ACSL1 suppresses breast cancer progression by activating ASK1/JNK pathway-mediated autophagy-dependent ferroptosis.

Background

ACSL1, a critical enzyme involved in fatty acid activation and oxidation, has been associated with several malignancies; however, its specific function in breast cancer remains a subject of debate.

Objective

We sought to identify how ACSL1 operates biologically in breast cancer and to elucidate its modulatory effects on autophagy and ferroptosis.

Methods

Analysis of ACSL1 expression in breast cancer was conducted using RNA sequencing, bioinformatics tools (GEPIA), and western blotting. In vitro experiments were carried out using MCF-7 and CAL-51 cells overexpressing ACSL1, either alone or following exposure to the autophagy inhibitor (3-Methyladenine, 3-MA) or ASK1/JNK cascade (GS-4997). Autophagic activity was assessed by visualizing LC3 puncta via immunofluorescence. Ferroptosis was evaluated by measuring intracellular Fe2+ levels with a commercial kit, and oxidative breakdown of lipids was analyzed by C11-BODIPY-based fluorescence detection in conjunction with corresponding assay kits. In vivo, a xenograft model of breast cancer was employed to assess tumor growth, histopathological changes, and ASK1/JNK pathway activation.

Results

Decreased levels of ACSL1 were observed in breast cancer tissues. Ectopic expression of ACSL1 enhanced autophagic activity and triggered ferroptosis. Mechanistically, ACSL1 was found to activate the ASK1/JNK signaling axis, and pharmacological inhibition with GS-4997 abolished ACSL1-induced autophagy and ferroptosis. In vivo, overexpression of ACSL1 reduced tumor growth, suppressed proliferation, increased apoptosis, and enhanced autophagic activity, iron accumulation, and ASK1/JNK activation.

Conclusions

By activating ASK1/JNK pathway-driven, autophagy-dependent ferroptosis, ACSL1 exerts a tumor-suppressive role in breast cancer, underscoring its promise as a therapeutic target.