Begoña Comín-Anduix, László G. Boros§, Silvia Marin, Joan Boren, Carles Callol-Massot, Josep J. Centelles, Josep L. Torres¶, Neus Agell, Sara Bassilian§, and Marta Cascante
From the Department of Biochemistry and Molecular Biology, CeRQT-PCB at Barcelona Scientific Park, University of Barcelona, 1 Martí i Franquès, Barcelona 08028, Spain, the § Harbor-UCLA Research and Education Institute, University of California, Los Angeles, School of Medicine, Torrance, California 90502, the ¶ Department of Peptide and Protein Chemistry, Institute for Chemical and Environmental Research (IIQAB-CSIC), C/Jordi Girona 18-26, 08034-Barcelona, Spain, and the Department of Cell Biology, IDIBAPS, Faculty of Medicine, University of Barcelona, Casanova 143, E-08036, Barcelona, Spain
The fermented extract of wheat germ, trade name Avemar, is a complex mixture of biologically active molecules with potent anti-metastatic activities in various human malignancies. Here we report the effect of Avemar on Jurkat leukemia cell viability, proliferation, cell cycle distribution, apoptosis, and the activity of key glycolytic/pentose cycle enzymes that control carbon flow for nucleic acid synthesis. The cytotoxic IC50 concentration of Avemar for Jurkat tumor cells is 0.2 mg/ml, and increasing doses of the crude powder inhibit Jurkat cell proliferation in a dose-dependent fashion. At concentrations higher than 0.2 mg/ml, Avemar inhibits cell growth by more than 50% (72 h of incubation), which is preceded by the appearance of a sub-G1 peak on flow histograms at 48 h. Laser scanning cytometry of propidium iodide- and annexin V-stained cells indicated that the growth-inhibiting effect of Avemar was consistent with a strong induction of apoptosis. Inhibition by benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone of apoptosis but increased proteolysis of poly(ADP-ribose) indicate caspases mediate the cellular effects of Avemar. Activities of glucose-6-phosphate dehydrogenase and transketolase were inhibited in a dose-dependent fashion, which correlated with decreased 13C incorporation and pentose cycle substrate flow into RNA ribose. This decrease in pentose cycle enzyme activities and carbon flow toward nucleic acid precursor synthesis provide the mechanistic understanding of the cell growth-controlling and apoptosis-inducing effects of fermented wheat germ. Avemar exhibits about a 50-fold higher IC50 (10.02 mg/ml) for peripheral blood lymphocytes to induce a biological response, which provides the broad therapeutic window for this supplemental cancer treatment modality with no toxic effects.