Synergistic Effects of a Smac Mimetic with Doxorubicin Against Human Osteosarcoma
Etsuko Kamata1, Teruya Kawamoto2,3, Takeshi Ueha4
1Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Background/Aim:
Second mitochondria-derived activator of caspase (Smac) is a proapoptogenic mitochondrial protein that antagonizes inhibitors of apoptosis proteins (IAPs), resulting in induction of apoptosis. In the present study we investigated the effects of a Smac mimetic in combination with doxorubicin against osteosarcoma.
Materials And Methods:
In vitro effects of the combination of a Smac mimetic AT-406 and doxorubicin on cell proliferation and apoptosis in osteosarcoma cell lines were examined using cell proliferation assays, flow cytometry, and immunoblot analyses. For in vivo experiments, human osteosarcoma xenografts were treated with combination of the two substances, and tumor volume and apoptotic activity in treated tumors were assessed.
Results:
In vitro studies revealed that combination of the two substances significantly inhibited osteosarcoma proliferation with decreased cIAP1 expression and induced apoptosis in osteosarcoma cells. Combination of the two substances significantly suppressed osteosarcoma growth in vivo. Moreover, decreased cIAP1 expression and increased apoptotic activity were observed in tumors treated by their combination of the substances.
Conclusion:
The Smac mimetic AT-406 showed an apoptotic effect and a synergistic antitumor effect with doxorubicin on osteosarcoma. The combination of AT-406 and doxorubicin may serve as a novel therapeutic strategy for osteosarcoma treatment.
Insights
A Smac mimetic, AT-406, combined with doxorubicin effectively reduced osteosarcoma cell growth and induced apoptosis. This combination therapy shows promise for treating osteosarcoma.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Second mitochondria-derived activator of caspase (Smac) is a mitochondrial protein that promotes apoptosis by inhibiting apoptosis inhibitors (IAPs).
- Osteosarcoma is a primary bone cancer with limited treatment options.
Purpose of the Study:
- To investigate the efficacy of a Smac mimetic (AT-406) in combination with doxorubicin against osteosarcoma.
- To evaluate the synergistic antitumor effects of this combination therapy.
Main Methods:
- In vitro studies utilized osteosarcoma cell lines to assess proliferation and apoptosis.
- In vivo studies involved treating osteosarcoma xenografts in mice.
- Assays included cell proliferation assays, flow cytometry, and immunoblot analyses.
Main Results:
- The combination of AT-406 and doxorubicin significantly inhibited osteosarcoma cell proliferation and induced apoptosis in vitro.
- In vivo, the combination therapy significantly suppressed tumor growth.
- Decreased cellular inhibitor of apoptosis protein 1 (cIAP1) expression and increased apoptotic activity were observed in treated tumors.
Conclusions:
- The Smac mimetic AT-406 exhibits an apoptotic effect and synergistic antitumor activity with doxorubicin in osteosarcoma.
- The combination of AT-406 and doxorubicin represents a potential novel therapeutic strategy for osteosarcoma treatment.
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