1. Entinostat as a combinatorial therapeutic for rhabdomyosarcoma.
- Author
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Chauhan, Shefali, Lian, Emily, Habib, Iman, Liu, Qianqian, Anders, Nicole, Bugg, Megan, Federman, Noah, Reid, Joel, Stewart, Clinton, Cates, Tristan, Michalek, Joel, and Keller, Charles
- Subjects
Alveolar rhabdomyosarcoma ,Embryonal rhabdomyosarcoma ,Entinostat ,HDAC inhibitor ,Mocetinostat ,Rhabdomyosarcoma ,Humans ,Pyridines ,Animals ,Benzamides ,Mice ,Rhabdomyosarcoma ,Xenograft Model Antitumor Assays ,Cell Line ,Tumor ,Histone Deacetylase Inhibitors ,Antineoplastic Combined Chemotherapy Protocols - Abstract
Rhabdomyosarcoma (RMS) is the most common childhood soft tissue sarcoma. For the alveolar subtype (ARMS), the presence of the PAX3::FOXO1 fusion gene and/or metastases are strong predictors of poor outcome. Metastatic PAX3::FOXO1+ ARMS often responds to chemotherapies initially, only to subsequently relapse and become resistant with most patients failing to survive beyond 8 years post-diagnosis. No curative intent phase II or phase III clinical trial has been available for patients in the past 10 years (ARST0921). Thus, metastatic ARMS represents a significantly unmet clinical need. Chemotherapy resistance in ARMS has previously been attributed to PAX3::FOXO1-mediated cell cycle checkpoint adaptation, which is mediated by an HDAC3-SMARCA4-miR-27a-PAX3::FOXO1 circuit that can be disrupted by HDAC3 inhibition. In this study, we investigated the therapeutic efficacy of combining the epigenetic regulator entinostat, a Class I Histone Deacetylase (HDAC1-3) inhibitor, with RMS-specific chemotherapies in patient derived xenograft (PDX) models of RMS. We identified single agent, additive or synergistic relationships between relapse-specific chemotherapies and clinically relevant drug exposures of entinostat in three PAX3::FOXO1+ ARMS mouse models. This preclinical data provides further rationale for clinical investigation of entinostat, already known to be well tolerated in a pediatric phase I clinical trial (ADVL1513).
- Published
- 2024