Effect of auranofin on eicosanoids and protein kinase C in human neutrophils

Lithium Preparations in Psychiatry, Addiction Medicine and Neurology. Part II. Biochemical Mechanisms of Its Action

Lithium is the first and the lightest in the series of alkali metals, to which, in addition to lithium, two very biologically important elements – sodium and potassium, as well as trace elements rubidium and cesium, belong. Despite its formal affiliation to the group of alkali metals, lithium, like many other chemical elements of the «atypical» second period of the periodic table (for example, boron), is more similar in its chemical properties not to its counterparts in the group, but to its «diagonal brother» – magnesium. As we will show in this article, the diagonal chemical similarity between lithium and magnesium is of great importance for understanding the mechanisms of its intracellular biochemical action. At the same time, the intragroup chemical similarity of lithium with sodium and potassium is more important for understanding the mechanisms of its absorption, its distribution in the body and its excretion. Despite the 70 years that have passed since John Cade’s discovery of the antimanic effect of lithium, the mechanisms of its therapeutic action are still not completely understood. In the end, it turns out that the mechanism of the therapeutic action of lithium is extremely complex, multicomponent, unique and not imitable. Certain aspects of the mechanism of its action may be compatible with the mechanisms of action of other mood stabilizers, or with the mechanisms of action of so-called «lithium-mimetics», such as ebselen. However, no other drug to date failed to fully reproduce the biochemical effect of lithium on the body.

CUSP9* treatment protocol for recurrent glioblastoma: aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, ritonavir, sertraline augmenting continuous low dose temozolomide

CUSP9 treatment protocol for recurrent glioblastoma was published one year ago. We now present a slight modification, designated CUSP9*. CUSP9* drugs--aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, sertraline, ritonavir, are all widely approved by regulatory authorities, marketed for non-cancer indications. Each drug inhibits one or more important growth-enhancing pathways used by glioblastoma. By blocking survival paths, the aim is to render temozolomide, the current standard cytotoxic drug used in primary glioblastoma treatment, more effective. Although esthetically unpleasing to use so many drugs at once, the closely similar drugs of the original CUSP9 used together have been well-tolerated when given on a compassionate-use basis in the cases that have come to our attention so far. We expect similarly good tolerability for CUSP9*. The combined action of this suite of drugs blocks signaling at, or the activity of, AKT phosphorylation, aldehyde dehydrogenase, angiotensin converting enzyme, carbonic anhydrase -2,- 9, -12, cyclooxygenase-1 and -2, cathepsin B, Hedgehog, interleukin-6, 5-lipoxygenase, matrix metalloproteinase -2 and -9, mammalian target of rapamycin, neurokinin-1, p-gp efflux pump, thioredoxin reductase, tissue factor, 20 kDa translationally controlled tumor protein, and vascular endothelial growth factor. We believe that given the current prognosis after a glioblastoma has recurred, a trial of CUSP9* is warranted.

The mechanisms of action of disease-modifying antirheumatic drugs: a review with emphasis on macrophage signal transduction and the induction of proinflammatory cytokines

1. Rheumatoid arthritis (RA) is probably the most common source of treatable disability. A major problem in modern rheumatology is that the mechanism(s) of action of the currently used disease-modifying antirheumatic drugs (DMARDs) remain unclear. Many of these drugs entered rheumatology mainly through clinical intuition and have been used for decades. 2. The former T-cell-centered paradigm of rheumatoid inflammation has given way to a model of inflammation highlighting the macrophage and its proinflammatory cytokines. In particular, tumor necrosis factor alpha (TNF-alpha) has gained prominence as a central proinflammatory mediator in RA, and antibodies against TNF-alpha have been successfully used in patients with RA. 3. This review will summarize the recent advances in determining the mechanisms of action of the currently used DMARDs, with particular emphasis on their effects on the induction of TNF-alpha and interleukin 1 (IL-1) in mononuclear phagocytes. Although some DMARDs, such as auranofin, antimalarials and tenidap, act as inhibitors of the induction of these cytokines in monocytes or macrophages or both, other drugs, such as methotrexate, D-penicillamine and aurothiomalate, do not seem to affect either TNF-alpha or IL-1. 4. The drugs' effects on proinflammatory cytokine induction are correlated to those on other macrophage responses.

Auranofin and its combination with LTB4 influences ATP level and migration of human polymorphonuclear cells in vitro

Auranofin (AF), an orally administered antirheumatic drug, reduces the ATP level of PMN cells in vitro in a dose-dependent manner and provokes various effects on PMN migration. Under the experimental conditions, AF in concentrations between 10(-8) M and 10(-3) M produced a statistically significant (P < 0.05) dose-related reduction in ATP level, which ranged from 89% of the control value with 10(-8) M AF to 46.8% of the control with 10(-3) M AF. On the other hand, the combination of AF and the chemoattractant LTB4 (1 ng/ml) shows agonistic effects on the intracellular ATP level. AF at 10(-5) M significantly increases the ATP (33%; P < 0.03). In general migration of PMN cells is stimulated by 10(-7) M AF [chemotactic index (CI) = 1.26], but inhibited by 10(-5) M (CI = 0.65), 10(-4) M (CI = 0.09) and 10(-3) M AF (CI = 0.01). These effects were statistically significant at P < 0.05. In the presence of LTB4 (1 ng/ml), which resulted in an average CI of 2.9, AF also inhibits the chemotactic effect of the chemoattractant, with the CI being significantly reduced at 10(-6) M AF (CI = 2.3) and 10(-4) M AF (CI = 0.05). In the latter case the effect was also confirmed by the leading-front technique. AF at 10(-6) M is a level that could be reached in the blood after continuous therapy regimens, and these results are therefore of practical interest. They expand our knowledge of the effects of AF on PMN cells, whereby reducing effects on intracellular ATP were observed with AF alone and stimulating effects in combination with LTB4. With low AF concentrations, the reduction of the ATP level is only a part of its action that seems to be independent of its effect on cell migration and chemotaxis.

Effect of auranofin on cytokine induced secretion of granule proteins from adherent human neutrophils in vitro

The effect of auranofin on granule protein secretion from neutrophils was investigated by a haemolytic plaque assay which can detect release of lactoferrin and myeloperoxidase from single adherent neutrophils. Lactoferrin secretion in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP) was enhanced at low (0.25-1.0 micrograms/ml) and inhibited at high concentrations of auranofin (50% inhibition (IC50) at 3.7 micrograms/ml). A similar biphasic effect was also seen on degranulation mediated by granulocyte-macrophage colony stimulating factor (GM-CSF) (IC50 1.8 micrograms/ml). In contrast, exocytosis mediated by tumour necrosis factor was inhibited even at low concentrations of auranofin (IC50 0.6 micrograms/ml). Secretion induced by phorbol 12-myristate 13-acetate and A23187 was only inhibited at very high auranofin concentrations (IC50 10 and 8 micrograms/ml respectively). The effect of auranofin on myeloperoxidase secretion was also assessed and the IC50 values for the respective agents were as follows: tumour necrosis factor 0.7 micrograms/ml, fMLP 1.6 micrograms/ml, and phorbol myristate acetate 7.6 micrograms/ml. When neutrophils were preincubated with auranofin (4 micrograms/ml) and then exposed to fMLP, tumour necrosis factor, or GM-CSF in the absence of auranofin, lactoferrin release was enhanced if the preincubation time was short (one to three minutes) and inhibited when the time of preincubation was longer. It was concluded that auranofin, at concentrations achieved in the serum of patients, is a potent inhibitor of cytokine induced release of granule proteins from adherent neutrophils. This finding may be of clinical importance and shed light on the mechanism by which auranofin acts in rheumatoid arthritis.

Auranofin stimulates LTA hydrolase and inhibits 5-lipoxygenase/LTA synthase activity of isolated human neutrophils

The effect of auranofin on the 5-lipoxygenase pathway was studied in human neutrophils stimulated with either fMLP or A23187 (with or without arachidonic acid). The synthesis of leukotriene B4 (LTB4), 5-HETE and the all-trans isomers of LTB4 was measured by HPLC. At low concentrations (0.5-2.0 microM), auranofin stimulated LTB4 synthesis, but inhibited it at higher concentrations (100% inhibition at less than 10 microM). In contrast auranofin caused dose-dependent inhibition of the synthesis of 5-HETE and the all-trans isomers of LTB4. Similar observations were made with each agonist. The stimulation of LTB4 synthesis and inhibition of the trans isomer production suggests that auranofin at low concentrations stimulates LTA hydrolase--the enzyme that converts LTA4 to LTB4, whereas the inhibition of synthesis of all lipoxygenase products at higher auranofin concentrations, suggests inhibition of 5-lipoxygenase/LTA synthase.