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. Author manuscript; available in PMC: 2011 Dec 1.
Published in final edited form as: Future Oncol. 2011 Feb;7(2):263–283. doi: 10.2217/fon.11.2

Figure 5. Role of acetylation in hormone therapy.

Figure 5

Hormones (e.g., estrogen and androgen) mediate activity through HRs, which regulate the transactivation of various target genes. HRs are maintained in a ligand-binding conformation by the HSP90 chaperone complex. This function is regulated by Ac and HDAC6. Acetylation of HSP90 promotes dissociation with HRs and their subsequent degradation via the proteasome. HRs are further regulated by direct acetylation, in part by the histone acetylase p300. Two types of hormone therapy have been developed to disrupt hormone-mediated signaling. Aromatase inhibitors and ADT inhibit the production of estrogen and androgen, respectively. Tamoxifen and bicalutamide compete with hormones for binding to the estrogen and androgen receptors, respectively. Therefore, combining hormone therapy with a HDAC inhibitor would lead to further perturbation of tumorigenic signaling.

Ac: Acetylation; ADT: Androgen deprivation therapy; HDAC: Histone deacetylase; HR: Hormone receptor.