SATB1 Expression Research Articles

Long Non-Coding RNA ANRIL Regulates Inflammatory Factor Expression in Ulcerative Colitis Via the miR-191-5p/SATB1 Axis.

Ulcerative colitis, an inflammatory bowel disease, manifests with symptoms such as abdominal pain, diarrhea, and mucopurulent feces. The long non-coding RNA (lncRNA) ANRIL exhibits significantly reduced expression in UC, yet its specific mechanism is unknown. This study revealed that ANRIL is involved in the progression of UC by inhibiting IL-6 and TNF-α via miR-191-5P/SATB1 axis. We found that in patients with UC, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were significantly overexpressed in inflamed colon sites, whereas ANRIL was significantly under-expressed and associated with disease severity. The downregulation of ANRIL resulted in the increased expression of IL-6 and TNF-α in LPS-treated FHCs. ANRIL directly targeted miR-191-5p, thereby inhibiting its expression and augmenting SATB1 expression. Moreover, overexpression of miR-191-5p abolished ANRIL-mediated inhibition of IL-6 and TNF-α production. Dual luciferase reporter assays revealed the specific binding of miR-191-5p to ANRIL and SATB1. Furthermore, the downregulation of ANRIL promoted DSS-induced colitis in mice. Together, we provide evidence that ANRIL plays a critical role in regulating IL-6 and TNF-α expression in UC by modulating the miR-191-5p/SATB1 axis. Our study provides novel insights into progression and molecular therapeutic strategies in UC.

Retracted: Study on the Mechanism of miR-34a Affecting the Proliferation, Migration, and Invasion of Human Keloid Fibroblasts by Regulating the Expression of SATB1.

[This retracts the article DOI: 10.1155/2021/8741512.].

A Case of Medullary Carcinoma of the Jejunum Combined with the Intestinal Lymphangiectasia Accompanied by the Malabsorption Syndrome

Aim: to present a clinical and morphological observation of an extremely rare combination of medullary carcinoma of the jejunum and intestinal lymphangiectasia in a 33-year-old patient with clinical features of malabsorption syndrome over the 10 years.Key points. An autopsy revealed a tumor formation spreading from the wall of the jejunum to the mesentery, with metastases to the mesenteric lymph nodes. The medullary carcinoma with positive expression of СD117, DOG1, EMA, PanCK, PDL-1, vimentin, mosaic non-intense expression of CA19-9, calretinin, CD10, CDX2, CEA, MUC-5AC, SATB2, and negative reaction to ALK, CD3, CD8, CD20, CD30, CD31, CD34, CD45, CD56, chromogranin, CK7, CK20, desmin. The proliferative index was high: Ki-67 > 80 %. Moreover, during the histological examination of the intestinal wall, intestinal lymphangiectasia complicated by the malabsorption syndrome was revealed.Conclusion. The uniqueness of this clinical and morphological case is in the combination of medullary carcinoma of the jejunum metastasized to the mesenteric lymph nodes with the underlying intestinal lymphangiectasia accompanied by the development of malabsorption syndrome.

Anti-cancer targets and molecular mechanisms of formononetin in treating osteosarcoma based on network pharmacology.

Osteosarcoma (OS) is a multifactorial bone malignancy that accounts for most cancers in children and adolescents. Formononetin has been proven to exhibit various pharmacological effects including anti-tumor, anti-obesity, anti-inflammation, and neuroprotective effects. Few studies have examined the pharmacological activities of formononetin in OS treatment, but the mechanism has not yet been completely elucidated. Network pharmacology is a new method based on the theory of system biology for analyzing the network of biological systems and selecting specific signal nodes for multi-target drug molecular design. Here, we used network pharmacology to explore the possible mechanism of formononetin in OS treatment. Human OS cell line MG63 was processed with four concentrations (0, 2, 5, 8 μg/mL) of formononetin. Subsequently, an MTT assay was performed to test cell proliferation and a scratch test was used to evaluate the migration ability of cancer cells. Caspase-3, p53, p21, and bcl-2 expression levels incubated with different concentrations of formononetin in MG63 cells were determined using Western blotting. After treated with formononetin for 48 h, MG63 cells exhibited marked apoptosis. The results revealed that certain concentrations of formononetin significantly exerted inhibitory effects on MG63 cell proliferation. Furthermore, formononetin decreased the bcl-2 level in MG63 cells but increased caspase-3, p21, and p53 levels in a concentration-dependent manner. Additionally, formononetin suppressed the expression of SATB2. Therefore, formononetin could dose-dependently inhibit MG63 cell proliferation and induce apparent cell apoptosis, providing a candidate treatment for OS, whereas SATB2 could be a potential prognostic biomarker for screening OS and therapeutic target of formononetin.

Histomorphometric Analysis of 38 Giant Cell Tumors of Bone after Recurrence as Compared to Changes Following Denosumab Treatment.

Giant cell tumor of bone (GCTB) is an osteolytic tumor driven by an H3F3A-mutated mononuclear cell with the accumulation of osteoclastic giant cells. We analyzed tissue from 13 patients with recurrence and 25 patients with denosumab therapy, including two cases of malignant transformation. We found a decrease in the total number of cells (p = 0.03), but not in the individual cell populations when comparing primary and recurrence. The patients treated with denosumab showed induction of osteoid formation increasing during therapy. The total number of cells was reduced (p < 0.0001) and the number of H3F3A-mutated tumor cells decreased (p = 0.0001), while the H3F3A wild-type population remained stable. The KI-67 proliferation rate dropped from 10% to 1% and Runx2- and SATB2-positive cells were reduced. The two cases of malignant transformation revealed a loss of the H3F3A-mutated cells, while the KI-67 rate increased. Changes in RUNX2 and SATB2 expression were higher in one sarcoma, while in the other RUNX2 was decreased and SATB2-positive cells were completely lost. We conclude that denosumab has a strong impact on the morphology of GCTB. KI-67, RUNX2 and SATB2 expression differed depending on the benign or malignant course of the tumor under denosumab therapy.

Loss of SATB2 and CDX2 expression is associated with DNA mismatch repair protein deficiency and BRAF mutation in colorectal cancer.

The relationship between the expression of the SATB2 and CDX2 proteins and common molecular changes and clinical prognosis in colorectal cancer (CRC) still needs further clarification. We collected 1180 cases of CRC and explored the association between the expression of SATB2 and CDX2 and clinicopathological characteristics, molecular alterations, and overall survival of CRC using whole-slide immunohistochemistry. Our results showed that negative expression of SATB2 and CDX2 was more common in MMR-protein-deficient CRC than in MMR-protein-proficient CRC (15.8% vs. 6.0%, P = 0.001; 14.5% vs. 4.0%, P = 0.000, respectively). Negative expression of SATB2 and CDX2 was more common in BRAF-mutant CRC than in BRAF wild-type CRC (17.2% vs. 6.1%, P = 0.003; 13.8% vs. 4. 2%; P = 0.004, respectively). There was no relationship between SATB2 and/or CDX2 negative expression and KRAS, NRAS, and PIK3CA mutations. The lack of expression of SATB2 and CDX2 was associated with poor histopathological features of CRC. In multivariate analysis, negative expression of SATB2 (P = 0.030), negative expression of CDX2 (P = 0.043) and late clinical stage (P = 0.000) were associated with decreased overall survival of CRC. In conclusion, the lack of SATB2 and CDX2 expression in CRC was associated with MMR protein deficiency and BRAF mutation, but not with KRAS, NRAS and PIK3CA mutation. SATB2 and CDX2 are prognostic biomarkers in patients with CRC.

LncRNA SATB2-AS1 promotes tumor growth and metastasis and affects the tumor immune microenvironment in osteosarcoma by regulating SATB2

Our previous report has identified a lncRNA SATB2-AS1, which was significantly up-regulated in osteosarcoma tissue and promotes the proliferation of osteosarcoma cells in vitro. However, the mechanisms of SATB2-AS1 regulating the growth and metastasis of osteosarcoma cells in vivo and its role in the prognosis of osteosarcoma patients are still unclear. In this study, the transcriptome sequencing data of 87 patients with osteosarcoma from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database and 7 patients from our clinical center (GZFPH) was used to evaluate the importance of SATB2-AS1 and SATB2 on the prognosis. The effect of SATB2-AS1 on the growth and metastasis of osteosarcoma cells in vivo was verified by a mouse tumor model. The potential mechanisms of SATB2-AS1 regulating SATB2 were further explored by dual-luciferase reporter gene assay, RNA pull-down assay, and bioinformatics analysis. The results suggested that increased co-expression of SATB2-AS1 and SATB2 was significantly associated with poor overall survival (OS) and relapse-free survival (RFS), and was a biomarker for risk stratification in patients with osteosarcoma. Mechanistically, SATB2-AS1 promotes tumor growth and lung metastasis by regulating SATB2 in vivo. SATB2-AS1 directly binds to POU3F1 for mediating SATB2 expression in MNNG/HOS cells. In addition, SATB2-AS1 and SATB2 might be potential immunomodulators for negatively affecting immune cell infiltration by the IL-17 signaling pathway. In summary, SATB2-AS1 promoted tumor cell growth and lung metastasis by activating SATB2, thereby associated with poor prognosis in patients with osteosarcoma, which indicated that SATB2-AS1 and SATB2 might be novel biomarkers for risk stratification and promising therapeutic targets for osteosarcoma.

Diagnostic gastrointestinal markers in primary lung cancer and pulmonary metastases

Histopathological diagnosis of pulmonary tumors is essential for treatment decisions. The distinction between primary lung adenocarcinoma and pulmonary metastasis from the gastrointestinal (GI) tract may be difficult. Therefore, we compared the diagnostic value of several immunohistochemical markers in pulmonary tumors. Tissue microarrays from 629 resected primary lung cancers and 422 resected pulmonary epithelial metastases from various sites (whereof 275 colorectal cancer) were investigated for the immunohistochemical expression of CDH17, GPA33, MUC2, MUC6, SATB2, and SMAD4, for comparison with CDX2, CK20, CK7, and TTF-1. The most sensitive markers for GI origin were GPA33 (positive in 98%, 60%, and 100% of pulmonary metastases from colorectal cancer, pancreatic cancer, and other GI adenocarcinomas, respectively), CDX2 (99/40/100%), and CDH17 (99/0/100%). In comparison, SATB2 and CK20 showed higher specificity, with expression in 5% and 10% of mucinous primary lung adenocarcinomas and both in 0% of TTF-1-negative non-mucinous primary lung adenocarcinomas (25–50% and 5–16%, respectively, for GPA33/CDX2/CDH17). MUC2 was negative in all primary lung cancers, but positive only in less than half of pulmonary metastases from mucinous adenocarcinomas from other organs. Combining six GI markers did not perfectly separate primary lung cancers from pulmonary metastases including subgroups such as mucinous adenocarcinomas or CK7-positive GI tract metastases. This comprehensive comparison suggests that CDH17, GPA33, and SATB2 may be used as equivalent alternatives to CDX2 and CK20. However, no single or combination of markers can categorically distinguish primary lung cancers from metastatic GI tract cancer.

Identification of New Prognostic Genes and Construction of a Prognostic Model for Lung Adenocarcinoma.

Lung adenocarcinoma (LUAD) is a rapidly progressive malignancy, and its mortality rate is very high. In this study, we aimed at finding novel prognosis-related genes and constructing a credible prognostic model to improve the prediction for LUAD patients. Differential gene expression, mutant subtype, and univariate Cox regression analyses were conducted with the dataset from the Cancer Genome Atlas (TCGA) database to screen for prognostic features. These features were employed in the following multivariate Cox regression analysis and the produced prognostic model included the stage and expression of SMCO2, SATB2, HAVCR1, GRIA1, and GALNT4, as well as mutation subtypes of TP53. The exactness of the model was confirmed by an overall survival (OS) analysis and disease-free survival (DFS) analysis, which indicated that patients in the high-risk group had a poorer prognosis compared to those in the low-risk group. The area under the receiver operating characteristic curve (AUC) was 0.793 in the training group and 0.779 in the testing group. The AUC of tumor recurrence was 0.778 in the training group and 0.815 in the testing group. In addition, the number of deceased patients increased as the risk scores raised. Furthermore, the knockdown of prognostic gene HAVCR1 suppressed the proliferation of A549 cells, which supports our prognostic model that the high expression of HAVCR1 predicts poor prognosis. Our work created a reliable prognostic risk score model for LUAD and provided potential prognostic biomarkers.

Reactivation of corticogenesis-related transcriptional factors BCL11B and SATB2 after ischemic lesion of the adult mouse brain

The aim of this study was to characterize expression of corticogenesis-related transcription factors BCL11B and SATB2 after brain ischemic lesion in the adult mice, and to analyze their correlation to the subsequent brain recovery. Ischemic brain lesion was induced by transient middle cerebral artery occlusion followed by reperfusion, and the animals with ischemic lesion were compared to the sham controls. Progression of the brain damage and subsequent recovery was longitudinally monitored structurally, by magnetic resonance imaging, and functionally, by neurological deficit assessment. Seven days after the ischemic injury the brains were isolated and analyzed by immunohistochemistry. The results showed higher expression in the brain of both, BCL11B and SATB2 in the animals with ischemic lesion compared to the sham controls. The co-expression of both markers, BCL11B and SATB2, increased in the ischemic brains, as well as the co-expression of BCL11B with the beneficial transcriptional factor ATF3 but not its co-expression with detrimental HDAC2. BCL11B was mainly implicated in the ipsilateral and SATB2 in the contralateral brain hemisphere, and their level in these regions correlated with the functional recovery rate. The results indicate that the reactivation of corticogenesis-related transcription factors BCL11B and SATB2 is beneficial after brain ischemic lesion.

Identification of a novel enhancer essential for Satb1 expression in TH2 cells and activated ILC2s.

The genome organizer, special AT-rich binding protein-1 (SATB1), functions to globally regulate gene networks during primary T cell development and plays a pivotal role in lineage specification in CD4+ helper-, CD8+ cytotoxic-, and FOXP3+ regulatory-T cell subsets. However, it remains unclear how Satb1 gene expression is controlled, particularly in effector T cell function. Here, by using a novel reporter mouse strain expressing SATB1-Venus and genome editing, we have identified a cis-regulatory enhancer, essential for maintaining Satb1 expression specifically in TH2 cells. This enhancer is occupied by STAT6 and interacts with Satb1 promoters through chromatin looping in TH2 cells. Reduction of Satb1 expression, by the lack of this enhancer, resulted in elevated IL-5 expression in TH2 cells. In addition, we found that Satb1 is induced in activated group 2 innate lymphoid cells (ILC2s) through this enhancer. Collectively, these results provide novel insights into how Satb1 expression is regulated in TH2 cells and ILC2s during type 2 immune responses.

SATB1 is a master gatekeeper that limits virus-specific CD8 +T cell differentiation.

Abstract Special AT-rich sequence binding protein-1 (SATB1) is a chromatin binding protein that has key roles in ensuring appropriate chromatin structure and remodelling during T cell development. While a role for SATB1 in both CD4 +T regulatory and CD4 +T H2 lineage specific function has been described, little is known about its role during virus-specific CD8 +T cell differentiation. Here we demonstrate that SATB1 down regulation is associated with naïve CD8 +T cell activation and subsequent differentiation. Genome wide SATB1 binding indicates that SATB1 is critical for maintaining the naïve CD8 +T cell transcriptional programs prior to activation. Overexpression of SATB1 upon CD8 +T cell activation results in major restraint of virus-specific CD8 +cell differentiation resulting in lower expression of inflammatory chemokine receptors, checkpoint molecules such as PD-1 and limits effector CD8 +T cell infiltration into infected tissues. Moreover, SATB1 over expression maintains high levels of TCF-1 expression and maintenance of the naïve T cell program. Our data suggest that SATB1 expression within naïve CD8 +T cells acts as gatekeeper for maintaining the naïve T cell program, and that down regulation upon activation is required for optimal effector CD8 +T cell differentiation. Supported by grants from the Australian Research Council (DP170102020).

Abstract 3637: Extracellular matrix drives high-grade breast cancer immune suppression down-modulating PD-1 on Treg cells via the IL-23/SATB1 axis

Abstract The pathological grade defines tumor aggressiveness and, indeed, high-grade breast cancer (HGBC), regardless of molecular findings, is characterized by a very aggressive clinical course and a poor prognosis in spite of the availability of chemotherapy regimens and specific-targeted agents. Both the cellular and the extracellular compartments of the tumor microenvironment (TME) can contribute to the evolution of BC by immune escape and immune suppression processes. In this context, structural and extracellular components of the TME, namely the extracellular matrix (ECM), has been shown to contribute to many aspects of tumor progression, exerting important regulatory functions on tumor cells. The relevance of the ECM in cancer progression is strengthened by study showing that the ECM composition is a prognostic factor able to identify patients subgroups endowed with a different clinical outcome according to the distinct enrichment in ECM genes leading to four specific ECM signatures (ECM 1-4). Among the different ECM-related signatures, only the ECM3 signature - characterizing about 35 % of HGBC - identifies the most aggressive tumors with epithelial mesenchymal transition (EMT) features, poor prognosis, T-cell exclusion and an increased infiltration of myeloid-derived suppressor cells (MDSCs). To evaluate whether local immune suppressive features of ECM3+ tumors can be intercepted in the peripheral blood (PB), to represent a potential biomarker for this subset of tumors, we collected consecutive HGBC patients that included 22 ECM3+ and 30 ECM3- and performed a multiparametric flow cytometry analysis. We found PD-1neg Treg being correlated to ECM3 patients and through ad hoc mouse BC models, we provided the mechanisms through which SPARC, a key functional gene of the ECM3 signature, was responsible for the down-modulation of PD-1 on Treg, positively affecting their suppressive activity. By sustaining the release of IL-23, SPARC promotes SATB1 expression that repress PD-1. Notably, fluvastatin treatment in vivo decreased the expression of SATB1 in treated Treg cells, a result paralleled by an increased expression of PD-1 on Treg cells. Our data extend the regulatory activity of the extracellular matrix and SPARC, which are large characterized for myeloid cells, to regulatory T-cells also offering new possible targets for the treatment of high-grade breast tumors. Citation Format: Giovanna Talarico, Mara Lecchi, Massimo Costanza, Claudia Chiodoni, Vera Cappelletti, Paolo Verderio, Massimo Di Nicola, Francesco Bertolini, Mario Paolo Colombo, Sabina Sangaletti. Extracellular matrix drives high-grade breast cancer immune suppression down-modulating PD-1 on Treg cells via the IL-23/SATB1 axis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3637.

Expression of SATB1 and SATB2 in the brain of bony fishes: what fish reveal about evolution

Satb1 and Satb2 belong to a family of homeodomain proteins with highly conserved functional and regulatory mechanisms and posttranslational modifications in evolution. However, although their distribution in the mouse brain has been analyzed, few data exist in other non-mammalian vertebrates. In the present study, we have analyzed in detail the sequence of SATB1 and SATB2 proteins and the immunolocalization of both, in combination with additional neuronal markers of highly conserved populations, in the brain of adult specimens of different bony fish models at key evolutionary points of vertebrate diversification, in particular including representative species of sarcopterygian and actinopterygian fishes. We observed a striking absence of both proteins in the pallial region of actinopterygians, only detected in lungfish, the only sarcopterygian fish. In the subpallium, including the amygdaloid complex, or comparable structures, we identified that the detected expressions of SATB1 and SATB2 have similar topologies in the studied models. In the caudal telencephalon, all models showed significant expression of SATB1 and SATB2 in the preoptic area, including the acroterminal domain of this region, where the cells were also dopaminergic. In the alar hypothalamus, all models showed SATB2 but not SATB1 in the subparaventricular area, whereas in the basal hypothalamus the cladistian species and the lungfish presented a SATB1 immunoreactive population in the tuberal hypothalamus, also labeled with SATB2 in the latter and colocalizing with the gen Orthopedia. In the diencephalon, all models, except the teleost fish, showed SATB1 in the prethalamus, thalamus and pretectum, whereas only lungfish showed also SATB2 in prethalamus and thalamus. At the midbrain level of actinopterygian fish, the optic tectum, the torus semicircularis and the tegmentum harbored populations of SATB1 cells, whereas lungfish housed SATB2 only in the torus and tegmentum. Similarly, the SATB1 expression in the rhombencephalic central gray and reticular formation was a common feature. The presence of SATB1 in the solitary tract nucleus is a peculiar feature only observed in non-teleost actinopterygian fishes. At these levels, none of the detected populations were catecholaminergic or serotonergic. In conclusion, the protein sequence analysis revealed a high degree of conservation of both proteins, especially in the functional domains, whereas the neuroanatomical pattern of SATB1 and SATB2 revealed significant differences between sarcopterygians and actinopterygians, and these divergences may be related to the different functional involvement of both in the acquisition of various neural phenotypes.

P754 Beyond Paneth cell metaplasia: Small intestinal metaplasia of the sigmoid colon in patients with Inflammatory Bowel Disease

Abstract Background Paneth cells are normally found in the small intestine, and when found in the left colon, they represent Paneth cell metaplasia (PCM). This finding indicates a chronic inflammatory state and is seen in some patients with inflammatory bowel disease (IBD). However, small intestinal differentiation beyond PCM has not been reported. We report a broader range of small intestinal metaplasia in the sigmoid colon in patients with IBD, including loss of expression of the colonic marker SATB2, presence of a brush border and villous architecture, and gain of expression of the small intestinal markers CD10 and HepPar1. We perform a pilot study to investigate the frequency, staining patterns, and clinical correlates of this metaplastic phenomenon. Methods A database search for sigmoid biopsies for the words “Paneth cell metaplasia” from 2010-2018 returned 862 cases. The 100 most recent consecutive cases with a history of IBD were reviewed and confirmed to have PCM in non-neoplastic sigmoid biopsies in 96 cases. Of these, 94 blocks from 91 patients (age range 7-88, median age 43, 53% male, 74% ulcerative colitis (UC), 23% Crohn’s disease, 3% IBD) were on file. IHC staining for HepPar1, CD10, and SATB2 was performed on each case. Results Of the 94 cases, 13 (13.8%) had HepPar1 positivity, 5 (5.3%) had CD10 positivity, 2 (2.1%) had SATB2 loss, 1 (1.1%) had reduced SATB2 expression, and 2 showed villous architectural features. Extensive positivity for CD10 was seen in 3 (3.2%) cases, and one case showed all 3 IHC markers of small intestinal metaplasia. Of the CD10+ cases, there were 3 UC, 1 Crohn's, and 1 IBD (Table 1). The index case (sigmoid colon) showed a brush border (Figure 1) and intermixed small (Figure 2, red arrows) and large bowel (Figure 2, black arrows) differentiation. Conclusion A range of small intestinal differentiation may be seen in the left colon in IBD patients, including PCM, the presence of brush border, villous architecture, CD10 and HepPar1 positivity, and reduced or lost SATB2 expression. Since the frequency of HepPar1+&amp;gt;CD10+&amp;gt;SATB2 loss, there may be a sequence of small intestinal metaplasia, with PCM occurring first, and loss of SATB2 reflecting more advanced metaplasia. Previous studies suggest that SATB2 and HepPar1 are helpful in distinguishing between inflamed ileal pouch vs rectal cuff in patients with IBD, and that CD10 could be used to distinguish between ileum and colon in anastomoses, but our data refute these claims. SATB2 loss has been described in dysplastic lesions in patients with IBD, and thus these markers could serve as biomarkers of progression to dysplasia.

SATB2, coordinated with CUX1, regulates IL-1β-induced senescence-like phenotype in endothelial cells by fine-tuning the atherosclerosis-associated p16INK4a expression.

Genome-wide association studies (GWAS) have validated a strong association of atherosclerosis with the CDKN2A/B locus, a locus harboring three tumor suppressor genes: p14ARF , p15INK4b , and p16INK4a . Post-GWAS functional analysis reveals that CUX is a transcriptional activator of p16INK4a via its specific binding to a functional SNP (fSNP) rs1537371 on the atherosclerosis-associated CDKN2A/B locus, regulating endothelial senescence. In this work, we characterize SATB2, another transcription factor that specifically binds to rs1537371. We demonstrate that even though both CUX1 and SATB2 are the homeodomain transcription factors, unlike CUX1, SATB2 is a transcriptional suppressor of p16INK4a and overexpression of SATB2 competes with CUX1 for its binding to rs1537371, which inhibits p16INK4a and p16INK4a -dependent cellular senescence in human endothelial cells (ECs). Surprisingly, we discovered that SATB2 expression is transcriptionally repressed by CUX1. Therefore, upregulation of CUX1 inhibits SATB2 expression, which enhances the binding of CUX1 to rs1537371 and subsequently fine-tunes p16INK4a expression. Remarkably, we also demonstrate that IL-1β, a senescence-associated secretory phenotype (SASP) gene itself and a biomarker for atherosclerosis, induces cellular senescence also by upregulating CUX1 and/or downregulating SATB2 in human ECs. A model is proposed to reconcile our findings showing how both primary and secondary senescence are activated via the atherosclerosis-associated p16INK4a expression.

Expression of SATB2 in primary cutaneous sarcomatoid neoplasms: a potential diagnostic pitfall

SATB2 can be used as an immunohistochemical marker for osteoblastic differentiation. The differential diagnosis of a cutaneous sarcomatoid neoplasm sometimes includes osteosarcoma when the tumour concomitantly involves the skin, soft tissue, and bone, or when there is a past medical history of osteosarcoma. As the utility of SATB2 immunohistochemistry in these scenarios was unclear, we aimed to determine the frequency and the pattern of SATB2 expression in a variety of cutaneous sarcomatoid neoplasms. SATB2 expression by immunohistochemistry was evaluated by intensity (0-3) and extent (0-100%) of staining to generate an h-score for each case. Expression levels were classified into high-positive (h-score ≥100), low-positive (20-99), and negative (<20) groups. Positive SATB2 expression was observed in 18/23 (78%) atypical fibroxanthomas (AFX), 10/19 (53%) pleomorphic dermal sarcomas, 9/20 (45%) cutaneous sarcomatoid squamous cell carcinomas, 14/39 (36%) sarcomatoid melanomas, 2/13 (15%) poorly differentiated cutaneous angiosarcomas, 10/17 (59%) high-grade cutaneous leiomyosarcomas, and 7/8 (88%) osteosarcoma controls. With the exception of AFX, all cutaneous neoplasms showed significantly lower average h-scores than osteosarcoma. AFX gave the highest average h-score (71) and percentage of high-positive cases (48%) among all examined cutaneous neoplasms. Only two (1.5%) of all cutaneous cases showed strong intensity of staining. Common SATB2 expression in various cutaneous sarcomatoid neoplasms poses a potential diagnostic pitfall when the differential diagnosis includes osteosarcoma. Requirement of strong staining and a high-positive h-score improves the specificity of SATB2 in differentiating these tumours from osteosarcoma.

Single-cell transcriptomic analysis reveals diversity within mammalian spinal motor neurons

Spinal motor neurons (MNs) integrate sensory stimuli and brain commands to generate movements. In vertebrates, the molecular identities of the cardinal MN types such as those innervating limb versus trunk muscles are well elucidated. Yet the identities of finer subtypes within these cell populations that innervate individual muscle groups remain enigmatic. Here we investigate heterogeneity in mouse MNs using single-cell transcriptomics. Among limb-innervating MNs, we reveal a diverse neuropeptide code for delineating putative motor pool identities. Additionally, we uncover that axial MNs are subdivided into three molecularly distinct subtypes, defined by mediolaterally-biased Satb2, Nr2f2 or Bcl11b expression patterns with different axon guidance signatures. These three subtypes are present in chicken and human embryos, suggesting a conserved axial MN expression pattern across higher vertebrates. Overall, our study provides a molecular resource of spinal MN types and paves the way towards deciphering how neuronal subtypes evolved to accommodate vertebrate motor behaviors.

Expression of SATB2, RUNX2, and SOX9 and possible osteoblastic and chondroblastic differentiation in chondroblastoma.

Chondroblastoma (CB) is histologically characterized by oval to polygonal-shaped mononuclear neoplastic cells, multinucleated osteoclastic giant cells, and eosinophilic matrix with occasional calcification. Genetically, the majority of CBs harbor H3F3B p.K36M mutation. Despite the historical nomenclature, it has been reported that the matrix of CB is similar to osteoid rather than true cartilage; however, it remains unclear whether neoplastic cells in CB have the potential for osteoblastic differentiation. To clarify this issue, we immunohistochemically examined the expression of osteogenic and chondrogenic markers (SATB2, RUNX2, p63, and SOX9) as well as H3K36M mutant protein in 33 cases of CB. All 33 cases of CB were positive for H3K36M, while SATB2, RUNX2, p63, and SOX9 were expressed in 30/33 (91%), 33/33 (100%), 29/33 (88%), and 31/32 (97%) CB cases, respectively. Our immunohistochemical results suggest that neoplastic cells in CB frequently express both osteogenic and chondrogenic markers and may have an intermediate feature of osteoblastic and chondroblastic nature.

Psammomatoid Ossifying Fibroma Is Defined by SATB2 Rearrangement

Psammomatoid ossifying fibroma (PsOF), also known as juvenile PsOF, is a benign fibro-osseous neoplasm predominantly affecting the extragnathic bones, particularly the frontal and ethmoid bones, with a preference for adolescents and young adults. The clinical and morphologic features of PsOF may overlap with those of other fibro-osseous lesions, and additional molecular markers would help increase diagnostic accuracy. Because identical chromosomal breakpoints at bands Xq26 and 2q33 have been described in 3 cases of PsOF located in the orbita, we aimed to identify the exact genes involved in these chromosomal breakpoints and determine their frequency in PsOF using transcriptome sequencing and fluorescence in situ hybridization (FISH). We performed whole RNA transcriptome sequencing on frozen tissue in 2 PsOF index cases and identified a fusion transcript involving SATB2, located on chromosome 2q33.1, and AL513487.1, located on chromosome Xq26, in one of the cases. The fusion was validated using reverse transcription (RT)-PCR and SATB2 FISH. The fusion lead to a truncated protein product losing most of the functional domains. Subsequently, we analyzed an additional 24 juvenile PsOFs, 8 juvenile trabecular ossifying fibromas (JTOFs), and 11 cemento-ossifying fibromas (COFs) for SATB2 using FISH and found evidence of SATB2 gene rearrangements in 58% (7 of 12) of the evaluable PsOF cases but not in any of the evaluable JTOF (n = 7) and COF (n = 7) cases. A combination of SATB2 immunofluorescence and a 2-color SATB2 FISH in our index case revealed that most tumor cells harboring the rearrangement lacked SATB2 expression. Using immunohistochemistry, 65% of PsOF, 100% of JTOF, and 100% of COF cases showed moderate or strong staining for SATB2. In these cases, we observed a mosaic pattern of expression with >25% of the spindle cells in between the bone matrix, with osteoblasts and osteocytes being positive for SATB2. Interestingly, 35% (8 of 23) of PsOFs, in contrast to JTOFs and COFs, showed SATB2 expression in <5% of cells. To our knowledge, this is the first report that shows the involvement of SATB2 in the development of a neoplastic lesion. In this study, we have showed that SATB2 rearrangement is a recurrent molecular alteration that appears to be highly specific for PsOF. Our findings support that PsOF is not only morphologically and clinically but also genetically distinct from JTOF and COF.