title: Antitumor effects of a water-soluble extract from Maitake (Grifola frondosa) on human gastric cancer cell lines.
abstract: We investigated the effects of a water-soluble extract of Maitake (Grifola frondosa), a Japanese edible mushroom, on the proliferation and cell death of four human gastric cancer cell lines (TMK-1, MKN28, MKN45 and MKN74). The Maitake extract (ME) inhibited the proliferation of all four cell lines in a time-dependent manner. The inhibition was most pronounced in TMK-1 cells, which exhibited up to 90% inhibition after treatment with 10% ME for 3 days. Staining of ME-treated TMK-1 cells with Hoechst 33258 revealed increased numbers of nuclear condensations and apoptotic bodies. Induction of apoptosis was confirmed by fluorescence-activated cell sorting analyses. Western blot analyses of TMK-1 cells after ME treatment revealed increases in intracytoplasmic cytochrome c and cleavage of caspase-3 and poly(ADP-ribose) polymerase, but no expression of p21 or Bax. The caspase-3 protease activities in lysates of TMK-1 cells treated with 1% or 10% ME were about three times higher than those in control cells. The proliferation of TMK-1 cells was hardly affected by the caspase-3 inhibitor z-DEVD-fmk. Taken together, these results suggest that ME induces apoptosis of TMK-1 cells by caspase-3-dependent and -independent pathways, resulting in potential antitumor effects on gastric cancer.
authors.affiliation: Division of Organ Pathology, Department of Microbiology and Pathology, Faculty of Medicine, Tottori University, Yonago, Tottori 683-8503, Japan. shomori@med.tottori-u.ac.jp
authors.forename: Kohei
authors.initials: K
authors.lastname: Shomori
authors.forename: Mako
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Ichiro
authors.initials: I
authors.lastname: Arifuku
authors.forename: Kazuki
authors.initials: K
authors.lastname: Teramachi
authors.forename: Hisao
authors.initials: H
authors.lastname: Ito
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000502:physiology; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D048691:Grifola; D006801:Humans; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; D045304:Cytochromes c; D053148:Caspase 3