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Abstract
Mouse models of colorectal cancer (CRC) have been crucial in the identification of the role of genes responsible for the full range of pathology of the human disease and have proved to be dependable for testing anti-cancer drugs. Recent research points toward the relevance of tumor, angiogenic, and immune microenvironments in CRC progression to late-stage disease, as well as the treatment of it. This study examines important mouse models in CRC, discussing inherent strengths and weaknesses disclosed during their construction. It endeavors to provide both a synopsis of previous work covering how investigators have defined various models and to evaluate critically how researchers are most likely to use them in the future. Accumulated evidence regarding the metastatic process and the hope of using checkpoint inhibitors and immunological inhibitor therapies points to the need for a genetically engineered mouse model that is both immunocompetent and autochthonous.
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Affiliation(s)
- Melanie Haas Kucherlapati
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Medicine, Division of Genetics, Brigham and Women’s Hospital, Boston, MA, USA
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2
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Garside GB, Sandoval M, Beronja S, Rudolph KL. Lentiviral in situ targeting of stem cells in unperturbed intestinal epithelium. BMC Biol 2023; 21:6. [PMID: 36627630 PMCID: PMC9832770 DOI: 10.1186/s12915-022-01466-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 11/16/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Methods for the long-term in situ transduction of the unperturbed murine intestinal epithelium have not been developed in past research. Such a method could speed up functional studies and screens to identify genetic factors influencing intestinal epithelium biology. Here, we developed an efficient method achieving this long-sought goal. RESULTS We used ultrasound-guided microinjections to transduce the embryonic endoderm at day 8 (E8.0) in utero. The injection procedure can be completed in 20 min and had a 100% survival rate. By injecting a small volume (0.1-0.2 μl) of concentrated virus, single shRNA constructs as well as lentiviral libraries can successfully be transduced. The new method stably and reproducibly targets adult intestinal epithelium, as well as other endoderm-derived organs such as the lungs, pancreas, liver, stomach, and bladder. Postnatal analysis of young adult mice indicates that single transduced cells at E8.0 gave rise to crypt fields that were comprised of 20-30 neighbouring crypts per crypt-field at 90 days after birth. Lentiviral targeting of ApcMin/+ mutant and wildtype mice revealed that heterozygous loss of Apc function suppresses the developmental normal growth pattern of intestinal crypt fields. This suppression of crypt field sizes did not involve a reduction of the crypt number per field, indicating that heterozygous Apc loss impaired the growth of individual crypts within the fields. Lentiviral-mediated shRNA knockdown of p53 led to an approximately 20% increase of individual crypts per field in both Apc+/+ and ApcMin/+ mice, associating with an increase in crypt size in ApcMin/+ mice but a slight reduction in crypt size in Apc+/+ mice. Overall, p53 knockdown rescued the reduction in crypt field size in Apc-mutant mice but had no effect on crypt field size in wildtype mice. CONCLUSIONS This study develops a novel technique enabling robust and reproducible in vivo targeting of intestinal stem cells in situ in the unperturbed intestinal epithelium across different regions of the intestine. In vivo somatic gene editing and genetic screening of lentiviral libraries has the potential to speed up discoveries and mechanistic understanding of genetic pathways controlling the biology of the intestinal epithelium during development and postnatal life. The here developed method enables such approaches.
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Affiliation(s)
- George B. Garside
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany
- National Center for Tumor Diseases, 01307 Dresden, Germany
| | - Madeline Sandoval
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA 98109 USA
| | - Slobodan Beronja
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA 98109 USA
| | - K. Lenhard Rudolph
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany
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3
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Nakayama M, Oshima M. Mutant p53 in colon cancer. J Mol Cell Biol 2020; 11:267-276. [PMID: 30496442 PMCID: PMC6487790 DOI: 10.1093/jmcb/mjy075] [Citation(s) in RCA: 154] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 11/13/2018] [Accepted: 11/27/2018] [Indexed: 12/13/2022] Open
Abstract
The accumulation of genetic alterations in driver genes is responsible for the development and malignant progression of colorectal cancer. Comprehensive genome analyses have revealed the driver genes, including APC, KRAS, TGFBR2, and TP53, whose mutations are frequently found in human colorectal cancers. Among them, the p53 mutation is found in ~60% of colorectal cancers, and a majority of mutations are missense-type at ‘hot spots’, suggesting an oncogenic role of mutant p53 by ‘gain-of-function’ mechanisms. Mouse model studies have shown that one of these missense-type mutations, p53 R270H (corresponding to human R273H), causes submucosal invasion of intestinal tumors, while the loss of wild-type p53 has a limited effect on the invasion process. Furthermore, the same mutant p53 promotes metastasis when combined with Kras activation and TGF-β suppression. Importantly, either missense-type p53 mutation or loss of wild-type p53 induces NF-κB activation by a variety of mechanisms, such as increasing promoter accessibility by chromatin remodeling, which may contribute to progression to epithelial–mesenchymal transition. These results indicate that missense-type p53 mutations together with loss of wild-type p53 accelerate the late stage of colorectal cancer progression through the activation of both oncogenic and inflammatory pathways. Accordingly, the suppression of the mutant p53 function via the inhibition of nuclear accumulation is expected to be an effective strategy against malignant progression of colorectal cancer.
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Affiliation(s)
- Mizuho Nakayama
- Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.,WPI-Nano Life Science Institute, Kanazawa University, Kanazawa, Japan
| | - Masanobu Oshima
- Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.,WPI-Nano Life Science Institute, Kanazawa University, Kanazawa, Japan
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4
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Bürtin F, Mullins CS, Linnebacher M. Mouse models of colorectal cancer: Past, present and future perspectives. World J Gastroenterol 2020; 26:1394-1426. [PMID: 32308343 PMCID: PMC7152519 DOI: 10.3748/wjg.v26.i13.1394] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer (CRC) is the third most common diagnosed malignancy among both sexes in the United States as well as in the European Union. While the incidence and mortality rates in western, high developed countries are declining, reflecting the success of screening programs and improved treatment regimen, a rise of the overall global CRC burden can be observed due to lifestyle changes paralleling an increasing human development index. Despite a growing insight into the biology of CRC and many therapeutic improvements in the recent decades, preclinical in vivo models are still indispensable for the development of new treatment approaches. Since the development of carcinogen-induced rodent models for CRC more than 80 years ago, a plethora of animal models has been established to study colon cancer biology. Despite tenuous invasiveness and metastatic behavior, these models are useful for chemoprevention studies and to evaluate colitis-related carcinogenesis. Genetically engineered mouse models (GEMM) mirror the pathogenesis of sporadic as well as inherited CRC depending on the specific molecular pathways activated or inhibited. Although the vast majority of CRC GEMM lack invasiveness, metastasis and tumor heterogeneity, they still have proven useful for examination of the tumor microenvironment as well as systemic immune responses; thus, supporting development of new therapeutic avenues. Induction of metastatic disease by orthotopic injection of CRC cell lines is possible, but the so generated models lack genetic diversity and the number of suited cell lines is very limited. Patient-derived xenografts, in contrast, maintain the pathological and molecular characteristics of the individual patient’s CRC after subcutaneous implantation into immunodeficient mice and are therefore most reliable for preclinical drug development – even in comparison to GEMM or cell line-based analyses. However, subcutaneous patient-derived xenograft models are less suitable for studying most aspects of the tumor microenvironment and anti-tumoral immune responses. The authors review the distinct mouse models of CRC with an emphasis on their clinical relevance and shed light on the latest developments in the field of preclinical CRC models.
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Affiliation(s)
- Florian Bürtin
- Department of General, Visceral, Vascular and Transplantation Surgery, University Medical Center Rostock, University of Rostock, Rostock 18057, Germany
| | - Christina S Mullins
- Department of Thoracic Surgery, University Medical Center Rostock, University of Rostock, Rostock 18057, Germany
| | - Michael Linnebacher
- Molecular Oncology and Immunotherapy, Department of General, Visceral, Vascular and Transplantation Surgery, University Medical Center Rostock, Rostock 18057, Germany
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Venkatachalam K, Vinayagam R, Arokia Vijaya Anand M, Isa NM, Ponnaiyan R. Biochemical and molecular aspects of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis: a review. Toxicol Res (Camb) 2020; 9:2-18. [PMID: 32440334 DOI: 10.1093/toxres/tfaa004] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 01/20/2020] [Accepted: 02/12/2020] [Indexed: 02/07/2023] Open
Abstract
1,2-dimethylhydrazine (DMH) is a member in the class of hydrazines, strong DNA alkylating agent, naturally present in cycads. DMH is widely used as a carcinogen to induce colon cancer in animal models. Exploration of DMH-induced colon carcinogenesis in rodent models provides the knowledge to perceive the biochemical, molecular, and histological mechanisms of different stages of colon carcinogenesis. The procarcinogen DMH, after a series of metabolic reactions, finally reaches the colon, there produces the ultimate carcinogen and reactive oxygen species (ROS), which further alkylate the DNA and initiate the development of colon carcinogenesis. The preneolpastic lesions and histopathological observations of DMH-induced colon tumors may provide typical understanding about the disease in rodents and humans. In addition, this review discusses about the action of biotransformation and antioxidant enzymes involved in DMH intoxication. This understanding is essential to accurately identify and interpret alterations that occur in the colonic mucosa when evaluating natural or pharmacological compounds in DMH-induced animal colon carcinogenesis.
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Affiliation(s)
- Karthikkumar Venkatachalam
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, UAE University, Al Ain-17666, United Arab Emirates
| | - Ramachandran Vinayagam
- Department of Biotechnology, Thiruvalluvar University, Serkadu, Vellore, Tamilnadu 632 115, India
| | | | - Nurulfiza Mat Isa
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, 43400 Seri Kembangan, Selangor, Malaysia
| | - Rajasekar Ponnaiyan
- Department of Zoology, Jamal Mohamed College, Tiruchirappalli, Tamil Nadu 620020, India
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Nilton A, Sayin VI, Zou ZV, Sayin SI, Bondjers C, Gul N, Agren P, Fogelstrand P, Nilsson O, Bergo MO, Lindahl P. Targeting Zfp148 activates p53 and reduces tumor initiation in the gut. Oncotarget 2018; 7:56183-56192. [PMID: 27487143 PMCID: PMC5302905 DOI: 10.18632/oncotarget.10899] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/13/2016] [Indexed: 12/30/2022] Open
Abstract
The transcription factor Zinc finger protein 148 (Zfp148, ZBP-89, BFCOL, BERF1, htβ) interacts physically with the tumor suppressor p53, but the significance of this interaction is not known. We recently showed that knockout of Zfp148 in mice leads to ectopic activation of p53 in some tissues and cultured fibroblasts, suggesting that Zfp148 represses p53 activity. Here we hypothesize that targeting Zfp148 would unleash p53 activity and protect against cancer development, and test this idea in the APCMin/+ mouse model of intestinal adenomas. Loss of one copy of Zfp148 markedly reduced tumor numbers and tumor-associated intestinal bleedings, and improved survival. Furthermore, after activation of β-catenin-the initiating event in colorectal cancer-Zfp148 deficiency activated p53 and induced apoptosis in intestinal explants of APCMin/+ mice. The anti-tumor effect of targeting Zfp148 depended on p53, as Zfp148 deficiency did not affect tumor numbers in APCMin/+ mice lacking one or both copies of Trp53. The results suggest that Zfp148 controls the fate of newly transformed intestinal tumor cells by repressing p53 and that targeting Zfp148 might be useful in the treatment of colorectal cancer.
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Affiliation(s)
- Anna Nilton
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Volkan I Sayin
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden.,Department of Biochemistry, Institute of Biomedicine, Gothenburg, Sweden
| | - Zhiyuan V Zou
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Sama I Sayin
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Cecilia Bondjers
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Nadia Gul
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Pia Agren
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Per Fogelstrand
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Ola Nilsson
- Sahlgrenska Cancer Center, Institute of Biomedicine, Department of Pathology and Genetics, Gothenburg, Sweden
| | - Martin O Bergo
- Sahlgrenska Cancer Center, Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Per Lindahl
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden.,Department of Biochemistry, Institute of Biomedicine, Gothenburg, Sweden
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7
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Georgescu MM, Gagea M, Cote G. NHERF1/EBP50 Suppresses Wnt-β-Catenin Pathway-Driven Intestinal Neoplasia. Neoplasia 2017; 18:512-23. [PMID: 27566107 PMCID: PMC5018097 DOI: 10.1016/j.neo.2016.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 07/01/2016] [Accepted: 07/11/2016] [Indexed: 12/31/2022] Open
Abstract
NHERF1/EBP50, an adaptor molecule that interacts with β-catenin, YAP, and PTEN, has been recently implicated in the progression of various human malignancies, including colorectal cancer. We report here that NHERF1 acts as a tumor suppressor in vivo for intestinal adenoma development. NHERF1 is highly expressed at the apical membrane of mucosa intestinal epithelial cells (IECs) and serosa mesothelial cells. NHERF1-deficient mice show overall longer small intestine and colon that most likely could be attributed to a combination of defects, including altered apical brush border of absorbtive IECs and increased number of secretory IECs. NHERF1 deficiency in Apc(Min/+) mice resulted in significantly shorter animal survival due to markedly increased tumor burden. This resulted from a moderate increase of the overall tumor density, more pronounced in females than males, and a massive increase in the number of large adenomas in both genders. The analysis of possible pathways controlling tumor size showed upregulation of Wnt-β-catenin pathway, higher expression of unphosphorylated YAP, and prominent nuclear expression of cyclin D1 in NHERF1-deficient tumors. Similar YAP changes, with relative decrease of phosphorylated YAP and increase of nuclear YAP expression, were observed as early as the adenoma stages in the progression of human colorectal cancer. This study discusses a complex role of NHERF1 for intestinal morphology and presents indisputable evidence for its in vivo tumor suppressor function upstream of Wnt-β-catenin and Hippo-YAP pathways.
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Affiliation(s)
- Maria-Magdalena Georgescu
- Department of Pathology and Translational Pathobiology, Louisiana State University, Shreveport, LA, 71103, USA.
| | - Mihai Gagea
- Department of Veterinary Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Gilbert Cote
- Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
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8
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Kuo TL, Weng CC, Kuo KK, Chen CY, Wu DC, Hung WC, Cheng KH. APC haploinsufficiency coupled with p53 loss sufficiently induces mucinous cystic neoplasms and invasive pancreatic carcinoma in mice. Oncogene 2016; 35:2223-34. [PMID: 26411367 DOI: 10.1038/onc.2015.284] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 06/03/2015] [Accepted: 06/22/2015] [Indexed: 12/23/2022]
Abstract
Adenomatous polyposis coli (APC), a tumor-suppressor gene critically involved in familial adenomatous polyposis, is integral in Wnt/β-catenin signaling and is implicated in the development of sporadic tumors of the distal gastrointestinal tract including pancreatic cancer (PC). Here we report for the first time that functional APC is required for the growth and maintenance of pancreatic islets and maturation. Subsequently, a non-Kras mutation-induced premalignancy mouse model was developed; in this model, APC haploinsufficiency coupled with p53 deletion resulted in the development of a distinct type of pancreatic premalignant precursors, mucinous cystic neoplasms (MCNs), exhibiting pathomechanisms identical to those observed in human MCNs, including accumulation of cystic fluid secreted by neoplastic and ovarian-like stromal cells, with 100% penetrance and the presence of hepatic and gastric metastases in >30% of the mice. The major clinical implications of this study suggest targeting the Wnt signaling pathway as a novel strategy for managing MCN.
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Affiliation(s)
- T-L Kuo
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - C-C Weng
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - K-K Kuo
- Division of Hepatobiliopancreatic Surgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - C-Y Chen
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Medical Imaging, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - D-C Wu
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Division of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - W-C Hung
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - K-H Cheng
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
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Applegate CC, Lane MA. Role of retinoids in the prevention and treatment of colorectal cancer. World J Gastrointest Oncol 2015; 7:184-203. [PMID: 26483874 PMCID: PMC4606174 DOI: 10.4251/wjgo.v7.i10.184] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/10/2015] [Accepted: 09/16/2015] [Indexed: 02/05/2023] Open
Abstract
Vitamin A and its derivatives, retinoids, have been widely studied for their use as cancer chemotherapeutic agents. With respect to colorectal cancer (CRC), several critical mutations dysregulate pathways implicated in progression and metastasis, resulting in aberrant Wnt/β-catenin signaling, gain-of-function mutations in K-ras and phosphatidylinositol-3-kinase/Akt, cyclooxygenase-2 over-expression, reduction of peroxisome proliferator-activated receptor γ activation, and loss of p53 function. Dysregulation leads to increased cellular proliferation and invasion and decreased cell-cell interaction and differentiation. Retinoids affect these pathways by various mechanisms, many involving retinoic acid receptors (RAR). RAR bind to all-trans-retinoic acid (ATRA) to induce the transcription of genes responsible for cellular differentiation. Although most research concerning the chemotherapeutic efficacy of retinoids focuses on the ability of ATRA to decrease cancer cell proliferation, increase differentiation, or promote apoptosis; as CRC progresses, RAR expression is often lost, rendering treatment of CRCs with ATRA ineffective. Our laboratory focuses on the ability of dietary vitamin A to decrease CRC cell proliferation and invasion via RAR-independent pathways. This review discusses our research and others concerning the ability of retinoids to ameliorate the defective signaling pathways listed above and decrease tumor cell proliferation and invasion through both RAR-dependent and RAR-independent mechanisms.
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Chanrion M, Kuperstein I, Barrière C, El Marjou F, Cohen D, Vignjevic D, Stimmer L, Paul-Gilloteaux P, Bièche I, Tavares SDR, Boccia GF, Cacheux W, Meseure D, Fre S, Martignetti L, Legoix-Né P, Girard E, Fetler L, Barillot E, Louvard D, Zinovyev A, Robine S. Concomitant Notch activation and p53 deletion trigger epithelial-to-mesenchymal transition and metastasis in mouse gut. Nat Commun 2014; 5:5005. [PMID: 25295490 PMCID: PMC4214431 DOI: 10.1038/ncomms6005] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 08/15/2014] [Indexed: 12/31/2022] Open
Abstract
Epithelial-to-mesenchymal transition-like (EMT-like) is a critical process allowing initiation of metastases during tumour progression. Here, to investigate its role in intestinal cancer, we combine computational network-based and experimental approaches to create a mouse model with high metastatic potential. Construction and analysis of this network map depicting molecular mechanisms of EMT regulation based on the literature suggests that Notch activation and p53 deletion have a synergistic effect in activating EMT-like processes. To confirm this prediction, we generate transgenic mice by conditionally activating the Notch1 receptor and deleting p53 in the digestive epithelium (NICD/p53(-/-)). These mice develop metastatic tumours with high penetrance. Using GFP lineage tracing, we identify single malignant cells with mesenchymal features in primary and metastatic tumours in vivo. The development of such a model that recapitulates the cellular features observed in invasive human colorectal tumours is appealing for innovative drug discovery.
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Affiliation(s)
- Maia Chanrion
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - Inna Kuperstein
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Inserm, U900, Paris 75248, France
| | - Cédric Barrière
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - Fatima El Marjou
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - David Cohen
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Inserm, U900, Paris 75248, France
| | - Danijela Vignjevic
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - Lev Stimmer
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - Perrine Paul-Gilloteaux
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Cell and Tissue Imaging Facility, PICT-IBiSA, CNRS, UMR 144, Paris 75248, France
| | - Ivan Bièche
- 1] Inserm U735, Hôpital René Huguenin, 92210 Saint-Cloud, France [2] Institut Curie, Hôpital René Huguenin, 35 rue Dailly, 92210 Saint-Cloud, France
| | - Silvina Dos Reis Tavares
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - Giuseppe-Fulvio Boccia
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | | | | | - Silvia Fre
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR3215, Paris 75248, France [3] Inserm U934, Paris 75248, France
| | - Loredana Martignetti
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Inserm, U900, Paris 75248, France
| | - Patricia Legoix-Né
- Next-Generation Sequencing Platform, Institut Curie, Paris 75248, France
| | - Elodie Girard
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Inserm, U900, Paris 75248, France
| | - Luc Fetler
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR168, Paris 75248, France
| | - Emmanuel Barillot
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Inserm, U900, Paris 75248, France
| | - Daniel Louvard
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
| | - Andreï Zinovyev
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] Inserm, U900, Paris 75248, France
| | - Sylvie Robine
- 1] Institut Curie, Centre de Recherche, Paris 75248, France [2] CNRS UMR 144, Paris 75248, France
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11
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Gala MK, Mizukami Y, Le LP, Moriichi K, Austin T, Yamamoto M, Lauwers GY, Bardeesy N, Chung DC. Germline mutations in oncogene-induced senescence pathways are associated with multiple sessile serrated adenomas. Gastroenterology 2014; 146:520-9. [PMID: 24512911 PMCID: PMC3978775 DOI: 10.1053/j.gastro.2013.10.045] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Revised: 10/17/2013] [Accepted: 10/21/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Little is known about the genetic factors that contribute to the development of sessile serrated adenomas (SSAs). SSAs contain somatic mutations in BRAF or KRAS early in development. However, evidence from humans and mouse models indicates that these mutations result in oncogene-induced senescence (OIS) of intestinal crypt cells. Progression to serrated neoplasia requires cells to escape OIS via inactivation of tumor suppressor pathways. We investigated whether subjects with multiple SSAs carry germline loss-of function mutations (nonsense and splice site) in genes that regulate OIS: the p16-Rb and ATM-ATR DNA damage response pathways. METHODS Through a bioinformatic analysis of the literature, we identified a set of genes that function at the main nodes of the p16-Rb and ATM-ATR DNA damage response pathways. We performed whole-exome sequencing of 20 unrelated subjects with multiple SSAs; most had features of serrated polyposis. We compared sequences with those from 4300 subjects matched for ethnicity (controls). We also used an integrative genomics approach to identify additional genes involved in senescence mechanisms. RESULTS We identified mutations in genes that regulate senescence (ATM, PIF1, TELO2,XAF1, and RBL1) in 5 of 20 subjects with multiple SSAs (odds ratio, 3.0; 95% confidence interval, 0.9–8.9; P =.04). In 2 subjects,we found nonsense mutations in RNF43, indicating that it is also associated with multiple serrated polyps (odds ratio, 460; 95% confidence interval, 23.1–16,384; P = 6.8 x 10(-5)). In knockdown experiments with pancreatic duct cells exposed to UV light, RNF43 appeared to function as a regulator of ATMATRDNA damage response. CONCLUSIONS We associated germline loss-of-function variants in genes that regulate senescence pathways with the development of multiple SSAs.We identified RNF43 as a regulator of the DNA damage response and associated nonsense variants in this gene with a high risk of developing SSAs.
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Affiliation(s)
- Manish K. Gala
- Massachusetts General Hospital Department of Medicine, G.I. Unit and Harvard Medical School, Boston, MA
| | - Yusuke Mizukami
- Massachusetts General Hospital Department of Medicine, G.I. Unit and Harvard Medical School, Boston, MA,Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA,Center for Clinical and Biomedical Research, Sapporo Higashi Tokushukai Hospital, Sapporo, Japan
| | - Long P. Le
- Massachusetts General Hospital Department of Pathology and Harvard Medical School, Boston, MA
| | - Kentaro Moriichi
- Massachusetts General Hospital Department of Medicine, G.I. Unit and Harvard Medical School, Boston, MA
| | - Thomas Austin
- Massachusetts General Hospital Department of Medicine, G.I. Unit and Harvard Medical School, Boston, MA
| | - Masayoshi Yamamoto
- Massachusetts General Hospital Department of Medicine, G.I. Unit and Harvard Medical School, Boston, MA
| | - Gregory Y. Lauwers
- Massachusetts General Hospital Department of Pathology and Harvard Medical School, Boston, MA
| | - Nabeel Bardeesy
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA
| | - Daniel C. Chung
- Massachusetts General Hospital Department of Medicine, G.I. Unit and Harvard Medical School, Boston, MA,Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA
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12
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Abstract
Animal models for human colorectal cancer recapitulate multistep carcinogenesis that is typically initiated by activation of the Wnt pathway. Although potential roles of both genetic and environmental modifiers have been extensively investigated in vivo, it remains elusive whether epithelial cells definitely require interaction with stromal cells or microflora for tumor development. Here we show that tumor development could be simply induced independently of intestinal microenvironment, even with WT murine primary intestinal cells alone. We developed an efficient method for lentiviral transduction of intestinal organoids in 3D culture. Despite seemingly antiproliferative effects by knockdown of adenomatous polyposis coli (APC), we managed to reproducibly induce APC-inactivated intestinal organoids. As predicted, these organoids were constitutively active in the Wnt signaling pathway and proved tumorigenic when injected into nude mice, yielding highly proliferative tubular epithelial glands accompanied by prominent stromal tissue. Consistent with cellular transformation, tumor-derived epithelial cells acquired sphere formation potential, gave rise to secondary tumors on retransplantation, and highly expressed cancer stem cell markers. Inactivation of p53 or phosphatase and tensin homolog deleted from chromosome 10, or activation of Kras, promoted tumor development only in the context of APC suppression, consistent with earlier genetic studies. These findings clearly indicated that genetic cooperation for intestinal tumorigenesis could be essentially recapitulated in intestinal organoids without generating gene-modified mice. Taken together, this in vitro model for colon cancer described herein could potentially provide unique opportunities for carcinogenesis studies by serving as a substitute or complement to the currently standard approaches.
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13
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Schwitalla S, Ziegler PK, Horst D, Becker V, Kerle I, Begus-Nahrmann Y, Lechel A, Rudolph KL, Langer R, Slotta-Huspenina J, Bader FG, Prazeres da Costa O, Neurath MF, Meining A, Kirchner T, Greten FR. Loss of p53 in enterocytes generates an inflammatory microenvironment enabling invasion and lymph node metastasis of carcinogen-induced colorectal tumors. Cancer Cell 2013; 23:93-106. [PMID: 23273920 DOI: 10.1016/j.ccr.2012.11.014] [Citation(s) in RCA: 215] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 09/17/2012] [Accepted: 11/26/2012] [Indexed: 12/14/2022]
Abstract
Loss of p53 is considered to allow progression of colorectal tumors from the adenoma to the carcinoma stage. Using mice with an intestinal epithelial cell (IEC)-specific p53 deletion, we demonstrate that loss of p53 alone is insufficient to initiate intestinal tumorigenesis but markedly enhances carcinogen-induced tumor incidence and leads to invasive cancer and lymph node metastasis. Whereas p53 controls DNA damage and IEC survival during the initiation stage, loss of p53 during tumor progression is associated with increased intestinal permeability, causing formation of an NF-κB-dependent inflammatory microenvironment and the induction of epithelial-mesenchymal transition. Thus, we propose a p53-controlled tumor-suppressive function that is independent of its well-established role in cell-cycle regulation, apoptosis, and senescence.
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Affiliation(s)
- Sarah Schwitalla
- Institute of Molecular Immunology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
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14
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Krepkin K, Costa J. Defining the role of cooperation in early tumor progression. J Theor Biol 2011; 285:36-45. [PMID: 21745479 DOI: 10.1016/j.jtbi.2011.06.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 05/30/2011] [Accepted: 06/27/2011] [Indexed: 12/14/2022]
Abstract
Competition among cells has long been recognized as an important part of carcinogenesis. However, the role of cellular cooperation in cancer has been largely ignored. In this work, we investigated the role of cooperation in early tumor progression using a mathematical and agent-based modeling approach. We hoped to learn how the introduction of cooperative cells into a cell population would affect the dynamics of the system. We modeled the stem cell compartment of tissue using a spatial structure organized into cell patches, with stem cells able to replicate or leave the stem cell compartment through apoptosis or differentiation. The cells could also acquire mutations in three oncogenes and two tumor suppressor genes. Cooperative cells in our model provided a cooperative signal that increased the fitness of their immediate neighbors, but did not affect their own fitness. Running simulations of the model, we found that if cooperative cells are introduced into a cell population, they steadily proliferate and confer a growth advantage to the entire population. This leads us to conclude that providing a cooperative signal is likely to be under positive selective pressure. When cooperative ability and mutation are concurrently present in the same cells, the overall cell population experiences a significant growth advantage, much greater than with cooperation or mutation alone. This growth advantage is diminished if cells with only oncogene/tumor suppressor mutations are also present in the population, suggesting that the optimal scenario for tumor growth would be for cooperative cells to take over a cell population, and then for mutations in oncogenes and tumor suppressors to arise on a background of cooperation. We predict that cooperation is particularly important in the very early stages of carcinogenesis, when tissue is morphologically and histologically normal. Our results have implications for the screening and early diagnosis of cancer.
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Affiliation(s)
- Konstantin Krepkin
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA.
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15
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Elyada E, Pribluda A, Goldstein RE, Morgenstern Y, Brachya G, Cojocaru G, Snir-Alkalay I, Burstain I, Haffner-Krausz R, Jung S, Wiener Z, Alitalo K, Oren M, Pikarsky E, Ben-Neriah Y. CKIα ablation highlights a critical role for p53 in invasiveness control. Nature 2011; 470:409-13. [PMID: 21331045 DOI: 10.1038/nature09673] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 11/17/2010] [Indexed: 12/11/2022]
Abstract
The mature gut renews continuously and rapidly throughout adult life, often in a damage-inflicting micro-environment. The major driving force for self-renewal of the intestinal epithelium is the Wnt-mediated signalling pathway, and Wnt signalling is frequently hyperactivated in colorectal cancer. Here we show that casein kinase Iα (CKIα), a component of the β-catenin-destruction complex, is a critical regulator of the Wnt signalling pathway. Inducing the ablation of Csnk1a1 (the gene encoding CKIα) in the gut triggers massive Wnt activation, surprisingly without causing tumorigenesis. CKIα-deficient epithelium shows many of the features of human colorectal tumours in addition to Wnt activation, in particular the induction of the DNA damage response and cellular senescence, both of which are thought to provide a barrier against malignant transformation. The epithelial DNA damage response in mice is accompanied by substantial activation of p53, suggesting that the p53 pathway may counteract the pro-tumorigenic effects of Wnt hyperactivation. Notably, the transition from benign adenomas to invasive colorectal cancer in humans is typically linked to p53 inactivation, underscoring the importance of p53 as a safeguard against malignant progression; however, the mechanism of p53-mediated tumour suppression is unknown. We show that the maintenance of intestinal homeostasis in CKIα-deficient gut requires p53-mediated growth control, because the combined ablation of Csnk1a1 and either p53 or its target gene p21 (also known as Waf1, Cip1, Sdi1 and Cdkn1a) triggered high-grade dysplasia with extensive proliferation. Unexpectedly, these ablations also induced non-proliferating cells to invade the villous lamina propria rapidly, producing invasive carcinomas throughout the small bowel. Furthermore, in p53-deficient gut, loss of heterozygosity of the gene encoding CKIα caused a highly invasive carcinoma, indicating that CKIα functions as a tumour suppressor when p53 is inactivated. We identified a set of genes (the p53-suppressed invasiveness signature, PSIS) that is activated by the loss of both p53 and CKIα and which probably accounts for the brisk induction of invasiveness. PSIS transcription and tumour invasion were suppressed by p21, independently of cell cycle control. Restraining tissue invasion through suppressing PSIS expression is thus a novel tumour-suppressor function of wild-type p53.
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Affiliation(s)
- Ela Elyada
- The Lautenberg Center for Immunology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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16
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MacFarlane AJ, Perry CA, McEntee MF, Lin DM, Stover PJ. Mthfd1 is a modifier of chemically induced intestinal carcinogenesis. Carcinogenesis 2011; 32:427-33. [PMID: 21156972 PMCID: PMC3047240 DOI: 10.1093/carcin/bgq270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 11/22/2010] [Accepted: 12/08/2010] [Indexed: 01/09/2023] Open
Abstract
The causal metabolic pathways underlying associations between folate and risk for colorectal cancer (CRC) have yet to be established. Folate-mediated one-carbon metabolism is required for the de novo synthesis of purines, thymidylate and methionine. Methionine is converted to S-adenosylmethionine (AdoMet), the major one-carbon donor for cellular methylation reactions. Impairments in folate metabolism can modify DNA synthesis, genomic stability and gene expression, characteristics associated with tumorigenesis. The Mthfd1 gene product, C1-tetrahydrofolate synthase, is a trifunctional enzyme that generates one-carbon substituted tetrahydrofolate cofactors for one-carbon metabolism. In this study, we use Mthfd1(gt/+) mice, which demonstrate a 50% reduction in C1-tetrahydrofolate synthase, to determine its influence on tumor development in two mouse models of intestinal cancer, crosses between Mthfd1(gt/+) and Apc(min)(/+) mice and azoxymethane (AOM)-induced colon cancer in Mthfd1(gt/+) mice. Mthfd1 hemizygosity did not affect colon tumor incidence, number or load in Apc(min/+) mice. However, Mthfd1 deficiency increased tumor incidence 2.5-fold, tumor number 3.5-fold and tumor load 2-fold in AOM-treated mice. DNA uracil content in the colon was lower in Mthfd1(gt/+) mice, indicating that thymidylate biosynthesis capacity does not play a significant role in AOM-induced colon tumorigenesis. Mthfd1 deficiency-modified cellular methylation potential, as indicated by the AdoMet: S-adenosylhomocysteine ratio and gene expression profiles, suggesting that changes in the transcriptome and/or decreased de novo purine biosynthesis and associated mutability cause cellular transformation in the AOM CRC model. This study emphasizes the impact and complexity of gene-nutrient interactions with respect to the relationships among folate metabolism and colon cancer initiation and progression.
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Affiliation(s)
- Amanda J. MacFarlane
- Present address: Nutrition Research Division, Health Canada, 251 Sir Frederick Banting Drive, Ottawa, Ontario K1Y 0K9, Canada
| | | | - Michael F. McEntee
- Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, 2407 River Drive, Knoxville, TN 37996, USA
| | - David M. Lin
- Department of Biomedical Sciences, Cornell University, T2-006A Veterinary Research Tower, Ithaca, NY 14853, USA
| | - Patrick J. Stover
- To whom correspondence should be addressed. Tel: +1 607 255 8001; Fax: +1 607 255 2698;
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17
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Zeilstra J, Joosten SP, Wensveen FM, Dessing MC, Schütze DM, Eldering E, Spaargaren M, Pals ST. WNT signaling controls expression of pro-apoptotic BOK and BAX in intestinal cancer. Biochem Biophys Res Commun 2011; 406:1-6. [DOI: 10.1016/j.bbrc.2010.12.070] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 01/30/2023]
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18
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Wip1, an oncogene targeting tumor suppressors expressed in intestinal stem cells. CURRENT COLORECTAL CANCER REPORTS 2009. [DOI: 10.1007/s11888-009-0027-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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19
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Abstract
Defective apoptosis contributes to tumorigenesis, although the critical molecular targets remain to be fully characterized. PUMA, a BH3-only protein essential for p53-dependent apoptosis, has been shown to suppress lymphomagenesis. In this study, we investigated the role of PUMA in intestinal tumorigenesis using two animal models. In the azoxymethane (AOM)/dextran sulfate sodium salt model, PUMA deficiency increased the multiplicity and size of colon tumors but reduced the frequency of beta-catenin hotspot mutations. The absence of PUMA led to a significantly elevated incidence of precursor lesions induced by AOM. AOM was found to induce p53-dependent PUMA expression and PUMA-dependent apoptosis in the colonic crypts and stem cell compartment. Furthermore, PUMA deficiency significantly enhanced the formation of spontaneous macroadenomas and microadenomas in the distal small intestine and colon of APC(Min/+) mice. These results show an essential role of PUMA-mediated apoptosis in suppressing intestinal tumorigenesis in mice.
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Affiliation(s)
- Wei Qiu
- Department of Pathology, University of Pittsburgh and Cancer Institute, Pittsburgh, Pennsylvania, USA
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20
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Apoptosis and colorectal cancer: implications for therapy. Trends Mol Med 2009; 15:225-33. [PMID: 19362056 DOI: 10.1016/j.molmed.2009.03.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 03/09/2009] [Accepted: 03/09/2009] [Indexed: 12/26/2022]
Abstract
Colorectal cancer (CRC) is characterized by the partial suppression of apoptosis, which in turn gives tumours a selective advantage for survival and can cause current chemotherapy approaches to be ineffective. Recent progress in understanding the mechanisms of apoptosis in colorectal carcinogenesis has provided potential new targets for therapy. Here, we review recent studies of the regulation of apoptosis and its role in CRC initiation and progression, and we discuss the relationship between chemoresistance and the suppression of apoptosis. Recent progress in targeting apoptotic pathways and their regulators provide strategies for the exploration of novel therapies for CRC.
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Garin-Laflam MP, Steinbrecher KA, Rudolph JA, Mao J, Cohen MB. Activation of guanylate cyclase C signaling pathway protects intestinal epithelial cells from acute radiation-induced apoptosis. Am J Physiol Gastrointest Liver Physiol 2009; 296:G740-9. [PMID: 19221018 PMCID: PMC2670662 DOI: 10.1152/ajpgi.90268.2008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Uroguanylin (UGN) is a peptide hormone that binds to and activates the intestinal epithelial cell (IEC) transmembrane receptor guanylate cyclase C (GC-C), which in turn increases intracellular cGMP. Gene targeting of murine UGN or GC-C results in significantly lower levels of cGMP in IECs. On the basis of effects of cGMP in nonintestinal systems, we hypothesized that loss of GC-C activation would increase intestinal epithelial apoptosis following radiation-induced injury. We first compared apoptosis from the proximal jejunum of C57BL/6 wild-type (WT) and GC-C knockout (KO) mice 3 h after they received 5 Gy of gamma-irradiation. We then investigated whether supplementation via intraperitoneal injection of 1 mM 8BrcGMP would mitigate radiation-induced apoptosis in these experimental animals. Identical experiments were performed in BALB/c UGN WT and KO mice. Apoptosis was assessed by quantitating morphological indications of cell death, terminal dUTP nick-end labeling, and cleaved caspase 3 immunohistochemistry. Both UGN KO and GC-C KO mice were more susceptible than their WT littermates in this in vivo model of apoptotic injury. Furthermore, cGMP supplementation in both GC-C and UGN KO animals ameliorated radiation-induced apoptosis. Neither WT strain demonstrated significant alteration in apoptotic susceptibility as a result of cGMP supplementation before radiation injury. These in vivo findings demonstrate increased radiosensitivity of IECs in UGN and GC-C KO mice and a role for cGMP as a primary downstream mediator of GC-C activation in the protection of these IECs from radiation-induced apoptosis.
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Affiliation(s)
- M. P. Garin-Laflam
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - K. A. Steinbrecher
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - J. A. Rudolph
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - J. Mao
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
| | - M. B. Cohen
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, and the University of Cincinnati, Cincinnati, Ohio
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22
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Nie B, Shen Z, Wen JB, Wong OGW, Hsueh WD, Huo LF, Kung HF, Jiang B, Lin MCM. AAV-HGFK1 and Ad-p53 cocktail therapy prolongs survival of mice with colon cancer. Mol Cancer Ther 2008; 7:2855-65. [PMID: 18790766 DOI: 10.1158/1535-7163.mct-08-0366] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study tried to evaluate the application of a novel cancer gene therapy using recombinant adeno-associated virus (AAV) carrying the kringle 1 domain of human hepatocyte growth factor (AAV-HGFK1) in combination with recombinant adenovirus carrying p53 gene (Ad-p53). BALB/c and nude mice models of colon cancer were established and the mice were treated with AAV-HGFK1 alone or in combination with Ad-p53. Combination of AAV-HGFK1 and Ad-p53 significantly prolonged the survival of the mice and also significantly inhibited primary and secondary tumor growth. Histochemical examination of the tumors revealed that AAV-HGFK1+Ad-p53 combinatorial treatment not only induced necrosis and apoptosis in the tumors but also suppressed tumor angiogenesis. The antiangiogenesis effect could likely be attributed to the ability of AAV-HGFK1+Ad-p53 viral cocktail to inhibit endothelial cell migration and proliferation. AAV-HGFK1+Ad-p53 also inhibited tumor cell growth in vitro by inhibiting epidermal growth factor receptor phosphorylation. Therefore, AAV-HGFK1+Ad-p53 cocktail therapy has a significantly higher therapeutic effect than AAV-HGFK1 or Ad-p53 alone and is a novel promising gene therapy for colon cancer.
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Affiliation(s)
- Biao Nie
- Institute for Digestive Medicine and Department of Gastroenterology, Nanfang Hospital, Nanfang Medical University, Guangzhou, Republic of China
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23
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Reed KR, Meniel VS, Marsh V, Cole A, Sansom OJ, Clarke AR. A limited role for p53 in modulating the immediate phenotype of Apc loss in the intestine. BMC Cancer 2008; 8:162. [PMID: 18533991 PMCID: PMC2443808 DOI: 10.1186/1471-2407-8-162] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Accepted: 06/05/2008] [Indexed: 11/18/2022] Open
Abstract
Background p53 is an important tumour suppressor with a known role in the later stages of colorectal cancer, but its relevance to the early stages of neoplastic initiation remains somewhat unclear. Although p53-dependent regulation of Wnt signalling activity is known to occur, the importance of these regulatory mechanisms during the early stages of intestinal neoplasia has not been demonstrated. Methods We have conditionally deleted the Adenomatous Polyposis coli gene (Apc) from the adult murine intestine in wild type and p53 deficient environments and subsequently compared the phenotype and transcriptome profiles in both genotypes. Results Expression of p53 was shown to be elevated following the conditional deletion of Apc in the adult small intestine. Furthermore, p53 status was shown to impact on the transcription profile observed following Apc loss. A number of key Wnt pathway components and targets were altered in the p53 deficient environment. However, the aberrant phenotype observed following loss of Apc (rapid nuclear localisation of β-catenin, increased levels of DNA damage, nuclear atypia, perturbed cell death, proliferation, differentiation and migration) was not significantly altered by the absence of p53. Conclusion p53 related feedback mechanisms regulating Wnt signalling activity are present in the intestine, and become activated following loss of Apc. However, the physiological Wnt pathway regulation by p53 appears to be overwhelmed by Apc loss and consequently the activity of these regulatory mechanisms is not sufficient to modulate the immediate phenotypes seen following Apc loss. Thus we are able to provide an explanation to the apparent contradiction that, despite having a Wnt regulatory capacity, p53 loss is not associated with early lesion development.
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Affiliation(s)
- Karen R Reed
- Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3US, UK.
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24
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Huerta S, Goulet EJ, Livingston EH. Colon cancer and apoptosis. Am J Surg 2006; 191:517-26. [PMID: 16531147 DOI: 10.1016/j.amjsurg.2005.11.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 11/28/2005] [Accepted: 11/28/2005] [Indexed: 02/06/2023]
Abstract
BACKGROUND The implementation of new therapeutic options for the management of metastatic colon cancer mandates a revisit to apoptosis and its role in colon cancer tumorigenesis with an emphasis on the mechanisms leading to chemotherapeutic resistance and immune system evasion of colon cancer cells. DATA SOURCES Literature regarding molecular apoptosis mechanisms and the role of apoptosis in colon cancer progression are reviewed by this article. CONCLUSION Programmed cell death has rapidly emerged as a potential target for cancer treatment at various stages of tumor progression. Chemoprevention, immuno-regulation, and metastasis are prospective targets by which apoptotic mechanisms could be utilized in the prevention and management of tumorigenesis. Understanding how defects in the death receptor pathway of apoptosis permit colon cancer cells to escape the immune system would allow for treatment options whereby the body's immune system could again recognize and eliminate unwanted cells.
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Affiliation(s)
- Sergio Huerta
- Department of Gastrointestinal and Endocrine Surgery, University of Texas Southwestern Medical Center/Veterans Administration North Texas Health Care System, Dallas, TX 75216, USA.
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25
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Fenton JI, Hord NG. Stage matters: choosing relevant model systems to address hypotheses in diet and cancer chemoprevention research. Carcinogenesis 2006; 27:893-902. [PMID: 16474168 DOI: 10.1093/carcin/bgi355] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Clinical evidence reveals that the efficacy of dietary factors to prevent cancer is probably stage-dependent. The ability to demonstrate stage-specific effects of dietary compounds on normal, preneoplastic and malignant cell models may provide insights into puzzling clinical results from cancer chemoprevention trials. The relevance of these models to the field of cancer prevention is immense and will undoubtedly facilitate the ability to discover which dietary factors are most effective at preventing cancer and which, if any, specific steps in neoplastic transformation render cells refractory to the effects of dietary compounds. There are illustrative examples where exposure of high-risk individuals to dietary chemopreventive agents increases rather than decreases cancer risk. While geneticists and clinical oncologists acknowledge the morphological continuum along which tumors develop in specific tissues, tumor cells, rather than normal and preneoplastic cells, continue to be the primary in vitro reductionist tool employed to elucidate mechanisms underlying disease progression and to investigate the potential utility of dietary as well as other chemopreventive agents. Currently, there are few relevant model systems to study the progression of neoplastic transformation, especially in epithelial cells. We highlight examples of model systems isolated from prostate, breast, endometrial and intestinal tissue, with special emphasis on a specific set of non-tumorigenic, conditionally immortal cell lines derived from C57/BL6 mice [YAMC (Young Adult Mouse Colon cells; Apc+/+) cells and IMCE (Immorto-Min Colonic Epithelium cells; ApcMin/+) cells] that have yielded important information on early events in colorectal neoplasia development. These cell lines are an illustrative example of how researchers can examine stage-dependent effects of specific dietary components on carcinogenesis. The utilization of cell culture systems modeling early, middle and late stages of tumorigenesis will yield important insights into mechanisms by which dietary components impact cancer progression.
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Affiliation(s)
- Jenifer I Fenton
- Cancer Prevention Fellowship Program, Division of Cancer Prevention, National Cancer Institute, Bethesda, MD 20892-7361, USA.
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26
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Wilson JM, Coletta PL, Cuthbert RJ, Scott N, MacLennan K, Hawcroft G, Leng L, Lubetsky JB, Jin KK, Lolis E, Medina F, Brieva JA, Poulsom R, Markham AF, Bucala R, Hull MA. Macrophage migration inhibitory factor promotes intestinal tumorigenesis. Gastroenterology 2005; 129:1485-503. [PMID: 16285950 DOI: 10.1053/j.gastro.2005.07.061] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Accepted: 07/21/2005] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS The cytokine macrophage migration inhibitory factor (MIF) is expressed throughout the human gastrointestinal tract. Recently, protumorigenic activity of MIF has been described in several cancer models. Therefore, we investigated the expression and function of MIF during the early stages of intestinal tumorigenesis. METHODS MIF messenger RNA, protein, and tautomerase activity were measured in normal intestinal mucosa and adenomas from patients with sporadic colorectal adenomas and in the adenomatous polyposis coli (Apc)Min/+ mouse model of intestinal tumorigenesis. MIF function was investigated by using VACO-235 human colorectal adenoma cells in vitro and by testing the effect of genetic deletion of Mif on ApcMin/+ mouse intestinal tumorigenesis. RESULTS MIF expression and tautomerase activity were increased in human and ApcMin/+ mouse intestinal adenomas compared with adjacent normal mucosa. Up-regulation of MIF occurred mainly in epithelial cells (associated with an increasing grade of dysplasia), but also in stromal plasma cells. Exogenous MIF inhibited apoptosis and promoted anchorage-independent growth of VACO-235 cells (maximal at 100 ng/mL). Homozygous deletion of Mif was associated with a reduction in the number and size of ApcMin/+ mouse adenomas (P = .025 for the difference in large [>7-mm] tumors) and decreased angiogenesis (43% decrease in mean tumor microvessel density), but there was no alteration in epithelial cell apoptosis or proliferation. CONCLUSIONS MIF expression is increased in sporadic human colorectal adenomas, and exogenous MIF drives tumorigenic behavior of epithelial cells in vitro. Mif also promotes intestinal tumorigenesis (predominantly via angiogenesis) in the ApcMin/+ mouse. Therefore, MIF is a potential colorectal cancer chemoprevention target.
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Pool-Zobel BL. Inulin-type fructans and reduction in colon cancer risk: review of experimental and human data. Br J Nutr 2005; 93 Suppl 1:S73-90. [PMID: 15877900 DOI: 10.1079/bjn20041349] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Inulin-type fructans (beta(2,1)fructans) extracted from chicory roots (Cichorium intybus) are prebiotic food ingredients, which in the gut lumen are fermented to lactic acid and SCFA. Research in experimental animal models revealed that inulin-type fructans have anticarcinogenic properties. A number of studies report the effects of inulin-type fructans on chemically induced pre-neoplastic lesions (ACF) or tumours in the colon of rats and mice. In twelve studies, there were twenty-nine individual treatment groups of which twenty-four measured aberrant crypt foci (ACF) and five measured tumours. There was a significant reduction of ACF in twenty-one of the twenty-four treatment groups and of tumour incidence in five of the five treatment groups. Higher beneficial effects were achieved by synbiotics (mixtures of probiotics and prebiotics), long-chain inulin-type fructans compared to short-chain derivatives, and feeding high-fat Western style diets. Inulin-type fructans reduced tumour incidence in APC(Min) mice in two of four studies and reduced growth and metastasising properties of implanted tumour cells in mice (four studies). The effects have been reported to be associated with gut flora-mediated fermentation and production of butyrate. In human cells, inulin-derived fermentation products inhibited cell growth, modulated differentiation and reduced metastasis activities. In conclusion, evidence has been accumulated that shows that inulin-type fructans and corresponding fermentation products reduced the risks for colon cancer. The involved mechanisms included the reduction of exposure to risk factors and suppression of tumour cell survival. Thus, this specific type of dietary fibre exerted both blocking agent and suppressing agent types of chemopreventive activities.
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Affiliation(s)
- Beatrice L Pool-Zobel
- Department of Nutritional Toxicology, Institute for Nutritional Sciences, Friedrich-Schiller-University Jena, Germany.
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Yang Y, Ludwig RL, Jensen JP, Pierre SA, Medaglia MV, Davydov IV, Safiran YJ, Oberoi P, Kenten JH, Phillips AC, Weissman AM, Vousden KH. Small molecule inhibitors of HDM2 ubiquitin ligase activity stabilize and activate p53 in cells. Cancer Cell 2005; 7:547-59. [PMID: 15950904 DOI: 10.1016/j.ccr.2005.04.029] [Citation(s) in RCA: 246] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Revised: 03/02/2005] [Accepted: 04/21/2005] [Indexed: 12/13/2022]
Abstract
The p53 tumor suppressor protein is regulated by its interaction with HDM2, which serves as a ubiquitin ligase (E3) to target p53 for degradation. We have identified a family of small molecules (HLI98) that inhibits HDM2's E3 activity. These compounds show some specificity for HDM2 in vitro, although at higher concentrations effects on unrelated RING and HECT domain E3s are detectable, which could be due, at least in part, to effects on E2-ubiquitin thiol-ester levels. In cells, the compounds allow the stabilization of p53 and HDM2 and activation of p53-dependent transcription and apoptosis, although other p53-independent toxicity was also observed.
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Affiliation(s)
- Yili Yang
- Laboratory of Protein Dynamics and Signaling, Center for Cancer Research, National Cancer Institute at Frederick, NIH, 1050 Boyles Street, Frederick, MD 21702, USA
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Abstract
Colon cancer is the third most common cancer globally. The risk of developing colon cancer is influenced by a number of factors that include age and diet, but is primarily a genetic disease, resulting from oncogene over-expression and tumour suppressor gene inactivation. The induction and progression of the disease is briefly outlined, as are the cellular changes that occur in its progression. While colon cancer is uniformly amenable to surgery if detected at the early stages, advanced carcinomas are usually lethal, with metastases to the liver being the most common cause of death. Oncogenes and genetic mutations that occur in colon cancer are featured. The molecules and signals that act to eradicate or initiate the apoptosis cascade in cancer cells, are elucidated, and these include caspases, Fas, Bax, Bid, APC, antisense hTERT, PUMA, 15-LOX-1, ceramide, butyrate, tributyrin and PPARgamma, whereas the molecules which promote colon cancer cell survival are p53 mutants, Bcl-2, Neu3 and COX-2. Cancer therapies aimed at controlling colon cancer are reviewed briefly.
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Affiliation(s)
- Charleen Rupnarain
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa
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30
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Esaki M, Matsumoto T, Yao S, Nakamura S, Hirahashi M, Yao T, Iida M. Immunohistochemical characteristics of duodenal adenomas in familial adenomatous polyposis with special reference to cell kinetics. Hum Pathol 2005; 36:66-73. [PMID: 15712184 DOI: 10.1016/j.humpath.2004.10.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The duodenum is the second most frequent site of cancer in patients with familial adenomatous polyposis (FAP). The main objective of this study was to evaluate the cell kinetics in duodenal and ampullary adenomas in FAP. The endoscopic and biopsy findings of duodenal adenomas in 22 FAP subjects and 18 non-FAP subjects were compared. Adenomas in FAP included 15 ampullary adenomas and 17 nonampullary adenomas. The cell kinetics was evaluated by immunohistochemistry for Ki-67, p53, bcl-2, and cyclooxygenase 2 (COX2), and the apoptotic index (AI) as determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) method. Any correlations between the indices for cell kinetics and the endoscopic findings were identified. All 50 adenomas were histologically verified to be tubular adenoma with low-grade dysplasia. Neither the expression of Ki-67, p53, bcl-2, and COX2 nor the AI differed substantially between FAP and non-FAP subjects. In patients with FAP, duodenal adenoma tended to have a higher Ki-67-labeling index than the ampullary adenoma (54.3 +/- 11.3 versus 46.8 +/- 12.7; .05 < P < .1). In addition, the Ki-67-labeling index in endoscopically normal or slightly enlarged ampullary adenoma was significantly higher than that in markedly enlarged ampullary adenoma (51.8 +/- 11.4 versus 39.4 +/- 11.3; P < .05). Duodenal adenoma in FAP subjects was not found to have a higher proliferative activity or a smaller degree of apoptosis compared with those in non-FAP subjects. The smaller proliferative activity in larger ampullary adenoma may thus be related to the static nature of ampullary adenoma in FAP.
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Affiliation(s)
- Motohiro Esaki
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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31
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Mehlen P, Fearon ER. Role of the dependence receptor DCC in colorectal cancer pathogenesis. J Clin Oncol 2004; 22:3420-8. [PMID: 15310786 DOI: 10.1200/jco.2004.02.019] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
More than a decade ago, the DCC (deleted in colorectal cancer) gene was proposed as a putative tumor suppressor gene. Data supporting this proposal included observations that one DCC allele was deleted in roughly 70% of colorectal cancers, some cancers had somatic mutations of the DCC gene, and DCC expression was often reduced or absent in colorectal cancer tissues and cell lines. Despite subsequent studies which have supported DCC's potential role as a tumor suppressor gene, the rarity of point mutations identified in DCC coding sequences, the lack of a tumor predisposition phenotype in mice heterozygous for DCC inactivating mutations, and the presence of other known and candidate tumor suppressor genes on chromosome 18q have raised questions about DCC's candidacy. Following its initial characterization, the DCC protein was identified as a transmembrane receptor for netrins, key factors in axon guidance in the developing nervous system. At first glance, the established role of DCC and netrin-1 during organization of the spinal cord could be viewed as a further challenge to the position that DCC inactivation might play a significant role in tumorigenesis. However, recent observations on DCC's functions in intracellular signaling have renewed interest in the potential contribution of DCC inactivation to cancer. In particular, data indicate that, when engaged by netrin ligands, DCC may activate downstream signaling pathways. Moreover, in settings where netrin is absent or at low levels, DCC can promote apoptosis. Here, we review DCC's candidacy as a tumor suppressor gene, with an emphasis on how recent molecular analyses of DCC have offered support for the notion that DCC may function as a tumor suppressor gene.
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Affiliation(s)
- Patrick Mehlen
- Apoptosis/Differentiation Laboratory Equipe labelisée La Ligue Molecular and Cellular Genetic Center, CNRS UMR 5534, University of Lyon, 69622 Villeurbanne, France.
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32
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Nitta Y, Yoshida K, Satoh K, Senba K, Nakagata N, Peters J, Cattanach BM. Spontaneous and radiation-induced leukemogenesis of the mouse small eye mutant, Pax6(Sey3H). JOURNAL OF RADIATION RESEARCH 2004; 45:245-251. [PMID: 15304967 DOI: 10.1269/jrr.45.245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Allelic loss on the chromosome 2 is associated with radiation-induced murine acute myeloid leukemia. However, the gene, which contributes mainly to the leukemogenesis has not yet been identified. Expecting any predisposition to acute myeloid leukemia, we performed a radiation leukemogenensis experiment with Pax6(Sey3H), one of the small eye mutants carrying a congenital hemizygosity of the chromosome 2 middle region. A deletion mapping of Pax6(Sey3H) with 50 STS markers indicated that the deleted segment extended between the 106.00 and 111.47 Mb site from the centromere with a length of 5.47 Mb. In the deleted segment, 6 known and 17 novel genes were located. Pax6(Sey3H) mutants that crossed back into C3H/He did not develop myeloid leukemia spontaneously, but they did when exposed to gamma-rays. The final incidence of myeloid leukemia in mutants (25.8%) was as high as that in normal sibs (21.4%). Survival curves of leukemia-bearing mutants shifted toward the left (p = 0.043 by the Log rank test). F1 hybrids of Pax6(Sey3H) with JF1 were less susceptible to radiation than Pax6(Sey3H) onto C3H/He in regard to survival (p = 0.003 and p < 0.00001 for mutants and normal sibs, respectively, by a test of the difference between two proportions). Congenital deletion of the 5.47 Mb segment at the middle region on chromosome 2 alone did not trigger myeloid stem cells to expand clonally in vivo; however, the deletion shortcut the latency of radiation-induced myeloid leukemia.
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Affiliation(s)
- Yumiko Nitta
- International Radiation Information Center, Research Institute for Radiation Biology and Medicine, Hiroshima University, Japan.
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33
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Nitta Y, Yoshida K, Nakagata N, Harada T, Ishizaki F, Nitta K, Torii M. Effects of a Hemizygous Deletion of Mouse Chromosome 2 on the Hematopoietic and Intestinal Tumorigenesis. J Toxicol Pathol 2004. [DOI: 10.1293/tox.17.105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Yumiko Nitta
- International Radiation Information Center, Research Institute for Radiation Biology and Medicine, Hiroshima University
| | - Kazuko Yoshida
- Environmental and Toxicological Sciences Research Group, National Institute for Radiological Science
| | - Naomi Nakagata
- Division of Reproductive Engineering, Institute of Resource Development and Analysis, Kumamoto University
| | - Toshihide Harada
- Third department of Internal Medicine, School of Medicine, Hiroshima University
| | | | | | - Mikinori Torii
- Developmental of Research Laboratories, Shionogi Co. Ltd
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34
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Corpet DE, Pierre F. Point: From animal models to prevention of colon cancer. Systematic review of chemoprevention in min mice and choice of the model system. Cancer Epidemiol Biomarkers Prev 2003; 12:391-400. [PMID: 12750232 PMCID: PMC2797538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
The Apc(Min/+) mouse model and the azoxymethane (AOM) rat model are the main animal models used to study the effect of dietary agents on colorectal cancer. We reviewed recently the potency of chemopreventive agents in the AOM rat model (D. E. Corpet and S. Tache, Nutr. Cancer, 43: 1-21, 2002). Here we add the results of a systematic review of the effect of dietary and chemopreventive agents on the tumor yield in Min mice. The review is based on the results of 179 studies from 71 articles and is displayed also on the internet http://corpet.net/min.(2) We compared the efficacy of agents in the Min mouse model and the AOM rat model, and found that they were correlated (r = 0.66; P < 0.001), although some agents that afford strong protection in the AOM rat and the Min mouse small bowel increase the tumor yield in the large bowel of mutant mice. The agents included piroxicam, sulindac, celecoxib, difluoromethylornithine, and polyethylene glycol. The reason for this discrepancy is not known. We also compare the results of rodent studies with those of clinical intervention studies of polyp recurrence. We found that the effect of most of the agents tested was consistent across the animal and clinical models. Our point is thus: rodent models can provide guidance in the selection of prevention approaches to human colon cancer, in particular they suggest that polyethylene glycol, hesperidin, protease inhibitor, sphingomyelin, physical exercise, epidermal growth factor receptor kinase inhibitor, (+)-catechin, resveratrol, fish oil, curcumin, caffeate, and thiosulfonate are likely important preventive agents.
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Affiliation(s)
- Denis E Corpet
- UMR Xenobiotiques, Institut National Recherche Agronomique, Ecole Nationale Veterinaire Toulouse, 31076 Toulouse, France.
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35
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Abstract
The p53 tumor-suppressor plays a critical role in the prevention of human cancer. In the absence of cellular stress, the p53 protein is maintained at low steady-state levels and exerts very little, if any, effect on cell fate. However, in response to various types of stress, p53 becomes activated; this is reflected in elevated protein levels, as well as augmented biochemical capabilities. As a consequence of p53 activation, cells can undergo marked phenotypic changes, ranging from increased DNA repair to senescence and apoptosis. This review deals with the mechanisms that underlie the apoptotic activities of p53, as well as the complex interactions between p53 and central regulatory signaling networks. In p53-mediated apoptosis, the major role is played by the ability of p53 to transactivate specific target genes. The choice of particular subsets of target genes, dictated by covalent p53 modifications and protein-protein interactions, can make the difference between life and apoptotic death of a cell. In addition, transcriptional repression of antiapoptotic genes, as well as transcription-independent activities of p53, can also contribute to the apoptotic effects of p53. Regarding the crosstalk between p53 and signaling networks, this review focuses on the interplay between p53 and two pivotal regulatory proteins: beta-catenin and Akt/PKB. Both proteins can regulate p53 as well as be regulated by it. In addition, p53 interacts with the GSK-3beta kinase, which serves as a link between Akt and beta-catenin. This review discusses how the functional balance between these different interactions might dictate the likelihood of a given cell to become cancerous or be eliminated from the replicative pool, resulting in suppression of cancer.
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Affiliation(s)
- M Oren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 76100, Israel
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36
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Koornstra JJ, de Jong S, Hollema H, de Vries EGE, Kleibeuker JH. Changes in apoptosis during the development of colorectal cancer: a systematic review of the literature. Crit Rev Oncol Hematol 2003; 45:37-53. [PMID: 12482571 DOI: 10.1016/s1040-8428(01)00228-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The development of colorectal cancer is characterised by an accumulation of molecular genetic alterations causing disorders in cell growth, differentiation and apoptosis. Although changes in apoptosis with colorectal cancer development have been studied extensively, a clear consensus of opinion has not yet emerged. In this review, the literature about changes in the frequency and distribution of apoptosis in tissue sections of normal and neoplastic colorectal tissues was reviewed systematically. Using a PUBMED search, 53 relevant articles were identified. Data from these studies are discussed with respect to the following aspects: methods used to detect apoptotic cell death; frequency and locoregional distribution of apoptosis in normal mucosa, adenomas and carcinomas; the correlation between levels of apoptosis and proliferation and the prognostic significance of the degree of apoptosis in colorectal cancer. Possible underlying mechanisms of dysregulation of apoptosis are discussed briefly. Finally, possible therapeutic implications of knowledge of the molecular regulation of apoptosis are discussed and potential options for further research are suggested.
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Affiliation(s)
- J J Koornstra
- Department of Medical Oncology, University Hospital, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
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37
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Bürgel N, Bojarski C, Mankertz J, Zeitz M, Fromm M, Schulzke JD. Mechanisms of diarrhea in collagenous colitis. Gastroenterology 2002; 123:433-43. [PMID: 12145796 DOI: 10.1053/gast.2002.34784] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS Collagenous colitis is an inflammatory disease of unknown etiology with diarrhea as the leading symptom. The aim of this study was to examine the pathogenic mechanisms of this disease. METHODS Biopsy specimens of the sigmoid colon were obtained endoscopically. Short-circuit current and (22)Na and (36)Cl fluxes were measured in miniaturized Ussing chambers. Alternating current impedance analysis discriminated epithelial from subepithelial resistance. Tight junction proteins occludin and claudin 1-5 were characterized in membrane fractions by Western blotting. Apoptotic ratio was determined by DAPI and TUNEL staining. RESULTS In collagenous colitis, net Na(+) flux decreased from 8.8 +/- 1.8 to 0.2 +/- 1.5 and net Cl(-) flux from 11.2 +/- 3.0 to -3.0 +/- 2.7 micromol x h(-1) x cm(-2), indicating a pronounced decrease in NaCl absorption. The fact that short-circuit current increased from 1.5 +/- 0.4 to 3.9 +/- 0.8 micromol x h(-1) x cm(-2), together with the negative net Cl(-) flux, points to activation of active electrogenic chloride secretion. Subepithelial resistance increased from 7 +/- 1 to 18 +/- 2 Omega x cm(2) due to subepithelial collagenous bands of 48 +/- 8-microm thickness. Epithelial resistance was diminished from 44 +/- 3 to 29 +/- 2 Omega x cm(2), and this was accompanied by a decrease in occludin and claudin-4 expression. Neither mucosal surface area nor apoptotic ratio was altered in collagenous colitis. CONCLUSIONS Reduced net Na(+) and Cl(-) absorption is the predominant diarrheal mechanism in collagenous colitis, accompanied by a secretory component of active electrogenic chloride secretion. The subepithelial collagenous band as a significant diffusion barrier is a cofactor. Down-regulation of tight junction molecules but not epithelial apoptoses is a structural correlate of barrier dysfunction contributing to diarrhea by a leak flux mechanism.
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Affiliation(s)
- Natalie Bürgel
- Department of Gastroenterology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Berlin, Germany
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38
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Bojarski C, Gitter AH, Bendfeldt K, Mankertz J, Schmitz H, Wagner S, Fromm M, Schulzke JD. Permeability of human HT-29/B6 colonic epithelium as a function of apoptosis. J Physiol 2001; 535:541-52. [PMID: 11533143 PMCID: PMC2278785 DOI: 10.1111/j.1469-7793.2001.00541.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
1. The barrier function of colonic epithelia is challenged by apoptotic loss of enterocytes. In monolayers of human colonic HT-29/B6 cells, apoptosis induced by camptothecin was assessed by poly-(ADP-ribose)-polymerase (PARP) cleavage, histone ELISA and DNA-specific fluorochrome staining (with 4',6'-diamidino-2'-phenylindoladihydrochloride (DAPI)). Epithelial barrier function was studied in Ussing chambers by measuring transepithelial conductivity and unidirectional tracer fluxes. The ion permeability associated with single cell apoptoses was investigated with the conductance scanning technique. 2. The spontaneous rate of apoptotic cells was 3.5 +/- 0.3 % with an overall epithelial conductivity of 3.2 +/- 0.1 mS cm(-2). Camptothecin induced a time- and dose-dependent increase of apoptosis and permeability. With 20 microg ml(-1) of camptothecin for 48 h, apoptosis increased 4.1-fold to 14.3 +/- 1.5 % and the conductivity doubled to 6.4 +/- 1.0 mS cm(-2). 3. While 3H-mannitol flux increased 3.8-fold and 3H-lactulose flux increased 2.6-fold, the flux of 3H-polyethylene glycol 4000 remained unchanged. Hence, the higher permeability was limited to molecules < 4000 Da. 4. The local epithelial conductivity was higher at the sites of apoptosis than in non-apoptotic areas. With camptothecin the leaks associated with apoptosis became more numerous and more conductive, while in non-apoptotic areas the conductivity remained at control level. Hence, the camptothecin-induced increase in epithelial conductivity reflected the opening of apoptotic leaks and thus the results described, for the first time, epithelial permeability as a function of apoptosis only. 5. The conductivity of apoptotic leaks contributed 5.5 % to the epithelial conductivity of controls and 60 % to the conductivity of monolayers treated with 20 microg ml(-1) of camptothecin. Thus apoptosis increased the contribution of paracellular pathways to the overall epithelial permeability. Under control conditions the paracellular conductivity (G(para)) was smaller than the transcellular (G(trans)), but with 12 % apoptosis, G(para) exceeded G(trans). By definition, the epithelium became 'leaky'.
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Affiliation(s)
- C Bojarski
- Department of Gastroenterology, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, 12200 Berlin, Germany
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Abstract
Mutations in the APC gene are responsible for familial adenomatous polyposis (FAP) and for the majority of sporadic colorectal cancers. The establishment of genotype-phenotype correlations in FAP is often complicated by the great clinical variability observed among carriers of the same APC mutation even within the same kindred. This variability is likely to arise from the interaction of genetic and environmental modifying factors, the dissection of which ideally requires the employment of mouse models where the effects of specific Apc mutations are analyzed in an inbred, homogeneous genetic background and a controlled environment. The availability of different Apc mouse models allows not only the establishment of more precise genotype-phenotype correlations but has also provided very important clues for the understanding of the function of APC in homeostasis and tumorigenesis. Also, the close phenotypic resemblance to the human disease makes these mice unique preclinical models to test chemopreventive and therapeutic interventions.
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Affiliation(s)
- R Fodde
- Dept. of Human and Clinical Genetics, Leiden University Medical Center, Sylvius Laboratories, Wassenaarseweg 72, 2333 AL, Leiden, The Netherlands.
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40
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Affiliation(s)
- A A Palejwala
- Department of Medicine, Royal Liverpool University Hospital, University of Liverpool, United Kingdom
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41
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Abstract
P53 is extremely well characterised as a tumour suppressor gene, and many activities have been attributed to it which are consistent with this function. However, despite being the subject of intense study it still remains unclear precisely which of these functions is crucial to its in vivo role as a tumour suppressor gene. This is particularly true of its role in the induction of apoptosis. The original observation of p53-dependent apoptosis gave rise to the following hypothesis: namely, that p53 deficiency leads to a persistence of DNA damaged cells which are the potential founders of malignancy. This review summarises the data for and against this hypothesis, with specific emphasis on data obtained from studies of the murine intestine. What emerges from these studies is a complex picture, where data can be obtained in support of this hypothesis, but there are many circumstances which exist where it is not supported. Taken together this collection of data suggests that the abrogation of p53-dependent apoptosis may indeed impact upon carcinogenesis and neoplastic progression, but that the simplistic notion of p53 as the single gatekeeper of this pathway is untenable.
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Affiliation(s)
- O J Sansom
- Department of Pathology, Medical School, Teviot Place, University of Edinburgh, EH8 9AG Edinburgh, UK
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42
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Shao C, Deng L, Henegariu O, Liang L, Stambrook PJ, Tischfield JA. Chromosome instability contributes to loss of heterozygosity in mice lacking p53. Proc Natl Acad Sci U S A 2000; 97:7405-10. [PMID: 10861008 PMCID: PMC16558 DOI: 10.1073/pnas.97.13.7405] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The p53 tumor suppressor protein participates in multiple cellular processes including cell cycle checkpoints and programmed cell death. In cell lines, loss of p53 function is associated with increased genetic instability including aneuploidy, gene amplification, and point mutation. Although similar genetic instability often accompanies the progression of malignancy in tumors, its role in tumor initiation in normal cells is not clear. To study whether or not loss of p53 leads to genetic instability in normal cells in vivo, we have examined mechanisms of loss of heterozygosity (LOH) at the Aprt (adenine phosphoribsyltransferase) and flanking loci in normal fibroblasts and T lymphocytes of p53-deficient mice. Somatic cell variants that arose in vivo as a consequence of genetic or epigenetic alterations abolishing Aprt function were selected and expanded in vitro by virtue of their resistance to 2,6-diaminopurine (DAP). We observed that p53 null mice produced about three times as many DAP-resistant fibroblast colonies than wild-type mice, but the frequency of DAP-resistant T lymphocyte colonies was not significantly changed. Mitotic recombination, but not point mutation, partly accounted for the increase in the frequency of DAP-resistant fibroblasts. Most significantly, chromosome loss/duplication and interstitial deletion, which were extremely rare events in the wild-type mice, represented a significant proportion of LOH events in both fibroblasts and T lymphocytes of p53 null mice. Also, increased interstitial deletion was observed in fibroblasts of p53 heterozygous mice. These data suggest that increased genetic variation, including chromosome instability, starts at the initiation stage of tumorigenesis when functional p53 is absent or reduced.
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Affiliation(s)
- C Shao
- Department of Genetics, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ 08854-8082, USA
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43
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Tumorigenesis in the multiple intestinal neoplasia mouse: redundancy of negative regulators and specificity of modifiers. Proc Natl Acad Sci U S A 2000; 97. [PMID: 10716720 PMCID: PMC16262 DOI: 10.1073/pnas.050585597] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The interaction between mutations in the tumor-suppressor genes Apc and p53 was studied in congenic mouse strains to minimize the influence of polymorphic modifiers. The multiplicity and invasiveness of intestinal adenomas of Apc(Min/+) (Min) mice was enhanced by deficiency for p53. In addition, the occurrence of desmoid fibromas was strongly enhanced by p53 deficiency. The genetic modifier Mom1 and the pharmacological agents piroxicam and difluoromethylornithine each reduced intestinal adenoma multiplicity in the absence of p53 function. Mom1 showed no influence on the development of desmoid fibromas, whereas the combination of piroxicam and difluoromethylornithine exerted a moderate effect. The ensemble of tumor suppressors and modifiers of a neoplastic process can be usefully analyzed in respect to tissue specificity and synergy.
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44
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Halberg RB, Katzung DS, Hoff PD, Moser AR, Cole CE, Lubet RA, Donehower LA, Jacoby RF, Dove WF. Tumorigenesis in the multiple intestinal neoplasia mouse: Redundancy of negative regulators and specificity of modifiers. Proc Natl Acad Sci U S A 2000; 97:3461-6. [PMID: 10716720 PMCID: PMC16262 DOI: 10.1073/pnas.97.7.3461] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The interaction between mutations in the tumor-suppressor genes Apc and p53 was studied in congenic mouse strains to minimize the influence of polymorphic modifiers. The multiplicity and invasiveness of intestinal adenomas of Apc(Min/+) (Min) mice was enhanced by deficiency for p53. In addition, the occurrence of desmoid fibromas was strongly enhanced by p53 deficiency. The genetic modifier Mom1 and the pharmacological agents piroxicam and difluoromethylornithine each reduced intestinal adenoma multiplicity in the absence of p53 function. Mom1 showed no influence on the development of desmoid fibromas, whereas the combination of piroxicam and difluoromethylornithine exerted a moderate effect. The ensemble of tumor suppressors and modifiers of a neoplastic process can be usefully analyzed in respect to tissue specificity and synergy.
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Affiliation(s)
- R B Halberg
- McArdle Laboratory for Cancer Research, Department of Biostatistics, University of Wisconsin, Madison, WI 53706, USA
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45
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Chapkin RS, Lupton JR. Colonic cell proliferation and apoptosis in rodent species. Modulation by diet. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 470:105-18. [PMID: 10709680 DOI: 10.1007/978-1-4615-4149-3_12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- R S Chapkin
- Faculty of Nutrition, Molecular and Cell Biology Group Texas A&M University, College Station 77843-2471, USA
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46
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Abstract
The APC protein is a crucial regulator of intestinal cell growth, and mutations in the APC gene are a common initial event in the process of human colorectal carcinogenesis. Animals bearing germline mutations in Apc are therefore important models for human colorectal cancer. These animals have been used both to understand the biology of human colorectal cancer and to screen for agents able to prevent malignant transformation of susceptible intestinal cells.
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47
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van Slooten HJ, van De Vijver MJ, Borresen AL, Eyfjörd JE, Valgardsdóttir R, Scherneck S, Nesland JM, Devilee P, Cornelisse CJ, van Dierendonck JH. Mutations in exons 5-8 of the p53 gene, independent of their type and location, are associated with increased apoptosis and mitosis in invasive breast carcinoma. J Pathol 1999; 189:504-13. [PMID: 10629550 DOI: 10.1002/(sici)1096-9896(199912)189:4<504::aid-path483>3.0.co;2-a] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In breast cancer, mutations located in the zinc-binding functional domains of the p53 gene have been reported to predict a worse prognosis and a worse response to treatment with doxorubicin, compared with mutations in other parts within exons 5-8 of the gene. Similarly, mutations in residues of p53 that directly contact DNA have been associated with a poor prognosis. To investigate whether these specific p53 mutations are associated with differences in the rate of apoptosis and/or mitosis, or expression of the anti-apoptotic Bcl-2 protein, these parameters were evaluated in 89 invasive breast cancers with a confirmed p53 mutation in exons 5-8 and in 99 tumours without a p53 mutation in exons 5-8. Neither mutations located in the zinc-binding functional domains nor mutations in residues that directly contact DNA were associated with alterations in mitotic or apoptotic activity. However, compared with the wild-type p53 tumours, both apoptotic and mitotic indices showed an approximately two-fold increase in the mutant p53 group ( p< 0. 001). The presence of a p53 mutation was also associated with the presence of tumour necrosis ( p< 0.001), high tumour grade ( p< 0. 001) and low expression of Bcl-2 ( p< 0.001). Our data support the concept that in invasive breast carcinoma, loss of p53 function is involved in enhanced proliferation rather than decreased apoptosis and that the resulting acceleration of cell turnover may enhance clonal evolution and tumour progression.
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Affiliation(s)
- H J van Slooten
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
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48
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Fan YY, Zhang J, Barhoumi R, Burghardt RC, Turner ND, Lupton JR, Chapkin RS. Antagonism of CD95 signaling blocks butyrate induction of apoptosis in young adult mouse colonic cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:C310-9. [PMID: 10444408 DOI: 10.1152/ajpcell.1999.277.2.c310] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is great interest in utilizing butyrate as a chemopreventive agent for colon tumorigenesis because of its ability to promote apoptosis in colon tumor cell lines. Because CD95 (APO-1/Fas) transduces signals resulting in apoptosis, we tested the hypothesis that butyrate-dependent colonocyte apoptosis is mediated by this death receptor. Butyrate (1 mM) exposure for 24 h upregulated expression of Fas and its ligand in young adult mouse colon (YAMC) cells. To delineate the proapoptotic effect of butyrate and to avoid the confounding effects of detachment from the extracellular matrix, adherent cell apoptosis was monitored as loss of plasma membrane asymmetry and dissipation of mitochondrial membrane potential (DeltaPsi(mt)) by laser cytometry. Soluble Fas receptor protein (Fas:Fc chimera) and caspase inhibitors (z-VAD-fmk and z-IETD-fmk) blocked butyrate induction of apoptosis. Treatment with Fas agonistic antibody (clone Jo-2) significantly induced cell death, indicating that Fas in colonocytes is functional. In addition, butyrate promoted apoptosis by inducing loss of DeltaPsi(mt) and phospholipid asymmetry of the plasma membrane after 12 and 24 h of exposure, respectively, before cell detachment. Therefore, Fas receptor-dependent signal transduction is involved in butyrate induction of apoptosis in colonocytes.
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Affiliation(s)
- Y Y Fan
- Molecular and Cell Biology Group, Faculty of Nutrition, Texas A&M University, College Station, Texas 77843, USA
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49
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Abstract
The ubiquitous bracken fern (genus Pteridium) is the only higher plant known to cause cancer naturally in animals. In addition to the well-recognized syndromes of thiamine deficiency, acute haemorrhage associated with myeloid aplasia and blindness due to retinal degeneration, it causes neoplasia of the urinary bladder and in some circumstances, of the upper gut. In addition, it has been shown to cause neoplasia in a wide range of tissues in many experimental species. The major carcinogen (and the cause of the retinal degeneration and the myeloid aplasia) has been shown to be ptaquiloside (PT), a norsesquiterpene glucoside that can be present in bracken in extraordinary concentrations, up to 13 000 ppm. The highest concentrations were found in the crosiers and young unfolding fronds. The mutagenicity, clastogenicity, teratogenicity and carcinogenicity have been convincingly demonstrated. Under alkaline conditions the loss of the glucose gives rise to the formation of a dienone intermediate which possesses a highly reactive cyclopropyl ring capable of reacting with cellular macromolecules. PT has been shown to alkylate DNA at N3 of adenines in the minor groove, preferentially in 5'-TAG and 3'-A in 5'-AA-3' sequences. It also alkylates N7 guanines in the major groove occurring in 5'-TG sequences. It is believed that these alkylations lead to mismatch repair and subsequent mutations in particular proto-oncogenes. Recently a rat model of carcinogenesis has been established using intravenously (iv) administered PT. Some epidemiological evidence has indicated higher risk of cancer in people who consume bracken crosiers, people who consume milk of cows feeding on bracken and those who live in bracken-infested areas. PT has been found in the milk of cows fed on bracken fern experimentally and the milk of bracken-fed cows has been shown to cause cancer in rats. PT carcinogenesis presents an excellent model of environmental and experimental carcinogenesis.
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Affiliation(s)
- M Shahin
- National Research Centre for Environmental Toxicology, 39 Kessels Road, Coopers Plains, Qld 4108, Australia
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Damalas A, Ben-Ze'ev A, Simcha I, Shtutman M, Leal JF, Zhurinsky J, Geiger B, Oren M. Excess beta-catenin promotes accumulation of transcriptionally active p53. EMBO J 1999; 18:3054-63. [PMID: 10357817 PMCID: PMC1171387 DOI: 10.1093/emboj/18.11.3054] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
beta-catenin is a multifunctional protein, acting both as a structural component of the cell adhesion machinery and as a transducer of extracellular signals. Deregulated beta-catenin protein expression, due to mutations in the beta-catenin gene itself or in its upstream regulator, the adenomatous polyposis coli (APC) gene, is prevalent in colorectal cancer and in several other tumor types, and attests to the potential oncogenic activity of this protein. Increased expression of beta-catenin is an early event in colorectal carcinogenesis, and is usually followed by a later mutational inactivation of the p53 tumor suppressor. To examine whether these two key steps in carcinogenesis are interrelated, we studied the effect of excess beta-catenin on p53. We report here that overexpression of beta-catenin results in accumulation of p53, apparently through interference with its proteolytic degradation. This effect involves both Mdm2-dependent and -independent p53 degradation pathways, and is accompanied by augmented transcriptional activity of p53 in the affected cells. Increased p53 activity may provide a safeguard against oncogenic deregulation of beta-catenin, and thus impose a pressure for mutational inactivation of p53 during the later stages of tumor progression.
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Affiliation(s)
- A Damalas
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
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