Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.22 (cdc2)
 8,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mammalian cell cycle progression is regulated by several protein kinases that are activated by cyclically expressed proteins called cyclins. These cyclin-dependent kinases, the prototype of which is the cdc2 mitosis-promoting kinase, are known to phosphorylate substrates the modified status of which is critical for the cell to progress into sequential phases of the cycle. Recently, a new cdc2-related protein kinase has been discovered. PISSLRE, named with respect to its homology to the cdc2 PSTAIRE amino acid domain. Here we report that by using both antisense and dominant-negative mutant constructs of PISSLRE when overexpressed in U2OS cells, a growth suppression is found. Furthermore, the dominant negative forms of PISSLRE halt cell cycle progression in G2-M. Therefore, PISSLRE is essential for cellular proliferation, and its effect is exerted in G2-M. This describes the first evidence since cdc2 of a cdc2-related kinase acting through G2-M.
Cancer Res 1995 Sep 15
PMID:The cdc-2-related kinase, PISSLRE, is essential for cell growth and acts in G2 phase of the cell cycle. 766 69

p21CIP1/WAF1 is a CDK inhibitor regulated by the tumor suppressor p53 and is hypothesized to mediate G1 arrest. p53 has been suggested to derive anti-oncogenic properties from this relationship. To test these notions, we created mice lacking p21CIP1/WAF1. They develop normally and (unlike p53-/- mice) have not developed spontaneous malignancies during 7 months of observation. Nonetheless, p21-/- embryonic fibroblasts are significantly deficient in their ability to arrest in G1 in response to DNA damage and nucleotide pool perturbation. p21-/- cells also exhibit a significant growth alteration in vitro, achieving a saturation density as high as that observed in p53-/- cells. In contrast, other aspects of p53 function, such as thymocytic apoptosis and the mitotic spindle checkpoint, appear normal. These results establish the role of p21CIP1/WAF1 in the G1 checkpoint, but suggest that the anti-apoptotic and the anti-oncogenic effects of p53 are more complex.
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PMID:Mice lacking p21CIP1/WAF1 undergo normal development, but are defective in G1 checkpoint control. 766 46

To better understand the relationship between the proliferation of human lymphoid cells and the expression of cdk1, a catalytic subunit of the histone H1 kinase (H1K), we examined its mRNA and protein content in 3 B-cell lines: Ramos, Reh-6 and IARC 963. Cells were elutriated according to their position in the cell cycle. Cell fractions were analyzed for cdk1 mRNA and protein cellular content by Northern blot and immunoblot, respectively, as well as for H1K activity. Both mRNA and protein amounts and H1K activity varied according to cell cycle phase, the lowest values being observed in G1-enriched fractions. For comparison, elutriated fractions were also tested for the expression of cdk2 and cdk4 proteins. Both showed some variations among fractions, but they were less clear than those of cdk1. We also tested 29 samples of lymphoid neoplastic and non-neoplastic tissues for proliferative activity (percentage of S and G2/M cells estimated by flow cytometry) and expression of cdk1, cdk2 and cdk4 proteins. We found a significant correlation between the percentage of cells in S or S + G2/M phases and cdk1 protein content but not cdk2 or cdk4 content. We conclude that cdk1 expression in human lymphoid cells varies during the cell cycle at both mRNA and protein levels.
Int J Cancer 1995 May 04
PMID:Cdk1 is a marker of proliferation in human lymphoid cells. 772 51

Studies have shown that homozygous deletion of the cyclin-dependent kinase-4 inhibitor (CDK4I) gene, which is mapped to chromosome 9p21, is frequently observed in various types of human cancers. Here we report that the CDK4I gene was deleted in gliomas. Eight cell lines derived from glioblastomas and samples from 14 patients with various grades of gliomas were examined by Southern blot analysis. We found that the CDK4I gene was deleted in 7 of 8 (87.5%) cell lines and 7 of 9 (78%) samples from high-grade glioma patients, whereas it was deleted in 1 of 5 (20%) low-grade glioma samples. These results suggested that inactivation of the CDK4I gene may play an important role in the progression of human glioma.
Jpn J Cancer Res 1995 Apr
PMID:Frequent loss of the cyclin-dependent kinase-4 inhibitor gene in human gliomas. 777 55

The retinoblastoma gene (Rb gene) is a tumour-suppressor gene and its product (pRB) is known to act as a negative regulator of the cell cycle. Although lack of pRB expression resulting from gene alterations is considered to be responsible for the genesis of several human malignancies, increased expression of pRB has been demonstrated in a majority of colorectal cancer cases. In the present study, we investigated the expression of pRB as well as that of its related kinases, cdk2 and cdc2, in colorectal cancer, since these kinases have been reported to phosphorylate and inactivate pRB. Western blot analysis revealed that colorectal cancer expressed higher levels of cdk2 and cdc2 than did normal mucosa and that the ratio of the hyperphosphorylated form of pRB was higher in colorectal cancer. Furthermore, immunohistochemical studies showed that cdk2/cdc2 was expressed exclusively in the cancer cells positive for pRB. These results suggest that an increase in the expression of cdk2/cdc2 in colorectal cancer may have prevented pRB from braking the cell cycle through phosphorylation.
Br J Cancer 1995 Jun
PMID:Coexpression of cdk2/cdc2 and retinoblastoma gene products in colorectal cancer. 777 16

Transforming growth factor beta (TGF beta) acts on epithelial thyroid cells, negatively controlling their proliferation and functions. The effects of TGF beta on epithelial rat thyroid cells (FRTL-5) and on two TGF beta-resistant rat thyroid cell clones (FRTL-5H2 and FRTL-R) were investigated. FRTL-5H2 represents a rat thyroid cell clone overexpressing active erbB-2 oncogene, recently obtained after FRTL-5 cell infection with a retrovirus vector carrying the erbB-2 human oncogene (G. Mincione et al., Cancer Res., 53: 5548-5553, 1993). FRTL-R is a FRTL-5 subclone spontaneously isolated after long term in culture. FRTL-5H2 and FRTL-R cell clones were stimulated by TGF beta at the same concentration of 5 ng/ml that induced 70% inhibition of [3H]thymidine incorporation in control FRTL-5 thyroid cells. Nuclear events regulated by TGF beta, such as cyclin and cyclin-dependent kinase gene expression, were then analyzed. In FRTL-5 cells, TGF beta was found to reduce the expression of cdk2 and cyclin A genes; the same treatment did not modify nuclear gene expression in the resistant cell clones. TGF beta is known to reduce iodide uptake in thyroid cells; in both FRTL-5H2 and FRTL-R cells, TGF beta was found to inhibit the thyrotropin-induced iodide uptake. Thus, thyroid cell clones, resistant to the growth-inhibitory activity of TGF beta, were sensitive to TGF beta inhibition of iodide incorporation, suggesting that TGF beta activates divergent signaling pathways in these cells, separately controlling cell proliferation and differentiation parameters. Studies on TGF beta receptors showed similar amounts of TGF beta-binding species on FRTL-5 cells and TGF beta-resistant clones, while 125I-labeled TGF beta cross-linking experiments revealed differences; thus, the TGF beta-resistant cells showed a 40% decrease in the amount of labeled type II TGF beta receptor on the cell surface. However, this different pattern of TGF beta receptors cannot totally account for the shown TGF beta resistance to growth inhibition that might also be due to perturbation in signaling pathways.
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PMID:Epithelial rat thyroid cell clones, escaping from transforming growth factor beta negative growth control, are still inhibited by this factor in the ability to trap iodide. 779 96

We have studied changes in cyclin A- and B1-dependent kinases during apoptosis induced in human promyelocytic leukemia (HL60) cells treated with the topoisomerase I inhibitor camptothecin. We found that cyclin B1/Cdc2 kinase activity transiently increases within 30 min after camptothecin treatment. This increase is followed by a rapid inactivation of the cyclin B1/Cdc2 kinase that is associated with Cdc2 tyrosine phosphorylation without any change in Cdc2 or cyclin B1 protein levels. The DNA polymerase inhibitor aphidicolin abrogates camptothecin-induced changes in cyclin B1/Cdc2 kinase activity, indicating that DNA replication-induced DNA damage is essential for both Cdc2 alterations and apoptosis activation. Apoptosis and the initial cyclin B1/Cdc2 kinase activation were amplified using synchronized S-phase cells, and cyclin A/cdk2 kinase did not change under these conditions. The same transient activation and subsequent inactivation of cyclin B1/Cdc2 kinase were observed after DNA damage by etoposide or bis-(2-chloroethyl)methylamine hydrochloride. These observations suggest that DNA damage promotes the transient and unscheduled stimulation of cyclin B1/Cdc2 kinase activity in HL60 cells prior to apoptosis.
Cancer Res 1995 Jan 15
PMID:Unscheduled activation of cyclin B1/Cdc2 kinase in human promyelocytic leukemia cell line HL60 cells undergoing apoptosis induced by DNA damage. 781 49

cdk4-mediated phosphorylation of the retinoblastoma susceptibility protein (Rb) is stimulated by cyclin D1, an oncogene, and inhibited by p16, a candidate tumor suppressor. We examined these proteins in non-small cell lung cancer (NSCLC), which is predominantly Rb positive, and small cell lung cancer (SCLC), which is Rb negative. Most NSCLC and SCLC resection specimens and cell lines overexpress cyclin D1 (indicating that cyclin D1 overexpression and Rb inactivation can coexist in SCLC). However, 9 of 9 Rb-positive NSCLC cell lines have absent or low p16, while an Rb-negative NSCLC line and 5 of 5 SCLC cell lines have high levels of p16. In primary resection specimens, p16 was undetectable in 18 of 27 NSCLC samples and abundant in 4 of 5 SCLC samples. Our data confirm the predicted reciprocity between Rb inactivation and p16 expression in a common human malignancy and define differential p16 expression as a fundamental distinction between NSCLC and SCLC.
Cancer Res 1995 Feb 01
PMID:Reciprocal Rb inactivation and p16INK4 expression in primary lung cancers and cell lines. 783 18

Orderly progression through the cell cycle requires sequential activation and inactivation of cyclin-dependent kinases (cdks). This is achieved in part through the association of cdks with positive regulators called cyclins and inactivation of cyclin-cdk complexes by a rapidly growing number of cyclin-cdk inhibitors. Recently, the role of cell cycle control proteins both as primary effectors and as mediators of tumorigenesis has become a subject of increased interest. Here we report the chromosomal mapping of two cdks, cdk3 and cdk6, two putative cdks, PISSLRE and PITALRE, and one cyclin-dependent kinase inhibitor, p27, to chromosomal regions which may be altered in human tumors and examine their possible involvement in some of these malignancies. In particular, two of the kinases, cdk3 and PISSLRE and PITALRE, the cdc2-related kinases recently cloned by us, map to regions previously shown to exhibit loss of heterozygosity in breast and other tumors.
Cancer Res 1995 Mar 15
PMID:Chromosomal mapping of members of the cdc2 family of protein kinases, cdk3, cdk6, PISSLRE, and PITALRE, and a cdk inhibitor, p27Kip1, to regions involved in human cancer. 788 8

The p27Kip1 gene codes for a cyclin-dependent kinase inhibitor implicated in G1 arrest by transforming growth factor beta, cell-cell contact, agents that elevate cyclic AMP, and the growth-inhibitory drug rapamycin. p27 binds to and inhibits complexes formed by cyclin E-cdk2, cyclin A-cdk2, and cyclin D-cdk4. The involvement of p27 in the negative regulation of cell proliferation suggests that it may also function as a tumor suppressor gene. Using a combination of somatic cell hybrid panels and fluorescence in situ hybridization p27Kip1 has been mapped to the short arm of chromosome 12 at the 12p12-12p13.1 boundary, reported to harbor deletions and rearrangements in leukemia and mesotheliomas. In order to assess potential p27Kip1 gene alterations, we have screened a total of 147 human primary solid tumors and found no detectable cancer-specific mutations. These results argue that the often observed loss of antimitogenic transforming growth factor beta responsiveness in human cancer cells is not due to structural defects in p27Kip1.
Cancer Res 1995 Mar 15
PMID:p27Kip1: chromosomal mapping to 12p12-12p13.1 and absence of mutations in human tumors. 788 10


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