Soybean isoflavones attenuate the expression of genes related to endometrial cancer risk

Objective We evaluated whether genistein or estrogen treatment has the same effect when administered immediately or late to rats induced with menopause using ovariectomy. Methods Sixty adult female rats were divided into six treatment groups: GIvehicle immediately after ovariectomy; GIIvehicle 30 days after ovariectomy; GIIIgenistein immediately after ovariectomy; GIVgenistein 30 days after ovariectomy; GVestrogen immediately after ovariectomy; and GVIestrogen 30 days after ovariectomy. All animals were treated for 30 consecutive days. At the end of the treatment, part of the uteri was removed for subsequent histological studies and another part was used to evaluate estrogen receptors 1 and 2, cell proliferation (cyclin A1 and A2, cyclin D1, cyclin-dependent kinase inhibitors 1, 1B and 2, antigen identifi ed by the monoclonal antibody Ki67) and angiogenesis (vascular endothelial growth factor, VEGF-A) gene expression. Results Late treatment after castration in rats resulted in more developed endometrium, enhanced cell proliferation and estrogen-signalling pathways, particularly the cyclin-related genes Ki67 and VEGF-A, compared to early treatment. Interestingly, these same effects were less intense with genistein compared to those induced by estrogen, especially when genistein was administered late.