Chemistry: natural resins or derivatives; peptides or proteins; – Proteins – i.e. – more than 100 amino acid residues
Reexamination Certificate
1998-10-14
2002-06-04
Arthur, Lisa B. (Department: 1655)
Chemistry: natural resins or derivatives; peptides or proteins;
Proteins, i.e., more than 100 amino acid residues
Reexamination Certificate
active
06399746
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to polypeptide ligands that bind to receptors implicated in cellular growth. In particular, it relates to polypeptide ligands that bind to the p185
HER2
receptor.
2. Description of Background and Related Art
Cellular protooncogenes encode proteins that are thought to regulate normal cellular proliferation and differentiation. Alterations in their structure or amplification of their expression lead to abnormal cellular growth and have been associated with carcinogenesis (Bishop J M,
Science
235:305-311, 1987); (Rhims J S,
Cancer Detection and Prevention
11:139-149, 1988); (Nowell P C,
Cancer Res
46:2203-2207, 1986); (Nicolson G L,
Cancer Res
47:1473-1487, 1987). Protooncogenes were first identified by either of two approaches. First, molecular characterization of the genomes of transforming retroviruses showed that the genes responsible for the transforming ability of the virus in many cases were altered versions of genes found in the genomes of normal cells. The normal version is the protooncogene, which is altered by mutation to give rise to the oncogene. An example of such a gene pair is represented by the EGF receptor and the v-erB gene product. The virally encoded v-erB gene product has suffered truncation and other alterations that render it constitutively active and endow it with the ability to induce cellular transformation (Yarden Y, Ullrich A L,
Ann Rev Biochem
57:443-478, 1988).
The second method for detecting cellular transforming genes that behave in a dominant fashion involves transfection of cellular DNA from tumor cells of various species into nontransformed target cells of a heterologous species. Most often this was done by transfection of human, avian, or rat DNAs into the murine NIH 3T3 cell line (Bishop J M,
Science
235:305-311, 1987); (Rhims J S,
Cancer Detection and Prevention
11:139-149, 1988); (Nowell P C,
Cancer Res
46:2203-2207, 1986); (Nicolson G L,
Cancer Res
47:1473-1487, 1987); (Yarden Y, Ullrich A L,
Ann Rev Biochem
57:443-478, 1988). Following several cycles of genomic DNA isolation and retransfection, the human or other species DNA was molecularly cloned from the murine background and subsequently characterized. In some cases, the same genes were isolated following transfection and cloning as those identified by the direct characterization of transforming viruses. In other cases, novel oncogenes were identified. An example of a novel oncogene identified by this transfection assay is the neu oncogene. It was discovered by Weinberg and colleagues in a transfection experiment in which the initial DNA was derived from a carcinogen-induced rat neuroblastoma (Padhy L et al.,
Cell
28:865-871, 1982.); (Schechter A L et al.,
Nature
312:513-516, 1984.) Characterization of the rat neu oncogene revealed that it had the structure of a growth factor receptor tyrosine kinase, had homology to the EGF receptor, and differed from its normal counterpart, the neu protooncogene, by an activating mutation in its transmembrane domain (Bargmann C I, Hung M-C, Weinberg R A,
Cell
45:649-657, 1986). The human counterpart to neu is the HER2 protooncogene, also designated c-erbB2 (Coussens et al.,
Science
, 230:1137-1139, 1985); U.S. Ser. No. 07/143,912).
The association of the HER2 protooncogene with cancer was established by yet a third approach, that is, its association with human breast cancer. The HER2 protooncogene was first discovered in cDNA libraries by virtue of its homology with the EGF receptor, with which it shares structural similarities throughout (Yarden Y, Ullrich A L,
Ann Rev Biochem
57:443-478, 1988). When radioactive probes derived from the cDNA sequence encoding p185 HER2 were used to screen DNA samples from breast cancer patients, amplification of the HER2 protooncogene was observed in about 30% of the patient samples (Slamon D J, Clark G M, Wong S G, Levin W J, Ullrich A, McGuire W L,
Science
235:177-182, 1987). Further studies have confirmed this original observation and extended it to suggest an important correlation between HER2 protooncogene amplification and/or overexpression and worsened prognosis in ovarian cancer and non-small cell lung cancer (Slamon D J, et al.,
Science
244:707-712, 1989); (Wright C, et al.,
Cancer Res
49:2087-2090, 1989); (Paik S, et al.,
J Clin Oncology
8:103-112, 1990); (Berchuck A, et al.,
Cancer Res
. 50:4087-4091, 1990); (Kern J A, et al.,
Cancer Res
. 50:5184-5191, 1990).
The association of HER2 amplification/overexpression with aggressive malignancy, as described above, implies that it may have an important role in progression of human cancer; however, many tumor-related cell surface antigens have been described in the past, few of which appear to have a direct role in the genesis or progression of disease (Schlom J, et al.
Cancer Res
50:820-827, 1990); (Szala S, et al.,
Proc. Natl. Acad Sci
. 98:3542-3546).
Among the protooncogenes are those that encode cellular growth factors which act through endoplasmic kinase phosphorylation of cytoplasmic protein. The HER1 gene (or ERB-B1) encodes the epidermal growth factor (EGF) receptor. The &bgr;-chain of platelet-derived growth factor is encoded by the c-sis gene. The granulocyte-macrophage colony stimulating factor is encoded by the c-fms gene. The neu proto-oncogene has been identified in ethylnitrosourea-induced rat neuroblastomas.
The known receptor tyrosine kinases all have the same general structural motif: an extracellular domain that binds ligand, and an intracellular tyrosine kinase domain that is necessary for signal transduction and transformation. These two domains are connected by a single stretch of approximately 20 mostly hydrophobic amino acids, called the transmembrane spanning sequence. This transmembrane spanning sequence is thought to play a role in transferring the signal generated by ligand binding from the outside of the cell to the inside. Consistent with this general structure, the human p185
HER2
glycoprotein, which is located on the cell surface, may be divided into three principal portions: an extracellular domain, or ECD (also known as XCD); a transmembrane spanning sequence; and a cytoplasmic, intracellular tyrosine kinase domain. While it is presumed that the extracellular domain is a ligand receptor, the p185
HER2
ligand has not yet been positively identified. The HER2 gene encodes the 1,255 amino acid tyrosine kinase receptor-like glycoprotein p185
HER2
that has homology to the human epidermal growth factor receptor. No specific ligand binding to p185
HER2
has been identified, although Lupu et al. (
Science
249:1552-1555, 1989) describe an inhibitory 30 kDa glycoprotein secreted from human breast cancer cells which is alleged to be a putative ligand for p185
HER2
. Lupu et al. (
Proceedings of the American Assoc for Cancer Research
, Vol 32, Abs 297, March 1991) reported the purification of a 30 kDa factor from MDA-MB-231 cells and a 75 kDa factor from SK-Br-3 cells that stimulates p185
HER2
. The 75 kDa factor reportedly induced phosphorylation of p186
HER2
and modulated cell proliferation and colony formation of SK-Br-3 cells overexpressing the p186
HER2
receptor. In the rat neu system, Yarden et al. (
Biochemistry
, 30:3543-3550, 1991) describes a 35 kDa glycoprotein candidate ligand for the neu encoded receptor secreted by ras transformed fibroblasts.
Methods for the in vivo assay of tumors using HER2 specific monoclonal antibodies and methods of treating tumor cells using HER2 specific monoclonal antibodies are described in U.S. Ser. No. 07/143,912.
There is a current and continuing need in the art to identify the actual ligand or ligands that activate p185
HER2
, and to identify their biological role(s), including their roles in cell-growth and differentiation, cell-transformation and the creation of malignant neoplasms. While the role of the p185
HER2
and its ligands is unknown in normal cell growth and differentiation, it is an object of the present invention to develop therapeutic uses for the p185
HER2
Holmes William E.
Vandlen Richard L.
Arthur Lisa B.
Genentech Inc.
Lee Wendy M.
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