Biochemical and biophysical research communications
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Biochem. Biophys. Res. Commun. · Oct 2000
Cytotoxic activity of recombinant bFGF-rViscumin fusion proteins.
A fusion protein (bFGF-rMLA), containing the mitogen basic fibroblast growth factor (bFGF) and the cytotoxic component of rViscumin (recombinant mistletoe lectin), the enzymatic A-chain (rMLA), was expressed in Escherichia coli, purified, and functionally characterized. bFGF-rMLA is cytotoxic for mouse B16 melanoma cells expressing the FGF receptor with an IC(50) value of approximately 1 nM. rMLA shows no significant effect on the viability of the B16 cells up to a concentration of 141 nM. Additionally, bFGF-rMLA was associated with the rViscumin B-chain (rMLB) in an in vitro folding procedure. ⋯ Thus, it was possible to enhance the efficacy of a rViscumin A-chain mitotoxin through addition of rMLB. We conclude that rViscumin fusion proteins may be generally applicable for the receptor-specific inactivation of target cells and point out their potential in drug development.
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Biochem. Biophys. Res. Commun. · May 2000
Nitric oxide inhibits inducible nitric oxide synthase mRNA expression in RAW 264.7 macrophages.
Using cultured murine RAW 264.7 macrophages, the present study investigates the influence of nitric oxide (NO) on the expression of the inducible NO synthase (iNOS) enzyme at the transcriptional level. Incubation of cells with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) led to a marked increase in iNOS mRNA levels. Inhibition of LPS/IFN-gamma-induced NO synthesis with the L-arginine analogue N(G)-monomethyl-L-arginine (L-NMMA) was accompanied by a significant up-regulation of iNOS mRNA that was reversed in the presence of the NO donor sodium nitroprusside (SNP). ⋯ In agreement with this finding, incubation of cells with the membrane-permeable cyclic GMP analogue 8-bromo cyclic GMP left LPS/IFN-gamma-induced iNOS mRNA expression virtually unaltered. Together, our results demonstrate that both iNOS-derived and exogenous NO exert an inhibitory effect on the expression of iNOS by a mechanism independent of the soluble guanylyl cyclase/cyclic GMP pathway. In conclusion, NO may control the extent of iNOS mRNA expression by a negative autoregulatory feedback.
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Biochem. Biophys. Res. Commun. · Apr 2000
Inhibition of human lung cancer cell growth by the peroxisome proliferator-activated receptor-gamma agonists through induction of apoptosis.
Peroxisome proliferator-activated receptors (PPARs), members of the nuclear hormone receptors superfamily, have an important regulatory role in adipogenesis and inflammation. PPAR-gamma ligands induce terminal differentiation and growth inhibition of human breast cancer cells and prostatic cancer cells. ⋯ However, PPAR-alpha agonist (bezafibrate) and other prostanoids (PGE(2), PGF(2alpha)) did not induce apoptosis. These findings suggest that PPAR-gamma may play an important role in the pathogenesis of lung cancer and that PPAR-gamma agonist may be useful therapeutic agents in the treatment of human lung cancer.
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Biochem. Biophys. Res. Commun. · Apr 2000
Comparative StudyThe mevalonate/isoprenoid pathway inhibitor apomine (SR-45023A) is antiproliferative and induces apoptosis similar to farnesol.
Apomine (SR-45023A) is a new antineoplastic compound which is currently in clinical trials and representative of the family of cholesterol synthesis inhibitors 1,1-bisphosphonate esters. Apomine inhibits growth of a wide variety of tumor cell lines with IC(50) values ranging from 5 to 14 microM. The antiproliferative activity of apomine was studied in comparison with that of other inhibitors of the mevalonate/isoprenoid pathway of cholesterol synthesis, simvastatin, farnesol, and 25-hydroxycholesterol. ⋯ Apomine and farnesol induced caspase-3 activity at concentrations similar to their IC(50) values for cell proliferation, whereas a 10-fold excess of simvastatin was necessary to trigger apoptosis compared to its potency on proliferation. Caspase-3 activity was not induced by 25-hydroxycholesterol. The overall similar profile on mevalonate synthesis inhibition, cell growth inhibition, and apoptosis suggests that apomine acts as a synthetic mimetic of farnesol.
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Biochem. Biophys. Res. Commun. · Mar 2000
The suppression of small GTPase rho signal transduction pathway inhibits angiogenesis in vitro and in vivo.
Angiogenesis consists of multistep pathways such as the degradation of the matrix, proliferation of the endothelial cells, motility of the endothelial cells, formation of the cord structure and network formation of microvessels. The small GTPase Rho participates in cell motility through actin fiber polymerization. ⋯ In this paper, we showed that the small GTPase Rho-p160ROCK signal transduction pathway played an important role in angiogenesis both in vitro and in vivo. These results suggest that inhibition of the small GTPase Rho signal transduction pathway by the p160ROCK inhibitor could be a possible new strategy for angiogenic diseases.