 fatty acids (omega-3 FA) have been demonstrated to have anti-inflammatory properties, postulated to occur through several principal mechanisms, including (1) displacement of arachidonic acid from the cellular membrane; (2) shifting of prostaglandin E(2) and leukotriene B(4) production; and (3) molecular level alterations including decreased activation of nuclear factor kappa B and activator protein-1. An additional regulator that is likely associated is the production of nitric oxide (NO) by nitric oxide synthetase. NO is a short-lived free radical involved in many biological functions. However, excessive NO production can lead to complications, suggesting that decreased NO production is a potential target for some inflammatory diseases. We hypothesized that pretreating with an omega-3 FA lipid emulsion would decrease the production of NO in macrophages and that this effect would occur through alterations in inducible nitric oxide synthetase (iNOS). MATERIALS AND METHODS Greiss reagent was used to assess NO production in RAW 264.7 macrophages following omega-3 or omega-6 FA treatment alone or in combination with lipopolysaccharide (LPS) stimulation for 12 h/24 h. iNOS levels were determined by Western blot. Tumor necrosis factor-alpha levels were determined by enzyme-linked immunosorbent assay. RESULTS Following LPS-stimulation, omega-3 FA pretreatment at 12 and 24 h produced significantly less NO (P < 0.05) compared to omega-6 FA or media-only conditions. omega-3 FA pretreatment at 12 and 24 h also had less iNOS protein expression compared to omega-6 FA or media-only conditions. Tumor necrosis factor-alpha production was significantly decreased with omega-3 FA treatment compared to omega-6 FA treatment (P < 0.05) after 24 h LPS stimulation. CONCLUSION These experiments demonstrate that, in addition to other anti-inflammatory effects, omega-3 FA lipid emulsions also significantly lower NO production in LPS-stimulated macrophages through altered iNOS protein expression.

Feasibility evaluation of emodin (rhubarb extract) as an inhibitor of pancreatic cancer cell proliferation in vitro.

Emodin is a commonly used traditional herbal treatment in China, including use for pancreatic malignancy. In this study, the potential for emodin to inhibit pancreatic cancer cell proliferation was examined using 4 human pancreatic adenocarcinoma cell lines: Mia Paca-2, BxPC-3, Panc-1, and L3.6pl. WST-1 proliferation, propidium iodide flow cytometry cell cycle analysis, and poly-ADP-ribose polymerase (PARP) Western blot analysis were performed. Forty-eight-hour treatment with 50 muM emodin inhibited proliferation in Mia Paca-2 cells by 42%, BxPc-3 by 38%, L3.6pl by 56%, and Panc-1 by 18% (all P < .01). In three-fourths of the cell lines, emodin treatment resulted in an increase (from 4.7% to 22%) in the cell population number in apoptosis when measured by flow cytometric analysis. Mia Paca-2 revealed a significant PARP cleavage product when compared with control. These feasibility experiments provide initial evidence that emodin exerts an antiproliferative effect, likely through apoptosis induction-related mechanism(s), that is reproducible in various human pancreatic cancer cell lines.

Omega-3 fatty acids: investigations from cytokine regulation to pancreatic cancer gene suppression.

Omega-3 (omega-3) fatty acids have been clinically and experimentally associated with the amelioration of chronic and acute inflammation; however, the mechanisms for these observations have not been well defined. During the past decade, laboratories of nutrition and inflammation have demonstrated that the anti-inflammatory activities of omega-3 fatty acids occur at least in part through the inhibition of macrophage-elaborated tumor necrosis factor production and through inactivation of the nuclear factor-kappaB signaling pathway subsequently altering proinflammatory cytokine transcription. These observations led to further experiments that support a role for omega-3 fatty acids in the restoration of apoptosis in various chemoresistant tumor models through a similar inactivation of the nuclear factor-kappaB signaling pathway. The potential for nutritional modulation of host inflammation has been an ongoing and expanding area of investigation. An increased emphasis has been placed on the potential for diet and dietary supplements to serve as modulators of host response to disease, injury, and infection.