– TTC352 is a synthetic selective estrogen mimic acts as estrogen receptor (ER) partial agonist for the treatment of endocrine-resistant breast cancer.TTC 352 yields an H-bond with Glu353, allows Asp351-to-helix 12 (H12) interaction, sealing ER?’s ligand-binding domain, recruiting E2-enriched coactivators, and triggering rapid ER?-induced unfolded protein response (UPR) and apoptosis.TTC-352 is a less potent full estrogen agonist compared to E2, allowing H12 to seal the LBD, which recruits many E2-enriched coactivators, and induces rapid ER?-mediated UPR and apoptosis.