Divergent expression patterns of SATB1 mRNA and SATB1 protein in colorectal cancer and normal tissues

Impaired Expression of the Salvador Homolog-1 Gene Is Associated with the Development and Progression of Colorectal Cancer

Salvador homolog-1 (SAV1) is a component of the Hippo pathway that regulates tissue growth and homeostasis by affecting diverse cell processes, including apoptosis, cell division, and differentiation. The aberrant expression of Hippo pathway components has been observed in various human cancers. This study aimed to examine the expression level of the SAV1 gene in colorectal cancer (CRC) and its prognostic value and associations with tumor progression. We obtained matched pairs of tumor tissue and non-cancerous mucosa of the large intestine from 94 CRC patients as well as 40 colon biopsies of healthy subjects collected during screening colonoscopy. The tissue samples and CRC cell lines were quantified for SAV1 mRNA levels using the quantitative polymerase chain reaction method, while SAV1 protein expression was estimated in the paired tissues of CRC patients using immunohistochemistry. The average level of SAV1 mRNA was decreased in 93.6% of the tumor tissues compared to the corresponding non-cancerous tissues and biopsies of healthy colon mucosa. A downregulated expression of SAV1 mRNA was also noted in the CRC cell lines. Although the average SAV1 immunoreactivity was increased in the CRC samples compared to the non-cancerous tissues, a decreased immunoreactivity of the SAV1 protein in the tumor specimens was associated with lymph node involvement and higher TNM disease stage and histological grade. The results of our study suggest that the impaired expression of SAV1 is involved in CRC progression.

Altered Expression of DDR1 in Clear Cell Renal Cell Carcinoma Correlates With miR-199a/b-5p and Patients' Outcome

BACKGROUND/AIM

Accumulating evidence suggests that discoidin domain receptor tyrosine kinase 1 (DDR1) has an oncogenic role. Therefore, the aim of this study was to evaluate the potential utility of DDR1 and its post-transcriptional repressors, miR-199a-5p and miR-199b-5p, as prognostic factors in clear cell renal cell carcinoma (ccRCC).

PATIENTS AND METHODS

The expression of DDR1 in tumor and normal renal tissues of 56 patients with ccRCC was assessed by reverse transcription quantitative polymerase chain reaction, western blotting and immunohistochemistry. Renal cancer cells were transfected with specific RNA sequences to validate DDR1 as a putative miR-199a/b-5p target.

RESULTS

Decreased DDR1 mRNA and protein, as well as miR-199a/b-5p levels were found in ccRCC. Low DDR1 protein was associated with higher nuclear grade and shorter overall survival. DDR1 immunoreactivity was elevated in the nuclei and unchanged in the membrane/cytoplasmic compartment of tumor cells. DDR1 levels correlated with those of miR-199a/b-5p. In addition, we validated DDR1 as a target gene for miR-199a/b-5p in renal cancer cell lines.

CONCLUSION

DDR1 expression is altered in ccRCC, but our findings do not support its oncogenic role. In-depth investigation will be necessary to elucidate the exact role and potential utility of miR-199a/b-5p in ccRCC.

The Role of SATB1 in Tumour Progression and Metastasis

Carcinogenesis is a long-drawn, multistep process, in which metastatic spread is an unequivocal hallmark of a poor prognosis. The progression and dissemination of epithelial cancers is commonly thought to rely on the epidermal-mesenchymal transition (EMT) process. During EMT, epithelial cells lose their junctions and apical-basal polarity, and they acquire a mesenchymal phenotype with its migratory and invasive capabilities. One of the proteins involved in cancer progression and EMT may be SATB1 (Special AT-Rich Binding Protein 1)-a chromatin organiser and a global transcriptional regulator. SATB1 organizes chromatin into spatial loops, providing a "docking site" necessary for the binding of further transcription factors and chromatin modifying enzymes. SATB1 has the ability to regulate whole sets of genes, even those located on distant chromosomes. SATB1 was found to be overexpressed in numerous malignancies, including lymphomas, breast, colorectal, prostate, liver, bladder and ovarian cancers. In the solid tumours, an elevated SATB1 level was observed to be associated with an aggressive phenotype, presence of lymph node, distant metastases, and a poor prognosis. In this review, we briefly describe the prognostic significance of SATB1 expression in most common human cancers, and analyse its impact on EMT and metastasis.

SATB1 Expression of Colorectal Adenomatous Polyps is Higher than that of Colorectal Carcinomas

"Special AT-rich sequence-binding protein-1" (SATB1) is a global genome organizer and is found to have effects on carcinogenesis and progression of various malignancies including colorectal carcinoma (CRC). We aimed to investigate the expression of SATB1 in CRC and colorectal adenomatous polyps (CAP), the correlation between clinicopathologic parameters, and overall survival. We examined 227 CRCs and 129 CAPs. SATB1 protein expression was evaluated by immunohistochemistry. We found higher SATB1 expression in adenomatous epithelium than in CRC tissues (55.0% vs. 42.7%, respectively) (P<0.05). None of the adjacent normal colorectal mucosa stained positive in CRC cases, and only one of the adjacent normal mucosa of the CAP cases was positive. SATB1 expression of left-sided CRC was higher than that of right-sided CRC (46.3% vs. 28.6%, respectively) (P<0.05), and SATB1 expression of conventional adenocarcinomas was higher than that of mucinous carcinomas (45.5% vs. 6.3%, respectively) (P<0.05). SATB1 expression was higher in CAPs consisting of high-grade dysplasia than in polyps with low-grade dysplasia (77.8% vs. 51.4%) (P<0.05). SATB1 expression did not correlate with patients' overall survival. In conclusion, due to the higher expression of SATB1 in CAP than in CRC, we think SATB1 may have a role in the early stages of carcinogenesis of CRCs. This is the first study investigating SATB1 expression in CAPs. Besides this is the first report that shows different SATB1 expressions in conventional colorectal adenocarcinoma and mucinous carcinoma, and also in right-sided and left-sided CRC. Our results, with supporting new studies, can provide SATB1 as a possible candidate for targeted therapy for CRC patients.

Divergent SATB1 expression across human life span and tissue compartments

Special AT-rich binding protein-1 (SATB1) is a global chromatin organizer capable of activating or repressing gene transcription in mice and humans. The role of SATB1 is pivotal for T-cell development, with SATB1-knockout mice being neonatally lethal, although the exact mechanism is unknown. Moreover, SATB1 is dysregulated in T-cell lymphoma and proposed to suppress transcription of the Pdcd1 gene, encoding the immune checkpoint programmed cell death protein 1 (PD-1). Thus, SATB1 expression in T-cell subsets across different tissue compartments in humans is of potential importance for targeting PD-1. Here, we comprehensively analyzed SATB1 expression across different human tissues and immune compartments by flow cytometry and correlated this with PD-1 expression. We investigated SATB1 protein levels in pediatric and adult donors and assessed expression dynamics of this chromatin organizer across different immune cell subsets in human organs, as well as in antigen-specific T cells directed against acute and chronic viral infections. Our data demonstrate that SATB1 expression in humans is the highest in T-cell progenitors in the thymus, and then becomes downregulated in mature T cells in the periphery. Importantly, SATB1 expression in peripheral mature T cells is not static and follows fine-tuned expression dynamics, which appear to be tissue- and antigen-dependent. Furthermore, SATB1 expression negatively correlates with PD-1 expression in virus-specific CD8⁺ T cells. Our study has implications for understanding the role of SATB1 in human health and disease and suggests an approach for modulating PD-1 in T cells, highly relevant to human malignancies or chronic viral infections.

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.

Prognostic and Clinicopathological Significance of SATB1 in Colorectal Cancer: A Meta-Analysis

Background: A large number of studies have reported the aberrant expression of special AT-rich sequence binding protein 1 (SATB1) in colorectal cancer (CRC). However, the role of SATB1 in CRC is still controversial. Therefore, we performed this meta-analysis to elucidate the prognostic and clinical value of SATB1 in CRC patients.

Methods: We searched Web of Science, EMBASE and PubMed entirely in January 2018 to identify related articles. Pooled Hazard ratio (HR) was adopted to evaluate the prognostic value of SATB1 in CRC and odd ratio (OR) was used to assess the clinicopathological significance of SATB1 in CRC.

Results: Ten eligible studies containing 7 on prognosis and 9 on clinicopathological characteristics were finally included in the present meta-analysis. Results revealed that patients with high expression of SATB1 tended to have shorter overall survival (OS) (pooled HR: 1.64, 95% CI: 1.04–2.57). Besides, we also discovered that the expression of SATB1 was associated with histologic grade (OR = 1.88, 95% CI: 1.06–3.34), distant metastasis (OR = 1.43, 95% CI: 1.11–1.85) and lymph node metastasis (OR = 1.50, 95% CI: 1.03–2.19).

Conclusion: Broadly speaking, our meta-analysis demonstrated that high expression level of SATB1 was related to poor prognosis in CRC patients.

Prognostic significance of SATB1 in gastrointestinal cancer: a meta-analysis and literature review

Background

The special AT-rich sequence-binding proteins 1 (SATB1) is a major regulator involved in cell differentiation. It has been shown that SATB1 acts as an oncogenic regulator. The clinical and prognostic significance of SATB1 in gastrointestinal cancer remains controversial. The purpose of this study is to conduct a systematic review and meta-analysis to elucidate the impact of SATB1 in gastrointestinal cancer.

Results

A total of 3174 gastrointestinal cancer patients from 15 studies were included. The correlation between SATB1 expression and OS or RFS was investigated in 12 and 5 studies respectively. The results of meta-analysis showed that SATB1 overexpression is inversely correlated with OS (combined HR: 1.79, p = 0.0003) and RFS (combined HR: 2.46, p < 0.0001). In subgroup analysis, SATB1 expression is significantly correlated with poor prognosis in gastrointestinal cancer in Asian population. SATB1 expression is associated with stage, invasion depth, lymph node metastasis and distant metastasis.

Methodology

Published studies with data on overall survival (OS) and/or relapse free survival (RFS) and SATB1 expression were searched from Cochrane Library, PubMed and Embase (up to Dec 30, 2016). The outcome measurement is hazard ratio (HR) for OS or RFS related with SATB1 expression. Two reviewers independently screened the literatures, extracted the data and performed meta-analysis using RevMan 5.3.0 software. The combined HRs were calculated by fixed- or random-effect models.

Conclusions

The results of this meta-analysis suggest that SATB1 overexpression is related to advanced stage, lymph node metastasis and distant metastasis. SATB1 overexpression is a marker indicating poor prognosis in gastrointestinal cancer.

SATB1 overexpression correlates with gastrointestinal neoplasms invasion and metastasis: a meta-analysis for Chinese population

Background

Gastrointestinal neoplasm (GIN) is the most common neoplasm in China. The global chromatin organizer SATB1 (special AT-rich sequence binding protein 1) is aberrantly expressed in multiple human neoplasms. We conducted this meta-analysis to investigate whether the invasion and metastasis of GIN correlates with SATB1 levels in tumor tissues in Chinese patients.

Materials and Methods

Eligible studies were identified through multiple search strategies in the databases PubMed, Embase, Medline, CNKI, and WANFANG, and the relevant clinicopathological data were extracted. Data were pooled using the Mantel-Haenszel fixed-effects or DerSimonian-Laid random-effects model.

Results

Fourteen studies consisting of 1622 patients were included. There were 3, 3, and 8 studies that evaluated esophageal, gastric, and colorectal cancers, respectively. The overall mean percentage of patients with elevated SATB1 levels was 47.84%. Among patients with GIN, SATB1 overexpression was associated with depth of invasion (T stage: RR 1.27, 95% CI 1.18–1.36, P = 0.000), regional lymph node metastasis (N stage: RR 1.51, 95% CI 1.22–1.87, P = 0.000), and distant metastasis (M stage: RR 2.54, 95% CI 1.46–4.41, P = 0.001). The tumor type most closely linked with invasion and metastasis in GIN was gastric cancer (RR for T stage: 1.64, RR for N stage: 1.68, RR for M stage: 3.15).

Conclusions

invasion and metastasis of GIN in Chinese patients correlates with SATB1 overexpression in tumor tissues, most profoundly in gastric cancer.

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.

SATB1 and SATB2 play opposing roles in c-Myc expression and progression of colorectal cancer

Special AT-rich sequence-binding protein 1 and 2 (SATB1/2) are nuclear matrix-associated proteins involved in chromatin remodeling and regulation of gene expression. SATB2 acts as a tumor suppressor in laryngeal squamous cell carcinoma and colon cancer, whereas SATB1 promotes the progression of numerous types of cancers. In this study, we examined the effects of SATB1 and SATB2 on the malignant characteristics of colorectal cancer cells. SATB1 and SATB2 expression were negatively correlated in colorectal cancer specimens. SATB1 expression was increased, whereas SATB2 expression was reduced, in colorectal cancer tissues compared to control tissues. Exogenous expression of SATB2 in colorectal cancer cells suppressed cell proliferation, colony formation and tumor proliferation in mice. c-Myc was reduced by SATB2 expression, and exogenous expression of c-Myc in SATB2-expressing cells restored proliferation, colony formation and in vivo tumor growth of colorectal cancer cells. We also showed that c-Myc reduction by SATB2 was mediated by the inactivation of ERK5. In contrast, SATB1 promoted c-Myc expression. The expression of SATB1 in colorectal cancer tissues was positively correlated with c-Myc expression, and SATB1 knockdown reduced c-Myc expression in colorectal cancer cells. Finally, we showed that SATB1 knockdown in colorectal cancer cells suppressed cell proliferation, colony formation and cell invasion. Our results reveal interesting features of how the structural homologs SATB1 and SATB2 exert opposing functions in colorectal tumorigenesis.