Genome-wide analysis reveals Sall4 to be a major regulator of pluripotency in murine-embryonic stem cells.

Division of Laboratory Medicine, Nevada Cancer Institute, One Breakthrough Way, Las Vegas, NV 89135, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 01/2009; 105(50):19756-61. DOI: 10.1073/pnas.0809321105
Source: PubMed

ABSTRACT Embryonic stem cells have potential utility in regenerative medicine because of 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. By using chromatin immunoprecipitation coupled to microarray hybridization (ChIP-on-chip), we have mapped global gene targets of Sall4 to further investigate regulatory processes in W4 mouse ES cells. A total of 3,223 genes were identified that were bound by the Sall4 protein on duplicate assays with high confidence, and many of these have major functions in developmental and regulatory pathways. Sall4 bound approximately twice as many annotated genes within promoter regions as Nanog and approximately four times as many as Oct4. Immunoprecipitation revealed a heteromeric protein complex(es) between Sall4, Oct4, and Nanog, consistent with binding site co-occupancies. Decreasing Sall4 expression in W4 ES cells decreases the expression levels of Oct4, Sox2, c-Myc, and Klf4, four proteins capable of reprogramming somatic cells to an induced pluripotent state. Further, Sall4 bound many genes that are regulated in part by chromatin-based epigenetic events mediated by polycomb-repressive complexes and bivalent domains. This suggests that Sall4 plays a diverse role in regulating stem cell pluripotency during early embryonic development through integration of transcriptional and epigenetic controls.

  • [Show abstract] [Hide abstract]
    ABSTRACT: SALL4 is a transcription factor that plays essential roles in maintaining self-renewal and pluripotency of embryonic stem cells (ESCs). In fully differentiated cells, SALL4 expression is down-regulated or silenced. Accumulating evidence suggest that SALL4 expression is reactivated in cancer. Constitutive expression of SALL4 transgene readily induces acute myeloid leukemia (AML) development in mice. Gain- and loss-of-function studies reveal that SALL4 regulates proliferation, apoptosis, invasive migration, chemoresistance, and the maintenance of cancer stem cells (CSCs). SALL4 controls the expression of its downstream genes through both genetic and epigenetic mechanisms. High level of SALL4 expression is detected in cancer patients, which predicts adverse progression and poor outcome. Moreover, targeted inhibition of SALL4 has shown efficient therapeutic effects on cancer. We have summarized the recent advances in the biology of SALL4 with a focus on its role in cancer. Further study of the oncogenic functions of SALL4 and the underlying molecular mechanisms will shed light on cancer biology and provide new implications for cancer diagnostics and therapy. Copyright © 2014. Published by Elsevier Ireland Ltd.
    Cancer Letters 11/2014; · 5.02 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Epigenetic changes frequently occur during tumorigenesis and DNA hypermethylation may account for the inactivation of tumor suppressor genes in cancer cells. Studies in Multiple Myeloma (MM) have shown variable DNA methylation patterns with focal hypermethylation changes in clinically aggressive subtypes. We studied global methylation patterns in patients with relapsed/refractory MM and found that the majority of methylation peaks were located in the intronic and intragenic regions in MM samples. Therefore, we investigated the effect of methylation on miRNA regulation in MM. To date, the mechanism by which global miRNA suppression occurs in MM has not been fully described. In this study, we report hypermethylation of miRNAs in MM and perform confirmation in MM cell lines using bisulfite sequencing and methylation-specific PCR (MSP) in the presence or absence of the DNA demethylating agent 5-aza-2'-deoxycytidine. We further characterized the hypermethylation-dependent inhibition of miR-152, -10b-5p and -34c-3p which was shown to exert a putative tumor suppressive role in MM. These findings were corroborated by the demonstration that the same miRNAs were down-regulated in MM patients compared to healthy individuals, alongside enrichment of miR-152-, -10b-5p, and miR-34c-3p-predicted targets, as shown at the mRNA level in primary MM cells. Demethylation or gain of function studies of these specific miRNAs led to induction of apoptosis and inhibition of proliferation as well as down-regulation of putative oncogene targets of these miRNAs such as DNMT1, E2F3, BTRC and MYCBP. These findings provide the rationale for epigenetic therapeutic approaches in subgroups of MM.
    PLoS ONE 10/2014; 9(10):e110973. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The spalt-like transcription factor 4 (SALL4) gene has been demonstrated to be overexpressed in many malignancies, but little is known about its expression in gliomas. To explore the expression of SALL4 in patients with gliomas and the relationship between SALL4 expression and clinicopathologic characteristics, qPCR and immunohistochemical staining were used to investigate the SALL4 expression level in 54 glioma specimens and seven normal brain tissues. In vitro, siRNAs against SALL4 in U251 cell line were constructed and cell proliferation was evaluated by CCK8 assay. The SALL4 expression level in glioma was significantly higher than that in normal brain tissues (P < 0.05). Both qPCR and immunohistochemical analysis found that the expression of SALL4 was tightly correlated with glioma pathology grade (P < 0.05). Analysis using glioma and normal brain tissues revealed that SALL4 was positively proportionated to glioma cell differentiation with high sensitivity (92.59 %) and specificity (85.71 %). Survival analysis indicated the SALL4 expression was an independent prognostic factor. High level of SALL4 expression was correlated with poor outcome in patients with gliomas. This result agreed with the negative correlation between SALL4 expression and overall survival period obtaining in GBM patients from the cancer genome atlas database. The CCK8 experiments demonstrated SALL4 could significantly inhibit cell proliferation in U251 cell line (P < 0.05). The findings of the current study indicated that the SALL4 may play an important role in progression, development and maintenance of glioma.
    Journal of Neuro-Oncology 10/2014; · 3.12 Impact Factor

Full-text (2 Sources)

Available from
May 17, 2014