Huaier induces lipophagy to promote ferroptosis and chemosensitivity via de-acetylation of PLIN3 in triple-negative breast cancer

Background: Huaier, a traditional Chinese medicinal mushroom, has been shown to have anti-tumor properties in our previous studies. However, its role and underlying mechanisms in regulating doxorubicin (DOX) sensitivity in Triple-Negative Breast Cancer (TNBC) remain unclear.

Purpose: This study investigated whether Huaier could potentiate TNBC cell susceptibility to DOX and explored the associated molecular mechanisms involving lipophagy and Ferroptosis.

Methods: The therapeutic potential of Huaier in combination with DOX was evaluated using in vitro cell viability and colony formation assays and validated in xenograft models in vivo. Ferroptosis and lipophagy were characterized by quantifying ROS, MDA, and GSH, as well as by staining with BODIPY and Lyso-Tracker. Underlying mechanisms were dissected using acetylation spectrum profiling, LC-MS, co-immunoprecipitation (co-IP), and proximity ligation assays (PLA).

Results: Huaier significantly enhances TNBC cell sensitivity to DOX both in vitro and in vivo by triggering lipophagy and Ferroptosis. Acetylation spectrum profiling revealed that Huaier selectively deacetylates Perilipin 3 (PLIN3) at lysine 65 (K65), which was responsible for Huaier's regulatory effects on TNBC lipophagy, Ferroptosis, and DOX sensitivity. Mechanistically, Huaier upregulated histone deacetylase 3 (HDAC3) to de-acetylate PLIN3 at K65. Our data also showed that deacetylation of PLIN3 at K65 increased PLIN3-mediated recruitment of ATG16L1, promoting lipophagy and Ferroptosis, and ultimately improving chemo-sensitivity in TNBC cells.

Conclusion: This study showed that Huaier enhanced DOX sensitivity by deacetylating PLIN3 and subsequently induction of lipophagy and Ferroptosis. These results indicate that Huaier may serve as a promising Adjuvant therapeutic approach to augment chemotherapy efficacy in TNBC.