GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 11
    In: Nature Genetics, Springer Science and Business Media LLC, Vol. 47, No. 5 ( 2015-5), p. 458-468
    Type of Medium: Online Resource
    ISSN: 1061-4036 , 1546-1718
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2015
    detail.hit.zdb_id: 1494946-5
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 12
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 253-253
    Abstract: Background: Acquired aplastic anemia (AA), the prototypical bone marrow failure syndrome, is inferred to result from immune-mediated destruction of hematopoietic progenitors, as most patients respond to immunosuppressive therapies. Clonal hematopoiesis in AA is evident in the presence of paroxysmal nocturnal hemoglobinuria (PNH) cells in as many as half of patients and by identification of uniparental disomies involving 6p (6pUPD) chromosome in 13% of cases. In addition, "clonal transformation", as defined by the development of myelodysplastic syndromes (MDS) or acute myelogenous leukemia (AML) is a serious long-term complication in 10-15% AA patients. Methods: We performed targeted deep sequencing and SNP array-based copy number (CN) analysis of peripheral blood- or granulocyte-derived DNA from 439 patients with AA (280 from US and 159 from Japanese cohorts) for a panel of 103 candidate genes, chosen because they are known to be frequently mutated in myeloid neoplasms. Germline DNA was available for 288 out of 439 patients and was used to confirm the somatic origin of mutations. Whole exome sequencing (WES) was performed in 52 cases. Where serial samples were available, the chronology of detected mutations was also investigated. Results: Targeted deep sequencing provided highly concordant results between the US and Japanese cohorts; approximately one third of AA patients had mutations in genes commonly affected in myeloid neoplasms, and about one third of patients in whom mutations were identified had multiple mutations. Multi-lineage involvement of mutations was confirmed in 6 cases using flow-sorted bone marrow samples. However, compared to myeloid neoplasms, mutations in AA were at much lower variant allele frequencies (VAFs) ( 〈 10% on average) and most frequently involved 5 genes: PIGA, BCOR/BCORL1, DNMT3A and ASXL1 (Fig.1). Although CN abnormalities were rare, about 13% of AA patients in both cohorts showed 6pUPD. Combined, clonal hematopoiesis was detected in as many as 46.5% and 47.8% of US and Japanese patients, respectively. We focused efforts on the large NIH cohort, due to accessible serial samples and well characterized clinical phenotypes at many time points. For 46 cases for which diagnostic samples were available, mutations were detected from at the time of diagnosis but at very low VAFs. The size of DNMT3A or ASXL1 mutated clones tended to increase over time, regardless of the emergence of chromosomal anomalies or blasts, whereas that of BCOR or PIGA mutated clones was more likely to decrease or remain stable. In both patient cohorts, presence of an acquired mutation was associated with older age, but did not correlate with response to immunosuppressive therapy (IST) or overall survival (OS). Mutations in PIGA and BCOR/BCORL1 were more common in AA than in MDS/AML and when combined, were associated with favorable OS (favorable mutations) (P = 0.044). Conversely, 17 high-risk mutations were extracted to predict poor OS (Fig. 2), which combined with favorable mutations, could be used to stratify AA patients with regard to OS (P = 0.0025). WES allowed capture of more mutations and better characterization of clonal hematopoiesis: more than 60% of AA patients had somatic mutations by combined targeted and whole exome sequencing. In 36 cases, WES was performed for all available serial samples, which enabled comprehensive monitoring of the dynamic chronological behavior of hematopoietic clones for as long as a decade after diagnosis. In many cases, clonal hematopoiesis developed gradually and was unrelated to the severity of cytopenias or to clinical evolution to abnormal cytogenetics, marrow dysplasia, and leukemia. Acquisition of new mutations within founder clones and subsequent selection shaped highly complex clonal structures in some cases (Fig. 3). The emergence of clonal hematopoiesis predated the development of MDS or leukemic transformation, with clones often detectable at time of diagnosis. Conclusions: Clonal hematopoiesis in AA was prevalent, associated in about half of cases with mutations in genes recurrently mutated in myeloid neoplasms. The highly biased set of mutated genes associated with clonal hematopoiesis in AA is evidence for Darwinian selection of particular cell clones under in the bone marrow failure environment. Mutations could be used to better predict prognosis of AA patients. Figure 1 Figure 1. Figure 2 Figure 2. Figure 3 Figure 3. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 13
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 73, No. 8_Supplement ( 2013-04-15), p. 4602-4602
    Abstract: Recent genetic studies have revealed a number of novel gene mutations in myeloid malignancies, unmasking an unexpected role of deregulated histone modification and DNA methylation in myeloid neoplasms. However, our knowledge about the spectrum of gene mutations in myeloid neoplasms is still incomplete. So, we analyzed 50 paired tumor-normal samples of myeloid neoplasms using whole exome sequencing, among which we identified recurrent mutations involving STAG2, a core cohesin component, and two other cohesin components, including STAG1 and PDS5B. Cohesin is a multimeric protein complex which is composed of four core subunits (SMC1, SMC3, RAD21 and STAG proteins), and is engaged in cohesion of sister chromatids, DNA repair and transcriptional regulation. To extend the findings in the whole-exome analysis, an additional 534 primary samples of various myeloid neoplasms was examined for mutations and deletions in a total of 9 components of the cohesin complexes, using high-throughput sequencing and SNP arrays. In total, mutations/deletions were found in a variety of myeloid neoplasms, including AML (22/131), CMML (15/86), MDS (26/205), in a mutually exclusive manner. Cohesin mutations frequently coexisted with other common mutations in myeloid neoplasms, significantly associated with spliceosome mutations. Deep sequencing of these mutant alleles revealed that majority of the cohesin mutations existed in the major tumor populations, indicating their early origin during leukemogenesis. Next, we examined several myeloid leukemia cell lines with or without cohesin mutations for expression of each cohesin component and their chromatin-bound fractions. Interestingly, the chromatin-bound fraction of several components of cohesin was significantly reduced in cell lines having mutated or defective cohesin components, suggesting substantial loss of cohesin-bound sites on chromatin. Finally, we introduced the wild-type RAD21 allele into RAD21-mutated cell lines (Kasumi-1), which effectively suppressed the proliferation of Kasumi-1, supporting a leukemogenic role of compromised cohesin functions. Less frequent mutations of cohesin components have been described in other cancers, where impaired cohesion and consequent aneuploidy were implicated in oncogenic action. However, about half of cohesin-mutated cases in our cohort had completely normal karyotypes, suggesting that cohesin-mutated cells were not clonally selected because of aneuploidy. Of note, the number of mutations determined by our whole exome analysis was significantly higher in cohesin-mutated cases compared to non-mutated cases. Since cohesin participates in post-replicative DNA repair, this may suggest that compromised cohesin function could induce DNA hypermutability and contribute to leukemogenesis. In conclusion, our findings highlight a possible role of compromised cohesin functions in myeloid leukemogenesis. Citation Format: Ayana Kon, Lee-Yung Shih, Masashi Minamino, Masashi Sanada, Yuichi Shiraishi, Yasunobu Nagata, Kenichi Yoshida, Yusuke Okuno, Masashige Bando, Shunpei Ishikawa, Aiko Sato-Otsubo, Genta Nagae, Aiko Nishimoto, Claudia Haferlach, Daniel Nowak, Yusuke Sato, Tamara Alpermann, Teppei Shimamura, Hiroko Tanaka, Kenichi Chiba, Ryo Yamamoto, Tomoyuki Yamaguchi, Makoto Otsu, Naoshi Obara, Mamiko Sakata-Yanagimoto, Tsuyoshi Nakamaki, Ken Ishiyama, Florian Nolte, Wolf-Karsten Hofmann, Shuichi Miyawaki, Shigeru Chiba, Hiraku Mori, Hiromitsu Nakauchi, H. Phillip Koeffler, Hiroyuki Aburatani, Torsten Haferlach, Katsuhiko Shirahige, Satoru Miyano, Seishi Ogawa. Recurrent pathway mutations of multiple components of cohesin complex in myeloid neoplasms. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4602. doi:10.1158/1538-7445.AM2013-4602
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2013
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 14
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 74, No. 19_Supplement ( 2014-10-01), p. 2223-2223
    Abstract: Introduction and Objective Testicular germ cell cancer (TGCC) is the most common solid malignancy among young adult males. Cure could be obtained by intensive chemotherapy combined with retroperitoneal lymph node dissection, but often with substantially compromised quality of life. As for the common genetic lesions, somatic mutations and amplifications of KIT are found in about 20%-30% of cases with TGCCs. However, the molecular pathogenesis of TGCC is still poorly understood. In this study, to obtain a better understanding of the genetic basis of TGCC and to identify druggable molecular targets, we performed whole exome sequencing as well as SNP array-based copy number analysis in TGCC. Methods All cases underwent high orchiectomy and were histologically diagnosed as TGCC. Genomic DNA was extracted from fresh frozen specimens of TGCC. Whole exome sequencing was performed for paired tumor/normal DNA from 10 TGCC patients, in which target exomes were captured using SureSelect Human All Exon V5 (Agilent Technologies) and subjected to massively parallel sequencing on the Illumina platform (HiSeq2000). Copy number variants were also interrogated in 40 TGCCs (25 seminomas and 15 non-seminomas) using Affymetrix 250K NspI array. Results TGCC genome was triploid in most cases with high level amplification in12p. Loss of heterozygosity (LOH) of chromosome 4 was frequently observed in both seminoma and non-seminoma, whereas 11q deletion was found predominantly in cases with seminoma. In addition, we identified recurrent focal amplifications involving 4q12 and 22q11, from which KIT and MAPK1 were identified, respectively. In whole exome sequencing, 15 somatic mutations were detected per sample on average, which was relatively lower than other solid malignancies. When combined the results of copy number analysis with those of whole-exome sequencing, genes involved in RAS signaling pathway and chromatin modification were frequently altered in TGCC. Conclusions Our comprehensive analyses revealed genomic aberrations of TGCC in terms of copy number alterations and gene mutations. Mutated/amplified KIT and MAPK1 and other RAS pathway gene could be potential targets of small molecule inhibitors for therapeutics. Citation Format: Yusuke Sato, Aiko Sato-Otsubo, Yasunobu Nagata, Kenichi Yoshida, Yuichi Shiraishi, Hiromichi Suzuki, Masashi Sanada, Haruki Kume, Satoru Miyano, Yukio Homma, Seishi Ogawa. Genome-wide analysis of copy number alterations and gene mutations in testicular germ cell cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2223. doi:10.1158/1538-7445.AM2014-2223
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2014
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 15
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. 5119-5119
    Abstract: MDS are a group of myeloid neoplasms characterized by deregulated blood cell production and a high propensity to AML. Although a number of gene alterations have been implicated in the pathogenesis of MDS, they do not fully explain the pathogenesis of MDS. So, in order to clarify a comprehensive registry of gene mutations in MDS, we performed whole-exome sequencing of 29 cases with MDS and related myeloid neoplasm. A total of 268 somatic mutations or 9.2 mutations per sample were identified. Among these 9 genes were mutated in more than 2 cases, which not only included a spectrum of known gene targets in MDS, but also affected previously unknown genes that are commonly involved in RNA splicing pathway, including U2AF35, SRSF2 and ZRSR2. Together with additional three (SF3A1, SF3B1 and PRPF40B) found in single cases, 16 (55.2%) of the 29 discovery cases carried a mutation affecting the component of the splicing machinery. To confirm the observation, we examined 9 spliceosome genes for mutations in a large set of myeloid neoplasms. In total, 219 mutations were identified in 209 out of the 582 samples of myeloid neoplasms. RNA splicing pathway mutations were highly specific to myelodysplasia, including 19 of 23 (83%) cases with RARS, 43 of 50 (86%) RCMD-RS, 68 of 155 (44%) other MDS, 48 of 88 (55%) CMML, and 16 of 62 (26%) secondary AML with MDS features with a string preference of SF3B1 mutations to RARS and RCMD-RS and of SRSF2 to CMML, while they were rare in cases with de novo AML and MPN. Significantly, these mutations occurred in an almost completely mutually exclusive manner among mutated cases, suggesting the importance of deregulated RNA splicing in the pathogenesis of MDS. RNA splicing plays critical roles in differentiation, development, and disease and is a major source for protein diversity in higher eukaryotes. Splicing pathway mutations in myelodysplasia commonly affected those components of the splicing complex that are engaged in the 3′ splice site recognition, strongly indicating production of unspliced or aberrantly spliced RNA species are incriminated for the pathogenesis of MDS. So, to clarify the effect of these splicing mutations on RNA splicing, we expressed the wild-type and the mutant U2AF35 or SRSF2 in HeLa cells and performed whole transcriptome analysis in these cells. The results of exon array showed that the wild-type U2AF35 promoted RNA splicing correctly, whereas the mutant U2AF35 inhibited this processes and rendered intronic sequences to remain unspliced. RNA sequencing additionally showed that the number of reads that encompassed the exon/intron junctions was significantly increased in mutant U2AF35-transduced cells. This result means that mutant U2AF35 actually induced impaired 3′-splice site recognition during pre-mRNA processing. In conclusion, our study demonstrated that abnormal RNA splicing caused by mutations of multiple genes on RNA splicing pathway is a common feature of myelodysplasia. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5119. doi:1538-7445.AM2012-5119
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2012
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 16
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. 5122-5122
    Abstract: Myelodysplastic syndromes (MDS) are a heterogeneous group of chronic myeloid neoplasms showing a predisposition to acute myeloid leukemia (AML). The recent discovery of novel pathway mutations of the RNA splicing machinery provided a new insight into the pathogenesis of MDS. These splicing pathway mutations are highly prevalent among all MDS subtypes, accounting for 45 to 85% of the cases. However, the frequency of mutations shows substantial variations among disease subtypes, the genetic/biological basis of which has not been clarified. In addition, the impact of splicing pathway mutations on prognosis has been poorly defined. To explore the genetic basis for these differences, we analyzed genome-wide copy number lesions and the spectrum of gene mutations that may coexist with splicing pathway mutations in a set of 283 cases with myelodysplasia, using SNP array karyotyping and target sequencing of common gene targets in MDS, including TET2 and EZH2. The effects of the splicing pathway mutations on clinical outcomes were evaluated together with those of these accompanying genetic lesions. Splicing pathway mutations were identified in 160 (57%) among 8 components of the splicing machinery, which occurred in a mutually exclusive manner. SNP array karyotyping revealed 138 cases (49%) showing copy number alterations, in which 7q- and/or 5q- were the most frequent abnormalities. Interestingly, the splicing pathway mutations were found at a significantly lower frequency among patients with 7q- and/or 5q- (p & lt;0.0001), where multivariate analysis revealed that 7q- and/or 5q- were independently and significantly associated with the lower frequency of spliceosome mutation (p = 0.001 for 7q- and p = 0.029). 7q- and/or 5q- with complex karyotypes were associated with a significantly poor prognosis (p = 0.025, log-rank test), the presence of the splicing pathway mutations had no impact on prognosis. Interestingly, however, the presence of 7q- and/or 5q- do not seem to be a risk of poor prognosis among those patients carrying a splicing pathway mutation, suggesting that the presence of a splicing pathway mutation could have a beneficial effect on the prognosis of patients with 7q- and/or 5q-. In total, 172mutations were identified among 117 samples, including 41 TET2 (25%), 32 RUNX1 (20%), 26 ASXL1 (16%), 24 RAS (15%), 22 TP53 (14%), 17 IDH1/2 (10%), 10 CBL (6%) and 10 EZH2 (6%) mutations. No specific association between splicing pathway mutations and other coexisting mutations, except that the SRSF2 mutations were significantly associated with lower numbers of accompanying gene mutations compared with that of the U2AF35 mutations (N=14) (OR 6.2 95%CI 1.1-35), which may be of potential interest in the light of the previous report that SRSF2 was involved in the regulation of DNA stability and that depletion of SRSF2 can induce genomic stability. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5122. doi:1538-7445.AM2012-5122
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2012
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 17
    In: Blood, American Society of Hematology, Vol. 120, No. 21 ( 2012-11-16), p. 984-984
    Abstract: Abstract 984 Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome, characterized by red blood cell aplasia, macrocytic anemia, and increased risk of malignancy. Approximately 90% of patients present during the first year of life or in early childhood. About 40–50% of DBA cases are familial with autosomal dominant, while the remainder is sporadic cases whose mode of inheritance is largely unknown. Although anemia is the most prominent feature of DBA, up to 40% of patients also accompany other symptoms including growth retardation and/or a variety of congenital malformations. Recent studies have shown that the disease could be associated with heterozygous mutations in ribosomal protein (RP) genes, including six small subunit RP genes RPS7, RPS10, RPS17, RPS19, RPS24, and RPS26 as well as four large subunit RP genes RPL5, RPL11, RPL26, and RPL35A, which collectively account for about 50% of patients with DBA. In addition, germline mutations in the GATA1 gene encoding a hematopoietic transcription factor, have been also reported in two DBA families. However, it is clear that the molecular etiology of many DBA cases remains to be covered. To identify new mutations that are responsible for DBA, we performed whole-exome sequencing on 40 DBA patients with no documented mutations/deletions involving known DBA genes. After excluding all variants registered in the 1000 Genomes Project, or dbSNP131, or found in our inhouse SNP database, we searched for non-synonymous mutations involving RP genes as possible candidate for novel DBA genes. In this study, we identified probable pathogenic mutations in two novel RP genes, RPS27 and RPL27 in two patients. The first case was a 1-year-old girl who harbored a single nucleotide substitution at the splice acceptor site in intron 1 of RPL27 (c.-2–1G 〉 A), which results in splicing error. She had atrial septal defect and pulmonary stenosis, and responded to steroid treatment. The second case was a 2-year-old girl carrying a frameshift deletion of RPS27 (c.90delC, p.Tyr31ThrfsX5), leading to a premature truncation. This patient had no abnormalities and responded to steroid treatment. An additional five missense SNVs affecting single cases was identified in five genes, including RPL3L, RPL8, RPL13, RPL18A, and RPL31, together with two in-frame deletions of RPL6 and RPL14 in two patients, which cause deletion of a single amino-acid. However, the pathological significance in these 7 cases is uncertain. In the remaining 31 patients, no mutations were detected in RP genes. In conclusion, we identified novel germline mutations of RP genes that could be responsible for DBA, further confirming the concept that the RP genes are common targets of germline mutations in DBA patients and also suggested the presence of non-RP gene targets for DNA. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2012
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 18
    In: Blood, American Society of Hematology, Vol. 126, No. 23 ( 2015-12-03), p. 113-113
    Abstract: Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell neoplasm of largely unknown genetic basis, which is associated with human T-cell leukemia virus type-1 (HTLV-1) infection. To delineate a genetic landscape of somatic alterations in ATL, we have performed an integrated genetic study, in which whole-genome/exome (WGS/WES) and transcriptome sequencing (RNA-seq) was performed for a cohort of 83 paired ATL samples, followed by extensive validation using targeted sequencing of detected mutations in 370 follow-up samples. A striking feature of driver lesions in ATL was their strong enrichment in the components of T-cell receptor (TCR) / NF-κB pathway. Accounting for more than 90% of ATL cases, these lesions were characterized by the predominance of activating alterations, including hotspot missense mutations in PLCG1 (36%), PRKCB (33%), CARD11 (24%), VAV1 (18%), IRF4 (14%) and FYN (4%). Among these, most frequently mutated was PLCG1, which encodes phospholipase C γ1 (PLCγ1), a key regulator of the proximal TCR signaling. Besides the S345F and S520F mutations recently reported in cutaneous T-cell lymphoma, we identified an additional hotspot mutations (R48W, E1163K, and D1165H). The second most frequently mutated gene was PRKCB, encoding a member of the protein kinase C (PKC) family of proteins (PKCβ), a pivotal signaling molecule downstream of PLCγ. The frequent mutations of PKCβ were unexpected, because it is PKCθ that has been implicated in TCR signaling, whereas PKCβ has been more focused in the context of B-cell receptor signaling. Approximately 93% of the PRKCB mutations were confined to the catalytic domain with a prominent hotspot at D427, suggesting gain-of-function nature of these mutations. Consistent with this, when transduced with the D427N PKCβ mutant, HEK293T and/or Jurkat cells showed increased membrane translocation after PMA/Ionomycin-stimulation, enhanced IKK phosphorylation and p65 nuclear translocation, and augmented NF-κB transcription, compared to wild-type PKCβ-transduced cells. Thus, these PRKCB mutations are the first activating mutations of this family identified in human cancers. Downstream to PKC lies CARD11, a scaffolding protein required for antigen receptor-induced NF-κB activation. Although previously reported in B-cell lymphomas, CARD11 mutations were more common in ATL (24%). In B-cell lymphomas, mutations are largely limited to the coiled-coil (CC) domain, whereas in ATL, they were clustered not only within the CC domain, but also within the PKC-responsive inhibitory domain, showing a prominent mutational hotspot at E626. The inhibitory domain has been implicated in autoinhibition, whose deletion leads to constitutive activation of CARD11. Intriguingly, WGS identified small intragenic deletions confined to this domain (exons 14-17) in 4 cases (8%) without canonical mutations, and RNA-seq confirmed the skipping of the corresponding exons in these cases. Remarkably, CARD11 mutation significantly co-occurred with PRKCBmutations, suggesting potential functional synergism between these lesions. Actually, overexpression of wild-type CARD11 induced NF-κB activation, which was further augmented by E626K mutation. Similarly, when both CARD11 (E626K) and PRKCB (D427N) mutants were co-expressed, more enhanced NF-κB activation was observed. RNA-seq and follow-up RT-PCR screening also identified novel gene fusions in TCR / NF-κB pathway: five CTLA4-CD28 and three ICOS-CD28 fusions were observed in seven (7%) of the 105 cases examined, of whom one patient carried both chimeric fusions. WGS revealed tandem duplications of 2q33.2 segments containing CD28, CTLA4, and ICOS, compatible with the corresponding fusion transcripts. B7/CD28 co-signaling molecules, including CD28, CTLA4, and ICOS co-receptors, play pivotal roles in positive and negative regulations of TCR signaling. All the predicted chimeric proteins had the cytoplasmic part of CD28, and are expected to be expressed under the control of the regulatory element of CTLA4 or ICOS, likely leading to prolonged expression of CD28 co-stimulator. Our findings suggest that deregulated TCR / NF-κB pathway caused by genetic alterations is a hallmark of ATL pathogenesis. The predominance of gain-of-function mutations in this pathway offers good opportunities for exploiting these mutations for the targets of novel drugs to better manage patients. Disclosures Tobinai: Gilead Sciences: Research Funding. Miyazaki:Sumitomo Dainippon: Honoraria; Celgene Japan: Honoraria; Chugai: Honoraria, Research Funding; Shin-bio: Honoraria; Kyowa-Kirin: Honoraria, Research Funding. Watanabe:Daiichi Sankyo Co., Ltd.: Research Funding.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2015
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 19
    In: Blood, American Society of Hematology, Vol. 120, No. 21 ( 2012-11-16), p. 535-535
    Abstract: Abstract 535 Background Transient abnormal myelopoiesis (TAM) represents a self-limited proliferation exclusively affecting perinatal infants with Down syndrome (DS), morphologically and immunologically characterized by immature blasts indistinguishable from acute megakaryoblastic leukemia (AMKL). Although spontaneous regression is as a rule in most cases, about 20–30% of the survived infants develop non-self-limited AMKL (DS-AMKL) 3 to 4 years after the remission. As for the molecular pathogenesis of these DS-related myeloid proliferations, it has been well established that GATA1 mutations are detected in virtually all TAM cases as well as DS-AMKL. However, it is still open to question whether a GATA1 mutation is sufficient for the development of TAM, what is the cellular origin of the subsequent AMKL, whether additional gene mutations are required for the progression to AMKL, and if so, what are their gene targets, although several genes have been reported to be mutated in occasional cases with AMKL, including JAK2/3, TP53 and FLT3. Methods To answer these questions, we identify a comprehensive spectrum of gene mutations in TAM/AMKL cases using whole genome sequencing of three trio samples sequentially obtained at initial presentation of TAM, during remission and at the subsequent relapse phase of AMKL. Whole exome sequencing was also performed for TAM (N=16) and AMKL (N=15) samples, using SureSelect (Agilent) enrichment of 50M exomes followed by high-throughput sequencing. The recurrent mutations in the discovery cohort were further screened in an extended cohort of DS-AMKL (N = 35) as well as TAM (N = 26) and other AMKL cases (N = 19) using target deep sequencing. Results TAM samples had significantly fewer numbers of somatic mutations compared to AMKL samples with the mean numbers of all mutations of 30 (1.0/Mb) and 180 (6.0/Mb) per samples in whole genome sequencing or non-silent somatic mutations of 1.73 and 5.71 per sample in whole exome sequencing in TAM and AMKL cases, respectively (p=0.001). Comprehensive detections of the full spectrum of mutations together with subsequent deep sequencing of the individual mutations allowed to reveal more complicated clonological pictures of clonal evolutions leading to AMKL. In every patient, the major AMKL clones did not represent the direct offspring from the dominant TAM clone. Instead, the direct ancestor of the AMKL clones could be back-traced to a more upstream branch-point of the evolution before the major TAM clone had appeared or, as previously reported, to an earlier founder having an independent GATA1 mutation. Intratumoral heterogeneity was evident at the time of diagnosis as the presence of major subpopulations in both TAM and AMKL populations, which were more often than not characterized by RAS pathway mutations. While GATA1 was the only recurrent mutational target in the TAM phase, 8 genes were recurrently mutated in AMKL samples in whole genome/exome sequencing, including NRAS, TP53 and other novel gene targets that had not been previously reported to be mutated in other neoplasms. The recurrent mutations found in the discovery cohort, in addition to known mutational targets in myeloid malignancies, were screened in an extended cohort of DS-associated myeloid disorders (N=61) as well as other AMKL cases, using high-throughput sequencing of SureSelect-captured and/or PCR amplified targets. Secondary mutations other than GATA1 mutations were found in 3 out of 26 TAM, 20 out of 35 DS-AMKL and 4 out of 19 other AMKL cases. Conclusion TAM is characterized by a paucity of somatic mutations and thought to be virtually caused by a GATA1 mutation in combination with constitutive trisomy 21. Subsequent AMKL evolved from a minor independent subclone acquiring additional mutations. Secondary genetic hits other than GATA1 mutations were common, where deregulated epigenetic controls as well as abnormal signaling pathway mutations play a major role. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2012
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 20
    In: Blood, American Society of Hematology, Vol. 120, No. 21 ( 2012-11-16), p. 782-782
    Abstract: Abstract 782 Recent genetic studies have revealed a number of novel gene mutations in myeloid malignancies, unmasking an unexpected role of deregulated histone modification and DNA methylation in both acute and chronic myeloid neoplasms. However, our knowledge about the spectrum of gene mutations in myeloid neoplasms is still incomplete. In the previous study, we analyzed 29 paired tumor-normal samples with chronic myeloid neoplasms with myelodysplastic features using whole exome sequencing (Yoshida et al., Nature 2011). Although the major discovery was frequent spliceosome mutations tightly associated with myelodysplasia phenotypes, hundreds of unreported gene mutations were also identified, among which we identified recurrent mutations involving STAG2, a core cohesin component, and also two other cohesin components, including STAG1 and PDS5B. Cohesin is a multimeric protein complex conserved across species and is composed of four core subunits, i.e., SMC1, SMC3, RAD21 and STAG proteins, together with several regulatory proteins. Forming a ring-like structure, cohesin is engaged in cohesion of sister chromatids in mitosis, post-replicative DNA repair and regulation of gene expression. To investigate a possible role of cohesin mutations in myeloid leukemogenesis, an additional 534 primary specimens of various myeloid neoplasms was examined for mutations in a total of 9 components of the cohesin and related complexes, using high-throughput sequencing. Copy number alterations in cohesin loci were also interrogated by SNP arrays. In total, 58 mutations and 19 deletions were confirmed by Sanger sequencing in 73 out of 563 primary myeloid neoplasms (13%). Mutations/deletions were found in a variety of myeloid neoplasms, including AML (22/131), CMML (15/86), MDS (26/205) and CML (8/65), with much lower mutation frequencies in MPN (2/76), largely in a mutually exclusive manner. In MDS, mutations were more frequent in RCMD and RAEB (19.5%) but rare in RA, RARS, RCMD-RS and 5q- syndrome (3.4%). Cohesin mutations were significantly associated with poor prognosis in CMML, but not in MDS cases. Cohesin mutations frequently coexisted with other common mutations in myeloid neoplasms, significantly associated with spliceosome mutations. Deep sequencing of these mutant alleles was performed in 19 cases with cohesin mutations. Majority of the cohesin mutations (16/19) existed in the major tumor populations, indicating their early origin during leukemogenesis. Next, we investigated a possible impact of mutations on cohesin functions, where 17 myeloid leukemia cell lines with or without cohesin mutations were examined for expression of each cohesin component and their chromatin-bound fractions. Interestingly, the chromatin-bound fraction of one or more components of cohesin was substantially reduced in cell lines having mutated or defective cohesin components, suggesting substantial loss of cohesin-bound sites on chromatin. Finally, we examined the effect of forced expression of wild-type cohesin on cell proliferation of cohesin-defective cells. Introduction of the wild-type RAD21 and STAG2 suppressed the cell growth of RAD21- (Kasumi-1 and MOLM13) and STAG2-defective (MOLM13) cell lines, respectively, supporting a leukemogenic role of compromised cohesin functions. Less frequent mutations of cohesin components have been described in other cancers, where impaired cohesion and consequent aneuploidy were implicated in oncogenic action. However, 23 cohesin-mutated cases of our cohort had completely normal karyotypes, suggesting that cohesin-mutated cells were not clonally selected because of aneuploidy. Alternatively, a growing body of evidence suggests that cohesin regulate gene expression, arguing for the possibility that cohesin mutations might participate in leukemogenesis through deregulated gene expression. Of additional note, the number of non-silent mutations determined by our whole exome analysis was significantly higher in 6 cohesin-mutated cases compared to non-mutated cases. Since cohesin also participates in post-replicative DNA repair, this may suggest that compromised cohesin function could induce DNA hypermutability and contribute to leukemogenesis. In conclusion, we report a new class of common genetic targets in myeloid malignancies, the cohesin complex. Our findings highlight a possible role of compromised cohesin functions in myeloid leukemogenesis. Disclosures: Haferlach: MLL Munich Leukemia Laboratory: Equity Ownership. Alpermann:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2012
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...