Urolithin B inhibits proliferation and migration and promotes apoptosis and necrosis by inducing G2/M arrest and targeting MMP-2/-9 expression in osteosarcoma cells.

Osteosarcoma (OS) is the most prevalent primary bone cancer, with a high morbidity and mortality rate. Over the past decades, therapeutic approaches have not considerably improved patients' survival rates, and further research is required to find efficient treatments for OS. Data from several studies have shown that urolithin B (UB), the intestinal metabolite of polyphenolic ellagitannins, is emerging as a new class of anticancer compounds, yet its effect on OS cancer cells remains elusive. Herein, we investigated UB's antimetastatic, antiproliferative, and apoptotic effects on the MG-63 OS cell line. Cell viability assay, annexin V/propidium iodide staining, cell cycle arrest analysis, determination of the gene expression of MMP-2, MMP-9, Bax, Bcl-2, and p53 messenger RNA (mRNA), evaluation of reactive oxygen species (ROS) generation and migration, and MMP-2 and MMP-9 protein expression assessments were performed. UB caused late apoptosis, necrosis, G2/M arrest, and ROS generation in MG-63 cells. It increased the mRNA expression of the p53 tumor suppressor and Bax proapoptotic genes. UB also inhibited the migration and metastatic behavior of MG-63 OS cells by downregulating mRNA and MMP-2 and MMP-9 protein expression. In general, although further in vivo investigations are warranted, the current results showed that UB might be utilized as a potential novel natural compound for OS therapy due to its nontoxic, antiproliferative, and antimetastatic nature.