PPARG Activation of Fatty Acid Metabolism Drives Resistance to Anti-HER2 Therapies in HER2-Positive Breast Cancer.

HER2-positive breast cancer, which accounts for approximately 15-20% of all breast cancers, is characterized by its aggressive recurrence, metastasis and reduced survival. Despite advances in anti-HER2 therapies, many patients continue to face treatment resistance, either initially or after an initial positive response, resulting in relapse or disease progression. The primary focus of this research was to identify the peroxisome proliferator-activated receptor gamma (PPARG) as a contributing factor to decreased drug sensitivity by establishing anti-HER2 drug-resistant cell lines of HER2-positive breast cancer. We found that PPARG promotes fatty acid metabolism and activates the PI3K/Akt/mTOR signaling pathway. Inhibition of fatty acid synthesis (FASN) after overexpression of PPARG, effectively blocking the activation of the PI3K/Akt/mTOR pathway and enhancing cellular anti-HER2 drug sensitivity. Co-administration of the PPARG inhibitor GW9662 has emerged as a promising strategy to augment the efficacy of anti-HER2 therapies, offering potential for clinical applications.