Dataset Information

A RNA-seq-based gene expression profiling of radiation-induced tumorigenic mammary epithelial cells

ABSTRACT: To understand tumorigenesis and cancer progression of mammary epithelium, we established a cell model combining over-expression of human telomerase reverse transcriptase gene (hTERT) and heavy-ion radiation from normal human mammary epithelial cells. We subsequently used RNA-seq method to acquire their transcriptomes from two characteristic cell lines, an immortal epithelial cell line (I_hMEC) and a tumorigenic epithelial cell line (T_hMEC), and to look for differentially expressed genes (DEGs) between immortalization and tumorigenicity. We identified 7,053 DEGs, of which 84 were not only highly expressed but also significantly regulated. We found that house-keeping (HK) genes and tissue-specific (TS) genes were regulated differently during tumorigenesis; HK genes tend to be activated but TS genes tend to be repressed. We looked into three important pathways in cancer development: p53 signaling, cell cycle, and apoptosis. Although both immortal and tumorigenic cells have infinite potential to replicate and can escape apoptosis, a great number of genes exhibited different modulation pattern between the two processes. We also found that a significant number of DEGs were involved in epigenetic modification of chromatins. In conclusion, these findings may provide novel biomarkers in studying tumorigenicity and further our understanding of cellular mechanism(s) in the transition from immortal to tumorigenic processes.

ORGANISM(S): Homo sapiens

PROVIDER: GSE31310 | GEO | 2013/12/09

SECONDARY ACCESSION(S): PRJNA146017

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:- Gene expression changes linked to two step immortalization of human mammary epithelial cells (HMEC). - A lincRNA, MORT, associated with the mortal state, was identified - MORT is silenced by DNA methylation in immortal mammary epithelial cells Abstract: Immortality is an essential characteristic of human carcinoma cells. We recently developed an efficient, reproducible method that immortalizes human mammary epithelial cells (HMEC) in the absence of gross genomic changes by targeting two critical senescence barriers. Consistent transcriptomic changes associated with immortality were identified using microarray analysis of isogenic normal finite pre-stasis, abnormal finite post-stasis, and immortal HMECs from four individuals. 277 genes consistently changed in cells that transitioned from post-stasis to immortal. Gene ontology analysis of affected genes revealed biological processes significantly altered in the immortalization process. These immortalization-associated changes showed striking similarity to the gene expression changes seen in The Cancer Genome Atlas (TCGA) clinical breast cancer data. The most dramatic change in gene expression seen during the immortalization step was the down-regulation of an unnamed, incompletely annotated transcript that we called MORT, for mortality, since its expression was closely associated with the mortal, finite lifespan phenotype. We show here that MORT (ZNF667-AS1) is expressed in all normal finite lifespan human cells examined to date and is lost in immortalized HMEC. MORT gene silencing at the mortal/immortal boundary was due to DNA hypermethylation of its CpG island promoter. This epigenetic silencing is also seen in human breast cancer cell lines and in a majority of human breast tumor tissues. The functional importance of DNA hypermethylation in MORT gene silencing is supported by the ability of 5-aza-2’-deoxycytidine to reactivate MORT expression. Analysis of TCGA data revealed deregulation of MORT expression due to DNA hypermethylation in 15 out of the 17 most common human cancers. The epigenetic silencing of MORT in a large majority of the common human cancers suggests a potential fundamental role in cellular immortalization during human carcinogenesis.

Project description:Background: In both Turner syndrome (TS) and Klinefelter syndrome (KS) copy number aberrations of the X chromosome lead to various developmental symptoms. To date there has not been a comprehensive and directly comparative analysis of TS vs. KS regarding the changes on the molecular level Methods: We analyzed gene expression patterns with RNA-Seq and DNA methylation patterns with the CpGiant assay in lymphocytes, and chromatin conformation with in situ Hi-C in lymphoblastoid cell lines, from TS and KS patients together with their same gender controls. Results: In TS, differentially expressed escape genes were downregulated but differentially expressed inactive genes were upregulated. In KS, differentially expressed escape genes were upregulated while inactive genes appeared unchanged. Interestingly, 81 differentially expressed genes (DEGs) were associated with both TS and KS, and uniformly displayed expression changes into opposite directions. DEGs on the X chromosome and the autosomes were coexpressed in both TS and KS, indicating that there are molecular ripple effects of the changes in X chromosome dosage that extend to autosomes. Four potentially candidate genes (RPS4X, SEPT6, NKRF and CX0rf57) for KS were identified on Xq. Broad hypomethylation of the X chromosome is observed in TS whereas hypermethylation of chromosome X is present in KS. Only promoters of inactive genes were differentially methylated in both TS and KS while escape genes remained unchanged. The intrachromosomal contact map of the X chromosome in TS was partitioned into two superdomains and exhibited the structure of an active X chromosome. Conclusions: Components of the molecular basis of TS and KS were identified on the levels of the transcriptome and the epigenome, with candidate central genes on Xp for TS and on Xq for KS. The discovery of shared DEGs indicates the existence of common molecular mechanisms for gene regulation in TS and KS that are transmitting the gene dosage changes to the transcriptome.

Dataset Information

A RNA-seq-based gene expression profiling of radiation-induced tumorigenic mammary epithelial cells

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets