Spontaneous Cell Fusions as a Mechanism of Parasexual Recombination in Tumor Cell Populations
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PROVIDER: PRJNA670182 | ENA |
REPOSITORIES: ENA
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Project description:Initiation and progression of cancers reflect the underlying process of somatic evolution, which follows a Darwinian logic, i.e., diversification of heritable phenotypes provides a substrate for natural selection, resulting in the outgrowth of the most fit subpopulations. Although somatic evolution can tap into multiple sources of diversification, it is assumed to lack access to (para)sexual recombination – a key diversification mechanism throughout all strata of life. Based on observations of spontaneous fusions involving cancer cells, reported genetic instability of polypoid cells, and precedence of fusion-mediated parasexual recombination in fungi, we asked whether cell fusions could serve as a source of parasexual recombination in cancer cell populations. Using differentially labelled tumor cells, we found evidence of low-frequency, spontaneous cell fusions between carcinoma cells in multiple cell line models of breast cancer both in vitro and in vivo. While some hybrids remained polyploid, many displayed partial ploidy reduction, generating diverse progeny with heterogeneous inheritance of parental alleles, indicative of partial recombination. Hybrid cells also displayed elevated levels of phenotypic plasticity, which may further amplify the impact of cell fusions on the diversification of phenotypic traits. Using mathematical modeling, we demonstrated that the observed rates of spontaneous somatic cell fusions may enable populations of tumor cells to amplify clonal heterogeneity, thus facilitating the exploration of larger areas of the adaptive landscape, relative to strictly asexual populations, which may substantially accelerate a tumor’s ability to adapt to new selective pressures.
2020-09-12 | GSE157845 | GEO
Project description:Initiation and progression of cancers reflect the underlying process of somatic evolution, which follows a Darwinian logic, i.e., diversification of heritable phenotypes provides a substrate for natural selection, resulting in the outgrowth of the most fit subpopulations. Although somatic evolution can tap into multiple sources of diversification, it is assumed to lack access to (para)sexual recombination – a key diversification mechanism throughout all strata of life. Based on observations of spontaneous fusions involving cancer cells, reported genetic instability of polypoid cells, and precedence of fusion-mediated parasexual recombination in fungi, we asked whether cell fusions could serve as a source of parasexual recombination in cancer cell populations. Using differentially labelled tumor cells, we found evidence of low-frequency, spontaneous cell fusions between carcinoma cells in multiple cell line models of breast cancer both in vitro and in vivo. While some hybrids remained polyploid, many displayed partial ploidy reduction, generating diverse progeny with heterogeneous inheritance of parental alleles, indicative of partial recombination. Hybrid cells also displayed elevated levels of phenotypic plasticity, which may further amplify the impact of cell fusions on the diversification of phenotypic traits. Using mathematical modeling, we demonstrated that the observed rates of spontaneous somatic cell fusions may enable populations of tumor cells to amplify clonal heterogeneity, thus facilitating the exploration of larger areas of the adaptive landscape, relative to strictly asexual populations, which may substantially accelerate a tumor’s ability to adapt to new selective pressures.
2020-10-21 | GSE159680 | GEO
Project description:Initiation and progression of cancers reflect the underlying process of somatic evolution, which follows a Darwinian logic, i.e., diversification of heritable phenotypes provides a substrate for natural selection, resulting in the outgrowth of the most fit subpopulations. Although somatic evolution can tap into multiple sources of diversification, it is assumed to lack access to (para)sexual recombination – a key diversification mechanism throughout all strata of life. Based on observations of spontaneous fusions involving cancer cells, reported genetic instability of polypoid cells, and precedence of fusion-mediated parasexual recombination in fungi, we asked whether cell fusions could serve as a source of parasexual recombination in cancer cell populations. Using differentially labelled tumor cells, we found evidence of low-frequency, spontaneous cell fusions between carcinoma cells in multiple cell line models of breast cancer both in vitro and in vivo. While some hybrids remained polyploid, many displayed partial ploidy reduction, generating diverse progeny with heterogeneous inheritance of parental alleles, indicative of partial recombination. Hybrid cells also displayed elevated levels of phenotypic plasticity, which may further amplify the impact of cell fusions on the diversification of phenotypic traits. Using mathematical modeling, we demonstrated that the observed rates of spontaneous somatic cell fusions may enable populations of tumor cells to amplify clonal heterogeneity, thus facilitating the exploration of larger areas of the adaptive landscape, relative to strictly asexual populations, which may substantially accelerate a tumor’s ability to adapt to new selective pressures.
2020-10-21 | GSE159679 | GEO
Project description:Spontaneous Cell Fusions as a Mechanism of Parasexual Recombination in Tumor Cell Populations.
| PRJNA662960 | ENA
Project description:Spontaneous Cell Fusions as a Mechanism of Parasexual Recombination in Tumor Cell Populations. [2]
| PRJNA670185 | ENA
Project description:Spontaneous Cell Fusions as a Mechanism of Parasexual Recombination in Tumor Cell Populations. [1]
| PRJNA670184 | ENA
Project description:This SuperSeries is composed of the SubSeries listed below.
2020-10-21 | GSE159681 | GEO
Project description:The Saccharomyces cerevisae RAD3 gene is homolog of human XPD, an essential gene encoding a DNA helicase of the TFIIH complex involved in both nucleotide excision repair (NER) and transcription. Mutant alleles of RAD3 have been identified (rad3-101 and rad3-102) that have partial defects in DNA repair associated with a strong hyper-recombination (hyper-Rec) phenotype. Previous studies showed that the hyper-Rec phenotype associated with rad3-101 and rad3-102 can be explained as a consequence of persistent single-stranded DNA gaps that are converted to recombinogenic double-strand breaks (DSBs) by replication. We have further characterized these events using a system in which the reciprocal products of mitotic recombination between homologs are recovered as red and white sectored colonies. Both rad3-101 and rad3-102 elevate the frequency of sectored colonies about 100-fold. Subsequent mapping of these events shows that three-quarters of crossovers between homologs induced in hyper-Rec rad3 mutants reflect DSBs formed in at the same positions in both sister chromatids (double sister-chromatid breaks, DSCBs). The remainder reflects DSBs formed in single chromatids (single chromatid breaks, SCBs). The ratio of DSCBs to SCBs is similar to that observed for spontaneous recombination events in wild-type cells. In addition to examining crossovers on chromosome V, we mapped 216 unselected genomic alterations throughout the genome including crossovers, gene conversions, deletions, and duplications. We found a significant association between the location of these recombination events and regions with elevated gamma-H2AX. In addition, there was a hotspot for deletions and duplications at the IMA2 and HXT11 genes near the left end of chromosome XV. A comparison of these data with our previous analysis of spontaneous mitotic recombination events suggests that a sub-set of spontaneous events in wild-type cells may be initiated by incomplete NER reactions, and that DSCBs, which cannot be repaired by sister-chromatid recombination, are a major source of mitotic recombination between homologous chromosomes.
2015-12-30 | GSE76395 | GEO
Project description:Allogenic hematopoietic cell transplantation (alloHCT) is a well-established curative modality for adults with high-risk ALL; yet large data describing alloHCT outcomes in Philadelphia (Ph)-like ALL is lacking. We retrospectively analyzed archived DNA samples from consecutive adults with B-cell Ph-negative ALL who underwent alloHCT in complete remission (CR) (n= 127) at our center between 2006 and 2020. Identification of fusions associated with Ph-like were performed using accumulative results from RNAseq, conventional cytogenetics, FISH, and whole genome array studies. Fusions associated with Ph-like were detected in 56 (44%) patients, of whom 38 were carrying CRLF2r; and the rest (n=18) were non-CRLF2r. Compared to other non-Ph-like (n=71), patients with fusions associated with Ph-like ALL were more frequently Hispanic (P=0.008), less frequently carried high-risk cytogenetics (P<0.001), and more likely to receive blinatumomab prior to HCT (P=0.019). With the median follow-up of 3.5 years, patients with Ph-like ALL fusions had comparable post-transplant outcomes compared to other B-cell ALL: 3-year relapse-free survival (RFS) [41% vs. 44%, P=0.36], overall survival (OS) [51% vs. 50%, P=0.59] and relapse [37% vs. 31%, P=0.47]. In multivariable analysis, age (P= 0.023), disease status at the time of transplant (P<0.001), and donor type (P=0.015) influenced OS. RFS (primary endpoint) was significantly influenced by disease status (P<0.001) and conditioning regimen intensity (P=0.014). Relapse rate was associated with disease status (P=0.028) and conditioning regimen intensity (P=0.028). In conclusion, our data suggest that alloHCT consolidation results in similarly favorable survival outcomes in adult patients with Ph-like fusions and other high-risk B-cell ALL.
2022-08-01 | E-MTAB-11954 | biostudies-arrayexpress
Project description:Eukaryotic genomes typically consist of multiple (linear) chromosomes that are replicated from multiple origins. Several hypothetical scenarios have been proposed to account for the evolution of multi-origin/multi-chromosome genomes, which are encountered in modern eukaryotes and archaea. Here we report an example of the generation of a new chromosome in the halophilic archaeon Haloferax volcanii through one of these scenarios: acquisition of new replication origins and splitting of an ancestral chromosome into two replication-competent chromosomes. The multi-origin main chromosome has split into two genome elements via homologous recombination. The newly generated elements possess all the features of bona fide chromosomes. To our knowledge, the spontaneous generation of a new chromosome in prokaryotes without horizontal gene transfer has not been reported previously.
2018-04-17 | GSE108201 | GEO