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: The fundamental rationale for the use of microarray-based gene expression profiling to characterize biological samples is based in part on the principle that cells, tissues, and perturbations applied to them can be characterized on the basis of their relative expression of genes and transcripts. Different biological states, cell types, and influences can be distinguished based on transcriptional profiles and the change in the relative levels of different genes and gene groups. This genomic expression profile-based discovery of biological states and effector-actions represents an essential element of a systems-based whole-genome approach to characterizing cells and tissues, and differs from the characterization of individual gene expression changes in isolation from one another, and has the potential to increase knowledge in all fields of biomedicine. The past two decades have seen a paradigm shift in which medical genetics has moved from being a tool of the basic investigator to play a role in the mainstream of medical practice. Identification of genetic causal agents of common endocrine disorders, deciphering underlying molecular pathophysiology of known conditions, development of new predictive tests for genetic abnormalities, and applications in the field of therapeutics are some of the implications of this shift. Endocrine systems, in particular, offer tremendous opportunities for the use of genomic analyses to understand physiological and pathological responses and effectors without being biased to a particular gene or set of genes. Therefore, the responses of diverse and potentially diversely affected systems can be broadly evaluated, constrained only by the limitation that there may be either a primary or secondary impact on transcript abundance. This emerging concept—endocrinomics—thus has the potential to significantly impact the field of endocrine research and clinical practice. However, advancements in the field are also limited by problems in collecting comprehensive datasets, the inherent complexity of multiple interacting systems, genetic variations between individuals, and some cumbersomeness associated with expression profiling technology and data analysis itself. This chapter discusses some of the issues to be considered in the design and analysis of microarray experiments for the characterization of endocrine-regulated systems.
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ABSTRACT: The endogenous glucocorticoid, cortisol, elevates blood glucose and suppresses the immune system. Glucocorticoid (GC) levels rapidly increase in response to physiologic and mental stress, thereby allowing stress adaptation. Unfortunately, the GC response can be excessive, especially under stressful conditions for the organism. The resulting hypercortisolemia is associated with a cluster of symptoms called Cushing's syndrome, a serious and potentially fatal illness involving hyperglycemia, hypertension, osteoporosis, muscle atrophy and fat maldistribution, as well as psychoses and immunosuppresion. Several disease states, such as diabetes and Cushing's, would benefit from blocking the actions of endogenous cortisol. The only glucocorticoid receptor (GR) antagonist available in the clinic is the steroid mifepristone (RU-486), whose primary potency is antigestagenic, making its utility as a GR antagonist limited. This manuscript reviews the current patent literature on selective non-steroidal GR antagonists.Expert Opinion on Therapeutic Patents 01/2007; 17(1):59-81. DOI:10.1517/135437184.108.40.206 · 3.44 Impact Factor
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ABSTRACT: These studies demonstrate how loss of function mutations or downregulation of key tumor suppressors missing from type I and type II endometrial cancer cells contributes to carcinogenesis and to resistance to the EGFR inhibitor gefitinib (ZD1839). Cell models devoid of tumor suppressors PTEN and RB1 or PTEN were studied. PTEN, RB1 and p53 expression was reinstated, and the effects on cell cycle, apoptosis, and cell cycle regulators were evaluated. In Ishikawa H cells that model type I endometrial cancer in the loss of PTEN and RB1, re-expressing PTEN and RB1 increased the apoptotic and G1 phases and decreased the S and G2-M phases, which further sensitize the cells to gefitinib. Expressing p53 in Hec50co that model type II tumors by loss of this tumor suppressor arrested cells at the G1-S checkpoint, and apoptosis was also induced. Yet this did not improve sensitivity to gefitinib. Modulation of the cell cycle regulators responsible for these changes is explored, and a potential new therapeutic target, MDM2, is identified. The downregulation of p53 expression in type II Hec50co cells is linked to gefitinib resistance. In addition, the overexpression of MDM2, the principal factor that inhibits p53 function also occurs in these resistant cells. MDM2 phosphorylation is only partially blocked by gefitinib, and high MDM2 expression may relate to drug resistance.Gynecologic Oncology 08/2007; 106(1):94-104. DOI:10.1016/j.ygyno.2007.03.006 · 3.69 Impact Factor