Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA127433 | ENA |
REPOSITORIES: ENA
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Project description:We performed single-molecule telomere length and telomere fusion analysis in patients at different stages of chronic lymphocytic leukaemia (CLL). Our work identified the shortest telomeres ever recorded in primary human tissue reinforcing the concept that there is significant cell division in CLL. Furthermore, we provide direct evidence that critical telomere shortening, dysfunction and fusion contribute to disease progression. The frequency of short telomeres and fusion events increased with advanced disease, but importantly these were also found in a subset of early-stage patient samples indicating that these events can precede disease progression. Sequence analysis of fusion events isolated from individuals with the shortest telomeres revealed limited numbers of repeats at the breakpoint, sub-telomeric deletion and microhomology. Array-CGH analysis of individuals displaying evidence of telomere dysfunction revealed large-scale genomic rearrangements that were concentrated in the telomeric regions; this was not observed in samples with longer telomeres. Array CGH was undertaken on six individuals (five CLL stage C and one stage A) that displayed evidence of telomere dysfunction, and four (three CLL stage A and one stage B) that displayed longer and apparently stable telomeres.
2010-05-28 | E-GEOD-22016 | biostudies-arrayexpress
Project description:We performed single-molecule telomere length and telomere fusion analysis in patients at different stages of chronic lymphocytic leukaemia (CLL). Our work identified the shortest telomeres ever recorded in primary human tissue reinforcing the concept that there is significant cell division in CLL. Furthermore, we provide direct evidence that critical telomere shortening, dysfunction and fusion contribute to disease progression. The frequency of short telomeres and fusion events increased with advanced disease, but importantly these were also found in a subset of early-stage patient samples indicating that these events can precede disease progression. Sequence analysis of fusion events isolated from individuals with the shortest telomeres revealed limited numbers of repeats at the breakpoint, sub-telomeric deletion and microhomology. Array-CGH analysis of individuals displaying evidence of telomere dysfunction revealed large-scale genomic rearrangements that were concentrated in the telomeric regions; this was not observed in samples with longer telomeres.
2010-05-28 | GSE22016 | GEO
Project description:Background and Aims: Telomere dysfunction can increase tumor initiation by induction of chromosomal instability, but initiated tumor cells need to reactivate telomerase for genome stabilization and tumor progression. However, this concept has not been proven in vivo since appropriate mouse models were lacking. Here, we analyzed hepatocarcinogenesis (i) in a novel mouse model of inducible telomere dysfunction on a telomerase-proficient background, (ii) in telomerase knockout mice with chronic telomere dysfunction (G3 mTerc-/-), and (iii) in wild-type mice with functional telomeres and telomerase. Transient or chronic telomere dysfunction enhanced the rates of chromosomal aberrations during hepatocarcinogenesis, but only telomerase-proficient mice exhibited significantly increased rates of macroscopic tumor formation and cancer cell proliferation in response to telomere dysfunction. In contrast, telomere dysfunction resulted in pronounced accumulation of DNA damage, cell cycle arrest and apoptosis in telomerase-deficient liver tumors. Together, these data provide the first in vivo evidence that transient telomere dysfunction during early and late stages of tumorigenesis can promote chromosomal instability and carcinogenesis in telomerase-proficient mice in the absence of additional genetic checkpoint defects at germline level. RNA from liver tumors derived from from DEN treated TTD+ mice TTD- mice and RNA from normal liver 48h-72h after doxycycline induced transient telomere dysfunction in TTD+ and TTD- liver were isolated and RNA was extracted. Agilent Mouse 4x44K v2 arrays were used. DNA from liver tumors and corrresponding kidney as control derived from from DEN treated TTD+ mice, TTD- mice and mTERC-/- G3 mice was isolated and extracted using Phenol/Chloroform. Agilent Mouse 4x44K and Mouse 1x244K arrays were used.
2012-03-30 | E-GEOD-36813 | biostudies-arrayexpress
Project description:Background and Aims: Telomere dysfunction can increase tumor initiation by induction of chromosomal instability, but initiated tumor cells need to reactivate telomerase for genome stabilization and tumor progression. However, this concept has not been proven in vivo since appropriate mouse models were lacking. Here, we analyzed hepatocarcinogenesis (i) in a novel mouse model of inducible telomere dysfunction on a telomerase-proficient background, (ii) in telomerase knockout mice with chronic telomere dysfunction (G3 mTerc-/-), and (iii) in wild-type mice with functional telomeres and telomerase. Transient or chronic telomere dysfunction enhanced the rates of chromosomal aberrations during hepatocarcinogenesis, but only telomerase-proficient mice exhibited significantly increased rates of macroscopic tumor formation and cancer cell proliferation in response to telomere dysfunction. In contrast, telomere dysfunction resulted in pronounced accumulation of DNA damage, cell cycle arrest and apoptosis in telomerase-deficient liver tumors. Together, these data provide the first in vivo evidence that transient telomere dysfunction during early and late stages of tumorigenesis can promote chromosomal instability and carcinogenesis in telomerase-proficient mice in the absence of additional genetic checkpoint defects at germline level.
2012-03-31 | GSE36813 | GEO
Project description:This study describes a recurrent dicentric chromosome formed by telomere fusion between chromosome 20 and chromosome 22 in myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). This is the first description of a recurrent telomere fusion event in myeloid malignancy. The derivative chromosome is further characterised by the presence of nucleolus organiser region material from the chromosome 22 short arm, loss of the putative tumour suppressor gene at 20q12 and secondary rearrangements including gain or amplification of 20q material adjacent to the deletion encompassing 20q12. The presence of residual telomere sequence at the site of translocation in three of the four cases is compelling support for telomere fusion, and supports previous evidence that over half of dicentric chromosomes involving 20q are produced by telomere fusion events. We propose that the sequence of events producing this chromosome abnormality is initial formation of an unstable dicentric chromosome by 20q and 22p telomere fusion, followed by breakage-fusion-bridge cycles causing 20q12 deletion and 20q11.2 gain which provide a growth advantage to the cell. Selection of these clones contributes to leukaemogenesis. Finding recurrent patterns in the complex genome reorganisation events which characterise poor prognosis, complex karyotype AML and MDS will help us understand the mechanisms and oncogenic driver mutations in these poorly understood malignancies. The sample consists of leukaemia specimens from three different cases of AML and MDS. The consistent feature was the presence of a dicentric chromosome formed from chromosomes 20 and 22.
2016-06-30 | E-GEOD-64050 | biostudies-arrayexpress
Project description:Title: Gene expression analysis of indolent and aggressive forms of Chronic Myeloid Leukaemia (CML). Description: Chronic Myeloid Leukaemia presents in chronic phase (CP) and terminates in 'blast crisis'. Despite a common abnormality, the duration of CP is variable. The aim is to compare the gene expression profiles of the indolent and aggressive forms of CML. All samples were taken within 3 months of first diagnosis. Indolent patients were defined by chronic phase CML, duration minimum 7 years. Aggressive patients were defined by chronic phase, duration maximum 3 years.
2013-01-30 | E-MIMR-17 | biostudies-arrayexpress
Project description:LYN kinase is a tyrosine kinase, that regulates cellular homeostasis in a context-specific manner. Our group could show, that its expression in the leukemic microenvironment of chronic lymphocytic leukemia contributes to disease progression (Nguyen PH et al.; Cancer Cell; 2016). To analyze the effect of LYN kinase on the leukemia supportive phenotype of the bone marrow stromal cell line HS-5, we generated single cell clones of LYN deficient stroma cells. These cells were analyzed in a Multi-Omic approach, including ARNA-Seq of stromal cells after 72h of coculture with primary human chronic lymphocytic leukaemia (CLL) samples.
2023-02-10 | E-MTAB-12629 | biostudies-arrayexpress
Project description:This study describes a recurrent dicentric chromosome formed by telomere fusion between chromosome 20 and chromosome 22 in myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). This is the first description of a recurrent telomere fusion event in myeloid malignancy. The derivative chromosome is further characterised by the presence of nucleolus organiser region material from the chromosome 22 short arm, loss of the putative tumour suppressor gene at 20q12 and secondary rearrangements including gain or amplification of 20q material adjacent to the deletion encompassing 20q12. The presence of residual telomere sequence at the site of translocation in three of the four cases is compelling support for telomere fusion, and supports previous evidence that over half of dicentric chromosomes involving 20q are produced by telomere fusion events. We propose that the sequence of events producing this chromosome abnormality is initial formation of an unstable dicentric chromosome by 20q and 22p telomere fusion, followed by breakage-fusion-bridge cycles causing 20q12 deletion and 20q11.2 gain which provide a growth advantage to the cell. Selection of these clones contributes to leukaemogenesis. Finding recurrent patterns in the complex genome reorganisation events which characterise poor prognosis, complex karyotype AML and MDS will help us understand the mechanisms and oncogenic driver mutations in these poorly understood malignancies.
2016-06-30 | GSE64050 | GEO
Project description:miRNAseq of chronic lymphocytic leukaemia (CLL) subsets comprising of Unmutated CLL and Mutated CLL. Mutated CLL cases were further subdivided based on B cell receptor signalling capacity.
2023-05-11 | E-MTAB-12017 | biostudies-arrayexpress
Project description:RNAseq of chronic lymphocytic leukaemia (CLL) subsets comprising of Unmutated CLL and Mutated CLL. Mutated CLL cases were further subdivided based on B cell receptor signalling capacity.
2023-05-11 | E-MTAB-12023 | biostudies-arrayexpress