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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: METHODS, RESULTS. Meshes: Angiogenesis Inhibitors, Animals, Antineoplastic Agents, Phytogenic, Colonic Neoplasms, Coumaric Acids, Cytotoxicity, Immunologic, Dietary Supplements, Female, Macrophages, Peritoneal, Mice, Mice, Inbred BALB C, Natural Killer T-Cells, Neoplasm Transplantation, Neovascularization, Pathologic, Oryza, Phenylpropionates, Plant Extracts, Random Allocation, Seeds, Specific Pathogen-Free Organisms, Spleen, Tumor Burden.
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Does dietary rice bran component γ-oryzanol inhibit tumor growth in tumor-bearing mice? Context: We investigated the effects of rice bran and components on tumor growth in mice. Mice fed standard diets supplemented with rice bran, γ-oryzanol, Ricetrienol®, ferulic acid, or phytic acid for 2 weeks were inoculated with CT-26 colon cancer cells and fed the same diet for two additional weeks. Tumor mass was significantly lower in the γ-oryzanol and less so in the phytic acid group. Tumor inhibition was associated with the following biomarkers: increases in cytolytic activity of splenic natural killer (NK) cells; partial restoration of nitric oxide production and phagocytosis in peritoneal macrophages increases in released the pro-inflammatory cytokines tumor necrosis factor-α, IL-1β, and IL-6 from macrophages; and reductions in the number of blood vessels inside the tumor. Pro-angiogenic biomarkers vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), and 5-lipoxygenase-5 (5-LOX) were also significantly reduced in mRNA and protein expression by tumor genes. ELISA of tumor cells confirmed reduced expression of COX-2 and 5-LOX up to 30%. Reduced COX-2 and 5-LOX expression downregulated VEGF and inhibited neoangiogenesis inside the tumors.
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Induction of NK activity, activation of macrophages, and inhibition of angiogenesis seem to contribute to the inhibitory mechanism of tumor regression by γ-oryzanol. Final Decision: yes