Antiglaucoma drug GLC756 and its effect on cellular cAMP and tumor necrosis factor α release in vitro of activated human monocytic leukemia cells

Purpose GLC756, a putative antiglaucoma drug with dopamine D 2 agonist and D 1 antagonist properties, significantly decreases tumor necrosis factor α (TNF-α) levels in lipopolysaccharide (LPS)-induced rats. The present study describes the effects of GLC756 on cellular adenosine 3′, 5′-cyclic monophosphate (cAMP) in relation to TNF-α production on LPS-stimulated human acute monocytic leukemia cells. Methods A human peripheral blood acute monocytic leukemia cell line (THP-1) was activated via LPS. THP-1 cells were incubated with GLC756 or betamethasone (positive control) at concentrations of 1, 10, and 30 μM. The TNF-α concentration in supernatant and cAMP levels in cellular extract were measured by enzyme-linked immunosorbent assay 0,1, 2.5, 4.5, 7, and 24 h post-activation. Results Compared with LPS controls, both GLC756 at 30 μM and betamethasone at ≥1 μM had a significant inhibitory effect on TNF-α release from THP-1 cells 2.5 to 24 h post-activation. Parallel to the TNF-α decrease, GLC756 induced significant increases of cellular cAMP 2.5 and 7 h post-activation. Betamethasone had no effect on the cellular cAMP level. Conclusion Intracellular signaling pathway leading to inhibition of the production of the proinflammatory cytokine TNF-α after GLC756 treatment might be mediated through the second messenger cAMP.