SMPD1 modulates malignant progress of osteosarcoma through ferroptosis pathway

Osteosarcoma is characterized by its high malignancy and poor prognosis, underscoring the importance of exploring its underlying molecular mechanisms. While Sphingomyelin phosphodiesterase 1 (SMPD1) is essential in the development of tumors, the specific functions and mechanisms related to osteosarcoma progression are still not well comprehended. This research intends to elucidate SMPD1's role and mechanism in osteosarcoma development and progression. Through a series of experiments, we discovered that SMPD1 was highly expressed in osteosarcoma cells and that knocking down SMPD1 significantly restricted cell viability, invasion, and migration. Concurrent with these changes, we observed alterations in ferroptosis-related indicators, including increased levels of cellular ferrous iron (Fe^2 +), reactive oxygen species (ROS), and lipid peroxides, as well as reduced glutathione levels. Furthermore, the expression of ferroptosis marker genes was modified, and these effects could be significantly reversed by the ferroptosis inhibitor Fer-1. Additionally, silencing SMPD1 upregulated the ACSL4/LPCAT3/ALOX15 axis of lipid metabolism in ferroptosis, an effect that could be counteracted by the ALOX15 inhibitor ML351. Overall, our findings suggest that the silencing of SMPD1 enhances ferroptosis via the ACSL4/LPCAT3/ALOX15 axis, leading to reduced viability, migration, invasion, and tumor growth of osteosarcoma cells. These novel insights may have significant implications for the clinical treatment of osteosarcoma.