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Figure 3 | Molecular Cancer

Figure 3

From: Berberine modulates AP-1 activity to suppress HPV transcription and downstream signaling to induce growth arrest and apoptosis in cervical cancer cells

Figure 3

Berberine specifically downregulates constitutive active AP-1 in HPV18 positive cervical cancer cells. A, Dose-dependent downregulation of AP-1 binding activity. Nuclear proteins of HeLa cells treated without or with indicated concentrations of berberine for 24 h were prepared and assayed for AP-1 DNA binding activity by EMSA. As indicated in "Methods" fold change was calculated following densitometric evaluation of shifted band. B, Binding of AP-1 to its consensus oligo probe is specific. Binding specificity of AP-1 to its consensus probe was examined by cold competition in a binding reaction of untreated HeLa nuclear proteins and labeled AP-1 probe adding 100 fold molar excess of unlabeled homologous AP-1 probe or heterologous Oct-1 probe. C, Berberine changes composition of AP-1 DNA-binding complex in HeLa cells. Equal amount of nuclear extracts (10 μg/lane) isolated from untreated as well as treated (100 μg/ml berberine for 18 h) HeLa cells were checked for binding partners in functional AP-1 complex by co-incubating these extracts individually with different antibodies as described in 'Methods'. (*Excess of nuclear proteins used to reveal participation of AP-1 members.) D, Effect of berberine on the expression of AP-1 family proteins. HeLa cells treated with berberine for indicated doses and protein isolated from these cells were subjected to western blot analysis as described in "Methods". β-actin was used as loading control. The abundance ratio to β-actin was analyzed by densitometry. The data are expressed as the mean ± SD of 3 independent experiments.

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