Dual Mechanism of Action of Resveratrol in Notch Signaling Pathway Activation in Osteosarcoma

Purpose: To demonstrate the effect of resveratrol on Notch signaling in MG-63 and U2OS osteosarcoma cell lines.
Methods: Cell Counting Kit 8 reagent was used to analyze cell proliferation while TRIzol® reagent was employed for the extraction of total RNA. High Capacity cDNA reverse transcription chain reaction kit was used to transcribe 2 μg RNA. Western blot analysis was performed to examine Hes1 and Hey1 expression.
Results: The results revealed that resveratrol treatment exhibited dual mechanisms of action on the activation of Notch signaling in osteosarcoma cells. The osteosarcoma cell lines, MG-63 and U2OS, when exposed to 20 μM concentration of resveratrol for 48 h showed significant toxicity compared to untreated cells. However, 30 μM concentration of resveratrol induced higher toxicity which was lethal to cell growth. The results from RT qPCR and Western blot data revealed a concentration-dependent effect of resveratrol on the expression of Notch signaling genes including Hes1, Hes5, Hey1, Hey2 and HeyL in U2OS cells. Treatment of U2OS cells with 20 μM concentration of resveratrol for 48 h induced a marked increase in the expression of Hes1, Hes5, Hey1, Hey2 and HeyL mRNA compared to the untreated cells. However, at a concentration of 30 μM, resveratrol inhibited the activation of Notch signaling pathway. This was evident by a decrease in the expression of Hes1, Hes5, Hey1, Hey2 and HeyL, Notch signaling target genes.
Conclusion: Resveratrol plays an important role in the activation of Notch signaling pathway and may be of therapeutic benefit in the treatment of osteosarcoma.

Keywords
Osteosarcoma; Dual action mechanism; Notch signaling pathway; Toxicity; Cell growth inhibition