Sox9 Promoter Research Articles

KAT6B is required for histone 3 lysine 9 acetylation and SOX gene expression in the developing brain.

Heterozygous mutations in the histone lysine acetyltransferase gene KAT6B (MYST4/MORF/QKF) underlie neurodevelopmental disorders, but the mechanistic roles of KAT6B remain poorly understood. Here, we show that loss of KAT6B in embryonic neural stem and progenitor cells (NSPCs) impaired cell proliferation, neuronal differentiation, and neurite outgrowth. Mechanistically, loss of KAT6B resulted in reduced acetylation at histone H3 lysine 9 and reduced expression of key nervous system development genes in NSPCs and the developing cortex, including the SOX gene family, in particular Sox2, which is a key driver of neural progenitor proliferation, multipotency and brain development. In the fetal cortex, KAT6B occupied the Sox2 locus. Loss of KAT6B caused a reduction in Sox2 promoter activity in NSPCs. Sox2 overexpression partially rescued the proliferative defect of Kat6b -/- NSPCs. Collectively, these results elucidate molecular requirements for KAT6B in brain development and identify key KAT6B targets in neural precursor cells and the developing brain.

Surface tension enables induced pluripotent stem cell culture in commercially available hardware during spaceflight

Low Earth Orbit (LEO) has emerged as a unique environment for evaluating altered stem cell properties in microgravity. LEO has become increasingly accessible for research and development due to progress in private spaceflight. Axiom Mission 2 (Ax-2) was launched as the second all-private astronaut mission to the International Space Station (ISS). Frozen human induced pluripotent stem cells (hiPSCs) expressing green fluorescent protein (GFP) under the SOX2 promoter, as well as fibroblasts differentiated from SOX2-GFP hiPSCs, were sent to the ISS. Astronauts then thawed and seeded both cell types into commercially available 96-well plates, which provided surface tension that reduced fluid movement out of individual wells and showed that hiPSCs or hiPSC-derived fibroblasts could survive either in suspension or attached to a Matrigel substrate. Furthermore, both cell types could be transfected with red fluorescent protein (RFP)-expressing plasmid. We demonstrate that hiPSCs and hiPSC-fibroblasts can be thawed in microgravity in off-the-shelf, commercially-available cell culture hardware, can associate into 3D spheroids or grow adherently in Matrigel, and can be transfected with DNA. This lays the groundwork for future biomanufacturing experiments in space.

SOX9 promotes hypoxic pulmonary hypertension through stabilization of DPP4 in pulmonary artery smooth muscle cells

Pulmonary hypertension (PH) is a progressive cardiopulmonary disorder characterized by pulmonary vascular remodeling (PVR), primarily due to the excessive proliferation of pulmonary artery smooth muscle cells (PASMCs). This study aimed to investigate the role and molecular mechanism of SOX9 in hypoxic PH in rats. The findings revealed that SOX9 was upregulated in the pulmonary arteries and PASMCs of hypoxia-exposed rats. SOX9 knockdown inhibited hypoxia-induced proliferation and migration of PASMCs, reduced PVR, and subsequently alleviated hypoxia-induced PH in rats, suggesting that SOX9 plays a critical role in PH. Further investigation demonstrated that SOX9 interacted with DPP4, preventing its ubiquitin degradation in hypoxia-exposed PASMCs. DPP4 knockdown inhibited hypoxia-induced PASMC proliferation and migration, and administration of the DPP4 inhibitor sitagliptin (5 mg/kg) significantly reduced PVR and alleviated hypoxia-induced PH in rats, indicating that SOX9 contributes to PH by stabilizing DPP4. The results also showed that hypoxia induced YAP1 expression and dephosphorylation, leading to YAP1 nuclear localization. YAP1 knockdown promoted the degradation of HIF-1α in hypoxia-exposed PASMCs and inhibited hypoxia-induced proliferation and migration of PASMCs. Additionally, HIF-1α, as a transcription factor, promoted SOX9 expression by binding to the SOX9 promoter in hypoxia-exposed PASMCs. In conclusion, hypoxia promotes the proliferation and migration of PASMCs through the regulation of the YAP1/HIF-1α/SOX9/DPP4 signaling pathway, leading to PH in rats. These findings suggest that SOX9 may serve as a potential prognostic marker and therapeutic target for PH.

Epigenetic mechanisms of Nsd1-mediated histone methylation modifications in chondrocyte ferroptosis in knee osteoarthritis.

Knee osteoarthritis (KOA) is a degenerative joint disease characterized by pain, stiffness, and impaired mobility, with current therapies offering limited efficacy. This study investigates the epigenetic role of nuclear receptor-binding SET domain protein 1 (NSD1) in KOA pathogenesis. A KOA mouse model was established, and adenoviral vectors were employed to upregulate Nsd1 and inhibit SRY-box transcription factor 9 (Sox9), followed by histopathological assessments. We examined changes in cell morphology, proliferation, viability, and ferroptosis-related markers. The expression of Nsd1, Sox9, and acyl-CoA synthetase long-chain family member 4 (Acsl4) was analyzed, along with the enrichment of Nsd1 and dimethylated lysine 36 of histone 3 (H3K36me2) on the Sox9 promoter and Sox9 on the Acsl4 promoter. Additionally, the binding relationship between Sox9 and the Acsl4 promoter sequence was analyzed. Our results revealed that Nsd1 expression was reduced in KOA mouse tissues and interleukin (IL)-1β-stimulated chondrocytes. Nsd1 upregulation alleviated KOA, promoted chondrocyte proliferation and viability, and inhibited ferroptosis. Mechanistically, Nsd1 enhanced H3K36me2 to upregulate Sox9 expression, which in turn suppressed Acsl4 expression and ferroptosis. Sox9 inhibition partially reversed the protective effect of Nsd1 overexpression. In summary, Nsd1 upregulation mitigates chondrocyte ferroptosis and ameliorates KOA by modulating H3K36me2 to upregulate Sox9 and downregulate Acsl4 expression.

FOSL1 promotes stem cell‑like characteristics and anoikis resistance to facilitate tumorigenesis and metastasis in osteosarcoma by targeting SOX2.

Metastasis is the leading cause of cancer‑related death in osteosarcoma (OS). OS stem cells (OSCs) and anoikis resistance are considered to be essential for tumor metastasis formation. However, the underlying mechanisms involved in the maintenance of a stem‑cell phenotype and anoikis resistance in OS are mostly unknown. Fos‑like antigen 1 (FOSL1) is important in maintaining a stem‑like phenotype in various cancers; however, its role in OSCs and anoikis resistance remains unclear. In the present study, the dynamic expression patterns of FOSL1 were investigated during the acquisition of cancer stem‑like properties using RNA sequencing, PCR, western blotting and immunofluorescence. Flow cytometry, tumor‑sphere formation, clone formation assays, anoikis assays, western blotting and in vivo xenograft and metastasis models were used to further investigate the responses of the stem‑cell phenotype and anoikis resistance to FOSL1 overexpression or silencing in OS cell lines. The underlying molecular mechanisms were evaluated, focusing on whether SOX2 is crucially involved in FOSL1‑mediated stemness and anoikis in OS. FOSL1 expression was observed to be upregulated in OSCs and promoted tumor‑sphere formation, clone formation and tumorigenesis in OS cells. FOSL1 expression correlated positively with the expression of stemness‑related factors (SOX2, NANOG, CD117 and Stro1). Moreover, FOSL1 facilitated OS cell anoikis resistance and promoted metastases by regulating the expression of apoptosis related proteins BCL2 and BAX. Mechanistically, FOSL1 upregulated SOX2 expression by interacting with the SOX2 promoter and activating its transcription. The results also showed that SOX2 is critical for FOSL1‑mediated stem‑like properties and anoikis resistance. The current findings indicated that FOSL1 is an important regulator that promotes a stem cell‑like phenotype and anoikis resistance to facilitate tumorigenesis and metastasis in OS by regulating the transcription of SOX2. Thus, FOSL1 might represent an attractive target for therapeutic interventions in OS.

Rev-erbα regulate neurogenesis through suppression of Sox2 in neuronal cells to regenerate dopaminergic neurons and abates MPP+ induced neuroinflammation

Parkinson's disease is a progressive neurodegenerative disease that affects the motor and non-motor circuits of the brain. Currently, there are no promising therapeutic measures for Parkinson's disease, and most strategies designed to alleviate the Parkinson's disease are palliative. The dearth of therapeutic interventions in Parkinson's disease has driven attention in the search for targets that may augment dopamine secretion, promote differentiation towards dopaminergic neuronal lineage, or aid in neuroprotection from neuronal stress and inflammation, and prevent Parkinson's disease associated motor impairment and behavioural chaos.The study first reports that Rev-erbα plays an important role in regulating the differentiation of undifferentiated neuronal cells towards dopaminergic neurons through abating Sox2 expression in human SH-SY5Y cells. Rev-erbα directly binds to the human Sox2 promoter region and represses their expression to promote differentiation towards dopaminergic neurons. We have reported a novel mechanism of Rev-erbα which effectively abrogates 1-methyl-4-phenylpyridinium induced cytotoxicity, inflammation, and oxidative stress, exerted a beneficial effect on transmembrane potential, and suppressed apoptosis in the neuronal in vitro model of Parkinson's disease.Rev-erbα ligand SR9011 was observed to ease the disease severity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced mouse model of Parkinson's disease. Rev-erbα alleviates the locomotor behavioural impairment, prevents cognitive decline and promotes motor coordination in mice. Administration of Rev-erbα ligand also helps in replenishing the dopaminergic neurons and abrogating the neurotoxin mediated toxicity in an in vitro and in vivo Parkinson's disease model.We conclude that Rev-erbα emerges as a moonlighting nuclear receptor that could be targeted in the treatment and alleviation of Parkinson disease.

LncRNA DERCNC in Hepatocellular Carcinoma with Cirrhosis Aggravates Tumor Proliferation by Targeting SOX9.

This study aims to understand the role of cirrhosis in promoting hepatocellular carcinoma (HCC) progression by analyzing the differential expression of long noncoding RNAs (lncRNAs) between cirrhotic hepatocellular carcinoma (CHCC) and noncirrhotic hepatocellular carcinoma (NCHCC). A transcriptional profile array was used to identify differentially expressed lncRNAs. Subsequently, a specific lncRNA was selected to evaluate the clinical significance, potential functions, regulatory targets, and pathways through both in vitro and in vivo experiments. The study identified a lncRNA, which we termed DERCNC, an acronym for Differentially Expressed RNA between Cirrhotic and Non-Cirrhotic HCC. DERCNC was significantly more highly expressed in CHCC than in NCHCC. Clinically, elevated levels of DERCNC expression were positively correlated with both the cirrhotic state and tumor stage and inversely correlated with tumor differentiation. Furthermore, high expression of DERCNC was associated with a poor prognosis for patients. Conditioned medium from the hepatic stellate cell (LX2) was found to enhance DERCNC expression, SOX9 expression, and tumor proliferation. Overexpression of DERCNC similarly promoted tumor proliferation and increased SOX9 levels. Conversely, DERCNC silencing resulted in the opposite effects. Moreover, the pro-proliferative function of DERCNC was reversible through the modulation of SOX9 expression. Further mechanistic studies revealed that DERCNC upregulated SOX9 by increasing the enrichment of H3K27ac modifications near the SOX9 promoter. In conclusion, DERCNC expression in CHCC has significant clinical implications and can aggravate tumor proliferation by targeting SOX9. This represents a novel mechanism by which cirrhosis promotes tumor progression.

Suppress the cell growth of cancer stem-like cells (NTERA-2) using Sox2-Oct4 decoy oligodeoxynucleotide−encapsulated niosomes-zinc hybrid nanocarriers under X-irradiation

Sox2 and Oct4 dysregulations could significantly increase in the cancer stem cell (CSC) population in some cancer cells and resistance to common treatments. In this study, the synergistic effects of Sox2-Oct4 decoy oligodeoxynucleotides-encapsulated Niosomes-zinc hybrid nanocarriers along with X‐irradiation conditions as a combinational therapy tool were investigated in the treatment of cancer-like stem cells (NTERA-2). The NTERA-2 cell line known as a cancer-like stem cell line was used in this investigation. Sox2-Oct4 decoy oligodeoxynucleotides were designed based on the sequence of the Sox2 promoter and synthesized. Physicochemical characteristics of ODNs-encapsulated niosomes-zinc hybrid nanocarriers (NISM@BSA-DEC-Zn) investigated with FT-IR, DLS, FESEM, and ODNs release kinetic estimation assays. Further investigations such as hemolysis, uptake, cell viability, apoptosis, cell cycle, and scratch repair tests were performed. All the above assays were completed with and without X-ray exposure conditions (fractionated 2Gy). Physicochemical characteristics results showed that the Niosomes-Zn nanocarriers were successfully synthesized. NISM@BSA-DEC-Zn was efficiently taken up by NTERA-2 cells and significantly inhibited cell growth, increased apoptosis, and reduced cell migration in both conditions (with and without X-ray exposure). Furthermore, NISM@BSA-DEC-Zn treatment resulted in G1 and G2/M cell cycle arrest without and with X-irradiation, respectively. The prepared nanocarrier system can be a promising tool for drug delivery in cancer treatment. Decoy ODN strategy along with zinc nanoparticles could increase the sensitivity of cancer cells toward irradiation, which has the potential for combinational cancer therapies.

Study on chromatin regulation patterns of expression vectors in the PhiC31 integration site

ABSTRACT The PhiC31 integration system allows for targeted and efficient transgene integration and expression by recognizing pseudo attP sites in mammalian cells and integrating the exogenous genes into the open chromatin regions of active chromatin. In order to investigate the regulatory patterns of efficient gene expression in the open chromatin region of PhiC31 integration, this study utilized Ubiquitous Chromatin Opening Element (UCOE) and activating RNA (saRNA) to modulate the chromatin structure in the promoter region of the PhiC31 integration vector. The study analysed the effects of DNA methylation and nucleosome occupancy changes in the integrated promoter on gene expression levels. The results showed that for the OCT4 promoter with moderate CG density, DNA methylation had a smaller impact on expression compared to changes in nucleosome positioning near the transcription start site, which was crucial for enhancing downstream gene expression. On the other hand, for the SOX2 promoter with high CG density, increased methylation in the CpG island upstream of the transcription start site played a key role in affecting high expression, but the positioning and clustering of nucleosomes also had an important influence. In conclusion, analysing the DNA methylation patterns, nucleosome positioning, and quantity distribution of different promoters can determine whether the PhiC31 integration site possesses the potential to further enhance expression or overcome transgene silencing effects by utilizing chromatin regulatory elements.

Abstract 7574: Exploring the therapeutic potential of proteasome inhibitors in targeting SOX2-driven LUSC and SCLC

Abstract This study addresses the current lack of small molecules targeting SOX2, a pivotal protein in cancer, through an examination of the effectiveness of FDA-approved drugs and proteasome inhibitors. Building on prior research demonstrating the proteasome inhibitor CFZ's capacity to diminish the expression of ITGB4 and PXN in LUAD effectively, our investigation highlights CFZ and IXA as potent inhibitors at nanomolar concentrations. Notably, CFZ treatment enhances sensitivity to cisplatin by suppressing the expression of ITGB4 and the stemness-associated gene SOX2.At a mechanistic level, CFZ hinders histone acetylation at the SOX2 promoter site, leading to rapid and specific downregulation. RNA-seq analysis of COH2 cells treated with CFZ unveils substantial downregulation of genes related to transcription and DNA binding. Z score analysis further reveals a noteworthy inhibition of key transcription factors (TFs), including SOX2, NANOG, POU5F1, SALL4, and KLF4. This TF inhibition extends to neuroendocrine cell lines, identifying 16 overlapping targets of SOX2 associated with stemness. These findings suggest a potential therapeutic approach for targeting cisplatin-resistant cancer stem cells across various cancer types. Moreover, the study proposes a synergistic effect of cisplatin and CFZ in mitigating the growth of neuroendocrine phenotype, SCLC. Given the limited medical options currently available for this phenotype, this insight holds particular significance. In conclusion, our study unveils CFZ as a potent transcriptional suppressor of SOX2, providing a novel strategy to sensitize cisplatin-resistant cancer stem cells. The results underscore the interplay of genetic and non-genetic mechanisms in drug resistance, emphasizing the significance of repurposing drugs for other indications. Citation Format: Atish Mohanty, Linlin Guo, Sravani Ramisetty, Sharad Singhal, Erminia Massarelli, Prakash Kulkarni, Ravi Salgia. Exploring the therapeutic potential of proteasome inhibitors in targeting SOX2-driven LUSC and SCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7574.

MiR-290 Family Maintains Pluripotency and Self-Renewal by Regulating MAPK Signaling Pathway in Intermediate Pluripotent Stem Cells.

Mouse embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs) are derived from pre- and post-implantation embryos, representing the initial "naïve" and final "primed" states of pluripotency, respectively. In this study, novel reprogrammed pluripotent stem cells (rPSCs) were induced from mouse EpiSCs using a chemically defined medium containing mouse LIF, BMP4, CHIR99021, XAV939, and SB203580. The rPSCs exhibited domed clones and expressed key pluripotency genes, with both X chromosomes active in female cells. Furthermore, rPSCs differentiated into cells of all three germ layers in vivo through teratoma formation. Regarding epigenetic modifications, the DNA methylation of Oct4, Sox2, and Nanog promoter regions and the mRNA levels of Dnmt3a, Dnmt3b, and Dnmt1 were reduced in rPSCs compared with EpiSCs. However, the miR-290 family was significantly upregulated in rPSCs. After removing SB203580, an inhibitor of the p38 MAPK pathway, the cell colonies changed from domed to flat, with a significant decrease in the expression of pluripotency genes and the miR-290 family. Conversely, overexpression of pri-miR-290 reversed these changes. In addition, Map2k6 was identified as a direct target gene of miR-291b-3p, indicating that the miR-290 family maintains pluripotency and self-renewal in rPSCs by regulating the MAPK signaling pathway.

Genetic Ablation of STE20-Type Kinase MST4 Does Not Alleviate Diet-Induced MASLD Susceptibility in Mice.

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its advanced subtype, metabolic dysfunction-associated steatohepatitis (MASH), have emerged as the most common chronic liver disease worldwide, yet there is no targeted pharmacotherapy presently available. This study aimed to investigate the possible in vivo function of STE20-type protein kinase MST4, which was earlier implicated in the regulation of hepatocellular lipotoxic milieu in vitro, in the control of the diet-induced impairment of systemic glucose and insulin homeostasis as well as MASLD susceptibility. Whole-body and liver-specific Mst4 knockout mice were generated by crossbreeding conditional Mst4fl/fl mice with mice expressing Cre recombinase under the Sox2 or Alb promoters, respectively. To replicate the environment in high-risk subjects, Mst4-/- mice and their wild-type littermates were fed a high-fat or a methionine-choline-deficient (MCD) diet. Different in vivo tests were conducted in obese mice to describe the whole-body metabolism. MASLD progression in the liver and lipotoxic damage to adipose tissue, kidney, and skeletal muscle were analyzed by histological and immunofluorescence analysis, biochemical assays, and protein and gene expression profiling. In parallel, intracellular fat storage and oxidative stress were assessed in primary mouse hepatocytes, where MST4 was silenced by small interfering RNA. We found that global MST4 depletion had no effect on body weight or composition, locomotor activity, whole-body glucose tolerance or insulin sensitivity in obese mice. Furthermore, we observed no alterations in lipotoxic injuries to the liver, adipose, kidney, or skeletal muscle tissue in high-fat diet-fed whole-body Mst4-/- vs. wild-type mice. Liver-specific Mst4-/- mice and wild-type littermates displayed a similar severity of MASLD when subjected to an MCD diet, as evidenced by equal levels of steatosis, inflammation, hepatic stellate cell activation, fibrosis, oxidative/ER stress, and apoptosis in the liver. In contrast, the in vitro silencing of MST4 effectively protected primary mouse hepatocytes against ectopic lipid accumulation and oxidative cell injury triggered by exposure to fatty acids. In summary, these results suggest that the genetic ablation of MST4 in mice does not mitigate the initiation or progression of MASLD and has no effect on systemic glucose or insulin homeostasis in the context of nutritional stress. The functional compensation for the genetic loss of MST4 by yet undefined mechanisms may contribute to the apparent discrepancy between in vivo and in vitro phenotypic consequences of MST4 silencing.

Abnormal Innervation, Demyelination, and Degeneration of Spiral Ganglion Neurons as Well as Disruption of Heminodes are Involved in the Onset of Deafness in Cx26 Null Mice.

GJB2 gene mutations are the most common causes of autosomal recessive non-syndromic hereditary deafness. For individuals suffering from severe to profound GJB2-related deafness, cochlear implants have emerged as the sole remedy for auditory improvement. Some previous studies have highlighted the crucial role of preserving cochlear neural components in achieving favorable outcomes after cochlear implantation. Thus, we generated a conditional knockout mouse model (Cx26-CKO) in which Cx26 was completely deleted in the cochlear supporting cells driven by the Sox2 promoter. The Cx26-CKO mice showed severe hearing loss and massive loss of hair cells and Deiter's cells, which represented the extreme form of human deafness caused by GJB2 gene mutations. In addition, multiple pathological changes in the peripheral auditory nervous system were found, including abnormal innervation, demyelination, and degeneration of spiral ganglion neurons as well as disruption of heminodes in Cx26-CKO mice. These findings provide invaluable insights into the deafness mechanism and the treatment for severe deafness in Cx26-null mice.

THE ROLE OF HISTONE MODIFIERS AND OXIDATIVE STRESS IN OSTEOARTHRITIS

Development of osteoarthritis (OA) correlates with epigenetic alteration in chondrocytes. H3K27me3 demethylase UTX is known to regulate tissue homeostasis, but its role in the homeostasis of articulating joint tissue is poorly understood. Forced UTX expression upregulated H3K27me3 enrichment at the Sox9 promoter region to inhibit key extracellular matrix (ECM) molecules, like e.g. type II collagen, aggrecan, and glycosaminoglycans in articular chondrocytes. Utx loss in vitro altered the H3K27me3-binding epigenomic landscape, which contributes to mitochondrial activity, cellular senescence, and cartilage development. Functional target genes of Utx comprise insulin-like growth factor 2 (Igf2) and polycomb repressive complex 2 (PRC2) core components Eed and Suz12. Specifically, Utx deletion promoted Tfam transcription, mitochondrial respiration, ATP production and Igf2 transcription, but inhibited Eed and Suz12 expression. Igf2 inhibition or forced Eed or Suz12 expression increased H3K27 trimethylation and H3K27me3 enrichment at the Sox9 promoter, compromising Utx loss-induced ECM overproduction. Overexpression of Utx in murine knee joints aggravated OA development, including articular cartilage damage, synovitis, osteophyte formation, and subchondral bone loss. Transgenic mice with a chondrocytespecific Utx knockout develop thicker articular cartilage as compared to wild-type controls and show fewer gonarthrotic symptoms during destabilized medial meniscus- and collagenase-induced joint injury. In summary, UTX represses chondrocytic activity and accelerates cartilage degradation during OA, while Utx loss promotes cartilage integrity through epigenetic stimulation of mitochondrial biogenesis and Igf2 transcription. This highlights a novel noncanonical role of Utx that regulates articular chondrocyte anabolism and OA development.

METTL3-stabilized super enhancers-lncRNA SUCLG2-AS1 mediates the formation of a long-range chromatin loop between enhancers and promoters of SOX2 in metastasis and radiosensitivity of nasopharyngeal carcinoma.

Super enhancers (SE) play pivotal roles in cell identity and diseases occur including tumorigenesis. The depletion of SE-associated lncRNA transcripts, also known as super-lncRNA, causes the activity of SE to be dysregulated. We screened and identified an elevated metastasis-associated SE-lncRNA SUCLG2-AS1 in nasopharyngeal carcinoma (NPC) using RNA-sequencing, real-time quantitative polymerase chain reaction (RT-qPCR) and bioinformatics. Western blotting, RT-qPCR, methylated RNA immunoprecipitation (MeRIP), RNA immunoprecipitation, chromatin immunoprecipitation, RNA pull-down and 3C (chromosome conformation capture assays) were used for mechanistic studies. SUCLG2-AS1 was correlated with a poor prognosis. SUCLG2-AS1 promotes NPC cell invasion and metastasis while repressing apoptosis and radiosensitivity in vitro and in vivo. Mechanistically, high SUCLG2-AS1 expression occurred in an m6A-dependent manner. SUCLG2-AS1 was found to be located in the SE region of SOX2, and it regulated the expression of SOX2 via long-range chromatin loop formation, which via mediating CTCF (transcription factor) occupied the SE and promoter region of SOX2, thus regulating the metastasis and radiosensitivity of NPC. Taken together, our data suggest that SUCLG2-AS1 may serve as a novel intervention target for the clinical treatment of NPC.

Overexpression of SOX2 Gene by Histone Modifications: SOX2 Enhances Human Prostate and Breast Cancer Progression by Prevention of Apoptosis and Enhancing Cell Proliferation

Introduction: SOX2 plays a crucial role in tumor development, cancer stem cell maintenance, and cancer progression. Mechanisms of SOX2 gene regulation in human breast and prostate cancers are not established yet. Methods: SOX2 expression in prostate and breast cancer tissues and cell lines was determined by qRT-PCR, Western blot, and immunochemistry, followed by the investigation of pro-tumorigenic properties like cell proliferation, migration, and apoptosis by gene knockdown and treatment with epigenetic modulators and ChIP. Results: Prostate and breast cancer tissues showed very high expression of SOX2. All cancer cell lines DU145 and PC3 (prostate) and MCF7 and MDA-MB-231 (breast) exhibited high expression of SOX2. Inhibition of SOX2 drastically decreased cell proliferation and migration. Epigenetic modulators enhanced SOX2 gene expression in both cancer types. DNA methylation pattern in SOX2 promoter could not be appreciably counted for SOX2 overexpression. Activation of SOX2 gene promoter was due to very high deposition of H3K4me3 and H3K9acS10p and drastic decrease of H3K9me3 and H3K27me3. Conclusion: Histone modification is crucial for the overexpression of SOX2 during tumor development and cancer progression. These findings show the avenue of co-targeting SOX2 and its active epigenetic modifier enzymes to effectively treat aggressive prostate and breast cancers.

Etv5a suppresses neural progenitor cell proliferation by inhibiting sox2 transcription.

Neural progenitor cells are self-renewable, proliferative, and multipotent cell populations that generate diverse types of neurons and glia to build the nervous system. Transcription factors play critical roles in regulating various cellular processes; however, the transcription factors that regulate the development of neural progenitors are yet to be identified. In the present study, we demonstrated that zebrafish etv5a is expressed in the neural progenitor cells of the neuroectoderm. Downregulation of endogenous Etv5a function by etv5a morpholino or an etv5a dominant-negative variant increased the proliferation of sox2-positive neural progenitor cells, accompanied by inhibition of neurogenesis and gliogenesis. These phenotypes in Etv5a-depleted embryos could be rescued by co-injection with etv5a cRNA. Etv5a overexpression reduced sox2 expression. Direct binding of Etv5a to the regulatory elements of sox2 was affirmed by chromatin immunoprecipitation. These data revealed that Etv5a directly suppressed sox2 expression to reduce the proliferation of neural progenitor cells. In addition, the expression of foxm1, a putative target gene of Etv5a and a direct upstream transcription factor of sox2, was upregulated in Etv5a-deficient embryos. Moreover, the suppression of Foxm1 function by the foxm1 dominant-negative construct nullified the phenotype of upregulated sox2 expression caused by Etv5a deficiency. Overall, our results indicated that Etv5a regulates the expression of sox2 via direct binding to the sox2 promoter and indirect regulation by inhibiting foxm1 expression. Hence, we revealed the role of Etv5a in the transcriptional hierarchy that regulates the proliferation of neural progenitor cells.

Targeting ITGB4/SOX2-driven lung cancer stem cells using proteasome inhibitors

This study investigates the role of integrin β4 (ITGB4) and stemness-associated factor SOX2 in platinum resistance in lung squamous cell carcinoma (LUSC). The expression of SOX2 and ITGB4 is found to be high in all LUSC subtypes, but the impact of ITGB4 expression on overall patient survival varies by subtype. Cancer stem cells (CSCs) isolated from LUSC patients were found to be resistant to cisplatin, but knocking down ITGB4 or SOX2 sensitized them to cisplatin. Carfilzomib (CFZ) synergized with cisplatin and suppressed CSC growth by inhibiting ITGB4 and SOX2 expression. Additionally, CFZ was found to inhibit SOX2 expression epigenetically by inhibiting histone acetylation at the SOX2 promoter site. CFZ also suppressed the growth of SOX2-dependent small cell lung cancer cells invitro and invivo. The study highlights the unique function of CFZ as a transcriptional suppressor of SOX2, independent of its proteasome inhibitory function.

The transcription factors Creb1 and CEBPB regulate Sox9 promoter activity in TM4 Sertoli cells

In Sertoli cells, the Sox9 gene is essential for testicular development and normal spermatogenesis. SOX9 is critical for postnatal Sertoli cells differentiation and proliferation in the testis. However, the molecular mechanisms that specifically regulate its expression are not entirely understood. Sox9 expression is regulated by CREB1 and CEBPB in other biological contexts such as during chondrogenesis and in rat thyroid follicular cells. We hypothesized that Sox9 promoter activity is regulated by CREB1 and CEBPB in Sertoli cells. Our results show that Sox9 expression is dependent on the activation of these transcription factors by the cAMP/PKA signaling pathway in TM4 Sertoli cells. Chromatin immunoprecipitation and promoter/reporter luciferase assays with 5′ promoter deletions and site-directed mutagenesis demonstrated that CREB1 is being recruited to a DNA regulatory element at -141 bp of the Sox9 promoter region. Such regulation is dependent on the cAMP/PKA signaling pathway, resulting in phosphorylation of CREB1. Activation of Sox9 expression by CEBPB may involve its recruitment to the proximal promoter region by protein–protein interaction with CREB1. Thus, we have shown that the Sox9 promoter is being regulated by the transcription factors CREB1 and CEBPB in TM4 Sertoli cells and involve their recruitment to the proximal promoter region.

ZFP24 drives SOX9 upregulation and protects tubular epithelial cells during acute kidney injury

SOX9 is a transcription factor that controls cell-fate determination during embryonic development and adult tissue homeostasis in multiple organs including the kidneys. SOX9 expression is low in the adult kidneys, however, stress conditions can trigger its transcriptional upregulation in tubular epithelial cells. Functionally, SOX9 plays a protective role during the early phase of acute kidney injury (AKI) and facilitates repair during the recovery phase. To identify the upstream transcriptional regulators that drive SOX9 upregulation in tubular epithelial cells, here we have used an unbiased transcription factor screening approach. Our preliminary screening and validation studies show that Zinc finger protein 24 (ZFP24) controls injury induced SOX9 upregulation in tubular epithelial cells. ZFP24, a Cys2-His2 (C2H2) zinc finger protein is essential for oligodendrocyte maturation and myelination, however its role in the kidneys or in SOX9 regulation remains unknown. We find that tubular epithelial ZFP24 gene ablation exacerbates ischemia, rhabdomyolysis, and cisplatin-associated AKI. Importantly, ZFP24 gene deletion results in suppression of SOX9 upregulation in injured tubular epithelial cells. Chromatin immunoprecipitation and promoter luciferase assays confirmed that ZFP24 binds to a specific site in both murine and human SOX9 promoter. Importantly, CRISPR/Cas9 mediated introduction of mutations in the ZFP24 binding site in the SOX9 promoter in vivo led to suppression of SOX9 upregulation during AKI. These findings identify ZFP24 as a critical stress-responsive transcription factor that protects tubular epithelial cells during AKI in part through SOX9 upregulation. The current study was supported by NIDDK 1R01DK132230 grant to N.P. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.