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)

We have developed a dissociated primary cell culture of noradrenergic neurons from the locus ceruleus of postnatal (1- to 5-d-old) mice or rats. Slices of the brain stem were made on a Vibratome. Then the region of locus ceruleus, which was identified by observing the slices under a dissecting microscope, was dissected out from the slices. The removed fragments of brain slices were dissociated and cultured up to 3 weeks on a non-neuronal feeder layer, which consisted predominantly of astroglial cells, or on a fibronectin-treated collagen substratum. After 2 weeks of culture, about 70% of total neuronlike cells revealed positive catecholamine histofluorescence, indicating that they were probably noradrenergic neurons. About 98% of large- and medium-sized cultured neurons (soma diameter greater than or equal to 20 microns) was histofluorescence positive. The fluorescence-positive cells had long processes rich in varicosities, and the shape of their soma was either multipolar or fusiform. Electron microscopy using permanganate fixation revealed that the varicosities along their processes had small granular vesicles, which may contain norepinephrine. Physiological properties of these noradrenergic neurons were investigated with intracellular microelectrodes or with the whole-cell version of the patch clamp. We observed that many cells were producing spontaneous firing. Many of these spontaneously firing cells had no obvious contact with neighboring cells. The neurons were depolarized when glutamate was applied by pressure ejection. They also responded to GABA and glycine with either hyperpolarization or depolarization, and these responses were antagonized by picrotoxin and strychnine. Application of substance P generally produced depolarization with an increase in input resistance. The neurons responded with hyperpolarization to somatostatin, beta-endorphin, and enkephalin. This culture system will become a useful tool for elucidating the cellular and molecular properties of the central noradrenergic neurons.
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PMID:Noradrenergic neurons from the locus ceruleus in dissociated cell culture: culture methods, morphology, and electrophysiology. 243 74

The characteristics of 7 human melanoma cell lines were compared with those of the xenografts from which they were established. The ultrastructure, melanin content, isozyme pattern and chromosome numbers of the cell lines were closely similar to those of the corresponding xenografts. The different cell lines gave rise to colonies in soft agar of size and morphology similar to the parent xenografts, and the plating efficiencies were clearly correlated. However, no correlation was found between the growth rates in vivo and either the doubling times and saturation densities in monolayer cultures or the plating efficiencies in soft agar. Moreover, one of the cell lines lost its tumorigenic ability upon establishment in culture. Thus, although the properties of the cell lines by and large reflected those of the parent xenografts, important inconsistencies were seen. The data emphasize that extrapolations from continuous cell lines in vitro to tumour cells in vivo are not necessarily valid. A high content of cellular fibronectin was correlated with a compact colony morphology in soft agar and rapid attachment and spreading on plastic. The growth rates and cellular morphology of the cell lines were strongly influenced by TPA, DMSO, retinoic acid and theophylline, but not by alpha-melanocyte-stimulating hormone. A murine cell line established from one of the xenografts grew in soft agar and produced sarcoma in mice. The malignant murine cells had arisen by transformation of murine stromal cells during the first subcultures in vitro, possibly caused by a factor produced by the human melanoma cells.
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PMID:Do cell lines in vitro reflect the properties of the tumours of origin? A study of lines derived from human melanoma xenografts. 732 90

Corticotropin-induced secreted protein (CISP) is a trimeric protein secreted by bovine adrenocortical cells in response to ACTH, that is likely to represent the bovine form of thrombospondin-2 (TSP2). This study was aimed at delineating the respective effects of CISP/TSP2 and TSP1 (thrombospondin-1) on adrenocortical cell attachment and spreading. TSP1 and CISP/TSP2 were found to slightly reduce the attachment of adrenocortical cells to plastic in the presence of serum but exhibited a pronounced differential effect on cell spreading. CISP/TSP2 inhibited adrenocortical cell spreading in a dose-dependent manner (maximal effect with 40 micrograms/ml) whereas TSP1 (up to 100 micrograms/ml) did not influence this process. The inhibition of spreading was observed whether plates were coated with CISP/TSP2 alone or with a mixture of CISP/TSP2 and fibronectin. We suggest that the inhibition of in vitro adrenocortical cell spreading by CISP/TSP2 is indicative of an implication of this protein in the migration of adrenocortical cells in vivo.
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PMID:Distinct effects of thrombospondin-1 and CISP/thrombospondin-2 on adrenocortical cell spreading. 789 6

Fibronectin is a ubiquitous extracellular matrix (ECM) protein known to play a critical role in cell adhesion. In the present study we dissected the effects of glucocorticoids and cyclic adenosine 3',5'-monophosphate (cAMP) on FN expression in cultures of cytotrophoblasts isolated from human term placentas to identify compounds which may influence uterine-placental adherence. Based on immunoassay data, relative to controls, glucocorticoid treatment (1-1000 nM) of cytotrophoblasts specifically inhibited media levels of oncofetal FN (i.e., FNs bearing an oncofetal epitope) 65-92%. Treatment of cytotrophoblasts with androgens, estrogens, and progestins (1-1000 nM) did not markedly affect onfFN expression. Corticotropin-releasing hormone (CRH) treatment (200 nM) alone had no effect on levels on onfFN. In combination experiments using 100 nM dexamethasone (DEX), 1000 nM medroxyprogesterone acetate (MPA), 10 nM estradiol (E2) and 200 nM corticotropin-releasing hormone CRH, we observed that DEX treatment also promoted approximately an 85% reduction in media levels of onfFN. This indicated that glucocorticoids profoundly suppress FN expression in the presence of high concentrations of other steroids and pregnancy-associated paracrine effectors. To examine the influence of ECM protein composition on glucocorticoid-mediated suppression of onfFN expression, cells were inoculated on untreated culture wells or on wells coated with FN, laminin, or collagen I. We observed that DEX treatment downregulated onfFN levels 70-85% under each of these conditions, suggesting that glucocorticoid effects on FN expression were not dependent on the presence of an exogenous ECM. Treatment of cytotrophoblasts with 8-bromo-cAMP resulted in a dose-dependent reduction in onfFN expression to 3% of control levels with an EC50 of 150 nM. Based on Northern blotting, treatment of cytotrophoblasts with 100 nM DEX, 1 mM 8-bromo-cAMP, or 2 nM relaxin inhibited steady state levels of FN mRNA approximately 90% relative to controls. Our results suggest that during pregnancy glucocorticoids and compounds that alter intracellular concentrations of cAMP may profoundly suppress FN expression and therefore may have dramatic effects on uterine-placental adherence.
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PMID:Negative regulation of placental fibronectin expression by glucocorticoids and cyclic adenosine 3',5'-monophosphate. 797 10

This study demonstrated morphological changes in glial-like cells of the rat pituitary intermediate lobe during early postnatal development, and a subsequent shift in protein expression from vimentin to GFAP. Vimentin immunoreactivity was detected in the lobe at embryo day 14 and was localized in radially-oriented, bipolar cells whose processes spanned the thickness of the intermediate lobe. At electron microscopical resolution, processes contained intermediate filaments, cell nuclei were indented while secretory vesicles characteristic of the endocrine cells were not found. Vimentin immunoreactive intensity began to decrease at postnatal day 5. By postnatal day 7, vimentin-positive, stellate cells were observed, with few radial processes found by day 10. The intensity of vimentin immunoreactivity decreased through day 25. Within the lobe parenchyma, vimentin was localized in glial-like cells since double-label immunohistochemistry revealed no colocalization of beta-endorphin and vimentin, or fibronectin and vimentin. Dopamine-containing axons were in close apposition to vimentin-positive processes. GFAP immunoreactivity first appeared on postnatal day 20 and, by day 25, stellate cell bodies with three to six extended processes were evident. Cells were primarily distributed in the caudal third of the lobe. The characteristic adult pattern of cell clusters in latero-dorsal and ventral portions of the lobe was fully established by postnatal day 55. The transition from vimentin to GFAP expression and concurrent morphological changes resemble those described for radial glial during cerebral cortical development.
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PMID:Glial-like cells of the rat pituitary intermediate lobe change morphology and shift from vimentin to GFAP expression during development. 855 90

Recent reports show that alpha-MSH (melanocyte-stimulating hormone) is mitogenic and melanogenic for normal human melanocytes, and that this effect is mediated through binding to the melanocortin receptor (MC1R) and activation of cAMP formation. alpha-MSH has also been shown to induce changes in cell shape in melanocytes and melanoma cells, particularly increased dendricity, suggesting a potential role for alpha-MSH in melanocyte-matrix interactions and pigment transfer through reorganization of the melanocyte actin filament cytoskeleton. In this report we show that the potent alpha-MSH analog (Nle4, D-Phe7)-alpha-MSH (NDP-MSH) induces reorganization of the actin stress fiber cytoskeleton in treated human melanocytes and that this reorganization is associated with increased adhesion to fibronectin (FN). Because most melanocyte growth factors act synergistically on melanocyte mitogenesis, we also sought to determine the effect of the melanocyte mitogen endothelin-1 (ET-1) on the melanocyte actin cytoskeleton, melanocyte adhesion, and melanocyte migration. We show that ET-1, which increases melanocyte migration on FN, has opposite effects on melanocyte adhesion to FN compared with NDP-MSH and that endothelin-1-induced actin reorganization is distinct from that observed following NDP-MSH treatment. Finally, we show that focal adhesion kinase (pp125FAK), a nonreceptor tyrosine kinase associated with focal contact formation and cell migration, is phosphorylated on tyrosine residues after treatment of melanocytes with ET-1, but not NDP-MSH. These data indicate that while alpha-MSH and ET-1 act synergistically to modulate melanocyte proliferation, they have opposite effects on melanocyte-matrix interactions.
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PMID:Alpha-melanocyte-stimulating hormone and endothelin-1 have opposing effects on melanocyte adhesion, migration, and pp125FAK phosphorylation. 941 62

We have examined the effect of alpha-melanocyte-stimulating hormone (alpha-MSH) on invasive ability of murine melanoma cell lines with different metastatic potential in a Matrigel invasion assay. alpha-MSH potently blocked the invasion of B16-BL6 cells with highly metastatic potential in a concentration-dependent manner, whereas it was less effective in inhibiting the invasion of weakly metastatic B16-F1 cells. Pretreatment of B16-BL6 cells with alpha-MSH resulted in a decrease of the adhesiveness to fibronectin and laminin substrates in a time-dependent fashion. As assessed by zymographic analysis, alpha-MSH partially inhibited the production of matrix metalloproteinase (MMP)-2 and -9 from both cell lines to a similar degree without affecting the degradative activity of these MMPs. alpha-MSH was more potent in inhibiting the migration of B16-BL6 cells towards both fibronectin- and laminin-coated substrates than that of B16-F1 cells. The growth and morphology of B16-BL6 cells were not changed after a 7-day incubation with alpha-MSH. The number of lung tumor colonies markedly decreased when B16-BL6 cells were coinjected intravenously with 10(-6) M alpha-MSH. However, alpha-MSH had no effect on the experimental lung metastases by B16-F1 cells. These results suggest that alpha-MSH suppressed the invasive and metastatic properties of B16 melanoma cells, and the degree of inhibition was associated with metastatic potential of B16 melanoma cells.
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PMID:Alpha-melanocyte-stimulating hormone blocks invasion of reconstituted basement membrane (Matrigel) by murine B16 melanoma cells. 956 Oct 27

A study of bovine adrenocortical cell shape on adrenocorticotropic hormone (ACTH) challenge showed that the cells round up and develop arborized processes. This effect was found to be (1) specific for ACTH because angiotensin II and basic fibroblast growth factor have no effect; (2) mediated by a cAMP-dependent pathway because forskolin reproduces the effect of the hormone; (3) inhibited by sodium orthovanadate, a phosphotyrosine phosphatase inhibitor, but unchanged by okadaic acid, a serine/threonine phosphatase inhibitor; and (4) correlated with a complete loss of focal adhesions. Biochemical studies of the focal-adhesion-associated proteins showed that pp125fak, vinculin (110 kDa) and paxillin (70 kDa) were detected in the Triton X-100-insoluble fraction from adrenocortical cells. During cell adhesion on fibronectin as substratum, two major phosphotyrosine-containing proteins of molecular masses 125 and 68 kDa were immunodetected in the same fraction. A dramatic decrease in the extent of tyrosine phosphorylation of these proteins was observed within 60 min after treatment with ACTH. No change in pp125fak tyrosine phosphorylation nor in Src activity was detected. In contrast, paxillin was found to be tyrosine-dephosphorylated in a time-dependent manner in ACTH-treated cells. Sodium orthovanadate completely prevented the effect of ACTH. These observations suggest a possible role for phosphotyrosine phosphatases in hormone-dependent cellular regulatory processes.
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PMID:Hormonal regulation of focal adhesions in bovine adrenocortical cells: induction of paxillin dephosphorylation by adrenocorticotropic hormone. 960 Oct 84

We have previously reported that neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) successfully inhibited Matrigel invasion and haptotactic migration of B16-BL6 melanoma cells towards both fibronectin and laminin without affecting their growth. In the present study, we investigated the inhibitory mechanism of tumor cell motility by alpha-MSH. Alpha-MSH significantly blocked the autocrine motility factor (AMF)-enhanced cell motility. However, alpha-MSH did neither prevent the secretion of AMF from B16-BL6 cells nor alter the expression level of AMF receptor (gp78). On the other hand, alpha-MSH induced the secretion of the motility inhibitory factor(s) from B16-BL6 cells in a concentration- and time-dependent manner. The induction of the motility inhibitor(s) was proportional to increasing levels of intracellular cAMP induced by alpha-MSH as well as forskolin, and the activity was abolished by an adenylate cyclase inhibitor, 2',5'-dideoxyadenosine (DDA). The motility-inhibiting activity in conditioned medium (CM) from alpha-MSH-treated B16-BL6 cells was found to have a m.w. below 3 kDa after fractionation. This activity was abolished by boiling but insensitive to trypsin. The treatment of tumor cells with cycloheximide reduced the activity in alpha-MSH-stimulated CM. Our results suggest that alpha-MSH inhibited the motility of B16-BL6 cells through induction of autocrine factor(s).
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PMID:Induction of autocrine factor inhibiting cell motility from murine B16-BL6 melanoma cells by alpha-melanocyte stimulating hormone. 1007 23

The invasion of melanoma is complex and multi-staged and involves changes in both cell/extracellular matrix (ECM) and cell/cell interactions. Female steroids and alpha-MSH have also been reported to influence metastatic melanoma progression, but their mechanisms of action are unknown. Accordingly, our aim was to establish in vitro models to examine (a) the influence of sex steroids and alpha-melanocyte-stimulating hormone (alpha-MSH) on tumour invasion and the influence of (b) ECM proteins and (c) adjacent cells on melanoma invasion. In the first model, melanoma cell invasion through fibronectin over 20 hr under serum-free conditions was used to investigate the effects of 17beta-oestradiol and oestrone on the invasion of human melanoma cell lines, A375-SM and HBL. A375-SM, but not HBL cells, proved very susceptible to inhibition by female steroids. However, invasion of the HBL line was inhibited by alpha-MSH. Using the second model of reconstructed human skin based on de-epidermised acellular dermis, we found that the HBL cells on their own failed to invade into the dermis (irrespective of the presence or absence of the basement membrane). However, there was a significant synergistic interaction between keratinocytes, fibroblasts and HBL cells, such that a modest invasion of HBLs into the dermis was seen within 2 weeks when other skin cells were present. In contrast, A375-SM cells showed a significant ability to invade the dermis in the absence of other cells, with less invasion when other skin cells were present. In summary, these models have provided new information on the extent to which melanoma cell invasion is sensitive to oestrogenic steroids and to alpha-MSH and to interaction, not only with adjacent skin cells but also to the presence of basement membrane antigens.
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PMID:Oestrogenic steroids and melanoma cell interaction with adjacent skin cells influence invasion of melanoma cells in vitro. 1104 60


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