Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or...
Reexamination Certificate
1999-05-14
2003-01-28
Priebe, Scott D. (Department: 1632)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
C435S006120, C435S021000, C435S325000, C435S366000
Reexamination Certificate
active
06511799
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention is related to the area of cancer. More particularly it is related to the area of genetic and biochemical targets involved in cancer development.
BACKGROUND OF THE INVENTION
Mutations in the adenomatous polyposis coli (APC) gene initiate the vast majority of human colorectal tumors (Kinzler and Vogelstein, 1996) but the functional consequences of such mutations at the biochemical level were until recently poorly understood. An important advance was made with the discovery that the APC gene product inhibits &bgr;-catenin/TCF regulated transcription (CRT) (Korinek et al., 1997, Morin et al., 1997). This inhibition is likely mediated by the binding of &bgr;-catenin to APC (Rubinfeld et al., 1993, Su et al., 1993), which facilitates phosphorylation of &bgr;-catenin by GSK-3&bgr; (Rubinfeld et al., 1996), and leads to its degradation through ubiquitination-dependent proteolysis (Munemitsu et al., 1995, Aberle et al., 1997, Orford et al., 1997). APC thus effectively regulates the cellular levels of &bgr;-catenin and consequently the formation of active transcription complexes between &bgr;-catenin and Tcf-4. Consistent with this model, alterations of &bgr;-catenin that render it refractory to regulation by APC were identified in a number of tumors with wild-type APC (Morin et al., 1997, Rubinfeld et al., 1996, Sparks et al., 1998), and it was shown that these &bgr;-catenin mutations as well as inactivating mutations of APC result in constitutive CRT (Morin et al., 1997). Accordingly, previous work had shown that all colorectal cancer cell lines tested had constitutive CRT (Korinek et al., 1997), suggesting that CRT deregulation is a key event in colorectal cancer initiation.
There is a continuing need in the art for identification of components of the CRT pathway and of other key pathways in the development of cancers.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide methods for screening substances as candidate drugs for treating human cancers with mutant APC alleles.
It is another object of the present invention to provide methods of ameliorating the effects of APC mutations on human cells.
It is an object of the present invention to provide a method of preventing tumors in patients with Familial Adenomatous Polyposis.
Another object of the invention is to provide methods for detecting APC mutations.
These and other objects of the invention are achieved by providing one or more of the following embodiments. In one embodiment of the invention a method is provided for screening substances as candidate drugs for treating human cancers with mutant APC alleles. A human cell is contacted with a test substance. A CDX2 gene product selected from the group consisting of CDX2 mRNA and CDX2 protein is measured in the human cell. A test substance which increases expression in the cell of the CDX2 gene product is a candidate drug for treating human cancers with mutant APC alleles.
According to another embodiment of the invention a method is provided for screening substances as candidate drugs for treating human cancers with mutant APC alleles. A human cell is contacted with a test substance. A gene product of a CDX2-responsive gene is measured in the human cell. The gene product is selected from the group consisting of mRNA and protein. A test substance which increases expression in the cell of the CDX2-responsive gene product is a candidate drug for treating human cancers with mutant APC alleles.
According to still another embodiment a method is provided for screening substances as candidate drugs for treating human cancers with mutant APC alleles. A human cell comprising a CDX2-responsive reporter construct is contacted with a test substance. A gene product of the reporter construct selected from the group consisting of mRNA and protein is measured. A test substance which increases expression in the cell of the reporter is a candidate drug for treating colorectal cancer.
Yet another aspect of the invention is a method of ameliorating the effects of APC mutations on human cells. A human wild-type CDX2 coding sequence is administered to human cells comprising mutant APC alleles. As a result, expression of CDX2 is upregulated.
Still another aspect of the invention is a method of preventing tumors in patients with Familial Adenomatous Polyposis. A human wild-type CDX2 coding sequence is administered to intestinal cells of a human with Familial Adenomatous Polyposis. As a result, expression of CDX2 is upregulated in the intestinal cells, thereby preventing or reducing the incidence of formation of tumors in the human.
According to still another embodiment of the invention a method is provided for detecting APC mutations. Expression of a human CDX2 gene product selected from the group consisting of CDX2 mRNA and CDX2 protein, is measured in a test sample comprising human cells. The measured expression in the test sample is compared to expression in a normal human control sample. Diminished expression of the human CDX2 gene product in the test sample relative to the normal control sample suggests that the test sample comprises mutant APC alleles.
Another diagnostic aspect of the invention is a method for detecting APC mutations. Expression of a human CDX2-responsive gene product selected from the group consisting of mRNA and protein, is measured in a test sample. The measured expression in the test sample is compared to expression in a nomal control sample. Diminished expression of the human CDX2-responsive gene product in the test sample relative to the nomal control sample suggests that the test sample comprises mutant APC alleles.
Another diagnostic embodiment of the invention provides a method for detecting APC mutations. Expression of a human CDX2-responsive reporter gene product selected from the group consisting of mRNA and protein in a test sample comprising human cells is measured. The measured expression in the test sample is compared to expression in a nomal human control sample. Diminished expression of the human CDX2-responsive reporter gene product in the test sample relative to the nomal human control sample suggests that the test sample comprises mutant APC alleles.
These and other embodiments of the invention which are described in more detail below provide the art with a new therapeutic target for fighting cancers.
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Suh and Traber “An Intestine-Specific Homeobox Gene Regulates Pro
daCosta Luis
He Tong-Chuan
Kinzler Kenneth W
Vogelstein Bert
Banner & Witcoff , Ltd.
Chen Shin-Lin
Priebe Scott D.
The Johns Hopkins University
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