Ganoderic acid D attenuates gemcitabine resistance of triple-negative breast cancer cells by inhibiting glycolysis via HIF-1α destabilization.

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Citation abstract

BACKGROUND: Gemcitabine (GEM) resistance is the primary reason why combination chemotherapy is limited in triple-negative breast cancer (TNBC). Ganoderic acid D (GAD), a natural triterpenoid compound obtained from Ganoderma lucidum, has been shown to have antitumor activities. However, whether GAD can reverse GEM resistance in TNBC requires further investigation.

PURPOSE: This study investigated whether and how GAD could reverse GEM resistance in TNBC as an antitumor adjuvant.

METHODS: The effects of GAD on cell proliferation, cell cycle, and glycolysis were studied in vitro using a GEM-resistant (GEM-R) TNBC cell model. We enriched key pathways affected by GAD using proteomics techniques. Western blotting and qPCR were used to detect the expression of glycolysis-related genes after GAD treatment. A mouse resistance model was established using GEM-R TNBC cells, and hematoxylin-eosin staining and immunohistochemistry were used to assess the role of GAD in reversing resistance in vivo.

RESULTS: Cellular functional assays showed that GAD significantly inhibited proliferation and glucose uptake in GEM-R TNBC cells. GAD reduces HIF-1α accumulation in TNBC cells under hypoxic conditions through the ubiquitinated protease degradation pathway. Mechanistically, GAD activates the p53/MDM2 pathway, promoting HIF-1α ubiquitination and proteasomal degradation and downregulating HIF-1α-dependent glycolysis genes like GLUT1, HK2, and PKM2. Notably, GAD combined with gemcitabine significantly reduced the growth of GEM-R TNBC cells in a subcutaneous tumor model.

CONCLUSIONS: This study reveals a novel antitumor function of GAD, which inhibits glycolysis by promoting HIF-1α degradation in GEM-R TNBC cells, offering a promising therapeutic strategy for TNBC patients with GEM resistance.