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Hypoxia-inducible Factor-1α Suppression in Ovarian Clear-cell Carcinoma Cells by Silibinin Administration
Mariko Miyazawa1, Masanori Yasuda2, Masaki Miyazawa1
1Department of Obstetrics and Gynaecology, Tokai University School of Medicine, Kanagawa, Japan.
Background/Aim:
Advanced ovarian clear-cell carcinoma (CCC) fails to respond to standard chemotherapy, and has a poor prognosis. Since hypoxia-inducible factor-1 (HIF-1) stimulates various genes involved in cancer, we aimed to examine the efficacy of silibinin, an active component of milk thistle belonging to Asteraceae, in suppressing HIF-1 activity, and elucidate the underlying mechanism in human CCC cell lines.
Materials And Methods:
Human ovarian CCC cell lines HAC-2, OVISE, and RMG-1 were treated with 500 μM silibinin for 4 h under normoxic and hypoxic conditions. Using DNA microarray, we analysed genes whose expression modulated more than 2-fold in response to hypoxia, whereas HIF-1α expression was measured using ELISA.
Results:
Silibinin treatment decreased HIF-1α protein in all cell lines, and eIF4E2 and RPS6 mRNA in HAC-2 and RMG-1 cells.
Conclusion:
Silibinin suppressed HIF-1α protein under hypoxic conditions in CCC cell lines and could be a potential anti-cancer drug.
Insights
Silibinin, a milk thistle component, reduced hypoxia-inducible factor-1 alpha (HIF-1α) protein in ovarian clear-cell carcinoma (CCC) cells. This suggests silibinin may be a potential anti-cancer drug for treating this aggressive cancer.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Advanced ovarian clear-cell carcinoma (CCC) is resistant to chemotherapy, leading to poor patient outcomes.
- Hypoxia-inducible factor-1 (HIF-1) is implicated in cancer progression and gene regulation.
- Identifying novel therapeutic targets for CCC is crucial.
Purpose of the Study:
- To investigate the anti-cancer effects of silibinin, a milk thistle extract, on human CCC cell lines.
- To determine if silibinin can suppress HIF-1 activity, a key factor in cancer development.
- To elucidate the molecular mechanisms underlying silibinin's action in CCC.
Main Methods:
- Human ovarian CCC cell lines (HAC-2, OVISE, RMG-1) were treated with silibinin (500 μM) under normoxic and hypoxic conditions.
- DNA microarray analysis was employed to identify genes modulated by hypoxia.
- HIF-1α protein levels were quantified using ELISA.
Main Results:
- Silibinin treatment significantly decreased HIF-1α protein levels in all tested CCC cell lines.
- The expression of eIF4E2 and RPS6 mRNA was reduced by silibinin in HAC-2 and RMG-1 cells.
- Silibinin demonstrated inhibitory effects on HIF-1α under hypoxic conditions.
Conclusions:
- Silibinin effectively suppresses HIF-1α protein expression in ovarian clear-cell carcinoma cells under hypoxia.
- These findings indicate that silibinin holds potential as an anti-cancer therapeutic agent for CCC.
- Further research into silibinin's mechanisms could lead to new treatment strategies for ovarian cancer.
