Identification of retinal ganglion cell types expressing the transcription factor Satb2 in three primate species.

In primates, the retinal ganglion cells contributing to high acuity spatial vision (midget cells and parasol cells), and blue-yellow color vision (small bistratified cells) are well understood. Many other ganglion cell types with large dendritic fields (named wide-field ganglion cells) have been identified, but their spatial density and distribution are largely unknown. Here we took advantage of the recently established molecular diversity of ganglion cells to study wide-field ganglion cell populations in three primate species. We used antibodies against the transcription factor Special AT-rich binding protein 2 (Satb2) to explore its expression in macaque (Macaca fascicularis, M. nemestrina), human and marmoset (Callithrix jacchus) retinas. In all three species, Satb2 cells make up a low proportion (1.5-4%) of the ganglion cell population, with a slight increase from central to peripheral retina. Intracellular dye injections revealed that in macaque and human retinas, the large majority (over 80%) of Satb2 cells are inner and outer stratifying large sparse cells. By contrast, in marmoset retina the majority (over 60%) of Satb2 expressing cells were broad thorny cells, with smaller proportions of recursive bistratified (putative direction-selective), large bistratified, and outer stratifying narrow thorny cells. Our findings imply that Satb2 expression has undergone rapid species specific adaptations during primate evolution, because expression is not conserved across Old World (macaque, human) and New World (marmoset) suborders.

Patterns of SATB2 and p16 reactivity aid in the distinction of atypical polypoid adenomyoma from myoinvasive endometrioid carcinoma and benign adenomyomatous polyp on endometrial sampling.

AIMS: Atypical polypoid adenomyoma (APAM) is an uncommon uterine lesion composed of complex endometrioid glands with frequent squamous morular metaplasia and fibromuscular stroma. On endometrial curettage, biopsy or polypectomy specimens, the admixture of endometrioid glands and smooth muscle raises the differential diagnosis of myoinvasive endometrioid carcinoma. Reproductive-age APAM patients may opt for fertility preservation, whereas myoinvasive carcinoma is treated surgically. One previous study reported an incidental finding that the stroma of APAM, in contrast to that of other polypoid lesions, was SATB2-positive. APAM has also been reported to show increased stromal p16 staining. We aimed to assess whether SATB2 and p16 are useful stains for the distinction of APAM from myoinvasive carcinoma and benign adenomyomatous polyps. METHODS AND RESULTS: Cases of 'atypical polypoid adenomyoma' (n = 32), 'adenomyomatous polyp' (n = 39) and 'myoinvasive endometrioid carcinoma' (n = 30) were identified. Morphological features were assessed, along with the intensity and extent of SATB2 and p16 staining in the stromal component of each lesion. SATB2 expression was seen in the stromal components of 30 of 32 (94%) APAMs, versus none of 39 (0%) benign adenomyomatous polyps and five of 30 (17%) myoinvasive endometrioid carcinomas. Stromal p16 expression was seen in 31 of 31 (100%) APAMs, versus 20 of 39 (51%) benign adenomyomatous polyps and 12 of 30 (40%) myoinvasive endometrioid carcinomas. CONCLUSIONS: Patchy to diffuse SATB2 and block-type p16 staining of fibromuscular stroma separating atypical endometrioid glands is more consistent with APAM than with myoinvasive endometrioid carcinoma. These stains are potentially useful adjuncts to careful morphological evaluation of endometrial biopsies/curettings.

lncRNA SNHG8 promotes aggressive behaviors of nasopharyngeal carcinoma via regulating miR-656-3p/SATB1 axis.

BACKGROUND: Long non-coding RNA (lncRNA) has been proposed to regulate tumorigenesis, however, the role of small nucleolar RNA host gene 8 (SNHG8) in nasopharyngeal carcinoma (NPC) remains unclear. METHODS: Levels of SNHG8 in NPC tissues and cells were analyzed with real-time quantitative PCR method. Cell counting kit-8 assay, colony formation assay, wound-healing assay, and transwell invasion assay were performed to detect cell viability, migration, and invasion. Luciferase activity assay and RIP assay were performed to explore relationships among SNHG8, microRNA-656-3p (miR-656-3p), and special AT-rich sequence-binding protein 1 (SATB1). RESULTS: We found SNHG8 level was increased expression in NPC tissues and cells.In vitro assays revealed that SNHG8 stimulates NPC cell proliferation, colony formation, cell migration, and cell invasion. In vivo assay confirmed knockdown of SNHG8 could hamper tumor growth. Furthermore, we showed SNHG8 serves as a sponge for miR-656-3p to regulate SATB1 expression, and participated in NPC progression. CONCLUSIONS: In summary, our work indicated the importance of SNHG8 in NPC progression, which provided novel treatment methods for NPC.

SATB2 is frequently expressed in ossifying and non-ossifying peripheral oral fibroma of the gingival region but not in reactive fibromatous lesions from other intraoral sites.

Ossifying and non-ossifying peripheral oral fibromas (POF) of the gingival and alveolar mucosa are localized, cellular, small fibrous nodular lesions likely resulting from diverse external/ internal physical and chemical irritation or injuries. A central nidus of metaplastic woven bone characterizes and defines the ossifying variant. The inherent tendency of these lesions to ossify remains elusive. We herein analyze SATB2 expression as osteoblastic transcription and differentiation factor in 28 gingival POFs (10 of them ossifying) and compare them to 28 fibrous lesions from different non-gingival intraoral sites. Strong to moderate diffuse nuclear SATB2 immunoreactivity was detected in all ossifying (10/10; 100%) and in 8/18 (44%) non-ossifying gingival POFs, but in only 1/28 (3%) non-gingival oral reactive nodular fibrous lesions. This study illustrates for the first-time consistent expression of the osteoblastic marker SATB2 in ossifying and most of non-ossifying POFs of the gingival area but lack of this marker in reactive fibrous lesions from other oral cavity sites. This finding is in line with the proposed origin of gingival POFs from periodontal ligaments and may explain the frequent ossification observed in them. It is mandatory to consider this finding when assessing biopsies from SATB2-positive oral cavity neoplasms to avoid misinterpretation.

miR-29a-5p Targets SATB2 and Regulates the SIRT1/Smad3 Deacetylation Pathway to Inhibit Thoracic Ligamentum Flavum Cell Osteogenesis.

STUDY DESIGN: Experimental analysis of the thoracic ligamentum flavum cell osteogenic differentiation process. OBJECTIVE: This study aimed to explore the role of miR-29a-5p and special AT-rich sequence-binding protein 2 (SATB2) in a pathological osteogenic process. SUMMARY OF BACKGROUND DATA: Thoracic ossification of the ligamentum flavum (TOLF) is an uncommon disease wherein ligaments within the spine undergo progressive ossification, resulting in stenosis of the spinal canal and myelopathy. MiR-29a-5p was found to be downregulated in ligament cells from ossified ligament tissue in a previous study. However, whether miR-29a-5p is involved in the process of TOLF has not been investigated. METHODS: The expression of miR-29a-5p in ligament tissues or in the context of TOLF osteogenic cell differentiation was measured via qRT-PCR. Alkaline phosphatase activity assay and Alizarin red staining were used to analyze cellular osteogenesis. The protein-level expression of SATB2, SIRT1, and Smad3 were measured via immunohistochemistry or western blotting. Dual luciferase reporter assays and western blotting were used to confirm that miR-29a targets SATB2. RESULTS: SATB2 was found to be upregulated and miR-29a-5p was downregulated in TOLF tissue. We additionally observed decreased miR-29a-5p expression during the process of TOLF osteogenic cell differentiation, and there was a marked reduction in the expression of key mediators of osteogenesis when miR-29a-5p was overexpressed. Consistent with this, when miR-29a-5p was inhibited this led to enhanced osteogenic cell differentiation of these cells. We further found miR-29a-5p to directly target and suppress the expression of SATB2. Knock-down of SATB2 was sufficient to reduce the ability of miR-29a-5p to inhibit osteogenesis, and this also led to decreased SIRT1 expression and Smad3 acetylation. CONCLUSION: Together our findings indicate that miR-29a-5p is able to prevent thoracic ligamentum flavum cell osteogenesis at least in part via targeting SATB2 and thereby suppressing the SIRT1/Smad3 deacetylation pathway. LEVEL OF EVIDENCE: N/A.

CDX2, SATB2, GATA3, TTF1, and PAX8 Immunohistochemistry in Krukenberg Tumors.

Twenty-six Krukenberg tumors (16 lower gastrointestinal, 4 upper gastrointestinal, and 6 of unknown origin) and their primaries when known were stained with CDX2, SATB2, GATA3, TTF1, and PAX8 using a tissue microarray containing predominantly or exclusively signet ring cells. The most common primary was appendiceal mixed adenoneuroendocrine carcinoma. CDX2 and SATB2 were positive in all known lower gastrointestinal primary tumors and negative in nearly all known upper gastrointestinal primary tumors. Primaries showed identical immunophenotypes to their metastases. Among cases of unknown primary origin, 3 were positive and 3 were negative for CDX2 and SATB2. Chest images, upper endoscopies, colonoscopies, appendectomies, and mammogram were performed with negative results in all, 4, 2, 2, and 1 cases, respectively. No cystoscopies were attempted. PAX8, GATA3, and TTF1 were negative in all cases. The literature was reviewed with emphasis on immunohistochemistry of signet ring cell-containing carcinomas from the appendix, colon, stomach, breast, lung, and bladder. Three quarters of gastric primaries stain for CDX2 and only rare examples stain for SATB2. Colorectal primaries (most of them) and appendiceal primaries (all of them) are positive for CDX2 and SATB2. GATA3 stains almost all breast primaries and approximately half of bladder primaries. All pulmonary primaries are positive for TTF1. PAX8 is negative in the gastric, colorectal, and appendiceal primaries reported. This study shows that the panel of immunostains is useful in confirming the site of origin of a metastatic Krukenberg tumor when one is known and has limited diagnostic value for diagnosing metastases of unknown origin.

Maternal regulation of SATB2 in osteo-progeniters impairs skeletal development in offspring.

Nutritional status during intrauterine and/or early postnatal life has substantial influence on adult offspring health. Along these lines, there is a growing body of evidence illustrating that high fat diet (HFD)-induced maternal obesity can regulate fetal bone development. Thus, we investigated the effects of maternal obesity on both fetal skeletal development and mechanisms linking maternal obesity to osteoblast differentiation in offspring. Embryonic osteogenic calvarial cells (EOCCs) were isolated from fetuses at gestational day 18.5 (E18.5) of HFD-induced obese rat dams. We observed impaired differentiation of EOCCs to mature osteoblasts from HFD obese dams. ChIP-seq-based genome-wide localization of the repressive histone mark H3K27me3 (mediated via the polycomb histone methyltransferase, enhancer of zeste homologue 2 [Ezh2]) showed that this phenotype was associated with increased enrichment of H3K27me3 on the gene of SATB2, a critical transcription factor required for osteoblast differentiation. Knockdown of Ezh2 in EOCCs and ST2 cells increased SATB2 expression; while Ezh2 overexpression in EOCCs and ST2 cells decreased SATB2 expression. These data were consistent with experimental results showing strong association between H3K27me3, Ezh2, and SATB2 in cells from rats and humans. We have further presented that SATB2 mRNA and protein expression were increased in bones, and increased trabecular bone mass from pre-osteoblast specific Ezh2 deletion (Ezh2flox/flox Osx-Cre+ cko) mice compared with those from control Cre+ mice. These findings indicate that maternal HFD-induced obesity may be associated with decreasing fetal pre-osteoblastic cell differentiation, under epigenetic control of SATB2 expression via Ezh2-dependent mechanisms.

SATB2 protein expression by immunohistochemistry is a sensitive and specific marker of appendiceal and rectosigmoid well differentiated neuroendocrine tumours.

AIMS: Neuroendocrine neoplasms (NNs) range from well to poorly differentiated and indolent to highly aggressive. The site of origin in metastatic NNs has therapeutic and prognostic implications. SATB2 is a transcriptional regulator involved in osteoblastic and neuronal differentiation and is a sensitive and specific marker of colorectal epithelium. This study aimed to evaluate the expression of SATB2 in NNs from various primary sites and its utility as a marker in determining the site of origin of these neoplasms. METHODS AND RESULTS: SATB2 immunohistochemistry was performed on 266 NNs, including lung small cell carcinomas (n = 39) and carcinoids (n = 30), bladder (n = 21) and prostate (n = 31) small cell carcinomas, and gastrointestinal (GI)/pancreatic NNs of various primary sites (n = 145) consisting of well-differentiated neuroendocrine tumours (WDNET)s (n = 124) and poorly differentiated neuroendocrine carcinomas (PDNEC)s (n = 21). SATB2 was expressed in prostatic (10 of 31, 32%) and bladder (eight of 21, 38%) small cell carcinomas, lung carcinoid tumours (one of 30, 3%), and lung small cell carcinomas (eight of 39, 21%). Among primary GI NNs, SATB2 was expressed in 37 of 124 (30%) WDNETs and four of 21 (19%) PDNECs. Of the former, 15 of 15 (100%) rectal/rectosigmoid and 22 of 22 (100%) appendiceal neoplasms expressed SATB2. Using receiver operator characteristic analysis, SATB2 was a sensitive and specific marker for rectal (100.0%, 80.0%) and appendiceal (100.0%, 84.5%) WDNETs, respectively. CONCLUSIONS: In summary, SATB2 is a sensitive and specific marker for rectal/rectosigmoid and appendiceal WDNETs, and may represent a useful diagnostic tool when these sites of origin are considered in the differential diagnosis.

Hepatitis B Virus X Protein Induces SATB1 Expression Through Activation of ERK and p38MAPK Pathways to Suppress Anoikis.

BACKGROUND: We previously reported that there were potentially certain correlations between the high expression of SATB1 and the HBV infection in human hepatocellular carcinoma tissues, and SATB1 promoted tumor growth and metastasis in liver cancer. Hepatitis B virus (HBV) infection is internationally recognized as a contributing factor to metastasis in liver cancer. The anoikis prevention of detached malignant cancer cells is the precondition for metastasis. AIMS: Our studies aimed to explore the relationship between HBV infection, SATB1 and liver cancer cell anoikis and their specific regulatory mechanisms in HBV-associated liver cancer. METHODS: HepG2 cell was transiently transfected with pBlue-HBV and seven types of HBV-encoded protein plasmids. Anoikis assay and soft agarose colony formation experiment were analyzed in HepG2.2.15-SATB1 siRNA cells, HBx-overexpressing cells and HepG2-HBx-SATB1 siRNA cells. The inhibitors of signaling molecules were used to treat of HepG2-HBx cells, and then, the SATB1 expression and phosphorylation levels of signaling molecules were evaluated. RESULTS: Our data show that the high expression of SATB1 and enhanced anoikis resistance were observed in HBV stably expressing cell line HepG2.2.15 and high metastatic potential cell line SK-HEP-1. HBV can induce SATB1 expression and suppress anoikis of unattached liver cancer cells. Moreover, SATB1 expression and anoikis resistance were mainly regulated by HBV-encoded viral protein HBx through the activation of ERK and p38 MAPK signaling pathways to promote metastasis of liver cancer. CONCLUSION: These data suggest that the HBV-encoded HBx and SATB1 may play an important role in promoting anoikis resistance and metastasis in HBV-associated liver cancer.

A COEUR cohort study of SATB2 expression and its prognostic value in ovarian endometrioid carcinoma.

The aim of this study was to describe the expression of special AT-rich sequence-binding protein 2 (SATB2) in ovarian endometrioid carcinoma (EC). SATB2 is a nuclear matrix-associated transcription factor that is associated with abnormal expression in certain cancers but has not been reported for ovarian carcinoma. SATB2 mRNA and protein expression was first assessed in a pilot cohort of 26 samples by Affymetrix microarray and by routine immunohistochemistry on a small tissue microarray. A large multicenter validation cohort representing the well-characterized cases of 235 ovarian EC from the Canadian Ovarian Experimental Unified Resource (COEUR) was then used to validate this result and to assess the prognostic impact of SATB2 expression. SATB2 staining was scored as negative, weak, moderate, and strong intensity, and by percentage of stained cells. No SATB2 expression was observed in clear cell carcinomas but 10% (n = 3) of the ECs in the pilot cohort showed SATB2 expression. In the validation cohort, strong expression was observed in 11% of ECs, while weak or moderate expression levels were detected in 12% of cases. Evaluation of SATB2 expression with clinicopathological parameters revealed an association with patient age and Federation International of Gynecology and Obstetrics grade but not with disease stage or postoperative residual disease. Any expression of SATB2, independent of intensity, was also associated with longer survival and improved progression-free survival with hazard ratio (HR) = 0.14 (95% CI 0.03-0.56) and HR = 0.16 (95% CI 0.02-1.24) respectively. A greater beneficial effect was observed in patients with stage III/IV disease compared to patients with stage I/II disease. Furthermore, direct comparison of SATB2 with other reported prognostic biomarkers such as progesterone receptor, CDX2 and ß-catenin within this cohort showed that SATB2 had the strongest association with survival. Given the current lack of accurate prognostic factors for these patients, SATB2 has promising clinical utility and warrants further study.

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.

Colitis-associated colorectal adenocarcinomas are frequently associated with non-intestinal mucin profiles and loss of SATB2 expression.

The special AT-rich sequence binding protein 2 (SATB2) is a sensitive and specific diagnostic marker for colorectal adenocarcinoma and reduced expression of SATB2 is associated with a poor prognosis. Colitis-associated colorectal adenocarcinoma often shows distinct morphologic and molecular phenotypes compared to sporadic cases. However, the SATB2 expression profile in colitis-associated carcinoma has not been defined. We performed immunohistochemistry for SATB2 as well as CDX2, MUC5AC, MUC6 and mismatch repair proteins on 60 consecutive colitis-associated carcinomas from 58 inflammatory bowel disease patients and compared the expression profile to a control group of 32 sporadic colorectal carcinomas. Only 26 (43%) colitis-associated carcinomas expressed SATB2, compared to 29 (91%) sporadic colorectal carcinomas (p < 0.0001). MUC5AC expression was more frequently observed in colitis-associated carcinomas than sporadic colorectal caracinomas (52% and 25% respectively; p = 0.013). Eight (13%) cases of colitis-associated carcinoma showed loss of CDX2 expression, which was retained in all of the sporadic controls (p = 0.047). In colitis-associated carcinoma, 50% of SATB2 negative cases had lymph node metastasis compared to only 15% of SATB2 positive cases (p = 0.007). Loss of SATB2 was particularly frequent in mucinous-type tumors, occurring in 83% of these cases. There was no significant association between SATB2 expression and mismatch repair protein status. These data show that the immunoprofile of colitis-associated carcinoma is different than that seen in sporadic cases. In particular, SATB2 is significantly less sensitive in colitis-associated carcinoma and it should be interpreted cautiously as a marker of colorectal origin in colitis patients. The association between loss of SATB2 and lymph node metastasis suggests that it may have similar prognostic value in the setting of inflammatory bowel disease as in sporadic cases.

SATB2 and Hep Par 1 Immunohistochemistry Is Helpful in Distinguishing Between Inflamed and Architecturally Altered Ileal Pouch and Rectal Cuff Mucosa.

The management of patients with ulcerative colitis after proctocolectomy with ileal pouch-anal anastomosis includes independent histological assessments of inflammation in the ileal pouch and the rectal cuff. However, the distinction between pouchitis and cuffitis can be impeded both endoscopically and histologically by the combined effects of inflammation and regeneration. We investigated the use of 2 markers, hepatocyte paraffin 1 (Hep) and SATB2 (special AT-rich sequence-binding protein 2), which are expressed immunohistochemically in the small and large bowel epithelium, respectively, as ancillary methods to deal with this problem. Immunohistochemical staining was performed retrospectively on 20 consecutive pairs of post-ileal pouch-anal anastomosis biopsies with varying degrees of histological inflammation and architectural distortion, which had each been designated as "ileal pouch" or "rectal cuff" by the referring endoscopists. Expression was graded as focal (10% to 74% stained cells) or diffuse (75% to 100%). Among the ileal pouch biopsies, 20 (100%) expressed Hep either diffusely (75%) or focally (25%), whereas SATB2 staining was either negative in 15 (75%) or focal in 5 (25%), the latter group all expressing Hep diffusely. Among the rectal cuff biopsies, 14 expressed SATB2 diffusely. Of these, Hep was either negative in 11 (79%) or focally positive in 3 (21%), the latter group all expressing SATB2 diffusely. Six ostensibly rectal cuff biopsies (30%) expressed Hep diffusely and were negative for SATB2, suggesting endoscopic misidentification. None of the 40 biopsies expressed both markers diffusely. We conclude that in doubtful cases, diffuse expression of either Hep or SATB2 can be helpful in discriminating between ileal pouch and rectal cuff mucosa, respectively.

miR-383 negatively regulates osteoblastic differentiation of bone marrow mesenchymal stem cells in rats by targeting Satb2.

Emerging evidence indicates that microRNAs (miRNAs, miRs) play diverse roles in the regulation of biological processes, including osteoblastic differentiation. In this study, we found that miR-383 is a critical regulator of osteoblastic differentiation. We showed that miR-383 was downregulated during osteoblastic differentiation of rat bone marrow mesenchymal stem cells (BMSCs). Overexpression of miR-383 suppressed osteoblastic differentiation of BMSCs by downregulating alkaline phosphatase (ALP), matrix mineralization, and mRNA and protein levels of RUNX2 and OCN, whereas a knockdown of miR-383 promoted osteoblastic differentiation in vitro. The results of in vivo analysis indicated that inhibition of miR-383 expression enhanced the efficacy of new bone formation in a rat calvarial defect model. Mechanistic experiments revealed that special AT-rich-sequence-binding protein 2 (Satb2) was a direct and functional target of miR-383. Knockdown of Satb2 had inhibitory effects resembling those of miR-383 on the osteoblast differentiation of rat BMSCs. In addition, the positive effect of miR-383 suppression on osteoblastic differentiation was apparently abrogated by Satb2 silencing. Collectively, these results indicate that miR-383 plays an inhibitory role in osteogenic differentiation of rat BMSCs and may act by targeting Satb2.

Special AT-rich sequence binding protein 1 is required for maintenance of T cell receptor responsiveness and development of experimental autoimmune encephalomyelitis.

The genome organizer special AT-rich sequence binding protein 1 (SATB1) regulates specific functions through chromatin remodeling in T helper cells. It was recently reported by our team that T cells from SATB1 conditional knockout (SATB1cKO) mice, in which the Satb1 gene is deleted from hematopoietic cells, impair phosphorylation of signaling molecules in response to T cell receptor (TCR) crosslinking. However, in vivo T cell responses upon antigen presentation in the absence of SATB1 remain unclear. In the current study, it was shown that SATB1 modulates T cell antigen responses during the induction and effector phases. Expression of SATB1 was upregulated in response to TCR stimulation, suggesting that SATB1 is important for this antigen response. The role of SATB1 in TCR responses and induced experimental autoimmune encephalomyelitis (EAE) was therefore examined using the myelin oligodendrocyte glycoprotein peptide 35-55 (MOG35-55) and pertussis toxin. SATB1cKO mice were found to be resistant to EAE and had defects in IL-17- and IFN-γ-producing pathogenic T cells. Thus, SATB1 expression appears necessary for T cell function in the induction phase. To examine SATB1 function during the effector phase, a tamoxifen-inducible SATB1 deletion system, SATB1cKO-ER-Cre mice, was used. Encephalitogenic T cells from MOG35-55-immunized SATB1cKO-ER-Cre mice were transferred into healthy mice. Mice that received tamoxifen before the onset of paralysis were resistant to EAE. Furthermore, no disease progression occurred in recipient mice treated with tamoxifen after the onset of EAE. Thus, SATB1 is essential for maintaining TCR responsiveness during the induction and effector phases and may provide a novel therapeutic target for T cell-mediated autoimmune diseases.

Decreased Expression of SATB2 Associates with Tumor Growth and Predicts Worse Outcome in Patients with Clear Cell Renal Cell Carcinoma.

BACKGROUND/AIM: SATB2 (special AT-rich sequence-binding protein 2) is a DNA-binding protein that is involved in transcriptional regulation and chromatin remodeling. SATB2 protein has been described as a promising novel marker in several human cancers. PATIENTS AND METHODS: This study compared SATB2 expression in tumor and matched unchanged renal tissues collected from 57 patients with clear cell renal cell carcinoma (ccRCC). SATB2 mRNA levels were determined by quantitative polymerase chain reaction, while SATB2 protein expression was estimated by immunohistochemistry. Moreover, the associations between SATB2 expression in ccRCC samples and clinicopathological and survival data of the patients were investigated. RESULTS: The mRNA level of SATB2 was lower in tumor tissues than in samples of corresponding unchanged kidney. Although the average immunoreactivity of SATB2 protein did not differ significantly between cancer cells and epithelial cells of proximal convoluted tubules, the decreased SATB2 expression in tumor specimens inversely correlated with the size of primary tumor and predicted worse patients' outcome. CONCLUSION: The results of the presented study suggest the tumor-suppressing function of SATB2 and that the expression level of this protein can be considered a potential prognostic factor in ccRCC.

Role of conventional immunomarkers, HNF4-α and SATB2, in the differential diagnosis of pulmonary and colorectal adenocarcinomas.

AIMS: Pulmonary (ADC) and colorectal (CRC) adenocarcinomas are frequent entities in pathological routine diagnostics. Whereas the differential diagnosis is usually straightforward based on histomorphology, it can be challenging in small biopsies. In general, CDX-2, CK20, Napsin-A and TTF-1 are recommended immunohistological markers in this scenario. Hepatocyte nuclear factor 4 alpha (HNF4-α) and special AT-rich sequence-binding protein 2 (SATB2) were described recently as promising additional markers, but comprehensive large-scale data are lacking so far. Therefore, we analysed the expression of these six markers in 1021 non-small-cell lung cancers (NSCLC), including 472 ADC as well as in 80 pulmonary metastases of CRC. METHODS AND RESULTS: Tissue microarrays of NSCLC and pulmonary metastases of CRC were stained for CDX-2, CK20, HNF4-α, Napsin-A, SATB2 and TTF-1 and staining results were correlated with clinicopathological variables. ADC exhibited expression of CDX-2, CK20, HNF4-α, Napsin-A, SATB2 and TTF-1 in nine (2%), 21 (4%), 17 (4%), 345 (73%), 35 (7%) and 408 (86%) samples, while 80 CRC were positive in 79 (99%), 74 (93%), 77 (96%), no (0%), 78 (98%) and five (6%) cases, respectively. CONCLUSIONS: In addition to conventional immunomarkers, HNF4-α and particularly SATB2 may be helpful in the differential diagnosis of pulmonary ADC and metastases of CRC.

The crosstalk between p38 and Akt signaling pathways orchestrates EMT by regulating SATB2 expression in NSCLC cells.

Epithelial-mesenchymal transition is a crucial event for metastasis and could be mediated by several pathways such as phosphoinositide 3-kinase/Akt, mitogen-activated protein kinases, as well as many epigenetic regulators. Special AT-rich sequence-binding protein 2 is an epigenetic regulator involved in epithelial-mesenchymal transition and osteoblastic differentiation. It has been reported that the crosstalk between several pathways is responsible for the regulation of epithelial-mesenchymal transition in cancer cells. However, crosstalks between p38 and Akt pathways involved in epithelial-mesenchymal transition are still unknown. We recently reported that there is a crosstalk between p38 and Akt pathways in non-small-cell lung carcinoma cells, and this crosstalk is associated with E-cadherin and special AT-rich sequence-binding protein 2 expressions. Therefore, we aimed to determine whether this crosstalk has a mediator role in the regulation of epithelial-mesenchymal transition in non-small-cell lung carcinoma. Our results showed that inhibition of p38 leads to the disruption of this crosstalk via decreased expression of phosphatase and tensin homolog (PTEN) and subsequently increased activation of Akt in non-small-cell lung carcinoma cells. Then, we found that p38 inhibition upregulated special AT-rich sequence-binding protein 2 expression and reversed epithelial-mesenchymal transition in non-small-cell lung carcinoma cells. Furthermore, special AT-rich sequence-binding protein 2 knockdown abolished the effect of p38 inhibition on epithelial-mesenchymal transition in non-small-cell lung carcinoma cells. In conclusion, our results strongly indicate that the crosstalk between p38 and Akt pathways can determine special AT-rich sequence-binding protein 2 expression and epithelial character of non-small-cell lung carcinoma cells, and special AT-rich sequence-binding protein 2 is a critical epigenetic regulator for epithelial-mesenchymal transition mediated by p38 pathway in non-small-cell lung carcinoma. Our findings will contribute to illuminate the molecular mechanisms of the epithelial-mesenchymal transition process that has a critical significance for lung cancer metastasis.