Effects of new C6-substituted steroidal aromatase inhibitors in hormone-sensitive breast cancer cells: Cell death mechanisms and modulation of estrogen and androgen receptors. Issue 195 (December 2019)

• Record Type: Journal Article
• Authors: Augusto, Tiago V.; Amaral, Cristina; Varela, Carla L.; Bernardo, Fernanda; da Silva, Elisiário Tavares; Roleira, Fernanda F.M.; Costa, Saul; Teixeira, Natércia; Correia-da-Silva, Georgina
• Is Part Of: Journal of steroid biochemistry and molecular biology. Issue 195(2019)
• Publication Date: 2019-12
• Subjects: AR Androgen receptor -- AIs Aromatase inhibitors -- CDX Casodex -- CCCP m-Chlorophenylhydrazone -- DiOC6(3) 33′-Dihexyloxacarbocyanine iodide -- MTT 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide -- E2 Estradiol -- ER Estrogen receptor -- ER+ Estrogen receptor positive -- Exe Exemestane -- ICI Fulvestrant -- HFF-1 Human foreskin fibroblast -- LDH Lactate dehydrogenase -- ΔΨm Mitochondrial transmembrane potential -- MTT 3-(45-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide -- RLU Relative luminescence units -- MFI Mean fluorescence intensity -- PI Propidium iodide -- SAR Structure-activity relationship -- SERDs Selective estrogen receptor downregulators -- SERMs Selective estrogen receptor modulators -- STS Staurosporine -- T Testosterone -- TCA Trichloroacetic acid -- TNTE Tris-NaCl-Triton-EDTA Buffer; Breast cancer -- Aromatase inhibitors -- C6-substituted androstanes -- Anti-Cancer properties -- Aromatase -- Estrogen receptor -- Androgen receptor; Steroid hormones -- Periodicals; Biochemistry -- Periodicals; Hormones -- Periodicals; Molecular Biology -- Periodicals; Hormones stéroïdes -- Périodiques; Steroid hormones; Periodicals; 572.579
• DOI: 10.1016/j.jsbmb.2019.105486
• Languages: English
• ISSNs: 0960-0760

Abstract

Highlights: Discovery of C6-substituted steroidal molecules as potent aromatase inhibitors (AIs) in ER+ breast cancer cells. These AIs present anti-cancer properties in ER+ breast cancer cells. The effects on breast cancer cells are dependent on aromatase and/or ER and/or AR. New structure-activity relationships for C6-substituted steroidal compounds were established. Abstract: Estrogen receptor-positive (ER + ) breast cancers require estrogens for their growth. Aromatase inhibitors (AIs) are considered the first-line therapy for this type of tumours. Despite the well-established clinical benefit of this therapy, the search for novel potent AIs that present higher efficacy and fewer side effects is still demanded. Thus, taking into account the known interactions of the natural substrate, androstenedione, within the aromatase active-site, a range of new steroidal compounds have been designed, synthesized and studied by our group. In this work, it was evaluated in MCF-7aro, an ER + breast cancer cell line that overexpress aromatase, the anti-aromatase efficacy and the biological effects of eight new AIs: 6α-methyl-5α-androst-3-en-17-one (1a), 6α-methyl-3α, 4α-epoxy-5α-androstan-17-one (3a), 6α-methylandrost-4-ene-3, 17-dione (9), 6α-allylandrosta-1, 4-diene-3, 17-dione (13), 6α-allylandrost-4-ene-3, 17-dione (15), 6α-allylandrost-4-en-17-one (17), 6β-hydroxyandrost-4-ene-3, 17-dione (19) and 6α-hydroxyandrost-4-ene-3, 17-dione (20). Their anti-cancer properties were elucidated, as well as, the dependence of their mechanism of action on aromatase inhibition and/or on steroid receptors modulation, such as estrogen and androgen receptors, which are key targets for this type of cancer. Results demonstrate that the studied AIs present high anti-aromatase activity, disrupt MCF-7aro cell cycle progression and induce apoptosis, through the mitochondrial pathway. Compounds 1a, 3a, 9, 13, 15 and 17 exhibited an aromatase-dependent effect on cells and, interestingly, steroids 9 and 13 displayed the ability to decrease aromatase protein levels without affecting CYP19A1 mRNA levels. Furthermore, the effects of compounds 1a, 3a and 15 were dependent on ER and on AR modulation, whereas compounds 9 and 19 were only dependent on AR modulation. From a clinical point of view, these actions can be considered as a therapeutic advantage for this type of tumours. Thus, new promising AIs that impair ER + breast cancer cell growth, by acting on aromatase, and even, on ER and AR were discovered. Furthermore, new insights on the most favourable structural modifications in the steroidal core structure were provided, helping to a more rational drug design of new and potent AIs.