Sakaguchi Kaito, Zhong Ming, Kawai Saeko, Shimizu Yoshio, Gohda Eiichi
1 Okayama University, Okayama, Japan.
2 Bizen Chemical Co, Ltd, Akaiwa City, Okayama, Japan.
Integr Cancer Ther. 2018 Mar;17(1):31-40. doi: 10.1177/1534735416681640. Epub 2016 Dec 5.
A reduced number and/or reduced activity of natural killer (NK) cells, which are important for defense against a variety of cancers and viral infections, occur under various stress conditions and in patients with various diseases. In this article, we report that the 30% to 50% ethanol precipitate of oyster extract (EPOE50) dose-dependently enhanced the activity of mouse spleen NK cells in vitro and in vivo. The activity of EPOE50 was eluted with a molecular weight of about 2000 by gel filtration and was inactivated by periodate but not by proteinase K. The activity of highly purified NK cells was also augmented by EPOE50 but not by oligodeoxyribonucleotide 1585, which mimics bacterial DNA. Administration of EPOE50 to mice stimulated splenic NK cell activity without a change in splenic NK cell populations. Although the proliferation of B16 tumor cells in vitro was slightly stimulated by EPOE50, the growth of B16 melanoma in vivo was dose-dependently suppressed by administration of EPOE50. Taken together, our results indicate that EPOE50 augmented NK cell activity and that its administration to mice inhibited tumor growth presumably through the activation of NK cells and also suggest that the active substance is a sugar-containing oligomer or polymer and is not of bacterial origin.
自然杀伤（NK）细胞数量减少和/或活性降低在各种应激条件下以及患有各种疾病的患者中都会出现，而NK细胞对抵御多种癌症和病毒感染至关重要。在本文中，我们报告牡蛎提取物的30%至50%乙醇沉淀物（EPOE50）在体外和体内均剂量依赖性地增强了小鼠脾脏NK细胞的活性。EPOE50的活性通过凝胶过滤以约2000的分子量洗脱，并且被高碘酸盐灭活，但不被蛋白酶K灭活。高度纯化的NK细胞的活性也被EPOE50增强，但不被模拟细菌DNA的寡脱氧核糖核苷酸1585增强。给小鼠施用EPOE50可刺激脾脏NK细胞活性，而脾脏NK细胞群体没有变化。尽管EPOE50在体外略微刺激了B16肿瘤细胞的增殖，但在体内，施用EPOE50可剂量依赖性地抑制B16黑色素瘤的生长。综上所述，我们的结果表明EPOE50增强了NK细胞活性，并且给小鼠施用EPOE50可能通过激活NK细胞抑制了肿瘤生长，还表明活性物质是一种含糖的寡聚物或聚合物，并非源自细菌。
