Effects Sulforaphane on IMR‐90 Phase II Enzyme Induction and Cell Senescence

Abstract

Sulforaphane (SF) derived from cruciferous vegetables induces expression of phase II antioxidant and detoxification enzymes including: quinone reductase (QR), ferritin and thioredoxin reductase. Aging cells accumulate iron, oxidized proteins and the cellular redox potential shifts to become increasingly oxidative. To study the effects of SF on aging cells, the IMR‐90 cell model of aging was used. IMR‐90 lung fibroblast cells are a non‐transformed cell line that exhibit the hallmarks of aging over time and become senescent after a finite number of culture passages. Moreover, time until IMR‐90 senescence can be modulated by oxidative stressors. Under standard culture conditions (19% O2) SF treatment (1, 2 and 4 μM) of IMR‐90 cells significantly increased QR reporter expression over controls by: 2.5±0.2, 2.9±0.1 and 3.2±0.2 respectively (P <0.001 for all treatments). When cells were cultured at 2% O2, SF treatment (1, 2 and 4 μM) induced reporter expression over controls by; 1.3±0.1 (P=0.011), 2.5±0.3 (P <0.001), and 3.3±0.3 (P <0.001) respectively. To determine the effect of SF on time until cell senescence, IMR‐90 cells were continuously cultured with 2 μM SF and subcultured weekly. Compared to controls, SF treatment delayed senescence by 2 cell culture passages. These preliminary data indicate that SF induces the IMR‐90 phase II enzyme system regardless of O2 tension and increases time until cell senescence.