LL-Z1271alpha: an interleukin-1beta production inhibitor.

LL-Z1271alpha, a fungal metabolite, dose-dependently inhibited interleukin-1beta (IL-1beta) production in lipopolysaccharide (LPS)-stimulated human whole blood. Oral administration of LL-Z1271alpha to LPS-challenged mice caused significant lowering in the IL-1beta levels in peritoneal cavity. Data presented suggest that LL-Z1271alpha inhibits IL-1beta production by a novel mechanism as the inhibitory activity was not due to effects on caspase-1 (IL-1beta converting enzyme), the ATP-induced release mechanism or a lysosomotrophic effect.

Inhibition of cytokine activation processes in vitro by tenidap, a novel anti-inflammatory agent.

Tenidap is a novel anti-inflammatory and anti-arthritic agent that lowers intracellular pH and suppresses anion transport when applied to cells in vitro. Both of these parameters are known to influence pro-inflammatory cell function. To investigate whether tenidap can modulate cellular responses to cytokine stimulation, several in vitro cytokine-driven assays were characterized with respect to their tenidap sensitivity. Human monocytes treated with granulocyte-macrophage colony stimulating factor (GM-CSF) demonstrated an increased production of IL-6 as well as an increased total translational activity. Tenidap dose-dependently inhibited both cytokine-induced responses; the effect on IL-6, however, occurred at lower tenidap concentrations than those required to prevent the increase in total translational activity. In contrast, the known translational inhibitor cycloheximide did not demonstrate selectivity for IL-6; this agent decreased the GM-CSF-induced increase in total translational activity in parallel with its effects on IL-6. GM-CSF-treated monocytes also produced greater amounts of IL-1 beta in response to LPS stimulation than did non-GM-CSF-treated cells, and tenidap again suppressed this cytokine-induced activation. Human Hep3B cells treated with a combination of interleukin (IL)-1 beta and IL-6 demonstrated an acute phase-type of response. These hepatoma cells increased production of the positive acute phase protein serum amyloid A (SAA) while they decreased production of a negative acute phase protein human serum albumin (HSA). Tenidap dose-dependently inhibited the cytokine-induced increase in SAA production without effecting synthesis of HSA or total TCA-precipitable macromolecules. Importantly, the ability of tenidap to alter these various cytokine responses was not shared with piroxicam, a potent cyclooxygenase inhibitor. Finally, human neutrophils treated with either GM-CSF or tumor necrosis factor (TNF)-alpha demonstrated an increased chloride conductance as measured by the loss of radioactive chloride from 36Cl-loaded cells. When tenidap was included within the medium during cytokine stimulation, loss of radioactive chloride was prevented. Thus, tenidap inhibited the cytokine-induced increase in anion transport. Together, these results indicate that tenidap can suppress cellular activation processes induced by a variety of cytokines. This functional antagonism is not dependent on cyclooxygenase inhibition but, rather, appears to link to tenidap's unique ability to alter ionic homeostasis. These in vitro observations, therefore, may help to explain how this novel anti-inflammatory agent acts to lower acute phase proteins and IL-6 levels in man.

Synovial fluid from rheumatoid arthritis patients contains sufficient levels of IL-1 beta and IL-6 to promote production of serum amyloid A by Hep3B cells.

The presence of positive acute phase proteins within the circulation of rheumatoid arthritis patients suggests that elevated cytokine production associated with this chronic inflammatory disorder initiates the hepatic acute phase response. Cytokines produced at inflammatory lesions are believed to travel via the circulation to the liver where they induce acute phase protein production by hepatocytes. To test whether serum from rheumatoid arthritis patients contained sufficient levels of cytokines to promote an acute phase response in vitro, a bioassay was developed that employed the human hepatoma cell line Hep3B. These cells produced the acute phase protein serum amyloid A (SAA) in response to a combination of recombinant IL-1 beta and IL-6 or to monocyte conditioned medium. Serum (or plasma) from normal individuals or from rheumatoid arthritis patients did not induce SAA production by Hep3B cells. Moreover, these serum samples did not prevent SAA production induced by monocyte conditioned medium, indicating that they did not contain inhibitors of cytokine activity. Despite the inactivity of serum samples, synovial fluid samples obtained from rheumatoid arthritis patients were active in the hepatocyte bioassay and promoted SAA synthesis. One synovial fluid sample was analysed in detail to identify cytokines responsible for the SAA-inducing activity. Neutralizing antisera against IL-6 and IL-1 beta blocked this activity by > 90% whereas anti-IL1 alpha and anti-TNF-alpha sera were without effect. Absolute cytokine levels within the synovial fluid sample were determined by ELISA; IL-6, IL-beta and TNF-alpha, but not IL-1 alpha, were confirmed to be present. Moreover, the synovial fluid sample contained a large amount of the IL-1 receptor antagonist. These data indicate, therefore, that synovial fluid recovered from an inflamed joint contains all the necessary cytokines in balance with inhibitors to promote SAA production by Hep3B cells. The steady state levels of these factors within the plasma compartment, however, were insufficient to induce the acute phase response by cultured Hep3B cells, suggesting that this system does not mimic the relationship between the circulation and the liver that likely exists in rheumatoid arthritis patients.

Quantitative structure-activity relationships of antitumor guanidinothiazolecarboxamides with survival enhancement for therapy in the 3LL Lewis lung carcinoma model.

Guanidinothiazolecarboxamides (GTCs) are a novel class of antitumor agents found to be systemically active against experimental pulmonary metastases of 3LL Lewis lung carcinoma. A series of substituted benzothiazole GTCs were found to produce enhancement of survival in this model by using 8 days of intraperitoneal dosing initiated 2 days after intravenous tumor challenge. Quantitative structure-activity relationships have been discovered in the GTC series with survival enhancement correlated to substituent parameters. Optimal correlations were found between the probit transform of the drug-induced increased lifespan (ILS) and field and pi parameters. Among the most effective analogues in this series was N-(5-fluorobenzothiazol-2-yl)-2-guanidinothiazole-4-carboxam ide.