Special AT-rich Sequence-binding Protein 1 Protein Expression Research Articles

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

Special AT-rich sequence-binding protein 1 (SATB1) is a ‘genome organizer,’ and it has been proposed as a factor that affects the development and progression of various human neoplasms, including colorectal cancer (CRC). This study aimed to compare SATB1 expression in a group of CRC patients and healthy subjects at the mRNA and protein levels. We collected paired tumor tissue and unchanged mucosa of the large intestine from 102 CRC patients as well as 53 biopsies of normal colon mucosa obtained from healthy patients during screening colonoscopy. Tissue samples were quantified for SATB1 mRNA by quantitative PCR, while SATB1 protein expression was determined by Western blotting and immunohistochemistry. SATB1 mRNA level in tumor tissues was over twofolds lower than in samples of corresponding unchanged tissues and fourfolds lower than in biopsies of healthy colon mucosa. Western blotting analysis revealed that SATB1 protein content in tumor and unchanged tissues of CRC patients was over sixfold and fivefolds higher than in biopsies of healthy colon mucosa, respectively. Immunohistochemical staining demonstrated higher nuclear and cytoplasmic SATB1 reactivity in the tumor tissue compared to unchanged mucosa of CRC patients. Despite these differences, SATB1 mRNA, protein, and immunoreactivity levels did not correlate with patients’ clinicopathological data and their overall survival, but the latter analysis was limited by a relatively short period of follow-up. In conclusion, we suggest that some as yet unidentified posttranscriptional mechanisms that regulate SATB1 expression may be altered in the CRC tissue.

Expression and significance of SATB1 in the development of breast cancer.

Special AT-rich sequence binding protein 1 (SATB1) is a recently discovered gene regulator that can promote the growth and metastasis of breast cancer. However, its expression in different stages of breast cancer development have not been examined. We explored the role of SATB1 in the development of breast cancer by detecting SATB1 expression levels in different stages of breast cancer. SATB1 expression was determined using an immunohistochemical streptavidin peroxidase method; the relationship between clinicopathological features of breast cancer and SATB1 expression was analyzed using the X(2) test. Positive rates of SATB1 protein in normal breast tissue, normal breast ductal hyperplasia tissue, precancerous lesions of breast cancer, non-invasive cancer, early invasive carcinoma, and invasive breast cancer tissue were, respectively, 6.25 (2/32), 6.4 (3/47), 20.4 (10/49), 45.0 (9/20), 52.9 (9/17), and 76.6% (72/94). SATB1 in the latter 3 groups was significantly higher than in the first 3 groups (P < 0.05). The positive rate of SATB1 protein in invasive non-special types of breast cancer (88.5%, 54/61) was significantly higher than in the special type of invasive breast cancer (54.5%, 18/33) and early invasive breast cancer (52.9%, 9/17) (P < 0.05). SATB1 protein expression in breast cancer with lymph node metastasis was generally increased, and the difference was statistically significant (P < 0.05). SATB1 protein expression showed an increasing trend in different stages of breast cancer development. Overexpression indicated poor prognosis.

Decreased SATB1 Expression in ALT and Promoted Invasion of Jurkat Cell in Vitro

BACKGROUND: Special AT-rich sequence-binding protein-1 (SATB1) is critical for genome organizer that reprograms chromatin organization and transcription profiles, and associated with tumor growth and metastasis in several cancer types cancer. However, their expression patterns and function values for adult T-cell leukemia (ALT) are still largely unknown.METHODS: Expression of SATB1 in normal and ALT peripheral blood leucocytes (n=50 for normal, n=30 for ALT) were evaluated by RT-qPCR in mRNA level. Expression of protein SATB1 in leukemia cell lines were evaluated by Weston Blot.SATB1-shRNA was constructed in psuper-retro-puro retrovirus vector. Jurkat-SATB1-sh and control stable cell lines were established after virus infection and puromycin selection. Cellular proliferation and invasion of Jurkat-ctr and SATB1 knockdown Jurkat cells were evaluated by CCK-8 kit and transwell matrigel invasion assay, respectively.RESULTS: SATB1 mRNA expression was decreased in ALT (p<0.001) compared with normal peripheral blood leucocytes cells. SATB1 protein expression in Jurkat cell was higher than other leukemia cell lines. SATB1-shRNA was constructed successfully. Weston Blot show Jurkat-SATB1-sh and control stable cell lines were established successfully. Knockdown of SATB1 expression significantly enhanced invasion of Jurkat cell in vitro but no effect in proliferationCONCLUSIONS: Decreased expression of SATB1 in ALT was associated with cell invasion. DisclosuresNo relevant conflicts of interest to declare.

Abstract 5199: Distinct expression pattern of microRNAs bioinformatically predicted to target SATB1 in human breast cancer

Abstract Recently, genome organizer protein special AT-rich sequence-binding protein 1(SATB1) has been reported to promote a metastatic phenotype and correlate with poor prognosis in breast cancer. The mechanism of SATB1 elevation in breast cancer remains elusive. This study was to investigate whether microRNAs (miRNAs) play a role in modulating SATB1 expression in ductual breast cancer by using archival formalin-fixed and paraffin-embedded (FFPE) clinical samples. Firstly, four canonical target prediction databases, including TargetScan, PicTar, miRanda and miRDB, were utilized to predict the interaction between miRNA and the 3′-UTR of SATB1 mRNA. The results of the prediction software programs were then integrated by displaying Venn diagram. Secondly, the Qiagen miRNeasy FFPE kit was used to isolate total RNA from 93 specimens with primary invasive ductual breast cancer. Expression of candidate miRNA transcriptional levels was measured using TaqMan MicroRNA Assays with miRNA-specific stem loop primers by relative real-time quantitative RT-PCR. The relative levels of miRNA expression were calculated from the relevant signals by normalization with the signal for RNU6B miRNA expression in each sample. Meanwhile, SATB1 protein expression levels were assessed by immunohistochemistry(IHC). Finally, correlations between the expression levels of these miRNAs and SATB1 were analyzed. Overall 22 miRNAs, 24 miRNAs, 76 miRNAs and 75 miRNAs were found by TargetScan, PicTar, miRanda and miRDB, to target SATB1 respectively, whereas only miR-7, miR-21, miR-23a, miR-23b, miR-34a and miR-155 were found by all four programs to be predicted to regulate SATB1. Quantitative RT-PCR detection analysis showed that expression levels of miR-34a were much higher in SATB1-negative than in SATB1-positive tumors (p&amp;lt;0.001). whereas lower miR-7 expression showed a strong trend toward an association with elevated SATB1 expression (P = 0.056). We then extended the analysis of miR-34a expression in breast cancer tissues to include all scores for SATB1 protein expression, assessed semiquantitatively by IHC. miR-34a expression levels were gradually decreased as SATB1 protein scores increased. Moreove, our quantitative RT-PCR results showed no differences in miR-21, miR-23a, miR-23b, and miR-155 expression between SATB1-negative and SATB1-positive tumors. We thus conclude that SATB1 maybe a novel target of miR-34a in human breast cancer. Downregulation of miR-34a promotes human breast cancer to progress through reduced repression of SATB1. Restoration of miR-34a may prove therapeutic in breast cancer patients in which aberrant SATB1 expression plays a role. Note: This abstract was not presented at the meeting. Citation Format: Weiming Duan, Zixing Chen, Li Yao, Min Tao, Kai Chen, Wei Liu, Jiannong Cen. Distinct expression pattern of microRNAs bioinformatically predicted to target SATB1 in human breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5199. doi:10.1158/1538-7445.AM2014-5199

Loss of special AT‐rich sequence‐binding protein 1 (SATB1) predicts poor survival in patients with colorectal cancer

Special AT-rich sequence-binding protein 1 (SATB1) is a cell type-specific matrix attachment region binding protein, functioning as a global genome organizer. This study aims to investigate the expression pattern and the prognostic value of SATB1 in colorectal cancer. Prospectively collected data were obtained and tissue microarrays were constructed from a cohort of 352 patients. SATB1 protein expression was evaluated by immunohistochemistry and scored by two independent investigators. SATB1 expression was predominantly nuclear in both normal and cancer tissues. Loss of SATB1 nuclear expression was seen in 22% of colorectal cancers compared to 1.5% of adjacent normal colorectal tissue, and was associated with worse overall survival (P=0.02) independent of age and stage of disease (HR 2.48 with 95% CI 1.31-4.70). Loss of SATB1 expression was more evident in younger patients (P=0.03), tumours with mucinous or signet ring histology (P=0.0001) and poor differentiation (P=0.005). SATB1 expression was associated with a survival advantage in patients with Dukes C tumours who received adjuvant chemotherapy. Loss of SATB1 nuclear expression correlates with poor survival and a less favourable response to adjuvant chemotherapy in colorectal cancer. The value of SATB1 in individualized colorectal cancer therapy warrants further evaluation.

Phosphorylated SATB1 is associated with the progression and prognosis of glioma

Special AT-rich sequence-binding protein 1 (SATB1) is a global chromatin organizer and gene regulator, and high expression of SATB1 is associated with progression and poor prognosis in several malignancies. Here, we examine the expression pattern of SATB1 in glioma. Microarray analysis of 127 clinical samples showed that SATB1 mRNA was expressed at lower levels in highly malignant glioblastoma multiforme (GBM) than in low-grade glioma and normal brain tissue. This result was further confirmed by real-time RT-PCR in the clinical samples, three GBM cell lines, primary SU3 glioma cells and tumor cells harvested by laser-capture microdissection. Consistent with the mRNA levels, SATB1 protein expression was downregulated in high-grade glioma, as shown by western blotting. However, phospho-SATB1 levels showed an opposite pattern, with a significant increase in these tumors. Immunohistochemical analysis of phospho-SATB1 expression in tissue microarrays with tumors from 122 glioma cases showed that phospho-SATB1 expression was significantly associated with high histological grade and poor survival by Kaplan–Meier analysis. In vitro transfection analysis showed that phospho-SATB1 DNA binding has a key role in regulating the proliferation and invasion of glioma cells. The effect of SATB1 in glioma cell is mainly histone deacetylase (HDAC1)-dependent. We conclude that phospho-SATB1, but not SATB1 mRNA expression, is associated with the progression and prognosis of glioma. By interaction with HDAC1, phospho-SATB1 contributes to the invasive and proliferative phenotype of GBM cells.

Over-expression of the special AT rich sequence binding protein 1 (SATB1) promotes the progression of nasopharyngeal carcinoma: association with EBV LMP-1 expression

BackgroundSpecial AT rich sequence binding protein 1 (SATB1) plays a crucial role in the biology of various types of human cancer. However, the role of SATB1 in human nasopharyngeal carcinoma (NPC) remains unknown. In the present study, we sought to investigate the contribution of aberrant SATB1 expression in the progression of NPC and its association with the Epstein Barr virus (EBV)-encoded latent membrane protein 1 (LMP-1).MethodsImmunohistochemical analysis was performed to detect SATB1 and LMP-1 protein in clinical samples, and the association of SATB1 protein expression with patient clinicopathological characteristics and LMP-1 expression were analyzed. SATB1 expression profiles were evaluated in well-differentiated NPC cell line CNE1, poorly-differentiated CNE2Z, undifferentiated C666-1 and immortalized nasopharyngeal epithelia NP-69 cells using quantitative RT-PCR, western blotting and fluorescent staining. After inhibition the SATB1 expression by using SATB1 specific small interfering RNA in these cell lines, the change of cell proliferation was investigated by western blotting analysis of PCNA (proliferating cell nuclear antigen) expression and CCK-8 assay, and the cell migration was assessed by Transwell migration assay. Finally, the expressions of SATB1 and PCNA were examined in CNE1 cells that forced LMP-1 expression by fluorescent staining and RT-PCR.ResultsImmunohistochemical analysis revealed that SATB1 protein expression was elevated in NPC tissues compared to benign nasopharyngeal tissues (P = 0.005). Moreover, high levels of SATB1 protein expression were positively correlated with clinical stage (P = 0.025), the status of lymph node metastasis (N classification) (P = 0.018), distant metastasis (M classification) (P = 0.041) and LMP-1 expression status (r = 2.35, P < 0.01) in NPC patients. In vitro experiments demonstrated that an inverse relationship between SATB1 expression and NPC differentiation status, with SATB1 weakly expressed in NP-69 cells and CNE1 cells, and significant increasingly expressed in CNE-2Z and C666-1 cells. Targeted knockdown of SATB1 expression obviously attenuated the proliferation and migration of highly SATB1-expressing CNE2Z and C666-1 cells, but not NP-69 and CNE1 cells. Interestingly, forced LMP-1 expression in CNE1 cells led to a surprisingly increasing SATB1 expression and nuclear location, companying with an up-regulated PCNA expression.ConclusionsOur results reveal that EBV LMP-1-mediated over-expression of SATB1 is associated with NPC progression, suggesting SATB1 may represent a promising biomarker and therapeutic target for NPC.

Correlation of SATB1 overexpression with the progression of human rectal cancer

To date, the association between special AT-rich sequence-binding protein 1 (SATB1) and colorectal cancer (CRC) has not been reported. This study was aimed at investigating the expression and potential role of SATB1 in human rectal cancers. Ninety-three paired samples of rectal cancer and distant normal rectal tissue were analyzed by quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC), and the correlations between SATB1 expression and clinicopathological parameters were evaluated. The expression profiles of SATB1 were also investigated in a panel of five human colon carcinoma cell lines. The general level of SATB1 mRNA in rectal cancer tissues was statistically significantly higher than that in normal mucosa (P = 0.043). The rate of positive SATB1 protein expression in rectal cancers (44.1%) was significantly higher than that in normal tissues (25.8%) by IHC analysis (P = 0.009). Overexpression of SATB1 mRNA was more predominant in patients with earlier onset of rectal cancer (P = 0.033). SATB1 expression correlated with invasive depth and tumor node metastasis (TNM) stage at both protein and mRNA levels (P < 0.05). Furthermore, SATB1 expression in the poorly metastatic KM12C cells was significantly lower than the highly metastatic KM12SM and KM12L4A cells and higher than the HCT116 and SW480 cells (P = 0.001). These results were further confirmed by Western blotting. Our results indicate that SATB1 may play an important role in the progression of human rectal cancer, which represents a possible new mechanism underlying CRC.

Overexpression of SATB1 in Laryngeal Squamous Cell Carcinoma

Objective: To investigate the expression of special AT-rich sequence-binding protein 1 (SATB1), and the relationship between SATB1 and clinicopathological factors of laryngeal squamous cell carcinoma (LSCC). Methods: Real-time PCR, Western blot and immunohistochemistry were used to analyze 80 samples of LSCC and 25 samples of control mucosa. The relationship between SATB1 expression and clinicopathological parameters was evaluated. Results: The SATB1 mRNA expression levels in LSCC were 2.5- to 7.5-fold higher than those in control mucosa tissues (p < 0.001). SATB1 protein expression was detected in approximately 66% (53 out of 80) of the LSCC specimens, whereas it was below the detection limit in all the control mucosa specimens (p < 0.001). The SATB1 mRNA levels in positive cervical lymph nodes, in clinical stages III and IV with poor/moderate cell differentiation, were significantly higher than those in negative cervical lymph nodes in clinical stage II with high cell differentiation (p = 0.022, p = 0.005 and p = 0.006, respectively). Conclusions: SATB1 mRNA and protein levels are elevated in LSCC tissues, and their levels are correlated with clinical stages and differentiation status. The current findings suggest that SATB1 may be a useful marker for the prognosis and assessment of therapeutic effects.