20.500.12556/RUL-184373 Targeting steroid-metabolizing enzymes with 15β-substituted estrone analogues dual discovery of AKR1C2/17β-HSD1 inhibitors and a fluorescent 17β-HSD1 ligand Background/objectives: Aldo-keto reductase isoforms AKR1C1-3 and 17β-hydroxysteroid dehydrogenase 1 and 2 (17β-HSD1 and 17β-HSD2) are key enzymes in steroid metabolism and validated targets in hormone-dependent cancers. Methods: In this study, Δ15- and 15β-substituted estrone derivatives were evaluated as inhibitors of AKR1C1-3 and 17β-HSD1 using enzymatic assays, cell viability assaysand computational modeling. Cellular uptake of the fluorescent estrone-based inhibitor was investigated using confocal microscopy. Results: The Δ15-estrone derivative showed potent and selective inhibition of 17β-HSD1 in the low nanomolar range, while 15β-O-propargyl and 15β-azide derivatives exhibited dual inhibitory activity against 17β-HSD1 and AKR1C2. The Δ15- and 15β-azide derivatives reduced cell viability in hormone-dependent breast, endometrial, and ovarian cancer cell lines in the sub- to low-micromolar range. A BODIPY-labeled 15β-O-propargyl analogue retained submicromolar inhibitory potency toward 17β-HSD1, representing the first fluorescent estrane-based inhibitor with preserved biological activity. Confocal microscopy confirmed efficient cellular uptake and predominant cytosolic localization in MCF-7 cells. Conclusions: These findings identify Δ15- and 15β-modified estrone derivatives as promising single- and dual-target inhibitors and introduce a fluorescent probe suitable for investigating intracellular steroid metabolism in hormone-dependent malignancies. 17β-HSD1 enzyme AKR1C1–3 enzymes antiproliferative chemoresistance fluorescent labeling inhibitor encim 17β-HSD1 encimi AKR1C1–3 antiproliferativen kemorezistenca fluorescenčno označevanje inhibitor true false true Angleški jezik Slovenski jezik Članek v reviji 2026-07-06 10:00:29 2026-07-06 10:00:34 2026-07-22 08:52:51 0000-00-00 00:00:00 2026 0 0 19 str. iss. 12, art. 1889 Vol. 18 Jun. 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 577.2 2072-6694 10.3390/cancers18121889 283168259 RAZ_Resch_Vivien_2026.pdf RAZ_Resch_Vivien_2026.pdf 1 724F58527698C7C870802AC177051134 7fae93e62cfa401109342efcb45b31627599dbddec3a1de7ce1f3107ee68751a e17d63f2-7911-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=237058 https://www.mdpi.com/2072-6694/18/12/1889 1 a75faecc-7910-11f1-9b0d-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=237056 Medicinska fakulteta 0 0 0