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International Journal of Medicinal Mushrooms
IF: 1.423 5-Year IF: 1.525 SJR: 0.431 SNIP: 0.661 CiteScore™: 1.38

ISSN Print: 1521-9437
ISSN Online: 1940-4344

International Journal of Medicinal Mushrooms

DOI: 10.1615/IntJMedMushr.v7.i12.190
pages 201-212

Involvement of G2/M Cell Cycle Arrest and the Mitochondrial Pathway in Boletopsis leucomelaena (Pers.) Fayod (Agaricomycetideae) Lectin-Induced Apoptosis of Human Leukemia U937 Cells

Yu Koyama
Department of Cellular Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Yada, Shizuoka, Japan
Takuji Suzuki
Department of Cellular Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Yada, Shizuoka, Japan
Akane Kajiya
Department of Cellular Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Yada, Shizuoka, Japan
Mamoru Isemura
Department of Cellular Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Yada, Shizuoka, Japan

ABSTRACT

Boletopsis leucomelaena lectin (BLL) is the first example of an apoptosis-inducing lectin of mushroom origin. Because it is not clear how apoptosis is induced by any lectin, we investigated the mechanism of apoptosis induction by BLL in human leukemic U937 cells. BLL was found to cause G2/M cell cycle arrest in U937 cells. This arrest was associated with the upregulation of p21/Waf1 expression. The observed decrease in the expression of Bcl-2 was compatible with the upregulated expression of p21/Waf1 and correlated to the enhanced release of cytochrome c from mitochondria to cytoplasm, leading to the activation of caspase-9 in BLL-treated U937 cells. These results provide the first example of a mushroom lectin whose apoptosis-inducing mechanism involves cell cycle arrest and the mitochondrial pathway.