Screening a small molecule library to identify inhibitors of NF-κB inducing kinase and pro-labor genes in human placenta.

The non-canonical NF-κB signaling (RelB/p52) pathway drives pro-labor genes in the human placenta, including corticotropin-releasing hormone (CRH) and cyclooxygenase-2 (COX-2), making this a potential therapeutic target to delay onset of labor. Here we sought to identify small molecule compounds from a pre-existing chemical library of orally active drugs that can inhibit this NF-κB signaling, and in turn, human placental CRH and COX-2 production. We used a cell-based assay coupled with a dual-luciferase reporter system to perform an in vitro screening of a small molecule library of 1,120 compounds for inhibition of the non-canonical NF-κB pathway. Cell toxicity studies and drug efflux transport MRP1 assays were used to further characterize the lead compounds. We have found that 14 drugs have selective inhibitory activity against lymphotoxin beta complex-induced activation of RelB/p52 in HEK293T cells, several of which also inhibited expression of CRH and COX-2 in human term trophoblast. We identified sulfapyridine and propranolol with activity against CRH and COX-2 that deserve further study. These drugs could serve as the basis for development of orally active drugs to affect length of gestation, first in an animal model, and then in clinical trials to prevent preterm birth during human pregnancy.

Effect of methotrexate and sulphasalazine on UMR 106 rat osteosarcoma cells.

Methotrexate is commonly used in the treatment of rheumatoid arthritis. An osteopathy has been described in children treated with methotrexate for leukaemia, consisting of bone pain, osteoporosis and fractures. Animals given short-term high-dose and long-term low-dose methotrexate have both reduced bone formation and increased resorption on histomorphometry. As patients with rheumatic diseases have numerous risk factors for osteoporosis, possible additional risk from low-dose methotrexate is of relevance to the rheumatologist. To investigate further the mechanism of osteoporosis in animals and man, in vitro studies were carried out on an osteoblast cell line, using concentrations found in patients with rheumatic disease. UMR 106 rat osteoblast-like osteosarcoma cells were incubated with methotrexate, and also with sulphasalazine, an anti-rheumatic drug with no known effect on bone, for comparison. A dose-dependent toxic effect of methotrexate on the cell line was observed using concentrations found in patients with rheumatic disease. This was not observed with sulphasalazine. The reduced bone formation observed in animals and man may be due to a direct effect of methotrexate on the osteoblast.

5-Aminosalicylic acid abrogates T-cell proliferation by blocking interleukin-2 production in peripheral blood mononuclear cells.

The antiinflammatory agent sulfasalazine (SS) is prescribed to treat Crohn's disease, ulcerative colitis and rheumatoid arthritis. Activated T cells are present within diseased mucosal and synovial sites. We tested whether SS or its metabolites 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP) inhibited the T-cell activation products interleukin 2 (IL-2) and interleukin 2 receptor alpha-chain (IL-2R alpha). Experiments were performed in phytohemaglutinin- and phorbol ester-stimulated peripheral blood mononuclear cells. Radioactive thymidine and leucine incorporation assayed DNA and protein synthesis, respectively. Enzyme-linked immunosorbent assay and Northern blot analysis measured IL-2 and IL-2R alpha. Lactate dehydrogenase release determined cell viability, and intracellular free calcium was measured by an indole fluorescent indicator. SS and 5-ASA, but not SP, inhibited T-cell proliferation and protein synthesis in phytohemaglutinin- and phorbol ester-stimulated peripheral blood monomuclear cells. 5-ASA (625 microM) markedly reduced culture supernatant IL-2 protein levels by 92% and steady-state IL-2 messenger RNA levels 4.4-fold at 24 and 18 hr, respectively. The supplementation of IL-2 restored T-cell proliferation only in 5-ASA-treated cultures. SS, 5-ASA and SP did not alter intracellular calcium accumulation after mitogenic stimulation. SS and 5-ASA (625 microM) caused 71% and 37% cytotoxicity, respectively, in 72-hr cultures. 5-ASA inhibits T-cell proliferation in part by blocking IL-2 messenger RNA accumulation and protein production downstream of the rise in cytosolic calcium. Inhibition of IL-2 production is an additional mechanism of action for 5-ASA.

Studies on the effects of pharmacological agents on antigen-induced arthritis in BALB/c mice.

The model of antigen-induced monoarticular arthritis in BALB/c mice, originally described by Brackertz et al. (1), has been examined with regard to disease pathogenesis and the activities of established antirheumatic agents. The acute phase of the arthritis, up to 7 days after intra-articular (IA) challenge, was characterized by intense polymorphonuclear leukocyte infiltration into the challenged joint, synovial lining cell hypertrophy and hyperplasia, accumulation of mononuclear cells within the subsynovial tissue, and pannus formation. Erosions of articular cartilage and bone commenced 7-14 days after IA challenge and progressed with time. Chronic synovitis was still evident 56 days after IA challenge. Prednisolone at 1 and 5 mg/kg, when administered against an established arthritis (dosing days 14-42), suppressed the histopathological changes. A similar level of suppression was observed when prednisolone was administered from days 0-42, indicating that the drug had no additional effect on the development phase of the arthritis. The non-steroidal anti-inflammatory agents (NSAIAs) indomethacin, ibuprofen and flurbiprofen failed to suppress either the established or developing disease. Daily treatment with D-penicillamine, tiopronin or chloroquine on days 14-42 had no significant effect on the arthritis; treatment with either D-penicillamine or chloroquine on days 0-56 was also ineffective. When administered on days 14-42 or 0-42 neither gold thiomalate nor auranofin were able to suppress the erosive changes. Sulphasalazine (10-30 mg/kg) suppressed the arthritis whereas sulphapyridine was inactive. Azathioprine (20 mg/kg) suppressed the erosive changes when administered over days 14-42 or 0-42; this activity was associated with toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

An experiment to determine the active therapeutic moiety of sulphasalazine.

Sulphasalazine (S.A.S.P.) is of proven value in the treatment of ulcerative colitis, but its mode of action is unknown. When it is taken by mouth, nearly all the dose reaches the colon intact, where it is split by bacteria into sulphapyridine (S.P.) and 5-aminosalicylic acid (5-A.S.A.). An experiment was devised to determine whether the therapeutic property of S.A.S.P. is a function of the parent molecule or of these two principal metabolites. Retention enemas of S.A.S.P., S.P., and 5-A.S.A. were administered to volunteer patients with sigmoidoscopic evidence of active ulcerative colitis. The experiment was conducted as a blind controlled therapeutic trial, each patient having one of the test enemas daily for two weeks. Pronounced histological improvement was observed in approximately 30% of the patients receiving S.A.S.P. or 5-A.S.A., and in only 5% of those receiving S.P. It is concluded that the active therapeutic moiety of S.A.S.P. IS 5-A.S.A. and that the S.P. functions as a carrier ensuring that the 5-A.S.A. is liberated within the colon.