concanavalin-a and mevastatin

Combinations of cellular immune-based therapies with chemotherapy and other antitumour agents may be of significant clinical benefit in the treatment of many forms of cancer. Gamma delta (gammadelta) T cells are of particular interest for use in such combined therapies due to their potent antitumour cytotoxicity and relative ease of generation in vitro. Here, we demonstrate high levels of cytotoxicity against solid tumour-derived cell lines with combination treatment utilizing Vgamma9Vdelta2 T cells, chemotherapeutic agents and the bisphosphonate, zoledronate. Pre-treatment with low concentrations of chemotherapeutic agents or zoledronate sensitized tumour cells to rapid killing by Vgamma9Vdelta2 T cells with levels of cytotoxicity approaching 90%. In addition, zoledronate enhanced the chemotherapy-induced sensitization of tumour cells to Vgamma9Vdelta2 T cell cytotoxicity resulting in almost 100% lysis of tumour targets in some cases. Vgamma9Vdelta2 T cell cytotoxicity was mediated by perforin following TCR-dependent and isoprenoid-mediated recognition of tumour cells. Production of IFN-gamma by Vgamma9Vdelta2 T cells was also induced after exposure to sensitized targets. We conclude that administration of Vgamma9Vdelta2 T cells at suitable intervals after chemotherapy and zoledronate may substantially increase antitumour activities in a range of malignancies.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Burkitt Lymphoma; Carcinoma; Cell Line, Tumor; Cisplatin; Colorectal Neoplasms; Concanavalin A; Cytotoxicity, Immunologic; Diphosphonates; Doxorubicin; Drug Screening Assays, Antitumor; Drug Synergism; Etoposide; Female; Genes, T-Cell Receptor delta; Genes, T-Cell Receptor gamma; Humans; Imidazoles; Interferon-gamma; Lovastatin; Lung Neoplasms; Male; Membrane Glycoproteins; Neoplasms; Perforin; Pore Forming Cytotoxic Proteins; Prostatic Neoplasms; Receptors, Antigen, T-Cell, gamma-delta; T-Lymphocyte Subsets; Urinary Bladder Neoplasms; Vincristine; Zoledronic Acid

The effect of mevastatin and mevinolin on the fusion of L6 myoblasts was studied. Both compounds were present inhibitors of myoblast fusion at concentrations as low as 0.25 microM, but fusion was restored when the inhibitors were removed. Both compounds resulted in decreased binding of conA and WGA to cell surface oligosaccharides showing they were causing a reduction in N-linked cell surface glycoproteins. There was a reduction in creatine phosphokinase activities in the presence of both compounds showing that they were affecting biochemical differentiation. The presence of both compounds inhibited the incorporation of labeled mannose from GDP-mannose into lipid-sugar and N-linked glycoprotein, but the inhibition was reversed by addition of exogenous dolichol phosphate to the incorporation mixture. The main conclusion from these studies is that mevinolin and mevastatin are inhibiting myoblast fusion by affecting the synthesis of fusogenic cell surface N-linked glycoproteins probably by affecting the synthesis of dolichol phosphate containing oligosaccharides that are required as intermediates in N-linked glycoprotein biosynthesis.

Topics: Animals; Cell Fusion; Cell Line; Concanavalin A; Creatine Kinase; Glycoproteins; Lovastatin; Mannose; Muscles; Rats; Receptors, Mitogen; Wheat Germ Agglutinins

Topics: Acetates; Adult; B-Lymphocytes; Cells, Cultured; Cholesterol; Concanavalin A; DNA; Female; Humans; Hydroxycholesterols; Leukemia, Hairy Cell; Lovastatin; Male; Mevalonic Acid; Middle Aged; Naphthalenes

Concanavalin A induction of DNA synthesis in mouse spleen lymphocytes cultured in serum-free medium was shown to be very sensitive to inhibition by compactin (ML-236B), a specific competitive inhibitor of hydroxymethylglutaryl-CoA reductase. As low as 0.1 microM compactin could give 98% inhibition of mitogen induction of a 5.10(6) cells/ml culture. This inhibition could be reversed completely by addition of exogenous mevalonate, but could not be reversed by either exogenous cholesterol or isopentenyladenine. Oxygenated sterol inhibition of mitogen-induced DNA synthesis could be reversed by cholesterol or by mevalonate, whereas cyclic AMP inhibition could not be reversed by either compound. These results suggest that endogenous cholesterol production is a necessary but not sufficient factor co-ordinated with mitogen-induced DNA synthesis, and that the presence of some additional product of mevalonate metabolism is involved also. Isopentenyladenine, though, did not have as significant effect of alleviating any of the above inhibitions. Since mevalonate could not relieve cyclic AMP inhibition, but could overcome compactin inhibition, cyclic AMP inhibition cannot be explained as due only to blockage of mevalonate production.

Topics: Animals; Bucladesine; Cholesterol; Concanavalin A; Cricetinae; DNA Replication; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lovastatin; Lymphocyte Activation; Mevalonic Acid; Mice; Naphthalenes

Mevalonic acid (5 x 10(-4)-1 x 10(-2) M) stimulates DNA synthesis, morphologic transformation and cell cycling in peripheral blood human lymphocytes. Other organic acid anions which serve as cholesterol and mevalonate precursors are devoid of such effects. Both ML-236B and 25-hydroxycholesterol, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, inhibit concanavalin A-induced lymphocyte transformation, but only the inhibition by ML-236B can be overcome by exogenous mevalonate. In contrast, only 25-hydroxycholesterol inhibits mevalonate-induced lymphocyte DNA synthesis. The effects of mevalonic acid on lymphocytes cannot be reproduced by isopentenyl adenine or isopentenyl adenosine. Unregulated endogenous cellular synthesis of mevalonic acid may contribute to uncontrolled growth in certain malignant cell lines.

Topics: Concanavalin A; DNA; Humans; Hydroxycholesterols; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lovastatin; Lymphocyte Activation; Lymphocytes; Mevalonic Acid; Naphthalenes

Topics: Cholesterol; Concanavalin A; Humans; Ketocholesterols; Lovastatin; Lymphocyte Activation; Mevalonic Acid; Mitogens; Naphthalenes; Phytohemagglutinins; Pokeweed Mitogens; Sterols; T-Lymphocytes; Time Factors