The objective of this study was to investigate the activation of natural killer (NK) cells and anticancer effects of exo-biopolymer from rice bran cultured with Lentinus edodes [rice bran exo-biopolymer (RBEP)]. Oral administration of RBEP induced the activation of NK cells in a dose-dependent manner. RBEP also prolonged the life spans of mice transplanted with Sarcoma-180 cells and inhibited growing Sarcoma-180 cells in intraperitoneum. Solid tumor growth was also suppressed by oral administration of RBEP in C57/Bl6 mice transplanted with B16/Bl6 melanoma. Intraperitoneal injection of RBEP was more effective than oral administration at the same dosage in mice with transplanted tumor cells. According to this result, when RBEP directly contacts immune cells, the anticancer activity is higher than by indirectly inducing an immune response through oral administration. Therefore, we suggest that the administration of RBEP may be effective for preventing and/or treating cancer through NK cell activation. However, further studies are needed to elucidate the possible mechanisms of the anticancer activity and to investigate the other beneficial effects of RBEP for the development of a new biological response modifier.
Panax ginseng Meyer has been used for the treatment of immune diseases and for strengthening the immune function. In this study, we evaluated the innate immune-stimulating functions and action mechanisms of white ginseng (WG) and heat-processed ginseng (HPG) in RAW264.7 cells. According to LC-MS analysis results, WG contained typical ginsenosides, such as Rb1, Rc, Rb2, Rd, and Rg1, whereas HPG contained Rg3, Rk1, and Rg5 as well as typical ginsenosides. HPG, not WG, enhanced NF-κB transcriptional activity, cytokine production (IL-6 and TNF-α), and MHC class I and II expression in RAW264.7 cells. In addition, HPG phosphorylated MAPKs and NF-kB pathways. In experiments with inhibitors, the ERK inhibitor completely suppressed the effect of HPG on IL-6 and TNF-α production. HPG-induced c-Jun activation was suppressed by an ERK inhibitor and partially suppressed by JNK, p38, and IκBα inhibitors. Collectively, these results suggested that HPG containing Rg3, Rg5, and Rk1 increased macrophage activation which was regulated by the ERK/c-Jun pathway in RAW264.7 cells.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.