Silencing of FZD7 Inhibits Endometriotic Cell Viability, Migration, and Angiogenesis by Promoting Ferroptosis.

Background: Endometriosis (EMS) is a difficult gynecological disease to cure. Frizzled-7 (FZD7) has been shown to be associated with the development of EMS, but its specific mechanism remains unclarified. This study aims to explore the role of FZD7 in EMS.

Methods: RT-qPCR and western blot were used to detect the expression level of FZD7 in human endometrial stromal cells (hESCs) and human ectopic endometrial stromal cell line hEM15A. The interfering plasmid of FZD7 was established. CCK-8, EdU, wound healing, transwell invasion, and cytoskeletal staining assays were applied to evaluate the role of FZD7 silencing in hEM15A cell proliferation, invasion, and migration. Tube forming ability of cells was evaluated by tube formation assay. Cellular VEGF, GSH, and MDA levels were measure by kits. Intracellular lipid ROS and Fe levels were tested using C11-BODIPY (581/591) and FeRhoNox-1 probes, respectively. The ferroptosis-related protein SLC7A11, GPX4, and ACSL4 expressions were analyzed using western blot. The effects of ferroptosis on endometriotic cell viability, migration, and angiogenesis were further analyzed with the addition of an ferroptosis inhibitor (Fer-1).

Results: FZD7 was upregulated in hEM15A cells, and silencing of FZD7 inhibited cell proliferation, migration, invasion, and angiogenesis abilities. Downregulation of FZD7 decreased cellular GSH level and elevated MDA level. Knockdown of FZD7 also caused an increase in intracellular ROS and Fe levels, as well as the downregulation of SLC7A11 and GPX4 levels and the upregulation of ACSL4 level, which are hallmarks of ferroptosis. However, the inhibitory effects of FZD7 knockdown on hEM15A cell progression were reversed when ferroptosis inhibitor Fer-1 added.

Conclusion: The above indices suggest that FZD7 knockdown regulates endometriotic cell proliferation, invasion, migration, and angiogenesis via ferroptosis.