Transcription Factor STAT3 Research Articles

LncRNA HAGLROS: A Vital Oncogenic Propellant in Various Human Cancers.

HAGLR Opposite Strand lncRNA (HAGLROS) is a long non-coding RNA (lncRNA) located on the long arm of human chromosome 2 at locus 2q31.1. Emerging evidence highlights HAGLROS as a pivotal player in human cancers, characterized by its significant upregulation across multiple malignancies where it functions as an oncogenic driver. Its aberrant expression is closely linked to the initiation and progression of 13 distinct cancer types, notably correlating with adverse clinical outcomes and reduced overall survival rates in 9 of these cancer types. Mechanistically, HAGLROS is under the regulatory influence of the transcription factor STAT3, exerts competitive binding to 9 miRNAs, activates 5 signaling pathways pivotal for cancer cell proliferation and metastasis, as well as intricately modulates gene expression profiles. Given its multifaceted roles, HAGLROS emerges as a promising candidate for cancer diagnostics and prognostics. Moreover, its potential as a therapeutic target holds considerable promise for novel treatment strategies in oncology. This review synthesizes current research on HAGLROS, covering its expression patterns, biological roles, and clinical significance in cancer. By shedding light on these aspects, this review aims to contribute new perspectives that advance our understanding of cancer biology, enhance diagnostic accuracy, refine prognostic assessments, and pave the way for targeted therapeutic interventions.

Immunomodulatory effect of mesenchymal stem cells-derived extracellular vesicles to modulate the regulatory T cells and Th1/Th2 imbalance in peripheral blood mononuclear cells of patients with allergic rhinitis.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown promising immunomodulatory capabilities for a variety of clinical conditions. However, the potential regulatory mechanisms of MSC-EVs in allergic rhinitis (AR) remain unexplored. The present study was designed to investigate the immunomodulatory effect of MSC-EVs in patients with AR. Peripheral blood mononuclear cells (PBMCs) were isolated from AR patients. The number of peripheral CD4+Foxp3+IL-17+, CD4+Foxp3+IL-17- and CD4+Foxp3-IL-17+ T cells in healthy controls and AR patients were evaluated using flow cytometry. Therapeutic effect of MSC-EVs was determined by detecting IFN-γ, IL-4, IL-17 and IL-10 cytokines in supernatant by ELISA and flow cytometry. The mean fluorescence intensity (MFI) was calculated in PBMCs for IL-10, IL-17 and TGF-β on T cells after MSC-EVs treatment. Bioinformatic analysis of microRNA was performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. CD4+Foxp3+IL-17+ T cells expression in PBMCs was higher in the AR group and the balance of Treg/Th17 was tilted towards Th17 cells. Supernatant from AR patients revealed that MSC-EVs treatment upregulated IL-10 and IFN-γ, and downregulated IL-4 and IL-17. EVs treatment effectively re-established Th1(CD4+IFN-γ+cells)/Th2(CD4+IL-4+cells) balance, reduced CD4+IL-17+ and increased CD4+IL-10+ and CD4+TGF-β+ cells. The MFI of IL-10 and TGF-β in CD4+CD25+CD127- T cells were higher, whereas lower levels of IL-17 were observed. Bioinformatic analysis revealed that the TGF-β, Wnt signalling pathways and STAT5 transcription factor might mechanistically support the immunomodulatory effect of MSC-EVs. This study presents the immunomodulatory effect of MSC-EVs in PBMCs from AR patients. The results provide a new therapeutic strategy for AR.

Combination of proviral and antiviral roles of B cell-intrinsic STAT1 expression defines parameters of chronic gammaherpesvirus infection.

Gammaherpesviruses are species-specific, ubiquitous pathogens that establish lifelong infection in their hosts and are associated with cancers, including B cell lymphomas. Type I and II interferons (IFNs) are critical for the control of acute and chronic gammaherpesvirus infection. However, the cell type-specific role of IFN signaling during natural infection is poorly defined and is masked by the altered viral pathogenesis observed in hosts with global IFN deficiencies. STAT1 is a constitutively expressed transcription factor that is critical for the effector function of type I and II IFNs. In this study, we defined the impact of B cell-specific STAT1 expression on gammaherpesvirus infection using murine gammaherpesvirus 68 (MHV68). While the acute stage of MHV68 infection was not affected, we found opposite, anatomic site-dependent effects of B cell-intrinsic STAT1 expression during chronic infection. Consistent with the antiviral role of STAT1, B cell-specific STAT1 expression attenuated the latent viral reservoir in peritoneal B cells of chronically infected mice. In contrast, STAT1 expression in splenic B cells supported the establishment of the latent MHV68 reservoir in germinal center B cells, revealing an unexpected proviral role of B cell-intrinsic STAT1 expression during chronic gammaherpesvirus infection. These STAT1-dependent MHV68 chronic infection phenotypes were fully recapitulated in the peritoneal cavity but not the spleen of mice with B cell-specific deficiency of type I IFN receptor. In summary, our study uncovers the intriguing combination of proviral and antiviral roles of B cell-intrinsic STAT1 expression during chronic gammaherpesvirus infection.IMPORTANCEInterferons (IFNs) execute broadly antiviral roles during acute and chronic viral infections. The constitutively expressed transcription factor STAT1 is a critical downstream effector of IFN signaling. Our studies demonstrate that B cell-intrinsic STAT1 expression has opposing and anatomic site-dependent roles during chronic gammaherpesvirus infection. Specifically, B cell-intrinsic STAT1 expression restricted gammaherpesvirus latent reservoir in the peritoneal cavity, consistent with the classical antiviral role of STAT1. In contrast, decreased STAT1 expression in splenic B cells led to the attenuated establishment of gammaherpesvirus latency and decreased latent infection of germinal center B cells, highlighting a novel proviral role of B cell-intrinsic STAT1 expression during chronic infection with a B cell-tropic gammaherpesvirus. Interestingly, B cell-specific type I IFN receptor deficiency primarily recapitulated the antiviral role of B cell-intrinsic STAT1 expression, suggesting the compensatory function of B cell-intrinsic type II IFN signaling or an IFN-independent proviral role of B cell-intrinsic STAT1 expression during chronic gammaherpesvirus infection.

MALAT1/miR-582-5p/GALNT1/MUC1 axis modulates progression of AML leukemia stem cells by regulating JAK2/STAT3 pathway.

Acute myeloid leukemia (AML) is characterized by uncontrolled clonal expansion and differentiation block of immature myeloid cells. Some studies have shown that leukemia stem cells (LSC) are thought to be responsible for the initiation and development of leukemia. Moreover, abnormal O-glycosylation is a key modification in the process of cancer malignancy. In this study, GALNT1 expression was significantly upregulated in LSCs, while knockdown of GALNT1 inhibited cell viability and promoted apoptosis. Importantly, GALNT1 was the direct target of miR-582-5P, and MALAT1 directly interacted with miR-582-5P. In addition, Our investigation corroborated that MALAT1 functioned as an endogenous sponge of miR-582-5P to regulate mucin1 (MUC1) expression, catalyzed by GALNT1, which modulated the activity of JAK2/STAT3 pathway. MALAT1 and MUC1 were targets of transcription factor STAT3 and were regulated by STAT3. In general, these new findings indicated that MALAT1/miR-582-5P/GALNT1 axis is involved in the progression of LSCs, illuminating the possible mechanism mediated by O-glycosylated MUC1 via JAK2/STAT3 pathway.

Eugenol restrains Angiotensin II-induced death, inflammation and ferroptosis of vascular smooth muscle cells by targeting STAT3/HMGB2 axis.

Eugenol has been found to inhibit a variety of disease processes, including abdominal aortic aneurysm (AAA) formation. However, the specific role and the underlying molecular mechanism of Eugenol in AAA progression need to be further revealed. Vascular smooth muscle cells (VSMCs) were pre-treated with Eugenol, followed by treated with Angiotensin II (Ang-II). VSMCs were transfected with HMGB2 siRNA or overexpression vector and treated with Ang-II to confirm the effect of HMGB2 on AAA progression. Cell proliferation and death were determined using cell counting kit 8 (CCK8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and flow cytometry. Inflammatory factors were examined by ELISA. Fe2+, glutathione (GSH) and malondialdehyde (MDA) levels were tested to evaluate cell ferroptosis. The protein levels of ferroptosis-related markers, high mobility group box 2 (HMGB2) and STAT3 were measured using western blot. Human AAA tissues and normal abdominal aortic tissues were collected to detect HMGB2 mRNA expression by quantitative real-time PCR. The interaction between HMGB2 and STAT3 was confirmed by chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter assay. Eugenol enhanced VSMCs proliferation, while restrained Ang-II-induced death, inflammation and ferroptosis. HMGB2 was upregulated in AAA tissues and Ang-II-induced VSMCs, and Eugenol significantly decreased HMGB2 expression. HMGB2 knockdown reduced Ang-II-induced VSMCs death, inflammation and ferroptosis, Besides, HMGB2 overexpression abolished the effect of Eugenol on Ang-II-induced VSMCs injury. Transcription factor STAT3 bound to HMGB2 promoter region to increase its expression. In addition, Eugenol decreased STAT3 expression to regulate HMGB2. Eugenol could slow down the development of AAA, which might be achieved by regulating STAT3/HMGB2 axis.

The aryl hydrocarbon receptor shapes monocyte transcriptional responses to interleukin-4 by prolonging STAT6 binding to promoters.

Cytokines induce functional and metabolic adaptations in immune cells, typically through transcriptional responses that can be influenced by other extracellular signals and by intracellular factors. The binding of the cytokine interleukin-4 (IL-4) to its receptor induces the phosphorylation and activation of the transcription factor STAT6. The aryl hydrocarbon receptor (AhR), a transcription factor activated by various endogenous and microbe-derived metabolites, modulates the responses of immune cells to danger signals or inflammatory mediators such as cytokines. Here, we investigated cross-talk between the AhR and signaling stimulated by IL-4 in human and mouse monocytes. AhR activation was required for a subset of IL-4-induced transcriptional responses and inhibited the IL-4-induced metabolic switch to fatty acid β-oxidation. The promoters of the genes that were induced by IL-4 in an AhR-dependent manner lacked canonical AhR binding sites, implying a nongenomic mechanism of AhR action. Mechanistically, AhR activation reduced the activity of SHP-1, a phosphatase that targets and inhibits STAT6, and prolonged STAT6 phosphorylation and binding to specific target loci, thus extending the duration of STAT6 activity. Our results identify AhR as a key player in the molecular control of responses to IL-4 in monocytes and suggest a nongenomic mechanism through which AhR ligands may influence the functional responses of cells to IL-4.

Interleukin-1 Receptor-Associated Kinase 1 in Cancer Metastasis and Therapeutic Resistance: Mechanistic Insights and Translational Advances.

Interleukin-1 Receptor Associated Kinase 1 (IRAK1) is a serine/threonine kinase that plays a critical role as a signaling transducer of the activated Toll-like receptor (TLR)/Interleukin-1 receptor (IL-1R) signaling pathway in both immune cells and cancer cells. Upon hyperphosphorylation by IRAK4, IRAK1 forms a complex with TRAF6, which results in the eventual activation of the NF-κB and MAPK pathways. IRAK1 can translocate to the nucleus where it phosphorylates STAT3 transcription factor, leading to enhanced IL-10 gene expression. In immune cells, activated IRAK1 coordinates innate immunity against pathogens and mediates inflammatory responses. In cancer cells, IRAK1 is frequently activated, and the activation is linked to the progression and therapeutic resistance of various types of cancers. Consequently, IRAK1 is considered a promising cancer drug target and IRAK1 inhibitors have been developed and evaluated preclinically and clinically. This is a comprehensive review that summarizes the roles of IRAK1 in regulating metastasis-related signaling pathways of importance to cancer cell proliferation, cancer stem cells, and dissemination. This review also covers the significance of IRAK1 in mediating cancer resistance to therapy and the underlying molecular mechanisms, including the evasion of apoptosis and maintenance of an inflammatory tumor microenvironment. Finally, we provide timely updates on the development of IRAK1-targeted therapy for human cancers.

GPR30 Agonist G1 Mitigates Sepsis-Induced Cardiac Dysfunction by Inhibiting ACE2/c-FOS-Mediated Necroptosis in Female Mice.

Sepsis is a severe inflammatory syndrome with high mortality and morbidity. Sepsis-induced myocardial dysfunction (SIMD) is a common cause of death in sepsis. The female sex is less susceptible to sepsis-related organ dysfunction, although the underlying mechanism of this sex difference remains unclear. This study explored the role of estrogen receptor G protein-coupled estrogen receptor 30 (GPR30) in septic cardiac dysfunction. Results from the present study indicated that GPR30 activation by the G1 agonist protected female mouse hearts against SIMD exposed to lipopolysaccharides. However, this beneficial effect was absent in female ACE2-knockout mice, as demonstrated by poorer cardiac contractility, myocardial injury, and necroptosis. We also demonstrated that the Stat6 transcription factor induced ace2 transcription by enhancing its promoter activity under GPR30 activation in septic hearts. The adenovirus-mediated inhibition of ACE2 targeting c-FOS expression reversed the deterioration, restored cardiac function, and improved survival in female ACE2-knockout mice. These results demonstrate the essential role of GPR30/STAT6/ACE2/c-FOS-mediated necroptosis in G1-mediated protection and provide novel insight into the pathogenesis of sepsis-related organ damage.

MARCH8 Mediates K27-Linked Polyubiquitination of IL-7 Receptor α to Negatively Regulate IL-7-Triggered T Cell Homeostasis.

IL-7 is a cytokine produced by stromal cells, which binds to IL-7Rα and plays an important role for homeostasis of T lymphocytes. Excessive activities of IL-7-triggered signaling pathways causes autoimmune diseases. How IL-7-triggered signaling and immune effects are regulated is not fully understood. In this study, we show that the membrane-associated RING-CH (MARCH) E3 ligase family member MARCH8 mediates K27-linked polyubiquitination of IL-7Rα, leading to its lysosomal degradation. Site-directed mutagenesis suggests that MARCH8 meditates polyubiquitination of IL-7Rα at K265/K266, and mutation of these residues renders IL-7Rα resistance to MARCH8-mediated polyubiquitination and degradation. MARCH8 deficiency increases IL-7-triggered activation of the downstream transcription factor STAT5 and transcriptional induction of the effector genes in human T lymphoma cells. MARCH8 deficiency also promotes IL-7-triggered T cell proliferation and splenic memory CD8+ T cell differentiation in mice. Our findings suggest that MARCH8 negatively regulates IL-7-triggered signaling by mediating K27-linked polyubiquitination and lysosomal degradation of IL-7Rα, which reveals a negative regulatory mechanism of IL-7-triggered T cell homeostasis.

GRB7-mediated enhancement of cell malignant characteristics induced by Helicobacter pylori infection.

Growth factor receptor bound protein 7 (GRB7) is reportedly upregulated in human gastric cancer (GC), which is closely associated with tumor progression and prognosis. However, the mechanism underlying its dysregulation in GC remains poorly understood. In this study, we found that GRB7 overexpression was associated with Helicobacter pylori (H. pylori) infection. GC cells (AGS and MGC-803) infection assays revealed that this upregulation was mediated by the transcription factor STAT3, and activation of STAT3 by H. pylori promoted GRB7 expression in infected GC cells. Moreover, CagA, the key virulence factor of H. pylori, was found involved in STAT3-mediated GRB7 overexpression. The overexpressed GRB7 further promoted GC cell proliferation, migration, and invasion by activating ERK signaling. Mice infection was further used to investigate the action of GRB7. In H. pylori infection, GRB7 expression in mice gastric mucosa was elevated, and higher STAT3 and ERK activation were also detected. These results revealed GRB7-mediated pathogenesis in H. pylori infection, in which H. pylori activates STAT3, leading to increased GRB7 expression, then promotes activation of the ERK signal, and finally enhances malignant properties of infected cells. Our findings elucidate the role of GRB7 in H. pylori-induced gastric disorders, offering new prospects for the treatment and prevention of H. pylori-associated gastric carcinogenesis by targeting GRB7.

Targeted V-type peptide-decorated nanoparticles prevent colitis by inhibiting endosomal TLR signaling and modulating intestinal macrophage polarization

Inflammatory bowel disease (IBD) has become a serious and challenging health problem globally without curative medical treatments. Mounting evidence suggests that intestinal macrophages and their phenotypes are key players in the pathogenesis of IBD. Modulating the phenotypes and functions of intestinal macrophages through targeted interventions could be a promising approach to manage detrimental gut inflammation in IBD. In this study, we rationally design and fabricate a novel class of V-type peptide-decorated nanoparticles, VP-NP, with potent anti-inflammatory activity. Such a design allows two functional motifs FFD in a single peptide molecule to enhance the bioactivity of the nanoparticles. As expected, VP-NP exhibits a strong inhibitory activity on endosomal Toll-like receptor (TLR) signaling. Surprisingly, VP-NP can inhibit M1 polarization while facilitating M2 polarization in mouse bone marrow-derived macrophages through regulating the key transcription factors NF-κB, STAT1 and PPAR-γ. Mechanistically, VP-NP is internalized by macrophages in the endosomes, where it blocks endosomal acidification to inhibit endosomal TLR signaling; the transcriptomic analysis reveals that VP-NP potently down-regulates many genes in TLR, NF-κB, JAK-STAT, and cytokine/chemokine signaling pathways associated with inflammatory responses. In a colitis mouse model, the intraperitoneally administered VP-NP effectively alleviates the disease activities by decreasing colon inflammation and injuries, pro-inflammatory cytokine production, and myeloid cell infiltration in the gut. Furthermore, VP-NP primarily targets intestinal macrophages and alters their phenotypes from inflammatory M1-type toward the anti-inflammatory M2-type. This study provides a new nanotherapeutic strategy to specifically regulate macrophage activation and phenotypes through a dual mechanism to control gut inflammation, which may augment current clinical treatments for IBD.

Improvement of Docetaxel Efficacy through Simultaneous Blockade of Transcription Factors NF-κB and STAT-3 Using Pentoxifylline and Stattic in Prostate Cancer Cells.

Prostate cancer (PCa) is a common and deadly disease in men. It is often diagnosed at advanced stages, at which point patients are treated mainly with docetaxel (DTX), which is effective but limited by resistance and side effects. Overactivation of the transcription factors NF-κB and STAT-3 plays a critical role in the development, progression, and chemoresistance of PCa. In this regard, the blockade of NF-κB with pentoxifylline (PTX) or STAT-3 with Stattic (STT) is known to increase the sensitivity of tumor cells to chemotherapy in both in vitro and in vivo models. We investigated whether simultaneous blockade with PTX and STT increases the efficacy of the DTX treatment in inducing apoptosis in metastatic castration-resistant PCa DU-145 cells. Our results showed that the combination of PTX + STT led to higher levels of apoptosis, regardless of whether or not DTX was present in the treatment. Determining caspases and ΔΨm indicates that the intrinsic caspase pathway of apoptosis is principally favored. In addition, this combination inhibited proliferation and colony formation and arrested the cell cycle in the G1 phase. These results indicate that the combination of the PTX + STAT-3 inhibitor could potentiate DTX effectively, opening the possibility of effective treatments in PCa.

Long non-coding RNA SUN2-AS1 acts as a negative regulator of ISGs transcription to promote flavivirus infection

Recent studies highlight the critical involvement of long non-coding RNAs (lncRNAs) in modulating viral replication and immune responses, yet their specific roles in flavivirus infections remain underexplored. Our study has identified lncRNA SUN2-AS1, which is significantly upregulated in response to flavivirus infection in A549, Huh7 cells, and monocyte-differentiated macrophages (MDMs). SUN2-AS1 interacts with the transcription factors NF-κB and STAT1, andits expression is induced by ZIKV RNA via the type I interferon (IFN) pathway. Notably, SUN2-AS1 enhances the infection of flaviviruses, including ZIKV, DENV2, and JEV, while showing no effect on VSV or HSV-1 infections. Mechanistically, SUN2-AS1 exerts a proviral effect by inhibiting the transcription of interferon-stimulated genes (ISGs). These findings uncover a novel mechanism by which lncRNAs facilitate flavivirus propagation and highlight SUN2-AS1 as a potential target for antiviral therapeutic strategies.

The pro-inflammatory cytokines IL-1β and IL-6 promote upregulation of the ST6GAL1 sialyltransferase in pancreatic cancer cells

The ST6GAL1 sialyltransferase is overexpressed in multiple cancers including pancreatic ductal adenocarcinoma (PDAC). ST6GAL1 adds an α2-6-linked sialic acid to N-glycosylated membrane receptors, which consequently modulates receptor structure and function. While many studies have investigated the effects of ST6GAL1 on cell phenotype, there is a dearth of knowledge regarding mechanisms that regulate ST6GAL1 expression. In the current study, we evaluated the regulation of ST6GAL1 by two pro-inflammatory cytokines, IL-1β and IL-6, that are abundant within the PDAC tumor microenvironment. Cytokine activity was monitored using the Suit-2 PDAC cell line and two Suit-2-derived metastatic subclones, S2-013 and S2-LM7AA. For all three cell models, treatment with IL-1β or IL-6 increased the expression of ST6GAL1 protein and mRNA. Specifically, IL-1β and IL-6 induced expression of the ST6GAL1 YZ mRNA isoform, which is driven by the P3 promoter. The ST6GAL1 H and X isoforms were not detected. Promoter reporter assays confirmed that IL-1β and IL-6 activated transcription from the P3 promoter. We then examined downstream signaling mechanisms. IL-1β is known to signal through the NFκB transcription factor, whereas IL-6 signals through the STAT3 transcription factor. CUT&RUN experiments revealed that IL-1β promoted the binding of NFκB to the ST6GAL1 P3 promoter, and IL-6 induced the binding of STAT3 to the P3 promoter. Finally, we determined that inhibitors of NFκB and STAT3 blocked the upregulation of ST6GAL1 stimulated by IL-1β and IL-6, respectively. Together, these results highlight a novel molecular pathway by which cytokines within the tumor microenvironment stimulate the upregulation of ST6GAL1 in PDAC cells.

Effect of capsaicin on monocyte differentiation in patients with chronic obstructive pulmonary disease

Introduction. It is known that monocytes and derived macrophages play an important role in the development of chronic obstructive pulmonary disease (COPD). Previously, we found that cigarette smoke-sensitive TRPV1 channels have higher expression on monocytes and macrophages of COPD patients.Aim. To investigate the effect of chronic TRPV1 activation on the differentiation of monocytes into macrophages in vitro.Materials and methods. The study included 11 patients with COPD and 7 healthy non-smoking volunteers (control). Monocytes were obtained from peripheral blood mononuclear cells by plastic adhesion. Cells were cultured for 10 days in the presence of granulocytemacrophage colony-stimulating factor (GM-CSF) or GM-CSF and the TRPV1 agonist capsaicin. On the 11th day, the cells were stimulated with lipopolysaccharides (LPS). Expression of the genes encoding the transcription factors STAT1, STAT6, IRF3, JUN, MAF, RELA, cytokines IL1B, IL6, IL8, and three reference genes B2M, RACK1 and HPRT1 was assessed by quantitative PCR with reverse transcription.Results. Initially, macrophages of COPD patients differentiated in the presence of GM-CSF had higher expression of STAT1 (2.98-fold, p=0.03) and JUN (1.6-fold, p=0.02). LPS stimulation was accompanied by upregulation of IRF3 (4.3-fold, p=0.04), RELA (1.3-fold, p=0.05) and interleukin genes. Under the action of LPS COPD macrophages had 3.2-fold higher expression of IRF3 as compared to the control (p=0.05). Capsaicin also caused upregulation of IRF3 in cells from COPD patients, thus the expression of this factor became 3.2-fold higher than in the control group (p=0.03). Differentiation with capsaicin sensitized macrophages to LPS. Under these conditions JUN expression increased both in COPD patients (1.8-fold, p=0.01) and in the control group (2.2-fold, p=0.02) as compared with cells differentiated with GM-CSF alone.Conclusion. The obtained results indicate that in resting state macrophages from COPD patients are mostly characterized by a proinflammatory M1 polarization. LPS probably leads to an additional polarization towards M2b phenotype, when compared with the control, as indicated by an increase in the level of IRF3 transcripts. Capsaicin also promotes M2b polarization of COPD macrophages and may enhance the inflammatory response of cells to LPS.

High extracellular matrix stiffness promotes the metastasis of nasopharyngeal carcinoma through STAT3/FGF1 positive feedback regulation activated by JAK2

The stiffness of the extracellular matrix (EM) is known to be associated with tumor metastasis. This study aims to clarify the function and mechanisms of EM stiffness in nasopharyngeal carcinoma (NPC) and to provide a potential therapeutic target for patients with NPC. The NPC cell lines were cultured under varying stiffnesses. Plate cloning, Transwell assays and scratch tests were conducted to compare the phenotypes. Transcriptome sequencing and enrichment analysis were performed to explore the key molecules and the downstream signaling pathways, which were verified via in vitro and in vivo experiments. Our study showed that the NPC cells cultured on a stiff substrate (50 ​kPa) had greater colony formation, invasion and migration abilities than those cultured on a soft substrate. Transcriptome sequencing showed that a stiff environment induced high expression of fibroblast growth factor 1 (FGF1), which suggested a poor prognosis in various malignancies. The phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway played an important role in NPC metastasis activated by the FGF1 autocrine pathway in a stiff environment. The increased FGF1 expression was regulated by the transcription factor STAT3, and a positive feedback regulation between them was observed. The use of the JAK inhibitor Ruxolitinib and JAK2 interference inhibited the activation of STAT3. In conclusion, JAK2 activates STAT3/FGF1 positive feedback regulation and promotes NPC metastasis via the PI3K/Akt signaling pathway in a high-stiffness environment. Hence, FGF1 can be used as a potential therapeutic target for patients with NPC.

AKR1C1 interacts with STAT3 to increase intracellular glutathione and confers resistance to oxaliplatin in colorectal cancer

Oxaliplatin (OXA), a platinum-based chemotherapeutic agent, remains a mainstay in first-line treatments for advanced colorectal cancer (CRC). However, the eventual development of OXA resistance represents a significant clinical challenge. In the present study, we demonstrate that the aldo-keto reductase 1C1 (AKR1C1) is overexpressed in CRC cells upon acquisition of OXA resistance, evident in OXA-resistant CRC cell lines. We employed genetic silencing and pharmacological inhibition strategies to establish that suppression of AKR1C1 restores OXA sensitivity. Mechanistically, AKR1C1 interacts with and activates the transcription factor STAT3, which upregulates the glutamate transporter EAAT3, thereby elevating intracellular glutathione levels and conferring OXA resistance. Alantolactone, a potent natural product inhibitor of AKR1C1, effectively reverses this chemoresistance, restricting the growth of OXA-resistant CRC cells both in vitro and in vivo. Our findings uncover a critical AKR1C1-dependent mechanism behind OXA resistance and propose a promising combinatorial therapeutic strategy to overcome this resistance in CRC.

Inhibiting the Otub1/phosphorylated STAT3 axis for the treatment of non-small cell lung cancer.

The transcription factor STAT3 is a promising target for the treatment of non-small cell lung cancer (NSCLC). STAT3 activity is mainly dependent on phosphorylation at tyrosine 705 (pSTAT3-Y705), but the modulation on pSTAT3-Y705 is elusive. By screening a library of deubiquitinases (Dubs), we found that the Otub1 increasesSTAT3 transcriptional activity. As a Dub, Otub1 binds to pSTAT3-Y705 and specifically abolishes its K48-linked ubiquitination, therefore preventing its degradation and promoting NSCLC cell survival. The Otub1/pSTAT3-Y705 axis could be a potential target for the treatment of NSCLC. To explore this concept, we screen libraries of FDA-approved drugs and natural products based on STAT3-recognition element-driven luciferase assay, from which crizotinib is found to block pSTAT3-Y705 deubiquitination and promotes its degradation. Different from its known action to induce ALK positive NSCLC cell apoptosis, crizotinib suppresses ALK-intact NSCLC cell proliferation and colony formation but not apoptosis. Furthermore, crizotinib also suppresses NSCLC xenograft growth in mice. Taken together, these findings identify Otub1 as the first deubiquitinase of pSTAT3-Y705 and provide that the Otub1/pSTAT3-Y705 axis is a promising target for the treatment of NSCLC.

Characteristics of the Dynamic Evolutionary Pathway of ADSCs Induced Differentiation into Astrocytes Based on scRNA-Seq Analysis.

We employed single-cell transcriptome sequencing to reveal the dynamic gene expression changes during the differentiation of adipose-derived stromal cells (ADSCs) into astrocytes. Single-cell RNA sequencing was conducted on cells from the ADSCs group and the induced groups at 2, 7, 14, and 21days using the 10 × Chromium platform. Data underwent quality control and dimensionality reduction. Cell differentiation trajectories were constructed using Monocle2, and differentially expressed genes (DEGs) in each cell cluster were identified using differential selection algorithms. DEGs at each time point were annotated using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and regulatory intensities of transcription factors were analyzed using SCENIC. Integrating all groups, a total of five samples were divided into 13 cell clusters (0-12 clusters). DEGs between clusters and those compared with ADSCs at various induced time points showed distinct specificities. Monocle2 constructed cell differentiation trajectories; ADSCs can differentiate into mature astrocytes not only through the direct pathway from the 1 branch to the 3 branch but also through an indirect pathway, involving the 1 branch to the 2 branch before progressing to the 3 branch. SCENIC analysis highlighted the critical regulatory roles of STAT1, MYEF2, and SOX6 transcription factors during the differentiation of ADSCs into astrocytes. ADSCs can differentiate into mature astrocytes through two distinct pathways: direct and indirect. By the 14th day of induction, mature astrocytes have formed, characterized by a cell cycle arrest in mitosis. Further induction leads to degenerative senescence changes in differentiated cells.

Anti-tumor effects of the eIF4A inhibitor didesmethylrocaglamide and its derivatives in human and canine osteosarcomas

Inhibition of translation initiation using eIF4A inhibitors like (−)-didesmethylrocaglamide [(−)-DDR] and (−)-rocaglamide [(−)-Roc] is a potential cancer treatment strategy as they simultaneously diminish multiple oncogenic drivers. We showed that human and dog osteosarcoma cells expressed higher levels of eIF4A1/2 compared with mesenchymal stem cells. Genetic depletion of eIF4A1 and/or 2 slowed osteosarcoma cell growth. To advance preclinical development of eIF4A inhibitors, we demonstrated the importance of (−)-chirality in DDR for growth-inhibitory activity. Bromination of DDR at carbon-5 abolished growth-inhibitory activity, while acetylating DDR at carbon-1 was tolerated. Like (−)-DDR, (±)-DDR, and (−)-Roc, (±)-DDR-acetate increased γH2A.X levels and induced G2/M arrest and apoptosis. Consistent with translation inhibition, these rocaglates decreased the levels of several mitogenic kinases, the STAT3 transcription factor, and the stress-activated protein kinase p38. However, phosphorylated p38 was greatly enhanced in treated cells, suggesting activation of stress response pathways. RNA sequencing identified RHOB as a top upregulated gene in both (−)-DDR- and (−)-Roc-treated osteosarcoma cells, but the Rho inhibitor Rhosin did not enhance the growth-inhibitory activity of (−)-DDR or (−)-Roc. Nonetheless, these rocaglates potently suppressed tumor growth in a canine osteosarcoma patient-derived xenograft model. These results suggest that these eIF4A inhibitors can be leveraged to treat both human and dog osteosarcomas.