Enoxaparin Attenuates Mouse Colon Cancer Liver Metastases by Inhibiting Heparanase and Interferon-γ-inducible Chemokines

BACKGROUND/AIM

Low-molecular-weight heparin (LMWH) has been suggested to reduce the risk of cancer progression in both preclinical and clinical studies but the underlying mechanisms remain poorly explored. The aim of the study was to investigate the anti-metastatic role of enoxaparin, a clinically-used LMWH, in a murine model of colon cancer and to explore its underlying mechanisms.

MATERIALS AND METHODS

Using a reproducible mouse model of colon carcinomas, we assessed the capacity of enoxaparin, a LMWH, to affect tumor metastasis of colon carcinoma cell lines in mice.

RESULTS

The hepatic growth of colon carcinoma metastases was strongly inhibited by enoxaparin compared to (Ctrl) group (p=0.001). This effect was associated to an inhibition of heparanase mRNA expression and protein production both in vivo and in vitro. In addition, enoxaparin inhibited the liver and serum production of interferon gamma (Ifnγ)-inducible chemokine receptor ligands. Overexpression of heparanase prompted proliferation, migration and growth of colon carcinoma in vitro and in vivo to a point that was not affected by enoxaparin in vivo anymore.

CONCLUSION

Enoxaparin decreased liver metastases in a mouse model of colon carcinoma. These results suggest that enoxaparin may benefit patients with cancer and deserves further laboratory and clinical investigations.

Use of porous pyrolytic carbon for analytical and microscale high-performance liquid chromatographic bioseparations

Porous carbonaceous adsorbent was prepared by carbonization of saccharose in silica gel pores followed by leeching out of the silica matrix. The product of pyrolysis was then deactivated by hydrogenation. The resulting adsorbent shows intermediate sorption properties between those of the highly polar pyrolytic glassy carbon and the hydrophobic graphitized carbon. The microparticulate mesoporous carbon was examined for its use in capillary HPLC separations. The separation of selected stereoisomers in a 320 microm I.D. capillary column packed with the porous carbon particles is described and discussed. Additionally, the porous carbon filled with dextran gel was tested as a material for direct HPLC analysis of drugs in human serum.

Molded rigid polymer monoliths as separation media for capillary electrochromatography. 1. Fine control of porous properties and surface chemistry

Monolithic columns for capillary electrochromatography have been prepared within the confines of untreated fused-silica capillaries in a single step by a simple copolymerization of mixtures of butyl methacrylate, ethylene dimethacrylate, and 2-acrylamido-2-methyl-1-propane-sulfonic acid (AMPS) in the presence of a porogenic solvent. The use of these novel macroporous monoliths eliminates the need for frits, the difficulties encountered with packed capillaries, and capillary surface functionalization. Since the porous properties of the monolithic materials can be easily tailored through changes in the composition of the ternary porogenic solvent, the effects of both pore size and the percentage of sulfonic acid monomer on the efficiency and the electroosmotic flow velocity of the capillary columns could be studied independently over a broad range. A simple increase in the content of charged functionalities within the monolith leads to an expected acceleration of the flow velocity. However, increasing the pore size leads to a substantial deterioration of the efficiency of the separation. In contrast, monoliths with increasing levels of AMPS in which the pore size remains fixed due to adjustments in the composition of the porogenic solvent show no deterioration in efficiency while maintaining the same increase in flow velocity, thus producing a significant reduction in separation time. Additionally, measurements on monoliths with constant levels of AMPS but different pore sizes suggest that flow velocity may be affected by the flow resistance within the capillary column.

Molded rigid polymer monoliths as separation media for capillary electrochromatography. 2. Effect of chromatographic conditions on the separation

The effect of chromatographic conditions on the performance of monolithic poly(butyl methacrylate-co-ethylene dimethacrylate-co-2-acrylamido-2-methyl-1-propanesulfonic acid) columns in capillary electrochromatography has been studied. The flow velocity was found to be proportional to the strength of the electric field and both the pH and the composition of the mobile phase. A column efficiency of 120,000 plates/m at the optimum flow velocity of 1.5 cm/min is achieved for all the monolithic capillary columns of identical composition and porosity, regardless of their length, which varied from 30 to 120 cm. The polymeric separation medium exhibits retention and selectivity properties similar to those of typical ODS packings for reversed-phase chromatography. In addition to the "classical" use of monolithic capillary columns for the electrochromatographic separation of small molecules in reversed-phase mode, larger styrene oligomers were also separated under isocratic elution conditions. In addition, the electroosmotically driven size exclusion chromatography of polystyrene standards with molecular weights up to 10(6) has been demonstrated for the first time.

Molded rigid polymer monoliths as separation media for capillary electrochromatography

Rigid, monolithic capillary columns for reversed-phase electrochromatography have been prepared within the confines of untreated fused-silica capillaries in a single step by a simple copolymerization of ethylene dimethacrylate, butyl methacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid in the presence of a porogenic solvent. The composition of the specifically designed ternary porogenic solvent allows fine control of the porous properties of the monolithic material over a broad range. While the electroosmotic flow through these capillary columns increases with both increasing pore size of the monolith and content of charged functionalities, better chromatographic properties have been observed for monoliths with larger surface area and hydrophobicity. Using this technique, monolithic capillary columns with an efficiency higher than 120000 plates/m have been easily obtained.

Monodisperse hydrolyzed poly(glycidyl methacrylate-co-ethylene dimethacrylate) beads as a stationary phase for normal-phase HPLC

The basic characteristics of a rugged, stable, and highly efficient polymeric stationary phase for normal-phase HPLC prepared by hydrolysis of porous monodisperse poly(glycidyl methacrylate-co-ethylene dimethacrylate) beads have been studied and compared with those of bare Nucleosil silica and Nucleosil silica-diol. As a result of their overall chemical composition and the more than 10-fold larger surface coverage with hydroxyl groups, the polymer beads provide much higher retention of model solute molecules. In contrast to silica hydroxyls, all of the polymer surface diol groups are chemically equal and homogeneously distributed over all of the surface. In addition, they are less acidic than typical silanol functionalities. The exceptional selectivity of the polymeric column can be controlled by the composition of the mobile phase, as demonstrated with a broad spectrum of separations involving positional isomers of benzene derivatives, nonpolar isobutylene copolymers with minute composition differences, and hydrophilic poly(ethylene oxides) differing only in their chain length. Unlike silica phases, the properties of the polymeric stationary phrase are not affected by the presence of water in the mobile phase. As a result, repetitive gradient separations in eluents ranging in polarity from hexane through tetrahydrofuran to water can be easily accomplished.

Molded continuous poly(styrene-co-divinylbenzene) rod as a separation medium for the very fast separation of polymers. Comparison of the chromatographic properties of the monolithic rod with columns packed with porous and non-porous beads in high-performance liquid chromatography of polystyrenes

Gradient elution separations of polystyrene standards in a monolithic molded 50 x 8 mm I.D. poly(styrene-co-divinylbenzene) rod column and in 50 x 8 mm I.D. and 30 x 4.1 mm I.D. columns packed with porous and non-porous poly(styrene-co-divinylbenzene) beads has been carried out. All of these separation media differ in shape and porosity. Excellent separations of eight polystyrene standards were achieved with both the molded monolithic rod and porous beads at moderate flow-rates. However, the monolithic medium proved to be superior for high-speed separations using very steep gradients at a flow-rate of 20 ml/min. Three polystyrene standards were separated in the rod column within 4 s. The separation in the column packed with non-porous beads was poor at flow-rates of 2-8 ml/min, while higher flow-rates led to an unacceptably high back pressure.

Evaluation of microcapsule permeability via inverse size exclusion chromatography

Inverse aqueous size exclusion chromatography (SEC) was adopted to measure the permeability of microcapsules (hollow hydrogel spheres with diameter < 1 mm) using dextran molecular weight standards. Alginate/poly(L-lysine)/alginate microcapsules were chosen as a column substrate. Data from column SEC experiments were verified by kinetic studies of solute size exclusion. The permeability of tested microcapsules was modified by the reaction time with 0.05wt.% poly(L-lysine) (PLL). The exclusion limit of the microcapsules prepared at 5-min reaction time was found to be 100,000, while the microcapsules that were allowed to react with PLL for 20 min became less permeable and their exclusion limit was approximately 50,000. Based on relationships between solute size and molecular weight, the exclusion limits determined with dextrans were converted to the size and approximate molecular weight of protein presumably excluded by the capsular membrane at "ideal" conditions. The results from both column SEC and batch experiments suggest that the standard alginate/PLL/alginate capsules are permeable to immunoglobulins of IgG class. Unlike other techniques which utilize only a limited number of solutes, inverse SEC enables one to examine the capsule permeability to a homologous series of molecular weight standards. Inverse SEC also provides an opportunity to evaluate the properties of a large series of capsules directly by comparing their calibration curves. In addition, undesirable enthalpic effects in permeability studies with globular proteins as test solutes can be minimized or eliminated by using the inert molecular weight standards such as polysaccharides.

Structure and humanization of a rat monoclonal Fab to human interleukin-5

The X-ray crystal structure of a rat monoclonal Fab JES1-39D10, raised against recombinant human interleukin-5, has been determined with the use of molecular replacement techniques and refined at 2.7 A resolution by simulated annealing. The overall structure is similar to a murine Fab HyHEL-10 that is specific for hen egg white lysozyme. An interesting feature of the structure is the presence of leucine residues to support the H1 complementarity-determining region (CDR) loop. To our knowledge this is the first Fab crystal structure containing this unusual H1 loop support pattern. The activity of three humanized versions of 39D10 is explained by analysis of Fv interface residues and H1 support patterns of 39D10 and the human template HIL.

Molded monolithic rod of macroporous poly(styrene-co-divinylbenzene) as a separation medium for HPLC of synthetic polymers: on-column precipitation--redissolution chromatography as an alternative to size exclusion chromatography of styrene oligomers and polymers

A process for the separation of styrene oligomers and polymers by size and composition using a novel separation medium has been demonstrated. The process involves precipitation of the macromolecules on the molded macroporous rod columns, followed by progressive elution utilizing a simple gradient of the mobile phase. Molded macroporous rod columns are ideally suited for this technique because convection through the large pores of the rod enhances the mass transport of large analyte molecules and accelerates the separation process. Styrene oligomers and polymers are separated in a 50-mm x 8-mm-i.d. column using a solvent gradient composed of a poor solvent such as water, methanol, or acetonitrile and increasing amounts of a good solvent, tetrahydrofuran. Excellent separations are obtained, demonstrating that precipitation-redissolution can be a suitable alternate to size exclusion chromatography (SEC) of some polymers. Compared to SEC, the gradient elution separation can be achieved at higher flow rates in a much shorter time. Precipitation-redissolution with gradient elution can also be used for the separation of copolymers, for which the process is controlled not only by molecular weight but also by the composition of the copolymers.