Hyaluronan Synthase Elevation in Metastatic Prostate Carcinoma Cells Correlates with Hyaluronan Surface Retention, a Prerequisite for Rapid Adhesion to Bone Marrow Endothelial Cells

Bone marrow is the primary site of metastasis in patients with advanced stage prostate cancer. Prostate carcinoma cells metastasizing to bone must initially adhere to endothelial cells in the bone marrow sinusoids. In this report, we have modeled that interaction in vitro using two bone marrow endothelial cell (BMEC) lines and four prostate adenocarcinoma cell lines to investigate the adhesion mechanism. Highly metastatic PC3 and PC3M-LN4 cells were found to adhere rapidly and specifically (70-90%) to BMEC-1 and trHBMEC bone marrow endothelial cells, but not to human umbilical vein endothelial cells (15-25%). Specific adhesion to BMEC-1 and trHBMEC was dependent upon the presence of a hyaluronan (HA) pericellular matrix assembled on the prostate carcinoma cells. DU145 and LNCaP cells were only weakly adherent and retained no cell surface HA. Maximal BMEC adhesion and RA encapsulation were associated with high levels of HA synthesis by the prostate carcinoma cells. Up-regulation of HA synthase isoforms Has2 and Has3 relative to levels expressed by normal prostate corresponded to elevated HA synthesis and avid BMEC adhesion. These results support a model in which tumor cells with up-regulated HA synthase expression assemble a cell surface hyaluronan matrix that promotes adhesion to bone marrow endothelial cells. This interaction could contribute to preferential bone metastasis by prostate carcinoma cells

The effect of proteoglycans on the formation of fibrils from collagen solutions

The precipitation of collagen fibrils from solutions at 37 [deg]C and approximately physiological pH and ionic strength is retarded markedly in the presence of small amounts of proteoglycan monomer (PGS), proteoglycan aggregate (PGC), reduced and alkylated PGS, or cyanogen bromide-cleavage products of PGS. The polysaccharide-peptide fragments produced from PGS with papain, trypsin, cathepsin D, or the protein core obtained by the digestion of PGS with chondroitinase ABC are ineffective in this regard. In the presence of the materials which affected the rate of precipitation of the collagen fibrils, the specific absorbance, [Delta]Asp, of the collagen gels was directly related to specific retardation, Rsp, when the ratio of proteoglycan to collagen was less than 25 [mu]g/mg, suggesting that the size and/or organization of the fibrils in the gels was dependent on the presence of proteoglycans. PGS binds to collagen if it is present in the solution before the collagen fibrils form and at a maximum of about 1 molecule of PGS for every 25-30 molecules of collagen. Although the protein core of PGS does not retard fibrillogenesis, it does bind to collagen and does so even in the presence of PGS. The data support the thesis that the organization of collagen fibrils in tissues may be related to amounts and kinds of proteoglycans in the tissues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22193/1/0000624.pd

Mactinin, a fragment of cytoskeletal α-actinin, is a novel inducer of heat shock protein (Hsp)-90 mediated monocyte activation

<p>Abstract</p> <p>Background</p> <p>Monocytes, their progeny such as dendritic cells and osteoclasts and products including tumor necrosis factor (TNF)-α, interleukin (IL)-1α and IL-1β play important roles in cancer, inflammation, immune response and atherosclerosis. We previously showed that mactinin, a degradative fragment of the cytoskeletal protein α-actinin, is present at sites of monocytic activation in vivo, has chemotactic activity for monocytes and promotes monocyte/macrophage maturation. We therefore sought to determine the mechanism by which mactinin stimulates monocytes.</p> <p>Results</p> <p>Radiolabeled mactinin bound to a heterocomplex on monocytes comprised of at least 3 proteins of molecular weight 88 kD, 79 kD and 68 kD. Affinity purification, mass spectroscopy and Western immunoblotting identified heat shock protein (Hsp)-90 as the 88 kD component of this complex. Hsp90 was responsible for mediating the functional effects of mactinin on monocytes, since Hsp90 inhibitors (geldanamycin and its analogues 17-allylamino-17-demethoxygeldanamycin [17-AAG] and 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin [17-DMAG]) almost completely abrogated the stimulatory activity of mactinin on monocytes (production of the pro-inflammatory cytokines IL-1α, IL-1β and TNF-α, as well as monocyte chemotaxis).</p> <p>Conclusion</p> <p>Mactinin is a novel inducer of Hsp90 activity on monocytes and may serve to perpetuate and augment monocytic activation, thereby functioning as a "matrikine." Blockage of this function of mactinin may be useful in diseases where monocyte/macrophage activation and/or Hsp90 activity are detrimental.</p

Metabolism of ovomucoid by the developing chick embryo This work was supported by Grant AM-10531 from the National Institute of Arthritis, Metabolic and Digestive Diseases, National Institutes of Health.

A glycoprotein resembling ovomucoid was purified from chorioallantoic membranes of 12.5 day chick embryos by a sequential procedure involving zinc chloride precipitation, hydroxylapatite chromatography, and ion exchange chromatography on DEAE- and CM-cellulose. The resulting preparation was homogeneous as indicated by polyacrylamide gel electrophoresis at 3 pH values, isoelectric focusing, ultracentrifugation, and immunochemical analysis. The purified material had an isoelectric point of 4.8, molecular weight of 29,500 and contained 1.6 moles of galactose, 7.7 moles of mannose, 22.8 moles of N -acetylglucosamine and 0.4 mole of glucose per mole of protein. The ovomucoid fraction inhibited bovine trypsin, forming a 1 to 1 complex on a molar basis, and elicited a positive anaphylactoid response in albino rats at levels as low as 0.5 Μg. A specific ovomucoid antiserum was obtained from rabbits that allowed investigation of the mobilization and metabolism of ovomucoid in the developing chick embryo. These studies revealed that between days 12 and 13 of embryo development a progressive migration of ovomucoid occurs from the albumin sac to the amnionic sac. The glycoprotein is then swallowed and transported through the gut to the yolk sac, where it is catabolized by proteases and glycosidases contained in the yolk sac membrane. Between day 12 of embryo development and day 7 after hatching, ovomucoid appeared in the serum of the chick and reached a maximum value of 2.4 mg % on day 18 of embryo development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38074/1/1401890203_ftp.pd