The SWI/SNF-family chromatin remodeling protein ATRX is a tumor suppressor in sarcomas, gliomas and other malignancies. Its loss of function facilitates the alternative lengthening of telomeres (ALT) pathway in tumor cells, while it also affects Polycomb repressive complex 2 (PRC2) silencing of its target genes. To further define the role of inactivating ATRX mutations in carcinogenesis, we knocked out atrx in our previously published p53/nf1-deficient zebrafish line that develops malignant peripheral nerve sheath tumors and gliomas. Complete inactivation of atrx using CRISPR-cas9 was lethal in developing fish and resulted in an alpha-thalassemia-like phenotype including reduced alpha-globin expression. In p53/nf1-deficient zebrafish neither peripheral nerve sheath tumors nor gliomas showed accelerated onset in atrx+/- fish, but these fish developed various tumors that were not observed in their atrx+/+ siblings, including epithelioid sarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma and rare types of carcinoma. Most of these cancer types are included in the AACR Genie database of human tumors associated with mutant ATRX, indicating that our zebrafish model reliably reflects a role for ATRX-loss in the early pathogenesis of these types of human cancers. RNA-seq of p53/nf1- and p53/nf1/atrx-deficient tumors revealed that down-regulation of telomerase accompanied ALT-mediated lengthening of the telomeres in atrx-mutant samples. Moreover, inactivating mutations in atrx disturbed PRC2-target gene silencing, indicating a connection between ATRX loss and PRC2 dysfunction in cancer development. Overall design: Gene expression values were derived from paired end RNA-Seq data that compared zebrafish samples from p53/nf1/atrx-deficient tumors to samples from atrx-wildtype controls (3 vs. 3 samples).
Loss of atrx cooperates with p53-deficiency to promote the development of sarcomas and other malignancies.
Background & Aims: Chronic hepatitis C virus (HCV) infection is complicated by hepatic fibrosis. Hypothesizing that fibrogenic signals may originate in cells susceptible to HCV infection, gene expression of hepatocytes was analyzed from persons with chronic HCV at different stages of liver fibrosis. Methods: HCV-infected subjects with significant liver fibrosis (Ishak fibrosis 3) were matched for age, race, and gender to subjects with minimal fibrosis (Ishak fibrosis 0-1). RNA from portal tracts and hepatic parenchyma was isolated from biopsies by laser capture and transcriptome profiling was performed using hybridization arrays. Results: Portal tracts from both groups were enriched for immune related genes when compared to hepatocytes but high fibrosis subjects showed a loss of this enrichment. Hepatocytes from persons with high fibrosis were depleted for genes involved in small molecule and drug metabolism, especially butyrylcholinesterase (BCHE), a gene involved in the metabolism of drugs of abuse. Differential expression of BCHE was validated in the same tissues using qPCR. Cross-sectional and longitudinal testing in an expanded cohort of HCV-infected individuals showed that serum BCHE activity decreased in advance of progression to fibrosis. Conclusion: Chronic HCV infection is associated with a loss of hepatocyte metabolic function, decreased enrichment of immune-related genes in portal tracts and downregulation of BCHE in hepatocytes. Our results indicate that BCHE may be involved in the progression of fibrosis during HCV infection among injection drug users and may serve as a useful marker for fibrosis progression.
Laser captured hepatocytes show association of butyrylcholinesterase gene loss and fibrosis progression in hepatitis C-infected drug users.
Sex, Age, RaceView Samples
NOTCH proteins regulate signaling pathways involved in cellular differentiation, proliferation and death. Overactive Notch signaling as been observed in numerous cancers and has been extensively studied in the context of T-cell acute lymphoblastic leukemia (T-ALL) where more than 50% of pateints harbour mutant NOTCH1. Small molecule modulators of these proteins would be important for understanding the role of NOTCH proteins in malignant and normal biological processes.
Direct inhibition of the NOTCH transcription factor complex.
Specimen part, Cell lineView Samples
Expression of a constitutively active Notch-1 intracellular domain (NICD) in MCF-10A cells was found to induce two distinct types of 3D structures: large, hyperproliferative structures and small, growth-arrested structures with reduced cell-to-matrix adhesion. These heterogeneous phenotypes reflect differences in Notch pathway activation levels. High Notch activity caused loss of cell adhesion and inhibition of proliferation, whereas low Notch activity maintained matrix adhesion and provoked a strong hyperproliferative response. In order to gain insight into the dosage-dependent transcriptional events triggered by Notch1 activation, gene expression profiles induced 48 hours after infection of MCF-10A cells with retroviral vectors expressing full-length Notch-1, L1601P+P, or NICD were compared. Full-length Notch-1 induced the weakest effect, L1601P+P induced an intermediate effect and NICD induced the strongest effect. Results provide insight into the dichotomous activites of Notch during development and tumorigenesis.
Dose-dependent induction of distinct phenotypic responses to Notch pathway activation in mammary epithelial cells.
Cell lineView Samples
Platelets are a rich source of many cytokines and chemokines including transforming growth factor -1 (TGF1). TGF1 is required to convert conventional CD4+ T (Tconv) cells into induced regulatory T (iTreg) cells that express the transcription factor Foxp3. To explore whether other platelet contents will affect the properties of TGF induced Treg cell, we used platelet lysate that contain many other cytokines and chemokines besides TGF1 (pltTGF) to induce Foxp3 expression (pltTGFb-iTreg) from conventional CD4+ T (Tconv) cells. We used purified TGF1 to induce Treg (purTGF-iTreg) cells as a control. Gene expression profiles in iTreg cells were analyzed by microarray asay.
TGF-β1 along with other platelet contents augments Treg cells to suppress anti-FVIII immune responses in hemophilia A mice.
No sample metadata fieldsView Samples
Despite initial and often dramatic responses of epidermal growth factor receptor (EGFR)-addicted lung tumors to the EGFR-specific tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib, nearly all develop resistance and relapse. To explore novel mechanisms mediating acquired resistance, we employed non-small-cell lung cancer (NSCLC) cell lines bearing activating mutations in EGFR and rendered them resistant to EGFR-specific TKIs through chronic adaptation in tissue culture. In addition to previously observed resistance mechanisms including EGFR-T790M ''gate-keeper'' mutations and MET amplification, a subset of the seven chronically adapted NSCLC cell lines including HCC4006, HCC2279 and H1650 cells exhibited marked induction of fibroblast growth factor (FGF) 2 and FGF receptor 1 (FGFR1) mRNA and protein. Also, adaptation to EGFR-specific TKIs was accompanied by an epithelial to mesenchymal transition (EMT) as assessed by changes in CDH1, VIM, ZEB1 and ZEB2 expression and altered growth properties in Matrigel. In adapted cell lines exhibiting increased FGF2 and FGFR1 expression, measures of growth and signaling, but not EMT, were blocked by FGFR-specific TKIs, an FGF-ligand trap and FGFR1 silencing with RNAi. In parental HCC4006 cells, cell growth was strongly inhibited by gefitinib, although drug-resistant clones progress within 10 days. Combined treatment with gefitinib and AZD4547, an FGFR-specific TKI, prevented the outgrowth of drug-resistant clones. Thus, induction of FGF2 and FGFR1 following chronic adaptation to EGFR-specific TKIs provides a novel autocrine receptor tyrosine kinase-driven bypass pathway in a subset of lung cancer cell lines that are initially sensitive to EGFR-specific TKIs. The findings support FGFR-specific TKIs as potentially valuable additions to existing targeted therapeutic strategies with EGFR-specific TKIs to prevent or delay acquired resistance in EGFR-driven NSCLC. Overall design: Examination of mRNA levels in DMSO and gefitinib-resistant cultures of HCC4006 and HCC827. Each group has two replicates.
A mechanism of resistance to gefitinib mediated by cellular reprogramming and the acquisition of an FGF2-FGFR1 autocrine growth loop.
Specimen part, Cell line, Treatment, SubjectView Samples
Although transcriptional programs associated with T-cell specification and commitment have been described, the functional hierarchy and the roles of key regulators in structuring/ orchestrating these programs remain unclear. Activation of Notch signaling in uncommitted precursors by the thymic stroma initiates the T-cell differentiation program. One regulator first induced in these precursors is the DNA binding protein Tcf-1, a T-cell specific mediator of Wnt signaling. Yet the specific contribution of Tcf-1 to early T-cell development and the signals inducing it in these cells remain unclear. Here we assign functional significance to Tcf-1 as a gatekeeper of T-cell fate. We show that Tcf-1 is directly activated by Notch signals. Tcf-1 is required at the earliest phase of Tcell determination for progression beyond the early thymic progenitor (ETP) stage. The global expression profile of Tcf-1 deficient progenitors indicates that basic processes of DNA metabolism are downregulated in its absence and the blocked T-cell progenitors become abortive and die by apoptosis. Our data thus add an important functional relationship to the roadmap of T-cell development.
T-cell factor 1 is a gatekeeper for T-cell specification in response to Notch signaling.
Specimen partView Samples
Dietary polyunsaturated fatty acids (PUFA) are suggested to modulate immune function, but the effects of dietary fatty acids composition on gene expression patterns in immune organs have not been fully characterized. In the current study we investigated how dietary fatty acids composition affects the total transcriptome profile, and especially, immune related genes, in bone marrow cells (BMC) and spleen (SPL). Four tissues with metabolic function, skeletal muscle (SKM), white adipose tissue (WAT), brown adipose tissue (BAT), and liver (LIV), were investigated as a comparison. Following 8 weeks on low fat diet (LFD), high fat diet (HFD) rich in saturated fatty acids (HFD-S), or HFD rich in PUFA (HFD-P), tissue transcriptomics were analyzed by microarray and metabolic health assessed by fasting blood glucose level, HOMA-IR index, oral glucose tolerance test as well as quantification of crown-like structures in WAT. Interestingly, SKM and BMC were relatively inert to the diets, whereas the two adipose tissues (WAT and BAT) were mainly affected by HFD per se (both HFD-S and HFD-P). In particular, WAT gene expression was driven closer to that of the immune organs SPL and BMC by HFDs. Remarkably, the spleen, showed a major response to HFD-P, but not to HFD-S, whereas the LIV exhibited different responses to both of the HFDs. Further, HFD-P corrected the metabolic phenotype induced by HFD-S. Hence, the quantity and composition of dietary fatty acids affected the transcriptome in a distinct manner. Especially, PUFA prompted a specific regulation of immune related genes in the spleen. Thus, PUFA can regulate immune function by influencing gene expression.
Six Tissue Transcriptomics Reveals Specific Immune Suppression in Spleen by Dietary Polyunsaturated Fatty Acids.
Sex, Specimen partView Samples
The targeting of oncogenic ‘driver’ kinases with small molecule inhibitors has proven to be a highly effective therapeutic strategy in selected non-small cell lung cancer (NSCLC) patients. However, acquired resistance to targeted therapies invariably arises and is a major limitation to patient care. ROS1 fusion proteins are a recently described class of oncogenic driver, and NSCLC patients that express these fusions generally respond well to ROS1-targeted therapy. In this study, we sought to determine mechanisms of acquired resistance to ROS1 inhibition. To accomplish this, we generated a ROS1 inhibition-resistant derivative of the initially sensitive NSCLC cell line HCC78.
Resistance to ROS1 inhibition mediated by EGFR pathway activation in non-small cell lung cancer.
No sample metadata fieldsView Samples
Notch is normally activated by cleavage and nuclear translocation of its intracellular domain (ICN1), which turns on downstream target genes. Human T cell acute lymphoblastic leukemia (T-ALL), an aggressive immature T cell malignancy, is associated with Notch 1 gain-of-function mutations in more than 50% of the cases. Efforts to date to identify direct Notch1 targets have been confounded by the lack of a method to turn Notch1 on in a controlled fashion in T-ALL cells that are poised to respond to Notch signals. Of note, because Notch signaling activates transcriptional repressors that feedback to dampen the expression of many target genes (a process referred to as incoherent logic), it is likely that many direct targets are missed in Notch off analyses, which are further complicated by an inability to identify direct targets in a clear-cut fashion. We have overcome this limitation by developing a GSI washout method that results in the rapid translocation of activated Notch1 to the nucleus. We intend to use this method to study the assembly and loading of transcriptional complexes onto downstream targets, the kinetics of target activation. To date, our efforts have been devoted to comparing the gene expression signature of Notch-on and Notch-off in the human T-ALL cell line CUTLL. In addition to previously identified Notch1 target genes, we have also identified a series of novel genes upregulated by GSI washout in the presence of cycloheximide, suggesting that they are likely to be direct targets.
Genome-wide analysis reveals conserved and divergent features of Notch1/RBPJ binding in human and murine T-lymphoblastic leukemia cells.
Cell lineView Samples