Fig. 3. Effects of endosulfan on the CYP1A1 regulatory mechanism. (A) Effects of endosulfan on XRE promoter activity in Hepa-1c1c7 cells. Cells were transfected with the XRE-Luc construct and subsequently treated with endosulfan (Endo) or 3-MC for 18 h. Cells were then harvested and assayed for luciferase activity. Values represent the means from three independent experiments, each performed in triplicate. * p<0.01, significantly different from the control, as determined by ANOVA by the Newman-Keuls test. (B) Effects of an AhR antagonist on XRE transcriptional activity by endosulfan in Hepa-1c1c7 cells. Cells were transfected with XRE-Luc and treated with CH-223191 (CH), endosulfan or 3-MC for 18 h. Cells were then harvested and assayed for luciferase activity. Values represent the means from three independent experiments, each performed in triplicate. * p< 0.01, ** p < 0.01, and # p < 0.01, significantly different from the control, 3-MC, and endosulfan, as determined by ANOVA by the Newman-Keuls test. (C) Effects of an AhR antagonist on CYP1A1 protein levels by endosulfan in Hepa-1c1c7 cells. Cells were pretreated with CH-223191 for 30 min and then treated with endosulfan or 3-MC for 24 h. The membrane was probed with a CYP1A1-specific antibody, and bands were visualized with ECL reagents. (D) Effects of endosulfan on CYP1A1 mRNA levels in Tao BpRcl cells. Hepa-1c1c7 and Tao BpRcl cells were treated with endosulfan or 3-MC for 6 h. Values represent the means from three independent experiments, each performed in triplicate. * p< 0.01, significantly different from the control, as determined by ANOVA by the Newman-Keuls test.
