Ultraviolet B radiation mediated generation of Platelet-activating factor agonists augments melanoma tumor growth

poster abstractPlatelet-activating factor (1-alkyl-2-acetyl-glycerophosphocholine; PAF) is a potent lipid mediator with diverse activities. Our previous studies have demonstrated that oxidized glycerophosphocholines (OxGPCs) that act as agonists for the Platelet-activating factor receptor (PAF-R) mediate ultraviolet B radiation (UVB) induced systemic immunosuppression in a process involving IL-10. However, the exact role of UVB-mediated systemic immunosuppression in pathophysiological processes remains unclear. The current studies sought to define whether UVB-induced systemic immunosuppression could modulate experimental murine melanoma tumor growth. Using a murine UVB model of systemic immunosuppression, we demonstrate that UVB exposure to a remote site from skin implanted with subcutaneous B16F10 melanoma results in enhanced tumor growth in C57BL/6 (wild-type) mice but not in PAF-R-deficient mice. We further show that intraperitoneal injection of the PAF agonist carbamoylPAF (CPAF) mimicked the UVB effect. Interestingly, neutralizing antibody against IL-10 blocked both CPAF- and UVB-mediated augmentation of B16F10 tumor growth. The next studies were designed to define whether the PAF-R effect was due to direct effects on B16F10 cells. Of note, B16F10 cells lack functional PAF-R expression. To address this question, we first generated PAF-R expressing B16F10 (B16-PAFR) and its vector control B16-MSCV cells by retroviral transduction and confirmed the presence of PAF-R in B16-PAF-R cells by intracellular Ca2+ flux in response to CPAF and qRT-PCR. Transplantation of B16-PAFR cells into mice did not result in an increased rate of tumor growth over control B16-MSCV cells either alone, or in response to UVB or CPAF. These studies provide a novel unreported effect of UVB-mediated PAF agonists, namely, that they can augment melanoma tumor growth via IL-10

The inshore fish faunas over soft substrates and reefs on the tropical west coast of Australia differ and change with latitude and bioregion

Aim To test the following hypotheses regarding ichthyofaunal compositions along an extensive tropical coastline. The compositions over soft substrates and reefs: (1) consistently differ markedly; (2) change progressively with latitude and temperature through sequential changes in the abundances of certain species; and (3) vary among bioregions, as those regions differ markedly in their environmental characteristics. Location Tropical north-western Australia. Methods Similarity matrices, derived from percentage contributions of each fish species to catches obtained over soft substrates by trawling and over reefs by trapping at seven regularly spaced sites along 1500 km of coast, were subjected to cluster analysis, non-metric multidimensional scaling ordination and associated tests. Results In total, 361 species were obtained by trawling and trapping along the tropical coast of north-western Australia (NWA). Only 56 species were recorded over both soft substrates and reefs, whereas 229 and 76 species were caught exclusively over soft substrates and reefs, respectively. The Leiognathidae, Carangidae and Terapontidae contributed most individuals (62.2%) to catches over soft substrates, whereas the Lethrinidae and Lutjanidae dominated those over reefs (81.9%). The species compositions in both habitats were related to latitude and water temperature. Ichthyofaunal compositions in the Kimberley region differed markedly from those in the Canning/Pilbara regions further south, which, in turn, each had distinct characters. The vast majority of species found over both habitats also occur in the Pacific Ocean to the north. Main conclusions The most important fish families over soft substrates and reefs in inshore marine waters of tropical NWA differ markedly. The ichthyofaunal compositions of both habitats undergo similar patterns of progressive change with latitude, due to site-staggered changes in the relative abundances of key fish species in their respective habitats. Ichthyofaunal composition in both habitats was found to be influenced by water temperature. The latitudinal trends exhibited by species composition are overlaid on a strong bioregional effect, reflecting the influence of the very different environmental conditions in those bioregions, which include marked differences in such factors as tidal regime, turbidity and whether mangroves are nearby. The important contribution of species with a Pacific affinity was presumably facilitated by the polewards-flowing Indonesian Throughflow, which links the Pacific Ocean with waters bordering the NWA coast