References of "Krell, H. W"
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See detailType Iv Collagen Induces Matrix Metalloproteinase 2 Activation in Ht1080 Fibrosarcoma Cells
Maquoi, Erik ULg; Frankenne, F.; Noël, Agnès ULg et al

in Experimental Cell Research (2000), 261(2), 348-59

Matrix metalloproteinase 2 (MMP-2) activation has been described as a "master switch" which triggers tumor spread and metastatic progression. We show here that type IV collagen, a major component of ... [more ▼]

Matrix metalloproteinase 2 (MMP-2) activation has been described as a "master switch" which triggers tumor spread and metastatic progression. We show here that type IV collagen, a major component of basement membranes, promotes MMP-2 activation by HT1080 cells. When plated on plastic, HT1080 cells constitutively processed the 66-kDa pro-MMP-2 into a 62-kDa intermediate activated form, most probably through a membrane type (MT) 1 MMP-dependent mechanism. In the presence of type IV collagen, part of this intermediate form was further processed to fully activated 59-kDa MMP-2. This activation was prevented by tissue inhibitor of MMP (TIMP)-2 and a broad-spectrum hydroxamic acid-based synthetic MMP inhibitor (GI129471). Type IV collagen-mediated pro-MMP-2 activation did not involve either a transcriptional modulation of MMP-2, MT1-MMP, or TIMP-2 expression nor any alteration of MT1-MMP protein synthesis or processing. An inverse relationship between MMP-2 activation and the concentration of secreted TIMP-2 was observed. This is consistent with our previous report that TIMP-2 degradation is probably linked to the MT1-MMP-dependent MMP-2 activation mechanism. Because invasive tumor cells must breach basement membranes at different steps of the metastatic dissemination, the ability of HT1080 cells to activate pro-MMP-2 in the presence of type IV collagen might represent a key regulatory mechanism for the acquisition of an invasive potential. [less ▲]

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See detailInvolvement of Pa/Plasmin System in the Processing of Pro-Mmp-9 and in the Second Step of Pro-Mmp-2 Activation
Baramova, E. N.; Bajou, Khalid ULg; Remacle, A. et al

in FEBS Letters (1997), 405(2), 157-62

Pro-MMP2 activation is a two-step process resulting in (1) an intermediate 64 kDa form generated by the MT1-MMP activity, and (2) a mature 62 kDa form. Addition of plasminogen to HT1080 cells cultured ... [more ▼]

Pro-MMP2 activation is a two-step process resulting in (1) an intermediate 64 kDa form generated by the MT1-MMP activity, and (2) a mature 62 kDa form. Addition of plasminogen to HT1080 cells cultured under various conditions, or to their membrane preparation, induced a complete conversion of the intermediate MMP-2 form to the mature one, and processing of pro-MMP-9. The pro-MMP-2 activation was inhibited by plasmin inhibitors and anti-uPA antibody. These results provide evidence for involvement of the PA/plasmin system in the second step of MMP-2 activation. [less ▲]

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See detailPurification of Progelatinases A and B by Continuous-Elution Electrophoresis
Remacle, A. G.; Baramova, E. N.; Weidle, U. H. et al

in Protein Expression & Purification (1995), 6(4), 417-22

Progelatinases A and B were purified from HT1080-conditioned culture medium using a continuous-elution electrophoresis. Initially cell culture medium was ammonium sulfate precipitated. The concentrated ... [more ▼]

Progelatinases A and B were purified from HT1080-conditioned culture medium using a continuous-elution electrophoresis. Initially cell culture medium was ammonium sulfate precipitated. The concentrated proteins were affinity chromatographed on gelatin-Sepharose column. The bound gelatinases were eluted with electrophoresis sample buffer and subjected to continuous-elution electrophoresis. In a single run, under the standardized working conditions, the obtained fractions contained four purified enzymes--progelatinase A (M(r) 72,000), its activated forms (M(r) 62,000 and M(r) 59,000), and progelatinase B (M(r) 92,000). Moreover, the continuous-elution electrophoresis allowed the enzymes separation from their respective inhibitors--TIMP-1 (M(r) 28,500) and TIMP-2 (M(r) 21,000). The purified progelatinases A and B demonstrated high specific activities (150-200 U/micrograms). [less ▲]

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See detailModulation of the Expression of Interstitial and Type-Iv Collagenases in Coculture of Ht1080 Fibrosarcoma Cells and Fibroblasts
Munaut, Carine ULg; Noël, Agnès ULg; Weidle, U. H. et al

in Invasion & Metastasis (1995), 15(5-6), 169-78

Members of the metalloproteinase family (MMPs) are known to play a crucial role in the metastatic cascade. Here, we report some investigations about the synthesis of interstitial and type-IV collagenases ... [more ▼]

Members of the metalloproteinase family (MMPs) are known to play a crucial role in the metastatic cascade. Here, we report some investigations about the synthesis of interstitial and type-IV collagenases (gelatinases A and B) in a model of coculture of human fibroblasts and HT 1080 fibrosarcoma cells. The interstitial collagenase activity, mainly found in the conditioned medium of fibroblasts, and its mRNA level were increased in the in vitro coculture model. In contrast, gelatinase A was produced by both cell types. The HT 1080 cells additionally synthesised gelatinase B. In coculture, an enhancement of gelatinase A and the presence of its activated form were observed. Northern blot analysis demonstrated that this enzymatic enhancement occurred at a pretranslational level. The stimulation of the interstitial collagenase activity was partially mediated through soluble factor(s), whereas increased gelatinase A appeared to require direct cell-cell interactions. The extracellular matrix component, type-I collagen, stimulated the enzymatic activities released by the individual cells, but it did not modulate the synthesis of interstitial collagenase in coculture. Our results demonstrate that distinct MMPs are modulated by distinct mechanisms, all depending on specific interactions between tumour cells and host fibroblasts. [less ▲]

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