Telomere erosion causes cell mortality, suggesting that longer telomeres allow greater number of cell division. In telomerase-positive human cancer cells, however, telomeres are often kept shorter than the surrounding normal tissues. Recently, we have shown that telomere elongation in cancer cells represses innate immune genes and promotes their differentiation in vivo. This implies that short telomeres contribute to cancer malignancy, but it is unclear how such genetic repression is caused by long telomeres. Here we report that telomeric repeat-containing RNA (TERRA) induces genome-wide alteration of gene expression in telomere-elongated cancer cells in vivo. Using three different cell lines, we found that G4 forming oligonucleotide repressed innate immune genes in vivo 3D culture conditions. Most of the suppressed genes belonged to innate immune system categories and were upregulated in various cancers. We propose that TERRA G4 counteracts cancer malignancy through suppression of innate immune genes.
Telomeric repeat-containing RNA/G-quadruplex-forming sequences cause genome-wide alteration of gene expression in human cancer cells in vivo.
Cell line, Treatment
View SamplesTelomere erosion causes cell mortality, suggesting that longer telomeres allow greater number of cell division. In telomerase-positive human cancer cells, however, telomeres are often kept shorter than the surrounding normal tissues. Recently, we have shown that telomere elongation in cancer cells represses innate immune genes and promotes their differentiation in vivo. This implies that short telomeres contribute to cancer malignancy, but it is unclear how such genetic repression is caused by long telomeres. Here we report that telomeric repeat-containing RNA (TERRA) induces genome-wide alteration of gene expression in telomere-elongated cancer cells in vivo. Using three different cell lines, we found that telomere elongation upregulates TERRA and downregulates innate immune genes in vivo xenograft tumors. Most of the suppressed genes belonged to innate immune system categories and were upregulated in various cancers. We propose that TERRA G4 counteracts cancer malignancy through suppression of innate immune genes.
Telomeric repeat-containing RNA/G-quadruplex-forming sequences cause genome-wide alteration of gene expression in human cancer cells in vivo.
Disease, Cell line
View SamplesLimitless reproductive potential is one of the hallmarks of cancer cells1. This ability is accomplished by maintaining telomeres, which erosion otherwise causes cellular senescence or death. Human cancer cells often maintain shorter telomeres than do cells in surrounding normal tissues2-5. While most cancer cells activate telomerase, which can elongate telomeres6, it remains elusive why cancer cells keep telomeres short. Here we show that forced elongation of telomeres in cancer cells promotes their differentiation in a tumor microenvironment in vivo. We elongated telomeres of human prostate cancer PC-3 cells, which possess short telomeres7, by enhancing their telomerase activity. The resulting cells with long telomeres retain an ability to form tumors in a mouse xenograft model. Strikingly, these tumors exhibit many duct-like structures and reduced N-cadherin expression, reminiscent of well-differentiated adenocarcinoma. These phenotypic changes are caused by telomere elongation per se but not enhanced telomerase activity. Gene expression profiling revealed that telomere elongation correlates with inhibition of cell-cycle processes. Together, our results suggest a functional contribution of short telomeres to tumor malignancy by regulating cancer cell differentiation.
Telomere length influences cancer cell differentiation in vivo.
Cell line
View SamplesLimitless reproductive potential is one of the hallmarks of cancer cells1. This ability is accomplished by maintaining telomeres, which erosion otherwise causes cellular senescence or death. Human cancer cells often maintain shorter telomeres than do cells in surrounding normal tissues2-5. While most cancer cells activate telomerase, which can elongate telomeres6, it remains elusive why cancer cells keep telomeres short. Here we show that forced elongation of telomeres in cancer cells promotes their differentiation in a tumor microenvironment in vivo. We elongated telomeres of human prostate cancer PC-3 cells, which possess short telomeres7, by enhancing their telomerase activity. The resulting cells with long telomeres retain an ability to form tumors in a mouse xenograft model. Strikingly, these tumors exhibit many duct-like structures and reduced N-cadherin expression, reminiscent of well-differentiated adenocarcinoma. These phenotypic changes are caused by telomere elongation per se but not enhanced telomerase activity. Gene expression profiling revealed that telomere elongation correlates with inhibition of cell-cycle processes. Together, our results suggest a functional contribution of short telomeres to tumor malignancy by regulating cancer cell differentiation.
Telomere length influences cancer cell differentiation in vivo.
Cell line
View SamplesDeregulated retinal angiogenesis directly cause vision loss in many ocular diseases, such as diabetic retinopathy and retinopathy of prematurity. To identify endothelial-specific genes expressed in angiogenic retinal vessels, we purified genetically labeled endothelial cells from Tie2-GFP transgenic mice and performed gene expression profiling using DNA microarray. To find out genes associated with angiogenesis, comparisons of microarray data were carried out between GFP-negative non-endothelial retinal cells and GFP-positive retinal endothelial cells in angiogenic P8 retina.
Sema3E-PlexinD1 signaling selectively suppresses disoriented angiogenesis in ischemic retinopathy in mice.
Specimen part
View SamplesExpression data from mice exposed to intermittent hypoxia and mice reared for 12 months. We used microarrays to analyze the transcriptome of hippocampus from mice exposed to intermittent hypoxia or aged mice.
Treatment of intermittent hypoxia increases phosphorylated tau in the hippocampus via biological processes common to aging.
Specimen part, Treatment
View SamplesPartial induced pluripotent cells (iPSCs) are cell lines strayed from normal route from somatic cells to iPSCs and are immortalized. Mouse partial iPSCs are able to convert to real iPSCs by the exposure to 2i condition using MAPK and GSK3? inhibitors. However, the molecular mechanisms of this conversion are totally not known. Our piggyback vector mediated genome-wide screen revealed that Cnot2, one of core components of Ccr4-Not complex participates in this conversion. Subsequent analyses revealed other core components, i.e., Cnot1 and Cnot3 and Trim28 which is known to extensively share genomic binding sites with Cnot3 contribute to this conversion as well. Our bioinformatics analyses indicate that the major role of these factors in the conversion is the down-regulation of developmental genes in partial iPSCs.
Identification of Ccr4-not complex components as regulators of transition from partial to genuine induced pluripotent stem cells.
Sex, Specimen part
View SamplesWerner syndrome (WS) is a premature aging disorder characterized by chromosomal instability and cancer predisposition. Mutations in WRN are responsible for the disease and cause telomere dysfunction, resulting in accelerated aging. In the present study, we describe the effects of long-term culture on WS iPSCs, which acquired and maintained infinite proliferative potential for self-renewal over 2 years. After long-term cultures, WS iPSCs exhibited stable undifferentiated states and differentiation capacity, and premature upregulation of senescence-associated genes in WS cells was completely suppressed in WS iPSCs despite WRN deficiency.
Reprogramming suppresses premature senescence phenotypes of Werner syndrome cells and maintains chromosomal stability over long-term culture.
Specimen part
View SamplesLow-intensity pulsed ultrasound (LIPUS) has been applied as a therapeutic adjunct to promote fracture healing. However, the detailed molecular mechanisms by which LIPUS promotes bone fracture healing have not yet been fully elucidated.
Genetic response to low‑intensity ultrasound on mouse ST2 bone marrow stromal cells.
Specimen part
View SamplesOncolytic viruses exploit common molecular changes in cancer cells, which are not present in normal cells, to target and kill cancer cells. Ras transformation and defects in type I interferon (IFN)-mediated antiviral responses are known to be the major mechanisms underlying viral oncolysis. Previously, we demonstrated that oncogenic RAS/Mitogen-activated protein kinase kinase (Ras/MEK) activation suppresses the transcription of many IFN-inducible genes in human cancer cells, suggesting that Ras transformation underlies type I IFN defects in cancer cells. Here, we investigated how Ras/MEK downregulates IFN-induced transcription. By conducting promoter deletion analysis of IFN-inducible genes, namely guanylate-binding protein 2 and IFN gamma inducible protein 47 (Ifi47), we identified the IFN regulatory factor 1 (IRF1) binding site as the promoter region responsible for the regulation of transcription by MEK. MEK inhibition promoted transcription of the IFN-inducible genes in wild type mouse embryonic fibroblasts (MEFs), but not in IRF1/ MEFs, showing that IRF1 is involved in MEK-mediated downregulation of IFN-inducible genes. Furthermore, IRF1 protein expression was lower in RasV12 cells compared with vector control NIH3T3 cells, but was restored to equivalent levels by inhibition of MEK. Similarly, the restoration of IRF1 expression by MEK inhibition was observed in human cancer cells. IRF1 re-expression in human cancer cells caused cells to become resistant to infection by the oncolytic vesicular stomatitis virus strain. Together, this work demonstrates that Ras/MEK activation in cancer cells downregulates transcription of IFN-inducible genes by targeting IRF1 expression, resulting in increased susceptibility to viral oncolysis.
Oncogenic Ras inhibits IRF1 to promote viral oncolysis.
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