AMPKα2 attenuates doxorubicin induced ferroptosis by promoting NCOA4 degradation in triple negative breast cancer.

AIMS: Triple negative breast cancer (TNBC) is an aggressive type of breast cancer with limited therapeutic options and frequent chemoresistance. AMPK catalytic α-subunit 2 (AMPKα2) is implicated in development of chemoresistance in various cancers. However, the role of AMPKα2 in doxorubicin (DOX)-resistance in TNBC remains to be investigated.

METHODS

The levels of AMPKα2 in DOX-resistant TNBC was examined by Western blotting. AMPKα2 functions on DOX induced ferroptosis were assessed by lipid peroxidation, intracellular iron, MDA, and GSH detection assays. Western blotting, qRT-PCR, co-IP, immunofluorescence staining and KFERQ-mCherry reporter assay were performed to demonstrate the role of AMPKα2 and its association with NCOA4 degradation.

RESULTS

AMPKα2, rather than AMPKα1, was upregulated in DOX-resistant TNBC cells. AMPKα2 inhibited DOX-induced ferroptosis by suppressing NCOA4. AMPKα2 phosphorylated NCOA4 at S151, which enhanced the recognition of NCOA4 by HSC70, and the formation of NCOA4/HSC70/LAMP-2A complex to initiate CMA pathway mediated NCOA4 degradation. S151A mutation or AMPKα inhibitor abolished these biological effects and increased the vulnerability to DOX-induced ferroptosis.

CONCLUSIONS

AMPKα2 suppressed DOX-induced ferroptosis through phosphorylating NCOA4 at S151 to induce its CMA pathway dependent degradation. Targeting AMPKα2 could be a potential strategy to overcome DOX resistance in TNBC patients.