CS-706, a novel cyclooxygenase-2 selective inhibitor, prolonged the survival of tumor-bearing mice when treated alone or in combination with anti-tumor chemotherapeutic agents.

The potent chemopreventive activity of cyclooxygenase-2 (COX-2) inhibitors has been demonstrated in a number of preclinical studies, but their potency in antitumor activity is still in dispute. In this report, we demonstrate the potent antitumor activity of a novel COX-2 inhibitor, CS-706 in mouse colorectal adenocarcinoma colon 26 tumor-bearing mice treated with or without antitumor chemotherapeutic agents. Daily oral administration of CS-706 at doses of 3-100 mg/kg from the day of tumor inoculation (Day 0) inhibited tumor growth dose-dependently, and the maximal inhibition was 67% at a dose of 100 mg/kg. In contrast, celecoxib, a well-known COX-2 inhibitor, did not inhibit tumor growth at doses up to 100 mg/kg. Furthermore, CS-706 at a dose of 1 mg/kg or above markedly prolonged the survival time of tumor-bearing mice. Administration of 30 mg/kg CS-706 from Day 7 combined with a single intravenous treatment of 10 mg/kg cisplatin on Day 7 completely regressed the tumors in all tumor-bearing mice examined, whereas only in 1 of 10 mice tumor was regressed with cisplatin treatment. Similar combination effects were observed with 10 mg/kg CS-706 and 60 mg/kg 5-fluorouracil (5-FU). Moreover, 10 mg/kg CS-706 significantly inhibited angiogenesis induced by implanted chambers with colon 26 cells in a dorsal air sac assay in mice. Collectively, these results suggest that CS-706 is a potent antitumor agent, especially in combination with conventional chemotherapeutic agents, and that the anti-angiogenic activity of CS-706 may contribute at least in part to its marked antitumor activity.

Preclinical pharmacology profile of CS-706, a novel cyclooxygenase-2 selective inhibitor, with potent antinociceptive and anti-inflammatory effects.

We report here the preclinical anti-inflammatory profile of CS-706 [2-(4-ethoxyphenyl)-4-methyl-1-(4-sulfamoylphenyl)-1H-pyrrole], a novel cyclooxygenase-2 (COX-2) selective inhibitor. CS-706 selectively inhibited COX-2 in a human whole blood assay with an IC(50) of 0.31 microM, compared with an IC(50) of 2.2 microM for COX-1. The selectivity ratio of CS-706 was higher than those of the conventional non-steroidal anti-inflammatory drugs naproxen, indomethacin, and Diclofenac-Na, whereas it was lower than those of rofecoxib, valdecoxib and etoricoxib. It was similar to that of celecoxib. The pharmacokinetic profile of CS-706 showed rapid absorption and dose-proportional exposure after oral administration to rats. CS-706 inhibited prostaglandin E(2) production in inflamed tissue induced by yeast-injection in rats with potency similar to that of indomethacin. However, it inhibited gastric mucosal prostaglandin E(2) production in normal rats weakly compared with indomethacin. CS-706 ameliorated both yeast-induced inflammatory acute pain (ED(50)=0.0090 mg/kg) and adjuvant-induced chronic arthritic pain (ED(50)=0.30 mg/kg) in rats. CS-706 showed more potent antinociceptive activity than celecoxib and rofecoxib in these models. In an adjuvant-induced arthritic model in rats, CS-706 suppressed foot swelling prophylactically with an ID(50) of 0.10 mg/kg/day, and decreased foot swelling in the established arthritis therapeutically in a dose range of 0.040 to 1.0 mg/kg/day. Single administration of up to 100 mg/kg of CS-706 induced no significant gastric lesions in rats. In conclusion, CS-706 is a COX-2-selective inhibitor with a potent antinociceptive and anti-inflammatory activity and a gastric safety profile.

Novel p38 mitogen-activated protein kinase inhibitor R-130823 protects cartilage by down-regulating matrix metalloproteinase-1,-13 and prostaglandin E2 production in human chondrocytes.

In order to study the involvement of mitogen-activated protein kinase p38 in osteoarthritis, we investigated the effect of novel p38 inhibitor R-130823 {2-(4-fluorophenyl)-4-(1-phenethyl-1,2,3,6-tetrahydropyridin-4-yl)-3-(pyridin-4-yl)-1H-pyrrole} on human chondrocytes and bovine cartilage. In human primary chondrocytes, the production of matrix metalloproteinase-13 and -1 (MMP-13 and -1) and prostaglandin E2 (PGE2) was induced by interleukin-1beta. Pretreatment with R-130823 inhibited the release of MMP-13, MMP-1 and PGE2 with IC50 values of 20, 230 and 3.9 nM, respectively. The inhibitory activity was also confirmed by a decrease in MMP-13 release from human chondrosarcoma cell line SW1353 with an IC50 value of 17 nM. Ribonuclease protection assay on human primary chondrocytes indicated that MMP-13 and MMP-1 mRNA levels almost reached the maximum 14 h after IL-1 stimulation, while cyclooxygenase-2 (COX-2) mRNA quickly reached the maximum 4 h after the stimulation. R-130823 down-regulated the steady-state levels of MMP-13 and MMP-1 mRNA with IC50 values of 4.2 and 79 nM, respectively. The COX-2 mRNA level was also suppressed with an IC50 value of 21 nM. In the explant culture of bovine nasal cartilage, R-130823 suppressed the collagen cleavage induced by interleukin-1alpha and oncostatin M, but not IL-1beta-mediated glycosaminoglycan release. These results suggest that activated p38 accelerates cartilage breakdown by enhancing the expression of MMPs responsible for collagen cleavage, which thus implies chondroprotective effects of p38 inhibitors in osteoarthritis.

Novel p38 MAP kinase inhibitor R-130823 suppresses IL-6, IL-8 and MMP-13 production in spheroid culture of human synovial sarcoma cell line SW 982.

Synovial hyperplasia is a hallmark of rheumatoid arthritis (RA) and is regarded as a major destructive element of articular bone and cartilage. This pathological process is accompanied by the production of proinflammatory cytokines, prostaglandin E(2) (PGE(2)), and matrix metalloproteinases (MMPs) in synoviocytes. We studied the spontaneous production of these substances in RA synoviocytes in spheroid culture. Synovial sarcoma cell line SW 982 formed a single spheroid in non-adherent culture plates. It produced interleukin (IL)-1beta, IL-6, IL-8, PGE(2), MMP-2 and MMP-13. Neither the addition of integrin antagonizing oligopeptide (GRGDSP) nor that of vitronectin receptor inhibitor SB-265123 to the culture inhibited any production. Phosphorylation of p38 mitogen-activated protein (MAP) kinase was observed during the culture. A novel p38 MAP kinase inhibitor, R-130823, inhibited the release of IL-6, IL-8 and MMP-13 in a concentration-dependent manner, but not that of IL-1beta or MMP-2. Real-time RT-PCR analysis demonstrated that IL-6, IL-8 and MMP-13 were inhibited at the transcriptional level. R-130823 did not affect the production of PGE(2) in spheroid culture, while the addition of R-130823 suppressed IL-1beta-induced PGE(2) synthesis in monolayer culture of SW 982 cells. The results suggest that spheroid culture induced proinflammatory factors and MMPs in signaling pathways both dependent and independent of p38 MAP kinase.

R-130823, a novel inhibitor of p38 MAPK, ameliorates hyperalgesia and swelling in arthritis models.

We found that a novel compound, R-130823 {2-(4-fluorophenyl)-4-(1-phenethyl-1,2,3,6-tetrahydropyridin-4-yl)-3-(pyridin-4-yl)-1H-pyrrole}, had highly selective inhibition against mitogen-activated protein kinase p38alpha (IC50=22 nM). The release of tumor necrosis factor-alpha, interleukin-1beta, -6 and -8 was inhibited in lipopolysaccharide-stimulated human blood pretreated by R-130823, with IC50 values of 0.089, 0.066, 0.95 and 0.16 microM, respectively. R-130823 reduced the established hind paw swelling in rat adjuvant-induced arthritis, while methotrexate showed no suppression. In the same model, R-130823 ameliorated adjuvant-induced hyperalgesia with rapid onset and long duration comparable to a cyclooxygenase-2 inhibitor, celecoxib. In murine collagen-induced arthritis, R-130823 blocked the progress of arthritis when administered just after the onset of the arthritis. Histological analysis of the knee joints showed that proliferation of fibroblasts and synoviocytes and infiltration of neutrophils were ameliorated. In conclusion, R-130823 is expected to be an efficacious treatment for rheumatoid arthritis by blocking the p38 pathway.

Anti-HIV-1 activities and pharmacokinetics of new arylpiperazinyl fluoroquinolones.

Anti-HIV-1 activities and pharmacokinetics of a series of novel arylpiperazinyl fluoroquinolones are reported. Modification at the C-8 position with a trifluoromethyl group was superior to that with a difluoromethoxy group to achieve higher anti-HIV-1 activity. Two compounds studied exhibited quite high anti-HIV-1 activities (IC(50)<50 nM) in vitro and high bioavailabilities (BA>90%) in monkeys.