Stimulation of TNF-alpha production by 2-(1-adamantylamino)-6-methylpyridine (AdAMP) - a novel immunomodulator with potential application in tumour immunotherapy.

The immunomodulatory effects of a recently synthesized adamantane derivative of aminopyridine - 2-(1-adamantylamino)-6-methylpyridine (AdAMP) - were tested on normal and neoplastic cells in vitro. When incubated with TNF-alpha gene-transduced mouse melanoma cells (B78/TNF), AdAMP significantly enhanced basal production of TNF-alpha by these cells, both by "high" and "moderate" TNF-alpha-producer cells. A similar TNF-alpha production-enhancing effect was observed in cultures of human ovarian carcinoma cells (CAOV1) which spontaneously produce TNF-alpha but not in cultures of tumour cells incapable of TNF-alpha secretion.

IL-12 or IL-15, unlike IL-2, does not interact with histamine in augmenting cytotoxicity of splenocytes against melanoma cells and YAC-1 cells.

It has been suggested that histamine by its ability to downregulate the production of macrophage-derived reactive oxygen species might effectively potentiate the cytotoxic activity of cytokine-stimulated NK cells. Histamine thus reverses negative regulation of NK cells treated with IL-2 and IFN-alpha in the presence of macrophages. We confirm that histamine potently enhances cytotoxic activity of IL-2-stimulated NK cell-enriched splenocytes admixed with macrophages against B16F10 melanoma cells and YAC-1 cells.

Antitumor activity of tributyrin in murine melanoma model.

Butyric acid has been known to inhibit growth and to induce differentiation of a variety of tumor cells. Butyrate-treated tumor cells have also been observed to undergo apoptosis. Although butyrate compounds have demonstrated antitumor activity in murine tumor models and have already been admitted to clinical trials in tumor patients, the exact mechanism of their antitumor effects has not been elucidated.

Lovastatin and simvastatin are modulators of the proteasome.

Lovastatin and simvastatin are HMG-CoA reductase inhibitors widely used as antihyperlipidemic drugs, which also display antiproliferative properties. In the present paper, we provide evidence that both lovastatin and simvastatin are modulators of the purified bovine pituitary 20 S proteasome, since they mildly stimulate the chymotrypsin-like activity and inhibit the peptidylglutamylpeptide hydrolyzing activity without interfering with the trypsin-like activity. However, those effects are only observed when the closed ring forms of the drugs are used, while the opened ring form of lovastatin acts as a mild inhibitor of the chymotrypsin like activity.