Figure 4: Cell cycle inhibitory protein p21 gets repressed by sulforaphane in breast cancer cells. (a) Exponentially growing cells were exposed to different concentrations of sulforaphane for 24 h. Cells were harvested, total proteins were extracted and 50 μg protein was subjected to western blotting using antibodies against p21. Results showed repression of p21 with increasing concentrations of sulforaphane. β-actin was used as control to ensure equal loading of protein. (b) Gene promoter complex of cmyc and p21 were detected in response to sulforaphane. c-myc antibody was used to immunoprecipitate soluble chromatins from breast cancer cells cultured either with or without sulforaphane (20 μM) for 24 h. DNAs were immunoprecipitated and subjected to PCR using primers for the p21. Very poor binding ability of c-myc to the p21 promoter was observed. GAPDH gene was used as housekeeping gene. The results obtained are representatives of two or more experiments from independent immunoprecipitations.