IL-4/Stat6 activities correlate with apoptosis and metastasis in colon cancer cells

Apoptotic effect of 5-fluorouracil-doxorubicin combination on colorectal cancer cell monolayers and spheroids

BACKGROUND

Drug combination studies help to improve new treatment approaches for colon cancer. Tumor spheroids (3D) are better models than traditional 2-dimensional cultures (2D) to evaluate cellular responses to chemotherapy drugs. The cultivation of cancer cells in 2D and 3D cultures affects the apoptotic process, which is a major factor influencing the response of cancer cells to chemotherapeutic drugs. In this study, the antiproliferative effects of 5-fluorouracil (5-FU) and doxorubicin (DOX) were investigated separately and in combination using 2D and 3D cell culture models on two different colon cancer cell lines, HT-29 (apoptosis-resistant cells) and Caco-2 2 (apoptosis-susceptible cells).

METHODS

The effect of the drugs on the proliferation of both colon cancer cells was determined by performing an MTT assay in 2D culture. The apoptotic effect of 5-FU and DOX, both as single agents and in combination, was assessed in 2D and 3D cultures through quantitative real-time polymerase chain reaction analysis. The expression of apoptotic genes, such as caspases, p53, Bax, and Bcl-2, was quantified.

RESULTS

It was found that the mRNA expression of proapoptotic genes was significantly upregulated, whereas the mRNA expression of the antiapoptotic Bcl-2 gene was significantly downregulated in both colon cancer models treated with 5-FU, DOX, and 5-FU + DOX.

CONCLUSION

The results indicated that the 5-FU + DOX combination therapy induces apoptosis and renders 5-FU and DOX more effective at lower concentrations compared to their alone use. This study reveals promising results in reducing the potential side effects of treatment by enabling the use of lower drug doses.

AF9 targets acetyl-modified STAT6 to diminish purine metabolism and accelerate cell apoptosis during metastasis

Cell migration and invasion are two important steps for tumour metastasis, and involved the behaviors including metabolism remodeling and anti-apoptosis. However, it's still elusive that cancer cells how to antagonize apoptosis during tumour metastasis. In this study, we observed that super elongation complex (SEC) subunit AF9 depletion exacerbated cell migration and invasion but reduced the apoptosis during invasive migration. Mechanically, AF9 targeted acetyl (Ac)-STAT6 at lysine (K) 284 and blocked STAT6 transactivation on the promoter of such genes involved in regulating purine metabolism and metastasis, in turn induced apoptosis of suspended cells. Of note, AcSTAT6-K284 was not induced by IL4 signaling but decreased by limited nutrition which triggered SIRT6 to remove acetyl group at STAT6-K284. The functional experiments proved that AcSTAT6-K284 attenuated cell migration and invasion depending on AF9 expression level. Animal metastatic study further confirmed the AF9/AcSTAT6-K284 axis existed and blocked kidney renal clear cell carcinoma (KIRC) metastasis. In clinical, both AF9 expression and AcSTAT6-K284 were decreased accompanied by the advanced tumour grade and positively correlated with KIRC patients' survival. Conclusively, we explored an inhibitory axis which not only suppressed tumour metastasis but also could be utilized for drug development to hamper KIRC metastasis.

A comprehensive review on RNA interference-mediated targeting of interleukins and its potential therapeutic implications in colon cancer

Colon cancer is the world's fourth leading cause of death. It is cancer of the latter part of the large intestine, i.e. the colon. Chronic inflammation over a long period also leads to the development of cancer. Cancer in the colon region is arduous to diagnose and is detected at a later stage when it metastasizes to other parts of the body like the liver, lungs, peritoneum, etc. Colon cancer is a great example of solid tumours associated with chronic inflammation. Although conventional therapies are effective, they lose their effectiveness beyond a certain point. Relapse of the disease occurs frequently. RNA interference (RNAi) is emerging as a great tool to specifically attack the cancer cells of a target site like the colon. RNAi deals with epigenetic changes made in the defective cells which ultimately leads to their death without harming the healthy cells. In this review, two types of epigenetic modulators have been considered, namely siRNA and miRNA, and their effect on interleukins. Interleukins, a class of cytokines, are major inflammatory responses of the body that are released by immune cells like leukocytes and macrophages. Some of these interleukins are pro-inflammatory, thereby promoting inflammation which eventually causes cancer. RNAi can prevent colon cancer by inhibiting pro-inflammatory interleukins.

A new insight in immunomodulatory impact of botanicals in treating avian coccidiosis

Avian coccidiosis is caused by genus Eimeria (E.) i.e. E. maxima, E. necatrix, E. tenella, E. acervulina, E. brunette and E. mitis and lead to three billion US dollar per year economic loss in poultry industry and reduces the growth performance of birds. To purge undesirable foreign agents, immune system produces a variety of molecules and cells that ultimately neutralize target particles in healthy organisms. However; when this particular system compromises, infection develops and the load of pathogens along with their virulence factors overcome both; innate and adaptive immune systems. Livestock and poultry sectors are important part of agriculture industry worldwide. Due to excessive use of chemotherapeutic agents, pathogens have developed resistance against these agents leading to the great economic losses. Numerous therapeutic approaches are in routine process for the treatment and prevention of various ailments but irrational use of antibiotics/chemicals has raised alarming concerns, like the development of drug resistant strains, residual effects in ultimate users and environmental pollution. These problems have led to the development of alternatives. In this regard, anticoccidial vaccine can be used as an alternative but due to high cost of production, plant derived biological response modifiers and antioxidants compounds are considered as a promising alternative. This review summarizes the immunotherapeutic effects of different compounds particularly with reference to avian coccidiosis.

Endotoxin contamination alters macrophage-cancer cell interaction and therapeutic efficacy in pre-clinical 3D in vitro models

The rapid developments in biofabrication, in particular 3D bioprinting, in the recent years have facilitated the need for novel biomaterials that aim to replicate the target tissue in great detail. The presence of endotoxins in these biomaterials is often an overlooked problem. In pre-clinical 3D in vitro models, endotoxins can have significant influence on cell behavior and credibility of the model. In this study we demonstrate the effects of high levels of endotoxins in commercially-available gelatin on the macrophage-cancer cell crosstalk in a 3D bioprinted co-culture model. First, it is demonstrated that, while presenting the same mechanical and structural stimuli, high levels of endotoxin can have significant influence on the metabolic activity of macrophages and cancer cells. Furthermore, this study shows that high endotoxin contamination causes a strong inflammatory reaction in macrophages and significantly inhibits the effects of a paracrine macrophage-cancer cell co-culture. At last, it is demonstrated that the differences in endotoxin levels can drastically alter the efficacy of novel macrophage modulating immunotherapies, AS1517499 and 3-methyladenine. Altogether, this study shows that endotoxin contamination in biomaterials can significantly alter intra- and intercellular communication and thereby drug efficacy, which might lead to misinterpretation of the potency and safety of the tested compounds.

Hematopoietic Prostaglandin D2 Synthase Controls Tfh/Th2 Communication and Limits Tfh Antitumor Effects

T follicular helper (Tfh) cells are a subset of CD4+ T cells essential in immunity and have a role in helping B cells produce antibodies against pathogens. However, their role during cancer progression remains unknown. The mechanism of action of Tfh cells remains elusive because contradictory data have been reported on their protumor or antitumor responses in human and murine tumors. Like Tfh cells, Th2 cells are also involved in humoral immunity and are regularly associated with tumor progression and poor prognosis, mainly through their secretion of IL4. Here, we showed that Tfh cells expressed hematopoietic prostaglandin D2 (PGD2) synthase in a pSTAT1/pSTAT3-dependent manner. Tfh cells produced PGD2, which led to recruitment of Th2 cells via the PGD2 receptor chemoattractant receptor homologous molecule expressed on Th type 2 cells (CRTH2) and increased their effector functions. This cross-talk between Tfh and Th2 cells promoted IL4-dependent tumor growth. Correlation between Th2 cells, Tfh cells, and hematopoietic PGD2 synthase was observed in different human cancers and associated with outcome. This study provides evidence that Tfh/Th2 cross-talk through PGD2 limits the antitumor effects of Tfh cells and, therefore, could serve as a therapeutic target.

The Emerging Role of Janus Kinase Inhibitors in the Treatment of Cancer

Cancer is a leading cause of death worldwide. The Janus kinase (JAK) signal transducer and activator of transcription (STAT) signalling pathway is activated abnormally, which promotes carcinogenesis. Several cytokines are important cancer drivers. These proteins bind to receptors and use the Janus kinase (JAK) and STAT pathways to communicate their responses. Cancer risks are linked to genetic differences in the JAK-STAT system. JAK inhibitors have shown to reduce STAT initiation, tissue propagation, and cell existence in preclinical investigations in solid tumour cell line models. JAK inhibitors, notably ruxolitinib, a, JAK1 or 2 blockers, make cell lines and mouse models more susceptible to radiotherapy, biological response modifier therapy, and oncolytic viral treatment. Numerous JAK antagonists have been or are now being evaluated in cancerous patients as monotherapy or by combining with other drugs in clinical studies. In preclinical investigations, certain JAK inhibitors showed promise anticancer effects; however, clinical trials explicitly evaluating their effectiveness against the JAK/STAT system in solid tumours have yet to be completed. JAK inhibition is a promising strategy to target the JAK/STAT system in solid tumours, and it deserves to be tested further in clinical studies. The function of directing Janus kinases (JAKs), an upstream accelerator of STATs, as a technique for lowering STAT activity in various malignant circumstances is summarized in this article, which will help scientists to generate more specific drug molecules in future.

Rab1A promotes IL-4R/JAK1/STAT6-dependent metastasis and determines JAK1 inhibitor sensitivity in non-small cell lung cancer

Rab1A overexpression has been observed in several cancer types, however, its significance and the underlying mechanisms in non-small cell lung cancer (NSCLC) remain largely unexplored. This study demonstrated that Rab1A overexpression in NSCLC was significantly correlated to short survival and metastasis. Rab1A overexpression promoted cancer cell migration, invasion, and metastasis both in vitro and in vivo, by activating JAK1/STAT6 signaling through stabilizing IL-4Rα protein. Strikingly, high Rab1A level was associated with sensitivity to JAK1 inhibitor, and Rab1A overexpression rendered cancer cells vulnerable to JAK1-targeted agents. JAK1 inhibitor, Itacitinib adipate, dramatically inhibited high Rab1A NSCLC metastasis, in both cell line and patient derived xenograft models. Collectively, these findings demonstrated that Rab1A plays a critical role in the aggressive properties of NSCLC, revealing a unique mechanism by which it promotes metastasis. In addition, we found that Rab1A is a determinant of JAK1 inhibitor sensitivity, which could be explored for improving JAK1-targeted cancer therapy.

STAT6 Is Critical for the Induction of Regulatory T Cells In Vivo Controlling the Initial Steps of Colitis-Associated Cancer

Inflammation is the main driver of the tumor initiation and progression in colitis-associated colorectal cancer (CAC). Recent findings have indicated that the signal transducer and activator of transcription 6 (STAT6) plays a fundamental role in the early stages of CAC, and STAT6 knockout (STAT6^−/−) mice are highly resistant to CAC development. Regulatory T (Treg) cells play a major role in coordinating immunomodulation in cancer; however, the role of STAT6 in the induction and function of Treg cells is poorly understood. To clarify the contribution of STAT6 to CAC, STAT6^−/− and wild type (WT) mice were subjected to an AOM/DSS regimen, and the frequency of peripheral and local Treg cells was determined during the progression of CAC. When STAT6 was lacking, a remarkable reduction in tumor growth was observed, which was associated with decreased inflammation and an increased number of CD4+CD25+Foxp3+ cells in the colon, circulation, and spleen, including an over-expression of TGF-beta, IL-10, and Foxp3, compared to WT mice, during the early stages of CAC development. Conversely, WT mice showed an inverse frequency of Treg cells compared with STAT6^−/− mice, which was followed by intestinal tumor formation. Increased mucosal inflammation, histological damage, and tumorigenesis were restored to levels observed in WT mice when an early inhibition/depletion of Treg cells was performed in STAT6^−/− mice. Thus, with STAT6 deficiency, an increased number of Treg cells induce resistance against tumorigenesis, arresting tumor-promoting inflammation. We reported a direct role of STAT6 in the induction and function of Treg cells during CAC development and suggest that STAT6 is a potential target for the modulation of immune response in colitis and CAC.

Involvement of IL-4, IL-13 and Their Receptors in Pancreatic Cancer

Interleukin (IL)-4 and IL-13 are known as pleiotropic Th2 cytokines with a wide range of biological properties and functions especially in immune responses. In addition, increasing activities have also been determined in oncogenesis and tumor progression of several malignancies. It is now generally accepted that IL-4 and IL-13 can exert effects on epithelial tumor cells through corresponding receptors. Type II IL-4 receptor (IL-4Rα/IL-13Rα1), predominantly expressed in non-hematopoietic cells, is identified to be the main target for both IL-4 and IL-13 in tumors. Moreover, IL-13 can also signal by binding to the IL-13Rα2 receptor. Structural similarity due to the use of the same receptor complex generated in response to IL-4/IL-13 results in overlapping but also distinct signaling pathways and functions. The aim of this review was to summarize knowledge about IL-4 and IL-13 and their receptors in pancreatic cancer in order understand the implication of IL-4 and IL-13 and their receptors for pancreatic tumorigenesis and progression and for developing possible new diagnostic and therapeutic targets.

Possible Roles of Interleukin-4 and -13 and Their Receptors in Gastric and Colon Cancer

Interleukin (IL)-4 and -13 are structurally and functionally related cytokines sharing common receptor subunits. They regulate immune responses and, moreover, are involved in the pathogenesis of a variety of human neoplasms. Three different receptors have been described for IL-4, but only IL-4 receptor type II (IL-4Rα/IL-13Rα1) is expressed in solid tumors. While IL-13 can also bind to three different receptors, IL-13 receptor type I (IL-4Rα/IL-13Rα1/IL-13Rα2) and type II (IL-4Rα/IL-13Rα1) are expressed in solid tumors. After receptor binding, IL-4 and IL-13 can mediate tumor cell proliferation, survival, and metastasis in gastric or colon cancer. This review summarizes the results about the role of IL-4/IL-13 and their receptors in gastric and colon cancer.

High Expression of VSTM2L Induced Resistance to Chemoradiotherapy in Rectal Cancer through Downstream IL-4 Signaling

Background

Preoperative chemoradiotherapy (pCRT) is a common and essential therapeutic strategy for patients with locally advanced rectal cancer (LARC), but poor tumor response and therapeutic resistance to chemoradiotherapy have appeared usually among persons and affected those patients' survival prognosis. The resistance to chemoradiotherapy in rectal cancer is difficult to predict. This study was aimed at evaluating the role of V-set and transmembrane domain containing 2 like protein (VSTM2L) in resistance to chemoradiotherapy in rectal cancer.

Methods

Analysis of the GEO profiling datasets of rectal cancer patients receiving pCRT disclosed that VSTM2L as a candidate gene was significantly upregulated in nonresponders of rectal cancer with pCRT. The mRNA and protein expression of VSTM2L was detected by quantitate real-time PCR, western blotting, and immunohistochemistry in six rectal cancer biopsy tissues before pCRT. Furthermore, the rectal cancer patient-derived organoids were cultured to evaluate the association of VSTM2L expression and tumor response to CRT. Overexpression of VSTM2L in cancer cells treated with CRT was analyzed for the function of cell proliferation and viability, clone formation, DNA damage repair, and apoptosis ability. The GSEA and RNA-sequence analysis were used to find the downstream mechanism of VSTM2L overexpression in cells treated with CRT.

Results

The mRNA levels of VSTM2L were significantly downregulated in normal rectal tissues compared to tumor tissues and were upregulated in nonresponders of rectal cancer patients receiving pCRT and positively correlated with poor survival prognosis from GEO datasets. High expression of VSTM2L was significantly associated with tumor regression after pCRT (P = 0.030). Moreover, high expression of VSTM2L reduced γ-H2AX expression in rectal cancer patient-derived organoids treated with CRT. The overexpression of VSTM2L in colorectal cancer cells induced resistance to CRT via promoting cell proliferation and inhibiting apoptosis. The molecular mechanism revealed that the overexpression of VSTM2L induced resistance to CRT through downstream IL-4 signaling affecting the progress of cell proliferation and apoptosis.

Conclusion

The high expression of VSTM2L induced resistance to CRT, and adverse survival outcomes served as a prognostic factor in patients with rectal cancer receiving pCRT, suggesting that VSTM2L high expression may be a potential resistant predictable biomarker for LARC patients receiving pCRT.

The bioactivity of colostrum and milk exosomes of high, average, and low immune responder cows on human intestinal epithelial cells

Bovine milk contains bioactive components that are nutritionally and immunologically important to calves and humans. Dairy cows classified as high (H) immune responders using the patented high immune response technology have higher concentrations of immunoglobulin and specific antibodies in sera and milk compared with average (A) and low (L) responders. MicroRNA post-transcriptionally regulate expression of milk bioactive components and are enriched in extracellular vesicles known as exosomes, which protect them from degradation. The bioactivity of colostrum and milk exosomes at the human intestinal epithelial barrier remains to be explored, particularly in the context of the high immune response technology. Therefore, the purpose of this study was to evaluate the functional role of bovine milk exosomes compared with colostrum exosomes from H, A, and L responders at the intestinal interface using human colorectal adenocarcinoma epithelial (Caco-2) cells. Exosomes were isolated by successive ultracentrifugation and confirmed by western blot analysis for the presence of common exosomal proteins (CD9, CD63, and heat shock protein 70). Fluorescent labeling of exosomes using PKH67 dye confirmed their uptake by Caco-2 cells, demonstrating their potential bioavailability. The MTT assays showed that colostrum and milk exosomes maintain Caco-2 metabolic activity and are not cytotoxic to these cells. Specifically, metabolic activity after co-incubation with colostrum and milk exosomes from H responder cows was significantly greater than after co-incubation with exosomes from L responders. Caspase 3 activity, an indicator of apoptosis, was significantly lower after co-incubation of Caco-2 cells with milk exosomes compared with colostrum exosomes, suggesting that unlike colostrum exosomes, particularly those from L responders, milk exosomes do not activate the caspase 3 pathway in Caco-2 cells. This study helps us better understand the functional importance of colostrum and milk exosomes from dairy cows and emphasizes differences in functionality among exosomes from H, A, and L immune responders.

Identification and Validation of STAT6 as a Prognostic and Predictive Biomarker in Acute Myeloid Leukemia

BACKGROUND

Acute myeloid leukemia (AML) is one of the most common hematological diseases in adults. The overall survival rate remains unsatisfactory. It is urgent to identify potential prognostic biomarkers and develop new molecular therapeutic strategies for AML. Signal transducer and activator of transcription (STAT) is a family of genes that encode intracellular transcription factors. STATs are associated with leukemogenesis, cellular transformation, and cell cycle in AML.

METHODS

We used sequencing data and clinical data from The Cancer Genome Atlas (TCGA) and ONCOMINE to identify expression difference, gene variability and correlation as well as prognostic effects of STAT genes in AML patients. Then, we verified the expression difference of STAT6 between healthy control and AML patients and its prognostic impact in Gene Expression Omnibus (GEO) database and our own recruited cohort.

RESULTS

The mRNA level of STAT6 was increased in AML patients among TCGA, GEO and ONCOMINE public datasets and was found to be an independent risk factor of overall survival in all AML patients and patients who only received chemotherapy by multivariate analysis. In our study, STAT6 mRNA level was markedly up-regulated in AML patients (n=105) compared to healthy donor (n=39) (P=0.0435) as a validated cohort. Patients that only received chemotherapy in high STAT6 group showed significantly lower overall survival (OS) (P=0.0055).

CONCLUSION

STAT6 expression was increased in AML patients. STAT6 was found to be an adverse prognosis factor in AML patients, especially those who only received chemotherapy treatments.

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.

Nonclassical roles for IFN-γ and IL-10 in a murine model of immunoedition

Aim:

To characterize, by means of univariate and multivariate approaches, the T helper (Th)-1 and Th-2 responses during the different phases of tumor immunoediting.

Materials & methods:

We used a multivariate principal component analysis applied to analyze the joint behavior of serum concentrations of IFN-γ, IL-2, IL-10 and IL-4, during the different phases of tumor immunoediting, in CBi/L mice challenged with M-406 mammary adenocarcinoma.

Results & conclusion:

Animals in equilibrium phase showed the widest variations in values of the four cytokines. In this experimental model, the role of IFN-γ would be related to tumor growth and progression, while IL-10 would participate in the antitumor immune response.

Breast cancer is a complex, multifactor disease that affects about 10% of women in industrialized countries. The immune system has the ability to monitor the appearance of tumors, but the tumors have the ability to escape such rejection. For this reason, in order to design different therapeutic strategies, it is important to know the different mechanisms that take place when a tumor grows or when it is rejected. Here we sought to elucidate some of these mechanisms.

Inhibiting the Activity of NADPH Oxidase in Cancer

Significance: The primary function of NADPH oxidases (NOX1-5 and dual oxidases DUOX1/2) is to produce reactive oxygen species (ROS). If inadequately regulated, NOX-associated ROS can promote oxidative stress, aberrant signaling, and genomic instability. Correspondingly, NOX isoforms are known to be overexpressed in multiple malignancies, thus constituting potential therapeutic targets in cancer. Recent Advances: Multiple genetic studies aimed at suppressing the expression of NOX proteins in cellular and animal models of cancer have provided support for the notion that NOXs play a pro-tumorigenic role. Further, large drug screens and rational design efforts have yielded inhibitor compounds, such as the diphenylene iodonium (DPI) analog series developed by our group, with increased selectivity and potency over "first generation" NOX inhibitors such as apocynin and DPI. Critical Issues: The precise role of NOX enzymes in tumor biology remains poorly defined. The tumorigenic properties of NOXs vary with cancer type, and precise tools, such as selective inhibitors, are needed to deconvolute NOX contribution to cancer development. Most NOX inhibitors developed to date are unspecific, and/or their mechanistic and pharmacological characteristics are not well defined. A lack of high-resolution crystal structures for NOX functional domains has hindered the development of potent and selective inhibitors. Future Directions: In-depth studies of NOX interactions with the tumor microenvironment (e.g., cytokines, cell-surface antigens) will help identify new approaches for NOX inhibition in cancer.

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.

Use of STAT6 Phosphorylation Inhibitor and Trimethylglycine as New Adjuvant Therapies for 5-Fluorouracil in Colitis-Associated Tumorigenesis

Colorectal cancer (CRC) is one of the most widespread and deadly types of neoplasia around the world, where the inflammatory microenvironment has critical importance in the process of tumor growth, metastasis, and drug resistance. Despite its limited effectiveness, 5-fluorouracil (5-FU) is the main drug utilized for CRC treatment. The combination of 5-FU with other agents modestly increases its effectiveness in patients. Here, we evaluated the anti-inflammatory Trimethylglycine and the Signal transducer and activator of transcription (STAT6) inhibitor AS1517499, as possible adjuvants to 5-FU in already established cancers, using a model of colitis-associated colon cancer (CAC). We found that these adjuvant therapies induced a remarkable reduction of tumor growth when administrated together with 5-FU, correlating with a reduction in STAT6-phosphorylation. This reduction upgraded the effect of 5-FU by increasing both levels of apoptosis and markers of cell adhesion such as E-cadherin, whereas decreased epithelial-mesenchymal transition markers were associated with aggressive phenotypes and drug resistance, such as β-catenin nuclear translocation and Zinc finger protein SNAI1 (SNAI1). Additionally, Il-10, Tgf-β, and Il-17a, critical pro-tumorigenic cytokines, were downmodulated in the colon by these adjuvant therapies. In vitro assays on human colon cancer cells showed that Trimethylglycine also reduced STAT6-phosphorylation. Our study is relatively unique in focusing on the effects of the combined administration of AS1517499 and Trimethylglycine together with 5-FU on already established CAC which synergizes to markedly reduce the colon tumor load. Together, these data point to STAT6 as a valuable target for adjuvant therapy in colon cancer.

An Updated Review of Oral Cancer Stem Cells and Their Stemness Regulation

Cancer stem cells (CSCs; also known as tumor-initiating cells) are a small population of cancer cells that retain characteristics similar to those of normal stem cells. CSCs are known to be responsible for metastasis, drug resistance, and cancer recurrence. Thus, controlling CSCs may provide an effective therapeutic intervention that inhibits tumor growth and aggressiveness. Despite the importance of targeting CSCs in cancer therapy, the detailed nature of oral CSCs remains underexplored. This article reviews the current understanding of oral CSCs, with emphasis on recent advances in novel signaling pathways involved in their stemness regulation.

STAT6 knockdown using multiple siRNA sequences inhibits proliferation and induces apoptosis of human colorectal and breast cancer cell lines

The transcription factor STAT6 is strongly expressed in various tumours and is most highly expressed in human malignant lymphomas and pancreatic, colorectal, prostate and breast cancers. STAT6 is associated with cancer cell proliferation, an increased malignancy and poor prognosis. Thus, techniques aimed at reducing or blocking STAT6 expression may be useful in treating STAT6^high cancers. Among these cancers, colorectal and breast cancers represent two of the most common worldwide and their incidence is increasing every year. In 2018, colorectal and breast cancers represented 10.2% and 11.6% of all new cases of cancer diagnosed, respectively. In this study, four proprietary STAT6 specific small interfering RNA (siRNA) sequences were tested in vitro using the human colon adenocarcinoma cell line, HT-29, and the breast/duct carcinoma cell line, ZR-75-1. Decreases in STAT6 mRNA and protein levels were analysed to confirm the transfection was successful and STAT6 knockdown effects were measured by analysing cell proliferation and apoptosis. Results showed that 100nM siRNA concentration was the most effective and, although all individual sequences were capable of significantly inhibiting cell proliferation, STAT6 siRNA sequences 1 and 4 had the largest effects. STAT6 silencing also significantly induced apoptotic events. In conclusion, these results demonstrate that STAT6 siRNA sequences are capable of inhibiting proliferation of and inducing apoptosis of HT-29 colorectal cancer cells and ZR-75-1 breast cancer cells, halving the number of cancer cells in a short period of time. These experiments will be repeated in other STAT6^high cancers in vitro, and animal studies in immunocompromised mice have been planned using xenografts of STAT6-expressing human colorectal and breast cancer cells. The STAT6 siRNA sequences therefore represent a potential treatment for STAT6^high colorectal and breast cancers and a wide variety of other STAT6-expressing cancers.

The Expression Levels of IL-4/IL-13/STAT6 Signaling Pathway Genes and SOCS3 Could Help to Differentiate the Histopathological Subtypes of Non-Small Cell Lung Carcinoma

Background

The interleukin (IL)-4/IL-13/signal transducer and activator of transcription (STAT) 6 signaling pathway and the SOCS3 gene, one of its main regulators, constitute an important link between the inflammation process in the epithelial cells and inflammatory-related tumorigenesis. The present study is the first to evaluate IL-4, IL-13, STAT6, and SOCS3 mRNA expression in non-small cell lung carcinoma (NSCLC) histopathological subtypes.

Methods

Gene expression levels were assessed using TaqMan^® probes by quantitative reverse transcription PCR (qRT-PCR) in lung tumor samples and unchanged lung tissue samples.

Results

Increased expression of IL-4, IL-13, and STAT6 was observed in all histopathological NSCLC subtypes (squamous cell carcinoma [SCC], adenocarcinoma [AC], and large cell carcinoma [LCC]). Significantly higher expression of IL-13 and STAT6 (p = 0.019 and p = 0.008, respectively) was found in SCC than in LCC. No statistically significant differences were found for IL-4. Significantly higher SOCS3 expression was found in LCC than in AC (p = 0.027). A negative correlation (rho = –0.519) was observed for the STAT6 and SOCS3 genes in SCC (p = 0.005). No associations were found between gene expression and tumor staging (post-operative Tumor Node Metastasis [pTNM], American Joint Committee on Cancer [AJCC]), patients’ age, sex, or history of smoking.

Conclusions

As the number of LCC cases in our study was quite low, the statistically significant results obtained should be confirmed in a larger group of patients, particularly as the relationships identified between increased IL-4, IL-13, and STAT6 mRNA expression and decreased SOCS3 expression suggest that these genes may serve as potential diagnostic markers for differentiating between NSCLC histopathological subtypes.

E2F1/SP3/STAT6 axis is required for IL-4-induced epithelial-mesenchymal transition of colorectal cancer cells

Colorectal cancer (CRC) is a type of cancer with a mortality rate among the highest worldwide owing to its high rate of metastasis. Therefore, inflammation-associated metastasis in the development of CRC is currently a topic of considerable interest. In the present study, the pro-inflammatory cytokine interleukin-4 (IL-4) was identified to promote the epithelial-mesenchymal transition (EMT) of CRC cells. However, the enhancing effect of IL-4 was more evident in HCT116 cells compared with in RKO cells. Accordingly, an increased expression level of STAT6 was observed in HCT116 cells compared with RKO cells. Further investigations identified that E2F1 was required for maintaining the level of signal transducer and activator of transcription 6 (STAT6) in HCT116 cells. Mechanistically, E2F1 induced specificity protein 3 (SP3) directly by binding to the promoter of the STAT6 gene and activating its transcription in CRC cells. As a result, phosphorylation-activated STAT6 increased the expression of several EMT drivers, including zinc finger E-box-binding homeobox (Zeb)1 and Zeb2, which serve a critical function in IL-4-induced EMT. Rescue experiments further confirmed that IL-4-induced EMT relied on an intact E2F1/SP3/STAT6 axis in CRC cells. Finally, analysis of clinical CRC specimens revealed a positive correlation between E2F1, SP3 and STAT6. The ectopically expressed E2F1/SP3/STAT6 axis indicated a poor prognosis in patients with CRC. In conclusion, the E2F1/SP3/STAT6 pathway was identified to be essential for IL-4 signaling-induced EMT and aggressiveness of CRC cells.

A Bayesian Gene-Based Genome-Wide Association Study Analysis of Osteosarcoma Trio Data Using a Hierarchically Structured Prior

Osteosarcoma is considered to be the most common primary malignant bone cancer among children and young adults. Previous studies suggest growth spurts and height to be risk factors for osteosarcoma. However, studies on the genetic cause are still limited given the rare occurrence of the disease. In this study, we investigated in a family trio data set that is composed of 209 patients and their unaffected parents and conducted a genome-wide association study (GWAS) to identify genetic risk factors for osteosarcoma. We performed a Bayesian gene-based GWAS based on the single-nucleotide polymorphism (SNP)-level summary statistics obtained from a likelihood ratio test of the trio data, which uses a hierarchically structured prior that incorporates the SNP-gene hierarchical structure. The Bayesian approach has higher power than SNP-level GWAS analysis due to the reduced number of tests and is robust by accounting for the correlations between SNPs so that it borrows information across SNPs within a gene. We identified 217 genes that achieved genome-wide significance. Ingenuity pathway analysis of the gene set indicated that osteosarcoma is potentially related to TP53, estrogen receptor signaling, xenobiotic metabolism signaling, and RANK signaling in osteoclasts.

Recirculating Th2 cells induce severe thymic dysfunction via IL-4/STAT6 signaling pathway

Thymic involution happened early in life, but a certain ratio of activated CD4⁺ T cells will persistently recirculate into the thymus from the periphery and it have been suggested to be able to inhibit the development of embryonic thymocytes. Our present study was aimed to elucidate the specific mechanism how activated CD4⁺ T cells could influence upon developing thymocytes by using fetal thymic organ culture (FTOC) and kidney capsule transplantation. Our results demonstrated that Th2 cells were found to play a fundamental role in the inhibition of embryonic thymocyte development since a very low concentration of Th2 cells could obviously reduce the total number of thymocytes. And this effect was not tenable in other Th cell type. Notably, IL-4, the major cytokine secreted by Th2 cells, was suggested the key factor playing the inhibition role. In addition to reduced cell population, the proportion of double positive (DP) T cells was also heavily decreased. Furthermore, we demonstrated that it was the downstream effector signal transducer and activator of transcription 6 (STAT6) of IL-4 partially manipulate this inhibition. Together, these findings reveal a novel influence of Th2 cells re-entering the thymus on thymic involution.

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.

IL-4, a direct target of miR-340/429, is involved in radiation-induced aggressive tumor behavior in human carcinoma cells

Radiotherapy induces the production of cytokines, thereby increasing aggressive tumor behavior. This radiation effect results in the failure of radiotherapy and increases the mortality rate in patients. We found that interleukin-4 (IL-4) and IL-4Rα (IL-4 receptor) are highly expressed in various human cancer cells subsequent to radiation treatment. In addition, IL-4 is highly overexpressed in metastatic carcinoma tissues compared with infiltrating carcinoma tissues. High expression of IL-4 in patients with cancer is strongly correlated with poor survival. The results of this study suggest that radiation-induced IL-4 contributes to tumor progression and metastasis. Radiation-induced IL-4 was associated with tumorigenicity and metastasis. IL-4 expression was downregulated by miR-340 and miR-429, which were decreased by ionizing radiation (IR). Radiation-regulated miR-340/429-IL4 signaling increased tumorigenesis and metastasis by inducing the production of Sox2, Vimentin, VEGF, Ang2, and MMP-2/9 via activating JAK, JNK, β-catenin, and Stat6 in vitro and in vivo. Our study presents a conceptual advance in our understanding of the modification of tumor microenvironment by radiation and suggests that combining radiotherapy with genetic therapy to inhibit IL-4 may be a promising strategy for preventing post-radiation recurrence and metastasis in patients.

High expression of IL-4R enhances proliferation and invasion of hepatocellular carcinoma cells

OBJECTIVE

In this study, we aimed to investigate the expression and function of interleukin-4 receptor (IL-4R) in hepatocellular carcinoma (HCC).

METHODS

We collected 40 pairs of human HCC and adjacent normal tissue specimens and examined the expression levels of IL-4R. After IL-4R knockdown in HCC cell lines, cell proliferation and invasion ability were examined. Cell cycle and apoptosis were analyzed by flow cytometry. The activity of multiple signaling pathways was examined by Western blot.

RESULTS

IL-4R was overexpressed in HCC tumors compared with adjacent normal control tissues and was associated with tumor differentiation status. IL-4R knockdown resulted in enhanced apoptosis, impaired proliferation and reduced invasion of HCC cells. Furthermore, IL-4R knockdown abolished IL-4-induced activation of the Janus Kinase 1 (JAK1)/signal transducer and activator of transcription 6 (STAT6) and JUN N-terminal kinase (JNK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways.

CONCLUSIONS

IL-4R plays an important role in regulating HCC cell survival and metastasis, and regulates the activity of the JAK1/STAT6 and JNK/ERK1/2 signaling pathways. We therefore suggest that IL-4/IL-4R may be a new therapeutic target for HCC.

The immunosuppressive cytokine interleukin-4 increases the clonogenic potential of prostate stem-like cells by activation of STAT6 signalling

Interleukin-4 plays a critical role in the regulation of immune responses and has been detected at high levels in the tumour microenvironment of cancer patients, where concentrations correlate with the grade of malignancy. In prostate cancer, interleukin-4 has been associated with activation of the androgen receptor, increased proliferation and activation of survival pathways such as Akt and NF-κB. However, its role in therapy resistance has not yet been determined. Here we investigate the influence of interleukin-4 on primary epithelial cells from prostate cancer patients. Our data demonstrate an increase in the clonogenic potential of these cells when cultured in the presence of interleukin-4. In addition, a Phospho-Kinase Array revealed that in contrast to previously published work, signal transducer and activator of transcription6 (STAT6) is the only signalling molecule activated after interleukin-4 treatment. Using the STAT6-specific inhibitor AS1517499 we could confirm the role of STAT6 in increasing colony-forming frequency. However, clonogenic recovery assays revealed that interleukin-4 does not rescue the effects of either irradiation or docetaxel treatment. We therefore propose that although the interleukin-4/STAT6 axis does not appear to be involved in therapy resistance, it does play a crucial role in the colony-forming abilities of the basal cell population in prostate cancer. IL-4 may therefore contribute to disease relapse by providing a niche that is favourable for the clonogenic growth of prostate cancer stem cells.

Spontaneous lung metastasis formation of human Merkel cell carcinoma cell lines transplanted into scid mice

Merkel cell carcinoma (MCC) is an aggressive skin cancer entity that frequently leads to rapid death due to its high propensity to metastasize. The etiology of most MCC cases is linked to Merkel cell polyomavirus (MCPyV), a virus which is monoclonally integrated in up to 95% of tumors. While there are presently no animal models to study the role of authentic MCPyV infection on transformation, tumorigenesis or metastasis formation, xenograft mouse models employing engrafted MCC-derived cell lines (MCCL) represent a promising approach to study certain aspects of MCC pathogenesis. Here, the two MCPyV-positive MCC cell lines WaGa and MKL-1 were subcutaneously engrafted in scid mice. Engraftment of both MCC cell lines resulted in the appearance of circulating tumor cells and metastasis formation, with WaGa-engrafted mice showing a significantly shorter survival time as well as increased numbers of spontaneous lung metastases compared to MKL-1 mice. Interestingly, explanted tumors compared to parental cell lines exhibit an upregulation of MCPyV sT-Antigen expression in all tumors, with WaGa tumors showing significantly higher sT-Antigen expression than MKL-1 tumors. RNA-Seq analysis of explanted tumors and parental cell lines furthermore revealed that in the more aggressive WaGa tumors, genes involved in inflammatory response, growth factor activity and Wnt signalling pathway are significantly upregulated, suggesting that sT-Antigen is the driver of the observed differences in metastasis formation.

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.

NADPH oxidase 1 supports proliferation of colon cancer cells by modulating reactive oxygen species-dependent signal transduction

Reactive oxygen species (ROS) play a critical role in cell signaling and proliferation. NADPH oxidase 1 (NOX1), a membrane-bound flavin dehydrogenase that generates O₂^˙̄, is highly expressed in colon cancer. To investigate the role that NOX1 plays in colon cancer growth, we used shRNA to decrease NOX1 expression stably in HT-29 human colon cancer cells. The 80–90% decrease in NOX1 expression achieved by RNAi produced a significant decline in ROS production and a G₁/S block that translated into a 2–3-fold increase in tumor cell doubling time without increased apoptosis. The block at the G₁/S checkpoint was associated with a significant decrease in cyclin D₁ expression and profound inhibition of mitogen-activated protein kinase (MAPK) signaling. Decreased steady-state MAPK phosphorylation occurred concomitant with a significant increase in protein phosphatase activity for two colon cancer cell lines in which NOX1 expression was knocked down by RNAi. Diminished NOX1 expression also contributed to decreased growth, blood vessel density, and VEGF and hypoxia-inducible factor 1α (HIF-1α) expression in HT-29 xenografts initiated from NOX1 knockdown cells. Microarray analysis, supplemented by real-time PCR and Western blotting, revealed that the expression of critical regulators of cell proliferation and angiogenesis, including c-MYC, c-MYB, and VEGF, were down-regulated in association with a decline in hypoxic HIF-1α protein expression downstream of silenced NOX1 in both colon cancer cell lines and xenografts. These studies suggest a role for NOX1 in maintaining the proliferative phenotype of some colon cancers and the potential of NOX1 as a therapeutic target in this disease.

Inhibition of MDM2 expression by rosmarinic acid in TSLP-stimulated mast cell

Rosmarinic acid (RA) has an anti-inflammatory property while thymic stromal lymphopoietin (TSLP) has an important role in mast cell-mediated inflammatory responses. Thus, the aim of this study was to determine the regulatory effect of RA in TSLP-stimulated human mast cell line, HMC-1 cells, and short ragweed pollen-induced allergic conjunctivitis mouse model. As a result, we found that RA significantly decreased the TSLP-induced mast cell proliferation and murine double minute (MDM) 2 expression. RA significantly decreased the levels of interleukin (IL)-13 and phosphorylated the signal transducer and activation of transcription 6 in the TSLP-stimulated HMC-1 cells. RA induced the increment of p53 levels, caspase-3 activation, and poly-ADP-ribose polymerase cleavage and the reduction of the procaspase-3 and Bcl2. RA significantly reduced the production of tumor necrosis factor-α, IL-1β, and IL-6 on the TSLP-stimulated HMC-1 cells. In addition, RA significantly reduced the levels of IgE, IL-4, and TSLP in the short ragweed pollen-induced allergic conjunctivitis mouse model. In conclusion, the results of the study suggest that RA has a significant anti-inflammatory effect on TSLP-induced inflammatory reactions. These effects of RA are likely to be mediated through inhibiting the MDM2 increased by TSLP.

Elevated expression of JMJD6 is associated with oral carcinogenesis and maintains cancer stemness properties

Cancer stem cells (CSCs) are defined as a small subpopulation of cancer cells within a tumor and responsible for initiation and maintenance of tumor growth. Thus, understanding of molecular regulators of CSCs is of paramount importance for the development of effective cancer therapies. Here, we identified jumonji domain-containing protein 6 (JMJD6) as a novel molecular regulator of oral CSCs. JMJD6 is highly expressed in CSC-enriched populations of human oral squamous cell carcinoma (OSCC) cell lines. Moreover, immunohistochemical staining revealed significantly high level of JMJD6 in OSCC tissues compared to normal human oral epithelia, suggesting that expression of JMJD6 positively correlates with oral carcinogenesis. Subsequent functional analysis showed that knockdown of endogenous JMJD6 in OSCC strongly suppressed self-renewal capacity, a key characteristic of CSCs, and anchorage-independent growth. Conversely, ectopic expression of JMJD6 enhanced CSC characteristics including self-renewal, ALDH1 activity, migration/invasion and drug resistance. Expression of CSC-related genes was also markedly affected by modulating JMJD6 expression. Mechanistically, JMJD6 induces interleukin 4 (IL4) transcription by binding to its promoter region. IL4 rescues self-renewal capacity in JMJD6- knocked down OSCC cells, suggesting the importance of JMJD6-IL4 axis in oral CSCs. Our studies identify JMJD6 as a molecular determinant of CSC phenotype, suggesting that inhibition of JMJD6 may offer an effective therapeutic modality against oral cancer.

miR-135b inhibits tumour metastasis in prostate cancer by targeting STAT6

MicroRNAs (miRNAs) are small non-coding RNAs that participate in several cellular functions and tumour progression. A previous microarray study demonstrated that miR-135b is downregulated in prostate cancer (PCa) cells, but the role and molecular mechanism of miR-135b in the regulation of tumour metastasis remain to be elucidated. In the present study, significant downregulation of miR-135b in PCa tissues, compared with noncancerous tissues, was detected by reverse transcription-quantitative polymerase chain reaction. Furthermore, the expression of miR-135b was demonstrated to be associated with the pathological stage and the levels of total and free prostate-specific antigen (PSA) in PCa cells. In addition, signal transducer and activator of transcription 6 (STAT6) was identified as a target of miR-135b in PCa cells by luciferase activity and western blot assays. The upregulation of miR-135b in PCa cells led to reduced expression of STAT6 in the cytoplasm and nucleus of these cells, while the overexpression of miR-135b and knockdown of STAT6 were able to inhibit the migration and invasion abilities of PCa cells in vitro. Therefore, the results of the present study indicate that miR-135b suppresses tumour metastasis by targeting STAT6.

The potential anti-proliferative effect of β-sitosterol on human mast cell line-1 cells

Thymic stromal lymphopoietin (TSLP) was reported to induce mast cell proliferation and aggravate allergic reactions through activation of mouse double minute 2 (MDM2). We aimed to ascertain that β-sitosterol (SI), which is one of the several phytosterols found mostly in foods, would regulate TSLP-induced mast cell proliferation. The results showed that SI significantly decreased the proliferation of human mast cell line (HMC-1) cells promoted by TSLP. SI significantly decreased the mRNA expression of Ki-67 in the TSLP-treated HMC-1 cells. SI significantly suppressed the production and mRNA expression of interleukin-13 in the TSLP-treated HMC-1 cells. Furthermore, SI downregulated the expression of MDM2 and phosphorylation of STAT6, whereas it upregulated the expression of p53, activation of caspase-3, and cleavage of poly ADP-ribose polymerase in the TSLP-treated HMC-1 cells. Results of this study suggest that SI may be a potential therapeutic agent for mast cell-mediated allergic diseases.

Interleukin-4 receptor-targeted liposomal doxorubicin as a model for enhancing cellular uptake and antitumor efficacy in murine colorectal cancer

Our previous studies showed that colorectal tumor has high interleukin-4 receptor α (IL-4Rα) expression, whereas adjacent normal tissue has low or no IL-4Rα expression. We also observed that human atherosclerotic plaque-specific peptide-1 (AP1) can specifically target to IL-4Rα. In this study, we investigated the therapeutic efficacy and systemic toxicity of AP1-conjuagted liposomal doxorubicin. AP1 bound more strongly to and was more efficiently internalized into IL-4Rα-overexpressing CT26 cells than CT26 control cells. Selective cytotoxicity experiment revealed that AP1-conjugated liposomal doxorubicin preferentially killed IL-4Rα-overexpressing CT26 cells. AP1-conjugated liposomal doxorubicin administered intravenously into mice produced significant inhibition of tumor growth and showed decreased cardiotoxicity of doxorubicin. These results indicated that AP1-conjugated liposomal doxorubicin has a potent and selective anticancer potential against IL-4Rα-overexpressing colorectal cancer cells, thus providing a model for targeted anticancer therapy.

MicroRNA‑361‑5p suppresses cancer progression by targeting signal transducer and activator of transcription 6 in non‑small cell lung cancer

The incidence of non‑small cell lung cancer (NSCLC) has significantly increased in China, while the prognosis of affected patients is poor. The pathogenesis of NSCLC is thought to be regulated by microRNAs (miRs). The present study used a miR array in order to determine the expression of miR‑361‑5p, which was significantly lower in NSCLC tissues compared with that in adjacent tissues, indicating a crucial role of miR‑361‑5p during the progression of NSCLC. Furthermore, the effects of transfection-induced upregulation of miR‑361‑5p on the NSCLC cell line H23 were assessed. Overexpression of miR‑361‑5p inhibited the proliferation and colony formation ability of H23 cells. In addition, apoptosis of H23 cells was induced by upregulation of miR‑361‑5p. Furthermore, signal transducer and activator of transcription 6 (STAT6) was confirmed as a direct target of miR‑361‑5p by a dual‑luciferase reporter assay. Moreover, inhibition of STAT6 by small interfering RNA or miR‑361‑5p also decreased the expression of B-cell lymphoma extra large (Bcl-xL). In vivo, miR‑361‑5p significantly reduced tumor growth in a nude mouse xenograft model, and suppressed STAT6 and Bcl-xL expression. In conclusion, the present study indicated that miR‑361‑5p may represent a novel molecular tool for therapeutic and diagnostic strategies in NSCLC.

Targeting IL4/IL4R for the treatment of epithelial cancer metastasis

While progress has been made in treating primary epithelial tumors, metastatic tumors remain largely incurable and still account for 85-90 % of all cancer-related deaths. Interleukin-4 (IL4), a Th2 cytokine, and the IL4/IL4 receptor (IL4R) interaction have well defined roles in the immune system. Yet, IL4 receptors are over-expressed by many epithelial cancers and could be a promising target for metastatic tumor therapy. The IL4/IL4R signaling axis is a strong promoter of pro-metastatic phenotypes in epithelial cancer cells including enhanced migration, invasion, survival, and proliferation. The promotion of breast cancer growth specifically is also supported in part by IL4-induced glutamine metabolism, and we have shown that IL4 is also capable of inducing glucose metabolism in breast cancer cells. Importantly, there are several types of FDA approved medications for use in asthma patients that inhibit the IL4/IL4R signaling axis. However, these approved medications inhibit both the type I IL4 receptor found on immune cells, and the type II IL4 receptor that is predominantly expressed by some non-hematopoietic cells including epithelial cancer cells. This article reviews existing therapies targeting IL4, IL4R, or IL4/IL4R signaling, and recent findings guiding the creation of novel therapies that specifically inhibit the type II IL4R, while taking into consideration effects on immune cells within the tumor microenvironment. Some of these therapies are currently in clinical trials for cancer patients, and may be exploitable for the treatment of metastatic disease.

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.

IL4 receptor ILR4α regulates metastatic colonization by mammary tumors through multiple signaling pathways

IL4, a cytokine produced mainly by immune cells, may promote the growth of epithelial tumors by mediating increased proliferation and survival. Here, we show that the type II IL4 receptor (IL4R) is expressed and activated in human breast cancer and mouse models of breast cancer. In metastatic mouse breast cancer cells, RNAi-mediated silencing of IL4Rα, a component of the IL4R, was sufficient to attenuate growth at metastatic sites. Similar results were obtained with control tumor cells in IL4-deficient mice. Decreased metastatic capacity of IL4Rα "knockdown" cells was attributed, in part, to reductions in proliferation and survival of breast cancer cells. In addition, we observed an overall increase in immune infiltrates within IL4Rα knockdown tumors, indicating that enhanced clearance of knockdown tumor cells could also contribute to the reduction in knockdown tumor size. Pharmacologic investigations suggested that IL4-induced cancer cell colonization was mediated, in part, by activation of Erk1/2, Akt, and mTOR. Reduced levels of pAkt and pErk1/2 in IL4Rα knockdown tumor metastases were associated with limited outgrowth, supporting roles for Akt and Erk activation in mediating the tumor-promoting effects of IL4Rα. Collectively, our results offer a preclinical proof-of-concept for targeting IL4/IL4Rα signaling as a therapeutic strategy to limit breast cancer metastasis.

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.

Interleukin-4 induces senescence in human renal carcinoma cell lines through STAT6 and p38 MAPK

Interleukin (IL)-4, originally identified as a lymphocyte growth factor, can directly inhibit growth of certain tumor cell types. We reported previously that IL-4 induced cell cycle arrest in G1 phase through an increase in p21(WAF1/CIP1) expression in human renal cell carcinoma (RCC) cell lines. In the present study, we investigated the underlying mechanism of IL-4-induced growth inhibition. In four of six human RCC cell lines, including Caki-1, A498, SNU482, and SNU228, IL-4 induced cellular senescence as demonstrated by enlarged and flattened morphology, increased granularity, and senescence-associated-β-galactosidase (SA-β-gal) staining. Signal tranducer and activator of transcription 6 (STAT6) and p38 MAPK were found to mediate IL-4-induced growth inhibition and cellular senescence. Both of these molecules were activated by 10 min after IL-4 treatment, and inhibition of their activity or expression prevented growth suppression and cellular senescence induced by IL-4. Inhibiting or silencing either STAT6 or p38 MAPK alone partially reduced the effect of IL-4, whereas inhibiting or silencing both molecules exerted an additive effect and almost completely abrogated the effect of IL-4. Thus STAT6 and p38 MAPK appeared to independently mediate IL-4-induced growth inhibition and cellular senescence. The p21(WAF1/CIP1) up-regulation that accompanied growth inhibition and cellular senescence by IL-4 was also attenuated additively when p38 MAPK and STAT6 were silenced. Taken together, these results show that IL-4 induces cellular senescence through independent signaling pathways involving STAT6 and p38 MAPK in some human RCC cell lines.

High expression of IL-13 receptor α2 in colorectal cancer is associated with invasion, liver metastasis, and poor prognosis

Autocrine secretion of cytokines by metastatic colorectal cancer cells and their role during invasion and liver homing has been poorly characterized. In this study, we used cytokine arrays to analyze the secretomes of poorly and highly metastatic colorectal cancer cells. Compared with poorly metastatic cancer cells, highly metastatic cells expressed increased levels of the immunosuppressive cytokines interleukin (IL)-4 and IL-13 in addition to increased surface expression of the high affinity IL-13 receptor IL-13Rα2, suggesting that IL-13Rα2 mediates IL-13 effects in colorectal cancer cells. Silencing of IL-13Rα2 in highly metastatic cells led to a decrease in adhesion capacity in vitro and a reduction in liver homing and increased survival in vivo, revealing a role for this receptor in cell adhesion, migration, invasion, and metastatic colonization. In support of this, IL-13 signaling activated the oncogenic signaling molecules phosphoinositide 3-kinase, AKT, and SRC in highly metastatic cells. Clinically, high expression of IL-13Rα2 was associated with later stages of disease progression and poor outcome in patients with colorectal cancer. Our findings therefore support a critical role for IL-13Rα2 expression in colon cancer invasion and metastasis.

Astrocytes, but not microglia, rapidly sense H₂O₂via STAT6 phosphorylation, resulting in cyclooxygenase-2 expression and prostaglandin release

Emerging evidence has established that astrocytes, once considered passive supporting cells that maintained extracellular ion levels and served as a component of the blood-brain barrier, play active regulatory roles during neurogenesis and in brain pathology. In the current study, we demonstrated that astrocytes sense H(2)O(2) by rapidly phosphorylating the transcription factor STAT6, a response not observed in microglia. STAT6 phosphorylation was induced by generators of other reactive oxygen species (ROS) and reactive nitrogen species, as well as in the reoxygenation phase of hypoxia/reoxygenation, during which ROS are generated. Src-JAK pathways mediated STAT6 phosphorylation upstream. Experiments using lipid raft disruptors and analyses of detergent-fractionated cells demonstrated that H(2)O(2)-induced STAT6 phosphorylation occurred in lipid rafts. Under experimental conditions in which H(2)O(2) did not affect astrocyte viability, H(2)O(2)-induced STAT6 phosphorylation resulted in STAT6-dependent cyclooxygenase-2 expression and subsequent release of PGE(2) and prostacyclin, an effect also observed in hypoxia/reoxygenation. Finally, PGs released from H(2)O(2)-stimulated astrocytes inhibited microglial TNF-α expression. Accordingly, our results indicate that ROS-induced STAT6 phosphorylation in astrocytes can modulate the functions of neighboring cells, including microglia, through cyclooxygenase-2 induction and subsequent release of PGs. Differences in the sensitivity of STAT6 in astrocytes (highly sensitive) and microglia (insensitive) to phosphorylation following brief exposure to H(2)O(2) suggest that astrocytes can act as sentinels for certain stimuli, including H(2)O(2) and ROS, refining the canonical notion that microglia are the first line of defense against external stimuli.

5-Fluorouracil-loaded poly(ε-caprolactone) nanoparticles combined with phage E gene therapy as a new strategy against colon cancer

This work aimed to develop a new therapeutic approach to increase the efficacy of 5-fluorouracil (5-FU) in the treatment of advanced or recurrent colon cancer. 5-FU-loaded biodegradable poly(ε-caprolactone) nanoparticles (PCL NPs) were combined with the cytotoxic suicide gene E (combined therapy). The SW480 human cancer cell line was used to assay the combined therapeutic strategy. This cell line was established from a primary adenocarcinoma of the colon and is characterized by an intrinsically high resistance to apoptosis that correlates with its resistance to 5-FU. 5-FU was absorbed into the matrix of the PCL NPs during synthesis using the interfacial polymer disposition method. The antitumor activity of gene E from the phage ϕX174 was tested by generating a stable clone (SW480/12/E). In addition, the localization of E protein and its activity in mitochondria were analyzed. We found that the incorporation of 5-FU into PCL NPs (which show no cytotoxicity alone), significantly improved the drug's anticancer activity, reducing the proliferation rate of colon cancer cells by up to 40-fold when compared with the nonincorporated drug alone. Furthermore, E gene expression sensitized colon cancer cells to the cytotoxic action of the 5-FU-based nanomedicine. Our findings demonstrate that despite the inherent resistance of SW480 to apoptosis, E gene activity is mediated by an apoptotic phenomenon that includes modulation of caspase-9 and caspase-3 expression and intense mitochondrial damage. Finally, a strongly synergistic antiproliferative effect was observed in colon cancer cells when E gene expression was combined with the activity of the 5-FU-loaded PCL NPs, thereby indicating the potential therapeutic value of the combined therapy.

Clinical investigation of the role of interleukin-4 and interleukin-13 in the evolution of prostate cancer

Prostate cancer is the most common cancer in men, both in the USA and Europe. Although incurable, metastatic disease can often be controlled for years with anti-androgen therapy. Once the disease becomes castrate resistant, the median survival is 18 months. There is growing evidence that the immune system, and in particular cytokines, play an important role in prostate cancer immunosurveillance and progression. Here, we have undertaken a clinical investigation of the role of two closely related cytokines, IL-4 and IL-13 in prostate cancer. In the largest series studied to date, we show that serum IL-4, but not IL-13 is significantly elevated in castrate resistant, compared to androgen sensitive disease. Notably however, serum IL-4 levels are also raised in patients with benign prostatic disease. Analysis of benign and malignant prostate tissue demonstrates that the source of IL-4 is epithelial cells rather than infiltrating leukocytes. Together, our data are consistent with a dual role for IL-4 in prostate cancer development. In benign disease, our data add to the evidence that IL-4 serves a protective role. By contrast, the data support a direct role for IL-4 in the progression of prostate cancer from androgen responsive, to advanced castrate-resistant disease.