Oridonin-induced ferroptosis and apoptosis: a dual approach to suppress the growth of osteosarcoma cell

Abstract

Background Osteosarcoma (OS) is one of the most common aggressive bone malignancy tumors in adolescents. With no significant advances in the treatment of OS in recent ten years, discovering new and effective anti-OS drugs became our top priority. Oridonin has been proved to mediate anti-tumor impact on OS cells, although it’s mechanism of action has not been fully understood.Methods Here, we investigated the inhibitory effect of oridonin on OS cells and its underlying mechanisms. In 143B and U2OS cells, oridonin’s pro-apoptosis and pro-ferroptosis effects on cell death, cell proliferation, cell migration, iron accumulation, mitochondrial membrane potential and lipid peroxidation production were observed. Western blot (WB) and real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) were used to detect the expression levels of apoptosis and ferroptosis-relative proteins and genes. Iron assay Kit was used to evaluate the relative Fe2+ content. The mitochondrial membrane potential detection kit and ROS assay kit were used to evaluate the levels of mitochondrial membrane potential and lipid peroxidation production. The changes of oridonin’s inhibitory on malignant phenotype of OS cells were examined after treating OS cells with the ferroptosis inhibitor ferrostatin-1 (Fer-1).Results Oridonin potently inhibited OS cells viability and metastasis. Simultaneously, oridonin suppressed the expressions of BAX, cl-caspase3, SLC7A11, GPX4 and FTH1 proteins and mRNA, while promoting the expressions of Bcl-2 and ACSL4 in 143 and U2OS cells. Furthermore, we found that oridonin also boosted the accumulation of reactive oxygen species (ROS), encouraged the buildup of Fe2+, and decreased the mitochondrial membrane potential in OS cells, but this effect can be reversed by Fer-1.Conclusion Oridonin can trigger apoptosis and ferroptosis collaboratively in OS cells, making it a promising and effective agent for OS therapy.