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Astaxanthin Induces Apoptosis in Human Osteosarcoma MG-63 Cells
Guangyu Wang1, Xu Tian1, Lintao Liu1
1Tianjin Hospital, Trauma Upper Limb 2 Department, Tianjin, China.
Abstract:
We explored the mechanism of human osteosarcoma MG-63 cell apoptosis induced by asta-xanthin. The MTT assay was used to detect the effect of astaxanthin on cell viability. Morphological changes associated with apoptosis were observed after DAPI staining. Early and late stages of apoptosis were detected by flow cytometry with annexin V-FITC/PI staining. Activation of caspases-8, -9 and -3 was detected by enzyme activity in vitro. Changes in the mitochondrial membrane potential were detected by MitoCapture staining. Western blot was used to detect the cleavage of PARP, which is a caspase-3 substrate, the release of cytochrome c and Smac into the cytosol, the translocation of pro-apoptotic proteins Bax and Bak, and the expression of mitochondrial pathway-related proteins. The translocation of Bax was also detected by immunofluorescence assay. Astaxanthin significantly inhibited the viability of human osteosarcoma MG-63 cells with an IC50 value of 12.36 μg/ml. The DAPI-stained cells showed characteristic apoptotic morphological changes - cell shrinkage, cell membrane blebbing, nuclear condensation, and apoptotic body formation. Cytochrome c and Smac were released from mitochondria to the cytosol. Pro-apoptotic proteins Bax and Bak were rapidly translocated to mitochondria after six hours of astaxanthin action. Caspases-9 and -3 were activated and PARP was cleaved. The expression of anti-apoptotic proteins Bcl-2, Bcl-xL and XIAP was significantly decreased. Astaxanthin induced human osteosarcoma MG-63 cell apoptosis through the mitochondria-mediated endogenous apoptosis pathway.
Insights
Astaxanthin effectively induces apoptosis in human osteosarcoma MG-63 cells by activating the mitochondrial pathway. This natural compound inhibits cell viability and triggers key events in programmed cell death.
Area of Science:
- Oncology
- Cell Biology
- Biochemistry
Background:
- Osteosarcoma is a primary bone cancer with limited treatment options.
- Astaxanthin, a natural carotenoid, exhibits potential anti-cancer properties.
- Understanding astaxanthin's mechanism in osteosarcoma is crucial for therapeutic development.
Purpose of the Study:
- To elucidate the apoptosis-inducing mechanism of astaxanthin in human osteosarcoma MG-63 cells.
- To investigate the role of the mitochondrial pathway in astaxanthin-mediated apoptosis.
- To evaluate astaxanthin's effect on cell viability and apoptotic markers.
Main Methods:
- MTT assay for cell viability.
- DAPI staining and flow cytometry (Annexin V-FITC/PI) for apoptosis detection.
- Western blot and enzyme activity assays for caspase activation, protein expression, and mitochondrial pathway analysis.
- MitoCapture staining for mitochondrial membrane potential.
Main Results:
- Astaxanthin significantly inhibited MG-63 cell viability (IC50 = 12.36 μg/ml).
- Characteristic apoptotic morphological changes, including nuclear condensation and blebbing, were observed.
- Astaxanthin induced cytochrome c and Smac release, Bax/Bak translocation, caspase-9 and -3 activation, and PARP cleavage.
- Expression of anti-apoptotic proteins (Bcl-2, Bcl-xL, XIAP) was decreased.
Conclusions:
- Astaxanthin induces apoptosis in human osteosarcoma MG-63 cells.
- The mechanism involves the activation of the mitochondria-mediated endogenous apoptosis pathway.
- Astaxanthin shows promise as a potential therapeutic agent for osteosarcoma.
