Shikonin induces ferroptosis in osteosarcomas through the mitochondrial ROS-regulated HIF-1α/HO-1 axis

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Osteosarcoma (OS) is a common malignant bone tumor with poor prognosis and limited treatment options.
• Ferroptosis, an iron-dependent form of regulated cell death, shows promise as an effective therapeutic strategy for OS.
• Shikonin (SHK), a compound from Lithospermum erythrorhizon, exhibits anti-tumor activity, but its role in OS ferroptosis is unclear.

Purpose of the Study:

• To investigate whether Shikonin (SHK) induces ferroptosis in osteosarcoma (OS) cells.
• To elucidate the underlying molecular mechanisms of SHK-induced ferroptosis in OS.

Main Methods:

• Assessed SHK's therapeutic effect on OS cells using cell viability, apoptosis, and cell cycle assays.
• Investigated ferroptosis markers (MDA, GSH/GSSG, ROS, LPO, Fe2+) and key protein expressions (GPX4, SLC7A11) via qRT-PCR and Western blotting.
• Utilized molecular docking, CETSA, and DARTS to evaluate SHK's interaction with HIF-1α; assessed in vivo efficacy in a mouse xenograft model.

Main Results:

• SHK significantly reduced OS cell viability, induced apoptosis, and caused G2/M arrest.
• SHK triggered ferroptosis by increasing intracellular ROS, Fe2+, and lipid peroxidation, while decreasing GSH/GSSG ratio and GPX4/SLC7A11 expression.
• Mitochondrial ROS (MitoROS) promoted HIF-1α expression, leading to HO-1 overexpression and ferroptosis; SHK did not directly bind HIF-1α.

Conclusions:

• The HIF-1α/HO-1 axis, indirectly regulated by MitoROS, is crucial for SHK-induced ferroptosis in osteosarcoma.
• SHK demonstrates potential as an anti-osteosarcoma drug candidate.
• This study identifies novel therapeutic targets for osteosarcoma treatment.