The antiviral activity of Escherichia coli-derived (Serine-17) human interferon-beta, formulated with human serum albumin, is stable for 2 years when lyophilized and stored under refrigeration. This product shows an Arrhenius line fit for the stability of its activity when tested at multiple isothermal temperatures (25-80 degrees C). In both isothermal and nonisothermal elevated temperature studies, increasing the level of human serum albumin in the formulation results in increased thermal stability.
We compared the molecular structure of the receptor to human recombinant tumor necrosis factor (HurTNF) on cells of different tissue origin that differ in their response to one of the known activities of TNF. We studied tumor cell lines that respond to the cytotoxic action of TNF and resistant variants that bind TNF, normal cell lines that are stimulated to proliferate by TNF and those that are not affected by TNF, and peripheral blood granulocytes whose activation is also augmented by TNF. Using 125I-labeled HurTNF, we found that it bound mainly to four cellular polypeptides (138, 90, 75, and 54 kDa), three of which were found in every cell type examined and one (138 kDa) that was observed only in a human breast carcinoma cell line (MCF-7) that is highly responsive to the cytotoxic action of TNF. The 138-kDa polypeptide was not found in resistant variants of MCF-7 that bind TNF. In contrast to the other polypeptides, the 138-kDa protein was detected 30 min after incubation at 4 degrees C, as compared to 5 min. Scatchard analysis and cross-linking data suggest a model for the TNF receptor structure whereby the receptor is composed of noncovalently linked membrane-bound polypeptides that bind TNF with high affinity (Kd, 0.05-0.8 X 10(-9) M) with the 138-kDa protein being the least abundant and/or even absent in most cells.
The amino acids that are required for the cytotoxic activity of recombinant human tumor necrosis factor-alpha (TNF) were investigated by chemical modification and oligonucleotide-directed site-specific mutagenesis. TNF contains three histidine residues, located at positions 15, 73 and 78. The histidine-specific reagent diethylpyrocarbonate (DEP) was used to chemically modify TNF. The chemical inactivation of the in vitro cytotoxic activity of this lymphokine (using murine L929 target cells) was found to be time- and dose-dependent. Inactivated TNF failed to compete with fully bioactive [125I]TNF for human MCF-7 target cell receptors. Mutant polypeptides of TNF were genetically engineered by oligonucoleotide-directed site-specific mutagenesis. The cytotoxicity of a double histidine mutant, in which histidine-73 and histidine-78 were replaced with glutamine, was not altered and was chemically inactivated by DEP. Substituting glutamine for histidine-15 resulted in 10-15% of the wild-type bioactivity. Replacing histidine-15 with either asparagine, lysine or glycine resulted in a biologically inactive molecule. The data show that the histidine residue at position 15 is an amino acid that is required for the cytotoxic activity of TNF.
We characterize the in vitro and in vivo pharmacology of CHIR 2279, an N-substituted glycine peptoid previously identified from a combinatorial library as a novel ligand to alpha 1-adrenoceptors. Competitive receptor-binding assays with [3H]prazosin showed that CHIR 2279 was similar to prazosin in binding to alpha 1A (rat submaxillary), alpha 1a, alpha 1b, and alpha 1 d (cDNA expressed in LTK- cells) with high and approximately equipotent affinity. Ki values for CHIR 2279 ranged from 0.7 to 3 nM, and were 10-fold weaker than with prazosin. Functional assays for postsynaptic alpha 1-adrenoceptors showed CHIR 2279 was approximately equipotent in antagonizing agonist-induced contractile responses with rat was deferens (alpha 1A), canine prostate (alpha 1A), rat spleen (alpha 1B) and rat aorta (alpha 1D). The pA2 for CHIR 2279 averaged 7.07 in these assays, indicating a 10- to 100-fold lower in vitro potency than prazosin. In dogs, CHIR 2279 antagonized the epinephrine-induced increase in intraurethal pressure (pseudo pA2, 6.86) and in rats antagonized the phenylephrine-induced increase in mean arterial blood pressure. In rats and guinea pigs, CHIR 2279 induced a dose-dependent decrease in mean arterial blood pressure without eliciting the tachycardia commonly observed with other alpha 1-blockers. Pharmacokinetic/pharmacodynamic modeling showed the i.v. system clearance rate of CHIR 2279 was 60 and 104 ml/min/kg in rats and guinea pigs, respectively, and the in vivo potency for mean arterial blood pressure reduction was twice as great in guinea pigs (EC50, 520 ng/ml) than rats (EC50, 1170 ng/ml).
We have characterized the functional properties of four highly purified recombinant human class I alpha-interferon subtypes whose biological activities have not been described previously. We selected biological and biochemical activities that may discriminate between different functions of these molecules. We found that the alpha subtypes could be discriminated only by antiviral-host range specificity and natural killer cell activation. Differences in their antiproliferative activity were cell line dependent. Competitive binding, antiproliferative activity in agar, enhancement of expression of HLA-ABC, elevation of 2'-5'-oligoadenylate synthetase levels and enhancement of phosphorylation of the Mr 69,000 protein kinase did not allow discrimination among the alpha I subtypes on the tested cell lines.
We investigated optimal conditions for cytotoxicity to tumor cell lines by recombinant human tumor necrosis factor (rhTNF) and the effect of amino-terminal deletions on the bioactivity of the rhTNF molecule. Two of four deletion muteins (-4 and -7) of rhTNF exhibit 2- to 3-fold enhancement of cytotoxicity/cytostasis against a variety of human carcinomas, a fibrosarcoma, and a melanoma cell line with no toxicity on normal fibroblastic and epithelial cultures. Of the two other muteins the -8 displayed equivalent and/or increased cytotoxicity/cytostasis while the -10 was consistently less cytotoxic than the parent on the same cell lines. Continuous exposure to TNF for greater than or equal to 96 h led to maximal cytotoxicity to tumor lines (99.99% with L929 cells) with no evidence of recovery. Pretreatment with actinomycin D (0.003-10 micrograms/ml for 1 h) rendered 82% of rhTNF-resistant cell lines (both tumor and normal) susceptible to its cytotoxic action within 24 h. However, the highest nontoxic concentrations of Actinomycin D necessary for rendering normal cell lines susceptible to TNF action were about 10-3000-fold higher than those necessary for converting resistant tumor cell lines. Similarly, preinfection of L929 cells with vesicular stomatitis virus (multiplicity of infection, 10(-2)-10(-4) for 1 h) rendered the cells 2-10-fold more susceptible to the cytotoxic action of rhTNF in 18 h. Our data suggest that rhTNF and its muteins represent potentially useful anticancer agents; however, adequate dosing and prolonged exposure may be critical in demonstrating cytotoxicity/cytostasis. The data also show that although normal and tumor cell lines became susceptible to cytotoxicity by rhTNF and actinomycin D, combination therapy of the two agents may be possible at defined concentrations.
A panel of four monoclonal antibodies (MAbs) was generated against recombinant human tumor necrosis factor-α (rTNF). These MAbs immunoprecipitate 125I-labeled rTNF, block binding of 125I-labeled rTNF to L929 mouse fibroblasts, and neutralize in vitro cytotoxicity of rTNF and native TNF (nTNF) in the L929 cytotoxicity assay. They define distinct epitopes closely associated with the receptor binding site of rTNF. In Western analysis they bind to both monomeric and dimeric rTNF. Two MAbs recognizing distinct epitopes were used to develop a 'sandwich' enzyme immunometric assay (EIMA) to measure rTNF levels in human serum and other fluids.
Urokinase plasminogen activator (uPA) and its receptor are key components of a cell surface proteolytic cascade used by tumor cells and capillary endothelial cells for basement membrane invasion, a process required for metastasis and angiogenesis. We have cloned, expressed, and purified the epidermal growth factor-like domain of murine uPA alone and fused it to the Fc portion of human IgG as high-affinity murine urokinase receptor antagonists. These molecules are potent inhibitors of murine urokinase binding to its receptor and inhibit angiogenesis in an in vitro model of capillary tube formation in fibrin gels. In vivo, basic fibroblast growth factor-induced neovascularization and B16 melanoma growth in syngeneic mice are also substantially suppressed by these molecules. Coupled with previous studies showing inhibition of metastasis, these findings suggest that urokinase receptor antagonists may be useful therapeutically as inhibitors of tumor progression.
Peptoids differ from peptides in that peptoids are composed of N-substituted rather than alpha-carbon-substituted glycine units. In this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition. In vitro, the peptoid CHIR29498 and some of its analogues were active in the range of 3 to 12 microg/ml against a panel of gram-positive and gram-negative bacteria which included isolates which were resistant to known antibiotics. Peptoid antimicrobial activity against Staphylococcus aureus was rapid, bactericidal, and independent of protein synthesis. beta-Galactosidase and propidium iodide leakage assays indicated that the membrane is the most likely target of activity. Positional isomers of an active peptoid were also active, consistent with a mode of action, such as membrane disruption, that does not require a specific fit between the molecule and its target. In vivo, CHIR29498 protected S. aureus-infected mice in a simple infection model.
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