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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atropurosides A-G (1-7), seven new steroidal saponins, which possess new polyhydroxylated aglycones, were isolated from the rhizomes of Smilacina atropurpurea (Convallariaceae), together with a known saponin, dioscin (8). Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1D and 2D NMR techniques and chemical methods. Antifungal testing of the eight compounds indicated that atropurosides B (2) and F (6) were fungicidal against Candida albicans, Candida glabrata, Cryptococcus neoformans, and Aspergillus fumigatus with minimum fungicidal concentrations (MFCs) < or = 20 microg/ml, while dioscin (8) was selectively active against C. albicans and C. glabrata (MFC < or = 5.0 microg/ml). Furthermore, the antifungal saponins 2, 6, and 8 were evaluated for their in vitro cytotoxicities in a panel of human cancer cell lines (SK-MEL, KB, BT-549, SK-OV-3, and HepG2) and non-cancerous Vero cells. All showed moderate cytotoxicities. It appears that the antifungal activity of these steroidal saponins correlates with their cytotoxicity against mammalian cells.
Steroids 2006 Aug
PMID:Atropurosides A-G, new steroidal saponins from Smilacina atropurpurea. 1676 7

Immunosuppression with rapid discontinuation of corticosteroids, usually with induction therapy, is safe in kidney transplant recipients. In 89 patients, we induced immunosuppression with basiliximab or rabbit antithymocyte globulin (17 and 72 patients, respectively). Selection criteria for basiliximab were age (>or=65 years), history (malignancy; chronic infection), and type 1 diabetes mellitus (eligible for pancreas transplant). Steroids were administered through posttransplantation day 4 (five doses); maintenance immunosuppression was with tacrolimus and mycophenolate mofetil. At last follow-up (average, 286 days), most patients were steroid-free (antithymocyte globulin, 90%; basiliximab, 88%). Protocol biopsies were performed at 1, 4, and 12 months posttransplantation. The overall risk of biopsy-proven acute rejection was 12%. At 6 months posttransplantation, acute rejection-free survival was 93% for antithymocyte globulin, 65% for basiliximab (P<.001). Median time to biopsy-proven acute rejection was 27 and 71 days, respectively. The low incidence of biopsy-proven acute rejection with steroid-avoidance immunosuppression may be further reduced with antithymocyte globulin.
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PMID:Acute rejection risk in kidney transplant recipients on steroid-avoidance immunosuppression receiving induction with either antithymocyte globulin or basiliximab. 1679 89

Corticosteroids have always played a valuable role in transplantation. Unfortunately, they are subject to a wide range of side effects, such as hyperlipidemia, hypertension, diabetes mellitus, osteoporosis, growth retardation and Cushingoid appearance. Steroids may also exacerbate problems that existed before surgery, including malignancy, hepatitis B and hepatitis C. New, powerful immunosuppressants have allowed steroid use to be reduced or avoided altogether, but use of these regimens is not simple and may be associated with late acute rejection and recurrence of autoimmune disease. The present review examines the rationale for steroid avoidance in liver transplantation and assesses the new regimens that are currently being developed.
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PMID:Steroid avoidance in liver transplantation. 1680 21

Malignancies are an important cause of morbidity and mortality among transplant patients. Tumor genesis is the consequence of non-specific immunosuppression that enhanced oncogenic virus replication, but may also be due to direct effects of immunosuppressants. Steroids are believed not to be involved in cancer genesis, in contrast to azathioprine, well known to reduce DNA repair ability, particularly in skin cells exposed to UV irradiation. Calcineurin inhibitors, cyclosporine and tacrolimus, are involved in tumor development through various mechanisms: they promote B-cell proliferation by increasing T lymphocyte IL6 secretion, decrease DNA repair ability and may be able to promote metastasis spreading by a direct cellular effect that is independent of their effect on the host's immune cells. In vitro anti-tumoral properties of mycophenolate mofetil have not been valided in animal models or in human. The last developed immunosuppressant mTOR inhibitors, sirolimus and everolimus, effectively control the proliferation of various tumor cell lines, promote tumor cell apoptosis and inhibit metastatic tumor growth and angiogenesis in in vivo mouse models by affecting VEGF production and effect. If these antitumoral features are confirmed in human, this new immunosuppressive family will offer the unique opportunity to reduce both the incidence of rejection and cancer in organ transplant recipients.
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PMID:[Cancer and immunosuppression: pro- and antitumoral effects of immunosuppressive drugs]. 1689 64

A rapid and efficient synthesis of a series of C2-symmetric 17beta-estradiol homo-dimers is described. The new molecules are linked at position 17alpha of the steroid nucleus with either an alkyl chain or a polyethylene glycol chain. They are made from estrone in only five chemical steps with an overall yield exceeding 30%. The biological activity of these compounds was evaluated in vitro on estrogen dependent and independent (ER+ and ER-) human breast tumor cell lines: MCF-7 and MDA-MB-231. Some of the dimers present selective cytotoxic activity against the ER+ cell line. However, they are not very cytotoxic when compared to the antiestrogen tamoxifen. Unfortunately, they show only weak affinity for the estrogen receptor alpha (ERalpha) and no affinity for the estrogen receptor beta (ERbeta). The new compounds were also tested on human intestinal (HT-29) cancer and on murine skin cancer (B16-F10) cell lines for further biological assessment. Interestingly, the dimers were found to be cytotoxic to the murine skin cancer cell line but were inactive towards the intestinal cancer cell line.
Steroids 2006 Oct
PMID:Synthesis of unique 17beta-estradiol homo-dimers, estrogen receptors binding affinity evaluation and cytocidal activity on breast, intestinal and skin cancer cell lines. 1691 77

In the ovary cortisol-cortisone inter-conversion is catalyzed by the enzyme 11beta-hydroxysteroid dehydrogenase (11beta-HSD). Its role in carcinomas of human ovary is unknown. The majority of ovarian cancers are derived from ovarian surface epithelium and the inflammation caused by successive ovulation seems to a play a role in the development of cancer. Cortisol is known to act as anti-inflammatory agent and its metabolism by type 1 and type 11beta-HSD may control the inflammatory action by cortisol in ovary. We undertook this study to investigate type 2 11beta-HSD activity which functions exclusively oxidative direction, in normal ovarian tissue compared to ovarian epithelial cancer. Ovarian tissue was obtained from patients undergoing hysterectomy for both benign and malignant disease. Tissue was placed immediately on dry ice and subsequently transferred to a freezer where they were maintained at -70 degrees C. NAD dependent 11beta-HSD activity was then determined in this tissue. T-test was performed to determine statistical significance. Mean type 2 enzyme activity was 0.87 +/- 1.65 pmol/min g tissue in normal ovarian tissue versus a mean enzyme activity of 2.96 +/- 1.37 pmol/mim g tissue in from cancer specimens. This difference was statistically significant with a p-value of 0.03. Type 2 1beta-HSD activity in ovarian cancer specimens was significantly higher than enzyme activity measured in normal post-menopausal ovarian tissue. Decreased cortisol levels due type 2 1beta-HSD activity may play a role neoplastic transformation as well as tumor proliferation in ovarian cancer by eliminating anti-inflammatory action of cortisol.
Steroids 2006 Nov
PMID:Type 2 11beta-hydroxysteroid dehydrogenase activity in human ovarian cancer. 1702 49

This article describes the origins and evolution of "antiestrogenic" medicines for the treatment and prevention of breast cancer. Developing drugs that target the estrogen receptor (ER) either directly (tamoxifen) or indirectly (aromatase inhibitors) has improved the prognosis of breast cancer and significantly advanced healthcare. The development of the principles for treatment and the success of the concept, in practice, has become a model for molecular medicine and presaged the current testing of numerous targeted therapies for all forms of cancer. The translational research with tamoxifen to target the ER with the appropriate duration (5 years) of adjuvant therapy has contributed to the falling national death rates from breast cancer. Additionally, exploration of the endocrine pharmacology of tamoxifen and related nonsteroidal antiestrogen (e.g. keoxifene now known as raloxifene) resulted in the laboratory recognition of selective ER modulation and the translation of the concept to use raloxifene for the prevention of osteoporosis and breast cancer. However, the extensive evaluation of tamoxifen treatment revealed small but significant side effects such as endometrial cancer, blood clots and the development of acquired resistance. The solution was to develop drugs that targeted the aromatase enzyme specifically to prevent the conversion of androstenedione to estrone and subsequently estradiol. The successful translational research with the suicide inhibitor 4-hydroxyandrostenedione (known as formestane) pioneered the development of a range of oral aromatase inhibitors that are either suicide inhibitors (exemestane) or competitive inhibitors (letrozole and anastrozole) of the aromatase enzyme. Treatment with aromatase inhibitors is proving effective and is associated with reduction in the incidence of endometrial cancer and blood clots when compared with tamoxifen and there is also limited cross resistance so treatment can be sequential. Current clinical trials are addressing the value of aromatase inhibitors as chemopreventive agents for postmenopausal women.
Steroids 2007 Jan
PMID:Development and evolution of therapies targeted to the estrogen receptor for the treatment and prevention of breast cancer. 1716 90

The functional consequences of changes in membrane lipid composition that coincide with malignant growth are poorly understood. Sufficient data have been acquired from studies of lipid binding proteins, post-translational modifications of signaling proteins, and biochemical inhibition of lipidogenic pathways to indicate that growth and survival pathways might be substantially re-directed by alterations in the lipid content of membranes. Cholesterol and glycosphingolipids segregate into membrane patches that exhibit a liquid-ordered state in comparison to membrane domains containing relatively lower amounts of these classes of lipids. These "lipid raft" structures, which may vary in size and stability in different cell types, both accumulate and exclude signaling proteins and have been implicated in signal transduction through a number of cancer-relevant pathways. In prostate cancer cells, signaling from epidermal growth factor receptor (EGFR) to the serine-threonine kinase Akt1, as well as from IL-6 to STAT3, have been demonstrated to be influenced by experimental interventions that target cholesterol homeostasis. The recent finding that classical steroid hormone receptors also reside in these microdomains, and thus may function within these structures in a signaling capacity independent of their role as nuclear factors, suggests a novel means of cross-talk between receptor tyrosine kinase-derived and steroidogenic signals. Potential points of intersection between components of the EGFR family of receptor tyrosine kinases and androgen receptor signaling pathways, which may be sensitive to disruptions in cholesterol metabolism, are discussed. Understanding the manner in which these pathways converge within cholesterol-rich membranes may present new avenues for therapeutic intervention in hormone-dependent cancers.
Steroids 2007 Feb
PMID:Transit of hormonal and EGF receptor-dependent signals through cholesterol-rich membranes. 1717 42

Thyroid hormone (l-thyroxine, T(4), or 3,5,3'-triiodo-l-thyronine, T(3)) treatment of human papillary and follicular thyroid cancer cell lines resulted in enhanced cell proliferation, measured by proliferating cell nuclear antigen (PCNA). Thyroid hormone also induced activation of the Ras/MAPK (ERK1/2) signal transduction pathway. ERK1/2 activation and cell proliferation caused by thyroid hormone were blocked by an iodothyronine analogue, tetraiodothyroacetic acid (tetrac), that inhibits binding of iodothyronines to the cell surface receptor for thyroid hormone on integrin alphaVbeta3. A MAPK cascade inhibitor at MEK, PD 98059, also blocked hormone-induced cell proliferation. We then assessed the possibility that thyroid hormone is anti-apoptotic. We first established that resveratrol (10 microM), a pro-apoptotic agent in other cancer cells, induced p53-dependent apoptosis and c-fos, c-jun and p21 gene expression in both papillary and follicular thyroid cancer cells. Induction of apoptosis by the stilbene required Ser-15 phosphorylation of p53. Resveratrol-induced gene expression and apoptosis were inhibited more than 50% by physiological concentrations of T(4). T(4) activated MAPK in the absence of resveratrol, caused minimal Ser-15 phosphorylation of p53 and did not affect c-fos, c-jun and p21 mRNA abundance. Thus, plasma membrane-initiated activation of the MAPK cascade by thyroid hormone promotes papillary and follicular thyroid cancer cell proliferation in vitro.
Steroids 2007 Feb
PMID:Thyroid hormone is a MAPK-dependent growth factor for thyroid cancer cells and is anti-apoptotic. 1717 66

Lung cancer is the most common cause of cancer mortality in male and female patients in the US. The etiology of non-small cell lung cancer (NSCLC) is not fully defined, but new data suggest that estrogens and growth factors promote tumor progression. In this work, we confirm that estrogen receptors (ER), both ERalpha and ERbeta, occur in significant proportions of archival NSCLC specimens from the clinic, with receptor expression in tumor cell nuclei and in extranuclear sites. Further, ERalpha in tumor nuclei was present in activated forms as assessed by detection of ER phosphorylation at serines-118 and -167, residues commonly modulated by growth factor receptor as well as steroid signaling. In experiments using small interfering RNA (siRNA) constructs, we find that suppressing expression of either ERalpha or ERbeta elicits a significant reduction in NSCLC cell proliferation in vitro. Estrogen signaling in NSCLC cells may also include steroid receptor coactivators (SRC), as SRC-3 and MNAR/PELP1 are both expressed in several lung cell lines, and both EGF and estradiol elicit serine phosphorylation of SRC-3 in vitro. EGFR and ER also cooperate in promoting early activation of p42/p44 MAP kinase in NSCLC cells. To assess new strategies to block NSCLC growth, we used Faslodex alone and with erlotinib, an EGFR kinase inhibitor. The drug tandem elicited enhanced blockade of the growth of NSCLC xenografts in vivo, and antitumor activity exceeded that of either agent given alone. The potential for use of antiestrogens alone and with growth factor receptor antagonists is now being pursued further in clinical trials.
Steroids 2007 Feb
PMID:Estrogen receptor signaling pathways in human non-small cell lung cancer. 1727 70


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