Relationship between SATB1 expression and prognosis in astrocytoma

Poor prognosis and SATB1 overexpression in solid tumors: a meta-analysis

Background

Several previous studies have reported the prognostic value of special AT-rich sequence-binding protein 1 (SATB1) in solid tumors. However, these studies produced inconsistent results because of their various limitations, including small sample sizes. Here, we describe a meta-analysis based on 17 studies including 3144 patients to search for connections between SATB1 overexpression and overall survival (OS) of patients with solid tumors. Seventeen studies (n = 3144) were assessed in the meta-analysis. Both univariate and multivariate analysis for survival indicated that high SATB1 reactivity significantly predicted poor prognosis. In the multivariate analysis, the combined hazard ratio (HR) for OS was 1.82 (95% confidence interval [CI]: 1.59–2.08, P < 0.0001). The pooled HR of the univariate analysis for OS was 1.96 (95% CI: 1.65–2.34, P < 0.0001).

Methods

Studies were identified by an electronic search of PubMed, EMBASE, and Web of Science, including publications prior to April 2017. Pooled HR values for OS were aggregated and quantitatively analyzed in the meta-analysis.

Conclusion

The meta-analysis indicated that high SATB1 reactivity is significantly correlated with decreased survival in most cases of solid tumors. In addition, SATB1 shows promise as a prognostic biomarker and novel therapeutic target on the basis of its expression level in solid tumors.

Nanoparticle/siRNA-based therapy strategies in glioma: which nanoparticles, which siRNAs?

Nanomedicines allow for the delivery of small interfering RNAs (siRNAs) that are otherwise barely suitable as therapeutics for inducing RNA interference (RNAi). In preclinical studies on siRNA-based glioma treatment in vivo, various groups of nanoparticle systems, routes of administration and target genes have been explored. Targeted delivery by functionalization of nanoparticles with a ligand for crossing the blood-brain barrier and/or for enhanced target cell transfection has been described as well. Focusing on nanoparticle developments in the last approximately 10 years, this review article gives a comprehensive overview of nanoparticle systems for siRNA delivery into glioma and of preclinical in vivo studies. Furthermore, it discusses various target genes and highlights promising strategies with regard to target gene selection and combination therapies.

Analysis of cellular and molecular antitumor effects upon inhibition of SATB1 in glioblastoma cells

Background

The Special AT-rich Sequence Binding Protein 1 (SATB1) regulates the expression of many genes by acting as a global chromatin organizer. While in many tumor entities SATB1 overexpression has been observed and connected to pro-tumorigenic processes, somewhat contradictory evidence exists in brain tumors with regard to SATB1 overexpression in glioblastoma and its association with poorer prognosis and tumor progression. On the functional side, initial data indicate that SATB1 may be involved in several tumor cell-relevant processes.

Methods

For the detailed analysis of the functional relevance and possible therapeutic potential of SATB1 inhibition, we employ transient siRNA-mediated knockdown and comprehensively analyze the cellular and molecular role of SATB1 in glioblastoma.

Results

In various cell lines with different SATB1 expression levels, a SATB1 gene dose-dependent inhibition of anchorage-dependent and –independent proliferation is observed. This is due to cell cycle-inhibitory and pro-apoptotic effects of SATB1 knockdown. Molecular analyses reveal SATB1 knockdown effects on multiple important (proto-) oncogenes, including Myc, Bcl-2, Pim-1, EGFR, β-catenin and Survivin. Molecules involved in cell cycle, EMT and cell adhesion are affected as well. The putative therapeutic relevance of SATB1 inhibition is further supported in an in vivo tumor xenograft mouse model, where the treatment with polymeric nanoparticles containing SATB1-specific siRNAs exerts antitumor effects.

Conclusion

Our results demonstrate that SATB1 may represent a promising target molecule in glioblastoma therapy whose inhibition or knockdown affects multiple crucial pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3006-6) contains supplementary material, which is available to authorized users.

Pilot study special AT-rich sequence-binding protein 1 investigating as a potential biomarker for esophageal squamous cell carcinoma

In the present study, we aimed to evaluate the expression of special AT-rich sequence-binding protein 1 (SATB1) in esophageal squamous cell carcinoma (ESCC) and assess the correlation between its expression and the clinicopathological features and prognosis of the disease. SATB1 expression in ESCC tissue was determined by using immunohistochemical analysis, quantitative real-time polymerase chain reaction, and western blot analysis. The relationship between SATB1 expression and clinicopathological features was examined by using the chi-squared test, and the survival rate was calculated by using the Kaplan-Meier survival curve. The correlation between the indicators and patient survival was estimated by using a Cox regression analysis. High SATB1 expression in was detected in 48.3% and 7.8% of ESCC and normal esophagus tissues (P < 0.05), respectively. SATB1 expression did not significantly correlate with clinicopathological features. The Kaplan-Meier curve indicated that patients with high SATB1 expression had significantly shorter survival than those with low SATB1 expression. In a multivariate Cox regression model, high SATB1 expression was identified as an independent prognostic factor for patients with ESCC. In conclusion, these results suggest that high SATB1 expression is predictive of poor prognosis in ESCC and may be a promising new candidate for targeted therapies for ESCC.

SATB1 Mediates Long-Range Chromatin Interactions: A Dual Regulator of Anti-Apoptotic BCL2 and Pro-Apoptotic NOXA Genes

Aberrant expression of special AT-rich binding protein 1 (SATB1), a global genomic organizer, has been associated with various cancers, which raises the question of how higher-order chromatin structure contributes to carcinogenesis. Disruption of apoptosis is one of the hallmarks of cancer. We previously demonstrated that SATB1 mediated specific long-range chromosomal interactions between the mbr enhancer located within 3’-UTR of the BCL2 gene and the promoter to regulate BCL2 expression during early apoptosis. In the present study, we used chromosome conformation capture (3C) assays and molecular analyses to further investigate the function of the SATB1-mediated higher-order chromatin structure in co-regulation of the anti-apoptotic BCL2 gene and the pro-apoptotic NOXA gene located 3.4Mb downstream on Chromosome 18. We demonstrated that the mbr enhancer spatially juxtaposed the promoters of BCL2 and NOXA genes through SATB1-mediated chromatin-loop in Jurkat cells. Decreased SATB1 levels switched the mbr-BCL2 loop to mbr-NOXA loop, and thus changed expression of these two genes. The SATB1-mediated dynamic switch of the chromatin loop structures was essential for the cooperative expression of the BCL2 and NOXA genes in apoptosis. Notably, the role of SATB1 was specific, since inhibition of SATB1 degradation by caspase-6 inhibitor or caspase-6-resistant SATB1 mutant reversed expression of BCL-2 and NOXA in response to apoptotic stimulation. This study reveals the critical role of SATB1-organized higher-order chromatin structure in regulating the dynamic equilibrium of apoptosis-controlling genes with antagonistic functions and suggests that aberrant SATB1 expression might contribute to cancer development by disrupting the co-regulated genes in apoptosis pathways.

Nicotinamide induces apoptosis of F9 mouse teratocarcinoma stem cells by downregulation of SATB1 expression

The aim of this study was to decide whether nicotinamide (NA) could induce apoptosis of F9 mouse teratocarcinoma stem cells (MF9) by downregulation of special AT-rich sequence binding protein 1 (SATB1) expression. We used different concentrations of NA (0, 1.5, 2, and 2.5 mmol/L) to treat MF9 cells and analyze SATB1 expression by RT-qPCR and Western blotting; in addition, the cell proliferation was detected in a microplate reader with Cell Counting Kit-8 (CCK-8), and the cell cycle and apoptosis were analyzed using flow cytometry. We found that the expression of SATB1 was decreased significantly in NA-treated groups than in the control group, and its expression level was inversely related to the NA concentration. In addition, CCK-8 analysis showed that NA significantly inhibited the proliferation of MF9 cells, and flow cytometry showed that NA blocked MF9 cells to G1 phase and significantly promoted apoptosis in any treated groups. To confirm the results, we constructed small interference RNA (siRNA) targeting at mouse SATB1 and transferred into MF9 cells. The results indicated that the expression of SATB1 in both mRNA and protein levels was significantly decreased after cells transferred with siRNA sequence for 48 h, the proliferation of MF9 cells was significantly inhibited, and most of MF9 cells were blocked at G1 phase, and the apoptosis rate was increased obviously. The results showed that NA could inhibit the proliferation and induce apoptosis of MF9 cells. These findings might be used as an efficient candidate for teratocarcinoma therapy.

Overexpression of Special AT-Rich Sequence-Binding Protein 1 in Endometrial Cancer: A Clinicopathologic Study

Objective

Special AT-rich sequence-binding protein 1 (SATB1), as a genome organizer, serves important functions in tumor progression and metastasis. The SATB1 is overexpressed in various malignant tumors. However, the expression and prognostic value of SATB1 in endometrial cancer remain unknown. The aim of this study was to explore the prognostic values of SATB1 expression in endometrial cancer.

Methods/Materials

We investigated the expression of SATB1 in 172 untreated endometrial cancer tissues and 25 normal endometrial tissues through immunohistochemical staining. We also analyzed the association of SATB1 level with clinicopathologic parameters and determined its prognostic significance.

Result

Special AT-rich sequence-binding protein 1 was expressed in 78 (45.3%) of the 172 endometrial cancer samples, but not in the normal endometrial samples. The positive expression of SATB1 was associated with clinicopathologic factors, such as International Federation of Gynecology and Obstetrics stage, histological grade, myometrial invasion depth, lymph node metastasis, vascular/lymphatic invasion, and recurrence. The patients with positive SATB1 expression had worse overall survival and disease-free survival rates than the patients with negative SATB1 expression (P< 0.001 for both). Multivariate Cox analysis indicated that SATB1 was an independent parameter for overall survival (hazards ratio, 2.928; 95% confidence interval, 1.072–7.994;P= 0.036) and disease-free survival (hazards ratio, 2.825; 95% confidence interval, 1.111–7.181;P= 0.029).

Conclusions

Results showed that SATB1 may be involved in tumor development and progression in endometrial cancer, may serve as a promising biomarker for predicting the prognosis of endometrial cancer patients, and thus may act as a novel target for treating endometrial carcinoma.

Multiple effects of the special AT-rich binding protein 1 (SATB1) in colon carcinoma

SATB1 (special AT-rich binding protein 1) is a global chromatin organizer regulating the expression of a large number of genes. Overexpression has been found in various solid tumors and positively correlated with prognostic and clinicopathological properties. In colorectal cancer (CRC), SATB1 overexpression and its correlation with poor differentiation, invasive depth, TNM (tumor, nodes, metastases) stage and prognosis have been demonstrated. However, more detailed studies on the SATB1 functions in CRC are warranted. In this article, we comprehensively analyze the cellular and molecular role of SATB1 in CRC cell lines with different SATB1 expression levels by using RNAi-mediated knockdown. Using siRNAs with different knockdown efficacies, we demonstrate antiproliferative, cell cycle-inhibitory and proapoptotic effects of SATB1 knockdown in a SATB1 gene dose-dependent manner. Tumor growth inhibition is confirmed in vivo in a subcutaneous tumor xenograft mouse model using stable knockdown cells. The in-depth analysis of cellular effects reveals increased activities of caspases-3, -7, -8, -9 and other mediators of apoptotic pathways. Similarly, the analysis of E- and N-cadherin, slug, twist, β-catenin and MMP7 indicates SATB1 effects on epithelial-mesenchymal transition (EMT) and matrix breakdown. Our results also establish SATB1 effects on receptor tyrosine kinases and (proto-)oncogenes such as HER receptors and Pim-1. Taken together, this suggests a more complex molecular interplay between tumor-promoting and possible inhibitory effects in CRC by affecting multiple pathways and molecules involved in proliferation, cell cycle, EMT, invasion and cell survival.

Role of special AT rich sequence binding protein 1 in digestive system neoplasms

Special AT rich sequence binding protein 1 (SATB1) is a unique global regulatory factor. Epigenetic modifications and dynamic changes in chromatin organization mediated by SATB1 have recently been shown to play an important role in regulating cancer-promoting genes. The role of SATB1 in promoting metastasis was discovered in breast carcinoma cells in 2008. In recent years, high expression of SATB1 has been found in digestive system neoplasms including oral cancer, stomach cancer, liver cancer, gallbladder cancer and colorectal cancer. SATB1 is related closely to proliferation, invasion and metastasis of tumor cells. Digestive system neoplasms are the most common malignant tumor in China, and control of cancer metastasis has been the research focus. A better understanding of the role of SATB1 will contribute to the diagnosis, treatment and prognosis evaluation in malignant tumors. In this review, we will summarize recent progress in understanding the role of SATB1 in digestive system neoplasms.