Drug – bio-affecting and body treating compositions – Immunoglobulin – antiserum – antibody – or antibody fragment,... – Binds antigen or epitope whose amino acid sequence is...
Reexamination Certificate
1998-09-10
2001-06-19
Caputa, Anthony C. (Department: 1642)
Drug, bio-affecting and body treating compositions
Immunoglobulin, antiserum, antibody, or antibody fragment,...
Binds antigen or epitope whose amino acid sequence is...
C424S130100, C530S387900, C530S388700, C530S388600
Reexamination Certificate
active
06248326
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the fields of biochemical endocrinology and regulation of bone formation and degradation. More specifically, the present invention relates to regulation of osteoclast formation by inhibition of osteoblastic stem cell factor.
2. Description of the Related Art
The human skeleton is continuously remodeled, normally turning over in ~2 years and allows use of skeletal mineral in calcium homeostasis. The strength and shape of the skeleton is preserved by segmental replacement: a bone section is degraded by osteoclasts, formed from monocyte-macrophage precursors,
1-2
while osteoblasts, derived from stromal cells,
3
synthesize new bone. These unrelated cells differentiate in a coupled manner, producing a new bone section in a few weeks.
Overall bone turnover responds to parathyroid hormone, but how differentiation of osteoblasts and osteoclasts is coordinated locally to maintain bone integrity is poorly understood. Osteoclast differentiation requires that precursors contact osteoblast-like cells,
4
suggesting specialized recognition molecules. In situ unlabeled antibody and Western blot analysis revealed that osteoblasts express a surface-bound form of stem cell factor (SCF; c-kit ligand) during bone synthesis only. Stem cell factor production in isolated osteoblasts responds to parathyroid hormone. Differentiation of osteoclasts from monocytes is supported by osteoblast-derived stem cell factor-producing cells in vitro, a process interrupted by antibody or antisense oligonucleotide targeting stem cell factor, indicating that it is a key element controlling this process.
The SCF/kit signaling pathway is very complex. Briefly summarized, stem cell factor binding induces receptor dimerization, which is associated with phosphorylation. Activity is transduced through intracellular kinases of the src family, the oncogene c-Cbl and pI-3 kinase. Src and Cbl are required for osteoclast differentiation; src, Cbl and PI-3-kinase interact with other osteoclast signaling molecules.
When ionized calcium is suppressed, such as with retention of phosphate in kidney failure, parathyroid hormone is secreted in large quantities and bone turnover increases as much as ten-fold, coupling of bone formation and degradation is maintained. Occurrence of stem cell factor in bone of hyperparathyroid subjects was examined because abnormal mast cell differentiation occurs around bone trabeculae of these patients,
5
and this protein causes mast cell differentiation in vitro.
6
Stem cell factor is expressed in a variety of forms in several tissues,
7
with a soluble form produced by a six-exon transcript and a longer membrane-associated form produced by an eight-exon transcript.
8
Additional variation occurs with proteolytic cleavage and glycosylation.
The prior art is deficient in the lack of effective means of inhibiting osteoclast formation and activity and thereby regulating bone formation and/or degradation. The present invention fulfills this longstanding need and desire in the art.
SUMMARY OF THE INVENTION
The present invention discloses, inter alia, that an antibody to a conserved region of the C-terminus of the c-kit ligand completely blocks the formation of human osteoclasts. This region is present in membrane-bound and some secreted forms of the protein, but is absent from other reported forms of the protein and may not required for some functions of c-kit ligand. Furthermore, in a controlled in vitro system with only osteoblast-like stromal cells and monocytes, osteoclast formation is blocked by antisense nucleotides or antibodies to stem cell factor and thus is a unique limiting factor coupling bone cell differentiation.
Osteoclasts mediate bone degradation that is responsible for osteoporosis, bone lesions in metastatic cancer, and other disease states. Thus, an application of the present invention is to control osteoclast formation, and therefore bone loss, in disease states of bone loss.
Using a c-kit ligand to reduce bone degradation has the particular advantage of inhibiting a system that affects, in (receptor) deficient mi/mi mice, only mast cells, and therefore has limited or no toxicity. Further, use of C-terminal blocking to inhibit osteoclast activity uses a portion of the molecule with no other known function.
Thus, use of antibodies or antisense nucleotides specific for the c-kit ligand, can reduce or prevent bone loss in aging (osteoporosis) or cancer progression (metastatic bone disease). These compounds target both the formation (tartrate-resistant acid phosphatase-positive cells) and the activity (bone resorption) of osteoclasts.
In one embodiment of the present invention, there is provided an inhibitor of osteoblastic SCF binding and/or activity.
In another embodiment of the present invention, there is provided a pharmaceutical composition, comprising an inhibitor of osteoblastic stem cell factor binding and/or activity and a pharmaceutically acceptable carrier.
In yet another embodiment of the present invention, there is provided a method of regulating the activity of osteoclasts, comprising the step of: inhibiting the binding and/or activity of osteoblastic stem cell factor.
In still yet another embodiment of the present invention, there is provided a method of treating a pathophysiological state in an animal in need of such treatment, wherein the pathophysiological state involves bone loss, comprising the steps of: administering a pharmaceutical composition disclosed herein to the animal.
In another embodiment of the present invention, there is provided a method of diagnosing bone disorders, comprising the step of measuring the activity of osteoblastic stem cell factor.
Other and further aspects, features, and advantages of the present invention will be apparent from the following description of the presently preferred embodiments of the invention given for the purpose of disclosure.
REFERENCES:
patent: 5911988 (1999-06-01), Brownell et al.
patent: 91/05795 (1991-05-01), None
Chatterjee et al, Idiotypic antibody immunotherapy of cancer, Cancer Immuno. Immunother. 38: 75-82. Jan. 1994.*
Osband et al, Problems in the investigational study and clinical use of cancer immuotherapy, Immunology Today 11(6): 193-195. Jun. 1990.*
Lemoli et al, Expression and functional role of c-kit ligand (SCF) in human multiple myeloma cells, Br. J. Haematology 88(4): 760-769. Apr. 13, 1994.*
Heidari et al, Characterization of the Growth Factor Activity of Amniotic Fluid on Cells from Hematopoietic and Lymphoid Organs of Different Life Stages, Microbiol. Immunol. 40(8):583-589. Aug. 23, 1996.*
Harlow et al, Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, pp. 71-82. Dec. 1988.*
Dunham et al DNA Sequence vol. 6 233-237, 1996.*
Efferth et al Med Oncol Tumor Pharmacology vol. 9(1) 11-19, 1992.*
Blair et al J Bone Mineral Res vol. 12 Suppl 1 T380 p. S196, Aug. 1997.*
Seaver Genetic Engineering vol. 14 No. 14 pp. 10 and 21 Aug. 1994.*
Battei et al J Cellular Biochem Suppl vol. 0 No. 18 Part A p. 23 Abstract 300, 1994.*
a. Eric J. Huang, et al.Differential Expression and Processing of Two Cell Associated Forms of the Kit-Ligand: KL-1 and KL-2, Molecular Biology of the Cell, vol. 3, pp. 349-362 (Mar. 1992).
b. Manas K. Majumdar, et al.Identification and Mutation of Primary and Secondary Proteolytic Cleavage Sites in Murine Stem Cell Factor cDNA Yields Biologically Active, Cell-associated Protein, The Journal of Biological Chemistry, vol. 269, No. 2, pp. 1237-1242 (Jan. 14, 1994).
c. Wayne E. Taylor, et al.Human Stem Cell Factor Promoter Deoxyribonucleic Acid Sequence and Regulation by Cyclic 3′, 5′-Adenosine Monophosphate in a Sertoli Cell Line, Endocrinology, vol. 137, No. 12, pp. 5407-5414 (1996).
d. Krisztina M. Zsebo, et al.Stem Cell Factor Is Encoded at the SI Locus of the Mouse and Is the Ligand for the c-kit Tyrosine Kinase Receptor, Cell, vol. 63, pp. 213-224 (Oct. 5, 1990).
e. Dirk M. Anderson, et al.Molecular Cloning of Mast Cell Growth Factor, a Hematopoietin that Is Acti
Blair Harry C.
Dong Sai-Sai
Julian Bruce A.
Adler Benjamin Aaron
Caputa Anthony C.
Holleran Anne L.
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