Pharmacological inhibition of 17ß-hydroxysteroid dehydrogenase impairs human endometrial cancer growth in an orthotopic xenograft mouse model.

Endometrial cancer (EC) is the most common gynaecological tumor in developed countries and its incidence is increasing. Approximately 80% of newly diagnosed EC cases are estrogen-dependent. Type 1 17ß-hydroxysteroid dehydrogenase (17ß-HSD-1) is the enzyme that catalyzes the final step in estrogen biosynthesis by reducing the weak estrogen estrone (E1) to the potent estrogen 17ß-estradiol (E2), and previous studies showed that this enzyme is implicated in the intratumoral E2 generation in EC. In the present study we employed a recently developed orthotopic and estrogen-dependent xenograft mouse model of EC to show that pharmacological inhibition of the 17ß-HSD-1 enzyme inhibits disease development. Tumors were induced in one uterine horn of athymic nude mice by intrauterine injection of the well-differentiated human endometrial adenocarcinoma Ishikawa cell line, modified to express human 17ß-HSD-1 in levels comparable to EC, and the luciferase and green fluorescent protein reporter genes. Controlled estrogen exposure in ovariectomized mice was achieved using subcutaneous MedRod implants that released either the low active estrone (E1) precursor or vehicle. A subgroup of E1 supplemented mice received daily oral gavage of FP4643, a well-characterized 17ß-HSD-1 inhibitor. Bioluminescence imaging (BLI) was used to measure tumor growth non-invasively. At sacrifice, mice receiving E1 and treated with the FP4643 inhibitor showed a significant reduction in tumor growth by approximately 65% compared to mice receiving E1. Tumors exhibited metastatic spread to the peritoneum, to the lymphovascular space (LVI), and to the thoracic cavity. Metastatic spread and LVI invasion were both significantly reduced in the inhibitor-treated group. Transcriptional profiling of tumors indicated that FP4643 treatment reduced the oncogenic potential at the mRNA level. In conclusion, we show that 17ß-HSD-1 inhibition represents a promising novel endocrine treatment for EC.

Mapping mRNA Expression of Glaucoma Genes in the Healthy Mouse Eye.

Purpose/Aim: Many genes have been associated with primary open-angle glaucoma (POAG). Knowing exactly where they are expressed in the eye helps to unravel POAG pathology and to select optimal targets for intervention. We investigated whether RNA in situ hybridization (RNA-ISH) is a convenient technique to obtain detailed pan-ocular expression data of these genes. We tested this for four diverse candidate POAG genes, selected because of unclear ocular distribution (F5 and Dusp1) and relevance for potential new therapies (Tnf, Tgfßr3). Optn, a POAG gene with well-known ocular expression pattern served as control. Methods: We made a list of candidate glaucoma genes reported in genetic studies. A table of their ocular expression at the tissue level was compiled using publicly available microarray data (the ocular tissue database). To add cellular detail we performed RNA-ISH for Optn, Tnf, Tgfßr3, F5, and Dusp1 on eyes of healthy, 2-month-old, pigmented, and albino mice. Results: Expression of the Optn control matched with published immunohistochemistry data. Ocular expression of Tnf was generally low, with patches of higher Tnf expression, superficially in the corneal epithelium. F5 had a restricted expression pattern with high expression in the nonpigmented ciliary body epithelium and moderate expression in the peripapillary region. Tgfßr3 and Dusp1 showed ubiquitous expression. Conclusions: RNA-ISH is a suitable technique to determine the ocular expression pattern of POAG genes, adding meaningful cellular detail to existing microarray expression data. For instance, the high expression of F5 in the nonpigmented ciliary body epithelium suggests a role of this gene in aqueous humor dynamics and intraocular pressure. In addition, the ubiquitous expression of Tgfßr3 has implications for designing TGF-ß-related glaucoma therapies, with respect to side effects. Creating pan-ocular expression maps of POAG genes with RNA-ISH will help to identify POAG pathways in specific cell types and to select targets for drug development.