Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Ester doai
Reexamination Certificate
2000-11-17
2002-10-22
Spivack, Phyllis G. (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Ester doai
C514S540000
Reexamination Certificate
active
06469063
ABSTRACT:
TECHNICAL FIELD
The present invention relates to methods for the treatment of inflammation, inhibition of cyclooxygenase-2 gene transcription, and in vivo activities of caffeic acid derivatives.
BACKGROUND OF THE INVENTION
Unlike cyclooxygenase-1 (COX-1), an enzyme that has constitutive expression in many tissues, cyclooxygenase-2 (COX-2) is induced by inflammatory stimuli like cytokines [1], lipopolysaccharide [2, 3], and mitogens [4, 5]. Both enzymes convert arachidonic acid to prostaglandin E2 (PGE2) and show similar kinetics for converting arachidonic acid to prostaglandin G2 and prostaglandin H2[6], but each appears to have different selectivity for non-steroidal antiinflammatory agents. With the recent development of specific COX-2 inhibitors, investigators have been able to more precisely define the roles of COX-1 and COX-2 enzymes in biological systems.
Cytokine-mediated COX-2 gene activation in pancreatic &bgr;-cells inhibits glucose stimulated insulin secretion through the generation of PGE2. The role of COX-2 gene activation and PGE2 production in the context of cellular stress may be viewed from two perspectives. First, PGE2 production is an attempt by the pancreatic &bgr;-cells to preserve function during an immune inflammatory attack. By generating PGE2, the &bgr;-cell sets off a regulatory mechanism to limit glucose stimulated insulin secretion that in turn allows the &bgr;-cell to conserve ATP and utilize its energy stores to transcribe genes that confer protection against oxidative stress. In addition, PGE2 release from &bgr;-cells may bias the immune towards a Th2 profile. PGE2 stimulates Th2 cytokine production in human lymphocytes [15], inhibits LPS-induced IL-1&bgr; production in microglial cells [3], limits Th1 cytokine responses [16], and prevents generation of interferon-&ggr; by inhibiting human IL-12 production [17]. Alternatively, PGE2 acts as a proinflammatory agent by inducing leukocyte migration [18], endothelial adhesion [19], painful response [20], and antigen stimulated interferon-&ggr; production in Th1 lymphocytes [21]. These apparent conflicting actions of PGE2 may ultimately be related to the ambient concentration of PGE2 in the affected tissue. Low concentrations of PGE2 as seen during basal states may promote cell survival, while high concentrations of PGE2 may promote cell demise. In this context, it is interesting to note that both COX-1 and COX-2 have endogenous peroxidase activity that may also contribute to either a pro- or anti-inflammatory state [6].
Pancreatic islets, like other tissues, express low basal levels of COX-2 and its metabolic end product, PGE2. Cellular stress can increase COX-2 mRNA levels from 3 to 5-fold and PGE2 production by greater than 100-fold. Early studies demonstrated that PGE2 production could be stimulated with alpha-adrenergic agonists and that prostaglandin synthase inhibitors could reverse the alpha-adrenergic-mediated inhibition of glucose-stimulated insulin secretion in human subjects [22]. Further work revealed that PGE2 had no effect as an insulin secretagogue, but did inhibit glucose-stimulated insulin secretion in pancreatic &bgr;-cells [8, 9]. PGE2 mediates its inhibitory effect on glucose-stimulated insulin secretion through stimulation of a pertussis-toxin sensitive GTPase protein that has yet to be cloned, but is likely to reside in the insulin secretory granule [23].
These findings led to the hypothesis that PGE2 may mediate the inhibitory effect of interleukin-1&bgr; (IL-1&bgr;) on glucose-stimulated insulin secretion, since IL-1&bgr;, itself, increases PGE2 production. However, McDaniel and colleagues demonstrated that nitric oxide (NO), not PGE2, mediates the inhibitory effects of IL-L1&bgr; on glucose-stimulated insulin secretion in rat pancreatic islets [24]. In addition, Turk and colleagues showed that L-NMMA, an inhibitor of iNOS, abrogated the inhibitory effect of IL-1&bgr; on glucose stimulated insulin secretion and partially inhibited PGE2 production through a mechanism that is likely to be post-translational (i.e., NO increases arachidonic acid substrate availability by inhibiting the reacylation of arachidonic acid into membrane phospholipid [25]). Thus, NO led to higher intracellular levels of arachidonic acid that could be converted to 12-HETE by 12-LO, and theoretically, PGE2 by COX-2, since arachidonic acid is a substrate for both 12-LO and COX-2. These results support prior studies in human islets showing that indomethacin, a non-selective cyclooxygenase inhibitor, enhanced glucose stimulated insulin secretion [26]. By increasing ambient arachidonic acid levels in the &bgr;-cell, indomethacin enhanced glucose stimulated insulin secretion since arachidonic acid, itself, is a potent insulin secretagogue [27]. In addition, by blocking PGE2 production through the inactivation of COX-1 and COX-2, indomethacin prevented PGE2 mediated inhibition of glucose stimulated insulin secretion.
More recently, Robertson demonstrated that the selective COX-2 inhibitor NS-398 partially restored glucose-stimulated insulin secretion in HIT cells treated with IL-1&bgr; for 24 hours (Diabetes 1999; 48:Supp. 1 :A1017). The implication of this study is that PGE2 may participate in cytokine-mediated pancreatic &bgr;-cell dysfunction, although this hypothesis has yet to be formally proven.
The selective COX-2 inhibitors discovered to date work at the post-transcriptional level. Callejas, et al. (1999) [30], for example, reported that indomethicin and the COX-2 specific inhibitor NS398, while both suppressing the activity of COX-2, lead to an accumulation of the protein in primary cultures of fetal hepatocytes and in cultured peritoneal macrophages. The authors found that the increased COX-2 levels were not the result of increased mRNA production, postulating that the accumulation was due to post-translation effects, such as increased stabilization of the enzyme, or decrease in the synthesis of prostaglandins that favor COX-2 degradation, or both. Callejas, et al. at 1240. Chan, et al. (1999) [31] obtained similar results with the selective COX-2 inhibitor rofecoxib in human osteosarcoma cells and Chinese hamster ovary cells. Chan, et al. found their results to be consistent with a two-step time-dependant model of reversible enzyme inhibition involving the formation of a tightly bound 1:1 enzyme-inhibitor complex. Chan, et al. at 555, 557. Gierse, et al. (1999) [32] conducted an in vitro comparison of the selective COX-2 inhibitor celecoxib and several non-steroidal anti-inflammatory drugs (NSAIDs), and proposed at least four distinct mechanisms of COX-2 inhibition, all of them at the post-translational level: (i) competitive; (ii) tight binding, time-dependent; (iii) weak binding, mixed; and (iv) covalent binding. Gierse, et al. at 615. In a recent minireview of research on the mechanisms of COX-1 and COX-2 catalysis and inhibition, Marnett, et al. (1999) [33] acknowledged that the regulatory aspects of cyclooxygenase function where poorly-understood (for example, the reason for the existence of two distinct cyclooxygenase genes—COX-1 and COX-2—sometimes expressed in the same cell type, is not known). Marnett, et al. at 22906. The authors described the topic as “an extremely important and exciting area of investigation.” Id. Furthermore, Michaluart et al. [35] investigated the effect of caffeic acid phenethyl ester (CAPE) on COX-2 activity and expression. Using both in vitro and in vivo models they demonstrated that this caffeic acid derivative inhibited the enzyme activity of both COX-1 and COX-2 at low concentration (14-28 &mgr;M), while higher concentrations (35-70 &mgr;M) inhibited COX-2 gene transcription. In addition, they utilized the rat carrageenan air pouch model (a standard model for evaluating anti-inflammatory properties of various drugs) to
Bleich David
Chen Songyuan
Han Xiao
City of Hope
Rothwell Figg Ernst & Manbeck
Spivack Phyllis G.
LandOfFree
Inhibition of inflammation via inhibition of COX-2 gene... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Inhibition of inflammation via inhibition of COX-2 gene..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inhibition of inflammation via inhibition of COX-2 gene... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2931524