1. Epigenetic derepression converts PPARγ into a druggable target in triple-negative and endocrine-resistant breast cancers
- Author
-
Ser Yue Loo, Nicholas L. Syn, Angele Pei-Fern Koh, Janet Cheng-Fei Teng, Amudha Deivasigamani, Tuan Zea Tan, Aye Aye Thike, Shireen Vali, Shweta Kapoor, Xiaoyuan Wang, Jiong Wei Wang, Puay Hoon Tan, George W. Yip, Gautam Sethi, Ruby Yun-Ju Huang, Kam Man Hui, Lingzhi Wang, Boon Cher Goh, and Alan Prem Kumar
- Subjects
Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 ,Cytology ,QH573-671 - Abstract
Abstract Clinical trials repurposing peroxisome proliferator-activated receptor-gamma (PPARγ) agonists as anticancer agents have exhibited lackluster efficacy across a variety of tumor types. Here, we report that increased PPARG expression is associated with a better prognosis but is anticorrelated with histone deacetylase (HDAC) 1 and 2 expressions. We show that HDAC overexpression blunts anti-proliferative and anti-angiogenic responses to PPARγ agonists via transcriptional and post-translational mechanisms, however, these can be neutralized with clinically approved and experimental HDAC inhibitors. Supporting this notion, concomitant treatment with HDAC inhibitors was required to license the tumor-suppressive effects of PPARγ agonists in triple-negative and endocrine-refractory breast cancer cells, and combination therapy also restrained angiogenesis in a tube formation assay. This combination was also synergistic in estrogen receptor-alpha (ERα)–positive cells because HDAC blockade abrogated ERα interference with PPARγ-regulated transcription. Following a pharmacokinetics optimization study, the combination of rosiglitazone and a potent pan-HDAC inhibitor, LBH589, stalled disease progression in a mouse model of triple-negative breast cancer greater than either of the monotherapies, while exhibiting a favorable safety profile. Our findings account for historical observations of de-novo resistance to PPARγ agonist monotherapy and propound a therapeutically cogent intervention against two aggressive breast cancer subtypes.
- Published
- 2021
- Full Text
- View/download PDF