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)

Modulation of tumour cell growth by tumour-infiltrating leucocytes is of high importance for the biological behaviour of malignant neoplasms. In melanoma, tumour-associated macrophages (TAM) and tumour-infiltrating lymphocytes (TIL) are of particular interest as inhibitors or enhancers of cell growth. Recruitment of leucocytes from the peripheral blood into the tumour site is mediated predominantly by chemotaxins, particularly by the group of chemokines. The aim of this study was to identify peptides released by human melanoma cells with monocyte chemotactic properties. To assure the presence of biologically active mediators, biochemical purification and biological characterization of peptides was based on a detection system dependent on bioactive, monocyte chemotactic activity in vitro. Cell culture supernatants of melanoma cells were fractioned by heparin-sepharose followed by preparative reversed-phase HPLC steps to enrich monocyte chemotactic activity in one single band on a sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) gel. These purified fractions were shown to react with RANTES-specific antibodies in an enzyme-linked immunosorbent assay (ELISA) as well as in Western blot analysis. Amino acid sequencing of the N-terminal protein fragment confirmed 100% homology to the RANTES protein. Further analysis showed that four out of eight melanoma cell lines constitutively expressed and secreted the beta-chemokine RANTES as detected by ELISA. The amount of RANTES protein secreted (up to 50 ng ml(-1)) was about 5-50 times higher than interleukin 8 (IL-8), determined in the same supernatant samples. Tumour necrosis factor alpha, (TNF-alpha), not, however, IL-2, interferon-gamma (IFN-gamma), or (alpha-melanocyte-stimulating hormone (alpha-MSH) was able to up-regulate RANTES and interleukin 8 secretion. Furthermore, higher levels of RANTES secretion in vitro were associated with increased tumour formation upon s.c. injection of six human melanoma cell lines in nude mice. Our data provide evidence that a subset of melanoma cells express mRNA and secrete RANTES protein which may be partly responsible for the recruitment of monocytes, T-cells and dendritic cells into the tumours. However, transplantation experiments in nude mice suggest that effects of RANTES may also benefit tumour progression. Further studies are needed to dissect the underlying mechanisms.
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PMID:The chemokine RANTES is secreted by human melanoma cells and is associated with enhanced tumour formation in nude mice. 1009 31

1. Tumour necrosis factor (TNF-alpha) is involved in the pathogenesis of splanchnic artery occlusion (SAO) shock. On the other hand, inhibition of TNF-alpha is an important component of the mechanism of action of melanocortins in reversing haemorrhagic shock. We therefore investigated the effects of the melanocortin peptide ACTH-(1 - 24) (adrenocorticotropin fragment 1 - 24) on the vascular failure induced by SAO shock. 2. SAO-shocked rats had a decreased survival rate (0% at 4 h of reperfusion, while sham-shocked rats survived for more than 4 h), enhanced serum TNF-alpha concentrations (755+/-81 U ml-1), decreased mean arterial blood pressure, leukopenia, and increased ileal leukocyte accumulation, as revealed by means of myeloperoxidase activity (MPO=9.4+/-1 U g-1 tissue). Moreover, aortic rings from shocked rats showed a marked hyporeactivity to phenylephrine (PE, 1 nM - 10 microM) (Emax and ED50 in shocked rats=7.16 mN mg-1 tissue and 120 nM, respectively; Emax and ED50 in sham-shocked rats=16.31 mN mg-1 tissue and 100 nM, respectively), reduced responsiveness to acetylcholine (ACh, 10 nM-10 microM) (Emax and ED50 in shocked rats=30% relaxation and 520 nM, respectively; Emax and ED50 in sham-shocked rats=82% relaxation and 510 nM, respectively) and increased staining for intercellular adhesion molecule-1 (ICAM-1). 3. ACTH-(1 - 24) [160 microg kg-1 intravenously (i.v.), 5 min after SAO] increased survival rate [SAO+ACTH-(1 - 24)=80% at 4 h of reperfusion], reversed hypotension, reduced serum TNF-alpha (55+/-13 U ml-1), ameliorated leukopenia, reduced ileal MPO (1.2+/-0.2 U g-1 tissue), restored the reactivity to PE, improved the responsiveness to ACh and blunted the enhanced immunostaining for ICAM-1 in the aorta. 4. Adrenalectomy only in part - but not significantly - reduced the ACTH-induced shock reversal, the survival rate of SAO+ACTH-(1 - 24) adrenalectomized rats being 60% at 4 h of reperfusion; and methylprednisolone (80 mg-1 i.v., 5 min after SAO) had a non-significant effect (10% survival) at 4 h of reperfusion. 5. The present data show that melanocortins are effective also in SAO shock, their effect being, at least in part, mediated by reduced production of TNF-alpha. Furthermore, they demonstrate, for the first time, that this inhibition is responsible for the adrenocorticotropin-induced reversal of vascular failure and leukocyte accumulation.
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PMID:Adrenocorticotropin reverses vascular dysfunction and protects against splanchnic artery occlusion shock. 1051 67