title: In vitro actions on human cancer cells and the liquid chromatography-mass spectrometry/mass spectrometry fingerprint of phytochemicals in rice protein isolate.
abstract: Rice protein isolate (RPI) has been reported to reduce the incidence of 7,12-dimethylbenz[a]anthracene-induced mammary tumors in rats. To determine the potential role of phytochemicals associated with the RPI, we studied in vitro antitumor activities of an ether fraction from RPI using human tumor cell lines, including two human breast carcinoma cell lines (MDA-MB-453 and MCF-7) and two myeloma cell lines (RPMI-8226 and IM-9). Concentration-dependent antiproliferative effects of the ether fraction were observed in all cell lines using the standard 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Fraction-induced apoptosis (P < 0.05) was detected in all cell lines, and this was associated with the induction of proapoptotic bax protein and cdk inhibitors (p21) and the suppression of cdk4 and cyclin D1 activity. Liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) with both positive and negative modes was used to analyze the phytochemicals in the ether fraction from RPI. Fifty-seven phytochemicals were identified or characterized by their diagnostic fragmentation patterns and direct comparison with the authentic standards on the basis of electrospray ionization-MS/MS data. The major components bound to RPI were lysoglycerophospholipids, fatty acids, and fatty acid 3-[2-(2,3-dihydroxy-propoxycarbonyl)-2-hydroxy-ethoxy]-2-hydroxy-propyl esters.
authors.affiliation: Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, 1120 Marshall Street, Little Rock, Arkansas 72202, USA.
authors.forename: Shanggong
authors.initials: S
authors.lastname: Yu
authors.forename: Nianbai
authors.initials: N
authors.lastname: Fang
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Li
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Zhang
authors.forename: Hongfeng
authors.initials: H
authors.lastname: Luo
authors.forename: Martin
authors.initials: M
authors.lastname: Ronis
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Badger
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid; D019938:Cyclin D1 / Q000032:analysis; D051358:Cyclin-Dependent Kinase 4 / Q000032:analysis; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000032:analysis; D006801:Humans; D013058:Mass Spectrometry; D009101:Multiple Myeloma; D012275:Oryza / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis* / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000032:analysis
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D050759:Cyclin-Dependent Kinase Inhibitor p21; D010940:Plant Proteins; D051028:bcl-2-Associated X Protein; D019938:Cyclin D1; D051358:Cyclin-Dependent Kinase 4