Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving nucleic acid
Reexamination Certificate
1999-09-16
2002-02-05
Wang, Andrew (Department: 1635)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving nucleic acid
C435S325000, C435S366000, C435S375000, C536S023100, C536S024500, C536S025300, C514S04400A
Reexamination Certificate
active
06344323
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the field of therapeutic compositions and more specifically to antisense oligonucleotides that bind to Cyclooxygenase-2 (COX-2) polynucleotides and methods of treatment for diseases associated with COX-2.
BACKGROUND OF THE INVENTION
Eicosanoids are described as paracrine hormones derived from C20 fatty acids and released from membrane lipids in response to cellular signals. Those compounds are divided into two groups: leukotrienes and prostanoids, both formed from arachidonic acid (AA) by two distinct enzymatic pathways. Prostaglandin synthase (cyclooxygenase, cox) is the main enzyme that catalyzes the first biosynthetic steps of prostanoids conversion from AA. First, the oxidation of AA to prostaglandin G2 and second, the reduction to prostaglandin H2, which is a common precursor for all prostaglandins (PGs), thromboxanes (TBs) and prostacyclines (PIs). The purification of prostaglandin synthase and characterization of its biological activity was first reported in the 1970's (1), however the first ovine cDNA sequence was cloned a decade later (2). This information was used to clone the human gene (3), which is 25 kilobases (kb) long and contains eleven exons separated by ten introns and produces 2.8 kb long mRNA (4). Until the beginning of this decade it was believed that only one cox gene existed. For many years it was assumed that prostaglandin generation in response to cellular stimulation was limited by AA availability or due to the constitutively expressed enzyme (cox-1) (5). However, the studies of glucocorticoid inhibition of cox activity, prostanoid synthesis and mitogen-induced prostaglandins production suggested the existence of another enzyme (6). The discovery of the second cox gene (cox-2) occurred after the examination of gene expression in chicken embryo cells transformed with RNA tumor viruses (7). The human gene was subsequently cloned (8) showing a substantially smaller gene size of approximately 8 kb (9), but similar to cox-1 exon-intron structure (10). The comparison of cox-1 and cox-2 protein structures reveals 64% overall amino acid identity between enzymes. However, the cox-1 protein contain a short sequence (17 amino acids) at amino terminus that is not present in the cox-2 protein (11) and cox-2 contains another sequence (18 amino acids) at carboxyl terminus that is not present in the cox-1 protein. In spite of structural similarities, there are differences between both enzymes in substrate and inhibitor selectivity, e.g., cox-2 accepts a wider range of fatty acids as substrates than cox-1 (4). Moreover, cox-2 is present on the nuclear membrane and the endoplasmic reticulum (ER), while cox-1 is found only on the ER membranes (12). Cox-1 protein and mRNA was detected in virtually all mammalian tissues (5) and cox-2 mRNA was detected in all examined tissues (14). The constitutive form of the enzyme is now termed cox-1 and the inducible form is called cox-2. The induction of cox-2 gene occurs in response to growth factors, oncogene expression, depolarization in neurons, in hormonal response in osteoblasts, mesangial and granulosa cells, and in inflammatory response in macrophages, neutrophils, epithelial and endothelial cells, synoviocytes, chondrocytes, mast and amnion cells (13, 18). However, cox-2 is constitutively expressed in neurons and gastric mucosa (14, 22). The cox-1 and cox-2 enzymes are respectively called physiological and pathological because most of the stimulatory processes that induce cox-2, are associated with inflammation like bacterial lipopolysaccharide, interleukin-1 and tumor necrosis factor alpha, while cox-1 expression is important in cytoprotection and maintaining physiological functions. The corticosteroids and anti-inflammatory interleukins decrease cox-2 activity (13,15). Most conventional nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cox activity by acetylation of Ser-530 located near the active site, preventing the entrance of substrate AA and its contact with the Tyr-385 active site (20, 21). Moreover, NSAIDs side-effects like gastrointestinal bleeding and renal dysfunction are considered to be caused by the inhibition of cox-1 physiological functions (23). The gene knockout experiments in mice show that cox-1 gene disruption caused platelets unresponsiveness to AA, no gastric or intestinal bleeding nor any renal pathology but reduction of fetus survival (28). The cox-2 knockout strain shows unchanged response to inflammation, but on the other hand infertility due to the lack of ovulation and massive renal developmental deficiencies (29, 30). Prostanoids play important role in human physiology, which is demonstrated by biological and pharmaceutical significance of cox inhibitors. They mediate a variety of intra- and extracellular interactions including homeostasis, bone development, glomerular filtration and water balance, bronchodilatory respiratory function, cryoprotective gastric function, ovulation, fertilization, embryo implantation and development, labor initiation, modulation of immunological responses, sleep and other processes in central nervous system. Prostaglandins show both vasodilatory and venule vasoconstrictory activities.
Cox-1 is the only form detectable in platelets responsible for AA-induced platelets aggregation. Inhibition of cox-1 leads to decreased production of thromboxane A2 in platelets and prostacyclin in endothelial cells. However, cox-1 activity regenerates in endothelial cells and prostacyclin production is reestablished. This effect provides grounds for prophylaxis against thromboembolic disease (16). The cytoprotective role of prostanoids in the stomach and intestine is mostly due to their vasodilating abilities causing increased mucosal blood flow and preserving the integrity of mucosal epithelium (19).
High level of Cox-2 is associated with active gastritis caused by bacterium
Helicobacter pylori
(39). It seem that cox-1 is predominant generator of protective gastric mucosal prostaglandins even with
Helicobacter pylori
infection raising the possibility of therapeutic selective cox-2 inhibition.
Epidemiological studies showed that chronic intake of NSAIDs decreases the incidence of colon and breast cancers and a 50% reduction in mortality in patients with colorectal cancer (41,42). Similar effect during treatment was observed in young patients with familiar adenomatous polyposis, a pathological condition in which colorectal polyps develop spontaneously and progress to tumors (43). Human breast tumors and colorectal adenomas and adenocarcinomas express higher levels of cox-2 gene and protein than surrounding normal tissues (44,45), providing an attractive therapeutic target.
Similar epidemiological studies showed the correlation between cox enzymes, prostaglandin production and Alzheimer's disease (AD), Parkinson's disease and other neurogenerative diseases. AD is a progressive dementing illness characterized by pathological features like neuritic amyloid plaques, neurofibrillary tangles, loss of neuronal cells and synapses and increased gliosis. Several studies disclosed 50% reduced risk for AD in individuals taking NSAIDs (46,47) and reduced severity and incidence of AD (48). Inflammatory events like increased expression of proinflammatory cytokines such as interleukin-1 and tumor necrosis factor alpha, intracellular adhesion molecule ICAM-1, complement cascade and acute phase protein alpha-1 antichymotrypsin all are present in AD (49, 50, 51, 52). Cox-2 but not cox-1 mRNA expression is elevated in cerebral cortex and hippocampal formation of AD brain and cox-2 protein content correlates with the amount of amyloid plaques (53). A major therapeutic benefit of the new selective cox-2 inhibitors can lead to delaying or preventing AD in subject genetically at risk. Inflammation contributes also to ischemic stroke and cox-2 increased expression is present after stroke in damage neurons causing accelerated apoptotic death. The reduced expression of cox-2 by drugs inhibiting microglial activation after stroke
Fish & Richardson P.C.
Schmidt Mary
Vitagenix, Inc.
Wang Andrew
LandOfFree
Compositions and methods for inhibiting cox-2 expression and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compositions and methods for inhibiting cox-2 expression and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compositions and methods for inhibiting cox-2 expression and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2979274