Dihydroartemisinin Induces Ferroptosis in Ovarian Cancer via STAT3/GPX4 Signaling Pathway.

Objective: To investigate the effects and underlying mechanism of action of dihydroartemisinin (DHA) on ferroptosis in ovarian cancer (OC).

Methods: In vitro, SKOV3 and A2780 cells were treated with different concentrations of DHA. The proliferative capacity of DHA-treated OC cells was determined using cell counting kit-8 assay, scratch test and clone formation assay. In addition, OC cells were treated with the ferroptosis inhibitor (ferrostatin-1; Fer-1) in combination with DHA to observe the changes in cell viability. To confirm the oxidative stress-inducing effect of DHA, levels of Fe²⁺, glutathione (GSH) and reactive oxygen species (ROS) were detected using Fe²⁺, GSH and ROS kits, respectively. Western blotting and quantitative PCR analyses were performed to detect the expressions of signal transducer and activator of transcription 3 (STAT3), recombinant solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4) at the protein and gene expression levels to determine stimulatory effects on ferroptosis. In vivo, in accordance with the random number table approach, nude mice with successful tumor loading were divided into vehicle and DHA (150 mg/kg) groups, with 3 mice in each group. Throughout the 10-day treatment period, the body weights and tumor volumes of the mice were documented. The STAT3, SLC7A11, and GPX4 protein expression levels were determined using Western blotting and immunohistochemistry, respectively.

Results: DHA significantly reduced the viability of OC cells, and treatment with Fer-1 significantly increased the survival rate of OC cells (P<0.05 or P<0.01). Subsequent to the administration of DHA, the migration rate and clone formation ability of OC cells decreased significantly (P<0.01). Compared with control cells, DHA-treated OC cells exhibited increased Fe²⁺ and ROS levels (P<0.05 or P<0.01), whereas the GSH level decreased with DHA treatment (P<0.05 or P<0.01). DHA-treated OC cells exhibited significantly lower levels of STAT3, SLC7A11 and GPX4 mRNA and protein than control cells (P<0.05 or P<0.01). In nude mice, treatment with DHA significantly reduced tumor volume (P<0.05). According to Western blotting and immunohistochemistry results, DHA treatment downregulated the expressions of STAT3, SLC7A11, and GPX4 (P<0.05 or P<0.01).

Conclusion: Treatment with DHA can inhibit OC cell proliferation and induce ferroptosis in OC, and these effects may be predominantly mediated via STAT3/GPX4 signaling pathway.