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Wigginton J, Hixon J, Stauffer J, Lincoln E, Back T, Brenner J, Lockett S, Nagashima K, Khan T. 275 Interleukin-12 inhibits AKT phosphorylation and upregulates cleavage and subcellular translocation of EGFP-bid within murine neuroblastoma tumors. EJC Suppl 2004. [DOI: 10.1016/s1359-6349(04)80283-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Krtolica A, Parrinello S, Lockett S, Desprez PY, Campisi J. Senescent fibroblasts promote epithelial cell growth and tumorigenesis: a link between cancer and aging. Proc Natl Acad Sci U S A 2001; 98:12072-7. [PMID: 11593017 PMCID: PMC59769 DOI: 10.1073/pnas.211053698] [Citation(s) in RCA: 1180] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Indexed: 11/18/2022] Open
Abstract
Mammalian cells can respond to damage or stress by entering a state of arrested growth and altered function termed cellular senescence. Several lines of evidence suggest that the senescence response suppresses tumorigenesis. Cellular senescence is also thought to contribute to aging, but the mechanism is not well understood. We show that senescent human fibroblasts stimulate premalignant and malignant, but not normal, epithelial cells to proliferate in culture and form tumors in mice. In culture, the growth stimulation was evident when senescent cells comprised only 10% of the fibroblast population and was equally robust whether senescence was induced by replicative exhaustion, oncogenic RAS, p14(ARF), or hydrogen peroxide. Moreover, it was due at least in part to soluble and insoluble factors secreted by senescent cells. In mice, senescent, much more than presenescent, fibroblasts caused premalignant and malignant epithelial cells to form tumors. Our findings suggest that, although cellular senescence suppresses tumorigenesis early in life, it may promote cancer in aged organisms, suggesting it is an example of evolutionary antagonistic pleiotropy.
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Affiliation(s)
- A Krtolica
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Abstract
In this paper, we use partial-differential-equation-based filtering as a preprocessing and post processing strategy for computer-aided cytology. We wish to accurately extract and classify the shapes of nuclei from confocal microscopy images, which is a prerequisite to an accurate quantitative intranuclear (genotypic and phenotypic) and internuclear (tissue structure) analysis of tissue and cultured specimens. First, we study the use of a geometry-driven edge-preserving image smoothing mechanism before nuclear segmentation. We show how this filter outperforms other widely-used filters in that it provides higher edge fidelity. Then we apply the same filter, with a different initial condition, to smooth nuclear surfaces and obtain sub-pixel accuracy. Finally we use another instance of the geometrical filter to correct for misinterpretations of the nuclear surface by the segmentation algorithm. Our prefiltering and post filtering nicely complements our initial segmentation strategy, in that it provides substantial and measurable improvement in the definition of the nuclear surfaces.
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Affiliation(s)
- A Sarti
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
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Lieb JD, de Solorzano CO, Rodriguez EG, Jones A, Angelo M, Lockett S, Meyer BJ. The Caenorhabditis elegans dosage compensation machinery is recruited to X chromosome DNA attached to an autosome. Genetics 2000; 156:1603-21. [PMID: 11102361 PMCID: PMC1461385 DOI: 10.1093/genetics/156.4.1603] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dosage compensation machinery of Caenorhabditis elegans is targeted specifically to the X chromosomes of hermaphrodites (XX) to reduce gene expression by half. Many of the trans-acting factors that direct the dosage compensation machinery to X have been identified, but none of the proposed cis-acting X chromosome-recognition elements needed to recruit dosage compensation components have been found. To study X chromosome recognition, we explored whether portions of an X chromosome attached to an autosome are competent to bind the C. elegans dosage compensation complex (DCC). To do so, we devised a three-dimensional in situ approach that allowed us to compare the volume, position, and number of chromosomal and subchromosomal bodies bound by the dosage compensation machinery in wild-type XX nuclei and XX nuclei carrying an X duplication. The dosage compensation complex was found to associate with a duplication of the right 30% of X, but the complex did not spread onto adjacent autosomal sequences. This result indicates that all the information required to specify X chromosome identity resides on the duplication and that the dosage compensation machinery can localize to a site distinct from the full-length hermaphrodite X chromosome. In contrast, smaller duplications of other regions of X appeared to not support localization of the DCC. In a separate effort to identify cis-acting X recognition elements, we used a computational approach to analyze genomic DNA sequences for the presence of short motifs that were abundant and overrepresented on X relative to autosomes. Fourteen families of X-enriched motifs were discovered and mapped onto the X chromosome.
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Affiliation(s)
- J D Lieb
- Howard Hughes Medical Institute and University of California, Berkeley, California 94720-3204, USA
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Gray J, Chin K, Collins C, Yaswin P, Nonet G, Kowbel D, Kuo WL, Garcia E, Ortiz de Solorzano C, Knowles D, Lockett S, Bissell M, Weaver V, Pinkel D, Albertson D, Børresen-Dale AL, Waldnian F. Two molecular cytogenetic views of breast cancer. Breast Cancer Res 2000. [PMCID: PMC3300893 DOI: 10.1186/bcr195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- J Gray
- UCSF Cancer Center, University of California, San Francisco
| | - K Chin
- UCSF Cancer Center, University of California, San Francisco
| | - C Collins
- UCSF Cancer Center, University of California, San Francisco
| | - P Yaswin
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - G Nonet
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - D Kowbel
- UCSF Cancer Center, University of California, San Francisco
| | - W-L Kuo
- UCSF Cancer Center, University of California, San Francisco
| | - E Garcia
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - C Ortiz de Solorzano
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - D Knowles
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - S Lockett
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - M Bissell
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - V Weaver
- Biomedical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - D Pinkel
- UCSF Cancer Center, University of California, San Francisco
| | - D Albertson
- UCSF Cancer Center, University of California, San Francisco
| | - A-L Børresen-Dale
- Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - F Waldnian
- UCSF Cancer Center, University of California, San Francisco
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Krauss SW, Larabell CA, Lockett S, Gascard P, Penman S, Mohandas N, Chasis JA. Structural protein 4.1 in the nucleus of human cells: dynamic rearrangements during cell division. J Cell Biol 1997; 137:275-89. [PMID: 9128242 PMCID: PMC2139783 DOI: 10.1083/jcb.137.2.275] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/1996] [Revised: 01/20/1997] [Indexed: 02/04/2023] Open
Abstract
Structural protein 4.1, first identified as a crucial 80-kD protein in the mature red cell membrane skeleton, is now known to be a diverse family of protein isoforms generated by complex alternative mRNA splicing, variable usage of translation initiation sites, and posttranslational modification. Protein 4.1 epitopes are detected at multiple intracellular sites in nucleated mammalian cells. We report here investigations of protein 4.1 in the nucleus. Reconstructions of optical sections of human diploid fibroblast nuclei using antibodies specific for 80-kD red cell 4.1 and for 4.1 peptides showed 4.1 immunofluorescent signals were intranuclear and distributed throughout the volume of the nucleus. After sequential extractions of cells in situ, 4.1 epitopes were detected in nuclear matrix both by immunofluorescence light microscopy and resinless section immunoelectron microscopy. Western blot analysis of fibroblast nuclear matrix protein fractions, isolated under identical extraction conditions as those for microscopy, revealed several polypeptide bands reactive to multiple 4.1 antibodies against different domains. Epitope-tagged protein 4.1 was detected in fibroblast nuclei after transient transfections using a construct encoding red cell 80-kD 4.1 fused to an epitope tag. Endogenous protein 4.1 epitopes were detected throughout the cell cycle but underwent dynamic spatial rearrangements during cell division. Protein 4.1 was observed in nucleoplasm and centrosomes at interphase, in the mitotic spindle during mitosis, in perichromatin during telophase, as well as in the midbody during cytokinesis. These results suggest that multiple protein 4.1 isoforms may contribute significantly to nuclear architecture and ultimately to nuclear function.
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Affiliation(s)
- S W Krauss
- Life Sciences Division, University of California, Lawrence Berkeley National Laboratory, 94720, USA
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Liang XH, Mungal S, Ayscue A, Meissner JD, Wodnicki P, Hockenbery D, Lockett S, Herman B. Bcl-2 protooncogene expression in cervical carcinoma cell lines containing inactive p53. J Cell Biochem 1995; 57:509-21. [PMID: 7768985 DOI: 10.1002/jcb.240570316] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bcl-2 protein expression has been found to block apoptosis and its overexpression has been implicated in lymphoid malignancies where the chromosomal translocation t(14;18) is present. In this study we investigated bcl-2 transcription and protein expression in cultured cervical carcinoma cell lines and keratinocytes. Western blotting and immunofluorescence microscopy demonstrated bcl-2 expression in the cytoplasm of 4 out of 5 cervical carcinoma cell lines examined (HeLa, CaSki, C-33A, and HT-3, but not SiHa). Bcl-2 protein expression was undetectable in normal keratinocytes. None of the cell lines examined demonstrated chromosomal translocation or rearrangement at the major breakpoint-cluster region (MBR) of the bcl-2 gene using either Southern blot or polymerase chain reaction (PCR) analyses. Northern blot analysis demonstrated low levels of bcl-2 transcription in HeLa, CaSki, and C-33A cell lines while reverse transcriptase (RT)-PCR demonstrated bcl-2 transcription in all cervical carcinoma cell lines which had bcl-2 protein expression. Thus, these data suggest that bcl-2 expression occurs in cervical carcinoma cell lines in the absence of chromosomal translocation or rearrangement of the bcl-2 gene. However, each of these cervical carcinoma cell lines contains inactive p53, either due to mutation (C-33A and HT-3) or via complexation and degradation with human papillomavirus (HPV) 16/18 E6 protein (HeLa and CaSki). Thus, functional p53, which can induce apoptosis in certain cells, is not present in these cervical cells which have increased bcl-2 expression. Increased bcl-2 expression under conditions of p53 inactivation may provide cells with a selective advantage for survival and consequently play a role in the development of cervical carcinogenesis.
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Affiliation(s)
- X H Liang
- Laboratory for Cell Biology, School of Medicine, University of North Carolina at Chapel Hill 27599, USA
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Lockett S. Management of gout. Practitioner 1991; 235:263-7. [PMID: 1906615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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