Special AT-rich Sequence Research Articles

CircSATB2 modulates fear extinction memory via Robo3-driven synaptic plasticity.

Circular RNAs (circRNAs) are novel class of stable regulatory RNAs abundantly expressed in the brain. However, their role in fear extinction (EXT) memory remains largely unexplored. To investigate the mechanisms of Circular Special AT-rich Sequence Binding Protein 2 (circSatb2) in EXT memory, we constructed a lentivirus overexpressing circSatb2 and injected it into the infralimbic prefrontal cortex (ILPFC) of the mouse brain. Following extinction training and subsequent testing, we observed an essential role of circSatb2 in this dynamic process. RNA sequencing (RNA-seq) and bioinformatics analyses revealed that circSatb2 enhances the transcription of Roundabout Guidance Receptor 3 (Robo3), a key gene implicated in axon guidance and synaptic plasticity, which was validated by RT-qPCR. Neuronal morphology was assessed using confocal microscopy to determine changes in dendritic spine density. Our results demonstrated that circSatb2 significantly enhances Robo3 transcription, leading to increased dendritic spine formation and improved synaptic plasticity. In conclusion, circSatb2 promotes the formation of EXT memory by upregulating Robo3 transcription and enhancing synaptic plasticity. These findings position circSatb2 as a potential therapeutic target for disorders associated with memory impairment.

Perianal Paget Disease With an Enteric Phenotype and Associated In-Situ/Dysplastic Glandular Component: Report of a Potentially Novel Entity and Review of the Literature.

Extramammary Paget disease is an uncommon cutaneous malignancy that primarily affects areas rich in apocrine glands. Here, we aim to present an 84-year-old woman with a distinctive perianal neoplastic process comprised of conventional Paget disease with an intertwined in-situ glandular component. Rare foci of glands embedded in pools of mucin were also identified in the most recent excision, consistent with mucinous adenocarcinoma. Immunohistochemical staining demonstrated an enteric phenotype of the tumor cells, with expression of keratin 20, caudal type homeobox transcription factor 2 (CDX2), and special AT-rich sequence binding protein 2 (SATB2) (patchy, weak); keratin 7 and BerEP4 staining were also noted. Molecular analysis via next generation sequencing revealed pathogenic variants in ERBB2, TP53, and SF3B1. Given the unique histomorphology and immunohistochemical staining pattern, suspicion for a colorectal primary tumor was high, however; extensive workup including imaging, testing for tumor markers, and colonoscopic evaluation has not identified any other lesion thus far. Multiple biopsies and excisions in the area demonstrated recurrent disease over a 4-year span; with no evidence of deep invasion or metastasis. This tumor appears to be exceptional among reports in the literature given its extensive in-situ glandular component; and we are not aware of any documented SF3B1 mutation to date. Disease recurrence in this patient highlights the need for clinical vigilance. Defining the molecular profile in these lesions can also be useful, particularly when assessing potential treatment options for advanced disease.

Sox6 and ALDH1A1 Truncation by Asparagine Endopeptidase Defines Selective Neuronal Vulnerability in Parkinson's Disease.

Dopaminergic neurons in the substantia nigra pars compacta (SNpc) demonstrate regionally selective susceptibility in Parkinson's disease (PD) compared to those in the ventral tegmental area (VTA). However, the molecular mechanism for this distinct vulnerability remains unclear. Here, it is shown that Legumain, also known as asparagine endopeptidase (AEP), is activated in a subgroup of SRY-box transcription factor 6 /Aldehyde dehydrogenase 1 family member A1, (Sox6+/ALDH1A1+) neurons in the ventral tier of the SNpc and cleaves Sox6 and ALDH1A1, leading to repression of Special AT-rich sequence binding protein 1 (Satb1) that is a dimeric/tetrameric transcription factor specifically binding to AT-rich DNA sequences, and toxic dopamine metabolite accumulation. AEP cuts Sox6 and ALDH1A1 in dopaminergic neurons that project to the locus coeruleus (LC), abolishing Sox6's transcriptive and ALDH1A1's enzymatic activities. Co-expressing AEP-truncated Sox6 and ALDH1A1 fragments in 3-month-old A53T SNCA transgenic mice accelerates dopamine degeneration, whereas expressing AEP-resistant Sox6 N336A/N446A and ALDH1A1 N220A mutants alleviates rotenone-induced PD pathologies. Hence, different circuitries and intrinsic properties of dopaminergic neurons in the SNpc and VTA render differential predispositions in PD.

Utility of special AT-rich sequence-binding protein 2 (SATB2) immunohistochemistry as a marker for secondary perianal paget disease.

A panel-based approach using immunohistochemistry (IHC) is currently used for subtyping perianal Paget disease (PPD) in the absence of a synchronous neoplasm. Special AT-rich Sequence Binding Protein 2 (SATB2) has been established as a sensitive and specific marker for lower gastrointestinal tract carcinomas. We evaluated its performance as a marker of secondary PPD. A panel of IHCs including CK7, CK20, GCDFP-15, CDX2, and SATB2 were performed on fifteen cases of PPD (identified between 1991-2001) and seven cases of primary vulvar Paget disease with perianal involvement. Eight cases (53%) were classified as secondary PPD based on the presence of a synchronous (n = 7) or a metachronous neoplasm (n = 1). There was no differential staining for CK7 (positive in 7/7 primary vs. 7/8 secondary PPD; P = 1.00) and CK20 (positive in 4/7 primary vs. 8/8 secondary PPD; P = .08). GCDFP-15 was positive in 5/7 cases of primary PPD while negative in all cases of secondary PPD (P = .01). CDX2 was positive in all cases of secondary PPD (P = .001) while SATB2 was positive in 7/8 cases of secondary PPD (P = .01). Both CDX2 and SATB2 were positive in 1/7 cases of primary PPD. The addition of an IHC panel in conjunction with clinical/imaging findings can help definitively classify PPD as either primary or secondary in most cases. We show that SATB2 has comparable performance to CDX2 and can be a helpful additional tool.

Oncogenic Role of SATB2 In Vitro: Regulator of Pluripotency, Self-Renewal, and Epithelial-Mesenchymal Transition in Prostate Cancer.

Special AT-rich sequence binding protein-2 (SATB2) is a nuclear matrix protein that binds to nuclear attachment regions and is involved in chromatin remodeling and transcription regulation. In stem cells, it regulates the expression of genes required for maintaining pluripotency and self-renewal and epithelial-mesenchymal transition (EMT). In this study, we examined the oncogenic role of SATB2 in prostate cancer and assessed whether overexpression of SATB2 in human normal prostate epithelial cells (PrECs) induces properties of cancer stem cells (CSCs). The results demonstrate that SATB2 is highly expressed in prostate cancer cell lines and CSCs, but not in PrECs. Overexpression of SATB2 in PrECs induces cellular transformation which was evident by the formation of colonies in soft agar and spheroids in suspension. Overexpression of SATB2 in PrECs also resulted in induction of stem cell markers (CD44 and CD133), pluripotency-maintaining transcription factors (cMYC, OCT4, SOX2, KLF4, and NANOG), CADHERIN switch, and EMT-related transcription factors. Chromatin immunoprecipitation assay demonstrated that SATB2 can directly bind to promoters of BCL-2, BSP, NANOG, MYC, XIAP, KLF4, and HOXA2, suggesting SATB2 is capable of directly regulating pluripotency/self-renewal, cell survival, and proliferation. Since prostate CSCs play a crucial role in cancer initiation, progression, and metastasis, we also examined the effects of SATB2 knockdown on stemness. SATB2 knockdown in prostate CSCs inhibited spheroid formation, cell viability, colony formation, cell motility, migration, and invasion compared to their scrambled control groups. SATB2 knockdown in CSCs also upregulated the expression of E-CADHERIN and inhibited the expression of N-CADHERIN, SNAIL, SLUG, and ZEB1. The expression of SATB2 was significantly higher in prostate adenocarcinoma compared to normal tissues. Overall, our data suggest that SATB2 acts as an oncogenic factor where it is capable of inducing malignant changes in PrECs by inducing CSC characteristics.

Astrocytes of the Anterior Commissure Regulate the Axon Guidance Pathways of Newly Generated Neocortical Neurons in the Opossum Monodelphis domestica.

In marsupials, upper-layer cortical neurons derived from the progenitors of the subventricular zone of the lateral ventricle (SVZ) mature morphologically and send their axons to form interhemispheric connections through the anterior commissure. In contrast, eutherians have evolved a new extra callosal pathway, the corpus callosum, that interconnects both hemispheres. In this study, we aimed to examine neurogenesis during the formation of cortical upper layers, including their morphological maturation in a marsupial species, namely the opossum (Monodelphis domestica). Furthermore, we studied how the axons of upper layers neurons pass through the anterior commissure of the opossum, which connects neocortical areas. We showed that upper-layer II/III neurons were generated within at least seven days in the opossum neocortex. Surprisingly, these neurons expressed special AT-rich sequence binding protein 2 (Satb2) and neuropilin 1 interacting protein (Nrp1), which are proteins known to be essential for the formation of the corpus callosum in eutherians. This indicates that extrinsic, but not intrinsic, cues could be key players in guiding the axons of newly generated cortical neurons in the opossum. Although oligodendrocyte precursor cells were present in the neocortex and anterior commissure, newly generated upper-layer neurons sent unmyelinated axons to the anterior commissure. We also found numerous GFAP-expressing progenitor cells in both brain structures, the neocortex and the anterior commissure. However, at P12-P17 in the opossums, a small population of astrocytes was observed only in the midline area of the anterior commissure. We postulate that in the opossum, midline astrocytes allow neocortical axons to be guided to cross the midline, as this structure resembles the glial wedge required by fibers to cross the midline area of the corpus callosum in the rodent.

Triptolide inhibits esophageal squamous cell carcinoma progression by regulating the circNOX4/miR-153-3p/SATB1 signaling pathway.

To explore the role and mechanism of triptolide in regulating esophageal squamous cell carcinoma (ESCC) progression by mediating the circular RNA (circRNA)-related pathway. The expression levels of circNOX4, miR-153-3p and special AT-rich sequence binding protein-1 (SATB1) were measured by qRT-PCR. Cell proliferation was confirmed by cell counting kit-8 assay and colony formation assay. Flow cytometry was employed to measure cell apoptosis and cell cycle process. Moreover, cell migration and invasion were detected using transwell assay. The protein levels of epithelial-mesenchymal transformation markers and SATB1 were determined by western blot analysis. Furthermore, dual-luciferase reporter assay and RIP assay were performed to confirm the interaction between miR-153-3p and circNOX4 or SATB1. Xenograft tumor models were built to verify the effects of triptolide and circNOX4 on ESCC tumor growth. CircNOX4 was highly expressed in ESCC tissues and cells, and its expression could be reduced by triptolide. Triptolide could inhibit ESCC proliferation, cell cycle process, migration, invasion, EMT process, and promote apoptosis, while these effects were reversed by circNOX4 overexpression. MiR-153-3p could be sponged by circNOX4, and the promotion effect of circNOX4 on the progression of triptolide-treated ESCC cells was abolished by miR-153-3p overexpression. SATB1 was a target of miR-153-3p. Also, SATB1 knockdown reversed the enhancing effect of miR-153-3p inhibitor on the progression of triptolide-treated ESCC cells. Triptolide reduced ESCC tumor growth by regulating the circNOX4/miR-153-3p/SATB1 axis. Triptolide could hinder ESCC progression, which was mainly achieved by regulating the circNOX4/miR-153-3p/SATB1 axis.

Depletion of DNTTIP2 Induces Cell Cycle Arrest in Pancreatic Cancer Cells.

Pancreatic cancer is one of the most lethal malignant cancers worldwide and the seventh most common cause of cancer-related death in both sexes. Herein, we analyzed open access data and discovered that expression of a gene called deoxynucleotidyltransferase terminal-interacting protein 2 (DNTTIP2) is linked to prognosis of pancreatic ductal adenocarcinoma (PDAC). We then elucidated the role of DNTTIP2 in the proliferation of pancreatic cancer cells in vitro. A WST-8 assay, cell cycle analysis, Annexin-V staining, quantitative reverse transcription-PCR, and western blot analysis were conducted to assess cell proliferation, cell cycle, apoptosis, and expression of DNTTIP2 mRNA and protein, respectively, in DNTTIP2-depleteted MIA-PaCa-2 and PK-1 cells. Depletion of DNTTIP2 induced G1 arrest in MIA-PaCa-2 cells by decreasing expression of special AT-rich sequence binding protein 1 (SATB1) and cyclin-dependent kinase 6 (CDK6). In addition, depletion of DNTTIP2 induced G2 arrest in PK-1 cells by decreasing expression of CDK1. Depletion of DNTTIP2 did not induce apoptosis in MIA-PaCa-2 or PK-1 cells. DNTTIP2 is involved in proliferation of pancreatic cancer cells. Thus, DNTTIP2 is a potential target for inhibiting progression of pancreatic cancers.

Correlations of special AT-rich sequence binding protein 2 and chitinase-3-like protein-1 with sensitivity to paclitaxel chemotherapy for gastric cancer

Abstract Background: Our objective was to examine the associations between special AT-rich sequence binding protein 2 (SATB2) and chitinase-3-like protein-1 (CHI3L1) and the responsiveness to paclitaxel treatment in individuals with gastric cancer. Methods: From March 2018 to October 2020, our hospital collected gastric cancer samples along with adjacent gastric mucosal tissues located more than 5 cm away from the cancerous margin. These samples were obtained from 90 patients who underwent chemotherapy regimens containing paclitaxel. To assess the rates of positive expression of CHI3L1 and SATB2 in gastric cancer and adjacent tissues, the immunohistochemical streptavidin-peroxidase (SP) technique was utilized. Results: The positive expression rate of CHI3L1 was higher in gastric cancer tissues compared to adjacent tissues, while the positive expression rate of SATB2 was lower (P<0.05). Risk factors that influenced the positive expression of CHI3L1 in gastric cancer tissues included the level of differentiation, tumor-node-metastasis (TNM) stage, and the presence of lymph node metastasis (OR>1, P<0.05). Additionally, the positive expression of SATB2 was also affected by TNM stage and lymph node metastasis, which were identified as risk factors (OR>1, P<0.05). In gastric cancer tissues, there was a negative correlation observed between the expressions of CHI3L1 and SATB2 (r<0, P<0.05). According to the analysis results of Kendall’s tau-b (K), it was found that the presence of CHI3L1 had an inverse relationship with the responsiveness to paclitaxel-based chemotherapy in gastric cancer (r=-0.498, P=0.000), while SATB2 exhibited a positive correlation with the sensitivity (r=0.513, P=0.000). During the 3-year follow-up after chemotherapy, the survival rate was 55.55% (50/90). Conclusions: The findings indicate a strong correlation between SATB2 and CHI3L1 with the TNM stage, lymph node metastasis, response to paclitaxel-based chemotherapy, and the overall survival rate of individuals.

Microfracture technique combined with mesenchymal stem cells inducer represses miR-708-5p to target special at-rich sequence-binding protein 2 to drive cartilage repair and regeneration in rabbit knee osteoarthritis

Knee osteoarthritis (KOA) is a degenerative joint illness which leads to knee pain and functional limitation. In this study, we combined microfracture surgery with kartogenin (KGN), a small bioactive molecule used to promote the differentiation of mesenchymal stem cells (MSCs), and explored its impact on cartilage repair and possible latent mechanisms of action. The research offers a brand-new idea for the clinical cure of KOA. The microfracture technique in combination with KNG treatment was performed on a rabbit model of KOA. Animal behaviour was evaluated after the intra-articular injection of miR-708-5p and Special AT-rich sequence binding protein 2 (SATB2) lentiviruses. Later, the expression of the tumour necrosis factor α (TNF-α) and interleukin- 1 (IL-1), the pathology of synovial tissue and cartilage tissue, and the positive cartilage type II collagen, MMP-1, MMP-3 and TIMP-1 were detected. Finally, a luciferase assay was conducted to verify the interaction of miR-708-5p and SATB2. Our results showed that miR-708-5p was elevated in the rabbit KOA model; however, the expression of SATB2 was reduced. Meanwhile, the microfracture technology combined with MSCs inducer KGN drove cartilage repair and regeneration in rabbit KOA by repressing the miR-708-5p expression. We also found that miR-708-5p directly targeted the SATB2 mRNA to regulate its expression. Furthermore, our data urged that elevating miR-708-5p or restraining SATB2 may reverse the therapeutic effect of the microfracture technique combined with MSCs inducer on rabbit KOA. Microfracture technique combined with MSCs inducer represses miR-708-5p to target SATB2 to drive cartilage repair and regeneration in rabbit KOA. This indicates that the microfracture technique combined with MSCs inducers is supposed to be an effective latent method for osteoarthritis cure.

Immediate early response 3 gene promotes aggressive progression and autophagy of AML by negatively regulating AKT/mTOR

BackgroundImmediate early response 3 (IER3) plays a vital role in many tumors. This study aims to explore the function and mechanism of IER3 in Acute myeloid leukemia (AML). MethodsThe expression of IER3 in AML was performed by bioinformatics analysis. CCK-8 proliferation assay, flow cytometry cycle assay, clone formation assay, and tumorigenic ability were used to investigate the effect of IER3 on AML cells. Unbiased label-free quantitative proteomics and label-free quantitative phosphoproteomics analysis were performed. The regulatory relationship between SATB1(Special AT-rich sequence binding protein 1) and IER3 was investigated by Real time-PCR, Western blot, Chromatin immunoprecipitation (CHIP), and PCR. ResultsThe result indicated that the prognosis of the high IER3 expression group was significantly worse than that of the low expression group. CCK-8 assay showed that IER3 enhanced the proliferation ability. Cell cycle analysis showed IER3 could promote HL60 cells to enter the S phase of DNA synthesis from the quiescent phase. IER3 could stimulate HEL cells to enter mitosis. Clone-formation experiments suggested that IER3 enhanced clonogenic ability.IER3 promoted the tumorigenesis of AML. Further experimental investigation revealed that IER3 promoted autophagy and induced the occurrence and development of AML by negatively regulating the phosphorylation activation of AKT/mTOR pathway. SATB1 was found to bind to the promoter region of IER3 gene and negatively regulate its transcription. ConclusionIER3 could promote the development of AML and induce autophagy of AML cells by negatively regulating the phosphorylation and activation of AKT/mTOR. By the way, SATB1 may negatively target regulates IER3 transcription.

Proteomic analysis identifies argininosuccinate synthetase 1 and special AT-rich sequence binding protein 1 as reliable markers for the immunohistochemical distinction between WHO types A and B3 thymomas.

The reliable classification of type A versus type B3 thymomas has prognostic and therapeutic relevance, but can be problematic due to considerably overlapping morphology. No immunohistochemical markers aiding in this distinction have been published so far. We identified and quantified numerous differentially expressed proteins using an unbiased proteomic screen by mass spectrometry in pooled protein lysates from three type A and three type B3 thymomas. From these, candidates were validated in a larger series of paraffin-embedded type A and B3 thymomas. We identified argininosuccinate synthetase 1 (ASS1) and special AT-rich sequence binding protein 1 (SATB1) as highly discriminatory between 34 type A and 20 type B3 thymomas (94% sensitivity, 98% specificity and 96% accuracy). Although not the focus of this study, the same markers also proved helpful in the diagnosis of type AB (n = 14), B1 (n = 4) and B2 thymomas (n = 10). Mutually exclusive epithelial expression of ASS1 in 100% of type B3 thymomas and ectopic nuclear expression of SATB1 in 92% of type A thymomas support the distinction between type A and type B3 thymomas with 94% sensitivity, 98% specificity and 96% accuracy.

MiR-218-5p promotes trophoblast infiltration and inhibits endoplasmic reticulum/oxidative stress by reducing UBE3A-mediated degradation of SATB1.

This research evaluated the effects of miR-218-5p on trophoblast infiltration and endoplasmic reticulum/oxidative stress during preeclampsia (PE). The expression of miR-218-5p and special AT-rich sequence binding protein 1 (SATB1) in placental tissues from 25 patients with PE and 25 normal pregnant subjects was determined using qRT-PCR and western blotting. Cell invasion and cell migration were detected by performing Transwell assays and scratch assays, respectively. MMP-2/9, TIMP1/2, HIF-1α, p-eIF2α, and ATF4 expression in cells was assessed through western blotting. Intracellular reactive oxygen species were detected using 2,7-dichlorodihydrofluorescein diacetate, and intracellular malondialdehyde and superoxide dismutase activities were determined with kits. Dual-luciferase and RNA pull-down assays were performed to verify the interaction between miR-218-5p and UBE3A. Co-immunoprecipitation and western blotting were used to detect the ubiquitination levels of SATB1. A rat model of PE was established, and an miR-218-5p agomir was injected into rat placental tissues. The pathological characteristics of placental tissues were detected via HE staining, and MMP-2/9, TIMP1/2, p-eIF2α, and ATF4 expression in rat placental tissues was determined through western blotting. MiR-218-5p and SATB1 were expressed at low levels, while UBE3A was highly expressed in the placental tissues of patients with PE. The transfection of an miR-218-5p mimic, UBE3A shRNA, or an SATB1 overexpression vector into HTR-8/SVneo cells promoted trophoblast infiltration and inhibited endoplasmic reticulum/oxidative stress. It was determined that UBE3A is a target of miR-218-5p; UBE3A induces ubiquitin-mediated degradation of SATB1. In PE model rats, miR-218-5p alleviated pathological features, promoted trophoblast infiltration, and inhibited endoplasmic reticulum/oxidative stress. MiR-218-5p targeted and negatively regulated UBE3A expression to inhibit ubiquitin-mediated SATB1 degradation, promote trophoblast infiltration, and inhibit endoplasmic reticulum/oxidative stress.

Increased GS-II lectin binding and SATB2 downregulation are biological features for sessile serrated lesions and microvesicular hyperplastic polyps.

Sessile serrated lesions (SSLs) and microvesicular hyperplastic polyps (MVHPs) are colorectal lesions displaying gastric differentiation. Griffonia simplicifolia-II (GS-II) is a lectin specific to terminal α/βGlcNAc residues. Here, we assessed GS-II binding and performed immunostaining for HIK1083 (specific to terminal αGlcNAc residues), MUC5AC, MUC6, and special AT-rich sequence binding protein 2 (SATB2) in SSLs, MVHPs, and tubular adenomas (TAs). We observed MUC5AC positivity in 28 of 30 SSLs, but in only three of 23 TAs. Moreover, 24 of 30 SSLs were MUC6-positive, while none of the 23 TAs were MUC6-positive. None of the 30 SSLs or 23 TAs showed HIK1083 positivity. All 30 SSLs and 26 MVHPs were GS-II-positive, while only seven of 23 were in TAs. GS-II staining was mainly distributed in the Golgi region, but SSLs and MVHPs showed goblet cell distribution, in 20 of 30 and 19 of 26 cases, respectively. All SSLs, MVHPs, and TAs were SATB2-positive, but 21 of 30 SSLs and 12 of 26 MVHPs showed decreased staining intensity relative to adjacent mucosa, a decrease seen in only two of 23 in TAs. These results indicate overall that increased terminal βGlcNAc and decreased SATB2 expression are characteristics of SSLs and MVHPs.

SATB1 regulates 3D genome architecture in T cells by constraining chromatin interactions surrounding CTCF-binding sites

Special AT-rich sequence binding protein 1 (SATB1) has long been proposed to act as a global chromatin loop organizer in Tcells. However, the exact functions of SATB1 in spatial genome organization remain elusive. Here we show that the depletion of SATB1 in human and murine Tcells leads to transcriptional dysregulation for genes involved in Tcell activation, as well as alterations of 3D genome architecture at multiple levels, including compartments, topologically associating domains, and loops. Importantly, SATB1 extensively colocalizes with CTCF throughout the genome. Depletion of SATB1 leads to increased chromatin contacts among and across the SATB1/CTCF co-occupied sites, thereby affecting the transcription of critical regulators of Tcell activation. The loss of SATB1 does not affect CTCF occupancy but significantly reduces the retention of CTCF in the nuclear matrix. Collectively, our data show that SATB1 contributes to 3D genome organization by constraining chromatin topology surrounding CTCF-binding sites.

Special AT-rich sequence binding protein 1 promotes multidrug resistance in gastric cancer by regulation of Ezrin to alter subcellular localization of ATP-binding cassette transporters.

Multidrug resistance is a primary factor in the poor response to chemotherapy and subsequent death in gastric cancer patients. However, the molecular mechanisms involved remain unclear. In this study, the high expression of special AT-rich sequence binding protein 1 (SATB1) in gastric cancer was found to be associated with reduced sensitivity to various chemotherapy drugs. Our results demonstrate that SATB1 can promote chemotherapy resistance in gastric cancer in vitro and in vivo. SATB1 exerts its effect by enhancing the activity of multiple ATP-binding cassette (ABC) transporters (P-glycoprotein, multidrug resistance-associated protein, and breast cancer resistance protein) in gastric cancer cell lines. We also found that SATB1 affects ABC transporters by altering the subcellular localization of the ABC transporter rather than its expression. Subsequently, we confirmed that Ezrin binds to various ABC transporters and affects their subcellular localization. In addition, we found that SATB1 can also bind to the Ezrin promoter and regulate its expression. In the present study, we elucidate the mechanism of SATB1-mediated multidrug resistance in gastric cancer, providing a basis for SATB1 as a potential target for reversal of resistance.

Immunohistochemical Expression Profile of SATB2 in Colorectal Adenocarcinoma and Association with Clinicopathological Parameters

Introduction: Colorectal carcinoma is the third most common cancer worldwide. Several clinicopathological parameters act as prognostic factors in colorectal carcinoma, but only a few are helpful in predicting the treatment outcome. Therefore, there is a need for better prognostic markers which also aids in assessing treatment benefits in colorectal carcinoma patients. Special AT Rich Sequence Binding Protein 2 (SATB2) is a highly specific marker for colorectal tissue. Decreased expression of SATB2 is also associated with poor prognosis in colorectal carcinoma. Aim: To analyse the histomorphology, immunohistochemical expression profile of SATB2 and association with clinicopathological parameters in colorectal adenocarcinoma. Materials and Methods: The cross-sectional study included 84 cases of colorectal carcinoma received in the Department of Pathology, SRM Medical College Hospital and Research Centre, Kattankulathur, Chennai, Tamil Nadu, India, in the period between April 2021 to September 2022. Both biopsy and resected specimens were included in the study. Relevant clinical data was collected. Histological diagnosis, grading and staging of the tumour was done using Haematoxylin and Eosin (H&E) slides as described and tabulated. Immunohistochemistry (IHC) for SATB2 and was done and expression profile compared with the clinicopathological parameters to assess prognostic significance. Data was analysed using software-Statistical Package for Social Sciences (SPSS, version 23.0). Results: Out of the 84 cases, 42 were biopsy and 42 resected specimens. Mean age of the patients in the study was 57.9 years. Patients were predominantly males (n=51, 60.7%) with a male:female ratio of 1.54:1. Of the 84 cases, 40.5% (n=34) had tumour located in the rectum. Majority of the cases were moderately differentiated adenocarcinoma (n=48, 57.1%). Predominantly, stage III tumours (n=33, 39.3%) were noted. Out of the tumours showing decreased expression of SATB2, 55% (n=22) were left-sided tumours, metastasis was seen in 60% (n=24 cases), 37.5% of cases (n=9) showed lymphovascular invasion, and 55% (n=22) had a stage III tumour. Conclusion: The present study results indicate that a decrease in SATB2 expression is associated with presence of lymphovascular invasion, perineural invasion, regional and distant metastasis and a higher pathological stage which signifies poor prognosis in colorectal carcinoma. These aid the physician for risk stratification of patients and enable personalised treatment choices including adjuvant chemotherapy in high-risk groups.

Peripheral Blood of Vitiligo Patients-Derived Exosomal MiR-21-5p Inhibits Melanocytes Melanogenesis via Targeting SATB1.

Vitiligo is a common depigmentation disease characterized by progressive destruction and disappearance of epidermal melanocytes. Exosomes have been discovered to regulate the pigment status of melanocytes. We aimed to explore the role of exosomes from peripheral blood of vitiligo patients on melanogenesis. Human melanocytes cell line PIG1 was treated with exosomes from the healthy volunteers or exosomes from the vitiligo patients referred to the Department of Dermatology, Children's Hospital Affiliated to Zhengzhou University, China and transfected with miR-21-5p mimic or inhibitor. Exosome labeling assay was used to assess whether exosomes were absorbed by melanocytes. Melanin content and tyrosinase activity assays were performed to investigate melanogenesis in melanocytes. The levels of melanogenesis-related genes and proteins were detected by RT-qPCR and western blot assays. Dual-luciferase reporter assay was performed to confirm the relationship between miR-21-5p and special AT-rich sequence binding protein-1 (SATB1). Exosomes from peripheral blood of vitiligo patients were transferred into melanocytes and suppressed melanin content, tyrosinase activity and melanogenesis-related genes and proteins levels. Besides, miR-21-5p was highly expressed in exosomes from peripheral blood of vitiligo patients. The results of the gain- and loss-of-function experiments demonstrated that miR-21-5p inhibited the melanogenesis of melanocytes. Furthermore, miR-21-5p inhibitor abolished the inhibitory role of exosomes from peripheral blood of vitiligo patients. Subsequently, miR-21-5p directly targeted SATB1 in melanocytes. Furthermore, overexpression of SATB1 reversed the inhibitory roles of miR-21-5p mimic on melanin content, tyrosinase activity, and melanogenesis-related protein expression. Peripheral blood of vitiligo patients-derived exosomal miR-21-5p inhibited melanocytes melanogenesis via targeting SATB1.

Immunohistochemical Characterization of Gingival Fibromas.

Gingival fibromas (GFs) are fibrous lesions of the gingiva that are not well defined in the literature. They are histologically similar to peripheral ossifying fibromas (POFs), both being characterized as cellular proliferations of dense fibrous tissue, with POFs differing in that they demonstrate foci of calcification. This study aims to expand upon the immunohistochemical characterization of GFs, and to confirm their osteoblastic phenotype. Formalin fixed, paraffin embedded GFs, POFs and fibroepithelial polyps (FEPs) of the gingiva were examined. Immunohistochemical staining was performed for special AT-rich sequence binding protein 2 (SATB2), runt-related transcription factor 2 (RUNX2), osteocalcin and alpha-smooth muscle actin (αSMA). Sections were evaluated by light microscopy and the immunohistochemical staining patterns were assigned immunoreactive scores (IRS) based on percentage of stained cells and intensity of staining. GFs, POFs, and FEPs of the gingiva expressed osteoblastic markers SATB2, RUNX2 and osteocalcin. GFs and POFs expressed αSMA while FEPs of the gingiva did not. GFs and POFs had similar staining patterns of SATB2, RUNX2 and αSMA. These findings demonstrate that GFs and POFs exhibit a similar immunohistochemical profile, and supports a theory that GFs are osteoblastic lesions possibly related to POFs.

Alcohol promotes epithelial mesenchymal transformation-mediated premetastatic niche formation of colorectal cancer by activating interaction between laminin-γ2 and integrin-β1.

BACKGROUNDColorectal cancer (CRC) is a common malignant tumor. Alcohol consumption is positively correlated with CRC malignant metastasis; however, the mechanism is unclear. The interaction between laminin-γ2 (LAMC2) and integrin-β1 (ITGB1) plays a role in premetastatic niche signaling, which may induce epithelial mesenchymal transformation (EMT) and lead to metastasis.AIMTo investigate the effects of alcohol on CRC metastasis from the molecular mechanism of the premetastatic niche.METHODSThe interaction between LAMC2 and ITGB1 was measured by Duolink assay, and the expression levels of LAMC2, ITGB1 and focal adhesion kinase (FAK), snail, fibronectin, N-cadherin and special AT-rich sequence binding protein 1 (SATB1) were measured by quantitative real-time polymerase chain reaction, immunohistochemistry and western blotting. Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and IL-6 levels were measured via enzyme-linked immunosorbent assay, histopathological assessment via hematoxylin eosin staining, and determination of aberrant crypt foci via methylene blue.RESULTSThe lymph node metastasis rate was higher in the alcohol group than non-alcohol group. There was a significant increase in interaction signals between LAMC2 and ITGB1, and an increase in phosphorylate-FAK/FAK, snail, fibronectin, N-cadherin and SATB1, whereas E-cadherin was reduced in the alcohol group compared to the non-alcohol group in both animal and clinical samples. Serum IL-1β, TNF-α and IL-6 were higher in alcohol group than in non-alcohol group. Alcohol may promote CRC metastasis by influencing the molecular mechanism of the premetastatic niche.CONCLUSIONOur study suggests that alcohol promotes EMT-mediated premetastatic niche formation of CRC by activating the early interaction between LAMC2 and ITGB1 and lead to CRC metastasis.