title: Apoptosis induction associated with cell cycle dysregulation by rice bran agglutinin.
abstract: Effects of rice bran agglutinin (RBA) on human monoblastic leukemia U937 cells were examined in comparison with those of wheat germ agglutinin (WGA) and Viscum album agglutinin (VAA). These lectins inhibit cell growth, and several lines of evidence indicate that the growth inhibition is caused by the induction of apoptosis. We observed that RBA induces chromatin condensation, externalization of membrane phosphatidylserine, and DNA ladder formation, features of apoptosis. DNA ladder formation was inhibited by a general inhibitor against caspases, which are known to play essential roles in apoptosis. Flow cytometric analysis revealed that RBA and WGA cause G2/M phase cell cycle arrest with increased expression of Waf1/p21, while cell cycle arrest was not observed for VAA. These data indicate that RBA induces apoptosis associated with cell cycle arrest in U937 cells, and suggest that the induction mechanism for RBA is similar to that for WGA, but different from that for VAA.
authors.affiliation: Laboratory of Cellular Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Yada, Shizuoka 422-8526, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Miyoshi
authors.forename: Y
authors.initials: Y
authors.lastname: Koyama
authors.forename: Y
authors.initials: Y
authors.lastname: Katsuno
authors.forename: S
authors.initials: S
authors.lastname: Hayakawa
authors.forename: T
authors.initials: T
authors.lastname: Mita
authors.forename: T
authors.initials: T
authors.lastname: Ohta
authors.forename: K
authors.initials: K
authors.lastname: Kaji
authors.forename: M
authors.initials: M
authors.lastname: Isemura
mesh_terms: D017209:Apoptosis; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000819:agonists* / Q000096:biosynthesis; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects*; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D037102:Lectins / Q000494:pharmacology*; D016403:Lymphoma, Large B-Cell, Diffuse; D008938:Mitosis / Q000187:drug effects; D010718:Phosphatidylserines / Q000378:metabolism; D037121:Plant Lectins; D028321:Plant Preparations; D010940:Plant Proteins / Q000494:pharmacology*; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological / Q000494:pharmacology; D020298:U937 Cells; D014909:Wheat Germ Agglutinins / Q000494:pharmacology
chemical_list: C493956:CDKN1A protein, human; D002843:Chromatin; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D015853:Cysteine Proteinase Inhibitors; D037102:Lectins; D010718:Phosphatidylserines; D037121:Plant Lectins; D028321:Plant Preparations; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; D014909:Wheat Germ Agglutinins; C009674:ribosome inactivating protein, Viscum; C040599:rice lectin