AUTHOR=Ren Tianhao , Huang Ju , Sun Wei , Wang Guangze , Wu Yuwen , Jiang Zewei , Lv Yingshuai , Wu Guang , Cao Jiawei , Liu Min , Gu Haihua 

TITLE=Zoledronic acid induces ferroptosis by reducing ubiquinone and promoting HMOX1 expression in osteosarcoma cells

JOURNAL=Frontiers in Pharmacology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2022.1071946

DOI=10.3389/fphar.2022.1071946

ISSN=1663-9812

ABSTRACT=<p><bold>Aims:</bold> Ferroptosis plays important roles in tumorigenesis and cancer therapy. Zoledronic acid is known to inhibit the activity of farnesyl pyrophosphate synthase, a key enzyme in the mevalonate pathway. We examined whether zoledronic acid can inhibit the growth of osteosarcoma cells by inducing ferroptosis.</p><p><bold>Methods</bold>: Cell viability was analyzed by using CCK8 reagent and counting cells with trypan blue exclusion. Ferroptosis markers including lipid peroxide and <italic>PTGS2</italic> expression were examined by flow cytometry, western blot, and quantitative PCR analyses. Cellular ubiquinone content was determined using high performance liquid chromatography. Ferrostatin-1 and RSL3 were used as the ferroptosis inhibitor and inducer respectively.</p><p><bold>Results</bold>: Zoledronic acid treatment decreased cell viability and promoted the increase in lipid peroxide content and <italic>PTGS2</italic> expression. Addition of ferrostatin-1 reverted these effects of zoledronic acid on osteosarcoma cells, supporting a role of zoledronic acid in inducing ferroptosis. Mechanistically, zoledronic acid significantly decreased ubiquinone, a metabolite of the mevalonate pathway. Treating cells with exogenous ubiquinone prevented zoledronic acid-induced ferroptosis and decrease in the growth of osteosarcoma cells. In addition, zoledronic acid enhanced the expression of HMOX1, whereas knockdown of HMOX1 inhibited the zoledronic acid-induced increase in lipid peroxide level and decrease in cell growth. Finally, zoledronic acid together with RSL3 significantly enhanced the inhibitory effect on the growth of osteosarcoma cells.</p><p><bold>Conclusion:</bold> Our results indicate that zoledronic acid induces ferroptosis by decreasing ubiquinone content and promoting HMOX1 expression in osteosarcoma cells. Zoledronic acid together with ferroptosis inducer may be a promising new strategy for the treatment of osteosarcoma.</p>