Background
Doxorubicin is the chemotherapeutic drug of choice in osteosarcoma treatment, but its cumulative administration causes dilated cardiomyopathy. Combination therapy represents a potential strategy to reduce the therapeutic dosage of the chemotherapeutic agent and minimize its side effects. The
Conclusion
The combined use of oridonin and doxorubicin could help to reduce the clinical dosage of doxorubicin and its dangerous side effects.
Methods
The combined administration of different doses of oridonin and doxorubicin, as compared with the drugs alone, were tested in an in vitro model of osteosarcoma. The synergistic effect of the drugs on cell death was assessed by alamarBlue™ and by CompuSyn software. Early and late apoptosis markers (JC-1 fluorescence and Annexin V immunofluorescence), as well as the production of reactive oxygen species, were evaluated by flow cytometry. Western blot was used to assess the expression of anti-apoptotic proteins.
Results
Oridonin and doxorubicin presented a synergistic cytotoxic effect in osteosarcoma cells. In the presence of sub-cytotoxic concentrations of the natural product, there was an increased accumulation of intracellular doxorubicin, increased levels of reactive oxygen species (ROS), alteration of mitochondria membrane potential and a higher rate of apoptosis.