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Expression data by G-quadruplex (G4) forming oligonucleotides transfection in 3D culture.

ABSTRACT: 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. Six samples are G4 oligo-transfected cells (PC-3/(uuaggg)^4, PC-3/AS1411, HBC4/(uuaggg)^4, HBC4/AS1411, MKN74/(uuaggg)^4 and MKN74/AS1411), and the other six samples are control oligo-transfected cells.

ORGANISM(S): Homo sapiens

SUBMITTER: kyotaro HIRASHIMA

PROVIDER: E-GEOD-56239 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Expression data by telomere elongation in xenograft.

Project description: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 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. Four samples are telomere-elongated cells (PC3/LhTERTL, PC3/LhTERTL/cre, HBC4/hTERT and MKN74/hTERT), and the other four samples are control cell lines.

2015-02-05 | E-GEOD-56177 | biostudies-arrayexpress

Expression data by G-quadruplex (G4) forming oligonucleotides transfection in 3D culture.

Project description: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.

2015-02-05 | GSE56239 | GEO

Expression data by telomere elongation in xenograft.

2015-02-05 | GSE56177 | GEO

Expression data by telomere elongation in vivo (xenograft)

Project description:Limitless 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. Two cell lines are telomere-elongated cells, both in the presence and absence of the exogenous hTERT. The other two lines are control PC-3 cell lines. We extracted RNA from four independent xenograft tumors per original cell line.

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Project description:Alternative Lengthening of Telomeres (ALT) cancer cells are a subset of cancers that depend on the homologous recombination mechanism to extend their telomere length independent of telomerase. ALT cells contain elevated levels of the telomeric-repeat containing long noncoding RNA (TERRA), which is an RNA transcribed by RNA polymerase II and can form RNA:DNA (R-loops) hybrids at telomeres. Lines of evidence have shown that the formation of R-loops at telomeres could be one of the mechanisms to trigger DNA repair to lengthen telomeres. We perform iDRiP-MS, a method to capture specific RNA interacting protein by UV light crosslinking using antisense probe capture (Chu et al., 2017a; Minajigi et al., 2015), to explore the TERRA interactomes in human ALT cancer cell. Our TERRA interactome data reveals that TERRA interacts with an extensive subset of DNA repair proteins in ALT cells including the endonuclease XPF, suggesting that TERRA R-loops activate DDR via XPF to promote homologous recombination and telomere replication to drive ALT.

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Expression data by telomere elongation

Project description:Limitless 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. Two samples are telomere-elongated cells, both in the presence and absence of the exogenous hTERT. The other two samples are control cell lines.

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2020-01-31 | PXD016772 | Pride

RAD51AP1 regulates ALT-HDR through chromatin-directed homeostasis of TERRA

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m6A RNA modification of TERRA lncRNA drives R-Loop formation and is required for telomere maintenance in ALT tumors [III]

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