D-type cyclins, in association with the cyclin-dependent kinases Cdk4 or Cdk6, promote progression through the G1 phase of the cell cycle by phosphorylating the retinoblastoma protein (RB). The activities of Cdk4 and Cdk6 are constrained by inhibitors such as p16, the product of the CDKN2 gene on human chromosome 9p21 (refs 12-14). The frequent deletion or mutation of CDKN2 in tumour cells suggests that p16 acts as a tumour suppressor. We show that wild-type p16 arrests normal diploid cells in late G1, whereas a tumour-associated mutant of p16 does not. Significantly, the ability of p16 to induce cell-cycle arrest is lost in cells lacking functional RB, including primary fibroblasts from Rb-/- mouse embryos. Thus, loss of p16, overexpression of D-cyclins and loss of RB have similar effects on G1 progression, and may represent a common pathway to tumorigenesis.

• MeSH
• buněčný cyklus * fyziologie   MeSH
• cyklin D1 MeSH
• cyklin-dependentní kinasa 4 MeSH
• cyklin-dependentní kinasa 6 MeSH
• cyklin-dependentní kinasy * MeSH
• cykliny fyziologie   MeSH
• Escherichia coli MeSH
• G1 fáze fyziologie   MeSH
• inhibitor p16 cyklin-dependentní kinasy MeSH
• klonování DNA MeSH
• kultivované buňky MeSH
• lidé MeSH
• mikroinjekce MeSH
• mutace MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• nádorové buňky kultivované MeSH
• onkogenní proteiny fyziologie   MeSH
• protein-serin-threoninkinasy antagonisté a inhibitory   MeSH
• protoonkogenní proteiny * MeSH
• rekombinantní proteiny metabolismus   MeSH
• retinoblastomový protein * fyziologie   MeSH
• transportní proteiny fyziologie   genetika   MeSH
• tumor supresorové geny * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

To explore regulation and function of cyclin D2, a candidate cell cycle-regulatory proto-oncogene, we examined subcellular localisation, cell type- and cell cycle-dependent expression, and requirement of cyclin D2 protein for G1 progression, in a panel of 40 human normal and cancer cell types. Except for lymphoid cells and sarcoma cell lines, expression of cyclin D2 was considerably more restricted than that of cyclin D1, whereas both D-type cyclin proteins were low or undetectable in cells lacking functional retinoblastoma gene product. In G1 cells, the cyclin D2 protein was more resistant to extraction and localised predominantly to nuclei, whereas it became more soluble and distributed in both nuclei and cytoplasm from G1/S transition onwards. Centrifugal elutriation and multiparameter flow cytometry analyses of several cell types showed moderate cell cycle oscillation with maximum levels of the cyclin D2 protein reached in late G1. Microinjection and/or electroporation of antibodies to cyclin D2 during G1 arrested the cyclin D2-expressing lymphocytes, breast myoepithelium, and U-2-OS sarcoma cells in G1 phase, whereas cyclin D2-negative cell types were unaffected by such treatment. Consistent with the putative proto-oncogenic role of cyclin D2 in specific cell types, our data show that this G1 cyclin has properties closely resembling those of cyclin D1, including the essential positive role in regulation of G1.

• MeSH
• buněčné linie MeSH
• cyklin D1 MeSH
• cyklin D2 MeSH
• cykliny fyziologie   imunologie   MeSH
• G1 fáze * fyziologie   MeSH
• lidé MeSH
• monoklonální protilátky imunologie   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• nádorové buňky kultivované MeSH
• nukleoproteiny fyziologie   imunologie   MeSH
• onkogenní proteiny fyziologie   MeSH
• subcelulární frakce metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Mantle cell lymphoma (MCL) is a clinicopathologic entity that is difficult to diagnose on histopathologic criteria. Approximately 50% to 70% of MCL contain a t(11;14)(q13;q32) translocation involving the cyclin D1 gene. Irrespective of this rearrangement, almost all MCL show overexpression of the cyclin D1 gene at the mRNA level. Other B-cell non-Hodgkin's lymphomas (NHL) do not show this rearrangement or overexpression of cyclin D1. We developed an immunohistochemical assay to detect overexpression of the cyclin D1 protein on conventional formalin-fixed, paraffin-embedded biopsies using the well-defined monoclonal antibody DCS-6. Expression in tumor cells was compared with expression of cyclin D1 in endothelial cells and fibroblasts. An exclusively nuclear staining pattern was observed. Moreover, expression was directly compared with the expression observed by immunoblot analysis with the same antibody, as well as with mRNA expression and with the occurrence of genomic rearrangements within the BCL-1 locus. Of 13 MCL that were analyzed by immunohistochemistry and immunoblot, 12 showed overexpression with both techniques, whereas no overexpression was observed in 39 other NHL. Of 13 additional MCL studied either by immunohistochemistry or immunoblot, 11 also showed overexpression. Two lymphomas morphologically indistinguishable from MCL but with an aberrant immunophenotype (CD5 negative, CD10 positive) both lacked overexpression of cyclin D1. These results underscore the significance of overexpression of the cyclin D1 protein as a specific marker for MCL. Detection of cyclin D1 overexpression on formalin-fixed, paraffin-embedded tissues using the DCS-6 monoclonal antibody can be applied for routine diagnostic purposes.

• MeSH
• biopsie MeSH
• buněčné jádro chemie   MeSH
• cyklin D1 MeSH
• cykliny analýza   genetika   MeSH
• exprese genu MeSH
• imunoblotting MeSH
• imunohistochemie MeSH
• lidé MeSH
• messenger RNA metabolismus   MeSH
• monoklonální protilátky MeSH
• nádorové biomarkery analýza   MeSH
• nehodgkinský lymfom diagnóza   metabolismus   MeSH
• northern blotting MeSH
• onkogenní proteiny analýza   genetika   MeSH
• protoonkogenní proteiny genetika   MeSH
• translokace genetická MeSH
• zalévání tkání MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

In this paper we describe how research on the mouse mammary tumor virus model of breast cancer resulted in the identification of an amplified region of DNA on human chromosome 11 band q13. This amplification occurs in approximately 15% of primary breast cancers. Several candidate oncogenes map within the amplicon but by analysing expression of these genes a strong case can be made for a role for cyclin D1 in tumorigenesis. Immunohistochemical staining indicates that cyclin D1 is expressed at elevated levels in around 40% of breast cancers, including those with the 11q13 amplification. The potential function of cyclin D1 as a regulator of early cell division cycle events would be consistent with a role in neoplasia.

• MeSH
• amplifikace genu MeSH
• cyklin D1 MeSH
• cykliny fyziologie   MeSH
• lidé MeSH
• lidské chromozomy, pár 11 genetika   MeSH
• nádory prsu genetika   MeSH
• onkogenní proteiny fyziologie   MeSH
• Southernův blotting MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Immunohistochemical staining with a monoclonal antibody against human cyclin D1 can be used to identify breast cancers that have an amplification of the q13 region of chromosome 11. In general, the intensity of staining is directly proportional to the degree of DNA amplification. In two unusual tumors, in which the CCND1 locus is highly amplified but staining is relatively weak, it appears that the DNA has undergone rearrangement and that the amplified/rearranged CCND1 allele may have reduced transcriptional activity. More significantly, the immunohistochemical technique identifies additional tumors in which the cyclin D1 gene is overexpressed with only marginal or undetectable increases in copy number, implying that other mechanisms can lead to deregulated expression. These results suggest that the frequency of overexpression is much higher than previously concluded from DNA-based analyses and that more than one-third of human breast cancers may contain excessive levels of cyclin D1. The technique we describe should facilitate the detection of this abnormality in a clinical setting and clarify its prognostic significance.

• MeSH
• alely MeSH
• amplifikace genu * MeSH
• cyklin D1 MeSH
• cykliny analýza   biosyntéza   genetika   MeSH
• DNA nádorová analýza   metabolismus   MeSH
• exprese genu MeSH
• genetická transkripce MeSH
• imunohistochemie MeSH
• lidé MeSH
• lidské chromozomy, pár 11 * MeSH
• mapování chromozomů MeSH
• monoklonální protilátky MeSH
• nádorové buňky kultivované MeSH
• nádory prsu metabolismus   patologie   MeSH
• onkogenní proteiny analýza   biosyntéza   genetika   MeSH
• prognóza MeSH
• RNA nádorová analýza   biosyntéza   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH