Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

SALL4 ChIP-chip using NimbleGen HG18 RefSeq Promoter tiling array (2.7kb)

ABSTRACT: Increasing studies suggest that SALL4 may play vital roles in leukemogenesis. We have used chromatin immunoprecipitation followed by microarray hybridization as a screening tool to determine potential genes that may account for the role SALL4 plays in leukemogenesis. Analysis of SALL4 binding sites reveals that genes involved in cell death, cancer, DNA replication/repair, and cell cycle were highly enriched (p<0.05). These genes include 38 important apoptosis-inducing genes (TNF, TP53, PTEN, CARD9, CARD11, CYCS, LTA) and apoptosis-inhibiting genes (Bmi-1, BCL2, XIAP, DAD1, TEGT). Real-time PCR has shown that expression levels of these genes changed significantly after SALL4 knockdown, which ubiquitously led to cell apoptosis. Flow cytometry revealed that reduction of SALL4 expression in NB4 and other leukemia cell lines dramatically increased caspase-3, Annexin V, and DNA fragmentation activity. Bromodeoxyuridine-incorporation assays showed decreased numbers of S phase cells and increased numbers of G1- and G2- phase cells indicating reduced DNA synthesis, consistent with results from cell proliferation assays. In addition, NB4 cells that express low levels of SALL4 have significantly decreased tumorigenecity in immunodeficient mice. Our studies provide a foundation in the development of leukemia stem cell-specific therapy by targeting SALL4. Keywords: ChIP-chip The global targets of SALL4 were determined using a NimbleGen promoter tiling array (2.7kb, information below) in the human cell line NB4. Because SALL4 is thought to play a significant role in leukemogenesis we focused primarily on genes involved in apoptosis and only used the ChIP-chip array as a screening tool to identify potential genes that may bind these genes. Upon identification and verification of apoptosis genes bound by SALL4 we utilized functional assays to determine the effect of SALL4 on these genes. In addition, gene expression profiling was used to determine pathways functionally altered by Sall4 reduction. Source: UCSC Build: HG18 Probe Length: 50-75mer Median Probe Spacing: 100bp Probes per Array: 385,000 Feature Size: 16Î¼m x 16Î¼m Array Dimensions: 17.4mm x 13mm Overall Slide Dimensions: 1" x 3" (25 x 75mm) Recommended Storage: Store arrays desiccated at room temperature. Promoter tiling from 2200bp upstream and 500bp downstream of the transcription start site for RefSeq genes.

ORGANISM(S): Homo sapiens

SUBMITTER: Li Chai

PROVIDER: E-GEOD-10734 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

SALL4 is a key regulator of survival and apoptosis in human leukemic cells.

Yang Jianchang J Chai Li L Gao Chong C Fowles Taylor C TC Alipio Zaida Z Dang Hien H Xu Dan D Fink Louis M LM Ward David C DC Ma Yupo Y

Blood 20080516 3

Increasing studies suggest that SALL4 may play vital roles in leukemogenesis and stem cell phenotypes. We have mapped the global gene targets of SALL4 using chromatin immunoprecipitation followed by microarray hybridization and identified more than 2000 high-confidence, SALL4-binding genes in the human acute promyelocytic leukemic cell line, NB4. Analysis of SALL4-binding sites reveals that genes involved in cell death, cancer, DNA replication/repair, and cell cycle were highly enriched (P < .05 ...[more]

PMID: 18487508

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Project description:Embryonic stem cells have potential utility in regenerative medicine due to their pluripotent characteristics. Sall4, a zinc-finger transcription factor, is expressed very early in embryonic development with Oct4 and Nanog, two well characterized pluripotency regulators. Sall4 plays an important role in governing the fate of stem cells through transcriptional regulation of both Oct4 and Nanog. Using chromatin immunoprecipitation coupled to microarray hybridization (ChIP on Chip), we have mapped global gene targets of Sall4 unveiling possible regulation of broad ES cell functions. Approximately 5,000 genes were identified that were bound by the Sall4 protein and many of these have major functions in developmental and regulatory pathways. Sall4 bound more than six times as many annotated genes within promoter regions as Oct4 and twice as many as Nanog. Immunoprecipitation revealed a heterotrimeric protein complex between Sall4, Oct4, and Nanog, consistent with binding site co-occupancies. Further, Sall4 bound many genes that are regulated in part by the chromatin-based epigenetic events mediated by polycomb-repressive complexes and bivalent domains. This suggests that Sall4 plays a central and diverse role in regulating stem cell pluripotency during early embryonic development that involves integration of transcriptional and epigenetic control processes. Keywords: ChIP-chip We used ChIP-chip to map global promoter bound by Sall4, a zinc finger transcription factor. Growing evidence has suggested that Sall4 plays a vital role in ES cell pluripotency maintenance. Evidence for this includes its recent use as a marker for somatic cell reprogramming, in a genetic signature for ES cells, and evidence that Sall4 enhances reprogramming. These recent findings and two previously described interactions with Oct4 and Nanog strongly support the role of Sall4 in ES cells. This hypothesis was furthered here as we show that Sall4 plays important roles through transcriptional regulation of vital ES cell genes.

Project description:Glioblastoma multiforme (GBM) is the most prevalent type of adult brain tumor, and one of the deadliest tumors known to mankind. The genetic understanding of GBM is, however, limited, and the molecular mechanisms which facilitate GBM cell survival and growth within the tumor microenvironment are largely unknown. We applied digital karyotyping and single nucleotide polymorphism (SNP) arrays to screen for copy number changes in GBM samples and found that the most frequently amplified region is at chromosome 7p11.2. The high resolution of digital karyotyping and SNP arrays permits the precise delineation of amplicon boundaries and has enabled identification of the minimal region of amplification at 7p11.2, which contains two genes, EGFR and SEC61?. SEC61? encodes a subunit of a heterotrimeric protein channel located in the endoplasmic reticulum (ER). In addition to its high frequency of gene amplification in GBMs, SEC61? is also remarkably overexpressed in 77% of GBMs, but not in lower-grade gliomas. The siRNA-mediated knockdown of SEC61? expression in tumor cells led to growth suppression and apoptosis. Furthermore, we showed that pharmacological ER stress agents induce SEC61? expression in GBM cells. Together, these results indicate that aberrant expression of SEC61? serves significant roles in GBM cell survival, likely via a mechanism that is involved in the cytoprotective ER stress-adaptive response to the tumor microenvironment. hSETD1A was silenced in HCT116 cells using retrovirus harboring shRNA specifically against the hSETD1A gene. 10?g RNA was reverse transcribed to cDNA using the Applied Biosystems High Capacity cDNA Reverse Transcription kit according to the manufacturer’s instructions (Applied Biosystems). cDNA products were treated with 100ng RNaseA and then purified using the Qiagen PCR purification kit according to the manufacturer’s instructions. NimbleGen Human Gene Expression array was purchased from Roche Applied Sciences. cDNA samples were labeled, Cy3 hybridized, and processed at the FSU NimbleGen Microarray Facility at Florida State University.

Dataset Information

SALL4 ChIP-chip using NimbleGen HG18 RefSeq Promoter tiling array (2.7kb)

Publications

SALL4 is a key regulator of survival and apoptosis in human leukemic cells.

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