Article Figures & Data
Figures
- Figure 1.
Effect of Sulforaphane (SFN) analogues on the growth and viability of colon cancer cells. A: HCT116 and B: LoVo, HT29 and Caco-2 cells. At 72 h post-incubation with different SFN analogues, the growth and viability of cells was determined by MTT assay. Results are expressed as the percentage growth (mean±S.D. of triplicate wells) relative to control (DMSO-treated) cells.
- Figure 2.
Differential degree of apoptosis induction by SFN analogues in HCT116 cells. At 30 h post-incubation with DMSO or the indicated doses of SFN analogues, A: Apoptosis quantified by an ELISA. The bar represents the ratio of the absorbance at 405 nm in cells incubated with SFN analogue and in vehicle-treated control (CTL) cells (mean±SD of two experiments performed in duplicate). B: Percentages of cells accumulated in the sub-G1 phase analysed as described in the text. Significant differences are indicated by asterisks: *p<0.05, compared with control cells.
- Figure 3.
Effect of SFN analogues on ROS generation (A, B) and apoptosis induction (C). A: ROS generation by SFN analogues. HCT116 cells were treated with 12 μM of erysolin, SFN or erucin overnight prior to ROS generation. ROS data are expressed as the increase in channel fluorescence of treated cells relative to vehicle-treated cells. Effect of pretreatment with antioxidant NAC or GSH-depletion agent BSO on the ROS generation (B) and apoptosis induction (C) by erysolin. HCT116 cells were pretreated with BSO or NAC for 2 h before treating cells with 12 μM erysolin overnight and subjected to ROS analysis or apoptosis analysis. Results are from duplicate assays in each of at least two independent experiments (mean±SD) **p<0.01 by unpaired t-test.
- Figure 4.
Erysolin-induced apoptosis was caspase 8 dependent. A: Effect of erysolin or erucin on the expression of procaspase 8 and 9. At 24 h post-incubation of HCT116 cells with each SFN analogue, the procaspase expression was determined by immunoblot analysis. B: Effect of erysolin or erucin on the activity of caspase 8. Caspase 8 activity assay was performed after 24-h treatment. C: Effect of pretreatment with a general caspase inhibitor z-VAD-fmk or caspase 8 inhibitor z-IETD-FMK on the apoptotic cell death induced by erysolin. After 2-h pretreatment with 25 μM of the appropriate caspase inhibitor, cells were treated with 12 μM erysolin for for 24 h prior to apoptosis analysis. D: Effect of erysolin on the apoptosis induction in HCT116 cells stably transfected with empty plasmid vector (HCT116/CTL) or with plasmid containing dominant negative caspase 8 gene (HCT116/FLICE-DN). Apoptosis assay was performed after incubation with erysolin for 24-h (mean±SD). **p<0.01 by unpaired t-test. Insets, (D) Immunoblots for FLAG and procaspase-8 in HCT116/CTL and HCT116/FLICE-DN cells to determine the expression level of dominant negative caspase 8 protein.
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