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Epidemiological evidence indicates that phytoestrogens inhibit cancer formation and growth, reduce cholesterol levels, and show benefits in treating osteoporosis. At least some of these activities are mediated through the interaction of phytoestrogens with estrogen receptors alpha and beta (ERalpha and ERbeta). Resveratrol, trans-3,5,4'-trihydroxystilbene, is a phytoestrogen in grapes that is present in red wine. Resveratrol was shown to bind ER in cytosolic extracts from MCF-7 and rat uteri. However, the contribution of ERalpha vs. ERbeta in this binding is unknown. Here we report that resveratrol binds ERbeta and ERalpha with comparable affinity, but with 7,000-fold lower affinity than estradiol (E2). Thus, resveratrol differs from other phytoestrogens that bind ERbeta with higher affinity than ERalpha. Resveratrol acts as an estrogen agonist and stimulates ERE-driven reporter gene activity in CHO-K1 cells expressing either ERalpha or ERbeta. The estrogen agonist activity of resveratrol depends on the ERE sequence and the type of ER. Resveratrol-liganded ERbeta has higher transcriptional activity than E2-liganded ERbeta at a single palindromic ERE. This indicates that those tissues that uniquely express ERbeta or that express higher levels of ERbeta than ERalpha may be more sensitive to resveratrol's estrogen agonist activity. For the natural, imperfect EREs from the human c-fos, pS2, and progesterone receptor (PR) genes, resveratrol shows activity comparable to that induced by E2. We report that resveratrol exhibits E2 antagonist activity for ERalpha with select EREs. In contrast, resveratrol shows no E2 antagonist activity with ERbeta. These data indicate that resveratrol differentially affects the transcriptional activity of ERalpha and ERbeta in an ERE sequence-dependent manner.

Dehydroepiandrosterone (3β-hydroxy-5-androsten-17-one, DHEA), secreted by the adrenal cortex, gastrointestinal tract, gonads, and brain, and its sulfated metabolite DHEA-S are the most abundant endogeneous circulating steroid hormones. DHEA actions are classically associated with age-related changes in cardiovascular tissues, female fertility, metabolism, and neuronal/CNS functions. Early work on DHEA action focused on the metabolism to more potent sex hormones, testosterone and estradiol, and the subsequent effect on the activation of the androgen and estrogen steroid receptors. However, it is now clear that DHEA and DHEA-S act directly as ligands for many hepatic nuclear receptors and G-protein-coupled receptors. In addition, it can function to mediate acute cell signaling pathways. This review summarizes the molecular mechanisms by which DHEA acts in cells and animal models with a focus on the 'novel' and physiological modes of DHEA action.

Abstract:The human genome is 'pervasively transcribed' leading to a complex array of noncoding RNAs (ncRNAs) that far outnumber coding mRNAs. ncRNAs have regulatory roles in transcription and post-transcriptional processes as well numerous cellular functions that remain to be fully described. Best characterized of the 'expanding universe' of ncRNAs are the ~ 22 nucleotide microRNAs (miRNAs) that base-pair to target mRNA's 3' untranslated region within the RNA-induced silencing complex (RISC) and block translation and may stimulate mRNA transcript degradation. Long non-coding RNAs (lncRNAs) are classified as >200 nucleotides in length, but range up to several kb and are heterogeneous in genomic origin and function.LncRNAs fold into structures that interact with DNA, RNA, and proteins to regulate chromatin dynamics, protein complex assembly, transcription, telomere biology, and splicing. Some lncRNAs act as sponges for miRNAs and decoys for proteins. Nuclear-encoded lncRNAs can be taken up by mitochondria and lncRNAs are transcribed from mtDNA. Both miRNAs and lncRNAs are dysregulated in endocrine cancers. This review provides an overview on the current understanding of the regulation and function of selected lncRNAs and miRNAs, and their interaction, in endocrine-related cancers: breast, prostate, endometrial, and thyroid.