Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1998-09-28
2002-08-27
Raymond, Richard L. (Department: 1624)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C514S063000, C514S081000, C514S185000, C540S452000, C540S460000
Reexamination Certificate
active
06441020
ABSTRACT:
GOVERNMENT FUNDING
A portion of this invention was made with U.S. government support under grant number 1R43GM42285 from the National Institutes of Health (NIGMS). The government may have certain rights in this invention.
BACKGROUND
Protein kinase C (also known as “calcium/phospholipid-dependent protein kinase”, “PKC” or “C-kinase) is a family of very closely related enzymes; one or more members of the protein kinase C family are found in nearly all animal tissues and animal cells that have been examined. The identity of protein kinase C is generally established by its ability to phosphorylate certain proteins when adenosine triphosphate and phospholipid cofactors are present, with greatly reduced activity when these cofactors are absent. Protein kinase C is believed to phosphorylate only serine and/or threonine residues in the proteins that are substrates for protein kinase C. Additionally, some forms of protein kinase C require the presence of calcium ions for maximal activity.
Protein kinase C activity is also substantially stimulated by certain 1,2-sn-diacylglycerols that bind specifically and stoichiometrically to a recognition site or sites on the enzyme. This site is called the diacylglycerol binding site, and it is located on the amino-terminal portion of protein kinase C, the so-called “regulatory domain”. The carboxy-terminal portion of protein kinase C carries the site at which protein phosphorylation is effected, and this portion is thus called the “kinase domain”.
Thus, the rate at which various protein kinase C family members carry out their enzymatic phosphorylation of certain substrates can be markedly enhanced by the presence of the cofactors such as phospholipids, diacylglycerols and, for some protein kinase C family members, calcium ions. This stimulation of protein kinase C activity is referred to as protein kinase C “activation”, and the activation of protein kinase C by the binding of diacylglycerols to the regulatory domain of protein kinase C is of particular importance in the normal and pathological functions of protein kinase C.
In contrast to the activation of protein kinase C, some chemical compounds have been shown, when added to protein kinase C enzyme assays, to reduce the rate at which protein kinase C phosphorylates its substrates; such compounds are referred to as protein kinase C “inhibitors” or, in some cases, “antagonists”. In some circumstances, protein kinase C inhibitors are capable of inhibiting various cellular or tissue phenomena which are thought to be mediated by protein kinase C.
Activation of protein kinase C by diacylglycerols has been shown to be an important physiological event that mediates the actions of a wide variety of hormones, neurotransmitters, and other biological control factors such as histamine, vasopressin, &agr;-adrenergic agonists, dopamine agonists, muscarinic cholinergic agonists, platelet activating factor, etc. {see Y. Nishizuka,
Nature
308: 693-698 (1984) and
Science
225: 1365-1370 (1984) for reviews}.
The biological role of protein kinase C is also of great interest because of the discovery that certain very powerful tumor promoting chemicals activate this enzyme by binding specifically and with very high affinity to the diacylglycerol binding site on the enzyme. In addition to diacylglycerols, there are at present six other known classes of compounds that bind to this site: diterpenes such as the phorbol esters; indole alkaloids (indolactams) such as the teleocidins, lyngbyatoxin, and indolactam V; polyacetates such as the aplysiatoxins and oscillatoxins; certain derivatives of diaminobenzyl alcohol; macrocyclic lactones of the bryostatin class; and benzolactams such as (−)-BL-V8-310. The phorbol esters have long been known as powerful tumor promoters, the teleocidins and aplysiatoxins are now known to have this activity, and it appears likely that additional classes of compounds will be found to have the toxic and tumor promoting activities associated with the capability to bind to the diacylglycerol site of protein kinase C and thus activate the enzyme. Other toxicities of these agents when administered to animals include lung injury and profound changes in blood elements, such as leukopenia and neutropenia.
Representative examples of these seven classes of previously known protein kinase C-activating compounds, collectively referred to herein as “phorboids”, are depicted below:
It can be seen that the seven basic classes of phorboids depicted have, from one class to another, diverse structural elements of both hydrophilic and hydrophobic nature, with one prominent exception, namely that each contains a hydroxymethyl or 1-hydroxyethyl group (indicated by the dashed-line boxes in each structure). In each case the phorboid depicted is among the most potent of its particular structural class, and among the seven classes the diterpenes, indolactams, polyacetates, bryostatins and benzolactams have members of especially high potency.
In addition to potent tumor promoting activity, these seven classes of compounds display a vast range of biological activities, as would be expected from the widespread distribution of their target enzyme. Some of these activities, like tumor promotion, indicate the involvement of protein kinase C in important normal or pathological processes in animals. Thus, the phorboids are potent skin inflammatory agents, cause smooth muscle contraction in several tissues, alter immune system function and can be used to cause a variety of other normal or pathological responses. Related disease states such as the development of cancer, the onset and/or maintenance of inflammatory disease, the role of vasoconstriction in hypertension, the role of bronchoconstriction in asthma, the life cycles of many pathogenic human viruses, and the role of cholinergic, adrenergic, and dopaminergic synapses in diseases of the central/peripheral nervous systems, may be mediated in vivo by the stimulation of protein kinase C or other diacylglycerol binding site-bearing entities by diacylglycerols, the latter being generated in the cell by pathological agents or conditions.
In analyzing the activity of a pharmaceutical or other bioactive compound, it is useful to consider two properties: the efficacy, defined as the capability to elicit a full or partial biological result, such as complete displacement of a ligand from its receptor site or the complete inhibition of inflammation or edema caused by a standard stimulus; and the potency, defined as that amount or concentration of drug that causes 50% of the full response (often abbreviated as the ED
50
). It is frequently the case within a given class of pharmaceutical agents that individual members of the class all have equal efficacy, i.e. they each can generate a full biological effect, but they show differing potencies. Thus, the structural modifications within such a class affect only the amount necessary to achieve a given result, and the modified compounds otherwise have generally the same central biological characteristic. There may also be differences between members of such a class as regards properties other than the central biological characteristic; for example, members of the class might differ in side effects or toxicity.
Well-known pharmaceuticals that have been in extensive use for years or decades show a wide range of optimal therapeutic potencies. Aspirin, for example, is often taken in multi-gram amounts per day for treatment of inflammation or arthritis, and detailed analyses of its mechanism of action in vitro show that a concentration in the millimolar range is required. In contrast, steroid-based, topical anti-inflammatory compounds, such as fluocinolone acetonide, are many thousand-fold more potent, and, beyond this, some oral contraceptive agents are prescribed in daily doses in the microgram range. Thus, although high potency is generally advantageous for a pharmaceutical, it is not an absolute requirement.
A thousand or more analogs of the highly skin-inflammatory and tumor-promoting phorboids have been reported in t
Driedger Paul E.
Quick James
Hamilton Brook Smith & Reynolds P.C.
Procyon Pharmaceuticals, Inc.
Raymond Richard L.
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