Cisplatin and doxorubicin repress Vascular Endothelial Growth Factor expression and differentially down-regulate Hypoxia-inducible Factor I activity in human ovarian cancer cells
Vascular Endothelial Growth Factor (VEGF ) and its transcriptional regulator Hypoxia-inducible Factor 1 (HIF-1) play an important role in the process of angiogenesis in many types of cancer, including ovarian cancer. We have examined whether the DNA-damaging drugs cisplatin and doxorubicin and the m...
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Veröffentlicht in: | Biochemical pharmacology 2007-07, Vol.74 (2), p.191-201 |
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Zusammenfassung: | Vascular Endothelial Growth Factor (VEGF
) and its transcriptional regulator Hypoxia-inducible Factor 1 (HIF-1) play an important role in the process of angiogenesis in many types of cancer, including ovarian cancer. We have examined whether the DNA-damaging drugs cisplatin and doxorubicin and the microtubule inhibitors docetaxel and paclitaxel can affect VEGF expression and HIF-1 activity in three human ovarian cancer cell lines. We demonstrate that cisplatin and doxorubicin abolish hypoxia-induced VEGF mRNA expression in all cell lines, while basal VEGF mRNA expression was also downregulated. Transient transfection with a HIF-1-responsive luciferase construct indicated that cisplatin and doxorubicin inhibited hypoxic activation of HIF-1. Cisplatin repressed HIF-1α protein expression in all cell lines. Stimulation of HIF-1α protein degradation by cisplatin was observed in the only cell line expressing wild-type p53. Cisplatin also inhibited the synthesis of HIF-1α protein for which p53 was dispensable. Interestingly, cisplatin strongly reduced the protein levels of the HIF-1 coactivators p300 and CREB-binding protein (CBP) under hypoxia in all cell lines. Although doxorubicin inhibited hypoxic activation of HIF-1, this drug had no significant effect on the expression levels of HIF-1α and hypoxic expression of p300 and CBP was only weakly reduced. Docetaxel and paclitaxel did neither influence VEGF expression nor hypoxia-induced HIF-1 activity. In total, our findings indicate that cisplatin and doxorubicin can repress hypoxic induction of VEGF expression by inhibiting HIF-1 through different mechanisms. This knowledge may be useful for future treatment schedules including agents that target the HIF-1 signalling pathway. |
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ISSN: | 0006-2952 1873-2968 |
DOI: | 10.1016/j.bcp.2007.04.003 |