Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MTS1 is a metastasis-associated gene highly expressed in high-metastasis tumors. Here we show that the expression of the suppressor gene p53 protein correlates with mts1 expression. In murine melanoma B16-F1 cells, alpha-melanocyte-stimulating hormone up-regulated mts1 and increased p53 positivity in immunohistochemical tests. In B16-ML8 cells, retinoic acid reduced mts1 expression together with a reduction of p53 positivity. The variation of p53 in association with mts1 gene expression suggests that the mts1 product might interact with and stabilize p53. Taxol-induced aneuploidy increased the proportion of G0G1 phase cells, increased p53 positivity, and down-regulated mts1. This suggests that mts1 transcription may have been negatively regulated, possibly on account of the stabilization of microtubules by taxol. We postulate that the control of G1-S transition by p53 could be due to p53 sequestration by mts1, leading to microtubule depolymerization and signaling entry, into the S phase. Thus, a coordinated function of mts1 and p53 may be involved not only in uncontrolled growth but also in cytoskeletal depolymerization that could lead to cancer invasion.
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PMID:Metastasis-associated mts1 gene expression correlates with increased p53 detection in the B16 murine melanoma. 791 76

A hallmark of sun exposure is increased melanin synthesis by cutaneous melanocytes which protects against photodamage and photocarcinogenesis. Irradiation of human keratinocytes or melanocytes with ultraviolet (UV) rays stimulates the synthesis and release of alpha-melanotropin (alpha-MSH) and adrenocorticotropic hormone (ACTH), which induce cyclic AMP (cAMP) formation and increase the proliferation and melanogenesis of human melanocytes. We report that stimulation of cAMP formation is obligatory for the melanogenic response of cultured normal human melanocytes to UVB radiation. In the absence of cAMP inducers, UVB radiation inhibited, rather than stimulated, melanogenesis. UVB radiation (28 mJ/cm2) arrested melanocytes in the G1 phase of the cell cycle, and concomitant treatment with 0.1 microM alpha-MSH enhanced their proliferation but did not increase the surviving fraction. Irradiation with UVB, with or without alpha-MSH, caused prolonged expression of p53 and p21(waf-1, cip-1), maintained pRB in a hypophosphorylated state, and reduced the expression of Bcl2. However, alpha-MSH allowed UVB-irradiated melanocytes to enter S phase, suggesting that alpha-MSH acts as a mitogen rather than a survival factor, and that overexpression of p53 is mainly a signal for cell death. Our results underscore the importance of the cAMP pathway and its physiological inducers in mediating the response of human melanocytes to UV radiation.
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PMID:Activation of the cyclic AMP pathway by alpha-melanotropin mediates the response of human melanocytes to ultraviolet B radiation. 942 56

Endothelin (ET)-1, alpha-melanocyte stimulating hormone (alpha-melanotropin; alpha-MSH), and basic fibroblast growth factor (bFGF) are keratinocyte-derived factors that interact synergistically to stimulate human melanocyte proliferation. ET-1 has a dose-dependent mitogenic effect on human melanocytes and a biphasic effect on melanogenesis: a stimulatory effect at subnanomolar concentrations, and an inhibitory effect at concentrations equal to or higher than 1 nM. Human melanocytes express ET B receptors. Brief treatment of melanocytes with ET-1 caused up-regulation of alpha-MSH receptor mRNA but did not alter ET B receptor mRNA level. ET-1 modulates the response of human melanocytes to UV rays (UVRs). Treatment of melanocytes with 10 nM ET-1 immediately after exposure to UVRs enabled them to overcome the G1 growth arrest. However, ET-1 did not inhibit p53 accumulation or p21(Waf-1/SDI-1/Cip-1) overexpression, nor did it reverse the hypophosphorylated state of pRb or the reduction in Bcl2 level in irradiated melanocytes. These results substantiate the role of ET-1 as a paracrine regulator that modulates the response of human melanocytes to UVRs.
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PMID:Endothelin-1 is a paracrine growth factor that modulates melanogenesis of human melanocytes and participates in their responses to ultraviolet radiation. 969 Jun 25

Adrenal cortical carcinoma (ACC) is a rare neoplasm that affects all age groups, with a bimodal peak of incidence, in young individuals in the first decade or two of life and in older subjects in the fifth to seventh decades. It may be clinically "functional" with Cushing's syndrome, virilization, or feminization, or it may be "nonfunctional." We report on the case of a 42-yr-old woman who complained of abdominal pain and a large adrenal tumor measuring 20 cm in size. No endocrine symptoms were observed. Laboratory tests showed increased levels of adrenocorticotropic hormone (ACTH), serum cortisol, and urinary free cortisol. Cytohistologic features were typical of ACC. A striking presence of hyaline cytoplasmatic globules was seen in cytologic smears and histologically, being immunoreactive for vimentin, consistent with an intracellular store of intermediate filaments. The tumor showed high proliferative activity (40%) with Ki-67 and negativity for p53, cerbB2, and bcl-2. Although hyaline globules are more frequent in pheochromocytomas and other neoplasms, they may also be present in ACC. These globules may be observed in cytologic smears. Also, the identification and immunohistochemical characterization of these hyaline globules in metastases may be useful in determining the origin of primary occult tumors. Diagn. Cytopathol. 1999;21:394-397.
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PMID:Giant adrenal cortical carcinoma, clinically "nonfunctional": report of a case containing cytoplasmic hyaline globules of vimentin. 1057 70

We report five silent corticotroph carcinomas of the pituitary gland. They represent 0.05% of adenohypophyseal tumors surgically treated at Mayo Clinic during a 20-year period and about 5% of all reported pituitary carcinomas. The patients (three females and two males), ranging in age from 26 to 58 years (mean 39 years, median 35 years) presented with symptoms of mass effect; none had Cushing's disease. All tumors were initially invasive macroadenomas, recurred locally, and metastasized, three outside the central nervous system. The follow-up period ranged from 2 to 23 years (mean 10.6 years). All patients died, four of disseminated tumor and one of myocardial infarction. Histologically, three of the primary lesions were indistinguishable from an ordinary benign adenoma. Two were initially diagnosed as atypical adenomas as they featured nuclear pleomorphism, prominent nucleoli, mitotic activity, high MIB-1 labeling indices, and p53 overexpression. For the purpose of comparison, 17 silent corticotroph adenomas were also investigated. In addition, the clinicopathologic features of the silent carcinomas were compared with those of a meta-analysis of published Cushing's disease-associated pituitary carcinomas. The silent adrenocorticotropin carcinomas showed a propensity for extraneural dissemination and an outcome similar to those of the Cushing's disease-associated carcinomas. The two patients with initial atypical tumors died with metastases outside the central nervous system at 2 and 4 years, whereas the three patients with tumors lacking atypia died 16, 18, and 23 years after initial sellar surgery.
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PMID:Silent corticotroph carcinoma of the adenohypophysis: a report of five cases. 1265 32

Ultraviolet radiation is a well established epidemiologic risk factor for malignant melanoma. This observation has been linked to the relative resistance of normal melanocytes to ultraviolet B (UVB) radiation-induced apoptosis, which consequently leads to accumulation of UVB radiation-induced DNA lesions in melanocytes. Therefore, identification of physiologic factors regulating UVB radiation-induced apoptosis and DNA damage of melanocytes is of utmost biological importance. We show that the neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) blocks UVB radiation-induced apoptosis of normal human melanocytes in vitro. The anti-apoptotic activity of alpha-MSH is not mediated by filtering or by induction of melanin synthesis in melanocytes. alpha-MSH neither leads to changes in the cell cycle distribution nor induces alterations in the expression of the apoptosis-related proteins Bcl(2), Bcl(x), Bax, p53, CD95 (Fas/APO-1), and CD95L (FasL). In contrast, alpha-MSH markedly reduces the formation of UVB radiation-induced DNA damage as demonstrated by reduced amounts of cyclobutane pyrimidine dimers, ultimately leading to reduced apoptosis. The reduction of UV radiation-induced DNA damage by alpha-MSH appears to be related to induction of nucleotide excision repair, because UV radiation-mediated apoptosis was not blocked by alpha-MSH in nucleotide excision repair-deficient fibroblasts. These data, for the first time, demonstrate regulation of UVB radiation-induced apoptosis of human melanocytes by a neuropeptide that is physiologically expressed within the epidermis. Apart from its ability to induce photoprotective melanin synthesis, alpha-MSH appears to exert the capacity to reduce UV radiation-induced DNA damage and, thus, may act as a potent protection factor against the harmful effects of UV radiation on the genomic stability of epidermal cells.
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PMID:alpha-Melanocyte-stimulating hormone protects from ultraviolet radiation-induced apoptosis and DNA damage. 1556 80

UV-induced pigmentation (suntanning) requires induction of alpha-melanocyte-stimulating hormone (alpha-MSH) secretion by keratinocytes. alpha-MSH and other bioactive peptides are cleavage products of pro-opiomelanocortin (POMC). Here we provide biochemical and genetic evidence demonstrating that UV induction of POMC/MSH in skin is directly controlled by p53. Whereas p53 potently stimulates the POMC promoter in response to UV, the absence of p53, as in knockout mice, is associated with absence of the UV-tanning response. The same pathway produces beta-endorphin, another POMC derivative, which potentially contributes to sun-seeking behaviors. Furthermore, several instances of UV-independent pathologic pigmentation are shown to involve p53 "mimicking" the tanning response. p53 thus functions as a sensor/effector for UV pigmentation, which is a nearly constant environmental exposure. Moreover, this pathway is activated in numerous conditions of pathologic pigmentation and thus mimics the tanning response.
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PMID:Central role of p53 in the suntan response and pathologic hyperpigmentation. 1763 Sep 65

Adrenocortical causes of Cushing's syndrome include the following: common cortisol-producing adenomas, which are usually isolated (without associated tumors) and sporadic (without a family history); rare, but often clinically devastating, adrenocortical carcinomas; and a spectrum of adrenocorticotropin-independent, and almost always bilateral, hyperplasias, which are not rare, and are the most recently recognized cause. The majority of benign lesions of the adrenal cortex seem to be linked to abnormalities of the cyclic AMP signaling pathway, whereas cancer is linked to aberrant expression of insulin-like growth factor II, tumor protein p53 and related molecules. In this article, we propose a new clinical classification and nomenclature for the various forms of adrenocorticotropin-independent adrenocortical hyperplasias that is based on their histologic and genetic features. We also review the molecular genetics of adrenocortical tumors, including recent discoveries relating to the role of phosphodiesterase 11A. This is a timely Review because of recent advances in the clinical and molecular understanding of these diseases.
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PMID:Genetics of adrenal tumors associated with Cushing's syndrome: a new classification for bilateral adrenocortical hyperplasias. 1795 16

Despite many efforts, regulation of skin and hair pigmentation is still not fully understood. This article focuses mainly on controversial aspects in pigment cell biology which have emerged over the last decade. The central role of tyrosinase as the key enzyme in initiation of melanogenesis has been closely associated with the 6BH4 dependent phenylalanine hydroxylase (PAH) and tyrosine hydroxylase isoform I (THI) providing evidence for an old concept of the three enzyme theory in the initiation of the pigmentation process. In this context, it is noteworthy that intracellular L-phenylalanine uptake and turnover to L-tyrosine via PAH is vital for substrate supply of THI and tyrosinase. While PAH acts in the cytosol of melanocytes, THI and tyrosinase are sitting side by side in the melanosomal membrane. THI at low pH provides L-3,4-hydroxyphenylalanine L-DOPA which in turn is required for activation of met-tyrosinase. After an intramelanosomal pH change, possibly by the p-protein, has taken place, tyrosinase is subject to control by 6/7BH4 and the proopiomelanocortin (POMC) peptides alpha-MSH melanocyte stimulating hormone and beta-MSH in a receptor independent manner. cAMP is required for the activation of microphthalmia-associated transcription factor to induce expression of tyrosinase, for transcription of THI and for activation of PAH. The redundancy of the cAMP signal is discussed. Finally, we propose a novel mechanism involving H2O2 in the regulation of tyrosinase via p53 through transcription of hepatocyte nuclear factor 1alpha which in turn can also affect the POMC response.
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PMID:Regulation of melanogenesis--controversies and new concepts. 1817 48

Endogenous Cushing syndrome (CS) is caused by excess adrenal glucocorticoid secretion that is adrenocorticotropin (ACTH)-dependent or independent; ACTH-independent adrenocortical causes of CS account for up to 20% of CS in adults, and 15% in children over age 7 years. In younger children, ACTH-independent CS may account for as many as half of the CS cases. In both adults and children, adrenocortical lesions causing CS include the common, isolated and sporadic, solitary cortisol-producing adenoma, the rare adrenocortical cancer, and a spectrum of recently recognized, bilateral hyperplasias (bilateral adrenocortical hyperplasias, BAHs): micronodular adrenal disease and its pigmented variant, primary pigmented nodular adrenocortical disease are mostly genetic processes. Macronodular BAHs, ACTH-independent macronodular hyperplasia or massive macronodular adrenocortical disease are less frequently genetic and almost never present in children (except in McCune-Albright syndrome); they present often with atypical CS in middle-aged or elderly adults. The majority of benign adrenocortical tumors associated with CS are associated with defects of the cAMP signaling pathway, whereas adrenal cancer is linked to aberrant expression of growth factors and germline or somatic mutations of tumor suppressor genes such as TP53. Adrenalectomy is the preferred mode of treatment for all adrenocortical causes of CS.
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PMID:Cushing syndrome caused by adrenocortical tumors and hyperplasias (corticotropin- independent Cushing syndrome). 1849 37


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