Inhibitors of human phosphatidylinositol 3-kinase delta

Details Inhibitors of human phosphatidylinositol 3-kinase delta Inhibitors of human phosphatidylinositol 3-kinase delta

2001-10-19

2003-12-23

Raymond, Richard L. (Department: 1624)

Drug, bio-affecting and body treating compositions

Designated organic active ingredient containing

Heterocyclic carbon compounds containing a hetero ring...

C514S266100, C514S266200, C514S266230, C514S266300, C544S283000, C544S287000, C544S290000

Reexamination Certificate

active

06667300

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to phosphatidylinositol 3-kinase (PI3K) enzymes, and more particularly to selective inhibitors of PI3K activity and to methods of using such materials.
BACKGROUND OF THE INVENTION
Cell signaling via 3′-phosphorylated phosphoinositides has been implicated in a variety of cellular processes, e.g., malignant transformation, growth factor signaling, inflammation, and immunity (see Rameh et al.,
J. Biol Chem,
274:8347-8350 (1999) for a review). The enzyme responsible for generating these phosphorylated signaling products, phosphatidylinositol 3-kinase (PI 3-kinase; PI3K), was originally identified as an activity associated with viral oncoproteins and growth factor receptor tyrosine kinases that phosphorylates phosphatidylinositol (PI) and its phosphorylated derivatives at the 3′-hydroxyl of the inositol ring (Panayotou et al.,
Trends Cell Biol
2:358-60 (1992)).
The levels of phosphatidylinositol-3,4,5-triphosphate (PIP3), the primary product of PI 3-kinase activation, increase upon treatment of cells with a variety of agonists. PI 3-kinase activation, therefore, is believed to be involved in a range of cellular responses including cell growth, differentiation, and apoptosis (Parker et al.,
Current Biology,
5:577-99 (1995); Yao et al.,
Science,
267:2003-05 (1995)). Though the downstream targets of phosphorylated lipids generated following PI 3-kinase activation have not been well characterized, emerging evidence suggests that pleckstrin-homology domain- and FYVE-finger domain-containing proteins are activated when binding to various phosphatidylinositol lipids (Sternmark et al.,
J Cell Sci,
112:4175-83 (1999); Lemmon et al.,
Trends Cell Biol,
7:237-42 (1997)). In vitro, some isoforms of protein kinase C (PKC) are directly activated by PIP3, and the PKC-related protein kinase, PKB, has been shown to be activated by PI 3-kinase (Burgering et al.,
Nature,
376:599-602 (1995)).
Presently, the PI 3-kinase enzyme family has been divided into three classes based on their substrate specificities. Class I PI3Ks can phosphorylate phosphatidylinositol (PI), phosphatidylinositol-4-phosphate, and phosphatidylinositol-4,5-biphosphate (PIP2) to produce phosphatidylinositol-3-phosphate (PIP), phosphatidylinositol-3,4-biphosphate, and phosphatidylinositol-3,4,5-triphosphate, respectively. Class II PI3Ks phosphorylate PI and phosphatidylinositol-4-phosphate, whereas Class III PI3Ks can only phosphorylate PI.
The initial purification and molecular cloning of PI 3-kinase revealed that it was a heterodimer consisting of p85 and p110 subunits (Otsu et al.,
Cell,
65:91-104 (1991); Hiles et al.,
Cell,
70:419-29 (1992)). Since then, four distinct Class I PI3Ks have been identified, designated PI3K &agr;, &bgr;, &dgr;, and &ggr;, each consisting of a distinct 110 kDa catalytic subunit and a regulatory subunit. More specifically, three of the catalytic subunits, i.e., p110&agr;, p110&bgr; and p110&dgr;, each interact with the same regulatory subunit, p85; whereas p110&ggr; interacts with a distinct regulatory subunit, p101. As described below, the patterns of expression of each of these PI3Ks in human cells and tissues are also distinct. Though a wealth of information has been accumulated in recent past on the cellular functions of PI 3-kinases in general, the roles played by the individual isoforms are largely unknown.
Cloning of bovine p110&agr; has been described. This protein was identified as related to the
Saccharomyces cerevisiae
protein: Vps34p, a protein involved in vacuolar protein processing. The recombinant p110&agr;product was also shown to associate with p85&agr;, to yield a PI3K activity in transfected COS-1 cells. See Hiles et al.,
Cell,
70, 419-29 (1992).
The cloning of a second human p110 isoform, designated p110&bgr;, is described in Hu et al.,
Mol Cell Biol,
13:7677-88 (1993). This isoform is said to associate with p85 in cells, and to be ubiquitously expressed, as p110&bgr; mRNA has been found in numerous human and mouse tissues as well as in human umbilical vein endothelial cells, Jurkat human leukemic T cells, 293 human embryonic kidney cells, mouse 3T3 fibroblasts, HeLa cells, and NBT2 rat bladder carcinoma cells. Such wide expression suggests that this isoform is broadly important in signaling pathways.
Identification of the p110&dgr; isoform of PI 3-kinase is described in Chantry et al.,
J Biol Chem,
272:19236-41 (1997). It was observed that the human p110&dgr; isoform is expressed in a tissue-restricted fashion. It is expressed at high levels in lymphocytes and lymphoid tissues, suggesting that the protein might play a role in PI 3-kinase-mediated signaling in the immune system. Details concerning the P110&dgr; isoform also can be found in U.S. Pat. Nos. 5,858,753; 5,822,910; and 5,985,589. See also, Vanhaesebroeck et al.,
Proc Natl Acad Sci USA,
94:4330-5 (1997), and international publication WO 97/46688.
In each of the PI3K&agr;, &bgr;, and &dgr; subtypes, the p85 subunit acts to localize PI 3-kinase to the plasma membrane by the interaction of its SH2 domain with phosphorylated tyrosine residues (present in an appropriate sequence context) in target proteins (Rameh et al.,
Cell,
83:821-30 (1995)). Two isoforms of p85 have been identified, p85&agr;, which is ubiquitously expressed, and p85&bgr;, which is primarily found in the brain and lymphoid tissues (Volinia et al.,
Oncogene,
7:789-93 (1992)). Association of the p85 subunit to the PI 3-kinase p110&agr;, &bgr;, or &dgr; catalytic subunits appears to be required for the catalytic activity and stability of these enzymes. In addition, the binding of Ras proteins also upregulates PI 3-kinase activity.
The cloning of p110&ggr; revealed still further complexity within the PI3K family of enzymes (Stoyanov et al.,
Science,
269:690-93 (1995)). The p110&ggr; isoform is closely related to p110&agr; and p110&bgr; (45-48% identity in the catalytic domain), but as noted does not make use of p85 as a targeting sub-unit. Instead, p110&ggr; contains an additional domain termed a “pleckstrin homology domain” near its amino terminus. This domain allows interaction of p110&ggr; with the &bgr;&ggr; subunits of heterotrimeric G proteins and this interaction appears to regulate its activity.
The p101 regulatory subunit for PI3Kgamma was originally cloned in swine, and the human ortholog identified subsequently (Krugmann et al.,
J Biol Chem,
274:17152-8 (1999)). Interaction between the N-terminal region of p101 with the N-terminal region of p110&ggr; appears to be critical for the PI3K&ggr; activation through G&bgr;&ggr; mentioned above.
A constitutively active PI3K polypeptide is described in international publication WO 96/25488. This publication discloses preparation of a chimeric fusion protein in which a 102-residue fragment of p85 known as the inter-SH2 (iSH2) region is fused through a linker region to the N-terminus of murine p110. The p85 iSH2 domain apparently is able to activate PI3K activity in a manner comparable to intact p85 (Klippel et al.,
Mol Cell Biol,
14:2675-85 (1994)).
Thus, PI 3-kinases can be defined by their amino acid identity or by their activity. Additional members of this growing gene family include more distantly related lipid and protein kinases including Vps34 TOR1, and TOR2 of
Saccharomyces cerevisiae
(and their mammalian homologs such as FRAP and mTOR), the ataxia telangiectasia gene product (ATR) and the catalytic subunit of DNA-dependent protein kinase (DNA-PK). See generally, Hunter,
Cell,
83:1-4 (1995).
PI 3-kinase also appears to be involved in a number of aspects of leukocyte activation. A p85-associated PI 3-kinase activity has been shown to physically associate with the cytoplasmic domain of CD28, which is an important costimulatory molecule for the activation of T-cells in response to antigen (Pages et al.,
Nature,
369:327-29 (1994); Rudd,
Immunity,
4:527-34 (1996)). Activation of T cells through CD28 lowers the threshold for activation by antigen and increases the magnitude and duration of

Affiliated with

Also associated with

Rating

Inhibitors of human phosphatidylinositol 3-kinase delta does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Inhibitors of human phosphatidylinositol 3-kinase delta, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inhibitors of human phosphatidylinositol 3-kinase delta will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3167269