Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Colonic neoplasia provides an opportunity to study tumor progression because most carcinomas arise from adenomas (polyps), which, in turn, arise from normal epithelia. The malignant potential of adenomas varies with size, histology, and degree of dysplasia. Polyps that are less than 2 cm with villous architecture and severe dysplasia are most likely to contain carcinoma. Previous studies demonstrated that the in vitro protein-tyrosine kinase activity of pp60c-src from colon carcinomas is significantly higher than that from adjacent normal mucosa. Here we report that the protein kinase activity of pp60c-src is also elevated in colonic polyps. Activity is highest in malignant polyps and in greater than 2-cm benign polyps that contain villous structure and severe dysplasia. Thus, pp60c-src activation occurs in benign polyps that are at greatest risk for developing cancer. These data suggest that activation of the protooncogene product pp60c-src may be an important event in the genesis of human colon carcinoma.
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PMID:Activation of the pp60c-src protein kinase is an early event in colonic carcinogenesis. 210 87

We postulated that increased expression of the cell cycle regulators cyclin D1 and cyclin-dependent kinase (Cdk) 4 may be involved in the development of intestinal adenomas associated with familial adenomatous polyposis (FAP). In the present study of multiple intestinal neoplasia (Min) mice and human FAP patients, the expression and distribution of cyclin D1, Cdk4, and cell proliferative activity (5-bromo-2'-deoxyuridine incorporation) in normal and adenomatous intestinal epithelium were investigated. Immunohistochemical analysis of Min mouse intestine revealed that cyclin D1 immunoreactivity in the intestinal epithelium was restricted to the adenomatous areas, with a significantly higher percentage of positively staining nuclei in high-grade dysplasia versus low-grade dysplasia (54.8 +/- 18.4% versus 34.6 +/- 16.9%, P = 0.016). Morphologically normal areas of intestinal epithelia were uniformly negative for cyclin D1 immunoreactivity. Cdk4 nuclear immunoreactivity was restricted to the crypt areas in morphologically normal small intestine and colon. Conversely, Cdk4 immunoreactivity was uniformly abundant in adenomatous areas regardless of the degree of dysplasia. Increased expression of cyclin D1 and Cdk4 in adenomas was accompanied by a significantly increased 5-bromo-2'-deoxyuridine incorporation rate in the same areas. Immunoblot analysis of lysates from surgical specimens revealed increased levels of cyclin D1 and Cdk4 in the majority of intestinal adenomas from human FAP patients in comparison to the adjacent grossly normal colonic mucosa. Our results indicate that overexpression of cyclin D1 and Cdk4 occurs in intestinal adenomas and is associated with increased cell proliferative activity in premalignant neoplastic cells. Increased cyclin D1 immunoreactivity is associated with more severe dysplasia. These data suggest that abnormal up-regulation of these important G1 cell cycle proteins is a relatively early event in intestinal carcinogenesis and that these changes may contribute to malignant progression within those lesions.
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PMID:Concurrent overexpression of cyclin D1 and cyclin-dependent kinase 4 (Cdk4) in intestinal adenomas from multiple intestinal neoplasia (Min) mice and human familial adenomatous polyposis patients. 898 60

p21WAF1/CIP1 is a nuclear protein that binds to cyclin-dependent kinase complexes (CDKs) and inhibits the activity of multiple kinases. These CDKs are involved in the regulation of cell cycle progression at several checkpoints. In this study, the authors have analyzed by immunohistochemistry the expression of p21WAF1/CIP1 in normal uterine tissues, 12 endometrial hyperplasias, 17 endocervical adenocarcinomas, and 31 endometrial adenocarcinomas. In addition, a group of 10 leiomyomas and 10 uterine leiomyosarcomas were also stained. To evaluate cell proliferation, the monoclonal antibody Ki-67 was used in all of the available cases. Terminally differentiated epithelial endocervical and endometrial cells showed variable expression of p21WAF1/CIP1, whereas the endometrial hyperplasias, and endocervical and endometrial adenocarcinomas showed decreased expression or were negative. All of the cases of cervical squamous dysplasia were positive. Normal smooth muscle cells and 50% of leiomyomas were negative, whereas all leiomyosarcomas showed expression of p21WAF1/CIP1. These results indicate that p21WAF1/CIP1 contributes to differentiation in normal endometrial and endocervical glands. The decreased expression of p21WAF1/CIP1 in endometrial hyperplasias and carcinomas may be important in the process of neoplastic transformation. The role of certain CDK inhibitors, such as p21WAF1/CIP1, is different in epithelial and mesenchymal tumorigenesis in the uterus.
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PMID:Immunohistochemical localization of p21(WAF1/CIP1) in normal, hyperplastic, and neoplastic uterine tissues. 901 33

The radiosensitivity of proliferating crypt epithelial cells makes the gut a major limiting factor in the use of radiotherapy for treatment of abdominal cancers. As post-mitotic epithelial cells migrate from mouse small intestinal crypts to the base of adjacent villi, they rapidly lose their ability to undergo apoptosis in response to ionizing irradiation (IR). To determine whether this radioresistance reflects withdrawal from the cell cycle, we used a lineage-specific promoter to direct expression of wild type Simian virus 40 T antigen (SV40 TAg(Wt)) to villus, but not crypt, enterocytes in FVB/N transgenic mice. SV40 TAg(Wt) induced, pRB-dependent, re-entry into the cell cycle is not associated with the acquisition of IR-stimulated apoptosis 4 h or 24 h after 6 Gy or 12 Gy of gamma-irradiation. Co-expression of SV40 TAg(Wt) and K-ras(val12) produces dysplasia in cycling villus enterocytes but no shift towards apoptotic responsiveness to IR. These findings suggest that the radioresistance of villus enterocytes is not simply due to their cell cycle arrest and may be a reflection of their microenvironment. Remarkably, reentry of villus enterocytes to the cell cycle increases the radiosensitivity of the crypt epithelium without changing Bcl-2, Bcl-xL, Bak, or Bax expression. This effect is only manifest after IR and, based upon results obtained with mutant SV40 TAgs, depends upon reaching a critical level of proliferation in villus enterocytes. Like the normal crypt response to IR, the villus-derived enhancement of IR-stimulated crypt apoptosis is associated with an induction of p53 and Raf-1, and is dependent upon p53. Unlike the normal crypt response to IR, the p53 induction involves cells distributed throughout the crypt and the apoptotic response is not confined to the lower half of the crypt. These results indicate that signals initiated by cycling enterocytes can be transmitted to the crypt epithelium to induce p53 and influence their IR-induced apoptosis. Understanding the underlying signaling pathways may provide clues about how to modify a normal crypt's radiosensitivity for therapeutic benefit.
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PMID:gamma-Ray-induced apoptosis in transgenic mice with proliferative abnormalities in their intestinal epithelium: re-entry of villus enterocytes into the cell cycle does not affect their radioresistance but enhances the radiosensitivity of the crypt by inducing p53. 924 49

Recent studies have shown that the cyclin-dependent kinase (cdk) inhibitors play important roles in cell cycle progression in normal cells. Alterations in the cdk inhibitors also appear to be important in cancer development in a number of human tumors. p27Kip1 is a member of the CIP/KIP family of cdk inhibitors that negatively regulates cyclin-cdk complexes. Reduced levels of p27Kip1 protein have been identified in a number of human cancers, and in some cases reduced p27Kip1 is associated with an increase in proliferative fraction. In the present study, we examined p27Kip1 protein by immunohistochemistry in 10 normal and 36 dysplastic epithelia and in 8 squamous cell carcinomas from one anatomical site within the oral cavity, the floor of the mouth. Proliferative activity was assessed in serial sections by determining the expression of the cell cycle proteins Ki-67 and cyclin A. p27kip1 protein was significantly reduced in oral dysplasias and carcinomas compared with that in normal epithelial controls. In addition, there was a significant reduction in p27Kip1 protein between low- and high-grade dysplasias, suggesting that changes in p27Kip1 expression may be an early event in oral carcinogenesis. There was increasing expression of Ki-67 and cyclin A proteins with increasingly severe grades of dysplasia compared with normal controls. Although there was a strong correlation between Ki-67 and cyclin A scores (r2= 0.61) for all categories of disease, there was a weak negative correlation between Ki-67 and p27Kip1 levels (r2 = 0.29) and between cyclin A and p27Kip1 levels (r2 = 0.25). In conclusion, this study has found that a reduction in the proportion of cells expressing p27Kip1 protein is frequently associated with oral dysplasia and carcinoma from the floor of the mouth. Furthermore, reductions in p27Kip1 levels are associated with increased cell proliferation, although other changes likely contribute to altered cell kinetics during carcinogenesis at this site.
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PMID:Reduced levels of the cell-cycle inhibitor p27Kip1 in epithelial dysplasia and carcinoma of the oral cavity. 946 85

Netherton syndrome (NS [MIM 256500]) is a rare and severe autosomal recessive disorder characterized by congenital ichthyosis, a specific hair-shaft defect (trichorrhexis invaginata), and atopic manifestations. Infants with this syndrome often fail to thrive; life-threatening complications result in high postnatal mortality. We report the assignment of the NS gene to chromosome 5q32, by linkage analysis and homozygosity mapping in 20 families affected with NS. Significant evidence for linkage (maximum multipoint LOD score 10.11) between markers D5S2017 and D5S413 was obtained, with no evidence for locus heterogeneity. Analysis of critical recombinants mapped the NS locus between markers D5S463 and D5S2013, within an <3.5-cM genetic interval. The NS locus is telomeric to the cytokine gene cluster in 5q31. The five known genes encoding casein kinase Ialpha, the alpha subunit of retinal rod cGMP phosphodiesterase, the regulator of mitotic-spindle assembly, adrenergic receptor beta2, and the diastrophic dysplasia sulfate-transporter gene, as well as the 38 expressed-sequence tags mapped within the critical region, are not obvious candidates. Our study is the first step toward the positional cloning of the NS gene. This finding promises a better understanding of the molecular mechanisms that control epidermal differentiation and immunity.
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PMID:Localization of the Netherton syndrome gene to chromosome 5q32, by linkage analysis and homozygosity mapping. 1071 6

The Cdc37 gene encodes a 50 kDa protein which targets intrinsically unstable oncoprotein kinases such as Cdk4, Raf-1, and src to the molecular chaperone Hsp90. This activity is thought to play an important role in the establishment of signaling pathways controlling cell proliferation. The budding yeast Cdc37 homolog is required for cell division and mammalian Cdc37 is expressed in proliferative zones during embryonic development and in adult tissues, consistent with a positive role in proliferation. Here we report that human prostatic tumors, neoplasias and certain pre-malignant lesions display increased Cdc37 expression, suggesting an important and early role for Cdc37 in prostatic transformation. To test the consequences of increased Cdc37 levels, transgenic mice expressing Cdc37 in the prostate were generated. These mice displayed a wide range of growth-related abnormalities including prostatic epithelial cell hyperplasia and dysplasia. These data suggest that the expression of Cdc37 may promote inappropriate proliferation and may be an important early step in the development of human prostate cancer.
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PMID:Induction of human Cdc37 in prostate cancer correlates with the ability of targeted Cdc37 expression to promote prostatic hyperplasia. 1082 68

The cyclin-dependent kinase (cdk) inhibitor, p57 (Kip2) is a tumour suppressor candidate and a paternally-imprinted gene. In humans, the p57(Kip2) gene is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome. From analysis of p57(Kip2)-deficient mice, we demonstrate the relationship between trophoblastic abnormalities and p57(Kip2). Both p57(Kip2) null ((-/-)) embryos and heterozygous embryos with a maternally-derived mutated allele ((+*/-)) displayed placentomegaly, as well as dysplasia of labyrinthine and spongiotrophoblasts. The number of labyrinthine trophoblasts of homozygous embryos was twice that in wild-type embryos. When we measured kinase activities of cdk in total placenta lysates by the immuno complex kinase assay, there were no differences among the genotypes. These results show that p57(Kip2) may function in the proper development of labyrinthine and spongiotrophoblasts by pathways that are not involved with regulation of cdk activities. It is, therefore, suggested that p57(Kip2) protein might have an unknown role.
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PMID:p57(Kip2) regulates the proper development of labyrinthine and spongiotrophoblasts. 1104 65

Dysplasia of the fibrous sheath (DFS) is characterized by male infertility, asthenozoospermia, and morphologically abnormal flagella that possess a severely malformed fibrous sheath. In many cases, DFS is familial, suggesting a genetic component. Human AKAP4 and AKAP3 are structural proteins of the fibrous sheath that also function to anchor protein kinase A to this structure via the regulatory subunit of the kinase. We hypothesized that defects in either AKAP4 or AKAP3 might cause DFS. No quantitative or qualitative differences between patients with DFS and normal controls were detected when sperm proteins were analyzed by either silver staining or immunoblot analysis using antibodies raised against AKAP4 and AKAP3. Additionally, AKAP4 and AKAP3 from DFS sperm retained the ability to bind the regulatory subunit of protein kinase A. Localization at the light and electron microscopic levels showed that AKAP3 and AKAP4 localized correctly to the FS of the amorphous flagellum in DFS sperm. Partial sequence analysis of the AKAP4 and AKAP3 genes in patients with DFS did not identify any significant alterations in potential AKAP4/AKAP3 binding regions, suggesting that the two proteins interact normally in DFS sperm. Our results did not find evidence to support the hypothesis that mutations in either gene are responsible for DFS in humans.
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PMID:Molecular genetic analysis of two human sperm fibrous sheath proteins, AKAP4 and AKAP3, in men with dysplasia of the fibrous sheath. 1122 5

Molecular and kinetic analyses have contributed to our understanding of the biology of transitional cell carcinomas (TCC) of the bladder. The concordant pattern of X-chromosome inactivation of multiple TCCs appearing at different times and at different sites and concordant genetic abnormalities in a subset of muscle-invasive TCC strongly support a monoclonal origin and a homogeneous tumor cell selection throughout the neoplasm. However, topographic intratumor heterogeneity results from the accumulation of genetic lesions in tumor suppressor genes, predominantly neurofibromatosis (NF)-1-defective in the superficial compartment and tumor protein p53 (TP53)-defective in the deep one, with lower proliferation and down-regulation of apoptosis in the latter. TCCs follow the general concept of multistep carcinogenesis and proceed through two distinct genetic pathways responsible for generating different TCC morphologies. These are the inactivation of cyclin-dependent kinase inhibitors (p15, p16, and p21WAF/CIP1) in low-grade TCC and early TP53-mediated abnormalities in high-grade TCC. TCC progression correlates with genetic instability and accumulation of collaborative genetic lesions mainly involving TP53, retinoblastoma (RB)-1, and growth factors. Distinctive genetic (low incidence of RB-1 and NF-1 abnormalities) and kinetic (slower cell turnover) profiles also correlate with a "single-file" infiltration pattern and poor survival in muscle-invasive TCCs. The underlying molecular changes of carcinoma in situ involve multiple and more extensive deletions (normally TP53-defective) than coexistent invasive TCC, suggesting an independent genetic evolution, while low-grade dysplasia is mainly polyclonal and shows a low rate of gene deletions.
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PMID:Molecular and kinetic features of transitional cell carcinomas of the bladder: biological and clinical implications. 1131 26


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