Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transdermal testosterone (T) delivery represents an effective alternative to injectable androgens. We studied 163 hypogonadal men who applied 5, 7.5, or 10 g AndroGel (T gel) 1% CIII per day for up to 42 months. Efficacy data were presented in 123 subjects considered evaluable. Continuous AndroGel treatment normalized mean serum T and free T levels. Mean serum 5alpha-dihydrotestosterone concentrations and 5alpha-dihydrotestosterone/T ratio slightly increased, mean serum estradiol/T ratio doubled, and mean serum FSH and LH levels were suppressed by T replacement. Sexual function and mood parameters improved rapidly and were maintained throughout T treatment. Lean body mass increased (P = 0.0001) and fat mass decreased (P = 0.0001), and these changes were maintained with treatment but were not accompanied by significant increases in muscle strength. Increases in serum bone markers suggestive of increased bone formation were followed by gradual and progressive increases in bone mineral density more in the spine (P = 0.0001) than the hip (P = 0.0004). Mild local skin irritation occurred in 12 subjects, resulting in discontinuation in only one subject. Except for the anticipated increase in hematocrit and hemoglobin, there were no clinically significant changes in blood counts or biochemistry. In three subjects with elevated serum prostate-specific antigen, prostate biopsies showed cancer. We conclude that continued application of AndroGel resulted in beneficial effects similar to those with injectables and other transdermal preparations. This study was neither placebo controlled nor powered to determine the effects of T treatment on prostate cancer risk. Thus, monitoring for prostatic disease and assessment for erythrocytosis are strongly advised to reduce the risk of adverse events with T treatment of hypogonadal men.
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PMID:Long-term testosterone gel (AndroGel) treatment maintains beneficial effects on sexual function and mood, lean and fat mass, and bone mineral density in hypogonadal men. 1512 25

At present, the management of non-organ confined prostate cancer, whether it is a recurrence or metastasis, continues to evolve based on prostate cancer detection using prostate-specific antigen and the development of medications as alternatives for the classical orchiectomy, which induced irreversible implications for quality of life. Diethylstilbestrol therapy was associated with cardiovascular side-effects; GnRH agonists were able to create a castration level, but again considerable side-effects were described. Combination therapies using antiandrogens and GnRH agonists do not improve survival and have additional toxicity. GnRH antagonists, which also suppress FSH, represent the latest class of agents introduced for hormonal treatment, but phase III studies with survival data are not yet available. In spite of all these achievements, hormonal manipulation has resulted in only modest improvements during recent decades and new targets are needed to improve the clinical outcome. Selectively modifying the androgen receptor is currently one of the most promising developments.
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PMID:Endocrine approaches in the therapy of prostate carcinoma. 1579 Jun

Antagonists act by competitive inhibition of pituitary GnRH receptors for which they have a high affinity with a dose-dependent activity. The inhibition concerns LH but also FSH by inhibiting their secretion for 24 hours. At this time, only three molecules are available. Cetrorelix is mainly used for in vitro fertilization protocols, but research is currently being carried out in benign prostatic hypertrophy. Ganirelix is only used in medically assisted procreation. Abarelix is used in the United States as a monthly "depot" injection for the treatment of prostate cancer resistant to other therapies. Other molecules including orally active antagonists are in the course of clinical evaluation or in preclinical phases. The development of this therapeutic class is hampered by conflicting industrial interests and also by problems of tolerability in particular because of the side effects due to induced histamine release. The current indications in France are therefore limited to Assisted Reproductive Technology, and, recently, prostate cancer pending comparative studies versus agonists. The indications under development are endometriosis, myoma and precocious puberty, fields in which agonists have already been found to be effective. Male contraception seems to have a future however this therapeutic regimen remains very expensive. Finally, in benign prostatic hypertrophy, the antagonists administrated intermittently may be used to rapidly improve urinary flow.
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PMID:[GnRH antagonists: present and future]. 1630 12

Gonadotropin-releasing hormone (GnRH) agonists have become the treatment of choice for locally advanced and metastatic prostate cancer. We report a case of prostate cancer in which this treatment led to severe symptoms of intracranial hypertension due to the concomitant presence of an asymptomatic functional pituitary adenoma. A 70-year-old white man was initially evaluated for a multifocal adenocarcinoma, Gleason score 6 (3+3) with perineural invasion suggesting an extracapsular extension. A conformational external beam radiation (74 Gy) with a concomitant GnRH agonist (leuprolide) was initiated. Almost 10 days after the administration of leuprolide the patient complained of visual disturbance, diplopia and other symptoms of intracranial hypertension. Magnetic resonance imaging (MRI) of the brain demonstrated a large sella mass lesion. To relieve the patient's symptoms, a transsphenoidal subtotal tumorectomy was necessary. The histopathological examination revealed an invasive gonadotroph pituitary adenoma. Two years later, there is no sign of progression either on his prostatic disease (prostate-specific antigen of 0.21 ng/mL) or on his pituitary disease (FSH, 4.7 UI/L, LH, 3.1 UI/L and total testosterone, 627 ng/dL) with values of the hypothalamic-pituitary axis in the normal range. We advocate that a high index of suspicion of pituitary tumor must be considered in any case of intracranial hypertension following the administration of GnRH agonist. Abarelix could have a place in such cases.
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PMID:Discovery of a pituitary adenoma following a gonadotropin-releasing hormone agonist in a patient with prostate cancer. 1664 33

The last decade has seen explosive growth in the therapy of prostate cancer. Three areas of therapeutics are emerging: 1) new compounds with novel uses; 2) available compounds with new applications; and 3) new compounds applied to established indications. The novel compounds target specific receptor sites of cancer pathways and attack cancer cells with less effect on normal tissue. Earlyphase trials with compounds targeting the endothelin-A and EGF receptors have shown encouraging results in hormone-refractory prostate cancer. In addition, the Early Prostate Cancer Trial of over 8000 men is currently underway to determine the benefit of adjuvant androgen ablation with bicalutamide in men with localized prostate cancer. Early results show a significant 42% reduction in the progression of the disease in the bicalutamide treatment arm. Further, in large, phase 3 clinical trials in patients needing androgen ablation, the GnRH antagonist abarelix caused no testosterone surge and demonstrated a significantly more rapid decline in serum testosterone to the castrate level than did an LHRH agonist analogue. Abarelix should thus have application as a monotherapy in patients who need a rapid onset of action or are at high risk of complications from the clinical flare seen with LHRH agonists. Abarelix also uniquely caused a sustained decline in serum FSH levels, which have been shown in vitro to stimulate prostate cancer cell growth. If these favorable effects can be duplicated in patients, abarelix might also offer a survival benefit.
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PMID:Emerging pharmacologic therapies for prostate cancer. 1698 5

Early clinical trials in Mexico with analogs of luteinizing hormone-releasing hormone (LH-RH) also known as gonadotropin releasing hormone (Gn-RH), were reviewed. Extensive clinical studies were carried out at IMSS with agonists of LH-RH, both in men and woman. All subjects responded to LH-RH agonists with a release of LH and FSH, but repeated administration of these analogs, initially aimed at stimulation of fertility (thought to stimulate fertility), was later shown to result in inhibition due to desensitization of pituitary gland and downregulation of LH-RH receptors. Various clinical investigations with LH-RH antagonists were also carried out. This included the first demonstration that LH-RHantagonists can suppress LH and FSH and sex steroid secretion in men and women. Various studies in Mexico with early LH-RH antagonists aimed at the development of new contraceptive methods were reviewed. Modern LH-RH antagonist Cetrorelix was shown to be effective in men and women and useful in treatment of uterine leiomyomas and benign prostatic hyperplasia. Major oncological studies were also carried out with agonist D-Trp6-LH-RH and antagonist Cetrorelix in men with prostate cancer, which demonstrated therapeutic efficacy of both types of analogs. Some endocrine studies with early analogs of somatostatin were also cited and a clinical trial with somatostatin analog vapreotide in patients with relapsed prostate cancer was reviewed. All these studies played a major role in introducing analogs of hypothalamic-releasing hormones into clinical medicine.
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PMID:[History of clinical studies on hypothalamic hormone analogs in Mexico]. 1702 7

The asynchronous secretion of gonadotrope LH and FSH under the control of GnRH is crucial for ovarian cyclicity but the underlying mechanism is not fully resolved. Because prostaglandins (PG) are autocrine regulators in many tissues, we determined whether they have this role in gonadotropes. We first demonstrated that GnRH stimulates PG synthesis by induction of cyclooxygenase-2, via the protein kinase C/c-Src/phosphatidylinositol 3'-kinase/MAPK pathway in the LbetaT2 gonadotrope cell line. We then demonstrated that PGF(2alpha) and PGI2, but not PGE2 inhibited GnRH receptor expression by inhibition of phosphoinositide turnover. PGF(2alpha), but not PGI2 or PGE2, reduced GnRH-induction of LHbeta gene expression, but not the alpha-gonadotropin subunit or the FSHbeta subunit genes. The prostanoid receptors EP1, EP2, FP, and IP were expressed in rat gonadotropes. Incubations of rat pituitaries with PGF(2alpha), but not PGI2 or PGE2, inhibited GnRH-induced LH secretion, whereas the cyclooxygenase inhibitor, indomethacin, stimulated GnRH-induced LH secretion. None of these treatments had any effect on GnRH-induced FSH secretion. The findings have thus elaborated a novel GnRH signaling pathway mediated by PGF(2alpha)-FP and PGI2-IP, which acts through an autocrine/paracrine modality to limit autoregulation of the GnRH receptor and differentially inhibit LH and FSH release. These findings provide a mechanism for asynchronous LH and FSH secretions and suggest the use of combination therapies of GnRH and prostanoid analogs to treat infertility, diseases with unbalanced LH and FSH secretion and in hormone-dependent diseases such as prostatic cancer.
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PMID:Reciprocal cross talk between gonadotropin-releasing hormone (GnRH) and prostaglandin receptors regulates GnRH receptor expression and differential gonadotropin secretion. 1713 45

In a series of in vivo and in vitro experiments, it was shown that membrane disrupting lytic peptides (Hecate, Phor14, or Phor21) conjugated to a 15 amino acid segment of the beta chain of CG or to LHRH were able to target and destroy hormone dependent and independent human prostate cancer xenografts in nude mice. In vitro sensitivity of the cells to the drugs was directly related to LH/CG receptor expression, and pretreatment in vitro or in vivo with estrogens or FSH to enhance LH/CG receptor expression capacity and increased sensitivity to the drugs. Administration of unconjugated Hecate and LHRH was ineffective. Most importantly, all of the lytic peptide-betaCG conjugates tested were highly effective in destroying prostate cancer metastatic cells in lymph nodes, bones and lungs.
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PMID:Conjugates of lytic peptides and LHRH or betaCG target and cause necrosis of prostate cancers and metastases. 1738 61

The aim of this clinical study was to determine whether there is a relationship between total serum testosterone, free testosterone, FSH (Follicle-Stimulating Hormone), LH (Luteinizing Hormone) and serum prostate specific antigen (PSA) levels. We postulated that such a correlation existed then the use of hormone specific reference ranges might enhance the usefullness of PSA concentrations <2.5 ng/mL as a marker for prostate cancer. Prior to digital rectal examination, serum was obtained from all patients between 8.30-10:00 AM for hormone and PSA concentrations. The study was performed on 210 male patients >40 years of age visiting our urology outpatient clinics. PSA was correlated to age (r = 0.23, p = 0.019), but there none between serum testosterone and age. No significant correlation was noted between testosterone or free testosterone and serum PSA levels, and none between serum FSH or LH and PSA. In age specific reference groups (41-49; 50-59; 60-69 years), we found no significant correlation between PSA and hormone concentrations. In this population of eugonadal men with serum PSA values less than 2.5 ng/ml, serum androgens and pituitary hormones do not appear to correlate with serum PSA.
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PMID:Correlation of serum androgens and pituitary hormone levels with serum PSA less than 2.5 ng/ml. 1766 Aug 83

Nur77 belongs to a subfamily of nuclear receptors that includes two other members, Nor-1 and Nurr1. It plays an important role in a number of biological processes, including regulation of signaling functions in the hypothalamo-pituitary-adrenal axis, regulation of thymocyte apoptosis, regulation of steroidogenesis and regulation of tumor cell proliferation and apoptosis. In previous studies, using DNA microarray analysis of the effects of the gonadotropin-releasing hormone (GnRH) on the mouse pituitary gonadotroph cell line LbetaT2, we identified Nur77 as one of the highly regulated immediate early genes involved in this response, with >40-fold upregulation after 1 h of treatment of the cells with the GnRH agonist [D-Ala6GnRH (GnRHA)]. GnRH is a hypothalamic decapeptide that stimulates the secretion and expression of gonadotropins (follicle stimulating hormone, FSH and luteinizing hormone releasing hormone, LH) from anterior pituitary through activation of high affinity receptors present on cell membrane of pituitary gonadotropes. In addition to pituitary, the presence of GnRH high affinity receptors has been reported in various cancers and cancer cell lines. In addition, GnRH and its analogs are clinically used in the treatment of prostate cancer. To elucidate the molecular mechanism involved in regulation of Nur77 by GnRH, we first confirmed upregulation of Nur77 in response to GnRH analog (GnRHA) in LbetaT2 cells. Nur77 mRNA was upregulated within 30 min of GnRHA treatment and returned to nearly basal level after 24 h of treatment. Nur77 protein expression was upregulated after 2 h of treatment and remained steady even after 12 h of treatment. The expression of Nur77 mRNA was induced by GnRHA in a dose-dependent manner. Induction of Nur77 expression was stimulated on treatment of cells with forskolin and 8-Br-cAMP, whereas H-89, a specific inhibitor of PKA pathway significantly inhibited GnRHA-induced Nur77 expression. Treatment of cells with both H-89 and EGTA completely blocked the GnRHA-induced expression of Nur77, indicating that both calcium and cAMP/PKA play an important role in regulation of Nur77 expression by GnRHA. Analysis of the protein kinase C (PKC) signaling pathway using specific inhibitors for PKC, Erk1/2, p38 and JNK demonstrated that these pathways are not involved in GnRHA-induced Nur77 expression. Based on our results, we conclude that activation of protein kinase A is the major mechanism regulating the expression of Nur77 by GnRH which may serve as a down-stream signaling gene to mediate the antitumor effects of GnRH.
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PMID:Protein kinase A serves as a primary pathway in activation of Nur77 expression by gonadotropin-releasing hormone in the LbetaT2 mouse pituitary gonadotroph tumor cell line. 1894 69


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