Special AT-rich Sequence Binding Protein 1 Expression Research Articles

SATB2 is a supportive marker for the differentiation of a primary mucinous tumor of the ovary and an ovarian metastasis of a low-grade appendiceal mucinous neoplasm (LAMN): A series of seven cases

The differentiation between a primary mucinous ovarian neoplasm and an extra-ovarian metastasis in the ovary is often challenging in the histopathologic practice. Among various ovarian metastases from the gastro-intestinal tract the low-grade appendiceal mucinous neoplasm (LAMN) is an important differential diagnosis to consider particularly in case of pseudomyxoma peritonei. A newly recognized marker in the routine diagnostic of a mucinous neoplasm in the ovary is SATB2 (Special AT-rich sequence-binding protein 2). The expression of SATB2 is, within cells of epithelial lineages, mainly restricted to the lower gastro-intestinal tract, indicating colorectal or appendiceal cancer origin. We report seven cases of LAMN, which clinically became apparent due to ovarian metastases in context of pseudomyxoma peritonei or at least small foci of peritoneal tumor spread. An immunohistochemical marker-panel including SATB2, CDX2, CK20, CK7, PAX8, ER and PR revealed a strong expression of SATB2 in all seven cases. On the contrary SATB2-negativity could be demonstrated in the 40 cases of mucinous borderline tumors and primary mucinous carcinomas of the ovary. The histopathologic tentative diagnosis of an ovarian metastasis of LAMN could be confirmed in the findings of the Appendix in six of seven cases. This report supports SATB2 as an additional diagnostic marker for the diagnosis of an ovarian manifestation of LAMN.

Elevated expression of SATB1 is involved in pancreatic tumorigenesis and is associated with poor patient survival.

Special AT-rich sequence-binding protein 1 (SATB1) is a master chromatin organizer which has been reported to be implicated in tumor progression in breast and lung cancer. However, its functions in pancreatic tumorigenesis have yet to be elucidated. In the present study, the involvement of SATB1 in pancreatic cancer development was investigated in human BxPC-3 pancreatic adenocarcinoma cells. Short hairpin (sh)RNA was used to stably downregulate SATB1 expression, and functional assays, including cell proliferation, colony formation, soft agar and migration assays, were performed in vitro. In addition, a mouse pancreatic cancer xenograft model was created to examine the tumor-promoting properties of SATB1 in vivo. The present findings demonstrated that stable knockdown of SATB1 expression inhibited the proliferation, colony formation, anchorage-independent growth and suppressed the migratory capabilities of BxPC-3 cells in vitro. In addition, SATB1 downregulation significantly inhibited tumor growth in xenografted mice in vivo. Furthermore, SATB1 was revealed to be upregulated in human pancreatic cancer tissue samples compared with matched non-cancerous adjacent tissues, and high SATB1 expression was associated with poor patient survival. Overall, the present study demonstrated that SATB1 promoted the proliferation of pancreatic cancer cells in vitro. In addition, SATB1 expression was revealed to be upregulated in human pancreatic cancer tissues and its upregulation was associated with poor patient survival. Therefore, SATB1 may have potential as a novel prognostic biomarker and therapeutic target for the treatment of patients with pancreatic cancer.

High expression of special AT-rich sequence binding protein-1 predicts esophageal squamous cell carcinoma relapse and poor prognosis.

Previous studies of the roles of special AT-rich sequence binding protein-1 (SATB1) in the development and progression of cancer have suggested that SATB1 promotes cancer cell metastasis. The aim of the present study is to evaluate the role of SATB1 in the progression and prognosis of esophageal squamous cell carcinoma (ESCC). ESCC tissues were collected from 102 patients and SATB1 mRNA expression was measured by reverse transcription-quantitative polymerase chain reaction. The association between expression of SATB1 mRNA with clinicopathological features and prognosis was assessed, and the prognosis of ESCC was evaluated using Kaplan-Meier survival curves. In the 102 ESCC tissues, SATB1 mRNA expression correlated with the clinical tumor node metastasis stage (P<0.05), but not with any other clinicopathological features (including age, gender, tumor differentiation grade, adjuvant radio/chemotherapy, or the consumption of alcohol and use of cigarettes) (P>0.05). The disease-free survival (DFS) and overall survival (OS) of patients with high SATB1 expression was decreased compared with those with low SATB1 expression. The present study indicated that SATB1 mRNA expression was associated with the postoperative recurrent and poor prognosis in ESCC. SATB1 may be a novel marker for predicting the recurrent and worse prognosis of ESCC.

Expression and localization of special AT-rich sequence binding protein 2 in murine molar development and the pulp-dentin complex of human healthy teeth and teeth with pulpitis.

Special AT-rich sequence binding protein 2 (SATB2) is a member of the special family of AT-rich binding transcription factors and has a critical role in osteoblast differentiation and craniofacial patterning. However, the expression and distribution of SATB2 in tooth development is largely unknown. The aim of the present study was to detect the expression and distribution of SATB2 during murine molar development and, in human healthy teeth and teeth with pulpitis using immunohistochemistry. Molars were obtained from Kunming mice at embryonic day (E) 13.5, E14.5, E16.5 and E18.5, and postnatal day (P) 1, P5 and P7. In addition, 20 human teeth (10 healthy and 10 teeth with pulpitis) were obtained from young adult patients (age, 24.90±1.65 years) who were scheduled for routine extraction. Immunohistochemical analyses were performed to detect the expression and distribution of SATB2. The present results revealed that SATB2 exhibits a spatiotemporal expression pattern in murine molar development and was expressed in odontoblasts, predentin, dental pulp cells and the blood vessels in human teeth. These findings suggested that SATB2 may have an important role in odontoblast differentiation and dentin matrix mineralization during tooth development.

Expression and clinical significance of SATB1 and TLR4 in breast cancer.

This study investigated the expression of special AT-rich sequence-binding protein 1 (SATB1) and toll-like receptor 4 (TLR4) protein in breast cancer and its clinical significance. We collected breast cancer tissues from 120 patients and adjacent non-cancerous tissue from 53 patients. SATB1 was expressed in 89 cases of breast cancer (74.17%) and in 7 cases of adjacent non-cancerous tissue (13.21%). TLR4 was expressed in 70 cases of breast cancer tissues (58.33%) and in 48 cases of adjacent non-cancerous tissue (90.57%). The differences of SATB and TLR4 in breast cancer and adjacent non-cancerous tissue were statistically significant. We found a negative correlation between the expression of SATB1 and TLR4 (r=−0.624, P<0.05). The expression of SATB1 and TLR4 were not significantly correlated with age, menopause, and PR and HER-2 protein expression, but were significantly correlated with tumor size, local lymphatic metastasis, histopathological grade, tumor stage, and ER protein expression (P<0.05). Overall, SATB1 and TLR4 proteins are involved in the development of breast cancer, a finding of great significance to identify therapeutic targets and prognosis markers for breast cancer.

SATB2 suppresses non-small cell lung cancer invasiveness by G9a.

Special AT-rich sequence-binding protein 2 (SATB2) is a transcription factor, which plays an important role in transcriptional regulation and chromatin recombinant by combining with matrix attachment regions. More evidence shows that SATB2 is involved in progression of breast cancer, head and neck squamous cell carcinomas and osteosarcoma. However, the role of SATB2 in cancer initiation and progression is still not well understood. Our study identified that decreased expression of SATB2 was correlated with tumor progression and poor prognosis in non-small cell lung cancer (NSCLC) patients. Furthermore, SATB2 suppressed lung cancer cell invasion and metastasis and regulated the expression of EMT-related proteins and histone methylation by G9a. In summary, SATB2 may act as a tumor suppressor gene in NSCLC.

SATB1 promotes epithelial-mesenchymal transition and metastasis in prostate cancer.

Special AT-rich sequence-binding protein-1 (SATB1) is associated with cancer progression and poor clinical outcome. The present study aims to evaluate whether SATB1 affects the biological behaviors of prostate cancer (PCa), and furthermore, to elucidate whether this effect works through the epithelial-mesenchymal transition (EMT) pathway. Firstly, the expression of SATB1 was investigated in a series of PCa tissues as well as in a panel of PCa cell lines. Cell proliferation, migration and invasion were evaluated in SATB1 knockdown and overexpressed PCa cell lines by MTT and Transwell assays. The results showed that the expression of SATB1 was markedly upregulated in PCa tissues and all PCa cell lines (P<0.001). Ectopic expression of SATB1 promoted PCa cell proliferation and migration. Knockdown of SATB1 repressed the ability of cell proliferation and migration of PCa cells. In addition, inhibition of SATB1 could reverse the EMT processes through upregulation of E-cadherin and downregulation of vimentin. The present study provided evidence that SATB1 may act as a potential therapeutic target in PCa patients.

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

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

SATB1 Expression Helps in Identification of the Lymphoid-Lineage-Biased Trajectory of Functionally Fluctuating Hematopoietic Stem Cells

Hematopoietic stem cells (HSCs) are purified well using a combination of surface markers. However, even highly enriched HSC fractions have heterogeneity in their self-renewal and differentiation potential. These seemingly contradictory roles are well regulated according to the changing demand for blood cells. Hence, interactions among lineage-related genes need to be set up, as their differentiation potential is restricted. However, how the functional diversity of HSCs reflects their intrinsic gene expression is not yet known.We previously identified special AT-rich sequence binding protein 1 (SATB1), a global chromatin organizer, as a lymphoid-inducing gene in HSCs (Immunity 2013). SATB1 overexpression strongly enhanced lymphopoiesis from murine HSCs, whereas SATB1 deficiency caused HSC malfunctions. Furthermore, another report showed that SATB1-deficient HSCs were less quiescent and differentiated preferentially to myeloid-erythroid lineages (Nat Immunol 2013). These results suggested that SATB1 is indispensable not only for the lymphopoietic potential but also for the normal function of HSCs.In this study, we first prepared hematological-lineage restricted SATB1 conditional knock out (cKO) mice to examine whether SATB1 is essential for normal HSC function in the adult bone marrow (BM). We crossed SATB1-flox mice with Cre-recombinase expressing mice under control of the Tie2 gene promoter, which efficiently inactivated the target gene in HSCs. Analyzing the BM in these mice, we observed a significant decrease in the number of HSCs as compared to those in their wild type (WT) littermates. Next, we collected HSCs from WT and Tie2-Cre SATB1-flox cKO mice using flow cytometry, and transplanted these CD45.2+ HSCs into CD45.1+ congenic mice. The chimerism of the transplanted cells was lower in recipients of SATB1 cKO mice-derived HSCs. Evaluation of the lymphocytic potential in a co-culture with MS5 stromal cells revealed that the output of lymphocytes from SATB1-cKO HSCs was lower than that of WT HSCs.Secondly, we generated SATB1 reporter mice in which SATB1 expression can be precisely monitored in vivo, and examined the early differentiation of HSCs. We found that the HSC fraction of adult BM consists of SATB1− and SATB1+ cells. We sorted the two types of HSCs with high purity and compared their growth and differentiation potential in vitro and in vivo. In methylcellulose colony assays, SATB1+ HSCs were less potent for producing myeloid-erythroid lineage colonies. In the co-culture with MS5 stromal cells, the output of lymphocytes from SATB1+ HSCs was more robust than that from SATB1− HSCs. RNA-sequencing data showed that the expression of many lymphocyte-related genes was upregulated in the SATB1+ HSCs compared to that in the SATB1− HSCs; however, there were no significant differences between the expression of stem cell-related genes in the two HSC types. In serial transplantation experiments, the SATB1+ HSCs produced more lymphocytic cells and fewer myeloid cells in the first recipients. Moreover, both types of HSCs could equally reconstitute the complete HSC fraction that contained SATB1− and SATB1+ cells, and successfully reconstituted lympho-hematopoiesis in the secondary recipients.In a study with SATB1-cKO mice, we found that SATB1 is indispensable for the preservation of the HSC potential for self-renewing proliferation and lymphocyte-differentiation. These results suggest that SATB1 plays a critical role for HSC integrity. With the newly generated SATB1 reporter mice, we confirmed the heterogeneity of HSCs. While the SATB1− and SATB1+ HSCs significantly differed in lineage-differentiation potential, both showed high long-term self-renewing capacity and reciprocal reconstitution in the serial transplantation. The cell dividing flow of the two HSC fractions settled in the same trajectory in the primary recipients, and then demonstrated equal ability for self-renewal and differentiation in the secondary recipients.Thus, we successfully isolated authentic lymphoid lineage-biased HSCs using SATB1 expression levels, and our results shed light on the oscillating nature of HSCs. Therefore, we conclude that the SATB1 expression demonstrates the fluctuation of HSCs with respect to the lineage-differentiation potential, and that SATB1 probably contributes to generation of chromatin loop formation, which endows HSCs with robust lymphopoietic potential. DisclosuresDoi:Yakult Honsha Co.,Ltd.: Speakers Bureau. Yokota:SHIONOGI & CO., LTD.: Research Funding. Shibayama:Novartis Pharma: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Takeda: Speakers Bureau; Chugai Pharmaceutical: Speakers Bureau; Ono Pharmaceutical: Speakers Bureau. Kanakura:Chugai Pharmaceutical: Research Funding; Eisai: Research Funding; Astellas: Research Funding; Toyama Chemical: Research Funding; Fujimotoseiyaku: Research Funding; Kyowa Hakko Kirin: Research Funding; Shionogi: Research Funding; Alexionpharma: Research Funding; Pfizer: Research Funding; Bristol Myers: Research Funding; Nippon Shinyaku: Research Funding.

SATB1 promotes the malignant of human non-Hodgkin lymphoma by activating the ribonucleotide reductase small subunit M2

To explore the role of the special AT rich sequence binding protein-1 (SATB1) and ribonucleotide reductase M2 (RRM2) in enhancing malignant progression of non-Hodgkin lymphoma (NHL). Methods: A total of 42 NHL and 42 chronic lymphadenitis patients were recruited. The protein expressions of SATB1 and RRM2 in cervical lymph nodes were determined by Western blot. After overexpression of SATB1, siSATB1 or siRRM2, the mRNA levels of SATB1 and RRM2 in cells were analyzed via RT-PCR, the cell proliferation was evaluated via MTT and EdU assays, while the migration and invasion of cells were assessed by transwell assays. Results: Compared with chronic lymphadenitis, the expressions of SATB1 and RRM2 in NHL patients were up-regulated. There was positive correlation between SATB1 and RRM2 in NHL patients. RRM2 mRNA level was up-regulated after transfection of SATB1 and down-regulated after transfection of siSATB1. Overexpression of SATB1 increased tumor cell proliferation, migration and invasion, while knockdown of RRM2 reversed those phenomena. Conclusion: SATB1 functions as an oncogene and promotes tumor cell proliferation, migration and invasion by up-regulation of RRM2 in NHL.

Special AT-rich Sequence-binding Protein 1 (SATB1) Functions as an Accessory Factor in Base Excision Repair

Base excision repair is initiated by DNA glycosylases that recognize specific altered bases. DNA glycosylases for oxidized bases carry both a glycosylase activity that removes the faulty base and an apyrimidinic/apurinic lyase activity that introduces a single-strand DNA incision. In particular, the CUT domains within the CUX1 and CUX2 proteins were recently shown to interact with the 8-oxoguanine (8-oxoG) DNA glycosylase and stimulate its enzymatic activities. SATB1, which contains two CUT domains, was originally characterized as a T cell-specific genome organizer whose aberrant overexpression in breast cancer can promote tumor progression. Here we investigated the involvement of SATB1 in DNA repair. SATB1 knockdown caused a delay in DNA repair following exposure to H2O2, an increase in OGG1-sensitive oxidized bases within genomic DNA, and a decrease in 8-oxoG cleavage activity in cell extracts. In parallel, we observed an increase in phospho-CHK1 and γ-H2AX levels and a decrease in DNA synthesis. Conversely, ectopic expression of SATB1 accelerated DNA repair and reduced the levels of oxidized bases in genomic DNA. Moreover, an enhanced GFP-SATB1 fusion protein was rapidly recruited to laser microirradiation-induced DNA damage. Using purified proteins, we showed that SATB1 interacts directly with OGG1, increases its binding to 8-oxoG-containing DNA, promotes Schiff base formation, and stimulates its glycosylase and apyrimidinic/apurinic lyase enzymatic activities. Structure/function analysis demonstrated that CUT domains, but not the homeodomain, are responsible for the stimulation of OGG1. Together, these results identify another CUT domain protein that functions both as a transcription factor and an accessory factor in base excision repair.

MiR-31 inhibits migration and invasion by targeting SATB2 in triple negative breast cancer

Metastasis is the leading cause of death among breast cancer (BCa) patients and triple negative breast cancer (TNBC) as one of BCa subtypes exhibits the worst survival rate due to its highly aggressive and metastatic behavior. A growing body of research has shown that the dynamic expression of microRNAs (miRNAs) was intimately associated with tumor invasion and metastasis. Recent studies have demonstrated miR-31 as a metastasis-suppressor in breast cancer, but it is still known little about the mechanism of it suppresses metastasis. The special AT-rich sequence-binding protein-2 (SATB2) has been reported to involve in tumor proliferation and invasion, but its function and relationship with miR-31 in breast cancer is still unknown. Here we found that the expression of miR-31 was downregulated in TNBC tissue and cell line. MiR-31 expression was increased after MDA-MB-231 cell was treated by 5-aza-2′-deoxycytidine (5-AZA-CdR), enhance the expression of miR-31 significantly inhibited MDA-MB-231 cell migration and invasion, downregulation of miR-31 expression could promoted MCF-7 cell migration and invasion. The expression of SATB2 was negatively correlated with miR-31 and was upregulated in MCF-7 and MDA-MB-231. Silencing SATB2 expression significantly inhibited MCF-7 and MDA-MB-231 cell proliferation, migration and invasion. Luciferase reporter assays indicated SATB2 is a direct target of miR-31. Taken together, these results suggest miR-31 inhibited TNBC cells migration and invasion through suppressing SATB2 expression.

SATB1 promotes prostate cancer metastasis by the regulation of epithelial-mesenchymal transition.

Special AT-rich sequence binding protein 1 (SATB1) plays important role in the regulation of chromatin structure and gene expression. Recent studies have indicated oncogenic role of SATB1. However, the function of SATB1 in prostate cancer progression and metastasis remains unclear. In this study SATB1 expression vector or siRNA was employed to modulate the expression level of SATB1 in prostate cancer cells and xenograft tumor in nude mouse model. Immunohistochemical analysis was performed on clinical prostate cancer samples. Silencing SATB1 inhibited the growth of DU-145 cells subcutaneous tumor in nude mice, while SATB1 overexpression promoted the growth of LNCaP cells subcutaneous tumor in nude mice. Immunohistochemical and Western blot analysis of the xenografts showed that silencing SATB1 led to decreased expression of vimentin and MMP2 and increased expression of E-cadherin, while SATB1 overexpression led to increased expression of vimentin and MMP2 and decreased expression of E-cadherin. Furthermore, SATB1, vimentin and MMP2 expression was increased significantly while E-cadherin expression was reduced significantly in clinical samples of prostate carcinoma with metastasis compared to prostate carcinoma without metastasis and benign prostate hyperplasia. Taken together, these findings suggest that the modulation of epithelial-mesenchymal transition by SATB1 may contribute to prostate cancer metastasis.

SATB2 expression increased anchorage-independent growth and cell migration in human bronchial epithelial cells

The special AT-rich sequence-binding protein 2 (SATB2) is a protein that binds to the nuclear matrix attachment region of the cell and regulates gene expression by altering chromatin structure. In our previous study, we reported that SATB2 gene expression was induced in human bronchial epithelial BEAS-2B cells transformed by arsenic, chromium, nickel and vanadium. In this study, we show that ectopic expression of SATB2 in the normal human bronchial epithelial cell-line BEAS-2B increased anchorage-independent growth and cell migration, meanwhile, shRNA-mediated knockdown of SATB2 significantly decreased anchorage-independent growth in Ni transformed BEAS-2B cells. RNA sequencing analyses of SATB2 regulated genes revealed the enrichment of those involved in cytoskeleton, cell adhesion and cell-movement pathways. Our evidence supports the hypothesis that SATB2 plays an important role in BEAS-2B cell transformation.

SATB1 is Correlated with Progression and Metastasis of Breast Cancers: A Meta-Analysis

Background/Aims: Several researches have evaluated the significance of SATB1 (Special AT-rich sequence binding protein 1) expression in breast cancers (BCs), but the results have been disputed, especially in the aspects of clinicopathological features and prognosis. Therefore, our study aimed to use a meta-analysis to summarize the clinical and prognostic relevance of SATB1 gene expression in BCs. Methods: A literature search of PubMed, EMBASE, Cochrane library, Chinese Wanfang and CNKI was performed to identify eligible studies. Ten studies total, comprising 5,185 patients (1,699 SATB1-positive and 3,486 SATB1-negative), were enrolled in our study, which was performed using Revman5.3 Software and Stata11.0 Software. Results: This meta-analysis showed that the expression of SATB1 was significantly higher in breast cancer than in normal tissues (OR = 12.28; 95%CI = 6.01-25.09), and was statistically related to several clinicopathological parameters, including lymph node metastasis (OR = 1.55, 95%CI = 1.01-2.39) and Tumor Node Metastasis(TNM) stage (OR = 0.35, 95%CI = 0.22-0.56). However, the level of SATB1 was not statistically associated with the age (OR = 1.13, 95%CI = 0.87-1.46), tumour size (OR = 0.72, 95%CI = 0.44-1.19), estrogen receptor (OR = 0.78, 95%CI = 0.55-1.09), progesterone receptor (OR = 0.64, 95%CI = 0.32-1.29), HER2 status (OR=1.98, 95%CI = 0.74-5.30), and histological type (OR = 0.49, 95%CI = 0.22-1.11). Conclusion: High expression of SATB1 was significantly correlated with tumourigenesis and metastasis of BCs, indicating poor prognosis for patients. SATB1 could serve as a potential marker for detection and prognosis evaluation of breast cancers.

Downregulation of SATB1 increases the invasiveness of Jurkat cell via activation of the WNT/β-catenin signaling pathway in vitro.

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. Many studies suggest that SATB1 overexpression is an indicator of poor prognosis in various cancers, such as breast cancer, malignant cutaneous melanoma, and liver cancer. However, their expression patterns and function values for adult T cell leukemia (ATL) are still largely unknown. The aim of this study is to examine the levels of SATB1 in ATL and to explore its function and mechanisms in Jurkat cell line. Here, we reported that SATB1 expressions were decreased in ATL cells (p < 0.001) compared with normal controls. Knockdown of SATB1 expression significantly enhanced invasion of Jurkat cell in vitro. Furthermore, knockdown of SATB1 gene enhances β-catenin nuclear accumulation and transcriptional activity and thus may increase the invasiveness of Jurkat cell through the activation of Wnt/β-catenin signaling pathway in vitro.

Downregulation of SATB1 Increase the Invasiveness of Jurkat Cell Via Activation of the WNT/Beta-Catenin Signaling Pathway in Vitro

Backgroud: 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. Many studies suggest that SATB1 overexpression is an indicator of poor prognosis in various cancers, such as breast cancer, malignant cutaneous melanoma, liver cancer, etc. However, their expression patterns and function values for adult T-cell leukemia (ATL) are still largely unknown. Objective: The aim of this study is to examine the levels of SATB1 in ATL and to explore its function and mechanisms in ATL.METHODS: 20 ATL peripheral blood samples and 20 normal controls were collected. Expressions of SATB1 in both groups were evaluated by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Cellular proliferation and invasion of SATB1-knockdown Jurkat cells and cells in control group were evaluated by manually count and transwell matrigel invasion assay, respectively.RESULTS: SATB1 expressions were decreased in ATL peripheral blood mononuclear cells (p<0.001) compared with normal controls. Knockdown of SATB1 gene might increase Jurkat cell invasiveness through the activation of Wnt/β-Catenin signaling pathway.CONCLUSIONS: SATB1 expression is down-regulated in ATL and decreased expression of SATB1 increase the invasiveness of Jurkat cell through the activation of Wnt/β-Catenin signaling pathway in vitro.Acknowledgments This study was supported by grants from the National Natural Science Foundation of China (81200399) and Key Clinical Disciplines of Guangdong Province (20111219) DisclosuresNo relevant conflicts of interest to declare.

SATB1 Expression Marks Lymphoid-Lineage-Biased Hematopoietic Stem Cells in Mouse Bone Marrow

Background: Lifelong hematopoiesis is maintained by cell differentiation in which signaling pathways and transcription factors coordinately induce step-wise maturation of hematopoietic stem cells (HSCs) toward downstream effector cells. In addition, the organization of chromatin structure that creates accessible sites of target genes is also essential so as to ensure temporally and spatially adequate control of internal gene expression. Murine HSCs can be isolated with high efficiency using surface molecules including lineage-related markers, c-Kit, Sca-1, Flt3 and SLAM family proteins. However, even the highly enriched HSC fraction is still heterogeneous regarding differentiation potential, and how the HSC diversity reflects the heterogeneity of intrinsic gene-expression in HSCs is as-yet-unknown. We previously identified Special AT-rich Sequence Binding protein 1 (SATB1), a global chromatin regulator, as a lymphoid-related gene in the HSC differentiation (Satoh and Yokota et al. Immunity 2013). Indeed, SATB1 overexpression strongly enhanced both T and B lymphopoietic potential of murine HSCs whereas SATB1 deficiency caused malfunctions of HSCs in the lymphopoietic activity. Furthermore, another report showed that SATB1-deficient HSCs were less quiescent in transplanted recipients and more prone to differentiate preferentially to myeloid-erythroid lineages (Will et al. Nat Immunol 2013). These results suggested that SATB1 is likely indispensable not only for the lymphopoietic potential but also for the integrity of HSCs. Here, to better understand the mechanism how SATB1 influences homeostatic HSC functions in adult bone marrow (BM), we have developed a new mouse model in which SATB1 expression can be precisely monitored along the HSC differentiation.Methods: The Tomato gene, coding a red fluorescent protein, was knock-in to the coding region of endogenous Satb1 gene. The heterozygous SATB1/Tomato knock-in mice in which one Satb1 allele was replaced with the Tomato were used to sort HSCs in adult BM. The sorted cells were evaluated for the differentiation potential with methylcellulose colony assays and co-cultures with MS5 stromal cells. Further, the long-term reconstitution ability was evaluated by transplantation to lethally irradiated mice. To obtain transcriptome information, total RNA was isolated from SATB1/Tomato- and SATB1/Tomato+ HSCs, and then next-generation sequencing was performed. The data were analyzed with the Ingenuity Pathway Analysis software.Results: We defined Lin- Sca1+ c-KitHi (LSK) CD150+ Flt3- cells as HSCs, especially adopting FLT3- to exclude FLT3+ lymphoid-primed multipotent progenitors from our functional analyses. We found that the LSK CD150+ Flt3- fraction contains substantial number of SATB1/Tomato+ cells. While both SATB1/Tomato- and SATB1/Tomato+ HSCs produced numerous CFU-Mix and CFU-GM/G/M colonies, the latter were less potent to produce BFU-E. In co-culture with MS5 stromal cells that support B and myeloid lineages, the output of B lineage cells from SATB1+ HSCs was more robust than that of SATB1- HSCs. Upon transplantation, enhanced B-lineage engraftment was observed in the SATB1+ HSC-transplanted recipients. Interestingly, while the two types of HSCs showed obvious difference in the differentiation potential toward lymphoid or myeloid lineage, both HSCs reconstituted the LSK CD150+ Flt3- fraction that similarly contained SATB1/Tomato- and SATB1/Tomato+ cells. With the RNA-sequencing data of SATB1- and SATB1+ HSCs, biological pathway analyses revealed that the "Hematological System Development and Function" pathway was remarkably up-regulated in the SATB1+ HSCs. Among subcategories of the "Hematological System Development and Function" pathway, the "quantity of lymphocytes" pathway was increased whereas "quantity of myeloid cells" and "quantity of granulocytes" pathways were decreased.Conclusion: We have developed a new mouse system that can be used to identify and isolate viable lymphoid-biased HSCs in the most primitive hematopoietic cell fraction of adult BM. While the SATB1- and SATB1+ HSCs differ genetically and functionally, both subtypes have displayed a self-renewal activity with mutual interconversion in transplanted recipients. These findings suggest that functional heterogeneity and variability within the HSC population is, at least in part, a manifestation of SATB1 expression. DisclosuresYokota:SHIONOGI & CO., LTD.: Research Funding.

SATB1 is a potential therapeutic target in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary malignant tumor of the liver with a poor prognosis. Upregulation of special AT-rich sequence-binding protein 1 (SATB1) promotes tumor progression. However, little is known about the role of SATB1 in ICC tumorigenesis. We firstly investigated the expression of SATB1 in 88 cases of ICC by immunohistochemistry (IHC), QRT-PCR, and western blot. Meanwhile, we constructed stably knockdown (shRNA) of SATB1 in ICC cell lines to evaluate the effects of SATB1 on the ability of cell proliferation and invasion by MTT and transwell invasion assay. Our result showed that SATB1 was overexpressed in ICC tissues samples. Knockdown of SATB1 could inhibit ICC cell proliferation, and suppress ICC cell invasion of ICC cell lines. In addition, the depletion of SATB1 expression suppressed the MYC levels in vitro. Our results highlight the significance of SATB1 in ICC and suggest that SATB1 could be a promising therapy target and a potential biomarker for prognosis in ICC patients.

Special AT-rich sequence binding protein 1 expression correlates with response to preoperative radiotherapy and clinical outcome in rectal cancer

Our recent study showed the important role of special AT-rich sequence binding protein 1 (SATB1) in the progression of human rectal cancer. However, the value of SATB1 in response to radiotherapy (RT) for rectal cancer hasn't been reported so far. Here, SATB1 was determined using immunohistochemistry in normal mucosa, biopsy, primary cancer, and lymph node metastasis from 132 rectal cancer patients: 66 with and 66 without preoperative RT before surgery. The effect of SATB1 knockdown on radiosensitivity was assessed by proliferation-based assay and clonogenic assay. The results showed that SATB1 increased from normal mucosa to primary cancer, whereas it decreased from primary cancer to metastasis in non-RT patients. SATB1 decreased in primary cancers after RT. In RT patients, positive SATB1 was independently associated with decreased response to preoperative RT, early time to metastasis, and worse survival. SATB1 negatively correlated with ataxia telangiectasia mutated (ATM) and pRb2/p130, and positively with Ki-67 and Survivin in RT patients, and their potential interaction through different canonical pathways was identified in network ideogram. Taken together, our findings disclose for the first time that radiation decreases SATB1 expression and sensitizes cancer cells to confer clinical benefit of patients, suggesting that SATB1 is predictive of response to preoperative RT and clinical outcome in rectal cancer.