Dietary rice bran component γ-oryzanol inhibits tumor growth in tumor-bearing mice.
METHODS
We investigated the effects of rice bran and components on tumor growth in mice.


RESULTS
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.


CONCLUSIONS
Induction of NK activity, activation of macrophages, and inhibition of angiogenesis seem to contribute to the inhibitory mechanism of tumor regression by γ-oryzanol.
Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea.
Sung Phil
SP
Kim
Mi Young
MY
Kang
Seok Hyun
SH
Nam
Mendel
M
Friedman
D020533:Angiogenesis Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000009:adverse effects / Q000627:therapeutic use*; D003110:Colonic Neoplasms / Q000178:diet therapy* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D003373:Coumaric Acids / Q000009:adverse effects / Q000627:therapeutic use; D003602:Cytotoxicity, Immunologic; D019587:Dietary Supplements; D005260:Female; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D055611:Natural Killer T-Cells / Q000276:immunology / Q000378:metabolism; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000517:prevention & control; D012275:Oryza / Q000737:chemistry*; D010666:Phenylpropionates / Q000009:adverse effects / Q000627:therapeutic use; D010936:Plant Extracts / Q000009:adverse effects / Q000627:therapeutic use*; D011897:Random Allocation; D012639:Seeds / Q000737:chemistry*; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000276:immunology / Q000473:pathology; D047368:Tumor Burden
D020533:Angiogenesis Inhibitors; D000972:Antineoplastic Agents, Phytogenic; D003373:Coumaric Acids; D010666:Phenylpropionates; D010936:Plant Extracts; C540967:cycloartenyl ferulate; C013172:gamma-oryzanol