151. Inhibition of constitutively active Stat3 suppresses growth of human ovarian and breast cancer cells.
- Author
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Burke WM, Jin X, Lin HJ, Huang M, Liu R, Reynolds RK, and Lin J
- Subjects
- Blotting, Western, Breast Neoplasms genetics, Breast Neoplasms metabolism, Cell Division drug effects, Cell Line, Cell Size drug effects, Cisplatin pharmacology, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Electrophoretic Mobility Shift Assay, Epithelial Cells metabolism, Epithelial Cells pathology, Female, Fibroblasts metabolism, Fibroblasts pathology, Genes, Dominant, Humans, Janus Kinase 3, Mutation genetics, Ovarian Neoplasms genetics, Ovarian Neoplasms metabolism, Phosphorylation drug effects, Protein-Tyrosine Kinases antagonists & inhibitors, Protein-Tyrosine Kinases metabolism, Proto-Oncogene Proteins c-bcl-2 metabolism, STAT3 Transcription Factor, Signal Transduction drug effects, Time Factors, Trans-Activators genetics, Trans-Activators metabolism, Transfection, Tumor Cells, Cultured, Tyrphostins pharmacology, bcl-X Protein, Apoptosis drug effects, Breast Neoplasms pathology, DNA-Binding Proteins antagonists & inhibitors, Ovarian Neoplasms pathology, Trans-Activators antagonists & inhibitors
- Abstract
Signal transducers and activators of transcription (STATs) are transcription factors activated in response to cytokines and growth factors. Constitutively active Stat3 has been shown to mediate oncogenic transformation in cultured cells and induce tumor formation in mice. An increasing number of tumor-derived cell lines as well as samples from human cancer have been reported to express constitutively active Stat3 protein. We previously demonstrated that ovarian cancer cell lines express high levels of constitutively active Stat3. In this study, we show that inhibition of the Stat3 signaling pathway using the Janus Kinase-selective inhibitor, AG490, and a dominant negative Stat3 (Stat3beta) significantly suppresses the growth of ovarian and breast cancer cell lines harboring constitutively active Stat3. In the ovarian cancer cell lines, AG490 also diminished the phosphorylation of Stat3, Stat3 DNA binding activity, and the expression of Bcl-x(L). Further, AG490 induced significant apoptosis in ovarian and breast cancer cell lines expressing high levels of constitutively active Stat3 but had a less profound effect on normal cells lacking constitutively active Stat3. AG490 also enhanced apoptosis induced by cisplatin in ovarian cancer cells. These results suggest that inhibition of Stat3 signaling may provide a potential therapeutic approach for treating ovarian and breast cancers.
- Published
- 2001
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