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Sample records for identified apc germline

  1. APC germline mutations in families with familial adenomatous polyposis.

    PubMed

    De Queiroz Rossanese, Lillian Barbosa; De Lima Marson, Fernando Augusto; Ribeiro, José Dirceu; Coy, Claudio Saddy Rodrigues; Bertuzzo, Carmen Silvia

    2013-11-01

    Adenomatous polyposis coli (APC) germline mutations are responsible for the occurrence of familial adenomatous polyposis (FAP). Somatic mutations lead to malignant transformation of adenomas. In this context, considering the significance of APC germline mutations in FAP, we aimed to identify APC germline mutations. In the present study, 20 FAP patients were enrolled. The determination of APC germline mutations was performed using sequencing, and the mutations were compared with clinical markers (gender, age at diagnosis, smoking habits, TNM stage, Astler‑Coller stage, degree of differentiation of adenocarcinoma). The data were compared using the SPSS program, with the Fisher's exact test and χ2 test, considering α=0.05. According to the main results in our sample, 16 alleles with deleterious mutations (80% of the patients) were identified while 7 (35%) patients had no deleterious mutations. There was a predominance of nonsense (45% of the patients) and frameshift (20% of the patients) mutations. There was no statistical significance between the APC germline mutations identified and the clinical variables considered in our study. Only TNM stage was associated with the presence of deleterious mutations. Patients with deleterious mutations had an OR, 0.086 (IC=0.001-0.984); TNM stage I+II in comparison with III+IV, when compared with the patients with no deleterious mutations identified. In this context, as a conclusion, we demonstrated the molecular heterogeneity of APC germline mutations in FAP and the difficulty to perform molecular diagnostics in a Brazilian population, considering the admixed population analyzed.

  2. Prevalence of MYH germline mutations in Swiss APC mutation-negative polyposis patients.

    PubMed

    Russell, Anna M; Zhang, Jian; Luz, Judith; Hutter, Pierre; Chappuis, Pierre O; Berthod, Claudine Rey; Maillet, Philippe; Mueller, Hansjakob; Heinimann, Karl

    2006-04-15

    In 10-30% of patients with classical familial adenomatous polyposis (FAP) and up to 90% of those with attenuated (<100 colorectal adenomas; AFAP) polyposis, no pathogenic germline mutation in the adenomatous polyposis coli (APC) gene can be identified (APC mutation-negative). Recently, biallelic mutations in the base excision repair gene MYH have been shown to predispose to a multiple adenoma and carcinoma phenotype. This study aimed to (i) assess the MYH mutation carrier frequency among Swiss APC mutation-negative patients and (ii) identify phenotypic differences between MYH mutation carriers and APC/MYH mutation-negative polyposis patients. Seventy-nine unrelated APC mutation-negative Swiss patients with either classical (n=18) or attenuated (n=61) polyposis were screened for germline mutations in MYH by dHPLC and direct genomic DNA sequencing. Overall, 7 (8.9%) biallelic and 9 (11.4%) monoallelic MYH germline mutation carriers were identified. Among patients with a family history compatible with autosomal recessive inheritance (n=45), 1 (10.0%) out of 10 classical polyposis and 6 (17.1%) out of 35 attenuated polyposis patients carried biallelic MYH alterations, 2 of which represent novel gene variants (p.R171Q and p.R231H). Colorectal cancer was significantly (p<0.007) more frequent in biallelic mutation carriers (71.4%) compared with that of monoallelic and MYH mutation-negative polyposis patients (0 and 13.8%, respectively). On the basis of our findings and earlier reports, MYH mutation screening should be considered if all of the following criteria are fulfilled: (i) presence of classical or attenuated polyposis coli, (ii) absence of a pathogenic APC mutation, and (iii) a family history compatible with an autosomal recessive mode of inheritance. Copyright (c) 2005 Wiley-Liss, Inc.

  3. Double germline mutations in APC and BRCA2 in an individual with a pancreatic tumor.

    PubMed

    Goehringer, Caroline; Sutter, Christian; Kloor, Matthias; Gebert, Johannes; Slater, Emily P; Keller, Monika; Treiber, Irmgard; Ganschow, Petra; Kadmon, Martina; Moog, Ute

    2017-04-01

    We report on three brothers affected by pancreatic tumors, all due to different causes, including mutations associated with two different cancer predisposition syndromes in the same individual. In the index patient a germline mutation both in the APC and BRCA2 gene was identified while one affected brother showed the BRCA2 mutation only and another brother is supposed to have developed pancreatic cancer due to multiple non-genetic risk factors. We outline the impact of a double germline mutation in two tumor predisposition genes in one individual and proven heterogeneity of multiple cases of pancreatic tumors in one family. With the growing implementation of next generation sequence based panel testing for multiple genes involved in tumor predisposition syndromes, relevant variants in two (or more) genes will be found more frequently. This family illustrates the importance of family studies, especially when using gene panel tests.

  4. A novel pathogenic single nucleotide germline deletion in APC gene in a four generation Chinese family with familial adenomatous polyposis.

    PubMed

    Zhang, Zhao; Liang, Shengyun; Wang, Dan; Liang, Shengran; Li, Yuwei; Wang, Bingjie; Jiang, Tao; Zhao, Guoru; Zhang, Xipeng; Banerjee, Santasree

    2017-09-27

    Familial adenomatous polyposis (FAP) is an autosomal dominant precancerous condition which is associated with germline mutations of the APC gene. Clinically, FAP is characterized by the development of multiple colorectal adenomas or polyps which finally result in colorectal cancer by the 40 years age of the patient, if no surgical interventions have been undertaken. In this study, we present a clinical molecular study of a four generation Chinese family with FAP. Diagnosis of FAP was made on the basis of clinical manifestations, family history and medical (colonoscopy and histopathology) records. Genetic screening of the proband and all affected family members were performed by targeted next-generation sequencing and confirmatory Sanger sequencing. Targeted next generation sequencing identified a germline novel heterozygous single nucleotide deletion [c.3418delC; p.Pro1140Leufs*25] in exon18 of APC gene, which segregated with the FAP phenotypes in the proband and in all the affected family members whereas absent in unaffected family members as well as in normal healthy controls of same ethnic origin. Our present study expands the mutational spectrum of APC gene and provides evidence to understand the function of APC gene in FAP.

  5. A novel exon duplication event leading to a truncating germ-line mutation of the APC gene in a familial adenomatous polyposis family.

    PubMed

    McCart, Amy; Latchford, Andrew; Volikos, Emmanouil; Rowan, Andrew; Tomlinson, Ian; Silver, Andrew

    2006-01-01

    Familial Adenomatous Polyposis (FAP) is an autosomal dominant condition predisposing to multiple adenomatous polyps of the colon. FAP patients frequently carry heterozygous mutations of the APC tumour suppressor gene. Affected individuals from a cohort of FAP families (n=22), where no germ-line APC mutation was detected by direct sequencing, were analysed by Multiplex Ligation-dependent Probe Amplification (MLPA). MLPA identified a previously unreported APC mutation involving duplication of exon 4. Subsequent analysis of cDNA from affected family members revealed expression of mutant mRNA species containing two copies of exon 4, resulting in a frameshift and premature stop codon. Bioinformatic analysis of the relevant APC genomic segment predicted a role for homologous recombination possibly involving Alu repeats in the generation of this genotype. Our results highlight the importance of MLPA as an adjunct to exon-by-exon sequencing in identifying infrequent mutational events in cancer predisposing genes.

  6. Novel and reported APC germline mutations in Chinese patients with familial adenomatous polyposis.

    PubMed

    Zhang, Shujie; Qin, Haisong; Lv, Weigang; Luo, Shiyu; Wang, Jin; Fu, Chunyun; Ma, Ruiyu; Shen, Yiping; Chen, Shaoke; Wu, Lingqian

    2016-02-15

    Familial adenomatous polyposis (FAP) is mainly caused by germline mutations in the adenomatous polyposis coli (APC) gene. This study aimed to detect pathogenic variants in five Chinese FAP families and review all previously reported pathogenic variants of APC gene in Chinese population. Five non-consanguineous FAP families and 100 unrelated ethnicity-matched controls were included in the study. Sanger sequencing was performed to screen for APC coding and splicing variants. Chinese and English literature on APC germline mutations were reviewed to compile the mutation spectrum of APC gene in Chinese FAP patients. One pathogenic variant was detected in each family for the five pedigrees we tested. Three variants (c.3183_3187delACAAA, c.2626C>T and c.1312+1G>A) were previously reported as pathogenic. The other two variants were novel: c.794_795insG/p.Val266SerfsTer11 and c.2142_2143insG/p.His715AlafsTer19. They are absent from public databases (1000 Genomes, dbSNP, ESP and ExAC) and 100 normal controls, and are classified as pathogenic based on the new ACMG/AMP variant classification guidelines. Literature review and current study revealed a total of 82 different pathogenic variants from 127 Chinese FAP families. Among these families, 83 families had frameshift variants (65.35%), 26 with nonsense variants (20.47%), six with splice site variants (4.72%), three with missense variants (2.36%) and nine with large deletion or duplication variants (7.09%). Apart from the two previously reported mutation hotspots c.3927_3931delAAAGA (20.47%) and c.3183_3187delACAAA (7.09%), c.847C>T/p.Arg283Ter variant occurred with a frequency of 3.15% (4 out of 127) in Chinese FAP patients. We reported two novel pathogenic variants. The comprehensive compilation of variants and comparison revealed largely similar mutation spectrum between Chinese and Western patient populations. Some unique features noticed in Chinese patient population may help to better understand the pathogenesis of FAP

  7. Evidence for genetic predisposition to desmoid tumours in familial adenomatous polyposis independent of the germline APC mutation

    PubMed Central

    Sturt, N J H; Gallagher, M C; Bassett, P; Philp, C R; Neale, K F; Tomlinson, I P M; Silver, A R J; Phillips, R K S

    2004-01-01

    Background: Many patients with familial adenomatous polyposis (FAP) die from desmoid tumours which can arise spontaneously but often appear to be surgically induced by prophylactic colectomy. FAP results from germline adenomatous polyposis coli (APC) gene mutations and desmoids arise following biallelic APC mutation, with one change usually occurring distal to the second β-catenin binding/degradation repeat of the gene (3′ to codon 1399). We have suggested that because families with germline mutations in this region already have the requisite change, they are more likely to develop desmoids. However, there are families with 5′ germline mutations where desmoids are common. Patients and methods: We examined desmoid risk dependent on germline APC mutation, sex, history of abdominal surgery, and family history in FAP patients from the St Mark’s Hospital Polyposis Registry. Results: Overall desmoid prevalence was 15%. Desmoids tended to cluster in susceptible individuals, irrespective of the germline APC mutation. Independent predictors of increased desmoid risk were: germline mutation distal to codon 1399; any family history of disease; and a strong family history of desmoids. A family history of multiple desmoids (>1) increased an individual’s own risk of multiplicity. Females had twice the odds of developing desmoids compared with males. There was no significant interaction between any of the three explanatory variables. Conclusions: Our results indicate the influence of unknown genetic factors independent of APC in susceptibility to desmoid tumours in FAP. The data have implications in terms of clinical management of FAP patients and assessing the balance between chemoprevention and prophylactic colectomy. PMID:15542524

  8. A novel pathogenic splice acceptor site germline mutation in intron 14 of the APC gene in a Chinese family with familial adenomatous polyposis

    PubMed Central

    Zhao, Guoru; Hu, Yuan; Liang, Shengran; Zhang, Xipeng

    2017-01-01

    Familial adenomatous polyposis (FAP) is an autosomal dominant precancerous condition, clinically characterized by the presence of multiple colorectal adenomas or polyps. Patients with FAP has a high risk of developing colorectal cancer (CRC) from these colorectal adenomatous polyps by the mean age of diagnosis at 40 years. Germline mutations of the APC gene cause familial adenomatous polyposis (FAP). Colectomy has recommended for the FAP patients with significant polyposis. Here, we present a clinical molecular study of a four generation Chinese family with FAP. Clinical diagnosis of FAP has been done according to the phenotype, family history and medical records. Patient's blood samples were collected and genomic DNA was extracted. In order to identify the pathogenic mutation underlying the disease phenotype targeted next-generation sequencing and confirmatory sanger sequencing has undertaken. Targeted next generation sequencing identified a novel heterozygous splice-acceptor site mutation [c.1744-1G>A] in intron 14 of APC gene, which is co-segregated with the FAP phenotypes in the proband and amongst all the affected family members. This mutation is not present in unaffected family members and in normal healthy controls of same ethnic origin. According to the LOVD database for Chinese colorectal cancer patients, in Chinese population, 60% of the previously reported APC gene mutations causes FAP, are missense mutations. This novel splice-acceptor site mutation causing FAP in this Chinese family expands the germline mutation spectrum of the APC gene in the Chinese population. PMID:28423518

  9. A novel pathogenic splice acceptor site germline mutation in intron 14 of the APC gene in a Chinese family with familial adenomatous polyposis.

    PubMed

    Wang, Dan; Liang, Shengyun; Zhang, Zhao; Zhao, Guoru; Hu, Yuan; Liang, Shengran; Zhang, Xipeng; Banerjee, Santasree

    2017-03-28

    Familial adenomatous polyposis (FAP) is an autosomal dominant precancerous condition, clinically characterized by the presence of multiple colorectal adenomas or polyps. Patients with FAP has a high risk of developing colorectal cancer (CRC) from these colorectal adenomatous polyps by the mean age of diagnosis at 40 years. Germline mutations of the APC gene cause familial adenomatous polyposis (FAP). Colectomy has recommended for the FAP patients with significant polyposis. Here, we present a clinical molecular study of a four generation Chinese family with FAP. Clinical diagnosis of FAP has been done according to the phenotype, family history and medical records. Patient's blood samples were collected and genomic DNA was extracted. In order to identify the pathogenic mutation underlying the disease phenotype targeted next-generation sequencing and confirmatory sanger sequencing has undertaken. Targeted next generation sequencing identified a novel heterozygous splice-acceptor site mutation [c.1744-1G>A] in intron 14 of APC gene, which is co-segregated with the FAP phenotypes in the proband and amongst all the affected family members. This mutation is not present in unaffected family members and in normal healthy controls of same ethnic origin. According to the LOVD database for Chinese colorectal cancer patients, in Chinese population, 60% of the previously reported APC gene mutations causes FAP, are missense mutations. This novel splice-acceptor site mutation causing FAP in this Chinese family expands the germline mutation spectrum of the APC gene in the Chinese population.

  10. NRAS germline variant G138R and multiple rare somatic mutations on APC in colorectal cancer patients in Taiwan by next generation sequencing.

    PubMed

    Chang, Pi-Yueh; Chen, Jinn-Shiun; Chang, Nai-Chung; Chang, Shih-Cheng; Wang, Mei-Chia; Tsai, Shu-Hui; Wen, Ying-Hao; Tsai, Wen-Sy; Chan, Err-Cheng; Lu, Jang-Jih

    2016-06-21

    Colorectal cancer (CRC) arises from mutations in a subset of genes. We investigated the germline and somatic mutation spectrum of patients with CRC in Taiwan by using the AmpliSeq Cancer Hotspot Panel V2. Fifty paired freshly frozen stage 0-IV CRC tumors and adjacent normal tissue were collected. Blood DNA from 20 healthy donors were used for comparison of germline mutations. Variants were identified using an ion-torrent personal genomic machine and subsequently confirmed by Sanger sequencing or pyrosequencing. Five nonsynonymous germline variants on 4 cancer susceptible genes, CDH1, APC, MLH1, and NRAS, were observed in 6 patients with CRC (12%). Among them, oncogene NRAS G138R variant was identified as having a predicted damaging effect on protein function, which has never been reported by other laboratories. CDH1 T340A variants were presented in 3 patients. The germline variants in the cancer patients differed completely from those found in asymptomatic controls. Furthermore, a total of 56 COSMIC and 21 novel somatic variants distributed in 20 genes were detected in 44 (88%) of the CRC samples. High inter- and intra-tumor heterogeneity levels were observed. Nine rare variants located in the β-catenin binding region of the APC gene were discovered, 7 of which could cause amino acid frameshift and might have a pathogenic effect. In conclusion, panel-based mutation detection by using a high-throughput sequencing platform can elucidate race-dependent cancer genomes. This approach facilitates identifying individuals at high risk and aiding the recognition of novel mutations as targets for drug development.

  11. Type 1 serrated polyposis represents a predominantly female disease with a high prevalence of dysplastic serrated adenomas, without germline mutation in MUTYH, APC, and PTEN genes

    PubMed Central

    Petronio, Marco; Pinson, Stephane; Walter, Thomas; Joly, Marie-Odile; Hervieu, Valerie; Forestier, Julien

    2015-01-01

    Aim The aim of this article is to clarify the epidemiologic, clinical, endoscopic, biological and genetic characteristics of type 1 serrated polyposis patients. Patients and methods Consecutive patients responding to the WHO definition of type 1 serrated polyposis in one reference center for polyposis patients accepted genetic counseling. Detailed data on previous endoscopies, histology, and life habits were recorded, after informed consent, germline analysis of MUTYH, APC, and PTEN germline mutations. Molecular biology was tested on available fixed tissue from different lesion types. Results We included 29 patients (mean age 53.5 years, 21 women (72.4%)), four with a personal history of colorectal cancer (CRC), with a mean of 11.6 SSAs, with associated hyperplastic polyps in 93.1% and adenomas in 82.8%. SSAs showed no dysplasia in 46.9% of lesions (three of 29 patients), LGD in 51.9% (22/29 patients), and HGD in 1.2% (four of 29 patients). Dysplasia was more frequent in proximal SSAs and in women. Colectomy 15 patients (51.7%), upper digestive neoplasms: eight patients (27.5%); smokers: 24 patients (82.8%); family history of CRC: 16 patients (55.2%). Biology: MSI-H phenotype in one SSA, V600E BRAF mutation in 95% of SSAs; MGMT hypermethylation in three of 17 SSAs. No germline mutation was detected in MYH, APC or PTEN genes. Conclusion Type 1 serrated polyposis corresponds to a majority of women, with a high prevalence of smokers, a high prevalence of dysplastic serrated adenomas, particularly in females, without identified germline mutation in targeted predisposing genes. PMID:27087961

  12. Maternal mosaicism for a second mutational event--a novel deletion--in a familial adenomatous polyposis family harboring a new germ-line mutation in the alternatively spliced-exon 9 region of APC.

    PubMed

    Davidson, Sima; Leshanski, Lucy; Rennert, Gad; Eidelman, Shmuel; Amikam, Dorit

    2002-01-01

    Familial Adenomatous Polyposis (FAP) is an autosomal dominant heritable disorder caused by germ-line mutations in the APC gene. To date, more than 300 germ-line mutations within this gene have been described. Using PCR, SSCP and DNA sequencing, we have identified a new mutation in the alternatively spliced region of exon 9 (1042C-->T), which results in a stop signal. This mutation manifested an aggressive form of FAP with onset of symptoms in one proband at age 17. Our results differ from reported exon 9 mutations in the spliced-out portion of the gene manifesting an attentuated form of FAP (AAPC) [Varesco et al 1994; van der Luijt et al. 1995; Curia et al. 1998; Young et al. 1998]. When analyzing this family, we encountered a mutant FAP gene which had undergone a second mutational event, a deletion. In addition to linkage analysis, both the occurrence of the two exon 9 mutation-carrier siblings, of which one is affected, harboring the same novel deletion in one generation of this family, and its absence in both parents indicates the existence of maternal germ-line mosaicism for cells bearing the latter second mutational event. Our study is only the second report of parental mosaicism in the APC gene. Copyright 2001 Wiley-Liss, Inc.

  13. Clinical Characteristics of Multiple Colorectal Adenoma Patients Without Germline APC or MYH Mutations.

    PubMed

    Tieu, Alan H; Edelstein, Daniel; Axilbund, Jennifer; Romans, Katharine E; Brosens, Lodewijk A; Wiley, Elizabeth; Hylind, Linda; Giardiello, Francis M

    2016-08-01

    Patients with multiple colorectal adenomas (MCRA) without genetic cause are increasingly being diagnosed. The characteristics and natural history of this condition are not well studied. Twenty-seven patients with MCRA, with cumulatively 10 to 99 colorectal adenomas and without deleterious mutations of APC or MYH genes, were investigated. Results of colonoscopies with a mean follow-up of 4.9 years (range, 0 to 27 y) were evaluated. Findings from esophagogastroduodenoscopy and extracolonic manifestations were assessed. The mean age at polyp diagnosis and MCRA diagnosis was 47.8±13.1 years (range, 21 to 72 y) and 50.4±14.6 years (range, 21 to 72 y), respectively. In 22% of patients another family member had MCRA. At first colonoscopy, the mean number of adenomas was 35.0±35.9 (range, 0 to 99). Serrated polyps were rare. Esophagogastroduodenoscopy revealed 47% of patients had upper tract neoplasia. Patients with upper tract findings were diagnosed with MCRA at significantly younger mean age than those without findings, P<0.05. Eighteen patients (67%) underwent colectomy with a mean time from diagnosis of MCRA of 3.1±1.3 years. After surgery, surveyed patients developed recurrent adenomas in retained colorectum. Nine patients (33%) had extracolonic cancers. MCRA patients have a similar clinicopathologic phenotype to known syndromes of attenuated adenomatous polyposis and the majority have need for colectomy. The management of MCRA patients and families should parallel that of attenuated familial adenomatous polyposis and MUTYH-associated polyposis including surveillance of the upper tract.

  14. Germline mosaicism in Rett syndrome identified by prenatal diagnosis.

    PubMed

    Mari, F; Caselli, R; Russo, S; Cogliati, F; Ariani, F; Longo, I; Bruttini, M; Meloni, I; Pescucci, C; Schurfeld, K; Toti, P; Tassini, M; Larizza, L; Hayek, G; Zappella, M; Renieri, A

    2005-03-01

    Rett syndrome is an X-linked neurodevelopmental dominant disorder that affects almost exclusively girls. The vast majority of cases are sporadic and are caused by de novo mutations in the MECP2 gene, located in Xq28. Only few familial cases have been reported: in four cases, the mother was an asymptomatic carrier and in other four cases, the germline mosaicism in the mother was postulated. Owing to the above reported cases of germline mosaicism, we decided to offer prenatal diagnosis to all expectant mothers with a Rett daughter despite the absence of the causative mutation in parents' blood. We describe here the outcome of the first nine cases of prenatal diagnosis followed by our center. In eight cases, the fetus did not carry the mutation. In one case, the female fetus did carry the same mutation of the affected sister. The couple decided to interrupt the pregnancy and to devolve fetal tissues for research purposes. Our results indicate that prenatal diagnosis should be proposed to all couples with a Rett daughter, even when the mutation is apparently de novo. Moreover, one positive prenatal test among the first nine cases indicates that germline mosaicism may be seriously considered for the assessment of recurrence risk during genetic counseling.

  15. ALLELE-SPECIFIC EXPRESSION OF APC IN ADENOMATOUS POLYPOSIS FAMILIES

    PubMed Central

    Castellsagué, Ester; González, Sara; Guinó, Elisabet; Stevens, Kristen N.; Borràs, Ester; Raymond, Victoria M.; Lázaro, Conxi; Blanco, Ignacio; Gruber, Stephen B.; Capellá, Gabriel

    2010-01-01

    Backgound & Aims Germline mutations of the APC gene are the pathogenic cause of most cases of familial adenomatous polyposis (FAP) and a lesser proportion of attenuated FAP (AFAP). Systematic analysis of APC at the RNA level may provide insight into the pathogenicity of identified mutations and uncover the molecular basis of FAP/AFAP in families without identifiable mutations. Here, we analyzed the prevalence of imbalances in the allelic expression of APC in polyposis families with germline mutations in the gene and without detectable mutations in APC or and MUTYH. Methods Allele-specific expression (ASE) was determined by single nucleotide primer extension using an exon 11 polymorphism as an allele-specific marker. In total, 52 APC-mutation-positive (36 families) and 24 APC/MUTYH-mutation-negative (23 families) informative patients were analyzed. Seventy-six controls were also included. Results Of the APC-mutation-positive families, most of those in which the mutation was located before the last exon of the gene (12 of 14) showed ASE imbalance, which is consistent with a mechanism of nonsense-mediated decay (NMD). Of the APC/MUTYH mutation-negative families, two (9%) showed ASE imbalance as a hallmark of the putative pathogenic cause of the disease. Normal allele expression was restored after treatment of short-term cultured lymphocytes with puromycin, supporting the NMD hypothesis. Conclusions ASE analysis may be an indicator of pathogenicity for some cases of FAP and AFAP in which APC mutations are not found. ASE might also be useful for prioritizing the order in which different areas of APC should be tested. Our results underline the importance of RNA-level studies in molecular diagnosis of FAP. PMID:20434453

  16. Small RNA in situ hybridization in Caenorhabditis elegans, combined with RNA-seq, identifies germline-enriched microRNAs☆

    PubMed Central

    Yun, Sijung; Lee, Chin-Yung; Bennett, Karen L.

    2016-01-01

    Over four hundred different microRNAs (miRNAs) have been identified in the genome of the model organism the nematode Caenorhabditis elegans. As the germline is dedicated to the preservation of each species, and almost half of all the cells in an adult nematode are germline, it is likely that regulatory miRNAs are important for germline development and maintenance. In C. elegans the miR35 family has strong maternal effects, contributing to normal embryogenesis and to adult fecundity. To determine whether any particular miRNAs are greatly enriched in the C. elegans germline we used RNA-seq to compare the miRNA populations in several germline-defective strains of adult C. elegans worms, including glp-4(germline proliferation-4), glh-1(germline helicase-1) and dcr-1(dicer-1). Statistical analyses of RNA-seq comparisons identified 13 miRNAs that are germline-enriched, including seven members of the well-studied miR35 family that were reduced as much as 1000-fold in TaqMan qRT PCR miRNA assays. Along with the miR35s, six others: miR-56 (a member of the miR51 family),−70, −244, −260 , −788 and −4813, none of which previously considered as such, were also identified by RNA-seq as germline-enriched candidates. We went on to develop a successful miRNA in situ hybridization protocol for C. elegans, revealing miR35s specifically concentrate during oogenesis in the pachytene region of the gonad, and persist throughout early embryogenesis, while in adult animals neither let-7 nor miR-228 has a germline-bias. PMID:27521456

  17. Reduced expression of APC-1B but not APC-1A by the deletion of promoter 1B is responsible for familial adenomatous polyposis

    PubMed Central

    Yamaguchi, Kiyoshi; Nagayama, Satoshi; Shimizu, Eigo; Komura, Mitsuhiro; Yamaguchi, Rui; Shibuya, Tetsuo; Arai, Masami; Hatakeyama, Seira; Ikenoue, Tsuneo; Ueno, Masashi; Miyano, Satoru; Imoto, Seiya; Furukawa, Yoichi

    2016-01-01

    Germline mutations in the tumor suppressor gene APC are associated with familial adenomatous polyposis (FAP). Here we applied whole-genome sequencing (WGS) to the DNA of a sporadic FAP patient in which we did not find any pathological APC mutations by direct sequencing. WGS identified a promoter deletion of approximately 10 kb encompassing promoter 1B and exon1B of APC. Additional allele-specific expression analysis by deep cDNA sequencing revealed that the deletion reduced the expression of the mutated APC allele to as low as 11.2% in the total APC transcripts, suggesting that the residual mutant transcripts were driven by other promoter(s). Furthermore, cap analysis of gene expression (CAGE) demonstrated that the deleted promoter 1B region is responsible for the great majority of APC transcription in many tissues except the brain. The deletion decreased the transcripts of APC-1B to 39–45% in the patient compared to the healthy controls, but it did not decrease those of APC-1A. Different deletions including promoter 1B have been reported in FAP patients. Taken together, our results strengthen the evidence that analysis of structural variations in promoter 1B should be considered for the FAP patients whose pathological mutations are not identified by conventional direct sequencing. PMID:27217144

  18. Molecular analysis of the APC and MUTYH genes in Galician and Catalonian FAP families: a different spectrum of mutations?

    PubMed Central

    Gómez-Fernández, Nuria; Castellví-Bel, Sergi; Fernández-Rozadilla, Ceres; Balaguer, Francesc; Muñoz, Jenifer; Madrigal, Irene; Milà, Montserrat; Graña, Begoña; Vega, Ana; Castells, Antoni; Carracedo, Ángel; Ruiz-Ponte, Clara

    2009-01-01

    Background Familial adenomatous polyposis (FAP) is an autosomal dominant-inherited colorectal cancer syndrome, caused by germline mutations in the APC gene. Recently, biallelic mutations in MUTYH have also been identified in patients with multiple colorectal adenomas and in APC-negative patients with FAP. The aim of this work is therefore to determine the frequency of APC and MUTYH mutations among FAP families from two Spanish populations. Methods Eighty-two unrelated patients with classical or attenuated FAP were screened for APC germline mutations. MUTYH analysis was then conducted in those APC-negative families and in 9 additional patients from a previous study. Direct sequencing, SSCP analysis and TaqMan genotyping were used to identify point and frameshift mutations, meanwhile large rearrangements in the APC gene were screened by multiplex ligation-dependent probe amplification (MLPA). Results APC germline mutations were found in 39% of the patients and, despite the great number of genetic variants described so far in this gene, seven new mutations were identified. The two hotspots at codons 1061 and 1309 of the APC gene accounted for 9,4% of the APC-positive families, although they were underrepresented in Galician samples. The deletion at codon 1061 was not found in 19 APC-positive Galician patients but represented 23% of the Catalonian positive families (p = 0,058). The same trend was observed at codon 1309, even though statistical analysis showed no significance between populations. Twenty-four percent of the APC-negative patients carried biallelic MUTYH germline mutations, and showed an attenuated polyposis phenotype generally without extracolonic manifestations. New genetic variants were found, as well as the two hotspots already reported (p.Tyr165Cys and p.Gly382Asp). Conclusion The results we present indicate that in Galician patients the frequency of the hotspot at codon 1061 in APC differs significantly from the Catalonian and also other Caucasian

  19. A Novel Germline Mutation in Exon 15 of the APC Gene in Attenuated Familial Adenomatous Polyposis: A Report of Two Cases

    PubMed Central

    Jahng, Jaehoon; Yoon, Sang Jin

    2013-01-01

    Attenuated familial adenomatous polyposis (AFAP) is a variant of familial adenomatous polyposis with fewer than one hundred colorectal polyps and a later age of onset of the cancer. Here, we report two cases of AFAP within family members. Each patient demonstrated the same novel germ line mutation in exon 15 of the adenomatous polyposis coli (APC) gene and was successfully managed with sulindac after refusal to perform colectomy: a 23-year-old man with incidentally diagnosed gastric adenoma and fundic gland polyps underwent colonoscopy, and fewer than 100 colorectal polyps were found; a 48-year-old woman who happened to be the mother of the 23-year-old man also showed fewer than 100 colorectal polyps on colonoscopy. Genetic analysis revealed a novel frameshift mutation in exon 15 of the APC gene. The deletion of adenine-guanine with the insertion of thymine in c.3833-3834 resulted in the formation of stop codon 1,287 in both patients. The patients were treated with sulindac due to their refusal to undergo colectomy. The annual follow-up upper endoscopy and colonoscopy in the following 2 years revealed significant regression of the colorectal polyps in both patients. PMID:23423322

  20. Bacterial cytoplasmic display platform Retained Display (ReD) identifies stable human germline antibody frameworks.

    PubMed

    Beasley, Matthew D; Niven, Keith P; Winnall, Wendy R; Kiefel, Ben R

    2015-05-01

    Conventional antibody surface display requires fusion protein export through at least one cellular membrane, constraining the yield and occasioning difficulties in achieving scaled production. To circumvent this limitation, we developed a novel cytoplasmic display platform, Retained Display (ReD), and used it to screen for human scFv frameworks that are highly soluble and stable in the bacterial cytoplasm. ReD, based on the retention of high-molecular weight complexes within detergent-permeabilized Escherichia coli, enabled presentation of exogenous targets to antibodies that were expressed and folded in the cytoplasm. All human λ and κ light chain family genes were expressed as IGHV3-23 fusions. Members of the λ subfamilies 1, 3 and 6 were soluble cytoplasmic partners of IGHV3-23. Contrary to previous in vivo screens for soluble reduced scFvs, the pairings identified by ReD were identical to the human germline sequences for the framework, CDR1 and CDR2 regions. Using the most soluble scFv scaffold identified, we demonstrated tolerance to CDR3 diversification and isolated a binding scFv to an exogenous protein target. This screening system has the potential to rapidly produce antibodies to target threats such as emerging infectious diseases and bioterror agents.

  1. Evidence for a novel exon in the coding region of the adenomatous polyposis coli (APC) gene

    SciTech Connect

    Xia, Ling; St. Denis, K.A.; Bapat, B.

    1995-08-10

    Germline mutations of the tumor suppressor gene APC cause familial adenomatous polyposis. Somatic APC alterations are involved in several sporadic neoplasma, including colorectal, duodenal, gastric, and esophageal carcinoma. The APC mRNA is encoded by 15 exons. Additional transcripts have been reported, due to alternative splicing of coding as well as noncoding regions. Two mRNA isoforms occur due to a deletion of exon 7 or a partial deletion of exon 9. We have identified a novel exon, flanked by APC exons 10 and 11, which is expressed as an alternatively transcribed product of the gene. Further, we have shown that the novel exon consists of a heptad repeat motif and is conserved across species. 18 refs., 2 figs.

  2. Multiple colorectal adenomas, classic adenomatous polyposis, and germ-line mutations in MYH.

    PubMed

    Sieber, Oliver M; Lipton, Lara; Crabtree, Michael; Heinimann, Karl; Fidalgo, Paulo; Phillips, Robin K S; Bisgaard, Marie-Luise; Orntoft, Torben F; Aaltonen, Lauri A; Hodgson, Shirley V; Thomas, Huw J W; Tomlinson, Ian P M

    2003-02-27

    Germ-line mutations in the base-excision-repair gene MYH have been associated with recessive inheritance of multiple colorectal adenomas. Tumors from affected persons displayed excess somatic transversions of a guanine-cytosine pair to a thymine-adenine pair (G:C-->T:A) in the APC gene. We screened for germ-line MYH mutations in 152 patients with multiple (3 to 100) colorectal adenomas and 107 APC-mutation-negative probands with classic familial adenomatous polyposis (>100 adenomas). Subgroups were analyzed for changes in the related genes MTH1 and OGG1. Adenomas were tested for somatic APC mutations. Six patients with multiple adenomas and eight patients with polyposis had biallelic germline MYH variants. Missense and protein-truncating mutations were found, and the spectrums of mutations were very similar in the two groups of patients. In the tumors of carriers of biallelic mutations, all somatic APC mutations were G:C-->T:A transversions. In the group with multiple adenomas, about one third of patients with more than 15 adenomas had biallelic MYH mutations. In the polyposis group, no patient with biallelic MYH mutations had severe disease (>1000 adenomas), but three had extracolonic disease. No clearly pathogenic MTH1 or OGG1 mutations were identified. Germ-line MYH mutations predispose persons to a recessive phenotype, multiple adenomas, or polyposis coli. For patients with about 15 or more colorectal adenomas--especially if no germ-line APC mutation has been identified and the family history is compatible with recessive inheritance--genetic testing of MYH is indicated for diagnosis and calculation of the level of risk in relatives. Clinical care of patients with biallelic MYH mutations should be similar to that of patients with classic or attenuated familial adenomatous polyposis. Copyright 2003 Massachusetts Medical Society

  3. Discrimination of germline V genes at different sequencing lengths and mutational burdens: A new tool for identifying and evaluating the reliability of V gene assignment.

    PubMed

    Zhang, Bochao; Meng, Wenzhao; Prak, Eline T Luning; Hershberg, Uri

    2015-12-01

    Immune repertoires are collections of lymphocytes that express diverse antigen receptor gene rearrangements consisting of Variable (V), (Diversity (D) in the case of heavy chains) and Joining (J) gene segments. Clonally related cells typically share the same germline gene segments and have highly similar junctional sequences within their third complementarity determining regions. Identifying clonal relatedness of sequences is a key step in the analysis of immune repertoires. The V gene is the most important for clone identification because it has the longest sequence and the greatest number of sequence variants. However, accurate identification of a clone's germline V gene source is challenging because there is a high degree of similarity between different germline V genes. This difficulty is compounded in antibodies, which can undergo somatic hypermutation. Furthermore, high-throughput sequencing experiments often generate partial sequences and have significant error rates. To address these issues, we describe a novel method to estimate which germline V genes (or alleles) cannot be discriminated under different conditions (read lengths, sequencing errors or somatic hypermutation frequencies). Starting with any set of germline V genes, this method measures their similarity using different sequencing lengths and calculates their likelihood of unambiguous assignment under different levels of mutation. Hence, one can identify, under different experimental and biological conditions, the germline V genes (or alleles) that cannot be uniquely identified and bundle them together into groups of specific V genes with highly similar sequences.

  4. A novel APC promoter 1B deletion shows a founder effect in Italian patients with classical familial adenomatous polyposis phenotype.

    PubMed

    Marabelli, Monica; Gismondi, Viviana; Ricci, Maria Teresa; Vetro, Annalisa; Abou Khouzam, Raefa; Rea, Valentina; Vitellaro, Marco; Zuffardi, Orsetta; Varesco, Liliana; Ranzani, Guglielmina Nadia

    2017-08-09

    Familial adenomatous polyposis is a Mendelian syndrome in which germline loss-of-function mutations of APC are associated with multiple adenomatous polyps of the large bowel, a multiplicity of extracolonic features, and a high lifetime risk of colorectal cancer. Different APC germline mutations have been identified, including sequence changes, genomic rearrangements, and expression defects. Recently, very rare families have been associated with constitutive large deletions encompassing the APC-5' regulatory region, while leaving the remaining gene sequence intact; the regulatory region contains a proximal and a distal promoter, called 1A and 1B, respectively. We identified a novel deletion encompassing promoter 1B in a large Italian family that manifested polyposis in three of the six branches descending from a founding couple married in 1797. By combining different molecular approaches on both DNA and RNA, we precisely mapped this deletion (6858 bp in length) that proved to be associated with APC allele silencing. The finding of the same deletion in two additional polyposis families pointed to a founder mutation in Italy. Deletion carriers from the three families all showed a "classical" polyposis phenotype. To explore the molecular mechanisms underlying promoter deletions, we performed an in silico analysis of the breakpoints of 1A and 1B rearrangements so far reported in the literature; moreover, to decipher genotype-phenotype correlations, we critically reviewed current knowledge on deletions versus point mutations in the APC-5' regulatory region. © 2017 Wiley Periodicals, Inc.

  5. Whole-genome sequencing in autism identifies hot spots for de novo germline mutation.

    PubMed

    Michaelson, Jacob J; Shi, Yujian; Gujral, Madhusudan; Zheng, Hancheng; Malhotra, Dheeraj; Jin, Xin; Jian, Minghan; Liu, Guangming; Greer, Douglas; Bhandari, Abhishek; Wu, Wenting; Corominas, Roser; Peoples, Aine; Koren, Amnon; Gore, Athurva; Kang, Shuli; Lin, Guan Ning; Estabillo, Jasper; Gadomski, Therese; Singh, Balvindar; Zhang, Kun; Akshoomoff, Natacha; Corsello, Christina; McCarroll, Steven; Iakoucheva, Lilia M; Li, Yingrui; Wang, Jun; Sebat, Jonathan

    2012-12-21

    De novo mutation plays an important role in autism spectrum disorders (ASDs). Notably, pathogenic copy number variants (CNVs) are characterized by high mutation rates. We hypothesize that hypermutability is a property of ASD genes and may also include nucleotide-substitution hot spots. We investigated global patterns of germline mutation by whole-genome sequencing of monozygotic twins concordant for ASD and their parents. Mutation rates varied widely throughout the genome (by 100-fold) and could be explained by intrinsic characteristics of DNA sequence and chromatin structure. Dense clusters of mutations within individual genomes were attributable to compound mutation or gene conversion. Hypermutability was a characteristic of genes involved in ASD and other diseases. In addition, genes impacted by mutations in this study were associated with ASD in independent exome-sequencing data sets. Our findings suggest that regional hypermutation is a significant factor shaping patterns of genetic variation and disease risk in humans.

  6. Polymorphisms in the adenomatous polyposis coli (APC) gene and advanced colorectal adenoma risk.

    PubMed

    Wong, Hui-Lee; Peters, Ulrike; Hayes, Richard B; Huang, Wen-Yi; Schatzkin, Arthur; Bresalier, Robert S; Velie, Ellen M; Brody, Lawrence C

    2010-09-01

    While germline mutations in the adenomatous polyposis coli (APC) gene cause the hereditary colon cancer syndrome (familial adenomatous polyposis (FAP)), the role of common germline APC variants in sporadic adenomatous polyposis remains unclear. We studied the association of eight APC single nucleotide polymorphisms (SNPs), possibly associated with functional consequences, and previously identified gene-environment (dietary fat intake and hormone replacement therapy (HRT) use) interactions, in relation to advanced colorectal adenoma in 758 cases and 767 sex- and race-matched controls, randomly selected from the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Cases had at least one verified advanced adenoma of the distal colon; controls, a negative sigmoidoscopy. We did not observe an association between genotypes for any of the eight APC SNPs and advanced distal adenoma risk (P(global gene-based)=0.92). Frequencies of identified common haplotypes did not differ between cases and controls (P(global haplotype test)=0.97). However, the risk for advanced distal adenoma was threefold higher for one rare haplotype (cases: 2.7%; controls: 1.6%) (odds ratio (OR)=3.27; 95% confidence interval (CI)=1.08-9.88). The genetic association between D1822V and advanced distal adenoma was confined to persons consuming a high-fat diet (P(interaction)=0.03). Similar interactions were not observed with HRT use. In our large, nested case-control study of advanced distal adenoma and clinically verified adenoma-free controls, we observed no association between specific APC SNPs and advanced adenoma. Fat intake modified the APC D1822V-adenoma association, but further studies are warranted.

  7. Contribution of APC and MUTYH mutations to familial adenomatous polyposis susceptibility in Hungary.

    PubMed

    Papp, Janos; Kovacs, Marietta Eva; Matrai, Zoltan; Orosz, Enikő; Kásler, Miklós; Børresen-Dale, Anne-Lise; Olah, Edith

    2016-01-01

    Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome with considerable genetic and phenotypic heterogeneity, defined by the development of multiple adenomas throughout the colorectum. FAP is caused either by monoallelic mutations in the adenomatous polyposis coli gene APC, or by biallelic germline mutations of MUTYH, this latter usually presenting with milder phenotype. The aim of the present study was to characterize the genotype and phenotype of Hungarian FAP patients. Mutation screening of 87 unrelated probands from FAP families (21 of them presented as the attenuated variant of the disease, showing <100 polyps) was performed using DNA sequencing and multiplex ligation-dependent probe amplification. Twenty-four different pathogenic mutations in APC were identified in 65 patients (75 %), including nine cases (37.5 %) with large genomic alterations. Twelve of the point mutations were novel. In addition, APC-negative samples were also tested for MUTYH mutations and we were able to identify biallelic pathogenic mutations in 23 % of these cases (5/22). Correlations between the localization of APC mutations and the clinical manifestations of the disease were observed, cases with a mutation in the codon 1200-1400 region showing earlier age of disease onset (p < 0.003). There were only a few, but definitive dissimilarities between APC- and MUTYH-associated FAP in our cohort: the age at onset of polyposis was significantly delayed for biallelic MUTYH mutation carriers as compared to patients with an APC mutation. Our data represent the first comprehensive study delineating the mutation spectra of both APC and MUTYH in Hungarian FAP families, and underscore the overlap between the clinical characteristics of APC- and MUTYH-associated phenotypes, necessitating a more appropriate clinical characterization of FAP families.

  8. Whole-animal genome-wide RNAi screen identifies networks regulating male germline stem cells in Drosophila

    PubMed Central

    Liu, Ying; Ge, Qinglan; Chan, Brian; Liu, Hanhan; Singh, Shree Ram; Manley, Jacob; Lee, Jae; Weideman, Ann Marie; Hou, Gerald; Hou, Steven X.

    2016-01-01

    Stem cells are regulated both intrinsically and externally, including by signals from the local environment and distant organs. To identify genes and pathways that regulate stem-cell fates in the whole organism, we perform a genome-wide transgenic RNAi screen through ubiquitous gene knockdowns, focusing on regulators of adult Drosophila testis germline stem cells (GSCs). Here we identify 530 genes that regulate GSC maintenance and differentiation. Of these, we further knock down 113 selected genes using cell-type-specific Gal4s and find that more than half were external regulators, that is, from the local microenvironment or more distal sources. Some genes, for example, versatile (vers), encoding a heterochromatin protein, regulates GSC fates differentially in different cell types and through multiple pathways. We also find that mitosis/cytokinesis proteins are especially important for male GSC maintenance. Our findings provide valuable insights and resources for studying stem cell regulation at the organismal level. PMID:27484291

  9. Whole-exome identifies RXRG and TH germline variants in familial isolated prolactinoma.

    PubMed

    Melo, Flavia M; Couto, Patrícia P; Bale, Allen E; Bastos-Rodrigues, Luciana; Passos, Flavia M; Lisboa, Raony G C; Ng, Jessica M Y; Curran, Tom; Dias, Eduardo P; Friedman, Eitan; De Marco, Luiz

    2016-06-01

    Familial isolated pituitary adenoma (FIPA) is a rare genetic disorder. In a subset of FIPA families AIP germline mutations have been reported, but in most FIPA cases the exact genetic defect remains unknown. The present study aimed to determine the genetic basis of FIPA in a Brazilian family. Three siblings presented with isolated prolactin genes. Further mutation screening was performed using whole-exome sequencing and all likely causative mutations were validated by Sanger sequencing. In silico analysis and secreting pituitary adenoma diagnosed through clinical, biochemical and imaging testing. Sanger sequencing was used to genotype candidate prolactinoma-mutated additional predictive algorithms were applied to prioritize likely pathogenic variants. No mutations in the coding and flanking intronic regions in the MEN1, AIP and PRLR genes were detected. Whole-exome sequencing of three affected siblings revealed novel, predicted damaging, heterozygous variants in three different genes: RXRG, REXO4 and TH. In conclusion, the RXRG and TH possibly pathogenic variants may be associated with isolated prolactinoma in the studied family. The possible contribution of these genes to additional FIPA families should be explored.

  10. Distinct deregulation of the hypoxia inducible factor by PHD2 mutants identified in germline DNA of patients with polycythemia

    PubMed Central

    Ladroue, Charline; Hoogewijs, David; Gad, Sophie; Carcenac, Romain; Storti, Federica; Barrois, Michel; Gimenez-Roqueplo, Anne-Paule; Leporrier, Michel; Casadevall, Nicole; Hermine, Olivier; Kiladjian, Jean-Jacques; Baruchel, André; Fakhoury, Fadi; Bressac-de Paillerets, Brigitte; Feunteun, Jean; Mazure, Nathalie; Pouysségur, Jacques; Wenger, Roland H.; Richard, Stéphane; Gardie, Betty

    2012-01-01

    Background Congenital secondary erythrocytoses are due to deregulation of hypoxia inducible factor resulting in overproduction of erythropoietin. The most common germline mutation identified in the hypoxia signaling pathway is the Arginine 200-Tryptophan mutant of the von Hippel-Lindau tumor suppressor gene, resulting in Chuvash polycythemia. This mutant displays a weak deficiency in hypoxia inducible factor α regulation and does not promote tumorigenesis. Other von Hippel-Lindau mutants with more deleterious effects are responsible for von Hippel-Lindau disease, which is characterized by the development of multiple tumors. Recently, a few mutations in gene for the prolyl hydroxylase domain 2 protein (PHD2) have been reported in cases of congenital erythrocytosis not associated with tumor formation with the exception of one patient with a recurrent extra-adrenal paraganglioma. Design and Methods Five PHD2 variants, four of which were novel, were identified in patients with erythrocytosis. These PHD2 variants were functionally analyzed and compared with the PHD2 mutant previously identified in a patient with polycythemia and paraganglioma. The capacity of PHD2 to regulate the activity, stability and hydroxylation of hypoxia inducible factor α was assessed using hypoxia-inducible reporter gene, one-hybrid and in vitro hydroxylation assays, respectively. Results This functional comparative study showed that two categories of PHD2 mutants could be distinguished: one category with a weak deficiency in hypoxia inducible factor α regulation and a second one with a deleterious effect; the mutant implicated in tumor occurrence belongs to the second category. Conclusions As observed with germline von Hippel-Lindau mutations, there are functional differences between the PHD2 mutants with regards to hypoxia inducible factor regulation. PHD2 mutation carriers do, therefore, need careful medical follow-up, since some mutations must be considered as potential candidates for

  11. Germline MLH1 Mutations Are Frequently Identified in Lynch Syndrome Patients With Colorectal and Endometrial Carcinoma Demonstrating Isolated Loss of PMS2 Immunohistochemical Expression.

    PubMed

    Dudley, Beth; Brand, Randall E; Thull, Darcy; Bahary, Nathan; Nikiforova, Marina N; Pai, Reetesh K

    2015-08-01

    Current guidelines on germline mutation testing for patients suspected of having Lynch syndrome are not entirely clear in patients with tumors demonstrating isolated loss of PMS2 immunohistochemical expression. We analyzed the clinical and pathologic features of patients with tumors demonstrating isolated loss of PMS2 expression in an attempt to (1) determine the frequency of germline MLH1 and PMS2 mutations and (2) correlate mismatch-repair protein immunohistochemistry and tumor histology with germline mutation results. A total of 3213 consecutive colorectal carcinomas and 215 consecutive endometrial carcinomas were prospectively analyzed for DNA mismatch-repair protein expression by immunohistochemistry. In total, 32 tumors from 31 patients demonstrated isolated loss of PMS2 immunohistochemical expression, including 16 colorectal carcinomas and 16 endometrial carcinomas. Microsatellite instability (MSI) polymerase chain reaction was performed in 29 tumors from 28 patients with the following results: 28 tumors demonstrated high-level MSI, and 1 tumor demonstrated low-level MSI. Twenty of 31 (65%) patients in the study group had tumors demonstrating histopathology associated with high-level MSI. Seventeen patients underwent germline mutation analysis with the following results: 24% with MLH1 mutations, 35% with PMS2 mutations, 12% with PMS2 variants of undetermined significance, and 29% with no mutations in either MLH1 or PMS2. Three of the 4 patients with MLH1 germline mutations had a mutation that results in decreased stability and quantity of the MLH1 protein that compromises the MLH1-PMS2 protein complex, helping to explain the presence of immunogenic but functionally inactive MLH1 protein within the tumor. The high frequency of MLH1 germline mutations identified in our study has important implications for testing strategies in patients suspected of having Lynch syndrome and indicates that patients with tumors demonstrating isolated loss of PMS2 expression

  12. Inactivation of promoter 1B of APC causes partial gene silencing: evidence for a significant role of the promoter in regulation and causative of familial adenomatous polyposis

    PubMed Central

    Rohlin, A; Engwall, Y; Fritzell, K; Göransson, K; Bergsten, A; Einbeigi, Z; Nilbert, M; Karlsson, P; Björk, J; Nordling, M

    2011-01-01

    Familial adenomatous polyposis (FAP) is caused by germline mutations in the adenomatous polyposis coli (APC) gene. Two promoters, 1A and 1B, have been recognized in APC, and 1B is thought to have a minor role in the regulation of the gene. We have identified a novel deletion encompassing half of this promoter in the largest family (Family 1) of the Swedish Polyposis Registry. The mutation leads to an imbalance in allele-specific expression of APC, and transcription from promoter 1B was highly impaired in both normal colorectal mucosa and blood from mutation carriers. To establish the significance of promoter 1B in normal colorectal mucosa (from controls), expression levels of specific transcripts from each of the promoters, 1A and 1B, were examined, and the expression from 1B was significantly higher compared with 1A. Significant amounts of transcripts generated from promoter 1B were also determined in a panel of 20 various normal tissues examined. In FAP-related tumors, the APC germline mutation is proposed to dictate the second hit. Mutations leaving two or three out of seven 20-amino-acid repeats in the central domain of APC intact seem to be required for tumorigenesis. We examined adenomas from mutation carriers in Family 1 for second hits in the entire gene without any findings, however, loss of the residual expression of the deleterious allele was observed. Three major conclusions of significant importance in relation to the function of APC can be drawn from this study; (i) germline inactivation of promoter 1B is disease causing in FAP; (ii) expression of transcripts from promoter 1B is generated at considerable higher levels compared with 1A, demonstrating a hitherto unknown importance of 1B; (iii) adenoma formation in FAP, caused by impaired function of promoter 1B, does not require homozygous inactivation of APC allowing for alternative genetic models as basis for adenoma formation. PMID:21643010

  13. Colorectal cancer risk variants at 8q23.3 and 11q23.1 are associated with disease phenotype in APC mutation carriers.

    PubMed

    Ghorbanoghli, Z; Nieuwenhuis, M H; Houwing-Duistermaat, J J; Jagmohan-Changur, S; Hes, F J; Tops, C M; Wagner, A; Aalfs, C M; Verhoef, S; Gómez García, E B; Sijmons, R H; Menko, F H; Letteboer, T G; Hoogerbrugge, N; van Wezel, T; Vasen, H F A; Wijnen, J T

    2016-10-01

    Familial adenomatous polyposis (FAP) is a dominantly inherited syndrome caused by germline mutations in the APC gene and characterized by the development of multiple colorectal adenomas and a high risk of developing colorectal cancer (CRC). The severity of polyposis is correlated with the site of the APC mutation. However, there is also phenotypic variability within families with the same underlying APC mutation, suggesting that additional factors influence the severity of polyposis. Genome-wide association studies identified several single nucleotide polymorphisms (SNPs) that are associated with CRC. We assessed whether these SNPs are associated with polyp multiplicity in proven APC mutation carriers. Sixteen CRC-associated SNPs were analysed in a cohort of 419 APC germline mutation carriers from 182 families. Clinical data were retrieved from the Dutch Polyposis Registry. Allele frequencies of the SNPs were compared for patients with <100 colorectal adenomas versus patients with ≥100 adenomas, using generalized estimating equations with the APC genotype as a covariate. We found a trend of association of two of the tested SNPs with the ≥100 adenoma phenotype: the C alleles of rs16892766 at 8q23.3 (OR 1.71, 95 % CI 1.05-2.76, p = 0.03, dominant model) and rs3802842 at 11q23.1 (OR 1.51, 95 % CI 1.03-2.22, p = 0.04, dominant model). We identified two risk variants that are associated with a more severe phenotype in APC mutation carriers. These risk variants may partly explain the phenotypic variability in families with the same APC gene defect. Further studies with a larger sample size are recommended to evaluate and confirm the phenotypic effect of these SNPs in FAP.

  14. Genome-Wide Association Study of Golden Retrievers Identifies Germ-Line Risk Factors Predisposing to Mast Cell Tumours

    PubMed Central

    Arendt, Maja L.; Melin, Malin; Tonomura, Noriko; Koltookian, Michele; Courtay-Cahen, Celine; Flindall, Netty; Bass, Joyce; Boerkamp, Kim; Megquir, Katherine; Youell, Lisa; Murphy, Sue; McCarthy, Colleen; London, Cheryl; Rutteman, Gerard R.; Starkey, Mike; Lindblad-Toh, Kerstin

    2015-01-01

    Canine mast cell tumours (CMCT) are one of the most common skin tumours in dogs with a major impact on canine health. Certain breeds have a higher risk of developing mast cell tumours, suggesting that underlying predisposing germ-line genetic factors play a role in the development of this disease. The genetic risk factors are largely unknown, although somatic mutations in the oncogene C-KIT have been detected in a proportion of CMCT, making CMCT a comparative model for mastocytosis in humans where C-KIT mutations are frequent. We have performed a genome wide association study in golden retrievers from two continents and identified separate regions in the genome associated with risk of CMCT in the two populations. Sequence capture of associated regions and subsequent fine mapping in a larger cohort of dogs identified a SNP associated with development of CMCT in the GNAI2 gene (p = 2.2x10-16), introducing an alternative splice form of this gene resulting in a truncated protein. In addition, disease associated haplotypes harbouring the hyaluronidase genes HYAL1, HYAL2 and HYAL3 on cfa20 and HYAL4, SPAM1 and HYALP1 on cfa14 were identified as separate risk factors in European and US golden retrievers, respectively, suggesting that turnover of hyaluronan plays an important role in the development of CMCT. PMID:26588071

  15. Mapping Complex Traits in a Diversity Outbred F1 Mouse Population Identifies Germline Modifiers of Metastasis in Human Prostate Cancer.

    PubMed

    Winter, Jean M; Gildea, Derek E; Andreas, Jonathan P; Gatti, Daniel M; Williams, Kendra A; Lee, Minnkyong; Hu, Ying; Zhang, Suiyuan; Mullikin, James C; Wolfsberg, Tyra G; McDonnell, Shannon K; Fogarty, Zachary C; Larson, Melissa C; French, Amy J; Schaid, Daniel J; Thibodeau, Stephen N; Churchill, Gary A; Crawford, Nigel P S

    2017-01-25

    It is unclear how standing genetic variation affects the prognosis of prostate cancer patients. To provide one controlled answer to this problem, we crossed a dominant, penetrant mouse model of prostate cancer to Diversity Outbred mice, a collection of animals that carries over 40 million SNPs. Integration of disease phenotype and SNP variation data in 493 F1 males identified a metastasis modifier locus on Chromosome 8 (LOD = 8.42); further analysis identified the genes Rwdd4, Cenpu, and Casp3 as functional effectors of this locus. Accordingly, analysis of over 5,300 prostate cancer patient samples revealed correlations between the presence of genetic variants at these loci, their expression levels, cancer aggressiveness, and patient survival. We also observed that ectopic overexpression of RWDD4 and CENPU increased the aggressiveness of two human prostate cancer cell lines. In aggregate, our approach demonstrates how well-characterized genetic variation in mice can be harnessed in conjunction with systems genetics approaches to identify and characterize germline modifiers of human disease processes.

  16. Low-level APC mutational mosaicism is the underlying cause in a substantial fraction of unexplained colorectal adenomatous polyposis cases.

    PubMed

    Spier, Isabel; Drichel, Dmitriy; Kerick, Martin; Kirfel, Jutta; Horpaopan, Sukanya; Laner, Andreas; Holzapfel, Stefanie; Peters, Sophia; Adam, Ronja; Zhao, Bixiao; Becker, Tim; Lifton, Richard P; Perner, Sven; Hoffmann, Per; Kristiansen, Glen; Timmermann, Bernd; Nöthen, Markus M; Holinski-Feder, Elke; Schweiger, Michal R; Aretz, Stefan

    2016-03-01

    In 30-50% of patients with colorectal adenomatous polyposis, no germline mutation in the known genes APC, causing familial adenomatous polyposis, MUTYH, causing MUTYH-associated polyposis, or POLE or POLD1, causing polymerase-proofreading-associated polyposis can be identified, although a hereditary aetiology is likely. This study aimed to explore the impact of APC mutational mosaicism in unexplained polyposis. To comprehensively screen for somatic low-level APC mosaicism, high-coverage next-generation sequencing of the APC gene was performed using DNA from leucocytes and a total of 53 colorectal tumours from 20 unrelated patients with unexplained sporadic adenomatous polyposis. APC mosaicism was assumed if the same loss-of-function APC mutation was present in ≥ 2 anatomically separated colorectal adenomas/carcinomas per patient. All mutations were validated using diverse methods. In 25% (5/20) of patients, somatic mosaicism of a pathogenic APC mutation was identified as underlying cause of the disease. In 2/5 cases, the mosaic level in leucocyte DNA was slightly below the sensitivity threshold of Sanger sequencing; while in 3/5 cases, the allelic fraction was either very low (0.1-1%) or no mutations were detectable. The majority of mosaic mutations were located outside the somatic mutation cluster region of the gene. The present data indicate a high prevalence of pathogenic mosaic APC mutations below the detection thresholds of routine diagnostics in adenomatous polyposis, even if high-coverage sequencing of leucocyte DNA alone is taken into account. This has important implications for both routine work-up and strategies to identify new causative genes in this patient group. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  17. Identification of an APC Variant in a Patient with Clinical Attenuated Familial Adenomatous Polyposis.

    PubMed

    Schlussel, Andrew T; Donlon, Susan S; Eggerding, Faye A; Gagliano, Ronald A

    2014-01-01

    Introduction. The objective of this case report is to discuss an unclassified germline variant of the adenomatous polyposis coli (APC) gene identified in an older patient with attenuated familial adenomatous polyposis syndrome (AFAP). Methods. We present a case report of a 66-year-old man diagnosed with AFAP. Colonoscopy found multiple polyps and invasive adenocarcinoma arising in the transverse colon. Samples were tested for mutations in the APC gene. Results. DNA sequencing of germline DNA identified a cytosine (C) to thymine (T) transition at nucleotide 1240, heterozygous. The C to T transition at codon 414 is predicted to convert an arginine residue to a cysteine that is possibly pathogenic. Analysis of the patient's colon tumor DNA indicated that the tumor had lost the mutant variant allele and retained only the normal allele, suggesting that the variant may not be significant. Conclusions. The p.R414C variant has been described previously as a germline mutation of probable pathogenicity. This substitution should be considered an unclassified variant and possibly not pathogenic. These findings support the need for further genetic testing of tissue, as well as for developing a mechanism for testing all variants, as this could significantly impact the lives of patients and their family members.

  18. Ectopic Activation of Germline and Placental Genes Identifies Aggressive Metastasis-Prone Lung Cancers

    PubMed Central

    Rousseaux, Sophie; Debernardi, Alexandra; Jacquiau, Baptiste; Vitte, Anne-Laure; Vesin, Aurélien; Nagy-Mignotte, Hélène; Moro-Sibilot, Denis; Brichon, Pierre-Yves; Lantuejoul, Sylvie; Hainaut, Pierre; Laffaire, Julien; de Reyniès, Aurélien; Beer, David G.; Timsit, Jean-François; Brambilla, Christian; Brambilla, Elisabeth; Khochbin, Saadi

    2016-01-01

    Activation of normally silent tissue-specific genes and the resulting cell “identity crisis” are the unexplored consequences of malignant epigenetic reprogramming. We designed a strategy for investigating this reprogramming, which consisted of identifying a large number of tissue-restricted genes that are epigenetically silenced in normal somatic cells and then detecting their expression in cancer. This approach led to the demonstration that large-scale “off-context” gene activations systematically occur in a variety of cancer types. In our series of 293 lung tumors, we identified an ectopic gene expression signature associated with a subset of highly aggressive tumors, which predicted poor prognosis independently of the TNM (tumor size, node positivity, and metastasis) stage or histological subtype. The ability to isolate these tumors allowed us to reveal their common molecular features characterized by the acquisition of embryonic stem cell/germ cell gene expression profiles and the down-regulation of immune response genes. The methodical recognition of ectopic gene activations in cancer cells could serve as a basis for gene signature–guided tumor stratification, as well as for the discovery of oncogenic mechanisms, and expand the understanding of the biology of very aggressive tumors. PMID:23698379

  19. Genome-Wide Analysis Identifies Germ-Line Risk Factors Associated with Canine Mammary Tumours

    PubMed Central

    Melin, Malin; Murén, Eva; Gustafson, Ulla; Starkey, Mike; Borge, Kaja Sverdrup; Lingaas, Frode; Saellström, Sara; Rönnberg, Henrik; Lindblad-Toh, Kerstin

    2016-01-01

    Canine mammary tumours (CMT) are the most common neoplasia in unspayed female dogs. CMTs are suitable naturally occurring models for human breast cancer and share many characteristics, indicating that the genetic causes could also be shared. We have performed a genome-wide association study (GWAS) in English Springer Spaniel dogs and identified a genome-wide significant locus on chromosome 11 (praw = 5.6x10-7, pperm = 0.019). The most associated haplotype spans a 446 kb region overlapping the CDK5RAP2 gene. The CDK5RAP2 protein has a function in cell cycle regulation and could potentially have an impact on response to chemotherapy treatment. Two additional loci, both on chromosome 27, were nominally associated (praw = 1.97x10-5 and praw = 8.30x10-6). The three loci explain 28.1±10.0% of the phenotypic variation seen in the cohort, whereas the top ten associated regions account for 38.2±10.8% of the risk. Furthermore, the ten GWAS loci and regions with reduced genetic variability are significantly enriched for snoRNAs and tumour-associated antigen genes, suggesting a role for these genes in CMT development. We have identified several candidate genes associated with canine mammary tumours, including CDK5RAP2. Our findings enable further comparative studies to investigate the genes and pathways in human breast cancer patients. PMID:27158822

  20. Novel strategies for comprehensive mutation screening of the APC gene.

    PubMed

    Wachsmannova, L; Mego, M; Stevurkova, V; Zajac, V; Ciernikova, S

    2017-03-03

    Colorectal cancer is the 4th most common cause of cancer related deaths worldwide and new possibilities in accurate diagnosis and targeted treatment are highly required. Mutations in adenomatous polyposis coli (APC) gene play a pivotal role in adenoma-carcinoma pathway of colorectal tumorigenesis. The quarter century from its´ first cloning, APC became one of the most frequently mutated, known driver genes in colorectal cancer. Intensive routine molecular testing of APC has brought the benefits for patients with family history of polyposis or colorectal cancer. Nevertheless, multiple mutational disease-causing mechanisms make the genetic testing still challenging. This minireview is focused on implementation of novel APC mutation screening diagnostic strategies for polyposis families according to the current findings. A further understanding and improved algorithms may help to increase the mutation detection rate. APC germline mutations achieve close to 100% penetrance, so more comprehensive approach followed by preventive and therapeutic strategies might reflect in decrease in burden of colorectal cancer.

  1. Mechanism of APC/CCDC20 activation by mitotic phosphorylation

    PubMed Central

    Qiao, Renping; Weissmann, Florian; Yamaguchi, Masaya; Brown, Nicholas G.; VanderLinden, Ryan; Imre, Richard; Jarvis, Marc A.; Brunner, Michael R.; Davidson, Iain F.; Litos, Gabriele; Haselbach, David; Mechtler, Karl; Stark, Holger; Schulman, Brenda A.; Peters, Jan-Michael

    2016-01-01

    Chromosome segregation and mitotic exit are initiated by the 1.2-MDa ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) and its coactivator CDC20 (cell division cycle 20). To avoid chromosome missegregation, APC/CCDC20 activation is tightly controlled. CDC20 only associates with APC/C in mitosis when APC/C has become phosphorylated and is further inhibited by a mitotic checkpoint complex until all chromosomes are bioriented on the spindle. APC/C contains 14 different types of subunits, most of which are phosphorylated in mitosis on multiple sites. However, it is unknown which of these phospho-sites enable APC/CCDC20 activation and by which mechanism. Here we have identified 68 evolutionarily conserved mitotic phospho-sites on human APC/C bound to CDC20 and have used the biGBac technique to generate 47 APC/C mutants in which either all 68 sites or subsets of them were replaced by nonphosphorylatable or phospho-mimicking residues. The characterization of these complexes in substrate ubiquitination and degradation assays indicates that phosphorylation of an N-terminal loop region in APC1 is sufficient for binding and activation of APC/C by CDC20. Deletion of the N-terminal APC1 loop enables APC/CCDC20 activation in the absence of mitotic phosphorylation or phospho-mimicking mutations. These results indicate that binding of CDC20 to APC/C is normally prevented by an autoinhibitory loop in APC1 and that its mitotic phosphorylation relieves this inhibition. The predicted location of the N-terminal APC1 loop implies that this loop controls interactions between the N-terminal domain of CDC20 and APC1 and APC8. These results reveal how APC/C phosphorylation enables CDC20 to bind and activate the APC/C in mitosis. PMID:27114510

  2. Identification of APC gene mutations in jejunal carcinomas from a patient with familial adenomatous polyposis.

    PubMed

    Ishida, Hideyuki; Kumamoto, Kensuke; Amano, Kunihiko; Ishibashi, Keiichiro; Iwama, Takeo; Higashi, Morihiro; Tamaru, Junichi

    2013-09-01

    Jejunal carcinoma in patients with familial adenomatous polyposis has been rarely reported, and little is known about its association with genetic alterations of the APC gene. A 52-year-old woman with familial adenomatous polyposis underwent palliative resection of the proximal jejunum because of two circumferential tumors associated with peritoneal carcinomatosis. A histological examination revealed that one tumor was a poorly differentiated adenocarcinoma, and that the other was a moderately differentiated adenocarcinoma with adenomatous components. The patient did not respond to standard chemotherapy and died of disseminated disease 8 months after surgery. A genetic analysis of the APC gene identified somatic mutations in each tumor (c.4450delAG and p.R1450X) in addition to the germline mutation (c.3984del5), all of which form stop codons, resulting in truncated APC products. This report is the first description of how a second hit to the APC gene can be involved in carcinogenesis of the jejunum in familial adenomatous polyposis.

  3. DNA Methylation Identifies Loci Distinguishing Hereditary Nonpolyposis Colorectal Cancer Without Germ-Line MLH1/MSH2 Mutation from Sporadic Colorectal Cancer

    PubMed Central

    Chen, Chung-Hsing; Sheng Jiang, Shih; Hsieh, Ling-Ling; Tang, Reiping; Hsiung, Chao A; Tsai, Hui-Ju; Chang, I-Shou

    2016-01-01

    Objectives: Roughly half of hereditary nonpolyposis colorectal cancer (HNPCC) cases are Lynch syndrome and exhibit germ-line mutations in DNA mismatch repair (MMR) genes; the other half are familial colorectal cancer (CRC) type X (FCCTX) and are MMR proficient. About 70% of Lynch syndrome tumors have germ-line MLH1 or MSH2 mutations. The clinical presentation, histopathological features, and carcinogenesis of FCCTX resemble those of sporadic MMR-proficient colorectal tumors. It is of interest to obtain biomarkers that distinguish FCCTX from sporadic microsatellite stable (MSS) CRC, to develop preventive strategies. Methods: The tumors and adjacent normal tissues of 40 patients with HNPCC were assayed using the Illumina Infinium HumanMethylation27 (HM27) BeadChip to assess the DNA methylation level at about 27,000 loci. The germ-line mutation status of MLH1 and MSH2 and the microsatellite instability status in these patients were obtained. Genome-wide DNA methylation measurements of three groups of patients with general CRC were downloaded from public domain databases. Probes with DNA methylation levels that differed significantly between patients with sporadic MSS CRC and FCCTX were examined, to explore their potential as biomarkers. Results: We found that MSS HNPCC tumors were overwhelmingly hypomethylated compared with those from patient groups with other types of CRC, including germ-line MLH1/MSH2-mutated HNPCC and sporadic MSS CRC. Five gene-marker panels that exhibited a sensitivity of 100% and a specificity higher than 90% in both discovery and validation cohorts were proposed to distinguish MSS HNPCC tumors from sporadic MSS CRC. Conclusions: Our results warrant further investigation and validation. The loci identified here may become useful biomarkers for distinguishing between FCCTX and sporadic MSS CRC tumors. PMID:27977020

  4. Ab-origin: an enhanced tool to identify the sourcing gene segments in germline for rearranged antibodies

    PubMed Central

    Wang, Xiaojing; Wu, Di; Zheng, Siyuan; Sun, Jing; Tao, Lin; Li, Yixue; Cao, Zhiwei

    2008-01-01

    Background In the adaptive immune system, variable regions of immunoglobulin (IG) are encoded by random recombination of variable (V), diversity (D), and joining (J) gene segments in the germline. Partitioning the functional antibody sequences to their sourcing germline gene segments is vital not only for understanding antibody maturation but also for promoting the potential engineering of the therapeutic antibodies. To date, several tools have been developed to perform such "trace-back" calculations. Yet, the predicting ability and processing volume of those tools vary significantly for different sets of data. Moreover, none of them give a confidence for immunoglobulin heavy diversity (IGHD) identification. Developing fast, efficient and enhanced tools is always needed with the booming of immunological data. Results Here, a program named Ab-origin is presented. It is designed by batch query against germline databases based on empirical knowledge, optimized scoring scheme and appropriate parameters. Special efforts have been paid to improve the identification accuracy of the short and volatile region, IGHD. In particular, a threshold score for certain sensitivity and specificity is provided to give the confidence level of the IGHD identification. Conclusion When evaluated using different sets of both simulated data and experimental data, Ab-origin outperformed all the other five popular tools in terms of prediction accuracy. The features of batch query and confidence indication of IGHD identification would provide extra help to users. The program is freely available at . PMID:19091020

  5. Ab-origin: an enhanced tool to identify the sourcing gene segments in germline for rearranged antibodies.

    PubMed

    Wang, Xiaojing; Wu, Di; Zheng, Siyuan; Sun, Jing; Tao, Lin; Li, Yixue; Cao, Zhiwei

    2008-12-12

    In the adaptive immune system, variable regions of immunoglobulin (IG) are encoded by random recombination of variable (V), diversity (D), and joining (J) gene segments in the germline. Partitioning the functional antibody sequences to their sourcing germline gene segments is vital not only for understanding antibody maturation but also for promoting the potential engineering of the therapeutic antibodies. To date, several tools have been developed to perform such "trace-back" calculations. Yet, the predicting ability and processing volume of those tools vary significantly for different sets of data. Moreover, none of them give a confidence for immunoglobulin heavy diversity (IGHD) identification. Developing fast, efficient and enhanced tools is always needed with the booming of immunological data. Here, a program named Ab-origin is presented. It is designed by batch query against germline databases based on empirical knowledge, optimized scoring scheme and appropriate parameters. Special efforts have been paid to improve the identification accuracy of the short and volatile region, IGHD. In particular, a threshold score for certain sensitivity and specificity is provided to give the confidence level of the IGHD identification. When evaluated using different sets of both simulated data and experimental data, Ab-origin outperformed all the other five popular tools in terms of prediction accuracy. The features of batch query and confidence indication of IGHD identification would provide extra help to users. The program is freely available at http://mpsq.biosino.org/ab-origin/supplementary.html.

  6. Whole-gene APC deletions cause classical familial adenomatous polyposis, but not attenuated polyposis or “multiple” colorectal adenomas

    PubMed Central

    Sieber, O. M.; Lamlum, H.; Crabtree, M. D.; Rowan, A. J.; Barclay, E.; Lipton, L.; Hodgson, S.; Thomas, H. J. W.; Neale, K.; Phillips, R. K. S.; Farrington, S. M.; Dunlop, M. G.; Mueller, H. J.; Bisgaard, M. L.; Bulow, S.; Fidalgo, P.; Albuquerque, C.; Scarano, M. I.; Bodmer, W.; Tomlinson, I. P. M.; Heinimann, K.

    2002-01-01

    Familial adenomatous polyposis (FAP) is a dominantly inherited colorectal tumor predisposition that results from germ-line mutations in the APC gene (chromosome 5q21). FAP shows substantial phenotypic variability: classical polyposis patients develop more than 100 colorectal adenomas, whereas those with attenuated polyposis (AAPC) have fewer than 100 adenomas. A further group of individuals, so-called “multiple” adenoma patients, have a phenotype like AAPC, with 3–99 polyps throughout the colorectum, but mostly have no demonstrable germ-line APC mutation. Routine mutation detection techniques fail to detect a pathogenic APC germ-line mutation in approximately 30% of patients with classical polyposis and 90% of those with AAPC/multiple adenomas. We have developed a real-time quantitative multiplex PCR assay to detect APC exon 14 deletions. When this technique was applied to a set of 60 classical polyposis and 143 AAPC/multiple adenoma patients with no apparent APC germ-line mutation, deletions were found exclusively in individuals with classical polyposis (7 of 60, 12%). Fine-mapping of the region suggested that the majority (6 of 7) of these deletions encompassed the entire APC locus, confirming that haploinsufficiency can result in a classical polyposis phenotype. Screening for germ-line deletions in APC mutation-negative individuals with classical polyposis seems warranted. PMID:11867715

  7. Mutational spectrum of the APC and MUTYH genes and genotype–phenotype correlations in Brazilian FAP, AFAP, and MAP patients

    PubMed Central

    2013-01-01

    Background Patients with multiple colorectal adenomas are currently screened for germline mutations in two genes, APC and MUTYH. APC-mutated patients present classic or attenuated familial adenomatous polyposis (FAP/AFAP), while patients carrying biallelic MUTYH mutations exhibit MUTYH-associated polyposis (MAP). The spectrum of mutations as well as the genotype-phenotype correlations in polyposis syndromes present clinical impact and can be population specific, making important to obtain genetic and clinical data from different populations. Methods DNA sequencing of the complete coding region of the APC and MUTYH genes was performed in 23 unrelated Brazilian polyposis patients. In addition, mutation-negative patients were screened for large genomic rearrangements by multiplex ligation-dependent probe amplification, array-comparative genomic hybridization, and duplex quantitative PCR. Biallelic MUTYH mutations were confirmed by allele-specific PCR. Clinical data of the index cases and their affected relatives were used to assess genotype–phenotype correlations. Results Pathogenic mutations were identified in 20 of the 23 probands (87%): 14 in the APC gene and six in the MUTYH gene; six of them (30%) were described for the first time in this series. Genotype-phenotype correlations revealed divergent results compared with those described in other studies, particularly regarding the extent of polyposis and the occurrence of desmoid tumors in families with mutations before codon 1444 (6/8 families with desmoid). Conclusions This first comprehensive investigation of the APC and MUTYH mutation spectrum in Brazilian polyposis patients showed a high detection rate and identified novel pathogenic mutations. Notably, a significant number of APC-positive families were not consistent with the predicted genotype-phenotype correlations from other populations. PMID:23561487

  8. Genetic Mechanisms in Apc-Mediated Mammary Tumorigenesis

    PubMed Central

    Kuraguchi, Mari; Ohene-Baah, Nana Yaw; Sonkin, Dmitriy; Bronson, Roderick Terry; Kucherlapati, Raju

    2009-01-01

    Many components of Wnt/β-catenin signaling pathway also play critical roles in mammary tumor development, yet the role of the tumor suppressor gene APC (adenomatous polyposis coli) in breast oncongenesis is unclear. To better understand the role of Apc in mammary tumorigenesis, we introduced conditional Apc mutations specifically into two different mammary epithelial populations using K14-cre and WAP-cre transgenic mice that express Cre-recombinase in mammary progenitor cells and lactating luminal cells, respectively. Only the K14-cre–mediated Apc heterozygosity developed mammary adenocarcinomas demonstrating histological heterogeneity, suggesting the multilineage progenitor cell origin of these tumors. These tumors harbored truncation mutation in a defined region in the remaining wild-type allele of Apc that would retain some down-regulating activity of β-catenin signaling. Activating mutations at codons 12 and 61 of either H-Ras or K-Ras were also found in a subset of these tumors. Expression profiles of acinar-type mammary tumors from K14-cre; ApcCKO/+ mice showed luminal epithelial gene expression pattern, and clustering analysis demonstrated more correlation to MMTV-neu model than to MMTV-Wnt1. In contrast, neither WAP-cre–induced Apc heterozygous nor homozygous mutations resulted in predisposition to mammary tumorigenesis, although WAP-cre–mediated Apc deficiency resulted in severe squamous metaplasia of mammary glands. Collectively, our results suggest that not only the epithelial origin but also a certain Apc mutations are selected to achieve a specific level of β-catenin signaling optimal for mammary tumor development and explain partially the colon- but not mammary-specific tumor development in patients that carry germline mutations in APC. PMID:19197353

  9. A novel pathogenic large germline deletion in adenomatous polyposis coli gene in a Chinese family with familial adenomatous polyposis.

    PubMed

    Zhang, Zhao; Liang, Shengran; Huang, Hui; Wang, Dan; Zhang, Xipeng; Wu, Jing; Chen, Huishuang; Wang, Yanyan; Rong, Tingting; Zhou, Yulin; Banerjee, Santasree

    2016-08-02

    Germline mutations of the APC gene are associated with an autosomal dominant precancerous condition, termed familial adenomatous polyposis (FAP). FAP is clinically manifested by the presence of multiple colorectal adenomas or polyps. Gradually, these colorectal adenomas or polyps inevitably result in colorectal cancer by the third-to fourth decade of life. Surgical interventions or total proctocolectomy is the best possible treatment for FAP. Here, we present a clinical molecular study of a five generation Chinese family with FAP. Diagnosis of FAP was made on the basis of clinical manifestations, family history and medical (colonoscopy and histopathology) records. Blood samples were collected and genomic DNA was extracted. Genetic screening of the APC gene was performed by targeted next-generation sequencing and quantitative real-time PCR. Targeted next generation sequencing identified a novel heterozygous large deletion [exon5-exon16; c.423_8532del] of APC gene, which segregated with the FAP phenotypes in the proband and in all the affected family members. Unaffected family members and normal controls did not carry this deletion. In the Chinese population, most of the previously reported APC gene mutations are missense mutations. This is the first report describing the largest deletion of the APC gene in the Chinese population associated with FAP.

  10. A novel pathogenic large germline deletion in adenomatous polyposis coli gene in a Chinese family with familial adenomatous polyposis

    PubMed Central

    Wang, Dan; Zhang, Xipeng; Wu, Jing; Chen, Huishuang; Wang, Yanyan; Rong, Tingting; Zhou, Yulin; Banerjee, Santasree

    2016-01-01

    Germline mutations of the APC gene are associated with an autosomal dominant precancerous condition, termed familial adenomatous polyposis (FAP). FAP is clinically manifested by the presence of multiple colorectal adenomas or polyps. Gradually, these colorectal adenomas or polyps inevitably result in colorectal cancer by the third-to fourth decade of life. Surgical interventions or total proctocolectomy is the best possible treatment for FAP. Here, we present a clinical molecular study of a five generation Chinese family with FAP. Diagnosis of FAP was made on the basis of clinical manifestations, family history and medical (colonoscopy and histopathology) records. Blood samples were collected and genomic DNA was extracted. Genetic screening of the APC gene was performed by targeted next-generation sequencing and quantitative real-time PCR. Targeted next generation sequencing identified a novel heterozygous large deletion [exon5-exon16; c.423_8532del] of APC gene, which segregated with the FAP phenotypes in the proband and in all the affected family members. Unaffected family members and normal controls did not carry this deletion. In the Chinese population, most of the previously reported APC gene mutations are missense mutations. This is the first report describing the largest deletion of the APC gene in the Chinese population associated with FAP. PMID:27391059

  11. Adenomatous polyposis families that screen APC mutation-negative by conventional methods are genetically heterogeneous.

    PubMed

    Renkonen, Elise T; Nieminen, Pekka; Abdel-Rahman, Wael M; Moisio, Anu-Liisa; Järvelä, Irma; Arte, Sirpa; Järvinen, Heikki J; Peltomäki, Päivi

    2005-08-20

    One third of families with classical adenomatous polyposis (FAP), and a majority of those with attenuated FAP (AFAP), remain APC mutation-negative by conventional methods. Our purpose was to clarify the genetic basis of polyposis and genotype-phenotype correlations in such families. We studied a cohort of 29 adenomatous polyposis families that had screened APC mutation-negative by the protein truncation test, heteroduplex analysis, and exon-specific sequencing. The APC gene was investigated for large genomic rearrangements by multiplex ligation-dependent probe amplification (MLPA), and for allelic mRNA expression by single nucleotide primer extension (SNuPE). The AXIN2 gene was screened for mutations by sequencing. Four families (14%) showed a constitutional deletion of the entire APC gene (three families) or a single exon (one family). Seven families (24%) revealed reduced or extinct mRNA expression from one APC allele in blood, accompanied by loss of heterozygosity in the APC region in six (75%) of eight tumors. In 15 families (52%), possible APC involvement could be neither confirmed nor excluded. Finally, as detailed elsewhere, three families (10%) had germline mutations in genes other than APC, AXIN2 in one family, and MYH in two families. "APC mutation-negative" FAP is genetically heterogeneous, and a combination of MLPA and SNuPE is able to link a considerable proportion (38%) to APC. Significant differences were observed in clinical manifestations between subgroups, emphasizing the importance of accurate genetic and clinical characterization for the proper management of such families.

  12. ApcMin, A Mutation in the Murine Apc Gene, Predisposes to Mammary Carcinomas and Focal Alveolar Hyperplasias

    NASA Astrophysics Data System (ADS)

    Moser, Amy Rapaich; Mattes, Ellen M.; Dove, William F.; Lindstrom, Mary J.; Haag, Jill D.; Gould, Michael N.

    1993-10-01

    ApcMin (Min, multiple intestinal neoplasia) is a point mutation in the murine homolog of the APC gene. Min/+ mice develop multiple intestinal adenomas, as do humans carrying germ-line mutations in APC. Female mice carrying Min are also prone to develop mammary tumors. Min/+ mammary glands are more sensitive to chemical carcinogenesis than are +/+ mammary glands. Transplantation of mammary cells from Min/+ or +/+ donors into +/+ hosts demonstrates that the propensity to develop mammary tumors is intrinsic to the Min/+ mammary cells. Long-term grafts of Min/+ mammary glands also gave rise to focal alveolar hyperplasias, indicating that the presence of the Min mutation also has a role in the development of these lesions.

  13. Intestinal flora of FAP patients containing APC-like sequences.

    PubMed

    Hainova, K; Adamcikova, Z; Ciernikova, S; Stevurkova, V; Tyciakova, S; Zajac, V

    2014-01-01

    Colorectal cancer mortality is one of the most common cause of cancer-related mortality. A multiple risk factors are associated with colorectal cancer, including hereditary, enviromental and inflammatory syndromes affecting the gastrointestinal tract. Familial adenomatous polyposis (FAP) is characterized by the emergence of hundreds to thousands of colorectal adenomatous polyps and FAP syndrome is caused by mutations within the adenomatous polyposis coli (APC) tumor suppressor gene. We analyzed 21 rectal bacterial subclones isolated from FAP patient 41-1 with confirmed 5bp ACAAA deletion within codons 1060-1063 for the presence of APC-like sequences in longest exon 15. The studied section was defined by primers 15Efor-15Erev, what correlates with mutation cluster region (MCR) in which the 75% of all APC germline mutations were detected. More than 90% homology was showed by sequencing and subsequent software comparison. The expression of APC-like sequences was demostrated by Western blot analysis using monoclonal and polyclonal antibodies against APC protein. To study missing link between the DNA analysis (PCR, DNA sequencing) and protein expresion experiments (Western blotting) we analyzed bacterial transcripts containing the 15Efor-15Erev sequence of APC gene by reverse transcription-PCR, what indicated that an APC gene derived fragment may be produced. We observed 97-100 % homology after computer comparison of cDNA PCR products. Our results suggest that presence of APC-like sequences in intestinal/rectal bacteria is enrichment of bacterial genetic information in which horizontal gene transfer between humans and microflora play an important role.

  14. Lampe1: an ENU-germline mutation causing spontaneous hepatosteatosis identified through targeted exon-enrichment and next-generation sequencing.

    PubMed

    Sheridan, Rachel; Lampe, Kristin; Shanmukhappa, Shiva Kumar; Putnam, Patrick; Keddache, Mehdi; Divanovic, Senad; Bezerra, Jorge; Hoebe, Kasper

    2011-01-01

    Using a small scale ENU mutagenesis approach we identified a recessive germline mutant, designated Lampe1 that exhibited growth retardation and spontaneous hepatosteatosis. Low resolution mapping based on 20 intercrossed Lampe1 mice revealed linkage to a ∼14 Mb interval on the distal site of chromosome 11 containing a total of 285 genes. Exons and 50 bp flanking sequences within the critical region were enriched with sequence capture microarrays and subsequently analyzed by next-generation sequencing. Using this approach 98.1 percent of the targeted DNA was covered with a depth of 10 or more reads per nucleotide and 3 homozygote mutations were identified. Two mutations represented intronic nucleotide changes whereas one mutation affected a splice donor site in intron 11-12 of Palmitoyl Acetyl-coenzyme A oxygenase-1 (Acox1), causing skipping of exon 12. Phenotyping of Acox1(Lampe1) mutants revealed a progression from hepatosteatosis to steatohepatitis, and ultimately hepatocellular carcinoma. The current approach provides a highly efficient and affordable method to identify causative mutations induced by ENU mutagenesis and animal models relevant to human pathology.

  15. Functional studies of a novel germline p53 splicing mutation identified in a patient with Li-Fraumeni-like syndrome.

    PubMed

    Piao, Jinhua; Sakurai, Naoto; Iwamoto, Shotaro; Nishioka, Junji; Nakatani, Kaname; Komada, Yoshihiro; Mizutani, Shuki; Takagi, Masatoshi

    2013-10-01

    Most p53 mutations identified in Li-Fraumeni syndrome (LFS) are missense mutations; splicing mutations have rarely been reported. A novel splicing p53 mutation was identified in a patient with Li-Fraumeni-like syndrome (LFL). Usually, p53 missense mutants identified in LFS and cancer cells function as dominant negative mutations interfering with wild-type p53 function. However, the mechanism by which p53 haploinsufficiency causes carcinogenesis is not well characterized. In this study, we describe a novel splicing mutation that results in the loss-of-function of p53. These findings suggest a linkage between the loss-of-function type p53 mutation and a LFL phenotype.

  16. Germline TP53 Mutations in Patients With Early-Onset Colorectal Cancer in the Colon Cancer Family Registry.

    PubMed

    Yurgelun, Matthew B; Masciari, Serena; Joshi, Victoria A; Mercado, Rowena C; Lindor, Noralane M; Gallinger, Steven; Hopper, John L; Jenkins, Mark A; Buchanan, Daniel D; Newcomb, Polly A; Potter, John D; Haile, Robert W; Kucherlapati, Raju; Syngal, Sapna

    2015-05-01

    Li-Fraumeni syndrome, usually characterized by germline TP53 mutations, is associated with markedly elevated lifetime risks of multiple cancers, and has been linked to an increased risk of early-onset colorectal cancer. To examine the frequency of germline TP53 alterations in patients with early-onset colorectal cancer. This was a multicenter cross-sectional cohort study of individuals recruited to the Colon Cancer Family Registry (CCFR) from 1998 through 2007 (genetic testing data updated as of January 2015). Both population-based and clinic-based patients in the United States, Canada, Australia, and New Zealand were recruited to the CCFR. Demographic information, clinical history, and family history data were obtained at enrollment. Biospecimens were collected from consenting probands and families, including microsatellite instability and DNA mismatch repair immunohistochemistry results. A total of a 510 individuals diagnosed as having colorectal cancer at age 40 years or younger and lacking a known hereditary cancer syndrome were identified from the CCFR as being potentially eligible. Fifty-three participants were excluded owing to subsequent identification of germline mutations in DNA mismatch repair genes (n = 47) or biallelic MUTYH mutations (n = 6). Germline sequencing of the TP53 gene was performed. Identified TP53 alterations were assessed for pathogenicity using literature and international mutation database searches and in silico prediction models. Frequency of nonsynonymous germline TP53 alterations. Among 457 eligible participants (314, population-based; 143, clinic-based; median age at diagnosis, 36 years [range, 15-40 years]), 6 (1.3%; 95% CI, 0.5%-2.8%) carried germline missense TP53 alterations, none of whom met clinical criteria for Li-Fraumeni syndrome. Four of the identified TP53 alterations have been previously described in the literature in probands with clinical features of Li-Fraumeni syndrome, and 2 were novel alterations. In a

  17. Germline TP53 Mutations in Patients With Early-Onset Colorectal Cancer in the Colon Cancer Family Registry

    PubMed Central

    Yurgelun, Matthew B.; Masciari, Serena; Joshi, Victoria A.; Mercado, Rowena C.; Lindor, Noralane M.; Gallinger, Steven; Hopper, John L.; Jenkins, Mark A.; Buchanan, Daniel D.; Newcomb, Polly A.; Potter, John D.; Haile, Robert W.; Kucherlapati, Raju; Syngal, Sapna

    2015-01-01

    IMPORTANCE Li-Fraumeni syndrome, usually characterized by germline TP53 mutations, is associated with markedly elevated lifetime risks of multiple cancers, and has been linked to an increased risk of early-onset colorectal cancer. OBJECTIVE To examine the frequency of germline TP53 alterations in patients with early-onset colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This was a multicenter cross-sectional cohort study of individuals recruited to the Colon Cancer Family Registry (CCFR) from 1998 through 2007 (genetic testing data updated as of January 2015). Both population-based and clinic-based patients in the United States, Canada, Australia, and New Zealand were recruited to the CCFR. Demographic information, clinical history, and family history data were obtained at enrollment. Biospecimens were collected from consenting probands and families, including microsatellite instability and DNA mismatch repair immunohistochemistry results. A total of a 510 individuals diagnosed as having colorectal cancer at age 40 years or younger and lacking a known hereditary cancer syndrome were identified from the CCFR as being potentially eligible. Fifty-three participants were excluded owing to subsequent identification of germline mutations in DNA mismatch repair genes (n = 47) or biallelic MUTYH mutations (n = 6). INTERVENTIONS Germline sequencing of the TP53 gene was performed. Identified TP53 alterations were assessed for pathogenicity using literature and international mutation database searches and in silico prediction models. MAIN OUTCOMES AND MEASURES Frequency of nonsynonymous germline TP53 alterations. RESULTS Among 457 eligible participants (314, population-based; 143, clinic-based; median age at diagnosis, 36 years [range, 15–40 years]), 6 (1.3%; 95%CI, 0.5%–2.8%) carried germline missense TP53 alterations, none of whom met clinical criteria for Li-Fraumeni syndrome. Four of the identified TP53 alterations have been previously described in the literature

  18. A distinct mutation on the alternative splice site of APC exon 9 results in attenuated familial adenomatous polyposis phenotype.

    PubMed

    Fostira, Florentia; Yannoukakos, Drakoulis

    2010-09-01

    A subset of APC mutation carriers shows a milder familial adenomatous polyposis phenotype (attenuated FAP) developing smaller number of polyps and colorectal cancer at an older age. It seems that a different mechanism to carcinogenesis is initiated according to the initial site of the germline mutation. The APC gene of a female patient with AFAP phenotypic features was analysed. A novel mutation located on the alternatively splice site of exon 9 was identified. This is the first reported mutation in the specific site. Transcripts characterization revealed disruption of splicing occurring within exon 9, resulting in the expression of a shorter mRNA transcript, which surprisingly does not affect the ratio between the two wild type transcripts, as well as the production of wild type short isoform by the mutant allele. The short wild type isoform, produced by the mutant allele, needs to be inactivated, on top of the wild type allele, for colorectal cancer to develop. These observations enhance the 'three hit hypothesis' and indicate that a distinct mechanism for the adenoma to carcinoma sequence should be followed, for truncated mutations taking place on the borderline of the alternatively spliced exon 9 of the APC gene, as well.

  19. Aldosterone-Producing Adenoma With a Somatic KCNJ5 Mutation Revealing APC-Dependent Familial Adenomatous Polyposis.

    PubMed

    Vouillarmet, Julien; Fernandes-Rosa, Fabio; Graeppi-Dulac, Julia; Lantelme, Pierre; Decaussin-Petrucci, Myriam; Thivolet, Charles; Peix, Jean-Louis; Boulkroun, Sheerazed; Clauser, Eric; Zennaro, Maria-Christina

    2016-11-01

    Recurrent somatic mutations in KCNJ5, CACNA1D, ATP1A1, and ATP2B3 have been identified in aldosterone-producing adenomas (APAs). The question as to whether they are responsible for both nodulation and aldosterone production is not solved. We describe the case of a young patient who was diagnosed with severe arterial hypertension due to primary aldosteronism at age 26 years, followed by hemorrhagic stroke 4 years later. Abdominal computed tomography showed bilateral macronodular adrenal hyperplasia. Identification of lateralized aldosterone secretion led to right adrenalectomy, followed by normalization of biochemical and hormonal parameters and amelioration of blood pressure. The resected adrenal showed three nodules, one of them expressing aldosterone synthase and harboring a somatic KNCJ5 mutation. A Weiss revisited index of 3 of the APA prompted us to perform a second 18F-2-fluoro-2-deoxy-D-glucose-positron emission tomography after surgery, which revealed abnormal rectal activity despite the absence of clinical symptoms. Gastrointestinal exploration showed multiple polyps with severe dysplasia, and the diagnosis of familial adenomatous polyposis was established in the presence of a germline heterozygous APC gene mutation. Sequencing of somatic DNA from the APA and a second adrenal nodule revealed biallelic APC inactivation due to loss of heterozygosity in both nodules. This case report underlines the need for establishing the frequency of germline APC variants in patients with primary aldosteronism and bilateral macronodular adrenal hyperplasia because their presence may predispose to APA development and severe hypertension well before the first familial adenomatous polyposis symptoms appear. From a mechanistic point of view, it supports a two-hit model for APA development, whereby the first hit drives increased cell proliferation whereas the second hit specifies the pattern of hormonal secretion.

  20. Correlation between mutations and mRNA expression of APC and MUTYH genes: new insight into hereditary colorectal polyposis predisposition.

    PubMed

    Aceto, Gitana Maria; Fantini, Fabiana; De Iure, Sabrina; Di Nicola, Marta; Palka, Giandomenico; Valanzano, Rosa; Di Gregorio, Patrizia; Stigliano, Vittoria; Genuardi, Maurizio; Battista, Pasquale; Cama, Alessandro; Curia, Maria Cristina

    2015-10-28

    Transcript dosage imbalance may influence the transcriptome. To gain insight into the role of altered gene expression in hereditary colorectal polyposis predisposition, in the present study we analyzed absolute and allele-specific expression (ASE) of adenomatous polyposis coli (APC) and mutY Homolog (MUTYH) genes. We analyzed DNA and RNA extracted from peripheral blood mononuclear cells (PBMC) of 49 familial polyposis patients and 42 healthy blood donors selected according similar gender and age. Patients were studied for germline alterations in both genes using dHPLC, MLPA and automated sequencing. APC and MUTYH mRNA expression levels were investigated by quantitative Real-Time PCR (qRT-PCR) analysis using TaqMan assay and by ASE assays using dHPLC-based primer extension. Twenty out of 49 patients showed germline mutations: 14 in APC gene and six in MUTYH gene. Twenty-nine patients did not show mutations in both genes. Results from qRT-PCR indicated that gene expression of both APC and MUTYH was reduced in patients analyzed. In particular, a significant reduction in APC expression was observed in patients without APC germline mutation vs control group (P < 0.05) while APC expression in the mutation carrier patients, although lower compared to control individuals, did not show statistical significance. On the other hand a significant reduced MUTYH expression was detected in patients with MUTYH mutations vs control group (P < 0.05). Altered ASE of APC was detected in four out of eight APC mutation carriers. In particular one case showed a complete loss of one allele. Among APC mutation negative cases, 4 out of 13 showed a moderate ASE. ASE of MUTYH did not show any altered expression in the cases analyzed. Spearman's Rho Test analysis showed a positive and significant correlation between APC and MUTYH genes both in cases and in controls (P = 0.020 and P < 0.001). APC and MUTYH showed a reduced germline expression, not always corresponding to gene

  1. Selective targeting of mutant adenomatous polyposis coli (APC) in colorectal cancer.

    PubMed

    Zhang, Lu; Theodoropoulos, Panayotis C; Eskiocak, Ugur; Wang, Wentian; Moon, Young-Ah; Posner, Bruce; Williams, Noelle S; Wright, Woodring E; Kim, Sang Bum; Nijhawan, Deepak; De Brabander, Jef K; Shay, Jerry W

    2016-10-19

    Mutations in the adenomatous polyposis coli (APC) gene are common in colorectal cancer (CRC), and more than 90% of those mutations generate stable truncated gene products. We describe a chemical screen using normal human colonic epithelial cells (HCECs) and a series of oncogenically progressed HCECs containing a truncated APC protein. With this screen, we identified a small molecule, TASIN-1 (truncated APC selective inhibitor-1), that specifically kills cells with APC truncations but spares normal and cancer cells with wild-type APC. TASIN-1 exerts its cytotoxic effects through inhibition of cholesterol biosynthesis. In vivo administration of TASIN-1 inhibits tumor growth of CRC cells with truncated APC but not APC wild-type CRC cells in xenograft models and in a genetically engineered CRC mouse model with minimal toxicity. TASIN-1 represents a potential therapeutic strategy for prevention and intervention in CRC with mutant APC.

  2. Adrenocortical tumors associated with the TP53 p.R337H germline mutation can be identified during child-care consultations.

    PubMed

    Mastellaro, Maria J; Ribeiro, Raul C; Oliveira-Filho, Antônio G; Seidinger, Ana L; Cardinalli, Izilda A; Miranda, Eliana C M; Aguiar, Simone S; Brandalise, Silvia R; Yunes, José A; Barros-Filho, Antônio A

    2017-08-30

    To evaluate the clinical features associated with adrenocortical hormone overexpression and familial cancer profiling as potential markers for early detection of adrenocortical tumors in children from South and Southeast Brazil. The clinical manifestations and anthropometric measurements of 103 children diagnosed with adrenocortical tumors were analyzed. Between 1982 and 2011, 69 girls and 34 boys diagnosed with adrenocortical tumors were followed-up for a median time of 9.0 years (0-34 years). Signs of androgen overproduction alone (n=75) or associated with cortisol (n=18) were present in 90.3%. TP53 p.R337H mutation was found in 90.5% of patients. Stages I, II, III, and IV were observed in 45.6%, 27.2%, 19.4%, and 7.8% of patients, respectively. At diagnosis, there were no significant differences in height (p=0.92) and weight (p=0.22) among children with adrenocortical tumors, but children with virilization alone had significantly higher height-for-age Z-scores (0.92±1.4) than children with hypercortisolism alone or combined (-0.32±1.8; p=0.03). The five-year overall survival was 76.7% (SD±4.2). Patients with advanced-stage disease had a significantly worse prognosis than those with limited disease (p<0.001). During follow-up, ten of 55 p.R337H carrier parents developed cancer, whereas none of the 55 non-carriers did. Signs of adrenocortical hormone overproduction appear early, even in cases with early-stage. These signs can be identified at the physical examination and anthropometric measurements. In southern Brazil, pediatric adrenocortical tumor is a sentinel cancer for detecting families with germline p.R337H mutation in TP53 gene. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  3. PTT analysis of polyps from FAP patients reveals a great majority of APC truncating mutations

    SciTech Connect

    Luijt, R.B. van der; Khan, P.M.; Tops, C.M.J.

    1994-09-01

    The adenomatous polyposis coli (APC) gene plays an important role in colorectal carcinogenesis. Germline APC mutations are associated with familial adenomatous polyposis (FAP), an autosomal dominantly inherited predisposition to colorectal cancer, characterized by the development of numerous adenomatous polyps in the large intestine. In order to investigate whether somatic inactivation of the remaining APC allele is necessary for adenoma formation, we collected multiple adenomatous polyps from individual FAP patients and investigated the presence of somatic mutations in the APC gene. The analysis of somatic APC mutations in these tumor samples was performed using a rapid and sensitive assay, called the protein truncation test (PTT). Chain-terminating somatic APC mutations were detected in the great majority of the tumor samples investigated. As expected, these mutations were mainly located in the mutation cluster region (MCR) in exon 15. Our results confirm that somatic mutation of the second APC allele is required for adenoma formation in FAP. Interestingly, in the polyps investigated in our study, the second APC allele is somatically inactivated through point mutation leading to a stop codon rather than by loss of heterozygosity. The observation that somatic second hits in APC are required for tumor development in FAP is in apparent accordance with the Knudson hypothesis for classical tumor suppressor genes. However, it is yet unknown whether chain-terminating APC mutations lead to a truncated protein exerting a dominant-negative effect or whether these mutations result in a null allele. Further investigation of this important issue will hopefully provide a better understanding of the mechanism of action of the mutated APC alleles in colorectal carcinogenesis.

  4. Germline mutation in BRAF codon 600 is compatible with human development: de novo p.V600G mutation identified in a patient with CFC syndrome.

    PubMed

    Champion, K J; Bunag, C; Estep, A L; Jones, J R; Bolt, C H; Rogers, R C; Rauen, K A; Everman, D B

    2011-05-01

    BRAF, the protein product of BRAF, is a serine/threonine protein kinase and one of the direct downstream effectors of Ras. Somatic mutations in BRAF occur in numerous human cancers, whereas germline BRAF mutations cause cardio-facio-cutaneous (CFC) syndrome. One recurrent somatic mutation, p.V600E, is frequently found in several tumor types, such as melanoma, papillary thyroid carcinoma, colon cancer, and ovarian cancer. However, a germline mutation affecting codon 600 has never been described. Here, we present a patient with CFC syndrome and a de novo germline mutation involving codon 600 of BRAF, thus providing the first evidence that a pathogenic germline mutation involving this critical codon is not only compatible with development but can also cause the CFC phenotype. In vitro functional analysis shows that this mutation, which replaces a valine with a glycine at codon 600 (p.V600G), leads to increased ERK and ELK phosphorylation compared to wild-type BRAF but is less strongly activating than the cancer-associated p.V600E mutation. © 2010 John Wiley & Sons A/S.

  5. A CA-repeat polymorphism close to the adenomatous polyposis coli (APC) gene offers improved diagnostic testing for familial APC

    SciTech Connect

    Spirio, L.; Nelson, L.; Ward, K.; Burt, R.; White, R.; Leppert, M. )

    1993-02-01

    Presymptomatic genetic testing for the presence of a mutant allele causing familial adenomatous polyposis coli (APC) has been difficult to perform effectively in the past because DNA markers surrounding the APC gene on chromosome 5q have not been very informative. The authors report results of genetic linkage studies on both research families and clinical families by using D5S346, a highly polymorphic dinucleotide (CA)-repeat locus 30-70 kb from the APC gene. Linkage analysis with this marker in a large APC pedigree showed an increase of at least 9.0 LOD units, in likelihood of linkage of the disease-causing allele to the APC locus, when compared with the highest LOD score attained with any other closely linked marker. When the first 14 APC families that requested genotypic analysis by the DNA Diagnostic Laboratory at the University of Utah were tested with D5S346, 20 of the 31 at-risk individuals were identified as either carriers or noncarriers of an APC-predisposing allele. The authors see this marker as an important tool for research studies and for the presymptomatic diagnosis of APC. 28 refs., 3 figs., 2 tabs.

  6. Wild-type APC predicts poor prognosis in microsatellite-stable proximal colon cancer

    PubMed Central

    Jorissen, Robert N; Christie, Michael; Mouradov, Dmitri; Sakthianandeswaren, Anuratha; Li, Shan; Love, Christopher; Xu, Zheng-Zhou; Molloy, Peter L; Jones, Ian T; McLaughlin, Stephen; Ward, Robyn L; Hawkins, Nicholas J; Ruszkiewicz, Andrew R; Moore, James; Burgess, Antony W; Busam, Dana; Zhao, Qi; Strausberg, Robert L; Lipton, Lara; Desai, Jayesh; Gibbs, Peter; Sieber, Oliver M

    2015-01-01

    Background: APC mutations (APC-mt) occur in ∼70% of colorectal cancers (CRCs), but their relationship to prognosis is unclear. Methods: APC prognostic value was evaluated in 746 stage I–IV CRC patients, stratifying for tumour location and microsatellite instability (MSI). Microarrays were used to identify a gene signature that could classify APC mutation status, and classifier ability to predict prognosis was examined in an independent cohort. Results: Wild-type APC microsatellite stable (APC-wt/MSS) tumours from the proximal colon showed poorer overall and recurrence-free survival (OS, RFS) than APC-mt/MSS proximal, APC-wt/MSS distal and APC-mt/MSS distal tumours (OS HR⩾1.79, P⩽0.015; RFS HR⩾1.88, P⩽0.026). APC was a stronger prognostic indicator than BRAF, KRAS, PIK3CA, TP53, CpG island methylator phenotype or chromosomal instability status (P⩽0.036). Microarray analysis similarly revealed poorer survival in MSS proximal cancers with an APC-wt-like signature (P=0.019). APC status did not affect outcomes in MSI tumours. In a validation on 206 patients with proximal colon cancer, APC-wt-like signature MSS cases showed poorer survival than APC-mt-like signature MSS or MSI cases (OS HR⩾2.50, P⩽0.010; RFS HR⩾2.14, P⩽0.025). Poor prognosis APC-wt/MSS proximal tumours exhibited features of the sessile serrated neoplasia pathway (P⩽0.016). Conclusions: APC-wt status is a marker of poor prognosis in MSS proximal colon cancer. PMID:26305864

  7. CDH1 germ-line missense mutation identified by multigene sequencing in a family with no history of diffuse gastric cancer.

    PubMed

    Lajus, Tirzah Braz Petta; Sales, Roberto Magnus Duarte

    2015-09-01

    Germ-line mutation in CDH1 gene is associated with high risk for Hereditary Diffuse Gastric Cancer (HDGC) and Infiltrative Lobular Carcinoma (ILC). Although somatic CDH1 mutations were also detected in ILC with a frequency ranging from 10 to 56%, CDH1 alterations in more frequent infiltrative ductal carcinoma (IDC) appear to be rare, and no association with germ-line CDH1 mutation and IDC has been established. Here we report the case of a woman diagnosed with IDC at 39years of age, presenting extensive familial history of cancer at multiple sites with early-age onset and with no case of HDGC. Deep sequencing have revealed CDH1 missense mutation c.1849G>A (p.Ala617Thr) in heterozygous and four BRCA2 single nucleotide polymorphism in homozygosis. In this family, the mutation c.1849G>A in the CDH1 gene is not related to HDGC nor ILC. Therefore, here we highlight that multigene analysis is important to detect germ-line mutations and genetic variants in patients with cancers at multiple sites in the family, even if inconclusive genetic counseling can be offered, since hereafter, medical awareness will be held.

  8. Alternatively spliced adenomatous polyposis coli (APC) gene transcripts that delete exons mutated in attenuated APC.

    PubMed

    Samowitz, W S; Thliveris, A; Spirio, L N; White, R

    1995-09-01

    Reverse transcription-PCR combined with either (a) restriction enzyme digestion and repeat PCR or (b) ligase chain reaction has identified two new alternatively spliced transcripts of the adenomatous polyposis coli (APC) gene. In one of these transcripts exons 1-4 and the first 16 bases of exon 5 are deleted; in the other exons 2-4 and the first 16 bases of 5 are deleted. Both transcripts use an intraexonic splice acceptor in exon 5. These transcripts delete exons mutated in attenuated APC (3 and 4) and could account for the reduction in severity of this variant.

  9. APC-like congenital hypertrophy of the retinal pigment epithelium (CHRPE) in non-APC patients: Evidence for autosomal dominant transmission in one family

    SciTech Connect

    Thonney, E.; Munier, F.L. Pescia, G.

    1994-09-01

    The presence of congenital hypertrophy of the retinal pigment epithelium (CHRPE) is known to be the earliest phenotypic marker in carriers of a mutant allele of the adenomatous polyposis coli gene (APC). The specificity of CHRPE is known to be over 97%, provided that the lesions are bilateral and their total number higher than 4. In the present study, we describe 3 patients from 2 unrelated families with bilateral multiple asymptomatic CHRPE (8-17), normal visual function and no family history of APC. Clinical examination failed to detect other extracolonic signs of APC nor did a search for adenomatous polyps by colonscopy. In one family, the ocular phenotype was transmitted from a father to his only son. Mutation hot spots at codons 302, 622, 625, 1061 and 1309 of the APC gene (about 25% of germline mutations) were all tested normal. We postulate that these APC-free ocular findings reflect the allelic involvement of a mutant APC allele that remains to be characterized. However, involvement of another yet unrecognized autosomal dominant gene cannot be ruled out and additional families with this unique trait should be studied.

  10. Somatic APC inactivation mechanisms in sporadic colorectal cancer cases in Hungary.

    PubMed

    Kámory, Eniko; Olasz, Judit; Csuka, Orsolya

    2008-03-01

    The role of germline inactivation of the adenomatosis polyposis coli (APC) gene in hereditary colorectal cancer is well known, being the most important cause of familial adenomatosus polyposis (FAP) syndrome. Hereditary cases with germline mutations, however, account only for 5-10% of colorectal cancers. The somatic inactivation of this gene has also been observed in sporadic cases. In order to examine the inactivation mechanisms of the APC gene we screened 70 sporadic colorectal cancer cases (27 rectal, 43 intestinal) of different stages for promoter hypermethylation, allelic imbalance (AI) and somatic mutations. The presence of promoter hypermethylation was observed in 21 cases (30%). Fifteen of the examined tumors (21%) showed AI, and also 15 tumors (21%) carried at least one somatic mutation. Thirteen of the detected alterations were novel variations: seven frameshifts, four missense mutations and two polymorphisms. Biallelic inactivation was found in 15 patients (21%). These results suggest that the inactivation of the APC gene is very common in sporadic colorectal cancer, and the main inactivation mechanism of the APC gene is promoter hypermethylation. Allelic imbalance has the same frequency as mutations, and mutations in the APC gene are more common in the early stages and in tumors located in the rectum.

  11. Suppressors of spindle checkpoint defect (such) mutants identify new mdf-1/MAD1 interactors in Caenorhabditis elegans.

    PubMed

    Tarailo, Maja; Kitagawa, Risa; Rose, Ann M

    2007-04-01

    The spindle assembly checkpoint (SAC) governs the timing of metaphase-to-anaphase transition and is essential for genome stability. The Caenorhabditis elegans mutant strain gk2 carries a deletion within the mdf-1/MAD1 gene that results in death of the homozygous strain after two or three generations. Here we describe 11 suppressors of the mdf-1(gk2) lethality, 10 identified in an ethyl methanesulfonate (EMS) mutagenesis screen and 1 isolated using the dog-1(gk10) (deletions of guanine-rich DNA) mutator strain. Using time-lapse imaging of early embryonic cells and germline mitotic division, we demonstrate that there are two classes of suppressors. Eight suppressors compensate for the loss of the checkpoint by delaying mitotic progression, which coincides with securin (IFY-1/Pds1) accumulation; three suppressors have normal IFY-1/Pds1 levels and normal anaphase onset. Furthermore, in the class of suppressors with delayed mitotic progression, we have identified four alleles of known suppressors emb-30/APC4 and fzy-1/CDC20, which are components of the anaphase-promoting complex/cyclosome (APC/C). In addition, we have identified another APC/C component capable of bypassing the checkpoint requirement that has not previously been described in C. elegans. The such-1/APC5-like mutation, h1960, significantly delays anaphase onset both in germline and in early embryonic cells.

  12. Suppressors of Spindle Checkpoint Defect (such) Mutants Identify New mdf-1/MAD1 Interactors in Caenorhabditis elegans

    PubMed Central

    Tarailo, Maja; Kitagawa, Risa; Rose, Ann M.

    2007-01-01

    The spindle assembly checkpoint (SAC) governs the timing of metaphase-to-anaphase transition and is essential for genome stability. The Caenorhabditis elegans mutant strain gk2 carries a deletion within the mdf-1/MAD1 gene that results in death of the homozygous strain after two or three generations. Here we describe 11 suppressors of the mdf-1(gk2) lethality, 10 identified in an ethyl methanesulfonate (EMS) mutagenesis screen and 1 isolated using the dog-1(gk10) (deletions of guanine-rich DNA) mutator strain. Using time-lapse imaging of early embryonic cells and germline mitotic division, we demonstrate that there are two classes of suppressors. Eight suppressors compensate for the loss of the checkpoint by delaying mitotic progression, which coincides with securin (IFY-1/Pds1) accumulation; three suppressors have normal IFY-1/Pds1 levels and normal anaphase onset. Furthermore, in the class of suppressors with delayed mitotic progression, we have identified four alleles of known suppressors emb-30/APC4 and fzy-1/CDC20, which are components of the anaphase-promoting complex/cyclosome (APC/C). In addition, we have identified another APC/C component capable of bypassing the checkpoint requirement that has not previously been described in C. elegans. The such-1/APC5-like mutation, h1960, significantly delays anaphase onset both in germline and in early embryonic cells. PMID:17237515

  13. The Anaphase-Promoting Complex (APC) ubiquitin ligase affects chemosensory behavior in C. elegans

    PubMed Central

    Wang, Julia; Jennings, Alexandra K.

    2016-01-01

    The regulation of fundamental aspects of neurobiological function has been linked to the ubiquitin signaling system (USS), which regulates the degradation and activity of proteins and is catalyzed by E1, E2, and E3 enzymes. The Anaphase-Promoting Complex (APC) is a multi-subunit E3 ubiquitin ligase that controls diverse developmental and signaling processes in post-mitotic neurons; however, potential roles for the APC in sensory function have yet to be explored. In this study, we examined the effect of the APC ubiquitin ligase on chemosensation in Caenorhabditis elegans by testing chemotaxis to the volatile odorants, diacetyl, pyrazine, and isoamyl alcohol, to which wild-type worms are attracted. Animals with loss of function mutations in either of two alleles (g48 and ye143) of the gene encoding the APC subunit EMB-27 APC6 showed increased chemotaxis towards diacetyl and pyrazine, odorants sensed by AWA neurons, but exhibited normal chemotaxis to isoamyl alcohol, which is sensed by AWC neurons. The statistically significant increase in chemotaxis in the emb-27 APC6 mutants suggests that the APC inhibits AWA-mediated chemosensation in C. elegans. Increased chemotaxis to pyrazine was also seen with mutants lacking another essential APC subunit, MAT-2 APC1; however, mat-2 APC1 mutants exhibited wild type responses to diacetyl. The difference in responsiveness of these two APC subunit mutants may be due to differential strength of these hypomorphic alleles or may indicate the presence of functional sub-complexes of the APC at work in this process. These findings are the first evidence for APC-mediated regulation of chemosensation and lay the groundwork for further studies aimed at identifying the expression levels, function, and targets of the APC in specific sensory neurons. Because of the similarity between human and C. elegans nervous systems, the role of the APC in sensory neurons may also advance our understanding of human sensory function and disease. PMID

  14. A multigene mutation classification of 468 colorectal cancers reveals a prognostic role for APC

    PubMed Central

    Schell, Michael J.; Yang, Mingli; Teer, Jamie K.; Lo, Fang Yin; Madan, Anup; Coppola, Domenico; Monteiro, Alvaro N. A.; Nebozhyn, Michael V.; Yue, Binglin; Loboda, Andrey; Bien-Willner, Gabriel A.; Greenawalt, Danielle M.; Yeatman, Timothy J.

    2016-01-01

    Colorectal cancer (CRC) is a highly heterogeneous disease, for which prognosis has been relegated to clinicopathologic staging for decades. There is a need to stratify subpopulations of CRC on a molecular basis to better predict outcome and assign therapies. Here we report targeted exome-sequencing of 1,321 cancer-related genes on 468 tumour specimens, which identified a subset of 17 genes that best classify CRC, with APC playing a central role in predicting overall survival. APC may assume 0, 1 or 2 truncating mutations, each with a striking differential impact on survival. Tumours lacking any APC mutation carry a worse prognosis than single APC mutation tumours; however, two APC mutation tumours with mutant KRAS and TP53 confer the poorest survival among all the subgroups examined. Our study demonstrates a prognostic role for APC and suggests that sequencing of APC may have clinical utility in the routine staging and potential therapeutic assignment for CRC. PMID:27302369

  15. APCS — EDRN Public Portal

    Cancer.gov

    APCS, a secreted glycoprotein found in serum and urine, interacts with DNA and histones and may scavenge nuclear material released from damaged circulating cells. It is thought to control the degradation of chromatin and has been demonstrated to bind to apoptotic cells at an early stage, which raises the possibility that it is involved in dealing with apoptotic cells in vivo. APCS may also function as a calcium-dependent lectin. APCS is a member of the pentaxin family of proteins, which characteristically bind two calcium ions per subunit and have a a discoid arrangement of 5 non-covalently bound subunits.

  16. The ABBA motif binds APC/C activators and is shared by APC/C substrates and regulators

    PubMed Central

    Hagting, Anja; Izawa, Daisuke; Mansfeld, Jörg; Gibson, Toby J.; Pines, Jonathon

    2016-01-01

    The APC/C is the ubiquitin ligase that regulates mitosis by targeting specific proteins for degradation at specific times under the control of the Spindle Assembly Checkpoint (SAC). How the APC/C recognises its different substrates is a key problem in the control of cell division. Here, we have identified the ABBA motif in Cyclin A, BUBR1, BUB1 and Acm1, and show that it binds to the APC/C co-activator CDC20. The ABBA motif in Cyclin A is required for its proper degradation in prometaphase through competing with BUBR1 for the same site on CDC20. Moreover, the ABBA motifs in BUBR1 and BUB1 are necessary for the SAC to work at full strength and to recruit CDC20 to kinetochores. Thus, we have identified a conserved motif integral to the proper control of mitosis that connects APC/C substrate recognition with the SAC. PMID:25669885

  17. Comprehensive detection of germline variants by MSK-IMPACT, a clinical diagnostic platform for solid tumor molecular oncology and concurrent cancer predisposition testing.

    PubMed

    Cheng, Donavan T; Prasad, Meera; Chekaluk, Yvonne; Benayed, Ryma; Sadowska, Justyna; Zehir, Ahmet; Syed, Aijazuddin; Wang, Yan Elsa; Somar, Joshua; Li, Yirong; Yelskaya, Zarina; Wong, Donna; Robson, Mark E; Offit, Kenneth; Berger, Michael F; Nafa, Khedoudja; Ladanyi, Marc; Zhang, Liying

    2017-05-19

    The growing number of Next Generation Sequencing (NGS) tests is transforming the routine clinical diagnosis of hereditary cancers. Identifying whether a cancer is the result of an underlying disease-causing mutation in a cancer predisposition gene is not only diagnostic for a cancer predisposition syndrome, but also has significant clinical implications in the clinical management of patients and their families. Here, we evaluated the performance of MSK-IMPACT (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets) in detecting genetic alterations in 76 genes implicated in cancer predisposition syndromes. Output from hybridization-based capture was sequenced on an Illumina HiSeq 2500. A custom analysis pipeline was used to detect single nucleotide variants (SNVs), small insertions/deletions (indels) and copy number variants (CNVs). MSK-IMPACT detected all germline variants in a set of 233 unique patient DNA samples, previously confirmed by previous single gene testing. Reproducibility of variant calls was demonstrated using inter- and intra- run replicates. Moreover, in 16 samples, we identified additional pathogenic mutations other than those previously identified through a traditional gene-by-gene approach, including founder mutations in BRCA1, BRCA2, CHEK2 and APC, and truncating mutations in TP53, TSC2, ATM and VHL. This study highlights the importance of the NGS-based gene panel testing approach in comprehensively identifying germline variants contributing to cancer predisposition and simultaneous detection of somatic and germline alterations.

  18. Integrated tumor and germline whole-exome sequencing identifies mutations in MAPK and PI3K pathway genes in an adolescent with rosette-forming glioneuronal tumor of the fourth ventricle

    PubMed Central

    Lin, Frank Y.; Bergstrom, Katie; Person, Richard; Bavle, Abhishek; Ballester, Leomar Y.; Scollon, Sarah; Raesz-Martinez, Robin; Jea, Andrew; Birchansky, Sherri; Wheeler, David A.; Berg, Stacey L.; Chintagumpala, Murali M.; Adesina, Adekunle M.; Eng, Christine; Roy, Angshumoy; Plon, Sharon E.; Parsons, D. Williams

    2016-01-01

    The integration of genome-scale studies such as whole-exome sequencing (WES) into the clinical care of children with cancer has the potential to provide insight into the genetic basis of an individual's cancer with implications for clinical management. This report describes the results of clinical tumor and germline WES for a patient with a rare tumor diagnosis, rosette-forming glioneuronal tumor of the fourth ventricle (RGNT). Three pathogenic gene alterations with implications for clinical care were identified: somatic activating hotspot mutations in FGFR1 (p.N546K) and PIK3CA (p.H1047R) and a germline pathogenic variant in PTPN11 (p.N308S) diagnostic for Noonan syndrome. The molecular landscape of RGNT is not well-described, but these data are consistent with prior observations regarding the importance of the interconnected MAPK and PI3K/AKT/mTOR signaling pathways in this rare tumor. The co-occurrence of FGFR1, PIK3CA, and PTPN11 alterations provides further evidence for consideration of RGNT as a distinct molecular entity from pediatric low-grade gliomas and suggests potential therapeutic strategies for this patient in the event of tumor recurrence as novel agents targeting these pathways enter pediatric clinical trials. Although RGNT has not been definitively linked with cancer predisposition syndromes, two prior cases have been reported in patients with RASopathies (Noonan syndrome and neurofibromatosis type 1 [NF1]), providing an additional link between these tumors and the mitogen-activated protein kinase (MAPK) signaling pathway. In summary, this case provides an example of the potential for genome-scale sequencing technologies to provide insight into the biology of rare tumors and yield both tumor and germline results of potential relevance to patient care. PMID:27626068

  19. Germ-line enhancement of humans and non-humans.

    PubMed

    Loftis, J Robert

    2005-03-01

    The current difference in attitude toward germ-line enhancement in humans and nonhumans is unjustified. Society should be more cautious in modifying the genes of nonhumans and more bold in thinking about modifying our own genome. I identify four classes of arguments pertaining to germ-line enhancement: safety arguments, justice arguments, trust arguments, and naturalness arguments. The first three types are compelling, but do not distinguish between human and nonhuman cases. The final class of argument would justify a distinction between human and nonhuman germ-line enhancement; however, this type of argument fails and, therefore, the discrepancy in attitude toward human and nonhuman germ-line enhancement is unjustified.

  20. Differential RNA-seq analysis comparing APC-defective and APC-restored SW480 colorectal cancer cells.

    PubMed

    King, Lauren E; Love, Christopher G; Sieber, Oliver M; Faux, Maree C; Burgess, Antony W

    2016-03-01

    The adenomatous polyposis coli (APC) tumour suppressor gene is mutated in about 80% of colorectal cancers (CRC) Brannon et al. (2014) [1]. APC is a large multifunctional protein that regulates many biological functions including Wnt signalling (through the regulation of beta-catenin stability) Reya and Clevers (2005) [2], cell migration Kroboth et al. (2007), Sansom et al. (2004) [3], [4], mitosis Kaplan et al. (2001) [5], cell adhesion Faux et al. (2004), Carothers et al. (2001) [6], [7] and differentiation Sansom et al. (2004) [4]. Although the role of APC in CRC is often described as the deregulation of Wnt signalling, its other biological functions suggest that there are other factors at play that contribute to the onset of adenomas and the progression of CRC upon the truncation of APC. To identify genes and pathways that are dysregulated as a consequence of loss of function of APC, we compared the gene expression profiles of the APC mutated human CRC cell line SW480 following reintroduction of wild-type APC (SW480 + APC) or empty control vector (SW480 + vector control) Faux et al. (2004) . Here we describe the RNA-seq data derived for three biological replicates of parental SW480, SW480 + vector control and SW480 + APC cells, and present the bioinformatics pipeline used to test for differential gene expression and pathway enrichment analysis. A total of 1735 genes showed significant differential expression when APC was restored and were enriched for genes associated with cell polarity, Wnt signalling and the epithelial to mesenchymal transition. There was additional enrichment for genes involved in cell-cell adhesion, cell-matrix junctions, angiogenesis, axon morphogenesis and cell movement. The raw and analysed RNA-seq data have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE76307. This dataset is useful for further investigations of the impact of APC mutation on the properties of colorectal cancer cells.

  1. Differential RNA-seq analysis comparing APC-defective and APC-restored SW480 colorectal cancer cells

    PubMed Central

    King, Lauren E.; Love, Christopher G.; Sieber, Oliver M.; Faux, Maree C.; Burgess, Antony W.

    2016-01-01

    The adenomatous polyposis coli (APC) tumour suppressor gene is mutated in about 80% of colorectal cancers (CRC) Brannon et al. (2014) [1]. APC is a large multifunctional protein that regulates many biological functions including Wnt signalling (through the regulation of beta-catenin stability) Reya and Clevers (2005) [2], cell migration Kroboth et al. (2007), Sansom et al. (2004) [3], [4], mitosis Kaplan et al. (2001) [5], cell adhesion Faux et al. (2004), Carothers et al. (2001) [6], [7] and differentiation Sansom et al. (2004) [4]. Although the role of APC in CRC is often described as the deregulation of Wnt signalling, its other biological functions suggest that there are other factors at play that contribute to the onset of adenomas and the progression of CRC upon the truncation of APC. To identify genes and pathways that are dysregulated as a consequence of loss of function of APC, we compared the gene expression profiles of the APC mutated human CRC cell line SW480 following reintroduction of wild-type APC (SW480 + APC) or empty control vector (SW480 + vector control) Faux et al. (2004) . Here we describe the RNA-seq data derived for three biological replicates of parental SW480, SW480 + vector control and SW480 + APC cells, and present the bioinformatics pipeline used to test for differential gene expression and pathway enrichment analysis. A total of 1735 genes showed significant differential expression when APC was restored and were enriched for genes associated with cell polarity, Wnt signalling and the epithelial to mesenchymal transition. There was additional enrichment for genes involved in cell–cell adhesion, cell–matrix junctions, angiogenesis, axon morphogenesis and cell movement. The raw and analysed RNA-seq data have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE76307. This dataset is useful for further investigations of the impact of APC mutation on the properties of colorectal cancer cells

  2. A novel pathogenic germline mutation in the adenomatous polyposis coli gene in a Chinese family with familial adenomatous coli

    PubMed Central

    He, Long-Jun; Wang, Qi-Jing; Weng, De-Sheng; Pan, Ke; Liu, Qing; Zhao, Jing-Jing; Pan, Qiu-Zhong; Zhang, Xiao-Fei; Tang, Yan; Chen, Chang-Long; Zhang, Hong-Xia; Xu, Guo-Liang; Zeng, Yi-Xin; Xia, Jian-Chuan

    2015-01-01

    Familial adenomatous polyposis (FAP) is an autosomal dominant disease manifesting as colorectal cancer in middle-aged patients. Mutations of the adenomatous polyposis coli (APC) gene contribute to both FAP and sporadic or familial colorectal carcinogenesis. Here we describe the identification of the causative APC gene defects associated with FAP in a Chinese pedigree. All patients with FAP were diagnosed by their combination of clinical features, family history, colonoscopy, and pathology examinations. Blood samples were collected and genomic DNA was extracted. Mutation analysis of APC was conducted by targeted next-generation sequencing, long-range PCR and Sanger sequencing. A novel mutation in exon 14–15(c.1936-2148 del) and intron 14 of the APC gene was demonstrated in all FAP patients and was absent in unaffected family members. This novel deletion causing FAP in Chinese kindred expands the germline mutation spectrum of the APC gene in the Chinese population. PMID:26311738

  3. A novel pathogenic germline mutation in the adenomatous polyposis coli gene in a Chinese family with familial adenomatous coli.

    PubMed

    Jiang, Shan-Shan; Li, Jian-Jun; Li, Yin; He, Long-Jun; Wang, Qi-Jing; Weng, D Sheng; Pan, Ke; Liu, Qing; Zhao, Jing-Jing; Pan, Qiu-Zhong; Zhang, Xiao-Fei; Tang, Yan; Chen, Chang-Long; Zhang, Hong-Xia; Xu, Guo-Liang; Zeng, Yi-Xin; Xia, Jian-Chuan

    2015-09-29

    Familial adenomatous polyposis (FAP) is an autosomal dominant disease manifesting as colorectal cancer in middle-aged patients. Mutations of the adenomatous polyposis coli (APC) gene contribute to both FAP and sporadic or familial colorectal carcinogenesis. Here we describe the identification of the causative APC gene defects associated with FAP in a Chinese pedigree. All patients with FAP were diagnosed by their combination of clinical features, family history, colonoscopy, and pathology examinations. Blood samples were collected and genomic DNA was extracted. Mutation analysis of APC was conducted by targeted next-generation sequencing, long-range PCR and Sanger sequencing. A novel mutation in exon 14-15(c.1936-2148 del) and intron 14 of the APC gene was demonstrated in all FAP patients and was absent in unaffected family members. This novel deletion causing FAP in Chinese kindred expands the germline mutation spectrum of the APC gene in the Chinese population.

  4. Characteristics of Germline and Non-germline Retinoblastomas

    PubMed Central

    Ghassemi, Fariba; Chams, Hormoz; Sabour, Siamak; Karkhaneh, Reza; Farzbod, Farzad; Khodaparast, Mehdi; Vosough, Parvaneh

    2014-01-01

    Purpose To discuss the clinical characteristics, treatment and outcomes of germline and non-germline retinoblastoma tumors. Methods A retrospective study was performed on retinoblastoma cases from 1979 to 2007. General characteristics of the patients, treatment modalities, histopathological findings and survival were compared in germline versus non-germline cases. Results We analyzed 557 cases of retinoblastoma with mean age of 32.2±22.0 months including 177 and 380 patients with germline and non-germline tumors, respectively. Germline cases were significantly different from non-germline counterparts in terms of mean age (24.7±17.7 vs 35.7±23.0 months), symptoms (leukocoria in 49.4% vs 62.9%), and outcomes (death in 40.1% vs 13.9%), respectively (P<0.001). In the germline group 66.5% and in non-germline group over 97% of patients had stage Va or higher (ICRB D-E disease). Disease-free survival was 48.6% for germlines cases versus 80.9% for non-germline patients (with mean follow up of 61.9 months, P<0.001). Histopathologically, more invasions to intraocular and extraocular tissues were seen with non-germline tumors of (66% vs 39.8%). Mortality rates in germline cases and non-germline were 40.1% and 13.9%, respectively (P<0.001). Conclusion Despite higher tumor staging in nongermline cases at the time of diagnosis and therefore more aggressive behavior of the tumor, germline cases had a higher rate of mortality during the follow up period. PMID:25279120

  5. The APC variants I1307K and E1317Q are associated with colorectal tumors, but not always with a family history

    PubMed Central

    Frayling, Ian M.; Beck, Nicholas E.; Ilyas, Mohammad; Dove-Edwin, Isis; Goodman, Peter; Pack, Kevin; Bell, Jennifer A.; Williams, Christopher B.; Hodgson, Shirley V.; Thomas, Huw J. W.; Talbot, Ian C.; Bodmer, Walter F.; Tomlinson, Ian P. M.

    1998-01-01

    Classical familial adenomatous polyposis (FAP) is a high-penetrance autosomal dominant disease that predisposes to hundreds or thousands of colorectal adenomas and carcinoma and that results from truncating mutations in the APC gene. A variant of FAP is attenuated adenomatous polyposis coli, which results from germ-line mutations in the 5′ and 3′ regions of the APC gene. Attenuated adenomatous polyposis coli patients have “multiple” colorectal adenomas (typically fewer than 100) without the florid phenotype of classical FAP. Another group of patients with multiple adenomas has no mutations in the APC gene, and their phenotype probably results from variation at a locus, or loci, elsewhere in the genome. Recently, however, a missense variant of APC (I1307K) was described that confers an increased risk of colorectal tumors, including multiple adenomas, in Ashkenazim. We have studied a set of 164 patients with multiple colorectal adenomas and/or carcinoma and analyzed codons 1263–1377 (exon 15G) of the APC gene for germ-line variants. Three patients with the I1307K allele were detected, each of Ashkenazi descent. Four patients had a germ-line E1317Q missense variant of APC that was not present in controls; one of these individuals had an unusually large number of metaplastic polyps of the colorectum. There is increasing evidence that there exist germ-line variants of the APC gene that predispose to the development of multiple colorectal adenomas and carcinoma, but without the florid phenotype of classical FAP, and possibly with importance for colorectal cancer risk in the general population. PMID:9724771

  6. Functional characterization of Anaphase Promoting Complex/Cyclosome (APC/C) E3 ubiquitin ligases in tumorigenesis.

    PubMed

    Zhang, Jinfang; Wan, Lixin; Dai, Xiangpeng; Sun, Yi; Wei, Wenyi

    2014-04-01

    The Anaphase Promoting Complex/Cyclosome (APC/C) is a multi-subunit E3 ubiquitin ligase that primarily governs cell cycle progression. APC/C is composed of at least 14 core subunits and recruits its substrates for ubiquitination via one of the two adaptor proteins, Cdc20 or Cdh1, in M or M/early G1 phase, respectively. Furthermore, recent studies have shed light on crucial functions for APC/C in maintaining genomic integrity, neuronal differentiation, cellular metabolism and tumorigenesis. To gain better insight into the in vivo physiological functions of APC/C in regulating various cellular processes, particularly development and tumorigenesis, a number of mouse models of APC/C core subunits, coactivators or inhibitors have been established and characterized. However, due to their essential role in cell cycle regulation, most of the germline knockout mice targeting the APC/C pathway are embryonic lethal, indicating the need for generating conditional knockout mouse models to assess the role in tumorigenesis for each APC/C signaling component in specific tissues. In this review, we will first provide a brief introduction of the ubiquitin-proteasome system (UPS) and the biochemical activities and cellular functions of the APC/C E3 ligase. We will then focus primarily on characterizing genetic mouse models used to understand the physiological roles of each APC/C signaling component in embryogenesis, cell proliferation, development and carcinogenesis. Finally, we discuss future research directions to further elucidate the physiological contributions of APC/C components during tumorigenesis and validate their potentials as a novel class of anti-cancer targets. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Germline Mutations in Predisposition Genes in Pediatric Cancer

    PubMed Central

    Edmonson, Michael N.; Gruber, Tanja A.; Easton, John; Hedges, Dale; Ma, Xiaotu; Zhou, Xin; Yergeau, Donald A.; Wilkinson, Mark R.; Vadodaria, Bhavin; Chen, Xiang; McGee, Rose B.; Hines-Dowell, Stacy; Nuccio, Regina; Quinn, Emily; Shurtleff, Sheila A.; Rusch, Michael; Patel, Aman; Becksfort, Jared B.; Wang, Shuoguo; Weaver, Meaghann S.; Ding, Li; Mardis, Elaine R.; Wilson, Richard K.; Gajjar, Amar; Ellison, David W.; Pappo, Alberto S.; Pui, Ching-Hon; Downing, James R.

    2016-01-01

    BACKGROUND The prevalence and spectrum of predisposing mutations among children and adolescents with cancer are largely unknown. Knowledge of such mutations may improve the understanding of tumorigenesis, direct patient care, and enable genetic counseling of patients and families. METHODS In 1120 patients younger than 20 years of age, we sequenced the whole genomes (in 595 patients), whole exomes (in 456), or both (in 69). We analyzed the DNA sequences of 565 genes, including 60 that have been associated with autosomal dominant cancer-predisposition syndromes, for the presence of germline mutations. The pathogenicity of the mutations was determined by a panel of medical experts with the use of cancer-specific and locus-specific genetic databases, the medical literature, computational predictions, and second hits identified in the tumor genome. The same approach was used to analyze data from 966 persons who did not have known cancer in the 1000 Genomes Project, and a similar approach was used to analyze data from an autism study (from 515 persons with autism and 208 persons without autism). RESULTS Mutations that were deemed to be pathogenic or probably pathogenic were identified in 95 patients with cancer (8.5%), as compared with 1.1% of the persons in the 1000 Genomes Project and 0.6% of the participants in the autism study. The most commonly mutated genes in the affected patients were TP53 (in 50 patients), APC (in 6), BRCA2 (in 6), NF1 (in 4), PMS2 (in 4), RB1 (in 3), and RUNX1 (in 3). A total of 18 additional patients had protein-truncating mutations in tumor-suppressor genes. Of the 58 patients with a predisposing mutation and available information on family history, 23 (40%) had a family history of cancer. CONCLUSIONS Germline mutations in cancer-predisposing genes were identified in 8.5% of the children and adolescents with cancer. Family history did not predict the presence of an underlying predisposition syndrome in most patients. (Funded by the American

  8. Extensive metabolic disorders are present in APC(min) tumorigenesis mice.

    PubMed

    Liu, Zhenzhen; Xiao, Yi; Zhou, Zhengxiang; Mao, Xiaoxiao; Cai, Jinxing; Xiong, Lu; Liao, Chaonan; Huang, Fulian; Liu, Zehao; Ali Sheikh, Md Sayed; Plutzky, Jorge; Huang, He; Yang, Tianlun; Duan, Qiong

    2016-05-15

    Wnt signaling plays essential role in mesenchymal stem cell (MSC) differentiation. Activation of Wnt signaling suppresses adipogenesis, but promotes osteogenesis in MSC. Adenomatous polyposis coli (APC) is a negative regulator of β-catenin and Wnt signaling activity. The mutation of APC gene leads to the activation of Wnt signaling and is responsible for tumorigenesis in APC(min) mouse; however, very few studies focused on its metabolic abnormalities. The present study reports a widespread metabolic disorder phenotype in APC(min) mice. The old APC(min) mice have decreased body weight and impaired adipogenesis, but severe hyperlipidemia, which mimic the phenotypes of Familial Adenomatous Polyposis (FAP), an inherited disease also caused by APC gene mutation in human. We found that the expression of lipid metabolism and free fat acids (FA) use genes in the white adipose tissue (WAT) of the APC(min) mice is much lower than those of control. The changed gene expression pattern may lead to the disability of circulatory lipid transportation and storage at WAT. Moreover, the APC(min) mice could not maintain the core body temperature in cold condition. PET-CT determination revealed that the BAT of APC(min) mice has significantly impaired ability to take up (18)FDG from the blood. Morphological studies identified that the brown adipocytes of APC(min) mice were filled with lipid droplets but fewer mitochondria. These results matched with the findings of impaired BAT function in APC(min) mice. Collectively, our study explores a new mechanism that explains abnormal metabolism in APC(min) mice and provides insights into studying the metabolic disorders of FAP patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. A conserved germline multipotency program

    PubMed Central

    Juliano, Celina E.; Swartz, S. Zachary; Wessel, Gary M.

    2010-01-01

    The germline of multicellular animals is segregated from somatic tissues, which is an essential developmental process for the next generation. Although certain ecdysozoans and chordates segregate their germline during embryogenesis, animals from other taxa segregate their germline after embryogenesis from multipotent progenitor cells. An overlapping set of genes, including vasa, nanos and piwi, operate in both multipotent precursors and in the germline. As we propose here, this conservation implies the existence of an underlying germline multipotency program in these cell types that has a previously underappreciated and conserved function in maintaining multipotency. PMID:21098563

  10. APC15 mediates CDC20 auto-ubiquitylation by APC/CMCC and MCC disassembly

    PubMed Central

    Uzunova, Kristina; Dye, Billy T.; Schutz, Hannelore; Ladurner, Rene; Petzold, Georg; Toyoda, Yusuke; Jarvis, Marc A.; Brown, Nicholas G.; Poser, Ina; Novatchkova, Maria; Mechtler, Karl; Hyman, Anthony A.; Stark, Holger; Schulman, Brenda A.; Peters, Jan-Michael

    2012-01-01

    The anaphase-promoting complex/cyclosome bound to CDC20 (APC/CCDC20) initiates anaphase by ubiquitylating B-type cyclins and securin. During chromosome bi-orientation, CDC20 assembles with MAD2, BUBR1 and BUB3 into a mitotic checkpoint complex (MCC) which inhibits substrate recruitment to the APC/C. APC/C activation depends on MCC disassembly, which has been proposed to require CDC20 auto-ubiquitylation. Here we characterized APC15, a human APC/C subunit related to yeast Mnd2. APC15 is located near APC/C’s MCC binding site, is required for APC/CMCC-dependent CDC20 auto-ubiquitylation and degradation, and for timely anaphase initiation, but is dispensable for substrate ubiquitylation by APC/CCDC20 and APC/CCDH1. Our results support the view that MCC is continuously assembled and disassembled to enable rapid activation of APC/CCDC20 and that CDC20 auto-ubiquitylation promotes MCC disassembly. We propose that APC15 and Mnd2 negatively regulate APC/C coactivators, and report the first generation of recombinant human APC/C. PMID:23007861

  11. APC — EDRN Public Portal

    Cancer.gov

    The APC gene encodes a tumor suppressor protein that acts as an antagonist of the Wnt signaling pathway. It is also involved in other processes including cell migration and adhesion, transcriptional activation, and apoptosis. Defects in this gene cause familial adenomatous polyposis (FAP), an autosomal dominant pre-malignant disease that usually progresses to malignancy. Disease-associated mutations tend to be clustered in a small region designated the mutation cluster region (MCR) and result in a truncated protein product. Promoter hypermethylation is an alternative pathway for gene silencing in neoplastic cells and a promising cancer detection marker. Methylation levels of GSTP1, APC, and RASSF1A are associated with advanced grade and stage in prostate tumors. Quantitative methylation-specific PCR (QMSP) might augment the pathologic indicators currently used to predict prostate tumor aggressiveness.

  12. Three novel mutations of APC gene in Chinese patients with familial adenomatous polyposis.

    PubMed

    Liu, Qi; Li, Xiaoxia; Li, Sen; Qu, Shengqiang; Wang, Yu; Tang, Qingzhu; Ma, Hongwei; Luo, Yang

    2016-08-01

    Familial adenomatous polyposis (FAP) is an autosomal dominant disorder characterized by the development of hundreds to thousands of colonic adenomas and an increased risk of colorectal cancer. Adenomatous polyposis coli (APC), encoding a large multidomain protein involved in antagonizing the Wnt signaling pathway, has been identified as the main causative gene responsible for FAP. In this study, we identified three novel mutations as well as two recurrent mutations in the APC in five Chinese FAP families by sequencing. Immunohistochemical analysis revealed that among these mutations, a nonsense mutation (c.2510C>G) and two small deletions (c.2016_2047del, c.3180_3184del) led to the truncation of the APC protein and the cytoplasmic and nuclear accumulation of β-catenin in the colorectal samples from affected individuals, respectively. Our study expands the database on mutations of APC and provides evidence to understand the function of APC in FAP.

  13. High performance APCS conceptual design and evaluation scoping study

    SciTech Connect

    Soelberg, N.; Liekhus, K.; Chambers, A.; Anderson, G.

    1998-02-01

    This Air Pollution Control System (APCS) Conceptual Design and Evaluation study was conducted to evaluate a high-performance (APC) system for minimizing air emissions from mixed waste thermal treatment systems. Seven variations of high-performance APCS designs were conceptualized using several design objectives. One of the system designs was selected for detailed process simulation using ASPEN PLUS to determine material and energy balances and evaluate performance. Installed system capital costs were also estimated. Sensitivity studies were conducted to evaluate the incremental cost and benefit of added carbon adsorber beds for mercury control, specific catalytic reduction for NO{sub x} control, and offgas retention tanks for holding the offgas until sample analysis is conducted to verify that the offgas meets emission limits. Results show that the high-performance dry-wet APCS can easily meet all expected emission limits except for possibly mercury. The capability to achieve high levels of mercury control (potentially necessary for thermally treating some DOE mixed streams) could not be validated using current performance data for mercury control technologies. The engineering approach and ASPEN PLUS modeling tool developed and used in this study identified APC equipment and system performance, size, cost, and other issues that are not yet resolved. These issues need to be addressed in feasibility studies and conceptual designs for new facilities or for determining how to modify existing facilities to meet expected emission limits. The ASPEN PLUS process simulation with current and refined input assumptions and calculations can be used to provide system performance information for decision-making, identifying best options, estimating costs, reducing the potential for emission violations, providing information needed for waste flow analysis, incorporating new APCS technologies in existing designs, or performing facility design and permitting activities.

  14. lemmingA encodes the Apc11 subunit of the APC/C in Drosophila melanogaster that forms a ternary complex with the E2-C type ubiquitin conjugating enzyme, Vihar and Morula/Apc2

    PubMed Central

    2012-01-01

    Background Ubiquitin-dependent protein degradation is a critical step in key cell cycle events, such as metaphase-anaphase transition and mitotic exit. The anaphase promoting complex/cyclosome (APC/C) plays a pivotal role in these transitions by recognizing and marking regulatory proteins for proteasomal degradation. Its overall structure and function has been elucidated mostly in yeasts and mammalian cell lines. The APC/C is, however, a multisubunit assembly with at least 13 subunits and their function and interaction within the complex is still relatively uncharacterized, particularly in metazoan systems. Here, lemming (lmg) mutants were used to study the APC/C subunit, Apc11, and its interaction partners in Drosophila melanogaster. Results The lmg gene was initially identified through a pharate adult lethal P element insertion mutation expressing developmental abnormalities and widespread apoptosis in larval imaginal discs and pupal abdominal histoblasts. Larval neuroblasts were observed to arrest mitosis in a metaphase-like state with highly condensed, scattered chromosomes and frequent polyploidy. These neuroblasts contain high levels of both cyclin A and cyclin B. The lmg gene was cloned by virtue of the lmg03424 P element insertion which is located in the 5' untranslated region. The lemming locus is transcribed to give a 2.0 kb mRNA that contains two ORFs, lmgA and lmgB. The lmgA ORF codes for a putative protein with more than 80% sequence homology to the APC11 subunit of the human APC/C. The 85 amino acid protein also contains a RING-finger motif characteristic of known APC11 subunits. The lmgA ORF alone was sufficient to rescue the lethal and mitotic phenotypes of the lmg138 null allele and to complement the temperature sensitive lethal phenotype of the APC11-myc9 budding yeast mutant. The LmgA protein interacts with Mr/Apc2, and they together form a binding site for Vihar, the E2-C type ubiquitin conjugating enzyme. Despite being conserved among

  15. APC binds the Miro/Milton motor complex to stimulate transport of mitochondria to the plasma membrane.

    PubMed

    Mills, Kate M; Brocardo, Mariana G; Henderson, Beric R

    2016-02-01

    Mutations in adenomatous polyposis coli (APC) disrupt regulation of Wnt signaling, mitosis, and the cytoskeleton. We describe a new role for APC in the transport of mitochondria. Silencing of wild-type APC by small interfering RNA caused mitochondria to redistribute from the cell periphery to the perinuclear region. We identified novel APC interactions with the mitochondrial kinesin-motor complex Miro/Milton that were mediated by the APC C-terminus. Truncating mutations in APC abolished its ability to bind Miro/Milton and reduced formation of the Miro/Milton complex, correlating with disrupted mitochondrial distribution in colorectal cancer cells that could be recovered by reconstitution of wild-type APC. Using proximity ligation assays, we identified endogenous APC-Miro/Milton complexes at mitochondria, and live-cell imaging showed that loss of APC slowed the frequency of anterograde mitochondrial transport to the membrane. We propose that APC helps drive mitochondria to the membrane to supply energy for cellular processes such as directed cell migration, a process disrupted by cancer mutations.

  16. Human Germline Genome Editing.

    PubMed

    Ormond, Kelly E; Mortlock, Douglas P; Scholes, Derek T; Bombard, Yvonne; Brody, Lawrence C; Faucett, W Andrew; Garrison, Nanibaa' A; Hercher, Laura; Isasi, Rosario; Middleton, Anna; Musunuru, Kiran; Shriner, Daniel; Virani, Alice; Young, Caroline E

    2017-08-03

    With CRISPR/Cas9 and other genome-editing technologies, successful somatic and germline genome editing are becoming feasible. To respond, an American Society of Human Genetics (ASHG) workgroup developed this position statement, which was approved by the ASHG Board in March 2017. The workgroup included representatives from the UK Association of Genetic Nurses and Counsellors, Canadian Association of Genetic Counsellors, International Genetic Epidemiology Society, and US National Society of Genetic Counselors. These groups, as well as the American Society for Reproductive Medicine, Asia Pacific Society of Human Genetics, British Society for Genetic Medicine, Human Genetics Society of Australasia, Professional Society of Genetic Counselors in Asia, and Southern African Society for Human Genetics, endorsed the final statement. The statement includes the following positions. (1) At this time, given the nature and number of unanswered scientific, ethical, and policy questions, it is inappropriate to perform germline gene editing that culminates in human pregnancy. (2) Currently, there is no reason to prohibit in vitro germline genome editing on human embryos and gametes, with appropriate oversight and consent from donors, to facilitate research on the possible future clinical applications of gene editing. There should be no prohibition on making public funds available to support this research. (3) Future clinical application of human germline genome editing should not proceed unless, at a minimum, there is (a) a compelling medical rationale, (b) an evidence base that supports its clinical use, (c) an ethical justification, and (d) a transparent public process to solicit and incorporate stakeholder input. Copyright © 2017 American Society of Human Genetics. All rights reserved.

  17. Screening for germline BRCA1, BRCA2, TP53 and CHEK2 mutations in families at-risk for hereditary breast cancer identified in a population-based study from Southern Brazil

    PubMed Central

    Palmero, Edenir Inêz; Alemar, Bárbara; Schüler-Faccini, Lavínia; Hainaut, Pierre; Moreira-Filho, Carlos Alberto; Ewald, Ingrid Petroni; dos Santos, Patricia Koehler; Ribeiro, Patricia Lisbôa Izetti; de Oliveira, Cristina Brinkmann; Kelm, Florence Le Calvez; Tavtigian, Sean; Cossio, Silvia Liliana; Giugliani, Roberto; Caleffi, Maira; Ashton-Prolla, Patricia

    2016-01-01

    Abstract In Brazil, breast cancer is a public health care problem due to its high incidence and mortality rates. In this study, we investigated the prevalence of hereditary breast cancer syndromes (HBCS) in a population-based cohort in Brazils southernmost capital, Porto Alegre. All participants answered a questionnaire about family history (FH) of breast, ovarian and colorectal cancer and those with a positive FH were invited for genetic cancer risk assessment (GCRA). If pedigree analysis was suggestive of HBCS, genetic testing of the BRCA1, BRCA2, TP53, and CHEK2 genes was offered. Of 902 women submitted to GCRA, 214 had pedigrees suggestive of HBCS. Fifty of them underwent genetic testing: 18 and 40 for BRCA1/BRCA2 and TP53 mutation screening, respectively, and 7 for CHEK2 1100delC testing. A deleterious BRCA2 mutation was identified in one of the HBOC probands and the CHEK2 1100delC mutation occurred in one of the HBCC families. No deleterious germline alterations were identified in BRCA1 or TP53. Although strict inclusion criteria and a comprehensive testing approach were used, the suspected genetic risk in these families remains unexplained. Further studies in a larger cohort are necessary to better understand the genetic component of hereditary breast cancer in Southern Brazil. PMID:27223485

  18. Prevalence of Germline Mutations in Cancer Predisposition Genes in Patients with Pancreatic Cancer

    PubMed Central

    Grant, Robert C.; Selander, Iris; Connor, Ashton A.; Selvarajah, Shamini; Borgida, Ayelet; Briollais, Laurent; Petersen, Gloria M.; Lerner-Ellis, Jordan; Holter, Spring; Gallinger, Steven

    2015-01-01

    Background & Aims We investigated the prevalence of germline mutations in APC, ATM, BRCA1, BRCA2, CDKN2A, MLH1, MSH2, MSH6, PALB2, PMS2, PRSS1, STK11, and TP53 in patients with pancreatic cancer. Methods The Ontario Pancreas Cancer Study enrolls consenting participants with pancreatic cancer from a province-wide electronic pathology database; 708 probands were enrolled from April 2003 through August 2012. To improve precision of BRCA2 prevalence estimates, 290 probands were randomly selected from 3 strata, based on family history of breast and/or ovarian cancer, pancreatic cancer, or neither. Germline DNA was analyzed by next-generation sequencing using a custom multiple-gene panel. Mutation prevalence estimates were calculated from the sample for the entire cohort. Results Eleven pathogenic mutations were identified: 3 in ATM, 1 in BRCA1, 2 in BRCA2, 1 in MLH1, 2 in MSH2, 1 in MSH6, and 1 in TP53. The prevalence of mutations in all 13 genes was 3.8% (95% confidence interval, 2.1%–5.6%). Carrier status was significantly associated with breast cancer in the proband or first-degree relative (P<.01), and colorectal cancer in the proband or first-degree relative (P<.01), but not family history of pancreatic cancer, age of diagnosis, or stage at diagnosis. Of patients with a personal or family history of breast and colorectal cancer, 10.7% (4.4%–17.0%) and 11.1% (3.0%–19.1%) carried pathogenic mutations, respectively. Conclusions A small but clinically important proportion of pancreatic cancer is associated with mutations in known predisposition genes. The heterogeneity of mutations identified in this study demonstrates the value of using a multiple-gene panel in pancreatic cancer. PMID:25479140

  19. Parallel antibody germline gene and haplotype analyses support the validity of immunoglobulin germline gene inference and discovery.

    PubMed

    Kirik, Ufuk; Greiff, Lennart; Levander, Fredrik; Ohlin, Mats

    2017-04-04

    Analysis of antibody repertoire development and specific antibody responses important for e.g. autoimmune conditions, allergy, and protection against disease is supported by high throughput sequencing and associated bioinformatics pipelines that describe the diversity of the encoded antibody variable domains. Proper assignment of sequences to germline genes are important for many such processes, for instance in the analysis of somatic hypermutation. Germline gene inference from antibody-encoding transcriptomes, by using tools such as TIgGER or IgDiscover, has a potential to enhance the quality of such analyses. These tools may also be used to identify germline genes not previously known. In this study, we exploited such software for germline gene inference and define aspects of analysis settings and pre-existing knowledge of germline genes that affect the outcome of gene inference. Furthermore, we demonstrate the capacity of IGHJ and IGHD haplotype inference, whenever subjects are heterozygous with respect to such genes, to lend support to IGHV gene inference in general, and to the identification of novel alleles presently not recognized by germline gene reference directories. We propose that such haplotype analysis shall, whenever possible, be used in future best practice to support the outcome of germline gene inference. IGHJ-directed haplotype inference was also used to identify haplotypes not expressing some IGHV germline genes. In particular, we identified a haplotype that did not express several major germline genes such as IGHV1-8, IGHV3-9, IGHV3-15, IGHV1-18, IGHV3-21, and IGHV3-23. We envisage that haplotype analysis will provide an efficient approach to identify subjects for further studies of the link between the available immunoglobulin repertoire and outcomes of immune responses.

  20. Inhibition of APC-mediated proteolysis by the meiosis-specific protein kinase Ime2

    PubMed Central

    Bolte, Melanie; Steigemann, Patrick; Braus, Gerhard H.; Irniger, Stefan

    2002-01-01

    Proteolysis triggered by the anaphase-promoting complex (APC) is needed for sister chromatid separation and the exit from mitosis. APC is a ubiquitin ligase whose activity is tightly controlled during the cell cycle. To identify factors involved in the regulation of APC-mediated proteolysis, a Saccharomyces cerevisiae GAL-cDNA library was screened for genes whose overexpression prevented degradation of an APC target protein, the mitotic cyclin Clb2. Genes encoding G1, S, and mitotic cyclins were identified, consistent with previous data showing that the cyclin-dependent kinase Cdk1 associated with different cyclins is a key factor for inhibiting APCCdh1 activity from late-G1 phase until mitosis. In addition, the meiosis-specific protein kinase Ime2 was identified as a negative regulator of APC-mediated proteolysis. Ectopic expression of IME2 in G1 arrested cells inhibited the degradation of mitotic cyclins and of other APC substrates. IME2 expression resulted in the phosphorylation of Cdh1 in G1 cells, indicating that Ime2 and Cdk1 regulate APCCdh1 in a similar manner. The expression of IME2 in cycling cells inhibited bud formation and caused cells to arrest in mitosis. We show further that Ime2 itself is an unstable protein whose proteolysis occurs independently of the APC and SCF (Skp1/Cdc53/F-box) ubiquitin ligases. Our findings suggest that Ime2 represents an unstable, meiosis-specific regulator of APCCdh1. PMID:11917129

  1. MYH biallelic mutation can inactivate the two genetic pathways of colorectal cancer by APC or MLH1 transversions.

    PubMed

    Lefevre, Jérémie H; Colas, Chrystelle; Coulet, Florence; Bonilla, Carolina; Mourra, Najat; Flejou, Jean-Francois; Tiret, Emmanuel; Bodmer, Walter; Soubrier, Florent; Parc, Yann

    2010-12-01

    MYH associated polyposis is a hereditary syndrome responsible for early colorectal cancer with a distinct genetic pathway from the Familial Adenomatous Polyposis or the Hereditary Non Polyposis Colorectal Cancer syndrome. We have studied a family with three members bearing a biallelic mutation in MYH at c.1185_1186dup. One patient who developed colon cancer had loss of expression of MLH1 on tumoral tissue and microsatellite instability (MSI) phenotype. Analysis of MLH1 based on his blood sample revealed no germline mutation or large genomic deletion. No methylation of the promoter was identified in tumoral DNA. No transversion mutations were identified in APC or KRAS in tumor DNA of this patient. Loss of expression of MLH1 was due to a transversion in intron 7 at position +5 (c.588 + 5G > T) leading to a complete deletion of exon 7 at the RNA level. This observation demonstrates that MLH1 can be a target of MYH transversions leading to MSI phenotype.

  2. Immunohistochemical markers of the hypoxic response can identify malignancy in phaeochromocytomas and paragangliomas and optimize the detection of tumours with VHL germline mutations

    PubMed Central

    Pinato, D J; Ramachandran, R; Toussi, S T K; Vergine, M; Ngo, N; Sharma, R; Lloyd, T; Meeran, K; Palazzo, F; Martin, N; Khoo, B; Dina, R; Tan, T M

    2013-01-01

    Background: There are no reliable markers of malignancy in phaeochromocytomas (PCC) and paragangliomas (PGL). We investigated the relevance of the mammalian target of rapamycin (mTOR)/AKT and hypoxic pathways as novel immunohistochemical markers of malignancy. Methods: Tissue microarray blocks were constructed with a total of 100 tumours (10 metastatic) and 20 normal adrenomedullary samples. Sections were immunostained for hypoxia-inducible factor 1α (Hif-1α), vascular endothelial growth factor A (VEGF-A), mTOR, carbonic anhydrase IX (CaIX) and AKT. The predictive performance of these markers was studied using univariate, multivariate and receiver operating characteristic analyses. Results: In all, 100 consecutive patients, 64% PCC, 29% familial with a median tumour size of 4.7 cm (range 1–14) were included. Univariate analyses showed Hif-1α overexpression, tumour necrosis, size >5 cm, capsular and vascular invasion to be predictors of metastasis. In multivariate analysis, Hif-1α, necrosis and vascular invasion remained as independent predictors of metastasis. Hif-1α was the most discriminatory biomarker for the presence of metastatic diffusion. Strong membranous CaIX expression was seen in von Hippel–Lindau (VHL) PCC as opposed to other subtypes. Conclusion: Lack of vascular invasion, tumour necrosis and low Hif-1α expression identify tumours with lower risk of malignancy. We propose membranous CaIX expression as a potential marker for VHL disease in patients presenting with PCC. PMID:23257898

  3. Metabolomics of Apc Min/+ mice genetically susceptible to intestinal cancer

    PubMed Central

    2014-01-01

    Background To determine how diets high in saturated fat could increase polyp formation in the mouse model of intestinal neoplasia, Apc Min/+ , we conducted large-scale metabolome analysis and association study of colon and small intestine polyp formation from plasma and liver samples of Apc Min/+ vs. wild-type littermates, kept on low vs. high-fat diet. Label-free mass spectrometry was used to quantify untargeted plasma and acyl-CoA liver compounds, respectively. Differences in contrasts of interest were analyzed statistically by unsupervised and supervised modeling approaches, namely Principal Component Analysis and Linear Model of analysis of variance. Correlation between plasma metabolite concentrations and polyp numbers was analyzed with a zero-inflated Generalized Linear Model. Results Plasma metabolome in parallel to promotion of tumor development comprises a clearly distinct profile in Apc Min/+ mice vs. wild type littermates, which is further altered by high-fat diet. Further, functional metabolomics pathway and network analyses in Apc Min/+ mice on high-fat diet revealed associations between polyp formation and plasma metabolic compounds including those involved in amino-acids metabolism as well as nicotinamide and hippuric acid metabolic pathways. Finally, we also show changes in liver acyl-CoA profiles, which may result from a combination of Apc Min/+ -mediated tumor progression and high fat diet. The biological significance of these findings is discussed in the context of intestinal cancer progression. Conclusions These studies show that high-throughput metabolomics combined with appropriate statistical modeling and large scale functional approaches can be used to monitor and infer changes and interactions in the metabolome and genome of the host under controlled experimental conditions. Further these studies demonstrate the impact of diet on metabolic pathways and its relation to intestinal cancer progression. Based on our results, metabolic signatures

  4. Complete deletion of Apc results in severe polyposis in mice.

    PubMed

    Cheung, A F; Carter, A M; Kostova, K K; Woodruff, J F; Crowley, D; Bronson, R T; Haigis, K M; Jacks, T

    2010-03-25

    The adenomatous polyposis coli (APC) gene product is mutated in the vast majority of human colorectal cancers. APC negatively regulates the WNT pathway by aiding in the degradation of beta-catenin, which is the transcription factor activated downstream of WNT signaling. APC mutations result in beta-catenin stabilization and constitutive WNT pathway activation, leading to aberrant cellular proliferation. APC mutations associated with colorectal cancer commonly fall in a region of the gene termed the mutation cluster region and result in expression of an N-terminal fragment of the APC protein. Biochemical and molecular studies have revealed localization of APC/Apc to different sub-cellular compartments and various proteins outside of the WNT pathway that associate with truncated APC/Apc. These observations and genotype-phenotype correlations have led to the suggestion that truncated APC bears neomorphic and/or dominant-negative function that support tumor development. To analyze this possibility, we have generated a novel allele of Apc in the mouse that yields complete loss of Apc protein. Our studies reveal that whole-gene deletion of Apc results in more rapid tumor development than the APC multiple intestinal neoplasia (Apc(Min)) truncation. Furthermore, we found that adenomas bearing truncated Apc had increased beta-catenin activity when compared with tumors lacking Apc protein, which could lead to context-dependent inhibition of tumorigenesis.

  5. Preclinical Safety and Pharmacokinetic Profile of 3K3A-APC, a Novel, Modified Activated Protein C for Ischemic Stroke

    PubMed Central

    Williams, Patricia D.; Zlokovic, Berislav V.; Griffin, John H.; Pryor, Kent E.; Davis, Thomas P.

    2012-01-01

    Activated protein C (APC), a protease with anticoagulant and cytoprotective activities, protects neurons and cerebrovascular endothelium from ischemic injury. A recombinant APC, drotrecogin alfa (activated) (DrotAA) (Xigris®), was approved by the Food and Drug Administration for the treatment of sepsis; however, serious bleeding was a dose-limiting side effect. A modified APC, containing 405 amino acid residues, 3K3A-APC, was designed to possess significantly reduced anticoagulant activity (< 10 %) while maintaining full cytoprotective properties. The preclinical safety assessment of 3K3A-APC was conducted to support initiation of ischemic stroke clinical trials. The safety and toxicokinetics of 3K3A-APC were studied in CD-1 mice and cynomolgus monkeys. Multiple-dose (14-day), intravenous GLP toxicology assessed toxicity, histopathology, immunogenicity, and toxicokinetics. Dose-related increases in plasma total 3K3A-APC were observed in mice and monkeys with no evidence of accumulation over 14 days. The elimination T1/2 in monkeys was 1 hour. 3K3A-APC was well tolerated in mice and monkeys, and no signs of 3K3A-APC toxicity were identified in mice or monkeys at any time. Additionally, wild-type APC (DrotAA) was studied to obtain comparative anticoagulant data using clotting assays. Anticoagulant activity of 3K3A-APC was observed in monkeys at doses of 1 and 5 mg/kg/day. In contrast, DrotAA showed prolongation of clotting assays in monkeys at doses 1/10th of those showing effects with 3K3A-APC. Based upon the anticoagulant profiles, the risk for APC-induced bleeding in clinical trials of 3K3A-APC is greatly reduced relative to wild type APC which makes this new drug a feasible therapy for ischemic stroke patients. PMID:22632606

  6. Adenomatous polyposis coli (APC) regulates miR17-92 cluster through β-catenin pathway in colorectal cancer.

    PubMed

    Li, Y; Lauriola, M; Kim, D; Francesconi, M; D'Uva, G; Shibata, D; Malafa, M P; Yeatman, T J; Coppola, D; Solmi, R; Cheng, J Q

    2016-09-01

    Adenomatous polyposis coli (APC) mutation is the most common genetic change in sporadic colorectal cancer (CRC). Although deregulations of miRNAs have been frequently reported in this malignancy, APC-regulated miRNAs have not been extensively documented. Here, by using an APC-inducible cell line and array analysis, we identified a total of 26 deregulated miRNAs. Among them, members of miR-17-92 cluster were dramatically inhibited by APC and induced by enforced expression of β-catenin. Furthermore, we demonstrate that activated β-catenin resulted from APC loss binds to and activates the miR-17-92 promoter. Notably, enforced expression of miR-19a overrides APC tumor suppressor activity, and knockdown of miR-19a in cancer cells with compromised APC function reduced their aggressive features in vitro. Finally, we observed that expression of miR-19a significantly correlates with β-catenin levels in colorectal cancer specimens, and it is associated to the aggressive stage of tumor progression. Thus, our study reveals that miR-17-92 cluster is directly regulated by APC/β-catenin pathway and could be a potential therapeutic target in colon cancers with aberrant APC/β-catenin signaling.

  7. Adenomatous Polyposis Coli (APC) regulates miR17-92 cluster through β-catenin pathway in colorectal cancer

    PubMed Central

    Francesconi, Mirko; D'Uva, Gabriele; Shibata, Dave; Malafa, Mokenge P.; Yeatman, Timothy J.

    2016-01-01

    APC mutation is the most common genetic changes in sporadic colorectal cancer (CRC). Despite deregulations of miRNAs have been frequently reported in this malignancy, APC regulated miRNAs have not been extensively documented. Here, by employing an APC inducible cell line and array analysis, we identified a total of 26 deregulated miRNAs. Among them members of miR-17-92 cluster were dramatically inhibited by APC and induced by enforced expression of β-catenin. Furthermore, we demonstrate that activated β-catenin resulted from APC loss binds to and activates the miR-17-92 promoter. Notably, enforced expression of miR-19a overrides APC tumour suppressor activity and knockdown of miR-19a in cancer cells with compromised APC function reduced their aggressive features in vitro. Finally, we observed that expression of miR-19a significantly correlates with β-catenin levels in colorectal cancer specimens, and it is associated to the aggressive stage of tumour progression. Thus our study reveals that miR-17-92 cluster is directly regulated by APC/β-catenin pathway and could be a potential therapeutic target in colon cancers with aberrant APC/β-catenin signaling. PMID:26804172

  8. Disease severity and genetic pathways in attenuated familial adenomatous polyposis vary greatly but depend on the site of the germline mutation

    PubMed Central

    Sieber, O M; Segditsas, S; Knudsen, A L; Zhang, J; Luz, J; Rowan, A J; Spain, S L; Thirlwell, C; Howarth, K M; Jaeger, E E M; Robinson, J; Volikos, E; Silver, A; Kelly, G; Aretz, S; Frayling, I; Hutter, P; Dunlop, M; Guenther, T; Neale, K; Phillips, R; Heinimann, K; Tomlinson, I P M

    2006-01-01

    Background Attenuated familial adenomatous polyposis (AFAP) is associated with germline mutations in the 5′, 3′, and exon 9 of the adenomatous polyposis coli (APC) gene. These mutations probably encode a limited amount of functional APC protein. Methods and results We found that colonic polyp number varied greatly among AFAP patients but members of the same family tended to have more similar disease severity. 5′ Mutants generally had more polyps than other patients. We analysed somatic APC mutations/loss of heterozygosity (LOH) in 235 tumours from 35 patients (16 families) with a variety of AFAP associated germline mutations. In common with two previous studies of individual kindreds, we found biallelic changes (“third hits”) in some polyps. We found that the “third hit” probably initiated tumorigenesis. Somatic mutation spectra were similar in 5′ and 3′ mutant patients, often resembling classical FAP. In exon 9 mutants, in contrast, “third hits” were more common. Most “third hits” left three 20 amino acid repeats (20AARs) on the germline mutant APC allele, with LOH (or proximal somatic mutation) of the wild‐type allele; but some polyps had loss of the germline mutant with mutation leaving one 20AAR on the wild‐type allele. Conclusions We propose that mutations, such as nt4661insA, that leave three 20AARs are preferentially selected in cis with some AFAP mutations because the residual protein function is near optimal for tumorigenesis. Not all AFAP polyps appear to need “three hits” however. AFAP is phenotypically and genetically heterogeneous. In addition to effects of different germline mutations, modifier genes may be acting on the AFAP phenotype, perhaps influencing the quantity of functional protein produced by the germline mutant allele. PMID:16461775

  9. Targeting the DNA replication checkpoint by pharmacologic inhibition of Chk1 kinase: a strategy to sensitize APC mutant colon cancer cells to 5-fluorouracil chemotherapy.

    PubMed

    Martino-Echarri, Estefania; Henderson, Beric R; Brocardo, Mariana G

    2014-10-30

    5-fluorouracil (5-FU) is the first line component used in colorectal cancer (CRC) therapy however even in combination with other chemotherapeutic drugs recurrence is common. Mutations of the adenomatous polyposis coli (APC) gene are considered as the initiating step of transformation in familial and sporadic CRCs. We have previously shown that APC regulates the cellular response to DNA replication stress and recently hypothesized that APC mutations might therefore influence 5-FU resistance. To test this, we compared CRC cell lines and show that those expressing truncated APC exhibit a limited response to 5-FU and arrest in G1/S-phase without undergoing lethal damage, unlike cells expressing wild-type APC. In SW480 APC-mutant CRC cells, 5-FU-dependent apoptosis was restored after transient expression of full length APC, indicating a direct link between APC and drug response. Furthermore, we could increase sensitivity of APC truncated cells to 5-FU by inactivating the Chk1 kinase using drug treatment or siRNA-mediated knockdown. Our findings identify mutant APC as a potential tumor biomarker of resistance to 5-FU, and importantly we show that APC-mutant CRC cells can be made more sensitive to 5-FU by use of Chk1 inhibitors.

  10. Apoptosis and APC in colorectal tumorigenesis.

    PubMed Central

    Morin, P J; Vogelstein, B; Kinzler, K W

    1996-01-01

    Tumors result from disruptions in the homeostatic mechanisms that regulate cell birth and cell death. In colon cancer, one of the earliest manifestation of this imbalance is the formation of polyps, caused by somatic and inherited mutations of the adenomatous polyposis coli (APC) tumor suppressor gene in both humans and mice. While the importance of APC in tumorigenesis is well documented, how it functions to prevent tumors remains a mystery. Using a novel inducible expression system, we show that expression of APC in human colorectal cancer cells containing endogenous inactive APC alleles results in a substantial diminution of cell growth. Further evaluation demonstrated that this was due to the induction of cell death through apoptosis. These results suggest that apoptosis plays a role not only in advanced tumors but also at the very earliest stages of neoplasia. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8755583

  11. APC implementation in Chandra Asri - ethylene plant

    NASA Astrophysics Data System (ADS)

    Sidiq, Mochamad; Mustofa, Ali

    2017-05-01

    Nowadays, the modern process plants are continuously improved for maximizing production, Optimization of the energy and raw material and reducing the risk. Due to many disturbances appearance between the process units, hence, the failure of one unit might have a bad effect on the overall productivity. Ethylene Plant have significant opportunities for using Advanced Process Control (APC) technologies to improve operation stability, push closer to quality or equipment limit, and improve the capability of process units to handle disturbances. APC implementation had considered a best answer for solving multivariable control problem. PT. Chandra Asri Petrochemical, Tbk (CAP) operates a large naphtha cracker complex at Cilegon, Indonesia. To optimize the plant operation and to enhance the benefit, Chandra Asri has been decided to implement Advance Process Control (APC) for ethylene plant. The APC implementation technology scopes at CAP are as follows: 1. Hot Section : Furnaces, Quench Tower 2. Cold Section : Demethanizer, Deethanizer, Acetylene Converter, Ethylene Fractionator, Depropanizer, Propylene Fractionator, Debutanizer

  12. Data sharing system for lithography APC

    NASA Astrophysics Data System (ADS)

    Kawamura, Eiichi; Teranishi, Yoshiharu; Shimabara, Masanori

    2007-03-01

    We have developed a simple and cost-effective data sharing system between fabs for lithography advanced process control (APC). Lithography APC requires process flow, inter-layer information, history information, mask information and so on. So, inter-APC data sharing system has become necessary when lots are to be processed in multiple fabs (usually two fabs). The development cost and maintenance cost also have to be taken into account. The system handles minimum information necessary to make trend prediction for the lots. Three types of data have to be shared for precise trend prediction. First one is device information of the lots, e.g., process flow of the device and inter-layer information. Second one is mask information from mask suppliers, e.g., pattern characteristics and pattern widths. Last one is history data of the lots. Device information is electronic file and easy to handle. The electronic file is common between APCs and uploaded into the database. As for mask information sharing, mask information described in common format is obtained via Wide Area Network (WAN) from mask-vender will be stored in the mask-information data server. This information is periodically transferred to one specific lithography-APC server and compiled into the database. This lithography-APC server periodically delivers the mask-information to every other lithography-APC server. Process-history data sharing system mainly consists of function of delivering process-history data. In shipping production lots to another fab, the product-related process-history data is delivered by the lithography-APC server from the shipping site. We have confirmed the function and effectiveness of data sharing systems.

  13. Germ-line gene modification and disease prevention: some medical and ethical perspectives.

    PubMed

    Wivel, N A; Walters, L

    1993-10-22

    There has been considerable debate about the ethics of human germ-line gene modification. As a result of recent advances in the micromanipulation of embryos and the laboratory development of transgenic mice, a lively discussion has begun concerning both the technical feasibility and the ethical acceptability of human germ-line modification for the prevention of serious disease. This article summarizes some of the recent research on germ-line gene modification in animal models. Certain monogenic deficiency diseases that ultimately might be candidates for correction by germ-line intervention are identified. Several of the most frequently considered ethical issues relative to human germ-line gene modification are considered in the context of professional ethics, parental responsibility, and public policy. Finally, it is suggested that there is merit in continuing the discussion about human germ-line intervention, so that this technique can be carefully compared with alternative strategies for preventing genetic disease.

  14. Germ-line and somatic DICER1 mutations in pineoblastoma

    PubMed Central

    de Kock, Leanne; Sabbaghian, Nelly; Druker, Harriet; Weber, Evan; Hamel, Nancy; Miller, Suzanne; Choong, Catherine S.; Gottardo, Nicholas G.; Kees, Ursula R.; Rednam, Surya P.; van Hest, Liselotte P.; Jongmans, Marjolijn C.; Jhangiani, Shalini; Lupski, James R.; Zacharin, Margaret; Bouron-Dal Soglio, Dorothée; Huang, Annie; Priest, John R.; Perry, Arie; Mueller, Sabine; Albrecht, Steffen; Malkin, David; Grundy, Richard G.

    2015-01-01

    Germ-line RB-1 mutations predispose to pineoblastoma (PinB), but other predisposing genetic factors are not well established. We recently identifed a germ-line DICER1 mutation in a child with a PinB. This was accompanied by loss of heterozygosity (LOH) of the wild-type allele within the tumour. We set out to establish the prevalence of DICER1 mutations in an opportunistically ascertained series of PinBs. Twenty-one PinB cases were studied: eighteen cases had not undergone previous testing for DICER1 mutations; three patients were known carriers of germ-line DICER1 mutations. The eighteen PinBs were sequenced by Sanger and/or Fluidigm-based next-generation sequencing to identify DICER1 mutations in blood gDNA and/or tumour gDNA. Testing for somatic DICER1 mutations was also conducted on one case with a known germ-line DICER1 mutation. From the eighteen PinBs, we identified four deleterious DICER1 mutations, three of which were germ line in origin, and one for which a germ line versus somatic origin could not be determined; in all four, the second allele was also inactivated leading to complete loss of DICER1 protein. No somatic DICER1 RNase IIIb mutations were identified. One PinB arising in a germ-line DICER1 mutation carrier was found to have LOH. This study suggests that germ-line DICER1 mutations make a clinically significant contribution to PinB, establishing DICER1 as an important susceptibility gene for PinB and demonstrates PinB to be a manifestation of a germ-line DICER1 mutation. The means by which the second allele is inactivated may differ from other DICER1-related tumours. PMID:25022261

  15. New Functions of APC/C Ubiquitin Ligase in the Nervous System and Its Role in Alzheimer’s Disease

    PubMed Central

    Fuchsberger, Tanja; Lloret, Ana; Viña, Jose

    2017-01-01

    The E3 ubiquitin ligase Anaphase Promoting Complex/Cyclosome (APC/C) regulates important processes in cells, such as the cell cycle, by targeting a set of substrates for degradation. In the last decade, APC/C has been related to several major functions in the nervous system, including axon guidance, synaptic plasticity, neurogenesis, and neuronal survival. Interestingly, some of the identified APC/C substrates have been related to neurodegenerative diseases. There is an accumulation of some degradation targets of APC/C in Alzheimer’s disease (AD) brains, which suggests a dysregulation of the protein complex in the disorder. Moreover, recently evidence has been provided for an inactivation of APC/C in AD. It has been shown that oligomers of the AD-related peptide, Aβ, induce degradation of the APC/C activator subunit cdh1, in vitro in neurons in culture and in vivo in the mouse hippocampus. Furthermore, in the AD mouse model APP/PS1, lower cdh1 levels were observed in pyramidal neurons in CA1 when compared to age-matched wildtype mice. In this review, we provide a complete list of APC/C substrates that are involved in the nervous system and we discuss their functions. We also summarize recent studies that show neurobiological effects in cdh1 knockout mouse models. Finally, we discuss the role of APC/C in the pathophysiology of AD. PMID:28505105

  16. The tumour suppressor gene product APC blocks cell cycle progression from G0/G1 to S phase.

    PubMed Central

    Baeg, G H; Matsumine, A; Kuroda, T; Bhattacharjee, R N; Miyashiro, I; Toyoshima, K; Akiyama, T

    1995-01-01

    The APC gene is mutated in familial adenomatous polyposis (FAP) as well as in sporadic colorectal tumours. The product of the APC gene is a 300 kDa cytoplasmic protein associated with the adherence junction protein catenin. Here we show that overexpression of APC blocks serum-induced cell cycle progression from G0/G1 to the S phase. Mutant APCs identified in FAP and/or colorectal tumours were less inhibitory and partially obstructed the activity of the normal APC. The cell-cycle blocking activity of APC was alleviated by the overexpression of cyclin E/CDK2 or cyclin D1/CDK4. Consistent with this result, kinase activity of CDK2 was significantly down-regulated in cells overexpressing APC although its synthesis remained unchanged, while CDK4 activity was barely affected. These results suggest that APC may play a role in the regulation of the cell cycle by negatively modulating the activity of cyclin-CDK complexes. Images PMID:8521819

  17. Dual control by Cdk1 phosphorylation of the budding yeast APC/C ubiquitin ligase activator Cdh1

    PubMed Central

    Höckner, Sebastian; Neumann-Arnold, Lea; Seufert, Wolfgang

    2016-01-01

    The antagonism between cyclin-dependent kinases (Cdks) and the ubiquitin ligase APC/C-Cdh1 is central to eukaryotic cell cycle control. APC/C-Cdh1 targets cyclin B and other regulatory proteins for degradation, whereas Cdks disable APC/C-Cdh1 through phosphorylation of the Cdh1 activator protein at multiple sites. Budding yeast Cdh1 carries nine Cdk phosphorylation sites in its N-terminal regulatory domain, most or all of which contribute to inhibition. However, the precise role of individual sites has remained unclear. Here, we report that the Cdk phosphorylation sites of yeast Cdh1 are organized into autonomous subgroups and act through separate mechanisms. Cdk sites 1–3 had no direct effect on the APC/C binding of Cdh1 but inactivated a bipartite nuclear localization sequence (NLS) and thereby controlled the partitioning of Cdh1 between cytoplasm and nucleus. In contrast, Cdk sites 4–9 did not influence the cell cycle–regulated localization of Cdh1 but prevented its binding to the APC/C. Cdk sites 4–9 reside near two recently identified APC/C interaction motifs in a pattern conserved with the human Cdh1 orthologue. Thus a Cdk-inhibited NLS goes along with Cdk-inhibited APC/C binding sites in yeast Cdh1 to relay the negative control by Cdk1 phosphorylation of the ubiquitin ligase APC/C-Cdh1. PMID:27226481

  18. Dual control by Cdk1 phosphorylation of the budding yeast APC/C ubiquitin ligase activator Cdh1.

    PubMed

    Höckner, Sebastian; Neumann-Arnold, Lea; Seufert, Wolfgang

    2016-07-15

    The antagonism between cyclin-dependent kinases (Cdks) and the ubiquitin ligase APC/C-Cdh1 is central to eukaryotic cell cycle control. APC/C-Cdh1 targets cyclin B and other regulatory proteins for degradation, whereas Cdks disable APC/C-Cdh1 through phosphorylation of the Cdh1 activator protein at multiple sites. Budding yeast Cdh1 carries nine Cdk phosphorylation sites in its N-terminal regulatory domain, most or all of which contribute to inhibition. However, the precise role of individual sites has remained unclear. Here, we report that the Cdk phosphorylation sites of yeast Cdh1 are organized into autonomous subgroups and act through separate mechanisms. Cdk sites 1-3 had no direct effect on the APC/C binding of Cdh1 but inactivated a bipartite nuclear localization sequence (NLS) and thereby controlled the partitioning of Cdh1 between cytoplasm and nucleus. In contrast, Cdk sites 4-9 did not influence the cell cycle-regulated localization of Cdh1 but prevented its binding to the APC/C. Cdk sites 4-9 reside near two recently identified APC/C interaction motifs in a pattern conserved with the human Cdh1 orthologue. Thus a Cdk-inhibited NLS goes along with Cdk-inhibited APC/C binding sites in yeast Cdh1 to relay the negative control by Cdk1 phosphorylation of the ubiquitin ligase APC/C-Cdh1.

  19. Degradation of Ndd1 by APC/C(Cdh1) generates a feed forward loop that times mitotic protein accumulation.

    PubMed

    Sajman, Julia; Zenvirth, Drora; Nitzan, Mor; Margalit, Hanah; Simpson-Lavy, Kobi J; Reiss, Yuval; Cohen, Itamar; Ravid, Tommer; Brandeis, Michael

    2015-05-11

    Ndd1 activates the Mcm1-Fkh2 transcription factor to transcribe mitotic regulators. The anaphase-promoting complex/cyclosome activated by Cdh1 (APC/C(Cdh1)) mediates the degradation of proteins throughout G1. Here we show that the APC/C(Cdh1) ubiquitinates Ndd1 and mediates its degradation, and that APC/C(Cdh1) activity suppresses accumulation of Ndd1 targets. We confirm putative Ndd1 targets and identify novel ones, many of them APC/C(Cdh1) substrates. The APC/C(Cdh1) thus regulates these proteins in a dual manner—both pretranscriptionally and post-translationally, forming a multi-layered feedforward loop (FFL). We predict by mathematical modelling and verify experimentally that this FFL introduces a lag between APC/C(Cdh1) inactivation at the end of G1 and accumulation of genes transcribed by Ndd1 in G2. This regulation generates two classes of APC/C(Cdh1) substrates, early ones that accumulate in S and late ones that accumulate in G2. Our results show how the dual state APC/C(Cdh1) activity is converted into multiple outputs by interactions between its substrates.

  20. Meta-analysis of the association between APC promoter methylation and colorectal cancer

    PubMed Central

    Ding, Zhenyu; Jiang, Tong; Piao, Ying; Han, Tao; Han, Yaling; Xie, Xiaodong

    2015-01-01

    Previous studies investigating the association between adenomatous polyposis coli (APC) gene promoter methylation and colorectal cancer (CRC) have yielded conflicting results. The aim of this study was to comprehensively evaluate the potential application of the detection of APC promoter methylation to the prevention and treatment of CRC. PubMed, Embase, and MEDLINE (results updated to October 2014) were searched for relevant studies. The effect size was defined as the weighted odds ratio (OR), which was calculated using either the fixed-effects or random-effects model. Prespecified subgroup and sensitivity analyses were conducted to evaluate potential heterogeneity among the included studies. Nineteen studies comprising 2,426 participants were selected for our meta-analysis. The pooled results of nine studies comprising a total of 740 subjects indicated that APC promoter methylation was significantly associated with CRC risk (pooled OR 5.53; 95% confidence interval [CI] 3.50–8.76; P<0.01). Eleven studies with a total of 1,219 patients evaluated the association between APC promoter methylation and the presence of CRC metastasis, and the pooled OR was 0.80 (95% CI 0.44–1.46; P=0.47). A meta-analysis conducted with four studies with a total of 467 patients found no significant correlation between APC promoter methylation and the presence of colorectal adenoma (pooled OR 1.85; 95% CI 0.67–5.10; P=0.23). No significant correlation between APC promoter methylation and patients’ Dukes’ stage, TNM stage, differentiation grade, age, or sex was identified. In conclusion, APC promoter methylation was found to be significantly associated with a higher risk of developing CRC. The findings indicate that APC promoter methylation may be a potential biomarker for the carcinogenesis of CRC. PMID:25632237

  1. Meta-analysis of the association between APC promoter methylation and colorectal cancer.

    PubMed

    Ding, Zhenyu; Jiang, Tong; Piao, Ying; Han, Tao; Han, Yaling; Xie, Xiaodong

    2015-01-01

    Previous studies investigating the association between adenomatous polyposis coli (APC) gene promoter methylation and colorectal cancer (CRC) have yielded conflicting results. The aim of this study was to comprehensively evaluate the potential application of the detection of APC promoter methylation to the prevention and treatment of CRC. PubMed, Embase, and MEDLINE (results updated to October 2014) were searched for relevant studies. The effect size was defined as the weighted odds ratio (OR), which was calculated using either the fixed-effects or random-effects model. Prespecified subgroup and sensitivity analyses were conducted to evaluate potential heterogeneity among the included studies. Nineteen studies comprising 2,426 participants were selected for our meta-analysis. The pooled results of nine studies comprising a total of 740 subjects indicated that APC promoter methylation was significantly associated with CRC risk (pooled OR 5.53; 95% confidence interval [CI] 3.50-8.76; P<0.01). Eleven studies with a total of 1,219 patients evaluated the association between APC promoter methylation and the presence of CRC metastasis, and the pooled OR was 0.80 (95% CI 0.44-1.46; P=0.47). A meta-analysis conducted with four studies with a total of 467 patients found no significant correlation between APC promoter methylation and the presence of colorectal adenoma (pooled OR 1.85; 95% CI 0.67-5.10; P=0.23). No significant correlation between APC promoter methylation and patients' Dukes' stage, TNM stage, differentiation grade, age, or sex was identified. In conclusion, APC promoter methylation was found to be significantly associated with a higher risk of developing CRC. The findings indicate that APC promoter methylation may be a potential biomarker for the carcinogenesis of CRC.

  2. Regulation of APC development, immune response, and autoimmunity by Bach1/HO-1 pathway in mice

    PubMed Central

    So, Alex Yick-Lun; Garcia-Flores, Yvette; Minisandram, Aarathi; Martin, Ayana; Taganov, Konstantin; Boldin, Mark

    2012-01-01

    APCs are essential for innate and adaptive immunity as well as self-immune tolerance. Here, we show that the Cap'n'collar member Bach1 regulates the generation of APCs, specifically macrophages and dendritic cells, in mice. The impaired APC development in Bach1−/− mice was accompanied by defects in downstream T-cell responses and partial protection from experimental autoimmune encephalomyelitis. Genomewide analyses identified a panel of Bach1 target genes and ablation of the direct Bach1 target gene HO-1 exacerbated the impaired APC development observed in Bach1−/− mice. This was attributed to the impaired ability of HO-1−/−Bach1−/− double mutants to produce upstream APC progenitor cells, including common myeloid progenitor (CMP)–Flk2+. By contrast, we observed an increase in hematopoietic stem-progenitor cells (HSPCs) in these mice, suggesting a developmental block in the progression of HSPCs to CMP-Flk2+ and subsequently APCs. PMID:22791292

  3. Structure of an APC3–APC16 Complex: Insights into Assembly of the Anaphase-Promoting Complex/Cyclosome

    SciTech Connect

    Yamaguchi, Masaya; Yu, Shanshan; Qiao, Renping; Weissmann, Florian; Miller, Darcie J.; VanderLinden, Ryan; Brown, Nicholas G.; Frye, Jeremiah J.; Peters, Jan-Michael; Schulman, Brenda A.

    2014-12-06

    The anaphase-promoting complex/cyclosome (APC/C) is a massive E3 ligase that controls mitosis by catalyzing ubiquitination of key cell cycle regulatory proteins. The APC/C assembly contains two subcomplexes: the “Platform” centers around a cullin-RING-like E3 ligase catalytic core; the “Arc Lamp” is a hub that mediates transient association with regulators and ubiquitination substrates. The Arc Lamp contains the small subunits APC16, CDC26, and APC13, and tetratricopeptide repeat (TPR) proteins (APC7, APC3, APC6, and APC8) that homodimerize and stack with quasi-2-fold symmetry. Within the APC/C complex, APC3 serves as center for regulation. APC3's TPR motifs recruit substrate-binding coactivators, CDC20 and CDH1, via their C-terminal conserved Ile-Arg (IR) tail sequences. Human APC3 also binds APC16 and APC7 and contains a > 200-residue loop that is heavily phosphorylated during mitosis, although the basis for APC3 interactions and whether loop phosphorylation is required for ubiquitination are unclear. Here, we map the basis for human APC3 assembly with APC16 and APC7, report crystal structures of APC3Δloop alone and in complex with the C-terminal domain of APC16, and test roles of APC3's loop and IR tail binding surfaces in APC/C-catalyzed ubiquitination. The structures show how one APC16 binds asymmetrically to the symmetric APC3 dimer and, together with biochemistry and prior data, explain how APC16 recruits APC7 to APC3, show how APC3's C-terminal domain is rearranged in the full APC/C assembly, and visualize residues in the IR tail binding cleft important for coactivator-dependent ubiquitination. Overall, the results provide insights into assembly, regulation, and interactions of TPR proteins and the APC/C.

  4. Structure of an APC3–APC16 Complex: Insights into Assembly of the Anaphase-Promoting Complex/Cyclosome

    DOE PAGES

    Yamaguchi, Masaya; Yu, Shanshan; Qiao, Renping; ...

    2014-12-06

    The anaphase-promoting complex/cyclosome (APC/C) is a massive E3 ligase that controls mitosis by catalyzing ubiquitination of key cell cycle regulatory proteins. The APC/C assembly contains two subcomplexes: the “Platform” centers around a cullin-RING-like E3 ligase catalytic core; the “Arc Lamp” is a hub that mediates transient association with regulators and ubiquitination substrates. The Arc Lamp contains the small subunits APC16, CDC26, and APC13, and tetratricopeptide repeat (TPR) proteins (APC7, APC3, APC6, and APC8) that homodimerize and stack with quasi-2-fold symmetry. Within the APC/C complex, APC3 serves as center for regulation. APC3's TPR motifs recruit substrate-binding coactivators, CDC20 and CDH1, viamore » their C-terminal conserved Ile-Arg (IR) tail sequences. Human APC3 also binds APC16 and APC7 and contains a > 200-residue loop that is heavily phosphorylated during mitosis, although the basis for APC3 interactions and whether loop phosphorylation is required for ubiquitination are unclear. Here, we map the basis for human APC3 assembly with APC16 and APC7, report crystal structures of APC3Δloop alone and in complex with the C-terminal domain of APC16, and test roles of APC3's loop and IR tail binding surfaces in APC/C-catalyzed ubiquitination. The structures show how one APC16 binds asymmetrically to the symmetric APC3 dimer and, together with biochemistry and prior data, explain how APC16 recruits APC7 to APC3, show how APC3's C-terminal domain is rearranged in the full APC/C assembly, and visualize residues in the IR tail binding cleft important for coactivator-dependent ubiquitination. Overall, the results provide insights into assembly, regulation, and interactions of TPR proteins and the APC/C.« less

  5. Structure of an APC3–APC16 Complex: Insights into Assembly of the Anaphase-Promoting Complex/Cyclosome

    SciTech Connect

    Yamaguchi, Masaya; Yu, Shanshan; Qiao, Renping; Weissmann, Florian; Miller, Darcie J.; VanderLinden, Ryan; Brown, Nicholas G.; Frye, Jeremiah J.; Peters, Jan-Michael; Schulman, Brenda A.

    2015-08-21

    The anaphase-promoting complex/cyclosome (APC/C) is a massive E3 ligase that controls mitosis by catalyzing ubiquitination of key cell cycle regulatory proteins. The APC/C assembly contains two subcomplexes: the “Platform” centers around a cullin-RING-like E3 ligase catalytic core; the “Arc Lamp” is a hub that mediates transient association with regulators and ubiquitination substrates. The Arc Lamp contains the small subunits APC16, CDC26, and APC13, and tetratricopeptide repeat (TPR) proteins (APC7, APC3, APC6, and APC8) that homodimerize and stack with quasi-2-fold symmetry. Within the APC/C complex, APC3 serves as center for regulation. APC3's TPR motifs recruit substrate-binding coactivators, CDC20 and CDH1, via their C-terminal conserved Ile-Arg (IR) tail sequences. Human APC3 also binds APC16 and APC7 and contains a > 200-residue loop that is heavily phosphorylated during mitosis, although the basis for APC3 interactions and whether loop phosphorylation is required for ubiquitination are unclear. Here, we map the basis for human APC3 assembly with APC16 and APC7, report crystal structures of APC3Δloop alone and in complex with the C-terminal domain of APC16, and test roles of APC3's loop and IR tail binding surfaces in APC/C-catalyzed ubiquitination. The structures show how one APC16 binds asymmetrically to the symmetric APC3 dimer and, together with biochemistry and prior data, explain how APC16 recruits APC7 to APC3, show how APC3's C-terminal domain is rearranged in the full APC/C assembly, and visualize residues in the IR tail binding cleft important for coactivator-dependent ubiquitination. Overall, the results provide insights into assembly, regulation, and interactions of TPR proteins and the APC/C.

  6. Human germline gene therapy reconsidered.

    PubMed

    Resnik, D B; Langer, P J

    2001-07-20

    This paper reevaluates the notion of human germline gene therapy (HGLGT) in light of developments in biomedicine, biotechnology, and ethical and policy analysis. The essay makes the following key points. First, because the distinction among "therapy," "prevention," and "enhancement" is not clear in human genetics, "gene therapy" is an inadequate descriptor of the process and goals of germline genetic alterations. The alternate use of the phrase "human germline genome modification" (HGLGM) could avoid a misleading label. Second, procedures that could be construed as genetic "enhancement" may not be as morally problematic as some have supposed, once one understands that the boundaries between therapy, prevention, and enhancement are not obvious in genetic medicine. Third, HGLGM might be the medically and morally most appropriate way of avoiding the birth of a child with a genetic disease in only a small range of cases. Fourth, there are still many ethical and scientific problems relating to the safety and efficacy of HGLGM.

  7. APC promoter 1B deletion in seven American families with familial adenomatous polyposis.

    PubMed

    Snow, A K; Tuohy, T M F; Sargent, N R; Smith, L J; Burt, R W; Neklason, D W

    2015-10-01

    Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome caused by mutations in the adenomatous polyposis coli (APC) gene. Clinical genetic testing fails to identify disease causing mutations in up to 20% of clinically apparent FAP cases. Following the inclusion of multiplex ligation-dependent probe amplification (MLPA) probes specific for APC promoter 1B, seven probands were identified with a deletion of promoter 1B. Using haplotype analysis spanning the APC locus, the seven families appear to be identical by descent from a common founder. The clinical phenotype of 19 mutation carriers is classical FAP with colectomy at an average age of 24. The majority of cases had a large number of duodenal and gastric polyps. Measurements of allele-specific expression of APC mRNA using TaqMan assay confirmed that relative expression in the allele containing the promoter 1B deletion was reduced 42-98%, depending on tissue type. This study confirms the importance of APC promoter deletions as a cause of FAP and identifies a founder mutation in FAP patients from the United States. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Dietary factors and truncating APC mutations in sporadic colorectal adenomas.

    PubMed

    Diergaarde, Brenda; Tiemersma, Edine W; Braam, Hanneke; van Muijen, Goos N P; Nagengast, Fokko M; Kok, Frans J; Kampman, Ellen

    2005-01-01

    Inactivating mutations in APC are thought to be early, initiating events in colorectal carcinogenesis. To gain insight into the relationship between diet and inactivating APC mutations, we evaluated associations between dietary factors and the occurrence of these mutations in a Dutch case-control study of sporadic colorectal adenomas (278 cases; 414 polyp-free controls). Direct-sequencing was used to screen adenomas for mutations in the mutation cluster region of APC; truncating mutations were detected in 161 (58%) of the adenomas. Red meat consumption was significantly differently related to polyps with truncating APC mutation (APC(+) polyps) compared to polyps without truncating APC mutation (APC(-) polyps) (highest vs. lowest tertile, odds ratio [OR] = 0.5, 95% confidence interval [CI] = 0.3-1.0). High intake of red meat and fat seemed to increase the risk of APC(-) polyps only (APC(+) vs. controls: red meat, OR = 1.0, 95% CI = 0.6-1.6; fat, OR = 1.1, 95% CI = 0.6-1.9; APC(-) vs. controls: red meat, OR = 1.8, 95% CI = 1.0-3.1; fat, OR = 1.9, 95% CI = 1.0-3.7). Intake of carbohydrates was inversely associated with both polyp groups, most noticeably with APC(-) polyps. Most other evaluated dietary factors were not distinctively associated with a specific APC status. None of the dietary factors was specifically associated with a particular type of truncating APC mutation. Our data suggest that red meat and fat may increase the risk of APC(-) polyps in particular, whereas carbohydrates may especially decrease the risk of APC(-) polyps. However, most examined dietary factors do not appear to be specifically associated with the occurrence of truncating APC mutations in colorectal adenomas but seem to affect both pathways equally.

  9. Germline engineering: the moral challenges.

    PubMed

    Engelhardt, H Tristram

    2002-03-01

    Not only is the use of germline genetic engineering likely in the long run to be inevitable, there are also no convincing secular moral grounds to forbid this technology in principle. Instead, the general secular moral constraints on the use of germline genetic engineering are either procedural or without predetermined content. Nor can one develop a coherent distinction between eliminating disease and enhancing human abilities. At best, in secular morality one can establish the principle to proceed with care, though the invocation of the precautionary principle argues as much in favor of the development of germline genetic engineering as against its use. Because germline genetic engineering, by eliminating certain genetic defects, offers the prospect of decreasing human suffering and decreasing the use of prenatal diagnosis and abortion, there is an obligation, all else being equal, to change the human genome. In a post-modern world, humans face the challenge of directing their own evolution, although they share no common understanding of human destiny and purpose. Such understandings, though available within religious contexts, are not available to secular bioethics. Copyright 2002 Wiley-Liss, Inc.

  10. Structural analysis sheds light on APC/C-mediated ubiquitylation.

    PubMed

    Kimata, Yuu; Yamano, Hiroyuki

    2006-01-01

    In the December 22nd issue of Molecular Cell, two groups report refined cryo-electron microscopic structures of the APC/C at approximately 20 A resolution. They also reveal important new features including multiple copies of subunits, dimerization and structural flexibility of the APC/C, which give a hint to solve the mechanisms of the APC/C-dependent ubiquitylation.

  11. Co-regulation proteomics reveals substrates and mechanisms of APC/C-dependent degradation

    PubMed Central

    Singh, Sasha A; Winter, Dominic; Kirchner, Marc; Chauhan, Ruchi; Ahmed, Saima; Ozlu, Nurhan; Tzur, Amit; Steen, Judith A; Steen, Hanno

    2014-01-01

    Using multiplexed quantitative proteomics, we analyzed cell cycle-dependent changes of the human proteome. We identified >4,400 proteins, each with a six-point abundance profile across the cell cycle. Hypothesizing that proteins with similar abundance profiles are co-regulated, we clustered the proteins with abundance profiles most similar to known Anaphase-Promoting Complex/Cyclosome (APC/C) substrates to identify additional putative APC/C substrates. This protein profile similarity screening (PPSS) analysis resulted in a shortlist enriched in kinases and kinesins. Biochemical studies on the kinesins confirmed KIFC1, KIF18A, KIF2C, and KIF4A as APC/C substrates. Furthermore, we showed that the APC/CCDH1-dependent degradation of KIFC1 regulates the bipolar spindle formation and proper cell division. A targeted quantitative proteomics experiment showed that KIFC1 degradation is modulated by a stabilizing CDK1-dependent phosphorylation site within the degradation motif of KIFC1. The regulation of KIFC1 (de-)phosphorylation and degradation provides insights into the fidelity and proper ordering of substrate degradation by the APC/C during mitosis. PMID:24510915

  12. Lessons for Inductive Germline Determination

    PubMed Central

    Seervai, Riyad N.H.; Wessel, Gary M.

    2015-01-01

    SUMMARY Formation of the germline in an embryo marks a fresh round of reproductive potential, yet the developmental stage and location within the embryo where the primordial germ cells (PGCs) form differs wildly among species. In most animals, the germline is formed either by an inherited mechanism, in which maternal provisions within the oocyte drive localized germ-cell fate once acquired in the embryo, or an inductive mechanism that involves signaling between cells that directs germ-cell fate. The inherited mechanism has been widely studied in model organisms such as Drosophila melanogaster, Caenorhabditis elegans, Xenopus laevis, and Danio rerio. Given the rapid generation time and the effective adaptation for laboratory research of these organisms, it is not coincidental that research on these organisms has led the field in elucidating mechanisms for germline specification. The inductive mechanism, however, is less well understood and is studied primarily in the mouse (Mus musculus). In this review, we compare and contrast these two fundamental mechanisms for germline determination, beginning with the key molecular determinants that play a role in the formation of germ cells across all animal taxa. We next explore the current understanding of the inductive mechanism of germ-cell determination in mice, and evaluate the hypotheses for selective pressures on these contrasting mechanisms. We then discuss the hypothesis that the transition between these determination mechanisms, which has happened many times in phylogeny, is more of a continuum than a binary change. Finally, we propose an analogy between germline determination and sex determination in vertebrates—two of the milestones of reproduction and development—in which animals use contrasting strategies to activate similar pathways. PMID:23450642

  13. Lessons for inductive germline determination.

    PubMed

    Seervai, Riyad N H; Wessel, Gary M

    2013-08-01

    Formation of the germline in an embryo marks a fresh round of reproductive potential, yet the developmental stage and location within the embryo where the primordial germ cells (PGCs) form differs wildly among species. In most animals, the germline is formed either by an inherited mechanism, in which maternal provisions within the oocyte drive localized germ-cell fate once acquired in the embryo, or an inductive mechanism that involves signaling between cells that directs germ-cell fate. The inherited mechanism has been widely studied in model organisms such as Drosophila melanogaster, Caenorhabditis elegans, Xenopus laevis, and Danio rerio. Given the rapid generation time and the effective adaptation for laboratory research of these organisms, it is not coincidental that research on these organisms has led the field in elucidating mechanisms for germline specification. The inductive mechanism, however, is less well understood and is studied primarily in the mouse (Mus musculus). In this review, we compare and contrast these two fundamental mechanisms for germline determination, beginning with the key molecular determinants that play a role in the formation of germ cells across all animal taxa. We next explore the current understanding of the inductive mechanism of germ-cell determination in mice, and evaluate the hypotheses for selective pressures on these contrasting mechanisms. We then discuss the hypothesis that the transition between these determination mechanisms, which has happened many times in phylogeny, is more of a continuum than a binary change. Finally, we propose an analogy between germline determination and sex determination in vertebrates-two of the milestones of reproduction and development-in which animals use contrasting strategies to activate similar pathways.

  14. Germline Variants in Targeted Tumor Sequencing Using Matched Normal DNA.

    PubMed

    Schrader, Kasmintan A; Cheng, Donavan T; Joseph, Vijai; Prasad, Meera; Walsh, Michael; Zehir, Ahmet; Ni, Ai; Thomas, Tinu; Benayed, Ryma; Ashraf, Asad; Lincoln, Annie; Arcila, Maria; Stadler, Zsofia; Solit, David; Hyman, David M; Hyman, David; Zhang, Liying; Klimstra, David; Ladanyi, Marc; Offit, Kenneth; Berger, Michael; Robson, Mark

    2016-01-01

    Tumor genetic sequencing identifies potentially targetable genetic alterations with therapeutic implications. Analysis has concentrated on detecting tumor-specific variants, but recognition of germline variants may prove valuable as well. To estimate the burden of germline variants identified through routine clinical tumor sequencing. Patients with advanced cancer diagnoses eligible for studies of targeted agents at Memorial Sloan Kettering Cancer Center are offered tumor-normal sequencing with MSK-IMPACT, a 341-gene panel. We surveyed the germline variants seen in 187 overlapping genes with Mendelian disease associations in 1566 patients who had undergone tumor profiling between March and October 2014. The number of presumed pathogenic germline variants (PPGVs) and variants of uncertain significance per person in 187 genes associated with single-gene disorders and the proportions of individuals with PPGVs in clinically relevant gene subsets, in genes consistent with known tumor phenotypes, and in genes with evidence of second somatic hits in their tumors. The mean age of the 1566 patients was 58 years, and 54% were women. Presumed pathogenic germline variants in known Mendelian disease-associated genes were identified in 246 of 1566 patients (15.7%; 95% CI, 14.0%-17.6%), including 198 individuals with mutations in genes associated with cancer susceptibility. Germline findings in cancer susceptibility genes were concordant with the individual's cancer type in only 81 of 198 cases (40.9%; 95% CI, 34.3%-47.9%). In individuals with PPGVs retained in the tumor, somatic alteration of the other allele was seen in 39 of 182 cases (21.4%; 95% CI, 16.1%-28.0%), of which 13 cases did not show a known correlation of the germline mutation and a known syndrome. Mutations in non-cancer-related Mendelian disease genes were seen in 55 of 1566 cases (3.5%; 95% CI, 27.1%-45.4%). Almost every individual had more than 1 variant of uncertain significance (1565 of 1566 patients; 99

  15. IFSO-APC consensus statements 2011.

    PubMed

    Kasama, Kazunori; Mui, Wilfred; Lee, Wei Jei; Lakdawala, Muffazal; Naitoh, Takeshi; Seki, Yosuke; Sasaki, Akira; Wakabayashi, Go; Sasaki, Iwao; Kawamura, Isao; Kow, Lilian; Frydenberg, Harry; Chen, Anton; Narwaria, Mahendra; Chowbey, Pradeep

    2012-05-01

    Associations of BMI with body composition and health outcomes may differ between Asian and European populations. Asian populations have also been shown to have an elevated risk of type 2 diabetes, hypertension, and hyperlipidemia at a relatively low level of BMI. New surgical indication for Asian patients should be discussed by the expert of this field. Forty-four bariatric experts in Asia-Pacific and other regions were chosen to have a voting privilege for IFSO-APC Consensus at the 2nd IFSO-APC Congress. A computerized audience-response voting system was used to analyze the agreement with the sentence of the consensus. Of all delegates, 95% agreed with the necessity of the establishment of IFSO-APC consensus statements, and 98% agreed with the necessity of a new indication for Asian patients. IFSO-APC Consensus statements 2011. Bariatric surgery should be considered for the treatment of obesity for acceptable Asian candidates with BMI ≥ 35 with or without co-morbidities. Bariatric/GI metabolic surgery should be considered for the treatment of T2DM or metabolic syndrome for patients who are inadequately controlled by lifestyle alternations and medical treatment for acceptable Asian candidates with BMI ≥ 30. The surgical approach may be considered as a non-primary alternative to treat inadequately controlled T2DM, or metabolic syndrome, for suitable Asian candidates with BMI ≥ 27.5. Other eight sentences are agreed with by majority of the voting delegates to form IFSO-APC consensus statements. This will help to make safe and wholesome the progress of bariatric and metabolic surgery in Asia.

  16. Frequency and phenotypic spectrum of germline mutations in POLE and seven other polymerase genes in 266 patients with colorectal adenomas and carcinomas.

    PubMed

    Spier, Isabel; Holzapfel, Stefanie; Altmüller, Janine; Zhao, Bixiao; Horpaopan, Sukanya; Vogt, Stefanie; Chen, Sophia; Morak, Monika; Raeder, Susanne; Kayser, Katrin; Stienen, Dietlinde; Adam, Ronja; Nürnberg, Peter; Plotz, Guido; Holinski-Feder, Elke; Lifton, Richard P; Thiele, Holger; Hoffmann, Per; Steinke, Verena; Aretz, Stefan

    2015-07-15

    In a number of families with colorectal adenomatous polyposis or suspected Lynch syndrome/HNPCC, no germline alteration in the APC, MUTYH, or mismatch repair (MMR) genes are found. Missense mutations in the polymerase genes POLE and POLD1 have recently been identified as rare cause of multiple colorectal adenomas and carcinomas, a condition termed polymerase proofreading-associated polyposis (PPAP). The aim of the present study was to evaluate the clinical relevance and phenotypic spectrum of polymerase germline mutations. Therefore, targeted sequencing of the polymerase genes POLD1, POLD2, POLD3, POLD4, POLE, POLE2, POLE3 and POLE4 was performed in 266 unrelated patients with polyposis or fulfilled Amsterdam criteria. The POLE mutation c.1270C>G;p.Leu424Val was detected in four unrelated patients. The mutation was present in 1.5% (4/266) of all patients, 4% (3/77) of all familial cases and 7% (2/30) of familial polyposis cases. The colorectal phenotype in 14 affected individuals ranged from typical adenomatous polyposis to a HNPCC phenotype, with high intrafamilial variability. Multiple colorectal carcinomas and duodenal adenomas were common, and one case of duodenal carcinoma was reported. Additionally, various extraintestinal lesions were evident. Nine further putative pathogenic variants were identified. The most promising was c.1306C>T;p.Pro436Ser in POLE. In conclusion, a PPAP was identified in a substantial number of polyposis and familial colorectal cancer patients. Screening for polymerase proofreading mutations should therefore be considered, particularly in unexplained familial cases. The present study broadens the phenotypic spectrum of PPAP to duodenal adenomas and carcinomas, and identified novel, potentially pathogenic variants in four polymerase genes. © 2014 UICC.

  17. Increased biomass production and glycogen accumulation in apcE gene deleted Synechocystis sp. PCC 6803.

    PubMed

    Joseph, Ancy; Aikawa, Shimpei; Sasaki, Kengo; Matsuda, Fumio; Hasunuma, Tomohisa; Kondo, Akihiko

    2014-01-01

    The effect of phycobilisome antenna-truncation in the cyanobacterium Synechocystis sp. PCC 6803 on biomass production and glycogen accumulation have not yet been fully clarified. To investigate these effects here, the apcE gene, which encodes the anchor protein linking the phycobilisome to the thylakoid membrane, was deleted in a glucose tolerant strain of Synechocystis sp. PCC 6803. Biomass production of the apcE-deleted strain under photoautotrophic and atmospheric air conditions was 1.6 times higher than that of strain PCC 6803 (1.32 ± 0.01 versus 0.84 ± 0.07 g cell-dry weight L(-1), respectively) after 15 days of cultivation. In addition, the glycogen content of the apcE-deleted strain (24.2 ± 0.7%) was also higher than that of strain PCC 6803 (11.1 ± 0.3%). Together, these results demonstrate that antenna truncation by deleting the apcE gene was effective for increasing biomass production and glycogen accumulation under photoautotrophic and atmospheric air conditions in Synechocystis sp. PCC 6803.

  18. Targeting of Fzr/Cdh1 for timely activation of the APC/C at the centrosome during mitotic exit

    PubMed Central

    Meghini, Francesco; Martins, Torcato; Tait, Xavier; Fujimitsu, Kazuyuki; Yamano, Hiroyuki; Glover, David M.; Kimata, Yuu

    2016-01-01

    A multi-subunit ubiquitin ligase, the anaphase-promoting complex/cyclosome (APC/C), regulates critical cellular processes including the cell cycle. To accomplish its diverse functions, APC/C activity must be precisely regulated in time and space. The interphase APC/C activator Fizzy-related (Fzr or Cdh1) is localized at centrosomes in animal cells. However, neither the mechanism of its localization nor its importance is clear. Here we identify the centrosome component Spd2 as a major partner of Fzr in Drosophila. The localization of Fzr to the centriole during interphase depends on direct interaction with Spd2. By generating Spd2 mutants unable to bind Fzr, we show that centrosomal localization of Fzr is essential for optimal APC/C activation towards its centrosomal substrate Aurora A. Finally, we show that Spd2 is also a novel APC/CFzr substrate. Our study is the first to demonstrate the critical importance of distinct subcellular pools of APC/C activators in the spatiotemporal control of APC/C activity. PMID:27558644

  19. Effete-mediated degradation of Cyclin A is essential for the maintenance of germline stem cells in Drosophila.

    PubMed

    Chen, Dongsheng; Wang, Qi; Huang, Haidong; Xia, Laixin; Jiang, Xiaoyong; Kan, Lijuan; Sun, Qinmiao; Chen, Dahua

    2009-12-01

    Increasing evidence supports the idea that the regulation of stem cells requires both extrinsic and intrinsic mechanisms. However, much less is known about how intrinsic signals regulate the fate of stem cells. Studies on germline stem cells (GSCs) in the Drosophila ovary have provided novel insights into the regulatory mechanisms of stem cell maintenance. In this study, we demonstrate that a ubiquitin-dependent pathway mediated by the Drosophila eff gene, which encodes the E2 ubiquitin-conjugating enzyme Effete (Eff), plays an essential role in GSC maintenance. We show that Eff both physically and genetically interacts with dAPC2, a key component of the anaphase-promoting complex (APC), which acts as a multisubunit E3 ligase and plays an essential role in targeting mitotic regulators for degradation during exit from mitosis. This interaction indicates that Eff regulates the APC/C-mediated proteolysis pathway in GSCs. Moreover, we show that expression of a stable form of Cyclin A, but not full-length Cyclin A, results in GSC loss. Finally we show that, in common with APC2, Eff is required for the ubiquitylation of Cyclin A, and overexpression of full-length Cyclin A accelerates the loss of GSCs in the eff mutant background. Collectively, our data support the idea that Effete/APC-mediated degradation of Cyclin A is essential for the maintenance of germline stem cells in Drosophila. Given that the regulation of mitotic Cyclins is evolutionarily conserved between flies and mammals, our study also implies that a similar mechanism may be conserved in mammals.

  20. Approaches to integrating germline and tumor genomic data in cancer research

    PubMed Central

    Feigelson, Heather Spencer; Goddard, Katrina A.B.; Hollombe, Celine; Tingle, Sharna R.; Gillanders, Elizabeth M.; Mechanic, Leah E.; Nelson, Stefanie A.

    2014-01-01

    Cancer is characterized by a diversity of genetic and epigenetic alterations occurring in both the germline and somatic (tumor) genomes. Hundreds of germline variants associated with cancer risk have been identified, and large amounts of data identifying mutations in the tumor genome that participate in tumorigenesis have been generated. Increasingly, these two genomes are being explored jointly to better understand how cancer risk alleles contribute to carcinogenesis and whether they influence development of specific tumor types or mutation profiles. To understand how data from germline risk studies and tumor genome profiling is being integrated, we reviewed 160 articles describing research that incorporated data from both genomes, published between January 2009 and December 2012, and summarized the current state of the field. We identified three principle types of research questions being addressed using these data: (i) use of tumor data to determine the putative function of germline risk variants; (ii) identification and analysis of relationships between host genetic background and particular tumor mutations or types; and (iii) use of tumor molecular profiling data to reduce genetic heterogeneity or refine phenotypes for germline association studies. We also found descriptive studies that compared germline and tumor genomic variation in a gene or gene family, and papers describing research methods, data sources, or analytical tools. We identified a large set of tools and data resources that can be used to analyze and integrate data from both genomes. Finally, we discuss opportunities and challenges for cancer research that integrates germline and tumor genomics data. PMID:25115441

  1. The actin-binding protein profilin is required for germline stem cell maintenance and germ cell enclosure by somatic cyst cells.

    PubMed

    Shields, Alicia R; Spence, Allyson C; Yamashita, Yukiko M; Davies, Erin L; Fuller, Margaret T

    2014-01-01

    Specialized microenvironments, or niches, provide signaling cues that regulate stem cell behavior. In the Drosophila testis, the JAK-STAT signaling pathway regulates germline stem cell (GSC) attachment to the apical hub and somatic cyst stem cell (CySC) identity. Here, we demonstrate that chickadee, the Drosophila gene that encodes profilin, is required cell autonomously to maintain GSCs, possibly facilitating localization or maintenance of E-cadherin to the GSC-hub cell interface. Germline specific overexpression of Adenomatous Polyposis Coli 2 (APC2) rescued GSC loss in chic hypomorphs, suggesting an additive role of APC2 and F-actin in maintaining the adherens junctions that anchor GSCs to the niche. In addition, loss of chic function in the soma resulted in failure of somatic cyst cells to maintain germ cell enclosure and overproliferation of transit-amplifying spermatogonia.

  2. The actin-binding protein profilin is required for germline stem cell maintenance and germ cell enclosure by somatic cyst cells

    PubMed Central

    Shields, Alicia R.; Spence, Allyson C.; Yamashita, Yukiko M.; Davies, Erin L.; Fuller, Margaret T.

    2014-01-01

    Specialized microenvironments, or niches, provide signaling cues that regulate stem cell behavior. In the Drosophila testis, the JAK-STAT signaling pathway regulates germline stem cell (GSC) attachment to the apical hub and somatic cyst stem cell (CySC) identity. Here, we demonstrate that chickadee, the Drosophila gene that encodes profilin, is required cell autonomously to maintain GSCs, possibly facilitating localization or maintenance of E-cadherin to the GSC-hub cell interface. Germline specific overexpression of Adenomatous Polyposis Coli 2 (APC2) rescued GSC loss in chic hypomorphs, suggesting an additive role of APC2 and F-actin in maintaining the adherens junctions that anchor GSCs to the niche. In addition, loss of chic function in the soma resulted in failure of somatic cyst cells to maintain germ cell enclosure and overproliferation of transit-amplifying spermatogonia. PMID:24346697

  3. Evaluation of TP53 Pro72Arg and MDM2 SNP285-SNP309 polymorphisms in an Italian cohort of LFS suggestive patients lacking identifiable TP53 germline mutations.

    PubMed

    Ponti, Francesca; Corsini, Serena; Gnoli, Maria; Pedrini, Elena; Mordenti, Marina; Sangiorgi, Luca

    2016-10-01

    Li-Fraumeni syndrome (LFS) is a rare genetic cancer predisposition disease, partly determined by the presence of a TP53 germline mutation; lacking thereof, in presence of a typical LFS phenotype, defines a wide group of 'LFS Suggestive' patients. Alternative LFS susceptibility genes have been investigated without promising results, thus suggesting other genetic determinants involvement in cancer predisposition. Hence, this study explores the single and combined effects of cancer risk, age of onset and cancer type of three single nucleotide polymorphisms (SNPs)-TP53 Pro72Arg, MDM2 SNP285 and SNP309-already described as modifiers on TP53 mutation carriers but not properly investigated in LFS Suggestive patients. This case-control study examines 34 Italian LFS Suggestive lacking of germline TP53 mutations and 95 tumour-free subjects. A significant prevalence of homozygous MDM2 SNP309 G in the LFS Suggestive group (p < 0.0005) confirms its contribute to cancer susceptibility, also highlighted in LFS TP53 positive families. Conversely its anticipating role on tumour onset has not been confirmed, as in our results it was associated with the SNP309 T allele. A strong combined outcome with a 'dosage' effect has also been reported for TP53 P72 and MDM2 SNP309 G allele on cancer susceptibility (p < 0.0005). Whereas the MDM2 SNP285 C allele neutralizing effect on MDM2 SNP309 G variant is not evident in our population. Although it needs further evaluations, obtained results strengthen the role of MDM2 SNP309 as a genetic factor in hereditary predisposition to cancer, so improving LFS Suggestive patients management.

  4. Cables1 is a tumor suppressor gene that regulates intestinal tumor progression in Apc(Min) mice.

    PubMed

    Arnason, Thomas; Pino, Maria S; Yilmaz, Omer; Kirley, Sandra D; Rueda, Bo R; Chung, Daniel C; Zukerberg, Lawrence R

    2013-07-01

    The transformation of colonic mucosal epithelium to adenocarcinoma requires progressive oncogene activation and tumor suppressor gene inactivation. Loss of chromosome 18q is common in colon cancer but not in precancerous adenomas. A few candidate tumor suppressor genes have been identified in this region, including CABLES1 at 18q11.2-12.1. This study investigates the role of CABLES1 in an in vivo mouse model of intestinal adenocarcinoma and in human colon cancer cell culture. Apc(Min/+) mice were crossed with mice harboring targeted inactivation of the Cables1 gene (Cables1(-/-)). The intestinal tumor burden and tumor expression of β-catenin and PCNA was compared in Cables1(+/+)Apc(Min/+) and Cables1(-/-)Apc(Min/+) mice. β-catenin activity in human colon cancer cells with CABLES1 inactivation and intestinal progenitor cell function in Cables1(-/-) mice were assayed in vitro. The mean number of small intestinal tumors per mouse was 3.1 ± 0.6 in Cables1(+/+)Apc(Min/+) mice, compared with 32.4 ± 3.5 in the Cables1(-/-)Apc(Min/+) mice (P < 0.0001). Fewer colonic tumors were observed in Cables1(+/+)Apc(Min/+) mice (mean 0.6 ± 0.1) compared with the Cables1(-/-)Apc(Min/+) mice (mean 1.3 ± 0.3, P = 0.01). Tumors from Cables1(-/-)Apc(Min/+) mice demonstrated increased nuclear expression of β-catenin and an increased number of PCNA-positive cells. In vitro studies revealed that CABLES1 deficiency increased β-catenin dependent transcription and increased intestinal progenitor cell activity. Loss of Cables1 enhances tumor progression in the Apc(Min/+) mouse model and activates the Wnt/β-catenin signaling pathway. Cables1 is a tumor suppressor gene on chromosome 18q in this in vivo mouse model and likely has a similar role in human colon cancer.

  5. Dietary fat overcomes the protective activity of thrombospondin-1 signaling in the ApcMin/+ model of colon cancer

    PubMed Central

    Soto-Pantoja, D R; Sipes, J M; Martin-Manso, G; Westwood, B; Morris, N L; Ghosh, A; Emenaker, N J; Roberts, D D

    2016-01-01

    Thrombospondin 1 is a glycoprotein that regulates cellular phenotype through interactions with its cellular receptors and extracellular matrix-binding partners. Thrombospondin 1 locally regulates angiogenesis and inflammatory responses that contribute to colorectal carcinogenesis in ApcMin/+ mice. The ability of thrombospondin 1 to regulate responses of cells and tissues to a variety of stresses suggested that loss of thrombospondin 1 may also have broader systemic effects on metabolism to modulate carcinogenesis. ApcMin/+:Thbs1−/− mice exhibited decreased survival and higher tumor multiplicities in the small and large intestine relative to ApcMin/+ mice when fed a low (5%) fat western diet. However, the protective effect of endogenous thrombospondin 1 was lost when the mice were fed a western diet containing 21% fat. Biochemical profiles of liver tissue identified systemic metabolic changes accompanying the effects of thrombospondin 1 and dietary lipid intake on tumorigenesis. A high-fat western diet differentially regulated elements of amino acid, energy and lipid metabolism in ApcMin/+:Thbs1−/− mice relative to ApcMin/+:Thbs1+/+mice. Metabolic changes in ketone body and tricarboxylic acid cycle intermediates indicate functional interactions between Apc and thrombospondin 1 signaling that control mitochondrial function. The cumulative diet-dependent differential changes observed in ApcMin/+:Thbs1−/− versus ApcMin/+ mice include altered amino acid and lipid metabolism, mitochondrial dysfunction, eicosanoids and ketone body formation. This metabolic profile suggests that the protective role of thrombospondin 1 to decrease adenoma formation in ApcMin/+ mice results in part from improved mitochondrial function. PMID:27239962

  6. Dietary fat overcomes the protective activity of thrombospondin-1 signaling in the Apc(Min/+) model of colon cancer.

    PubMed

    Soto-Pantoja, D R; Sipes, J M; Martin-Manso, G; Westwood, B; Morris, N L; Ghosh, A; Emenaker, N J; Roberts, D D

    2016-05-30

    Thrombospondin 1 is a glycoprotein that regulates cellular phenotype through interactions with its cellular receptors and extracellular matrix-binding partners. Thrombospondin 1 locally regulates angiogenesis and inflammatory responses that contribute to colorectal carcinogenesis in Apc(Min/+) mice. The ability of thrombospondin 1 to regulate responses of cells and tissues to a variety of stresses suggested that loss of thrombospondin 1 may also have broader systemic effects on metabolism to modulate carcinogenesis. Apc(Min/+):Thbs1(-/-) mice exhibited decreased survival and higher tumor multiplicities in the small and large intestine relative to Apc(Min/+) mice when fed a low (5%) fat western diet. However, the protective effect of endogenous thrombospondin 1 was lost when the mice were fed a western diet containing 21% fat. Biochemical profiles of liver tissue identified systemic metabolic changes accompanying the effects of thrombospondin 1 and dietary lipid intake on tumorigenesis. A high-fat western diet differentially regulated elements of amino acid, energy and lipid metabolism in Apc(Min/+):Thbs1(-/-) mice relative to Apc(Min/+):Thbs1(+/+)mice. Metabolic changes in ketone body and tricarboxylic acid cycle intermediates indicate functional interactions between Apc and thrombospondin 1 signaling that control mitochondrial function. The cumulative diet-dependent differential changes observed in Apc(Min/+):Thbs1(-/-) versus Apc(Min/+) mice include altered amino acid and lipid metabolism, mitochondrial dysfunction, eicosanoids and ketone body formation. This metabolic profile suggests that the protective role of thrombospondin 1 to decrease adenoma formation in Apc(Min/+) mice results in part from improved mitochondrial function.

  7. Regulation of APC/C activators in mitosis and meiosis.

    PubMed

    Pesin, Jillian A; Orr-Weaver, Terry L

    2008-01-01

    The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit E3 ubiquitin ligase that triggers the degradation of multiple substrates during mitosis. Cdc20/Fizzy and Cdh1/Fizzy-related activate the APC/C and confer substrate specificity through complex interactions with both the core APC/C and substrate proteins. The regulation of Cdc20 and Cdh1 is critical for proper APC/C activity and occurs in multiple ways: targeted protein degradation, phosphorylation, and direct binding of inhibitory proteins. During the specialized divisions of meiosis, the activity of the APC/C must be modified to achieve proper chromosome segregation. Recent studies show that one way in which APC/C activity is modified is through the use of meiosis-specific APC/C activators. Furthermore, regulation of the APC/C during meiosis is carried out by both mitotic regulators of the APC/C as well as meiosis-specific regulators. Here, we review the regulation of APC/C activators during mitosis and the role and regulation of the APC/C during female meiosis.

  8. Correlation between germline mutations in MMR genes and microsatellite instability in ovarian cancer specimens.

    PubMed

    Akbari, Mohammad R; Zhang, Shiyu; Cragun, Deborah; Lee, Ji-Hyun; Coppola, Domenico; McLaughlin, John; Risch, Harvey A; Rosen, Barry; Shaw, Patricia; Sellers, Thomas A; Schildkraut, Joellen; Narod, Steven A; Pal, Tuya

    2017-02-07

    A high proportion of ovarian cancers from women who carry germline mutations in mismatch repair (MMR) genes demonstrate microsatellite instability (MSI). The utility of pre-screening ovarian cancer specimens for MSI to identify potential patients for germline screening for MMR mutations is uncertain. 656 women with malignant ovarian cancer underwent both MSI testing and germline mutation testing for large rearrangements in three MMR genes, MLH1, MSH2 and MSH6. Germline DNA sequencing data for the same genes was available. Among the 656 women, only four (0.6%) carried a clearly pathogenic MMR mutation. All four cancers from patients with mutations had loss of two or more microsatellite markers (MSI-high). Eighty-four of 652 (13.0%) women without a mutation had MSI-high ovarian cancers. Using MSI-high as a prescreening criterion, the sensitivity of MSI testing to identify germline MMR gene mutations was 100% and the positive predictive value was 4.5%. Germline mutations in MLH1, MSH2 and MSH6 are rare among unselected cases of ovarian cancer. Patients with germline mutations often will have MSI-positive cancers and pre-screening of ovarian cancer specimens may be an efficient way of identifying patients with Lynch syndrome.

  9. The fate of BRCA1-related germline mutations in triple-negative breast tumors

    PubMed Central

    Kotoula, Vassiliki; Fostira, Florentia; Papadopoulou, Kyriaki; Apostolou, Paraskevi; Tsolaki, Eleftheria; Lazaridis, Georgios; Manoussou, Kyriaki; Zagouri, Flora; Pectasides, Dimitrios; Vlachos, Ioannis; Tikas, Ioannis; Lakis, Sotiris; Konstantopoulou, Irene; Pentheroudakis, George; Gogas, Helen; Papakostas, Pavlos; Christodoulou, Christos; Bafaloukos, Dimitrios; Razis, Evangelia; Karavasilis, Vasilios; Bamias, Christina; Yannoukakos, Drakoulis; Fountzilas, George

    2017-01-01

    The preservation of pathogenic BRCA1/2 germline mutations in tumor tissues is usually not questioned, while it remains unknown whether these interact with somatic genotypes for patient outcome. Herein we compared germline and tumor genotypes in operable triple-negative breast cancer (TNBC) and evaluated their combined effects on prognosis. We analyzed baseline germline and primary tumor genotype data obtained by Sanger and Next Generation Sequencing in 194 TNBC patients. We also performed multiple tests interrogating the preservation of germline mutations in matched tumors and breast tissue from carriers with available material. Patients had been treated within clinical trials with adjuvant anthracyclines-taxanes based chemotherapy. We identified 50 (26%) germline mutation carriers (78% in BRCA1) and 136 (71%) tumors with somatic mutations (83% in TP53). Tumor mutation patterns differed between carriers and non-carriers (P<0.001); PIK3CA mutations were exclusively present in non-carriers (P=0.007). Germline BRCA1/2 mutations were not detected in matched tumors and breast tissues from 14 out of 33 (42%) evaluable carriers. Microsatellite markers revealed tumor loss of the germline mutant allele in one case only. Tumors that had lost the germline mutation demonstrated a higher incidence of somatic TP53 mutations as compared to tumors with preserved germline mutations (P=0.036). Germline mutation status significantly interacted with tumor TP53 mutations for patient disease-free survival (interaction P=0.026): In non-carriers, tumor TP53 mutations did not affect outcome; In carriers, those with mutated TP53 tumors experienced more relapses compared to those with wild-type TP53 tumors (36% vs. 9% relapse rate, respectively). In conclusion, we show that loss of germline BRCA1/2 mutations is not a rare event in TNBC. This finding, the observed differences in tumor genotypes with respect to germline status and the prognostic interaction between germline BRCA1-related and

  10. The fate of BRCA1-related germline mutations in triple-negative breast tumors.

    PubMed

    Kotoula, Vassiliki; Fostira, Florentia; Papadopoulou, Kyriaki; Apostolou, Paraskevi; Tsolaki, Eleftheria; Lazaridis, Georgios; Manoussou, Kyriaki; Zagouri, Flora; Pectasides, Dimitrios; Vlachos, Ioannis; Tikas, Ioannis; Lakis, Sotiris; Konstantopoulou, Irene; Pentheroudakis, George; Gogas, Helen; Papakostas, Pavlos; Christodoulou, Christos; Bafaloukos, Dimitrios; Razis, Evangelia; Karavasilis, Vasilios; Bamias, Christina; Yannoukakos, Drakoulis; Fountzilas, George

    2017-01-01

    The preservation of pathogenic BRCA1/2 germline mutations in tumor tissues is usually not questioned, while it remains unknown whether these interact with somatic genotypes for patient outcome. Herein we compared germline and tumor genotypes in operable triple-negative breast cancer (TNBC) and evaluated their combined effects on prognosis. We analyzed baseline germline and primary tumor genotype data obtained by Sanger and Next Generation Sequencing in 194 TNBC patients. We also performed multiple tests interrogating the preservation of germline mutations in matched tumors and breast tissue from carriers with available material. Patients had been treated within clinical trials with adjuvant anthracyclines-taxanes based chemotherapy. We identified 50 (26%) germline mutation carriers (78% in BRCA1) and 136 (71%) tumors with somatic mutations (83% in TP53). Tumor mutation patterns differed between carriers and non-carriers (P<0.001); PIK3CA mutations were exclusively present in non-carriers (P=0.007). Germline BRCA1/2 mutations were not detected in matched tumors and breast tissues from 14 out of 33 (42%) evaluable carriers. Microsatellite markers revealed tumor loss of the germline mutant allele in one case only. Tumors that had lost the germline mutation demonstrated a higher incidence of somatic TP53 mutations as compared to tumors with preserved germline mutations (P=0.036). Germline mutation status significantly interacted with tumor TP53 mutations for patient disease-free survival (interaction P=0.026): In non-carriers, tumor TP53 mutations did not affect outcome; In carriers, those with mutated TP53 tumors experienced more relapses compared to those with wild-type TP53 tumors (36% vs. 9% relapse rate, respectively). In conclusion, we show that loss of germline BRCA1/2 mutations is not a rare event in TNBC. This finding, the observed differences in tumor genotypes with respect to germline status and the prognostic interaction between germline BRCA1-related and

  11. Germline and Pluripotent Stem Cells.

    PubMed

    Reik, Wolf; Surani, M Azim

    2015-11-02

    Epigenetic mechanisms play an essential role in the germline and imprinting cycle. Germ cells show extensive epigenetic programming in preparation for the generation of the totipotent state, which in turn leads to the establishment of pluripotent cells in blastocysts. The latter are the cells from which pluripotent embryonic stem cells are derived and maintained in culture. Following blastocyst implantation, postimplantation epiblast cells develop, which give rise to all somatic cells as well as primordial germ cells, the precursors of sperm and eggs. Pluripotent stem cells in culture can be induced to undergo differentiation into somatic cells and germ cells in culture. Understanding the natural cycles of epigenetic reprogramming that occur in the germline will allow the generation of better and more versatile stem cells for both therapeutic and research purposes.

  12. Attenuated familial adenomatous polyposis with desmoids caused by an APC mutation

    PubMed Central

    Ikenoue, Tsuneo; Yamaguchi, Kiyoshi; Komura, Mitsuhiro; Imoto, Seiya; Yamaguchi, Rui; Shimizu, Eigo; Kasuya, Shinichi; Shibuya, Tetsuo; Hatakeyama, Seira; Miyano, Satoru; Furukawa, Yoichi

    2015-01-01

    We present here a case of attenuated familial adenomatous polyposis (AFAP) with a family history of desmoids and thyroid tumors. This patient had no colonic polyps but did have multiple desmoids. Genetic analysis identified a 4-bp deletion in codon 2644 (c.7932_7935delTTAT: p.Tyr2645LysfsX14) of the adenomatous polyposis coli (APC) gene. In cases with limited numbers of colonic polyps and desmoids, AFAP may be caused by a mutation in the 3′ region of APC. PMID:27081525

  13. Attenuated familial adenomatous polyposis with desmoids caused by an APC mutation.

    PubMed

    Ikenoue, Tsuneo; Yamaguchi, Kiyoshi; Komura, Mitsuhiro; Imoto, Seiya; Yamaguchi, Rui; Shimizu, Eigo; Kasuya, Shinichi; Shibuya, Tetsuo; Hatakeyama, Seira; Miyano, Satoru; Furukawa, Yoichi

    2015-01-01

    We present here a case of attenuated familial adenomatous polyposis (AFAP) with a family history of desmoids and thyroid tumors. This patient had no colonic polyps but did have multiple desmoids. Genetic analysis identified a 4-bp deletion in codon 2644 (c.7932_7935delTTAT: p.Tyr2645LysfsX14) of the adenomatous polyposis coli (APC) gene. In cases with limited numbers of colonic polyps and desmoids, AFAP may be caused by a mutation in the 3' region of APC.

  14. Physiological Control of Germline Development

    PubMed Central

    Hubbard, E. Jane Albert; Korta, Dorota Z.; Dalfó, Diana

    2013-01-01

    The intersection between developmental programs and environmental conditions that alter physiology is a growing area of research interest. The C. elegans germ line is emerging as a particularly sensitive and powerful model for these studies. The germ line is subject to environmentally regulated diapause points that allow worms to withstand harsh conditions both prior to and after reproduction commences. It also responds to more subtle changes in physiological conditions. Recent studies demonstrate that different aspects of germ line development are sensitive to environmental and physiological changes and that conserved signaling pathways such as the AMPK, Insulin/IGF, TGFβ, and TOR-S6K, and nuclear hormone receptor pathways mediate this sensitivity. Some of these pathways genetically interact with but appear distinct from previously characterized mechanisms of germline cell fate control such as Notch signaling. Here, we review several aspects of hermaphrodite germline development in the context of “feasting,” “food-limited,” and “fasting” conditions. We also consider connections between lifespan, metabolism and the germ line, and we comment on special considerations for examining germline development under altered environmental and physiological conditions. Finally, we summarize the major outstanding questions in the field. PMID:22872476

  15. Germline Stem Cells: Origin and Destiny

    PubMed Central

    Lehmann, Ruth

    2012-01-01

    Germline stem cells are key to genome transmission to future generations. Over recent years, there have been numerous insights into the regulatory mechanisms that govern both germ cell specification and the maintenance of the germline in adults. Complex regulatory interactions with both the niche and the environment modulate germline stem cell function. This perspective highlights some examples of this regulation to illustrate the diversity and complexity of the mechanisms involved. PMID:22704513

  16. Germline stem cells: origin and destiny.

    PubMed

    Lehmann, Ruth

    2012-06-14

    Germline stem cells are key to genome transmission to future generations. Over recent years, there have been numerous insights into the regulatory mechanisms that govern both germ cell specification and the maintenance of the germline in adults. Complex regulatory interactions with both the niche and the environment modulate germline stem cell function. This perspective highlights some examples of this regulation to illustrate the diversity and complexity of the mechanisms involved. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Missense mutations in MLH1, MSH2, KRAS, and APC genes in colorectal cancer patients in Malaysia.

    PubMed

    Abdul Murad, Nor Azian; Othman, Zulhabri; Khalid, Melati; Abdul Razak, Zuraini; Hussain, Rosniza; Nadesan, Sukumar; Sagap, Ismail; Mohamed Rose, Isa; Wan Ngah, Wan Zurinah; Jamal, Rahman

    2012-11-01

    Colorectal cancer (CRC) is the third most common cancer worldwide with approximately 1 million cases diagnosed annually. In Malaysia, CRC is the second most common cancer in women and ranked first in men. The underlying cause of CRC remains unknown. The aim of this study was to analyze the mutations in genes involved in CRC including MLH1, MSH2, KRAS, and APC genes. A total of 76 patients were recruited. We used the polymerase chain reaction-denaturing high-performance liquid chromatography for the detection of mutations in the mismatch repair (MMR) and APC genes and the PCR single-strand conformation polymorphism for screening of the KRAS gene mutations. We identified 17 types of missense mutations in 38 out of 76 patients in our patients. Nine mutations were identified in the APC gene, five mutations were detected in the KRAS gene, and two mutations were identified in the MSH2 gene. Only one mutation was identified in MLH1. Out of these 17 mutations, eight mutations (47 %) were predicted to be pathogenic. Seven patients were identified with multiple mutations (3: MSH2 and KRAS, 1: KRAS and APC, 1: MLH1 and APC, 2: APC and APC). We have established the PCR-DHPLC and PCR-SSCP for screening of mutations in CRC patients. This study has given a snapshot of the spectrum of mutations in the four genes that were analyzed. Mutation screening in patients and their family members will help in the early detection of CRC and hence will reduce mortality due to CRC.

  18. NUP98 fusion oncoproteins interact with the APC/C(Cdc20) as a pseudosubstrate and prevent mitotic checkpoint complex binding.

    PubMed

    Salsi, Valentina; Fantini, Sebastian; Zappavigna, Vincenzo

    2016-09-01

    NUP98 is a recurrent partner gene in translocations causing acute myeloid leukemias and myelodisplastic syndrome. The expression of NUP98 fusion oncoproteins has been shown to induce mitotic spindle defects and chromosome missegregation, which correlate with the capability of NUP98 fusions to cause mitotic checkpoint attenuation. We show that NUP98 oncoproteins physically interact with the APC/C(Cdc20) in the absence of the NUP98 partner protein RAE1, and prevent the binding of the mitotic checkpoint complex to the APC/C(Cdc20). NUP98 oncoproteins require the GLEBS-like domain present in their NUP98 moiety to bind the APC/C(Cdc20). We found that NUP98 wild-type is a substrate of APC/C(Cdc20) prior to mitotic entry, and that its binding to APC/C(Cdc20) is controlled via phosphorylation of a PEST sequence located within its C-terminal portion. We identify S606, within the PEST sequence, as a key target site, whose phosphorylation modulates the capability of NUP98 to interact with APC/C(Cdc20). We finally provide evidence for an involvement of the peptidyl-prolyl isomerase PIN1 in modulating the possible conformational changes within NUP98 that lead to its dissociation from the APC/C(Cdc20) during mitosis. Our results provide novel insight into the mechanisms underlying the aberrant capability of NUP98 oncoproteins to interact with APC/C(Cdc20) and to interfere with its function.

  19. A relay mechanism between EB1 and APC facilitate STIM1 puncta assembly at endoplasmic reticulum-plasma membrane junctions.

    PubMed

    Asanov, Alexander; Sherry, Ryan; Sampieri, Alicia; Vaca, Luis

    2013-09-01

    The assembly of STIM1 protein puncta near endoplasmic reticulum-plasma membrane (ER-PM) junctions is required for optimal activation of store-operated channels (SOC). The mechanisms controlling the translocation of STIM1 puncta to ER-PM junctions remain largely unknown. In the present study, we have explored the role of the microtubule binding protein adenomatous polyposis coli (APC), on STIM1 puncta and store-operated calcium entry (SOCE). APC-depleted cells showed reduced STIM1 puncta near ER-PM junctions, instead puncta is found at the ER surrounding the cell nucleus. Reduced STIM1 puncta near ER-PM junctions in APC-depleted cells correlates with a strong inhibition of SOCE and diminished Orai whole-cell currents. Immunoprecipitation and confocal microscopy co-localization studies indicate that, upon depletion of the ER, STIM1 dissociates from EB1 and associates to APC. Deletion analysis identified an APC-binding domain in the carboxyl terminus of STIM1 (STIM1 650-685). These results together position APC as an important element in facilitating the translocation of STIM1 puncta near ER-PM junctions, which in turn is required for efficient SOCE and Orai activation upon depletion of the ER.

  20. Specific immunotherapy by genetically engineered APCs: the "guided missile" strategy.

    PubMed

    Wu, B; Wu, J M; Miagkov, A; Adams, R N; Levitsky, H I; Drachman, D B

    2001-04-01

    We tested the hypothesis that APCs genetically engineered to present an Ag and to express Fas ligand (FasL) simultaneously can target and eliminate Ag-specific T cells. Transgenic T cells specific for influenza hemagglutinin (HA) were used as targets. We prepared recombinant vaccinia virus vectors (VVV) to transfer the gene constructs individually or simultaneously into APCs. We prevented unwanted viral replication by attenuating the VVVs with psoralen-UV light treatment. For presentation of the HA Ag, APCs were transduced with cDNA for HA flanked by sequences of the lysosome-associated membrane protein that direct efficient processing and presentation of the Ag by APCs. As a "warhead" for the APCs, we transduced them with the gene for FasL, which induces apoptosis of Fas-expressing activated T cells. To protect the transduced APCs from self-destruction by FasL, we transferred cDNA for a truncated form of Fas-associated death domain, which inhibits Fas-mediated cell death. Our results show that the engineered APCs effectively expressed the genes of interest. APCs transduced with VVV carrying all three gene constructs specifically killed HA-transgenic T cells in culture. Coculture with T cells specific for an unrelated Ag (OVA) had no significant effect. Our in vitro findings show that APCs can be genetically engineered to target and kill Ag-specific T cells and represent a promising novel strategy for the specific treatment of autoimmune diseases.

  1. Severe polyposis in Apc1322T mice is associated with submaximal Wnt signalling and increased expression of the stem cell marker Lgr5

    PubMed Central

    Segditsas, Stefania; Deheragoda, Maesha; Pollard, Patrick; Jeffery, Rosemary; Nye, Emma; Lockstone, Helen; Davis, Hayley; Clark, Susan; Stamp, Gordon; Poulsom, Richard; Wright, Nicholas; Tomlinson, Ian

    2010-01-01

    Background and aims Adenomatous polyposis coli (APC) is a tumour suppressor gene mutated in the germline of patients with familial adenomatous polyposis (FAP) and somatically in most colorectal cancers. APC mutations impair β-catenin degradation, resulting in increased Wnt signalling. The most frequent APC mutation is a codon 1309 truncation that is associated with severe FAP. A previous study compared two mouse models of intestinal tumorigenesis, ApcR850X (Min) and Apc1322T (1322T), the latter a model of human codon 1309 changes. 1322T mice had more severe polyposis but, surprisingly, these tumours had lower levels of nuclear β-catenin than Min tumours. The consequences of these different β-catenin levels were investigated. Methods Enterocytes were isolated from 1322T and Min tumours by microdissection and gene expression profiling was performed. Differentially expressed Wnt targets and other stem cell markers were validated using quantitative PCR, in situ hybridisation and immunohistochemistry. Results As expected, lower nuclear β-catenin levels in 1322T lesions were associated with generally lower levels of Wnt target expression. However, expression of the Wnt target and stem cell marker Lgr5 was significantly higher in 1322T tumours than in Min tumours. Other stem cell markers (Musashi1, Bmi1 and the Wnt target Cd44) were also at higher levels in 1322T tumours. In addition, expression of the Bmp antagonist Gremlin1 was higher in 1322T tumours, together with lower Bmp2 and Bmp4 expression. Conclusions The severe phenotype caused by truncation of Apc at codon 1322 is associated with an increased number of stem cells. Thus, a submaximal level of Wnt signalling favours the stem cell phenotype and this may promote tumorigenesis. A level of Wnt signalling exists that is too high for optimal tumour growth. PMID:20926645

  2. Flow cytometry sorting of nuclei enables the first global characterization of Paramecium germline DNA and transposable elements.

    PubMed

    Guérin, Frédéric; Arnaiz, Olivier; Boggetto, Nicole; Denby Wilkes, Cyril; Meyer, Eric; Sperling, Linda; Duharcourt, Sandra

    2017-04-26

    DNA elimination is developmentally programmed in a wide variety of eukaryotes, including unicellular ciliates, and leads to the generation of distinct germline and somatic genomes. The ciliate Paramecium tetraurelia harbors two types of nuclei with different functions and genome structures. The transcriptionally inactive micronucleus contains the complete germline genome, while the somatic macronucleus contains a reduced genome streamlined for gene expression. During development of the somatic macronucleus, the germline genome undergoes massive and reproducible DNA elimination events. Availability of both the somatic and germline genomes is essential to examine the genome changes that occur during programmed DNA elimination and ultimately decipher the mechanisms underlying the specific removal of germline-limited sequences. We developed a novel experimental approach that uses flow cell imaging and flow cytometry to sort subpopulations of nuclei to high purity. We sorted vegetative micronuclei and macronuclei during development of P. tetraurelia. We validated the method by flow cell imaging and by high throughput DNA sequencing. Our work establishes the proof of principle that developing somatic macronuclei can be sorted from a complex biological sample to high purity based on their size, shape and DNA content. This method enabled us to sequence, for the first time, the germline DNA from pure micronuclei and to identify novel transposable elements. Sequencing the germline DNA confirms that the Pgm domesticated transposase is required for the excision of all ~45,000 Internal Eliminated Sequences. Comparison of the germline DNA and unrearranged DNA obtained from PGM-silenced cells reveals that the latter does not provide a faithful representation of the germline genome. We developed a flow cytometry-based method to purify P. tetraurelia nuclei to high purity and provided quality control with flow cell imaging and high throughput DNA sequencing. We identified 61

  3. Presence of a TA haplotype in the APC gene containing the common 1822 polymorphism and colorectal adenoma.

    PubMed

    Egan, Jan B; Jacobs, Elizabeth T; Martínez, María Elena; Gerner, Eugene W; Jurutka, Peter W; Thompson, Patricia A

    2008-07-15

    Acquired or inherited mutations in the adenomatous polyposis coli (APC) tumor suppressor gene are causally linked to colorectal cancer. Given the significance of APC in colorectal cancer, we investigated the association between common single-nucleotide polymorphisms (SNP) in the APC gene and the odds of developing metachronous colorectal adenomas as a surrogate measure of colorectal cancer risk. Coding SNPs at codons 486, 1678, 1822, 1960, and 2502 were analyzed in a total of 1,399 subjects who participated in two randomized clinical trials for the prevention of colorectal adenomas. No association was found for any single SNP and the odds of metachronous adenoma. In contrast, a TA haplotype (codons 486 and 1822) was associated with a statistically significant 27% and 26% reduction in the odds of any and nonadvanced metachronous adenoma after adjustment for baseline adenoma characteristics [odds ratio (OR), 0.73; 95% confidence interval (95% CI), 0.59-0.91 and OR, 0.74; 95% CI, 0.57-0.94], respectively. No significant reduction in odds was observed for advanced metachronous lesions. Diplotype analysis revealed a strong gene dose effect with carriers of two alleles containing TT-AA (codons 486 and 1822, respectively) having an 89% lower odds for advanced metachronous adenomas (OR, 0.11; 95% CI, 0.01-0.80) when compared with the common CC-AA diplotype (codons 486 and 1822, respectively). Our findings support an important role for germ-line allele sequence in the APC gene and individual risk of metachronous adenomatous polyps.

  4. Germline mosaicism at the fragile X locus

    SciTech Connect

    Papp, A.C.; Snyder, P.J.; Sedra, M.S.

    1994-09-01

    The fragile X full mutation, which is associated with the phenotypic expression of the disorder, is characterized by an expansion of CGG repeat and hypermethylation of the CpG island adjacent to the FMR1 gene. New mutations leading to amplification of the CGG repeat have not been reported. We have identified a fragile X syndrome pedigree where the disorder is associated with a molecular deletion. The deletion was present in the DNA of two affected sons but was absent in the mother`s somatic cell (lymphocyte) DNA. This was confirmed by dosage analysis of the Southern blot using StB12-3 and an additional probe against the dystrophin gene and by PCR analysis of DXS548 alleles. The results are consistent with the deletion arising as a postzygotic event in the mother, who therefore is germinally mosaic. The case reported here clearly demonstrates that FMR1 deletions, unlike the expansions, are not always inherited and the finding of heterozygosity or normal dosage from lymphocyte DNA in the mother of a deletion case does not necessarily rule out the possibility of having a second affected child. The deletion of FMR1 gene may be responsible for a small but significant number of fragile X cases. Therefore, it is imperative that those involved in genetic counseling recognize this diagnostic pitfall. Since it depends upon the size of the mutant clone in the mosaic mother, the exact recurrence risk in germline carriers is unknown. However, prenatal and carrier testing should be performed independently of the outcome of the mother. Furthermore, it is possible that the deletion may not be restricted to the germline, and therefore the mother may actually be a somatic mosaic.

  5. Investigating polymorphisms by bioinformatics is a potential cost-effective method to screen for germline mutations in Chinese familial adenomatous polyposis patients

    PubMed Central

    YANG, JUN; LIU, WEI QING; LI, WEN LIANG; CHEN, CHENG; ZHU, ZHU; HONG, MIN; WANG, ZHI QIANG; DONG, JIAN

    2016-01-01

    The aim of this study was to investigate germline mutations of the APC, MUTYH and AXIN2 genes in Chinese patients with familial adenomatous polyposis (FAP), and further assess the value of bioinformatics in screening the pathogenic changes predisposing to FAP. APC genes from 11 unrelated FAP patients in Yunnan province in China were firstly examined by exon-specific DNA sequencing. For samples without already known pathogenic changes predisposing to FAP in the APC gene, whole-gene sequencing of MUTYH and AXIN2 was performed. Mutational analysis of each gene was performed by bioinformatics. Eleven different types of APC polymorphisms were observed in the cohort of families analyzed. Of these polymorphisms, four were missense substitutions (V1822D, V1173G, P1760H and K2057), one was a nonsense substitution (S1196X), and six were silent substitutions (Y486Y, T449T, T1493T, G1678G, S1756S and P1960P). One missense mutation (Q335H) and two intronic substitutions (c.264+11G>A and c.420+35A>G) were detected in the MUTYH gene, and four synonymous mutations (I144I, P455P, P462P and L688L) and three intonic mutations (c.1060–77G>T, c.1060–287A>G and c.1060–282 A>G) of the AXIN2 gene were observed. In addition to the already reported pathogenic mutations, by using function assessment tools and databases, the synonymous substitutions observed in the APC gene of our samples were predicted to affect splicing regulation in the translation of mRNA, while the missense mutations observed in the APC gene and MUTYH gene were predicted to be disease-related polymorphisms; however, no functional effect of the mutations was observed in the AXIN2 gene. Comprehensive screening for germline mutations in APC, MUTYH and AXIN2 genes followed by prediction of pathogenicity using bioinformatic tools contributes to a cost-effective way of screening germline mutations in Chinese familial adenomatous polyposis patients. PMID:27347161

  6. Evaluating the organizational effectiveness of APC implementation efforts.

    PubMed

    Patel, Rajan

    2002-06-01

    To optimize revenue under the Medicare outpatient prospective payment system's new coding-based ambulatory payment classifications (APCs), healthcare providers need to ensure several key steps are taken at the organizational level. Individuals who manage coding need to identify areas of overlap and adjust billing systems to reflect changes under the system. Billing managers should develop practices and protocols that provide detailed reviews of claims, implement a formal denial management program, track reasons for denials, and communicate denial information with their staffs. Proper evaluation of financial practices also is important. Financial managers need to develop formal ways to monitor financial performance consistently and on an ongoing basis and ensure the hospital is generating sufficient volume and keeping service costs in line with payments.

  7. WD40 domain of Apc1 is critical for the coactivator-induced allosteric transition that stimulates APC/C catalytic activity

    PubMed Central

    Li, Qiuhong; Chang, Leifu; Aibara, Shintaro; Yang, Jing; Zhang, Ziguo; Barford, David

    2016-01-01

    The anaphase-promoting complex/cyclosome (APC/C) is a large multimeric cullin–RING E3 ubiquitin ligase that orchestrates cell-cycle progression by targeting cell-cycle regulatory proteins for destruction via the ubiquitin proteasome system. The APC/C assembly comprises two scaffolding subcomplexes: the platform and the TPR lobe that together coordinate the juxtaposition of the catalytic and substrate-recognition modules. The platform comprises APC/C subunits Apc1, Apc4, Apc5, and Apc15. Although the role of Apc1 as an APC/C scaffolding subunit has been characterized, its specific functions in contributing toward APC/C catalytic activity are not fully understood. Here, we report the crystal structure of the N-terminal domain of human Apc1 (Apc1N) determined at 2.2-Å resolution and provide an atomic-resolution description of the architecture of its WD40 (WD40 repeat) domain (Apc1WD40). To understand how Apc1WD40 contributes to APC/C activity, a mutant form of the APC/C with Apc1WD40 deleted was generated and evaluated biochemically and structurally. We found that the deletion of Apc1WD40 abolished the UbcH10-dependent ubiquitination of APC/C substrates without impairing the Ube2S-dependent ubiquitin chain elongation activity. A cryo-EM structure of an APC/C–Cdh1 complex with Apc1WD40 deleted showed that the mutant APC/C is locked into an inactive conformation in which the UbcH10-binding site of the catalytic module is inaccessible. Additionally, an EM density for Apc15 is not visible. Our data show that Apc1WD40 is required to mediate the coactivator-induced conformational change of the APC/C that is responsible for stimulating APC/C catalytic activity by promoting UbcH10 binding. In contrast, Ube2S activity toward APC/C substrates is not dependent on the initiation-competent conformation of the APC/C. PMID:27601667

  8. Novel germline mutations in the calreticulin gene: implications for the diagnosis of myeloproliferative neoplasms.

    PubMed

    Szuber, Natasha; Lamontagne, Bruno; Busque, Lambert

    2016-07-27

    Mutations in the calreticulin (CALR) gene are found in the majority of Janus kinase 2-negative myeloproliferative neoplasms MPN and, thus far, have exclusively been reported as acquired, somatic mutations. We assessed the mutational status of exon 9 of the CALR gene in 2000 blood samples submitted to our centre and identified 12 subjects (0.6%) harbouring distinctive CALR mutations, all with an allelic frequency of 50% and all involving indels occurring as multiples of 3 bp. Buccal cell samples obtained from these patients confirmed the germline nature of the mutations. Importantly, these germline mutations were not diagnostic of MPN. We thus report for the first time the identification and confirmation of germline mutations in CALR distinct from those somatic mutations that define classical MPN. The finding of a non-standard CALR mutation with an allelic frequency of 50% should raise suspicion of the possibility of a germline CALR mutation and these cases investigated further.

  9. GPCRs Direct Germline Development and Somatic Gonad Function in Planarians.

    PubMed

    Saberi, Amir; Jamal, Ayana; Beets, Isabel; Schoofs, Liliane; Newmark, Phillip A

    2016-05-01

    Planarians display remarkable plasticity in maintenance of their germline, with the ability to develop or dismantle reproductive tissues in response to systemic and environmental cues. Here, we investigated the role of G protein-coupled receptors (GPCRs) in this dynamic germline regulation. By genome-enabled receptor mining, we identified 566 putative planarian GPCRs and classified them into conserved and phylum-specific subfamilies. We performed a functional screen to identify NPYR-1 as the cognate receptor for NPY-8, a neuropeptide required for sexual maturation and germ cell differentiation. Similar to NPY-8, knockdown of this receptor results in loss of differentiated germ cells and sexual maturity. NPYR-1 is expressed in neuroendocrine cells of the central nervous system and can be activated specifically by NPY-8 in cell-based assays. Additionally, we screened the complement of GPCRs with expression enriched in sexually reproducing planarians, and identified an orphan chemoreceptor family member, ophis, that controls differentiation of germline stem cells (GSCs). ophis is expressed in somatic cells of male and female gonads, as well as in accessory reproductive tissues. We have previously shown that somatic gonadal cells are required for male GSC specification and maintenance in planarians. However, ophis is not essential for GSC specification or maintenance and, therefore, defines a secondary role for planarian gonadal niche cells in promoting GSC differentiation. Our studies uncover the complement of planarian GPCRs and reveal previously unappreciated roles for these receptors in systemic and local (i.e., niche) regulation of germ cell development.

  10. GPCRs Direct Germline Development and Somatic Gonad Function in Planarians

    PubMed Central

    Saberi, Amir; Beets, Isabel; Schoofs, Liliane; Newmark, Phillip A.

    2016-01-01

    Planarians display remarkable plasticity in maintenance of their germline, with the ability to develop or dismantle reproductive tissues in response to systemic and environmental cues. Here, we investigated the role of G protein-coupled receptors (GPCRs) in this dynamic germline regulation. By genome-enabled receptor mining, we identified 566 putative planarian GPCRs and classified them into conserved and phylum-specific subfamilies. We performed a functional screen to identify NPYR-1 as the cognate receptor for NPY-8, a neuropeptide required for sexual maturation and germ cell differentiation. Similar to NPY-8, knockdown of this receptor results in loss of differentiated germ cells and sexual maturity. NPYR-1 is expressed in neuroendocrine cells of the central nervous system and can be activated specifically by NPY-8 in cell-based assays. Additionally, we screened the complement of GPCRs with expression enriched in sexually reproducing planarians, and identified an orphan chemoreceptor family member, ophis, that controls differentiation of germline stem cells (GSCs). ophis is expressed in somatic cells of male and female gonads, as well as in accessory reproductive tissues. We have previously shown that somatic gonadal cells are required for male GSC specification and maintenance in planarians. However, ophis is not essential for GSC specification or maintenance and, therefore, defines a secondary role for planarian gonadal niche cells in promoting GSC differentiation. Our studies uncover the complement of planarian GPCRs and reveal previously unappreciated roles for these receptors in systemic and local (i.e., niche) regulation of germ cell development. PMID:27163480

  11. Single nucleotide polymorphisms of the APC gene and colorectal cancer risk: a case-control study in Taiwan

    PubMed Central

    Chen, Shee-Ping; Tsai, Shih-Tzu; Jao, Shu-Wen; Huang, Yen-Lun; Chao, Yu-Chen; Chen, Yi-Lin; Wu, Chang-Chieh; Lin, Shinn-Zong; Harn, Horng-Jyh

    2006-01-01

    Background Colorectal cancer (CRC), which has become especially prevalent in developed countries, is currently the third highest cause of cancer mortality in Taiwan. Mutation of the adenomatous polyposis coli (APC) gene, a tumour suppressor, is thought to be an early event in colorectal tumourigenesis. To date, however, no large-scale screening for APC gene variants in Chinese subjects has been performed. The present study was undertaken to identify APC gene variants that are significantly associated with the occurrence of CRC in Taiwanese subjects. Methods In order to compare the genotype distribution of variant sites, the full-length APC genes of 74 healthy individuals and 80 CRC patients were sequenced. Results Among the 154 Taiwanese subjects examined in this study, three new mutations, but no previously reported mutations, were found. One deletion at codon 460 leading to a frameshift and two missense mutations resulting in p.V1125A and p.S1126R substitutions were identified. Additionally, three high risk genotypes associated with three single nucleotide polymorphisms and one low risk genotype at codon 1822 were identified. Conclusion The findings of this case-control study are consistent with the proposal that Taiwanese subjects differ from other subjects with respect to phenotypic presentation of APC and CRC risk. PMID:16569251

  12. Breast cancer risk and clinical implications for germline PTEN mutation carriers.

    PubMed

    Ngeow, Joanne; Sesock, Kaitlin; Eng, Charis

    2017-08-01

    PTEN Hamartoma Tumor syndrome (PHTS) encompasses a clinical spectrum of heritable disorders including Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome, and Proteus and Proteus-like syndrome that are associated with germline mutations in the PTEN tumor suppressor gene. Breast cancer risk estimates (67-85 %) for women with germline PTEN mutations are similar to those quoted for patients with germline mutations in the BRCA1/2 genes. With PTEN on several germline gene testing panels, finding PTEN mutations and variants have increased exponentially. PHTS can be differentiated from other hereditary cancer syndromes including Hereditary Breast Ovarian Cancer syndrome, Lynch syndrome, and hamartomatous polyposis syndromes based on personal as well as family history. However, many of the benign features of CS are common in the general population, making the diagnosis of CS challenging. Breast cancer patients with an identified germline PTEN mutation are at increased risk of endometrial, thyroid, renal, and colorectal cancers as well as a second breast cancer. Increased screening for the various component cancers as well as predictive testing in first-degree relatives is recommended. Prophylactic mastectomy may be considered especially if breast tissue is dense or if repeated breast biopsies have been necessary. Management of women with breast cancer suspected of CS who test negative for germline PTEN mutations should be managed as per a mutation carrier if she meets CS diagnostic criteria, and should be offered enrollment in research to identify other predisposition genes.

  13. Realtime Implementation of the APC/SQ and LPC-10 Speech Coding Algorithms.

    DTIC Science & Technology

    1982-06-01

    KEY WORDS (Continue on reverse side if necessary ad Identify by block number) Speech coding, APC/SQ, LPC-IO, 9.6 kb/s speech transmission, 2.4 kb/s...coding, digital voice terminal, real-time speech coder, \\ array processor 0. ABSTRACT (Continue on reverse side If neceeemy end Identify by block... machine , the CSPU. The control strategy for allowing each module as much flexibility as possible results in a structure that executes a module only if

  14. Adenomatous polyposis coli (APC) membrane recruitment 3, a member of the APC membrane recruitment family of APC-binding proteins, is a positive regulator of Wnt-β-catenin signalling.

    PubMed

    Brauburger, Katharina; Akyildiz, Senem; Ruppert, Jan G; Graeb, Michael; Bernkopf, Dominic B; Hadjihannas, Michel V; Behrens, Jürgen

    2014-02-01

    The adenomatous polyposis coli (APC) membrane recruitment (Amer) family proteins Amer1/Wilms tumour gene on the X chromosome and Amer2 are binding partners of the APC tumour suppressor protein, and act as negative regulators in the Wnt signalling cascade. So far, nothing has been known about the third member of the family, Amer3. Here we show that Amer3 binds to the armadillo repeat domain of APC, similarly to Amer1 and Amer2. Amer3 also binds to the Wnt pathway regulator conductin/axin2. Furthermore, we identified Amer1 as binding partner of Amer3. Whereas Amer1 and Amer2 are linked to the plasma membrane by an N-terminal membrane localization domain, Amer3 lacks this domain. Amer3 localizes to the cytoplasm and nucleus of epithelial cells, and this is dependent on specific nuclear import and export sequences. Functionally, exogenous Amer3 enhances the expression of a β-catenin/T-cell factor-dependent reporter gene, and knockdown of endogenous Amer3 reduces Wnt target gene expression in colorectal cancer cells. Thus, Amer3 acts as an activator of Wnt signalling, in contrast to Amer1 and Amer2, which are inhibitors, suggesting a nonredundant role of Amer proteins in the regulation of this pathway. Our data, together with those of previous studies, provide a comprehensive picture of similarities and differences within the Amer protein family. © 2013 FEBS.

  15. DRO1 inactivation drives colorectal carcinogenesis in ApcMin/+ mice.

    PubMed

    Grill, Jessica I; Neumann, Jens; Herbst, Andreas; Hiltwein, Felix; Ofner, Andrea; Marschall, Maximilian K; Wolf, Eckhard; Kirchner, Thomas; Göke, Burkhard; Schneider, Marlon R; Kolligs, Frank T

    2014-11-01

    Colorectal cancer develops from adenomatous precursor lesions by a multistep process that involves several independent mutational events in oncogenes and tumor suppressor genes. Inactivation of the adenomatous polyposis coli (APC) tumor suppressor gene is an early event and a prerequisite for the development of human colorectal adenoma. Previous in vitro studies identified DRO1 (CCDC80) to be a putative tumor suppressor gene that is negatively regulated in colorectal cancers and downregulated upon neoplastic transformation of epithelial cells. To investigate the in vivo role of DRO1 in colorectal carcinogenesis, a constitutive DRO1 knockout mouse model was generated. Disruption of DRO1 did not result in spontaneous intestinal tumor formation, consistent with the notion that DRO1 might have a role in suppressing the development of colon tumors in Apc(Min) (/+) mice, a widely used model for studying the role of APC in intestinal tumorigenesis that is hampered by the fact that mice predominantly develop adenomas in the small intestine and not in the colon. Here, deletion of DRO1 in Apc(Min) (/+) mice results in earlier death, a dramatically increased colonic tumor burden, and frequent development of colorectal carcinoma. Furthermore, enhanced phosphorylation of ERK1/2 is observed in colon epithelium and tumors from DRO1 knockout mice. Thus, this study reveals that inactivation of DRO1 is required for colorectal carcinogenesis in the Apc(Min) (/+) mouse and establishes a new mouse model for the study of colorectal cancer. This report characterizes a new mouse model for the study of colorectal cancer and establishes DRO1 (CCDC80) as a tumor suppressor via a mechanism involving ERK phosphorylation. ©2014 American Association for Cancer Research.

  16. A novel mutation of adenomatous polyposis coli (APC) gene results in the formation of supernumerary teeth.

    PubMed

    Yu, Fang; Cai, Wenping; Jiang, Beizhan; Xu, Laijun; Liu, Shangfeng; Zhao, Shouliang

    2017-08-07

    Supernumerary teeth are teeth that are present in addition to normal teeth. Although several hypotheses and some molecular signalling pathways explain the formation of supernumerary teeth, but their exact disease pathogenesis is unknown. To study the molecular mechanisms of supernumerary tooth-related syndrome (Gardner syndrome), a deeper understanding of the aetiology of supernumerary teeth and the associated syndrome is needed, with the goal of inhibiting disease inheritance via prenatal diagnosis. We recruited a Chinese family with Gardner syndrome. Haematoxylin and eosin staining of supernumerary teeth and colonic polyp lesion biopsies revealed that these patients exhibited significant pathological characteristics. APC gene mutations were detected by PCR and direct sequencing. We revealed the pathological pathway involved in human supernumerary tooth development and the mouse tooth germ development expression profile by RNA sequencing (RNA-seq). Sequencing analysis revealed that an APC gene mutation in exon 15, namely 4292-4293-Del GA, caused Gardner syndrome in this family. This mutation not only initiated the various manifestations typical of Gardner syndrome but also resulted in odontoma and supernumerary teeth in this case. Furthermore, RNA-seq analysis of human supernumerary teeth suggests that the APC gene is the key gene involved in the development of supernumerary teeth in humans. The mouse tooth germ development expression profile shows that the APC gene plays an important role in tooth germ development. We identified a new mutation in the APC gene that results in supernumerary teeth in association with Gardner syndrome. This information may shed light on the molecular pathogenesis of supernumerary teeth. Gene-based diagnosis and gene therapy for supernumerary teeth may become available in the future, and our study provides a high-resolution reference for treating other syndromes associated with supernumerary teeth. © 2017 The Authors. Journal of

  17. High promoter methylation levels of APC predict poor prognosis in sextant biopsies from prostate cancer patients.

    PubMed

    Henrique, Rui; Ribeiro, Franclim R; Fonseca, Daniel; Hoque, Mohammad O; Carvalho, André L; Costa, Vera L; Pinto, Mafalda; Oliveira, Jorge; Teixeira, Manuel R; Sidransky, David; Jerónimo, Carmen

    2007-10-15

    Prostate cancer is a highly prevalent malignancy and constitutes a major cause of cancer-related morbidity and mortality. Owing to the limitations of current clinical, serologic, and pathologic parameters in predicting disease progression, we sought to investigate the prognostic value of promoter methylation of a small panel of genes by quantitative methylation-specific PCR (QMSP) in prostate biopsies. Promoter methylation levels of APC, CCND2, GSTP1, RARB2, and RASSF1A were determined by QMSP in a prospective series of 83 prostate cancer patients submitted to sextant biopsy. Clinicopathologic data [age, serum prostate-specific antigen (PSA), stage, and Gleason score] and time to progression and/or death from prostate cancer were correlated with methylation findings. Log-rank test and Cox regression model were used to identify which epigenetic markers were independent predictors of prognosis. At a median follow-up time of 45 months, 15 (18%) patients died from prostate cancer, and 37 (45%) patients had recurrent disease. In univariate analysis, stage and hypermethylation of APC were significantly associated with worse disease-specific survival, whereas stage, Gleason score, high diagnostic serum PSA levels, and hypermethylation of APC, GSTP1, and RASSF1A were significantly associated with poor disease-free survival. However, in the final multivariate analysis, only clinical stage and high methylation of APC were significantly and independently associated with unfavorable prognosis, i.e., decreased disease-free and disease-specific survival. High-level APC promoter methylation is an independent predictor of poor prognosis in prostate biopsy samples and might provide relevant prognostic information for patient management.

  18. How to Bond Zirconia: The APC Concept.

    PubMed

    Blatz, Markus B; Alvarez, Marcela; Sawyer, Kimiyo; Brindis, Marco

    2016-10-01

    Zirconia has become one of the most popular materials in dentistry. New high-translucent zirconia ceramics have favorable optical properties and can be applied as monolithic full-contour restorations in various clinical indications for posterior and anterior teeth. However, having reliable cementation protocols is fundamental for clinical success of indirect ceramic dental restorations, including those made from zirconia materials. Resin bonding supports ceramic restorations and is necessary for onlays, laminate veneers, and resinbonded fixed dental prostheses. The APC zirconia-bonding concept is based on decades of research on how to achieve high and long-term durable bond strengths to high-strength ceramics. It includes three practical steps: (A) airparticle abrasion, (P) zirconia primer, and (C) adhesive composite resin. This article discusses the history and development of high-translucent zirconia and explains the necessity for proper cementation. The rationale and science behind a simplified zirconia-bonding concept is explained and illustrated with a clinical case presentation.

  19. Targeted apc;twist double-mutant mice: a new model of spontaneous osteosarcoma that mimics the human disease.

    PubMed

    Entz-Werlé, Natacha; Choquet, Philippe; Neuville, Agnès; Kuchler-Bopp, Sabine; Clauss, François; Danse, Jean-Marc; Simo-Noumbissie, Pauline; Guérin, Eric; Gaub, Marie-Pierre; Freund, Jean-Noel; Boehm, Nelly; Constantinesco, André; Lutz, Patrick; Guenot, Dominique; Perrin-Schmitt, Fabienne

    2010-12-01

    TWIST and adenomatosis polyposis coli (APC) are critical signaling factors in normal bone development. In previous studies examining a homogeneously treated cohort of pediatric osteosarcoma patients, we reported the frequent and concurrent loss of both TWIST and APC genes. On these bases, we created a related animal model to further explore the oncogenic cooperation between these two genes. We performed intercrosses between twist-null/+ and Apc1638N/+ mice and studied their progeny. The Apc1638N/+;twistnull/+ mice developed bone abnormalities observed by macroscopic skeletal analyses and in vivo imaging. Complementary histologic, cellular, and molecular analyses were used to characterize the identified bone tumors, including cell culture and immunofluorescence of bone differentiation markers. Spontaneous localized malignant bone tumors were frequently identified in Apc1638N/+;twist-null/+ mice by in vivo imaging evaluation and histologic analyses. These tumors possessed several features similar to those observed in human localized osteosarcomas. In particular, the murine tumors presented with fibroblastic, chondroblastic, and osteoblastic osteosarcoma histologies, as well as mixtures of these subtypes. In addition, cellular analyses and bone differentiation markers detected by immunofluorescence on tumor sections reproduced most murine and human osteosarcoma characteristics. For example, the early bone differentiation marker Runx2, interacting physically with hypophosphorylated pRb, was undetectable in these murine osteosarcomas, whereas phosphorylated retinoblastoma was abundant in the osteoblastic and chondroblastic tumor subtypes. These characteristics, similar to those observed in human osteosarcomas, indicated that our animal model may be a powerful tool to further understand the development of localized osteosarcoma.

  20. Dietary, lifestyle and clinicopathological factors associated with APC mutations and promoter methylation in colorectal cancers from the EPIC-Norfolk study.

    PubMed

    Gay, Laura J; Mitrou, Panagiota N; Keen, Jennifer; Bowman, Richard; Naguib, Adam; Cooke, James; Kuhnle, Gunter G; Burns, Philip A; Luben, Robert; Lentjes, Marleen; Khaw, Kay-Tee; Ball, Richard Y; Ibrahim, Ashraf Ek; Arends, Mark J

    2012-11-01

    The tumour suppressor APC is the most commonly altered gene in colorectal cancer (CRC). Genetic and epigenetic alterations of APC may therefore be associated with dietary and lifestyle risk factors for CRC. Analysis of APC mutations in the extended mutation cluster region (codons 1276-1556) and APC promoter 1A methylation was performed on 185 archival CRC samples collected from participants of the European Prospective Investigation into Cancer (EPIC)-Norfolk study, with the aim of relating these to high-quality seven-day dietary and lifestyle data collected prospectively. Truncating APC mutations (APC(+) ) and promoter 1A methylation (PM(+) ) were identified in 43% and 23% of CRCs analysed, respectively. Distal CRCs were more likely than proximal CRCs to be APC(+) or PM(+) (p = 0.04). APC(+) CRCs were more likely to be moderately/well differentiated and microsatellite stable than APC(-) CRCs (p = 0.05 and 0.03). APC(+) CRC cases consumed more alcohol than their counterparts (p = 0.01) and PM(+) CRC cases consumed lower levels of folate and fibre (p = 0.01 and 0.004). APC(+) or PM(+) CRC cases consumed higher levels of processed meat and iron from red meat and red meat products (p = 0.007 and 0.006). Specifically, CRC cases harbouring GC-to-AT transition mutations consumed higher levels of processed meat (35 versus 24 g/day, p = 0.04) and iron from red meat and red meat products (0.8 versus 0.6 mg/day, p = 0.05). In a logistic regression model adjusted for age, sex and cigarette-smoking status, each 19 g/day (1SD) increment increase in processed meat consumption was associated with cases with GC-to-AT mutations (OR 1.68, 95% CI 1.03-2.75). In conclusion, APC(+) and PM(+) CRCs may be influenced by diet and GC-to-AT mutations in APC are associated with processed meat consumption, suggesting a mechanistic link with dietary alkylating agents, such as N-nitroso compounds.

  1. Phosphorylation of RNA polymerase II is independent of P-TEFb in the C. elegans germline

    PubMed Central

    Bowman, Elizabeth Anne; Bowman, Christopher Ray; Ahn, Jeong H.; Kelly, William G.

    2013-01-01

    RNA polymerase II (Pol II) elongation in metazoans is thought to require phosphorylation of serine 2 (Ser2-P) of the Pol II C-terminal domain (CTD) by the P-TEFb complex, CDK-9/cyclin T. Another Ser2 kinase complex, CDK-12/cyclin K, which requires upstream CDK-9 activity has been identified in Drosophila and human cells. We show that regulation of Ser2-P in C. elegans soma is similar to other metazoan systems, but Ser2-P in the germline is independent of CDK-9, and largely requires only CDK-12. The observed differences are not due to differential tissue expression as both kinases and their cyclin partners are ubiquitously expressed. Surprisingly, loss of CDK-9 from germ cells has little effect on Ser2-P, yet CDK-9 is essential for germline development. By contrast, loss of CDK-12 and Ser2-P specifically from germ cells has little impact on germline development or function, although significant loss of co-transcriptional H3K36 trimethylation is observed. These results show a reduced requirement for Pol II Ser2-P in germline development and suggest that generating Ser2-P is not the essential role of CDK-9 in these cells. Transcriptional elongation in the C. elegans germline thus appears to be uniquely regulated, which may be a novel facet of germline identity. PMID:23903194

  2. Prevalence of germline TP53 mutations in HER2+ breast cancer patients.

    PubMed

    Rath, Michelle G; Masciari, Serena; Gelman, Rebecca; Miron, Alexander; Miron, Penelope; Foley, Kathleen; Richardson, Andrea L; Krop, Ian E; Verselis, Sigitas J; Dillon, Deborah A; Garber, Judy E

    2013-05-01

    Breast cancer is the most frequent tumor in Li-Fraumeni syndrome (LFS), a rare inherited cancer syndrome associated with germline mutations in the TP53 gene. Recent data show that breast cancer in germline TP53 mutation carriers is commonly HER2+ (63-83 %). We assessed the prevalence of germline TP53 mutations in a cohort of women with HER2+ breast cancer diagnosed age ≤50 years. We identified blood specimens from 213 women with primary invasive HER2+ breast cancer age ≤50 years from a single center. Exon grouping analysis sequencing and multiplex ligation-dependent probe amplification techniques were used to screen for germline TP53 mutations. Among 213 women with HER2+ breast cancer age ≤50 years, 3 (ages at diagnosis 23, 32, 44 years) were found to carry a TP53 mutation (1.4 %, 95 % CI 0.3-4.1 %). ER/PR status was not uniform. Two TP53 carriers met Chompret criteria for LFS; none met classic LFS criteria. Although two-thirds of breast cancers in women with TP53 mutations are HER2+, we observed a low prevalence of germline TP53 mutations among unselected young women with HER2+ breast cancer. Given the potential clinical impact, consideration of germline TP53 testing should be given to young women with HER2+ breast cancer, especially if family cancer history is notable.

  3. Dietary folate and APC mutations in sporadic colorectal cancer.

    PubMed

    de Vogel, Stefan; van Engeland, Manon; Lüchtenborg, Margreet; de Bruïne, Adriaan P; Roemen, Guido M J M; Lentjes, Marjolein H F M; Goldbohm, R Alexandra; van den Brandt, Piet A; de Goeij, Anton F P M; Weijenberg, Matty P

    2006-12-01

    Folate deficiency has been associated with colorectal cancer risk and may be involved in colorectal carcinogenesis through increased chromosome instability, gene mutations, and aberrant DNA methylation. Within the Netherlands Cohort Study on diet and cancer, we investigated the associations between dietary folate intake and colorectal cancer risk with (APC(+)) and without (APC(-)) truncating APC mutations, accounting for hMLH1 expression and K-ras mutations. In total, 528 cases and 4200 subcohort members were available for data analyses of the study cohort (n = 120,852) from a follow-up period between 2.3 and 7.3 y after baseline. Adjusted gender-specific incidence rate ratios (RR) over tertiles of folate intake were calculated in case-cohort analyses for colon and rectal cancer. Although relatively high folate intake was not associated with overall colorectal cancer risk, it reduced the risk of APC(-)colon tumors in men (RR 0.58, 95% CI 0.32-1.05, P(trend) = 0.06 for the highest vs. lowest tertile of folate intake). In contrast, it was positively associated with APC(+) colon tumors in men (highest vs. lowest tertile: RR 2.77, 95% CI 1.29-5.95, P(trend) = 0.008) and was even stronger when the lack of hMLH1 expression and K-ras mutations were excluded (RR 3.99, 95% CI 1.43-11.14, P(trend) = 0.007). Such positive associations were not observed among women; nor was folate intake associated with rectal cancer when APC mutation status was taken into account. Relatively high folate consumption reduced the risk of APC(-) colon tumors, but folate intake was positively associated with APC(+) colon tumors among men. These opposite results may indicate that folate enhances colorectal carcinogenesis through a distinct APC mutated pathway.

  4. Germline modification of domestic animals.

    PubMed

    Tang, L; González, R; Dobrinski, I

    2015-01-01

    Genetically-modified domestic animal models are of increasing significance in biomedical research and agriculture. As authentic ES cells derived from domestic animals are not yet available, the prevailing approaches for engineering genetic modifications in those animals are pronuclear microinjection and somatic cell nuclear transfer (SCNT, also known as cloning). Both pronuclear microinjection and SCNT are inefficient, costly, and time-consuming. In animals produced by pronuclear microinjection, the exogenous transgene is usually inserted randomly into the genome, which results in highly variable expression patterns and levels in different founders. Therefore, significant efforts are required to generate and screen multiple founders to obtain animals with optimal transgene expression. For SCNT, specific genetic modifications (both gain-of-function and loss-of-function) can be engineered and carefully selected in the somatic cell nucleus before nuclear transfer. SCNT has been used to generate a variety of genetically modified animals such as goats, pigs, sheep and cattle; however, animals resulting from SCNT frequently suffer from developmental abnormalities associated with incomplete nuclear reprogramming. Other strategies to generate genetically-modified animals rely on the use of the spermatozoon as a natural vector to introduce genetic material into the female gamete. This sperm mediated DNA transfer (SMGT) combined with intracytoplasmatic sperm injection (ICSI) has relatively high efficiency and allows the insertion of large DNA fragments, which, in turn, enhance proper gene expression. An approach currently being developed to complement SCNT for producing genetically modified animals is germ cell transplantation using genetically modified male germline stem cells (GSCs). This approach relies on the ability of GSCs that are genetically modified in vitro to colonize the recipient testis and produce donor derived sperm upon transplantation. As the genetic change

  5. Germline modification of domestic animals

    PubMed Central

    Tang, L.; González, R.; Dobrinski, I.

    2016-01-01

    Genetically-modified domestic animal models are of increasing significance in biomedical research and agriculture. As authentic ES cells derived from domestic animals are not yet available, the prevailing approaches for engineering genetic modifications in those animals are pronuclear microinjection and somatic cell nuclear transfer (SCNT, also known as cloning). Both pronuclear microinjection and SCNT are inefficient, costly, and time-consuming. In animals produced by pronuclear microinjection, the exogenous transgene is usually inserted randomly into the genome, which results in highly variable expression patterns and levels in different founders. Therefore, significant efforts are required to generate and screen multiple founders to obtain animals with optimal transgene expression. For SCNT, specific genetic modifications (both gain-of-function and loss-of-function) can be engineered and carefully selected in the somatic cell nucleus before nuclear transfer. SCNT has been used to generate a variety of genetically modified animals such as goats, pigs, sheep and cattle; however, animals resulting from SCNT frequently suffer from developmental abnormalities associated with incomplete nuclear reprogramming. Other strategies to generate genetically-modified animals rely on the use of the spermatozoon as a natural vector to introduce genetic material into the female gamete. This sperm mediated DNA transfer (SMGT) combined with intracytoplasmatic sperm injection (ICSI) has relatively high efficiency and allows the insertion of large DNA fragments, which, in turn, enhance proper gene expression. An approach currently being developed to complement SCNT for producing genetically modified animals is germ cell transplantation using genetically modified male germline stem cells (GSCs). This approach relies on the ability of GSCs that are genetically modified in vitro to colonize the recipient testis and produce donor derived sperm upon transplantation. As the genetic change

  6. Rarity of CDK4 germline mutations in familial melanoma.

    PubMed

    Goldstein, A M; Chidambaram, A; Halpern, A; Holly, E A; Guerry IV, D; Sagebiel, R; Elder, D E; Tucker, M A

    2002-02-01

    To date, two genes have been implicated in melanoma pathogenesis. The first, CDKN2A, is a tumour suppressor gene with germline mutations detected in 20% of melanoma-prone families. The second, CDK4, is an oncogene with co-segregating germline mutations detected in only three kindreds worldwide. We examined 16 American melanoma-prone families for mutations in all coding exons of CDK4 and screened additional members of two previously reported families with the Arg24Cys germline CDK4 mutation to evaluate the penetrance of the mutation. No new CDK4 mutations were identified. In the two Arg24Cys families, the penetrance was estimated to be 63%. Overall, 12 out of 12 invasive melanoma patients, none out of one in situ melanoma patient, five out of 13 dysplastic naevi patients, two out of 15 unaffected family members, and none out of 10 spouses carried the Arg24Cys mutation. Dysplastic naevi did not strongly co-segregate with the Arg24Cys mutation. Thus the phenotype observed in melanoma-prone CDK4 families appears to be more complex than just the CDK4 mutation. Both genetic and environmental factors are likely to contribute to the occurrence of melanoma and dysplastic naevi in these families. In summary, although CDK4 is a melanoma susceptibility gene, it plays a minor role in hereditary melanoma.

  7. Germline TERT promoter mutations are rare in familial melanoma.

    PubMed

    Harland, Mark; Petljak, Mia; Robles-Espinoza, Carla Daniela; Ding, Zhihao; Gruis, Nelleke A; van Doorn, Remco; Pooley, Karen A; Dunning, Alison M; Aoude, Lauren G; Wadt, Karin A W; Gerdes, Anne-Marie; Brown, Kevin M; Hayward, Nicholas K; Newton-Bishop, Julia A; Adams, David J; Bishop, D Timothy

    2016-01-01

    Germline CDKN2A mutations occur in 40 % of 3-or-more case melanoma families while mutations of CDK4, BAP1, and genes involved in telomere function (ACD, TERF2IP, POT1), have also been implicated in melanomagenesis. Mutation of the promoter of the telomerase reverse transcriptase (TERT) gene (c.-57 T>G variant) has been reported in one family. We tested for the TERT promoter variant in 675 multicase families wild-type for the known high penetrance familial melanoma genes, 1863 UK population-based melanoma cases and 529 controls. Germline lymphocyte telomere length was estimated in carriers. The c.-57 T>G TERT promoter variant was identified in one 7-case family with multiple primaries and early age of onset (earliest, 15 years) but not among population cases or controls. One family member had multiple primary melanomas, basal cell carcinomas and a bladder tumour. The blood leukocyte telomere length of a carrier was similar to wild-type cases. We provide evidence confirming that a rare promoter variant of TERT (c.-57 T>G) is associated with high penetrance, early onset melanoma and potentially other cancers, and explains <1 % of UK melanoma multicase families. The identification of POT1 and TERT germline mutations highlights the importance of telomere integrity in melanoma biology.

  8. Human germline antibody gene segments encode polyspecific antibodies.

    PubMed

    Willis, Jordan R; Briney, Bryan S; DeLuca, Samuel L; Crowe, James E; Meiler, Jens

    2013-04-01

    Structural flexibility in germline gene-encoded antibodies allows promiscuous binding to diverse antigens. The binding affinity and specificity for a particular epitope typically increase as antibody genes acquire somatic mutations in antigen-stimulated B cells. In this work, we investigated whether germline gene-encoded antibodies are optimal for polyspecificity by determining the basis for recognition of diverse antigens by antibodies encoded by three VH gene segments. Panels of somatically mutated antibodies encoded by a common VH gene, but each binding to a different antigen, were computationally redesigned to predict antibodies that could engage multiple antigens at once. The Rosetta multi-state design process predicted antibody sequences for the entire heavy chain variable region, including framework, CDR1, and CDR2 mutations. The predicted sequences matched the germline gene sequences to a remarkable degree, revealing by computational design the residues that are predicted to enable polyspecificity, i.e., binding of many unrelated antigens with a common sequence. The process thereby reverses antibody maturation in silico. In contrast, when designing antibodies to bind a single antigen, a sequence similar to that of the mature antibody sequence was returned, mimicking natural antibody maturation in silico. We demonstrated that the Rosetta computational design algorithm captures important aspects of antibody/antigen recognition. While the hypervariable region CDR3 often mediates much of the specificity of mature antibodies, we identified key positions in the VH gene encoding CDR1, CDR2, and the immunoglobulin framework that are critical contributors for polyspecificity in germline antibodies. Computational design of antibodies capable of binding multiple antigens may allow the rational design of antibodies that retain polyspecificity for diverse epitope binding.

  9. Human Germline Antibody Gene Segments Encode Polyspecific Antibodies

    PubMed Central

    Willis, Jordan R.; Briney, Bryan S.; DeLuca, Samuel L.; Crowe, James E.; Meiler, Jens

    2013-01-01

    Structural flexibility in germline gene-encoded antibodies allows promiscuous binding to diverse antigens. The binding affinity and specificity for a particular epitope typically increase as antibody genes acquire somatic mutations in antigen-stimulated B cells. In this work, we investigated whether germline gene-encoded antibodies are optimal for polyspecificity by determining the basis for recognition of diverse antigens by antibodies encoded by three VH gene segments. Panels of somatically mutated antibodies encoded by a common VH gene, but each binding to a different antigen, were computationally redesigned to predict antibodies that could engage multiple antigens at once. The Rosetta multi-state design process predicted antibody sequences for the entire heavy chain variable region, including framework, CDR1, and CDR2 mutations. The predicted sequences matched the germline gene sequences to a remarkable degree, revealing by computational design the residues that are predicted to enable polyspecificity, i.e., binding of many unrelated antigens with a common sequence. The process thereby reverses antibody maturation in silico. In contrast, when designing antibodies to bind a single antigen, a sequence similar to that of the mature antibody sequence was returned, mimicking natural antibody maturation in silico. We demonstrated that the Rosetta computational design algorithm captures important aspects of antibody/antigen recognition. While the hypervariable region CDR3 often mediates much of the specificity of mature antibodies, we identified key positions in the VH gene encoding CDR1, CDR2, and the immunoglobulin framework that are critical contributors for polyspecificity in germline antibodies. Computational design of antibodies capable of binding multiple antigens may allow the rational design of antibodies that retain polyspecificity for diverse epitope binding. PMID:23637590

  10. Insights into Degron Recognition by APC/C Coactivators from the Structure of an Acm1-Cdh1 Complex

    PubMed Central

    He, Jun; Chao, William C.H.; Zhang, Ziguo; Yang, Jing; Cronin, Nora; Barford, David

    2013-01-01

    Summary The anaphase-promoting complex/cyclosome (APC/C) regulates sister chromatid segregation and the exit from mitosis. Selection of most APC/C substrates is controlled by coactivator subunits (either Cdc20 or Cdh1) that interact with substrate destruction motifs—predominantly the destruction (D) box and KEN box degrons. How coactivators recognize D box degrons and how this is inhibited by APC/C regulatory proteins is not defined at the atomic level. Here, from the crystal structure of S. cerevisiae Cdh1 in complex with its specific inhibitor Acm1, which incorporates D and KEN box pseudosubstrate motifs, we describe the molecular basis for D box recognition. Additional interactions between Acm1 and Cdh1 identify a third protein-binding site on Cdh1 that is likely to confer coactivator-specific protein functions including substrate association. We provide a structural rationalization for D box and KEN box recognition by coactivators and demonstrate that many noncanonical APC/C degrons bind APC/C coactivators at the D box coreceptor. PMID:23707760

  11. Molecular analysis of mutations for the adenomatous polyposis coli (APC) gene in Romanian patients with colorectal cancer.

    PubMed

    Toma, M; Cimponeriu, D; Pompilia, A; Stavarachi, M; Beluşică, L; Radu, I; Gavrilă, L

    2008-01-01

    Mutations in adenomatous polyposis coli (APC) gene have not been previously characterized among Romanian patients with colorectal cancer (CRC). We initiate this study to detect the mutations in APC gene in blood and tumor samples collected from 16 patients (10 men and 6 women) and blood samples from 21 first and second degree relatives of the patients. For this the presence of mutations in exons 6, 7, 12, 13, 14 as well as in regions B, L and W of exon 15 was investigated using PCR multiplex. In the same time, we have searched for 5 bp deletions at codon 1061 of APC gene by PAGE and SSCP methods. These methods allowed us to evidence identification of the presence of mutations in samples from 7 individuals. In one patient, was detected a deletion of exon 13th of APC gene both in DNA extracted from blood and tumor samples. Multiple deletions (e.g. in exon 6, 12, and in 15L and 15W regions) in DNA extracted from the tumor sample were detected, but not in DNA probe obtained from blood cells. We can speculate that these mutations are an example of genomic instability accompanying the malignancy. Till now, no mutation affecting 1061 codon of APC gene was identified in the patients investigated in our study.

  12. The Mitotic Checkpoint Complex Requires an Evolutionary Conserved Cassette to Bind and Inhibit Active APC/C.

    PubMed

    Di Fiore, Barbara; Wurzenberger, Claudia; Davey, Norman E; Pines, Jonathon

    2016-12-15

    The Spindle Assembly Checkpoint (SAC) ensures genomic stability by preventing sister chromatid separation until all chromosomes are attached to the spindle. It catalyzes the production of the Mitotic Checkpoint Complex (MCC), which inhibits Cdc20 to inactivate the Anaphase Promoting Complex/Cyclosome (APC/C). Here we show that two Cdc20-binding motifs in BubR1 of the recently identified ABBA motif class are crucial for the MCC to recognize active APC/C-Cdc20. Mutating these motifs eliminates MCC binding to the APC/C, thereby abolishing the SAC and preventing cells from arresting in response to microtubule poisons. These ABBA motifs flank a KEN box to form a cassette that is highly conserved through evolution, both in the arrangement and spacing of the ABBA-KEN-ABBA motifs, and association with the amino-terminal KEN box required to form the MCC. We propose that the ABBA-KEN-ABBA cassette holds the MCC onto the APC/C by binding the two Cdc20 molecules in the MCC-APC/C complex. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Substrate Recognition by the Cdh1 Destruction Box Receptor Is a General Requirement for APC/CCdh1-mediated Proteolysis.

    PubMed

    Qin, Liang; Guimarães, Dimitrius Santiago P S F; Melesse, Michael; Hall, Mark C

    2016-07-22

    The anaphase-promoting complex, or cyclosome (APC/C), is a ubiquitin ligase that selectively targets proteins for degradation in mitosis and the G1 phase and is an important component of the eukaryotic cell cycle control system. How the APC/C specifically recognizes its substrates is not fully understood. Although well characterized degron motifs such as the destruction box (D-box) and KEN-box are commonly found in APC/C substrates, many substrates apparently lack these motifs. A variety of alternative APC/C degrons have been reported, suggesting either that multiple modes of substrate recognition are possible or that our definitions of degron structure are incomplete. We used an in vivo yeast assay to compare the G1 degradation rate of 15 known substrates of the APC/C co-activator Cdh1 under normal conditions and conditions that impair binding of D-box, KEN-box, and the recently identified ABBA motif degrons to Cdh1. The D-box receptor was required for efficient proteolysis of all Cdh1 substrates, despite the absence of canonical D-boxes in many. In contrast, the KEN-box receptor was only required for normal proteolysis of a subset of substrates and the ABBA motif receptor for a single substrate in our system. Our results suggest that binding to the D-box receptor may be a shared requirement for recognition and processing of all Cdh1 substrates.

  14. Colon cancer prevention by detection of APC gene mutation in a family with attenuated familial adenomatous polyposis.

    PubMed

    Poovorawan, Kittiyod; Suksawatamnuay, Sirinporn; Sahakitrungruang, Chucheep; Treeprasertsuk, Sombat; Wisedopas, Naruemon; Komolmit, Piyawat; Poovorawan, Yong

    2012-01-01

    Genetic mutation is a significant factor in colon CA pathogenesis. Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary disease characterized by multiple colorectal adenomatous polyps affecting a number of cases in the family. This report focuses on a family with attenuated familial adenomatous polyposis (AFAP) with exon 4 mutation, c.481C>T p.Q161X of the APC gene. We analyzed 20 members of a family with AFAP. Clinical and endoscopic data were collected for phenotype determination. Genetic analysis was also performed by direct sequencing of the APC gene. Five patients with a phenotype of AFAP were found. Endoscopic polyposis was demonstrated among the second generation with genotype mutation of the disease (age > 50 years) consistent with delayed phenotypic adenomatous polyposis in AFAP. APC gene mutation was identified in exon 4 of the APC gene, with mutation points of c.481C>T p.Q161X. Laparoscopic subtotal colectomy was performed to prevent carcinogenesis. A family with attenuated familial adenomatous polyposis of APC related to exon 4 mutation, c.481C>T p.Q161X, was reported and the phenotypic finding was confirmed by endoscopic examination. Genetic mutation analysis might be advantageous in AFAP for long term colon cancer prevention and management due to subtle or asymptomatic phenotype presentation in early adulthood.

  15. Germline and somatic KLLN alterations in breast cancer dysregulate G2 arrest

    PubMed Central

    Nizialek, Emily A.; Peterson, Charissa; Mester, Jessica L.; Downes-Kelly, Erinn; Eng, Charis

    2013-01-01

    PTEN is a well-described predisposition gene for Cowden syndrome (CS), a familial cancer syndrome characterized by a high risk of breast and other cancers. KLLN, which shares a bidirectional promoter with PTEN, causes cell cycle arrest and apoptosis. We previously identified germline hypermethylation of the KLLN promoter in 37% of PTEN mutation-negative CS/CS-like (CSL) patients. Patients with germline KLLN hypermethylation have an increased prevalence of breast and renal cancers when compared with PTEN mutation carriers. We have consequently sought to identify and characterize germline KLLN variants/mutations in CS/CSL and in apparently sporadic breast cancer patients. KLLN variants in CS/CSL patients are rare (1 of 136, 0.007%). Interestingly, among 438 breast cancer patients, 13 (3%) have germline KLLN variants when compared with none in 128 controls (P = 0.049). Patients with KLLN variants have a family history of breast cancer when compared with those without (P = 0.02). We demonstrate that germline KLLN variants dysregulate the cell cycle at G2. Of 24 breast carcinomas analyzed, 3 (13%) have somatic KLLN hemizygous deletions, with somatic loss of the wild-type allele in a patient with germline KLLN p.Leu119Leu. Of 452 breast carcinomas in The Cancer Genome Atlas project, 93 (21%) have KLLN hemizygous or homozygous deletions. This is the first study to associate germline KLLN variants with sporadic breast cancer and to recognize somatic KLLN deletions in breast carcinomas. Our observations suggest that KLLN may be a low penetrance susceptibility factor for apparently sporadic breast cancer. PMID:23446638

  16. Proteomic profiling of a mouse model of acute intestinal Apc deletion leads to identification of potential novel biomarkers of human colorectal cancer (CRC).

    PubMed

    Hammoudi, Abeer; Song, Fei; Reed, Karen R; Jenkins, Rosalind E; Meniel, Valerie S; Watson, Alastair J M; Pritchard, D Mark; Clarke, Alan R; Jenkins, John R

    2013-10-25

    Colorectal cancer (CRC) is the fourth most common cause of cancer-related death worldwide. Accurate non-invasive screening for CRC would greatly enhance a population's health. Adenomatous polyposis coli (Apc) gene mutations commonly occur in human colorectal adenomas and carcinomas, leading to Wnt signalling pathway activation. Acute conditional transgenic deletion of Apc in murine intestinal epithelium (AhCre(+)Apc(fl)(/)(fl)) causes phenotypic changes similar to those found during colorectal tumourigenesis. This study comprised a proteomic analysis of murine small intestinal epithelial cells following acute Apc deletion to identify proteins that show altered expression during human colorectal carcinogenesis, thus identifying proteins that may prove clinically useful as blood/serum biomarkers of colorectal neoplasia. Eighty-one proteins showed significantly increased expression following iTRAQ analysis, and validation of nine of these by Ingenuity Pathaway Analysis showed they could be detected in blood or serum. Expression was assessed in AhCre(+)Apc(fl)(/)(fl) small intestinal epithelium by immunohistochemistry, western blot and quantitative real-time PCR; increased nucelolin concentrations were also detected in the serum of AhCre(+)Apc(fl)(/)(fl) and Apc(Min)(/)(+) mice by ELISA. Six proteins; heat shock 60kDa protein 1, Nucleolin, Prohibitin, Cytokeratin 18, Ribosomal protein L6 and DEAD (Asp-Glu-Ala-Asp) box polypeptide 5,were selected for further investigation. Increased expression of 4 of these was confirmed in human CRC by qPCR. In conclusion, several novel candidate biomarkers have been identified from analysis of transgenic mice in which the Apc gene was deleted in the intestinal epithelium that also showed increased expression in human CRC. Some of these warrant further investigation as potential serum-based biomarkers of human CRC.

  17. Tumour Suppressor Adenomatous Polyposis Coli (APC) localisation is regulated by both Kinesin-1 and Kinesin-2

    PubMed Central

    Ruane, Peter T.; Gumy, Laura F.; Bola, Becky; Anderson, Beverley; Wozniak, Marcin J.; Hoogenraad, Casper C.; Allan, Victoria J.

    2016-01-01

    Microtubules and their associated proteins (MAPs) underpin the polarity of specialised cells. Adenomatous polyposis coli (APC) is one such MAP with a multifunctional agenda that requires precise intracellular localisations. Although APC has been found to associate with kinesin-2 subfamily members, the exact mechanism for the peripheral localization of APC remains unclear. Here we show that the heavy chain of kinesin-1 directly interacts with the APC C-terminus, contributing to the peripheral localisation of APC in fibroblasts. In rat hippocampal neurons the kinesin-1 binding domain of APC is required for its axon tip enrichment. Moreover, we demonstrate that APC requires interactions with both kinesin-2 and kinesin-1 for this localisation. Underlining the importance of the kinesin-1 association, neurons expressing APC lacking kinesin-1-binding domain have shorter axons. The identification of this novel kinesin-1-APC interaction highlights the complexity and significance of APC localisation in neurons. PMID:27272132

  18. OGA heterozygosity suppresses intestinal tumorigenesis in Apc(min/+) mice.

    PubMed

    Yang, Y R; Jang, H-J; Yoon, S; Lee, Y H; Nam, D; Kim, I S; Lee, H; Kim, H; Choi, J H; Kang, B H; Ryu, S H; Suh, P-G

    2014-07-07

    Emerging evidence suggests that aberrant O-GlcNAcylation is associated with tumorigenesis. Many oncogenic factors are O-GlcNAcylated, which modulates their functions. However, it remains unclear how O-GlcNAcylation and O-GlcNAc cycling enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), affect the development of cancer in animal models. In this study, we show that reduced level of OGA attenuates colorectal tumorigenesis induced by Adenomatous polyposis coli (Apc) mutation. The levels of O-GlcNAcylation and O-GlcNAc cycling enzymes were simultaneously upregulated in intestinal adenomas from mice, and in human patients. In two independent microarray data sets, the expression of OGA and OGT was significantly associated with poor cancer-specific survival of colorectal cancer (CRC) patients. In addition, OGA heterozygosity, which results in increased levels of O-GlcNAcylation, attenuated intestinal tumor formation in the Apc(min/+) background. Apc(min/+) OGA(+/-) mice exhibited a significantly increased survival rate compared with Apc(min/+) mice. Consistent with this, Apc(min/+) OGA(+/-) mice expressed lower levels of Wnt target genes than Apc(min/+). However, the knockout of OGA did not affect Wnt/β-catenin signaling. Overall, these findings suggest that OGA is crucial for tumor growth in CRC independently of Wnt/β-catenin signaling.

  19. The APC/C in female mammalian meiosis I.

    PubMed

    Homer, Hayden

    2013-08-01

    The anaphase-promoting complex or cyclosome (APC/C) orchestrates a meticulously controlled sequence of proteolytic events critical for proper cell cycle progression, the details of which have been most extensively elucidated during mitosis. It has become apparent, however, that the APC/C, particularly when acting in concert with its Cdh1 co-activator (APC/C(Cdh1)), executes a staggeringly diverse repertoire of functions that extend its remit well outside the bounds of mitosis. Findings over the past decade have not only earmarked mammalian oocyte maturation as one such case in point but have also begun to reveal a complex pattern of APC/C regulation that underpins many of the oocyte's unique developmental attributes. This review will encompass the latest findings pertinent to the APC/C, especially APC/C(Cdh1), in mammalian oocytes and how its activity and substrates shape the stop-start tempo of female mammalian first meiotic division and the challenging requirement for assembling spindles in the absence of centrosomes.

  20. Insights into anaphase promoting complex TPR subdomain assembly from a CDC26-APC6 structure

    SciTech Connect

    Wang, Jing; Dye, Billy T; Rajashankar, Kanagalaghatta R; Kurinov, Igor; Schulman, Brenda A

    2009-12-01

    The multisubunit anaphase promoting complex (APC) is an essential cell-cycle regulator. Although CDC26 is known to have a role in APC assembly, its molecular function has remained unclear. Biophysical, structural and genetic studies presented here reveal that CDC26 stabilizes the structure of APC6, a core TPR protein required for APC integrity. Notably, CDC26-APC6 association involves an intermolecular TPR mimic composed of one helix from each protein.

  1. Genomic signatures of germline gene expression.

    PubMed

    McVicker, Graham; Green, Phil

    2010-11-01

    Transcribed regions in the human genome differ from adjacent intergenic regions in transposable element density, crossover rates, and asymmetric substitution and sequence composition patterns. We tested whether these differences reflect selection or are instead a byproduct of germline transcription, using publicly available gene expression data from a variety of germline and somatic tissues. Crossover rate shows a strong negative correlation with gene expression in meiotic tissues, suggesting that crossover is inhibited by transcription. Strand-biased composition (G+T content) and A → G versus T → C substitution asymmetry are both positively correlated with germline gene expression. We find no evidence for a strand bias in allele frequency data, implying that the substitution asymmetry reflects a mutation rather than a fixation bias. The density of transposable elements is positively correlated with germline expression, suggesting that such elements preferentially insert into regions that are actively transcribed. For each of the features examined, our analyses favor a nonselective explanation for the observed trends and point to the role of germline gene expression in shaping the mammalian genome.

  2. Achieving immortality in the C. elegans germline.

    PubMed

    Smelick, Chris; Ahmed, Shawn

    2005-01-01

    Germline immortality is a topic that has intrigued theoretical biologists interested in aging for over a century. The germ cell lineage can be passed from one generation to the next, indefinitely. In contrast, somatic cells are typically only needed for a single generation and are then discarded. Germ cells may, therefore, harbor rejuvenation mechanisms that enable them to proliferate for eons. Such processes are thought to be either absent from or down-regulated in somatic cells, although cell non-autonomous forms of rejuvenation are formally possible. A thorough description of mechanisms that foster eternal youth in germ cells is lacking. The mysteries of germline immortality are being addressed in the nematode Caenorhabditis elegans by studying mutants that reproduce normally for several generations but eventually become sterile. The mortal germline mutants probably become sterile as a consequence of accumulating various forms of heritable cellular damage. Such mutants are abundant, indicating that several different biochemical pathways are required to rejuvenate the germline. Thus, forward genetics should help to define mechanisms that enable the germline to achieve immortality.

  3. Spontaneous generation of germline characteristics in mouse fibrosarcoma cells

    NASA Astrophysics Data System (ADS)

    Ma, Zhan; Hu, Yao; Jiang, Guoying; Hou, Jun; Liu, Ruilai; Lu, Yuan; Liu, Chunfang

    2012-10-01

    Germline/embryonic-specific genes have been found to be activated in somatic tumors. In this study, we further showed that cells functioning as germline could be present in mouse fibrosarcoma cells (L929 cell line). Early germline-like cells spontaneously appeared in L929 cells and further differentiated into oocyte-like cells. These germline-like cells can, in turn, develop into blastocyst-like structures in vitro and cause teratocarcinomas in vivo, which is consistent with natural germ cells in function. Generation of germline-like cells from somatic tumors might provide a novel way to understand why somatic cancer cells have strong features of embryonic/germline development. It is thought that the germline traits of tumors are associated with the central characteristics of malignancy, such as immortalization, invasion, migration and immune evasion. Therefore, germline-like cells in tumors might provide potential targets to tumor biology, diagnosis and therapy.

  4. Spontaneous generation of germline characteristics in mouse fibrosarcoma cells.

    PubMed

    Ma, Zhan; Hu, Yao; Jiang, Guoying; Hou, Jun; Liu, Ruilai; Lu, Yuan; Liu, Chunfang

    2012-01-01

    Germline/embryonic-specific genes have been found to be activated in somatic tumors. In this study, we further showed that cells functioning as germline could be present in mouse fibrosarcoma cells (L929 cell line). Early germline-like cells spontaneously appeared in L929 cells and further differentiated into oocyte-like cells. These germline-like cells can, in turn, develop into blastocyst-like structures in vitro and cause teratocarcinomas in vivo, which is consistent with natural germ cells in function. Generation of germline-like cells from somatic tumors might provide a novel way to understand why somatic cancer cells have strong features of embryonic/germline development. It is thought that the germline traits of tumors are associated with the central characteristics of malignancy, such as immortalization, invasion, migration and immune evasion. Therefore, germline-like cells in tumors might provide potential targets to tumor biology, diagnosis and therapy.

  5. Germline CDH1 deletions in hereditary diffuse gastric cancer families

    PubMed Central

    Oliveira, Carla; Senz, Janine; Kaurah, Pardeep; Pinheiro, Hugo; Sanges, Remo; Haegert, Anne; Corso, Giovanni; Schouten, Jan; Fitzgerald, Rebecca; Vogelsang, Holger; Keller, Gisela; Dwerryhouse, Sarah; Grimmer, Donna; Chin, Suet-Feung; Yang, Han-Kwang; Jackson, Charles E.; Seruca, Raquel; Roviello, Franco; Stupka, Elia; Caldas, Carlos; Huntsman, David

    2009-01-01

    Germline CDH1 point or small frameshift mutations can be identified in 30–50% of hereditary diffuse gastric cancer (HDGC) families. We hypothesized that CDH1 genomic rearrangements would be found in HDGC and identified 160 families with either two gastric cancers in first-degree relatives and with at least one diffuse gastric cancer (DGC) diagnosed before age 50, or three or more DGC in close relatives diagnosed at any age. Sixty-seven carried germline CDH1 point or small frameshift mutations. We screened germline DNA from the 93 mutation negative probands for large genomic rearrangements by Multiplex Ligation-Dependent Probe Amplification. Potential deletions were validated by RT–PCR and breakpoints cloned using a combination of oligo-CGH-arrays and long-range-PCR. In-silico analysis of the CDH1 locus was used to determine a potential mechanism for these rearrangements. Six of 93 (6.5%) previously described mutation negative HDGC probands, from low GC incidence populations (UK and North America), carried genomic deletions (UK and North America). Two families carried an identical deletion spanning 193 593 bp, encompassing the full CDH3 sequence and CDH1 exons 1 and 2. Other deletions affecting exons 1, 2, 15 and/or 16 were identified. The statistically significant over-representation of Alus around breakpoints indicates it as a likely mechanism for these deletions. When all mutations and deletions are considered, the overall frequency of CDH1 alterations in HDGC is ∼46% (73/160). CDH1 large deletions occur in 4% of HDGC families by mechanisms involving mainly non-allelic homologous recombination in Alu repeat sequences. As the finding of pathogenic CDH1 mutations is useful for management of HDGC families, screening for deletions should be offered to at-risk families. PMID:19168852

  6. A proven de novo germline mutation in HNPCC.

    PubMed

    Kraus, C; Kastl, S; Günther, K; Klessinger, S; Hohenberger, W; Ballhausen, W G

    1999-12-01

    Hereditary non-polyposis colon cancer (HNPCC) is a heterogeneous group of tumour predisposition syndromes caused by germline mutations in at least four different mismatch repair genes. HNPCC patients are prone to the development of carcinomas of the intestinal tract and other specific sites. Identification of presumptive HNPCC patients is primarily based on a positive family history of colorectal cancer in at least two generations. In the course of mutation screening of the MLH1 and MSH2 genes in patients manifesting a carcinoma of the HNPCC tumour spectrum before the age of 45 years, we identified a germline MSH2 344delA frameshift mutation in a male proband. This index patient, at the age of 25 years, initially developed a large rectal adenoma that was removed by polypectomy. Ten years later he was operated on for an invasive right sided colon carcinoma in the caecum (International Union Against Cancer (UICC) stage III). The mother and father, aged 61 and 66 years, respectively, were healthy and had no family history of colorectal cancer. Subsequent molecular analyses excluded the germinal MSH2 344delA alteration identified in their son and at the same time paternity was confirmed with a set of informative polymorphic markers. Thus, the genetic alteration identified in our patient definitely represented a de novo germline mutation in one of the major HNPCC genes. This case report of a patient with colorectal cancer at a relatively young age with no family history is intended to encourage mutation screening of the MSH2 and MLH1 genes in similar cases to find out whether this group of patients contains an increased proportion of de novo mutations in mismatch repair genes.

  7. Germline Modification and Engineering in Avian Species.

    PubMed

    Lee, Hong Jo; Lee, Hyung Chul; Han, Jae Yong

    2015-09-01

    Production of genome-edited animals using germline-competent cells and genetic modification tools has provided opportunities for investigation of biological mechanisms in various organisms. The recently reported programmed genome editing technology that can induce gene modification at a target locus in an efficient and precise manner facilitates establishment of animal models. In this regard, the demand for genome-edited avian species, which are some of the most suitable model animals due to their unique embryonic development, has also increased. Furthermore, germline chimera production through long-term culture of chicken primordial germ cells (PGCs) has facilitated research on production of genome-edited chickens. Thus, use of avian germline modification is promising for development of novel avian models for research of disease control and various biological mechanisms. Here, we discuss recent progress in genome modification technology in avian species and its applications and future strategies.

  8. The evolution of insect germline specification strategies

    PubMed Central

    Quan, Honghu; Lynch, Jeremy A.

    2016-01-01

    The establishment of the germline is essential for sexually reproducing organisms. In animals, there are two major strategies to specify the germline: maternal provision and zygotic induction. The molecular basis of the maternal provision mode has been well characterized in several model organisms (fly, frog, fish, and nematode), while that of the zygotic induction mode has mainly been studied in mammalian models such as the mouse. Shifts in germline determination modes occur unexpectedly frequently and many such shifts have occurred several times among insects. Given their general tractability and rapidly increasing genomic and genetic tools applicable to many species, the insects present a uniquely powerful model system for understanding major transitions in reproductive strategies, and developmental processes in general. PMID:27088076

  9. Analysis of adenomatous polyposis coli gene expression, APC locus-microsatellite instability and APC promoter methylation in the progression of melanocytic tumours.

    PubMed

    Korabiowska, Monika; Schlott, Thilo; Siems, Nils; Müller, Anegret; Cordon-Cardo, Carlos; Fischer, Gösta; Brinck, Ulrich

    2004-12-01

    Adenomatous polyposis coli gene (APC) defects have been demonstrated for the first time in familial adenomatous polyposis. Recent reports indicate that the APC gene is an intermediary between cell adhesion molecules and the cytoskeleton and that it may function as a gatekeeper of colonic epithelial proliferation. The objective of this study was to analyse APC's presence in lentigos, primary melanomas and melanoma metastases. By immunohistochemistry, APC was demonstrated in all lentigos, in 75 out of 88 primary melanomas and in 16 out of 28 melanoma lymphatic metastases. The percentage of immunolabelled tumour cells (APC index) in lentigos ranged between 5 and 69%, in primary melanomas between 0 and 98% and in melanoma metastases between 0 and 52%. Statistically significant differences between lentigos and primary melanomas and between lentigos and metastases in APC expression were found. In a multivariate analysis, APC showed an independent prognostic impact. Analysis of microsatellite instability in the APC locus was performed on 29 melanomas. Microsatellite instability was found in 5/29 melanomas and loss of heterozygosity in 1/29 melanomas. Promoter methylation of APC was found in 6/10 APC-negative primary melanomas and in 9/10 APC-negative melanoma lymphatic metastases investigated. We conclude about important role of APC alterations for melanoma progression.

  10. APC Yin-Yang haplotype associated with colorectal cancer risk.

    PubMed

    Garre, P; DE LA Hoya, M; Iniesta, P; Romera, A; Llovet, P; Gonzalez, S; Perez-Segura, P; Capella, G; Diaz-Rubio, E; Caldes, T

    2010-09-01

    The Yin-Yang haplotype is defined as two mismatched haplotypes (Yin and Yang) representing the majority of the existing haplotypes in a particular genomic region. The human adenomatous polyposis coli (APC) gene shows a Yin-Yang haplotype pattern accounting for 84% of all of the haplotypes existing in the Spanish population. Several association studies have been published regarding APC gene variants (SNPs and haplotypes) and colorectal cancer (CRC) risk. However, no studies concerning diplotype structure and CRC risk have been conducted. The aim of the present study was to investigate whether the APC Yin-Yang homozygote diplotype is over-represented in patients with sporadic CRC when compared to its distribution in controls, and its association with CRC risk. TaqMan(®) assays were used to genotype three tagSNPs selected across the APC Yin-Yang region. Frequencies of the APC Yin-Yang tagSNP alleles, haplotype and diplotype of 378 CRC cases and 642 controls were compared. Two Spanish CRC group samples were included [Hospital Clínico San Carlos in Madrid (HCSC) and Instituto Catalán de Oncología in Barcelona (ICO)]. Analysis of 157 consecutive CRC patients and 405 control subjects from HCSC showed a significative effect for the risk of CRC (OR=1.93; 95% CI 1.32-2.81; P=0.001). However, this effect was not confirmed in 221 CRC patients and 237 control subjects from ICO (OR=0.89; 95% CI 0.61-1.28; P=0.521). We found a significant association between the APC homozygote Yin-Yang diplotype and the risk of colorectal cancer in the HCSC samples. However, we did not observe this association in the ICO samples. These observations suggest that a study with a larger Spanish cohort is necessary to confirm the effects of the APC Yin-Yang diplotype on the risk of CRC.

  11. APC Yin-Yang haplotype associated with colorectal cancer risk

    PubMed Central

    GARRE, P.; DE LA HOYA, M.; INIESTA, P.; ROMERA, A.; LLOVET, P.; GONZALEZ, S.; PEREZ-SEGURA, P.; CAPELLA, G.; DIAZ-RUBIO, E.; CALDES, T.

    2010-01-01

    The Yin-Yang haplotype is defined as two mismatched haplotypes (Yin and Yang) representing the majority of the existing haplotypes in a particular genomic region. The human adenomatous polyposis coli (APC) gene shows a Yin-Yang haplotype pattern accounting for 84% of all of the haplotypes existing in the Spanish population. Several association studies have been published regarding APC gene variants (SNPs and haplotypes) and colorectal cancer (CRC) risk. However, no studies concerning diplotype structure and CRC risk have been conducted. The aim of the present study was to investigate whether the APC Yin-Yang homozygote diplotype is over-represented in patients with sporadic CRC when compared to its distribution in controls, and its association with CRC risk. TaqMan® assays were used to genotype three tagSNPs selected across the APC Yin-Yang region. Frequencies of the APC Yin-Yang tagSNP alleles, haplotype and diplotype of 378 CRC cases and 642 controls were compared. Two Spanish CRC group samples were included [Hospital Clínico San Carlos in Madrid (HCSC) and Instituto Catalán de Oncología in Barcelona (ICO)]. Analysis of 157 consecutive CRC patients and 405 control subjects from HCSC showed a significative effect for the risk of CRC (OR=1.93; 95% CI 1.32–2.81; P=0.001). However, this effect was not confirmed in 221 CRC patients and 237 control subjects from ICO (OR=0.89; 95% CI 0.61–1.28; P=0.521). We found a significant association between the APC homozygote Yin-Yang diplotype and the risk of colorectal cancer in the HCSC samples. However, we did not observe this association in the ICO samples. These observations suggest that a study with a larger Spanish cohort is necessary to confirm the effects of the APC Yin-Yang diplotype on the risk of CRC. PMID:22993613

  12. APC+/− alters colonic fibroblast proteome in FAP

    PubMed Central

    Dixon, Maketa P.; Blagoi, Elena L.; Nicolas, Emmanuelle; Seeholzer, Steven H.; Cheng, David; He, Yin A.; Coudry, Renata A.; Howard, Sharon D.; Riddle, Dawn M.; Cooper, Harry S.; Boman, Bruce M.; Conrad, Peggy; Crowell, James A.; Bellacosa, Alfonso; Knudson, Alfred; Yeung, Anthony T.; Kopelovich, Levy

    2011-01-01

    Here we compared the proteomes of primary fibroblast cultures derived from morphologically normal colonic mucosa of familial adenomatous polyposis (FAP) patients with those obtained from unaffected controls. The expression signature of about 19% of total fibroblast proteins separates FAP mutation carriers from unaffected controls (P < 0.01). More than 4,000 protein spots were quantified by 2D PAGE analysis, identifying 368 non-redundant proteins and 400 of their isoforms. Specifically, all three classes of cytoskeletal filaments and their regulatory proteins were altered as were oxidative stress response proteins. Given that FAP fibroblasts showed heightened sensitivity to transformation by KiMSV and SV40 including elevated levels of the p53 protein, events controlled in large measure by the Ras suppressor protein-1 (RSU-1) and oncogenic DJ-1, here we show decreased RSU1 and augmented DJ-1 expression in both fibroblasts and crypt-derived epithelial cells from morphologically normal colonic mucosa of FAP gene-carriers. The results indicate that heterozygosity for a mutant APC tumor suppressor gene alters the proteomes of both colon-derived normal fibroblasts in a gene-specific manner, consistent with a “one-hit” effect. PMID:21411865

  13. Severe Gardner Syndrome in Families with Mutations Restricted to a Specific Region of the APC Gene

    PubMed Central

    Davies, D. Rhodri; Armstrong, John G.; Thakker, Nalin; Horner, Keith; Guy, Simon P.; Clancy, Tara; Sloan, Phil; Blair, Val; Dodd, Chris; Warnes, Tom W.; Harris, Rodney; Evans, D. Gareth R.

    1995-01-01

    Familial adenomatous polyposis (FAP) is associated with a number of extraintestinal manifestations, which include osteomas, epidermoid cysts, and desmoid tumors, often referred to as “Gardner syndrome.” Recent studies have suggested that some of the phenotypic features of FAP are dependent on the position of the mutation within the APC gene. In particular, the correlation between congenital hypertrophy of the retinal pigment epithelium (CHRPE) and APC genotype indicates that affected families may be divided into distinct groups. We have investigated the association between the dento-osseous features of GS on dental panoramic radiographs (DPRs) and APC genotype in a regional cohort of FAP families. DPRs were performed on 84 affected individuals from 36 families, and the dento-osseous features of FAP were quantified by a weighted scoring system. Significant DPR abnormalities were present in 69% of affected individuals. The APC gene mutation was identified in 27 of these families, and for statistical analysis these were subdivided into three groups. Group 1 comprised 18 affected individuals from seven families with mutations 5' of exon 9; these families (except one) did not express CHRPE. Groups 2 comprised 38 individuals from 16 families with mutations between exon 9 and codon 1444, all of whom expressed CHRPE. Group 3 comprised 11 individuals from four families with mutations 3' of codon 1444, none of whom expressed CHRPE. Families with mutations 3' of codon 1444 had significantly more lesions on DPRs (P < .001) and appeared to have a higher incidence of desmoid tumors. These results suggest that the severity of some of the features of Gardner syndrome may correlate with genotype in FAP. ImagesFigure 2 PMID:7485167

  14. Germline transmission of a novel rat embryonic stem cell line derived from transgenic rats.

    PubMed

    Men, Hongsheng; Bauer, Beth A; Bryda, Elizabeth C

    2012-09-20

    Germline-competent rat embryonic stem (ES) cell lines are important resources for the creation of mutant rat models using ES-cell-based gene targeting technology. The ability to isolate germline-competent ES cell lines from any rat strain, including genetically modified strains, would allow for more sophisticated genetic manipulations without extensive breeding. Sprague Dawley (SD) males carrying an enhanced green fluorescent protein (EGFP) transgene were used as the founder animals for the derivation of ES cell lines. A number of ES cell lines were established and subjected to rigorous quality control testing that included assessment of pluripotency factor expression, karyotype analysis, and pathogen/sterility testing. Two male ES cell lines, SD-Tg.EC1/Rrrc and SD-Tg.EC8/Rrrc, were injected into blastocysts recovered from a cross of Dark Agouti (DA) males with SD females. Resulting chimeric animals were bred with wild-type SD mates to verify the germline transmissibility of the ES cell lines by identifying pups carrying the ES cell line-derived EGFP transgene. While both ES cell lines gave rise to chimeric animals, only SD-Tg.EC1 was germline competent. This confirms the feasibility of deriving germline-competent ES cell lines from transgenic rat strains and provides a novel ES cell line with a stable green fluorescent protein (GFP) reporter for future genetic manipulations to create new rat models.

  15. Germline and somatic mutations in the MTOR gene in focal cortical dysplasia and epilepsy

    PubMed Central

    Møller, Rikke S.; Weckhuysen, Sarah; Chipaux, Mathilde; Marsan, Elise; Taly, Valerie; Bebin, E. Martina; Hiatt, Susan M.; Prokop, Jeremy W.; Bowling, Kevin M.; Mei, Davide; Conti, Valerio; de la Grange, Pierre; Ferrand-Sorbets, Sarah; Dorfmüller, Georg; Lambrecq, Virginie; Larsen, Line H.G.; Leguern, Eric; Guerrini, Renzo; Rubboli, Guido; Cooper, Gregory M.

    2016-01-01

    Objective: To assess the prevalence of somatic MTOR mutations in focal cortical dysplasia (FCD) and of germline MTOR mutations in a broad range of epilepsies. Methods: We collected 20 blood-brain paired samples from patients with FCD and searched for somatic variants using deep-targeted gene panel sequencing. Germline mutations in MTOR were assessed in a French research cohort of 93 probands with focal epilepsies and in a diagnostic Danish cohort of 245 patients with a broad range of epilepsies. Data sharing among collaborators allowed us to ascertain additional germline variants in MTOR. Results: We detected recurrent somatic variants (p.Ser2215Phe, p.Ser2215Tyr, and p.Leu1460Pro) in the MTOR gene in 37% of participants with FCD II and showed histologic evidence for activation of the mTORC1 signaling cascade in brain tissue. We further identified 5 novel de novo germline missense MTOR variants in 6 individuals with a variable phenotype from focal, and less frequently generalized, epilepsies without brain malformations, to macrocephaly, with or without moderate intellectual disability. In addition, an inherited variant was found in a mother–daughter pair with nonlesional autosomal dominant nocturnal frontal lobe epilepsy. Conclusions: Our data illustrate the increasingly important role of somatic mutations of the MTOR gene in FCD and germline mutations in the pathogenesis of focal epilepsy syndromes with and without brain malformation or macrocephaly. PMID:27830187

  16. Germline and somatic mutations in the MTOR gene in focal cortical dysplasia and epilepsy.

    PubMed

    Møller, Rikke S; Weckhuysen, Sarah; Chipaux, Mathilde; Marsan, Elise; Taly, Valerie; Bebin, E Martina; Hiatt, Susan M; Prokop, Jeremy W; Bowling, Kevin M; Mei, Davide; Conti, Valerio; de la Grange, Pierre; Ferrand-Sorbets, Sarah; Dorfmüller, Georg; Lambrecq, Virginie; Larsen, Line H G; Leguern, Eric; Guerrini, Renzo; Rubboli, Guido; Cooper, Gregory M; Baulac, Stéphanie

    2016-12-01

    To assess the prevalence of somatic MTOR mutations in focal cortical dysplasia (FCD) and of germline MTOR mutations in a broad range of epilepsies. We collected 20 blood-brain paired samples from patients with FCD and searched for somatic variants using deep-targeted gene panel sequencing. Germline mutations in MTOR were assessed in a French research cohort of 93 probands with focal epilepsies and in a diagnostic Danish cohort of 245 patients with a broad range of epilepsies. Data sharing among collaborators allowed us to ascertain additional germline variants in MTOR. We detected recurrent somatic variants (p.Ser2215Phe, p.Ser2215Tyr, and p.Leu1460Pro) in the MTOR gene in 37% of participants with FCD II and showed histologic evidence for activation of the mTORC1 signaling cascade in brain tissue. We further identified 5 novel de novo germline missense MTOR variants in 6 individuals with a variable phenotype from focal, and less frequently generalized, epilepsies without brain malformations, to macrocephaly, with or without moderate intellectual disability. In addition, an inherited variant was found in a mother-daughter pair with nonlesional autosomal dominant nocturnal frontal lobe epilepsy. Our data illustrate the increasingly important role of somatic mutations of the MTOR gene in FCD and germline mutations in the pathogenesis of focal epilepsy syndromes with and without brain malformation or macrocephaly.

  17. CASP9 Germline Mutation in a Family with Multiple Brain Tumors.

    PubMed

    Ronellenfitsch, Michael W; Ji Eun, Oh; Satomi, Kaishi; Sumi, Koichiro; Harter, Patrick N; Steinbach, Joachim P; Felsberg, Jörg; Capper, David; Voegele, Catherine; Durand, Geoffroy; McKay, James; Le Calvez-Kelm, Florence; Schittenhelm, Jens; Klink, Barbara; Mittelbronn, Michel; Ohgaki, Hiroko

    2016-12-09

    We report a novel CASP9 germline mutation that may increase susceptibility to the development of brain tumors. We identified this mutation in a family in which three brain tumors had developed within three generations, including two anaplastic astrocytomas occurring in cousins. The cousins were diagnosed at similar ages (29 and 31 years), and their tumors showed similar histological features. Genetic analysis revealed somatic IDH1 and TP53 mutations in both tumors. However, no germline TP53 mutations were detected, despite the fact that this family fulfills the criteria of Li-Fraumeni-like syndrome. Whole exome sequencing revealed a germline stop-gain mutation (R65X) in the CASP9 gene, which encodes caspase-9, a key molecule for the p53-dependent mitochondrial death pathway. This mutation was also detected in DNA extracted from blood samples from the two siblings who were each a parent of one of the affected cousins. Caspase-9 immunohistochemistry showed the absence of caspase-9 immunoreactivity in the anaplastic astrocytomas and normal brain tissues of the cousins. These observations suggest that CASP9 germline mutations may have played a role at least in part to the susceptibility of development of gliomas in this Li-Fraumeni-like family lacking a TP53 germline mutation. This article is protected by copyright. All rights reserved.

  18. Pan-cancer analysis reveals technical artifacts in TCGA germline variant calls.

    PubMed

    Buckley, Alexandra R; Standish, Kristopher A; Bhutani, Kunal; Ideker, Trey; Lasken, Roger S; Carter, Hannah; Harismendy, Olivier; Schork, Nicholas J

    2017-06-12

    Cancer research to date has largely focused on somatically acquired genetic aberrations. In contrast, the degree to which germline, or inherited, variation contributes to tumorigenesis remains unclear, possibly due to a lack of accessible germline variant data. Here we called germline variants on 9618 cases from The Cancer Genome Atlas (TCGA) database representing 31 cancer types. We identified batch effects affecting loss of function (LOF) variant calls that can be traced back to differences in the way the sequence data were generated both within and across cancer types. Overall, LOF indel calls were more sensitive to technical artifacts than LOF Single Nucleotide Variant (SNV) calls. In particular, whole genome amplification of DNA prior to sequencing led to an artificially increased burden of LOF indel calls, which confounded association analyses relating germline variants to tumor type despite stringent indel filtering strategies. The samples affected by these technical artifacts include all acute myeloid leukemia and practically all ovarian cancer samples. We demonstrate how technical artifacts induced by whole genome amplification of DNA can lead to false positive germline-tumor type associations and suggest TCGA whole genome amplified samples be used with caution. This study draws attention to the need to be sensitive to problems associated with a lack of uniformity in data generation in TCGA data.

  19. The C. elegans adult male germline: stem cells and sexual dimorphism

    PubMed Central

    Morgan, Dyan E.; Crittenden, Sarah L.; Kimble, Judith

    2010-01-01

    The hermaphrodite C. elegans germline has become a classic model for stem cell regulation, but the male C. elegans germline has been largely neglected. This work provides a cellular analysis of the adult C. elegans male germline, focusing on its predicted stem cell region in the distal gonad. The goals of this study were two-fold: to establish the C. elegans male germline as a stem cell model and to identify sex-specific traits of potential relevance to the sperm/oocyte decision. Our results support two major conclusions. First, adult males do indeed possess a population of germline stem cells (GSCs) with properties similar to those of hermaphrodite GSCs (lack of cell cycle quiescence, lack of reproducibly oriented divisions). Second, germ cells in the mitotic region, including those most distal within the niche, exhibit sex-specific behaviors (e.g. cell cycle length) and therefore have acquired sexual identity. Previous studies demonstrated that some germ cells are not committed to a sperm or oocyte cell fate, even in adults. We propose that germ cells can acquire sexual identity without being committed to a sperm or oocyte cell fate. PMID:20659446

  20. 75 FR 78246 - Medicare Program; Re-Chartering of the Advisory Panel on Ambulatory Payment Classification (APC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-15

    ... deal with the following issues: Addressing whether procedures within an APC group are similar both... new technology APCs to clinical APCs). Evaluating APC group weights. Reviewing packaging the cost of... methodology for packaging and the impact of packaging on APC group structure and payment. Removing...

  1. Identification of Novel Human Cdt1-binding Proteins by a Proteomics Approach: Proteolytic Regulation by APC/CCdh1

    PubMed Central

    Sugimoto, Nozomi; Kitabayashi, Issay; Osano, Satoko; Tatsumi, Yasutoshi; Yugawa, Takashi; Narisawa-Saito, Mako; Matsukage, Akio; Kiyono, Tohru

    2008-01-01

    In mammalian cells, Cdt1 activity is strictly controlled by multiple independent mechanisms, implying that it is central to the regulation of DNA replication during the cell cycle. In fact, unscheduled Cdt1 hyperfunction results in rereplication and/or chromosomal damage. Thus, it is important to understand its function and regulations precisely. We sought to comprehensively identify human Cdt1-binding proteins by a combination of Cdt1 affinity chromatography and liquid chromatography and tandem mass spectrometry analysis. Through this approach, we could newly identify 11 proteins, including subunits of anaphase-promoting complex/cyclosome (APC/C), SNF2H and WSTF, topoisomerase I and IIα, GRWD1/WDR28, nucleophosmin/nucleoplasmin, and importins. In vivo interactions of Cdt1 with APC/CCdh1, SNF2H, topoisomerase I and IIα, and GRWD1/WDR28 were confirmed by coimmunoprecipitation assays. A further focus on APC/CCdh1 indicated that this ubiquitin ligase controls the levels of Cdt1 during the cell cycle via three destruction boxes in the Cdt1 N-terminus. Notably, elimination of these destruction boxes resulted in induction of strong rereplication and chromosomal damage. Thus, in addition to SCFSkp2 and cullin4-based ubiquitin ligases, APC/CCdh1 is a third ubiquitin ligase that plays a crucial role in proteolytic regulation of Cdt1 in mammalian cells. PMID:18162579

  2. Piwi Is a Key Regulator of Both Somatic and Germline Stem Cells in the Drosophila Testis.

    PubMed

    Gonzalez, Jacob; Qi, Hongying; Liu, Na; Lin, Haifan

    2015-07-07

    The Piwi-piRNA pathway is well known for its germline function, yet its somatic role remains elusive. We show here that Piwi is required autonomously not only for germline stem cell (GSC) but also for somatic cyst stem cell (CySC) maintenance in the Drosophila testis. Reducing Piwi activity in the testis caused defects in CySC differentiation. Accompanying this, GSC daughters expanded beyond the vicinity of the hub but failed to differentiate further. Moreover, Piwi deficient in nuclear localization caused similar defects in somatic and germ cell differentiation, which was rescued by somatic Piwi expression. To explore the underlying molecular mechanism, we identified Piwi-bound piRNAs that uniquely map to a gene key for gonadal development, Fasciclin 3, and demonstrate that Piwi regulates its expression in somatic cyst cells. Our work reveals the cell-autonomous function of Piwi in both somatic and germline stem cell types, with somatic function possibly via its epigenetic mechanism.

  3. Transgenerational effects of proton beam irradiation on Caenorhabditis elegans germline apoptosis.

    PubMed

    Min, Hyemin; Sung, Minhee; Son, Miseol; Kawasaki, Ichiro; Shim, Yhong-Hee

    2017-08-26

    When treating cancer using radiation therapy, it is critical to increase patient survival rates and to reduce side effects. In this respect, proton beam radiation treatment performs better than other radiation treatments because of its high target specificity. However, complications still remain after proton beam radiation treatment. Among them, the risk to progeny after irradiation of their parents is a major concern. In this study, we analyzed the transgenerational effects of proton beam irradiation using the model organism Caenorhabditis. elegans. We found that germline apoptosis increased after proton beam irradiation and its effects were sustained transgenerationally. Moreover, we identified that a germline-specific histone methyltransferase component, SET-2, has a critical role in transmitting the transgenerational effect on germline apoptosis to the next generation after proton beam irradiation. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Xeroderma Pigmentosum: Low Prevalence of Germline XPA Mutations in a Brazilian XP Population

    PubMed Central

    Santiago, Karina Miranda; França de Nóbrega, Amanda; Rocha, Rafael Malagoli; Rogatto, Silvia Regina; Achatz, Maria Isabel

    2015-01-01

    Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by DNA repair defects that cause photophobia, sunlight-induced cancers, and neurodegeneration. Prevalence of germline mutations in the nucleotide excision repair gene XPA vary significantly in different populations. No Brazilian patients have been reported to carry a germline mutation in this gene. In this study, the germline mutational status of XPA was determined in Brazilian patients exhibiting major clinical features of XP syndrome. The study was conducted on 27 unrelated patients from select Brazilian families. A biallelic inactivating transition mutation c.619C>T (p.Arg207Ter) was identified in only one patient with a history of neurological impairment and mild skin abnormalities. These findings suggest that XP syndrome is rarely associated with inherited disease-causing XPA mutations in the Brazilian population. Additionally, this report demonstrates the effectiveness of genotype-phenotype correlation as a valuable tool to guide direct genetic screening. PMID:25913378

  5. Xeroderma pigmentosum: low prevalence of germline XPA mutations in a Brazilian XP population.

    PubMed

    Santiago, Karina Miranda; França de Nóbrega, Amanda; Rocha, Rafael Malagoli; Rogatto, Silvia Regina; Achatz, Maria Isabel

    2015-04-22

    Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by DNA repair defects that cause photophobia, sunlight-induced cancers, and neurodegeneration. Prevalence of germline mutations in the nucleotide excision repair gene XPA vary significantly in different populations. No Brazilian patients have been reported to carry a germline mutation in this gene. In this study, the germline mutational status of XPA was determined in Brazilian patients exhibiting major clinical features of XP syndrome. The study was conducted on 27 unrelated patients from select Brazilian families. A biallelic inactivating transition mutation c.619C>T (p.Arg207Ter) was identified in only one patient with a history of neurological impairment and mild skin abnormalities. These findings suggest that XP syndrome is rarely associated with inherited disease-causing XPA mutations in the Brazilian population. Additionally, this report demonstrates the effectiveness of genotype-phenotype correlation as a valuable tool to guide direct genetic screening.

  6. Mosaic parental germline mutations causing recurrent forms of malformations of cortical development.

    PubMed

    Zillhardt, Julia Lauer; Poirier, Karine; Broix, Loïc; Lebrun, Nicolas; Elmorjani, Adrienne; Martinovic, Jelena; Saillour, Yoann; Muraca, Giuseppe; Nectoux, Juliette; Bessieres, Bettina; Fallet-Bianco, Catherine; Lyonnet, Stanislas; Dulac, Olivier; Odent, Sylvie; Rejeb, Imen; Ben Jemaa, Lamia; Rivier, Francois; Pinson, Lucile; Geneviève, David; Musizzano, Yuri; Bigi, Nicole; Leboucq, Nicolas; Giuliano, Fabienne; Philip, Nicole; Vilain, Catheline; Van Bogaert, Patrick; Maurey, Hélène; Beldjord, Cherif; Artiguenave, François; Boland, Anne; Olaso, Robert; Masson, Cécile; Nitschké, Patrick; Deleuze, Jean-François; Bahi-Buisson, Nadia; Chelly, Jamel

    2016-04-01

    To unravel missing genetic causes underlying monogenic disorders with recurrence in sibling, we explored the hypothesis of parental germline mosaic mutations in familial forms of malformation of cortical development (MCD). Interestingly, four families with parental germline variants, out of 18, were identified by whole-exome sequencing (WES), including a variant in a new candidate gene, syntaxin 7. In view of this high frequency, revision of diagnostic strategies and reoccurrence risk should be considered not only for the recurrent forms, but also for the sporadic cases of MCD.

  7. Germ-Line Recombination Activity of the Widely Used hGFAP-Cre and Nestin-Cre Transgenes

    PubMed Central

    Zhang, Jiong; Dublin, Pavel; Griemsmann, Stephanie; Klein, Alexandra; Brehm, Ralph; Bedner, Peter; Fleischmann, Bernd K.; Steinhäuser, Christian; Theis, Martin

    2013-01-01

    Herein we demonstrate with PCR, immunodetection and reporter gene approaches that the widely used human Glial Fibrillary Acidic Protein (hGFAP)-Cre transgene exhibits spontaneous germ-line recombination activity in leading to deletion in brain, heart and tail tissue with high frequency. The ectopic activity of hGFAP-Cre requires a rigorous control. We likewise observed that a second widely used nestin-Cre transgene shows germ-line deletion. Here we describe procedures to identify mice with germ-line recombination mediated by the hGFAP-Cre and nestin-Cre transgenes. Such control is essential to avoid pleiotropic effects due to germ-line deletion of loxP-flanked target genes and to maintain the CNS-restricted deletion status in transgenic mouse colonies. PMID:24349371

  8. Caenorhabditis elegans lin-35/Rb, efl-1/E2F and other synthetic multivulva genes negatively regulate the anaphase-promoting complex gene mat-3/APC8.

    PubMed Central

    Garbe, David; Doto, Jeffrey B; Sundaram, Meera V

    2004-01-01

    Retinoblastoma (Rb)/E2F complexes repress expression of many genes important for G(1)-to-S transition, but also appear to regulate gene expression at other stages of the cell cycle. In C. elegans, lin-35/Rb and other synthetic Multivulva (SynMuv) group B genes function redundantly with other sets of genes to regulate G(1)/S progression, vulval and pharyngeal differentiation, and other unknown processes required for viability. Here we show that lin-35/Rb, efl-1/E2F, and other SynMuv B genes negatively regulate a component of the anaphase-promoting complex or cyclosome (APC/C). The APC/C is a multisubunit complex that promotes metaphase-to-anaphase progression and G(1) arrest by targeting different substrates for ubiquitination and proteasome-mediated destruction. The C. elegans APC/C gene mat-3/APC8 has been defined by temperature-sensitive embryonic lethal alleles that strongly affect germline meiosis and mitosis but only weakly affect somatic development. We describe severe nonconditional mat-3 alleles and a hypomorphic viable allele (ku233), all of which affect postembryonic cell divisions including those of the vulval lineage. The ku233 lesion is located outside of the mat-3 coding region and reduces mat-3 mRNA expression. Loss-of-function alleles of lin-35/Rb and other SynMuv B genes suppress mat-3(ku233) defects by restoring mat-3 mRNA to wild-type levels. Therefore, Rb/E2F complexes appear to repress mat-3 expression. PMID:15238519

  9. Caenorhabditis elegans lin-35/Rb, efl-1/E2F and other synthetic multivulva genes negatively regulate the anaphase-promoting complex gene mat-3/APC8.

    PubMed

    Garbe, David; Doto, Jeffrey B; Sundaram, Meera V

    2004-06-01

    Retinoblastoma (Rb)/E2F complexes repress expression of many genes important for G(1)-to-S transition, but also appear to regulate gene expression at other stages of the cell cycle. In C. elegans, lin-35/Rb and other synthetic Multivulva (SynMuv) group B genes function redundantly with other sets of genes to regulate G(1)/S progression, vulval and pharyngeal differentiation, and other unknown processes required for viability. Here we show that lin-35/Rb, efl-1/E2F, and other SynMuv B genes negatively regulate a component of the anaphase-promoting complex or cyclosome (APC/C). The APC/C is a multisubunit complex that promotes metaphase-to-anaphase progression and G(1) arrest by targeting different substrates for ubiquitination and proteasome-mediated destruction. The C. elegans APC/C gene mat-3/APC8 has been defined by temperature-sensitive embryonic lethal alleles that strongly affect germline meiosis and mitosis but only weakly affect somatic development. We describe severe nonconditional mat-3 alleles and a hypomorphic viable allele (ku233), all of which affect postembryonic cell divisions including those of the vulval lineage. The ku233 lesion is located outside of the mat-3 coding region and reduces mat-3 mRNA expression. Loss-of-function alleles of lin-35/Rb and other SynMuv B genes suppress mat-3(ku233) defects by restoring mat-3 mRNA to wild-type levels. Therefore, Rb/E2F complexes appear to repress mat-3 expression.

  10. Male Germline Control of Transposable Elements1

    PubMed Central

    Bao, Jianqiang; Yan, Wei

    2012-01-01

    ABSTRACT Repetitive sequences, especially transposon-derived interspersed repetitive elements, account for a large fraction of the genome in most eukaryotes. Despite the repetitive nature, these transposable elements display quantitative and qualitative differences even among species of the same lineage. Although transposable elements contribute greatly as a driving force to the biological diversity during evolution, they can induce embryonic lethality and genetic disorders as a result of insertional mutagenesis and genomic rearrangement. Temporary relaxation of the epigenetic control of retrotransposons during early germline development opens a risky window that can allow retrotransposons to escape from host constraints and to propagate abundantly in the host genome. Because germline mutations caused by retrotransposon activation are heritable and thus can be deleterious to the offspring, an adaptive strategy has evolved in host cells, especially in the germline. In this review, we will attempt to summarize general defense mechanisms deployed by the eukaryotic genome, with an emphasis on pathways utilized by the male germline to confer retrotransposon silencing. PMID:22357546

  11. Silencing transposable elements in the Drosophila germline.

    PubMed

    Yang, Fu; Xi, Rongwen

    2017-02-01

    Transposable elements or transposons are DNA pieces that can move around within the genome and are, therefore, potential threat to genome stability and faithful transmission of the genetic information in the germline. Accordingly, self-defense mechanisms have evolved in the metazoan germline to silence transposons, and the primary mechanism requires the germline-specific non-coding small RNAs, named Piwi-interacting RNA (piRNAs), which are in complex with Argonaute family of PIWI proteins (the piRNA-RISC complexes), to silence transposons. piRNA-mediated transposon silencing occurs at both transcriptional and post-transcriptional levels. With the advantages of genetic manipulation and advances of sequencing technology, much progress has been made on the molecular mechanisms of piRNA-mediated transposon silencing in Drosophila melanogaster, which will be the focus of this review. Because piRNA-mediated transposon silencing is evolutionarily conserved in metazoan, model organisms, such as Drosophila, will continue to be served as pioneer systems towards the complete understanding of transposon silencing in the metazoan germline.

  12. Germline and somatic DNA methylation and epigenetic regulation of KILLIN in renal cell carcinoma

    PubMed Central

    Bennett, Kristi L.; Campbell, Rebecca; Ganapathi, Shireen; Zhou, Ming; Rini, Brian; Ganapathi, Ram; Neumann, Hartmut P.H.; Eng, Charis

    2011-01-01

    We recently identified germline methylation of KILLIN, a novel p53-regulated tumor suppressor proximal to PTEN, in >1/3 Cowden or Cowden syndrome-like (CS/CSL) individuals who are PTEN mutation negative. Individuals with germline KILLIN methylation had increased risks of renal cell carcinoma (RCC) over those with PTEN mutations. Therefore, we tested the hypothesis that KILLIN may be a RCC susceptibility gene, silenced by germline methylation. We found germline hypermethylation by combined bisulfite restriction analysis (COBRA) in at least one of the four CpG-rich regions in 23/41 (56%) RCC patients compared to 0/50 controls (P<0.0001). Of the 23, 11 (48%) demonstrated methylation in the -598bp to -890bp region in respect to the KILLIN transcription start site. Furthermore, 19 of 20 advanced RCC showed somatic hypermethylation upstream of KILLIN, with the majority hypermethylated at more than one CpG island (13/19 vs 3/23 with germline methylation, p<0.0001). qRT-PCR revealed that methylation significantly downregulates KILLIN expression (P=0.05), and demethylation treatment by 5-aza-2’deoxycytidine significantly increased KILLIN expression in all RCC cell lines while only increasing PTEN expression in one line. Furthermore, targeted in vitro methylation revealed a significant decrease in KILLIN promoter activity only. These data reveal differential epigenetic regulation by DNA promoter methylation of this bidirectional promoter. In summary, we have identified KILLIN as a potential novel cancer predisposition gene for nonsyndromic ccRCC, and the epigenetic mechanism of KILLIN inactivation in both the germline and somatic setting suggests the potential for treatment with demethylating agents. PMID:21584899

  13. Elucidating the molecular basis of MSH2-deficient tumors by combined germline and somatic analysis.

    PubMed

    Vargas-Parra, Gardenia M; González-Acosta, Maribel; Thompson, Bryony A; Gómez, Carolina; Fernández, Anna; Dámaso, Estela; Pons, Tirso; Morak, Monika; Del Valle, Jesús; Iglesias, Silvia; Velasco, Àngela; Solanes, Ares; Sanjuan, Xavier; Padilla, Natàlia; de la Cruz, Xavier; Valencia, Alfonso; Holinski-Feder, Elke; Brunet, Joan; Feliubadaló, Lídia; Lázaro, Conxi; Navarro, Matilde; Pineda, Marta; Capellá, Gabriel

    2017-10-01

    In a proportion of patients presenting mismatch repair (MMR)-deficient tumors, no germline MMR mutations are identified, the so-called Lynch-like syndrome (LLS). Recently, MMR-deficient tumors have been associated with germline mutations in POLE and MUTYH or double somatic MMR events. Our aim was to elucidate the molecular basis of MSH2-deficient LS-suspected cases using a comprehensive analysis of colorectal cancer (CRC)-associated genes at germline and somatic level. Fifty-eight probands harboring MSH2-deficient tumors were included. Germline mutational analysis of MSH2 (including EPCAM deletions) and MSH6 was performed. Pathogenicity of MSH2 variants was assessed by RNA analysis and multifactorial likelihood calculations. MSH2 cDNA and methylation of MSH2 and MSH6 promoters were studied. Matched blood and tumor DNA were analyzed using a customized next generation sequencing panel. Thirty-five individuals were carriers of pathogenic or probably pathogenic variants in MSH2 and EPCAM. Five patients harbored 4 different MSH2 variants of unknown significance (VUS) and one had 2 novel MSH6 promoter VUS. Pathogenicity assessment allowed the reclassification of the 4 MSH2 VUS and 6 probably pathogenic variants as pathogenic mutations, enabling a total of 40 LS diagnostics. Predicted pathogenic germline variants in BUB1, SETD2, FAN1 and MUTYH were identified in 5 cases. Three patients had double somatic hits in MSH2 or MSH6, and another 2 had somatic alterations in other MMR genes and/or proofreading polymerases. In conclusion, our comprehensive strategy combining germline and somatic mutational status of CRC-associated genes by means of a subexome panel allows the elucidation of up to 86% of MSH2-deficient suspected LS tumors. © 2017 UICC.

  14. Phosphorylation and dephosphorylation regulate APC/CCdh1 substrate degradation

    PubMed Central

    Simpson-Lavy, Kobi J; Zenvirth, Drora; Brandeis, Michael

    2015-01-01

    The Anaphase Promoting Complex/Cyclosome (APC/C) ubiquitin ligase activated by its G1 specific adaptor protein Cdh1 is a major regulator of the cell cycle. The APC/CCdh1 mediates degradation of dozens of proteins, however, the kinetics and requirements for their degradation are largely unknown. We demonstrate that overexpression of the constitutive active CDH1m11 mutant that is not inhibited by phosphorylation results in mitotic exit in the absence of the FEAR and MEN pathways, and DNA re-replication in the absence of Cdc7 activity. This mode of mitotic exit also reveals additional requirements for APC/CCdh1 substrate degradation, which for some substrates such as Pds1 or Clb5 is dephosphorylation, but for others such as Cdc5 is phosphorylation. PMID:26252546

  15. Functional redundancy between Apc and Apc2 regulates tissue homeostasis and prevents tumourigenesis in murine mammary epithelium

    PubMed Central

    Daly, Carl S.; Shaw, Paul; Ordonez, Liliana D.; Williams, Geraint T.; Quist, Jelmar; Grigoriadis, Anita; Van Es, Johan H.; Clevers, Hans; Clarke, Alan R.; Reed, Karen R.

    2016-01-01

    Aberrant Wnt signaling within breast cancer is associated with poor prognosis, but regulation of this pathway in breast tissue remains poorly understood and the consequences of immediate or long-term dysregulation remain elusive. The exact contribution of the Wnt-regulating proteins APC and APC2 in the pathogenesis of human breast cancer are ill-defined, but our analysis of publically available array datasets indicates that tumors with concomitant low expression of both proteins occurs more frequently in the ‘triple negative’ phenotype, which is a subtype of breast cancer with particularly poor prognosis. We have used mouse transgenics to delete Apc and/or Apc2 from mouse mammary epithelium to elucidate the significance of these proteins in mammary homeostasis and delineate their influences on Wnt signaling and tumourigenesis. Loss of either protein alone failed to affect Wnt signaling levels or tissue homeostasis. Strikingly, concomitant loss led to local disruption of β-catenin status, disruption in epithelial integrity, cohesion and polarity, increased cell division and a distinctive form of ductal hyperplasia with ‘squamoid’ ghost cell nodules in young animals. Upon aging, the development of Wnt activated mammary carcinomas with squamous differentiation was accompanied by a significantly reduced survival. This novel Wnt driven mammary tumour model highlights the importance of functional redundancies existing between the Apc proteins both in normal homeostasis and in tumorigenesis. PMID:27694902

  16. A Functional Genomic Screen for Evolutionarily Conserved Genes Required for Lifespan and Immunity in Germline-Deficient C. elegans

    PubMed Central

    Sinha, Amit; Rae, Robbie

    2014-01-01

    The reproductive system regulates lifespan in insects, nematodes and vertebrates. In Caenorhabditis elegans removal of germline increases lifespan by 60% which is dependent upon insulin signaling, nuclear hormone signaling, autophagy and fat metabolism and their microRNA-regulators. Germline-deficient C. elegans are also more resistant to various bacterial pathogens but the underlying molecular mechanisms are largely unknown. Firstly, we demonstrate that previously identified genes that regulate the extended lifespan of germline-deficient C. elegans (daf-2, daf-16, daf-12, tcer-1, mir-7.1 and nhr-80) are also essential for resistance to the pathogenic bacterium Xenorhabdus nematophila. We then use a novel unbiased approach combining laser cell ablation, whole genome microarrays, RNAi screening and exposure to X. nematophila to generate a comprehensive genome-wide catalog of genes potentially required for increased lifespan and innate immunity in germline-deficient C. elegans. We find 3,440 genes to be upregulated in C. elegans germline-deficient animals in a gonad dependent manner, which are significantly enriched for genes involved in insulin signaling, fatty acid desaturation, translation elongation and proteasome complex function. Using RNAi against a subset of 150 candidate genes selected from the microarray results, we show that the upregulated genes such as transcription factor DAF-16/FOXO, the PTEN homolog lipid phosphatase DAF-18 and several components of the proteasome complex (rpn-6.1, rpn-7, rpn-9, rpn-10, rpt-6, pbs-3 and pbs-6) are essential for both lifespan and immunity of germline deficient animals. We also identify a novel role for genes including par-5 and T12G3.6 in both lifespan-extension and increased survival on X. nematophila. From an evolutionary perspective, most of the genes differentially expressed in germline deficient C. elegans also show a conserved expression pattern in germline deficient Pristionchus pacificus, a nematode species

  17. Germline genomic variations associated with childhood acute lymphoblastic leukemia

    PubMed Central

    Treviño, Lisa R.; Yang, Wenjian; French, Deborah; Hunger, Stephen; Carroll, William L.; Devidas, Meenakshi; Willman, Cheryl; Neale, Geoffrey; Downing, James; Raimondi, Susana; Pui, Ching-Hon; Evans, William E.; Relling, Mary V.

    2009-01-01

    We identified germline single nucleotide polymorphisms (SNPs) associated with childhood acute lymphoblastic leukemia (ALL) and its subtypes. Using the Affymetrix 500K Mapping array and publicly available genotypes, we identified 18 SNPs whose allele frequency differed (P<1×10−5) between a pediatric ALL population (n=317) and non-ALL controls (n=17,958). Six of these SNPs differed (P≤0.05) in allele frequency among four ALL subtypes. Two SNPs in ARID5B not only differed between ALL and non-ALL groups (rs10821936, P=1.4×10−15, odds ratio[OR]=1.91; rs10994982, P=5.7×10−9, OR=1.62) but also distinguished B-hyperdiploid ALL from other subtypes (rs10821936, P=1.62 ×10−5, OR=2.17; rs10994982, P=0.003, OR 1.72). These ARID5B SNPs also distinguished B-hyperdiploid ALL from other subtypes in an independent validation cohort (n=124 children with ALL) (P=0.003 and P=0.0008, OR 2.45 and 2.86, respectively) and were associated with methotrexate accumulation and gene expression pattern in leukemic lymphoblasts. We conclude that germline genomic variations affect susceptibility to and characteristics of specific ALL subtypes. PMID:19684603

  18. A new conditional Apc-mutant mouse model for colorectal cancer.

    PubMed

    Robanus-Maandag, Els C; Koelink, Pim J; Breukel, Cor; Salvatori, Daniela C F; Jagmohan-Changur, Shantie C; Bosch, Cathy A J; Verspaget, Hein W; Devilee, Peter; Fodde, Riccardo; Smits, Ron

    2010-05-01

    Mutations of the adenomatous polyposis coli (APC) gene predispose individuals to familial adenomatous polyposis (FAP), characterized by multiple tumours in the large intestine. Most mouse models heterozygous for truncating mutant Apc alleles mimic FAP, however, the intestinal tumours occur mainly in the small intestine. To model large intestinal tumours, we generated a new conditional Apc-mutant allele, Apc(15lox), with exon 15 flanked by loxP sites. Similar survival of Apc(1638N/15lox) and Apc(1638N/+) mice indicated that the normal function of Apc was not impaired by the loxP sites. Deletion of exon 15, encoding nearly all functional Apc domains and containing the polyadenylation signal, resulted in a mutant allele expressing low levels of a 74 kDa truncated Apc protein. Germ line Cre-mediated deletion of exon 15 resulted in Apc(Delta15/+) mice, showing a severe Apc(Min/+)-like phenotype characterized by multiple tumours in the small intestine and early lethality. In contrast, conditional Cre-mediated deletion of exon 15 specifically directed to the epithelia of distal small and large intestine of FabplCre;Apc(15lox/+) mice led to longer survival and to tumours that developed predominantly in the large intestine, mimicking human FAP-associated colorectal cancer and sporadic colorectal cancer. We conclude that the FabplCre;Apc(15lox/+) mouse should be an attractive model for studies on prevention and treatment of colorectal cancer.

  19. Prevalence and Spectrum of Germline Cancer Susceptibility Gene Mutations Among Patients With Early-Onset Colorectal Cancer.

    PubMed

    Pearlman, Rachel; Frankel, Wendy L; Swanson, Benjamin; Zhao, Weiqiang; Yilmaz, Ahmet; Miller, Kristin; Bacher, Jason; Bigley, Christopher; Nelsen, Lori; Goodfellow, Paul J; Goldberg, Richard M; Paskett, Electra; Shields, Peter G; Freudenheim, Jo L; Stanich, Peter P; Lattimer, Ilene; Arnold, Mark; Liyanarachchi, Sandya; Kalady, Matthew; Heald, Brandie; Greenwood, Carla; Paquette, Ian; Prues, Marla; Draper, David J; Lindeman, Carolyn; Kuebler, J Philip; Reynolds, Kelly; Brell, Joanna M; Shaper, Amy A; Mahesh, Sameer; Buie, Nicole; Weeman, Kisa; Shine, Kristin; Haut, Mitchell; Edwards, Joan; Bastola, Shyamal; Wickham, Karen; Khanduja, Karamjit S; Zacks, Rosemary; Pritchard, Colin C; Shirts, Brian H; Jacobson, Angela; Allen, Brian; de la Chapelle, Albert; Hampel, Heather

    2017-04-01

    Hereditary cancer syndromes infer high cancer risks and require intensive cancer surveillance, yet the prevalence and spectrum of these conditions among unselected patients with early-onset colorectal cancer (CRC) is largely undetermined. To determine the frequency and spectrum of cancer susceptibility gene mutations among patients with early-onset CRC. Overall, 450 patients diagnosed with colorectal cancer younger than 50 years were prospectively accrued from 51 hospitals into the Ohio Colorectal Cancer Prevention Initiative from January 1, 2013, to June 20, 2016. Mismatch repair (MMR) deficiency was determined by microsatellite instability and/or immunohistochemistry. Germline DNA was tested for mutations in 25 cancer susceptibility genes using next-generation sequencing. Mutation prevalence and spectrum in patients with early-onset CRC was determined. Clinical characteristics were assessed by mutation status. In total 450 patients younger than 50 years were included in the study, and 75 gene mutations were found in 72 patients (16%). Forty-eight patients (10.7%) had MMR-deficient tumors, and 40 patients (83.3%) had at least 1 gene mutation: 37 had Lynch syndrome (13, MLH1 [including one with constitutional MLH1 methylation]; 16, MSH2; 1, MSH2/monoallelic MUTYH; 2, MSH6; 5, PMS2); 1 patient had the APC c.3920T>A, p.I1307K mutation and a PMS2 variant; 9 patients (18.8%) had double somatic MMR mutations (including 2 with germline biallelic MUTYH mutations); and 1 patient had somatic MLH1 methylation. Four hundred two patients (89.3%) had MMR-proficient tumors, and 32 patients (8%) had at least 1 gene mutation: 9 had mutations in high-penetrance CRC genes (5, APC; 1, APC/PMS2; 2, biallelic MUTYH; 1, SMAD4); 13 patients had mutations in high- or moderate-penetrance genes not traditionally associated with CRC (3, ATM; 1, ATM/CHEK2; 2, BRCA1; 4, BRCA2; 1, CDKN2A; 2, PALB2); 10 patients had mutations in low-penetrance CRC genes (3, APC c.3920T>A, p.I1307K; 7

  20. Original CIN: reviewing roles for APC in chromosome instability.

    PubMed

    Rusan, Nasser M; Peifer, Mark

    2008-06-02

    You may have seen the bumper sticker "Eve was framed." Thousands of years of being blamed for original sin and still many wonder, where's the evidence? Today, the tumor suppressor adenomatous polyposis coli (APC) may have the same complaint about accusations of a different type of CIN, chromosome instability. A series of recent papers, including three in this journal, propose that loss of APC function plays an important role in the CIN seen in many colon cancer cells. However, a closer look reveals a complex story that raises more questions than answers.

  1. The APC I1307K allele conveys a significant increased risk for cancer.

    PubMed

    Leshno, Ari; Shapira, Shiran; Liberman, Eliezer; Kraus, Sarah; Sror, Miri; Harlap-Gat, Amira; Avivi, Doran; Galazan, Lior; David, Maayan; Maharshak, Nitsan; Moanis, Serhan; Arber, Nadir; Moshkowitz, Menachem

    2016-03-15

    This study is the first attempt to evaluate the association between the APC I1307K variant and overall cancer risk. It is unique in both its large sample size and in the reliability of data in the control group. The findings described in this article have major implications in terms of identifying asymptomatic individuals who are at increased risk to harbor cancer and therefore targeted to be enrolled in specific early detection and prevention programs. The prevalence of the APC I1307K missense mutation among Ashkenazi Jews is ∼ 6%. Carriers are at an increased risk for colorectal neoplasia. In this study, we examined the association of this variant with non-colorectal cancers. Consecutive 13,013 healthy subjects who underwent screening at the Integrated Cancer Prevention Center between 2006 and 2014 were enrolled. This population was supplemented with 1,611 cancer patients from the same institution. Demographics, medical history, and pathological data were recorded. Mortality data were obtained from the Ministry of Health's registry. The prevalence of APC I1307K in cancer patients and healthy subjects was compared. The APC I1307K variant was detected in 189 (11.8%) cancer patients compared to 614 (4.7%) healthy subjects, reflecting an adjusted age and sex odds ratio (OR) of 2.53 (p < 0.0001). History of two or more cancer types was associated with a positive carrier prevalence (OR = 4.38 p < 0.0001). Males had significantly increased carrier prevalence in lung, urologic, pancreatic, and skin cancers. The carrier prevalence among females was significantly higher only in breast and skin cancers. Female carriers developed cancer at a significantly older age compared to non-carriers (average 62.7 years vs. 57.8, respectively, p = 0.027), had better survival rates (HR = 0.58, p = 0.022) and overall increased longevity (average age of death 78.8 vs. 70.4 years, respectively, p = 0.003). In conclusion, the APC I1307K variant is a reliable marker for overall cancer risk

  2. Creation of an engineered APC system to explore and optimize the presentation of immunodominant peptides of major allergens

    PubMed Central

    Rosskopf, Sandra; Jutz, Sabrina; Neunkirchner, Alina; Candia, Martín R.; Jahn-Schmid, Beatrice; Bohle, Barbara; Pickl, Winfried F.; Steinberger, Peter

    2016-01-01

    We have generated engineered APC to present immunodominant peptides derived from the major aero-allergens of birch and mugwort pollen, Bet v 1142–153 and Art v 125–36, respectively. Jurkat-based T cell reporter lines expressing the cognate allergen-specific T cell receptors were used to read out the presentation of allergenic peptides on the engineered APC. Different modalities of peptide loading and presentation on MHC class II molecules were compared. Upon exogenous loading with allergenic peptides, the engineered APC elicited a dose-dependent response in the reporter T cells and the presence of chemical loading enhancers strongly increased reporter activation. Invariant chain-based MHC class II targeting strategies of endogenously expressed peptides resulted in stronger activation of the reporters than exogenous loading. Moreover, we used Bet v 1 as model allergen to study the ability of K562 cells to present antigenic peptides derived from whole proteins either taken up or endogenously expressed as LAMP-1 fusion protein. In both cases the ability of these cells to process and present peptides derived from whole proteins critically depended on the expression of HLA-DM. We have identified strategies to achieve efficient presentation of allergenic peptides on engineered APC and demonstrate their use to stimulate T cells from allergic individuals. PMID:27539532

  3. APC/C(Cdh1) controls CtIP stability during the cell cycle and in response to DNA damage.

    PubMed

    Lafranchi, Lorenzo; de Boer, Harmen R; de Vries, Elisabeth G E; Ong, Shao-En; Sartori, Alessandro A; van Vugt, Marcel A T M

    2014-12-01

    Human cells have evolved elaborate mechanisms for responding to DNA damage to maintain genome stability and prevent carcinogenesis. For instance, the cell cycle can be arrested at different stages to allow time for DNA repair. The APC/C(C) (dh1) ubiquitin ligase mainly regulates mitotic exit but is also implicated in the DNA damage-induced G2 arrest. However, it is currently unknown whether APC/C(C) (dh1) also contributes to DNA repair. Here, we show that Cdh1 depletion causes increased levels of genomic instability and enhanced sensitivity to DNA-damaging agents. Using an integrated proteomics and bioinformatics approach, we identify CtIP, a DNA-end resection factor, as a novel APC/C(C) (dh1) target. CtIP interacts with Cdh1 through a conserved KEN box, mutation of which impedes ubiquitylation and downregulation of CtIP both during G1 and after DNA damage in G2. Finally, we find that abrogating the CtIP-Cdh1 interaction results in delayed CtIP clearance from DNA damage foci, increased DNA-end resection, and reduced homologous recombination efficiency. Combined, our results highlight the impact of APC/C(C) (dh1) on the maintenance of genome integrity and show that this is, at least partially, achieved by controlling CtIP stability in a cell cycle- and DNA damage-dependent manner.

  4. Targeted Apc;Twist Double-Mutant Mice: A New Model of Spontaneous Osteosarcoma That Mimics the Human Disease123

    PubMed Central

    Entz-Werlé, Natacha; Choquet, Philippe; Neuville, Agnès; Kuchler-Bopp, Sabine; Clauss, François; Danse, Jean-Marc; Simo-Noumbissie, Pauline; Guérin, Eric; Gaub, Marie-Pierre; Freund, Jean-Noel; Boehm, Nelly; Constantinesco, André; Lutz, Patrick; Guenot, Dominique; Perrin-Schmitt, Fabienne

    2010-01-01

    TWIST and adenomatosis polyposis coli (APC) are critical signaling factors in normal bone development. In previous studies examining a homogeneously treated cohort of pediatric osteosarcoma patients, we reported the frequent and concurrent loss of both TWIST and APC genes. On these bases, we created a related animal model to further explore the oncogenic cooperation between these two genes. We performed intercrosses between twist-null/+ and Apc1638N/+ mice and studied their progeny. The Apc1638N/+;twistnull/+ mice developed bone abnormalities observed by macroscopic skeletal analyses and in vivo imaging. Complementary histologic, cellular, and molecular analyses were used to characterize the identified bone tumors, including cell culture and immunofluorescence of bone differentiation markers. Spontaneous localized malignant bone tumors were frequently identified in Apc1638N/+;twist-null/+ mice by in vivo imaging evaluation and histologic analyses. These tumors possessed several features similar to those observed in human localized osteosarcomas. In particular, the murine tumors presented with fibroblastic, chondroblastic, and osteoblastic osteosarcoma histologies, as well as mixtures of these subtypes. In addition, cellular analyses and bone differentiation markers detected by immunofluorescence on tumor sections reproduced most murine and human osteosarcoma characteristics. For example, the early bone differentiation marker Runx2, interacting physically with hypophosphorylated pRb, was undetectable in these murine osteosarcomas, whereas phosphorylated retinoblastoma was abundant in the osteoblastic and chondroblastic tumor subtypes. These characteristics, similar to those observed in human osteosarcomas, indicated that our animal model may be a powerful tool to further understand the development of localized osteosarcoma. PMID:21151473

  5. Mesothelioma patients with germline BAP1 mutations have 7-fold improved long-term survival.

    PubMed

    Baumann, Francine; Flores, Erin; Napolitano, Andrea; Kanodia, Shreya; Taioli, Emanuela; Pass, Harvey; Yang, Haining; Carbone, Michele

    2015-01-01

    BRCA1-associated protein-1 (BAP1) mutations cause a new cancer syndrome, with a high rate of malignant mesothelioma (MM). Here, we tested the hypothesis that MM associated with germline BAP1 mutations has a better prognosis compared with sporadic MM. We compared survival among germline BAP1 mutation MM patients with that of all MM (N = 10 556) recorded in the United States Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 2010. We identified 23 MM patients--11 alive--with germline BAP1 mutations and available data on survival. Ten patients had peritoneal MM, ten pleural MM and three MM in both locations. Thirteen patients had one or more malignancies in addition to MM. Actuarial median survival for the MM patients with germline BAP1 mutations was 5 years, as compared with <1 year for the median survival in the United States SEER MM group. Five-year survival was 47%, 95% confidence interval (24-67%), as compared with 6.7% (6.2-7.3%) in the control SEER group. Analysis of the pooled cohort of germline BAP1 mutation MM showed that patients with peritoneal MM (median survival of 10 years, P = 0.0571), or with a second malignancy in addition to MM (median survival of 10 years, P = 0.0716), survived for a longer time compared with patients who only had pleural MM, or MM patients without a second malignancy, respectively. In conclusion, we found that MM patients with germline BAP1 mutations have an overall 7-fold increased long-term survival, independently of sex and age. Appropriate genetic counseling and clinical management should be considered for MM patients who are also BAP1 mutation carriers.

  6. Pediatric paraganglioma: an early manifestation of an adult disease secondary to germline mutations.

    PubMed

    Mora, Jaume; Cascón, Alberto; Robledo, Mercedes; Catala, Albert

    2006-11-01

    Paraganglioma (PGL) and phaeochromocytoma (PCC) are chemotherapy and radiation-resistant neuroendocrine tumors that arise from sympathetic tissue, and rarely occur in children. PCC may be associated with predisposing (germline) conditions like the multiple endocrine neoplasia type 2 (MEN2; OMIM 164761), von Hippel-Lindau syndrome (VHL; OMIM 193300), and rarely neurofibromatosis type 1 syndrome (NF1; OMIM 162200) and multiple endocrine neoplasia type 1 (MEN1; OMIM 131100). PGL, on the other hand, may be related to predisposing germline conditions like the familial PGL syndrome and the NF1 syndrome. In adult studies, one of the highest predisposing factors for germline mutation among patients presenting apparently sporadic PCC/PGL was their age at presentation. The aim of this study was to determine the rate of germline mutations among the rare patients presenting with sporadic PGL during childhood. In this study, we report the genetic analysis for predisposing conditions for the only three PGL cases retrospectively identified at our pediatric institution in the last 20 years. None had NF1 clinical associated lesions. Mutation screening of genes associated to VHL (VHL), MEN (RET), and familial PGL (SDH-B, -C, and -D) showed that all cases had germline deletions in the SDHB gene. We report a novel mutation, c.778 del C. Importantly, several non-symptomatic relatives were found to be carriers, thus ensuring them a clinical follow-up. According to our findings, PGL presenting during childhood represents an early manifestation of an adult disease caused by predisposing germline mutations. These results underline the importance of genetic studies in pediatric PGLs. (c) 2005 Wiley-Liss, Inc.

  7. APC2 Cullin Protein and APC11 RING Protein Comprise the Minimal Ubiquitin Ligase Module of the Anaphase-promoting Complex

    PubMed Central

    Tang, Zhanyun; Li, Bing; Bharadwaj, Rajnish; Zhu, Haizhen; Özkan, Engin; Hakala, Kevin; Deisenhofer, Johann; Yu, Hongtao

    2001-01-01

    In mitosis, the anaphase-promoting complex (APC) regulates the onset of sister-chromatid separation and exit from mitosis by mediating the ubiquitination and degradation of the securin protein and mitotic cyclins. With the use of a baculoviral expression system, we have reconstituted the ubiquitin ligase activity of human APC. In combination with Ubc4 or UbcH10, a heterodimeric complex of APC2 and APC11 is sufficient to catalyze the ubiquitination of human securin and cyclin B1. However, the minimal APC2/11 ubiquitin ligase module does not possess substrate specificity, because it also ubiquitinates the destruction box deletion mutants of securin and cyclin B1. Both APC11 and UbcH10 bind to the C-terminal cullin homology domain of APC2, whereas Ubc4 interacts with APC11 directly. Zn2+-binding and mutagenesis experiments indicate that APC11 binds Zn2+ at a 1:3 M ratio. Unlike the two Zn2+ ions of the canonical RING-finger motif, the third Zn2+ ion of APC11 is not essential for its ligase activity. Surprisingly, with Ubc4 as the E2 enzyme, Zn2+ ions alone are sufficient to catalyze the ubiquitination of cyclin B1. Therefore, the Zn2+ ions of the RING finger family of ubiquitin ligases may be directly involved in catalysis. PMID:11739784

  8. Timing of APC/C substrate degradation is determined by fzy/fzr specificity of destruction boxes

    PubMed Central

    Zur, Amit; Brandeis, Michael

    2002-01-01

    The anaphase promoting complex/cyclosome (APC/C), activated by fzy and fzr, degrades cell cycle proteins that carry RXXL or KEN destruction boxes (d-boxes). APC/C substrates regulate sequential events and must be degraded in the correct order during mitosis and G1. We studied how d-boxes determine APC/Cfzy/APC/Cfzr specificity and degradation timing. Cyclin B1 has an RXXL box and is degraded by both APC/Cfzy and APC/Cfzr; fzy has a KEN box and is degraded by APC/Cfzr only. We characterized the degradation of substrates with swapped d-boxes. Cyclin B1 with KEN was degraded by APC/Cfzr only. Fzy with RXXL could be degraded by APC/Cfzy and APC/Cfzr. Interestingly, APC/Cfzy- but not APC/Cfzr-specific degradation is highly dependent on the location of RXXL. We studied degradation of tagged substrates in real time and observed that APC/Cfzr is activated in early G1. These observations demonstrate how d-box specificities of APC/Cfzy and APC/Cfzr, and the successive activation of APC/C by fzy and fzr, establish the temporal degradation pattern. Our observations can explain further why some endogenous RXXL substrates are degraded by APC/Cfzy, while others are restricted to APC/Cfzr. PMID:12198152

  9. ELLI-1, a novel germline protein, modulates RNAi activity and P-granule accumulation in Caenorhabditis elegans.

    PubMed

    Andralojc, Karolina M; Campbell, Anne C; Kelly, Ashley L; Terrey, Markus; Tanner, Paige C; Gans, Ian M; Senter-Zapata, Michael J; Khokhar, Eraj S; Updike, Dustin L

    2017-02-01

    Germ cells contain non-membrane bound cytoplasmic organelles that help maintain germline integrity. In C. elegans they are called P granules; without them, the germline undergoes partial masculinization and aberrant differentiation. One key P-granule component is the Argonaute CSR-1, a small-RNA binding protein that antagonizes accumulation of sperm-specific transcripts in developing oocytes and fine-tunes expression of proteins critical to early embryogenesis. Loss of CSR-1 complex components results in a very specific, enlarged P-granule phenotype. In a forward screen to identify mutants with abnormal P granules, ten alleles were recovered with a csr-1 P-granule phenotype, eight of which contain mutations in known components of the CSR-1 complex (csr-1, ego-1, ekl-1, and drh-3). The remaining two alleles are in a novel gene now called elli-1 (enlarged germline granules). ELLI-1 is first expressed in primordial germ cells during mid-embryogenesis, and continues to be expressed in the adult germline. While ELLI-1 forms cytoplasmic aggregates, they occasionally dock, but do not co-localize with P granules. Instead, the majority of ELLI-1 aggregates accumulate in the shared germline cytoplasm. In elli-1 mutants, several genes that promote RNAi and P-granule accumulation are upregulated, and embryonic lethality, sterility, and RNAi resistance in a hypomorphic drh-3 allele is enhanced, suggesting that ELLI-1 functions with CSR-1 to modulate RNAi activity, P-granule accumulation, and post-transcriptional expression in the germline.

  10. Vreteno, a gonad-specific protein, is essential for germline development and primary piRNA biogenesis in Drosophila

    PubMed Central

    Zamparini, Andrea L.; Davis, Marie Y.; Malone, Colin D.; Vieira, Eric; Zavadil, Jiri; Sachidanandam, Ravi; Hannon, Gregory J.; Lehmann, Ruth

    2011-01-01

    In Drosophila, Piwi proteins associate with Piwi-interacting RNAs (piRNAs) and protect the germline genome by silencing mobile genetic elements. This defense system acts in germline and gonadal somatic tissue to preserve germline development. Genetic control for these silencing pathways varies greatly between tissues of the gonad. Here, we identified Vreteno (Vret), a novel gonad-specific protein essential for germline development. Vret is required for piRNA-based transposon regulation in both germline and somatic gonadal tissues. We show that Vret, which contains Tudor domains, associates physically with Piwi and Aubergine (Aub), stabilizing these proteins via a gonad-specific mechanism that is absent in other fly tissues. In the absence of vret, Piwi-bound piRNAs are lost without changes in piRNA precursor transcript production, supporting a role for Vret in primary piRNA biogenesis. In the germline, piRNAs can engage in an Aub- and Argonaute 3 (AGO3)-dependent amplification in the absence of Vret, suggesting that Vret function can distinguish between primary piRNAs loaded into Piwi-Aub complexes and piRNAs engaged in the amplification cycle. We propose that Vret plays an essential role in transposon regulation at an early stage of primary piRNA processing. PMID:21831924

  11. Tumour morphology predicts PALB2 germline mutation status

    PubMed Central

    Teo, Z L; Provenzano, E; Dite, G S; Park, D J; Apicella, C; Sawyer, S D; James, P A; Mitchell, G; Trainer, A H; Lindeman, G J; Shackleton, K; Cicciarelli, L; Buys, S S; Andrulis, I L; Mulligan, A M; Glendon, G; John, E M; Terry, M B; Daly, M; Odefrey, F A; Nguyen-Dumont, T; Giles, G G; Dowty, J G; Winship, I; Goldgar, D E; Hopper, J L; Southey, M C

    2013-01-01

    Background: Population-based studies of breast cancer have estimated that at least some PALB2 mutations are associated with high breast cancer risk. For women carrying PALB2 mutations, knowing their carrier status could be useful in directing them towards effective cancer risk management and therapeutic strategies. We sought to determine whether morphological features of breast tumours can predict PALB2 germline mutation status. Methods: Systematic pathology review was conducted on breast tumours from 28 female carriers of PALB2 mutations (non-carriers of other known high-risk mutations, recruited through various resources with varying ascertainment) and on breast tumours from a population-based sample of 828 Australian women diagnosed before the age of 60 years (which included 40 BRCA1 and 18 BRCA2 mutation carriers). Tumour morphological features of the 28 PALB2 mutation carriers were compared with those of 770 women without high-risk mutations. Results: Tumours arising in PALB2 mutation carriers were associated with minimal sclerosis (odds ratio (OR)=19.7; 95% confidence interval (CI)=6.0–64.6; P=5 × 10−7). Minimal sclerosis was also a feature that distinguished PALB2 mutation carriers from BRCA1 (P=0.05) and BRCA2 (P=0.04) mutation carriers. Conclusion: This study identified minimal sclerosis to be a predictor of germline PALB2 mutation status. Morphological review can therefore facilitate the identification of women most likely to carry mutations in PALB2. PMID:23787919

  12. Autologous Germline Mitochondrial Energy Transfer (AUGMENT) in Human Assisted Reproduction.

    PubMed

    Woods, Dori C; Tilly, Jonathan L

    2015-11-01

    Ovarian aging is characterized by a decline in both the total number and overall quality of oocytes, the latter of which has been experimentally tied to mitochondrial dysfunction. Clinical studies in the late 1990s demonstrated that transfer of cytoplasm aspirated from eggs of young female donors into eggs of infertile women at the time of intracytoplasmic sperm injection improved pregnancy success rates. However, donor mitochondria were identified in offspring, and the United States Food and Drug Administration raised questions about delivery of foreign genetic material into human eggs at the time of fertilization. Accordingly, heterologous cytoplasmic transfer, while promising, was in effect shut down as a clinical protocol. The recent discovery of adult oogonial (oocyte-generating) stem cells in mice, and subsequently in women, has since re-opened the prospects of delivering a rich source of pristine and patient-matched germline mitochondria to boost egg health and embryonic developmental potential without the need for young donor eggs to obtain cytoplasm. Herein we overview the science behind this new protocol, which has been patented and termed autologous germline mitochondrial energy transfer, and its use to date in clinical studies for improving pregnancy success in women with a prior history of assisted reproduction failure. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  13. Autologous Germline Mitochondrial Energy Transfer (AUGMENT) in Human Assisted Reproduction

    PubMed Central

    Woods, Dori C.; Tilly, Jonathan L.

    2017-01-01

    Ovarian aging is characterized by a decline in both the total number and overall quality of oocytes, the latter of which has been experimentally tied to mitochondrial dysfunction. Clinical studies in the late 1990s demonstrated that transfer of cytoplasm aspirated from eggs of young female donors into eggs of infertile women at the time of intracytoplasmic sperm injection improved pregnancy success rates. However, donor mitochondria were identified in offspring, and the United States Food and Drug Administration raised questions about delivery of foreign genetic material into human eggs at the time of fertilization. Accordingly, heterologous cytoplasmic transfer, while promising, was in effect shut down as a clinical protocol. The recent discovery of adult oogonial (oocyte-generating) stem cells in mice, and subsequently in women, has since re-opened the prospects of delivering a rich source of pristine and patient-matched germline mitochondria to boost egg health and embryonic developmental potential without the need for young donor eggs to obtain cytoplasm. Herein we overview the science behind this new protocol, which has been patented and termed autologous germline mitochondrial energy transfer, and its use to date in clinical studies for improving pregnancy success in women with a prior history of assisted reproduction failure. PMID:26574741

  14. Elevated germline mutation rate in teenage fathers.

    PubMed

    Forster, Peter; Hohoff, Carsten; Dunkelmann, Bettina; Schürenkamp, Marianne; Pfeiffer, Heidi; Neuhuber, Franz; Brinkmann, Bernd

    2015-03-22

    Men age and die, while cells in their germline are programmed to be immortal. To elucidate how germ cells maintain viable DNA despite increasing parental age, we analysed DNA from 24 097 parents and their children, from Europe, the Middle East and Africa. We chose repetitive microsatellite DNA that mutates (unlike point mutations) only as a result of cellular replication, providing us with a natural 'cell-cycle counter'. We observe, as expected, that the overall mutation rate for fathers is seven times higher than for mothers. Also as expected, mothers have a low and lifelong constant DNA mutation rate. Surprisingly, however, we discover that (i) teenage fathers already set out from a much higher mutation rate than teenage mothers (potentially equivalent to 77-196 male germline cell divisions by puberty); and (ii) ageing men maintain sperm DNA quality similar to that of teenagers, presumably by using fresh batches of stem cells known as 'A-dark spermatogonia'.

  15. Pediatric MDS: GATA screen the germline.

    PubMed

    Stieglitz, Elliot; Loh, Mignon L

    2016-03-17

    In this issue of Blood, Wlodarski and colleagues demonstrate that as many as 72% of adolescents diagnosed with myelodysplastic syndrome (MDS) and monosomy 7 harbor germline mutations in GATA2. Although pediatric MDS is a very rare diagnosis, occurring in 0.8 to 4 cases per million, Wlodarski et al screened >600 cases of primary or secondary MDS in children and adolescents who were enrolled in the European Working Group on MDS consortium over a period of 15 years. The overall frequency of germline GATA2 mutations in children with primary MDS was 7%, and 15% in those presenting with advanced disease. Notably, mutations in GATA2 were absent in patients with therapy-related MDS or acquired aplastic anemia.

  16. Dual PI3K/mTOR Inhibition in Colorectal Cancers with APC and PIK3CA Mutations.

    PubMed

    Foley, Tyler M; Payne, Susan N; Pasch, Cheri A; Yueh, Alex E; Van De Hey, Dana R; Korkos, Demetra P; Clipson, Linda; Maher, Molly E; Matkowskyj, Kristina A; Newton, Michael A; Deming, Dustin A

    2017-02-09

    Therapeutic targeting of the PI3K pathway is an active area of research in multiple cancer types, including breast and endometrial cancers. This pathway is commonly altered in cancer and plays an integral role in numerous vital cellular functions. Mutations in the PIK3CA gene, resulting in a constitutively active form of PI3K, often occur in colorectal cancer, though the population of patients who would benefit from targeting this pathway has yet to be identified. In human colorectal cancers, PIK3CA mutations most commonly occur concomitantly with loss of adenomatous polyposis coli (APC). Here, treatment strategies are investigated that target the PI3K pathway in colon cancers with mutations in APC and PIK3CA Colorectal cancer spheroids with Apc and Pik3ca mutations were generated and characterized confirming that these cultures represent the tumors from which they were derived. Pan and alpha isomer-specific PI3K inhibitors did not induce a significant treatment response, whereas the dual PI3K/mTOR inhibitors BEZ235 and LY3023414 induced a dramatic treatment response through decreased cellular proliferation and increased differentiation. The significant treatment responses were confirmed in mice with Apc and Pik3ca-mutant colon cancers as measured using endoscopy with a reduction in median lumen occlusion of 53% with BEZ235 and a 24% reduction with LY3023414 compared with an increase of 53% in controls (P < 0.001 and P = 0.03, respectively). This response was also confirmed with (18)F-FDG microPET/CT imaging.Implications: Spheroid models and transgenic mice suggest that dual PI3K/mTOR inhibition is a potential treatment strategy for APC and PIK3CA-mutant colorectal cancers. Thus, further clinical studies of dual PI3K/mTOR inhibitors are warranted in colorectal cancers with these mutations. Mol Cancer Res; 15(3); 1-11. ©2016 AACR.

  17. Frequent mutation of Apc gene in rat colon tumors and mucin-depleted foci, preneoplastic lesions in experimental colon carcinogenesis.

    PubMed

    Femia, Angelo Pietro; Dolara, Piero; Giannini, Augusto; Salvadori, Maddalena; Biggeri, Annibale; Caderni, Giovanna

    2007-01-15

    Mucin-depleted foci (MDF) are microscopic dysplastic lesions induced in the colon of rodents by specific colon carcinogens. Most MDF show Wnt pathway activation, whereas only a subset shows mutations in the Ctnnb1 gene, coding for beta-catenin. Because Apc is a member of the Wnt pathway and the most frequent mutated gene in human colon cancer, we tested whether MDF harbor Apc mutations. F344 rats were treated twice with 150 mg/kg of 1,2-dimethylhydrazine. After 15 or 28 weeks, MDF, aberrant crypt foci (ACF), and tumors were collected. We screened a segment of the Apc gene comprising the region homologous to the mutation cluster region (MCR) of human APC, which frequently shows mutations in experimental colon tumors. Mutations were identified by PCR amplification and sequencing in 6:24 MDF (25%), 7:23 tumors (30%), 0:24 ACF (0%). Most of the mutations (92%) in MDF and tumors were localized in a region upstream from the MCR. All mutations were single-base substitutions and mainly formed by G:C-->A:T and C:G-->T:A transitions. The pattern of nucleotide changes was similar in MDF and tumors, and, interestingly, the same mutation in codon 1047 was found in two MDF and in three tumors. Four out of the six mutations found in MDF were nonsense mutations, and two were missense. All mutations in tumors determined a protein truncation. These results show that Apc mutations are present in MDF with a frequency similar to that of tumors, strengthening the evidence that they are precancerous lesions in colon carcinogenesis.

  18. Germ-line mutation analysis in patients with multiple endocrine neoplasia type 1 and related disorders.

    PubMed Central

    Giraud, S; Zhang, C X; Serova-Sinilnikova, O; Wautot, V; Salandre, J; Buisson, N; Waterlot, C; Bauters, C; Porchet, N; Aubert, J P; Emy, P; Cadiot, G; Delemer, B; Chabre, O; Niccoli, P; Leprat, F; Duron, F; Emperauger, B; Cougard, P; Goudet, P; Sarfati, E; Riou, J P; Guichard, S; Rodier, M; Meyrier, A; Caron, P; Vantyghem, M C; Assayag, M; Peix, J L; Pugeat, M; Rohmer, V; Vallotton, M; Lenoir, G; Gaudray, P; Proye, C; Conte-Devolx, B; Chanson, P; Shugart, Y Y; Goldgar, D; Murat, A; Calender, A

    1998-01-01

    Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant syndrome predisposing to tumors of the parathyroid, endocrine pancreas, anterior pituitary, adrenal glands, and diffuse neuroendocrine tissues. The MEN1 gene has been assigned, by linkage analysis and loss of heterozygosity, to chromosome 11q13 and recently has been identified by positional cloning. In this study, a total of 84 families and/or isolated patients with either MEN1 or MEN1-related inherited endocrine tumors were screened for MEN1 germ-line mutations, by heteroduplex and sequence analysis of the MEN1 gene-coding region and untranslated exon 1. Germ-line MEN1 alterations were identified in 47/54 (87%) MEN1 families, in 9/11 (82%) isolated MEN1 patients, and in only 6/19 (31.5%) atypical MEN1-related inherited cases. We characterized 52 distinct mutations in a total of 62 MEN1 germ-line alterations. Thirty-five of the 52 mutations were frameshifts and nonsense mutations predicted to encode for a truncated MEN1 protein. We identified eight missense mutations and five in-frame deletions over the entire coding sequence. Six mutations were observed more than once in familial MEN1. Haplotype analysis in families with identical mutations indicate that these occurrences reflected mainly independent mutational events. No MEN1 germ-line mutations were found in 7/54 (13%) MEN1 families, in 2/11 (18%) isolated MEN1 cases, in 13/19 (68. 5%) MEN1-related cases, and in a kindred with familial isolated hyperparathyroidism. Two hundred twenty gene carriers (167 affected and 53 unaffected) were identified. No evidence of genotype-phenotype correlation was found. Age-related penetrance was estimated to be >95% at age >30 years. Our results add to the diversity of MEN1 germ-line mutations and provide new tools in genetic screening of MEN1 and clinically related cases. PMID:9683585

  19. Mitochondrial DNA Polymerase POLG1 Disease Mutations and Germline Variants Promote Tumorigenic Properties.

    PubMed

    Singh, Bhupendra; Owens, Kjerstin M; Bajpai, Prachi; Desouki, Mohamed Mokhtar; Srinivasasainagendra, Vinodh; Tiwari, Hemant K; Singh, Keshav K

    2015-01-01

    Germline mutations in mitochondrial DNA polymerase gamma (POLG1) induce mitochondrial DNA (mtDNA) mutations, depletion, and decrease oxidative phosphorylation. Earlier, we identified somatic mutations in POLG1 and the contribution of these mutations in human cancer. However, a role for germline variations in POLG1 in human cancers is unknown. In this study, we examined a role for disease associated germline variants of POLG1, POLG1 gene expression, copy number variation and regulation in human cancers. We analyzed the mutations, expression and copy number variation in POLG1 in several cancer databases and validated the analyses in primary breast tumors and breast cancer cell lines. We discovered 5-aza-2'-deoxycytidine led epigenetic regulation of POLG1, mtDNA-encoded genes and increased mitochondrial respiration. We conducted comprehensive race based bioinformatics analyses of POLG1 gene in more than 33,000 European-Americans and 5,000 African-Americans. We identified a mitochondrial disease causing missense variation in polymerase domain of POLG1 protein at amino acid 1143 (E1143G) to be 25 times more prevalent in European-Americans (allele frequency 0.03777) when compared to African-American (allele frequency 0.00151) population. We identified T251I and P587L missense variations in exonuclease and linker region of POLG1 also to be more prevalent in European-Americans. Expression of these variants increased glucose consumption, decreased ATP production and increased matrigel invasion. Interestingly, conditional expression of these variants revealed that matrigel invasion properties conferred by these germline variants were reversible suggesting a role of epigenetic regulators. Indeed, we identified a set of miRNA whose expression was reversible after variant expression was turned off. Together, our studies demonstrate altered genetic and epigenetic regulation of POLG1 in human cancers and suggest a role for POLG1 germline variants in promoting tumorigenic

  20. Pituitary blastoma: a pathognomonic feature of germ-line DICER1 mutations.

    PubMed

    de Kock, Leanne; Sabbaghian, Nelly; Plourde, François; Srivastava, Archana; Weber, Evan; Bouron-Dal Soglio, Dorothée; Hamel, Nancy; Choi, Joon Hyuk; Park, Sung-Hye; Deal, Cheri L; Kelsey, Megan M; Dishop, Megan K; Esbenshade, Adam; Kuttesch, John F; Jacques, Thomas S; Perry, Arie; Leichter, Heinz; Maeder, Philippe; Brundler, Marie-Anne; Warner, Justin; Neal, James; Zacharin, Margaret; Korbonits, Márta; Cole, Trevor; Traunecker, Heidi; McLean, Thomas W; Rotondo, Fabio; Lepage, Pierre; Albrecht, Steffen; Horvath, Eva; Kovacs, Kalman; Priest, John R; Foulkes, William D

    2014-07-01

    Individuals harboring germ-line DICER1 mutations are predisposed to a rare cancer syndrome, the DICER1 Syndrome or pleuropulmonary blastoma-familial tumor and dysplasia syndrome [online Mendelian inheritance in man (OMIM) #601200]. In addition, specific somatic mutations in the DICER1 RNase III catalytic domain have been identified in several DICER1-associated tumor types. Pituitary blastoma (PitB) was identified as a distinct entity in 2008, and is a very rare, potentially lethal early childhood tumor of the pituitary gland. Since the discovery by our team of an inherited mutation in DICER1 in a child with PitB in 2011, we have identified 12 additional PitB cases. We aimed to determine the contribution of germ-line and somatic DICER1 mutations to PitB. We hypothesized that PitB is a pathognomonic feature of a germ-line DICER1 mutation and that each PitB will harbor a second somatic mutation in DICER1. Lymphocyte or saliva DNA samples ascertained from ten infants with PitB were screened and nine were found to harbor a heterozygous germ-line DICER1 mutation. We identified additional DICER1 mutations in nine of ten tested PitB tumor samples, eight of which were confirmed to be somatic in origin. Seven of these mutations occurred within the RNase IIIb catalytic domain, a domain essential to the generation of 5p miRNAs from the 5' arm of miRNA-precursors. Germ-line DICER1 mutations are a major contributor to PitB. Second somatic DICER1 "hits" occurring within the RNase IIIb domain also appear to be critical in PitB pathogenesis.

  1. Exome sequencing identifies potential novel candidate genes in patients with unexplained colorectal adenomatous polyposis.

    PubMed

    Spier, Isabel; Kerick, Martin; Drichel, Dmitriy; Horpaopan, Sukanya; Altmüller, Janine; Laner, Andreas; Holzapfel, Stefanie; Peters, Sophia; Adam, Ronja; Zhao, Bixiao; Becker, Tim; Lifton, Richard P; Holinski-Feder, Elke; Perner, Sven; Thiele, Holger; Nöthen, Markus M; Hoffmann, Per; Timmermann, Bernd; Schweiger, Michal R; Aretz, Stefan

    2016-04-01

    In up to 30% of patients with colorectal adenomatous polyposis, no germline mutation in the known genes APC, causing familial adenomatous polyposis, MUTYH, causing MUTYH-associated polyposis, and POLE or POLD1, causing Polymerase-Proofreading-associated polyposis can be identified, although a hereditary etiology is likely. To uncover new causative genes, exome sequencing was performed using DNA from leukocytes and a total of 12 colorectal adenomas from seven unrelated patients with unexplained sporadic adenomatous polyposis. For data analysis and variant filtering, an established bioinformatics pipeline including in-house tools was applied. Variants were filtered for rare truncating point mutations and copy-number variants assuming a dominant, recessive, or tumor suppressor model of inheritance. Subsequently, targeted sequence analysis of the most promising candidate genes was performed in a validation cohort of 191 unrelated patients. All relevant variants were validated by Sanger sequencing. The analysis of exome sequencing data resulted in the identification of rare loss-of-function germline mutations in three promising candidate genes (DSC2, PIEZO1, ZSWIM7). In the validation cohort, further variants predicted to be pathogenic were identified in DSC2 and PIEZO1. According to the somatic mutation spectra, the adenomas in this patient cohort follow the classical pathways of colorectal tumorigenesis. The present study identified three candidate genes which might represent rare causes for a predisposition to colorectal adenoma formation. Especially PIEZO1 (FAM38A) and ZSWIM7 (SWS1) warrant further exploration. To evaluate the clinical relevance of these genes, investigation of larger patient cohorts and functional studies are required.

  2. [The return of germline gene therapy].

    PubMed

    Jordan, Bertrand

    2015-01-01

    The recent development of a powerful and flexible genome editing technique (the CRISP-cas9 method) accelerates tremendously the production of animal models and will significantly enhance the perspectives of (somatic) gene therapy. However, it also raises a real possibility of germline modifications in humans, with therapeutic aims or for "improvement": this raises thorny ethical questions that are no longer theoretical (as in the 1990s) but will have to be faced in the very near future.

  3. The E3 ligase APC/C(Cdh1) promotes ubiquitylation-mediated proteolysis of PAX3 to suppress melanocyte proliferation and melanoma growth.

    PubMed

    Cao, Juxiang; Dai, Xiangpeng; Wan, Lixin; Wang, Hongshen; Zhang, Jinfang; Goff, Philip S; Sviderskaya, Elena V; Xuan, Zhenyu; Xu, Zhixiang; Xu, Xiaowei; Hinds, Philip; Flaherty, Keith T; Faller, Douglas V; Goding, Colin R; Wang, Yongjun; Wei, Wenyi; Cui, Rutao

    2015-09-01

    The anaphase-promoting complex or cyclosome with the subunit Cdh1 (APC/C(Cdh1)) is an E3 ubiquitin ligase involved in the control of the cell cycle. Here, we identified sporadic mutations occurring in the genes encoding APC components, including Cdh1, in human melanoma samples and found that loss of APC/C(Cdh1) may promote melanoma development and progression, but not by affecting cell cycle regulatory targets of APC/C. Most of the mutations we found in CDH1 were those associated with ultraviolet light (UV)-induced melanomagenesis. Compared with normal human skin tissue and human or mouse melanocytes, the abundance of Cdh1 was decreased and that of the transcription factor PAX3 was increased in human melanoma tissue and human or mouse melanoma cell lines, respectively; Cdh1 abundance was further decreased with advanced stages of human melanoma. PAX3 was a substrate of APC/C(Cdh1) in melanocytes, and APC/C(Cdh1)-mediated ubiquitylation marked PAX3 for proteolytic degradation in a manner dependent on the D-box motif in PAX3. Either mutating the D-box in PAX3 or knocking down Cdh1 prevented the ubiquitylation and degradation of PAX3 and increased proliferation and melanin production in melanocytes. Knocking down Cdh1 in melanoma cells in culture or before implantation in mice promoted doxorubicin resistance, whereas reexpressing wild-type Cdh1, but not E3 ligase-deficient Cdh1 or a mutant that could not interact with PAX3, restored doxorubicin sensitivity in melanoma cells both in culture and in xenografts. Thus, our findings suggest a tumor suppressor role for APC/C(Cdh1) in melanocytes and that targeting PAX3 may be a strategy for treating melanoma.

  4. Assessing the effects of a sequestered germline on interdomain lateral gene transfer in Metazoa.

    PubMed

    Jensen, Lindy; Grant, Jessica R; Laughinghouse, Haywood Dail; Katz, Laura A

    2016-06-01

    A sequestered germline in Metazoa has been argued to be an obstacle to lateral gene transfer (LGT), though few studies have specifically assessed this claim. Here, we test the hypothesis that the origin of a sequestered germline reduced LGT events in Bilateria (i.e., triploblast lineages) as compared to early-diverging Metazoa (i.e., Ctenophora, Cnidaria, Porifera, and Placozoa). We analyze single-gene phylogenies generated with over 900 species sampled from among Bacteria, Archaea, and Eukaryota to identify well-supported interdomain LGTs. We focus on ancient interdomain LGT (i.e., those between prokaryotes and multiple lineages of Metazoa) as systematic errors in single-gene tree reconstruction create uncertainties for interpreting eukaryote-to-eukaryote transfer. The breadth of the sampled Metazoa enables us to estimate the timing of LGTs, and to examine the pattern before versus after the evolution of a sequestered germline. We identified 58 LGTs found only in Metazoa and prokaryotes (i.e., bacteria and/or archaea), and seven genes transferred from prokaryotes into Metazoa plus one other eukaryotic clade. Our analyses indicate that more interdomain transfers occurred before the development of a sequestered germline, consistent with the hypothesis that this feature is an obstacle to LGT. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  5. Fission Yeast Apc15 Stabilizes MCC-Cdc20-APC/C Complexes, Ensuring Efficient Cdc20 Ubiquitination and Checkpoint Arrest.

    PubMed

    May, Karen M; Paldi, Flora; Hardwick, Kevin G

    2017-03-28

    During mitosis, cells must segregate the replicated copies of their genome to their daughter cells with extremely high fidelity. Segregation errors lead to an abnormal chromosome number (aneuploidy), which typically results in disease or cell death [1]. Chromosome segregation and anaphase onset are initiated through the action of the multi-subunit E3 ubiquitin ligase known as the anaphase-promoting complex or cyclosome (APC/C [2]). The APC/C is inhibited by the spindle checkpoint in the presence of kinetochore attachment defects [3, 4]. Here we demonstrate that two non-essential APC/C subunits (Apc14 and Apc15) regulate association of spindle checkpoint proteins, in the form of the mitotic checkpoint complex (MCC), with the APC/C. apc14Δ mutants display increased MCC association with the APC/C and are unable to silence the checkpoint efficiently. Conversely, apc15Δ mutants display reduced association between the MCC and APC/C, are defective in poly-ubiquitination of Cdc20, and are checkpoint defective. In vitro reconstitution studies have shown that human MCC-APC/C can contain two molecules of Cdc20 [5-7]. Using a yeast strain expressing two Cdc20 genes with different epitope tags, we show by co-immunoprecipitation that this is true in vivo. MCC binding to the second molecule of Cdc20 is mediated via the C-terminal KEN box in Mad3. Somewhat surprisingly, complexes containing both molecules of Cdc20 accumulate in apc15Δ cells, and the implications of this observation are discussed.

  6. Single-molecule spectroscopy and femtosecond transient absorption studies on the excitation energy transfer process in ApcE(1-240) dimers.

    PubMed

    Long, Saran; Zhou, Meng; Tang, Kun; Zeng, Xiao-Li; Niu, Yingli; Guo, Qianjin; Zhao, Kai-Hong; Xia, Andong

    2015-05-28

    ApcE(1-240) dimers with one intrinsic phycocyanobilin (PCB) chromophore in each monomer that is truncated from the core-membrane linker (ApcE) of phycobilisomes (PBS) in Nostoc sp. PCC 7120 show a sharp and significantly red-shifted absorption. Two explanations either conformation-dependent Förster resonance energy transfer (FRET) or the strong exciton coupling limit have been proposed for red-shifted absorption. This is a classic example of the special pair in the photosynthetic light harvesting proteins, but the mechanism of this interaction is still a matter of intense debate. We report the studies using single-molecule and transient absorption spectra on the interaction in the special pair of ApcE dimers. Our results demonstrate the presence of conformation-dependent FRET between the two PCB chromophores in ApcE dimers. The broad distributions of fluorescence intensities, lifetimes and polarization difference from single-molecule measurements reveal the heterogeneity of local protein-pigment environments in ApcE dimers, where the same molecular structures but different protein environments are the main reason for the two PCB chromophores with different spectral properties. The excitation energy transfer rate between the donor and the acceptor about (110 ps)(-1) is determined from transient absorption measurements. The red-shifted absorption in ApcE dimers could result from more extending conformation, which shows another type of absorption redshift that does not depend on strong exciton coupling. The results here stress the importance of conformation-controlled spectral properties of the chemically identical chromophores, which could be a general feature to control energy/electron transfer, widely existing in the light harvesting complexes.

  7. Germline genome-editing research and its socioethical implications.

    PubMed

    Ishii, Tetsuya

    2015-08-01

    Genetically modifying eggs, sperm, and zygotes ('germline' modification) can impact on the entire body of the resulting individual and on subsequent generations. With the advent of genome-editing technology, human germline gene modification is no longer theoretical. Owing to increasing concerns about human germline gene modification, a voluntary moratorium on human genome-editing research and/or the clinical application of human germline genome editing has recently been called for. However, whether such research should be suspended or encouraged warrants careful consideration. The present article reviews recent research on mammalian germline genome editing, discusses the importance of public dialogue on the socioethical implications of human germline genome-editing research, and considers the relevant guidelines and legislation in different countries.

  8. Estimation of the potential antitumor activity of microencapsulated Lactobacillus acidophilus yogurt formulation in the attenuation of tumorigenesis in Apc(Min/+) mice.

    PubMed

    Urbanska, Aleksandra Malgorzata; Bhathena, Jasmine; Martoni, Christopher; Prakash, Satya

    2009-02-01

    There is a strong correlation between orally administered probiotics and suppression of the low-grade inflammation that can lead to restoration of normal local immune functions. We studied the potential immunomodulatory and antitumorigenic properties of microencapsulated probiotic bacterial cells in a yogurt formulation in Min mice carrying a germline APC mutation. Daily oral administration of microencapsulated Lactobacillus acidophilus bacterial cells in the yogurt formulation mice resulted in significant suppression of colon tumor incidence, tumor multiplicity, and reduced tumor size. Results show that oral administration of microencapsulated L. acidophilus contributed to the stabilization of animal body weight and decreased the release of bile acids. Histopathological analyses revealed fewer adenomas in treated versus untreated animals. Furthermore, treated animals exhibited fewer gastrointestinal intra-epithelial neoplasias with a lower grade of dysplasia in detected tumors. Results suggest that oral administration of microencapsulated probiotic L. acidophilus exerts anti-tumorous activity, which consequently leads to reduced tumor outcome.

  9. Selection for Mitochondrial Quality Drives Evolution of the Germline

    PubMed Central

    Radzvilavicius, Arunas L.; Hadjivasiliou, Zena; Pomiankowski, Andrew; Lane, Nick

    2016-01-01

    The origin of the germline–soma distinction is a fundamental unsolved question. Plants and basal metazoans do not have a germline but generate gametes from pluripotent stem cells in somatic tissues (somatic gametogenesis). In contrast, most bilaterians sequester a dedicated germline early in development. We develop an evolutionary model which shows that selection for mitochondrial quality drives germline evolution. In organisms with low mitochondrial replication error rates, segregation of mutations over multiple cell divisions generates variation, allowing selection to optimize gamete quality through somatic gametogenesis. Higher mutation rates promote early germline sequestration. We also consider how oogamy (a large female gamete packed with mitochondria) alters selection on the germline. Oogamy is beneficial as it reduces mitochondrial segregation in early development, improving adult fitness by restricting variation between tissues. But it also limits variation between early-sequestered oocytes, undermining gamete quality. Oocyte variation is restored through proliferation of germline cells, producing more germ cells than strictly needed, explaining the random culling (atresia) of precursor cells in bilaterians. Unlike other models of germline evolution, selection for mitochondrial quality can explain the stability of somatic gametogenesis in plants and basal metazoans, the evolution of oogamy in all plants and animals with tissue differentiation, and the mutational forces driving early germline sequestration in active bilaterians. The origins of predation in motile bilaterians in the Cambrian explosion is likely to have increased rates of tissue turnover and mitochondrial replication errors, in turn driving germline evolution and the emergence of complex developmental processes. PMID:27997535

  10. Spontaneous Intestinal Tumorigenesis in Apc (/Min+) Mice Requires Altered T Cell Development with IL-17A.

    PubMed

    Chae, Wook-Jin; Bothwell, Alfred L M

    2015-01-01

    The control of inflammatory diseases requires functional regulatory T cells (Tregs) with significant Gata-3 expression. Here we address the inhibitory role of Tregs on intestinal tumorigenesis in the Apc (/Min+) mouse model that resembles human familial adenomatous polyposis (FAP). Apc (/Min+) mice had a markedly increased frequency of Foxp3+ Tregs and yet decreased Gata-3 expression in the lamina propria. To address the role of heterozygous Apc gene mutation in Tregs, we generated Foxp3-Cre, Apc (flox/+) mice. Tregs from these mice effectively inhibited tumorigenesis comparable to wild type Tregs after adoptive transfer into Apc (/Min+) mice, demonstrating that the heterozygous Apc gene mutation in Tregs does not induce the loss of control over tumor microenvironment. Adoptive transfer of in vitro generated Apc (/Min+) iTregs (inducible Tregs) failed to inhibit intestinal tumorigenesis, suggesting that naïve CD4 T cells generated from Apc (/Min+) mice thymus were impaired. We also showed that adoptively transferred IL-17A-deficient Apc (/Min+) Tregs inhibited tumor growth, suggesting that IL-17A was critical to impair the tumor regression function of Apc (/Min+) Tregs. Taken together, our results suggest that both T cell development in a functional thymus and IL-17A control the ability of Treg to inhibit intestinal tumorigenesis in Apc (/Min+) mice.

  11. The anticoagulant activated protein C (aPC) promotes metaplasticity in the hippocampus through an EPCR-PAR1-S1P1 receptors dependent mechanism.

    PubMed

    Maggio, Nicola; Itsekson, Zeev; Ikenberg, Benno; Strehl, Andreas; Vlachos, Andreas; Blatt, Ilan; Tanne, David; Chapman, Joab

    2014-08-01

    Thrombin and other clotting factors regulate long-term potentiation (LTP) in the hippocampus through the activation of the protease activated receptor 1 (PAR1) and consequent potentiation of N-methyl-d-aspartate receptor (NMDAR) functions. We have recently shown that the activation of PAR1 either by thrombin or the anticoagulant factor activated protein C (aPC) has differential effects on LTP. While thrombin activation of PAR1 induces an NMDAR-mediated slow onset LTP, which saturates the ability to induce further LTP in the exposed network, aPC stimulation of PAR1 enhances tetanus induced LTP through a voltage-gated calcium channels mediated mechanism. In this study, we addressed the mechanisms by which aPC enhances LTP in hippocampal slices. Using extracellular recordings, we show that a short tetanic stimulation, which does not induce LTP, is able to enhance plasticity in the presence of aPC through a mechanism that requires the activation of sphingosine-1 phosphate receptor 1 and intracellular Ca(2+) stores. These data identify aPC as a "metaplastic molecule", capable of shifting the threshold of LTP towards further potentiation. Our findings propose novel strategies to enhance plasticity in neurological diseases associated with the breakdown of the blood brain barrier and alterations in synaptic plasticity. © 2014 Wiley Periodicals, Inc.

  12. A Cdh1-APC/FMRP Ubiquitin Signaling Link Drives mGluR-Dependent Synaptic Plasticity in the Mammalian Brain.

    PubMed

    Huang, Ju; Ikeuchi, Yoshiho; Malumbres, Marcos; Bonni, Azad

    2015-05-06

    Deregulation of synaptic plasticity may contribute to the pathogenesis of developmental cognitive disorders. In particular, exaggerated mGluR-dependent LTD is featured in fragile X syndrome, but the mechanisms that regulate mGluR-LTD remain incompletely understood. We report that conditional knockout of Cdh1, the key regulatory subunit of the ubiquitin ligase Cdh1-anaphase-promoting complex (Cdh1-APC), profoundly impairs mGluR-LTD in the hippocampus. Mechanistically, we find that Cdh1-APC operates in the cytoplasm to drive mGluR-LTD. We also identify the fragile X syndrome protein FMRP as a substrate of Cdh1-APC. Endogenous Cdh1-APC forms a complex with endogenous FMRP, and knockout of Cdh1 impairs mGluR-induced ubiquitination and degradation of FMRP in the hippocampus. Knockout of FMRP suppresses, and expression of an FMRP mutant protein that fails to interact with Cdh1 phenocopies, the Cdh1 knockout phenotype of impaired mGluR-LTD. These findings define Cdh1-APC and FMRP as components of a novel ubiquitin signaling pathway that regulates mGluR-LTD in the brain.

  13. Female mice lack adult germ-line stem cells but sustain oogenesis using stable primordial follicles.

    PubMed

    Lei, Lei; Spradling, Allan C

    2013-05-21

    Whether or not mammalian females generate new oocytes during adulthood from germ-line stem cells to sustain the ovarian follicle pool has recently generated controversy. We used a sensitive lineage-labeling system to determine whether stem cells are needed in female adult mice to compensate for follicular losses and to directly identify active germ-line stem cells. Primordial follicles generated during fetal life are highly stable, with a half-life during adulthood of 10 mo, and thus are sufficient to sustain adult oogenesis without a source of renewal. Moreover, in normal mice or following germ-cell depletion with Busulfan, only stable, single oocytes are lineage-labeled, rather than cell clusters indicative of new oocyte formation. Even one germ-line stem cell division per 2 wk would have been detected by our method, based on the kinetics of fetal follicle formation. Thus, adult female mice neither require nor contain active germ-line stem cells or produce new oocytes in vivo.

  14. Generation of transgenic quail through germ cell-mediated germline transmission.

    PubMed

    Shin, Sang Su; Kim, Tae Min; Kim, Sun Young; Kim, Tae Wan; Seo, Hee Won; Lee, Seul Ki; Kwon, Se Chang; Lee, Gwan Sun; Kim, Heebal; Lim, Jeong Mook; Han, Jae Yong

    2008-07-01

    Here, we describe the production of transgenic quail via a germline transmission system using postmigratory gonadal primordial germ cells (gPGCs). gPGCs retrieved from the embryonic gonads of 5-day-old birds were transduced with a lentiviral vector and subsequently transferred into recipient embryos. Testcross and genetic analyses revealed that among three germline chimeric G0 quail, one male produced transgenic offspring; of 310 hatchlings from the transgenic germline chimera, 24 were identified as donor-derived offspring, and 6 were transgenic (6/310, 1.9%). Conventional transgenesis using stage X blastodermal embryos was also conducted, but the efficiency of transgenesis was similar between the two systems (<1.6 vs. 1.9% for the conventional and gPGC-mediated systems, respectively). However, substantial advantages can be gained from gPGC-mediated method in that it enables an induced germline modification, whereas direct retroviral transfer to stage X embryos causes mosaic integration. The use of gonadal PGCs for transgenesis may lead to the production of bioreactors.

  15. Evolutionarily conserved mechanisms of male germline development in flowering plants and animals.

    PubMed

    Pereira, Patrícia A; Navarro-Costa, Paulo; Martinho, Rui Gonçalo; Becker, Jörg D

    2014-04-01

    Sexual reproduction is the main reproductive strategy of the overwhelming majority of eukaryotes. This suggests that the last eukaryotic common ancestor was able to reproduce sexually. Sexual reproduction reflects the ability to perform meiosis, and ultimately generating gametes, which are cells that carry recombined half sets of the parental genome and are able to fertilize. These functions have been allocated to a highly specialized cell lineage: the germline. Given its significant evolutionary conservation, it is to be expected that the germline programme shares common molecular bases across extremely divergent eukaryotic species. In the present review, we aim to identify the unifying principles of male germline establishment and development by comparing two very disparate kingdoms: plants and animals. We argue that male meiosis defines two temporally regulated gene expression programmes: the first is required for meiotic commitment, and the second is required for the acquisition of fertilizing ability. Small RNA pathways are a further key communality, ultimately ensuring the epigenetic stability of the information conveyed by the male germline.

  16. Genomic hypomethylation in the human germline associates with selective structural mutability in the human genome.

    PubMed

    Li, Jian; Harris, R Alan; Cheung, Sau Wai; Coarfa, Cristian; Jeong, Mira; Goodell, Margaret A; White, Lisa D; Patel, Ankita; Kang, Sung-Hae; Shaw, Chad; Chinault, A Craig; Gambin, Tomasz; Gambin, Anna; Lupski, James R; Milosavljevic, Aleksandar

    2012-01-01

    The hotspots of structural polymorphisms and structural mutability in the human genome remain to be explained mechanistically. We examine associations of structural mutability with germline DNA methylation and with non-allelic homologous recombination (NAHR) mediated by low-copy repeats (LCRs). Combined evidence from four human sperm methylome maps, human genome evolution, structural polymorphisms in the human population, and previous genomic and disease studies consistently points to a strong association of germline hypomethylation and genomic instability. Specifically, methylation deserts, the ~1% fraction of the human genome with the lowest methylation in the germline, show a tenfold enrichment for structural rearrangements that occurred in the human genome since the branching of chimpanzee and are highly enriched for fast-evolving loci that regulate tissue-specific gene expression. Analysis of copy number variants (CNVs) from 400 human samples identified using a custom-designed array comparative genomic hybridization (aCGH) chip, combined with publicly available structural variation data, indicates that association of structural mutability with germline hypomethylation is comparable in magnitude to the association of structural mutability with LCR-mediated NAHR. Moreover, rare CNVs occurring in the genomes of individuals diagnosed with schizophrenia, bipolar disorder, and developmental delay and de novo CNVs occurring in those diagnosed with autism are significantly more concentrated within hypomethylated regions. These findings suggest a new connection between the epigenome, selective mutability, evolution, and human disease.

  17. Germline stem cells are critical for sexual fate decision of germ cells

    PubMed Central

    2016-01-01

    Egg or sperm? The mechanism of sexual fate decision in germ cells has been a long‐standing issue in biology. A recent analysis identified foxl3 as a gene that determines the sexual fate decision of germ cells in the teleost fish, medaka. foxl3/Foxl3 acts in female germline stem cells to repress commitment into male fate (spermatogenesis), indicating that the presence of mitotic germ cells in the female is critical for continuous sexual fate decision of germ cells in medaka gonads. Interestingly, foxl3 is found in most vertebrate genomes except for mammals. This provides the interesting possibility that the sexual fate of germ cells in mammals is determined in a different way compared to foxl3‐possessing vertebrates. Considering the fact that germline stem cells are the cells where foxl3 begins to express and sexual fate decision initiates and mammalian ovary does not have typical germline stem cells, the mechanism in mammals may have been co‐evolved with germline stem cell loss in mammalian ovary. PMID:27699806

  18. Paternal lifestyle as a potential source of germline mutations transmitted to offspring.

    PubMed

    Linschooten, Joost O; Verhofstad, Nicole; Gutzkow, Kristine; Olsen, Ann-Karin; Yauk, Carole; Oligschläger, Yvonne; Brunborg, Gunnar; van Schooten, Frederik J; Godschalk, Roger W L

    2013-07-01

    Paternal exposure to high levels of radioactivity causes heritable germline minisatellite mutations. However, the effect of more general paternal exposures, such as cigarette smoking, on germline mutations remains unexplored. We analyzed two of the most commonly used minisatellite loci (CEB1 and B6.7) to identify germline mutations in blood samples of complete mother-father-child triads from the Norwegian Mother and Child Cohort Study (MoBa). The presence of mutations was subsequently related to general lifestyle factors, including paternal smoking before the partner became pregnant. Paternally derived mutations at the B6.7 locus (mutation frequency 0.07) were not affected by lifestyle. In contrast, high gross yearly income as a general measure of a healthy lifestyle coincided with low-mutation frequencies at the CEB1 locus (P=0.047). Income was inversely related to smoking behavior, and paternally derived CEB1 mutations were dose dependently increased when the father smoked in the 6 mo before pregnancy, 0.21 vs. 0.05 in smoking and nonsmoking fathers, respectively (P=0.061). These results suggest that paternal lifestyle can affect the chance of heritable mutations in unstable repetitive DNA sequences. To our knowledge, this is the first study reporting an effect of lifestyle on germline minisatellite mutation frequencies in a human population with moderate paternal exposures.

  19. Genomic Hypomethylation in the Human Germline Associates with Selective Structural Mutability in the Human Genome

    PubMed Central

    Li, Jian; Harris, R. Alan; Cheung, Sau Wai; Coarfa, Cristian; Jeong, Mira; Goodell, Margaret A.; White, Lisa D.; Patel, Ankita; Kang, Sung-Hae; Shaw, Chad; Chinault, A. Craig; Gambin, Tomasz; Gambin, Anna; Lupski, James R.; Milosavljevic, Aleksandar

    2012-01-01

    The hotspots of structural polymorphisms and structural mutability in the human genome remain to be explained mechanistically. We examine associations of structural mutability with germline DNA methylation and with non-allelic homologous recombination (NAHR) mediated by low-copy repeats (LCRs). Combined evidence from four human sperm methylome maps, human genome evolution, structural polymorphisms in the human population, and previous genomic and disease studies consistently points to a strong association of germline hypomethylation and genomic instability. Specifically, methylation deserts, the ∼1% fraction of the human genome with the lowest methylation in the germline, show a tenfold enrichment for structural rearrangements that occurred in the human genome since the branching of chimpanzee and are highly enriched for fast-evolving loci that regulate tissue-specific gene expression. Analysis of copy number variants (CNVs) from 400 human samples identified using a custom-designed array comparative genomic hybridization (aCGH) chip, combined with publicly available structural variation data, indicates that association of structural mutability with germline hypomethylation is comparable in magnitude to the association of structural mutability with LCR–mediated NAHR. Moreover, rare CNVs occurring in the genomes of individuals diagnosed with schizophrenia, bipolar disorder, and developmental delay and de novo CNVs occurring in those diagnosed with autism are significantly more concentrated within hypomethylated regions. These findings suggest a new connection between the epigenome, selective mutability, evolution, and human disease. PMID:22615578

  20. Screening for germline mismatch repair mutations following diagnosis of sebaceous neoplasm.

    PubMed

    Everett, Jessica N; Raymond, Victoria M; Dandapani, Monica; Marvin, Monica; Kohlmann, Wendy; Chittenden, Anu; Koeppe, Erika; Gustafson, Shanna L; Else, Tobias; Fullen, Douglas R; Johnson, Timothy M; Syngal, Sapna; Gruber, Stephen B; Stoffel, Elena M

    2014-12-01

    IMPORTANCE Sebaceous neoplasms (SNs) define the Muir-Torre syndrome variant of Lynch syndrome (LS), which is associated with increased risk for colon and other cancers necessitating earlier and more frequent screening to reduce morbidity and mortality.Immunohistochemical (IHC) staining for mismatch repair (MMR) proteins in SNs can be used to screen for LS, but data on subsequent germline genetic testing to confirm LS diagnosis are limited.OBJECTIVE To characterize the utility of IHC screening of SNs in identification of germline MMR mutations confirming LS.DESIGN, SETTING, AND PARTICIPANTS Retrospective study at 2 academic cancer centers of 86 adult patients referred for clinical genetics evaluation after diagnosis of SN.MAIN OUTCOMES AND MEASURES Results of tumor IHC testing and germline genetic testing were reviewed to determine positive predictive value and sensitivity of IHC testing in diagnosis of LS. Clinical variables, including age at diagnosis of SN, clinical diagnostic criteria for LS and Muir-Torre syndrome, and family history characteristics were compared between mutation carriers and noncarriers.RESULTS Of 86 patients with SNs, 25 (29%) had germline MMR mutations confirming LS.Among 77 patients with IHC testing on SNs, 38 (49%) had loss of staining of 1 or more MMR proteins and 14 had germline MMR mutations. Immunohistochemical analysis correctly identified 13 of 16 MMR mutation carriers, corresponding to 81% sensitivity. Ten of 12 patients(83%) with more than 1 SN had MMR mutations. Fifty-two percent of MMR mutation carriers did not meet clinical diagnostic criteria for LS, and 11 of 25 (44%) did not meet the clinical definition of Muir-Torre syndrome. CONCLUSIONS AND RELEVANCE Immunohistochemical screening of SNs is effective in identifying patients with germline MMR mutations and can be used as a first-line test when LSis suspected. Abnormal IHC results, including absence of MSH2, are not diagnostic of LS and should be interpreted cautiously in

  1. Mechanism of Adenomatous Polyposis Coli (APC)-mediated Blockage of Longpatch Base Excision Repair†

    PubMed Central

    Jaiswal, Aruna S.; Balusu, Ramesh; Armas, Melissa L.; Kundu, Chanakya N.; Narayan, Satya

    2008-01-01

    Recently, we found an interaction between adenomatous polyposis coli (APC) and DNA polymerase β (pol-β) and showed that APC blocks strand-displacement synthesis of long-patch base excision repair (LP-BER) however, the mechanism is not clear. Using an in vivo LP-BER assay system, we now show that the LP-BER is higher in APC−/− cells than in APC+/+ cells. In addition to pol-β, the pull-down experiments showed that the full-length APC also interacted with flap endonuclease 1 (Fen-1). To further characterize the interaction of APC with pol-β and Fen-1, we performed a domain-mapping of APC and found that both pol-β and Fen-1 interact with a 138-amino acids peptide from the APC at the DRI-domain. Our functional assays showed that APC blocks pol-β-mediated 1-nucleotide (1-nt) as well as strand-displacement synthesis of reduced abasic, nicked-, or 1-nt gapped-DNA substrates. Our further studies demonstrated that APC blocks 5′-flap endonuclease as well as 5′-3′ exonuclease activity of Fen-1 resulting in the blockage of LP-BER. From these results we concluded that APC can have three different effects in the LP-BER pathway. First, APC can block pol-β-mediated 1-nt incorporation and strand-displacement synthesis. Second, APC can block LP-BER by blocking coordinated formation and removal of the strand-displaced flap. Third, APC can block LP-BER by blocking “Hit and Run” synthesis. These studies will have important implications of APC in DNA damage-induced carcinogenesis and chemoprevention. PMID:17176113

  2. Extrinsic intestinal denervation modulates tumor development in the small intestine of Apc(Min/+) mice.

    PubMed

    Liu, Verena; Dietrich, Alexandra; Kasparek, Michael S; Benhaqi, Petra; Schneider, Marlon R; Schemann, Michael; Seeliger, Hendrik; Kreis, Martin E

    2015-04-29

    Innervation interacts with enteric immune responses. Chronic intestinal inflammation is associated with increased risk of colorectal cancer. We aimed to study potential extrinsic neuronal modulation of intestinal tumor development in a mouse model. Experiments were performed with male Apc(Min/+) or wild type mice (4 weeks old, body weight approximately 20 g). Subgroups with subdiaphragmatic vagotomy (apcV/wtV), sympathetic denervation of the small intestine (apcS/wtS) or sham operated controls (apcC/wtC) were investigated (n = 6-14 per group). Three months after surgical manipulation, 10 cm of terminal ileum were excised, fixed for 48 h in 4% paraformaldehyde and all tumors were counted and their area determined in mm(2) (mean ± standard error of the mean (SEM)). Whole mounts of the muscularis of terminal ileum and duodenum (internal positive control) were also stained for tyrosine hydroxylase to confirm successful sympathetic denervation. Tumor count in Apc(Min/+) mice was 62 ± 8 (apcC), 46 ± 11 (apcV) and 54 ± 8 (apcS) which was increased compared to wildtype controls with 4 ± 0.5 (wtC), 5 ± 0.5 (wtV) and 5 ± 0.6 (wtS; all p < 0.05). For Apc(Min/+) groups, vagotomized animals showed a trend towards decreased tumor counts compared to sham operated Apc(Min/+) controls while sympathetic denervation was similar to sham Apc(Min/+). Area covered by tumors in Apc(Min/+) mice was 55 ± 10 (apcC), 31 ± 8 (apcV) and 42 ± 8 (apcS) mm(2), which was generally increased compared to wildtype controls with 7 ± 0.6 (wtC), 7 ± 0.4 (wtV) and 7 ± 0.6 (wtS) mm(2) (all p < 0.05). In Apc(Min/+) groups, tumor area was decreased in vagotomized animals compared to sham operated controls (p < 0.05) while sympathetically denervated mice showed a minor trend to decreased tumor area compared to controls. Extrinsic innervation of the small bowel is likely to modulate tumor development in Apc(Min/+) mice

  3. [The role of resistance to C active protein (R-APC) in a pediatric stroke].

    PubMed

    Cardo, E; Campistol, J; Kirkham, F

    1997-10-01

    Activated protein C resistance is a recently identified thrombophylic state which results from a mutation in the factor V gene and has been shown to be an important risk factor for peripheral venous thrombosis. We report a case of paediatric stroke in whom we have identified APC resistance. A boy presented acutely at the age of 6 years with a severe right sided headache, vomiting, unsteadiness and drowsiness which worsened over a period of 40 hours. Prior to this episode, he was neurologically and developmentally normal except for occasional headaches. CT showed low attenuation in the left cerebellar hemisphere, and occipital lobe associated with acute hydrocephalus. Excision biopsy of the left cerebellar cortex revealed inflammation and possible infarction. Although he remained in a 'locked-in' state with a flaccid quadriparesis for six months, he improved and was left with a left side hemiplegia, multiple cranial nerve palsies and a visual field defect. He represented at the age of thirteen years with transient ischaemic attacks and was found be heterozygous for the factor V Leiden mutation. Since he has been warfarinised, his symptoms have improved. Although cerebellar stroke in childhood is rare, it has been underdiagnosed in the past. As recurrence is common, patients should be fully investigated and followed up long term. Screening for new factor such as APC-resistance is recommended.

  4. Bam and Bgcn in Drosophila germline stem cell differentiation.

    PubMed

    Perinthottathil, Sreejith; Kim, Changsoo

    2011-01-01

    The female Drosophila reproductive organ, the ovary, has provided researchers with an incisive genetic system with which principle regulation of stem cell maintenance and differentiation has been delineated. An environmental niche regulates a stem cell's asymmetric self-renewal division that produces a daughter stem cell and a differentiated daughter cell, which further differentiate into eggs. A number of extrinsic and intrinsic factors have been identified that are required either for stem cell maintenance or differentiation. Bam/Bgcn complex plays a pivotal role in promoting stem cell differentiation. Recent papers suggest that Bam/Bgcn complex regulates translation of important maintenance factors and is also involved in the regulation of microRNA-dependent translational repression. Here, we focus on Bam and Bgcn repression of stem cell maintenance factors in the differentiation of germline stem cells (GSCs).

  5. Cellular factors targeting APCs to modulate adaptive T cell immunity.

    PubMed

    Visperas, Anabelle; Do, Jeongsu; Min, Booki

    2014-01-01

    The fate of adaptive T cell immunity is determined by multiple cellular and molecular factors, among which the cytokine milieu plays the most important role in this process. Depending on the cytokines present during the initial T cell activation, T cells become effector cells that produce different effector molecules and execute adaptive immune functions. Studies thus far have primarily focused on defining how these factors control T cell differentiation by targeting T cells themselves. However, other non-T cells, particularly APCs, also express receptors for the factors and are capable of responding to them. In this review, we will discuss how APCs, by responding to those cytokines, influence T cell differentiation and adaptive immunity.

  6. Recombinant HIV envelope proteins fail to engage germline versions of anti-CD4bs bNAbs.

    PubMed

    Hoot, Sam; McGuire, Andrew T; Cohen, Kristen W; Strong, Roland K; Hangartner, Lars; Klein, Florian; Diskin, Ron; Scheid, Johannes F; Sather, D Noah; Burton, Dennis R; Stamatatos, Leonidas

    2013-01-01

    Vaccine candidates for HIV-1 so far have not been able to elicit broadly neutralizing antibodies (bNAbs) although they express the epitopes recognized by bNAbs to the HIV envelope glycoprotein (Env). To understand whether and how Env immunogens interact with the predicted germline versions of known bNAbs, we screened a large panel (N:56) of recombinant Envs (from clades A, B and C) for binding to the germline predecessors of the broadly neutralizing anti-CD4 binding site antibodies b12, NIH45-46 and 3BNC60. Although the mature antibodies reacted with diverse Envs, the corresponding germline antibodies did not display Env-reactivity. Experiments conducted with engineered chimeric antibodies combining the mature and germline heavy and light chains, respectively and vice-versa, revealed that both antibody chains are important for the known cross-reactivity of these antibodies. Our results also indicate that in order for b12 to display its broad cross-reactivity, multiple somatic mutations within its VH region are required. A consequence of the failure of the germline b12 to bind recombinant soluble Env is that Env-induced B-cell activation through the germline b12 BCR does not take place. Our study provides a new explanation for the difficulties in eliciting bNAbs with recombinant soluble Env immunogens. Our study also highlights the need for intense efforts to identify rare naturally occurring or engineered Envs that may engage the germline BCR versions of bNAbs.

  7. Dietary restriction enhances germline stem cell maintenance

    PubMed Central

    Mair, William; McLeod, Catherine J.; Wang, Lei; Jones, D. Leanne

    2010-01-01

    Summary Dietary restriction (DR) increases lifespan in species ranging from yeast to primates, maintaining tissues in a youthful state and delaying reproductive senescence. However, little is known about the mechanisms by which this occurs. Here we demonstrate that, concurrent with extending lifespan, DR attenuates the age-related decline in male germline stem cell (GSC) number in Drosophila. These data support a model whereby DR enhances maintenance of GSCs to extend the reproductive period of animals subjected to adverse nutritional conditions. This represents the first example of DR maintaining an adult stem cell pool and suggests a potential mechanism by which DR might delay aging in the tissues of higher organisms. PMID:20569233

  8. Translational control in germline stem cell development

    PubMed Central

    Slaidina, Maija

    2014-01-01

    Stem cells give rise to tissues and organs during development and maintain their integrity during adulthood. They have the potential to self-renew or differentiate at each division. To ensure proper organ growth and homeostasis, self-renewal versus differentiation decisions need to be tightly controlled. Systematic genetic studies in Drosophila melanogaster are revealing extensive regulatory networks that control the switch between stem cell self-renewal and differentiation in the germline. These networks, which are based primarily on mutual translational repression, act via interlocked feedback loops to provide robustness to this important fate decision. PMID:25313405

  9. Germline energetics, aging, and female infertility.

    PubMed

    Tilly, Jonathan L; Sinclair, David A

    2013-06-04

    The role of metabolism in ovarian aging is poorly described, despite the fact that ovaries fail earlier than most other organs. Growing interest in ovarian function is being driven by recent evidence that mammalian females routinely generate new oocytes during adult life through the activity of germline stem cells. In this perspective, we overview the female reproductive system as a powerful and clinically relevant model to understand links between aging and metabolism, and we discuss new concepts for how oocytes and their precursor cells might be altered metabolically to sustain or increase ovarian function and fertility in women. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. A population-based analysis of germline BAP1 mutations in melanoma.

    PubMed

    O'Shea, Sally J; Robles-Espinoza, Carla Daniela; McLellan, Lauren; Harrigan, Jeanine; Jacq, Xavier; Hewinson, James; Iyer, Vivek; Merchant, Will; Elliott, Faye; Harland, Mark; Timothy Bishop, D; Newton-Bishop, Julia; Adams, David J

    2017-01-05

    Germline mutation of the BRCA1 associated protein-1 (BAP1) gene has been linked to uveal melanoma, mesothelioma, meningioma, renal cell carcinoma and basal cell carcinoma. Germline variants have also been found in familial cutaneous melanoma pedigrees, but their contribution to sporadic melanoma has not been fully assessed. We sequenced BAP1 in 1,977 melanoma cases and 754 controls and used deubiquitinase assays, a pedigree analysis, and a histopathological review to assess the consequences of the mutations found. Sequencing revealed 30 BAP1 variants in total, of which 27 were rare (ExAc allele frequency <0.002). Of the 27 rare variants, 22 were present in cases (18 missense, one splice acceptor, one frameshift and two near splice regions) and 5 in controls (all missense). A missense change (S98R) in a case that completely abolished BAP1 deubiquitinase activity was identified. Analysis of cancers in the pedigree of the proband carrying the S98R variant and in two other pedigrees carrying clear loss-of-function alleles showed the presence of BAP1-associated cancers such as renal cell carcinoma, mesothelioma and meningioma, but not uveal melanoma. Two of these three probands carrying BAP1 loss-of-function variants also had melanomas with histopathological features suggestive of a germline BAP1 mutation. The remaining cases with germline mutations, which were predominantly missense mutations, were associated with less typical pedigrees and tumours lacking a characteristic BAP1-associated histopathological appearances, but may still represent less penetrant variants. Germline BAP1 alleles defined as loss-of-function or predicted to be deleterious/damaging are rare in melanoma.

  11. First report of a de novo germline mutation in the MLH1 gene.

    PubMed

    Stulp, Rein P; Vos, Yvonne J; Mol, Bart; Karrenbeld, Arend; de Raad, Monique; van der Mijle, Huub J C; Sijmons, Rolf H

    2006-02-07

    Hereditary non-polyposis colorectal carcinoma (HNPCC) is an autosomal dominant disorder associated with colorectal and endometrial cancer and a range of other tumor types. Germline mutations in the DNA mismatch repair (MMR) genes, particularly MLH1, MSH2, and MSH6, underlie this disorder. The vast majority of these HNPCC-associated mutations have been proven, or assumed, given the family history of cancer, to be transmitted through several generations. To the best of our knowledge, only a single case of a de novo germline MMR gene mutation (in MSH2) has been reported till now. Here, we report a patient with a de novo mutation in MLH1. We identified a MLH1 Q701X truncating mutation in the blood lymphocytes of a male who had been diagnosed with rectal cancer at the age of 35. His family history of cancer was negative for the first- and second-degree relatives. The mutation could not be detected in the patient' parents and sibling and paternity was confirmed with a set of highly polymorphic markers. Non-penetrance and small family size is the common explanation of verified negative family histories of cancer in patients with a germline MMR gene mutation. However, in addition to some cases explained by non-paternity, de novo germline mutations should be considered as a possible explanation as well. As guidelines that stress not to restrict MMR gene mutation testing to patients with a positive family history are more widely introduced, more cases of de novo MMR gene germline mutations may be revealed.

  12. APC, K-ras, and p53 gene mutations in colorectal cancer patients: correlation to clinicopathologic features and postoperative surveillance.

    PubMed

    Hsieh, Jan-Sing; Lin, Shiu-Ru; Chang, Mei-Yin; Chen, Fang-Ming; Lu, Chien-Yu; Huang, Tsung-Jen; Huang, Yu-Sheng; Huang, Che-Jen; Wang, Jaw-Yuan

    2005-04-01

    Current researches have proposed a genetic model for colorectal cancer (CRC), in which the sequential accumulation of mutations in specific cancer-related genes, including adenomatous polyposis coli (APC), K-ras, and p53, drives the transition from normal epithelium through increasing adenomatous dysplasia to colorectal cancer. To identify patients with an increased risk of tumor recurrence or metastasis and evaluate the prognostic values of APC, K-ras, and p53 gene mutations, we investigated the frequency of these three mutated genes in tumors and sera of CRC patients. APC, K-ras, and p53 gene mutations in primary tumor tissues and their paired preoperative serum samples of 118 CRC patients were detected by using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, followed by direct DNA sequencing of the PCR-amplified genomic DNA. Subsequently, serum molecular markers were analyzed for their correlation with patients' clinicopathologic features and presence of postoperative recurrence/metastasis. We did not observe any significant difference in the association of APC or K-ras or p53 gene mutations in primary tumors with patients' demographic data (all were P > 0.05). In contrast, both serum APC and p53 molecular markers were closely correlated with lymph node metastasis and TNM stage (both P < 0.05). Moreover, the serum overall molecular markers (at least one of the three markers) were prominently associated with depth of tumor invasion (P = 0.033), lymph node metastasis (P < 0.001), and TNM stage (P < 0.001). In addition, a significantly higher postoperative metastasis/recurrence rate in patients positive for overall molecular markers compared to those negative for these molecular markers were also demonstrated (P < 0.001). APC and K-ras molecular markers were more frequently observed in patients with locoregional metastasis (both P < 0.05), while p53 molecular marker was usually detected in the cases of peritoneal metastasis (P

  13. Molecular basis of APC/C regulation by the spindle assembly checkpoint

    PubMed Central

    Zhang, Ziguo; Yang, Jing; Maslen, Sarah; Skehel, Mark; Barford, David

    2016-01-01

    In the dividing eukaryotic cell the spindle assembly checkpoint (SAC) ensures each daughter cell inherits an identical set of chromosomes. The SAC coordinates the correct attachment of sister chromatid kinetochores to the mitotic spindle with activation of the anaphase-promoting complex/cyclosome (APC/C), the E3 ubiquitin ligase that initiates chromosome separation. In response to unattached kinetochores, the SAC generates the mitotic checkpoint complex (MCC), a multimeric assembly that inhibits the APC/C, delaying chromosome segregation. Here, using cryo-electron microscopy we determined the near-atomic resolution structure of an APC/C-MCC complex (APC/CMCC). We reveal how degron-like sequences of the MCC subunit BubR1 block degron recognition sites on Cdc20, the APC/C coactivator subunit (Cdc20APC/C) responsible for substrate interactions. BubR1 also obstructs binding of UbcH10 (APC/C’s initiating E2) to repress APC/C ubiquitination activity. Conformational variability of the complex allows for UbcH10 association, and we show from a structure of APC/CMCC in complex with UbcH10 how the Cdc20 subunit intrinsic to the MCC (Cdc20MCC) is ubiquitinated, a process that results in APC/C reactivation when the SAC is silenced. PMID:27509861

  14. Clinicopathologic characteristics of anterior prostate cancer (APC), including correlation with previous biopsy pathology.

    PubMed

    Magers, Martin J; Zhan, Tianyu; Udager, Aaron M; Wei, John T; Tomlins, Scott A; Wu, Angela J; Kunju, Lakshmi P; Lew, Madelyn; Feng, Felix Y; Hamstra, Daniel A; Siddiqui, Javed; Chinnaiyan, Arul M; Montgomery, Jeffrey S; Weizer, Alon Z; Morgan, Todd M; Hollenbeck, Brent K; Miller, David C; Palapattu, Ganesh S; Jiang, Hui; Mehra, Rohit

    2015-11-01

    Anterior-predominant prostate cancer (APC) is an incompletely understood entity which can be difficult to sample via transrectal biopsy. Seemingly favorable biopsy results may belie the potential aggressiveness of these tumors. Here, we attempt to characterize APC by retrospectively examining the clinicopathologic features of APC at radical prostatectomy and comparing our findings with prior biopsy information. We found that 17.4 % of patients in our study had APC. APC demonstrated a significantly lower (P value < 0.05) Gleason score (GS) and pathologic stage than non-APC tumors, including the absence of seminal vesicle invasion by APC. A subset (5.6 %) of APC consisted of high-grade tumors (GS ≥ 8), and these tumors were more often detected on transperineal saturation biopsy than non-transperineal saturation (i.e., transrectal ultrasound guided) biopsy strategies. Four patients (7 %) without transperineal saturation biopsy exhibited a significantly worse GS at RP than biopsy, compared to five patients (36 %) with transperineal saturation biopsy. Our findings corroborate the difficulty in detecting APC and suggest that APC is not a uniform disease with a wholly indolent phenotype. Dedicated long-term outcome data are needed in these patients. Additionally, alternative pathologic staging parameters may be necessary.

  15. Altered intestinal epithelium-associated lymphocyte repertoires and function in ApcMin/+ mice.

    PubMed

    Marsh, Lorraine; Coletta, P Louise; Hull, Mark A; Selby, Peter J; Carding, Simon R

    2012-01-01

    ApcMin/+ mice spontaneously develop multiple intestinal adenomas along the length of the small intestine and colon. Currently little is known about the role of the immune system in regulating intestinal tumorigenesis in these animals. This study characterised small intestinal intraepithelial lympho-- cyte (IEL) populations in C56BL/6J ApcMin/+ mice and wild-type (Apc+/+) mice. We also determined the effect that T cells expressing either γδ or αβ encoded T cell receptors (TcR) exert on intestinal tumorigenesis. ApcMin/+ mice had significantly lower numbers of CD3+ IELs compared with Apc+/+ littermates and displayed reduced cytotoxicity against tumour target cells. Further analysis of IEL cytotoxicity revealed differences in the cytotoxic pathways utilised by IELs in ApcMin/+ and Apc+/+ mice with ApcMin/+ IELs displaying an absence of perforin/granzyme-mediated killing and increased levels of Fas-FasL-mediated cytotoxicity compared with wild-type IELs. Analysis of ApcMin/+ mice crossed with αβ T-cell deficient (TcRβ-/-) or γδ T-cell deficient (TcRδ-/-) mice on the same genetic background revealed decreased tumour multiplicity in the absence of both αβ and γδ T-cells. This study demonstrates that altered T-cell subsets play important roles in promoting tumorigenesis in ApcMin/+ mice and forms the basis for future mechanistic studies.

  16. The tissue effect of argon-plasma coagulation with prior submucosal injection (Hybrid-APC) versus standard APC: A randomized ex-vivo study

    PubMed Central

    Neugebauer, Alexander; Scharpf, Marcus; Braun, Kirsten; May, Andrea; Ell, Christian; Fend, Falko; Enderle, Markus D

    2014-01-01

    Background Thermal ablation for Barrett’s oesophagus has widely been established in gastrointestinal endoscopy during the last decade. The mainly used methods of radiofrequency ablation (RFA) and argon-plasma coagulation (APC) carry a relevant risk of stricture formation of up to 5–15%. Newer ablation techniques that are able to overcome this disadvantage would therefore be desirable. The aim of the present study was to compare the depth of tissue injury of the new method of Hybrid-APC versus standard APC within a randomized study in a porcine oesophagus model. Methods Using a total of eight explanted pig oesophagi, 48 oesophageal areas were ablated either by standard or Hybrid-APC (APC with prior submucosal fluid injection) using power settings of 50 and 70 W. The depth of tissue injury to the oesophageal wall was analysed macroscopically and histopathologically. Results Using 50 W, mean coagulation depth was 937 ± 469 µm during standard APC, and 477 ± 271 µm during Hybrid-APC (p = 0.064). Using 70 W, coagulation depth was 1096 ± 320 µm (standard APC) and 468 ± 136 µm (Hybrid-APC; p = 0.003). During all settings, damage to the muscularis mucosae was observed. Using standard APC, damage to the submucosal layer was observed in 4/6 (50 W) and 6/6 cases (70 W). During Hybrid-APC, coagulation of the submucosal layer occurred in 2/6 (50 W) and 1/6 cases (70 W). The proper muscle layer was only damaged during conventional APC (50 W: 1/6; 70 W: 3/6). Limitations Ex-vivo animal study with limited number of cases. Conclusions Hybrid-APC reduces coagulation depth by half in comparison with standard APC, with no thermal injury to the proper muscle layer. It may therefore lead to a lower rate of stricture formation during clinical application. PMID:25360316

  17. Regulation of the metabolite profile by an APC gene mutation in colorectal cancer.

    PubMed

    Yoshie, Tomoo; Nishiumi, Shin; Izumi, Yoshihiro; Sakai, Aya; Inoue, Jun; Azuma, Takeshi; Yoshida, Masaru

    2012-06-01

    Mutation of the APC gene occurs during the early stages of colorectal cancer development. To obtain new insights into the mechanisms underlying the aberrant activation of the Wnt pathway that accompanies APC mutation, we carried out a gas chromatography-mass spectrometry-based semiquantitative metabolome analysis. In vitro experiments comparing SW480 cells expressing normal APC and truncated APC indicated that the levels of metabolites involved in the latter stages of the intracellular tricarboxylic acid cycle, including succinic acid, fumaric acid, and malic acid, were significantly higher in the SW480 cells expressing the truncated APC. In an in vivo study, we found that the levels of most amino acids were higher in the non-polyp tissues of APC(min/+) mice than in the normal tissues of the control mice and the polyp tissues of APC(min/+) mice. Ribitol, the levels of which were decreased in the polyp lesions of the APC(min/+) mice and the SW480 cells expressing the truncated APC, reduced the growth of SW480 cells with the APC mutation, but did not affect the growth of SW480 transfectants expressing full-length APC. The level of sarcosine was found to be significantly higher in the polyp tissues of APC(min/+) mice than in their non-polyp tissues and the normal tissues of the control mice, and the treatment of SW480 cells with 50 μM sarcosine resulted in a significant increase in their growth rate. These findings suggest that APC mutation causes changes in energetic metabolite pathways and that these alterations might be involved in the development of colorectal cancer.

  18. EGO-1, a Putative RNA-Directed RNA Polymerase, Promotes Germline Proliferation in Parallel With GLP-1/Notch Signaling and Regulates the Spatial Organization of Nuclear Pore Complexes and Germline P Granules in Caenorhabditis elegans

    PubMed Central

    Vought, Valarie E.; Ohmachi, Mitsue; Lee, Min-Ho; Maine, Eleanor M.

    2005-01-01

    Caenorhabditis elegans EGO-1, a putative cellular RNA-directed RNA polymerase, promotes several aspects of germline development, including proliferation, meiosis, and gametogenesis, and ensures a robust response to RNA interference. In C. elegans, GLP-1/Notch signaling from the somatic gonad maintains a population of proliferating germ cells, while entry of germ cells into meiosis is triggered by the GLD-1 and GLD-2 pathways. GLP-1 signaling prevents germ cells from entering meiosis by inhibiting GLD-1 and GLD-2 activity. We originally identified the ego-1 gene on the basis of a genetic interaction with glp-1. Here, we investigate the role of ego-1 in germline proliferation. Our data indicate that EGO-1 does not positively regulate GLP-1 protein levels or GLP-1 signaling activity. Moreover, GLP-1 signaling does not positively regulate EGO-1 activity. EGO-1 does not inhibit expression of GLD-1 protein in the distal germline. Instead, EGO-1 acts in parallel with GLP-1 signaling to influence the proliferation vs. meiosis fate choice. Moreover, EGO-1 and GLD-1 act in parallel to ensure germline health. Finally, the size and distribution of nuclear pore complexes and perinuclear P granules are altered in the absence of EGO-1, effects that disrupt germ cell biology per se and probably limit germline growth. PMID:15911573

  19. Report on mutation in exon 15 of the APC gene in a case of brain metastasis.

    PubMed

    Pećina-Slaus, Nives; Majić, Zeljka; Musani, Vesna; Zeljko, Martina; Cupić, Hrvoje

    2010-03-01

    The study analyzes exon 15 of the adenomatous polyposis coli gene (APC) in a 49-year-old male patient with brain metastasis. The primary site was lung carcinoma. PCR method and direct DNA sequencing of the metastasis and autologous lymphocyte samples identified the presence of a somatic mutation. The substitution was at position 5883 G-A in the metastasis tissue. The mutation was confirmed by RFLP analysis using Msp I endonuclease, since the mutation strikes the Msp I restriction site. Immunohistochemical analysis revealed the lack of protein expression of this tumor suppressor gene. The main molecular activator of the wnt pathway, beta-catenin, was expressed, and located in the nucleus. The mutation is a silent mutation that might have consequences in the creation of a new splice site. Different single-base substitutions in APC exons need not only be evaluated by the predicted change in amino acid sequence, but rather at the nucleotide level itself. In our opinion, such silent mutations should also be incorporated in mutation detection rate and validation.

  20. Structural determinants for EB1-mediated recruitment of APC and spectraplakins to the microtubule plus end

    PubMed Central

    Slep, Kevin C.; Rogers, Stephen L.; Elliott, Sarah L.; Ohkura, Hiroyuki; Kolodziej, Peter A.; Vale, Ronald D.

    2005-01-01

    EB1 is a member of a conserved protein family that localizes to growing microtubule plus ends. EB1 proteins also recruit cell polarity and signaling molecules to microtubule tips. However, the mechanism by which EB1 recognizes cargo is unknown. Here, we have defined a repeat sequence in adenomatous polyposis coli (APC) that binds to EB1's COOH-terminal domain and identified a similar sequence in members of the microtubule actin cross-linking factor (MACF) family of spectraplakins. We show that MACFs directly bind EB1 and exhibit EB1-dependent plus end tracking in vivo. To understand how EB1 recognizes APC and MACFs, we solved the crystal structure of the EB1 COOH-terminal domain. The structure reveals a novel homodimeric fold comprised of a coiled coil and four-helix bundle motif. Mutational analysis reveals that the cargo binding site for MACFs maps to a cluster of conserved residues at the junction between the coiled coil and four-helix bundle. These results provide a structural understanding of how EB1 binds two regulators of microtubule-based cell polarity. PMID:15699215

  1. APC/CCDC20 and APC/C play pivotal roles in the process of embryonic development in Artemia sinica

    PubMed Central

    Zhang, Mengchen; Yao, Feng; Luan, Hong; Zhao, Wei; Jing, Ting; Zhang, Shuang; Hou, Lin; Zou, Xiangyang

    2016-01-01

    Anaphase Promoting Complex or Cyclosome (APC/C) is a representative E3 ubiquitin ligase, triggering the transition of metaphase to anaphase by regulating degradation and ensures the exit from mitosis. Cell division cycle 20 (CDC20) and Cell division cycle 20 related protein 1 (CDH1), as co-activators of APC/C, play significant roles in the spindle assembly checkpoint, guiding ubiquitin-mediated degradation, together with CDC23. During the embryonic development of the brine shrimp, Artemia sinica, CDC20, CDH1 and CDC23 participate in cell cycle regulation, but the specific mechanisms of their activities remain unknown. Herein, the full-length cDNAs of cdc20 and cdc23 from A. sinica were cloned. Real-time PCR analyzed the expression levels of As-cdc20 and As-cdc23. The locations of CDH1, CDC20 and CDC23 showed no tissue or organ specificity. Furthermore, western blotting showed that the levels of As-CDC20, securin, cyclin B, CDK1, CDH1, CDC14B, CDC23 and geminin proteins conformed to their complicated degradation relationships during different embryo stages. Our research revealed that As-CDC20, As-CDH1 and APC mediate the mitotic progression, downstream proteins degradation and cellular differentiation in the process of embryonic development in A. sinica. PMID:27991546

  2. Heparan sulfate regulates the number and centrosome positioning of Drosophila male germline stem cells

    PubMed Central

    Levings, Daniel C.; Arashiro, Takeshi; Nakato, Hiroshi

    2016-01-01

    Stem cell division is tightly controlled via secreted signaling factors and cell adhesion molecules provided from local niche structures. Molecular mechanisms by which each niche component regulates stem cell behaviors remain to be elucidated. Here we show that heparan sulfate (HS), a class of glycosaminoglycan chains, regulates the number and asymmetric division of germline stem cells (GSCs) in the Drosophila testis. We found that GSC number is sensitive to the levels of 6-O sulfate groups on HS. Loss of 6-O sulfation also disrupted normal positioning of centrosomes, a process required for asymmetric division of GSCs. Blocking HS sulfation specifically in the niche, termed the hub, led to increased GSC numbers and mispositioning of centrosomes. The same treatment also perturbed the enrichment of Apc2, a component of the centrosome-anchoring machinery, at the hub–GSC interface. This perturbation of the centrosome-anchoring process ultimately led to an increase in the rate of spindle misorientation and symmetric GSC division. This study shows that specific HS modifications provide a novel regulatory mechanism for stem cell asymmetric division. The results also suggest that HS-mediated niche signaling acts upstream of GSC division orientation control. PMID:26792837

  3. E-cadherin is required for centrosome and spindle orientation in Drosophila male germline stem cells.

    PubMed

    Inaba, Mayu; Yuan, Hebao; Salzmann, Viktoria; Fuller, Margaret T; Yamashita, Yukiko M

    2010-08-31

    Many adult stem cells reside in a special microenvironment known as the niche, where they receive essential signals that specify stem cell identity. Cell-cell adhesion mediated by cadherin and integrin plays a crucial role in maintaining stem cells within the niche. In Drosophila melanogaster, male germline stem cells (GSCs) are attached to niche component cells (i.e., the hub) via adherens junctions. The GSC centrosomes and spindle are oriented toward the hub-GSC junction, where E-cadherin-based adherens junctions are highly concentrated. For this reason, adherens junctions are thought to provide a polarity cue for GSCs to enable proper orientation of centrosomes and spindles, a critical step toward asymmetric stem cell division. However, understanding the role of E-cadherin in GSC polarity has been challenging, since GSCs carrying E-cadherin mutations are not maintained in the niche. Here, we tested whether E-cadherin is required for GSC polarity by expressing a dominant-negative form of E-cadherin. We found that E-cadherin is indeed required for polarizing GSCs toward the hub cells, an effect that may be mediated by Apc2. We also demonstrated that E-cadherin is required for the GSC centrosome orientation checkpoint, which prevents mitosis when centrosomes are not correctly oriented. We propose that E-cadherin orchestrates multiple aspects of stem cell behavior, including polarization of stem cells toward the stem cell-niche interface and adhesion of stem cells to the niche supporting cells.

  4. Heparan sulfate regulates the number and centrosome positioning of Drosophila male germline stem cells.

    PubMed

    Levings, Daniel C; Arashiro, Takeshi; Nakato, Hiroshi

    2016-03-15

    Stem cell division is tightly controlled via secreted signaling factors and cell adhesion molecules provided from local niche structures. Molecular mechanisms by which each niche component regulates stem cell behaviors remain to be elucidated. Here we show that heparan sulfate (HS), a class of glycosaminoglycan chains, regulates the number and asymmetric division of germline stem cells (GSCs) in the Drosophila testis. We found that GSC number is sensitive to the levels of 6-O sulfate groups on HS. Loss of 6-O sulfation also disrupted normal positioning of centrosomes, a process required for asymmetric division of GSCs. Blocking HS sulfation specifically in the niche, termed the hub, led to increased GSC numbers and mispositioning of centrosomes. The same treatment also perturbed the enrichment of Apc2, a component of the centrosome-anchoring machinery, at the hub-GSC interface. This perturbation of the centrosome-anchoring process ultimately led to an increase in the rate of spindle misorientation and symmetric GSC division. This study shows that specific HS modifications provide a novel regulatory mechanism for stem cell asymmetric division. The results also suggest that HS-mediated niche signaling acts upstream of GSC division orientation control.

  5. Somatic cell encystment promotes abscission in germline stem cells following a regulated block in cytokinesis.

    PubMed

    Lenhart, Kari F; DiNardo, Stephen

    2015-07-27

    In many tissues, the stem cell niche must coordinate behavior across multiple stem cell lineages. How this is achieved is largely unknown. We have identified delayed completion of cytokinesis in germline stem cells (GSCs) as a mechanism that regulates the production of stem cell daughters in the Drosophila testis. Through live imaging, we show that a secondary F-actin ring is formed through regulation of Cofilin activity to block cytokinesis progress after contractile ring disassembly. The duration of this block is controlled by Aurora B kinase. Additionally, we have identified a requirement for somatic cell encystment of the germline in promoting GSC abscission. We suggest that this non-autonomous role promotes coordination between stem cell lineages. These findings reveal the mechanisms by which cytokinesis is inhibited and reinitiated in GSCs and why such complex regulation exists within the stem cell niche.

  6. The tumour suppressor APC promotes HIV-1 assembly via interaction with Gag precursor protein

    PubMed Central

    Miyakawa, Kei; Nishi, Mayuko; Matsunaga, Satoko; Okayama, Akiko; Anraku, Masaki; Kudoh, Ayumi; Hirano, Hisashi; Kimura, Hirokazu; Morikawa, Yuko; Yamamoto, Naoki; Ono, Akira; Ryo, Akihide

    2017-01-01

    Diverse cellular proteins and RNAs are tightly regulated in their subcellular localization to exert their local function. Here we report that the tumour suppressor adenomatous polyposis coli protein (APC) directs the localization and assembly of human immunodeficiency virus (HIV)-1 Gag polyprotein at distinct membrane components to enable the efficient production and spread of infectious viral particles. A proteomic analysis and subsequent biomolecular interaction assay reveals that the carboxyl terminus of APC interacts with the matrix region of Gag. Ectopic expression of APC, but not its familial adenomatous polyposis-related truncation mutant, prominently enhances HIV-1 production. Conversely, the depletion of APC leads to a significant decrease in membrane targeting of viral components, resulting in the severe loss of production of infectious virions. Furthermore, APC promotes the directional assembly of viral components at virological synapses, thereby facilitating cell-to-cell viral transmission. These findings reveal an unexpected role of APC in the directional spread of HIV-1. PMID:28134256

  7. OMA-1 is a P granules-associated protein that is required for germline specification in Caenorhabditis elegans embryos.

    PubMed

    Shimada, Masumi; Yokosawa, Hideyoshi; Kawahara, Hiroyuki

    2006-04-01

    In Caenorhabditis elegans, CCCH-type zinc-finger proteins have been shown to be involved in the differentiation of germ cells during embryonic development. Previously, we and others have identified novel redundant CCCH-type zinc-finger proteins, OMA-1 and OMA-2, that are involved in oocyte maturation. In this study, we report that the cytoplasmic expression level of OMA-1 protein was largely reduced after fertilization. In contrast to its cytoplasmic degradation, OMA-1 was found to accumulate exclusively on P granules in germline blastomeres during embryogenesis. A notable finding is that embryos with partially suppressed oma-1; oma-2 expression showed inappropriate germline specification, including abnormal distributions of PGL-1, MEX-1 and PIE-1 proteins. Thus, our results suggest that oma gene products are novel multifunctional proteins that participate in crucial processes for germline specification during embryonic development.

  8. Phosphorylation-triggered CUEDC2 degradation promotes UV-induced G1 arrest through APC/C(Cdh1) regulation.

    PubMed

    Zhang, Wei-Na; Zhou, Jie; Zhou, Tao; Li, Ai-Ling; Wang, Na; Xu, Jin-Jing; Chang, Yan; Man, Jiang-Hong; Pan, Xin; Li, Tao; Li, Wei-Hua; Mu, Rui; Liang, Bing; Chen, Liang; Jin, Bao-Feng; Xia, Qing; Gong, Wei-Li; Zhang, Xue-Min; Wang, Li; Li, Hui-Yan

    2013-07-02

    DNA damage triggers cell cycle arrest to provide a time window for DNA repair. Failure of arrest could lead to genomic instability and tumorigenesis. DNA damage-induced G1 arrest is generally achieved by the accumulation of Cyclin-dependent kinase inhibitor 1 (p21). However, p21 is degraded and does not play a role in UV-induced G1 arrest. The mechanism of UV-induced G1 arrest thus remains elusive. Here, we have identified a critical role for CUE domain-containing protein 2 (CUEDC2) in this process. CUEDC2 binds to and inhibits anaphase-promoting complex/cyclosome-Cdh1 (APC/C(Cdh1)), a critical ubiquitin ligase in G1 phase, thereby stabilizing Cyclin A and promoting G1-S transition. In response to UV irradiation, CUEDC2 undergoes ERK1/2-dependent phosphorylation and ubiquitin-dependent degradation, leading to APC/C(Cdh1)-mediated Cyclin A destruction, Cyclin-dependent kinase 2 inactivation, and G1 arrest. A nonphosphorylatable CUEDC2 mutant is resistant to UV-induced degradation. Expression of this stable mutant effectively overrides UV-induced G1-S block. These results establish CUEDC2 as an APC/C(Cdh1) inhibitor and indicate that regulated CUEDC2 degradation is critical for UV-induced G1 arrest.

  9. Programmed ribosomal frameshifting in the expression of the regulator of intestinal stem cell proliferation, adenomatous polyposis coli (APC)

    PubMed Central

    Barriscale, Kathy A; Firth, Andrew E; Jud, Molly C; Letsou, Anthea; Manning, Gerard

    2011-01-01

    A programmed ribosomal frameshift (PRF) in the decoding of APC (adenomatous polyposis coli) mRNA has been identified and characterized in caenorhabditis worms, Drosophila and mosquitoes. The frameshift product lacks the C-terminal approximately one-third of the product of standard decoding and instead has a short sequence encoded by the -1 frame which is just 13 residues in C. elegans, but is 125 in D. melanogaster. The frameshift site is A AAA AAC in Caenorhabditids, fruit flies and the mosquitoes studied while a variant A AAA AAA is found in some other nematodes. The predicted secondary RNA structure of the downstream stimulators varies considerably in the species studied. In the twelve sequenced Drosophila genomes, it is a long stem with a four-way junction in its loop. In the five sequenced Caenorhabditis species, it is a short RNA pseudoknot with an additional stem in loop 1. The efficiency of frameshifting varies significantly, depending on the particular stimulator within the frameshift cassette, when tested with reporter constructs in rabbit reticulocyte lysates. Phylogenetic analysis of the distribution of APC programmed ribosomal frameshifting cassettes suggests it has an ancient origin and raises questions about the possibility of synthesis of alternative protein products during expression of APC in other organisms such as humans. The origin of APC as a PRF candidate emerged from a prior study of evolutionary signatures derived from comparative analysis of the 12 fly genomes. Three other proposed PRF candidates (Xbp1, CG32736, CG14047) with switches in conservation of reading frames are likely explained by mechanisms other than PRF. PMID:21593603

  10. The APC p.I1307K polymorphism is a significant risk factor for CRC in average risk Ashkenazi Jews.

    PubMed

    Boursi, Ben; Sella, Tal; Liberman, Eliezer; Shapira, Shiran; David, Maayan; Kazanov, Diana; Arber, Nadir; Kraus, Sarah

    2013-11-01

    The p.I1307K adenomatous polyposis coli (APC) gene variant, prevalent among Ashkenazi Jews, may increase the risk for colorectal neoplasia. We studied the clinical importance of screening for this polymorphism in 3305 Israelis undergoing colonoscopy. Clinical data regarding potential risk factors for colorectal cancer (CRC) were collected from individuals undergoing colonoscopic examination at the Tel-Aviv medical center. The APC p.I1307K was detected using real-time PCR (polymerase chain reaction) from DNA extracted from peripheral mononuclear cells. The overall prevalence of the p.I1307K polymorphism was 8.0% (10.1% among Ashkenazi and 2.7% among Sephardic Jews, p<0.001). The overall adjusted odds ratio (OR) for colorectal neoplasia among carriers was 1.51 (95% confidence intervals (CI), 1.16-1.98). Among average risk Ashkenazi Jews, the adjusted OR was 1.75 (95% CI 1.26-2.45). A multiplicative interaction was identified between Ashkenazi ethnicity and APC p.I1307K carrier status (P(INTERACTION) = 0.055). The histopathological features of adenomas and carcinomas did not differ between carriers and non-carriers. The APC p.I1307K gene variant is an important risk factor for colorectal neoplasia in average risk Ashkenazi Jews. Carriers in this group should be considered for screening colonoscopy at the age of 40, to be repeated every 5 years, similar to recommendations in individuals with family history of colorectal cancer. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Frequency of somatic and germ-line mosaicism in retinoblastoma: implications for genetic counseling.

    PubMed Central

    Sippel, K C; Fraioli, R E; Smith, G D; Schalkoff, M E; Sutherland, J; Gallie, B L; Dryja, T P

    1998-01-01

    Although mosaicism can have important implications for genetic counseling of families with hereditary disorders, information regarding the incidence of mosaicism is available for only a few genetic diseases. Here we describe an evaluation of 156 families with retinoblastoma; the initial oncogenic mutation in the retinoblastoma gene had been identified in these families. In 15 ( approximately 10%) families, we were able to document mosaicism for the initial mutation in the retinoblastoma gene, either in the proband or in one of the proband's parents. The true incidence of mosaicism in this group of 156 families is probably higher than our findings indicate; in some additional families beyond the 15 we identified, mosaicism was likely but could not be proven, because somatic or germ-line DNA from key family members was unavailable. Germ-line DNA from two mosaic fathers was analyzed: in one of these, the mutation was detected in both sperm and leukocyte DNA; in the other, the mutation was detected only in sperm DNA. Our data suggest that mosaicism is more common than is generally appreciated, especially in disorders such as retinoblastoma, in which a high proportion of cases represent new mutations. The possibility of mosaicism should always be considered during the genetic counseling of newly identified families with retinoblastoma. As demonstrated here, genetic tests of germ-line DNA can provide valuable information that is not available through analysis of somatic (leukocyte) DNA. PMID:9497263

  12. Soma-Germline Interactions That Influence Germline Proliferation in Caenorhabditis elegans

    PubMed Central

    Korta, Dorota Z.; Hubbard, E. Jane Albert

    2011-01-01

    Caenorhabditis elegans boasts a short lifecycle and high fecundity, two features that make it an attractive and powerful genetic model organism. Several recent studies indicate that germline proliferation, a prerequisite to optimal fecundity, is tightly controlled over the course of development. Cell proliferation control includes regulation of competence to proliferate, a poorly understood aspect of cell fate specification, as well as cell-cycle control. Furthermore, dynamic regulation of cell proliferation occurs in response to multiple external signals. The C. elegans germ line is proving a valuable model for linking genetic, developmental, systemic, and environmental control of cell proliferation. Here, we consider recent studies that contribute to our understanding of germ cell proliferation in C. elegans. We focus primarily on somatic control of germline proliferation, how it differs at different life stages, and how it can be altered in the context of the life cycle and changes in environmental status. PMID:20225254

  13. Apc bridges Wnt/{beta}-catenin and BMP signaling during osteoblast differentiation of KS483 cells

    SciTech Connect

    Miclea, Razvan L.; Horst, Geertje van der; Robanus-Maandag, Els C.; Loewik, Clemens W.G.M.; Oostdijk, Wilma; Wit, Jan M.; Karperien, Marcel

    2011-06-10

    The canonical Wnt signaling pathway influences the differentiation of mesenchymal cell lineages in a quantitative and qualitative fashion depending on the dose of {beta}-catenin signaling. Adenomatous polyposis coli (Apc) is the critical intracellular regulator of {beta}-catenin turnover. To better understand the molecular mechanisms underlying the role of Apc in regulating the differentiation capacity of skeletal progenitor cells, we have knocked down Apc in the murine mesenchymal stem cell-like KS483 cells by stable expression of Apc-specific small interfering RNA. In routine culture, KSFrt-Apc{sub si} cells displayed a mesenchymal-like spindle shape morphology, exhibited markedly decreased proliferation and increased apoptosis. Apc knockdown resulted in upregulation of the Wnt/{beta}-catenin and the BMP/Smad signaling pathways, but osteogenic differentiation was completely inhibited. This effect could be rescued by adding high concentrations of BMP-7 to the differentiation medium. Furthermore, KSFrt-Apc{sub si} cells showed no potential to differentiate into chondrocytes or adipocytes. These results demonstrate that Apc is essential for the proliferation, survival and differentiation of KS483 cells. Apc knockdown blocks the osteogenic differentiation of skeletal progenitor cells, a process that can be overruled by high BMP signaling.

  14. [Argon plasma coagulation (APC): a new mode in gastrointestinal endoscopy--first experience].

    PubMed

    Dajcman, D; Skalicky, M; Pernat, C; Pocajt, M

    2001-01-01

    Argon plasma coagulation (APC) is a new method of non-contact electrocoagulation in which current is applied to tissues by means of ionised argon gas (argon plasma). The development of special applicators has made this method applicable for gastrointestinal endoscopy. The primary indication for APC is the treatment of hemorrhage in the gastrointestinal tract. APC has been proven to be highly effective and easily used, with clear advantages over previously used methods. This article describes the introduction of APC in Slovenia and the first experiences with this method in the clinical department of internal medicine in Maribor.

  15. Control of cell growth by the SCF and APC/C ubiquitin ligases

    PubMed Central

    Skaar, Jeffrey R.; Pagano, Michele

    2009-01-01

    The ubiquitin-proteasome system plays key roles in the control of cell growth. The cell cycle in particular is highly regulated by the functions of the SCF and APC/C ubiquitin ligases, and perturbation of their function can result in tumorigenesis. Although the SCF and APC/C complexes are well-established in growth control pathways, many aspects of their function remain unknown. Recent studies have shed light on the mechanism of SCF-mediated ubiquitination and new functions for the SCF complex and APC/C. Our expanding understanding of the roles of the SCF and APC/C complexes highlight the potential for targeted molecular therapies. PMID:19775879

  16. Controlling the response to DNA damage by the APC/C-Cdh1.

    PubMed

    de Boer, H Rudolf; Guerrero Llobet, S; van Vugt, Marcel A T M

    2016-03-01

    Proper cell cycle progression is safeguarded by the oscillating activities of cyclin/cyclin-dependent kinase complexes. An important player in the regulation of mitotic cyclins is the anaphase-promoting complex/cyclosome (APC/C), a multi-subunit E3 ubiquitin ligase. Prior to entry into mitosis, the APC/C remains inactive, which allows the accumulation of mitotic regulators. APC/C activation requires binding to either the Cdc20 or Cdh1 adaptor protein, which sequentially bind the APC/C and facilitate targeting of multiple mitotic regulators for proteasomal destruction, including Securin and Cyclin B, to ensure proper chromosome segregation and mitotic exit. Emerging data have indicated that the APC/C, particularly in association with Cdh1, also functions prior to mitotic entry. Specifically, the APC/C-Cdh1 is activated in response to DNA damage in G2 phase cells. These observations are in line with in vitro and in vivo genetic studies, in which cells lacking Cdh1 expression display various defects, including impaired DNA repair and aberrant cell cycle checkpoints. In this review, we summarize the current literature on APC/C regulation in response to DNA damage, the functions of APC/C-Cdh1 activation upon DNA damage, and speculate how APC/C-Cdh1 can control cell fate in the context of persistent DNA damage.

  17. Sequential E2s drive polyubiquitin chain assembly on APC targets.

    PubMed

    Rodrigo-Brenni, Monica C; Morgan, David O

    2007-07-13

    The anaphase-promoting complex (APC), or cyclosome, is an E3 ubiquitin-protein ligase that collaborates with E2 ubiquitin-conjugating enzymes to assemble polyubiquitin chains on proteins important for cell-cycle progression. It remains unclear how the APC - or many other E3s - promotes the multiple distinct reactions necessary for chain assembly. We addressed this problem by analyzing APC interactions with different E2s. We screened all budding yeast E2s as APC coenzymes in vitro and found that two, Ubc4 and Ubc1, are the key E2 partners for the APC. These proteins display strikingly different but complementary enzymatic behaviors: Ubc4 supports the rapid monoubiquitination of multiple lysines on APC targets, while Ubc1 catalyzes K48-linked polyubiquitin chain assembly on preattached ubiquitins. Mitotic APC function is lost in yeast strains lacking both Ubc1 and Ubc4. E2-25K, a human homolog of Ubc1, also promotes APC-dependent chain extension on preattached ubiquitins. We propose that sequential E2 proteins catalyze K48-linked polyubiquitination and thus proteasomal destruction of APC targets.

  18. Biological basis of germline mutation: comparisons of spontaneous germline mutation rates among drosophila, mouse, and human.

    PubMed

    Drost, J B; Lee, W R

    1995-01-01

    Spontaneous mutation rates per generation are similar among the three species considered here--Drosophila, mouse, and human--and are not related to time, as is often assumed. Spontaneous germline mutation rates per generation averaged among loci are less variable among species than they are among loci and tests and between gender. Mutation rates are highly variable over time in diverse lineages. Recent estimates of the number of germ cell divisions per generation are: for humans, 401 (30-year generation) in males and 31 in females; for mice, 62 (9-month generation) in males and 25 in females; and for Drosophila melanogaster, 35.5 (18-day generation) in males and 36.5 (25-day generation) in females. The relationships between germ cell division estimates of the two sexes in the three species closely reflect those between mutation rates in the sexes, although mutation rates per cell division vary among species. Whereas the overall rate per generation is constant among species, this consistency must be achieved by diverse mechanisms. Modifiers of mutation rates, on which selection might act, include germline characteristics that contribute disproportionately to the total mutation rates. The germline mutation rates between the sexes within a species are largely influenced by germ cell divisions per generation. Also, a large portion of the total mutations occur during the interval between the beginning of meiosis and differentiation of the soma from the germline. Significant genetic events contributing to mutations during this time may include meiosis, lack of DNA repair in sperm cells, methylation of CpG dinucleotides in mammalian sperm and early embryo, gonomeric fertilization, and rapid cleavage divisions.

  19. Vertebrate female germline--the acquisition of femaleness.

    PubMed

    Tanaka, Minoru

    2014-01-01

    The cellular and molecular characteristics of female germ cells have primarily been studied in the mammalian ovary. In most female mammals, all primordial germ cells (PGCs) develop into oocytes early during ovary formation, and germline stem cells are few in number or absent in postnatal ovaries (Lei L, Spradling AC. Female mice lack adult germ-line stem cells but sustain oogenesis using stable primordial follicles. Proc Natl Acad Sci USA 2013, 110:8585-8590). Research efforts in the field have largely focused on meiosis and follicular development, but a fundamental question regarding establishment of femaleness, which is very important to understand the 'female' germline, has not been discussed sufficiently. Recent work has revealed the presence of germline stem cells in the vertebrate ovary, using the teleost fish, medaka (Oryzias latipes) (Nakamura S, Kobayashi K, Nishimura T, Higashijima S, Tanaka, M. Identification of germline stem cells in the ovary of teleost medaka. Science 2010, 328:1561-1563). This discovery allows direct comparison between female and male germline stem cells and raises an interesting and heretofore unaddressed issue regarding femaleness of germline stem cells. In this article, the germ cell behavior in the ovaries of different species is reviewed and compared, the molecular mechanisms underlying the generation of female germ cells are discussed, and the relationship between female germ cells and the surrounding somatic cells is examined. © 2013 Wiley Periodicals, Inc.

  20. Methods in Molecular Biology: Germline Stem Cells | Center for Cancer Research

    Cancer.gov

    The protocols in Germline Stem Cells are intended to present selected genetic, molecular, and cellular techniques used in germline stem cell research. The book is divided into two parts. Part I covers germline stem cell identification and regulation in model organisms. Part II covers current techniques used in in vitro culture and applications of germline stem cells.

  1. Brain energy metabolism in glutamate-receptor activation and excitotoxicity: role for APC/C-Cdh1 in the balance glycolysis/pentose phosphate pathway.

    PubMed

    Rodriguez-Rodriguez, Patricia; Almeida, Angeles; Bolaños, Juan P

    2013-04-01

    Recent advances in the field of brain energy metabolism strongly suggest that glutamate receptor-mediated neurotransmission is coupled with molecular signals that switch-on glucose utilization pathways to meet the high energetic requirements of neurons. Failure to adequately coordinate energy supply for neurotransmission ultimately results in a positive amplifying loop of receptor over-activation leading to neuronal death, a process known as excitotoxicity. In this review, we revisited current concepts in excitotoxic mechanisms, their involvement in energy substrate utilization, and the signaling pathways that coordinate both processes. In particular, we have focused on the novel role played by the E3 ubiquitin ligase, anaphase-promoting complex/cyclosome (APC/C)-Cdh1, in cell metabolism. Our laboratory identified 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) -a key glycolytic-promoting enzyme- as an APC/C-Cdh1 substrate. Interestingly, APC/C-Cdh1 activity is inhibited by over-activation of glutamate receptors through a Ca(2+)-mediated mechanism. Furthermore, by inhibiting APC/C-Cdh1 activity, glutamate-receptors activation promotes PFKFB3 stabilization, leading to increased glycolysis and decreased pentose-phosphate pathway activity. This causes a loss in neuronal ability to regenerate glutathione, triggering oxidative stress and delayed excitotoxicity. Further investigation is critical to identify novel molecules responsible for the coupling of energy metabolism with glutamatergic neurotransmission and excitotoxicity, as well as to help developing new therapeutic strategies against neurodegeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Recurrent APC gene mutations in Polish FAP families

    PubMed Central

    Pławski, Andrzej; Podralska, Marta; Słomski, Ryszard

    2007-01-01

    The molecular diagnostics of genetically conditioned disorders is based on the identification of the mutations in the predisposing genes. Hereditary cancer disorders of the gastrointestinal tracts are caused by mutations of the tumour suppressor genes or the DNA repair genes. Occurrence of recurrent mutation allows improvement of molecular diagnostics. The mutation spectrum in the genes causing hereditary forms of colorectal cancers in the Polish population was previously described. In the present work an estimation of the frequency of the recurrent mutations of the APC gene was performed. Eight types of mutations occurred in 19.4% of our FAP families and these constitute 43% of all Polish diagnosed families. PMID:19725996

  3. A trellis-searched APC (adaptive predictive coding) speech coder

    SciTech Connect

    Malone, K.T. ); Fischer, T.R. . Dept. of Electrical and Computer Engineering)

    1990-01-01

    In this paper we formulate a speech coding system that incorporates trellis coded vector quantization (TCVQ) and adaptive predictive coding (APC). A method for optimizing'' the TCVQ codebooks is presented and experimental results concerning survivor path mergings are reported. Simulation results are given for encoding rates of 16 and 9.6 kbps for a variety of coder parameters. The quality of the encoded speech is deemed excellent at an encoding rate of 16 kbps and very good at 9.6 kbps. 13 refs., 2 figs., 4 tabs.

  4. APC: A New Code for Atmospheric Polarization Computations

    NASA Technical Reports Server (NTRS)

    Korkin, Sergey V.; Lyapustin, Alexei I.; Rozanov, Vladimir V.

    2014-01-01

    A new polarized radiative transfer code Atmospheric Polarization Computations (APC) is described. The code is based on separation of the diffuse light field into anisotropic and smooth (regular) parts. The anisotropic part is computed analytically. The smooth regular part is computed numerically using the discrete ordinates method. Vertical stratification of the atmosphere, common types of bidirectional surface reflection and scattering by spherical particles or spheroids are included. A particular consideration is given to computation of the bidirectional polarization distribution function (BPDF) of the waved ocean surface.

  5. Human Germline CRISPR-Cas Modification: Toward a Regulatory Framework.

    PubMed

    Evitt, Niklaus H; Mascharak, Shamik; Altman, Russ B

    2015-01-01

    CRISPR germline editing therapies (CGETs) hold unprecedented potential to eradicate hereditary disorders. However, the prospect of altering the human germline has sparked a debate over the safety, efficacy, and morality of CGETs, triggering a funding moratorium by the NIH. There is an urgent need for practical paths for the evaluation of these capabilities. We propose a model regulatory framework for CGET research, clinical development, and distribution. Our model takes advantage of existing legal and regulatory institutions but adds elevated scrutiny at each stage of CGET development to accommodate the unique technical and ethical challenges posed by germline editing.

  6. Human Germline CRISPR-Cas Modification: Toward a Regulatory Framework

    PubMed Central

    Evitt, Niklaus H.; Mascharak, Shamik; Altman, Russ B.

    2015-01-01

    CRISPR germline editing therapies (CGETs) hold unprecedented potential to eradicate hereditary disorders. However, the prospect of altering the human germline has sparked a debate over the safety, efficacy, and morality of CGETs, triggering a funding moratorium by the NIH. There is an urgent need for practical paths for the evaluation of these capabilities. We propose a model regulatory framework for CGET research, clinical development, and distribution. Our model takes advantage of existing legal and regulatory institutions but adds elevated scrutiny at each stage of CGET development to accommodate the unique technical and ethical challenges posed by germline editing. PMID:26632357

  7. Genetic disorders and the ethical status of germ-line gene therapy.

    PubMed

    Berger, E M; Gert, B M

    1991-12-01

    Recombinant DNA technology will soon allow physicians an opportunity to carry out both somatic cell- and germ-line gene therapy. While somatic cell gene therapy raises no new ethical problems, gene therapy of gametes, fertilized eggs or early embryos does raise several novel concerns. The first issue discussed here relates to making a distinction between negative and positive eugenics; the second issue deals with the evolutionary consequences of lost genetic diversity. In distinguishing between positive and negative eugenics, the concept of malady is applied as a definitional criterion for identifying genetic disorders that could qualify for germ-line therapy. Because gene replacement techniques are currently unavailable for humans, and because even if they were possible the number of people involved would be quite small, the loss of diversity concern seems moot. Finally, we discuss the issue of iatrogenic disorders associated with gene therapy and discuss several 'real world considerations.'

  8. Germline mutations in fumarate hydratase (FH) do not predispose to prostate cancer.

    PubMed

    Bevan, S; Edwards, S M; Ardern Jones, A; Dowe, A; Southgate, C; Dearnaley, D; Easton, D F; Houlston, R S; Eeles, R A

    2003-01-01

    Inherited susceptibility to prostate cancer has been linked to a number of chromosomal regions, however no genes have been unequivocally shown to underlie reported linkages. The putative gene localised to chromosome 1q42-q43, has been designated PCaP. We have recently shown that germline mutations in the fumarate hydratase (FH) gene located on 1q43 cause smooth muscle tumours and renal cell carcinoma. It is conceivable that germline FH mutations might confer an increased risk of prostate cancer and underlie linkage of prostate cancer to PCaP. To examine this proposition we have analysed the entire coding region of FH in 160 prostate cancer cases in 77 multiple case families. No pathogenic mutations in FH were identified in any of the cases. This data makes it highly unlikely that mutations in FH confer susceptibility to prostate cancer.

  9. Rare De Novo Germline Copy-Number Variation in Testicular Cancer

    PubMed Central

    Stadler, Zsofia K.; Esposito, Diane; Shah, Sohela; Vijai, Joseph; Yamrom, Boris; Levy, Dan; Lee, Yoon-ha; Kendall, Jude; Leotta, Anthony; Ronemus, Michael; Hansen, Nichole; Sarrel, Kara; Rau-Murthy, Rohini; Schrader, Kasmintan; Kauff, Noah; Klein, Robert J.; Lipkin, Steven M.; Murali, Rajmohan; Robson, Mark; Sheinfeld, Joel; Feldman, Darren; Bosl, George; Norton, Larry; Wigler, Michael; Offit, Kenneth

    2012-01-01

    Although heritable factors are an important determinant of risk of early-onset cancer, the majority of these malignancies appear to occur sporadically without identifiable risk factors. Germline de novo copy-number variations (CNVs) have been observed in sporadic neurocognitive and cardiovascular disorders. We explored this mechanism in 382 genomes of 116 early-onset cancer case-parent trios and unaffected siblings. Unique de novo germline CNVs were not observed in 107 breast or colon cancer trios or controls but were indeed found in 7% of 43 testicular germ cell tumor trios; this percentage exceeds background CNV rates and suggests a rare de novo genetic paradigm for susceptibility to some human malignancies. PMID:22863192

  10. Low prevalence of germline hMSH6 mutations in colorectal cancer families from Spain

    PubMed Central

    de Abajo, Ana Sánchez; de la Hoya, Miguel; Tosar, Alicia; Godino, Javier; Fernández, Juan Manuel; Asenjo, Jose Lopez; Villamil, Beatriz Perez; Segura, Pedro Perez; Diaz-Rubio, Eduardo; Caldes, Trinidad

    2005-01-01

    AIM: To investigate the prevalence and penetrance of hMSH6 mutations in Spanish HNPCC families that was negative for mutation in hMLH1 or hMSH2. METHODS: We used PCR-based DGGE assay and direct sequencing to screen for hMSH6 gene in 91 HNPCC families. RESULTS: we have identified 10 families with germ-line mutations in the DNA sequence. These mutations included two intronic variation, three missense mutation, one nonsense mutation, and four silent mutations. Among the 10 germ-line mutations identified in the Spanish cohort, 8 were novel, perhaps, suggesting different mutational spectra in the Spanish population. Detailed pedigrees were constructed for the three families with a possible pathogenic hMSH6 mutation. The two silent mutations H388H and L758L, detected in a person affected of colorectal cancer at age 29, produce loss of the wild-type allele in the tumor sample. Immunohistochemical analysis showed that expression of MSH6 protein was lost only in the tumors from the carriers of V878A and Q263X mutations. CONCLUSION: Altogether, our results indicate that disease-causing germ-line mutations of hMSH6 are very less frequent in Spanish HNPCC families. PMID:16270383

  11. Germline and somatic SMARCA4 mutations characterize small cell carcinoma of the ovary, hypercalcemic type.

    PubMed

    Witkowski, Leora; Carrot-Zhang, Jian; Albrecht, Steffen; Fahiminiya, Somayyeh; Hamel, Nancy; Tomiak, Eva; Grynspan, David; Saloustros, Emmanouil; Nadaf, Javad; Rivera, Barbara; Gilpin, Catherine; Castellsagué, Ester; Silva-Smith, Rachel; Plourde, François; Wu, Mona; Saskin, Avi; Arseneault, Madeleine; Karabakhtsian, Rouzan G; Reilly, Elizabeth A; Ueland, Frederick R; Margiolaki, Anna; Pavlakis, Kitty; Castellino, Sharon M; Lamovec, Janez; Mackay, Helen J; Roth, Lawrence M; Ulbright, Thomas M; Bender, Tracey A; Georgoulias, Vassilis; Longy, Michel; Berchuck, Andrew; Tischkowitz, Marc; Nagel, Inga; Siebert, Reiner; Stewart, Colin J R; Arseneau, Jocelyne; McCluggage, W Glenn; Clarke, Blaise A; Riazalhosseini, Yasser; Hasselblatt, Martin; Majewski, Jacek; Foulkes, William D

    2014-05-01

    Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is the most common undifferentiated ovarian malignancy in women under 40 years of age. We sequenced the exomes of six individuals from three families with SCCOHT. After discovering segregating deleterious germline mutations in SMARCA4 in all three families, we tested DNA from a fourth affected family, which also carried a segregating SMARCA4 germline mutation. All the familial tumors sequenced harbored either a somatic mutation or loss of the wild-type allele. Immunohistochemical analysis of these cases and additional familial and non-familial cases showed loss of SMARCA4 (BRG1) protein in 38 of 40 tumors overall. Sequencing of cases with available DNA identified at least one germline or somatic deleterious SMARCA4 mutation in 30 of 32 cases. Additionally, the SCCOHT cell line BIN-67 had biallelic deleterious mutations in SMARCA4. Our findings identify alterations in SMARCA4 as the major cause of SCCOHT, which could lead to improvements in genetic counseling and new treatment approaches.

  12. Validity of APCS score as a risk prediction score for advanced colorectal neoplasia in Chinese asymptomatic subjects: A prospective colonoscopy study.

    PubMed

    Li, Wenbin; Zhang, Lili; Hao, Jianyu; Wu, Yongdong; Lu, Di; Zhao, Haiying; Wang, Zhenjie; Xu, Tianming; Yang, Hong; Qian, Jiaming; Li, Jingnan

    2016-10-01

    The Asia-Pacific Colorectal Screening (APCS) score is a risk-stratification tool that helps predict the risk for advanced colorectal neoplasia (ACN) in asymptomatic Asian populations, but has not yet been assessed for its validity of use in Mainland China.The aim of the study was to assess the validity of APCS score in asymptomatic Chinese population, and to identify other risk factors associated with ACN.Asymptomatic subjects (N = 1010) who underwent colonoscopy screening between 2012 and 2014 in Beijing were enrolled. APCS scores based on questionnaires were used to stratify subjects into high, moderate, and average-risk tiers. Cochran-Armitage test for trend was used to assess the association between ACN and risk tiers. Univariate and multivariate logistic regression was performed with ACN as the outcome, adjusting for APCS score, body mass index, alcohol consumption, self-reported diabetes, and use of nonsteroidal anti-inflammatory drugs as independent variables.The average age was 53.5 (standard deviation 8.4) years. The prevalence of ACN was 4.1% overall, and in the high, moderate, and average-risk tiers, the prevalence was 8.8%, 2.83%, and 1.55%, respectively (P < 0.001). High-risk tier had 3.3 and 6.1-fold increased risk of ACN as compared with those in the moderate and average-risk tiers, respectively. In univariate analysis, high-risk tier, obesity, diabetes, and alcohol consumption were associated with ACN. In multivariate analysis, only high-risk tier was an independent predictor of ACN.The APCS score can effectively identify a subset of asymptomatic Chinese population at high risk for ACN. Further studies are required to identify other risk factors, and the acceptability of the score to the general population will need to be further examined.

  13. Germlining of the HIV-1 broadly neutralizing antibody domain m36

    PubMed Central

    Chen, Weizao; Li, Wei; Ying, Tianlei; Wang, Yanping; Feng, Yang; Dimitrov, Dimiter S.

    2015-01-01

    Engineered antibody domains (eAds) have emerged as a novel class of HIV-1 inhibitors and are currently under preclinical testing as promising drug candidates for prevention and therapy of HIV-1 infection. Reverse mutation of antibodies to germline sequences (germlining) could not only identify less mutated variants with lower probability of immunogenicity and other improved properties but also help elucidate their mechanisms of action. In this study, we sequentially reverted the framework (FRs) and complementary determining regions (CDRs) of m36, a human antibody heavy chain variable domain-based eAd targeting the coreceptor binding site of the viral envelope glycoprotein gp120, back to germline sequences. Two types of amino acid mutations and one region in the antibody V segment were identified that are critical for HIV-1 neutralization. These include four mutations to acidic acid residues distributed in the CDR1 and CDR2, two mutations to hydrophobic residues in the FR3 and CDR3, and partial FR2 and FR3 sequences flanking the CDR2 that are derived from a different gene family. An m36 variant with all five mutations in the FRs reverted back to germline showed slightly increased neutralizing activity against two HIV-1 isolates tested. Another variant with seven of twelve mutations in the V segment reverted retained potency within three-fold of that of the mature antibody. These results, together with an analysis of m36-gp120-CD4 docking structures, could have implications for the further development of m36 as candidate therapeutics and elucidation of its mechanism of potent and broad HIV-1 neutralization. PMID:25676867

  14. Germline mutations in FH confer predisposition to malignant pheochromocytomas and paragangliomas.

    PubMed

    Castro-Vega, Luis Jaime; Buffet, Alexandre; De Cubas, Aguirre A; Cascón, Alberto; Menara, Mélanie; Khalifa, Emmanuel; Amar, Laurence; Azriel, Sharona; Bourdeau, Isabelle; Chabre, Olivier; Currás-Freixes, Maria; Franco-Vidal, Valérie; Guillaud-Bataille, Marine; Simian, Christophe; Morin, Aurélie; Letón, Rocío; Gómez-Graña, Alvaro; Pollard, Patrick J; Rustin, Pierre; Robledo, Mercedes; Favier, Judith; Gimenez-Roqueplo, Anne-Paule

    2014-05-01

    Malignant pheochromocytoma (PCC) and paraganglioma (PGL) are mostly caused by germline mutations of SDHB, encoding a subunit of succinate dehydrogenase. Using whole-exome sequencing, we recently identified a mutation in the FH gene encoding fumarate hydratase, in a PCC with an 'SDH-like' molecular phenotype. Here, we investigated the role of FH in PCC/PGL predisposition, by screening for germline FH mutations in a large international cohort of patients. We screened 598 patients with PCC/PGL without mutations in known PCC/PGL susceptibility genes. We searched for FH germline mutations and large deletions, by direct sequencing and multiplex ligation-dependent probe amplification methods. Global alterations in DNA methylation and protein succination were assessed by immunohistochemical staining for 5-hydroxymethylcytosine (5-hmC) and S-(2-succinyl) cysteine (2SC), respectively. We identified five pathogenic germline FH mutations (four missense and one splice mutation) in five patients. Somatic inactivation of the second allele, resulting in a loss of fumarate hydratase activity, was demonstrated in tumors with FH mutations. Low tumor levels of 5-hmC, resembling those in SDHB-deficient tumors, and positive 2SC staining were detected in tumors with FH mutations. Clinically, metastatic phenotype (P = 0.007) and multiple tumors (P = 0.02) were significantly more frequent in patients with FH mutations than those without such mutations. This study reveals a new role for FH in susceptibility to malignant and/or multiple PCC/PGL. Remarkably, FH-deficient PCC/PGLs display the same pattern of epigenetic deregulation as SDHB-mutated malignant PCC/PGL. Therefore, we propose that mutation screening for FH should be included in PCC/PGL genetic testing, at least for tumors with malignant behavior.

  15. ELLI-1, a novel germline protein, modulates RNAi activity and P-granule accumulation in Caenorhabditis elegans

    PubMed Central

    Andralojc, Karolina M.; Kelly, Ashley L.; Tanner, Paige C.

    2017-01-01

    Germ cells contain non-membrane bound cytoplasmic organelles that help maintain germline integrity. In C. elegans they are called P granules; without them, the germline undergoes partial masculinization and aberrant differentiation. One key P-granule component is the Argonaute CSR-1, a small-RNA binding protein that antagonizes accumulation of sperm-specific transcripts in developing oocytes and fine-tunes expression of proteins critical to early embryogenesis. Loss of CSR-1 complex components results in a very specific, enlarged P-granule phenotype. In a forward screen to identify mutants with abnormal P granules, ten alleles were recovered with a csr-1 P-granule phenotype, eight of which contain mutations in known components of the CSR-1 complex (csr-1, ego-1, ekl-1, and drh-3). The remaining two alleles are in a novel gene now called elli-1 (enlarged germline granules). ELLI-1 is first expressed in primordial germ cells during mid-embryogenesis, and continues to be expressed in the adult germline. While ELLI-1 forms cytoplasmic aggregates, they occasionally dock, but do not co-localize with P granules. Instead, the majority of ELLI-1 aggregates accumulate in the shared germline cytoplasm. In elli-1 mutants, several genes that promote RNAi and P-granule accumulation are upregulated, and embryonic lethality, sterility, and RNAi resistance in a hypomorphic drh-3 allele is enhanced, suggesting that ELLI-1 functions with CSR-1 to modulate RNAi activity, P-granule accumulation, and post-transcriptional expression in the germline. PMID:28182654

  16. Germline mutations of DICER1 in Chinese women with BRCA1/BRCA2-negative familial breast cancer.

    PubMed

    Cao, W-M; Gao, Y; Yang, H-J; Xie, S-N; Meng, X-L; Pan, Z-W; Chen, Z-H; Huang, J; Ye, W-W; Shao, X-Y; Wang, X-J

    2014-12-18

    Germline mutations in identified breast cancer susceptibility genes account for less than 20% of Chinese familial breast cancers. Dicer is an essential component of the microRNA-producing machinery; germline mutations of DICER1 have been confirmed in familial pleuropulmonary blastoma, ovarian sex cord-stromal tumors, and other cancers. Low expression of DICER1 is frequently detected in breast cancer. However, whether germline mutations of DICER1 occur in familial breast cancers remain unknown. Sixty-five breast cancer probands from BRCA1/BRCA2-negative Chinese breast cancer families were screened for germline mutations in DICER1. In addition, 100 unrelated healthy females were enrolled as controls. A polymerase chain reaction sequencing assay was used to screen for mutations in coding regions and at the exon-intron boundaries of DICER1. All variants in introns were evaluated using the NNSplice software to determine the potential splicing effect. A total of 12 germline variants were found, including 11 variants in introns and 1 variant in the 3'-non-coding region. Four variants (IVS8-205 C>T, IVS11+131 delGAAA, IVS16+42 delTA, and IVS19+160 T>C) were novel. Three variants (IVS11+105 C>T, IVS16+42 delTA, and 6095 T>A) may affect splice sites. None of the observed variants appeared to be disease-related, suggesting that germline mutations in DICER1 are rare or absent in familial breast cancer patients.

  17. Selecting Patients with Ovarian Cancer for Germline BRCA Mutation Testing: Findings from Guidelines and a Systematic Literature Review.

    PubMed

    Eccles, Diana M; Balmaña, Judith; Clune, Joe; Ehlken, Birgit; Gohlke, Annegret; Hirst, Ceri; Potter, Danielle; Schroeder, Claudia; Tyczynski, Jerzy E; Gomez Garcia, Encarnacion B

    2016-02-01

    One of the most significant risk factors for the development of ovarian cancer (OC) is a genetic mutation in BRCA1 (breast cancer gene 1) or BRCA2. Here we describe the impact of previous and current guidance on BRCA testing practices and provide evidence about which characteristics best identify patients with OC and an underlying germline BRCA mutation. A search was conducted for guidelines recommending genetic testing to identify constitutional pathogenic mutations in the BRCA genes. In addition, a systematic literature search of studies published in 2003-2015 was performed to assess BRCA mutation frequency in population-based OC patients unselected for patient characteristics (personal history, family history, and Ashkenazi Jewish ethnicity) and to describe the association of patient characteristics with BRCA mutation. Exclusively, studies assessing epithelial OC or invasive epithelial OC with full-gene screening of both BRCA1 and BRCA2 mutations were evaluated. Of 15 guidelines recommending genetic testing for OC patients, only 5 do not require co-occurrence of specific patient or family characteristics. Twenty-two full publications were identified that assessed germline BRCA mutation frequency in women with OC, utilizing a range of different full mutation detection methods. Germline BRCA mutation prevalence in patients with OC was 5.8-24.8%. Using criteria recommended in guidelines that are yet to be updated, we estimated that 27.5% of all germline BRCA mutations present in patients with OC may be missed because patients do not meet appropriate criteria. With the availability of BRCA mutation-targeted therapies, identification of patients with OC with germline BRCA mutations has potential therapeutic consequences. For identified gene carriers, predictive testing to allow cancer prevention strategies, including bilateral salpingo-oophorectomy, provides wider benefit to identifying such gene carriers. Updating guidelines will increase the opportunity for

  18. Sequestration of CDH1 by MAD2L2 prevents premature APC/C activation prior to anaphase onset.

    PubMed

    Listovsky, Tamar; Sale, Julian E

    2013-10-14

    The switch from activation of the anaphase-promoting complex/cyclosome (APC/C) by CDC20 to CDH1 during anaphase is crucial for accurate mitosis. APC/C(CDC20) ubiquitinates a limited set of substrates for subsequent degradation, including Cyclin B1 and Securin, whereas APC/C(CDH1) has a broader specificity. This switch depends on dephosphorylation of CDH1 and the APC/C, and on the degradation of CDC20. Here we show, in human cells, that the APC/C inhibitor MAD2L2 also contributes to ensuring the sequential activation of the APC/C by CDC20 and CDH1. In prometaphase, MAD2L2 sequestered free CDH1 away from the APC/C. At the onset of anaphase, MAD2L2 was rapidly degraded by APC/C(CDC20), releasing CDH1 to activate the dephosphorylated APC/C. Loss of MAD2L2 led to premature association of CDH1 with the APC/C, early destruction of APC/C(CDH1) substrates, and accelerated mitosis with frequent mitotic aberrations. Thus, MAD2L2 helps to ensure a robustly bistable switch between APC/C(CDC20) and APC/C(CDH1) during the metaphase-to-anaphase transition, thereby contributing to mitotic fidelity.

  19. Sipuleucel-T: APC 8015, APC-8015, prostate cancer vaccine--Dendreon.

    PubMed

    2006-01-01

    Sipuleucel-T [APC 8015, Provenge] is an autologous, dendritic cell-based vaccine under development with Dendreon Corporation for the treatment of androgen-independent and androgen-dependent prostate cancer. It was generated using the company's active immunotherapy platform to stimulate a patient's own immune system to specifically target and destroy cancer cells, while leaving healthy cells unharmed. This approach could provide patients with a meaningful survival benefit and an improved tolerability profile over existing anticancer therapies. Sipuleucel-T selectively targets the prostate-specific antigen (PSA) known as prostatic acid phosphatase (PAP) that is expressed in approximately 95% of prostate cancers. It is produced by ex vivo exposure of dendritic cell precursors to PA 2024, a recombinant fusion protein composed of the PAP target fused to granulocyte-macrophage colony-stimulating factor (GM-CSF) and incorporated into Dendreon's proprietary Antigen Delivery Cassette. Patients are typically administered three intravenous (IV)-infusions of the vaccine over a 1-month period as a complete course of therapy. It is undergoing late-stage clinical evaluation among patients with early and advanced prostate cancer. In November 2003, Kirin Brewery returned to Dendreon the full rights to Sipuleucel-T for Asia. In exchange, Dendreon licensed patent rights relating to the use of certain HLA-DR antibodies to Kirin for $US20 million. This amended agreement enables Dendreon to complete ongoing discussions for a worldwide marketing and sales partnership for Sipuleucel-T. Similarly, Kirin is able to develop its HLA-DR monoclonal antibodies free of potential infringement claims arising from Dendreon's patent rights to HLA-DR. The licensing agreement relates to patent rights owned by Dendreon relating to monoclonal antibodies against the HLA-DR antigen. In addition, Dendreon retains rights to develop and commercialise its two existing HLA-DR monoclonal antibodies, DN 1921 and

  20. Identification of germline transcriptional regulatory elements in Aedes aegypti

    NASA Astrophysics Data System (ADS)

    Akbari, Omar S.; Papathanos, Philippos A.; Sandler, Jeremy E.; Kennedy, Katie; Hay, Bruce A.

    2014-02-01

    The mosquito Aedes aegypti is the principal vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of the alphavirus chikungunya. Vector control strategies utilizing engineered gene drive systems are being developed as a means of replacing wild, pathogen transmitting mosquitoes with individuals refractory to disease transmission, or bringing about population suppression. Several of these systems, including Medea, UDMEL, and site-specific nucleases, which can be used to drive genes into populations or bring about population suppression, utilize transcriptional regulatory elements that drive germline-specific expression. Here we report the identification of multiple regulatory elements able to drive gene expression specifically in the female germline, or in the male and female germline, in the mosquito Aedes aegypti. These elements can also be used as tools with which to probe the roles of specific genes in germline function and in the early embryo, through overexpression or RNA interference.

  1. Germline and somatic FGFR1 abnormalities in dysembryoplastic neuroepithelial tumors

    PubMed Central

    Rivera, Barbara; Gayden, Tenzin; Carrot-Zhang, Jian; Nadaf, Javad; Boshari, Talia; Faury, Damien; Zeinieh, Michele; Blanc, Romeo; Burk, David L.; Fahiminiya, Somayyeh; Bareke, Eric; Schüller, Ulrich; Monoranu, Camelia M.; Sträter, Ronald; Kerl, Kornelius; Niederstadt, Thomas; Kurlemann, Gerhard; Ellezam, Benjamin; Michalak, Zuzanna; Thom, Maria; Lockhart, Paul J.; Leventer, Richard J.; Ohm, Milou; MacGregor, Duncan; Jones, David; Karamchandani, Jason; Greenwood, Celia MT; Berghuis, Albert M.; Bens, Susanne; Siebert, Reiner; Zakrzewska, Magdalena; Liberski, Pawel P.; Zakrzewski, Krzysztof; Sisodiya, Sanjay M.; Paulus, Werner; Albrecht, Steffen; Hasselblatt, Martin; Jabado, Nada; Foulkes, William D; Majewski, Jacek

    2016-01-01

    Dysembryoplastic neuroepithelial tumor (DNET) is a benign brain tumor associated with intractable drug-resistant epilepsy. In order to identify underlying genetic alterations and molecular mechanisms, we examined three family members affected by multinodular DNETs as well as 100 sporadic tumors from 96 patients, which had been referred to us as DNETs. We performed whole-exome sequencing on 46 tumors and targeted sequencing for hotspot FGFR1 mutations and BRAF p.V600E was used on the remaining samples. FISH, copy number variation assays and Sanger sequencing were used to validate the findings. By whole exome sequencing of the familial cases, we identified a novel germline FGFR1 mutation, p.R661P. Somatic activating FGFR1 mutations (p.N546K or p.K656E) were observed in the tumor samples and further evidence for functional relevance was obtained by in silico modelling. The FGFR1 p.K656E mutation was confirmed to be in cis with the germline p.R661P variant. In 43 sporadic cases, in which the diagnosis of DNET could be confirmed on central blinded neuropathology review, FGFR1 alterations were also frequent and mainly comprised intragenic tyrosine kinase FGFR1 duplication and multiple mutants in cis (25/43; 58.1%) while BRAF p.V600E alterations were absent (0/43). In contrast, in 53 cases, in which the diagnosis of DNET was not confirmed, FGFR1 alterations were less common (10/53; 19%; p<0.0001) and hotspot BRAF p.V600E (12/53; 22.6%) (p<0.001) prevailed. We observed overexpression of phospho-ERK in FGFR1 p.R661P and p.N546K mutant expressing HEK293 cells as well as FGFR1 mutated tumor samples, supporting enhanced MAP kinase pathway activation under these conditions. In conclusion, constitutional and somatic FGFR1 alterations and MAP kinase pathway activation are key events in the pathogenesis of DNET. These findings point the way towards existing targeted therapies. PMID:26920151

  2. Germline transformation of the western corn rootworm, Diabrotica virgifera virgifera.

    PubMed

    Chu, F; Klobasa, W; Wu, P; Pinzi, S; Grubbs, N; Gorski, S; Cardoza, Y; Lorenzen, M D

    2017-04-11

    The western corn rootworm (WCR), a major pest of maize, is notorious for rapidly adapting biochemically, behaviourally and developmentally to a variety of control methods. Despite much effort, the genetic basis of WCR adaptation remains a mystery. Since transformation-based applications such as transposon tagging and enhancer trapping have facilitated genetic dissection of model species such as Drosophila melanogaster, we developed a germline-transformation system for WCR in an effort to gain a greater understanding of the basic biology of this economically important insect. Here we report the use of a fluorescent-marked Minos element to create transgenic WCR. We demonstrate that the transgenic strains express both an eye-specific fluorescent marker and piggyBac transposase. We identified insertion-site junction sequences via inverse PCR and assessed insertion copy number using digital droplet PCR (ddPCR). Interestingly, most WCR identified as transgenic via visual screening for DsRed fluorescence proved to carry multiple Minos insertions when tested via ddPCR. A total of eight unique insertion strains were created by outcrossing the initial transgenic strains to nontransgenic WCR mates. Establishing transgenic technologies for this beetle is the first step towards bringing a wide range of transformation-based tools to bear on understanding WCR biology.

  3. REMOVAL OF ARSENIC IN DRINKING WATER: ARS CFU-50 APC ELECTROFLOCCULATION AND FILTRATION WATER TREATMENT SYSTEM

    EPA Science Inventory

    ETV testing of the ARS CFU-50 APC Electroflocculation and Filtration Water Treatment System (ARS CFU-50 APC) for arsenic removal was conducted at the Town of Bernalillo Well #3 site from April 18 through May 2, 2006. The source water was chlorinated groundwater from two supply w...

  4. REMOVAL OF ARSENIC IN DRINKING WATER: ARS CFU-50 APC ELECTROFLOCCULATION AND FILTRATION WATER TREATMENT SYSTEM

    EPA Science Inventory

    ETV testing of the ARS CFU-50 APC Electroflocculation and Filtration Water Treatment System (ARS CFU-50 APC) for arsenic removal was conducted at the Town of Bernalillo Well #3 site from April 18 through May 2, 2006. The source water was chlorinated groundwater from two supply w...

  5. Detection of APC gene deletions in colorectal malignancies using quantitative PCR in a Chinese population.

    PubMed

    Fang, Zhengyu; Xiong, Yi; Li, Jiana; Liu, Li; Li, Manhui; Zhang, Wei; Shi, Lei; Wan, Jun

    2011-09-01

    The adenomatous polyposis coli (APC) gene has been shown to be involved in genetic instability and to be downregluated in several human carcinomas. The chromosome locus of APC, 5q21-22, is frequently deleted in colorectal cancers (CRCs). The functional impact of such regions needs to be extensively investigated in large amount of clinical samples. Case-matched tissues of CRC and adjacent normal epithelium (n = 134) were included in this study. Quantitative PCR was carried out to examine the copy number as well as mRNA expression of APC gene in colorectal malignancies. Our results showed that copy number deletions of APC were present in a relatively high percentage of colorectal cancer samples (26.1%, 35 out of 134). There was a positive correlation between copy number decrease of APC and tumor progression in CRCs. Furthermore, copy number loss of APC was correlated with decreased mRNA expression. However, mRNA levels of APC were also impaired in CRC samples with unaltered copy numbers, indicating that sporadic CRCs exhibit different mechanisms of APC regulation.

  6. Peptidomimetic inhibitors of APC-Asef interaction block colorectal cancer migration.

    PubMed

    Jiang, Haiming; Deng, Rong; Yang, Xiuyan; Shang, Jialin; Lu, Shaoyong; Zhao, Yanlong; Song, Kun; Liu, Xinyi; Zhang, Qiufen; Chen, Yu; Chinn, Y Eugene; Wu, Geng; Li, Jian; Chen, Guoqiang; Yu, Jianxiu; Zhang, Jian

    2017-09-01

    The binding of adenomatous polyposis coli (APC) to its receptor Asef relieves the negative intramolecular regulation of Asef and leads to aberrant cell migration in human colorectal cancer. Because of its crucial role in metastatic dissemination, the interaction between APC and Asef is an attractive target for anti-colorectal-cancer therapy. We rationally designed a series of peptidomimetics that act as potent inhibitors of the APC interface. Crystal structures and biochemical and cellular assays showed that the peptidomimetics in the APC pocket inhibited the migration of colorectal cells by disrupting APC-Asef interaction. By using the peptidomimetic inhibitor as a chemical probe, we found that CDC42 was the downstream GTPase involved in APC-stimulated Asef activation in colorectal cancer cells. Our work demonstrates the feasibility of exploiting APC-Asef interaction to regulate the migration of colorectal cancer cells, and provides what to our knowledge is the first class of protein-protein interaction inhibitors available for the development of cancer therapeutics targeting APC-Asef signaling.

  7. 42 CFR 419.31 - Ambulatory payment classification (APC) system and payment weights.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the Federal Food, Drug and Cosmetic Act. (3) The payment rate determined for an APC group in... groups. (1) CMS classifies outpatient services and procedures that are comparable clinically and in terms of resource use into APC groups. Except as specified in paragraph (a)(2) of this section, items...

  8. 42 CFR 419.31 - Ambulatory payment classification (APC) system and payment weights.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Ambulatory payment classification (APC) system and... Hospital Outpatient Services § 419.31 Ambulatory payment classification (APC) system and payment weights... OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) PROSPECTIVE PAYMENT SYSTEM FOR...

  9. 42 CFR 419.31 - Ambulatory payment classification (APC) system and payment weights.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Ambulatory payment classification (APC) system and... Hospital Outpatient Services § 419.31 Ambulatory payment classification (APC) system and payment weights... OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) PROSPECTIVE PAYMENT SYSTEM FOR...

  10. 42 CFR 419.31 - Ambulatory payment classification (APC) system and payment weights.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Ambulatory payment classification (APC) system and... Hospital Outpatient Services § 419.31 Ambulatory payment classification (APC) system and payment weights... OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) PROSPECTIVE PAYMENT SYSTEM FOR...

  11. Transgenerational epigenetic inheritance: focus on soma to germline information transfer.

    PubMed

    Sharma, Abhay

    2013-12-01

    In trangenerational epigenetic inheritance, phenotypic information not encoded in DNA sequence is transmitted across generations. In germline-dependent mode, memory of environmental exposure in parental generation is transmitted through gametes, leading to appearance of phenotypes in the unexposed future generations. The memory is considered to be encoded in epigenetic factors like DNA methylation, histone modifications and regulatory RNAs. Environmental exposure may cause epigenetic modifications in the germline either directly or indirectly through primarily affecting the soma. The latter possibility is most intriguing because it contradicts the established dogma that hereditary information flows only from germline to soma, not in reverse. As such, identification of the factor(s) mediating soma to germline information transfer in transgenerational epigenetic inheritance would be pathbreaking. Regulatory RNAs and hormone have previously been implicated or proposed to play a role in soma to germline communication in epigenetic inheritance. This review examines the recent examples of gametogenic transgenerational inheritance in plants and animals in order to assess if evidence of regulatory RNAs and hormones as mediators of information transfer is supported. Overall, direct evidence for both mobile regulatory RNAs and hormones is found to exist in plants. In animals, although involvement of mobile RNAs seems imminent, direct evidence of RNA-mediated soma to germline information transfer in transgenerational epigenetic inheritance is yet to be obtained. Direct evidence is also lacking for hormones in animals. However, detailed examination of recently reported examples of transgenerational inheritance reveals circumstantial evidence supporting a role of hormones in information transmission.

  12. Clinical Report: Germline Mosaicism in Cornelia de Lange Syndrome

    PubMed Central

    Slavin, Thomas P.; Lazebnik, Noam; Clark, Dinah M.; Vengoechea, Jaime; Cohen, Leslie; Kaur, Maninder; Konczal, Laura; Crowe, Carol A.; Corteville, Jane E.; Nowaczyk, Malgorzata J.; Byrne, Janice L.; Jackson, Laird G.; Krantz, Ian D.

    2012-01-01

    Cornelia de Lange syndrome (CdLS) is a genetic disorder associated with delayed growth, intellectual disability, limb reduction defects and characteristic facial features. Germline mosaicism has been a described mechanism for CdLS when there are several affected offspring of apparently unaffected parents. Presently, the recurrence risk for CdLS has been estimated to be as high as 1.5%; however, this figure may be an underrepresentation. We report on the molecularly defined germline mosaicism cases from a large CdLS database, representing the first large case series on germline mosaicism in CdLS. Of the 12 families, eight have been previously described; however, four have not. No one specific gene mutation, either in the NIPBL or the SMC1A gene, was associated with an increased risk for germline mosaicism. Suspected or confirmed cases of germline mosaicism in our database range from a conservative 3.4% up to 5.4% of our total cohort. In conclusion, the potential reproductive recurrence risk due to germline mosiacism should be addressed in prenatal counseling for all families who have had a previously affected pregnancy or child with CdLS. PMID:22581668

  13. The impact of germline mutations on targeted therapy.

    PubMed

    Smith, Simon A; French, Tim; Hollingsworth, Simon J

    2014-01-01

    Targeted therapies provide clinical benefit and improved therapeutic index. They have a growing prominence in patient management and focus in drug development. Their development is fuelled by our deepening knowledge of complex disease phenotypes and the need for improvement in new therapeutic efficacy. Extrapolation of the biological discovery through to new therapy targeting the causal biological variants to drive clinical gain is challenging. Here, we review the impact of germline mutations on targeted therapies. Historically, germline changes have contributed most to our understanding of disease mechanisms, drug metabolism and exposure, the latter of which has enabled safer positioning of therapies, such as clopidogrel and irinotecan. Similarly, prescreening for germline variants can avoid potentially fatal hypersensitivity reactions with abacavir. However, germline mutations continue to emerge as a central player in targeting therapeutics; ivacaftor drives partial restoration of mucus secretion in cystic fibrosis patients harbouring specific mutations, and treatment with olaparib exploits germline mutations in BRCA genes to drive synthetic lethality as an anti-cancer mechanism. Central is definition of the causal link, association or contribution to the biological variance - and that we believe it is drugable for therapeutic gain. The demand for better therapies to treat modern diseases provides the appetite for continued investigation of the biological variance associated with germline mutations, inevitably leading to increased impact on the development of targeted therapeutics.

  14. Structural basis for germline antibody recognition of HIV-1 immunogens

    PubMed Central

    Scharf, Louise; West, Anthony P; Sievers, Stuart A; Chen, Courtney; Jiang, Siduo; Gao, Han; Gray, Matthew D; McGuire, Andrew T; Scheid, Johannes F; Nussenzweig, Michel C; Stamatatos, Leonidas; Bjorkman, Pamela J

    2016-01-01

    Efforts to elicit broadly neutralizing antibodies (bNAbs) against HIV-1 require understanding germline bNAb recognition of HIV-1 envelope glycoprotein (Env). The VRC01-class bNAb family derived from the VH1-2*02 germline allele arose in multiple HIV-1–infected donors, yet targets the CD4-binding site on Env with common interactions. Modified forms of the 426c Env that activate germline-reverted B cell receptors are candidate immunogens for eliciting VRC01-class bNAbs. We present structures of germline-reverted VRC01-class bNAbs alone and complexed with 426c-based gp120 immunogens. Germline bNAb–426c gp120 complexes showed preservation of VRC01-class signature residues and gp120 contacts, but detectably different binding modes compared to mature bNAb-gp120 complexes. Unlike typical antibody-antigen interactions, VRC01–class germline antibodies exhibited preformed antigen-binding conformations for recognizing immunogens. Affinity maturation introduced substitutions increasing induced-fit recognition and electropositivity, potentially to accommodate negatively-charged complex-type N-glycans on gp120. These results provide general principles relevant to the unusual evolution of VRC01–class bNAbs and guidelines for structure-based immunogen design. DOI: http://dx.doi.org/10.7554/eLife.13783.001 PMID:26997349

  15. Modeling the Effect of APC Truncation on Destruction Complex Function in Colorectal Cancer Cells

    DOE PAGES

    Barua, Dipak; Hlavacek, William S.

    2013-09-26

    In colorectal cancer cells, APC, a tumor suppressor protein, is commonly expressed in truncated form. Truncation of APC is believed to disrupt degradation of β—catenin, which is regulated by a multiprotein complex called the destruction complex. The destruction complex comprises APC, Axin, β—catenin, serine/threonine kinases, and other proteins. The kinases CK1α and GSK–3β, which are recruited by Axin, mediate phosphorylation of β—catenin, which initiates its ubiquitination and proteosomal degradation. The mechanism of regulation of β—catenin degradation by the destruction complex and the role of truncation of APC in colorectal cancer are not entirely understood. Through formulation and analysis of amore » rule-based computational model, we investigated the regulation of β—catenin phosphorylation and degradation by APC and the effect of APC truncation on function of the destruction complex. The model integrates available mechanistic knowledge about site-specific interactions and phosphorylation of destruction complex components and is consistent with an array of published data. In this paper, we find that the phosphorylated truncated form of APC can outcompete Axin for binding to β—catenin, provided that Axin is limiting, and thereby sequester β—catenin away from Axin and the Axin-recruited kinases CK1α and GSK–3β. Full-length APC also competes with Axin for binding to β—catenin; however, full-length APC is able, through its SAMP repeats, which bind Axin and which are missing in truncated oncogenic forms of APC, to bring β—catenin into indirect association with Axin and Axin-recruited kinases. Because our model indicates that the positive effects of truncated APC on β—catenin levels depend on phosphorylation of APC, at the first 20-amino acid repeat, and because phosphorylation of this site is mediated by CK1ϵ, we suggest that CK1ϵ is a potential target for therapeutic intervention in colorectal cancer. Finally, specific

  16. Modeling the effect of APC truncation on destruction complex function in colorectal cancer cells.

    PubMed

    Barua, Dipak; Hlavacek, William S

    2013-01-01

    In colorectal cancer cells, APC, a tumor suppressor protein, is commonly expressed in truncated form. Truncation of APC is believed to disrupt degradation of β-catenin, which is regulated by a multiprotein complex called the destruction complex. The destruction complex comprises APC, Axin, β-catenin, serine/threonine kinases, and other proteins. The kinases CK1α and GSK -3β, which are recruited by Axin, mediate phosphorylation of β-catenin, which initiates its ubiquitination and proteosomal degradation. The mechanism of regulation of β-catenin degradation by the destruction complex and the role of truncation of APC in colorectal cancer are not entirely understood. Through formulation and analysis of a rule-based computational model, we investigated the regulation of β-catenin phosphorylation and degradation by APC and the effect of APC truncation on function of the destruction complex. The model integrates available mechanistic knowledge about site-specific interactions and phosphorylation of destruction complex components and is consistent with an array of published data. We find that the phosphorylated truncated form of APC can outcompete Axin for binding to β-catenin, provided that Axin is limiting, and thereby sequester β-catenin away from Axin and the Axin-recruited kinases CK1α and GSK -3β. Full-length APC also competes with Axin for binding to β-catenin; however, full-length APC is able, through its SAMP repeats, which bind Axin and which are missing in truncated oncogenic forms of APC, to bring β-catenin into indirect association with Axin and Axin-recruited kinases. Because our model indicates that the positive effects of truncated APC on β-catenin levels depend on phosphorylation of APC, at the first 20-amino acid repeat, and because phosphorylation of this site is mediated by CK1ε, we suggest that CK1ε is a potential target for therapeutic intervention in colorectal cancer. Specific inhibition of CK1ε is predicted to limit binding of

  17. Modeling the Effect of APC Truncation on Destruction Complex Function in Colorectal Cancer Cells

    SciTech Connect

    Barua, Dipak; Hlavacek, William S.

    2013-09-26

    In colorectal cancer cells, APC, a tumor suppressor protein, is commonly expressed in truncated form. Truncation of APC is believed to disrupt degradation of β—catenin, which is regulated by a multiprotein complex called the destruction complex. The destruction complex comprises APC, Axin, β—catenin, serine/threonine kinases, and other proteins. The kinases CK1α and GSK–3β, which are recruited by Axin, mediate phosphorylation of β—catenin, which initiates its ubiquitination and proteosomal degradation. The mechanism of regulation of β—catenin degradation by the destruction complex and the role of truncation of APC in colorectal cancer are not entirely understood. Through formulation and analysis of a rule-based computational model, we investigated the regulation of β—catenin phosphorylation and degradation by APC and the effect of APC truncation on function of the destruction complex. The model integrates available mechanistic knowledge about site-specific interactions and phosphorylation of destruction complex components and is consistent with an array of published data. In this paper, we find that the phosphorylated truncated form of APC can outcompete Axin for binding to β—catenin, provided that Axin is limiting, and thereby sequester β—catenin away from Axin and the Axin-recruited kinases CK1α and GSK–3β. Full-length APC also competes with Axin for binding to β—catenin; however, full-length APC is able, through its SAMP repeats, which bind Axin and which are missing in truncated oncogenic forms of APC, to bring β—catenin into indirect association with Axin and Axin-recruited kinases. Because our model indicates that the positive effects of truncated APC on β—catenin levels depend on phosphorylation of APC, at the first 20-amino acid repeat, and because phosphorylation of this site is mediated by CK1ϵ, we suggest that CK1ϵ is a potential target for therapeutic intervention in colorectal cancer. Finally, specific inhibition

  18. Modeling the Effect of APC Truncation on Destruction Complex Function in Colorectal Cancer Cells

    PubMed Central

    Barua, Dipak; Hlavacek, William S.

    2013-01-01

    In colorectal cancer cells, APC, a tumor suppressor protein, is commonly expressed in truncated form. Truncation of APC is believed to disrupt degradation of β—catenin, which is regulated by a multiprotein complex called the destruction complex. The destruction complex comprises APC, Axin, β—catenin, serine/threonine kinases, and other proteins. The kinases and , which are recruited by Axin, mediate phosphorylation of β—catenin, which initiates its ubiquitination and proteosomal degradation. The mechanism of regulation of β—catenin degradation by the destruction complex and the role of truncation of APC in colorectal cancer are not entirely understood. Through formulation and analysis of a rule-based computational model, we investigated the regulation of β—catenin phosphorylation and degradation by APC and the effect of APC truncation on function of the destruction complex. The model integrates available mechanistic knowledge about site-specific interactions and phosphorylation of destruction complex components and is consistent with an array of published data. We find that the phosphorylated truncated form of APC can outcompete Axin for binding to β—catenin, provided that Axin is limiting, and thereby sequester β—catenin away from Axin and the Axin-recruited kinases and . Full-length APC also competes with Axin for binding to β—catenin; however, full-length APC is able, through its SAMP repeats, which bind Axin and which are missing in truncated oncogenic forms of APC, to bring β—catenin into indirect association with Axin and Axin-recruited kinases. Because our model indicates that the positive effects of truncated APC on β—catenin levels depend on phosphorylation of APC, at the first 20-amino acid repeat, and because phosphorylation of this site is mediated by , we suggest that is a potential target for therapeutic intervention in colorectal cancer. Specific inhibition of is predicted to limit binding of β—catenin to truncated

  19. A Streamlined Approach to Antibody Novel Germline Allele Prediction and Validation.

    PubMed

    Wendel, Ben S; He, Chenfeng; Crompton, Peter D; Pierce, Susan K; Jiang, Ning

    2017-01-01

    Advancements in high-throughput sequencing and molecular identifier-based error correction have opened the door to antibody repertoire sequencing with single mutation precision, increasing both the breadth and depth of immune response characterization. However, improvements in sequencing technology cannot resolve one key aspect of antibody repertoire sequencing accuracy: the possibility of undocumented novel germline alleles. Somatic hypermutation (SHM) calling requires a reference germline sequence, and the antibody variable region gene alleles collected by the IMGT database, although large in number, are not comprehensive. Mismatches, resulted from single nucleotide polymorphisms or other genetic variation, between the true germline sequence and the closest IMGT allele can inflate SHM counts, leading to inaccurate antibody repertoire analysis. Here, we developed a streamlined approach to novel allele prediction and validation using bulk PBMC antibody repertoire sequencing data and targeted genomic DNA amplification and sequencing using PBMCs from only 4 ml of blood to quickly and effectively improve the fidelity of antibody repertoire analysis. This approach establishes a framework for comprehensively annotating novel alleles using a small amount of blood sample, which is extremely useful in studying young children's immune systems.

  20. Comprehensive assessment of germline chemical toxicity using the nematode Caenorhabditis elegans.

    PubMed

    Parodi, Daniela A; Damoiseaux, Robert; Allard, Patrick

    2015-02-22

    Identifying the reproductive toxicity of the thousands of chemicals present in our environment has been one of the most tantalizing challenges in the field of environmental health. This is due in part to the paucity of model systems that can (1) accurately recapitulate keys features of reproductive processes and (2) do so in a medium- to high-throughput fashion, without the need for a high number of vertebrate animals. We describe here an assay in the nematode C. elegans that allows the rapid identification of germline toxicants by monitoring the induction of aneuploid embryos. By making use of a GFP reporter line, errors in chromosome segregation resulting from germline disruption are easily visualized and quantified by automated fluorescence microscopy. Thus the screening of a particular set of compounds for its toxicity can be performed in a 96- to 384-well plate format in a matter of days. Secondary analysis of positive hits can be performed to determine whether the chromosome abnormalities originated from meiotic disruption or from early embryonic chromosome segregation errors. Altogether, this assay represents a fast first-pass strategy for the rapid assessment of germline dysfunction following chemical exposure.

  1. Spatial and Temporal Analysis of Active ERK in the C. elegans Germline

    PubMed Central

    Gervaise, Amanda L.; Arur, Swathi

    2016-01-01

    The evolutionarily conserved extracellular signal transducing RTK-RAS-ERK pathway is an important kinase-signaling cascade that controls multiple cellular and developmental processes principally via activation of ERK, the terminal kinase of the pathway. Tight regulation of ERK activity is essential for normal development and homeostasis; overly active ERK results in excessive cellular proliferation, while underactive ERK causes cell death. C. elegans is a powerful model system that has helped characterize the function and regulation of RTK-RAS-ERK signaling pathway during development. In particular, the RTK-RAS-ERK pathway is essential for C. elegans germline development, which is the focus of this method. Using antibodies specific to the active, diphosphorylated form of ERK (dpERK), the stereotypical localization pattern can be visualized within the germline. Because this pattern is both spatially and temporally controlled, the ability to reproducibly assay dpERK is useful to identify regulators of the pathway that affect dpERK signal duration and amplitude and thus germline development. Here we demonstrate how to successfully dissect, stain, and image dpERK within the C. elegans gonad. This method can be adapted for spatial localization of any signaling or structural protein in the C. elegans gonad, provided an antibody compatible with immunofluorescence is available. PMID:27929466

  2. Patterns and functional implications of rare germline variants across 12 cancer types

    PubMed Central

    Lu, Charles; Xie, Mingchao; Wendl, Michael C.; Wang, Jiayin; McLellan, Michael D.; Leiserson, Mark D. M.; Huang, Kuan-lin; Wyczalkowski, Matthew A.; Jayasinghe, Reyka; Banerjee, Tapahsama; Ning, Jie; Tripathi, Piyush; Zhang, Qunyuan; Niu, Beifang; Ye, Kai; Schmidt, Heather K.; Fulton, Robert S.; McMichael, Joshua F.; Batra, Prag; Kandoth, Cyriac; Bharadwaj, Maheetha; Koboldt, Daniel C.; Miller, Christopher A.; Kanchi, Krishna L.; Eldred, James M.; Larson, David E.; Welch, John S.; You, Ming; Ozenberger, Bradley A.; Govindan, Ramaswamy; Walter, Matthew J.; Ellis, Matthew J.; Mardis, Elaine R.; Graubert, Timothy A.; Dipersio, John F.; Ley, Timothy J.; Wilson, Richard K.; Goodfellow, Paul J.; Raphael, Benjamin J.; Chen, Feng; Johnson, Kimberly J.; Parvin, Jeffrey D.; Ding, Li

    2015-01-01

    Large-scale cancer sequencing data enable discovery of rare germline cancer susceptibility variants. Here we systematically analyse 4,034 cases from The Cancer Genome Atlas cancer cases representing 12 cancer types. We find that the frequency of rare germline truncations in 114 cancer-susceptibility-associated genes varies widely, from 4% (acute myeloid leukaemia (AML)) to 19% (ovarian cancer), with a notably high frequency of 11% in stomach cancer. Burden testing identifies 13 cancer genes with significant enrichment of rare truncations, some associated with specific cancers (for example, RAD51C, PALB2 and MSH6 in AML, stomach and endometrial cancers, respectively). Significant, tumour-specific loss of heterozygosity occurs in nine genes (ATM, BAP1, BRCA1/2, BRIP1, FANCM, PALB2 and RAD51C/D). Moreover, our homology-directed repair assay of 68 BRCA1 rare missense variants supports the utility of allelic enrichment analysis for characterizing variants of unknown significance. The scale of this analysis and the somatic-germline integration enable the detection of rare variants that may affect individual susceptibility to tumour development, a critical step toward precision medicine. PMID:26689913

  3. POLD1 Germline Mutations in Patients Initially Diagnosed with Werner Syndrome

    PubMed Central

    Lessel, Davor; Hisama, Fuki M.; Szakszon, Katalin; Saha, Bidisha; Sanjuanelo, Alexander Barrios; Salbert, Bonnie A.; Steele, Pamela D.; Baldwin, Jennifer; Brown, W. Ted; Piussan, Charles; Plauchu, Henri; Szilvássy, Judit; Horkay, Edit; Hoögel, Josef; Martin, George M.; Herr, Alan J.; Oshima, Junko; Kubisch, Christian

    2015-01-01

    Segmental progeroid syndromes are rare, heterogeneous disorders characterized by signs of premature aging affecting more than one tissue or organ. A prototypic example is the Werner syndrome (WS), caused by biallelic germline mutations in the Werner helicase gene (WRN). While heterozygous lamin A/C (LMNA) mutations are found in a few nonclassical cases of WS, another 10%–15% of patients initially diagnosed with WS do not have mutations in WRN or LMNA. Germline POLD1 mutations were recently reported in five patients with another segmental progeroid disorder: mandibular hypoplasia, deafness, progeroid features syndrome. Here, we describe eight additional patients with heterozygous POLD1 mutations, thereby substantially expanding the characterization of this new example of segmental progeroid disorders. First, we identified POLD1 mutations in patients initially diagnosed with WS. Second, we describe POLD1 mutation carriers without clinically relevant hearing impairment or mandibular underdevelopment, both previously thought to represent obligate diagnostic features. These patients also exhibit a lower incidence of metabolic abnormalities and joint contractures. Third, we document postnatal short stature and premature greying/loss of hair in POLD1 mutation carriers. We conclude that POLD1 germline mutations can result in a variably expressed and probably underdiagnosed segmental progeroid syndrome. PMID:26172944

  4. Expression Profiling Reveals Developmentally Regulated lncRNA Repertoire in the Mouse Male Germline1

    PubMed Central

    Bao, Jianqiang; Wu, Jingwen; Schuster, Andrew S.; Hennig, Grant W.; Yan, Wei

    2013-01-01

    ABSTRACT In mammals, the transcriptome of large noncoding RNAs (lncRNAs) is believed to be greater than that of messenger RNAs (mRNAs). Some lncRNAs, especially large intergenic noncoding RNAs (lincRNAs), participate in epigenetic regulation by binding chromatin-modifying protein complexes and regulating protein-coding gene expression. Given that epigenetic regulation plays a critical role in male germline development, we embarked on expression profiling of both lncRNAs and mRNAs during male germline reprogramming and postnatal development using microarray analyses. We identified thousands of lncRNAs and hundreds of lincRNAs that are either up- or downregulated at six critical time points during male germ cell development. In addition, highly regulated lncRNAs were correlated with nearby (<30 kb) mRNA gene clusters, which were also significantly up- or downregulated. Large ncRNAs can be localized to both the nucleus and cytoplasm, with nuclear lncRNAs mostly associated with key components of the chromatin-remodeling protein complexes. Our data indicate that expression of lncRNAs is dynamically regulated during male germline development and that lncRNAs may function to regulate gene expression at both transcriptional and posttranscriptional levels via genetic and epigenetic mechanisms. PMID:24048575

  5. BRCA somatic and germline mutation detection in paraffin embedded ovarian cancers by next-generation sequencing.

    PubMed

    Mafficini, Andrea; Simbolo, Michele; Parisi, Alice; Rusev, Borislav; Luchini, Claudio; Cataldo, Ivana; Piazzola, Elena; Sperandio, Nicola; Turri, Giona; Franchi, Massimo; Tortora, Giampaolo; Bovo, Chiara; Lawlor, Rita T; Scarpa, Aldo

    2016-01-12

    BRCA mutated ovarian cancers respond better to platinum-based therapy and to the recently approved PARP-inhibitors. There is the need for efficient and timely methods to detect both somatic and germline mutations using formalin-fixed paraffin-embedded (FFPE) tissues and commercially available technology. We used a commercial kit exploring all exons and 50bp exon-intron junctions of BRCA1 and BRCA2 genes, and semiconductor next-generation sequencing (NGS) on DNA from 47 FFPE samples of high-grade serous ovarian cancers. Pathogenic mutations were found in 13/47 (28%) cancers: eight in BRCA1 and five in BRCA2. All BRCA1 and two BRCA2 mutations were germline; three BRCA2 mutations were somatic. All mutations were confirmed by Sanger sequencing. To evaluate the performance of the NGS panel, we assessed its capability to detect the 6,953 variants described for BRCA1 and BRCA2 in ClinVar and COSMIC databases using callability analysis. 6,059 (87.1%) variants were identified automatically by the software; 829 (12.0%) required visual verification. The remaining 65 (0.9%) variants were uncallable, and would require 15 Sanger reactions to be resolved. Thus, the sensitivity of the NGS-panel was 99.1%. In conclusion, NGS performed with a commercial kit is highly efficient for detection of germline and somatic mutations in BRCA genes using routine FFPE tissue.

  6. Low prevalence of germline PALB2 mutations in Australian triple-negative breast cancer.

    PubMed

    Wong-Brown, Michelle W; Avery-Kiejda, Kelly A; Bowden, Nikola A; Scott, Rodney J

    2014-01-15

    Triple-negative breast cancer (TNBC) is a tumour classification that is defined by oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 receptor negativity. TNBCs share a similar gene expression profile to BRCA-mutated tumours, have been shown to carry a high proportion of BRCA mutations and have a more adverse prognosis compared to other types of breast tumours. PALB2 has been shown to be a moderate-penetrance breast cancer susceptibility gene and is involved in the same DNA damage repair pathway as BRCA1 and BRCA2; this raises the possibility that germline PALB2 mutations may be involved in the pathogenesis of TNBCs. In our study, we sequenced the coding regions of PALB2 (including intron/exon boundaries) in genomic DNA from 347 patients diagnosed with TNBC to determine the prevalence of deleterious mutations in this population. Two novel truncating mutations (c.758dup and c.2390del) and one previously detected truncating mutation (c.3113+5G>C) were found. In addition, five variants predicted to be protein-affecting were also identified. Our study shows that the prevalence of PALB2 germline mutations in individuals with TNBC is ∼1%, similar to the prevalence of PALB2 germline mutation of 1% in familial non-BRCA1/2 breast cancer cohorts.

  7. Two PALB2 germline mutations found in both BRCA1+ and BRCAx familial breast cancer.

    PubMed

    Downs, Bradley; Kim, Yeong C; Xiao, Fengxia; Snyder, Carrie; Chen, Peixian; Fleissner, Elizabeth A; Becirovic, Dina; Wen, Hongxiu; Sherman, Simon; Cowan, Kenneth H; Lynch, Henry T; Wang, San Ming

    2015-05-01

    Partner and localizer of BRCA2 (PALB2), plays an important functional role in DNA damage repair. Recent studies indicate that germline mutations in PALB2 predispose individuals to a high risk of developing familial breast cancer. Therefore, comprehensive identification of PALB2 germline mutations is potentially important for understanding their roles in tumorigenesis and for testing their potential utility as clinical targets. Most of the previous studies of PALB2 have focused on familial breast cancer cases with normal/wild-type BRCA1 and BRCA2 (BRCAx). We hypothesize that PALB2 genetic mutations also exist in individuals with BRCA mutations (BRCA+). To test this hypothesis, PALB2 germline mutations were screened in 107 exome data sets collected from familial breast cancer families who were either BRCA1+ or BRCAx. Two novel heterozygous mutations predicted to alter the function of PALB2 were identified (c.2014G>C, p.E672Q and c.2993G>A, p.G998E). Notably, both of these mutations co-existed in BRCA1+ and BRCA1x families. These studies show that mutations in PALB2 can occur independent of the status of BRCA1 mutations, and they highlight the importance to include BRCA1+ families in PALB2 mutation screens.

  8. Protein phosphatase 1ß limits ring canal constriction during Drosophila germline cyst formation.

    PubMed

    Yamamoto, Shinya; Bayat, Vafa; Bellen, Hugo J; Tan, Change

    2013-01-01

    Germline cyst formation is essential for the propagation of many organisms including humans and flies. The cytoplasm of germline cyst cells communicate with each other directly via large intercellular bridges called ring canals. Ring canals are often derived from arrested contractile rings during incomplete cytokinesis. However how ring canal formation, maintenance and growth are regulated remains unclear. To better understand this process, we carried out an unbiased genetic screen in Drosophila melanogaster germ cells and identified multiple alleles of flapwing (flw), a conserved serine/threonine-specific protein phosphatase. Flw had previously been reported to be unnecessary for early D. melanogaster oogenesis using a hypomorphic allele. We found that loss of Flw leads to over-constricted nascent ring canals and subsequently tiny mature ring canals, through which cytoplasmic transfer from nurse cells to the oocyte is impaired, resulting in small, non-functional eggs. Flw is expressed in germ cells undergoing incomplete cytokinesis, completely colocalized with the Drosophila myosin binding subunit of myosin phosphatase (DMYPT). This colocalization, together with genetic interaction studies, suggests that Flw functions together with DMYPT to negatively regulate myosin activity during ring canal formation. The identification of two subunits of the tripartite myosin phosphatase as the first two main players required for ring canal constriction indicates that tight regulation of myosin activity is essential for germline cyst formation and reproduction in D. melanogaster and probably other species as well.

  9. P53 germline mutations in childhood cancers and cancer risk for carrier individuals

    PubMed Central

    Chompret, A; Brugières, L; Ronsin, M; Gardes, M; Dessarps-Freichey, F; Abel, A; Hua, D; Ligot, L; Dondon, M-G; Paillerets, B Bressac-de; Frébourg, T; Lemerle, J; Bonaïti-Pellié, C; Feunteun, J

    2000-01-01

    The family history of cancer in children treated for a solid malignant tumour in the Paediatric Oncology Department at Institute Gustave-Roussy, has been investigated. In order to determine the role of germline p53 mutations in genetic predisposition to childhood cancer, germline p53 mutations were sought in individuals with at least one relative (first- or second-degree relative or first cousin) affected by any cancer before 46 years of age, or affected by multiple cancers. Screening for germline p53 mutation was possible in 268 index cases among individuals fulfilling selection criteria. Seventeen (6.3%) mutations were identified, of which 13 were inherited and four were de novo. Using maximum likelihood methods that incorporate retrospective family data and correct for ascertainment bias, the lifetime risk of cancer for mutation carriers was estimated to be 73% for males and nearly 100% for females with a high risk of breast cancer accounting for the difference. The risk of cancer associated with such mutations is very high and no evidence of low penetrance mutation was found. These mutations are frequently inherited but de novo mutations are not rare. © 2000 Cancer Research Campaign PMID:10864200

  10. Germline mutations in DNA repair genes predispose asbestos-exposed patients to malignant pleural mesothelioma.

    PubMed

    Betti, Marta; Casalone, Elisabetta; Ferrante, Daniela; Aspesi, Anna; Morleo, Giulia; Biasi, Alessandra; Sculco, Marika; Mancuso, Giuseppe; Guarrera, Simonetta; Righi, Luisella; Grosso, Federica; Libener, Roberta; Pavesi, Mansueto; Mariani, Narciso; Casadio, Caterina; Boldorini, Renzo; Mirabelli, Dario; Pasini, Barbara; Magnani, Corrado; Matullo, Giuseppe; Dianzani, Irma

    2017-10-01

    Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer caused by asbestos exposure. An inherited predisposition has been suggested to explain multiple cases in the same family and the observation that not all individuals highly exposed to asbestos develop the tumor. Germline mutations in BAP1 are responsible for a rare cancer predisposition syndrome that includes predisposition to mesothelioma. We hypothesized that other genes involved in hereditary cancer syndromes could be responsible for the inherited mesothelioma predisposition. We investigated the prevalence of germline variants in 94 cancer-predisposing genes in 93 MPM patients with a quantified asbestos exposure. Ten pathogenic truncating variants (PTVs) were identified in PALB2, BRCA1, FANCI, ATM, SLX4, BRCA2, FANCC, FANCF, PMS1 and XPC. All these genes are involved in DNA repair pathways, mostly in homologous recombination repair. Patients carrying PTVs represented 9.7% of the panel and showed lower asbestos exposure than did all the other patients (p = 0.0015). This suggests that they did not efficiently repair the DNA damage induced by asbestos and leading to carcinogenesis. This study shows that germline variants in several genes may increase MPM susceptibility in the presence of asbestos exposure and may be important for specific treatment. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  11. MORC-1 Integrates Nuclear RNAi and Transgenerational Chromatin Architecture to Promote Germline Immortality.

    PubMed

    Weiser, Natasha E; Yang, Danny X; Feng, Suhua; Kalinava, Natallia; Brown, Kristen C; Khanikar, Jayshree; Freeberg, Mallory A; Snyder, Martha J; Csankovszki, Györgyi; Chan, Raymond C; Gu, Sam G; Montgomery, Taiowa A; Jacobsen, Steven E; Kim, John K

    2017-05-22

    Germline-expressed endogenous small interfering RNAs (endo-siRNAs) transmit multigenerational epigenetic information to ensure fertility in subsequent generations. In Caenorhabditis elegans, nuclear RNAi ensures robust inheritance of endo-siRNAs and deposition of repressive H3K9me3 marks at target loci. How target silencing is maintained in subsequent generations is poorly understood. We discovered that morc-1 is essential for transgenerational fertility and acts as an effector of endo-siRNAs. Unexpectedly, morc-1 is dispensable for siRNA inheritance but is required for target silencing and maintenance of siRNA-dependent chromatin organization. A forward genetic screen identified mutations in met-1, which encodes an H3K36 methyltransferase, as potent suppressors of morc-1(-) and nuclear RNAi mutant phenotypes. Further analysis of nuclear RNAi and morc-1(-) mutants revealed a progressive, met-1-dependent enrichment of H3K36me3, suggesting that robust fertility requires repression of MET-1 activity at nuclear RNAi targets. Without MORC-1 and nuclear RNAi, MET-1-mediated encroachment of euchromatin leads to detrimental decondensation of germline chromatin and germline mortality. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. POLD1 Germline Mutations in Patients Initially Diagnosed with Werner Syndrome.

    PubMed

    Lessel, Davor; Hisama, Fuki M; Szakszon, Katalin; Saha, Bidisha; Sanjuanelo, Alexander Barrios; Salbert, Bonnie A; Steele, Pamela D; Baldwin, Jennifer; Brown, W Ted; Piussan, Charles; Plauchu, Henri; Szilvássy, Judit; Horkay, Edit; Högel, Josef; Martin, George M; Herr, Alan J; Oshima, Junko; Kubisch, Christian

    2015-11-01

    Segmental progeroid syndromes are rare, heterogeneous disorders characterized by signs of premature aging affecting more than one tissue or organ. A prototypic example is the Werner syndrome (WS), caused by biallelic germline mutations in the Werner helicase gene (WRN). While heterozygous lamin A/C (LMNA) mutations are found in a few nonclassical cases of WS, another 10%-15% of patients initially diagnosed with WS do not have mutations in WRN or LMNA. Germline POLD1 mutations were recently reported in five patients with another segmental progeroid disorder: mandibular hypoplasia, deafness, progeroid features syndrome. Here, we describe eight additional patients with heterozygous POLD1 mutations, thereby substantially expanding the characterization of this new example of segmental progeroid disorders. First, we identified POLD1 mutations in patients initially diagnosed with WS. Second, we describe POLD1 mutation carriers without clinically relevant hearing impairment or mandibular underdevelopment, both previously thought to represent obligate diagnostic features. These patients also exhibit a lower incidence of metabolic abnormalities and joint contractures. Third, we document postnatal short stature and premature greying/loss of hair in POLD1 mutation carriers. We conclude that POLD1 germline mutations can result in a variably expressed and probably underdiagnosed segmental progeroid syndrome.

  13. BRCA somatic and germline mutation detection in paraffin embedded ovarian cancers by next-generation sequencing

    PubMed Central

    Mafficini, Andrea; Simbolo, Michele; Parisi, Alice; Rusev, Borislav; Luchini, Claudio; Cataldo, Ivana; Piazzola, Elena; Sperandio, Nicola; Turri, Giona; Franchi, Massimo; Tortora, Giampaolo; Bovo, Chiara; Lawlor, Rita T.; Scarpa, Aldo

    2016-01-01

    BRCA mutated ovarian cancers respond better to platinum-based therapy and to the recently approved PARP-inhibitors. There is the need for efficient and timely methods to detect both somatic and germline mutations using formalin-fixed paraffin-embedded (FFPE) tissues and commercially available technology. We used a commercial kit exploring all exons and 50bp exon-intron junctions of BRCA1 and BRCA2 genes, and semiconductor next-generation sequencing (NGS) on DNA from 47 FFPE samples of high-grade serous ovarian cancers. Pathogenic mutations were found in 13/47 (28%) cancers: eight in BRCA1 and five in BRCA2. All BRCA1 and two BRCA2 mutations were germline; three BRCA2 mutations were somatic. All mutations were confirmed by Sanger sequencing. To evaluate the performance of the NGS panel, we assessed its capability to detect the 6,953 variants described for BRCA1 and BRCA2 in ClinVar and COSMIC databases using callability analysis. 6,059 (87.1%) variants were identified automatically by the software; 829 (12.0%) required visual verification. The remaining 65 (0.9%) variants were uncallable, and would require 15 Sanger reactions to be resolved. Thus, the sensitivity of the NGS-panel was 99.1%. In conclusion, NGS performed with a commercial kit is highly efficient for detection of germline and somatic mutations in BRCA genes using routine FFPE tissue. PMID:26745875

  14. Apc Restoration Promotes Cellular Differentiation and Reestablishes Crypt Homeostasis in Colorectal Cancer.

    PubMed

    Dow, Lukas E; O'Rourke, Kevin P; Simon, Janelle; Tschaharganeh, Darjus F; van Es, Johan H; Clevers, Hans; Lowe, Scott W

    2015-06-18

    The adenomatous polyposis coli (APC) tumor suppressor is mutated in the vast majority of human colorectal cancers (CRC) and leads to deregulated Wnt signaling. To determine whether Apc disruption is required for tumor maintenance, we developed a mouse model of CRC whereby Apc can be conditionally suppressed using a doxycycline-regulated shRNA. Apc suppression produces adenomas in both the small intestine and colon that, in the presence of Kras and p53 mutations, can progress to invasive carcinoma. In established tumors, Apc restoration drives rapid and widespread tumor-cell differentiation and sustained regression without relapse. Tumor regression is accompanied by the re-establishment of normal crypt-villus homeostasis, such that once aberrantly proliferating cells reacquire self-renewal and multi-lineage differentiation capability. Our study reveals that CRC cells can revert to functioning normal cells given appropriate signals and provide compelling in vivo validation of the Wnt pathway as a therapeutic target for treatment of CRC.

  15. Discovery of germline-related genes in Cephalochordate amphioxus: A genome wide survey using genome annotation and transcriptome data.

    PubMed

    Yue, Jia-Xing; Li, Kun-Lung; Yu, Jr-Kai

    2015-12-01

    The generation of germline cells is a critical process in the reproduction of multicellular organisms. Studies in animal models have identified a common repertoire of genes that play essential roles in primordial germ cell (PGC) formation. However, comparative studies also indicate that the timing and regulation of this core genetic program vary considerably in different animals, raising the intriguing questions regarding the evolution of PGC developmental mechanisms in metazoans. Cephalochordates (commonly called amphioxus or lancelets) represent one of the invertebrate chordate groups and can provide important information about the evolution of developmental mechanisms in the chordate lineage. In this study, we used genome and transcriptome data to identify germline-related genes in two distantly related cephalochordate species, Branchiostoma floridae and Asymmetron lucayanum. Branchiostoma and Asymmetron diverged more than 120 MYA, and the most conspicuous difference between them is their gonadal morphology. We used important germline developmental genes in several model animals to search the amphioxus genome and transcriptome dataset for conserved homologs. We also annotated the assembled transcriptome data using Gene Ontology (GO) terms to facilitate the discovery of putative genes associated with germ cell development and reproductive functions in amphioxus. We further confirmed the expression of 14 genes in developing oocytes or mature eggs using whole mount in situ hybridization, suggesting their potential functions in amphioxus germ cell development. The results of this global survey provide a useful resource for testing potential functions of candidate germline-related genes in cephalochordates and for investigating differences in gonad developmental mechanisms between Branchiostoma and Asymmetron species.

  16. A knock-in mouse model reveals roles for nuclear Apc in cell proliferation, Wnt signal inhibition and tumor suppression.

    PubMed

    Zeineldin, M; Cunningham, J; McGuinness, W; Alltizer, P; Cowley, B; Blanchat, B; Xu, W; Pinson, D; Neufeld, K L

    2012-05-10

    Mutation of the tumor suppressor adenomatous polyposis coli (APC) is considered an initiating step in the genesis of the vast majority of colorectal cancers. APC inhibits the Wnt-signaling pathway by targeting the proto-oncogene β-catenin for destruction by cytoplasmic proteasomes. In the presence of a Wnt signal, or in the absence of functional APC, β-catenin can serve as a transcription cofactor for genes required for cell proliferation such as cyclin-D1 and c-Myc. In cultured cells, APC shuttles between the nucleus and the cytoplasm, with nuclear APC implicated in the inhibition of Wnt target gene expression. Adopting a genetic approach to evaluate the functions of nuclear APC in the context of a whole organism, we generated a mouse model with mutations that inactivate the nuclear localization signals (NLSs) of Apc (Apc(mNLS)). Apc(mNLS/mNLS) mice are viable and fractionation of mouse embryonic fibroblasts (MEFs) isolated from these mice revealed a significant reduction in nuclear Apc as compared with Apc(+/+) MEFs. The levels of Apc and β-catenin protein were not significantly altered in small intestinal epithelia from Apc(mNLS/mNLS) mice. Compared with Apc(+/+) mice, Apc(mNLS/mNLS) mice showed increased proliferation in epithelial cells from the jejunum, ileum and colon. These same tissues from Apc(mNLS/mNLS) mice showed more mRNA from three genes upregulated in response to canonical Wnt signal, c-Myc, axin-2 and cyclin-D1, and less mRNA from Hath-1, which is downregulated in response to Wnt. These observations suggest a role for nuclear Apc in the inhibition of canonical Wnt signaling and the control of epithelial proliferation in intestinal tissue. Furthermore, we found Apc(Min/+) mice, which harbor a mutation that truncates Apc, to have an increased polyp size and multiplicity if they also carry the Apc(mNLS) allele. Taken together, this analysis of the novel Apc(mNLS) mouse model supports a role for nuclear Apc in the control of Wnt target genes

  17. Most common 'sporadic' cancers have a significant germline genetic component.

    PubMed

    Lu, Yi; Ek, Weronica E; Whiteman, David; Vaughan, Thomas L; Spurdle, Amanda B; Easton, Douglas F; Pharoah, Paul D; Thompson, Deborah J; Dunning, Alison M; Hayward, Nicholas K; Chenevix-Trench, Georgia; Macgregor, Stuart

    2014-11-15

    Common cancers have been demarcated into 'hereditary' or 'sporadic' ('non-hereditary') types historically. Such distinctions initially arose from work identifying rare, highly penetrant germline mutations causing 'hereditary' cancer. While rare mutations are important in particular families, most cases in the general population are 'sporadic'. Twin studies have suggested that many 'sporadic' cancers show little or no heritability. To quantify the role of germline mutations in cancer susceptibility, we applied a method for estimating the importance of common genetic variants (array heritability, h(2)g) to twelve cancer types. The following cancers showed a significant (P < 0.05) array heritability: melanoma USA set h(2)g = 0.19 (95% CI = 0.01-0.37) and Australian set h(2)g = 0.30 (0.10-0.50); pancreatic h(2)g = 0.18 (0.06-0.30); prostate h(2)g = 0.81 (0.32-1); kidney h(2)g = 0.18 (0.04-0.32); ovarian h(2)g = 0.30 (0.18-0.42); esophageal adenocarcinoma h(2)g = 0.24 (0.14-0.34); esophageal squamous cell carcinoma h(2)g = 0.19 (0.07-0.31); endometrial UK set h(2)g = 0.23 (0.01-0.45) and Australian set h(2)g = 0.39 (0.02-0.76). Three cancers showed a positive but non-significant effect: breast h(2) g = 0.13 (0-0.56); gastric h(2)g = 0.11 (0-0.27); lung h(2)g = 0.10 (0-0.24). One cancer showed a small effect: bladder h(2)g = 0.01 (0-0.11). Among these cancers, previous twin studies were only able to show heritability for prostate and breast cancer, but we can now make much stronger statements for several common cancers which emphasize the important role of genetic variants in cancer susceptibility. We have demonstrated that several 'sporadic' cancers have a significant inherited component. Larger genome-wide association studies in these cancers will continue to find more loci, which explain part of the remaining polygenic component.

  18. Regulation of APC(Cdh1) E3 ligase activity by the Fbw7/cyclin E signaling axis contributes to the tumor suppressor function of Fbw7.

    PubMed

    Lau, Alan W; Inuzuka, Hiroyuki; Fukushima, Hidefumi; Wan, Lixin; Liu, Pengda; Gao, Daming; Sun, Yi; Wei, Wenyi

    2013-07-01

    Fbw7 and Cdh1 are substrate-recognition subunits of the SCF- and APC-type E3 ubiquitin ligases, respectively. There is emerging evidence suggesting that both Fbw7 and Cdh1 function as tumor suppressors by targeting oncoproteins for destruction. Loss of Fbw7, but not Cdh1, is frequently observed in various human tumors. However, it remains largely unknown how Fbw7 mechanistically functions as a tumor suppressor and whether there is a signaling crosstalk between Fbw7 and Cdh1. Here, we report that Fbw7-deficient cells not only display elevated expression levels of SCF(Fbw7) substrates, including cyclin E, but also have increased expression of various APC(Cdh1) substrates. We further defined cyclin E as the critical signaling link by which Fbw7 governs APC(Cdh1) activity, as depletion of cyclin E in Fbw7-deficient cells results in decreased expression of APC(Cdh1) substrates to levels comparable to those in wild-type (WT) cells. Conversely, ectopic expression of cyclin E recapitulates the aberrant APC(Cdh1) substrate expression observed in Fbw7-deficient cells. More importantly, 4A-Cdh1 that is resistant to Cdk2/cyclin E-mediated phosphorylation, but not WT-Cdh1, reversed the elevated expression of various APC(Cdh1) substrates in Fbw7-deficient cells. Overexpression of 4A-Cdh1 also resulted in retarded cell growth and decreased anchorage-independent colony formation. Altogether, we have identified a novel regulatory mechanism by which Fbw7 governs Cdh1 activity in a cyclin E-dependent manner. As a result, loss of Fbw7 can lead to aberrant increase in the expression of both SCF(Fbw7) and APC(Cdh1) substrates. Our study provides a better understanding of the tumor suppressor function of Fbw7, and suggests that Cdk2/cyclin E inhibitors could serve as effective therapeutic agents for treating Fbw7-deficient tumors.

  19. Germline Manipulation and Our Future Worlds.

    PubMed

    Harris, John

    2015-01-01

    Two genetic technologies capable of making heritable changes to the human genome have revived interest in, and in some quarters a very familiar panic concerning, so-called germline interventions. These technologies are: most recently the use of CRISPR/Cas9 to edit genes in non-viable IVF zygotes and Mitochondrial Replacement Therapy (MRT) the use of which was approved in principle in a landmark vote earlier this year by the United Kingdom Parliament. The possibility of using either of these techniques in humans has encountered the most violent hostility and suspicion. However it is important to be aware that much of this hostility dates back to the fears associated with In Vitro Fertilization (IVF) and other reproductive technologies and by cloning; fears which were baseless at the time concerning both IVF and cloning the use of both of which have proved to be highly beneficial to humanity and which have been effectively regulated and controlled. This paper argues that CRISPR should by pursued through researh until it is safe enough for use in humans but there is no reason to suppose at this stage that such use will be unsafe or unethical (Collins 2015).

  20. The regulation of Cdc20 proteolysis reveals a role for APC components Cdc23 and Cdc27 during S phase and early mitosis.

    PubMed

    Prinz, S; Hwang, E S; Visintin, R; Amon, A

    1998-06-18

    In eukaryotic cells, a specialized proteolysis machinery that targets proteins containing destruction-box sequences for degradation and that uses a ubiquitin ligase known as the anaphase-promoting complex/cyclosome (APC) plays a key role in the regulation of mitosis. APC-dependent proteolysis triggers the separation of sister chromatids at the metaphase-anaphase transition and the destruction of mitotic cyclins at the end of mitosis. Recently, two highly conserved WD40-repeat proteins, Cdc20 and Cdh1/Hct1, have been identified as substrate-specific regulators for APC-dependent proteolysis in the budding yeast Saccharomyces cerevisiae. Here, we have investigated the cell cycle regulation of Cdc20 and Cdh1/Hct1. Whereas the levels CDH1/HCT1 RNA and Cdh1/Hct1 protein are constant throughout the cell cycle, CDC20 RNA and Cdc20 protein are present only during late S phase and mitosis and Cdc20 protein is unstable throughout the entire cell cycle. The instability of Cdc20 depends on CDC23 and CDC27, which encode components of the APC. During the G1 phase, a destruction box within Cdc20 mediates its instability, but during S phase and mitosis, although Cdc20 destruction is still dependent on CDC23 and CDC27, it does not depend on the Cdc20 destruction box. There are remarkable differences in the regulation of Cdc20 and Cdh1/Hct1. Furthermore, the APC activator Cdc20 is itself a substrate of the Cdc27 have a role in the degradation of Cdc20 during S Phase and early mitosis that is not mediated by its destruction box.

  1. Sipuleucel-T (APC8015) for prostate cancer.

    PubMed

    So-Rosillo, Rosendo; Small, Eric J

    2006-09-01

    Sipuleucel-T (Provenge; APC8015; Dendreon Corp, WA, USA) is a novel immunotherapeutic cellular product, which includes autologous dendritic cells pulsed ex vivo with a recombinant fusion protein (PA2024) consisting of granulocyte macrophage colony-stimulating factor and prostatic acid phosphatase. Two Phase II trials in men with androgen-dependent biochemically relapsed prostate cancer have demonstrated a decrease in prostate-specific antigen and prolongation in prostate-specific antigen doubling time. In men with hormone-refractory prostate cancer, clinical trials have demonstrated both biological activity and clinical response to sipuleucel-T. Data from two Phase III trials in men with asymptomatic, metastatic hormone-refractory prostate cancer demonstrated an improved median overall survival in men who received sipuleucel-T compared with placebo. Clinical trials are ongoing or are being developed to evaluate sipuleucel-T in various prostate cancer disease states and in combination with other treatment modalities.

  2. Wip1 abrogation decreases intestinal tumor frequency in APC(Min/+) mice irrespective of radiation quality.

    PubMed

    Suman, Shubhankar; Moon, Bo-Hyun; Thakor, Hemang; Fornace, Albert J; Datta, Kamal

    2014-09-01

    Low-linear energy transfer (low-LET) γ-ray exposure is a risk factor for colorectal cancer (CRC). Due to their high-LET nature, energetic iron ions found in space are expected to pose greater CRC risks to astronauts undertaking long-duration space missions beyond low Earth orbit. Wild-type p53-induced phosphatase 1 (Wip1) is important for cellular DNA damage response and its abrogation has been shown to inhibit spontaneous intestinal tumorigenesis in APC(Min/+) mice, a well-studied mouse model of human CRC. However, the relationship of Wip1 to radiation-induced intestinal tumorigenesis, especially by energetic iron ions, has not been investigated in APC(Min/+) mice. We have previously reported that there is a greater intestinal tumorigenic potential of iron-ion radiation relative to (137)Cs γ rays, so the purpose of the current study was to investigate whether Wip1 abrogation could influence high-LET dependent intestinal tumorigenesis in APC(Min/+) mice. Intestinal tumor frequency and grade were assessed in APC(Min/+)/Wip1(-/-) mice and results were compared to those in APC(Min/+)/Wip1(+/+) mice after exposure to a mean absorbed dose of 2 Gy from (137)Cs γ rays or 1.6 Gy from 1 GeV/n iron ions. Cellular differentiation and proliferation were also assessed in the intestinal tumors of sham-irradiated and irradiated mice. Decreased tumor frequency and lower tumor grade were observed in APC(Min/+)/Wip1(-/-) relative to APC(Min/+)/Wip1(+/+) mice. Notably, a similar decrease (∼6-fold in both groups) in tumor number was observed in sham-irradiated and γ-irradiated APC(Min/+)/Wip1(-/-) relative to APC(Min/+)/Wip1(+/+) mice. However, tumorigenesis in the energetic iron-ion exposed group was reduced ∼8-fold in APC(Min/+)/Wip1(-/-) relative to APC(Min/+)/Wip1(+/+) mice. A significantly lower proliferation/differentiation index in tumors of iron-ion exposed APC(Min/+)/Wip1(-/-) relative to APC(Min/+)/Wip1(+/+) mice suggests that reduced proliferation and enhanced

  3. Viral receptor-binding site antibodies with diverse germline origins

    PubMed Central

    Schmidt, Aaron G.; Therkelsen, Matthew D.; Stewart, Shaun; Kepler, Thomas B.; Liao, Hua-Xin; Moody, M. Anthony; Haynes, Barton F.; Harrison, Stephen C.

    2015-01-01

    Vaccines for rapidly evolving pathogens will confer lasting immunity if they elicit antibodies recognizing conserved epitopes, such as a receptor-binding site (RBS). From characteristics of an influenza-virus RBS-directed antibody, we devised a signature motif to search for similar antibodies. We identified, from three vaccinees, over 100 candidates encoded by eleven different VH genes. Crystal structures show that antibodies in this class engage the hemagglutinin RBS and mimic binding of the receptor, sialic acid, by supplying a critical dipeptide on their projecting, heavy-chain third complementarity determining region. They share contacts with conserved, receptor-binding residues but contact different residues on the RBS periphery, limiting the likelihood of viral escape when several such antibodies are present. These data show that related modes of RBS recognition can arise from different germline origins and mature through diverse affinity maturation pathways. Immunogens focused on an RBS-directed response will thus have a broad range of B-cell targets. PMID:25959776

  4. Germline Chd8 haploinsufficiency alters brain development in mouse.

    PubMed

    Gompers, Andrea L; Su-Feher, Linda; Ellegood, Jacob; Copping, Nycole A; Riyadh, M Asrafuzzaman; Stradleigh, Tyler W; Pride, Michael C; Schaffler, Melanie D; Wade, A Ayanna; Catta-Preta, Rinaldo; Zdilar, Iva; Louis, Shreya; Kaushik, Gaurav; Mannion, Brandon J; Plajzer-Frick, Ingrid; Afzal, Veena; Visel, Axel; Pennacchio, Len A; Dickel, Diane E; Lerch, Jason P; Crawley, Jacqueline N; Zarbalis, Konstantinos S; Silverman, Jill L; Nord, Alex S

    2017-08-01

    The chromatin remodeling gene CHD8 represents a central node in neurodevelopmental gene networks implicated in autism. We examined the impact of germline heterozygous frameshift Chd8 mutation on neurodevelopment in mice. Chd8(+/del5) mice displayed normal social interactions with no repetitive behaviors but exhibited cognitive impairment correlated with increased regional brain volume, validating that phenotypes of Chd8(+/del5) mice overlap pathology reported in humans with CHD8 mutations. We applied network analysis to characterize neurodevelopmental gene expression, revealing widespread transcriptional changes in Chd8(+/del5) mice across pathways disrupted in neurodevelopmental disorders, including neurogenesis, synaptic processes and neuroimmune signaling. We identified a co-expression module with peak expression in early brain development featuring dysregulation of RNA processing, chromatin remodeling and cell-cycle genes enriched for promoter binding by Chd8, and we validated increased neuronal proliferation and developmental splicing perturbation in Chd8(+/del5) mice. This integrative analysis offers an initial picture of the consequences of Chd8 haploinsufficiency for brain development.

  5. Identification of novel SNPs by next-generation sequencing of the genomic region containing the APC gene in colorectal cancer patients in China.

    PubMed

    Cheng, Yin; Wang, Jun; Shao, Jiaofang; Chen, Qiyun; Mo, Fan; Ma, Liang; Han, Xu; Zhang, Jing; Chen, Chen; Zhang, Cixiong; Lin, Shuyong; Yu, Jiekai; Zheng, Shu; Lin, Sheng-Cai; Lin, Biaoyang

    2010-06-01

    We described an approach of identifying single nucleotide polymorphisms (SNPs) in complete genomic regions of key genes including promoters, exons, introns, and downstream sequences by combining long-range polymerase chain reaction (PCR) or NimbleGen sequence capture with next-generation sequencing. Using the adenomatous polyposis coli (APC) gene as an example, we identified 210 highly reliable SNPs by next-generation sequencing analysis program MAQ and Samtools, of which 69 were novel ones, in the 123-kb APC genomic region in 27 pair of colorectal cancers and normal adjacent tissues. We confirmed all of the eight randomly selected high-quality SNPs by allele-specific PCR, suggesting that our false discovery rate is negligible. We identified 11 SNPs in the exonic region, including one novel SNP that was not previously reported. Although 10 of them are synonymous, they were predicted to affect splicing by creating or removing exonic splicing enhancers or exonic splicing silencers. We also identified seven SNPs in the upstream region of the APC gene, three of which were only identified in the cancer tissues. Six of these upstream SNPs were predicted to affect transcription factor binding. We also observed that long-range PCR was better in capturing GC-rich regions than the NimbleGen sequence capture technique.

  6. Mechanistic study of the anti-cancer effect of Gynostemma pentaphyllum saponins in the Apc(Min/+) mouse model.

    PubMed

    Tai, William Chi-Shing; Wong, Wing-Yan; Lee, Magnolia Muk-Lan; Chan, Brandon Dow; Lu, Cheng; Hsiao, Wen-Luan Wendy

    2016-05-01

    Gynostemma pentaphyllum saponins (GpS) have been shown to have anti-cancer activity. However, the underlying mechanisms remain unclear. In this study, we used the Apc(Min) (/+) colorectal cancer (CRC) mouse model to investigate the anti-cancer effect of GpS and we demonstrated that GpS treatment could significantly reduce the number and size of intestinal polyps in Apc(Min) (/+) mice. In order to identify the potential targets and mechanisms involved, a comparative proteomics analysis was performed and 40 differentially expressed proteins after GpS treatment were identified. Bioinformatics analyses suggested a majority of these proteins were involved in processes related to cellular redox homeostasis, and predicted Raf-1 as a potential target of GpS. The upregulation of two proteins known to be involved in redox homeostasis, peroxiredoxin-1 (Prdx1) and peroxiredoxin-2 (Prdx2), and the downregulation of Raf-1 were validated using Western blot analysis. After further investigation of the associated signaling networks, we postulated that the anti-cancer effect of GpS was mediated through the upregulation of Prdx1 and Prdx2, suppression of Ras, RAF/MEK/ERK/STAT, PI3K/AKT/mTOR signaling and modulation of JNK/p38 MAPK signaling. We also examined the potential combinatorial effect of GpS with the chemotherapeutic 5-fluorouracil (5-FU) and found that GpS could enhance the anti-cancer efficacy of 5-FU, further suppressing the number of polyps in Apc(Min/+) mice. Our findings highlight the potential of GpS as an anti-cancer agent, the potential mechanisms of its anti-cancer activities, and its effect as an adjuvant of 5-FU in the chemotherapy of CRC. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Impact of germline and somatic missense variations on drug binding sites.

    PubMed

    Yan, C; Pattabiraman, N; Goecks, J; Lam, P; Nayak, A; Pan, Y; Torcivia-Rodriguez, J; Voskanian, A; Wan, Q; Mazumder, R

    2017-03-01

    Advancements in next-generation sequencing (NGS) technologies are generating a vast amount of data. This exacerbates the current challenge of translating NGS data into actionable clinical interpretations. We have comprehensively combined germline and somatic nonsynonymous single-nucleotide variations (nsSNVs) that affect drug binding sites in order to investigate their prevalence. The integrated data thus generated in conjunction with exome or whole-genome sequencing can be used to identify patients who may not respond to a specific drug because of alterations in drug binding efficacy due to nsSNVs in the target protein's gene. To identify the nsSNVs that may affect drug binding, protein-drug complex structures were retrieved from Protein Data Bank (PDB) followed by identification of amino acids in the protein-drug binding sites using an occluded surface method. Then, the germline and somatic mutations were mapped to these amino acids to identify which of these alter protein-drug binding sites. Using this method we identified 12 993 amino acid-drug binding sites across 253 unique proteins bound to 235 unique drugs. The integration of amino acid-drug binding sites data with both germline and somatic nsSNVs data sets revealed 3133 nsSNVs affecting amino acid-drug binding sites. In addition, a comprehensive drug target discovery was conducted based on protein structure similarity and conservation of amino acid-drug binding sites. Using this method, 81 paralogs were identified that could serve as alternative drug targets. In addition, non-human mammalian proteins bound to drugs were used to identify 142 homologs in humans that can potentially bind to drugs. In the current protein-drug pairs that contain somatic mutations within their binding site, we identified 85 proteins with significant differential gene expression changes associated with specific cancer types. Information on protein-drug binding predicted drug target proteins and prevalence of both somatic and

  8. Lack of GNAQ and GNA11 Germ-Line Mutations in Familial Melanoma Pedigrees with Uveal Melanoma or Blue Nevi

    PubMed Central

    Hawkes, Jason E.; Campbell, Jennifer; Garvin, Daniel; Cannon-Albright, Lisa; Cassidy, Pamela; Leachman, Sancy A.

    2013-01-01

    Approximately 10% of melanoma cases are familial, but only 25–40% of familial melanoma cases can be attributed to germ-line mutations in the CDKN2A – the most significant high-risk melanoma susceptibility locus identified to date. The pathogenic mutation(s) in most of the remaining familial melanoma pedigrees have not yet been identified. The most common mutations in nevi and sporadic melanoma are found in BRAF and NRAS, both of which result in constitutive activation of the MAPK pathway. However, these mutations are not found in uveal melanomas or the intradermal melanocytic proliferations known as blue nevi. Rather, multiple studies report a strong association between these lesions and somatic mutations in Guanine nucleotide-binding protein G(q) subunit alpha (GNAQ), Guanine nucleotide-binding protein G(q) subunit alpha-11 (GNA11), and BRCA1-associated protein-1 (BAP1). Recently, germ-line mutations in BAP1, the gene encoding a tumor suppressing deubiquitinating enzyme, have been associated with predisposition to a variety of cancers including uveal melanoma, but no studies have examined the association of germ-line mutations in GNAQ and GNA11 with uveal melanoma and blue nevi. We have now done so by sequencing exon 5 of both of these genes in 13 unique familial melanoma pedigrees, members of which have had either uveal or cutaneous melanoma and/or blue nevi. Germ-line DNA from a total of 22 individuals was used for sequencing; however no deleterious mutations were detected. Nevertheless, such candidate gene studies and the discovery of novel germ-line mutations associated with an increased MM susceptibility can lead to a better understanding of the pathways involved in melanocyte transformation, formulation of risk assessment, and the development of specific drug therapies. PMID:23825798

  9. Lack of GNAQ and GNA11 Germ-Line Mutations in Familial Melanoma Pedigrees with Uveal Melanoma or Blue Nevi.

    PubMed

    Hawkes, Jason E; Campbell, Jennifer; Garvin, Daniel; Cannon-Albright, Lisa; Cassidy, Pamela; Leachman, Sancy A

    2013-01-01

    Approximately 10% of melanoma cases are familial, but only 25-40% of familial melanoma cases can be attributed to germ-line mutations in the CDKN2A - the most significant high-risk melanoma susceptibility locus identified to date. The pathogenic mutation(s) in most of the remaining familial melanoma pedigrees have not yet been identified. The most common mutations in nevi and sporadic melanoma are found in BRAF and NRAS, both of which result in constitutive activation of the MAPK pathway. However, these mutations are not found in uveal melanomas or the intradermal melanocytic proliferations known as blue nevi. Rather, multiple studies report a strong association between these lesions and somatic mutations in Guanine nucleotide-binding protein G(q) subunit alpha (GNAQ), Guanine nucleotide-binding protein G(q) subunit alpha-11 (GNA11), and BRCA1-associated protein-1 (BAP1). Recently, germ-line mutations in BAP1, the gene encoding a tumor suppressing deubiquitinating enzyme, have been associated with predisposition to a variety of cancers including uveal melanoma, but no studies have examined the association of germ-line mutations in GNAQ and GNA11 with uveal melanoma and blue nevi. We have now done so by sequencing exon 5 of both of these genes in 13 unique familial melanoma pedigrees, members of which have had either uveal or cutaneous melanoma and/or blue nevi. Germ-line DNA from a total of 22 individuals was used for sequencing; however no deleterious mutations were detected. Nevertheless, such candidate gene studies and the discovery of novel germ-line mutations associated with an increased MM susceptibility can lead to a better understanding of the pathways involved in melanocyte transformation, formulation of risk assessment, and the development of specific drug therapies.

  10. Epithelial-derived IL-33 promotes intestinal tumorigenesis in Apc (Min/+) mice.

    PubMed

    He, Zhengxiang; Chen, Lili; Souto, Fabricio O; Canasto-Chibuque, Claudia; Bongers, Gerold; Deshpande, Madhura; Harpaz, Noam; Ko, Huaibin M; Kelley, Kevin; Furtado, Glaucia C; Lira, Sergio A

    2017-07-14

    Increased expression of Interleukin (IL)-33 has been detected in intestinal samples of patients with ulcerative colitis, a condition associated with increased risk for colon cancer, but its role in the development of colorectal cancer has yet to be fully examined. Here, we investigated the role of epithelial expressed IL-33 during development of intestinal tumors. IL-33 expression was detected in epithelial cells in colorectal cancer specimens and in the Apc (Min/+) mice. To better understand the role of epithelial-derived IL-33 in the intestinal tumorigenesis, we generated transgenic mice expressing IL-33 in intestinal epithelial cells (V33 mice). V33 Apc (Min/+) mice, resulting from the cross of V33 with Apc (Min/+) mice, had increased intestinal tumor burden compared with littermate Apc (Min/+) mice. Consistently, Apc (Min/+) mice deficient for IL-33 receptor (ST2), had reduced polyp burden. Mechanistically, overexpression of IL-33 promoted expansion of ST2(+) regulatory T cells, increased Th2 cytokine milieu, and induced alternatively activated macrophages in the gut. IL-33 promoted marked changes in the expression of antimicrobial peptides, and antibiotic treatment of V33 Apc (Min/+) mice abrogated the tumor promoting-effects of IL-33 in the colon. In conclusion, elevated IL-33 signaling increases tumor development in the Apc (Min/+) mice.

  11. Apc-Mutant Kyoto Apc Delta (KAD) Rats Are Susceptible to 4-NQO-Induced Tongue Carcinogenesis

    PubMed Central

    Tanaka, Takuji; Shimizu, Masahito; Kochi, Takahiro; Shirakami, Yohei; Mori, Takayuki; Watanabe, Naoki; Naiki, Takafumi; Moriwaki, Hisataka; Yoshimi, Kazuto; Serikawa, Tadao; Kuramoto, Takashi

    2014-01-01

    Despite widening interest in the possible association between infection/inflammation and cancer development, knowledge of this issue in relation to oral cancer remains inadequate. This study aimed to determine the susceptibility of Apc-mutant Kyoto Apc Delta (KAD) rats, which are vulnerable to developing inflammation-associated colorectal carcinogenesis, to 4-nitroquinoline 1-oxide (4-NQO)-induced tongue carcinogenesis in order to clarify the role of inflammation in oral cancer. KAD (20 males and 22 females) and F344/NS1c (22 males and 23 females) rats received drinking water with or without 4-NQO (20 ppm) for eight weeks. Histopathological and immunohistochemical analyses of the tongue were performed at week 20. Additionally, the mRNA expression of inflammatory cytokines in the tongue mucosa was determined at week 8. Tongue squamous cell carcinoma (SCC) developed in the KAD and F344/NS1c rats that received 4-NQO. Regardless of gender, the incidence and multiplicity of tongue SCC were greater in the KAD rats than in the F344/NS1c rats. In addition, the multiplicity of tongue SCC in the female KAD rats was significantly greater than that observed in the male KAD (p < 0.01) and female F344/NS1c rats (p < 0.05). The levels of inflammation and the mRNA expression of inflammatory cytokines in the tongue in the 4-NQO-treated female KAD rats were the highest among the rats given 4-NQO. These results show that KAD rats, particularly females, are susceptible to 4-NQO-induced tongue carcinogenesis, suggesting the utility of models employing KAD rats for investigating the pathobiology of oral (tongue) carcinogenesis associated with inflammation. PMID:25050571

  12. Kaiso overexpression promotes intestinal inflammation and potentiates intestinal tumorigenesis in Apc(Min/+) mice.

    PubMed

    Pierre, Christina C; Longo, Joseph; Mavor, Meaghan; Milosavljevic, Snezana B; Chaudhary, Roopali; Gilbreath, Ebony; Yates, Clayton; Daniel, Juliet M

    2015-09-01

    Constitutive Wnt/β-catenin signaling is a key contributor to colorectal cancer (CRC). Although inactivation of the tumor suppressor adenomatous polyposis coli (APC) is recognized as an early event in CRC development, it is the accumulation of multiple subsequent oncogenic insults facilitates malignant transformation. One potential contributor to colorectal carcinogenesis is the POZ-ZF transcription factor Kaiso, whose depletion extends lifespan and delays polyp onset in the widely used Apc(Min/+) mouse model of intestinal cancer. These findings suggested that Kaiso potentiates intestinal tumorigenesis, but this was paradoxical as Kaiso was previously implicated as a negative regulator of Wnt/β-catenin signaling. To resolve Kaiso's role in intestinal tumorigenesis and canonical Wnt signaling, we generated a transgenic mouse model (Kaiso(Tg/+)) expressing an intestinal-specific myc-tagged Kaiso transgene. We then mated Kaiso(Tg/+) and Apc(Min/+) mice to generate Kaiso(Tg/+):Apc(Min/+) mice for further characterization. Kaiso(Tg/+):Apc(Min/+) mice exhibited reduced lifespan and increased polyp multiplicity compared to Apc(Min/+) mice. Consistent with this murine phenotype, we found increased Kaiso expression in human CRC tissue, supporting a role for Kaiso in human CRC. Interestingly, Wnt target gene expression was increased in Kaiso(Tg/+):Apc(Min/+) mice, suggesting that Kaiso's function as a negative regulator of canonical Wnt signaling, as seen in Xenopus, is not maintained in this context. Notably, Kaiso(Tg/+):Apc(Min/+) mice exhibited increased inflammation and activation of NFκB signaling compared to their Apc(Min/+) counterparts. This phenotype was consistent with our previous report that Kaiso(Tg/+) mice exhibit chronic intestinal inflammation. Together our findings highlight a role for Kaiso in promoting Wnt signaling, inflammation and tumorigenesis in the mammalian intestine. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Use of Germline Polymorphisms in Predicting Concurrent Chemoradiotherapy Response in Esophageal Cancer

    SciTech Connect

    Chen, Pei-Chun; Chen, Yen-Ching; Lai, Liang-Chuan; Tsai, Mong-Hsun; Chen, Shin-Kuang; Yang, Pei-Wen; Lee, Yung-Chie; Hsiao, Chuhsing K.; Lee, Jang-Ming; Chuang, Eric Y.

    2012-04-01

    Purpose: To identify germline polymorphisms to predict concurrent chemoradiation therapy (CCRT) response in esophageal cancer patients. Materials and Methods: A total of 139 esophageal cancer patients treated with CCRT (cisplatin-based chemotherapy combined with 40 Gy of irradiation) and subsequent esophagectomy were recruited at the National Taiwan University Hospital between 1997 and 2008. After excluding confounding factors (i.e., females and patients aged {>=}70 years), 116 patients were enrolled to identify single nucleotide polymorphisms (SNPs) associated with specific CCRT responses. Genotyping arrays and mass spectrometry were used sequentially to determine germline polymorphisms from blood samples. These polymorphisms remain stable throughout disease progression, unlike somatic mutations from tumor tissues. Two-stage design and additive genetic models were adopted in this study. Results: From the 26 SNPs identified in the first stage, 2 SNPs were found to be significantly associated with CCRT response in the second stage. Single nucleotide polymorphism rs16863886, located between SGPP2 and FARSB on chromosome 2q36.1, was significantly associated with a 3.93-fold increase in pathologic complete response to CCRT (95% confidence interval 1.62-10.30) under additive models. Single nucleotide polymorphism rs4954256, located in ZRANB3 on chromosome 2q21.3, was associated with a 3.93-fold increase in pathologic complete response to CCRT (95% confidence interval 1.57-10.87). The predictive accuracy for CCRT response was 71.59% with these two SNPs combined. Conclusions: This is the first study to identify germline polymorphisms with a high accuracy for predicting CCRT response in the treatment of esophageal cancer.

  14. Two Classes of Gap Junction Channels Mediate Soma-Germline Interactions Essential for Germline Proliferation and Gametogenesis in Caenorhabditis elegans

    PubMed Central

    Starich, Todd A.; Hall, David H.; Greenstein, David

    2014-01-01

    In all animals examined, somatic cells of the gonad control multiple biological processes essential for germline development. Gap junction channels, composed of connexins in vertebrates and innexins in invertebrates, permit direct intercellular communication between cells and frequently form between somatic gonadal cells and germ cells. Gap junctions comprise hexameric hemichannels in apposing cells that dock to form channels for the exchange of small molecules. Here we report essential roles for two classes of gap junction channels, composed of five innexin proteins, in supporting the proliferation of germline stem cells and gametogenesis in the nematode Caenorhabditis elegans. Transmission electron microscopy of freeze-fracture replicas and fluorescence microscopy show that gap junctions between somatic cells and germ cells are more extensive than previously appreciated and are found throughout the gonad. One class of gap junctions, composed of INX-8 and INX-9 in the soma and INX-14 and INX-21 in the germ line, is required for the proliferation and differentiation of germline stem cells. Genetic epistasis experiments establish a role for these gap junction channels in germline proliferation independent of the glp-1/Notch pathway. A second class of gap junctions, composed of somatic INX-8 and INX-9 and germline INX-14 and INX-22, is required for the negative regulation of oocyte meiotic maturation. Rescue of gap junction channel formation in the stem cell niche rescues germline proliferation and uncovers a later channel requirement for embryonic viability. This analysis reveals gap junctions as a central organizing feature of many soma–germline interactions in C. elegans. PMID:25195067

  15. Germline mutations predisposing to diffuse large B-cell lymphoma

    PubMed Central

    Leeksma, O C; de Miranda, N F; Veelken, H

    2017-01-01

    Genetic studies of diffuse large B-cell lymphomas (DLBCLs) in humans have revealed numerous targets of somatic mutations and an increasing number of potentially relevant germline alterations. The latter often affect genes involved in DNA repair and/or immune function. In general, defects in these genes also predispose to other conditions. Knowledge of these mutations can lead to disease-preventing measures in the patient and relatives thereof. Conceivably, these germline mutations will be taken into account in future therapy of the lymphoma. In other hematological malignancies, mutations originally found as somatic aberrations have also been shown to confer predisposition to these diseases, when occurring in the germline. Further interrogations of the genome in DLBCL patients are therefore expected to reveal additional hereditary predisposition genes. Our review shows that germline mutations have already been described in over one-third of the genes that are somatically mutated in DLBCL. Whether such germline mutations predispose carriers to DLBCL is an open question. Symptoms of the inherited syndromes associated with these genes range from anatomical malformations to intellectual disability, immunodeficiencies and malignancies other than DLBCL. Inherited or de novo alterations in protein-coding and non-coding genes are envisioned to underlie this lymphoma. PMID:28211887

  16. Germline TP53 mutations and single nucleotide polymorphisms in children.

    PubMed

    Valva, Pamela; Becker, Pablo; Streitemberger, Patricia; Lombardi, García Mercedes; Rey, Guadalupe; Guzman, Carlos A; Preciado, María Victoria

    2009-01-01

    Mutations in the gene TP53, which codifies the tumor suppressor protein p53, are found in about 50% of tumors. These mutations can occur not only at somatic level, but also in germline. Pediatric cancer patients, mostly with additional family history of malignancy, should be considered as potential TP53 germline mutation carriers. Germline TP53 mutations and polymorphisms have been widely studied to determine their relation with different tumors' pathogenesis. Our aim was to analyze the occurrence frequency of germline TP53 mutations and polymorphisms and to relate these to tumor development in a pediatric series. Peripheral blood mononuclear cell samples from 26 children with solid tumors [PST] and 21 pediatric healthy donors [HD] were analyzed for germline mutations and polymorphisms in TP53 gene spanning from exon 5 to 8 including introns 5 and 7. These PCR amplified fragments were sequenced to determine variations. A heterozygous mutation at codon 245 was found in 1/26 PST and 0/21 HD. Comparative polymorphisms distribution, at position 14181 and 14201(intron 7), between HD and PST revealed a trend of association (p= 0.07) with cancer risk. HD group disclosed a similar polymorphism distribution as published data for Caucasian and Central/South American populations. This is the first study about TP53 variant frequency and distribution in healthy individuals and cancer patients in Argentina.

  17. Genotype and phenotype spectrum of NRAS germline variants.

    PubMed

    Altmüller, Franziska; Lissewski, Christina; Bertola, Debora; Flex, Elisabetta; Stark, Zornitza; Spranger, Stephanie; Baynam, Gareth; Buscarilli, Michelle; Dyack, Sarah; Gillis, Jane; Yntema, Helger G; Pantaleoni, Francesca; van Loon, Rosa LE; MacKay, Sara; Mina, Kym; Schanze, Ina; Tan, Tiong Yang; Walsh, Maie; White, Susan M; Niewisch, Marena R; García-Miñaúr, Sixto; Plaza, Diego; Ahmadian, Mohammad Reza; Cavé, Hélène; Tartaglia, Marco; Zenker, Martin

    2017-06-01

    RASopathies comprise a group of disorders clinically characterized by short stature, heart defects, facial dysmorphism, and varying degrees of intellectual disability and cancer predisposition. They are caused by germline variants in genes encoding key components or modulators of the highly conserved RAS-MAPK signalling pathway that lead to dysregulation of cell signal transmission. Germline changes in the genes encoding members of the RAS subfamily of GTPases are rare and associated with variable phenotypes of the RASopathy spectrum, ranging from Costello syndrome (HRAS variants) to Noonan and Cardiofaciocutaneous syndromes (KRAS variants). A small number of RASopathy cases with disease-causing germline NRAS alterations have been reported. Affected individuals exhibited features fitting Noonan syndrome, and the observed germline variants differed from the typical oncogenic NRAS changes occurring as somatic events in tumours. Here we describe 19 new cases with RASopathy due to disease-causing variants in NRAS. Importantly, four of them harbored missense changes affecting Gly12, which was previously described to occur exclusively in cancer. The phenotype in our cohort was variable but well within the RASopathy spectrum. Further, one of the patients (c.35G>A; p.(Gly12Asp)) had a myeloproliferative disorder, and one subject (c.34G>C; p.(Gly12Arg)) exhibited an uncharacterized brain tumour. With this report, we expand the genotype and phenotype spectrum of RASopathy-associated germline NRAS variants and provide evidence that NRAS variants do not spare the cancer-associated mutation hotspots.

  18. Inference on germline BAP1 mutations and asbestos exposure from the analysis of familial and sporadic mesothelioma in a high-risk area.

    PubMed

    Betti, Marta; Casalone, Elisabetta; Ferrante, Daniela; Romanelli, Antonio; Grosso, Federica; Guarrera, Simonetta; Righi, Luisella; Vatrano, Simona; Pelosi, Giuseppe; Libener, Roberta; Mirabelli, Dario; Boldorini, Renzo; Casadio, Caterina; Papotti, Mauro; Matullo, Giuseppe; Magnani, Corrado; Dianzani, Irma

    2015-01-01

    Inherited loss-of-function mutations in the BAP1 oncosuppressor gene are responsible for an inherited syndrome with predisposition to malignant mesothelioma (MM), uveal and keratinocytic melanoma, and other malignancies. Germline mutations that were inherited in an autosomal dominant fashion were identified in nine families with multiplex MM cases and 25 families with multiple melanoma, renal cell carcinoma, and other tumors. Germline mutations were also identified in sporadic MM cases, suggesting that germline mutations in BAP1 occur frequently. In this article, we report the analysis of BAP1 in five multiplex MM families and in 103 sporadic cases of MM. One family carried a new truncating germline mutation. Using immunohistochemistry, we show that BAP1 is not expressed in tumor tissue, which is in accordance with Knudson's two hits hypothesis. Interestingly, whereas the three individuals who were possibly exposed to asbestos developed MM, the individual who was not exposed developed a different tumor type, that is, mucoepidermoid carcinoma. This finding suggests that the type of carcinogen exposure may be important for the cancer type that is developed by mutation carriers. On the contrary, the other families or the 103 sporadic patients did not show germline mutations in BAP1. Our data show that BAP1 mutations are very rare in patients with sporadic MM, and we report a new BAP1 mutation, extend the cancer types associated with these mutations, and suggest the existence of other yet unknown genes in the pathogenesis of familial MM.

  19. Adenomatous polyposis coli (APC) regulates multiple signaling pathways by enhancing glycogen synthase kinase-3 (GSK-3) activity.

    PubMed

    Valvezan, Alexander J; Zhang, Fang; Diehl, J Alan; Klein, Peter S

    2012-02-03

    Glycogen synthase kinase-3 (GSK-3) is essential for many signaling pathways and cellular processes. As Adenomatous Polyposis Coli (APC) functions in many of the same processes, we investigated a role for APC in the regulation of GSK-3-dependent signaling. We find that APC directly enhances GSK-3 activity. Furthermore, knockdown of APC mimics inhibition of GSK-3 by reducing phosphorylation of glycogen synthase and by activating mTOR, revealing novel roles for APC in the regulation of these enzymes. Wnt signaling inhibits GSK-3 through an unknown mechanism, and this results in both stabilization of β-catenin and activation of mTOR. We therefore hypothesized that Wnts may regulate GSK-3 by disrupting the interaction between APC and the Axin-GSK-3 complex. We find that Wnts rapidly induce APC dissociation from Axin, correlating with β-catenin stabilization. Furthermore, Axin interaction with the Wnt co-receptor LRP6 causes APC dissociation from Axin. We propose that APC regulates multiple signaling pathways by enhancing GSK-3 activity, and that Wnts induce APC dissociation from Axin to reduce GSK-3 activity and activate downstream signaling. APC regulation of GSK-3 also provides a novel mechanism for Wnt regulation of multiple downstream effectors, including β-catenin and mTOR.

  20. Comprehensive analysis of BRCA1, BRCA2 and TP53 germline mutation and tumor characterization: a portrait of early-onset breast cancer in Brazil.

    PubMed

    Carraro, Dirce Maria; Koike Folgueira, Maria Aparecida Azevedo; Garcia Lisboa, Bianca Cristina; Ribeiro Olivieri, Eloisa Helena; Vitorino Krepischi, Ana Cristina; de Carvalho, Alex Fiorini; de Carvalho Mota, Louise Danielle; Puga, Renato David; do Socorro Maciel, Maria; Michelli, Rodrigo Augusto Depieri; de Lyra, Eduardo Carneiro; Grosso, Stana Helena Giorgi; Soares, Fernando Augusto; Achatz, Maria Isabel Alves de Souza Waddington; Brentani, Helena; Moreira-Filho, Carlos Alberto; Brentani, Maria Mitzi

    2013-01-01

    Germline mutations in BRCA1, BRCA2 and TP53 genes have been identified as one of the most important disease-causing issues in young breast cancer patients worldwide. The specific defective biological processes that trigger germline mutation-associated and -negative tumors remain unclear. To delineate an initial portrait of Brazilian early-onset breast cancer, we performed an investigation combining both germline and tumor analysis. Germline screening of the BRCA1, BRCA2, CHEK2 (c.1100delC) and TP53 genes was performed in 54 unrelated patients <35 y; their tumors were investigated with respect to transcriptional and genomic profiles as well as hormonal receptors and HER2 expression/amplification. Germline mutations were detected in 12 out of 54 patients (22%) [7 in BRCA1 (13%), 4 in BRCA2 (7%) and one in TP53 (2%) gene]. A cancer familial history was present in 31.4% of the unrelated patients, from them 43.7% were carriers for germline mutation (37.5% in BRCA1 and in 6.2% in the BRCA2 genes). Fifty percent of the unrelated patients with hormone receptor-negative tumors carried BRCA1 mutations, percentage increasing to 83% in cases with familial history of cancer. Over-representation of DNA damage-, cellular and cell cycle-related processes was detected in the up-regulated genes of BRCA1/2-associated tumors, whereas cell and embryo development-related processes were over-represented in the up-regulated genes of BRCA1/2-negative tumors, suggesting distinct mechanisms driving the tumorigenesis. An initial portrait of the early-onset breast cancer patients in Brazil was generated pointing out that hormone receptor-negative tumors and positive familial history are two major risk factors for detection of a BRCA1 germline mutation. Additionally, the data revealed molecular factors that potentially trigger the tumor development in young patients.

  1. Germline and somatic mutations in cyclin-dependent kinase inhibitor genes CDKN1A, CDKN2B, and CDKN2C in sporadic parathyroid adenomas.

    PubMed

    Costa-Guda, Jessica; Soong, Chen-Pang; Parekh, Vaishali I; Agarwal, Sunita K; Arnold, Andrew

    2013-10-01

    The molecular pathogenesis of sporadic parathyroid adenomas is incompletely understood. The possible role of cyclin-dependent kinase inhibitor (CDKI) genes was raised by recognition of cyclin D1 as a parathyroid oncogene, identification of rare germline mutations in CDKI genes in patients with multiple endocrine neoplasia type 1; that in rodents, mutation in Cdkn1b caused parathyroid tumors; and subsequently through identification of rare predisposing germline sequence variants and somatic mutation of CDKN1B, encoding p27(kip1), in sporadic human parathyroid adenoma. We therefore sought to determine whether mutations/variants in the other six CDKI genes CDKN1A, CDKN1C, CDKN2A, CDKN2B, CDKN2C, and CDKN2D, encoding p21, p57, p14(ARF)/p16, p15, p18, and p19, respectively, contribute to the development of typical parathyroid adenomas. In a series of 85 sporadic parathyroid adenomas, direct DNA sequencing identified alterations in five adenomas (6 %): Two contained distinct heterozygous changes in CDKN1A, one germline and one of undetermined germline status; one had a CDKN2B germline alteration, accompanied by loss of the normal allele in the tumor (LOH); two had variants of CDKN2C, one somatic and one germline with LOH. Abnormalities of three of the mutant proteins were readily demonstrable in vitro. Thus, germline mutations/rare variants in CDKN1A, CDKN2B, and CDKN2C likely contribute to the development of a significant subgroup of common sporadic parathyroid adenomas, and somatic mutation in CDKN2C further suggests a direct role for CDKI alteration in conferring a selective growth advantage to parathyroid cells, providing novel support for the concept that multiple CDKIs can play primary roles in human neoplasia.

  2. Identification of Regions Interacting with Ovo(d) Mutations: Potential New Genes Involved in Germline Sex Determination or Differentiation in Drosophila Melanogaster

    PubMed Central

    Pauli, D.; Oliver, B.; Mahowald, A. P.

    1995-01-01

    Only a few Drosophila melanogaster germline sex determination genes are known, and there have been no systematic screens to identify new genes involved in this important biological process. The ovarian phenotypes produced by females mutant for dominant alleles of the ovo gene are modified in flies with altered doses of other loci involved in germline sex determination in Drosophila (Sex-lethal(+), sans fille(+) and ovarian tumor(+)). This observation constitutes the basis for a screen to identify additional genes required for proper establishment of germline sexual identity. We tested 300 deletions, which together cover ~58% of the euchromatic portion of the genome, for genetic interactions with ovo(D). Hemizygosity for more than a dozen small regions show interactions that either partially suppress or enhance the ovarian phenotypes of females mutant for one or more of the three dominant ovo mutations. These regions probably contain genes whose products act in developmental hierarchies that include ovo(+) protein. PMID:7713427

  3. Open-ended question: is immortality exclusively inherent to the germline?--A mini-review.

    PubMed

    Lepperdinger, Günter

    2009-01-01

    All somatic cells are subject to aging. Germline links generations, and thus, pluripotent germ cells are considered potentially immortal. The current understanding how the germline escapes this otherwise inevitable phenomenon is outlined in this article.

  4. Morphological predictors of BRCA1 germline mutations in young women with breast cancer.

    PubMed

    Southey, M C; Ramus, S J; Dowty, J G; Smith, L D; Tesoriero, A A; Wong, E E M; Dite, G S; Jenkins, M A; Byrnes, G B; Winship, I; Phillips, K-A; Giles, G G; Hopper, J L

    2011-03-15

    Knowing a young woman with newly diagnosed breast cancer has a germline BRCA1 mutation informs her clinical management and that of her relatives. We sought an optimal strategy for identifying carriers using family history, breast cancer morphology and hormone receptor status data. We studied a population-based sample of 452 Australian women with invasive breast cancer diagnosed before age 40 years for whom we conducted extensive germline mutation testing (29 carried a BRCA1 mutation) and a systematic pathology review, and collected three-generational family history and tumour ER and PR status. Predictors of mutation status were identified using multiple logistic regression. Areas under receiver operator characteristic (ROC) curves were estimated using five-fold stratified cross-validation. The probability of being a BRCA1 mutation carrier increased with number of selected histology features even after adjusting for family history and ER and PR status (P<0.0001). From the most parsimonious multivariate model, the odds ratio for being a carrier were: 9.7 (95% confidence interval: 2.6-47.0) for trabecular growth pattern (P=0.001); 7.8 (2.7-25.7) for mitotic index over 50 mitoses per 10 high-powered field (P=0.0003); and 2.7 (1.3-5.9) for each first-degree relative with breast cancer diagnosed before age 60 years (P=0.01).The area under the ROC curve was 0.87 (0.83-0.90). Pathology review, with attention to a few specific morphological features of invasive breast cancers, can identify almost all BRCA1 germline mutation carriers among women with early-onset breast cancer without taking into account family history.

  5. Isolation of Undifferentiated Female Germline Cells from Adult Drosophila Ovaries.

    PubMed

    Lim, Robyn Su May; Osato, Motomi; Kai, Toshie

    2015-08-03

    This unit describes a method for isolating undifferentiated, stem cell-like germline cells from adult Drosophila ovaries. Here, we demonstrate that this population of cells can be effectively purified from hand-dissected ovaries in considerably large quantities. Tumor ovaries with expanded populations of undifferentiated germline cells are first removed from fly abdomens and dissociated into a cell suspension with the aid of protease treatment. The target cells, which express Vasa-green fluorescent protein (GFP) fusion protein under the control of the germline-specific vasa promoter, are specifically selected from the suspension via fluorescence-activated cell sorting (FACS). These protocols can be adapted to isolate other cell types from fly ovaries, such as somatic follicle cells or escort cells, by driving GFP expression in the respective target cells.

  6. Germline determinants of clinical outcome of cutaneous melanoma.

    PubMed

    Vogelsang, Matjaz; Wilson, Melissa; Kirchhoff, Tomas

    2016-01-01

    Cutaneous melanoma (CM) is the most lethal form of skin cancer. Despite the constant increase in melanoma incidence, which is in part due to incremental advances in early diagnostic modalities, mortality rates have not improved over the last decade and for advanced stages remain steadily high. While conventional prognostic biomarkers currently in use find significant utility for predicting overall general survival probabilities, they are not sensitive enough for a more personalized clinical assessment on an individual level. In recent years, the advent of genomic technologies has brought the promise of identification of germline DNA alterations that may associate with CM outcomes and hence represent novel biomarkers for clinical utilization. This review attempts to summarize the current state of knowledge of germline genetic factors studied for their impact on melanoma clinical outcomes. We also discuss ongoing problems and hurdles in validating such surrogates, and we also project future directions in discovery of more powerful germline genetic factors with clinical utility in melanoma prognostication.

  7. Potential Germline Competition in Animals and Its Evolutionary Implications

    PubMed Central

    Hastings, I. M.

    1989-01-01

    Mutation, mitotic crossing over and mitotic gene conversion can create genetic diversity in otherwise uniform diploid cell lineages. In the germline this diversification may result in competition between diploid germline phenotypes, with subsequent biases in the frequency of alleles transmitted to the offspring. Sperm competition is a well documented feature of many higher organisms and a model is developed to quantify this process. Competition, and hence selection, can also occur by differential survival of diploid lineages before meiosis. It is concluded that under certain circumstances germline selection is an efficient means of eliminating unfavorable alleles from the population. This does not require differences in adult fertility or viability which is the usual mechanism cited as causing changes in gene frequency in a population. It is proposed that such competition may play a role in maintaining the efficiency of basic metabolic pathways. PMID:2806882

  8. Reconciling views on T cell receptor germline bias for MHC.

    PubMed

    Garcia, K Christopher

    2012-09-01

    Whether MHC restriction by the T cell receptor (TCR) is a product of evolutionary pressures leading to germline-encoded 'rules of engagement' remains avidly debated. Structural results derived from analysis of TCR-peptide-MHC complexes appear to support a model of physical specificity between TCR germline V regions and MHC. Yet, some recent evidence suggests that thymic selection, and co-receptors may have misled us into thinking the TCR is exclusively MHC-specific, when in fact, TCRs can robustly engage non-MHC ligands when given the chance. Here, I propose that seemingly contradictory data and hypotheses for, and against, germline bias are, in fact, compatible and can be reconciled into a unifying model.

  9. A Patient with an Extra-adrenal Pheochromocytoma and Germ-line SDHB Mutation Accompanied by an Atypical Meningioma.

    PubMed

    Shiwa, Tsuguka; Oki, Kenji; Yoneda, Masayasu; Arihiro, Koji; Ohno, Haruya; Kishimoto, Rui; Kohno, Nobuoki

    2015-01-01

    The gene succinate dehydrogenase subunit B (SDHB) encodes a protein comprising part of the mitochondrial complex II, which links the Krebs cycle and the electron-transport chain. Heterozygous germ-line SDHB mutations causes familial pheochromocytoma-paraganglioma syndrome and has also been linked to gastrointestinal stromal tumors, as well as renal cell carcinomas. We herein report a patient with a germ-line SDHB mutation who presented with an atypical meningioma that was identified as originating from a somatic SDHB mutation. The 41-year-old man, who had a surgical history of extra-adrenal pheochromocytoma at 23 years of age, recently developed gait disorder and hypertension. At the radiological examination, a tumor was detected in the cervical spinal cord at the C6-7 intervertebral level. The pathological findings of the isolated tumor were atypical meningioma assessed as grade II according to the World Health Organization criteria. Inherited neoplasia syndrome was suspected because of the patient's history of early-onset extra-adrenal pheochromocytoma and the development of meningioma. We therefore performed molecular genetic analyses. A direct sequence analysis revealed a heterozygous germ-line frameshift mutation in SDHB, specifically an 11-nucleotide deletion, c.305-315delCAATGAACATC, in exon 4, resulting in a frameshift p.A102EfsX12. Additionally, the sequence analysis of the tumor DNA revealed only a mutated allele with a frameshift mutation in the germ-line SDHB. Our findings suggest that SDHB plays an important role in the pathogenesis of meningiomas as well as pheochromocytomas. Therefore, a differential diagnosis for metastatic pheochromocytoma and other new onset tumors, including meningioma, particularly in patients with germ-line SDHB mutations and a previous history of pheochromocytoma should be carefully made.

  10. Molecular characterization of MSI-H colorectal cancer by MLHI promoter methylation, immunohistochemistry, and mismatch repair germline mutation screening.

    PubMed

    Poynter, Jenny N; Siegmund, Kimberly D; Weisenberger, Daniel J; Long, Tiffany I; Thibodeau, Stephen N; Lindor, Noralane; Young, Joanne; Jenkins, Mark A; Hopper, John L; Baron, John A; Buchanan, Dan; Casey, Graham; Levine, A Joan; Le Marchand, Loïc; Gallinger, Steven; Bapat, Bharati; Potter, John D; Newcomb, Polly A; Haile, Robert W; Laird, Peter W

    2008-11-01

    Microsatellite instability (MSI) occurs in 10% to 20% of colorectal cancers (CRC) and has been attributed to both MLH1 promoter hypermethylation and germline mutation in the mismatch repair (MMR) genes. We present results from a large population- and clinic-based study of MLH1 methylation, immunohistochemistry, and MMR germline mutations that enabled us to (a) estimate the prevalence of MMR germline mutations and MLH1 methylation among MSI-H cases and help us understand if all MSI-H CRC is explained by these mechanisms and (b) estimate the associations between MLH1 methylation and sex, age, and tumor location within the colon. MLH1 methylation was measured in 1,061 population-based and 172 clinic-based cases of CRC. Overall, we observed MLH1 methylation in 60% of population-based MSI-H cases and in 13% of clinic-based MSI-H cases. Within the population-based cases with MMR mutation screening and conclusive immunohistochemistry results, we identified a molecular event in MMR in 91% of MSI-H cases: 54% had MLH1 methylation, 14% had a germline mutation in a MMR gene, and 23% had immunohistochemistry evidence for loss of a MMR protein. We observed a striking age difference, with the prevalence of a MMR germline mutation more than 4-fold lower and the prevalence of MLH1 methylation more than 4-fold higher in cases diagnosed after the age of 50 years than in cases diagnosed before that age. We also determined that female sex is an independent predictor of MLH1 methylation within the MSI-H subgroup. These results reinforce the importance of distinguishing between the underlying causes of MSI in studies of etiology and prognosis.

  11. Sex Chromosome-wide Transcriptional Suppression and Compensatory Cis-Regulatory Evolution Mediate Gene Expression in the Drosophila Male Germline

    PubMed Central

    Landeen, Emily L.; Muirhead, Christina A.; Meiklejohn, Colin D.; Presgraves, Daven C.

    2016-01-01

    The evolution of heteromorphic sex chromosomes has repeatedly resulted in the evolution of sex chromosome-specific forms of regulation, including sex chromosome dosage compensation in the soma and meiotic sex chromosome inactivation in the germline. In the male germline of Drosophila melanogaster, a novel but poorly understood form of sex chromosome-specific transcriptional regulation occurs that is distinct from canonical sex chromosome dosage compensation or meiotic inactivation. Previous work shows that expression of reporter genes driven by testis-specific promoters is considerably lower—approximately 3-fold or more—for transgenes inserted into X chromosome versus autosome locations. Here we characterize this transcriptional suppression of X-linked genes in the male germline and its evolutionary consequences. Using transgenes and transpositions, we show that most endogenous X-linked genes, not just testis-specific ones, are transcriptionally suppressed several-fold specifically in the Drosophila male germline. In wild-type testes, this sex chromosome-wide transcriptional suppression is generally undetectable, being effectively compensated by the gene-by-gene evolutionary recruitment of strong promoters on the X chromosome. We identify and experimentally validate a promoter element sequence motif that is enriched upstream of the transcription start sites of hundreds of testis-expressed genes; evolutionarily conserved across species; associated with strong gene expression levels in testes; and overrepresented on the X chromosome. These findings show that the expression of X-linked genes in the Drosophila testes reflects a balance between chromosome-wide epigenetic transcriptional suppression and long-term compensatory adaptation by sex-linked genes. Our results have broad implications for the evolution of gene expression in the Drosophila male germline and for genome evolution. PMID:27404402

  12. Sex Chromosome-wide Transcriptional Suppression and Compensatory Cis-Regulatory Evolution Mediate Gene Expression in the Drosophila Male Germline.

    PubMed

    Landeen, Emily L; Muirhead, Christina A; Wright, Lori; Meiklejohn, Colin D; Presgraves, Daven C

    2016-07-01

    The evolution of heteromorphic sex chromosomes has repeatedly resulted in the evolution of sex chromosome-specific forms of regulation, including sex chromosome dosage compensation in the soma and meiotic sex chromosome inactivation in the germline. In the male germline of Drosophila melanogaster, a novel but poorly understood form of sex chromosome-specific transcriptional regulation occurs that is distinct from canonical sex chromosome dosage compensation or meiotic inactivation. Previous work shows that expression of reporter genes driven by testis-specific promoters is considerably lower-approximately 3-fold or more-for transgenes inserted into X chromosome versus autosome locations. Here we characterize this transcriptional suppression of X-linked genes in the male germline and its evolutionary consequences. Using transgenes and transpositions, we show that most endogenous X-linked genes, not just testis-specific ones, are transcriptionally suppressed several-fold specifically in the Drosophila male germline. In wild-type testes, this sex chromosome-wide transcriptional suppression is generally undetectable, being effectively compensated by the gene-by-gene evolutionary recruitment of strong promoters on the X chromosome. We identify and experimentally validate a promoter element sequence motif that is enriched upstream of the transcription start sites of hundreds of testis-expressed genes; evolutionarily conserved across species; associated with strong gene expression levels in testes; and overrepresented on the X chromosome. These findings show that the expression of X-linked genes in the Drosophila testes reflects a balance between chromosome-wide epigenetic transcriptional suppression and long-term compensatory adaptation by sex-linked genes. Our results have broad implications for the evolution of gene expression in the Drosophila male germline and for genome evolution.

  13. Developmental expression of "germline"- and "sex determination"-related genes in the ctenophore Mnemiopsis leidyi.

    PubMed

    Reitzel, Adam M; Pang, Kevin; Martindale, Mark Q

    2016-01-01

    An essential developmental pathway in sexually reproducing animals is the specification of germ cells and the differentiation of mature gametes, sperm and oocytes. The "germline" genes vasa, nanos and piwi are commonly identified in primordial germ cells, suggesting a molecular signature for the germline throughout animals. However, these genes are also expressed in a diverse set of somatic stem cells throughout the animal kingdom leaving open significant questions for whether they are required for germline specification. Similarly, members of the Dmrt gene family are essential components regulating sex determination and differentiation in bilaterian animals, but the functions of these transcription factors, including potential roles in sex determination, in early diverging animals remain unknown. The phylogenetic position of ctenophores and the genome sequence of the lobate Mnemiopsis leidyi motivated us to determine the compliment of these gene families in this species and determine expression patterns during development. Our phylogenetic analyses of the vasa, piwi and nanos gene families show that Mnemiopsis has multiple genes in each family with multiple lineage-specific paralogs. Expression domains of Mnemiopsis nanos, vasa and piwi, during embryogenesis from fertilization to the cydippid stage, were diverse, with little overlapping expression and no or little expression in what we think are the germ cells or gametogenic regions. piwi paralogs in Mnemiopsis had distinct expression domains in the ectoderm during development. We observed overlapping expression domains in the apical organ and tentacle apparatus of the cydippid for a subset of "germline genes," which are areas of high cell proliferation, suggesting that these genes are involved with "stem cell" specification and maintenance. Similarly, the five Dmrt genes show diverse non-overlapping expression domains, with no clear evidence for expression in future gametogenic regions of the adult. We also

  14. Germline genetic testing to predict drug response and toxicity in oncology--reality or fiction?

    PubMed

    Soh, Thomas I P; Yong, Wei Peng

    2011-08-01

    In addition to 6-mercaptopurine, 5-fluorouracil and irinotecan, the United States Food and Drug Administration (US FDA) has recently recommended label change for tamoxifen, to include pharmacogenetic information on treatment outcome. With the increasing availability of pharmacogenetic testing, on germline as well as somatic mutations, oncologists are now able to identify individuals at risk of severe treatment toxicity or poor treatment response. However, there are still knowledge gaps to fill before rationalised therapy based on pharmacogenetics can be fully integrated into clinical practice. This review provides an overview on the application of pharmacogenetic testing for germ line mutations in oncology to predict response and toxicity.

  15. Identification and characterization of two novel classes of small RNAs in the mouse germline: retrotransposon-derived siRNAs in oocytes and germline small RNAs in testes

    PubMed Central

    Watanabe, Toshiaki; Takeda, Atsushi; Tsukiyama, Tomoyuki; Mise, Kazuyuki; Okuno, Tetsuro; Sasaki, Hiroyuki; Minami, Naojiro; Imai, Hiroshi

    2006-01-01

    Small RNAs ranging in size between 18 and 30 nucleotides (nt) are found in many organisms including yeasts, plants, and animals. Small RNAs are involved in the regulation of gene expression through translational repression, mRNA degradation, and chromatin modification. In mammals, microRNAs (miRNAs) are the only small RNAs that have been well characterized. Here, we have identified two novel classes of small RNAs in the mouse germline. One class consists of ∼20- to 24-nt small interfering RNAs (siRNAs) from mouse oocytes, which are derived from retroelements including LINE, SINE, and LTR retrotransposons. Addition of retrotransposon-derived sequences to the 3′ untranslated region (UTR) of a reporter mRNA destabilizes the mRNA significantly when injected into full-grown oocytes. These results suggest that retrotransposons are suppressed through the RNAi pathway in mouse oocytes. The other novel class of small RNAs is 26- to 30-nt germline small RNAs (gsRNAs) from testes. gsRNAs are expressed during spermatogenesis in a developmentally regulated manner, are mapped to the genome in clusters, and have strong strand bias. These features are reminiscent of Tetrahymena ∼23- to 24-nt small RNAs and Caenorhabditis elegans X-cluster small RNAs. A conserved novel small RNA pathway may be present in diverse animals. PMID:16766679

  16. E-cadherin and APC compete for the interaction with beta-catenin and the cytoskeleton

    PubMed Central

    1994-01-01

    beta-Catenin is involved in the formation of adherens junctions of mammalian epithelia. It interacts with the cell adhesion molecule E- cadherin and also with the tumor suppressor gene product APC, and the Drosophila homologue of beta-catenin, armadillo, mediates morphogenetic signals. We demonstrate here that E-cadherin and APC directly compete for binding to the internal, armadillo-like repeats of beta-catenin; the NH2-terminal domain of beta-catenin mediates the interaction of the alternative E-cadherin and APC complexes to the cytoskeleton by binding to alpha-catenin. Plakoglobin (gamma-catenin), which is structurally related to beta-catenin, mediates identical interactions. We thus show that the APC tumor suppressor gene product forms strikingly similar associations as found in cell junctions and suggest that beta-catenin and plakoglobin are central regulators of cell adhesion, cytoskeletal interaction, and tumor suppression. PMID:7806582

  17. Apoptosis in neural crest cells by functional loss of APC tumor suppressor gene

    NASA Astrophysics Data System (ADS)

    Hasegawa, Sumitaka; Sato, Tomoyuki; Akazawa, Hiroshi; Okada, Hitoshi; Maeno, Akiteru; Ito, Masaki; Sugitani, Yoshinobu; Shibata, Hiroyuki; Miyazaki, Jun-Ichi; Katsuki, Motoya; Yamauchi, Yasutaka; Yamamura, Ken-Ichi; Katamine, Shigeru; Noda, Tetsuo

    2002-01-01

    Apc is a gene associated with familial adenomatous polyposis coli (FAP) and its inactivation is a critical step in colorectal tumor formation. The protein product, adenomatous polyposis coli (APC), acts to down-regulate intracellular levels of -catenin, a key signal transducer in the Wnt signaling. Conditional targeting of Apc in the neural crest of mice caused massive apoptosis of cephalic and cardiac neural crest cells at about 11.5 days post coitum, resulting in craniofacial and cardiac anomalies at birth. Notably, the apoptotic cells localized in the regions where -catenin had accumulated. In contrast to its role in colorectal epithelial cells, inactivation of APC leads to dysregulation of -catenin/Wnt signaling with resultant apoptosis in certain tissues including neural crest cells.

  18. Oral mucosal stigmata in hereditary-cancer syndromes: From germline mutations to distinctive clinical phenotypes and tailored therapies.

    PubMed

    Ponti, Giovanni; Tomasi, Aldo; Manfredini, Marco; Pellacani, Giovanni

    2016-05-10

    Numerous familial tumor syndromes are associated with distinctive oral mucosal findings, which may make possible an early diagnosis as an efficacious marker for the risk of developing visceral malignancies. In detail, Familial Adenomatous Polyposis (FAP), Gardner syndrome, Peutz-Jeghers syndrome, Cowden Syndrome, Gorlin Syndrome, Lynch/Muir-Torre Syndrome and Multiple Endocrine Neoplasia show specific lesions of the oral mucosa and other distinct clinical and molecular features. The common genetic background of the above mentioned syndromes involve germline mutations in tumor suppressor genes, such as APC, PTEN, PTCH1, STK11, RET, clearly implied in both ectodermal and mesodermal differentiation, being the oral mucosal and dental stigmata frequently associated in the specific clinical phenotypes. The oral and maxillofacial manifestations of these syndromes may become visible several years before the intestinal lesions, constituting a clinical marker that is predictive for the development of intestinal polyps and/or other visceral malignancies. A multidisciplinary approach is therefore necessary for both clinical diagnosis and management of the gene-carriers probands and their family members who have to be referred for genetic testing or have to be investigated for the presence of visceral cancers. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. APC mutations as a potential biomarker for sensitivity to tankyrase inhibitors in colorectal cancer.

    PubMed

    Tanaka, Noritaka; Mashima, Tetsuo; Mizutani, Anna; Sato, Ayana; Aoyama, Aki; Gong, Bo; Yoshida, Haruka; Muramatsu, Yukiko; Nakata, Kento; Matsuura, Masaaki; Katayama, Ryohei; Nagayama, Satoshi; Fujita, Naoya; Sugimoto, Yoshikazu; Seimiya, Hiroyuki

    2017-02-08

    In most colorectal cancers (CRCs), Wnt/β-catenin signaling is activated by loss-of-function mutations in the adenomatous polyposis coli (APC) gene and plays a critical role in tumorigenesis. Tankyrases poly(ADP-ribosyl)ate and destabilize Axins, a negative regulator of β-catenin, and upregulate β-catenin signaling. Tankyrase inhibitors downregulate β-catenin and are expected to be promising therapeutics for CRC. However, CRC cells are not always sensitive to tankyrase inhibitors, and predictive biomarkers for the drug sensitivity remain elusive. Here we demonstrate that the short-form APC mutations predict the sensitivity of CRC cells to tankyrase inhibitors. By using well-established CRC cell lines, we found that tankyrase inhibitors downregulated β-catenin in the drug-sensitive but not resistant CRC cells. The drug-sensitive cells showed higher Tcf/LEF transcriptional activity than the resistant cells and possessed 'short' truncated APCs lacking all seven β-catenin-binding 20-amino-acid repeats (20-AARs). By contrast, the drug-resistant cells possessed 'long' APC retaining two or more 20-AARs. Knockdown of the long APCs with two 20-AARs increased β-catenin, Tcf/LEF transcriptional activity and its target gene AXIN2 expression. Under these conditions, tankyrase inhibitors were able to downregulate β-catenin in the resistant cells. These results indicate that the long APCs are hypomorphic mutants whereas they exert a dominant-negative effect on Axin-dependent β-catenin degradation caused by tankyrase inhibitors. Finally, we established 16 patient-derived CRC cells and confirmed that the tankyrase inhibitor-responsive cells harbor the short-form APC mutations. These observations exemplify the predictive importance of APC mutations, the most common genetic alteration in CRCs, for molecular targeted therapeutics.

  20. Black raspberries suppress colonic adenoma development in ApcMin/+ mice: relation to metabolite profiles.

    PubMed

    Pan, Pan; Skaer, Chad W; Wang, Hsin-Tzu; Stirdivant, Steven M; Young, Matthew R; Oshima, Kiyoko; Stoner, Gary D; Lechner, John F; Huang, Yi-Wen; Wang, Li-Shu

    2015-10-01

    Freeze-dried black raspberries (BRBs) have demonstrated chemopreventive effects in a dietary intervention trial with human colorectal cancer patients. The aim of this study was to investigate BRB-caused metabolite changes using the Apc(Min/+) mouse as a model of human colorectal cancer. Wild-type (WT) mice were fed control diet, and Apc(Min/+) mice were fed either control diet or control diet supplemented with 5% BRBs for 8 weeks. Colonic and intestinal polyp size and number were measured. A non-targeted metabolomic analysis was conducted on colonic mucosa, liver and fecal specimens. Eight weeks of BRB treatment significantly decreased intestinal and colonic polyp number and size in Apc(Min/+) mice. The apc gene mutation significantly changed 52 metabolites in colonic mucosa associated with increased amino acid and decreased lipid metabolites, as well as 39 liver and 8 fecal metabolites. BRBs significantly reversed 23 apc-regulated metabolites, including 13 colonic mucosa, 8 liver and 2 fecal metabolites that were involved in amino acid, glutathione, lipid and nucleotide metabolism. Of these, changes in eight metabolites were linearly correlated with decreased colonic polyp number and size in BRB-treated Apc(Min/+) mice. Elevated levels of putrescine and linolenate in Apc(Min/+) mice were significantly decreased by BRBs. Ornithine decarboxylase expression, the key enzyme in putrescine generation, was fully suppressed by BRBs. These results suggest that BRBs produced beneficial effects against colonic adenoma development in Apc(Min/+) mice and modulated multiple metabolic pathways. The metabolite changes produced by BRBs might potentially reflect the BRB-mediated chemopreventive effects in colorectal cancer patients. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. The interrelationship between APC/C and Plk1 activities in centriole disengagement.

    PubMed

    Hatano, Toshiyuki; Sluder, Greenfield

    2012-11-15

    Mother-daughter centriole disengagement, the necessary first step in centriole duplication, involves Plk1 activity in early mitosis and separase activity after APC/C activity mediates securin degradation. Plk1 activity is thought to be essential and sufficient for centriole disengagement with separase activity playing a supporting but non-essential role. In separase null cells, however, centriole disengagement is substantially delayed. The ability of APC/C activity alone to mediate centriole disengagement has not been directly tested. We investigate the interrelationship between Plk1 and APC/C activities in disengaging centrioles in S or G2 HeLa and RPE1 cells, cell types that do not reduplicate centrioles when arrested in S phase. Knockdown of the interphase APC/C inhibitor Emi1 leads to centriole disengagement and reduplication of the mother centrioles, though this is slow. Strong inhibition of Plk1 activity, if any, during S does not block centriole disengagement and mother centriole reduplication in Emi1 depleted cells. Centriole disengagement depends on APC/C-Cdh1 activity, not APC/C-Cdc20 activity. Also, Plk1 and APC/C-Cdh1 activities can independently promote centriole disengagement in G2 arrested cells. Thus, Plk1 and APC/C-Cdh1 activities are independent but slow pathways for centriole disengagement. By having two slow mechanisms for disengagement working together, the cell ensures that centrioles will not prematurely separate in late G2 or early mitosis, thereby risking multipolar spindle assembly, but rather disengage in a timely fashion only late in mitosis.

  2. Prediction of Germline Mutations and Cancer Risk in the Lynch Syndrome

    PubMed Central

    Chen, Sining; Wang, Wenyi; Lee, Shing; Nafa, Khedoudja; Lee, Johanna; Romans, Kathy; Watson, Patrice; Gruber, Stephen B.; Euhus, David; Kinzler, Kenneth W.; Jass, Jeremy; Gallinger, Steven; Lindor, Noralane M.; Casey, Graham; Ellis, Nathan; Giardiello, Francis M.; Offit, Kenneth; Parmigiani, Giovanni

    2008-01-01

    Context Identifying families at high risk for the Lynch syndrome (ie, hereditary non-polyposis colorectal cancer) is critical for both genetic counseling and cancer prevention. Current clinical guidelines are effective but limited by applicability and cost. Objective To develop and validate a genetic counseling and risk prediction tool that estimates the probability of carrying a deleterious mutation in mismatch repair genes MLH1, MSH2, or MSH6 and the probability of developing colorectal or endometrial cancer. Design, Setting, and Patients External validation of the MMRpro model was conducted on 279 individuals from 226 clinic-based families in the United States, Canada, and Australia (referred between 1993–2005) by comparing model predictions with results of highly sensitive germline mutation detection techniques. MMRpro models the autosomal dominant inheritance of mismatch repair mutations, with parameters based on meta-analyses of the penetrance and prevalence of mutations and of the predictive values of tumor characteristics. The model’s prediction is tailored to each individual’s detailed family history information on colorectal and endometrial cancer and to tumor characteristics including microsatellite instability. Main Outcome Measure Ability of MMRpro to correctly predict mutation carrier status, as measured by operating characteristics, calibration, and overall accuracy. Results In the independent validation, MMRpro provided a concordance index of 0.83 (95% confidence interval, 0.78–0.88) and a ratio of observed to predicted cases of 0.94 (95% confidence interval, 0.84–1.05). This results in higher accuracy than existing alternatives and current clinical guidelines. Conclusions MMRpro is a broadly applicable, accurate prediction model that can contribute to current screening and genetic counseling practices in a high-risk population. It is more sensitive and more specific than existing clinical guidelines for identifying individuals who may

  3. Genetic analysis of intestinal polyp development in Collaborative Cross mice carrying the Apc (Min/+) mutation.

    PubMed

    Dorman, Alexandra; Baer, Daria; Tomlinson, Ian; Mott, Richard; Iraqi, Fuad A

    2016-02-19

    Colorectal cancer is an abnormal tissue development in the colon or rectum. Most of CRCs develop due to somatic mutations, while only a small proportion is caused by inherited mutations. Familial adenomatous polyposis is an inherited genetic disease, which is characterized by colorectal polyps. It is caused by inactivating mutations in the Adenomatous polyposis coli gene. Mice carrying and non-sense mutation in Adenomatous polyposis coli gene at site R850, which designated Apc (R850X/+) (Min), develop intestinal adenomas, while the bulk of the disease is in the small intestine. A number of genetic modifier loci of Min have been mapped, but so far most of the underlying genes have not been identified. In our previous studies, we have shown that Collaborative Cross mice are a powerful tool for mapping loci responsible for phenotypic variation. As a first step towards identification of novel modifiers of Min, we assessed the phenotypic variation between 27 F1 crosses between different Collaborative cross mice and C57BL/6-Min lines. Here, C57BL/6-Min male mice were mated with females from 27 Collaborative cross lines. F1 offspring were terminated at 23 weeks old and multiple phenotypes were collected: polyp counts, intestine length, intestine weight, packed cell volume and spleen weight. Additionally, in eight selected F1 Collaborative cross-C57BL/6-Min lines, body weight was monitored and compared to control mice carry wildtype Adenomatous polyposis coli gene. We found significant (p < 0.05) phenotypic variation between the 27 F1 Collaborative cross-C57BL/6-Min lines for all the tested phenotypes, and sex differences with traits; Colon, body weight and intestine length phenotypes, only. Heritability calculation showed that these phenotypes are mainly controlled by genetic factors. Variation in polyp development is controlled, an appreciable extent, by genetic factors segregating in the Collaborative cross population and suggests that it is suited for identifying

  4. Prevalence of mutations in APC, CTNNB1, and BRAF in Tunisian patients with sporadic colorectal cancer.

    PubMed

    Bougatef, Karim; Ouerhani, Slah; Moussa, Amel; Kourda, Nadia; Coulet, Florence; Colas, Chrystelle; Lahely, Yannick Blondeau; Najjar, Tawfik; Ben Jilani, Sarra; Benammar-Elgaaied, Amel; Soubrier, Florent; Marrakchi, Raja

    2008-11-01

    Sporadic colorectal tumorigenesis is caused by alterations in the Wnt (APC, CTNNB1) and Ras pathways. Our objective was to analyze the occurrence of these genetic alterations in relation to tumor and patient characteristics. The prevalence of somatic alteration in the hot-spot regions of the APC, BRAF, and CTNNB1 genes was investigated in 48 unselected and unrelated Tunisian patients with sporadic colorectal cancer, and the association between the molecular features at these genes in relation to tumor and patient characteristics (age at diagnosis, sex, tumor localization, stage, and differentiation) was analyzed. Loss of heterozygosity was observed at the APC locus in 52% of the analyzed tumors. 6 novel mutations were detected by polymerase chain reaction sequencing in the mutation cluster region of the APC gene. No mutations were observed in the CTNNB1 gene in any tumor, but 8% of tumors harbored mutation in the BRAF gene. Clinicopathological analyses showed an association between APC point mutations and the earliest occurrence of sporadic colorectal cancer. The findings confirm the heterogeneity of APC gene alteration and also reveal a particular profile of this pathology among Tunisian patients that confirms the epidemiological data for this country.

  5. A centrosomal Cdc20-APC pathway controls dendrite morphogenesis in postmitotic neurons

    PubMed Central

    Kim, Albert H.; Puram, Sidharth V.; Bilimoria, Parizad M.; Ikeuchi, Yoshiho; Keough, Samantha; Wong, Michael; Rowitch, David; Bonni, Azad

    2009-01-01

    SUMMARY The ubiquitin ligase anaphase-promoting complex (APC) recruits the coactivator Cdc20 to drive mitosis in cycling cells. However, the nonmitotic functions of Cdc20-APC have remained unexplored. We report that Cdc20-APC plays an essential role in dendrite morphogenesis in postmitotic neurons. Knockdown of Cdc20 in cerebellar slices and in postnatal rats in vivo profoundly impairs the formation of granule neuron dendrite arbors in the cerebellar cortex. Remarkably, Cdc20 is enriched at the centrosome in neurons, and the centrosomal localization is critical for Cdc20-dependent dendrite development. We also find that the centrosome-associated protein histone deacetylase 6 (HDAC6) promotes the polyubiquitination of Cdc20, stimulates the activity of centrosomal Cdc20-APC, and drives the differentiation of dendrites. These findings define a novel postmitotic function for Cdc20-APC in the morphogenesis of dendrites in the mammalian brain. The identification of a centrosomal Cdc20-APC ubiquitin signaling pathway holds important implications for diverse biological processes including neuronal connectivity and plasticity. PMID:19167333

  6. Soma-to-germline interactions during Drosophila oogenesis are influenced by dose-sensitive interactions between cut and the genes cappuccino, ovarian tumor and agnostic.

    PubMed Central

    Jackson, S M; Berg, C A

    1999-01-01

    The cut gene of Drosophila melanogaster encodes a homeodomain protein that regulates a soma-to-germline signaling pathway required for proper morphology of germline cells during oogenesis. cut is required solely in somatic follicle cells, and when cut function is disrupted, membranes separating adjacent nurse cells break down and the structural integrity of the actin cytoskeleton is compromised. To understand the mechanism by which cut expression influences germline cell morphology, we determined whether binucleate cells form by defective cytokinesis or by fusion of adjacent cells. Egg chambers produced by cut, cappuccino, and chickadee mutants contained binucleate cells in which ring canal remnants stained with antibodies against Hu-li tai shao and Kelch, two proteins that are added to ring canals after cytokinesis is complete. In addition, defects in egg chamber morphology were observed only in middle to late stages of oogenesis, suggesting that germline cell cytokineses were normal in these mutants. cut exhibited dose-sensitive genetic interactions with cappuccino but not with chickadee or other genes that regulate cytoskeletal function, including armadillo, spaghetti squash, quail, spire, Src64B, and Tec29A. Genomic regions containing genes that cooperate with cut were identified by performing a second-site noncomplementing screen using a collection of chromosomal deficiencies. Sixteen regions that interact with cut during oogenesis and eight regions that interact during the development of other tissues were identified. Genetic interactions between cut and the ovarian tumor gene were identified as a result of the screen. In addition, the gene agnostic was found to be required during oogenesis, and genetic interactions between cut and agnostic were revealed. These results demonstrate that a signaling pathway regulating the morphology of germline cells is sensitive to genetic doses of cut and the genes cappuccino, ovarian tumor, and agnostic. Since these genes

  7. Cdk and APC activities limit the spindle-stabilizing function of Fin1 to anaphase.

    PubMed

    Woodbury, Erika L; Morgan, David O

    2007-01-01

    The fidelity of chromosome segregation depends on proper regulation of mitotic spindle behaviour. In anaphase, spindle stability is promoted by the dephosphorylation of cyclin-dependent kinase (Cdk) substrates, which results from Cdk inactivation and phosphatase activation. Few of the critical Cdk targets have been identified. Here, we identify the budding-yeast protein Fin1 (ref. 7) as a spindle-stabilizing protein whose activity is strictly limited to anaphase by changes in its phosphorylation state and rate of degradation. Phosphorylation of Fin1 from S phase to metaphase, by the cyclin-dependent kinase Clb5-Cdk1, inhibits Fin1 association with the spindle. In anaphase, when Clb5-Cdk1 is inactivated, Fin1 is dephosphorylated by the phosphatase Cdc14. Fin1 dephosphorylation targets it to the poles and microtubules of the elongating spindle, where it contributes to spindle integrity. A non-phosphorylatable Fin1 mutant localizes to the spindle before anaphase and impairs efficient chromosome segregation. As cells complete mitosis and disassemble the spindle, the ubiqutin ligase APC(Cdh1) targets Fin1 for destruction. Our studies illustrate how phosphorylation-dependent changes in the behaviour of Cdk1 substrates influence complex mitotic processes.

  8. Copy number variants associated with 18p11.32, DCC and the promoter 1B region of APC in colorectal polyposis patients

    PubMed Central

    Masson, Amy L.; Talseth-Palmer, Bente A.; Evans, Tiffany-Jane; McElduff, Patrick; Spigelman, Allan D.; Hannan, Garry N.; Scott, Rodney J.

    2015-01-01

    Familial Adenomatous Polyposis (FAP) is the second most common inherited predisposition to colorectal cancer (CRC) associated with the development of hundreds to thousands of adenomas in the colon and rectum. Mutations in APC are found in ~ 80% polyposis patients with FAP. In the remaining 20% no genetic diagnosis can be provided suggesting other genes or mechanisms that render APC inactive may be responsible. Copy number variants (CNVs) remain to be investigated in FAP and may account for disease in a proportion of polyposis patients. A cohort of 56 polyposis patients and 40 controls were screened for CNVs using the 2.7M microarray (Affymetrix) with data analysed using ChAS (Affymetrix). A total of 142 CNVs were identified unique to the polyposis cohort suggesting their involvement in CRC risk. We specifically identified CNVs in four unrelated polyposis patients among CRC susceptibility genes APC, DCC, MLH1 and CTNNB1 which are likely to have contributed to disease development in these patients. A recurrent deletion was observed at position 18p11.32 in 9% of the patients screened that was of particular interest. Further investigation is necessary to fully understand the role of these variants in CRC risk given the high prevalence among the patients screened. PMID:26909336

  9. Copy number variants associated with 18p11.32, DCC and the promoter 1B region of APC in colorectal polyposis patients.

    PubMed

    Masson, Amy L; Talseth-Palmer, Bente A; Evans, Tiffany-Jane; McElduff, Patrick; Spigelman, Allan D; Hannan, Garry N; Scott, Rodney J

    2016-02-01

    Familial Adenomatous Polyposis (FAP) is the second most common inherited predisposition to colorectal cancer (CRC) associated with the development of hundreds to thousands of adenomas in the colon and rectum. Mutations in APC are found in ~ 80% polyposis patients with FAP. In the remaining 20% no genetic diagnosis can be provided suggesting other genes or mechanisms that render APC inactive may be responsible. Copy number variants (CNVs) remain to be investigated in FAP and may account for disease in a proportion of polyposis patients. A cohort of 56 polyposis patients and 40 controls were screened for CNVs using the 2.7M microarray (Affymetrix) with data analysed using ChAS (Affymetrix). A total of 142 CNVs were identified unique to the polyposis cohort suggesting their involvement in CRC risk. We specifically identified CNVs in four unrelated polyposis patients among CRC susceptibility genes APC, DCC, MLH1 and CTNNB1 which are likely to have contributed to disease development in these patients. A recurrent deletion was observed at position 18p11.32 in 9% of the patients screened that was of particular interest. Further investigation is necessary to fully understand the role of these variants in CRC risk given the high prevalence among the patients screened.

  10. THE GERMLINE STEM CELL NICHE UNIT IN MAMMALIAN TESTES

    PubMed Central

    Oatley, Jon M.; Brinster, Ralph L.

    2014-01-01

    This review addresses current understanding of the germline stem cell niche unit in mammalian testes. Spermatogenesis is a classic model of tissue-specific stem cell function relying on self-renewal and differentiation of spermatogonial stem cells (SSCs). These fate decisions are influenced by a niche microenvironment composed of a growth factor milieu that is provided by several testis somatic support cell populations. Investigations over the last two decades have identified key determinants of the SSC niche including cytokines that regulate SSC functions and support cells providing these factors, adhesion molecules that influence SSC homing, and developmental heterogeneity of the niche during postnatal aging. Emerging evidence suggests that Sertoli cells are a key support cell population influencing the formation and function of niches by secreting soluble factors and possibly orchestrating contributions of other support cells. Investigations with mice have shown that niche influence on SSC proliferation differs during early postnatal development and adulthood. Moreover, there is mounting evidence of an age-related decline in niche function, which is likely influenced by systemic factors. Defining the attributes of stem cell niches is key to developing methods to utilize these cells for regenerative medicine. The SSC population and associated niche comprise a valuable model system for study that provides fundamental knowledge about the biology of tissue-specific stem cells and their capacity to sustain homeostasis of regenerating tissue lineages. While the stem cell is essential for maintenance of all self-renewing tissues and has received considerable attention, the role of niche cells is at least as important and may prove to be more receptive to modification in regenerative medicine. PMID:22535892

  11. A nuclear Argonaute promotes multigenerational epigenetic inheritance and germline immortality.

    PubMed

    Buckley, Bethany A; Burkhart, Kirk B; Gu, Sam Guoping; Spracklin, George; Kershner, Aaron; Fritz, Heidi; Kimble, Judith; Fire, Andrew; Kennedy, Scott

    2012-09-20

    Epigenetic information is frequently erased near the start of each new generation. In some cases, however, epigenetic information can be transmitted from parent to progeny (multigenerational epigenetic inheritance). A particularly notable example of this type of epigenetic inheritance is double-stranded RNA-mediated gene silencing in Caenorhabditis elegans. This RNA-mediated interference (RNAi) can be inherited for more than five generations. To understand this process, here we conduct a genetic screen for nematodes defective in transmitting RNAi silencing signals to future generations. This screen identified the heritable RNAi defective 1 (hrde-1) gene. hrde-1 encodes an Argonaute protein that associates with small interfering RNAs in the germ cells of progeny of animals exposed to double-stranded RNA. In the nuclei of these germ cells, HRDE-1 engages the nuclear RNAi defective pathway to direct the trimethylation of histone H3 at Lys 9 (H3K9me3) at RNAi-targeted genomic loci and promote RNAi inheritance. Under normal growth conditions, HRDE-1 associates with endogenously expressed short interfering RNAs, which direct nuclear gene silencing in germ cells. In hrde-1- or nuclear RNAi-deficient animals, germline silencing is lost over generational time. Concurrently, these animals exhibit steadily worsening defects in gamete formation and function that ultimately lead to sterility. These results establish that the Argonaute protein HRDE-1 directs gene-silencing events in germ-cell nuclei that drive multigenerational RNAi inheritance and promote immortality of the germ-cell lineage. We propose that C. elegans use the RNAi inheritance machinery to transmit epigenetic information, accrued by past generations, into future generations to regulate important biological