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Tumorigenesis
Kinds of Tumorigenesis Selected AbstractsAMP-activated protein kinase and cancerACTA PHYSIOLOGICA, Issue 1 2009W. Wang Abstract AMP-activated protein kinase (AMPK) is a cellular energy sensor that is conserved in eukaryotes. Elevated AMP/ATP ratio activates AMPK, which inhibits energy-consuming processes and activates energy-producing processes to restore the energy homeostasis inside the cell. AMPK activators, metformin and thiazolidinediones, are used for the treatment of type II diabetes. Recently, reports have indicated that AMPK may also be a beneficial target for cancer treatment. Cancer cells have characteristic metabolic changes different from normal cells and, being a key metabolic regulator, AMPK may regulate the switch. AMPK may act to inhibit tumorigenesis through regulation of cell growth, cell proliferation, autophagy, stress responses and cell polarity. [source] Axillary Basal Cell Carcinoma: Literature Survey and Case ReportDERMATOLOGIC SURGERY, Issue 11 2001Erin S. Gardner MD Background. Primary basal cell carcinoma (BCC) in the axilla has rarely been reported in the literature. No systematic review has yet been conducted. Objective. To present a case of basal cell carcinoma of the axilla. This is a rare presentation of a common disease in a non-sun-exposed part of the body. Methods. An extensive literature search for axillary BCCs was performed. An additional case is reported. Results. Only 14 cases of primary axillary BCC have been reported in the literature. Metastatic axillary BCC is also rarely reported. Conclusion. BCC in the axilla is extremely uncommon. Factors other than sun exposure are likely involved in tumorigenesis. [source] Basolateral junctions are sufficient to suppress epithelial invasion during Drosophila oogenesisDEVELOPMENTAL DYNAMICS, Issue 2 2007Przemyslaw Szafranski Abstract Epithelial junctions play crucial roles during metazoan evolution and development by facilitating tissue formation, maintenance, and function. Little is known about the role of distinct types of junctions in controlling epithelial transformations leading to invasion of neighboring tissues. Discovering the key junction complexes that control these processes and how they function may also provide mechanistic insight into carcinoma cell invasion. Here, using the Drosophila ovary as a model, we show that four proteins of the basolateral junction (BLJ), Fasciclin-2, Neuroglian, Discs-large, and Lethal-giant-larvae, but not proteins of other epithelial junctions, directly suppress epithelial tumorigenesis and invasion. Remarkably, the expression pattern of Fasciclin-2 predicts which cells will invade. We compared the apicobasal polarity of BLJ tumor cells to border cells (BCs), an epithelium-derived cluster that normally migrates during mid-oogenesis. Both tumor cells and BCs differentiate a lateralized membrane pattern that is necessary but not sufficient for invasion. Independent of lateralization, derepression of motility pathways is also necessary, as indicated by a strong linear correlation between faster BC migration and an increased incidence of tumor invasion. However, without membrane lateralization, derepression of motility pathways is also not sufficient for invasion. Our results demonstrate that spatiotemporal patterns of basolateral junction activity directly suppress epithelial invasion by organizing the cooperative activity of distinct polarity and motility pathways. Developmental Dynamics 236:364,373, 2007. © 2006 Wiley-Liss, Inc. [source] Original article: The expression of CFL1 and N-WASP in esophageal squamous cell carcinoma and its correlation with clinicopathological featuresDISEASES OF THE ESOPHAGUS, Issue 6 2010Wei-Sen Wang SUMMARY Cofilin1 (CFL1) is an actin-modulating protein, which belongs to the ADF/Cofilin family. Neural Wiskott,Aldrich syndrome protein (N-WASP) is the key regulator of the actin cytoskeleton, a member of Wiskott-Aldrich syndrome protein family. They have been suggested to be involved in cancer cell invasion and metastasis. In this study, the expression patterns of CFL1 and N-WASP in normal esophageal mucosa and esophageal squamous cell carcinoma (ESCC) and their correlation with clinical characteristics were investigated. Immunohistochemical staining showed that CFL1 was expressed in nuclear and cytoplasm of cancer cells. However, N-WASP was mainly found in the cytoplasm of the cancer cells. There were significant evidences that proved that CFL1 is correlated with clinicopathological factors in ESCC, such as infiltration depth, lymph node metastasis and pathological staging (P < 0.05). It is also proved that N-WASP is related to lymph node metastasis and pathological staging in ESCC (P < 0.05). Kaplan,Meier analysis showed that there was no correlation between CFL1 and N-WASP protein expression and survival (P > 0.05). Moreover, the mRNA expression of CFL1 and N-WASP was detected by quantitative real time PCR in 70 tissue specimens. The results showed that CFL1 mRNA level was over-expressed in ESCC tissue (P < 0.05), while N-WASP mRNA expression level was not different between cancerous tissues and adjacent normal esophageal mucosa (P > 0.05). Also, CFL1 mRNA expression was significantly associated with regional lymph node metastasis and pathological staging (P < 0.05). Kaplan,Meier analysis showed that there was no correlation between CFL1 and N-WASP mRNA expression and survival (P > 0.05). Our findings suggested that CFL1 and N-WASP may play an important role in the tumorigenesis of ESCC, and to be the candidate novel biomarkers for the diagnosis and prognosis of ESCC. These findings may have implications for targeted therapies in patients with ESCC. [source] Environmental carcinogens and p53 tumor-suppressor gene interactions in a transgenic mouse model for mammary carcinogenesisENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2-3 2002Daniel Medina Abstract Mouse mammary tumorigenesis is greatly influenced by a variety of exogenous agents, such as MMTV, chemical carcinogens (i.e., polycyclic aromatic hydrocarbons), and radiation, as well as by endogenous/physiological factors, such as steroid hormones, tumor-suppressor genes (i.e., Brca1/2,p53), and gene products of modifier genes. In the mouse model, the most frequently used chemical carcinogen has been 7,12-dimethylbenz[a]anthracene (DMBA), which activates the Ha- ras gene but does not alter the p53 tumor-suppressor gene. However, on an existing background of p53 gene alteration, low doses of DMBA are strongly cocarcinogenic. Using a transgenic model system, in which the p53 gene was deleted in the mammary gland, we examined the carcinogenic effects of a variety of external agents and internal factors given at either low doses or physiological doses. These agents/factors included DMBA, ,-radiation, Brca2 heterozygosity, and steroid hormones. All agents/factors increased the tumorigenic response of the p53 null mammary cells, even under conditions where no tumorigenic response was observed in the p53 wildtype mammary cell. The strongest cocarcinogenic effect was observed with the steroid hormone progesterone. The majority of tumors were highly aneuploid and composed of nuclear igh-grade cells. The mechanism for the aneuploidy and secondary events associated with high tumorigenicity were examined using array technology. These results demonstrate that, on a background of underlying genetic instability, very low doses of environmental mutagens and mitogens can produce strong cocarcinogenic effects. Environ. Mol. Mutagen. 39:178,183, 2002. © 2002 Wiley-Liss, Inc. [source] Dermal benzene and trichloroethylene induce aneuploidy in immature hematopoietic subpopulations in vivoENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2001Cynthia R. Giver Abstract Accumulation of genetic damage in long-lived cell populations with proliferative capacity is implicated in tumorigenesis. Hematopoietic stem cells (hsc) maintain lifetime hematopoiesis, and recent studies demonstrate that hsc in leukemic patients are cytogenetically aberrant. We postulated that exposure to agents associated with increased leukemia risk would induce genomic changes in cells in the hsc compartment. Aneusomy involving chromosomes 2 and 11 in sorted hsc (Lin,c-kit+Sca-1+) and maturing lymphoid and myeloid cells from mice that received topical doses of benzene (bz) or trichloroethylene (TCE) was quantified using fluorescence in situ hybridization. Six days after bz or TCE exposure, aneuploid cells in the hsc compartment increase four- to eightfold in a dose- and schedule-independent manner. Aneuploid lymphoid and myeloid cells from bz- and TCE-treated mice approximate controls, except after repeated benzene exposures. Aneuploid cells are more frequent in the hsc compartment than in mature hematopoietic subpopulations. Hematotoxicity was also quantified in bz- and TCE-exposed hematopoietic subpopulations using two colony-forming assays: CFU-GM (colony-forming units/granulocyte-macrophage progenitors) and CAFC (cobblestone area,forming cells). Data indicate that bz is transiently cytotoxic (,1 week) to hsc subpopulations, and induces more persistent toxicity (>2 weeks) in maturing, committed progenitor subpopulations. TCE is not hematotoxic at the doses applied. In conclusion, we provide direct evidence for induction of aneuploidy in cells in the hsc compartment by topical exposure to bz and TCE. Disruption of genomic integrity and/or toxicity in hsc subpopulations may be one step in leukemic progression. Environ. Mol. Mutagen. 37:185,194, 2001. © 2001 Wiley-Liss, Inc. [source] Multilineage progression of genetically unstable tumor subclones in cutaneous T-cell lymphomaEXPERIMENTAL DERMATOLOGY, Issue 8 2004Albert Rübben Abstract:, Molecular analysis of solid malignant tumors has suggested multilineage progression of genetically unstable subclones during early stages of tumorigenesis as a common mechanism of tumor cell evolution. We have investigated whether multilineage progression is a feature of cutaneous T-cell lymphoma (CTCL). To identify individual tumor cell subclones, we determined the pattern of mutations within microsatellite DNA obtained from multiple histomorphologically confined tumor cell nests of mycosis fungoides (MF) and lymphomatoid papulosis (LyP) lesions. Tumor cells were isolated by laser microdissection, and allelotypes were determined at microsatellite markers D6S260, D9S162, D9S171, D10S215, TP53.PCR15, and D18S65. Nine cases of MF and one patient with anaplastic large cell lymphoma (ALCL) originating from LyP were analyzed at 277 different microdissected areas obtained from 31 individual lesions. Three specimens of cutaneous lichen planus microdissected at 26 areas served as the control tissue. Microsatellite instability in microdissected tissue [MSI(md-tissue)] was detected in tumor tissues of all CTCL patients. One hundred and fifty-seven of 469 analyzed polymerase chain reaction (PCR) amplifications contained mutated microsatellite alleles (34%). In lichen planus, MSI(md-tissue) was seen in only four of 76 PCR products (5%) (P < 0.0001). The distribution of allelotypes in tumor cells from different disease stages was consistent with multilineage progression in five MF cases, as well as in the LyP/ALCL patient. Our results suggest that CTCL may evolve by multilineage progression and that tumor subclones in MF can be detected in early disease stages by mutation analysis of microsatellite DNA obtained from multiple microdissected areas. [source] MBP-1 is efficiently encoded by an alternative transcript of the ENO1 gene but post-translationally regulated by proteasome-dependent protein turnoverFEBS JOURNAL, Issue 20 2010Jrhau Lung The c-myc promoter-binding protein-1 (MBP-1) is a transcriptional suppressor of tumorigenesis and thought to be the product of alternative translation initiation of the ,-enolase (ENO1) transcript. In the present study, we cloned a 2552-bp novel cDNA with a putative coding sequence of MBP-1 and functionally examined its ability to encode the MBP-1 protein. Similarly to ENO1, the obtained MBP-1 was widely and differentially expressed in a variety of normal tissues and cancer cells. Experiments using MBP-1 promoter-driven luciferase reporter assays, biochemical cell fractionation followed by RT-PCR detection of the cytoplasmic mRNA, and transcription/translation-coupled reactions, consistently demonstrated that this novel transcript was alternatively transcribed from intron III of the ENO1 gene and was feasible for MBP-1 production. Hypoxia treatments significantly increased the transcriptional activation of the MBP-1 gene. Blocking the proteasomal degradation by MG132 stabilized the MBP-1 protein in cells. Compared with the translation efficiency for production of the MBP-1 protein, the MBP-1 transcript was 17.8 times more efficient than the ENO1 transcript. Thus, we suggest that this newly discovered transcript is a genuine template for the protein synthesis of MBP-1 in cells, and optimal expression of this gene in tumors may lead to effective clinical therapies for cancers. [source] An estrogen receptor , suppressor, microRNA-22, is downregulated in estrogen receptor ,-positive human breast cancer cell lines and clinical samplesFEBS JOURNAL, Issue 7 2010Jianhua Xiong Previous studies have suggested that microRNAs (miRNAs) may play important roles in tumorigenesis, but little is known about the functions of most miRNAs in cancer development. In the present study, we set up a cell-based screen using a luciferase reporter plasmid carrying the whole , 4.7 kb 3,-UTR of estrogen receptor , (ER,) mRNA cotransfected with a synthetic miRNA expression library to identify potential ER,-targeting miRNAs. Among all the miRNAs, miR-22 was found to repress robustly the luciferase signal in both HEK-293T and ER,-positive MCF-7 cells. Mutation of the target site was found to abrogate this repression effect of miR-22, whereas antagonism of endogenous miR-22 in MDA-MB-231 cells resulted in elevated reporter signals. We assessed the miR-22 expression patterns in five breast cancer cell lines and 23 clinical biopsies and revealed that there is a significant inverse association between the miR-22 levels and ER, protein expression. To evaluate the potential of miR-22 as a potential therapeutic intervention, we found that reduction of endogenous ER, protein levels and suppression of cancer cell growth could be achieved in MCF-7 cells by miR-22 overexpression in a way that can be recapitulated by the introduction of specific small interfering RNA against ER,. The phenomena can be rescued by the reintroduction of ER,. Taken together, our data indicate that miR-22 was frequently downregulated in ER,-positive human breast cancer cell lines and clinical samples. Direct involvement in the regulation of ER, may be one of the mechanisms through which miR-22 could play a pivotal role in the pathogenesis of breast cancer. [source] Epidermal growth factor receptor in relation to tumor development: EGFR-targeted anticancer therapyFEBS JOURNAL, Issue 2 2010Isamu Okamoto The discovery that signaling by the epidermal growth factor receptor (EGFR) plays a key role in tumorigenesis prompted efforts to target this receptor in anticancer therapy. Two different types of EGFR-targeted therapeutic agents were subsequently developed: mAbs, such as cetuximab and panitumumab, which target the extracellular domain of the receptor, thereby inhibiting ligand-dependent EGFR signal transduction; and small-molecule tyrosine kinase inhibitors, such as gefitinib and erlotinib, which target the intracellular tyrosine kinase domain of the EGFR. Furthermore, recent clinical and laboratory studies have identified molecular markers that have the potential to improve the clinical effectiveness of EGFR-targeted therapies. This minireview summarizes the emerging role of molecular profiling in guiding the clinical use of anti-EGFR therapeutic agents. [source] Sustained activation of ERK1/2 by NGF induces microRNA-221 and 222 in PC12 cellsFEBS JOURNAL, Issue 12 2009Kazuya Terasawa MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by inhibiting translation and/or inducing degradation of target mRNAs, and they play important roles in a wide variety of biological functions including cell differentiation, tumorigenesis, apoptosis and metabolism. However, there is a paucity of information concerning the regulatory mechanism of miRNA expression. Here we report identification of growth factor-regulated miRNAs using the PC12 cell line, an established model of neuronal growth and differentiation. We found that expression of miR-221 and miR-222 expression were induced by nerve growth factor (NGF) stimulation in PC12 cells, and that this induction was dependent on sustained activation of the extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway. Using a target prediction program, we also identified a pro-apototic factor, the BH3-only protein Bim, as a potential target of miR-221/222. Overexpression of miR-221 or miR-222 suppressed the activity of a luciferase reporter activity fused to the 3, UTR of Bim mRNA. Furthermore, overexpression of miR-221/222 decreased endogenous Bim mRNA expression. These results reveal that the ERK signal regulates miR-221/222 expression, and that these miRNAs might contribute to NGF-dependent cell survival in PC12 cells. [source] Gas6 and protein SFEBS JOURNAL, Issue 23 2006Vitamin K-dependent ligands for the Axl receptor tyrosine kinase subfamily Gas6 and protein S are two homologous secreted proteins that depend on vitamin K for their execution of a range of biological functions. A discrete subset of these functions is mediated through their binding to and activation of the receptor tyrosine kinases Axl, Sky and Mer. Furthermore, a hallmark of the Gas6,Axl system is the unique ability of Gas6 and protein S to tether their non receptor-binding regions to the negatively charged membranes of apoptotic cells. Numerous studies have shown the Gas6,Axl system to regulate cell survival, proliferation, migration, adhesion and phagocytosis. Consequently, altered activity/expression of its components has been detected in a variety of pathologies such as cancer and vascular, autoimmune and kidney disorders. Moreover, Axl overactivation can equally occur without ligand binding, which has implications for tumorigenesis. Further knowledge of this exquisite ligand,receptor system and the circumstances of its activation should provide the basis for development of novel therapies for the above diseases. [source] SAP-1 is a microvillus-specific protein tyrosine phosphatase that modulates intestinal tumorigenesisGENES TO CELLS, Issue 3 2009Hisanobu Sadakata SAP-1 (PTPRH) is a receptor-type protein tyrosine phosphatase (RPTP) with a single catalytic domain in its cytoplasmic region and fibronectin type III-like domains in its extracellular region. The cellular localization and biological functions of this RPTP have remained unknown, however. We now show that mouse SAP-1 mRNA is largely restricted to the gastrointestinal tract and that SAP-1 protein localizes to the microvilli of the brush border in gastrointestinal epithelial cells. The expression of SAP-1 in mouse intestine is minimal during embryonic development but increases markedly after birth. SAP-1-deficient mice manifested no marked changes in morphology of the intestinal epithelium. In contrast, SAP-1 ablation inhibited tumorigenesis in mice with a heterozygous mutation of the adenomatous polyposis coli gene. These results thus suggest that SAP-1 is a microvillus-specific RPTP that regulates intestinal tumorigenesis. [source] Different roles of proteolipids and 70-kDa subunits of V-ATPase in growth and death of cultured human cellsGENES TO CELLS, Issue 6 2003Hong Zhan Background: The vacuolar-type proton-translocating adenosine triphosphatase (V-ATPase) plays important roles in cell growth and tumour progression. V-ATPase is composed of two distinct structures, a hydrophilic catalytic cytosolic sector (V1) and a hydrophobic transmembrane sector (V0). The V1 sector is composed of 5,8 different subunits with the structure A3B3C1D1E1F1G1H1. The V0 sector is composed of 5 different subunits with the structure 1161381191166. The over-expression of 16-kDa proteolipid subunit of V-ATPase in the perinuclear region of the human adventitial fibroblasts promotes phenotypic modulation that contributes to neointimal formation and medial thickening. A relationship between oncogenicity and the expression of the 16-kDa proteolipid has also been suggested in human pancreatic carcinoma tissue. Results: We found that the mRNA levels of the 16-kDa proteolipid but not of the 70-kDa subunit of V-ATPase in human myofibroblasts were more abundant in serum-containing medium (MF(+) cells) than serum-free medium (MF(,) cells). In HeLa cells, the levels of mRNA and protein of the 16-kDa, 21-kDa or 70-kDa were clearly suppressed when the corresponding anti-sense oligonucleotides were administered to the culture medium. The growth rate and viability (mostly due to necrosis) of HeLa cells were reduced markedly by the 16-kDa and 21-kDa anti-sense, but little by the 70-kDa anti-sense, and not at all by any sense oligonucleotides. The localization of 16-kDa/21-kDa proteolipid subunits was different from that of the 70-kDa subunit in HeLa cells. Conclusion: These results suggest that the 16-kDa and 21-kDa proteolipid subunits of the V0 sector play crucial roles in growth and death of cultured human cells. Our results may provide new insights into the mechanism and therapeutic implications for vessel wall hyperplasia and tumorigenesis. [source] Genotypic and phenotypic classification of cancer: How should the impact of the two diagnostic approaches best be balanced?GENES, CHROMOSOMES AND CANCER, Issue 9 2010Petter Brandal Neoplastic tumors are traditionally named based on their differentiation (i.e., which normal cells and tissues they resemble) and bodily site. In recent years, knowledge about the genetic basis of tumorigenesis has grown rapidly, and the new information has in several instances been incorporated into the very definition of cancerous entities. The proper contribution of the diseases' phenotype and genotype to what they are called and how they are delineated from one another has rarely been subjected to explicit reasoning, however, nor is it often made clear whether existing naming practices are founded on ontological or utilitarian grounds. We look at several examples of how the new cytogenetic and molecular genetic understanding of tumorigenesis has impacted oncological nomenclature in a significant manner, but also at counterexamples where no similar change has taken place. In all likelihood, more and more neoplastic diseases will in the future be defined and named based on their pathogenesis rather than their phenotype, not least because effective and specific drug therapies directed against the molecular change at the very heart of oncogenesis will increasingly become available. The fact that this shift in emphasis is primarily guided by utilitarian considerations rather than any perception of acquired genetic changes as somehow being more ontologically "profound" or "important" in tumorigenesis, is as it should be; both the phenotype and the genotype of tumors are key parameters across most of oncology and are likely to be retained as the basis of coexisting disease classifications for as long as we can foresee. © 2010 Wiley-Liss, Inc. [source] Genome-wide scan identifies a copy number variable region at 3q26 that regulates PPM1L in APC mutation-negative familial colorectal cancer patientsGENES, CHROMOSOMES AND CANCER, Issue 2 2010L. F. Thean Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited form of colorectal cancer (CRC) caused by mutation in the adenomatous polyposis coli (APC) gene. However, APC mutations are not detected in 10,50% of FAP patients. We searched for a new cancer gene by performing genome-wide genotyping on members of an APC mutation-negative FAP variant family and ethnicity-matched healthy controls. No common copy number change was found in all affected members using the unaffected members and healthy controls as baseline. A 111 kb copy number variable (CNV) region at 3q26.1 was shown to have copy number loss in all eight polyps compared to matched lymphocytes of two affected members. A common region of loss in all polyps, which are precursors to CRC, is likely to harbor disease-causing gene in accordance to Knudsen's "two-hit" hypothesis. There is, however, no gene within the deleted region. A 2-Mb scan of the genomic region encompassing the deleted region identified PPM1L, coding for a novel serine-threonine phosphatase in the TGF-, and BMP signaling pathways. Real-time PCR analyses indicate that the 3,UTR of PPM1L transcript was down-regulated more than two-folds in all six polyps and tumors compared to matched mucosa of the affected member. This down-regulation was not observed in APC mutation-positive FAP patients. Our results suggest that the CNV region at 3q26 harbors an element that regulates the expression of an upstream candidate tumor suppressor, PPM1L, thus providing a novel mechanism for colorectal tumorigenesis in APC mutation-negative familial CRC patients. © 2009 Wiley-Liss, Inc. [source] Rearrangement of upstream sequences of the hTERT gene during cellular immortalizationGENES, CHROMOSOMES AND CANCER, Issue 11 2009Yuanjun Zhao Telomerase expression, resulting from transcriptional activation of the hTERT gene, allows cells to acquire indefinite proliferative potential during cellular immortalization and tumorigenesis. However, mechanisms of hTERT gene activation in many immortal cell lines and cancer cells are poorly understood. Here, we report our studies on hTERT activation using genetically related pairs of telomerase-negative (Tel,) and -positive (Tel+) fibroblast lines. First, whereas transiently transfected plasmid reporters did not recapitulate the endogenous hTERT promoter, the promoter in chromosomally integrated bacterial artificial chromosome (BAC) reporters was activated in a subset of Tel+ cells, indicating that activation of the hTERT promoter required native chromatin context and/or distal regulatory elements. Second, the hTERT gene, located near the telomere of chromosome 5p, was translocated in all three Tel+ cell lines but not in their parental precrisis cells and Tel, immortal siblings. The breakage points were mapped to regions upstream of the hTERT promoter, indicating that the hTERT gene was the target of these chromosomal rearrangements. In two Tel+ cell lines, translocation of the endogenous hTERT gene appeared to be the major mechanism of its activation as the activity of hTERT promoter in many chromosomally integrated BAC reporters, with intact upstream and downstream neighboring loci, remained relatively low. Therefore, our results suggest that rearrangement of upstream sequences is an important new mechanism of hTERT promoter activation during cellular immortalization. The chromosomal rearrangements likely occurred during cellular crisis and facilitated by telomere dysfunction. Such translocations allowed the hTERT promoter to escape from the native condensed chromatin environment. © 2009 Wiley-Liss, Inc. [source] Genomic imbalances in rhabdomyosarcoma cell lines affect expression of genes frequently altered in primary tumors: An approach to identify candidate genes involved in tumor developmentGENES, CHROMOSOMES AND CANCER, Issue 6 2009Edoardo Missiaglia Rhabdomyosarcomas (RMS) are the most common pediatric soft tissue sarcomas. They resemble developing skeletal muscle and are histologically divided into two main subtypes; alveolar and embryonal RMS. Characteristic genomic aberrations, including the PAX3 - and PAX7-FOXO1 fusion genes in alveolar cases, have led to increased understanding of their molecular biology. Here, we determined the effect of genomic copy number on gene expression levels through array comparative genomic hybridization (CGH) analysis of 13 RMS cell lines, confirmed by multiplex ligation-dependent probe amplification copy number analyses, combined with their corresponding expression profiles. Genes altered at the transcriptional level by genomic imbalances were identified and the effect on expression was proportional to the level of genomic imbalance. Extrapolating to a public expression profiling dataset for 132 primary RMS identified features common to the cell lines and primary samples and associations with subtypes and fusion gene status. Genes identified such as CDK4 and MYCN are known to be amplified, overexpressed, and involved in RMS tumorigenesis. Of the many genes identified, those with likely functional relevance included CENPF, DTL, MYC, EYA2, and FGFR1. Copy number and expression of FGFR1 was validated in additional primary material and found amplified in 6 out of 196 cases and overexpressed relative to skeletal muscle and myoblasts, with significantly higher expression levels in the embryonal compared with alveolar subtypes. This illustrates the ability to identify genes of potential significance in tumor development through combining genomic and transcriptomic profiles from representative cell lines with publicly available expression profiling data from primary tumors. © 2009 Wiley-Liss, Inc. [source] Novel mechanisms of gene disruption at the medulloblastoma isodicentric 17p11 breakpointGENES, CHROMOSOMES AND CANCER, Issue 2 2009Martin G. McCabe Isodicentric 17q is the most commonly reported chromosomal abnormality in medulloblastomas. Its frequency suggests that genes disrupted in medulloblastoma formation may play a role in tumorigenesis. We have previously identified two chromosome 17 breakpoint at a 1 Mb resolution. Our aims were to accurately map the position of these breakpoints and to identify mechanisms of gene disruption at this site. CGH with a custom tiling path genomic BAC array of chromosome 17 enriched with fosmids at the breakpoint regions was used to analyze a series of 45 medulloblastomas and three medulloblastoma-derived cell lines. In total, 17 of 45 medulloblastomas had an isodicentric 17q. Two breakpoint regions were identified and their positions were mapped. The array identified a more complex arrangement at the breakpoint than has been reported previously using lower resolution BAC arrays. The patterns observed indicated that dicentric chromosome formation occurs both via nonallelic homologous recombination between palindromically arranged low copy repeats (the previously accepted mechanism) and by recombination between nonidentical sequences. In addition, novel alternative structural alterations, a homozygous deletion and a duplication, were identified within the chromosome breakpoint region in two cases. At the resolution of the array, these structural alterations spanned the same genes as cases with dicentric 17q formation, implying that the disruption of genes at the chromosome breakpoint itself may be of greater biological significance than has previously been suspected. © 2008 Wiley-Liss, Inc. [source] Expression and mutational analysis of MET in human solid cancersGENES, CHROMOSOMES AND CANCER, Issue 12 2008Patrick C. Ma MET receptor tyrosine kinase and its ligand hepatocyte growth factor (HGF) regulate a variety of cellular functions, many of which can be dysregulated in human cancers. Activated MET signaling can lead to cell motility and scattering, angiogenesis, proliferation, branching morphogenesis, invasion, and eventual metastasis. We performed systematic analysis of the expression of the MET receptor and its ligand HGF in tumor tissue microarrays (TMA) from human solid cancers. Standard immunohistochemistry (IHC) and a computerized automated scoring system were used. DNA sequencing for MET mutations in both nonkinase and kinase domains was also performed. MET was differentially overexpressed in human solid cancers. The ligand HGF was widely expressed in both tumors, primarily intratumoral, and nonmalignant tissues. The MET/HGF likely is functional and may be activated in autocrine fashion in vivo. MET and stem cell factor (SCF) were found to be positively stained in the bronchioalevolar junctions of lung tumors. A number of novel mutations of MET were identified, particularly in the extracellular semaphorin domain and the juxtamembrane domain. MET-HGF pathway can be assayed in TMAs and is often overexpressed in a wide variety of human solid cancers. MET can be activated through overexpression, mutation, or autocrine signaling in malignant cells. Mutations in the nonkinase regions of MET might play an important role in tumorigenesis and tumor progression. MET would be an important therapeutic antitumor target to be inhibited, and in lung cancer, MET may represent a cancer early progenitor cell marker. © 2008 Wiley-Liss, Inc. [source] Chromosome 8 BAC array comparative genomic hybridization and expression analysis identify amplification and overexpression of TRMT12 in breast cancer,GENES, CHROMOSOMES AND CANCER, Issue 7 2007Virginia Rodriguez Genomic changes in chromosome 8 are commonly observed in breast cancer cell lines and tumors. To fine map such genomic changes by comparative genomic hybridization (CGH), a high resolution (100 kb) chromosome 8 array that can detect single copy changes was developed using Phi29 DNA polymerase amplified BAC (bacterial artificial chromosome) DNA. The BAC array CGH resolved the two known amplified regions (8q21 and 8q24) of a breast cancer cell line (SKBR3) into nine separate regions including six amplicons and three deleted regions, all of which were verified by Fluorescence in situ hybridization. The extent of the gain/loss for each region was validated by qPCR. CGH was performed with a total of 8 breast cancer cell lines, and common regions of genomic amplification/deletion were identified by segmentation analysis. A 1.2-Mb region (125.3,126.5 Mb) and a 1.0-Mb region (128.1,129.1 Mb) in 8q24 were amplified in 7/8 cell lines. A global expression analysis was performed to evaluate expression changes associated with genomic amplification/deletion: a novel gene, TRMT12 (at 125.5 Mb), amplified in 7/8 cell lines, showed highest expression in these cell lines. Further analysis by RT-qPCR using RNA from 30 breast tumors showed that TRMT12 was overexpressed >2 fold in 87% (26/30) of the tumors. TRMT12 is a homologue of a yeast gene encoding a tRNA methyltransferase involved in the posttranscriptional modification of tRNAPhe, and exploring the biological consequence of its altered expression, may reveal novel pathways in tumorigenesis. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat. Published 2007 Wiley-Liss, Inc. [source] Characterization of a 3;6 translocation associated with renal cell carcinomaGENES, CHROMOSOMES AND CANCER, Issue 4 2007Rebecca E. Foster The most frequent cause of familial clear cell renal cell carcinoma (RCC) is von Hippel,Lindau disease and the VHL tumor suppressor gene (TSG) is inactivated in most sporadic clear cell RCC. Although there is relatively little information on the mechanisms of tumorigenesis of clear cell RCC without VHL inactivation, a subset of familial cases harbors a balanced constitutional chromosome 3 translocation. To date nine different chromosome 3 translocations have been associated with familial or multicentric clear cell RCC; and in three cases chromosome 6 was also involved. To identify candidate genes for renal tumorigenesis we characterized a constitutional translocation, t(3;6)(q22;q16.1) associated with multicentric RCC without evidence of VHL target gene dysregulation. Analysis of breakpoint sequences revealed a 1.3-kb deletion on chromosome 6 within the intron of a 2 exon predicted gene (NT_007299.434). However, RT-PCR analysis failed to detect the expression of this gene in lymphoblast, fibroblast, or kidney tumor cell lines. No known genes were disrupted by the translocation breakpoints but several candidate TSGs (e.g., EPHB1, EPHA7, PPP2R3A RNF184, and STAG1) map within close proximity to the breakpoints. © 2007 Wiley-Liss, Inc. [source] Recurrent coamplification of cytoskeleton-associated genes EMS1 and SHANK2 with CCND1 in oral squamous cell carcinomaGENES, CHROMOSOMES AND CANCER, Issue 2 2006Kolja Freier Chromosomal band 11q13 is frequently amplified in oral squamous cell carcinoma (OSCC) and assumed to be critically involved in tumor initiation and progression by proto-oncogene activation. Though cyclin D1 (CCND1) is supposed to be the most relevant oncogene, several additional putative candidate genes are inside this chromosomal region, for which their actual role in tumorigenesis still needs to be elucidated. To characterize the 11q13 amplicon in detail, 40 OSCCs were analyzed by comparative genomic hybridization to DNA microarrays (matrix-CGH) containing BAC clones derived from chromosomal band 11q13. This high-resolution approach revealed a consistent amplicon about 1.7 Mb in size including the CCND1 oncogene. Seven BAC clones covering FGF3, EMS1, and SHANK2 were shown to be frequently coamplified inside the CCND1 amplicon. Subsequent analysis of tissue microarrays by FISH revealed amplification frequencies of 36.8% (88/239) for CCND1, 34.3% (60/175) for FGF3, 37.4% (68/182) for EMS1, and 36.3% (61/168) for SHANK2. Finally, quantitative mRNA expression analysis demonstrated consistent overexpression of CCND1 in all tumors and of EMS1 and SHANK2 in a subset of specimens with 11q13 amplification, but no expression of FGF3 in any of the cases. Our study underlines the critical role of CCND1 in OSCC development and additionally points to the functionally related genes EMS1 and SHANK2, both encoding for cytoskeleton-associated proteins, which are frequently coamplified with CCND1 and therefore could cooperatively contribute to OSCC pathogenesis. © 2005 Wiley-Liss, Inc. [source] A role for endogenous reverse transcriptase in tumorigenesis and as a target in differentiating cancer therapyGENES, CHROMOSOMES AND CANCER, Issue 1 2006Paola Sinibaldi-Vallebona An unexpected result emerging from completion of the genome sequencing project is that a large portion of mammalian genomes is constituted by retrotransposons. A large body of published data supports the conclusion that retrotransposons are biologically active elements and indicates that retrotransposition is an ongoing process in mammalian genomes. Retroelements can act as insertional mutagens altering the coding integrity of genes and, recently, have been found to also affect the expression of cellular genes at the epigenetic level: in this light, they are a potential threat in that these events can trigger the onset of several pathologies including cancer. Retroelement genes, and particularly the gene coding for reverse transcriptase (RT), are typically expressed at high levels in transformed cells and tumors. In recent work, we have found that drug-mediated inhibition of the endogenous RT activity, or silencing of expression of active retrotransposons of the LINE-1 family by RNA interference, down-regulate cell growth and induce the activation of differentiating functions in several cancer cell lines. Moreover, the inhibition of endogenous RT activity in vivo antagonizes the growth of human tumors in animal models. In this review, we discuss newly emerging concepts on the role of retrotransposons and suggest that an abnormally high level of the RT activity that they encode may contribute to the loss of control in the proliferation and differentiation programs typical of transformed cells. In this light, RT-coding elements may be regarded as promising targets in the development of novel, differentiation-inducing approaches to cancer therapy. © 2005 Wiley-Liss, Inc. [source] Profile of differentially expressed genes after transfer of chromosome 17 into the breast cancer cell line CAl51GENES, CHROMOSOMES AND CANCER, Issue 3 2005Christiane Klebig Previous studies have shown that transfer of chromosome 17 suppresses the tumorigenic phenotype of the breast cancer cell line CAL51, suggesting the presence of putative tumor suppressor genes on this chromosome. Suppression subtractive hybridization and oligonucleotide microarray analyses were performed to identify differentially expressed genes in nontumorigenic microcell hybrids, CAL/17-1 and CAL/17-3, when compared with CAL51 cells. In total, 263 differentially expressed transcripts were associated with these phenotypes. Of these, a high percentage is involved in various biological processes associated with tumorigenesis, including DNA-dependent regulation of transcription, regulation of cell cycle, signal transduction, and cell proliferation. Microarray analysis of selected chromosome 17 genes in a series of 25 human primary breast tumors showed associations with clinicopathologic parameters of the tumors. Of these genes, TOB1 (transducer of ERBB2) was selected for further expression analysis. Using RT-PCR and immunohistochemical staining of tissue microarrays, we could reveal a differential mRNA and protein expression of TOB1 in the majority of breast tumors and lymph node metastases compared with normal breast tissues, indicating a potential role of this protein in breast tumorigenesis. © 2005 Wiley-Liss, Inc. [source] Alterations of pre-mRNA splicing in cancerGENES, CHROMOSOMES AND CANCER, Issue 4 2005Zane Kalnin Recent genomewide analyses of alternative splicing (AS) indicate that up to 70% of human genes may have alternative splice forms, suggesting that AS together with various posttranslational modifications plays a major role in the production of proteome complexity. Splice-site selection under normal physiological conditions is regulated in the developmental stage in a tissue type-specific manner by changing the concentrations and the activity of splicing regulatory proteins. Whereas spliceosomal errors resulting in the production of aberrant transcripts rarely occur in normal cells, they seem to be an intrinsic property of cancer cells. Changes in splice-site selection have been observed in various types of cancer and may affect genes implicated in tumor progression (for example, CD44, MDM2, and FHIT) and in susceptibility to cancer (for example, BRCA1 and APC). Splicing defects can arise from inherited or somatic mutations in cis -acting regulatory elements (splice donor, acceptor and branch sites, and exonic and intronic splicing enhancers and silencers) or variations in the composition, concentration, localization, and activity of regulatory proteins. This may lead to altered efficiency of splice-site recognition, resulting in overexpression or down-regulation of certain splice variants, a switch in splice-site usage, or failure to recognize splice sites correctly, resulting in cancer-specific splice forms. At least in some cases, changes in splicing have been shown to play a functionally significant role in tumorigenesis, either by inactivating tumor suppressors or by gain of function of proteins promoting tumor development. Moreover, cancer-specific splicing events may generate novel epitopes that can be recognized by the host's immune system as cancer specific and may serve as targets for immunotherapy. Thus, the identification of cancer-specific splice forms provides a novel source for the discovery of diagnostic or prognostic biomarkers and tumor antigens suitable as targets for therapeutic intervention. © 2005 Wiley-Liss, Inc. [source] Mutational activation of the MAP3K8 protooncogene in lung cancerGENES, CHROMOSOMES AND CANCER, Issue 2 2004Adam Michael Clark The MAP3K8 protooncogene (Cot/Tpl-2) activates the MAP kinase, SAP kinase, and NF-,B signaling pathways. MAP3K8 mutations occur in the rat homologue, but activating mutations have yet to be identified in primary human tumors. We have identified MAP3K8 as a transforming gene from a human lung adenocarcinoma and characterized a 3, end mutation in the cDNA. In addition, we confirmed that the mutation occurs in the original lung tumor, and we screened a series of lung cancer cell lines to determine whether the MAP3K8 mutation is a common occurrence in lung tumorigenesis. The oncogene was isolated and identified with the NIH3T3 nude mouse tumorigenicity assay and cDNA library screening. The gene was analyzed by polymerase chain reaction (PCR), single-strand conformational polymorphism (SSCP), and 3,RACE for mutations. The mutation was localized to MAP3K8 exon 8 and confirmed in the primary tumor DNA. Both wild-type and mutant MAP3K8 cDNAs transformed NIH3T3 cells, but the transforming activity of the mutant was much greater than that of the wild type. PCR-SSCP screening of cell line cDNAs identified one silent polymorphism in cell line SK-LU-1. Although we were unable to find additional activating mutations, these data support a role for MAP3K8 activity in cellular transformation, but suggest that mutational activation of the gene is a rare event in lung cancer. © 2004 Wiley-Liss, Inc. [source] Order of genetic events is critical determinant of aberrations in chromosome count and structureGENES, CHROMOSOMES AND CANCER, Issue 4 2004Christine Fauth A sequential acquisition of genetic events is critical in tumorigenesis. A key step is the attainment of infinite proliferative potential. Acquisition of this immortalization requires the activation of telomerase in addition to other activities, including inactivation of TP53 and the retinoblastoma family of tumor-suppressor proteins. However, the importance of the order in which these genetic events occur has not been established. To address this question, we used a panel of normal mammary fibroblasts and endothelial cultures that were immortalized after transduction with the catalytic subunit of telomerase (hTERT) and a temperature-sensitive mutant of the SV40 large-tumor (tsLT) oncoprotein in different orders in early- and late-passage stocks. These lines were maintained in continuous culture for up to 90 passages, equivalent to >300 population doublings (PDs) post-explantation during 3 years of continuous propagation. We karyotyped the cultures at different passages. Cultures that received hTERT first followed by tsLT maintained a near-diploid karyotype for more than 150 PDs. However, in late-passage stocks (>200 PDs), metaphase cells were mostly aneuploid. In contrast, the reverse order of gene transduction resulted in a marked early aneuploidy and chromosomal instability, already visible after 50 PDs. These results suggest that the order of genetic mutations is a critical determinant of chromosome count and structural aberration events. © 2004 Wiley-Liss, Inc. [source] Genome-wide amplification and allelotyping of sporadic pituitary adenomas identify novel regions of genetic lossGENES, CHROMOSOMES AND CANCER, Issue 3 2003D. J. Simpson Through the use of a candidate gene approach, several previous studies have identified loss of heterozygosity (LOH) at putative tumor-suppressor gene (TSG) loci in sporadic pituitary tumors. This study reports a genome-wide allelotyping by use of 122 microsatellite markers in a large cohort of tumors, consisting of somatotrophinomas and non-functioning adenomas. Samples were first subject to prior whole genome amplification by primer extension pre-amplification (PEP) to circumvent limitations imposed by insufficient DNA for whole-genome analysis with this number of microsatellite markers. The overall mean frequency of loss in invasive tumors was significantly higher than that in their non-invasive counterparts (7 vs. 3% somatotrophinomas; 6 vs. 3% non-functioning adenomas, respectively). Analysis of the mean frequency of LOH, across all markers to individual chromosomal arms, identified 13 chromosomal arms in somatotrophinomas and 10 in non-functioning tumors, with LOH greater than the 99% upper confidence interval calculated for the rate of overall random allelic loss. In the majority of cases, these losses were more frequent in invasive tumors than in their non-invasive counterparts, suggesting these to be markers of tumor progression. Other regions showed similar frequencies of LOH in both invasive and non-invasive tumors, implying these to be early changes in pituitary tumorigenesis. This genome-wide study also revealed chromosomal regions where losses were frequently associated with an individual marker, for example, chromosome arm 1q (LOH > 30%). In some cases, these losses were subtype-specific and were found at a higher frequency in invasive tumors than in their non-invasive counterparts. Identification of these regions of loss provides the first preliminary evidence for the location of novel putative TSGs involved in pituitary tumorigenesis that are, in some cases, subtype-specific. This investigation provides an unbiased estimate of global aberrations in sporadic pituitary tumors as assessed by LOH analysis. The identification of multiple "hotspots" throughout the genome may be a reflection of an unstable chromatin structure that is susceptible to a deletion or epigenetic-mediated gene-silencing events. © 2003 Wiley-Liss, Inc. [source] APC/CTNNB1 (,-catenin) pathway alterations in human prostate cancersGENES, CHROMOSOMES AND CANCER, Issue 1 2002Amy V. Gerstein Genetic alterations serve as beacons for the involvement of specific pathways in tumorigenesis. It was previously shown that 5% of prostate tumors harbor CTNNB1 mutations, suggesting that this tumor type may involve a deregulated APC/CTNNB1 pathway. To explore this possibility further, we searched for mutations in genes implicated in this pathway in 22 samples that included cell lines, xenografts, and primary tumors. We identified seven alterations: two in CTNNB1, three in APC, and two in hTRCP1 (also known as BTRC) which controls the degradation of CTNNB1. Alterations in the CTNNB1 regulatory domain, APC, and hTRCP1 were mutually exclusive, consistent with their equivalent effects on CTNNB1 stability. These results suggest that CTNNB1 signaling plays a critical role in the development of a significant fraction of prostate cancers. Moreover, they provide the first evidence that hTRCP1 plays a role in human neoplasia. © 2002 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||||||||