The Macrophage Inhibitor CNI-1493 Blocks Metastasis in a Mouse Model of Ewing Sarcoma through Inhibition of Extravasation

Metastatic Ewing Sarcoma carries a poor prognosis, and novel therapeutics to prevent and treat metastatic disease are greatly needed. Recent evidence demonstrates that tumor-associated macrophages in Ewing Sarcoma are associated with more advanced disease. While some macrophage phenotypes (M1) exhibit anti-tumor activity, distinct phenotypes (M2) may contribute to malignant progression and metastasis. In this study, we show that M2 macrophages promote Ewing Sarcoma invasion and extravasation, pointing to a potential target of anti-metastatic therapy. CNI-1493 is a selective inhibitor of macrophage function and has shown to be safe in clinical trials as an anti-inflammatory agent. In a xenograft mouse model of metastatic Ewing Sarcoma, CNI-1493 treatment dramatically reduces metastatic tumor burden. Furthermore, metastases in treated animals have a less invasive morphology. We show in vitro that CNI-1493 decreases M2-stimulated Ewing Sarcoma tumor cell invasion and extravasation, offering a functional mechanism through which CNI-1493 attenuates metastasis. These data indicate that CNI-1493 may be a safe and effective adjuvant agent for the prevention and treatment of metastatic Ewing Sarcoma.     

The dark-colour-inducing neurohormone of locusts in relation to an albino mutant of Schistocerca gregaria

In the albino mutant of an Okinawa strain of Locusta migratoria (L.) (Orthoptera: Acrididae), albinism is caused by the absence of the dark‐colour‐inducing neurohormone (DCIN), which is present in the corpora cardiaca (CC) of normally coloured phenotypes. This study tests whether the absence of DCIN is responsible for albinism in an albino mutant of another locust, Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae). This seemed feasible because a single Mendelian unit controls albinism in both species. However, implantation of CC, or injection of an extract of CC, from albino donors of S. gregaria, induce dark coloration in crowded nymph recipients of the Okinawa albino mutant of L. migratoria, as effectively as do implanted CC, or injections of extract of CC, from normal phenotype donors of S. gregaria. Therefore, DCIN is present in the albino mutant of S. gregaria, and consequently, the albinism in this mutant is not caused by its absence. Implantation of CC, or injection of extracts of CC, from albino donors of S. gregaria to conspecific albino nymphs does not induce darkening. Only extremely high doses of synthetic DCIN injected into albino nymphs of S. gregaria are effective, inducing some darkening. The dose to induce such darkening in albino nymphs of S. gregaria is 50 nmol, ≈ 5 × 10⁶ times higher than that (10 femtomol) needed to induce equivalent darkening in nymphs of the Okinawa albinos of L. migratoria. The results are discussed and some possible explanations of the observed effects outlined.     

The chemical and kinetic consequences of the modification of papain by N-bromosuccinimide.

Nonactivated papain was treated with N-bromosuccinimide at pH 4.75. The N-bromosuccinimide-modified enzyme was characterized by (1) the change in absorbance at 280 nm, (2) amino acid analysis, (3) separate chemical determinations of tryptophan and tyrosine (4) difference spectroscopy, and (5) an N-terminal residue determination. It is concluded that N-bromosuccinimide in sevenfold molar excess oxidizes one tryptophan and two to three tyrosine residues per molecule of nonactivated papain, without causing peptide chain cleavage. Kinetic studies with several substrates and competitive peptide inhibitors were performed at pH6 using the N-bromosuccinimide-modified papain. In addition, the kinetics of the modified enzyme with the substrate alpha-N-benzoyl-L-arginine ethl ester were studied in the region of pH 3.5-9.0. All substrates (and inhibitors) test, with the exception of alpha-N-benzyoyl-L-arginine p-nitroanilide, displayed approximately a two fold decrease in both kcat and Km (or Ki), relative to the native enzyme. It is concluded that the key tryptophan residue which is probably Trp-177.     

Membrane excitability expressed in human neuroblastoma cell hybrids

The voltage-sensitive Na+ channel is responsible for the action potential of membrane electrical excitability in neuronal tissue. Three methods were used to demonstrate the presence of neurotoxin-responsive Na+ channels in two hybrid cell lines resulting from the fusion of excitable human neuroblastoma cells with mouse fibroblasts. Only one of the two electrically active hybrid cell lines maintained the sensitivity of the neuroblastoma parent to tetrodotoxin (TTX). The other hybrid, although electrically active, was not responsive to TTX or scorpion venom. Comparisons of the patterns of expression of membrane excitability and of chromosome complements in these human neuroblastoma cell hybrids suggest that the phenotype of membrane excitability is composed of genetically distinct elements.     

Spontaneous asymmetric circling behavior in hemi-parkinsonism; a human equivalent of the lesioned-circling rodent behavior

When induced experimentally in rodents, hemispheric asymmetry in basal ganglia dopamine results in spontaneous asymmetric circling toward the hemisphere with the lower level of dopamine. A similar asymmetry has long been thought to exist in the brains of hemi-Parkinsonian patients. Using an electronic turn counter, we demonstrated that, like unilaterally lesioned rats, and without being aware of it, five ambulating outpatients with hemi-Parkinson's disease exhibit spontaneous rotation toward the hemisphere containing less striatal dopaminergic activity.     

Surface haemagglutinating activity of Pseudomonas aeruginosa

Intact cells of several strains of Pseudomonas aeruginosa agglutinate papain-treated human erythrocytes. The agglutinating activity appears to reside in the surface layers of the bacterium-Pseudomonas surface haemagglutinin. This activity does not correlate with the existence of the internal PA-I and PA-II lectins, the presence of fimbriae or adherence to human buccal epithelial cells. Disruption of the bacterial cells by sonication abolishes their haemagglutinating activity. The intact cells of P. aeruginosa are also able to agglutinate rabbit, chicken, dog, guinea pig and sheep erythrocytes. This activity is generally higher with papain-treated erythrocytes, except those of rabbit in which lower haemagglutinating activity is observed after papain treatment. Optimal conditions for the haemagglutination are 37 degrees C and pH 6-7. Simple sugars do not inhibit, while fetuin and hydrophobic amino acids inhibit this activity. Exposure of the bacterial cells to proteolytic enzymes, EDTA or denaturating conditions abolish the haemagglutinating activity. These results indicate that the surface haemagglutinin is a protein which agglutinates red blood cells via hydrophobic interactions.     

NIH 3T3 cells transfected with human tumor DNA lose the transformed phenotype when treated with swainsonine

Phenotypic expression of transformation was inhibited by swainsonine at concentrations which affect the late stages of glycoprotein processing but not growth of cells. In the presence of swainsonine, NIH 3T3 fibroblasts transfected with human tumor DNA (al-l) no longer grew in soft agar or expressed complex type oligosaccharides characteristic of transformed cells. Thus, it appears that glycoproteins with fully processed oligosaccharides are necessary for the maintenance of the transformed phenotype in these cells.