Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunohistochemical and/or indirect immunofluorescence analysis with monoclonal antibody (MAb) H19 demonstrated the expression of protectin (CD59) in 54 surgically removed metastatic melanoma lesions and on 8 out of 12 melanoma cell lines. CD59 expression had a low degree of intra- and intertumor heterogeneity. SDS-PAGE analysis showed that the molecular weight of CD59 expressed on melanoma cells is about 20 kDa. Treatment of melanoma cells with 5U/ml of phosphatidylinositol-specific phospholipase C completely abolished cell-surface expression of CD59. Interferon-gamma and/or tumor necrosis factor-alpha or phorbol 12-myristate 13-acetate neither modulated the expression of CD59 by melanoma cells nor influenced the amounts of CD59-specific mRNA. F(ab')2 fragments of anti-CD59 MAb YTH53. I did not inhibit the lysis of melanoma cells by allogeneic natural killer (NK) cells or lymphokine-activated killer (LAK) cells. In contrast, the whole Ig molecule of MAb HI9 or YTH53.I significantly (p < 0.05) enhanced NK-cell-mediated lysis of melanoma cells, suggesting the induction of antibody-dependent cell-mediated cytotoxicity. Lastly, masking of CD59 by MAb YTH53.I or its F(ab')2 fragments significantly (p < 0.05) enhanced, in a dose-dependent fashion, the lysis of anti-GD3-sensitized melanoma cells by homologous complement. These data demonstrate that CD59 expressed by human melanoma cells might regulate host-tumor interaction by protecting neoplastic cells from complement-mediated lysis.
 ...
PMID:Expression of protectin (CD59) in human melanoma and its functional role in cell- and complement-mediated cytotoxicity. 753 80

Recent studies have demonstrated altered expression and function of signaling molecules in T and natural killer cells in patients with cancer. The impairment of immune cell functions in advanced cancer may result from defects in signal transduction. We studied purified T cells obtained from peripheral blood or tumor-involved lymph nodes (LNs) of 45 patients with advanced metastatic melanoma for the presence of abnormalities in expression or activity of various signaling molecules. Western blot analyses demonstrated reduced expression of CD3-zeta in 10 of 11 preparations of T cells obtained from tumor-involved LNs. Similar reduction in expression of CD3-zeta was demonstrated by immunostaining performed in situ on frozen sections of melanoma tissues. Expression of p56(lck) and Zap-70, but not phospholipase C-gamma1, was reduced in these patients' T cells relative to those obtained from normal individuals. In 50% of the patients, reduced expression of CD3-zeta and p56(lck) was observed in T lymphocytes obtained both from tumor-involved LNs and from peripheral blood. To determine whether deficient expression of these signaling molecules is reversible, T cells from melanoma-involved LNs were incubated in the presence of interleukin 2 (IL-2) for 48 h, and lysates from fresh or cultured lymphocytes were compared for changes in expression of signaling molecules. Cells cultured in the presence of IL-2 demonstrated increased expression of CD3-zeta and p56(lck), which approached the levels detected in normal T cells. However, the level of p56(lck) kinase activity did not normalize in any of the LN-derived lymphocytes cultured in the presence of IL-2. Decreased expression of CD3-zeta or p56(lck) observed in the patients' T cells was not reversed by immunotherapy with IL-2 at low or high dose in those patients with metastatic melanoma who failed to respond to therapy. However, in three patients who achieved clinical responses, the initially reduced expression of zeta in peripheral blood T cells normalized following IL-2 therapy.
 ...
PMID:Expression and activity of signaling molecules in T lymphocytes obtained from patients with metastatic melanoma before and after interleukin 2 therapy. 981 96

Melanoma has a poor prognosis due to its strong metastatic ability. Although Ca(2+) plays a major role in cell migration, little is known about the role of Ca(2+) in melanoma cell migration. We recently found that the exchange protein directly activated by cyclic AMP (Epac) increases melanoma cell migration via a heparan sulfate-related mechanism. In addition to this mechanism, we also found that Epac regulates melanoma cell migration by a Ca(2+)-dependent mechanism. An Epac agonist increased Ca(2+) in several different melanoma cell lines but not in melanocytes. Ablation of Epac1 with short hairpin RNA inhibited the Epac agonist-induced Ca(2+) elevation, suggesting the critical role of Epac1 in Ca(2+) homeostasis in melanoma cells. Epac-induced Ca(2+) elevation was negated by the inhibition of phospholipase C (PLC) and inositol triphosphate (IP(3)) receptor. Furthermore, Epac-induced cell migration was reduced by the inhibition of PLC or IP(3) receptor. These data suggest that Epac activates Ca(2+) release from the endoplasmic reticulum via the PLC/IP(3) receptor pathway, and this Ca(2+) elevation is involved in Epac-induced cell migration. Actin assembly was increased by Epac-induced Ca(2+), suggesting the involvement of actin in Epac-induced cell migration. In human melanoma specimens, mRNA expression of Epac1 was higher in metastatic melanoma than in primary melanoma, suggesting a role for Epac1 in melanoma metastasis. In conclusion, our findings reveal that Epac is a potential target for the suppression of melanoma cell migration, and, thus, the development of metastasis.
 ...
PMID:Exchange protein directly activated by cyclic AMP increases melanoma cell migration by a Ca2+-dependent mechanism. 2055 Oct 63

Metastatic melanoma is an aggressive cancer with a poor prognostic, and the design of new targeted drugs to treat melanoma is a therapeutic challenge. A promising approach is to produce monoclonal antibodies (mAbs) against the endothelin B receptor (ETB), which is known to be overexpressed in melanoma and to contribute to proliferation, migration and vasculogenic mimicry associated with invasiveness of this cancer. We previously described rendomab-B1, a mAb produced by DNA immunization. It is endowed with remarkable characteristics in term of affinity, specificity and antagonist properties against human ETB expressed by the endothelial cells, but, surprisingly, had poor affinity for ETB expressed by melanoma cells. This characteristic strongly suggested the existence of a tumor-specific ETB form. In the study reported here, we identified a new mAb, rendomab-B4, which, in contrast to rendomab-B1, binds ETB expressed on UACC-257, WM-266-4 and SLM8 melanoma cells. Moreover, after binding to UACC-257 cells, rendomab-B4 is internalized and colocalizes with the endosomal protein EEA-1. Interestingly, rendomab-B4, despite its inability to compete with endothelin binding, is able to inhibit phospholipase C pathway and migration induced by endothelin. By contrast, rendomab-B4 fails to decrease ERK1/2 phosphorylation induced by endothelin, suggesting a biased effect on ETB. These particular properties make rendomab-B4 an interesting tool to analyze ETB-structure/function and a promising starting point for the development of new immunological tools in the field of melanoma therapeutics.
 ...
PMID:Rendomab B4, a monoclonal antibody that discriminates the human endothelin B receptor of melanoma cells and inhibits their migration. 2739 Sep 9