901
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Ohtani N, Yamakoshi K, Takahashi A, Hara E. The p16INK4a-RB pathway: molecular link between cellular senescence and tumor suppression. THE JOURNAL OF MEDICAL INVESTIGATION 2004; 51:146-53. [PMID: 15460900 DOI: 10.2152/jmi.51.146] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The p16INK4a tumor suppressor protein functions as an inhibitor of CDK4 and CDK6, the D-type cyclin-dependent kinases that initiate the phosphorylation of the retinoblastoma tumor suppressor protein, RB. Thus, p16INK4a has the capacity to arrest cells in the G1-phase of the cell cycle and its probable physiological role is in the implementation of irreversible growth arrest termed cellular senescence. Cellular senescence is a state of permanent growth arrest that can be induced by a variety of stresses such as DNA-damage and aberrant mitogenic signaling in human primary cells. In contrast to normal cells, the function of the p16INK4a gene or its downstream mediators is frequently deregulated in many types of human cancers, illustrating the importance of cellular senescence in tumor suppression. Here we discuss the molecular mechanisms that direct cellular senescence and reveal its potential for tumor suppression.
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Affiliation(s)
- Naoko Ohtani
- Division of Protein Information, Institute for Genome Research, The University of Tokushima, Tokushima, Japan
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902
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Wang SW, Pan SL, Guh JH, Chen HL, Huang DM, Chang YL, Kuo SC, Lee FY, Teng CM. YC-1 [3-(5'-Hydroxymethyl-2'-furyl)-1-benzyl Indazole] exhibits a novel antiproliferative effect and arrests the cell cycle in G0-G1 in human hepatocellular carcinoma cells. J Pharmacol Exp Ther 2004; 312:917-25. [PMID: 15525795 DOI: 10.1124/jpet.104.077230] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
This study delineates the antiproliferative activities and in vivo efficacy of YC-1 [3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole] in human hepatocellular carcinoma cells. YC-1 inhibited the growth of HA22T and Hep3B cells in a concentration-dependent manner without significant cytotoxicity. YC-1 induced G(1) phase arrest in the cell cycle, as detected by an increase in the proportion of cells in the G(1) phase using FAC-Scan flow cytometric analysis. It was further shown that cGMP, p42/p44 mitogen-activated protein kinase, or AKT kinase-mediated signaling pathways did not contribute to the YC-1-induced effect. Of note, YC-1 induced a dramatic increase in the expression of cyclin-dependent kinase (CDK)-inhibitory protein, p21(CIP1/WAP1), and a modest increase in p27(KIP1). The association of p21(CIP1/WAP1) with CDK2 was markedly increased in cells responsive to YC-1. YC-1 did not modify the expression of cyclin D1, cyclin E, CDK2, or CDK4. In a corollary in vivo study, YC-1 induced dose-dependent inhibition of tumor growth in mice inoculated with HA22T cells. Immunohistochemical analysis revealed an inverse relationship between the staining of p21(CIP1/WAF) and the staining of Ki-67, a cell proliferation marker. Based on the results reported herein, we suggest that YC-1 induces cell cycle arrest and inhibits tumor growth both in vitro and in vivo via the up-regulation of p21(CIP1/WAP1) expression in HA22T cells. Because of this, YC-1 is a potential antitumor agent worthy of further investigation.
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Affiliation(s)
- Shih-Wei Wang
- Pharmacological Institutes, College of Medicine, National Taiwan University, 1 Jen-Ai Road, Sect. 1, Taipei, Taiwan
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903
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Li LC, Okino ST, Dahiya R. DNA methylation in prostate cancer. Biochim Biophys Acta Rev Cancer 2004; 1704:87-102. [PMID: 15363862 DOI: 10.1016/j.bbcan.2004.06.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 06/16/2004] [Accepted: 06/16/2004] [Indexed: 12/31/2022]
Abstract
Prostate cancer is the most common malignancy and the second leading cause of cancer death among men in the United States. There are three well-established risk factors for prostate cancer: age, race and family history. The molecular bases for these risk factors are unclear; however, they may be influenced by epigenetic events. Epigenetic events covalently modify chromatin and alter gene expression. Methylation of cytosine residues within CpG islands on gene promoters is a primary epigenetic event that acts to suppress gene expression. In tumorigenesis, the normal functioning of the epigenetic-regulatory system is disrupted leading to inappropriate CpG island hypermethylation and aberrant expression of a battery of genes involved in critical cellular processes. Cancer-dependent epigenetic regulation of genes involved in DNA damage repair, hormone response, cell cycle control and tumor-cell adhesion/metastasis can contribute significantly to tumor initiation, progression and metastasis and, thereby, increase prostate cancer susceptibility and risk. In this review, we will discuss current research on genes that are hypermethylated in human prostate cancer. We will also discuss the potential involvement of DNA methylation in age-related, race-related and hereditary prostate cancer, and the potential use of hypermethylated genes as biomarkers to detect prostate cancer and assess its risk.
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Affiliation(s)
- Long-Cheng Li
- Department of Urology, Veterans Affairs Medical Center, and University of California San Francisco, 4150 Clement Street, San Francisco, CA 94121, USA
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904
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Bai M, Tsanou E, Agnantis NJ, Kamina S, Grepi C, Stefanaki K, Rontogianni D, Galani V, Kanavaros P. Proliferation profile of classical Hodgkin's lymphomas. Increased expression of the protein cyclin D2 in Hodgkin's and Reed-Sternberg cells. Mod Pathol 2004; 17:1338-45. [PMID: 15354186 DOI: 10.1038/modpathol.3800183] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There is accumulating evidence that Hodgkin's and Reed-Sternberg cells of classical Hodgkin's lymphomas (cHL) display multiple and concurrent alterations in different pathways and checkpoints of the cell cycle. However, the expression of cyclin D2 and its relation to other major cell cycle proteins has not been analyzed in cHL. The aim of the present study was to assess expression of cyclin D2, Ki67, cyclin A, cyclin B1, cyclin D1, cyclin D3, cyclin E, p53, Rb, p16 and p27 proteins in order to gain further insight into the proliferation profile of cHL. Overexpression of cyclin D2 in Hodgkin's and Reed-Sternberg cells was detected in 64/89 (72%) cases of cHL. This finding, in view of recent in vitro data showing that constitutive activation of nuclear factor (NF)-kB could upregulate cyclin D2 expression in part via signal transducer and activator of transcription (STAT)-5a, suggests that induction of cyclin D2 expression may support the proliferation of Hodgkin's and Reed-Sternberg cells. In addition, the present study showed that (1) increased p27 expression status was significantly correlated with higher levels of cyclin A expression (P=0.048) and (2) increased p53 expression status was significantly correlated with higher levels of cyclin A (P<0.001) and cyclin B1 (P=0.040) expression. The association between increased p27 and p53 expression status and higher expression levels of G2/M cyclins suggests that the impairment of the growth inhibitory activity of the p27 and p53 tumor suppressor pathways may promote the proliferation of Hodgkin's and Reed-Sternberg cells.
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Affiliation(s)
- Maria Bai
- Department of Pathology, Medical Faculty, University of Ioannina, 45110 Ioannina, Greece.
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905
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Matheu A, Pantoja C, Efeyan A, Criado LM, Martín-Caballero J, Flores JM, Klatt P, Serrano M. Increased gene dosage of Ink4a/Arf results in cancer resistance and normal aging. Genes Dev 2004; 18:2736-46. [PMID: 15520276 PMCID: PMC528894 DOI: 10.1101/gad.310304] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mammalian genes frequently present allelic variants that differ in their expression levels and that, in the case of tumor suppressor genes, can be of relevance for cancer susceptibility and aging. We report here the characterization of a novel mouse model with increased activity for the Ink4a and Arf tumor suppressors. We have generated a "super Ink4a/Arf" mouse strain carrying a transgenic copy of the entire Ink4a/Arf locus. Cells derived from super Ink4a/Arf mice have increased resistance to in vitro immortalization and oncogenic transformation. Importantly, super Ink4a/Arf mice manifest higher resistance to cancer compared to normal, nontransgenic, mice. Finally, super Ink4a/Arf mice have normal aging and lifespan. Together, these results indicate that modest increases in the activity of the Ink4a/Arf tumor suppressor result in a beneficial cancer-resistant phenotype without affecting normal viability or aging.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/toxicity
- Animals
- Carcinogens/toxicity
- Cell Survival
- Cell Transformation, Neoplastic/genetics
- Cells, Cultured
- Cellular Senescence
- Cyclin-Dependent Kinase Inhibitor p16/genetics
- Cyclin-Dependent Kinase Inhibitor p16/physiology
- Embryo, Mammalian/cytology
- Embryo, Mammalian/physiology
- Female
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Gene Dosage
- Genes, Tumor Suppressor
- Heterozygote
- Homozygote
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neoplasms, Experimental/chemically induced
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/prevention & control
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Affiliation(s)
- Ander Matheu
- Spanish National Cancer Center (CNIO), Madrid E-28029, Spain
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906
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Specific inhibition of cyclin-dependent kinase 4/6 by PD 0332991 and associated antitumor activity in human tumor xenografts. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.1427.3.11] [Citation(s) in RCA: 398] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
PD 0332991 is a highly specific inhibitor of cyclin-dependent kinase 4 (Cdk4) (IC50, 0.011 μmol/L) and Cdk6 (IC50, 0.016 μmol/L), having no activity against a panel of 36 additional protein kinases. It is a potent antiproliferative agent against retinoblastoma (Rb)-positive tumor cells in vitro, inducing an exclusive G1 arrest, with a concomitant reduction of phospho-Ser780/Ser795 on the Rb protein. Oral administration of PD 0332991 to mice bearing the Colo-205 human colon carcinoma produces marked tumor regression. Therapeutic doses of PD 0332991 cause elimination of phospho-Rb and the proliferative marker Ki-67 in tumor tissue and down-regulation of genes under the transcriptional control of E2F. The results indicate that inhibition of Cdk4/6 alone is sufficient to cause tumor regression and a net reduction in tumor burden in some tumors.
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907
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Nelsen CJ, Kuriyama R, Hirsch B, Negron VC, Lingle WL, Goggin MM, Stanley MW, Albrecht JH. Short term cyclin D1 overexpression induces centrosome amplification, mitotic spindle abnormalities, and aneuploidy. J Biol Chem 2004; 280:768-76. [PMID: 15509582 DOI: 10.1074/jbc.m407105200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In normal cells, cyclin D1 is induced by growth factors and promotes progression through the G(1) phase of the cell cycle. Cyclin D1 is also an oncogene that is thought to act primarily by bypassing the requirement for mitogens during the G(1) phase. Studies of clinical tumors have found that cyclin D1 overexpression is associated with chromosome abnormalities, although a causal effect has not been established in experimental systems. In this study, we found that transient expression of cyclin D1 in normal hepatocytes in vivo triggered dysplastic mitoses, accumulation of supernumerary centrosomes, abnormalities of the mitotic spindle, and marked chromosome changes within several days. This was associated with up-regulation of checkpoint genes p53 and p21 as well as hepatocyte apoptosis in the liver. Transient transfection of cyclin D1 also induced centrosome and mitotic spindle abnormalities in breast epithelial cells, suggesting that this may be a generalized effect. These results indicate that cyclin D1 can induce deregulation of the mitotic apparatus and aneuploidy, effects that could contribute to the role of this oncogene in malignancy.
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Affiliation(s)
- Christopher J Nelsen
- Division of Gastroenterology, Hennepin County Medical Center, Minneapolis, Minnesota 55415, USA
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908
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Chan KS, Sano S, Kiguchi K, Anders J, Komazawa N, Takeda J, DiGiovanni J. Disruption of Stat3 reveals a critical role in both the initiation and the promotion stages of epithelial carcinogenesis. J Clin Invest 2004; 114:720-8. [PMID: 15343391 PMCID: PMC514583 DOI: 10.1172/jci21032] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Accepted: 06/29/2004] [Indexed: 01/07/2023] Open
Abstract
Constitutive activation of signal transducer and activator of transcription 3 (Stat3) has been found in a wide spectrum of human malignancies. Here, we have assessed the effect of Stat3 deficiency on skin tumor development using the 2-stage chemical carcinogenesis model. The epidermis of Stat3-deficient mice showed a significantly reduced proliferative response following treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) because of a defect in G1-to-S-phase cell cycle progression. Treatment with the tumor initiator 7,12-dimethylbenz[a]anthracene (DMBA) resulted in a significant increase in the number of keratinocyte stem cells undergoing apoptosis in the bulge region of hair follicles of Stat3-deficient mice compared with nontransgenic littermates. Notably, Stat3-deficient mice were completely resistant to skin tumor development when DMBA was used as the initiator and TPA as the promoter. Abrogation of Stat3 function using a decoy oligonucleotide inhibited the growth of initiated keratinocytes possessing an activated Ha-ras gene, both in vitro and in vivo. In addition, injection of Stat3 decoy into skin tumors inhibited their growth. To our knowledge, these data provide the first evidence that Stat3 is required for de novo epithelial carcinogenesis, through maintaining the survival of DNA-damaged stem cells and through mediating and maintaining the proliferation necessary for clonal expansion of initiated cells during tumor promotion. Collectively, these data suggest that, in addition to its emerging role as a target for cancer therapy, Stat3 may also be a target for cancer prevention strategies.
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Affiliation(s)
- Keith Syson Chan
- Department of Carcinogenesis, The University of Texas M.D. Anderson Cancer Center, Smithville, Texas, USA
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909
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Abstract
The processes by which cancer cells leave the tumor and enter adjacent tissue is known as invasion, whereas metastasis refers to secondary tumor colonization of tissue at a distance from the primary lesion. These two events are the most lethal of cancer phenomena and the signaling mechanisms that govern them are complex. The Ras signaling pathways are well represented in their involvement in tumor initiation, but considerably less is known about their contribution to invasion and metastasis. In this review, we discuss the current evidence for mutant Ras proteins as significant players in these aspects of cancer progression.
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Affiliation(s)
- Paul M Campbell
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, CB# 7295, Chapel Hill, NC 27599-7295, USA.
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910
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Malumbres M, Sotillo R, Santamaría D, Galán J, Cerezo A, Ortega S, Dubus P, Barbacid M. Mammalian cells cycle without the D-type cyclin-dependent kinases Cdk4 and Cdk6. Cell 2004; 118:493-504. [PMID: 15315761 DOI: 10.1016/j.cell.2004.08.002] [Citation(s) in RCA: 587] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2004] [Revised: 06/21/2004] [Accepted: 06/28/2004] [Indexed: 01/08/2023]
Abstract
Cdk4 and Cdk6 are thought to be essential for initiation of the cell cycle in response to mitogenic stimuli. Previous studies have shown that Cdk4 is dispensable for proliferation in most cell types, an observation attributed to a putative compensatory role by Cdk6. Cdk6-null mice are viable and develop normally although hematopoiesis is slightly impaired. Embryos defective for Cdk4 and Cdk6 die during the late stages of embryonic development due to severe anemia. However, these embryos display normal organogenesis and most cell types proliferate normally. In vitro, embryonic fibroblasts lacking Cdk4 and Cdk6 proliferate and become immortal upon serial passage. Moreover, quiescent Cdk4/Cdk6-null cells respond to serum stimulation and enter S phase with normal kinetics although with lower efficiency. These results indicate that D-type cyclin-dependent kinases are not essential for cell cycle entry and suggest the existence of alternative mechanisms to initiate cell proliferation upon mitogenic stimulation.
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Affiliation(s)
- Marcos Malumbres
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), E-28029 Madrid, Spain.
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911
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Abstract
The revolution in cancer research can be summed up in a single sentence: cancer is, in essence, a genetic disease. In the last decade, many important genes responsible for the genesis of various cancers have been discovered, their mutations precisely identified, and the pathways through which they act characterized. The purposes of this review are to highlight examples of progress in these areas, indicate where knowledge is scarce and point out fertile grounds for future investigation.
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Affiliation(s)
- Bert Vogelstein
- Howard Hughes Medical Institute and The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University Medical Institutions, Baltimore, Maryland 21231, USA.
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912
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Jack A, Barrans S. Recent advances in the understanding of aggressive B-cell lymphomas. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.cdip.2004.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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913
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Iwasaki M, Kuwata T, Yamazaki Y, Jenkins NA, Copeland NG, Osato M, Ito Y, Kroon E, Sauvageau G, Nakamura T. Identification of cooperative genes for NUP98-HOXA9 in myeloid leukemogenesis using a mouse model. Blood 2004; 105:784-93. [PMID: 15454493 DOI: 10.1182/blood-2004-04-1508] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The chromosomal translocation t(7; 11)(p15;p15), observed in human myeloid leukemia, results in a NUP98 and HOXA9 gene fusion. We generated a transgenic mouse line that specifically expressed the chimeric NUP98-HOXA9 gene in the myeloid lineage. While only 20% of the transgenic mice progressed to leukemia after a latency period, myeloid progenitor cells from nonleukemic transgenic mice still exhibited increased proliferative potential. This suggested that the NUP98-HOXA9 fusion induced a preleukemic phase, and other factors were required for complete leukemogenesis. NUP98-HOXA9 expression promoted the onset of retrovirus-induced BXH2 myeloid leukemia. This phenomenon was used to identify cooperative disease genes as common integration sites (CISs). Meis1, a known HOX cofactor, was identified as a CIS with a higher integration frequency in transgenic than in wild-type BXH2 mice. By the same means we identified further 4 candidate cooperative genes, Dnalc4, Fcgr2b, Fcrl, and Con1. These genes cooperated with NUP98-HOXA9 in transforming NIH 3T3 cells. The system described here is a powerful tool to identify cooperative oncogenes and will assist in the clarification of the multistep process of carcinogenesis.
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Affiliation(s)
- Masayuki Iwasaki
- Department of Carcinogenesis, Japanese Foundation for Cancer Research, Tokyo, Japan
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914
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915
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Bocchetta M, Carbone M. Epidemiology and molecular pathology at crossroads to establish causation: molecular mechanisms of malignant transformation. Oncogene 2004; 23:6484-91. [PMID: 15322519 DOI: 10.1038/sj.onc.1207855] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epidemiology is a very reliable science for the identification of carcinogens. Epidemiological studies require that the effect, cancer in this case, has already occurred, when of course it would be more desirable to identify potential carcinogenic substances at an earlier stage before they have caused a large number of malignancies and thus become identifiable by epidemiological studies. In the past 30 years, molecular pathology (which includes chemistry, biochemistry, molecular biology, molecular virology, molecular genetics, epigenetics, genomics, proteomics, and other molecular-based approaches) has identified some key alterations that are required for cellular transformation and malignancy. Agents that specifically interfere with some of these mechanisms are suspected human carcinogens. It can be stated that tumor formation requires the following steps: (1) inactivation of Rb and p53 cellular pathways; (2) activation of Ras and/or other growth promoting pathways; (3) inactivation of phosphatase 2A that causes changes in the phosphorylation and activity of several cellular proteins; (4) evasion of apoptosis; (5) telomerase activation or alternative mechanisms of cellular immortalization; (6) angiogenic activity; and (7) the ability to invade surrounding tissues and to metastasize. Here, we review the molecular mechanisms of cellular transformation. The integration of this knowledge with classical epidemiology and animal studies should permit a more rapid and accurate identification of human carcinogens.
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Affiliation(s)
- Maurizio Bocchetta
- Cardinal Bernardin Cancer Center, Loyola University Chicago, 2160 South First Ave, Maywood, IL 60153, USA.
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916
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Goggin MM, Nelsen CJ, Kimball SR, Jefferson LS, Morley SJ, Albrecht JH. Rapamycin-sensitive induction of eukaryotic initiation factor 4F in regenerating mouse liver. Hepatology 2004; 40:537-44. [PMID: 15349891 DOI: 10.1002/hep.20338] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Following acute injuries that diminish functional liver mass, the remaining hepatocytes substantially increase overall protein synthesis to meet increased metabolic demands and to allow for compensatory liver growth. Previous studies have not clearly defined the mechanisms that promote protein synthesis in the regenerating liver. In the current study, we examined the regulation of key proteins involved in translation initiation following 70% partial hepatectomy (PH) in mice. PH promoted the assembly of eukaryotic initiation factor (eIF) 4F complexes consisting of eIF4E, eIF4G, eIF4A1, and poly-A binding protein. eIF4F complex formation after PH occurred without detectable changes in eIF4E-binding protein 1 (4E-BP1) phosphorylation or its binding eIF4E. The amount of serine 1108-phosphorylated eIF4G (but not Ser209-phosphorylated eIF4E) was induced following PH. These effects were antagonized by treatment with rapamycin, indicating that target of rapamycin (TOR) activity is required for eIF4F assembly in the regenerating liver. Rapamycin inhibited the induction of cyclin D1, a known eIF4F-sensitive gene, at the level of protein expression but not messenger RNA (mRNA) expression. In conclusion, increased translation initiation mediated by the mRNA cap-binding complex eIF4F contributes to the induction of protein synthesis during compensatory liver growth. Further study of factors that regulate translation initiation may provide insight into mechanisms that govern metabolic homeostasis and regeneration in response to liver injury.
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Affiliation(s)
- Melissa M Goggin
- Division of Gastroenterology, Hennepin County Medical Center, Minneapolis, MN 55415, USA
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917
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Abstract
The cytoplasmic serine/threonine kinase BRAF and receptor tyrosine kinases of the platelet-derived growth factor receptor (PDGFR) family are frequently activated in cancer by mutations of an equivalent amino acid. Structural studies have provided important insights into why these very different kinases share similar oncogenic hot spots and why the PDGFR juxtamembrane region is also a frequent oncogenic target. This research has implications for other kinases that are mutated in human tumours and for the treatment of cancer using kinase inhibitors.
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Affiliation(s)
- Nick J Dibb
- Institute of Reproductive and Developmental Biology, Imperial College, Hammersmith Campus, London W12 ONN, UK.
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918
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Chan KS, Sano S, Kiguchi K, Anders J, Komazawa N, Takeda J, DiGiovanni J. Disruption of Stat3 reveals a critical role in both the initiation and the promotion stages of epithelial carcinogenesis. J Clin Invest 2004. [DOI: 10.1172/jci200421032] [Citation(s) in RCA: 273] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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919
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Eisenbrand G, Hippe F, Jakobs S, Muehlbeyer S. Molecular mechanisms of indirubin and its derivatives: novel anticancer molecules with their origin in traditional Chinese phytomedicine. J Cancer Res Clin Oncol 2004; 130:627-35. [PMID: 15340840 DOI: 10.1007/s00432-004-0579-2] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Accepted: 04/05/2004] [Indexed: 10/26/2022]
Abstract
Indirubin, a 3, 2' bisindole isomer of indigo, has originally been identified as the active principle of a traditional Chinese preparation and has been proven to exhibit antileukemic effectiveness in chronic myelocytic leukemia. Indirubin was detected to represent a novel lead structure with potent inhibitory potential towards cyclin-dependent kinases (CDKs) resulting from high affinity binding into the enzymes ATP binding site. This seminal finding triggered our research to improve the pharmacological activities of the parent molecule within comprehensive structure-activity studies. Molecular modifications made novel anticancer compounds accessible with strongly improved CDK inhibitory potential and with broad spectrum antitumour activity. This novel family of compounds holds strong promise for clinical anticancer activity and might be useful also in several important noncancer indications, including Alzheimer's disease or diabetes.
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Affiliation(s)
- Gerhard Eisenbrand
- Division of Food Chemistry and Environmental Toxicology, Department of Chemistry, University of Kaiserslautern, P.O. Box 3049, 67663, Kaiserslautern, Germany.
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920
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Mitra J, Enders GH. Cyclin A/Cdk2 complexes regulate activation of Cdk1 and Cdc25 phosphatases in human cells. Oncogene 2004; 23:3361-7. [PMID: 14767478 PMCID: PMC1924680 DOI: 10.1038/sj.onc.1207446] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mitotic entry, a critical decision point for maintaining genetic stability, is governed by the cyclin B/Cyclin dependent kinase 1 (Cdc2) complex. In Xenopus oocytes and early embryos, accumulation of cyclin B activates Cdk1, which then phosphorylates and activates the positive regulator Cdc25 in an autocatalytic feedback loop. However, cyclin B levels do not increase as some human cells approach mitosis, and the key factors regulating Cdk1 activation in human cells are unknown. We report here that reducing cyclin A expression by RNA interference (RNAi) in primary human fibroblasts inhibited activation of Cdc25B and Cdc25C and dephosphorylation of Cdk1 on tyrosine (tyr) 15. These results were reproduced in U2-OS cells by inducing the expression of a dominant-negative (dn) mutant of Cdk2, the principal cyclin A binding partner. Cdk2-dn induction could inhibit Cdc25B activity and foster Cdk1 tyr phosphorylation within the S phase, temporally dissociating these events from Cdk1 activation at mitosis. In contrast, reducing Cdk1 expression delayed mitotic entry without markedly impairing Cdc25B or Cdc25C activity. These results suggest that cyclin A/Cdk2 complexes are key regulators of Cdc25 and Cdk1 activation in human cells. This pathway appears to be commonly deregulated in cancer.
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Affiliation(s)
- Jayashree Mitra
- Departments of Medicine and Genetics and Cancer Center, University of Pennsylvania, Philadelphia, PA 19104-6140, USA.
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921
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922
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Zhu H, Zhang L, Wu S, Teraishi F, Davis JJ, Jacob D, Fang B. Induction of S-phase arrest and p21 overexpression by a small molecule 2[[3-(2,3-dichlorophenoxy)propyl] amino]ethanol in correlation with activation of ERK. Oncogene 2004; 23:4984-92. [PMID: 15122344 DOI: 10.1038/sj.onc.1207645] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We recently found that a small molecule 2[[3-(2,3-dichlorophenoxy)propyl]amino]ethanol (2,3-DCPE) could induce apoptosis and downregulate Bcl-XL expression in various cancer cells. Here, we found that 2,3-DCPE suppressed the proliferation of Bcl-XL-overexpressing cancer cells without inducing apoptosis. Subsequently, we found that 2,3-DCPE could induce S-phase arrest and upregulate p21 but not p27 at a time- and dose-dependent but p53-dispensable manner in DLD-1 human colon cancer cells. Activation of ERK was also detected after treatment with 2,3-DCPE. Moreover, p21 induction was dramatically attenuated by ERK inhibitors PD98059 and U0126. Induction of p21 and S-phase arrest and corresponding activation of ERK were also observed in ATM-defective cells, suggesting that 2,3-DCPE-induced these events were ATM-dispensable. Furthermore, ERK inhibitors dramatically attenuated 2,3-DCPE-induced S-phase arrest. Together, our data indicate that ERK activation correlated with the 2,3-DCPE-mediated induction of p21 expression and S-phase arrest. This finding may have implication for cancer therapy.
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Affiliation(s)
- Hongbo Zhu
- Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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923
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Chen W, Lee J, Cho SY, Fine HA. Proteasome-Mediated Destruction of the Cyclin A/Cyclin-Dependent Kinase 2 Complex Suppresses Tumor Cell Growth in Vitro and in Vivo. Cancer Res 2004; 64:3949-57. [PMID: 15173007 DOI: 10.1158/0008-5472.can-03-3906] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cyclin-dependent kinases (cdks) represent potentially promising molecular targets for cancer therapeutic strategies. To evaluate the antitumor activity of selective cyclin/cdk inhibition, we constructed a chimeric protein composed of a F-box protein (TrCP) fused to a peptide comprising the cyclin/cdk2 binding motif in p21-like cdk inhibitors (TrCP-LFG). We now demonstrate that endogenous cyclin A and its binding substrate, cdk2, can be tethered to beta-TrCP, ubiquitinated, and effectively degraded. Degradation of cdk2 and cyclin A together, but not cdk2 alone, results in massive tumor cell apoptosis in vitro and in vivo in a proteasome-dependent manner with no toxicity to normal tissue. These data demonstrate that cyclin A and/or the cyclin A/cdk2 complex is a promising anticancer target with a high therapeutic index.
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Affiliation(s)
- Wei Chen
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Neurological Disorder and Stroke, NIH, Bethesda, Maryland 20892, USA
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924
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Pevarello P, Brasca MG, Amici R, Orsini P, Traquandi G, Corti L, Piutti C, Sansonna P, Villa M, Pierce BS, Pulici M, Giordano P, Martina K, Fritzen EL, Nugent RA, Casale E, Cameron A, Ciomei M, Roletto F, Isacchi A, Fogliatto G, Pesenti E, Pastori W, Marsiglio A, Leach KL, Clare PM, Fiorentini F, Varasi M, Vulpetti A, Warpehoski MA. 3-Aminopyrazole Inhibitors of CDK2/Cyclin A as Antitumor Agents. 1. Lead Finding. J Med Chem 2004; 47:3367-80. [PMID: 15189033 DOI: 10.1021/jm031145u] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abnormal proliferation mediated by disruption of the normal cell cycle mechanisms is a hallmark of virtually all cancer cells. Compounds targeting complexes between cyclin-dependent kinases (CDK) and cyclins, such as CDK2/cyclin A and CDK2/cyclin E, and inhibiting their kinase activity are regarded as promising antitumor agents to complement the existing therapies. From a high-throughput screening effort, we identified a new class of CDK2/cyclin A/E inhibitors. The hit-to-lead expansion of this class is described. X-ray crystallographic data of early compounds in this series, as well as in vitro testing funneled for rapidly achieving in vivo efficacy, led to a nanomolar inhibitor of CDK2/cyclin A (N-(5-cyclopropyl-1H-pyrazol-3-yl)-2-(2-naphthyl)acetamide (41), PNU-292137, IC50 = 37 nM) with in vivo antitumor activity (TGI > 50%) in a mouse xenograft model at a dose devoid of toxic effects.
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Affiliation(s)
- Paolo Pevarello
- Chemistry Department, Pharmacia Italia, Viale Pasteur 10, 20014 Nerviano (MI), Italy.
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925
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Brezak MC, Quaranta M, Mondésert O, Galcera MO, Lavergne O, Alby F, Cazales M, Baldin V, Thurieau C, Harnett J, Lanco C, Kasprzyk PG, Prevost GP, Ducommun B. A Novel Synthetic Inhibitor of CDC25 Phosphatases. Cancer Res 2004; 64:3320-5. [PMID: 15126376 DOI: 10.1158/0008-5472.can-03-3984] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
CDC25 dual-specificity phosphatases are essential regulators that dephosphorylate and activate cyclin-dependent kinase/cyclin complexes at key transitions of the cell cycle. CDC25 activity is currently considered to be an interesting target for the development of new antiproliferative agents. Here we report the identification of a new CDC25 inhibitor and the characterization of its effects at the molecular and cellular levels, and in animal models. BN82002 inhibits the phosphatase activity of recombinant human CDC25A, B, and C in vitro. It impairs the proliferation of tumoral cell lines and increases cyclin-dependent kinase 1 inhibitory tyrosine phosphorylation. In synchronized HeLa cells, BN82002 delays cell cycle progression at G1-S, in S phase and at the G2-M transition. In contrast, BN82002 arrests U2OS cell cycle mostly in the G1 phase. Selectivity of this inhibitor is demonstrated: (a) by the reversion of the mitotic-inducing effect observed in HeLa cells upon CDC25B overexpression; and (b) by the partial reversion of cell cycle arrest in U2OS expressing CDC25. We also show that BN82002 reduces growth rate of human tumor xenografts in athymic nude mice. BN82002 is a original CDC25 inhibitor that is active both in cell and animal models. This greatly reinforces the interest in CDC25 as an anticancer target.
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926
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Kenny LM, Aboagye EO, Price PM. Positron Emission Tomography Imaging of Cell Proliferation in Oncology. Clin Oncol (R Coll Radiol) 2004; 16:176-85. [PMID: 15191004 DOI: 10.1016/j.clon.2003.10.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Tumour-cell proliferation is a hallmark of the malignant phenotype. Positron emission tomography (PET) offers a unique method of imaging biological and biochemical changes in vivo. Radiolabelled thymidine and thymidine analogues are currently in development as PET tracers. By studying the uptake and kinetics of such compounds using PET, a measure of DNA synthesis and hence cell proliferation can be obtained. Molecular imaging of cellular proliferation with PET is now possible, and has the potential to play an important role in the evaluation of efficacy of new anti-cancer agents.
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Affiliation(s)
- L M Kenny
- Molecular Therapy Group and PET Oncology Group, Hammersmith Hospital, London, UK
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927
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Pruneri G, Mazzarol G, Fabris S, Del Curto B, Bertolini F, Neri A, Viale G. Cyclin D3 immunoreactivity in gastrointestinal stromal tumors is independent of cyclin D3 gene amplification and is associated with nuclear p27 accumulation. Mod Pathol 2004; 16:886-92. [PMID: 13679452 DOI: 10.1097/01.mp.0000085026.38856.b9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An abnormal expression of cyclin D3, a key regulator of the cell cycle, has been documented in a variety of human malignancies, and the cyclin D3 gene, mapping to 6p21, may be deregulated in human tumors as a result of the t(6;14)(p21.1;q32.3) translocation or gene amplification. In the current study, we for the first time investigated by immunohistochemistry and fluorescence in situ hybridization (FISH) the prevalence of cyclin D3 abnormalities in gastrointestinal stromal tumors (GISTs), comparing the results with traditional pathological characteristics, p27 immunoreactivity (IR), and Ki-67 labeling index (LI). All the tumors showed nuclear cyclin D3 IR, with a percentage of immunostained neoplastic cells ranging from 10 to 95% (mean, 67.3 +/- 22.9%). In 4 (40%) of the 10 cases analyzed by FISH, cyclin D3 extrasignals were detected. Cohybridization with probes specific for the centromeric region and the long arm of chromosome 6 indicated trisomy in one case, whereas in the remaining three cases the pattern was highly suggestive for the occurrence of an isochromosome 6p. There was no association between the cyclin D3 gene copy number and IR for the encoded protein. Cyclin D3 IR was positively associated with p27 IR (P =.004) but not with Ki-67 LI or tumor malignant potential. On the contrary, p27 IR was inversely associated with Ki-67 LI (P =.004) and was more prevalent in tumors of low or intermediate malignant potential, though at a borderline level of statistical significance (P =.066) only. These data suggest that cyclin D3 expression in GISTs is independent of gene amplification and that this protein may be involved in the pathogenesis of GISTs by counteracting the inhibitory activities of p27.
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928
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Hideshima T, Bergsagel PL, Kuehl WM, Anderson KC. Advances in biology of multiple myeloma: clinical applications. Blood 2004; 104:607-18. [PMID: 15090448 DOI: 10.1182/blood-2004-01-0037] [Citation(s) in RCA: 465] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
There appear to be 2 pathways involved in the early pathogenesis of premalignant monoclonal gammopathy of undetermined significance (MGUS) and malignant multiple myeloma (MM) tumors. Nearly half of these tumors are nonhyperdiploid and mostly have immunoglobulin H (IgH) translocations that involve 5 recurrent chromosomal loci, including 11q13 (cyclin D1), 6p21 (cyclin D3), 4p16 (fibroblast growth factor receptor 3 [FGFR3] and multiple myeloma SET domain [MMSET]), 16q23 (c-maf), and 20q11 (mafB). The remaining tumors are hyperdiploid and contain multiple trisomies involving chromosomes 3, 5, 7, 9, 11, 15, 19, and 21, but infrequently have IgH translocations involving the 5 recurrent loci. Dysregulated expression of cyclin D1, D2, or D3 appears to occur as an early event in virtually all of these tumors. This may render the cells more susceptible to proliferative stimuli, resulting in selective expansion as a result of interaction with bone marrow stromal cells that produce interleukin-6 (IL-6) and other cytokines. There are 5 proposed tumor groups, defined by IgH translocations and/or cyclin D expression, that appear to have differences in biologic properties, including interaction with stromal cells, prognosis, and response to specific therapies. Delineation of the mechanisms mediating MM cell proliferation, survival, and migration in the bone marrow (BM) microenvironment may both enhance understanding of pathogenesis and provide the framework for identification and validation of novel molecular targets.
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Affiliation(s)
- Teru Hideshima
- Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
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929
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Sachs Z, Sharpless NE, DePinho RA, Rosenberg N. p16(Ink4a) interferes with Abelson virus transformation by enhancing apoptosis. J Virol 2004; 78:3304-11. [PMID: 15016851 PMCID: PMC371071 DOI: 10.1128/jvi.78.7.3304-3311.2004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pre-B-cell transformation by Abelson virus (Ab-MLV) is a multistep process in which primary transformants are stimulated to proliferate but subsequently undergo crisis, a period of erratic growth marked by high levels of apoptosis. Inactivation of the p53 tumor suppressor pathway is an important step in this process and can be accomplished by mutation of p53 or down-modulation of p19(Arf), a p53 regulatory protein. Consistent with these data, pre-B cells from either p53 or Ink4a/Arf null mice bypass crisis. However, the Ink4a/Arf locus encodes both p19(Arf) and a second tumor suppressor, p16(Ink4a), that blocks cell cycle progression by inhibiting Cdk4/6. To determine if p16(Ink4a) plays a role in Ab-MLV transformation, primary transformants derived from Arf(-/-) and p16(Ink4a(-/-)) mice were compared. A fraction of those derived from Arf(-/-) animals underwent crisis, and even though all p16(Ink4a(-/-)) primary transformants experienced crisis, these cells became established more readily than cells derived from +/+ mice. Analyses of Ink4a/Arf(-/-) cells infected with a virus that expresses both v-Abl and p16(Ink4a) revealed that p16(Ink4a) expression does not alter cell cycle profiles but does increase the level of apoptosis in primary transformants. These results indicate that both products of the Ink4a/Arf locus influence Ab-MLV transformation and reveal that in addition to its well-recognized effects on the cell cycle, p16(Ink4a) can suppress transformation by inducing apoptosis.
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Affiliation(s)
- Zohar Sachs
- Department of Pathology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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930
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Polychronopoulos P, Magiatis P, Skaltsounis AL, Myrianthopoulos V, Mikros E, Tarricone A, Musacchio A, Roe SM, Pearl L, Leost M, Greengard P, Meijer L. Structural basis for the synthesis of indirubins as potent and selective inhibitors of glycogen synthase kinase-3 and cyclin-dependent kinases. J Med Chem 2004; 47:935-46. [PMID: 14761195 DOI: 10.1021/jm031016d] [Citation(s) in RCA: 281] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pharmacological inhibitors of glycogen synthase kinase-3 (GSK-3) and cyclin-dependent kinases have a promising potential for applications against several neurodegenerative diseases such as Alzheimer's disease. Indirubins, a family of bis-indoles isolated from various natural sources, are potent inhibitors of several kinases, including GSK-3. Using the cocrystal structures of various indirubins with GSK-3beta, CDK2 and CDK5/p25, we have modeled the binding of indirubins within the ATP-binding pocket of these kinases. This modeling approach provided some insight into the molecular basis of indirubins' action and selectivity and allowed us to forecast some improvements of this family of bis-indoles as kinase inhibitors. Predicted molecules, including 6-substituted and 5,6-disubstituted indirubins, were synthesized and evaluated as CDK and GSK-3 inhibitors. Control, kinase-inactive indirubins were obtained by introduction of a methyl substitution on N1.
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Affiliation(s)
- Panagiotis Polychronopoulos
- Laboratory of Pharmacognosy and Laboratory of Pharmaceutical Chemistry, Department of Pharmacy, University of Athens, Panepistimiopolis Zografou, GR-15771 Athens, Greece
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931
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Gompel M, Leost M, De Kier Joffe EB, Puricelli L, Franco LH, Palermo J, Meijer L. Meridianins, a new family of protein kinase inhibitors isolated from the Ascidian Aplidium meridianum. Bioorg Med Chem Lett 2004; 14:1703-7. [PMID: 15026054 DOI: 10.1016/j.bmcl.2004.01.050] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2003] [Revised: 01/20/2004] [Accepted: 01/20/2004] [Indexed: 11/25/2022]
Abstract
Meridianins are brominated 3-(2-aminopyrimidine)-indoles which are purified from Aplidium meridianum, an Ascidian from the South Atlantic (South Georgia Islands). We here show that meridianins inhibit various protein kinases such as cyclin-dependent kinases, glycogen synthase kinase-3, cyclic nucleotide-dependent kinases and casein kinase 1. Meridianins prevent cell proliferation and induce apoptosis, a demonstration of their ability to enter cells and to interfere with the activity of kinases important for cell division and cell death. These results suggest that meridianins constitute a promising scaffold from which more potent and selective protein kinase inhibitors could be designed.
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Affiliation(s)
- Marie Gompel
- C.N.R.S., Cell Cycle Group, Station Biologique, B.P. 74, 29682 Roscoff cedex, Bretagne, France
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932
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Wang XY, Shen SR, Liu HY, Zhang XM, Peng C, Huang H, Liu F, Li XL, Li GY. Effects of tumor suppressor gene NGX6 on growth of human colon cancer cell line HT-29. Shijie Huaren Xiaohua Zazhi 2004; 12:574-579. [DOI: 10.11569/wcjd.v12.i3.574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: NGX6 is a novel tumor suppressor gene candidate, and the expression of NGX6 decreased in colon cancer specimen, which suggested that the down-regulation of NGX6 was closely related to tumorigenesis of colon cancer. This study was designed to explore effects of NGX6 on the cytobiological characteristics of human colon cancer cell line HT-29 and to elucidate the role of NGX6 in the colon cancer.
METHODS: The mammal expression vector of pcDNA3.1(+)/NGX6 was transfected into human colon cancer cell line HT-29 cells by liposome.The integration of the exogenous vector DNA and the expression of NGX6 were detected by dot blot and RT-PCR. Finally, the cytobiological characteristics of positive clone were analyzed by growth curves of cells, MTT, soft agar assay, FCM and xenograft.
RESULTS: pcDNA3.1(+)/NGX6/HT-29 cells grew slower than pcDNA3.1(+)/HT-29 and HT-29 cells (P < 0.05), and the PDT of pcDNA3.1(+)/NGX6/HT-29 cell was 34.5 hours, which was significantly longer than that of pcDNA3.1(+)/HT-29 cells (27.1 h) and HT-29 cells (23.0 h). FCM data showed that the overexpression of NGX6 blocked the progression of G1→S phase in cell cycle, and it also presented decreased clonogenicity in soft agar assay and tumor formation in nude mice.
CONCLUSION: The re-expression of NGX6 can reverse the malignant phenotype of human colon cancer cell line HT-29. Therefore, NGX6 gene may be a good candidate of tumor suppressor gene associated with colon cancer.
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933
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Abstract
The canonical view of the mammalian cell cycle arose from studies of cultured cells rather than mutant organisms. It depicts the many complexes of cyclin and Cdk (cyclin/Cdk) as fulfilling unique and essential steps that dictate the sequential order of cell cycle events. Recent analyses of knockout mice challenge this view. Cdk2 and cyclin E, long thought to be essential, are largely dispensable. Here, we discuss the phenotypes of these and other cyclin/Cdk mutants in genetically tractable metazoa (mouse, fly, and nematode) and explore possible reasons behind similarities and differences among experimental systems and cell types.
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Affiliation(s)
- Tin Tin Su
- MCD Biology, University of Colorado, Boulder, CO 80309-0347, USA.
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934
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Alonso SR, Ortiz P, Pollán M, Pérez-Gómez B, Sánchez L, Acuña MJ, Pajares R, Martínez-Tello FJ, Hortelano CM, Piris MA, Rodríguez-Peralto JL. Progression in cutaneous malignant melanoma is associated with distinct expression profiles: a tissue microarray-based study. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:193-203. [PMID: 14695333 PMCID: PMC1602212 DOI: 10.1016/s0002-9440(10)63110-0] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cutaneous malignant melanoma remains the leading cause of skin cancer death in industrialized countries. Clinical and histological variables that predict survival, such as Breslow's index, tumor size, ulceration, or vascular invasion have been identified in malignant melanoma. Nevertheless, the potential relevance of biological variables still awaits an in-depth exploration. Using tissue microarrays (TMAs), we retrospectively analyzed 165 malignant melanoma samples from 88 patients corresponding to distinct histological progression phases, radial, vertical, and metastases. A panel of 39 different antibodies for cell cycle, apoptosis, melanoma antigens, transcription factors, DNA mismatch repair, and other proteins was used. Integrating the information, the study has identified expression profiles distinguishing specific melanoma progression stages. Most of the detected alterations were linked to the control of cell cycle G1/S transition; cyclin D1 was expressed in radial cases 48% (12 of 25) with significant lost of expression in vertical cases 14% (9 of 65), P = 0.002; whereas p16(INK4a) (89% in vertical versus 71% in metastatic cases, P = 0.009) and p27(KIP1) (76% in radial versus 45% in vertical cases, P = 0.010) were diminished in advanced stages. The study also defines a combination of biological markers associated with shorter overall survival in patients with vertical growth phase melanoma, that provided a predictor model with four antibodies (Ki67, p16(INK4a), p21(CIP1), and Bcl-6). This predictor model was validated using an independent series of 72 vertical growth phase melanoma patients.
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Affiliation(s)
- Soledad R Alonso
- Molecular Pathology Program and Histology and Immunohistochemistry Unit, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid
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935
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Cassia R, Moreno-Bueno G, Rodríguez-Perales S, Hardisson D, Cigudosa JC, Palacios J. Cyclin E gene (CCNE) amplification and hCDC4 mutations in endometrial carcinoma. J Pathol 2004; 201:589-95. [PMID: 14648662 DOI: 10.1002/path.1474] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cyclin E overexpression occurs in a subset of endometrial carcinomas (ECs), but the molecular mechanisms underlying this alteration remain to be established. The present study has analysed amplification of the cyclin E gene (CCNE) and mutation in hCDC4, the gene coding for the F-box protein, which tags phosphorylated cyclin E for proteosomal degradation, to ascertain whether these alterations might be responsible for cyclin E overexpression in ECs. Cyclin E and p53 expression was studied by immunohistochemistry in eight atypical endometrial hyperplasias (AEHs), 51 endometrioid endometrial carcinomas (EECs), and 22 non-endometrioid endometrial carcinomas (NEECs). CCNE amplification was analysed by fluorescence in situ hybridization (FISH). Mutations in exons 2-11 of the hCDC4 gene were screened by PCR-SSCP-sequencing. Finally, the polymorphic marker D4S1610 was used to assess loss of heterozygosity (LOH) in the hCDC4 gene. Cyclin E overexpression was found in 26/81 (32%) cases and was associated with the histological type of the lesion, since it was not found in any AEHs but was present in 27% of EECs and 54.5% of NEECs (p=0.035). Cyclin E overexpression was associated with histological grade (p=0.011) and p53 immunostaining in EECs (p=0.033). CCNE amplification was found in 6 of 37 (16%) ECs examined. There was a significant association between CCNE amplification and the histological type of the lesion, since five (83%) of the six cases with amplification were NEECs (p=0.008). One EEC harboured an hCDC4 mutation: a CGA to CAA (Arg/Gln) change at codon 479. In addition, D4S1610 LOH was found in 7 of 23 (30%) informative cases analysed, but no correlation with cyclin E overexpression was found. However, the tumour with hCDC4 mutation also showed LOH. This is the first study demonstrating that cyclin E overexpression is associated with gene amplification in ECs, these alterations being more frequent in NEECs. Although hCDC4 exhibits a low mutation frequency in ECs overexpressing cyclin E, it seems to function as a tumour suppressor gene that is involved in endometrial carcinogenesis.
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Affiliation(s)
- Raúl Cassia
- Laboratory of Breast and Gynaecological Cancer, Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
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936
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Tessema M, Lehmann U, Kreipe H. Cell cycle and no end. Virchows Arch 2004; 444:313-23. [PMID: 14968363 DOI: 10.1007/s00428-003-0971-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2003] [Accepted: 12/17/2003] [Indexed: 12/19/2022]
Abstract
Our knowledge about the molecular circuits regulating the duplication of the genetic material and the subsequent division of a cell into two daughter cells has exploded over the last decade. Aberrations in the regulation of the cell cycle belong to the hallmarks of malignant transformation, leading, in turn, to the development of tumours. After introducing the basics of eukaryotic cell-cycle regulation and describing the four phases of the cell cycle (namely, G1, S, G2 and M) in more detail, alterations of key components of the cell-cycle machinery in human malignancies and their functional consequences are presented. Principally, deregulation of the cell cycle can be caused by unrestricted activity of cell-cycle promoting factors (many oncogenes fall into this class) or by inactivation of inhibitory factors (many tumour suppressor genes belong to this class). Both types of deregulation have been described in human tumours and are discussed in detail. Perspectives concerning the translation of this knowledge into daily routine practice and future applications are discussed at the end. The molecular mechanisms of actual cell division (sister chromatid segregation and cytokinesis) are mentioned only briefly.
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Affiliation(s)
- Mathewos Tessema
- Institute of Pathology, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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937
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Wang S, Meades C, Wood G, Osnowski A, Anderson S, Yuill R, Thomas M, Mezna M, Jackson W, Midgley C, Griffiths G, Fleming I, Green S, McNae I, Wu SY, McInnes C, Zheleva D, Walkinshaw MD, Fischer PM. 2-Anilino-4-(thiazol-5-yl)pyrimidine CDK Inhibitors: Synthesis, SAR Analysis, X-ray Crystallography, and Biological Activity. J Med Chem 2004; 47:1662-75. [PMID: 15027857 DOI: 10.1021/jm0309957] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Following the identification through virtual screening of 4-(2,4-dimethyl-thiazol-5-yl)pyrimidin-2-ylamines as moderately potent inhibitors of cyclin-dependent kinase-2 (CDK2), a CDK inhibitor analogue program was initiated. The first aims were to optimize potency and to evaluate the cellular mode of action of lead candidate molecules. Here the synthetic chemistry, the structure-guided design approach, and the structure-activity relationships (SARs) that led to the discovery of 2-anilino-4-(thiazol-5-yl)pyrimidine ATP-antagonistic CDK2 inhibitors, many with very low nM K(i)s against CDK2, are reported. Furthermore, X-ray crystal structures of four representative analogues from our chemical series in complex with CDK2 are presented, and these structures are used to rationalize the observed biochemical SARs. Finally results are reported that show, using the most potent CDK2 inhibitor compound from the current series, that the observed antiproliferative and proapoptotic effects are consistent with cellular CDK2 and CDK9 inhibition.
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Affiliation(s)
- Shudong Wang
- Cyclacel Limited, James Lindsay Place, Dundee DD1 5JJ, Scotland, UK
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938
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Malumbres M, Hunt SL, Sotillo R, Martín J, Odajima J, Martín A, Dubus P, Ortega S, Barbacid M. Driving the cell cycle to cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 532:1-11. [PMID: 12908544 DOI: 10.1007/978-1-4615-0081-0_1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell cycle progression requires the co-ordinated activation of several kinases, some of which are activated upon the binding of a cyclin subunit. At least four of these so-called cyclin-dependent kinases, namely Cdk4, Cdk6, Cdk2 and Cdk1, have specific roles at particular stages of the cell cycle, including passage through the various cell cycle transitions and the response to specific checkpoints. Not surprisingly, most human tumors carry mutations that deregulate at least one of these kinases. To analyze their specific role in vivo, we are generating strains of gene-targeted mice carrying either activated or defective alleles of these Cdks. As an example, Cdk4 expression appears to be expendable in most cell types since mice lacking Cdk4 are viable. Yet, Cdk4 mutant mice are smaller in size and infertile (only partial infertility in males). In addition, Cdk4 defective mice develop insulin dependent diabetes early in life. However, the importance of these Cdks in tumor cell cycles is underscored by the phenotype of knock in mice where the normal Cdk4 gene has been replaced by a Cdk4 R24C (insensitive to INK inhibitors) mutant. These animals develop a wide spectrum of spontaneous tumors and are highly susceptible to specific carcinogenic treatments. These models are being used now to understand how deregulation of these Cdks leads to cancer development and will be a valuable tool to design and validate new therapeutic strategies against tumour development.
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Affiliation(s)
- Marcos Malumbres
- Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas, Madrid, Spain.
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939
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Wan Y, Hur W, Cho CY, Liu Y, Adrian FJ, Lozach O, Bach S, Mayer T, Fabbro D, Meijer L, Gray NS. Synthesis and Target Identification of Hymenialdisine Analogs. ACTA ACUST UNITED AC 2004; 11:247-59. [PMID: 15123286 DOI: 10.1016/j.chembiol.2004.01.015] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2003] [Revised: 11/18/2003] [Accepted: 11/24/2003] [Indexed: 02/01/2023]
Abstract
Hymenialdisine (HMD) is a sponge-derived natural product kinase inhibitor with nanomolar activity against CDKs, Mek1, GSK3beta, and CK1 and micromolar activity against Chk1. In order to explore the broader application of the pyrrolo[2,3-c]azepine skeleton of HMD as a general kinase inhibitory scaffold, we searched for additional protein targets using affinity chromatography in conjunction with the synthesis of diverse HMD analogs and profiled HMD against a panel of 60 recombinant enzymes. This effort has led to nanomolar to micromolar inhibitors of 11 new targets including p90RSK, KDR, c-Kit, Fes, MAPK1, PAK2, PDK1, PKCtheta, PKD2, Rsk1, and SGK. The synthesis of HMD analogs has resulted in the identification of compounds with enhanced and/or dramatically altered selectivities relative to HMD (28n) and in molecules with antiproliferative activities 30-fold higher than HMD (28p).
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Affiliation(s)
- Yongqin Wan
- Genomics Institute of the Novartis Research Foundation, Department of Chemistry, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA
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940
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The discovery of a new structural class of cyclin-dependent kinase inhibitors, aminoimidazo[1,2- a]pyridines. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.1.3.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The protein kinase family represents an enormous opportunity for drug development. However, the current limitation in structural diversity of kinase inhibitors has complicated efforts to identify effective treatments of diseases that involve protein kinase signaling pathways. We have identified a new structural class of protein serine/threonine kinase inhibitors comprising an aminoimidazo[1,2-a]pyridine nucleus. In this report, we describe the first successful use of this class of aza-heterocycles to generate potent inhibitors of cyclin-dependent kinases that compete with ATP for binding to a catalytic subunit of the protein. Co-crystal structures of CDK2 in complex with lead compounds reveal a unique mode of binding. Using this knowledge, a structure-based design approach directed this chemical scaffold toward generating potent and selective CDK2 inhibitors, which selectively inhibited the CDK2-dependent phosphorylation of Rb and induced caspase-3-dependent apoptosis in HCT 116 tumor cells. The discovery of this new class of ATP-site-directed protein kinase inhibitors, aminoimidazo[1,2-a]pyridines, provides the basis for a new medicinal chemistry tool to be used in the search for effective treatments of cancer and other diseases that involve protein kinase signaling pathways.
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941
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Abstract
Eukaryotic organisms depend on an intricate and evolutionary conserved cell cycle to control cell division. The cell cycle is regulated by a number of important protein families which are common targets for mutational inactivation or overexpression in human tumours. The cyclin D and E families and their cyclin-dependent kinase partners initiate the phosphorylation of the retinoblastoma tumour suppressor protein and subsequent transition through the cell cycle. Cyclin/cdk activity and therefore control of cell division is restrained by two families of cyclin dependent kinase inhibitors. A greater understanding of the cell cycle has led to the development of a number of compounds with the potential to restore control of cell division in human cancers. This review will introduce the protein families that regulate the cell cycle, their aberrations in malignant progression and pharmacological strategies targeting this important process.
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Affiliation(s)
- Charles Swanton
- Royal Marsden Hospital Breast Unit, Royal Marsden Hospital NHS Trust, London, UK.
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942
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Musgrove EA, Davison EA, Ormandy CJ. Role of the CDK inhibitor p27 (Kip1) in mammary development and carcinogenesis: insights from knockout mice. J Mammary Gland Biol Neoplasia 2004; 9:55-66. [PMID: 15082918 DOI: 10.1023/b:jomg.0000023588.55733.84] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The cyclin-dependent kinase inhibitor p27 (Kip1) is an important cell cycle regulatory gene in breast cancer, and decreased p27 expression is associated with poor prognosis. Some investigations of its role in mammary development have demonstrated reduced cyclin D1 expression and consequent lack of lobuloalveolar development, but others have found increased cyclin E-Cdk2 activity and increased proliferation balanced by increased apoptosis. It is unclear at present why these apparently divergent results have been obtained. Mice with reduced p27 gene dosage alone do not develop mammary carcinomas but do display substantially shorter tumor latency upon overexpression of erbB2, consistent with a role for p27 as a mammary tumor suppressor gene. In this review we summarize these and other data addressing the role of p27 in normal mammary epithelium and experimental models of mammary carcinogenesis.
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Affiliation(s)
- Elizabeth A Musgrove
- Cancer Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia.
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943
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Sappal DS, McClendon AK, Fleming JA, Thoroddsen V, Connolly K, Reimer C, Blackman RK, Bulawa CE, Osheroff N, Charlton P, Rudolph-Owen LA. Biological characterization of MLN944: A potent DNA binding agent. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.47.3.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
MLN944 (XR5944) is a novel bis-phenazine that has demonstrated exceptional efficacy against a number of murine and human tumor models. The drug was reported originally as a dual topoisomerase I/II poison, but a precise mechanism of action for this compound remains to be determined. Several lines of evidence, including the marginal ability of MLN944 to stabilize topoisomerase-dependent cleavage, and the sustained potency of MLN944 in mammalian cells with reduced levels of both topoisomerases, suggest that other activities of the drug exist. In this study, we show that MLN944 intercalates into DNA, but has no effect on the catalytic activity of either topoisomerase I or II. MLN944 displays no significant ability to stimulate DNA scission mediated by either topoisomerase I or II compared with camptothecin or etoposide, respectively. In addition, yeast genetic models also point toward a topoisomerase-independent mechanism of action. To examine cell cycle effects, synchronized human HCT116 cells were treated with MLN944, doxorubicin, camptothecin, or a combination of the latter two to mimic a dual topoisomerase poison. MLN944 treatment was found to induce a G1 and G2 arrest in cells that is unlike the typical G2-M arrest noted with known topoisomerase poisons. Finally, transcriptional profiling analysis of xenograft tumors treated with MLN944 revealed clusters of regulated genes distinct from those observed in irinotecan hydrochloride (CPT-11)-treated tumors. Taken together, these findings suggest that the primary mechanism of action of MLN944 likely involves DNA binding and intercalation, but does not appear to involve topoisomerase inhibition.
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Affiliation(s)
| | | | | | | | - Kelly Connolly
- 3Cancer Pharmacology, Millennium Pharmaceuticals, Inc., Cambridge, MA
| | - Corinne Reimer
- 3Cancer Pharmacology, Millennium Pharmaceuticals, Inc., Cambridge, MA
| | | | | | - Neil Osheroff
- 5Biochemistry and Departments of
- 6Medicine, Vanderbilt University School of Medicine, Nashville, TN
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944
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Abstract
The D-type and E-type cyclins control the G(1) to S phase transition during normal cell cycle progression and are critical components of steroid- and growth factor-induced mitogenesis in breast epithelial cells. Mammary epithelial cell-specific overexpression of these genes leads to mammary carcinoma, while in cyclin D1-deficient mice mammary gland development is arrested prior to lobuloalveolar development. Cyclin D1 null mice are resistant to mammary carcinoma induced by the neu and ras oncogenes, indicating an essential role for cyclin D1 in the development of some mammary cancers. Cyclin D1 and E1 are commonly overexpressed in primary breast cancer, with some evidence of an association with an adverse patient outcome. This observation may result in part from their ability to confer resistance to endocrine therapies. The functional consequences of cyclin E overexpression in breast cancer are likely related to its role in cell cycle progression, whereas that of cyclin D1 may also be a consequence of a more recently defined role in transcriptional regulation.
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Affiliation(s)
- Robert L Sutherland
- Cancer Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, Sydney, Australia.
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945
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Chim CS, Fung TK, Liang R. Disruption of INK4/CDK/Rb cell cycle pathway by gene hypermethylation in multiple myeloma and MGUS. Leukemia 2003; 17:2533-5. [PMID: 12970764 DOI: 10.1038/sj.leu.2403133] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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946
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Sengupta J, Dhawan L, Lalitkumar PGL, Ghosh D. A multiparametric study of the action of mifepristone used in emergency contraception using the Rhesus monkey as a primate model. Contraception 2003; 68:453-69. [PMID: 14698076 DOI: 10.1016/s0010-7824(03)00108-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mifepristone is a potent agent used in emergency contraception (EC). In the present study, we examined the contraceptive efficacy of mifepristone used in EC and then, using the model of mifepristone-based EC, we investigated its mechanism of action in the rhesus monkey. Sexually mature females were allowed to cohabitate with male animals from 1600 to 900 h of any one day of days 8-17 of cycle without (Group I; n = 6) and with a single dose of mifepristone (Group II, n = 31, 25 mg per animal, subcutaneous) 72 h postcoitus. Blood samples from all animals of Groups I and II were used to determine the concentrations of estradiol (E), progesterone (P) and chorionic gonadotrophin in peripheral circulation for retrospective analysis of the days of ovulation and blastocyst implantation. Four out of six animals (66.6%) in Group I became pregnant, while all 31 monkeys in Group II failed to establish pregnancy along with marginal changes in serum concentrations of E and P. In the second part of the study, animals were subjected to the same experimental protocol followed by collection of endometrial tissue samples on cycle day 22 from animals of both Group I (n = 6) and Group II (n = 24). Endometrial samples were subjected to morphological analysis including mitotic index, immunohistochemistry for vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), transforming growth factor beta1, estradiol receptor (ER), progesterone receptor (PR), proliferating cell nuclear antigen, placental protein 14 (PP 14) and detection of apoptosis by terminal nick end labeling method followed by histometric analysis. The results were retrospectively analyzed between the two groups on the basis of the day of treatment after ovulation: early luteal phase (days 0-3 postovulation) and mid-luteal phase (days 4-7 after ovulation). Mifepristone used in EC in the present study resulted in general loss of functional integrity of epithelial compartment characterized by loss of secretory maturation, increased apoptosis and higher degree of degeneration along with decreased expression of VEGF, LIF, PP14 and ER, while PR level increased as compared to control samples. The vascular compartment appeared to be compromised along with affected morphological features and decreased expression of VEGF, LIF, ER and PR following the administration of mifepristone. It appears that mifepristone used in EC alters the physiological homeostasis in epithelial and vascular compartments of implantation stage endometrium rendering it hostile to blastocyst implantation. Furthermore, the degree to which the endometrial function is affected largely depends on the day of mifepristone treatment in a parameter-specific manner resulting in a higher degree of degenerative changes in samples obtained from animals who received mifepristone during mid-luteal phase of cycles.
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Affiliation(s)
- Jayasree Sengupta
- Department of Physiology, All India Institute of Medical Sciences, New Delhi 110029, India
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947
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Szremska AP, Kenner L, Weisz E, Ott RG, Passegué E, Artwohl M, Freissmuth M, Stoxreiter R, Theussl HC, Parzer SB, Moriggl R, Wagner EF, Sexl V. JunB inhibits proliferation and transformation in B-lymphoid cells. Blood 2003; 102:4159-65. [PMID: 12907453 DOI: 10.1182/blood-2003-03-0915] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The activator protein 1 (AP-1) member JunB has recently been implicated in leukemogenesis. Here we surveyed human lymphoma samples for expression of JunB and other AP-1 members (c-Jun, c-Fos, Fra1, JunD). JunB was strongly expressed in T-cell lymphomas, but non-Hodgkin B-cell lymphomas do not or only weakly express JunB. We therefore asked whether JunB acted as a negative regulator of B-cell development, proliferation, and transformation. We used transgenic mice that expressed JunB under the control of the ubiquitin C promoter; these displayed increased JunB levels in both B- and T-lymphoid cells. JunB transgenic cells of B-lymphoid, but not of T-lymphoid, origin responded poorly to mitogenic stimuli. Furthermore, JunB transgenic cells were found to be less susceptible to the transforming potential of the Abelson oncogene in vitro. In addition, overexpression of JunB partially protected transgenic mice against the oncogenic challenge in vivo. However, transformed B cells eventually escaped from the inhibitory effect of JunB: the proliferative response was similar in explanted tumor-derived cells from transgenic animals and those from wild-type controls. Our results identify JunB as a novel regulator of B-cell proliferation and transformation.
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Affiliation(s)
- Agnieszka P Szremska
- Department of Pharmacology, Vienna University, Währingerstrasse 13A, A-1090 Vienna, Austria
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948
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Cao MY, Lee Y, Feng NP, Al-Qawasmeh RA, Viau S, Gu XP, Lau L, Jin H, Wang M, Vassilakos A, Wright JA, Young AH. NC381, a Novel Anticancer Agent, Arrests the Cell Cycle in G0-G1 and Inhibits Lung Tumor Cell Growth in Vitro and in Vivo. J Pharmacol Exp Ther 2003; 308:538-46. [PMID: 14610220 DOI: 10.1124/jpet.103.059618] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although clotrimazole (CLT), an antifungal drug, inhibits tumor cell proliferation and angiogenesis, its clinical application is hampered by significant hepatotoxicity due to the presence of an imidazole moiety. In our attempts to develop CLT analogs that are devoid of imidazole and are as efficacious as CLT, one pharmacophore designated NC381 was generated and shown to inhibit tumor cell growth via a mechanism similar to that of CLT. In vitro, treatment of NCI-H460 nonsmall cell lung cancer (NSCLC) cells with NC381 inhibited growth in a time-dependent manner. Flow cytometric analysis demonstrated that the decrease in cell growth was associated with inhibition of cell cycle progression at the G(1)-S phase transition, resulting in G(0)-G(1) arrest. There was a concomitant inhibition of cyclin D1 expression and subsequent reduction in the formation of the cyclin D1-CDK4 complex. Consistent with a decrease in the cyclin D1-CDK4 complex, NC381 treatment resulted in significant inhibition of pRb phosphorylation. There also were changes in the activity of cell cycle-related proteins, including p16(Ink4) and p27(Kip1). Together, these results are consistent with a model in which NC381 arrests cell cycle progression via inhibition of the pathway that promotes exit from the G(1) phase of the cell cycle. Furthermore, the clinical applicability of NC381 was evaluated in an in vivo murine xenograft model of human NSCLC (NCI-H460). NC381 treatment resulted in significant inhibition of tumor growth. Given the poor prognosis and the limited treatment options available, the present results underscore the potential of NC381 in the treatment of human NSCLC.
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Affiliation(s)
- Ming-Yu Cao
- Lorus Therapeutics Inc., Toronto, ON, Canada, M9W 4Z7.
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949
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Kwak JC, Ongusaha PP, Ouchi T, Lee SW. IFI16 as a negative regulator in the regulation of p53 and p21(Waf1). J Biol Chem 2003; 278:40899-904. [PMID: 12925527 DOI: 10.1074/jbc.m308012200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
IFI16 is a member of the HIN-200 family (hematopoietic interferon-inducible nuclear antigens with 200 amino acid repeats) that contains a DNA binding domain, a transcriptional regulatory domain, and DAPIN/PAAD, a protein domain associated with interferon response. It can function as a transcription repressor and directly binds p53. Although the structural and biochemical properties of IFI16 are known, the physiological relevance of these properties in the cellular context is still elusive. Here we report that the inhibition of endogenous IFI16 expression by small interfering RNA (siRNA) induces p21Waf1 mRNA and protein expression through p53 but does not induce pro-apoptotic p53 target genes. This rapid induction of p21 was wild-type p53-dependent and resulted in cell cycle arrest along with a marked reduction of phosphorylated Rb in normally growing cells. We also showed that the repression of IFI16 affects p53 transcriptional activity at the p21 promoter as well as the protein stability of p53 and p21. Our findings identified a new role for IFI16 in modulating p53 function and its target gene regulation in the control of cell cycle regulation.
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Affiliation(s)
- Jennifer C Kwak
- Hematology and Oncology Division, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA
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950
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Affiliation(s)
- Ji Luo
- Howard Hughes Medical Institute, USA
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