Cyanidin 3-O-glucoside Induces Apoptosis on Osteosarcoma Cells through Upregulation of PPARγ and P21: An In vitro Study

Background: Osteosarcoma is known as the malignant tumors of bone which can occur in all ages by the peak incidence in the childhood. While consensus genetic alterations which lead to generate of the osteosarcoma are not well clarified, dysregulations in some tumor suppressor genes including Rb is observed in most of the osteosarcomas. Drug resistance is an important phenomenon which occurs in osteosarcoma. Peroxisome proliferator-activated receptor (PPARγ) is believed to inhibit proliferation and induce apoptosis in bone malignant cells. Within an antioxidant/anticancer properties, Cyanidin 3-O-glucoside (C3G) has a powerful ability to induce apoptotic cell death in the different cancer cells however the mechanisms of action for C3G have not been clarified yet. In this study, we have investigated the apoptotic effects of C3G on three different osteosarcoma cell lines including Saso-2, MG-63, G-292 (clone A141B1). Furthermore, we have investigated changes in the expression level of important genes including PPARγ, Rb, P21, Bax, and Bcl-xl.Methods: The 24 hours LD50 of C3G for Saso-2, G-292, and MG-63 cells was evaluated by MTT assay. Apoptosis induction in these cell lines after treatment with C3G approved by the way of Annexin V/PI flow cytometry. Changes at the mRNA expression level of PPARγ, Rb, P21, Bax, and Bcl-xl genes have investigated by real-time PCR technique, as well as P21 expression was further confirmed by western blotting.Results: The MTT assay results have demonstrated that the 24 hours LD50 of C3G for Saso-2 and G-292 cells was 110 μg/ml while it was about 140 μg/ml for the MG-63 cells. The results of real-time PCR have clearly shown that treatment of the cells with 24 hours LD50 of C3G case to upregulation of PPARγ, Rb, P21, and Bax genes. Also, western blot analyzing confirmed that P21 protein overexpressed endogenously after treatment of cells with C3G which it was more upregulated in MG-63 cells compared to the other cell lines.Conclusion: The final outcomes of our study powerfully introduce the C3G as a novel anti-osteosarcoma agent with the ability to induce apoptosis in different osteosarcoma cells via upregulation of the PPARγ and the P21.

Keywords:

Osteosarcoma , Cyanidin 3-O-glucoside , PPARγ , P21 , apoptosis