| Abstract
| - Proliferation of human leukemic U937 cells was remarkably inhibited by conditioned medium (CM)of human peripheral blood mononuclear cells (MNC-CM) stimulated with cold-water extracts (CWE)(10−800 μg/mL of medium) of dietary mushrooms, Hypsizigus mamoreus (HM), Agrocybe aegerita(AA), Flammulina velutipes (FV), whereas insignificant results were observed when cells were culturedin the presence of CWE at the corresponding level. Water extracts from mushrooms were fractionatedby Sephadex G-50 chromatography, and the pooled high molecular weight fraction (F1) (200 μg/mL)of HM (HM1) and AA (AA1) exhibited growth inhibitions >80% on U937 cells. Interestingly, the thus-cultured U937 cells showed high nitroblue tetrazolium (NBT) positive (>68%) and nonspecific esterase(NSE) positive (>47%) percentages, revealing the remarkable differentiation into monocytes/macrophages upon incubation with HM1- and AA1-stimulated MNC-CM. In addition, assays for theexpressions of monocyte-associated antigens, CD11b, CD14, and CD68, also evidenced theremarkable differentiation of U937 cells into monocytes/macrophages by presenting high CD makerpositive percentages (>50%). Tumor necrosis factor (TNF)-α and interleukin (IL)-1β in CM of HM1-stimulated MNC for 1 day (MNC-CM-1) were 1350 and 1374 pg/mL, respectively, revealing the potentantitumor and differentiation-inducing activities of HM. Of note, MNC-CM-1 appeared to be moreeffective than day 5 MNC-CM (MNC-CM-5) in both antitumor and differentiation-inducing activities. Keywords: Antiproliferation; differentiation; leukemic U937; conditioned medium; mushrooms
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