G9a and GLP are conserved protein methyltransferases that play key roles during mammalian development through mono- and dimethylation of histone H3 Lys 9 (H3K9me1/2), modifications associated with ...transcriptional repression. During embryogenesis, large H3K9me2 chromatin territories arise that have been proposed to reinforce lineage choice by affecting high-order chromatin structure. Here we report that in adult human hematopoietic stem and progenitor cells (HSPCs), H3K9me2 chromatin territories are absent in primitive cells and are formed de novo during lineage commitment. In committed HSPCs, G9a/GLP activity nucleates H3K9me2 marks at CpG islands and other genomic sites within genic regions, which then spread across most genic regions during differentiation. Immunofluorescence assays revealed the emergence of H3K9me2 nuclear speckles in committed HSPCs, consistent with progressive marking. Moreover, gene expression analysis indicated that G9a/GLP activity suppresses promiscuous transcription of lineage-affiliated genes and certain gene clusters, suggestive of regulation of HSPC chromatin structure. Remarkably, HSPCs continuously treated with UNC0638, a G9a/GLP small molecular inhibitor, better retain stem cell-like phenotypes and function during in vitro expansion. These results suggest that G9a/GLP activity promotes progressive H3K9me2 patterning during HSPC lineage specification and that its inhibition delays HSPC lineage commitment. They also inform clinical manipulation of donor-derived HSPCs.
Recently, classification-based preselection (CPS) strategy for evolutionary multiobjective optimization has been found to be very effective and efficient for solving complicated multiobjective ...optimization problems (MOPs). However, this strategy can only classify the candidate solutions into different categories, but it is difficult to find out which one is the best. In order to overcome this shortcoming, we propose a surrogate individual selection mechanism for multiobjective evolutionary algorithm based on decomposition. In this mechanism, we get the best one from candidate solution set by surrogate model, which mitigates the risk of using CPS strategy. Furthermore, we generate candidate solution set through a new offspring generation strategy, which can improve the quality of the candidate solutions. Based on typical multiobjective evolutionary algorithm MOEA/D, we design a new algorithm framework, called MOEA/D-SISM, through integrating the proposed surrogate individual selection mechanism. We compare MOEA/D-SISM with other state-of-the-art multiobjective evolutionary algorithms (MOEAs), and experimental results show that our proposed algorithm obtains the best performance.
Despite progress in developing defined conditions for human embryonic stem cell (hESC) cultures, little is known about the cell-surface receptors that are activated under conditions supportive of ...hESC self-renewal. A simultaneous interrogation of 42 receptor tyrosine kinases (RTKs) in hESCs following stimulation with mouse embryonic fibroblast (MEF) conditioned medium (CM) revealed rapid and prominent tyrosine phosphorylation of insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R); less prominent tyrosine phosphorylation of epidermal growth factor receptor (EGFR) family members, including ERBB2 and ERBB3; and trace phosphorylation of fibroblast growth factor receptors. Intense IGF1R and IR phosphorylation occurred in the absence of MEF conditioning (NCM) and was attributable to high concentrations of insulin in the proprietary KnockOut Serum Replacer (KSR). Inhibition of IGF1R using a blocking antibody or lentivirus-delivered shRNA reduced hESC self-renewal and promoted differentiation, while disruption of ERBB2 signaling with the selective inhibitor AG825 severely inhibited hESC proliferation and promoted apoptosis. A simple defined medium containing an IGF1 analog, heregulin-1β (a ligand for ERBB2/ERBB3), fibroblast growth factor-2 (FGF2), and activin A supported long-term growth of multiple hESC lines. These studies identify previously unappreciated RTKs that support hESC proliferation and self-renewal, and provide a rationally designed medium for the growth and maintenance of pluripotent hESCs.
In recent years, the multiobjective evolutionary algorithm based on decomposition (MOEA/D) has shown superior performance in solving multiobjective optimization problems (MOPs). In MOEA/D, the ...adaptive replacement strategy (ARS) plays a key role in balancing convergence and diversity. However, existing ARSs do not effectively balance convergence and diversity. To overcome this disadvantage, we propose a mechanism for adapting neighborhood and global replacement. This mechanism determines whether a neighborhood or global replacement strategy should be employed in the search process. Furthermore, we design an offspring generation strategy to generate high-quality solutions. We call this new algorithm framework MOEA/D-ARS. The experimental results suggest that the proposed algorithm performs better than certain state-of-the-art MOEAs.
The Anopheles gambiae 1000 Genomes (Ag1000G) Consortium previously utilized deep sequencing methods to catalogue genetic diversity across African An. gambiae populations. We analyzed the complete ...datasets of 1142 individually sequenced mosquitoes through Microsoft Premonition's Bayesian mixture model based (BMM) metagenomics pipeline. All specimens were confirmed as either An. gambiae sensu stricto (s.s.) or An. coluzzii with a high degree of confidence ( > 98% identity to reference). Homo sapiens DNA was identified in all specimens indicating contamination may have occurred either at the time of specimen collection, preparation and/or sequencing. We found evidence of vertebrate hosts in 162 specimens. 59 specimens contained validated Plasmodium falciparum reads. Human hepatitis B and primate erythroparvovirus-1 viral sequences were identified in fifteen and three mosquito specimens, respectively. 478 of the 1,142 specimens were found to contain bacterial reads and bacteriophage-related contigs were detected in 27 specimens. This analysis demonstrates the capacity of metagenomic approaches to elucidate important vector-host-pathogen interactions of epidemiological significance.
Development of specific immunotherapy for colorectal cancer (CRC) will require identification of antigens selectively or exclusively expressed on CRC cells and strategies to induce and enhance immune ...responses against these antigenic targets. Cancer-testis (C-T) antigens are proving to be excellent targets for immunotherapy of solid tumors such as melanoma, but their clinical utility for treatment of CRC has to date been limited by their infrequent expression in CRC cells. Here we report that the hypomethylating agent 5-aza-2'-deoxycytidine (DAC) induces expression of NY-ESO-1 and other C-T genes in CRC cells both in vitro and in vivo in a dose-dependent manner but has negligible effects on the expression of C-T genes in normal nontransformed cells such as fibroblasts. The induction by DAC of NY-ESO-1 expression in CRC cells persists over 100 days after DAC exposure and is associated with increased levels of NY-ESO-1 protein. CRC cells exposed to DAC at concentrations that can be readily achieved in vivo are rendered susceptible to major histocompatibility complex-restricted recognition by CD8 NY-ESO-1-specific T cells. We also demonstrate that retroviral transduction of polyclonal peripheral blood T cells from a metastatic CRC patient with the T-cell receptor α-chain and β-chain genes encoding a human leukocyte antigen-A2-restricted, NY-ESO-1157-165-specific T-cell receptor can be used to generate both CD8 and CD4 NY-ESO-1157-165-specific T cells that selectively recognize DAC-treated CRC but not nontransformed cells. Collectively, these results suggest that the combination of epigenetic modulation and adoptive transfer of genetically engineered T lymphocytes may enable specific immunotherapy for CRC.
Circulating Tumor DNA Allele Fraction Bredno, Joerg; Venn, Oliver; Chen, Xiaoji ...
The American journal of pathology,
October 2022, 2022-10-00, Letnik:
192, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Current imaging-based cancer screening approaches provide useful but limited prognostic information. Complementary to existing screening tests, cell-free DNA–based multicancer early detection (MCED) ...tests account for cancer biology manifested through circulating tumor allele fraction (cTAF), which could inform prognosis and help assess the cancer's clinical significance. This review discusses the factors affecting circulating tumor DNA (ctDNA) levels and cTAF, and their correlation with the cancer's clinical significance. Furthermore, it discusses the influence of cTAF on MCED test performance, which could help inform prognosis. Clinically significant cancers show higher ctDNA levels quantified by cTAF than indolent phenotype cancers within each stage. This is because more frequent mitosis and cell death combined with increased trafficking of cell-free DNA into circulation leads to greater vascularization and depth of tumor invasion. cTAF has been correlated with biomarkers for cancer aggressiveness and overall survival; cancers with lower cTAF had better survival when compared with cancers as determined by the higher cTAF and Surveillance, Epidemiology, and End Results–based survival for that cancer type at each stage. MCED-detected cancers in case-control studies had comparable survival to Surveillance, Epidemiology, and End Results–based survival at each stage. Because many MCED tests use ctDNA as an analyte, cTAF could provide a common metric to compare performance. The prognostic value of cTAF may allow MCED tests to preferentially detect clinically significant cancers at early stages when outcomes are favorable and this may avoid overdiagnosis.
We recently reported the development of a cell-free DNA (cfDNA) targeted methylation (TM)-based sequencing approach for a multi-cancer early detection (MCED) test that includes cancer signal origin ...prediction. Here, we evaluated the prognostic significance of cancer detection by the MCED test using longitudinal follow-up data.
As part of a Circulating Cell-free Genome Atlas (CCGA) substudy, plasma cfDNA samples were sequenced using a TM approach, and machine learning classifiers predicted cancer status and cancer signal origin. Overall survival (OS) of cancer participants in the first 3 years of follow-up was evaluated in relation to cancer detection by the MCED test and clinical characteristics.
Cancers not detected by the MCED test had significantly better OS (
< 0.0001) than cancers detected, even after accounting for other covariates, including clinical stage and method of clinical diagnosis (i.e., standard-of-care screening or clinical presentation with signs/symptoms). Additionally, cancers not detected by the MCED test had better OS than was expected when data were adjusted for age, stage, and cancer type from the Surveillance, Epidemiology, and End Results (SEER) program. In cancers with current screening options, the MCED test also differentiated more aggressive cancers from less aggressive cancers (
< 0.0001).
Cancer detection by the MCED test was prognostic beyond clinical stage and method of diagnosis. Cancers not detected by the MCED test had better prognosis than cancers detected and SEER-based expected survival. Cancer detection and prognosis may be linked by the underlying biological factor of tumor fraction in cfDNA.
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