Berry fruit extracts inhibit growth and induce apoptosis of high-risk acute lymphoblastic leukemia cells in vitro

Dark coloured fruits contain many phytochemicals that have anti-cancer activity. The ability of extracts of berry fruits to kill leukemia cell lines derived from patients with high-risk acute lymphoblastic leukemia (ALL) carrying the t(4;11)(q21;q23) chromosomal translocation was investigated. Extracts enriched in phenolic compounds were prepared from blackberries, blueberries, red, green, and black grapes, raspberries, and strawberry powder, and the leukemia-derived cell lines SEM, RS4;11, and REH were treated with 0, 25, 50, and 100 μg/ml of each berry extract daily for a total of 72 h. Mitochondrial membrane depolarization, cell death, cell cycle, and nitric oxide generation in response to treatment were measured by flow cytometry. Extracts from blackberries, blueberries, red and black grapes, and strawberry powder induced varying levels of apoptotic cell death in the leukemia cells. For most treatments, cell death was accompanied by an arrest in the G2/M phase of the cell cycle. An S phase arrest was also observed for SEM and REH cells treated with strawberry or blackberry extract. Our data suggest that phenolic phytochemicals found in berry fruits may have substantial potential for the prevention or treatment of high-risk ALL and further evaluations are warranted in vivo.