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Beta-sitosterol sensitizes MDA-MB-231 cells to TRAIL-induced apoptosis
Cheol Park1, Dong-oh Moon, Chung-ho Ryu
1Department of Biochemistry, Dongeui University College of Oriental Medicine, Busan 614-052, Korea.
Aim:
To investigate whether subtoxic concentration of beta-sitosterol (SITO) combined with TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis in TRAIL-resistant MDA-MB-231 breast cancer cells.
Methods:
Cell viability and growth were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphnyl-2H-tetrazolim bromide assays, chromatin condensation, release of lactate dehydrogenase (LDH), and Annexin V+ cells. The apoptosis-related proteins were detected by Western blotting.
Results:
Treatment with TRAIL in combination with subtoxic concentrations of SITO sensitized MDA-MB-231 breast cancer cells to TRAIL-mediated apoptosis. The synergistic treatment induced chromatin condensation, DNA fragmentation, the release of LDH, and Annexin V+ cells. The indicators of apoptosis are correlated to the induction of caspase activities, which results in the cleavage of poly(ADP-ribose)polymerase. Both the cytotoxic effects and apoptotic characteristics induced by the synergistic treatment were significantly inhibited by a pan-caspase inhibitor z-VAD-fmk, demonstrating the important role of caspases. These results indicate that caspases are crucial regulators of apoptosis induced by the combined treatment of SITO and TRAIL in MDA-MB-231 cells.
Conclusion:
The synergistic treatment of SITO and TRAIL induces apoptosis, which can serve as a potential preventive and therapeutic agent.
Insights
Beta-sitosterol (SITO) combined with TNF-related apoptosis-inducing ligand (TRAIL) effectively induces apoptosis in resistant breast cancer cells. This synergistic treatment offers potential as a novel therapeutic strategy for cancer treatment.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- TRAIL-resistant MDA-MB-231 breast cancer cells pose a therapeutic challenge.
- Beta-sitosterol (SITO) is a plant sterol with potential anti-cancer properties.
- TNF-related apoptosis-inducing ligand (TRAIL) is a key inducer of apoptosis.
Purpose of the Study:
- To investigate the synergistic effect of SITO and TRAIL on apoptosis induction in TRAIL-resistant breast cancer cells.
- To determine the role of caspases in SITO-TRAIL-mediated apoptosis.
Main Methods:
- Cell viability assays (MTT).
- Assessment of apoptosis markers: chromatin condensation, lactate dehydrogenase (LDH) release, Annexin V staining.
- Western blotting to detect apoptosis-related proteins and caspase activation.
- Inhibition studies using a pan-caspase inhibitor (z-VAD-fmk).
Main Results:
- Subtoxic concentrations of SITO sensitized MDA-MB-231 cells to TRAIL-induced apoptosis.
- The combination treatment significantly increased apoptosis markers and induced DNA fragmentation.
- Caspase activation, including poly(ADP-ribose)polymerase cleavage, was essential for the observed cytotoxic effects.
- A pan-caspase inhibitor blocked the synergistic apoptotic effects, confirming caspase dependency.
Conclusions:
- SITO and TRAIL exhibit a synergistic effect in inducing apoptosis in TRAIL-resistant breast cancer cells.
- Caspase activation is a critical mechanism underlying this synergistic cell death.
- The combined SITO-TRAIL treatment shows promise as a potential preventive and therapeutic agent for breast cancer.
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