Estrone‐α‐2‐Deoxy‐Glucoside as a Targeted Therapy for Triple‐Negative Breast Cancer: Aromatase Inhibition and Cytotoxicity

Aromatase inhibitors (AIs) are vital in the treatment of estrogen-dependent breast cancer, especially in postmenopausal women. In this study, a series of steroidal glycosides (SGs) derived from trans-androsterone (tAND), estrone (E1), and estradiol (E2) were synthesized using a one-pot multi-enzyme glycosylation approach and structurally characterized via HPLC, MS, and NMR. Among the synthesized compounds, E1-α-2DG (2b) and E2-α-2DG (3b) demonstrated the most potent aromatase inhibition, with IC₅₀ values of 0.101 ± 0.001 μM and 0.159 ± 0.009 μM, respectively. Molecular docking revealed that these glycosides form key hydrogen bonds with catalytic residues and the heme group of CYP19A1. In vitro cytotoxicity showed that E1-α-2DG selectively inhibited the growth of MCF-7 and MDA-MB-231 breast cancer cells in a dose-dependent manner, with the highest potency observed against triple-negative MDA-MB-231 cells (IC₅₀ = 20.46 ± 2.92 μM), while exhibiting no toxicity toward non-cancerous HEK293 cells. These findings suggest that glycosylation enhances the pharmacological potential of steroidal scaffolds and highlights E1-α-2DG as a promising lead compound for the development of safer, dual-function breast cancer therapies.