Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving nucleic acid
Reexamination Certificate
2001-06-11
2003-06-24
Horlick, Kenneth R. (Department: 1637)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving nucleic acid
C435S040520, C435S091100, C435S091200, C536S023100, C536S023500, C536S024330
Reexamination Certificate
active
06582919
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to prognostic methods which are useful in medicine, particularly cancer chemotherapy. More particularly, the invention relates to assessment of surviviability of a patient whose tumor cell gene expression is analyzed. Additionally, the sensitivity of tumor cells to receptor tyrosine kinase targeted chemotherapeutic regimen is assayed by examining the mRNA expression of the EGFR and Her2-neu genes in humans.
BACKGROUND OF THE INVENTION
Lung cancer is the leading cause of cancer-related deaths among both males and females in western countries. In the United States, approximately 171,000 new cases of lung cancer are diagnosed and 160,000 individuals die from this disease each year. Despite improvements in the detection and treatment of lung cancer in the past two decades, the overall 5-year survival remains less than 15%. Ginsberg, et al., In: DeVita, et al.,
Cancer: Principles in Practice of Oncology
, Ed. 5, pp. 858-910. Philadelphia Lipincott-Raven Publishers, 1997. To further improve the survival rate in patients with Non-Small Cell Lung Carcinoma (NSCLC), their prognostic classification based on molecular alterations is crucial. Such classification will provide more accurate and useful diagnostic tools and, eventually, more effective therapeutic options.
Cancer arises when a normal cell undergoes neoplastic transformation and becomes a malignant cell. Transformed (malignant) cells escape normal physiologic controls specifying cell phenotype and restraining cell proliferation. Transformed cells in an individual's body thus proliferate, forming a tumor. When a tumor is found, the clinical objective is to destroy malignant cells selectively while mitigating any harm caused to normal cells in the individual undergoing treatment.
Chemotherapy is based on the use of drugs that are selectively toxic (cytotoxic) to cancer cells. Several general classes of chemotherapeutic drugs have been developed, including drugs that interfere with nucleic acid synthesis, protein synthesis, and other vital metabolic processes. These generally are referred to as anti-metabolite drugs. Other classes of chemotherapeutic drugs inflict damage on cellular DNA. Drugs of these classes generally are referred to as genotoxic. Additionally, a class of chemotherapeutic agents specifically inhibit mitogenic signaling through receptor tyrosine kinases (RTKs), in cells where RTKs are over active. (Drugs of the Future, 1992, 17, 119).
Susceptibility of an individual neoplasm to a desired chemotherapeutic drug or combination of drugs often, however, can be accurately assessed only after a trial period of treatment. The time invested in an unsuccessful trial period poses a significant risk in the clinical management of aggressive malignancies. Therefore, it is of importance to assess the expression status of genetic determinants targeted by specific chemotherapeutic agents. For example, if a tumor expresses high levels of DNA repair genes, it is likely that the tumor will not respond well to low doses of DNA-damaging genotoxic agents. Thus, the expression status of genetic determinants of a tumor will help the clinician develop an appropriate chemotherapeutic regimen specific to the genetic repertoire of the tumor.
Receptor tyrosine kinases (RTKs) are important in the transduction of mitogenic signals. RTKs are large membrane spanning proteins which possess an extracellular ligand binding domain for growth factors such as epidermal growth factor (EGF) and an intracellular portion which functions as a kinase to phosphorylate tyrosine amino acid residues on cytosol proteins thereby mediating cell proliferation. Various classes of receptor tyrosine kinases are known based on families of growth factors which bind to different receptor tyrosine kinases. (Wilks, Advances in Cancer Research, 1993, 60, 43-73)
Class I kinases such as the EGF-R family of receptor tyrosine kinases include the EGF, HER2-neu, erbB, Xmrk, DER and let23 receptors. These receptors are frequently present in common human cancers such as breast cancer (Sainsbury et al., Brit. J. Cancer, 1988, 58, 458; Guerin et al., Oncogene Res., 1988, 3, 21), squamous cell cancer of the lung (Hendler et al., Cancer Cells, 1989, 7, 347), bladder cancer (Neal et al., Lancet, 1985, 366), oesophageal cancer (Mukaida et al, Cancer, 1991, 68, 142), gastrointestinal cancer such as colon, rectal or stomach cancer (Bolen et al., Oncogene Res., 1987, 1, 149), leukaemia (Konaka et al., Cell, 1984, 37, 1035) and ovarian, bronchial or pancreatic cancer (European Patent Specification No. 0400586). As further human tumor tissues are tested for the EGF family of receptor tyrosine kinases it is expected that its widespread prevalence will be established in other cancers such as thyroid and uterine cancer.
Specifically, EGFR tyrosine kinase activity is rarely detected in normal cells whereas it is more frequently detectable in malignant cells (Hunter, Cell, 1987, 50, 823). It has been more recently shown that EGFR is overexpressed in many human cancers such as brain, lung squamous cell, bladder, gastric, breast, head and neck, oesophageal, gynaecological and thyroid tumours. (W J Gullick, Brit. Med. Bull., 1991, 47, 87). Receptor tyrosine kinases are also important in other cell-proliferation diseases such as psoriasis. EGFR disorders are those characterized by EGFR expression by cells normally not expressing EGFR, or increased EGFR activation leading to unwanted cell proliferation, and/or the existence of inappropriate EGFR levels. The EGFR is known to be activated by its ligand EGF as well as transforming growth factor-alpha (TGF-&agr;).
The Her2-neu protein is also a member of the class I receptor tyrosine kinase (RTK) family. Yarden and Ullrich, Annu. Rev. Biochem. 57:443, 1988; Ullrich and Schlessinger, Cell 61:203, 1990. Her2-neu protein is structurally related to EGFR. Carraway, et al., Cell 78:5, 1994; Carraway, et al., J. Biol. Chem. 269:14303, 1994. These receptors share a common molecular architecture and contain two cysteine-rich regions within their cytoplasmic domains and structurally related enzymatic regions within their cytoplasmic domains.
Ligand-dependent activation of Her2-neu protein is thought to be mediated by neuactivating factor (NAF) which can directly bind to p165(Her2-neu) and stimulate enzymatic activity. Dougall et al., Oncogene 9:2109, 1994; Samata et al., Proc. Natl. Acad. Sci. USA 91:1711, 1994. Ligand-independent homodimerization of Her2-neu protein and resulting receptor activation is facilitated by over-expression of Her2-neu protein. An activated Her2-neu complex acts as a phosphokinase and phosphorylates different cytoplasmic proteins. HER2-neu disorders are characterized by inappropriate activity or over-activity of HER2-neu have increased HER2-neu expression leading to unwanted cell proliferation such as cancer.
Inhibitors of receptor tyrosine kinases EGFR and HER2-neu are employed as selective inhibitors of the growth of mammalian cancer cells (Yaish et al. Science, 1988, 242, 933). For example, erbstatin, an EGF receptor tyrosine kinase inhibitor, reduced the growth of EGFR expressing human mammary carcinoma cells injected into athymic nude mice, yet had no effect on the growth of tumors not expressing EGFR. (Toi et al., Eur. J. Cancer Clin. Oncol., 1990, 26, 722.) Various derivatives of styrene are also stated to possess tyrosine kinase inhibitory properties (European Patent Application Nos. 0211363, 0304493 and 0322738) and to be of use as anti-tumour agents. Two such styrene derivatives are Class I RTK inhibitors whose effectiveness has been demonstrated by attenuating the growth of human squamous cell carcinoma injected into nude mice (Yoneda et al., Cancer Research, 1991, 51, 4430). It is also known from European Patent Applications Nos. 0520722 and 0566226 that certain 4-anilinoquinazoline derivatives are useful as inhibitors of receptor tyrosine kinases. The very tight structure-activity relationships shown by these compounds suggests a clearly-defined binding mode, where the
Horlick Kenneth R.
Response Genetics, Inc.
Spiegler Alexander H.
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