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.     

Birth seasonality,photoperiod, and social change in the Central Canadian Arctic

Birth seasonally at high latitudes is a complex phenomenon which is undoubtedly affected by a subtle interaction between environmental rhythmicity (most notably in photoperiod and temperature) and cultural adaption. There is intriguing evidence that human gonadotrophic activity (and hence fertility) may be affected by seasonal fluctuations in light intensity and duration. Nevertheless, cultural factors are important insofar as they mediate between environmental rhythmicity and human fertility/birth patterns. This article examines the distribution of births over several decades in an Inuit community located 300 miles north of the Arctic Circle. Several shifts in birth seasonality are noted, the most significant of which is a dramatic shift from pronounced seasonality in the 1970s to non-seasonality in the 1980s. Longitudinal ethnographic fieldwork has allowed an examination of social and economic changes accounting for the rather sudden disappearance of birth seasonality. These include increasing reliance upon wage employment and social assistance, decreased dependence upon subsistence hunting and trapping, changing attitudes on the part of young people entering their prime reproductive years, and the introduction of television, radio, and southern-style recreational activities.     

INTESTINAL TRANSPORT OF ANTIBODIES IN THE NEWBORN RAT

Evidence has been reported that the proximal small intestine of the neonatal rat selectively transports antibodies into the circulation. This study describes the morphology of the absorptive epithelial cells in this region of the intestine and their transport of several immunoglobulin tracers: ferritin-conjugated immunoglobulins (IgG-Ft) and antiperoxidase antibodies. Cells exposed to rat IgG-Ft bound the tracer on the membrane of tubular invaginations of the apical cell surface. Tubular and coated vesicles within the cell also contained the tracer, as did the intercellular spaces. Uptake of tracer was highly selective and occurred only with rat or cow IgG-Ft; when cells were exposed to chicken IgG-Ft, ferritin-conjugated bovine serum albumin, or free ferritin, tracer did not enter the cell or appear in the intercellular spaces. Experiments with rat and chicken antiperoxidase showed a similar selective uptake and transport of only the homologous antibody. When cells from the distal small intestine were exposed to the tracers, all tracers were absorbed nonselectively but none were released from the cells. Cells from the proximal small intestine of the 22-day-old rat failed to absorb even rat IgG-Ft. A model is presented for selective antibody transport in proximal cells of the neonatal rat in which antibodies are selectively absorbed at the apical cell surface by pinocytosis within tubular vesicles. The antibodies are then transferred to the intercellular space within coated vesicles. Distal cells function only to digest proteins nonselectively.     

Identification of the coding region for the putidaredoxin reductase gene from the plasmid of Pseudomonas putida

The first 12 NH₂-terminal amino acids of the Pseudomonas putida putidaredoxin reductase were shown to be Met-Asn-Ala-Asn-Asp-Asn-Val-Val-Ile-Val-Gly-Thr. Comparison of these data with the DNA sequence of the BamHI-HindIII 197-base fragment derived from the PstI 2.2-kb fragment obtained from the P. putida plasmid showed that the putidaredoxin reductase gene was downstream from the cytochrome P-450 gene and the intergenic region had the 24-nucleotide sequence TAAACACATGGGAGTGCGTGCTAA. The Shine-Dalgarno sequence GGAG was detected in this region. The initiating triplet for the reductase gene was GTG, which normally codes for valine, but in the initiating codon position codes for methionine. From the amino acid sequence and X-ray data comparisons with other flavoproteins, what appears to be the AMP binding region of the FAD can be recognized in the NH₂-terminal portion of the reductase involving residues 5–35.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

Species-area curves and estimates of total species richness in an old-field chronosequence

Average species-area curves were generated for vascular plants in 20 old-fields that were sampled in 1983, 1989, and 1994. These curves were fit with a saturating function to estimate total species richness for each old-field. Additional estimates of total species richness were generated by fitting the same saturating function to subsets of the species area curves and with a first-order jackknife procedure. Estimates of total species richness were strongly correlated with observed species richness. There was limited evidence suggesting that greater sampling was necessary to identify the same proportion of species in older, more species-rich old-fields.     

Mlc1p Is a Light Chain for the Unconventional Myosin Myo2p in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, the unconventional myosin Myo2p is of fundamental importance in polarized growth. We explore the role of the neck region and its associated light chains in regulating Myo2p function. Surprisingly, we find that precise deletion of the six IQ sites in the neck region results in a myosin, Myo2-Δ6IQp, that can support the growth of a yeast strain at 90% the rate of a wild-type isogenic strain. We exploit this mutant in a characterization of the light chains of Myo2p. First, we demonstrate that the localization of calmodulin to sites of polarized growth largely depends on the IQ sites in the neck of Myo2p. Second, we demonstrate that a previously uncharacterized protein, Mlc1p, is a myosin light chain of Myo2p. MLC1 (YGL106w) is an essential gene that exhibits haploinsufficiency. Reduced levels of MYO2 overcome the haploinsufficiency of MLC1. The mutant MYO2-Δ6IQ is able to suppress haploinsufficiency but not deletion of MLC1. We used a modified gel overlay assay to demonstrate a direct interaction between Mlc1p and the neck of Myo2p. Overexpression of MYO2 is toxic, causing a severe decrease in growth rate. When MYO2 is overexpressed, Myo2p is fourfold less stable than in a wild-type strain. High copies of MLC1 completely overcome the growth defects and increase the stability of Myo2p. Our results suggest that Mlc1p is responsible for stabilizing this myosin by binding to the neck region.