Dr. Xavier Salvatella - Rational optimization of transcription factor activation

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Dr. Xavier Salvatella - Rational optimization of transcription factor activation domains Xavier Salvatella Institute for Research in Biomedicine , Barcelona , Spain Rational optimization of transcription factor activation domains Transcription factors are among the most attractive therapeutic targets but are considered undruggable in part due to the intrinsically disordered nature of their activation domains (1). Here we show that the aromatic character of the activation domain of the androgen receptor, a therapeutic target for castration-resistant prostate cancer, is key for its activity as transcription factor, allowing it to translocate to the nucleus and partition into transcriptional condensates upon activation by androgens. On the basis of our understanding of the interactions stabilizing such condensates and of the structure that the domain adopts upon condensation, we optimized the structure of a small-molecule inhibitor previously identified by phenotypic screening. These compounds had more affinity for their target, inhibited androgen-receptor-dependent transcriptional programs, and had an antitumorigenic effect in models of castration-resistant prostate cancer in cells and in vivo. These results suggest that it is possible to rationally optimize, and potentially even to design, small molecules that target the activation domains of oncogenic transcription factors (2). References 1. Biesaga, M., Frigolé-Vivas, M. & Salvatella, X. Intrinsically disordered proteins and biomolecular condensates as drug targets. Curr. Opin. Chem. Biol. 62, 90–100 (2021). 2. Basu, S. et al. Rational optimization of a transcription factor activation domain inhibitor. Nat. Struct. Mol. Biol. 30, 1958–1969 (2023).