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Asciutti S, Akiri G, Grumolato L, Vijayakumar S, Aaronson SA. Diverse mechanisms of Wnt activation and effects of pathway inhibition on proliferation of human gastric carcinoma cells. Oncogene 2010; 30:956-66. [PMID: 21042278 PMCID: PMC3965355 DOI: 10.1038/onc.2010.475] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Human gastric carcinomas are among the most treatment refractory epithelial malignancies. Increased understanding of the underlying molecular aberrations in such tumors could provide insights leading to improved therapeutic approaches. In this study, we characterized diverse genetic aberrations leading to constitutive Wnt signaling activation in a series of human gastric carcinoma cell lines. Downregulation of TCF signaling by stable transduction of dominant negative TCF-4 (DNTCF4) resulted in inhibition of proliferation in Wnt activated AGS tumor cells. c-Myc downregulation and the associated upregulation of its repression target, p21 observed in these tumor cells, as well as the profound growth inhibition induced by c-Myc shRNA implied their c-Myc addiction. In striking contrast, Wnt activated MKN-28 and MKN-74 tumor cells appeared refractory to DNTCF4 inhibition of proliferation despite comparably decreased c-Myc expression levels. The resistance of these same tumor cells to growth inhibition by c-Myc shRNA established that their refractoriness to DNTCF was due to their independence from c-Myc for proliferation. There was no correlation between this resistance phenotype and the presence or absence of constitutive MAPK and/or AKT pathway activation, commonly observed in gastrointestinal tumors. However, in both DNTCF sensitive and resistant tumor cells with MAPK and/or AKT pathway activation, the ability of small molecule antagonists directed against either pathway to inhibit tumor cell growth was enhanced by Wnt pathway inhibition. These findings support the concept that while certain Wnt activated tumors may escape c-Myc dependence for proliferation, disruption of other oncogenic pathways can unmask cooperative antiproliferative effects for Wnt pathway downregulation.
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Affiliation(s)
- S Asciutti
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY, USA
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Abstract
OBJECTIVES Thymidylate synthase (TS) inhibitors activate human equilibrative nucleoside transporter 1. We evaluated the contribution of TS expression to determine a treatment method providing an effect from gemcitabine (GEM). METHODS The expression of 5-fluorouracil (5-FU) and GEM metabolic factors (5-FU: TS, dihydropyrimidine dehydrogenase, orotate phosphoribosyltransferase; GEM: human equilibrative nucleoside transporter 1, deoxycytidine kinase, cytidine deaminase, 5'-nucleotidase) were studied in 7 pancreatic cancer cell lines by Western blotting, and drug resistance was evaluated by 3-[4,5-dimethylthiazol]-2,5-dephenyl tetrazolium bromide assay. The expression of 5-FU factors was observed immunohistochemically in resected pancreatic cancer specimens. RESULTS Gemcitabine concentrations that inhibited colony formation by 50% correlated with TS protein expression (P = 0.0169). With a 5-FU non-growth-inhibiting dose, GEM concentrations that inhibited colony formation by 50% were significantly reduced by one fourth to one tenth. Knockout of TS expression by small interfering RNA decreased resistance to GEM in the cell lines (P = 0.0019). Immunohistochemically, TS expression related to disease-free survival time of patients treated with GEM (P = 0.0224). A high expression of 5-FU factors was detected: orotate phosphoribosyltransferase: differentiated cases (P = 0.0137), lower T factor (P = 0.0411); dihydropyrimidine dehydrogenase: nerve invasion (P = 0.0188), lymph node recurrence (P = 0.0253); TS, positive N factor (P = 0.0061). CONCLUSIONS The expression of TS provides an alternative source of substrate for DNA synthesis and positively correlates with GEM resistance and shortened patient survival.
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Tomita H, Hirata A, Yamada Y, Hata K, Oyama T, Mori H, Yamashita S, Ushijima T, Hara A. Suppressive effect of global DNA hypomethylation on gastric carcinogenesis. Carcinogenesis 2010; 31:1627-33. [PMID: 20622006 DOI: 10.1093/carcin/bgq129] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Global DNA hypomethylation and concomitant site-specific gene hypermethylation are among the most common molecular alterations in human neoplasia. Although site-specific DNA hypermethylation has been shown to be associated with the development of various tumors accompanied by transcriptional silencing of target genes, the functional significance of global DNA hypomethylation in tumorigenesis remains unclear. Previous studies have revealed that a genetic reduction of the DNA methylation levels leads to opposing effects on tumor development, depending on the tumor cell type and the stage of tumorigenesis. In the present study, we investigated the effect of DNA hypomethylation on gastric carcinogenesis in mice. The genetic reduction of DNA methylation levels suppressed the incidence, number and size of gastric tumors in two different mouse models for gastric tumorigenesis: the N-methyl-N-nitrosourea-induced model and the Apc(Min/+) mouse model that spontaneously develops gastric tumors with aging. Histological analyses revealed DNA hypomethylation to completely inhibit the development of invasive gastric tumors. These findings indicate that the reduction of DNA methylation levels suppresses gastric carcinogenesis and suggest that DNA methylation is closely associated with gastric tumorigenesis.
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Affiliation(s)
- Hiroyuki Tomita
- Department of Tumor Pathology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan
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Yasuda Y, Shimizu M, Shirakami Y, Sakai H, Kubota M, Hata K, Hirose Y, Tsurumi H, Tanaka T, Moriwaki H. Pitavastatin inhibits azoxymethane-induced colonic preneoplastic lesions in C57BL/KsJ-db/db obese mice. Cancer Sci 2010; 101:1701-7. [PMID: 20398056 PMCID: PMC11158884 DOI: 10.1111/j.1349-7006.2010.01579.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Obesity and related metabolic abnormalities are risk factors for colorectal cancer. A state of chronic inflammation and adipocytokine imbalance may play a role in colorectal carcinogenesis. Statins, which are commonly used for the treatment of hyperlipidemia, are known to possess anti-inflammatory effects. Statins also exert chemopreventive properties against various cancers. The present study examined the effects of pitavastatin, a recently developed lipophilic statin, on the development of azoxymethane (AOM)-initiated colonic premalignant lesions in C57BL/KsJ-db/db (db/db) obese mice. Male db/db mice were administrated weekly subcutaneous injections of AOM (15 mg/kg body weight) for 4 weeks and then were subsequently fed a diet containing 1 ppm or 10 ppm pitavastatin for 8 weeks. Feeding with either dose of pitavastatin significantly reduced the number of colonic premalignant lesions, beta-catenin accumulated crypts, by inhibiting proliferation and the surrounding inflammation. Pitavastatin increased the serum levels of adiponectin while conversely decreasing the serum levels of total cholesterol, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, IL-18, and leptin. Pitavastatin also caused a significant increase in the expression of phosphorylated form of the AMP-activated kinase (AMPK) protein on the colonic mucosa of AOM-treated mice. In addition, the expression levels of TNF-alpha, IL-6, IL-18, and COX-2 mRNAs on the colonic mucosa of AOM-treated mice were decreased by treatment with this agent. These findings suggest that pitavastatin attenuates chronic inflammation and improves the imbalance of adipocytokines, both of which are caused by the presence of excess adipose tissues, thereby preventing the development of colonic premalignancies in an obesity-related colon cancer model. Therefore, some types of statins, including pitavastatin, may be a useful chemoprevention modality for colon cancer in obese individuals.
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Affiliation(s)
- Yoichi Yasuda
- Department of Internal Medicine, Gifu University Graduate School of Medicine, Gifu, Japan
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55
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Vries RGJ, Huch M, Clevers H. Stem cells and cancer of the stomach and intestine. Mol Oncol 2010; 4:373-84. [PMID: 20598659 DOI: 10.1016/j.molonc.2010.05.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 05/25/2010] [Accepted: 05/31/2010] [Indexed: 12/21/2022] Open
Abstract
Cancer in the 21st century has become the number one cause of death in developed countries. Although much progress has been made in improving patient survival, tumour relapse is one of the important causes of cancer treatment failure. An early observation in the study of cancer was the heterogeneity of tumours. Traditionally, this was explained by a combination of genomic instability of tumours and micro environmental factors leading to diverse phenotypical characteristics. It was assumed that cells in a tumour have an equal capacity to propagate the cancer. This model is currently known as the stochastic model. Recently, the Cancer stem cell model has been proposed to explain the heterogeneity of a tumour and its progression. According to this model, the heterogeneity of tumours is the result of aberrant differentiation of tumour cells into the cells of the tissue the tumour originated from. Tumours were suggested to contain stem cell-like cells, the cancer stem cells or tumour-initiating cells, which are uniquely capable of propagating a tumour much like normal stem cells fuel proliferation and differentiation in normal tissue. In this review we discuss the normal stem cell biology of the stomach and intestine followed by both the stochastic and cancer stem cell models in light of recent findings in the gastric and intestinal systems. The molecular pathways underlying normal and tumourigenic growth have been well studied, and recently the stem cells of the stomach and intestine have been identified. Furthermore, intestinal stem cells were identified as the cells-of-origin of colon cancer upon loss of the tumour suppressor APC. Lastly, several studies have proposed the positive identification of a cancer stem cell of human colon cancer. At the end we compare the cancer stem cell model and the stochastic model. We conclude that clonal evolution of tumour cells resulting from genetic mutations underlies tumour initiation and progression in both cancer models. This implies that at any point during tumour development any tumour cell can revert to a cancer stem cell after having gained a clonal advantage over the original cancer stem cell. Therefore, these models represent two sides of the same coin.
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Affiliation(s)
- Robert G J Vries
- Hubrecht Institute for Developmental Biology and Stem Cell Research, Uppsalalaan 8, Utrecht, Netherlands
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56
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Barker N, Huch M, Kujala P, van de Wetering M, Snippert HJ, van Es JH, Sato T, Stange DE, Begthel H, van den Born M, Danenberg E, van den Brink S, Korving J, Abo A, Peters PJ, Wright N, Poulsom R, Clevers H. Lgr5(+ve) stem cells drive self-renewal in the stomach and build long-lived gastric units in vitro. Cell Stem Cell 2010; 6:25-36. [PMID: 20085740 DOI: 10.1016/j.stem.2009.11.013] [Citation(s) in RCA: 1126] [Impact Index Per Article: 80.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 08/21/2009] [Accepted: 11/05/2009] [Indexed: 12/14/2022]
Abstract
The study of gastric epithelial homeostasis and cancer has been hampered by the lack of stem cell markers and in vitro culture methods. The Wnt target gene Lgr5 marks stem cells in the small intestine, colon, and hair follicle. Here, we investigated Lgr5 expression in the stomach and assessed the stem cell potential of the Lgr5(+ve) cells by using in vivo lineage tracing. In neonatal stomach, Lgr5 was expressed at the base of prospective corpus and pyloric glands, whereas expression in the adult was predominantly restricted to the base of mature pyloric glands. Lineage tracing revealed these Lgr5(+ve) cells to be self-renewing, multipotent stem cells responsible for the long-term renewal of the gastric epithelium. With an in vitro culture system, single Lgr5(+ve) cells efficiently generated long-lived organoids resembling mature pyloric epithelium. The Lgr5 stem cell marker and culture method described here will be invaluable tools for accelerating research into gastric epithelial renewal, inflammation/infection, and cancer.
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Affiliation(s)
- Nick Barker
- Hubrecht Institute for Developmental Biology and Stem Cell Research, Uppsalalaan 8, 3584CT Utrecht & University Medical Centre Utrecht, Netherlands
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57
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Xiao C, Ogle SA, Schumacher MA, Orr–Asman MA, Miller ML, Lertkowit N, Varro A, Hollande F, Zavros Y. Loss of parietal cell expression of Sonic hedgehog induces hypergastrinemia and hyperproliferation of surface mucous cells. Gastroenterology 2010; 138:550-61, 561.e1-8. [PMID: 19909751 PMCID: PMC4269486 DOI: 10.1053/j.gastro.2009.11.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 11/03/2009] [Accepted: 11/05/2009] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Sonic Hedgehog (Shh) is expressed in the adult stomach, but its role as a gastric morphogen is unclear. We sought to identify mechanisms by which Shh might regulate gastric epithelial cell function and differentiation. METHODS Mice with a parietal cell-specific deletion of Shh (HKCre/Shh(KO)) were created. Gastric morphology and function were studied in control and HKCre/Shh(KO) mice between 1 and 8 months of age. RESULTS In contrast to control mice, HKCre/Shh(KO) mice developed gastric hypochlorhydria, hypergastrinemia, and a phenotype that resembled foveolar hyperplasia. The fundic mucosa of HKCre/Shh(KO) mice had an expanded surface pit cell lineage that was documented by increased incorporation of bromodeoxyuridine and was attributed to the hypergastrinemia. Compared with controls, numbers of total mucous neck and zymogen cells were significantly decreased in stomachs of HKCre/Shh(KO) mice. In addition, zymogen and neck cell markers were coexpressed in the same cell populations, indicating disrupted differentiation of the zymogen cell lineage from the mucous neck cells in the stomachs of HKCre/Shh(KO) mice. Laser capture microdissection of the surface epithelium, followed by quantitative reverse-transcription polymerase chain reaction, revealed a significant increase in expression of Indian Hedgehog, glioma-associated oncogene homolog 1, Wnt, and cyclin D1. Laser capture microdissection analysis also showed a significant increase in Snail with a concomitant decrease in E-cadherin. CONCLUSIONS In the stomachs of adult mice, loss of Shh from parietal cells results in hypochlorhydria and hypergastrinemia. Hypergastrinemia might subsequently induce increased Hedgehog and Wnt signaling in the surface pit epithelium, resulting in hyperproliferation.
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Affiliation(s)
- Chang Xiao
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Sally A. Ogle
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Michael A. Schumacher
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Melissa A. Orr–Asman
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Marian L. Miller
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nantaporn Lertkowit
- The Physiological Laboratory, School of Biomedical Sciences, Crown Street, University of Liverpool, Liverpool, England
| | - Andrea Varro
- The Physiological Laboratory, School of Biomedical Sciences, Crown Street, University of Liverpool, Liverpool, England
| | - Frederic Hollande
- CNRS UMR5203, Montpellier, France,INSERM Unité 661, Montpellier, France,Université Montpellier I, Montpellier, France,Université Montpellier II, Montpellier, France,Cellular and Molecular Oncology Department, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Yana Zavros
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Iwasa J, Shimizu M, Shiraki M, Shirakami Y, Sakai H, Terakura Y, Takai K, Tsurumi H, Tanaka T, Moriwaki H. Dietary supplementation with branched-chain amino acids suppresses diethylnitrosamine-induced liver tumorigenesis in obese and diabetic C57BL/KsJ-db/db mice. Cancer Sci 2010; 101:460-7. [PMID: 19906067 PMCID: PMC11159020 DOI: 10.1111/j.1349-7006.2009.01402.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Obesity and related metabolic abnormalities, including insulin resistance, are risk factors for hepatocellular carcinoma in non-alcoholic steatohepatitis as well as in chronic viral hepatitis. Branched-chain amino acids (BCAA), which improve insulin resistance, inhibited obesity-related colon carcinogenesis in a rodent model, and also reduced the incidence of hepatocellular carcinoma in obese patients with liver cirrhosis. In the present study, we determined the effects of BCAA on the development of diethylnitrosamine (DEN)-induced liver tumorigenesis in obese C57BL/KsJ-db/db (db/db) mice with diabetes mellitus. Male db/db mice were given tap water containing 40 ppm DEN for an initial 2 weeks and thereafter they received a basal diet containing 3.0% of BCAA or casein, which served as a nitrogen content-matched control of BCAA, throughout the experiment. Supplementation with BCAA significantly reduced the total number of foci of cellular alteration, a premalignant lesion of the liver, and the expression of insulin-like growth factor (IGF)-1, IGF-2, and IGF-1 receptor in the liver when compared to the casein supplementation. BCAA supplementation for 34 weeks also significantly inhibited both the development of hepatocellular neoplasms and the proliferation of hepatocytes in comparison to the basal diet or casein-fed groups. Supplementation with BCAA improved liver steatosis and fibrosis and inhibited the expression of alpha-smooth muscle actin in the DEN-treated db/db mice. The serum levels of glucose and leptin decreased by dietary BCAA, whereas the value of the quantitative insulin sensitivity check index increased by this agent, indicating the improvement of insulin resistance and hyperleptinemia. In conclusion, oral BCAA supplementation improves insulin resistance and prevents the development of liver tumorigenesis in obese and diabetic mice.
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Affiliation(s)
- Junpei Iwasa
- Department of Medicine, Gifu University Graduate School of Medicine, Gifu, Japan
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59
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Yasuda Y, Shimizu M, Sakai H, Iwasa J, Kubota M, Adachi S, Osawa Y, Tsurumi H, Hara Y, Moriwaki H. (−)-Epigallocatechin gallate prevents carbon tetrachloride-induced rat hepatic fibrosis by inhibiting the expression of the PDGFRβ and IGF-1R. Chem Biol Interact 2009; 182:159-64. [DOI: 10.1016/j.cbi.2009.07.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/13/2009] [Accepted: 07/22/2009] [Indexed: 02/07/2023]
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Maiese K, Chong ZZ, Shang YC, Hou J. A "FOXO" in sight: targeting Foxo proteins from conception to cancer. Med Res Rev 2009; 29:395-418. [PMID: 18985696 DOI: 10.1002/med.20139] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The successful treatment for multiple disease entities can rest heavily upon the ability to elucidate the intricate relationships that govern cellular proliferation, metabolism, survival, and inflammation. Here we discuss the therapeutic potential of the mammalian forkhead transcription factors predominantly in the O class, FoxO1, FoxO3, FoxO4, and FoxO6, which play a significant role during normal cellular function as well as during progressive disease. These transcription factors are integrated with several signal transduction pathways, such as Wnt proteins, that can regulate a broad array of cellular process that include stem cell proliferation, aging, and malignancy. FoxO transcription factors are attractive considerations for strategies directed against human cancer in light of their pro-apoptotic effects and ability to lead to cell cycle arrest. Yet, FoxO proteins can be associated with infertility, cellular degeneration, and unchecked cellular proliferation. As our knowledge continues to develop for this novel family of proteins, potential clinical applications for the FoxO family should heighten our ability to limit disease progression without clinical compromise.
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Affiliation(s)
- Kenneth Maiese
- Division of Cellular and Molecular Cerebral Ischemia, Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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61
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Hosoya K, Yamashita S, Ando T, Nakajima T, Itoh F, Ushijima T. Adenomatous polyposis coli 1A is likely to be methylated as a passenger in human gastric carcinogenesis. Cancer Lett 2009; 285:182-9. [PMID: 19527921 DOI: 10.1016/j.canlet.2009.05.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 05/14/2009] [Accepted: 05/15/2009] [Indexed: 12/29/2022]
Abstract
Many promoter CpG islands (CGIs) are methylated as a consequence of or in association with carcinogenesis (passenger), in addition to being a cause of carcinogenesis (driver). In gastric cancers, promoter 1A of the adenomatous polyposis coli (APC) gene is frequently methylated, and is often discussed as a driver. However, the actual role of 1A methylation is unclear because the same APC protein is coded by two transcripts from two promoters, 1A and 1B, and their relative expression levels in gastric mucosae have not been quantified. To clarify this issue, we first identified detailed transcription start sites of 1A and 1B transcripts. We then confirmed that, among nine gastric cancer cell lines, 1A methylation, if present, could repress 1A transcription while 1B was expressed and not methylated. In primary samples, 1B expression was 15-fold higher than 1A expression in gastric mucosae of healthy volunteers, and was decreased markedly in non-cancerous gastric mucosae of cancer patients. Quantitative methylation analysis showed that promoter 1A was methylated at similar levels (20-40%) in healthy individuals and non-cancerous gastric mucosae of cancer patients, and promoter 1B was never methylated in any samples, including gastric cancers. These findings strongly indicated that methylation of APC promoter 1A is a passenger, and suggested that marked down-regulation of 1B expression could be related to formation of a field predisposed to gastric cancers.
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Affiliation(s)
- Kosuke Hosoya
- Carcinogenesis Division, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
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Pollard P, Deheragoda M, Segditsas S, Lewis A, Rowan A, Howarth K, Willis L, Nye E, McCart A, Mandir N, Silver A, Goodlad R, Stamp G, Cockman M, East P, Spencer-Dene B, Poulsom R, Wright N, Tomlinson I. The Apc 1322T mouse develops severe polyposis associated with submaximal nuclear beta-catenin expression. Gastroenterology 2009; 136:2204-2213.e1-13. [PMID: 19248780 DOI: 10.1053/j.gastro.2009.02.058] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/16/2009] [Accepted: 02/11/2009] [Indexed: 01/21/2023]
Abstract
BACKGROUND & AIMS We previously demonstrated that the 2 APC mutations in human colorectal tumors are coselected, because tumorigenesis requires an optimal level of Wnt signaling. We and others subsequently showed that the truncated APC proteins in colorectal tumors usually retain a total of 1-2 beta-catenin binding/degradation repeats (20AARs); very few intestinal tumors have proteins with no 20AARs. The coselection of the "2 hits" at APC makes it difficult to undertake further mechanistic studies in this area in humans. In mice, however, second hits appear to vary with the strain or genetic background used. This suggested the possibility of creating suboptimal Apc genotypes in the mouse. METHODS We have constructed a mouse, Apc(1322T), with a mutant protein retaining one 20AAR. After repeated backcrossing to the C57BL/6J background, we compared the 1322T animals with the widely used Min mouse in which the mutant Apc protein has zero 20AARs. RESULTS In both mice, intestinal adenomas showed copy-neutral loss of heterozygosity, making them homozygous for the mutant Apc allele. 1322T animals had markedly more severe polyposis, with earlier-onset, larger, more numerous, and more severely dysplastic adenomas. 1322T tumors also had more marked Paneth cell differentiation and higher frequencies of crypt fission. Somewhat surprisingly, nuclear beta-catenin expression was lower in 1322T than Min tumors. CONCLUSIONS We propose that the Apc(1322T) mutation produces submaximal beta-catenin levels that promote early tumor growth more effectively than the Apc(Min) mutation.
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Affiliation(s)
- Patrick Pollard
- Molecular and Population Genetics Laboratory, London Research Institute, Cancer Research UK, London, England
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Sheng HQ, Chen J, Lai MD. [Use of Apc(Min/+) mouse model in the studies of intestinal tumors]. YI CHUAN = HEREDITAS 2009; 30:277-82. [PMID: 18331993 DOI: 10.3724/sp.j.1005.2008.00277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
More than thirty kinds of mutant or knockout mice bearing intestinal neoplasm have been reported up to the present. Apc(Min/+) mouse holding multiple intestinal neoplasia, provides an appropriate model to evaluate human familial adenomatous polyposis. APC is an important tumor-suppressor gene in the Wnt pathway, which is involved in the pivotal signal transduction cascade in animal embryogenesis and colorectal carcinogenesis. Apc(Min/+) mouse model was presented as aspects of the strain background, genotype/phenotype, divergent canonical Wnt signaling pathway, methylation of tumor-suppressor gene, TGF-b signaling pathway and multidrug resistance gene, etc. This review also introduced the application and signification of the mouse model in studies of anti-colorectal tumor drugs.
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Affiliation(s)
- Hong-Qiang Sheng
- Department of Pathology and Pathophysiology, School of Medicine, Zhejiang University, Hangzhou 310058, China.
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64
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Yu J, Tao Q, Cheng YY, Lee KY, Ng SSM, Cheung KF, Tian L, Rha SY, Neumann U, Röcken C, Ebert MPA, Chan FKL, Sung JJY. Promoter methylation of the Wnt/beta-catenin signaling antagonist Dkk-3 is associated with poor survival in gastric cancer. Cancer 2009; 115:49-60. [PMID: 19051296 DOI: 10.1002/cncr.23989] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Abnormal activation of the Wnt/beta-catenin signaling pathway is common and critical in the pathogenesis of digestive cancers. In this study, the authors investigated the promoter methylation of the dickkopf homolog 3 gene Dkk-3 in these cancers and its prognostic significance in gastric cancer. METHODS Dkk-3 methylation was assessed in 173 patients with gastric cancers (including 104 patients who were followed for up to 4090 days) and in 128 patients with colorectal cancer. Cell growth was evaluated by using a colony-formation assay. For survival analyses, the authors used Kaplan-Meier plots, the log-rank test, and Cox proportional regression. RESULTS Dkk-3 was silenced or down-regulated in 12 of 17 gastric cancer cell lines (70.6%) and in 3 of 9 colon cancer cell lines (33.3%). The loss of gene expression was associated with promoter methylation, which could be restored by demethylating agents. Ectopic expression of Dkk-3 suppressed colony formation. Moreover, methylation of Dkk-3 was detected in 117 of 173 primary gastric tumors (67.6%) and in 67 of 128 colorectal tumors (52.3%). The clinical significance and the prognostic value of Dkk-3 methylation also were examined in 104 gastric cancers and in 84 colorectal cancers. Multivariate analysis indicated that Dkk-3 methylation was associated significantly and independently with poor disease survival (relative risk, 2.534; 95% confidence interval, 1.54-4.17; P=.002) in gastric cancer, but not in colorectal cancer. Kaplan-Meier survival curves revealed that patients who had Dkk-3 methylated gastric cancers had a significantly shorter survival (median, 0.76 years) compared with patients who did not have Dkk-3 methylation (median, 2.68 years; P<.0001; log-rank test). CONCLUSIONS Epigenetic silencing of the Dkk-3 gene by promoter methylation was a common event in gastric cancer and was associated with a poor outcome in such patients.
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Affiliation(s)
- Jun Yu
- Institute of Digestive Disease, Department of Medicine, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR.
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Humar B, Blair V, Charlton A, More H, Martin I, Guilford P. E-cadherin deficiency initiates gastric signet-ring cell carcinoma in mice and man. Cancer Res 2009; 69:2050-6. [PMID: 19223545 DOI: 10.1158/0008-5472.can-08-2457] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The importance of loss of the cell-cell adhesion molecule E-cadherin (encoded by CDH1) to tumor progression is well established. However, CDH1 germ-line mutations predispose to the cancer susceptibility syndrome hereditary diffuse gastric cancer (HDGC), suggesting a role for E-cadherin in tumor initiation. The earliest indications of cancer in the stomachs of CDH1 mutation carriers are microscopic foci of intramucosal signet-ring cell carcinoma (SRCC; designated "eHDGC"). Here, we used N-methyl-N-nitrosourea (MNU) to promote gastric carcinogenesis in wild-type (wt) and cdh1(+/-) mice. MNU induced a variety of gastric tumors; however, intramucosal SRCC developed with an 11 times higher incidence in cdh1(+/-) mice compared with wt mice. The murine SRCC resembled the human eHDGCs in that they were hypoproliferative, lacked nuclear beta-catenin accumulation, and had reduced membrane localization of E-cadherin and its interacting junctional proteins. The down-regulation of E-cadherin in the murine SRCCs confirmed the importance of the second CDH1 hit to the initiation of diffuse gastric cancer. CDH1 promoter hypermethylation has been proposed to be a major second hit in advanced HDGC; however, its contribution to eHDGC was unknown. We thus examined a series of human eHDGC and detected CDH1 promoter methylation in 50% of foci. Promoter methylation was accompanied by reduced wt CDH1 mRNA levels in the foci and had a monoclonal pattern, consistent with an epigenetic initiation of disease. Together, these findings provide compelling evidence for a deficiency in cell-to-cell adhesion being sufficient to initiate diffuse gastric cancer in the absence of hyperproliferation and beta-catenin activation.
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Affiliation(s)
- Bostjan Humar
- Cancer Genetics Laboratory, Department of Biochemistry, University of Otago, Dunedin, New Zealand.
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The "O" class: crafting clinical care with FoxO transcription factors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 665:242-60. [PMID: 20429429 DOI: 10.1007/978-1-4419-1599-3_18] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Forkhead Transcription Factors: Vital Elements in Biology and Medicine provides a unique platform for the presentation of novel work and new insights into the vital role that forkhead transcription factors play in both cellular physiology as well as clinical medicine. Internationally recognized investigators provide their insights and perspectives for a number of forkhead genes and proteins that may have the greatest impact for the development of new strategies for a broad array of disorders that can involve aging, cancer, cardiac function, neurovascular integrity, fertility, stem cell differentiation, cellular metabolism, and immune system regulation. Yet, the work clearly sets a precedent for the necessity to understand the cellular and molecular function of forkhead proteins since this family of transcription factors can limit as well as foster disease progression depending upon the cellular environment. With this in mind, our concluding chapter for Forkhead Transcription Factors: Vital Elements in Biology andMedicine offers to highlight both the diversity and complexity of the forkhead transcription family by focusing upon the mammalian forkhead transcription factors of the O class (FoxOs) that include FoxO1, FoxO3, FoxO4, and FoxO6. FoxO proteins are increasingly considered to represent unique cellular targets that can control numerous processes such as angiogenesis, cardiovascular development, vascular tone, oxidative stress, stem cell proliferation, fertility, and immune surveillance. Furthermore, FoxO transcription factors are exciting considerations for disorders such as cancer in light of their pro-apoptotic and inhibitory cell cycle effects as well as diabetes mellitus given the close association FoxOs hold with cellular metabolism. In addition, these transcription factors are closely integrated with several novel signal transduction pathways, such as erythropoietin and Wnt proteins, that may influence the ability of FoxOs to lead to cell survival or cell injury. Further understanding of both the function and intricate nature of the forkhead transcription factor family, and in particular the FoxO proteins, should allow selective regulation of cellular development or cellular demise for the generation of successful future clinical strategies and patient well-being.
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Maiese K, Chong ZZ, Shang YC, Hou J. Clever cancer strategies with FoxO transcription factors. Cell Cycle 2008; 7:3829-39. [PMID: 19066462 DOI: 10.4161/cc.7.24.7231] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Given that cancer and related disorders affect a wide spectrum of the world's population, and in most cases are progressive in nature, it is essential that future care must overcome the present limitations of existing therapies in the absence of toxic side effects. Mammalian forkhead transcription factors of the O class (FoxOs) may fill this niche since these proteins are increasingly considered to represent unique cellular targets directed against human cancer in light of their pro-apoptotic effects and ability to lead to cell cycle arrest. Yet, FoxOs also can significantly affect normal cell survival and longevity, requiring new treatments for neoplastic growth to modulate novel pathways that integrate cell proliferation, metabolism, inflammation and survival. In this respect, members of the FoxO family are extremely compelling to consider since these transcription factors have emerged as versatile proteins that can control angiogenesis, stem cell proliferation, cell adhesion and autoimmune disease. Further elucidation of FoxO protein function during neoplastic growth should continue to lay the foundation for the successful translation of these transcription factors into novel and robust clinical therapies for cancer.
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Affiliation(s)
- Kenneth Maiese
- Division of Cellular and Molecular Cerebral Ischemia, Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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Takasu S, Tsukamoto T, Cao XY, Toyoda T, Hirata A, Ban H, Yamamoto M, Sakai H, Yanai T, Masegi T, Oshima M, Tatematsu M. Roles of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 expression and beta-catenin activation in gastric carcinogenesis in N-methyl-N-nitrosourea-treated K19-C2mE transgenic mice. Cancer Sci 2008; 99:2356-64. [PMID: 19018769 PMCID: PMC11159403 DOI: 10.1111/j.1349-7006.2008.00983.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 08/16/2008] [Accepted: 08/18/2008] [Indexed: 12/17/2022] Open
Abstract
K19-C2mE transgenic (Tg) mice, simultaneously expressing cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) in the gastric mucosa under the cytokeratin 19 gene promoter, were here treated with N-methyl-N-nitrosourea (MNU) and inoculated with Helicobacter pylori (H. pylori) to investigate gastric carcinogenesis. Wild-type (WT) and Tg mice undergoing MNU treatment frequently developed tumors in the pyloric region (100% and 94.7%, respectively); multiplicity in Tg was higher than that in WT (P < 0.05) with H. pylori infection. Larger pyloric tumors were more frequently observed in Tg than in WT (P < 0.05). In addition, Tg developed fundic tumors, where WT did not. No gastric tumors were observed without MNU treatment. Transcripts of TNF-alpha, iNOS, IL-1beta, and CXCL14 were up-regulated with H. pylori infection in both genotypes and were also increased more in Tg than in WT within H. pylori-inoculated animals. Immunohistochemical analysis demonstrated significantly greater beta-catenin accumulation in pyloric tumors, compared with those in the fundus (P < 0.01) with mutations of exon 3; 18.2% and 31.6% in MNU-alone and MNU + H. pylori-treated WT, whereas 21.4% and 62.5% was observed in the Tg, respectively; the latter significantly higher (P < 0.05), suggesting the role of H. pylori in Wnt activation. In conclusion, K19-C2mE mice promoted gastric cancer in both fundic and pyloric regions. Furthermore beta-catenin activation may play the important role of pyloric carcinogenesis especially in H. pylori-infected Tg. Induction of various inflammatory cytokines in addition to overexpression of COX-2/mPGES-1 could be risk factors of gastric carcinogenesis and may serve as a better gastric carcinogenesis model.
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Affiliation(s)
- Shinji Takasu
- Division of Oncological Pathology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan
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Maiese K, Chong ZZ, Shang YC, Hou J. Rogue proliferation versus restorative protection: where do we draw the line for Wnt and forkhead signaling? Expert Opin Ther Targets 2008; 12:905-16. [PMID: 18554157 DOI: 10.1517/14728222.12.7.905] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Disease entities such as diabetes, neurodegeneration and cardiovascular disorders affect a significant portion of the world's population. OBJECTIVE Given that cellular survival and longevity in multiple disorders are tied to oxidative stress, apoptotic cell injury and immune system deregulation, the development of robust therapeutic strategies rests heavily upon the ability to balance each of these parameters. METHODS Here we discuss two exciting signaling pathways, namely Wnt and mammalian forkhead transcription factors predominantly of the O class superfamily, which can share integrated cytoprotective pathways during oxidative stress but may also adversely influence cellular survival and promote cancer cell proliferation. CONCLUSION Future investigations must elucidate the cellular determinants that govern the ability of Wnt and forkhead proteins to promote cellular longevity and possible disease remission but also allow for detrimental biological consequences and clinical compromise.
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Affiliation(s)
- Kenneth Maiese
- Wayne State University School of Medicine, Department of Neurology, 8C-1 UHC, 4201 Street, Antoine, Detroit, MI 48201, USA.
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Guo Y, Xie J, Rubin E, Tang YX, Lin F, Zi X, Hoang BH. Frzb, a secreted Wnt antagonist, decreases growth and invasiveness of fibrosarcoma cells associated with inhibition of Met signaling. Cancer Res 2008; 68:3350-60. [PMID: 18451162 DOI: 10.1158/0008-5472.can-07-3220] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Soft tissue sarcomas (STS) have a strong propensity for aggressive growth and metastasis. We showed that the secreted Wnt antagonist Frzb exhibited potent antitumor activity against prostate cancer, an epithelial type of malignancy. In this study, we further showed the antitumor efficacy of Frzb in STS, a mesenchymal group of cancer. Frzb transfection of HT1080 (fibrosarcoma) and SW872 (liposarcoma) cell lines and their conditioned media resulted in a significant reduction in cellular invasion, motility, and colony formation in soft agar compared with vector control-transfected cells. In a xenograft mouse model, Frzb dramatically suppressed tumor growth of HT1080 cells in nude mice. In a tail-vein injection metastatic model, Frzb-transfected HT1080 cells formed fewer and smaller lung nodules than vector control cells. In addition, we identified new mechanisms for Frzb antitumor activities. Frzb reduced c-Met expression and inhibited Met-mediated signaling, associated with up-regulation of epithelial markers (i.e., keratins 8 and 18) and down-regulation of mesenchymal markers (i.e., vimentin, N-cadherin, fibronectin, Slug, and Twist). Similar to Frzb, silencing of c-Met by short hairpin RNA or using a dominant-negative LRP5 receptor also suppressed Met signaling, leading to reduced cellular motility, invasion, and in vivo tumor growth. Given recent studies indicating an important role of c-Met in sarcoma development and progression, our data showed that Frzb expression was significantly inversely correlated with Met expression in both STS cell lines and tissues. These results suggested the usefulness of Frzb in modulating Met signaling as a new treatment strategy for STS.
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Affiliation(s)
- Yi Guo
- Department of Orthopedic Surgery, Chao Family Comprehensive Cancer Center, University of California, Irvine, CA 92868, USA
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Oyama T, Yamada Y, Hata K, Tomita H, Hirata A, Sheng H, Hara A, Aoki H, Kunisada T, Yamashita S, Mori H. Further upregulation of beta-catenin/Tcf transcription is involved in the development of macroscopic tumors in the colon of ApcMin/+ mice. Carcinogenesis 2008; 29:666-72. [PMID: 18204079 DOI: 10.1093/carcin/bgn001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Apc(Min/+) mouse, a mouse model for human familial adenomatosis polyposis, contains a truncating mutation in the Apc gene and spontaneously develops intestinal tumors. Our previous study revealed two distinct stages of tumorigenesis in the colon of Apc(Min/+) mouse: microadenomas and macroscopic tumors. Microadenomas already have lost their remaining allele of the Apc and all microadenomas show accumulation of beta-catenin, indicating that activation of the canonical Wnt pathway is an initiating event in the tumorigenesis. This study shows that expression of nuclear beta-catenin in macroscopic tumors is further upregulated in comparison with that in microadenomas. Furthermore, transcriptional activity of beta-catenin/T-cell factor (Tcf) signaling, assessed using beta-catenin/Tcf reporter transgenic mice, is higher in the macroscopic tumors than that in microadenomas. In addition, the expression level of Dickkopf-1, which is known to be a negative modifier of the canonical Wnt pathway, was reduced only in colon tumors. These results suggest that activation of beta-catenin/Tcf transcription plays a role not only in the initiation stage but also in the promotion stage of colon carcinogenesis in Apc(Min/+) mice.
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Affiliation(s)
- Takeru Oyama
- Department of Tumor Pathology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan
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