SATB1 and bladder cancer: Is there a functional link?

Elevated Expression of SATB1 Predicts Unfavorable Clinical Outcomes in Colon Adenocarcinoma

BACKGROUNDS

Special AT-rich sequence-binding protein 1 (SATB1) belongs to the chromatin-remodeling protein which regulates different genes expression. High expression of SATB1 was found to be associated with the development of certain carcinomas. However, the functions of SATB1 in colon adenocarcinoma (CAC) remains unclear yet. Our study aims to investigate the potential role of SATB1 in CAC and whether it is associated with the unfavorable symptoms of CAC patients.

METHODS

The expression pattern of SATB1 was measured in CAC samples and adjacent noncancerous samples through quantitative real-time polymerase chain reaction and immunohistochemistry staining. We performed univariate and multivariate analyses to evaluate the clinical role of SATB1 in enrolled patients. The Kaplan-Meier analyses and log-rank tests were carried out to assess the clinicopathologic characteristics. The effect of SATB1 in human colon cancer cells was examined through cellular experiments.

RESULTS

The expression level of SATB1 in CAC tissues was significantly elevated compared with adjacent control tissues. High expression of SATB1 in tumor tissue was found to be associated with lymph node metastasis and advanced TNM stage. Higher SATB1 level in CAC patients indicated a worse 5-year survival time. Moreover, high SATB1 was defined as an independent poor prognostic factor. Cellular experiments showed that inhibition of the SATB1 protein level in human colon cells could suppress the migration and invasion capabilities.

CONCLUSIONS

Our findings revealed that high expression of SATB1 was significantly correlated with the poor clinical features and prognosis of CAC patients. It indicated that SATB1 might serve as a potential prognostic predictor and novel drug target for CAC treatment.

Identification of a chromatin regulator signature and potential candidate drugs for bladder cancer

Background

Bladder cancer (BLCA) is a malignant tumor with a dismay outcome. Increasing evidence has confirmed that chromatin regulators (CRs) are involved in cancer progression. Therefore, we aimed to explore the function and prognostic value of CRs in BLCA patients.

Methods

Chromatin regulators (CRs) were acquired from the previous top research. The mRNA expression and clinical information were downloaded from TCGA and GEO datasets. Cox regression analysis and least absolute shrinkage and selection operator (LASSO) regression analysis were performed to select the prognostic gene and construct the risk model for predicting outcome in BLCA. The Kaplan-Meier analysis was used to assess the prognosis between high- and low-risk groups. We also investigated the drug sensitivity difference between high- and low-risk groups. CMAP dataset was performed to screen the small molecule drugs for treatment.

Results

We successfully constructed and validated an 11 CRs-based model for predicting the prognosis of patients with BLCA. Moreover, we also found 11 CRs-based model was an independent prognostic factor. Functional analysis suggested that CRs were mainly enriched in cancer-related signaling pathways. The CR-based model was also correlated with immune cells infiltration and immune checkpoint. Patients in the high-risk group were more sensitive to several drugs, such as mitomycin C, gemcitabine, cisplatin. Eight small molecule drugs could be beneficial to treatment for BLCA patients.

Conclusion:

In conclusion, our study provided novel insights into the function of CRs in BLCA. We identified a reliable prognostic biomarker for the survival of patients with BLCA.

Long Non-Coding RNA ELFN1-AS1 Promoted Colon Cancer Cell Growth and Migration via the miR-191-5p/Special AT-Rich Sequence-Binding Protein 1 Axis

Long non-coding RNAs (lncRNAs) are reported to participate in tumor development. It has been manifested in previous researches that lncRNA ELFN1-AS1 is involved in early-stage colon adenocarcinoma with potential diagnostic value. However, no studies have revealed the specific mechanism of ELFN1-AS1 in colon cancer, and there are no other studies on whether ELFN1-AS1 is associated with tumorigenesis. In our study, ELFN1-AS1 with high expression in colon cancer was selected by TCGA analysis, and the survival analysis was carried out to verify it. Subsequently, qRT-PCR was adopted for validating the results in tissues and cell lines. Cell counting kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU), cell colon, cell apoptosis, cell cycle, cell migration, and invasion assays were utilized to assess the role of ELFN1-AS1 in colon cancer. Results uncovered that ELFN1-AS1 expression was prominently raised in colon cancer cells and tissues. ELFN1-AS1 decrement restrained cells to grow through interfering with distribution of cell cycle and promoting apoptosis. Meanwhile, ELFN1-AS1 decrement weakened the capacity of cells to migrate and invade. What's more, ELFN1-AS1 was uncovered to act as a competing endogenous RNA (ceRNA) to decrease miR-191-5p expression, thus raising special AT-rich sequence-binding protein 1 (SATB1), a downstream target of ceRNA. To sum up, ELFN1-AS1 drives colon cancer cells to proliferate and invade through adjusting the miR-191-5p/SATB1 axis. The above results disclose that lncRNA ELFN1-AS1 is possibly a novel treatment target for colon cancer cases.

FOXA1 Suppresses SATB1 Transcription and Inactivates the Wnt/β-Catenin Pathway to Alleviate Diabetic Nephropathy in a Mouse Model

OBJECTIVE

Diabetic nephropathy (DN) represents the most common diabetic complication that may lead to end-stage renal disease. This work focused on the effect of FOXA1 on the DN development and the molecular mechanism.

METHODS

A mouse model of DN was induced by high-fat diets and streptozotocin. The concentrations of blood glucose and urinary protein in mice, and the pathological changes in mouse kidney tissues were determined. A podocyte cell line MPC-5 was treated with high glucose (HG) to mimic a DN-like condition in vitro. FOXA1 and SATB1 were overexpressed in HG-treated MPC-5 cells and in DN mice to explore their effects on cell proliferation and apoptosis, and on pathological changes in mouse kidney tissues. The binding relationship between FOXA1 and STAB1 was predicted and validated. Activation of the Wnt/β-catenin pathway was detected.

RESULTS

FOXA1 was poorly expressed in the kidney tissues of DN mice. Overexpression of FOXA1 reduced the concentrations of fasting blood glucose and 24-h urinary protein in mice. It also suppressed the accumulation of glomerular mesangial matrix and hyperplasia of glomerular basement membrane, and reduced collagen deposition and interstitial fibrosis in mouse kidney. Also, FOXA1 reduced HG-induced apoptosis of MPC-5 cells. FOXA1 bound to the promoter region of SATB1 for transcription suppression. Overexpression of SATB1 activated the Wnt/β-catenin pathway and blocked the protective roles of FOXA1 in DN mice and in HG-treated MPC-5 cells.

CONCLUSION

This study demonstrated that FOXA1 transcriptionally suppresses SATB1 expression and inactivates the Wnt/β-catenin signaling pathway, thereby inhibiting podocyte apoptosis and DN progression.

HER2, NF-κB, and SATB1 Expression Patterns in Gastric Cancer and Their Correlation with Clinical and Pathological Parameters

Gastric cancer (GC) is currently recognized as one of the most common and fatal tumor worldwide. The identification of novel biomarkers in relation to clinical information as well as extending the knowledge on a multiple crosstalk between various oncogenic pathways implicated in GC carcinogenesis seems pivotal to limit the disease-associated mortality. Therefore, we assessed the expression of HER2, NF-κB, and SATB1 in a total of 104 gastric adenocarcinomas and 30 normal gastric samples and correlated the expression patterns with each other and with some clinicopathological variables. Protein expression was examined by immunohistochemistry (IHC) on tissue microarrays (TMAs), and fluorescence in situ hybridization (FISH) was employed to detect HER2 amplification. In the studied group, HER2 and SATB1 were found to be overexpressed in gastric cancer tissue in comparison to normal gastric mucosa. The expression status of the former protein was seen to differ according to some clinicopathological features, but without statistical significance, whereas the expression of the latter was not importantly associated with any of them. In turn, the NF-κB protein level was significantly related to the presence of lymph node metastasis. HER2 expression was not significantly correlated with that of other proteins, but a positive correlation was found between the expression of SATB1 and NF-κB. Further studies with a larger group of patients combined with in vitro mechanistic experiments are required to fully elucidate the role and relationship of HER2, NF-κB, and SATB1 expression in gastric cancer progression. However, to the best of our knowledge, this study is the first look at a simultaneous evaluation of these three markers in the samples of gastric cancer patients.

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.

SATB family chromatin organizers as master regulators of tumor progression

SATB (Special AT-rich binding protein) family proteins have emerged as key regulators that integrate higher-order chromatin organization with the regulation of gene expression. Studies over the past decade have elucidated the specific roles of SATB1 and SATB2, two closely related members of this family, in cancer progression. SATB family chromatin organizers play diverse and important roles in regulating the dynamic equilibrium of apoptosis, cell invasion, metastasis, proliferation, angiogenesis, and immune modulation. This review highlights cellular and molecular events governed by SATB1 influencing the structural organization of chromatin and interacting with several co-activators and co-repressors of transcription towards tumor progression. SATB1 expression across tumor cell types generates cellular and molecular heterogeneity culminating in tumor relapse and metastasis. SATB1 exhibits dynamic expression within intratumoral cell types regulated by the tumor microenvironment, which culminates towards tumor progression. Recent studies suggested that cell-specific expression of SATB1 across tumor recruited dendritic cells (DC), cytotoxic T lymphocytes (CTL), T regulatory cells (Tregs) and tumor epithelial cells along with tumor microenvironment act as primary determinants of tumor progression and tumor inflammation. In contrast, SATB2 is differentially expressed in an array of cancer types and is involved in tumorigenesis. Survival analysis for patients across an array of cancer types correlated with expression of SATB family chromatin organizers suggested tissue-specific expression of SATB1 and SATB2 contributing to disease prognosis. In this context, it is pertinent to understand molecular players, cellular pathways, genetic and epigenetic mechanisms governed by cell types within tumors regulated by SATB proteins. We propose that patient survival analysis based on the expression profile of SATB chromatin organizers would facilitate their unequivocal establishment as prognostic markers and therapeutic targets for cancer therapy.