Gene regulation profiles by progesterone and dexamethasone in human endometrial cancer Ishikawa H cells
ABSTRACT Progesterone and glucocorticoids such as dexamethasone mediate distinct biological functions, yet they bind to receptors that recognize the same consensus DNA response element. In breast cancer, progestins are associated with the incidence and progression of tumors, whereas glucocorticoids are growth-suppressive in mammary cancer cells; the differential effects of these two steroids are less well understood in the hormone-dependent disease cancer of the uterine endometrium. We set out to identify genes that are regulated by progesterone through progesterone receptors and dexamethasone through glucocorticoid receptors in a well-differentiated human endometrial cancer cell line.
PR- and GR-positive Ishikawa H endometrial cancer cells were treated with vehicle, dexamethasone (100 nM) or progesterone (100 nM) for 2 h, 6 h, 12 h and 24 h, and RNA was isolated. Affymetrix microarrays were performed using the human HG-U133A chip, querying the expression of 22,000 genes. Expression of genes of particular interest was confirmed by real-time RT-PCR.
Expression analysis demonstrated that dexamethasone and progesterone regulate overlapping but distinct sets of genes and presumably exert many similar but also unique biological effects. Using real-time RT-PCR, we confirmed three particular genes of interest: the transcript for cysteine 1 (legumain), a gene associated with metastasis, that is strongly downregulated by progesterone, upstream c-fos relating transcription factor-2 (USF-2), an anti-proliferative factor that is induced by both progesterone and dexamethasone and N-cadherin, a cellular adhesion molecule downregulated by dexamethasone.
These studies provide new insight into the effects of progesterone and dexamethasone in endometrial cancer cells and provide an extensive list of regulated pathways which can be assessed in the future as biomarkers and molecular targets for new therapies. Taken together, our findings indicate that progesterone and dexamethasone are primarily growth inhibitors in Ishikawa H endometrial cancer cells.
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ABSTRACT: Overexpression of human epidermal growth factor receptor (HER-2) occurs in 20-30% of breast cancers and confers survival and proliferative advantages on the tumour cells making HER-2 an ideal therapeutic target for drugs like Herceptin. Continued delineation of tumour biology has identified splice variants of HER-2, with contrasting roles in tumour cell biology. For example, the splice variant Δ16HER-2 (results from exon 16 skipping) increases transformation of cancer cells and is associated with treatment resistance; conversely, Herstatin (results from intron 8 retention) and p100 (results from intron 15 retention) inhibit tumour cell proliferation. This review focuses on the potential clinical implications of the expression and coexistence of HER-2 splice variants in cancer cells in relation to breast cancer progression and drug resistance. "Individualised" strategies currently guide breast cancer management; in accordance, HER-2 splice variants may prove valuable as future prognostic and predictive factors, as well as potential therapeutic targets.International Journal of Cell Biology 07/2013; 2013:973584. DOI:10.1155/2013/973584
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ABSTRACT: Increasing incidents of disorders such as obesity/diabetes/metabolic syndrome, reproductive dysfunction, and neuro-developmental abnormalities in some human populations have raised concern that disruption of key endocrine-signaling pathways by exposure to environmental chemicals may be involved. This Detailed Review Paper describes some endocrine pathways that have been shown to be susceptible to environmental endocrine disruption and whose disruption could contribute to increasing incidents of some disorders in humans and wildlife populations. Assays and endpoints are described that could be used in new or existing Organization for Economic Cooperative Development (OECD) Test Guidelines for evaluating chemicals for endocrine-disrupting activity. Endocrine pathways evaluated were the hypothalamus:pituitary:adrenocortical (HPA) axis, the hypothalamus:pituitary:gonad (HPG) axis, the somatotropic axis, the retinoid signaling pathway, the hypothalamus:pituitary:thyroid (HPT) axis, the vitamin D signaling pathway, and the peroxisome proliferator-activated receptor (PPAR) signaling pathway. In addition, the potential role of chemical-induced epigenetic modifications to endocrine signaling pathways, during sensitive windows of exposure, was evaluated as a mechanism of endocrine disruption, along with the examination of potential methods for assessing such disruption. This section is provided as an annex to the document (Annex 1). Potential targets of disruption along putative adverse outcome pathways associated with the signaling pathways were identified, along with assays that show promise in evaluating the target in a screening and testing program. Disruption of the HPA or retinoid X receptor signaling pathways could contribute to disorders of emerging concern, and adverse outcome pathways are well defined. However, assays for the assessment of disruption of these pathways are less well developed, and in some cases, are not specific to the pathway. Several new assays were described for the detection of disruption of the HPT axis. These assays may complement assays in the existing Test Guidelines and strengthen the adverse outcome pathway lineage. Assays for the detection of vitamin D signaling disruption and novel aspects of the HPG axis (membrane receptor signaling, progestin signaling) require further development and refinement prior to consideration for incorporation into Test Guidelines. Disruption of the somatotropic axis is likely to occur through disruption of other signaling pathways that cross-talk with the somatotropic axis. Disruption of the somatotropic axis may thus provide a more holistic view of the general integrity of the endocrine system. PPARs are involved in lipid and glucose homeostasis, inflammation, and aspects of development. The adverse outcome pathway for PPARγ is well established. Assays used to assess disruption of PPAR signaling are well developed, and many are suitable for incorporation into existing OECD Test Guidelines. In conclusion, OECD Test Guidelines could be modified to include new assays or the incorporation of novel endpoints into existing assays that would expand the repertoire of endocrine signaling pathways included in the screening and testing regimen
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ABSTRACT: Endometrial cancer, the most common gynecologic malignancy in the United States, is on the rise, and survival is worse today than 40 years ago. In order to improve the outcomes, better biomarkers that direct the choice of therapy are urgently needed. In this review, we explore the estrogen receptor as the most studied biomarker and the best predictor for response for endometrial cancer reported to date.Obstetrics and Gynecology International 10/2013; 2013:479541. DOI:10.1155/2013/479541