The roles of STAT6 in regulating B cell fate, activation, and function

Targeting inflammation in cancer therapy: from mechanistic insights to emerging therapeutic approaches

Inflammation is a complex and finely tuned component of the host defense mechanism, responding sensitively to a range of physical, chemical, and biological stressors. Current research is advancing our grasp of both cellular and molecular mechanisms that initiate and regulate interactions within inflammatory pathways. Substantial evidence now indicates a profound link between inflammation, innate immunity, and cancer. Dysregulation of inflammatory pathways is known to be a pivotal factor in the induction, growth, and metastasis of tumors through multiple mechanistic pathways. Basically, the tumor microenvironment (TME), characterized by dynamic interplay between cancerous cells and surrounding inflammatory and stromal cells, plays a central role in these processes. Increasingly, controlled acute inflammation is being explored as a promising therapeutic tool in certain types of cancer. However, inflammatory cells in the TME exhibit remarkable plasticity, with shifting phenotypic and functional roles that facilitate cancer cell survival, proliferation, and migration, especially under chronic inflammatory conditions. Additionally, signaling molecules associated with the innate immune system, like chemokines, are co-opted by malignant cells to support invasion, migration, and metastasis. These findings underscore the need for deeper insights into the mechanisms connecting inflammation to cancer pathology, which could pave the way for innovative diagnostic approaches and targeted anti-inflammatory therapies to counter tumor development. The current review underlines the critical involvement of inflammation in cancer development, examining the connection between the immune system, key inflammatory mediators, biomarkers, and their associated pathways in cancer. We also discuss the impact of inflammation-targeted therapies on anticancer signaling pathways. Furthermore, we review major anti-inflammatory drugs with potential applications in oncology, assessing how inflammation is modulated in cancer management. Lastly, we outline an overview of ongoing discoveries in the field, highlighting both the challenges and the therapeutic promise of targeting inflammation in cancer therapy.

Temperature as a Key Modulator: Investigating Phosphorylation Patterns of p.Asn666 PDGFRB Variants and Their Role in Downstream Signaling

Four different amino acid substitutions have been reported at the p.Asn666 position in platelet-derived growth factor receptor β (PDGFRβ): p.Asn666Lys, p.Asn666Tyr, p.Asn666Ser, and p.Asn666His. All four substitutions result in strikingly different phenotypes, ranging from somatic infantile myofibromatosis in p.Asn666Lys and ocular pterygium-digital keloid dysplasia in p.Asn666Tyr to a severe form of Penttinen syndrome in p.Asn666Ser, while p.Asn666His is associated with a complex phenotype characterized by debilitating hand and foot contractures and facial coarseness. Here, we show that the p.Asn666Lys, p.Asn666Tyr, and p.Asn666His substitutions result in increased total PDGFRβ phosphorylation at 32°C compared to 37°C. All four substitutions exhibit distinct activation patterns of specific PDGFRβ tyrosine residues at both temperatures, indicating a unique activation of each variant. The temperature effect on downstream signaling is present across all substitutions, resulting in substitution-specific downstream signaling at both 37°C and 32°C. This complex interplay of downstream signaling proteins could be important for the clinical manifestations of p.Asn666 PDGFRB variants. Furthermore, variant-specific overactivation of tyrosine residues and downstream signaling at 32°C emphasize the importance of temperature as an environmental factor in the pathogenesis of this diverse group of disorders.

Estrogen influences class-switched memory B cell frequency only in humans with two X chromosomes

Sex differences in immunity are well-documented, though mechanisms underpinning these differences remain ill-defined. Here, in a human-only ex vivo study, we demonstrate that postpubertal cisgender females have higher levels of CD19+CD27+IgD- class-switched memory B cells compared with age-matched cisgender males. This increase is only observed after puberty and before menopause, suggesting a strong influence for sex hormones. Accordingly, B cells express high levels of estrogen receptor 2 (ESR2), and class-switch-regulating genes are enriched for ESR2-binding sites. In a gender-diverse cohort, blockade of natal estrogen in transgender males (XX karyotype) reduced class-switched memory B cell frequency, while gender-affirming estradiol treatment in transgender females (XY karyotype) did not increase these levels. In postmenopausal cis-females, class-switched memory B cells were increased in those taking hormone replacement therapy (HRT) compared with those who were not. These data demonstrate that sex hormones and chromosomes work in tandem to impact immune responses, with estrogen only influencing the frequency of class-switched memory B cells in individuals with an XX chromosomal background.

Combined autologous hematopoietic stem cell transplantation and CD19 CAR T-cell therapy for relapsed/refractory diffuse large B-cell lymphoma with TP53 mutation: A case report

Despite advancements in the treatment of diffuse large B-cell lymphoma, including CAR T-cell therapy, TP53 mutations remain a significant negative prognostic factor in patients with relapsed/refractory diffuse large B-cell lymphoma. The combination of autologous stem cell transplantation and CAR T-cell therapy may enhance long-term prognosis and reduce adverse effects, including severe cytokine release syndrome. This case report presents a 41-year-old man with relapsed/refractory diffuse large B-cell lymphoma harboring TP53 mutations who underwent autologous stem cell transplantation combined with CD19 CAR T-cell therapy. Two years posttreatment, the patient remains in sustained complete remission, highlighting the potential efficacy of this combination approach for relapsed/refractory diffuse large B-cell lymphoma with TP53 mutation.

Polymethoxylated flavone variations and in vitro biological activities of locally cultivated Citrus varieties in China

Citrus peels are rich in polymethoxylated flavones (PMFs), which have beneficial health and pharmacological properties. In this study, the profiles, variations, and biological activities of PMFs in the peel extracts of 27 Citrus varieties (eight species) native to China were investigated. UPLC-QTOF-MS/MS analysis revealed that mandarin accumulated more diversity and higher detectable PMF contents. Wangcangzhoupigan (ZPG) possessed the highest antioxidant capacity. Gailiangcheng (GLC) and Bingtangcheng (BTC), sweet oranges showed excellent inhibitory effects against pancreatic lipase and α-glucosidase, respectively. Most citrus extracts effectively inhibited the production of ROS and pro-inflammatory cytokines, while increasing the accumulation of anti-inflammatory cytokines. In addition, Limeng (LM), Cupig-oushigan (GSG), and Yanxiwanlu (YXWL) showed anti-proliferative effects against DU145 and PC3 cancer cells. This study provides a comprehensive PMF profile and biological activities of various citrus species and will benefit future functional citrus breeding practices aimed at designing plants rich in total or specific PMFs for health benefits.

Functional Involvement of Signal Transducers and Activators of Transcription in the Pathogenesis of Influenza A Virus

Signal transducers and activators of transcription (STATs) function both as signal transducers and transcription regulators. STAT proteins are involved in the signaling pathways of cytokines and growth factors; thus, they participate in various life activities and play especially critical roles in antiviral immunity. Convincing evidence suggests that STATs can establish innate immune status through multiple mechanisms, efficiently eliminating pathogens. STAT1 and STAT2 can activate the antiviral status by regulating the interferon (IFN) signal. In turn, suppressor of cytokine signaling-1 (SOCS1) and SOCS3 can modulate the activation of STATs and suppress the excessive antiviral immune response. STAT3 not only regulates the IFN signal, but also transduces Interleukin-6 (IL-6) to stimulate the host antiviral response. The function of STAT4 and STAT5 is related to CD4+ T helper (Th) cells, and the specific mechanism of STAT5 remains to be studied. STAT6 mainly exerts antiviral effects by mediating IL-4 and IL-13 signaling. Here, we reviewed the recent findings regarding the critical roles of STATs in the interactions between the host and viral infection, especially influenza A virus (IAV) infection. We also discuss the molecular mechanisms underlying their functions in antiviral responses.

The Role of the JAK-STAT Pathway in Childhood B-Cell Acute Lymphoblastic Leukemia

B-cell lymphoblastic leukemia is a hematologic neoplasm that poses a serious health concern in childhood. Genetic aberrations, such as mutations in the genes IL-7, IL7R, JAK1, JAK2, TLSP, CRLF2, and KTM2A or gene fusions involving BCR::ABL1, ETV6::RUNX1, and PAX5::JAK2, often correlate with the onset of this disease. These aberrations can lead to malfunction of the JAK-STAT signaling pathway, which is implicated in various important biological processes, including those related to immunology. Understanding the mechanisms underlying the malfunction of the JAK-STAT pathway holds potential for research on drugs targeting its components. Available drugs that interfere with the JAK-STAT pathway include fludarabine, ruxolitinib, and fedratinib.

Effects of conceptus proteins on endometrium and blood leukocytes of dairy cattle using transcriptome and meta-analysis

This study investigates the short and long-term effects of IFNT and PAG on the transcriptome of endometrium and blood leukocytes. Holstein heifers received intrauterine infusions of one of the following treatments: 20 mL of a 200 μg/mL bovine serum albumin solution (BSA; vehicle) from day 14 to 16 of the estrous cycle (BSA), vehicle + 10 μg/mL of IFNT from day 14 to 16 (IFNT3), vehicle + 10 μg/mL of IFNT from day 14 to 19 (IFNT6), and vehicle + 10 μg/mL of IFNT from day 14 to 16 followed by vehicle + 10 μg/mL of IFNT + 5 μg/mL of PAG from day 17 to 19 (IFNT+PAG). RNA-seq analysis was performed in endometrial biopsies and blood leukocytes collected after treatments. Acute IFNT signaling in the endometrium (IFNT3 vs BSA), induced differentially expressed genes (DEG) associated with interferon activation, immune response, inflammation, cell death, and inhibited vesicle transport and extracellular matrix remodeling. Prolonged IFNT signaling (IFNT6 vs IFNT3) altered gene expression related to cell invasion, retinoic acid signaling, and embryo implantation. In contrast, PAG induced numerous DEG in blood leukocytes but only 4 DEG in the endometrium. In blood leukocytes, PAG stimulated genes involved in development and TGFB signaling while inhibiting interferon signaling and cell migration. Overall, IFNT is a primary regulator of endometrial gene expression, while PAG predominantly affected the transcriptome of circulating immune cells during early pregnancy. Further research is essential to fully grasp the roles of identified DEG in both the endometrium and blood leukocytes.

Signal Transducer and Activator of Transcription Proteins at the Nexus of Immunodeficiency, Autoimmunity and Cancer

The signal transducer and activator of transcription (STAT) family of proteins has been demonstrated to perform pivotal roles downstream of a myriad of cytokines, particularly those that control immune cell production and function. This is highlighted by both gain-of-function (GOF) and loss-of-function (LOF) mutations being implicated in various diseases impacting cells of the immune system. These mutations are typically inherited, although somatic GOF mutations are commonly observed in certain immune cell malignancies. This review details the growing appreciation of STAT proteins as a key node linking immunodeficiency, autoimmunity and cancer.

Severe allergic dysregulation due to a gain of function mutation in the transcription factor STAT6

BACKGROUND

Inborn errors of immunity have been implicated in causing immune dysregulation, including allergic diseases. STAT6 is a key regulator of allergic responses.

OBJECTIVES

This study sought to characterize a novel gain-of-function STAT6 mutation identified in a child with severe allergic manifestations.

METHODS

Whole-exome and targeted gene sequencing, lymphocyte characterization, and molecular and functional analyses of mutated STAT6 were performed.

RESULTS

This study reports a child with a missense mutation in the DNA binding domain of STAT6 (c.1114G>A, p.E372K) who presented with severe atopic dermatitis, eosinophilia, and elevated IgE. Naive lymphocytes from the affected patient displayed increased TH2- and suppressed TH1- and TH17-cell responses. The mutation augmented both basal and cytokine-induced STAT6 phosphorylation without affecting dephosphorylation kinetics. Treatment with the Janus kinase 1/2 inhibitor ruxolitinib reversed STAT6 hyperresponsiveness to IL-4, normalized TH1 and TH17 cells, suppressed the eosinophilia, and improved the patient's atopic dermatitis.

CONCLUSIONS

This study identified a novel inborn error of immunity due to a STAT6 gain-of-function mutation that gave rise to severe allergic dysregulation. Janus kinase inhibitor therapy could represent an effective targeted treatment for this disorder.

Deficiencies and Dysregulation of STAT Pathways That Drive Inborn Errors of Immunity: Lessons from Patients and Mouse Models of Disease

The STAT family proteins provide critical signals for immune cell development, differentiation, and proinflammatory and anti-inflammatory responses. Inborn errors of immunity (IEIs) are caused by single gene defects leading to immune deficiency and/or dysregulation, and they have provided opportunities to identify genes important for regulating the human immune response. Studies of patients with IEIs due to altered STAT signaling, and mouse models of these diseases, have helped to shape current understanding of the mechanisms whereby STAT signaling and protein interactions regulate immunity. Although many STAT signaling pathways are shared, clinical and immune phenotypes in patients with monogenic defects of STAT signaling highlight both redundant and nonredundant pathways. In this review, we provide an overview of the shared and unique signaling pathways used by STATs, phenotypes of IEIs with altered STAT signaling, and recent discoveries that have provided insight into the human immune response and treatment of disease.

Jak2/STAT6/c-Myc pathway is vital to the pathogenicity of Philadelphia-positive acute lymphoblastic leukemia caused by P190BCR-ABL

BACKGROUND

The Philadelphia chromosome encodes the BCR-ABL fusion protein, which has two primary subtypes, P210 and P190. P210 and P190 cause Philadelphia-positive chronic myeloid leukemia (Ph+ CML) and Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL), respectively. The Ph+ ALL is more malignant than Ph+ CML in disease phenotype and progression. This implies the key pathogenic molecules and regulatory mechanisms caused by BCR-ABL in two types of leukemia are different. It is reported that STAT6 was significantly activated only in P190 transformed cells. However, the potential role and the mechanism of STAT6 activation in Ph+ ALL and its activation mechanism by P190 are still unknown.

METHODS

The protein and mRNA levels of STAT6, c-Myc, and other molecules were measured by western blot and quantitative real-time PCR. The STAT6 inhibitor AS1517499 was used to specifically inhibit p-STAT6. The effect of p-STAT6 inhibition on Ph+ CML and Ph+ ALL cells was identified by CCK-8 and FCM assay. Dual luciferase reporter and ChIP assay were performed to confirm the direct binding between STAT6 and c-Myc. The impact of STAT6 inhibition on tumor progression was detected in Ph+ CML and Ph+ ALL mouse models.

RESULTS

Our results demonstrated that P210 induced CML-like disease, and P190 caused the more malignant ALL-like disease in mouse models. STAT6 was activated in P190 cell lines but not in P210 cell lines. Inhibition of STAT6 suppressed the malignancy of Ph+ ALL in vitro and in vivo, whereas it had little effect on Ph+ CML. We confirmed that p-STAT6 regulated the transcription of c-Myc, and STAT6 was phosphorylated by p-Jak2 in P190 cell lines, which accounted for the discrepant expression of p-STAT6 in P190 and P210 cell lines. STAT6 inhibition synergized with imatinib in Ph+ ALL cells.

CONCLUSIONS

Our study suggests that STAT6 activation plays an essential role in the development of Ph+ ALL and may be a potential therapeutic target in Ph+ ALL. Video abstract.

The JAK-STAT Signaling Pathway in Epilepsy

Epilepsy is defined as spontaneous recurrent seizures in the brain. There is increasing evidence that inflammatory mediators and immune cells are involved in epileptic seizures. As more research is done on inflammatory factors and immune cells in epilepsy, new targets for the treatment of epilepsy will be revealed. The Janus kinase-signal transducer and transcriptional activator (JAKSTAT) signaling pathway is strongly associated with many immune and inflammatory diseases, At present, more and more studies have found that the JAK-STAT pathway is involved in the development and development of epilepsy, indicating the JAK-STAT pathway's potential promise as a target in epilepsy treatment. In this review, we discuss the composition, activation, and regulation of the JAK-STAT pathway and the relationship between the JAK-STAT pathway and epilepsy. In addition, we summarize the common clinical inhibitors of JAK and STAT that we would expect to be used in epilepsy treatment in the future.

Perspectives of herbs and their natural compounds, and herb formulas on treating diverse diseases through regulating complicated JAK/STAT signaling

JAK/STAT signaling pathways are closely associated with multiple biological processes involved in cell proliferation, apoptosis, inflammation, differentiation, immune response, and epigenetics. Abnormal activation of the STAT pathway can contribute to disease progressions under various conditions. Moreover, tofacitinib and baricitinib as the JAK/STAT inhibitors have been recently approved by the FDA for rheumatology disease treatment. Therefore, influences on the STAT signaling pathway have potential and perspective approaches for diverse diseases. Chinese herbs in traditional Chinese medicine (TCM), which are widespread throughout China, are the gold resources of China and have been extensively used for treating multiple diseases for thousands of years. However, Chinese herbs and herb formulas are characterized by complicated components, resulting in various targets and pathways in treating diseases, which limits their approval and applications. With the development of chemistry and pharmacology, active ingredients of TCM and herbs and underlying mechanisms have been further identified and confirmed by pharmacists and chemists, which improved, to some extent, awkward limitations, approval, and applications regarding TCM and herbs. In this review, we summarized various herbs, herb formulas, natural compounds, and phytochemicals isolated from herbs that have the potential for regulating multiple biological processes via modulation of the JAK/STAT signaling pathway based on the published work. Our study will provide support for revealing TCM, their active compounds that treat diseases, and the underlying mechanism, further improving the rapid spread of TCM to the world.

STAT proteins: a kaleidoscope of canonical and non-canonical functions in immunity and cancer

STAT proteins represent an important family of evolutionarily conserved transcription factors that play key roles in diverse biological processes, notably including blood and immune cell development and function. Classically, STAT proteins have been viewed as inducible activators of transcription that mediate cellular responses to extracellular signals, particularly cytokines. In this 'canonical' paradigm, latent STAT proteins become tyrosine phosphorylated following receptor activation, typically via downstream JAK proteins, facilitating their dimerization and translocation into the nucleus where they bind to specific sequences in the regulatory region of target genes to activate transcription. However, growing evidence has challenged this paradigm and identified alternate 'non-canonical' functions, such as transcriptional repression and roles outside the nucleus, with both phosphorylated and unphosphorylated STATs involved. This review provides a revised framework for understanding the diverse kaleidoscope of STAT protein functional modalities. It further discusses the implications of this framework for our understanding of STAT proteins in normal blood and immune cell biology and diseases such as cancer, and also provides an evolutionary context to place the origins of these alternative functional modalities.

Mid-gestation cytokine profiles in mothers of children affected by autism spectrum disorder: a case-control study

Autism Spectrum disorder is one of the commonest and most important neurodevelopmental conditions affecting children today. With an increasing prevalence and an unclear aetiology, it is imperative we find early markers of autism, which may facilitate early identification and intervention. Alterations of gestational cytokine profiles have been reported in mothers of autistic children. Increasing evidence suggests that the intrauterine environment is an important determinant of autism risk. This study aims to examine the mid-gestational serum cytokine profiles of the mothers of autistic children from a well-characterised birth cohort. A nested sub-cohort within a large mother-child birth cohort were identified based on a confirmed multi-disciplinary diagnosis of autism before the age 10 years and neuro-typical matched controls in a 2:1 ratio. IFN-γ, IL-1β, IL-4, IL-6, IL-8, IL-17A, GMCSF and TNFα were measured in archived maternal 20-week serum using MesoScale Diagnostics multiplex technology and validation of our IL-17A measurements was performed using an ultrasensitive assay. From a cohort of 2137 children, 25 had confirmed autism before 10 years and stored maternal serum from mid-gestation. We examined the sera of these 25 cases and 50 matched controls. The sex ratio was 4:1 males to females in each group, and the mean age at diagnosis was 5.09 years (SD 2.13). We found that concentrations of IL-4 were significantly altered between groups. The other analytes did not differ significantly using either multiplex or ultra-sensitive assays. In our well-characterised prospective cohort of autistic children, we confirmed mid-gestational alterations in maternal IL-4 concentrations in autism affected pregnancies versus matched controls. These findings add to promising evidence from animal models and retrospective screening programmes and adds to the knowledge in this field.

The Ups and Downs of STAT Inhibition in Acute Myeloid Leukemia

Aberrant Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling is implicated in the pathogenesis of acute myeloid leukemia (AML), a highly heterogeneous hematopoietic malignancy. The management of AML is complex and despite impressive efforts into better understanding its underlying molecular mechanisms, survival rates in the elderly have not shown a substantial improvement over the past decades. This is particularly due to the heterogeneity of AML and the need for personalized approaches. Due to the crucial role of the deregulated JAK-STAT signaling in AML, selective targeting of the JAK-STAT pathway, particularly constitutively activated STAT3 and STAT5 and their associated upstream JAKs, is of great interest. This strategy has shown promising results in vitro and in vivo with several compounds having reached clinical trials. Here, we summarize recent FDA approvals and current potential clinically relevant inhibitors for AML patients targeting JAK and STAT proteins. This review underlines the need for detailed cytogenetic analysis and additional assessment of JAK-STAT pathway activation. It highlights the ongoing development of new JAK-STAT inhibitors with better disease specificity, which opens up new avenues for improved disease management.

Bioinformatics Analysis of Expression Profiles and Prognostic Values of the Signal Transducer and Activator of Transcription Family Genes in Glioma

Signal transducer and activator of transcription (STAT) family genes—of which there are seven members: STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B, and STAT6—have been associated with the progression of multiple cancers. However, their prognostic values in glioma remain unclear. In this study, we systematically investigated the expression, the prognostic value, and the potential mechanism of the STAT family genes in glioma. The expression of STAT1/2/3/5A/6 members were significantly higher and positively correlated with IDH mutations, while the expression of STAT5B was lower and negatively correlated with IDH mutations in glioma. Survival analysis indicated that the upregulation of STAT1/2/3/5A/6 and downregulation of STAT5B expression was associated with poorer overall survival in glioma. Joint effects analysis of STAT1/2/3/5A/5B/6 expression suggested that the prognostic value of the group was more significant than that of each individual gene. Thus, we constructed a risk score model to predict the prognosis of glioma. The receiver operating characteristic curve and calibration curves showed good performance as prognostic indicators in both TCGA (The Cancer Genome Atlas) and the CGGA (Chinese Glioma Genome Atlas) databases. Furthermore, we analyzed the correlation between STAT expression with immune infiltration in glioma. The Protein–protein interaction network and enrichment analysis showed that STAT members and co-expressed genes mainly participated in signal transduction activity, Hepatitis B, the Jak-STAT signaling pathway, transcription factor activity, sequence-specific DNA binding, and the cytokine-mediated signaling pathway in glioma. In summary, our study analyzed the expression, prognostic values, and biological roles of the STAT gene family members in glioma, based on which we developed a new risk score model to predict the prognosis of glioma more precisely.