Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Challenge of mammalian cells with heavy metals or sulfhydryl-reactive agents including sodium arsenite induces the de novo synthesis of a 32-/34-kDa stress protein (p32) (M. M. Caltabiano, T. P. Koestler, G. Poste, and R. G. Greig (1986) J. Biol. Chem. 261, 13,381). Here we report that antibody prepared against p32/p34 purified from human A375 melanoma cells immunoprecipitated an antigen of similar molecular mass from a panel of human, rat, and murine cells following challenge with sodium arsenite. No reactivity was observed in lysates from control, uninsulted cultures. The precise molecular mass of the arsenite-induced antigen was species-specific: 32 kDa (human and rat) and 34 kDa (murine). Indirect immunofluorescence analysis using affinity-purified monospecific IgG demonstrated that p32/p34 was localized to the cytoplasm and displayed a perinuclear distribution.
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PMID:Isolation and immunological characterization of the mammalian 32-/34-kDa stress protein. 245 4

Activity of peritoneal plasminogen activator and its regulation by dextran and other macromolecules that clinically suppress postoperative adhesions was studied. Plasminogen activator activity was assayed by a two-stage globinolytic assay that monitors formation of plasmin, as well as by cleavage of a chromogenic peptide substrate (S-2444) in the presence of aprotinin (Trasylol). Plasminogen activator activity was located on the outer surface of human peritoneum. Incubation of peritoneal tissue with buffer in vitro (conditioning) prompted release of plasminogen activator into the conditioning medium. The released plasminogen activator formed a single band on sodium dodecyl sulfate-gel electrophoresis at an apparent molecular weight of 174,000 and was markedly suppressed by antiserum raised against human melanoma tissue-type plasminogen activator. Nonspecific proteolytic activity did not accumulate in the medium during conditioning. The presence of dextran 80 during conditioning of peritoneum reversibly suppressed tissue-bound plasminogen activator activity and reduced plasminogen activator activity in the spent medium. A similar inhibition of peritoneal plasminogen activator was induced by dextran 500, methyl cellulose, and polyvinylpyrrolidone. Dextran, when added to the medium after conditioning, had no direct inhibitory effect on plasminogen activator activity. Dextran did not induce peritoneal production of inhibitor(s) of trypsin, chymotrypsin, or urokinase. On the basis of these findings, two possible mechanisms for the effect of viscous polymers in the reduction of adhesion formation are proposed. These mechanisms consider the importance of peritoneal tissue-type plasminogen activator for removal of fibrin clots and suggest that polymer coating either prevents the shedding of plasminogen activator into the abdominal cavity or reduces the access of fibrin clots to the serosal surfaces.
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PMID:Effect of viscous macromolecules on peritoneal plasminogen activator activity: a potential mechanism for their ability to reduce postoperative adhesion formation. 245 68

Normal human melanocytes, unlike malignant melanoma cells, required at least three growth-promoting agents, i.e., phorbol ester for protein kinase C activation and the growth factors basic fibroblast growth factor (bFGF) and insulin, for growth in chemically defined W489 medium. Cell growth was further stimulated by addition of agents that increase intracellular levels of cyclic adenosine 3',5'-monophosphate (cAMP) to the medium. Among these agents, the pituitary hormones alpha-melanocyte-stimulating hormone (alpha-MSH) and follicle-stimulating hormone were the most potent, whereas bacterial toxins, including cholera, tetanus, and pertussis toxin and their subunits either were less mitogenic or gave variable results depending on the culture tested. Medium containing phorbol ester PMA, growth factors bFGF and insulin (or insulin-like growth factor-I), and synthetic alpha-MSH supported melanocyte growth for more than 5 months with doubling times between 5 and 8 days. Two copper-binding proteins, ceruloplasmin and tyrosinase, were mitogenic when added to medium and ceruloplasmic induced a long bi- to tripolar-shape of cells. Addition of 1 mM dibutyryl cAMP to the medium led to the formation of dendrites in all cells, with an average of 28 extensions per cell. Although cell growth was inhibited by dibutyryl cAMP, cells were not terminally differentiated and continued to proliferate. Dendritic melanocytes showed a 2.2-fold increase in activity of the tyrosine kinase pp60c-src. The induction of dendritic processes in melanocytes by dibutyryl cAMP or sodium butyrate was reversible and appears to reflect the expression of the mature melanocytic phenotype in situ.
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PMID:Regulatory factors that determine growth and phenotype of normal human melanocytes. 246 9

Of 122 mouse monoclonal antibodies selective for human breast cancer, 13 immunoprecipitated an acidic glycoprotein from SK-Br-3 and ZR-75-30 human breast cancer cells. The antigen (BCA200) migrates with an apparent molecular weight of 200,000 on reducing and 180,000 on nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting a single polypeptide chain with a folded domain stabilized by a disulfide bond. Cross-blocking and sandwich immunoassays detected at least three distinct antigenic determinants on BCA200. Scatchard experiments measured 1,000,000 to 5,000,000 antigen copies per SK-Br-3 cell. The tissue distribution of BCA200 was studied using two monoclonals to different epitopes. Neither antibody stained any cells in human blood. When frozen sections of 20 normal human tissues were immunoperoxidase stained, the only positive structures were mucinous glands of colon, transitional epithelium of bladder, sweat glands of skin, and acinar epithelium of breast. Antibody 454C11 stained 16 of 21 breast tumor frozen sections and 9 of 12 breast cancer cell lines, while antibody 520C9 stained 5 of 20 breast tumors and 4 of 10 breast cancer lines. Cross-reaction was observed with lung, prostatic, pancreatic, endometrial, and ovarian cancer, but not with lymphoma, melanoma, colon, stomach, bladder, or esophageal cancer. When conjugated to ricin A chain, 10 of 13 antibodies produced immunotoxins selectively cytotoxic to SK-Br-3 breast cancer cells.
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PMID:Distribution and physical properties of BCA200, a Mr 200,000 glycoprotein selectively associated with human breast cancer. 247 May 1

Succinyl con A and acetyl con A both stimulated epithelial cells to produce similar yields of tissue plasminogen activator (t-PA) to those previously obtained with native con A. However, unlike con A, the derivatized lectins did not adversely affect cell morphology and viability, and cells treated with succinyl con A could secrete t-PA for a prolonged period. Con A and the two derivatives produced similar morphological effects in Bowes melanoma cells, but t-PA production was not increased. Elevated cyclic nucleotide concentrations did not affect t-PA production from epithelial cells, but calcium ionophore treatment generated t-PA yields similar to those obtained with lectins. Azacytidine, which enhanced t-PA production from epithelial cells, did not increase yields from Bowes melanoma cells, and also sodium butyrate, reported to increase t-PA yields from human endothelial cells, had no effect on either cell line.
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PMID:A comparison of the effects of various stimulatory agents on t-PA secretion by normal and malignant cell lines. 248 73

This report describes the purification and characterization of single-chain tissue-type plasminogen activator (sct-PA) present in tissue culture medium of a cell line established from human uterine muscle. The cell line used for the experiment, KW, had estrogen receptor. The PA fraction (KW-PA) was purified from the tissue culture medium of KW employing several steps of affinity chromatography and gel filtration in the presence of aprotinin. The final product (KW-PA) of purification, which predominantly contained the inactive form of sct-PA as well as active sct-PA to a lesser extent, revealed a single band with a molecular weight of 70,000 on sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis both in the absence and presence of reducing agent. Electrophoretic enzymography demonstrated a single lytic zone at Mr 70,000. When KW-sct-PA was treated with plasmin, SDS-polyacrylamide gel electrophoresis revealed two bands of Mr 37,000 and 33,000 under reduced conditions. Such plasmin treatment of KW-sct-PA enhanced the enzymatic activity as well as the [3H]DFP incorporation significantly. The KW-sct-PA demonstrated a higher affinity for lysine than did melanoma-t-PA, but the fibrin affinity of KW-sct-PA was identical with that of melanoma-t-PA. Circular dichroism (CD) analysis showed that the CD spectra of KW-sct-PA were different from those of melanoma-t-PA. These results suggest that the single-chain inactive form of t-PA which was obtained from the tissue culture medium of the cell line from human uterine muscle is activated to a two-chain form on plasmin treatment, with an accompanying significant increase in enzymatic activity.
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PMID:Production and characterization of single-chain tissue-type plasminogen activator produced by an established cell line from human uterine muscle. 249 95

A two-step method was used to purify enzymatically active tyrosinase to apparent homogeneity from B16/C3 mouse melanoma cells. The purification was based on our finding that tyrosinase was highly resistant to sodium dodecyl sulfate-proteinase K digestion. Following treatment with proteinase K, tyrosinase was separated from all detectable contaminants using DEAE-52 ion-exchange chromatography. Using this procedure, tyrosinase was purified to high specific activity and in yields greater than 50%. The purified enzyme was then used to generate high titers of specific polyclonal antibodies in rabbits. These antibodies were used to immunoprecipitate all tyrosinase isozymes from murine melanoma tumor extracts and cultured B16/C3 cells metabolically labeled with [35S]methionine.
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PMID:Purification of tyrosinase to homogeneity based on its resistance to sodium dodecyl sulfate-proteinase K digestion. 251 May 99

Lectins purified by affinity chromatography on immobilized asialofetuin from extracts of mouse K-1735P melanoma cells appeared as two polypeptides [L-14.5 (Mr 14,500) and L-34 (Mr 34,000)] in one-dimensional polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. However, in two-dimensional electrophoresis (isoelectric focusing followed by sodium dodecyl sulfate:polyacrylamide gel electrophoresis) the L-14.5 polypeptide was resolved into three acidic forms of pI 4.6, 4.9, and 5.8, whereas the L-34 was resolved into two polypeptides of pI 4.9 and 5.3. Antibodies directed against galactoside-binding lectins from rat and bovine lungs, mouse 3T3 fibroblasts, and mouse UV-2237 fibrosarcoma cells reacted with the K-1735P lectins in immunoblots, and normal mouse lung extracts were found to contain cross-reactive proteins that comigrated with the two melanoma lectins. Indirect immunofluorescence staining using the above antibodies demonstrated that both L-14.5 and L-34 were expressed on the surface of viable K-1735P cells. Treatment of these cells with 1 microM beta-all-trans-retinoic acid or 1 mM N6,O2'-dibutyryl cyclic AMP for 5 days induced morphological differentiation, inhibition of anchorage-dependent and anchorage-independent growths, and a selective decrease in the L-34 lectin level. Growth inhibition by starvation for serum factors, which did not induce differentiation, had no effect on the level of L-34. These results demonstrate that the melanoma lectins are immunologically related to normal cell lectins and that the two polypeptide species are expressed on the cell surface. Further, they demonstrate that the L-34 lectin level can be modulated by agents that suppress the transformed phenotype by enhancing differentiation.
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PMID:Biochemical and immunological characterization of K-1735P melanoma galactoside-binding lectins and their modulation by differentiation inducers. 253 46

Electron spin resonance spectroscopy using the spin probe (5-, 12- and 16-deoxylstearic acid) was employed to analyze the changes in membrane fluidity in B-16 melanoma cells following UV-B exposure. The UV exposure resulted in the immediate accumulation of lipid peroxide, being accompanied by a change in membrane fluidity. The 12-DSA is the most sensitive to the changes in membrane organization caused by UV light. Na+,K+-ATPase activity was regulated by a change in membrane fluidity. Following UV exposure, the release of the prelabeled arachidonic acid from the cells was observed immediately. Ca2+-dependent calmodulin-dependent phospholipase A2-like activity was involved in the UV-stimulated arachidonic acid release from phospholipid.
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PMID:Membrane responses of B-16 melanoma cells to single exposure to ultraviolet light. 253 9

Integrin receptors may mediate the adhesion of cells to a number of extracellular matrix components. We found that the attachment of human melanoma cells to collagen types I and IV was blocked by antibodies to the integrin beta 1 subunit but not by peptides containing the Arg-Gly-Asp sequence. Ligand affinity chromatography was used to search for integrin-related receptors which mediate adhesion to native collagens. Detergent extracts of surface 125I-iodinated melanoma cells were chromatographed on type I or IV collagen-Sepharose columns. Bound material was eluted and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. EDTA, but not Arg-Gly-Asp peptides, eluted a mixture of two integrin-related heterodimeric complexes. Each complex contained the integrin beta 1 chain with Mr of 110,000 and a distinct alpha chain with Mr of either 200,000 or 150,000. Immunoprecipitation with specific monoclonal antibodies identified the complexes as very late activation antigen (VLA)-1 (alpha 1 beta 1) and VLA-2 (alpha 2 beta 1), respectively. The binding of these receptors to collagen appeared to be specific because they failed to be retained on fibronectin- or laminin-Sepharose columns. Immunofluorescent staining of cells on collagen substrates with antibodies to VLA-1 and VLA-2 localized these complexes in vinculin-positive adhesion plaques. In contrast, the receptor complexes were not detected in adhesion plaques of cells attached to fibronectin- or laminin-coated substrates. These results indicate that melanoma cells express at least two different integrin-related collagen-binding receptor complexes that appear to mediate cell adhesion to collagen.
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PMID:Identification of integrin collagen receptors on human melanoma cells. 253 53


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