A quantative in vivo method of analyzing human tumor-induced angiogenesis in mice using agarose microencapsulation and hemoglobin enzyme-linked immunosorbent assay

Immunomodulatory Effectiveness of Fish Oil and omega-3 Fatty Acids in Human Non-melanoma Skin Carcinoma Cells

Fish oil is composed of various fatty acids among which omega-3 fatty acids are considered as most beneficial. The effects of fish oil on the activity of a topical anticancer drug, imiquimod, and the immunomodulatory activity of omega-3 fatty acids was investigated in human basal and squamous cell carcinoma cell lines. Imiquimod-fish oil mixture exhibited higher carcinoma cell growth inhibition and immunomodulatory activity than imiquimod alone, especially against squamous cell carcinoma cells. Omega-3 fatty acids exhibited growth inhibition of both basal cell and squamous cell carcinoma cell lines and modulated the immune response. Omega-3 fatty acids of fish oil serve as inducers of interleukin-10, an anti-inflammatory cytokine, and as suppressors of interleukin-6 and tumor necrosis factor-alpha, which not only depress tumor growth but also adequately control the inflammatory side effects of imiquimod. Thus, imiquimod administration with fish oil could be beneficial for inhibition of non-melanoma skin carcinoma cells but further in vivo studies are needed to understand their role in skin cancer.

An understanding of potential and limitations of alginate/PLL microcapsules as a cell retention system for perfusion cultures

Microcapsules for high cell density culture of mammalian cells have found an increasing interest, however, the poor stability of the microcapsules and the lack of characterisation methods led to few quantitative results. Alginate-poly-L-lysine (PLL) microcapsules have been studied in detail in order to form a basis for comparison of capsules made from different polymers. Since the microcapsules can be easily retained in the bioreactor without the need for a cell separation device, high cell densities were achieved with a maximum of 4 × 10(7) cell/ml(microcapsules), corresponding to a colonisation of 5% of the internal capsule volume. Measurement of microcapsule integrity and mechanical resistance showed that alginate-PLL microcapsules are not suitable for perfusion cultures since they are very sensitive to media composition, mainly the presence of non-gelling ions that have a higher affinity for alginate than PLL and Ca(2+), leading to the leakage of PLL and Ca(2+), and to microcapsule rupture.

Neutrophil-activating protein-2- and interleukin-8-mediated angiogenesis

In this study, we investigated the anti-angiogenic potential of nitric oxide (NO) donors and anti-integrin compounds against neutrophil-activating protein-2 (NAP-2), interleukin-8 (IL-8), and basic fibroblast growth factor (FGF-2)-induced angiogenesis. In vivo, recombinant human NAP-2 and FGF-2 induce a potent and comparable angiogenic response in the chick embryo chorioallantoic membrane (CAM). We demonstrate that NO donors and anti-integrin agents are capable of abrogating either NAP-2- or FGF-2-induced angiogenesis in the CAM model. The NO donor, S-nitroso N-acetyl penicillamine (SNAP), blocked either NAP-2- or FGF-2-mediated angiogenesis in the CAM. Similarly, angiogenesis stimulated with NAP-2 or FGF-2 was blocked by antagonist of the alphavbeta3 integrin in the CAM model. However, the inhibition of NAP-2 and IL-8 by the anti-integrin compound is significantly less than the inhibition observed with FGF-2 as the angiogenic stimulus. Similarly, the ability of these mechanisms to also inhibit endothelial cell differentiation was demonstrated. Taken together, these data illustrate the involvement of multiple pathways in the mechanisms of action for the alpha-chemokine- and cytokine-mediated angiogenesis. These approaches may be a useful tool for the inhibition of angiogenesis associated with human tumor growth or with neovascular, ocular, and inflammatory diseases where chemokines and cytokines are involved.

[DDS and Me]

With the success of the human genome project, the focus of life science research has shifted to the functional and structural analyses of proteins, such as proteomics and structural genomics. These analyses of proteins including newly identified proteins are expected to contribute to the identification of therapeutically applicable proteins for various diseases. Thus, pharmaco-proteomic-based drug discovery and development for protein therapies, including gene therapy, cell therapy, and vaccine therapy, is attracting current attention. However, there is clinical difficulty in using almost all bioactive proteins, because of their very low stability and pleiotropic actions in vivo. To promote pharmaco-proteomic-based drug discovery and development, we have attempted to develop drug delivery systems (DDSs), such as the protein-drug innovation system and the optimal cell therapeutic system. In this review, we introduce our original DDSs.

Antiangiogenesis efficacy of nitric oxide donors

Angiogenesis is a complex process involving endothelial cell migration, proliferation, invasion, and tube formation. Inhibition of these processes might have implications in various angiogenesis-mediated disorders. Because nitric oxide (NO) is known to play a key role in various vascular diseases, the present study was undertaken to determine the role of NO in angiogenesis-mediated processes using the NO donor, S-nitroso N-acetyl penicillamine (SNAP) and S-nitroso N-acetyl glutathione (SNAG). The antiangiogenic efficacy of these NO donors was examined using in vivo and in vitro model systems. The in vitro studies demonstrated the ability of SNAP to inhibit cytokine fibroblast growth factor (FGF2)-stimulated tube formation and serum-induced cell proliferation. The inhibitory effect on cell proliferation by SNAP concentrations above the millimolar range was associated with significant shifts in the concentration of NO metabolites. Furthermore, using the mouse Matrigel implant model and the chick chorioallantoic membrane (CAM) models, SNAP demonstrated maximal inhibitory efficacy (85-95% inhibition) of cytokine (FGF2)-induced neovascularization in both in vivo models. SNAP and SNAG resulted in 85% inhibition of FGF2-induced neovascularization in the mouse Matrigel model when given at 5 mg/kg/day infusion in minipumps during 14 days and 87% inhibition of angiogenesis induced by FGF2 in the CAM when administered a single dose of 50 microg. Thus, NO donors might be a useful tool for the inhibition of angiogenesis associated with human tumor growth, or neovascular, ocular, and inflammatory diseases.

Technology of mammalian cell encapsulation

Entrapment of mammalian cells in physical membranes has been practiced since the early 1950s when it was originally introduced as a basic research tool. The method has since been developed based on the promise of its therapeutic usefulness in tissue transplantation. Encapsulation physically isolates a cell mass from an outside environment and aims to maintain normal cellular physiology within a desired permeability barrier. Numerous encapsulation techniques have been developed over the years. These techniques are generally classified as microencapsulation (involving small spherical vehicles and conformally coated tissues) and macroencapsulation (involving larger flat-sheet and hollow-fiber membranes). This review is intended to summarize techniques of cell encapsulation as well as methods for evaluating the performance of encapsulated cells. The techniques reviewed include microencapsulation with polyelectrolyte complexation emphasizing alginate-polylysine capsules, thermoreversible gelation with agarose as a prototype system, interfacial precipitation and interfacial polymerization, as well as the technology of flat sheet and hollow fiber-based macroencapsulation. Four aspects of encapsulated cells that are critical for the success of the technology, namely the capsule permeability, mechanical properties, immune protection and biocompatibility, have been singled out and methods to evaluate these properties were summarized. Finally, speculations regarding future directions of cell encapsulation research and device development are included from the authors' perspective.

Evaluation of angiogenic inhibitors with an in vivo quantitative angiogenesis method using agarose microencapsulation and mouse hemoglobin enzyme-linked immunosorbent assay

In the present work, using a previously reported in vivo quantitative tumor-angiogenesis model, we attempted to ascertain whether this animal model is suitable for practical use in monitoring inhibitors of tumor angiogenesis. Mouse sarcoma-180 cells, human A431 cells or rat C6 cells microencapsulated in agarose beads were implanted s.c. into C57BL/6 mice. The level of blood vessel induction at the agarose pellet site was evaluated using mouse hemoglobin enzyme-linked immunosorbent assay on day 10 after implantation. Hydrocortisone, tetrahydro-S, medroxyprogesterone acetate, pentosan polysulfate and suramin inhibited blood vessel growth in our in vivo tumor-angiogenesis assay system, and heparin enhanced the antiangiogenic effects of hydrocortisone and tetrahydro-S. These results are almost entirely consistent with those observed in common assay systems, and suggest that this method may be useful for the identification and quantitative evaluation of inhibitors of tumor angiogenesis.

Selective enhancement by tumor necrosis factor-alpha of vascular permeability of new blood vessels induced with agarose hydrogel-entrapped Meth-A fibrosarcoma cells

We have previously developed a simple and quantitative method for assessment of in vivo tumor cell-induced angiogenesis by means of microencapsulation of tumor cells in agarose hydrogel and mouse hemoglobin ELISA (mHb-ELISA). In this article, we report that the new blood vessels induced with agarose-encapsulated tumor cells have the same sensitivity to tumor necrosis factor-alpha (TNF-alpha) as the original solid-tumor vessels. Agarose beads (average diameter = 200 microns), in which Meth-A fibrosarcoma cells were microencapsulated, were subcutaneously implanted in non-syngeneic ddY mice. Ten days later, extensive angiogenesis was observed on the implanted sites of Meth-A agarose heads, whereas no new blood vessels were induced with cell-free agarose heads. The vascular permeability of the new blood vessels induced with agarose-microencapsulated Meth-A cells was selectively and significantly enhanced by the i.v. injection of TNF-alpha, and it reached the maximum level at 2 h after the injection of TNF-alpha. At 4 h after the injection of TNF-alpha, the vascular permeability was reduced to the basal level. This permeability profile in Meth-A agarose beads in ddY mice is very similar to that in Meth-A solid tumor in syngeneic BALB/c mice. On the other hand, TNF-alpha-treatment did not affect the vascular permeability of other normal tissues or inflammatory tissue in ddY mice. These results strongly suggest that the new blood vessels induced with agarose-microencapsulated tumor cells have the specific characteristics of tumor vessels. Our in vivo angiogenesis assay system should be useful not only to screen anti-angiogenetic agents, but also to elucidate the mechanism of tumor angiogenesis.