estrone-sulfate and equilin-sulfate

Steroid hormones and their metabolites are currently undergoing clinical trials as potential therapeutics for traumatic brain injury (TBI). To support this work, it is necessary to develop improved procedures for differentiating isobaric species in this compound class. Equilin sulfate (E-S), estrone sulfate (E1-S), 17α-dihydroequilin sulfate (ADHE-S), and 17β-dihydroequilin sulfate (BDHE-S) are primary constituents in hormone replacement therapies, such as Premarin, which are among pharmaceuticals being investigated for TBI treatment. The latter three compounds are isomers and can be difficult to differentiate in trace analytical determinations. In this work, a systematic study of the fragmentation of ADHE-S, BDHE-S, E1-S, and E-S under different stages of higher order tandem mass spectrometry (MS(n)) and variation of collision energy, allowed optimization of conditions for distinguishing the isomeric structures. For epimeric variants (e.g., ADHE-S versus BDHE-S; α- versus β-stereoisomerization in the C-17 position), differentiation was achieved at MS(4) and fragmentation was demonstrated through MS(5). Computational analysis was performed to further explore differences in the fragmentation pathways due to changes in stereochemistry.

Topics: Computer Simulation; Equilin; Estrogens, Conjugated (USP); Estrone; Humans; Isomerism; Models, Molecular; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

Identification of biomarkers potentially provides prognostic information that can help guide clinical decision-making. Given the relationship between estrogen exposure and endometrial cancer, especially low grade endometrioid carcinoma, we hypothesized that high expression of genes induced by estrogen would identify low risk endometrioid endometrial cancers. cDNA microarray and qRT-PCR verification were used to identify six genes that are highly induced by estrogen in the endometrium. These estrogen-induced biomarkers were quantified in 72 endometrial carcinomas by qRT-PCR. Unsupervised cluster analysis was performed, with expression data correlated to tumor characteristics. Time to recurrence by cluster was analyzed using the Kaplan-Meier method. A receiver operating characteristic (ROC) curve was generated to determine the potential clinical utility of the biomarker panel to predict prognosis. Expression of all genes was higher in endometrioid carcinomas compared to non-endometrioid carcinomas. Unsupervised cluster analysis revealed two distinct groups based on gene expression. The high expression cluster was characterized by lower age, higher BMI, and low grade endometrioid histology. The low expression cluster had a recurrence rate 4.35 times higher than the high expression cluster. ROC analysis allowed for the prediction of stage and grade with a false negative rate of 4.8% based on level of gene expression in endometrioid tumors. We have therefore identified a panel of estrogen-induced genes that have potential utility in predicting endometrial cancer stage and recurrence risk. This proof-of-concept study demonstrates that biomarker analysis may play a role in clinical decision making for the therapy of women with endometrial cancer.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Biomarkers, Tumor; Body Mass Index; Carcinoma, Endometrioid; Cluster Analysis; Endometrial Neoplasms; Equilin; Estrogen Replacement Therapy; Estrogens, Conjugated (USP); Estrone; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genetic Association Studies; Humans; Middle Aged; Neoplasm Proteins; Oligonucleotide Array Sequence Analysis; Prognosis; Randomized Controlled Trials as Topic; Reverse Transcriptase Polymerase Chain Reaction; ROC Curve

The binding of ring B unsaturated equine estrogens, equilin sulfate (EqS), equilin (Eq), and 17 beta-dihydroequilin (17 beta-Eq) with human serum proteins was determined and compared with the binding of estrone sulfate (E1S), estrone (E1), estradiol (E2), testosterone (T), and 5 alpha-dihydrotestosterone (5 alpha-DHT). Undiluted serum or 5% human serum albumin (HSA) was incubated with 3H-labeled steroids at 37 C, then subjected to gel filtration at 4 C. Gel filtration of serum from Premarin-treated postmenopausal women or normal women incubated with Eq, E1, E2, or 5 alpha-DHT showed two peaks of radioactivity associated with proteins with average apparent mol wt of 128,000 and 68,000 and average Stokes radii of 48.6 and 34.9 A. These values correspond to those reported for sex hormone-binding globulin (SHBG) and albumin, respectively. Binding to SHBG and albumin was confirmed by removing SHBG or albumin from the serum with Concanavalin-A Sepharose 4B gel or CM-Affi Gel Blue, respectively. In the case of [3H]EqS and [3H]E1S, binding to SHBG was not detectable, and only a peak of radioactivity associated with albumin was found. However, under these conditions, the binding of estrogens to SHBG in serum from normal men was not detectable. Incubation of the above steroids with 5% HSA followed by gel filtration resulted in a single peak of radioactivity associated with the protein peak. Using ultrafiltration dialysis followed by Scatchard analysis, at least two sets of binding sites were found for the interaction of HSA with EqS or E1S. The high and low affinity binding sites had association constants k1 and k2 of approximately 0.9-1.1 (X 10(5) M-1) and 0.5-0.8 (X 10(4) M-1). In contrast with Eq and E1, only the low affinity binding sites were found (apparent Ka congruent to 1 X 10(4) M-1). The binding constants of some estrogens and androgens to SHBG at 37 C determined by competitive Scatchard analysis using DEAE filter assay and [3H]5 alpha-DHT were 0.15, 0.07, 0.22, 0.29, 2.70, and 4.53 (X 10(9) M-1) for Eq, E1, 17 beta-Eq, E2, T, and 5 alpha-DHT, respectively. These results indicate that the equine estrogens bind to SHBG and albumin in a manner similar to that of E1 and E2, and that the low MCR of EqS reported previously may be due to its binding to albumin.

Topics: Animals; Binding, Competitive; Biological Transport; Blood Proteins; Chromatography, Gel; Dihydrotestosterone; Equilin; Estradiol; Estrogens; Estrone; Female; Horses; Hot Temperature; Humans; Male; Protein Binding; Serum Albumin; Sex Hormone-Binding Globulin; Testosterone