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Bulletin Du Cancer Oct 1999Aromatase inhibitors used in breast cancer, are drugs that inhibit the transformation of androstenedione and testosterone, respectively in estradiol and estrone. Two... (Review)
Review
Aromatase inhibitors used in breast cancer, are drugs that inhibit the transformation of androstenedione and testosterone, respectively in estradiol and estrone. Two classes have been described: steroidal inhibitors which act competitively and irreversibly and non steroidal inhibitors which block the P 450 cytochrome. The first one is aminoglutethimide which has an adrenal effect on 11, 18 and 21 hydroxylase. Rogletimide, less powerful and less specific is a aminoglutethimide analogue. The response rates obtained with formestane is not different. The clinical development has been stopped due to a lack of specificity. Letrozole, vorozole, exemestane and anastrozole are more powerful and more specific. Letrozole and vorozole are at least as efficient and better tolerated than aminoglutéthimide. Anastrozole, letrozole and vorozole are at least as efficient as megestrol acetate and better tolerated in advanced breast cancer patients receiving a second line hormone therapy.
Topics: Aminoglutethimide; Anastrozole; Androstadienes; Androstenedione; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Cytochrome P-450 Enzyme Inhibitors; Enzyme Inhibitors; Estrogen Antagonists; Estrone; Female; Humans; Letrozole; Nitriles; Triazoles
PubMed: 10572233
DOI: No ID Found -
Therapeutic Advances in Endocrinology... 2022Cushing's syndrome (CS) is an endocrine disease characterized by excessive adrenocortical steroid production. One of the mainstay pharmacological treatments for CS are... (Review)
Review
Cushing's syndrome (CS) is an endocrine disease characterized by excessive adrenocortical steroid production. One of the mainstay pharmacological treatments for CS are steroidogenesis enzyme inhibitors, including the antifungal agent ketoconazole along with metyrapone, mitotane, and aminoglutethimide. Recently, osilodrostat was added to this drug class and approved by the US Food and Drug Administration (FDA) for the treatment of Cushing's Disease. Steroidogenesis enzyme inhibitors inhibit various enzymes along the cortisol biosynthetic pathway and may be used preoperatively to lower cortisol levels and reduce surgical risk associated with tumor resection or postoperatively when surgery and/or radiation therapies are not curative. Because their selectivities for steroidogenic enzymes vary, they may even be administered in combination to achieve relatively rapid control of severe hypercortisolemia. Unfortunately, all currently available inhibitors are accompanied by serious adverse side effects that limit dosing and often result in treatment failures. Although more commonly known as a general anesthetic induction agent, etomidate is another member of the steroidogenesis enzyme inhibitor drug class. It suppresses cortisol production primarily by inhibiting 11β-hydroxylase and is the only inhibitor that may be given parenterally. However, the sedative-hypnotic actions of etomidate limit its use as an acute management option for CS. Thus, some have recommended that it be used only in intensive care settings. In this review, we discuss the initial development of etomidate as an anesthetic agent, its subsequent development as a treatment for CS, and the recent advances in dosing and drug development that dissociate sedative-hypnotic and adrenostatic drug actions to facilitate CS treatment in non-critical care settings.
PubMed: 35186251
DOI: 10.1177/20420188211058583 -
Turkish Journal of Pharmaceutical... Dec 2022Aromatase is an enzyme that catalyzes the conversion of androgens to estrogens. While inhibition of aromatase is a useful approach for treating breast cancer, it may...
OBJECTIVES
Aromatase is an enzyme that catalyzes the conversion of androgens to estrogens. While inhibition of aromatase is a useful approach for treating breast cancer, it may also have toxicological consequences due to its endocrine disrupting/modulating effect. In this study, sensitivity and performance of two assays -a cell free and a cell-based- for evaluating aromatase activity were investigated by testing known aromatase inhibitors and partial validation of the methods was performed. Advantages and disadvantages of these methods are also discussed.
MATERIALS AND METHODS
Aromatase activity was evaluated two models; direct measurement with a cell-free assay using a fluorescent substrate and recombinant human enzyme and indirect evaluation with a cell-based assay where cell proliferation was determined in estrogen receptor positive human breast cancer cells (MCF-7 BUS) in the absence of estrogen and the presence of testosterone.
RESULTS
In the cell-free direct measurement assay, reference compounds ketoconazole and aminoglutethimide have been shown to inhibit the aromatase enzyme with half-maximal inhibitory concentration (IC) values concordant with literature. In cell-based indirect measurement assay, only ketoconazole dose-dependently inhibited cell proliferation with 3.47 x 10 M IC. Inter-assay and intra-assay reproducibility of both methods was found to be within acceptable deviation levels.
CONCLUSION
Both methods can be successfully applied. However, to evaluate the potential aromatase activity of the novel compounds , it seems better to perform both the cell-based and the cell-free assays that allows low-moderate biotransformation and eliminate cytotoxicity potential, respectively.
PubMed: 36544280
DOI: 10.4274/tjps.galenos.2021.85530 -
Breast Cancer Research and Treatment 2007Because estrogen contributes to the promotion and progression of breast cancer, a greater understanding of the role of estrogen in breast cancer has led to therapeutic... (Review)
Review
Because estrogen contributes to the promotion and progression of breast cancer, a greater understanding of the role of estrogen in breast cancer has led to therapeutic strategies targeting estrogen synthesis, the estrogen receptor, and intracellular signaling pathways. The enzyme aromatase catalyses the final step in estrogen biosynthesis and was identified as an attractive target for selective inhibition. Modern third-generation aromatase inhibitors (AIs) effectively block the production of estrogen without exerting effects on other steroidogenic pathways. The discovery of letrozole (Femara) achieved the goal of discovering a highly potent and totally selective AI. Letrozole has greater potency than other AIs, including anastrozole, exemestane, formestane, and aminoglutethimide. Moreover, letrozole produces near complete inhibition of aromatase in peripheral tissues and is associated with greater suppression of estrogen than is achieved with other AIs. The potent anti-tumor effects of letrozole were demonstrated in several animal models. Studies with MCF-7Ca xenografts successfully predicted that letrozole would be clinically superior to the previous gold standard tamoxifen and also indicated that it may be more effective than other AIs. An extensive program of randomized clinical trials has demonstrated the clinical benefits of letrozole across the spectrum of hormone-responsive breast cancer in postmenopausal women.
Topics: Aged; Animals; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Chemotherapy, Adjuvant; Dose-Response Relationship, Drug; Female; Humans; Letrozole; Middle Aged; Molecular Structure; Neoadjuvant Therapy; Neoplasms, Hormone-Dependent; Nitriles; Receptors, Estrogen; Structure-Activity Relationship; Tamoxifen; Treatment Outcome; Triazoles
PubMed: 17912633
DOI: 10.1007/s10549-007-9696-3 -
Tamsulosin facilitates depressive-like behaviors in mice: Involvement of endogenous glucocorticoids.Brain Research Bulletin Jan 2022The benign prostatic hyperplasia (BPH) is the main source of lower urinary tract symptoms. The BPH is a common age-dependent disease and tamsulosin is an α-adrenoceptor...
The benign prostatic hyperplasia (BPH) is the main source of lower urinary tract symptoms. The BPH is a common age-dependent disease and tamsulosin is an α-adrenoceptor blocker widely prescribed for BPH. Beyond the common adverse effects of tamsulosin, increased diagnosis of dementia after prescription was observed. Importantly, a clinical study suggested that tamsulosin may exert antidepressant effects in BPH patients. Considering the expression of α-adrenoceptors in the brain, this study aimed to investigate the effects of tamsulosin in the forced swimming and open field tests in mice. For this, tamsulosin (0.001-1 mg/kg) was orally administered subacutely (1, 5 and 23 hr) and acutely (60 min) before tests. Mifepristone (10 mg/kg), a glucocorticoid receptor antagonist, and aminoglutethimide (10 mg/kg), a streoidogenesis inhibitor, were intraperitoneally injected before tamsulosin to investigate the role of the hypothalamic-pituitary-adrenal axis in the mediation of tamsulosin-induced effects. Subacute and acute administrations of tamsulosin increased the immobility time in the first exposition to an inescapable stressful situation. In the re-exposition to the swim task, controls displayed a natural increase in the immobility time, and the treatment with tamsulosin further increased this behavioral parameter. Tamsuslosin did not affect spontaneous locomotion neither in naïve nor in stressed mice. Our findings also showed that mifepristone and aminoglutethimide prevented the tamsulosin-induced increase in the immobility time in the first and second swimming sessions, respectively. In conclusion, tamsulosin may contribute to increased susceptibility to depressive-like behaviors, by facilitating the acquisition of a passive stress-copying strategy. These effects seem to be dependent on endogenous glucocorticoids.
Topics: Adaptation, Psychological; Adrenergic alpha-1 Receptor Antagonists; Aminoglutethimide; Animals; Aromatase Inhibitors; Behavior, Animal; Depression; Disease Models, Animal; Hormone Antagonists; Hypothalamo-Hypophyseal System; Mice; Mifepristone; Receptors, Glucocorticoid; Tamsulosin
PubMed: 34798218
DOI: 10.1016/j.brainresbull.2021.11.005 -
The Oncologist 2000The large number of excellent presentations on breast cancer at this year's ASCO meeting reflects the enormous interest in clinical trials of this common disease. In the...
The large number of excellent presentations on breast cancer at this year's ASCO meeting reflects the enormous interest in clinical trials of this common disease. In the reports of adjuvant hormonal therapy, the most interesting included Abstract 273 by Boccardo et al., who reported that postmenopausal women with estrogen receptor positive (ER(+)) cancers who had already completed three years of tamoxifen experienced better overall survival if treated with two years of subsequent aminoglutethimide (a first-generation aromatase inhibitor) rather than another two years of tamoxifen. This whets our appetite for studies currently under way to define the role of third-generation aromatase inhibitors in the adjuvant setting. A report by FISHER: from the National Surgical Adjuvant Breast and Bowel Project B-23 study (Abstract 277) provided confirmation of what is rapidly becoming accepted, that the addition of tamoxifen to chemotherapy does not benefit breast cancer patients with negative lymph nodes who have ER(-) cancers. In premenopausal women, another report of the benefit of hormonal therapy, this time by the French Adjuvant Study Group using complete hormonal blockade with a luteinizing hormone-releasing hormone agonist and tamoxifen (Abstract 279) showed that hormonal therapy can be at least as good as, if not better, than six cycles of 5-fluorouracil 500 mg/m(2), epirubicin 50 mg/m(2), cyclophosphamide 500 mg/m(2) in terms of disease-free survival and overall survival. Among the papers on adjuvant chemotherapy, a controversial paper from the German Adjuvant Breast Cancer Group reported that three cycles of CMF (a dose-intense regimen with all three drugs being given on days 1 and 8) were as good as six cycles (Abstract 283). Another report, from the International Breast Cancer Study Group, raised the controversial question of whether there really is much added benefit from the addition of chemotherapy to tamoxifen in postmenopausal women with negative lymph nodes if their tumors have ERs (Abstract 281). A second study (the first was the CALGB study reported at ASCO in 1998) showing a benefit to the addition of Taxol to an anthracycline-based adjuvant regimen, was reported from the M.D. Anderson Cancer Center (Abstract 285), giving further impetus to the inclusion of Taxol in standard adjuvant treatment. Finally, there were a number of interesting presentations on HER-2. Reported here are three of these, all addressing the effect of HER-2 overexpression on the response to hormonal therapy. Taken together, they uphold the emerging concern that women with ER(+) cancers may not benefit significantly from endocrine treatment if the tumors also overexpress HER-2. Observations such as these will afford us the ability to predict more accurately which women will benefit from specific treatments.
Topics: Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Chemotherapy, Adjuvant; Female; Humans; Neoplasm Staging; Prognosis; Receptor, ErbB-2; Receptors, Estrogen; Tamoxifen
PubMed: 10964995
DOI: 10.1634/theoncologist.5-4-285 -
Oncology (Williston Park, N.Y.) Mar 1998Letrozole (Femara) is a nonsteroidal aromatase inhibitor that is approximately 10,000 times as potent as aminoglutethimide in vivo. Two pivotal multinational phase III... (Review)
Review
Letrozole (Femara) is a nonsteroidal aromatase inhibitor that is approximately 10,000 times as potent as aminoglutethimide in vivo. Two pivotal multinational phase III trials have compared letrozole (0.5 and 2.5 mg/d) against megestrol acetate and aminoglutethimide, respectively, in patients with locally advanced or metastatic breast cancer. The letrozole vs megestrol acetate trial showed the superiority of letrozole (2.5 mg/d) over megestrol acetate with respect to response rate, response duration, duration of overall clinical benefit (complete response plus partial response plus stable disease > or = 6 months), time to progression, and time to treatment failure. The letrozole-treated patients also showed a nonsignificant trend toward better survival. In the letrozole vs aminoglutethimide trial, letrozole (2.5 mg/d) was significantly superior in terms of duration of overall clinical benefit and survival. There were also strong trends favoring letrozole with regard to objective response rate and duration of response. Unexpectedly, both trials demonstrated a dose-response effect for 2.5 mg of letrozole over 0.5 mg in terms of response and overall survival. This finding raises the possibility that intratumoral aromatase suppression may be more relevant in breast cancer therapy than are plasma estrogen levels.
Topics: Aminoglutethimide; Antineoplastic Agents; Aromatase Inhibitors; Breast Neoplasms; Clinical Trials as Topic; Disease-Free Survival; Dose-Response Relationship, Drug; Enzyme Inhibitors; Female; Humans; Letrozole; Megestrol Acetate; Nitriles; Treatment Outcome; Triazoles
PubMed: 9556791
DOI: No ID Found -
Brain Research Reviews Mar 2008In the cycling female rat, estradiol and progesterone induce reproductive behavior and the surge of luteinizing hormone (LH) needed for ovulation. Circulating estradiol... (Review)
Review
In the cycling female rat, estradiol and progesterone induce reproductive behavior and the surge of luteinizing hormone (LH) needed for ovulation. Circulating estradiol of ovarian origin induces progesterone receptors in the preoptic area and hypothalamus. Sequential activation of estrogen receptors (ER) and progesterone receptors coordinates reproductive physiology and behavior. In ovariectomized and adrenalectomized (ovx/adx) rats, administration of estradiol alone is sufficient to initiate an LH surge, and central infusion of aminoglutethimide (AGT), a blocker of the P450 side chain cleavage enzyme, disrupted the estrous cycle of intact rats without affecting peripheral estradiol levels, suggesting that an endogenous source of progesterone remains in these animals. In ovx/adx rats, progesterone levels in the hypothalamus increase prior to the LH surge, and inhibition of progesterone synthesis prevents the LH surge, suggesting that hypothalamic neuroprogesterone is necessary for estrogen positive feedback. In support of the idea that estradiol induces neuroprogesterone, estradiol increased expression of the progesterone-synthesizing enzyme 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the hypothalamus before the LH surge. Further, in vitro experiments demonstrate that estradiol stimulates progesterone synthesis in astrocytes, considered to be the most active steroidogenic cells in the CNS. To stimulate neurosteroidogenesis, estradiol acts through membrane ER and type 1a metabotropic glutamate receptors (mGluR1a) to increase free cytoplasmic calcium ([Ca(2+)](i)) via activation of the PLC-IP(3) pathway. Estradiol-induced progesterone synthesis is mimicked by thapsigargin-induced release of IP(3) receptor-sensitive Ca(2+) stores in astrocyte cultures. Thus, estradiol-induced progesterone synthesis is dependent on membrane ERs that act through mGluR1a to activate the PLC-IP(3) pathway. This neuroprogesterone also facilitated proceptive behavior. Blocking either progesterone synthesis or progesterone receptor in estrogen-primed ovx/adx prevented proceptive but not receptive behaviors.
Topics: Animals; Brain; Estrogens; Feedback, Physiological; Female; Humans; Progesterone; Reproduction; Reproductive Behavior; Steroids
PubMed: 17850878
DOI: 10.1016/j.brainresrev.2007.06.009 -
The Cochrane Database of Systematic... Oct 2009Endocrine therapy removes the influence of oestrogen on breast cancer cells and so hormonal treatments such as tamoxifen, megestrol acetate and medroxyprogesterone... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Endocrine therapy removes the influence of oestrogen on breast cancer cells and so hormonal treatments such as tamoxifen, megestrol acetate and medroxyprogesterone acetate have been in use for many years for advanced breast cancer. Aromatase inhibitors (AIs) inhibit oestrogen synthesis in the peripheral tissues and have a similar tumour-regressing effect to other endocrine treatments. Aminoglutethimide was the first AI in clinical use and now the third generation AIs, anastrozole, exemestane and letrozole, are in current use. Randomised trial evidence on response rates and side effects of these drugs is still limited.
OBJECTIVES
To compare AIs to other endocrine therapy in the treatment of advanced breast cancer in postmenopausal women.
SEARCH STRATEGY
For this update, the Cochrane Breast Cancer Group Specialised Register and the Cochrane Central Register of Controlled Trials (CENTRAL) and relevant conference proceedings were searched (to 30 June 2008).
SELECTION CRITERIA
Randomised controlled trials in postmenopausal women comparing the effects of any AI versus other endocrine therapy, no endocrine therapy, or a different AI in the treatment of advanced (metastatic) breast cancer. Non-English language publications, comparisons of the same AI at different doses, AIs used as neoadjuvant treatment, or outcomes not related to tumour response were excluded.
DATA COLLECTION AND ANALYSIS
Data from published trials were extracted independently by two review authors and cross-checked by a third. Hazard ratios (HR) were derived for analysis of time-to-event outcomes (overall and progression-free survival). Odds ratios (OR) were derived for objective response, clinical benefit, and toxicity.
MAIN RESULTS
Thirty-seven trials were identified, 31 of which were included in the main analysis of any AI versus any other treatment (11,403 women). No trials were excluded due to inadequate allocation concealment. The pooled estimate showed a significant survival benefit for treatment with an AI over other endocrine therapies (HR 0.90, 95% CI 0.84 to 0.97). A subgroup analysis of the three commonly prescribed AIs (anastrozole, exemestane, letrozole) also showed a similar survival benefit (HR 0.88, 95% CI 0.80 to 0.96). There were very limited data to compare one AI with a different AI, but these suggested an advantage for letrozole over anastrozole.AIs have a different toxicity profile to other endocrine therapies. For those currently prescribed, and for all AIs combined, they had similar levels of hot flushes and arthralgia; increased risks of rash, nausea, diarrhoea and vomiting; but a 71% decreased risk of vaginal bleeding and 47% decrease in thromboembolic events compared with other endocrine therapies.
AUTHORS' CONCLUSIONS
In women with advanced (metastatic) breast cancer, aromatase inhibitors including those in current clinical use show a survival benefit when compared to other endocrine therapy.
Topics: Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Female; Humans; Neoplasms, Hormone-Dependent; Postmenopause; Randomized Controlled Trials as Topic
PubMed: 19821307
DOI: 10.1002/14651858.CD003370.pub3 -
The Journal of Biological Chemistry Jul 2022Neurosteroids, modulators of neuronal and glial cell functions, are synthesized in the nervous system from cholesterol. In peripheral steroidogenic tissues, cholesterol...
Neurosteroids, modulators of neuronal and glial cell functions, are synthesized in the nervous system from cholesterol. In peripheral steroidogenic tissues, cholesterol is converted to the major steroid precursor pregnenolone by the CYP11A1 enzyme. Although pregnenolone is one of the most abundant neurosteroids in the brain, expression of CYP11A1 is difficult to detect. We found that human glial cells produced pregnenolone, detectable by mass spectrometry and ELISA, despite the absence of observable immunoreactive CYP11A1 protein. Unlike testicular and adrenal cortical cells, pregnenolone production in glial cells was not inhibited by CYP11A1 inhibitors DL-aminoglutethimide and ketoconazole. Furthermore, addition of hydroxycholesterols increased pregnenolone synthesis, suggesting desmolase activity that was not blocked by DL-aminoglutethimide or ketoconazole. We explored three different possibilities for an alternative pathway for glial cell pregnenolone synthesis: (1) regulation by reactive oxygen species, (2) metabolism via a different CYP11A1 isoform, and (3) metabolism via another CYP450 enzyme. First, we found oxidants and antioxidants had no significant effects on pregnenolone synthesis, suggesting it is not regulated by reactive oxygen species. Second, overexpression of CYP11A1 isoform b did not alter synthesis, indicating use of another CYP11A1 isoform is unlikely. Finally, we show nitric oxide and iron chelators deferoxamine and deferiprone significantly inhibited pregnenolone production, indicating involvement of another CYP450 enzyme. Ultimately, knockdown of endoplasmic reticulum cofactor NADPH-cytochrome P450 reductase had no effect, while knockdown of mitochondrial CYP450 cofactor ferredoxin reductase inhibited pregnenolone production. These data suggest that pregnenolone is synthesized by a mitochondrial cytochrome P450 enzyme other than CYP11A1 in human glial cells.
Topics: Aminoglutethimide; Cholesterol; Cholesterol Side-Chain Cleavage Enzyme; Humans; Ketoconazole; Neuroglia; Neurosteroids; Pregnenolone; Reactive Oxygen Species
PubMed: 35688208
DOI: 10.1016/j.jbc.2022.102110