Fig. 7: Upregulation of BIRC3 in ovarian cancer requires the STAT3 pathway. | Cell Death & Disease

Fig. 7: Upregulation of BIRC3 in ovarian cancer requires the STAT3 pathway.

From: Cul4 E3 ubiquitin ligase regulates ovarian cancer drug resistance by targeting the antiapoptotic protein BIRC3

Fig. 7: Upregulation of BIRC3 in ovarian cancer requires the STAT3 pathway.The alternative text for this image may have been generated using AI.

a Western blot detection of AKT, phosphorylated AKT, BIRC3, Caspace 3, and cleaved caspase-3 in A2780CP cells in the absence or presence of PI3K inhibitor LY294002 (40 μM) or cisplatin (12.5 μM). GAPDH serves as a loading control. A2780CP cells were cultured in six-well plates and pretreated with the LY294002 for 1 h before cisplatin addition. Total protein was extracted 24 h after treatment. Similar results were obtained from three independent experiments. b Western blot detection of STAT3, phosphorylated STAT3, BIRC3, Caspace 3, and cleaved caspase-3 in A2780CP cells in the absence or presence of STAT3 inhibitor S3I-201 (100 μM) or cisplatin (12.5 μM). GAPDH serves as loading control. A2780CP cells were cultured in six-well plates and pretreated with the STAT3 inhibitor S3I-201 for 1 h before cisplatin treatment. Total protein was extracted 24 h after cisplatin treatment. Similar results were obtained from three independent experiments. c and d Western blot detection of (c) DDB1, (d) Cul4A, (c and d) BIRC3, BIRC7, AKT, phosphorylated AKT, STAT3, phosphorylated STAT3, Caspace 3, and cleaved caspase-3 in A2780CP cells with (c) DDB1 or (d) Cul4A knockdown. GAPDH serves as a loading control. A2780CP cells were cultured in six-well plates and transfected with shRNA against DDB1 or Cul4A. Total protein was extracted 48 h after transfection. Similar results were obtained from three independent experiments. e and f Western blot detection of (e) DDB1, (f) Cul4A, and (e and f) STAT1 in A2780CP cells with (c) DDB1 or (d) Cul4A knockdown. GAPDH serves as a loading control. Knockdown procedure of Cul4A and DDB1 with shRNAs in A2780 cells is same as described above. g Immunoblot detection of STAT1 and STAT3 in input (lower panel) or immunoprecipitated (upper panel) samples in control or CRL4 (Cul4A/DDB1) knockdown A2780CP cells. GAPDH serves as a loading control. For immunoprecipitation, 2 μg antibody was used in each group. Precipitated STAT3 levels were quantified with Image J software and normalized to the control group (NT). h A model of CRL4 regulation on BIRC3 expression leading to chemoresistance in ovarian cancer

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