Stat6 activity-related Th2 cytokine profile and tumor growth advantage of human colorectal cancer cells in vitro and in vivo

JAM2 is a prognostic biomarker and inhibits proliferation, metastasis and epithelial-mesenchymal transition in lung adenocarcinoma

BACKGROUND

Junctional adhesion molecule 2 (JAM2) plays a pivotal role in various biological processes, including proliferation, metastasis and angiogenesis, contributing to tumor progression. While previous studies have highlighted the polarizing functions of JAM2 in different cancer types, its specific role in lung adenocarcinoma (LUAD) remains unclear.

METHODS

In this study, we harnessed multiple public databases to analyze the expression and prognostic significance of JAM2 in LUAD. Using the Linkedomics database, Matescape database and R package, we explored the associated genes, the potential biological functions and the impact of JAM2 on the tumor microenvironment. Our findings from public databases were further validated using real-time quantitative PCR, western blot and immunohistochemistry. Additionally, in vitro experiments were conducted to assess the influence of JAM2 on LUAD cell proliferation, invasion, migration, apoptosis and epithelial-mesenchymal transition. Furthermore, we established a xenograft model to investigate the in vivo effects of JAM2 on tumorigenesis.

RESULTS

Our results revealed a significant downregulation of JAM2 in LUAD, and patients with low JAM2 expression exhibited unfavorable overall survival outcomes. Functional enrichment analysis indicated that JAM2 may be associated with processes such as cell adhesion, extracellular matrix, cell junctions and regulation of proliferation. Notably, increased JAM2 expression correlated with higher tumor microenvironment scores and reduced immune cell abundance. Furthermore, overexpression of JAM2 induced apoptosis, suppressed tumor proliferation and exhibited potential inhibitory effects on tumor invasion and migration through the modulation of epithelial-mesenchymal transition. Additionally, in vivo experiments confirmed that JAM2 overexpression led to a reduction in tumor growth.

CONCLUSION

Overall, our study highlights the clinical significance of low JAM2 expression as a predictor of poor prognosis in LUAD patients. Moreover, JAM2 was found to exert inhibitory effects on various aspects of tumor progression. Consequently, JAM2 emerges as a promising prognostic biomarker and a potential therapeutic target for LUAD patients.

CD44 occurring alternative splicing promotes cisplatin resistance and evokes tumor immune response in oral squamous cell carcinoma cells

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most prevalent malignant tumor in head and neck region. Platinum drug resistance limits the clinical application of chemotherapy regardless of medical development. The aim of our study is to identify cisplatin-resistant genes which can be used as new therapeutic targets and investigate the functional mechanism of OSCC chemoresistance.

METHODS

The OSCC Cal27 and HSC4 cisplatin-resistant cell lines were constructed to screen the differential genes/transcripts expression. GO, KEGG and GSEA were performed to reveal the relevant signaling pathways. Alternative splicing (AS) software rMATs was applied to explore AS events in chemoresistance. R package and TIMER tools were used to evaluate the linear correlation between CD44 and immune cell subpopulations. The co-culture model of dendritic cells (DCs) and OSCC cells was applied to explore the effect of CD44 on immune microenvironment and cisplatin resistance.

RESULTS

Our results showed that CD44 was differentially expressed in cisplatin-resistant OSCC cells. Through bioinformatics prediction and experimental verification, we confirmed that CD44 occurring AS was involved in tumor progression and cisplatin resistance. Moreover, CD44 could further enhance the cisplatin resistance of OSCC by activating DCs, making CD44 to be a potential intervention target. We also identified DC as a new target for platinum drugs to stimulate the growth of OSCC.

CONCLUSION

Our findings not only make it possible to explore new therapeutic methods, such as CD44 inhibitors or antisense oligonucleotides, but also provide insights into the new mechanisms of cisplatin resistance to chemotherapy.

Distinct T helper cell-mediated antitumor immunity: T helper 2 cells in focus

The adaptive arm of the immune system is crucial for appropriate antitumor immune responses. It is generally accepted that clusters of differentiation 4+ (CD4+) T cells, which mediate T helper (Th) 1 immunity (type 1 immunity), are the primary Th cell subtype associated with tumor elimination. In this review, we discuss evidence showing that antitumor immunity and better prognosis can be associated with distinct Th cell subtypes in experimental mouse models and humans, with a focus on Th2 cells. The aim of this review is to provide an overview and understanding of the mechanisms associated with different tumor outcomes in the face of immune responses by focusing on the (1) site of tumor development, (2) tumor properties (i. e., tumor metabolism and cytokine receptor expression), and (3) type of immune response that the tumor initially escaped. Therefore, we discuss how low-tolerance organs, such as lungs and brains, might benefit from a less tissue-destructive immune response mediated by Th2 cells. In addition, Th2 cells antitumor effects can be independent of CD8+ T cells, which would circumvent some of the immune escape mechanisms that tumor cells possess, like low expression of major histocompatibility-I (MHC-I). Finally, this review aims to stimulate further studies on the role of Th2 cells in antitumor immunity and briefly discusses emerging treatment options.

CD44V3, an Alternatively Spliced Form of CD44, Promotes Pancreatic Cancer Progression

Pancreatic cancer is one of the most lethal malignant tumors. However, the molecular mechanisms responsible for its progression are little known. This study aimed to understand the regulatory role of CD44V3 in pancreatic cancer. A Kaplan–Meier analysis was performed to reveal the correlation between CD44/CD44V3 expression and the prognosis of pancreatic cancer patients. CD44V3 and U2AF1 were knocked down using shRNAs. The proliferation, migration, invasion, and stemness of two pancreatic cell lines, BxPC-3 and AsPC-1, were examined. The expression of CD44V3, cancer-associated markers, and the activation of AKT signaling were detected by qRT-PCR and Western blot. Both CD44 and CD44V3 expression levels were associated with a poor prognosis in pancreatic cancer patients. Interestingly, the expression of CD44V3, instead of CD44, was greatly increased in tumor tissues. CD44V3 knockdown inhibited the proliferation, migration, invasion, and stemness of cancer cells. CD44V3 splicing was regulated by U2AF1 and downregulation of U2AF1 enhanced CD44V3 expression, which promoted pancreatic cancer progression. CD44V3 is an important cancer-promoting factor, which may serve as a potential candidate for pancreatic cancer intervention.

The Role and Regulation of Thromboxane A2 Signaling in Cancer-Trojan Horses and Misdirection

Over the last two decades, there has been an increasing awareness of the role of eicosanoids in the development and progression of several types of cancer, including breast, prostate, lung, and colorectal cancers. Several processes involved in cancer development, such as cell growth, migration, and angiogenesis, are regulated by the arachidonic acid derivative thromboxane A₂ (TXA₂). Higher levels of circulating TXA₂ are observed in patients with multiple cancers, and this is accompanied by overexpression of TXA₂ synthase (TBXAS1, TXA₂S) and/or TXA₂ receptors (TBXA2R, TP). Overexpression of TXA₂S or TP in tumor cells is generally associated with poor prognosis, reduced survival, and metastatic disease. However, the role of TXA₂ signaling in the stroma during oncogenesis has been underappreciated. TXA₂ signaling regulates the tumor microenvironment by modulating angiogenic potential, tumor ECM stiffness, and host immune response. Moreover, the by-products of TXA₂S are highly mutagenic and oncogenic, adding to the overall phenotype where TXA₂ synthesis promotes tumor formation at various levels. The stability of synthetic enzymes and receptors in this pathway in most cancers (with few mutations reported) suggests that TXA₂ signaling is a viable target for adjunct therapy in various tumors to reduce immune evasion, primary tumor growth, and metastasis.

The roles of post-translational modifications and coactivators of STAT6 signaling in tumor growth and progression

Signal transducers and activators of transcription 6 (STAT6) are highly expressed in various tumors and associated with tumorigenesis, immunosuppression, proliferation, metastasis and poor prognosis in human cancers. In response to IL-4/13, STAT6 is phosphorylated, dimerizes and triggers transcriptional regulation after recruitment of coactivators to transcriptosome, such as CBP/p300, SRC-1, PARP-14 and PSF. Post-translational modifications, including phosphorylation, ubiquitination, ADP-ribosylation and acetylation, have been explored for molecular mechanisms of STAT6 in tumor development and management. STAT6 has been developed as a specific biomarker for distinguishing and diagnosing tumor phenotypes, although it is observed to be frequently mutated in metastatic tumors. In this article, we focus mainly on the structural characteristics of STAT6 and its role in tumor growth and progression.

Opioid-Mediated HIV-1 Immunopathogenesis

Despite the ability of combination antiretroviral therapy to dramatically suppress viremia, the brain continues to be a reservoir of HIV-1 low-level replication. Adding further complexity to this is the comorbidity of drug abuse with HIV-1 associated neurocognitive disorders and neuroHIV. Among several abused drugs, the use of opiates is highly prevalent in HIV-1 infected individuals, both as an abused drug as well as for pain management. Opioids and their receptors have attained notable attention owing to their ability to modulate immune functions, in turn, impacting disease progression. Various cell culture, animal and human studies have implicated the role of opioids and their receptors in modulating viral replication and virus-mediated pathology both positively and negatively. Further, the combinatorial effects of HIV-1/HIV-1 proteins and morphine have demonstrated activation of inflammatory signaling in the host system. Herein, we summarized the current knowledge on the role of opioids on peripheral immunopathogenesis, viral immunopathogenesis, epigenetic profiles of the host and viral genome, neuropathogenesis of SIV/SHIV-infected non-human primates, blood-brain-barrier, HIV-1 viral latency, and viral rebound. Overall, this review provides recent insights into the role of opioids in HIV-1 immunopathogenesis. Graphical abstract.

Tn Antigen Expression Contributes to an Immune Suppressive Microenvironment and Drives Tumor Growth in Colorectal Cancer

Expression of the tumor-associated glycan Tn antigen (αGalNAc-Ser/Thr) has been correlated to poor prognosis and metastasis in multiple cancer types. However, the exact mechanisms exerted by Tn antigen to support tumor growth are still lacking. One emerging hallmark of cancer is evasion of immune destruction. Although tumor cells often exploit the glycosylation machinery to interact with the immune system, the contribution of Tn antigen to an immunosuppressive tumor microenvironment has scarcely been studied. Here, we explored how Tn antigen influences the tumor immune cell composition in a colorectal cancer (CRC) mouse model. CRISPR/Cas9-mediated knock out of the C1galt1c1 gene resulted in elevated Tn antigen levels on the cell surface of the CRC cell line MC38 (MC38-Tn^high). RNA sequencing and subsequent GO term enrichment analysis of our Tn^high glycovariant not only revealed differences in MAPK signaling and cell migration, but also in antigen processing and presentation as well as in cytotoxic T cell responses. Indeed, MC38-Tn^high tumors displayed increased tumor growth in vivo, which was correlated with an altered tumor immune cell infiltration, characterized by reduced levels of cytotoxic CD8⁺ T cells and enhanced accumulation of myeloid-derived suppressor cells. Interestingly, no systemic differences in T cell subsets were observed. Together, our data demonstrate for the first time that Tn antigen expression in the CRC tumor microenvironment affects the tumor-associated immune cell repertoire.

Signal transducer and activator of transcription 6 as a target in colon cancer therapy

Signal transducer and activator of transcription 6 (STAT6) is a member of the STAT family of proteins that serve key roles in the initiation of tumorigenesis and malignant transformation. STAT6 is highly expressed in several types of cancer, including breast, pancreatic, prostate and colorectal cancer. STAT6 transduces signals in response to the binding of interleukin (IL)-4 and IL-13 to their receptors and regulates the expression of genes involved in the immune response, cell survival, tumor proliferation and metastasis. Patients with colorectal cancer exhibit high STAT6 activity in the colonic epithelium, and STAT6 expression is associated with lower survival rates, lymph node metastasis, changes in the epithelial barrier function and alterations in the inflammatory response. A number of studies investigating experimental models and cancer cell lines have revealed that STAT6 is associated with tumor growth and development, as well as with increased invasion and metastasis, suggesting that STAT6 inhibition may serve as a novel therapeutic strategy in colon cancer. The present review summarizes the evidence with regard to the implications of STAT6 in cancer biology and the direct and indirect effects on colon tumor transformation. Furthermore, the current treatment strategies targeting the IL-4/IL-13/STAT6 axis in colon cancer are discussed.

Morphine induces the differentiation of T helper cells to Th2 effector cells via the PKC-θ-GATA3 pathway

BACKGROUND

T help 2 (Th2) cell differentiation by morphine has been verified. However, the underlying mechanism of morphine induces Th2 cell differentiation remains elusive. The aim of the present study was to explore the possible basis of morphine induced Th2 cell differentiation.

METHODS

Flow cytometry analysis was used to detect the content of T help 1(Th1) cell and Th2 cell. Enzyme linked immunosorbent assay (ELISA) was performed to determine the levels of IL-4 and IFN-γ. Real-time quantitative polymerase chain reaction, electrophoretic mobility shift assay and Western blotting was conducted in this study.

RESULTS

Th2 cell subset and IL-4 level were elevated in morphine induced naïve T cells. Pathway determining found the protein phosphorylation level of PKC-θ and the expression and activity of the transcription factor GATA3 was also enhanced in the naïve T cells challenged by morphine. Moreover, inhibitor of morphine(naltrexone) or PKC-θ(AEB071) can reverse morphine-induced Th2 cell differentiation.

CONCLUSION

These results suggested that morphine induce naïve T cell differentiation to Th2 cells via the PKC-θ/GATA3 signal pathway.

Prognostic significance of elevated preoperative neutrophil-to-lymphocyte ratio for patients with colorectal cancer undergoing curative surgery: A meta-analysis

BACKGROUND

Preoperative neutrophil-to-lymphocyte ratio (NLR) has been suggested as a useful predictive factor for prognosis in patients with various cancers. However, the prognostic value of NLR in patients with colorectal cancer (CRC) remains controversial. Therefore, the goal of this study was to perform a meta-analysis to evaluate the prognostic value of NLR in patients with CRC undergoing curative surgery.

METHODS

PubMed, EMBASE and Cochrane Library databases were searched to screen the relevant studies. Pooled hazard ratio (HR) with 95% confidence interval (CI) was used to assess the associations of preoperative NLR and overall survival (OS), disease-free survival (DFS), recurrence free survival (RFS) and disease specific survival (DSS) by STATA 13.0 software.

RESULTS

Sixteen studies involving 5897 patients were included in our meta-analysis. Our pooled results demonstrated that high NLR was associated with poor OS (HR: 1.66, 95%CI: 1.36-2.02, P < .001), DFS (HR = 1.54, 95%CI: 1.18-2.02, P = .002), RFS (HR = 2.31, 95%CI: 1.68-3.17, P < .001) and DSS (HR = 2.27; 95% CI: 1.75-2.96, P < .001). When the patients were stratified according to country, sample size, NLR cut-off, follow up and postoperative chemotherapy, high NLR was still significantly correlated with OS. The limitation was that the majority of enrolled studies were retrospective.

CONCLUSION

Preoperative NLR may be an effective predictive biomarker for prognosis in patients with CRC. Detection of NLR may be beneficial to identify the high-risk patients who need other antitumor therapies in addition to surgery.

Activated grass carp STAT6 up-regulates the transcriptional level and expression of CCL20 and Bcl-xl

In mammals, signal transducer and activator of transcription 6 (STAT6) is a broad-spectrum transcriptional regulator involved in cellular immune responses and apoptosis by regulating the immune-related genes and various functional genes. The structure, expression and tyrosine-based phosphorylation of STAT6 are conserved from fish to mammal. However, except the sporadic reports from zebra fish, the function of fish STAT6 has not been well reported. Here, we cloned and characterized the full length cDNA sequence of grass carp (Ctenopharyngodon idella) STAT6 (CiSTAT6). Meanwhile, the activation mechanism and the potential function of CiSTAT6 were studied. The full length cDNA of CiSTAT6 is 2747 bp with an ORF of 2313 bp encoding a polypeptide of 770 amino acids. Phylogenetic tree analysis revealed that CiSTAT6 shares the maximum homology with Cyprinus carpio STAT6. CiSTAT6 was significantly up-regulated and interacted with each other to form the homodimer after treatment with poly I:C. The transfected CiSTAT6 in fish cell lines can activate the promoter activities of CCL20 and Bcl-xl and increase their mRNA levels. In addition, we also found that CiSTAT6 can increase cell viability and inhibit cell apoptosis. Taken together, grass carp STAT6 plays an important part in innate immunity and anti-apoptosis.

IL-13/STAT6 signaling plays a critical role in the epithelial-mesenchymal transition of colorectal cancer cells

Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide due to the distant metastases. Compelling evidence has reported that epithelial-mesenchymal transition (EMT) is involved in promoting cancer invasion and metastasis. However, the precise molecular events that initiate this complex EMT process remain poorly understood. Here, we showed that the pleiotropic cytokine interleukin-13 (IL-13) could induce an aggressive phenotype displaying EMT by enhancing the expression of EMT-promoting factor ZEB1. Importantly, STAT6 signaling inhibitor and STAT6 knockdown significantly reversed IL-13-induced EMT and ZEB1 induction in CRC cells, whereas ectopic STAT6 expression in STAT6^null CRC cell line markedly promoted EMT in the present of IL-13. ChIP-PCR and Luciferase assays revealed that activated STAT6 directly bound to the promoter of ZEB1. Otherwise, we found IL-13 also up-regulated the stem cell markers (nanog, CD44, CD133 and CD166) and promoted cell migration and invasion through STAT6 pathway. We also found that siRNA-mediated knockdown of IL-13Rα1 could reverse IL-13-induced ZEB1 and EMT changes by preventing STAT6 signaling. Finally, we demonstrated positive correlation between IL-13Rα1 and ZEB1 at mRNA levels in human CRC samples. Taken together, our findings first demonstrated that IL-13/IL-13Rα1/STAT6/ZEB1 pathway plays a critical role in promoting EMT and aggressiveness of CRC.

Lack of STAT6 Attenuates Inflammation and Drives Protection against Early Steps of Colitis-Associated Colon Cancer

Colitis-associated colon cancer (CAC) is one of the most common malignant neoplasms and a leading cause of death. The immunologic factors associated with CAC development are not completely understood. Signal transducer and activator of transcription 6 (STAT6) is part of an important signaling pathway for modulating intestinal immune function and homeostasis. However, the role of STAT6 in colon cancer progression is unclear. Following CAC induction in wild-type (WT) and STAT6-deficient mice (STAT6^-/-), we found that 70% of STAT6^-/- mice were tumor-free after 8 weeks, whereas 100% of WT mice developed tumors. STAT6^-/- mice displayed fewer and smaller colorectal tumors than WT mice; this reduced tumorigenicity was associated with decreased proliferation and increased apoptosis in the colonic mucosa in the early steps of tumor progression. STAT6^-/- mice also exhibited reduced inflammation, diminished concentrations COX2 and nuclear β-catenin protein in the colon, and decreased mRNA expression of IL17A and TNFα, but increased IL10 expression when compared with WT mice. Impaired mucosal expression of CCL9, CCL25, and CXCR2 was also observed. In addition, the number of circulating CD11b⁺Ly6C^hiCCR2⁺ monocytes and CD11b⁺Ly6C^lowLy6G⁺ granulocytes was both decreased in a STAT6-dependent manner. Finally, WT mice receiving a STAT6 inhibitor in vivo confirmed a significant reduction in tumor load as well as less intense signs of CAC. Our results demonstrate that STAT6 is critical in the early steps of CAC development for modulating inflammatory responses and controlling cell recruitment and proliferation. Thus, STAT6 may represent a promising target for CAC treatment. Cancer Immunol Res; 5(5); 385-96. ©2017 AACR.

Interleukin-13 interferes with activation-induced t-cell apoptosis by repressing p53 expression

The etiology and the underlying mechanism of CD4(+) T-cell polarization are unclear. This study sought to investigate the mechanism by which interleukin (IL)-13 prevents the activation-induced apoptosis of CD4(+) T cells. Here we report that CD4(+) T cells expressed IL-13 receptor α2 in the intestine of sensitized mice. IL-13 suppressed both the activation-induced apoptosis of CD4(+) T cells and the expression of p53 and FasL. Exposure to recombinant IL-13 inhibited activation-induced cell death (AICD) along with the expression of p53, caspase 3, and tumor necrosis factor-α in CD4(+) T cells. Administration of an anti-IL-13 antibody enhanced the effect of specific immunotherapy on allergic inflammation in the mouse intestine, enforced the expression of p53 in intestinal CD4(+) T cells, and enhanced the frequency of CD4(+) T-cell apoptosis upon challenge with specific antigens. In summary, blocking IL-13 enhances the therapeutic effect of antigen-specific immunotherapy by regulating apoptosis and thereby enforcing AICD in CD4(+) T cells.

Human papillomavirus infection correlates with inflammatory Stat3 signaling activity and IL-17 level in patients with colorectal cancer

Background

Colorectal cancer (CRC) is a major burden of public health and healthcare worldwide. Microbiota has been suggested in promoting chronic inflammation in the intestine which, in turn, promotes tumor development. This study focuses on possible correlations of human papillomavirus (HPV) infection with proinflammatory Stat3 signaling activities and the resulting levels of its downstream proinflammatory cytokine IL-17 in CRC patients.

Methods

HPV was examined using HPV Genotyping Chip technology and constitutively active Stat3 (p-Stat3) and IL-17 levels were tested using immunohistochemistry (IHC) in paraffin-embedded cancerous and adjacent normal tissues (ANT) from a cohort of 95 CRC patients. Correlation analyses were performed between HPV infection and clinicopathological characteristics, Stat3 activities and IL-17 levels among these CRC patients.

Results

Three major findings were observed: (1) HPV infection existed in a high rate of CRC cases (48.4%, 46/95), of which 45 cases (45/46, 97.8%) were high-risk HPV16-positive and only one case was HPV53-positive. (2) HPV infection correlated with poorer clinical stages (III+IV) of CRC. (3) HPV infection strongly correlated with both constitutively higher Stat3 activities (P<0.01) and higher IL-17 levels (P<0.01) only in CRC tissues but not in ANT tissues.

Conclusions

HPV infection is common in CRC patients suggesting potentially preventive effectiveness of HPV vaccination among high-risk young individuals. We have for the first time revealed a tri-lateral relationship among HPV infection, constitutive Stat3 activity and IL-17 level, whose collaborative act may orchestrate a proinflammatory microenvironment in the colorectum that, in turn, may promote carcinogenesis and possibly facilitate progression of CRC.

STAT6 silencing up-regulates cholesterol synthesis via miR-197/FOXJ2 axis and induces ER stress-mediated apoptosis in lung cancer cells

MiRNAs and transcription factors have emerged as important regulators for gene expression and are known to regulate various biological processes, including cell proliferation, differentiation and apoptosis. Previously, using genome-wide expression profiling studies, we have shown an inverse relationship of STAT6 and cholesterol biosynthesis and also identified FOXJ2 binding sites in the upstream region of 3 key genes (HMGCR, HMGCS1 and IDI1) of the cholesterol synthesis pathway. Our previous study also provided clues toward the anti-apoptotic role played by STAT6. For better understanding of the cellular response and underlying signaling pathways activated by STAT6 silencing, we examined the changes in miRNome profile after the siRNA-mediated silencing of STAT6 gene in NCI-H460 cells using LNA-based miRNA microarray. Our analysis showed significant downregulation of miRNAs, let-7b and miR-197, out of which miR-197 was predicted to target FOXJ2. We here show that miR-197 not only negatively regulates FOXJ2 expression through direct binding to its respective binding site in its 3'UTR but also alters total cholesterol levels by regulating genes associated with cholesterol biosynthesis pathway. We further demonstrated that STAT6 silencing elicited ER stress-mediated apoptosis in NCI-H460 cells through C/EBP homologous protein (CHOP) induction, alteration of BH3 only proteins expression and ROS production. The apoptosis induced by STAT6 downregulation was partially reversed by NAC, the ROS scavenger. Based on the above findings, we suggest that ER stress plays a major role in STAT6-induced apoptosis.

Downregulation of Runx3 is closely related to the decreased Th1-associated factors in patients with gastric carcinoma

Runt-related transcription factor 3 (Runx3) is a tumor-suppressor gene and plays an important role in immune regulation, whose reduced expression may play an important role in the development and progression of gastric carcinoma. The aim of this study was to investigate the role of Runx3 on the levels of transcription factors in patients with gastric carcinoma and analyze the relationship between the expression of Runx3 and Th1-type cytokines in peripheral blood mononuclear cells (PBMCs). Our results showed that the expression levels of Runx3, T-bet, and IFN-γ in patients with gastric carcinoma were obviously lower than those in control groups, and there was a positive correlation between the expression of Runx3 and T-bet or IFN-γ in patients (p < 0.01). In order to further confirm this result, the Runx3 gene was constructed into pIRES2-eGFP and the recombined plasmid was transfected into SGC-7901 cells with liposome in vitro, the results obtained from the reverse transcription PCR indicated that the mRNA of Runx3, T-bet, or IFN-γ was significantly upregulated individually in Runx3 gene-transfected SGC-7901 cells. It suggested that the Runx3 and Th1-associated factors including T-bet and IFN-γ synchronization declines in gastric carcinoma may contribute to the development of cancer.

Regulation of alternative splicing of CD44 in cancer

CD44 is a hyaluronan binding cell surface signal transducing receptor that influences motility, cell survival and proliferation as well as the formation of tumor microenvironment. CD44 contains two variable regions encoded by variable exons. Alternative splicing, which is often deregulated in cancer, can produce various isoforms of CD44 with properties that may have different tissue specific effects and therefore even diverse effects on cancer progression. This review summarizes and puts together all major regulators of alternative splicing of CD44 in cancer that have been documented so far and that have an experimentally proved effect on CD44 isoform switching. It is important to better understand the mechanisms of alternative splicing of CD44, where all the variability of CD44 originates, to be able to explain the isoform switching and occurrence of variant isoforms of CD44 (CD44v) in cancer.

TSLP induces mast cell development and aggravates allergic reactions through the activation of MDM2 and STAT6

Thymic stromal lymphopoietin (TSLP) is known to promote T helper type 2 cell-associated inflammation. Mast cells are major effector cells in allergic inflammatory responses. We noted that the population and maturation of mast cells were reduced in TSLP-deficient mice (TSLP-/-). Thus, we hypothesized that TSLP might affect mast cell development. We found that TSLP induced the proliferation and differentiation of mast cells from bone marrow progenitors. TSLP-induced mast cell proliferation was abolished by depletion of mouse double minute 2 (MDM2) and signal transducers and activators of transcription 6 (STAT6), as an upstream activator of MDM2. TSLP-/-, in particular, had a considerable deficit in the expression of MDM2 and STAT6. Also, the TSLP deficiency attenuated mast cell-mediated allergic reactions through the downregulation of STAT6 and MDM2. In an antibody microarray chip analysis, MDM2 expression was increased in atopic dermatitis patients. These observations indicate that TSLP is a factor for mast cell development, and that it aggravates mast cell-mediated immune responses.

STAT6 siRNA matrix-loaded gelatin nanocarriers: formulation, characterization, and ex vivo proof of concept using adenocarcinoma cells

The clinical utility of siRNA therapy has been hampered due to poor cell penetration, nonspecific effects, rapid degradation, and short half-life. We herewith proposed the formulation development of STAT6 siRNA (S6S) nanotherapeutic agent by encapsulating them within gelatin nanocarriers (GNC). The prepared nanoformulation was characterized for size, charge, loading efficiency, release kinetics, stability, cytotoxicity, and gene silencing assay. The stability of S6S-GNC was also assessed under conditions of varying pH, serum level, and using electrophoretic assays. In vitro cytotoxicity performance was evaluated in human adenocarcinoma A549 cells following MTT assay. The developed formulation resulted in an average particle size, surface charge, and encapsulation efficiency as 70 ± 6.5 nm, +10 ± 1.5 mV, and 85 ± 4.0%, respectively. S6S-GNC showed an insignificant (P < 0.05) change in the size and charge in the presence of buffer solutions (pH 6.4 to 8.4) and FBS (10% v/v). A549 cells were treated with native S6S, S6S-lipofectamine, placebo-GNC, and S6S-GNC using untreated cells as a control. It was observed that cell viability was decreased significantly with S6S-GNC by 55 ± 4.1% (P < 0.001) compared to native S6S (2.0 ± 0.55%) and S6S-lipofectamine complex (40 ± 3.1%). This investigation infers that gelatin polymer-based nanocarriers are a robust, stable, and biocompatible strategy for the delivery of siRNA.

Supraglottic laryngeal tumor microenvironmental factors facilitate STAT3 dependent pro-tumorigenic switch in tumor associated macrophages to render utmost immune evasion

Content of tumor microenvironment (TME) is varied greatly among different types of laryngeal tumors, namely, supraglottic, glottic and subglottic tumors. These three different TMEs shape infiltrating monocytes/macrophages toward M2 genotypes in variable degrees. Results obtained from in vitro studies demonstrated extent of expression of M2 phenotypic features on macrophages was maximum after their exposure to supraglottic laryngeal tumor cell lysates (SLTCL) than glottic or subglottic lysates. Moreover, M2 macrophages generated under influence of SLTCL show less nitric oxide production, greater IL-10: IL-12 ratio and poor antigen presentation. Co-culture of such M2 macrophages with T cells from healthy donors resulted decreased activation of T cells and T cell mediated tumor cell cytotoxicity, than, glottic or subglottic. SLTCL mediated macrophage polarization is STAT3 dependent and might be one of the major factors for severe immune paralysis leading to poor prognosis of supraglottic laryngeal tumor bearer following standard treatment.

Downregulation of Hlx closely related to the decreased expressions of T-bet and Runx3 in patients with gastric cancer may be associated with a pathological event leading to the imbalance of Th1/Th2

T-bet plays an important role in immunoregulation; it induces the differentiation of Th1 together with the homeobox transcription factor gene Hlx. Recent studies show that T-bet and Th1-associated factors are critical in regulating tumor development. However, the contributions of Hlx in the occurrence and development of cancer remain unknown. In this study, the Hlx, T-bet, Runx3, and IFN-γ were measured in PBMC from patients with gastric cancer and the correlation between Hlx and T-bet or IFN-γ was assessed. The expression levels of Hlx, T-bet, and IFN-γwere significantly decreased, and there was a positive correlation between Hlx and T-bet or IFN-γ. In addition, the Runx3 expression was also downregulated with the lower T-bet mRNA level. These results suggested that the decreased Hlx expression was closely associated with T-bet and Runx3 downregulations and may contribute to the development of gastric cancer.

Regulation of inflammation by interleukin-4: a review of "alternatives"

Studies of IL-4 have revealed a wealth of information on the diverse roles of this cytokine in homeostatic regulation and disease pathogenesis. Recent data suggest that instead of simple linear regulatory pathways, IL-4 drives regulation that is full of alternatives. In addition to the well-known dichotomous regulation of Th cell differentiation by IL-4, this cytokine is engaged in several other alternative pathways. Its own production involves alternative mRNA splicing, yielding at least two functional isoforms: full-length IL-4, encoded by the IL-4 gene exons 1-4, and IL-4δ2, encoded by exons 1, 3, and 4. The functional effects of these two isoforms are in some ways similar but in other ways quite distinct. When binding to the surface of target cells, IL-4 may differentially engage two different types of receptors. By acting on macrophages, a cell type critically involved in inflammation, IL-4 induces the so-called alternative macrophage activation. In this review, recent advances in understanding these three IL-4-related branch points--alternative splicing of IL-4, differential receptor engagement by IL-4, and differential regulation of macrophage activation by IL-4--are summarized in light of their contributions to inflammation.