Abstract
A genome-wide screen for promoter methylation in lung cancer identifies novel methylation markers for multiple malignancies.
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View SamplesBACKGROUND: Promoter hypermethylation coupled with loss of heterozygosity at the same locus results in loss of gene function in many tumor cells. The "rules" governing which genes are methylated during the pathogenesis of individual cancers, how specific methylation profiles are initially established, or what determines tumor type-specific methylation are unknown. However, DNA methylation markers that are highly specific and sensitive for common tumors would be useful for the early detection of cancer, and those required for the malignant phenotype would identify pathways important as therapeutic targets. METHODS AND FINDINGS: In an effort to identify new cancer-specific methylation markers, we employed a high-throughput global expression profiling approach in lung cancer cells. We identified 132 genes that have 5' CpG islands, are induced from undetectable levels by 5-aza-2'-deoxycytidine in multiple non-small cell lung cancer cell lines, and are expressed in immortalized human bronchial epithelial cells. As expected, these genes were also expressed in normal lung, but often not in companion primary lung cancers. Methylation analysis of a subset (45/132) of these promoter regions in primary lung cancer (n = 20) and adjacent nonmalignant tissue (n = 20) showed that 31 genes had acquired methylation in the tumors, but did not show methylation in normal lung or peripheral blood cells. We studied the eight most frequently and specifically methylated genes from our lung cancer dataset in breast cancer (n = 37), colon cancer (n = 24), and prostate cancer (n = 24) along with counterpart nonmalignant tissues. We found that seven loci were frequently methylated in both breast and lung cancers, with four showing extensive methylation in all four epithelial tumors. CONCLUSIONS: By using a systematic biological screen we identified multiple genes that are methylated with high penetrance in primary lung, breast, colon, and prostate cancers. The cross-tumor methylation pattern we observed for these novel markers suggests that we have identified a partial promoter hypermethylation signature for these common malignancies. These data suggest that while tumors in different tissues vary substantially with respect to gene expression, there may be commonalities in their promoter methylation profiles that represent targets for early detection screening or therapeutic intervention.
A genome-wide screen for promoter methylation in lung cancer identifies novel methylation markers for multiple malignancies.
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View SamplesTechnologies allowing for specific regulation of endogenous genes are valuable for the study of gene functions and have great potential in therapeutics. We created the CRISPR-on system, a two-component transcriptional activator consisting of a nuclease-dead Cas9 (dCas9) protein fused with a transcriptional activation domain and single guide RNAs (sgRNAs) with complementary sequence to gene promoters. We demonstrate that CRISPR-on can efficiently activate exogenous reporter genes in both human and mouse cells in a tunable manner. In addition, we show that robust reporter gene activation in vivo can be achieved by injecting the system components into mouse zygotes. Furthermore we show that CRISPR-on can activate the endogenous IL1RN, SOX2, and OCT4 genes. The most efficient gene activation was achieved by clusters of 3 to 4 sgRNAs binding to the proximal promoters suggesting their synergistic action in gene induction. Significantly, when sgRNAs targeting multiple genes were simultaneously introduced into cells, robust multiplexed endogenous gene activation was achieved. Genome-wide expression profiling demonstrated high specificity of the system.
Multiplexed activation of endogenous genes by CRISPR-on, an RNA-guided transcriptional activator system.
Cell line
View SamplesWe conditionally inactivated mouse Cdx2, a dominant regulator of intestinal development, and mapped its genome occupancy in adult intestinal villi. Although homeotic transformation, observed in Cdx2-null embryos, was absent in mutant adults, gene expression and cell morphology were vitally compromised. Lethality was accelerated in mice lacking both Cdx2 and its homolog Cdx1, with exaggeration of defects in crypt cell replication and enterocyte differentiation. Cdx2 occupancy correlated with hundreds of transcripts that fell but not with equal numbers that rose with Cdx loss, indicating a predominantly activating role at intestinal cis-regulatory regions. Integrated consideration of a mutant phenotype and cistrome hence reveals the continued and distinct requirement in adults of a master developmental regulator that activates tissue-specific genes.
Essential and redundant functions of caudal family proteins in activating adult intestinal genes.
Specimen part
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Intestinal master transcription factor CDX2 controls chromatin access for partner transcription factor binding.
Specimen part
View SamplesWe established whether partner transcription factor binding, chromatin structure, or gene expression is compromised upon loss of partner factors cdx2 or hnf4a in mouse intestinal villi
Intestinal master transcription factor CDX2 controls chromatin access for partner transcription factor binding.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Gene expression signature for biliary atresia and a role for interleukin-8 in pathogenesis of experimental disease.
Specimen part, Time
View SamplesLiver biopsy samples were obtained from 64 infants with biliary atresia at the time of intraoperative cholangiogram. Liver biopsy samples were obtained from 14 age-matched infants with other causes of intrahepatic cholestasis, and from 7 deceased-donor children. GeneChip Human Gene 1.0 ST Array (Affymetrix, CA) were used to screen mRNAs whose expression was specifically regulated in the livers from patients with biliary atresia.
Gene expression signature for biliary atresia and a role for interleukin-8 in pathogenesis of experimental disease.
Specimen part
View SamplesNewborn Balb/c mice were injected intraperitoneally with 1.5x10^6 fluorescent-forming units (ffu) of type- A Rhesus Rotavirus (RRV) or 0.9% normal saline (NS; control) within 24 hours of birth to induce experimental model of biliary atresia. Extrahepatic bile ducts including gallbladder were microdissected en bloc at 3, 7 and 14 days after RRV or saline injections. GeneChip Mouse Gene 1.0 ST Array (Affymetrix, CA) were used to screen mRNAs whose expression was differently regulated after RRV challenge compared to normal saline controls.
Gene expression signature for biliary atresia and a role for interleukin-8 in pathogenesis of experimental disease.
Specimen part, Time
View SamplesThis study demonstrates simulated microgravity effects on E. coli K 12 MG1655 when grown on LB medium supplemented with glycerol. The results imply that E. coli readily reprograms itself to combat the multiple stresses imposed due to microgravity. Under these conditions it survives by upregulating oxidative stress protecting genes and simultaneously down regulating the membrane transporters and synthases to maintain cell homeostasis.
Effect of simulated microgravity on E. coli K12 MG1655 growth and gene expression.
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