Regulatory effect of interleukin-4 and interleukin-13 on colon cancer cell adhesion

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.

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.

A Pipeline to Call Multilevel Expression Changes between Cancer and Normal Tissues and Its Applications in Repurposing Drugs Effective for Gastric Cancer

Differential gene analyses on gastric cancer usually focus on expression change of single genes between tumor and adjacent normal tissues. However, besides changes on single genes, there are also coexpression and expression network module changes during the development of gastric cancer. In this study, we proposed a pipeline to investigate various levels of changes between gastric cancer and adjacent normal tissues, which were used to repurpose potential drugs for treating gastric cancer. Specifically, we performed a series of analyses on 242 gastric cancer samples (33-normal, 209-cancer) downloaded from the cancer genome atlas (TCGA), including data quality control, differential gene analysis, gene coexpression network analysis, module function enrichment analysis, differential coexpression analysis, differential pathway analysis, and screening of potential therapeutic drugs. In the end, we discovered some genes and pathways that are significantly different between cancer and adjacent normal tissues (such as the interleukin-4 and interleukin-13 signaling pathway) and screened perturbed genes by 2703 drugs that have a high overlap with the identified differentially expressed genes. Our pipeline might be useful for understanding cancer pathogenesis as well as gastric cancer treatment.

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.

The Association Between Inflammation, Epithelial Mesenchymal Transition and Stemness in Colorectal Carcinoma

Background

Inflammation plays an important albeit dual role in carcinogenesis. Survival studies have highlighted the prognostic significance of peritumorous inflammation. Currently, the theoretical background allows inflammation, epithelial mesenchymal transition (EMT) and the closely associated stem cell differentiation in colorectal carcinoma (CRC) to be linked. However, there is scarce direct morphological evidence.

Purpose and methods

The aim of our study was to investigate the role of inflammation in cancer growth and invasion by analyzing the association between inflammation and known morphological prognostic features of colorectal cancer, EMT, stemness and mismatch repair (MMR) protein expression. The study was designed as a retrospective morphological and immunohistochemical assessment of 553 consecutive cases of surgically treated primary CRC.

Results

There were statistically significant associations between high-grade inflammation and lower pT (p = 0.002), absence of lymph node metastases (p < 0.001) and less frequent lymphatic (p = 0.003), venous (p = 0.017), arterial (p = 0.012), perineural (p = 0.001) and intraneural (p = 0.01) invasion. In contrast, Crohn's like reaction (CLR) by density of lymphoid follicles in the invasive front lacked significant differences in regard to pT, pN, tumor invasion into surrounding structures (blood or lymphatic vessels, nerves), grade or necrosis (all p > 0.05). The expression of E-cadherin, CD44 and MMR proteins yielded no statistically significant associations with peritumorous inflammation by Klintrup-Mäkinen score or the density of lymphoid follicles. Nevertheless, E-cadherin levels were significantly associated with the density of eosinophils (p = 0.007).

Conclusion

High-grade peritumorous inflammation is associated with beneficial morphologic CRC features, including less frequent manifestations of invasion, and is not secondary to tissue damage and necrosis. CLR is not associated with cancer spread by pTN; this finding indirectly suggests an independent role of CLR in carcinogenesis. Further, inflammation by Klintrup-Mäkinen grade and CLR is not dependent on epithelial-mesenchymal transition and stem cell differentiation. Our study highlights the complex associations between inflammation, tumor morphology, EMT, stemness and MMR protein expression in human CRC tissues.

Inflammation and pancreatic cancer: An updated review

Pancreatic cancer is a devastating disease with poor prognosis in the modern era. Inflammatory processes have emerged as key mediators of pancreatic cancer development and progression. Recently, studies have been carried out to investigate the underlying mechanisms that contribute to tumorigenesis induced by inflammation. In this review, the role of inflammation in the initiation and progression of pancreatic cancer is discussed.

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.

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.

Endogenously Expressed IL-4Rα Promotes the Malignant Phenotype of Human Pancreatic Cancer In Vitro and In Vivo

Exogenous interleukin-4 (IL-4) has been demonstrated to affect the growth of different human malignancies including pancreatic cancer cells. The aim of our study was to determine the role of endogenously expressed IL-4-receptor-α-chain (IL-4Rα) in pancreatic cancer cells. IL-4Rα-suppression was achieved by generating Capan-1 cells stably expressing shRNA targeting IL-4Rα. The malignant phenotype was characterized by assessing growth properties, directional and non-directional cell movement in vitro and tumor growth in vivo. Signaling pathways were analyzed upon IL-4 and IL-13 stimulation of wildtype (WT) and control-transfected cells compared to IL-4Rα-knockdown cells. Silencing of IL-4Rα resulted in reduced anchorage-dependent cell growth (p < 0.05) and reduced anchorage-independent colony size (p < 0.001) in vitro. Moreover, cell movement and migration was inhibited. IL-4 and IL-13 stimulation of Capan-1-WT cells induced activation of similar pathways like stimulation with Insulin-like growth factor (IGF)-I. This activation was reduced after IL-4Rα downregulation while IGF-I signaling seemed to be enhanced in knockdown-clones. Importantly, IL-4Rα silencing also significantly suppressed tumor growth in vivo. The present study indicates that endogenously expressed IL-4 and IL-4Rα contribute to the malignant phenotype of pancreatic cancer cells by activating diverse pro-oncogenic signaling pathways. Addressing these pathways may contribute to the treatment of the disease.

IL-13 induces the expression of 11βHSD2 in IL-13Rα2 dependent manner and promotes the malignancy of colorectal cancer

Previous studies had demonstrated that IL-13 and its receptor IL-13Rα2 participated in the process of onset and development of colorectal cancer, however, its detailed mechanism was still unclear. Herein, we demonstrated that IL-13 induced the expression of 11βHSD2 in an IL-13Rα2 dependent manner in colorectal cancer cells. Furthermore, we indicated 11βHSD2 was critical for IL-13 to induce the expression of COX2 and activated Akt, which was essential for IL-13 to promote the colony formation abilities and migration abilities of colorectal cancer cells. Inhibitor of 11βHSD2 glycyrrhizic acid (GA) significantly reduced the liver metastasis of colorectal cancers cells seeded in the Appendix serous of the nude mice. These results provide evidences to reveal the molecular mechanism in the process of colorectal cancer involving IL-13 and its receptor IL-13Rα2, and may provide new therapeutic target for treatment of colorectal cancer.

Expression of COX-2, IL-1β, TNF-α and IL-4 in epithelium of serrated adenoma, adenoma and hyperplastic polyp

INTRODUCTION

Colon polyps and inflammatory process play the key role in neoplasia of colorectal cancer. In recent years there have been many publications on the malignancy of hyperplastic polyp (HP) which according to the WHO classification is a non-neoplastic polyp. The aim of this study is to determine the expression of inflammatory proteins COX-2, IL-1β, TNF-α and IL-4 in the epithelium of colorectal polyps.

MATERIAL AND METHODS

In the study, 144 colorectal polyps were analyzed. The groups of HP, classical (A) and serrated adenomas (SA) and normal mucosa (control) according to histopathological studies were selected. Immunohistochemical examinations Rusing antibodies against COX-2, IL-1β, TNF-α and IL-4 were performed. The expression of analyzed protein was evaluated using modified Remmele-Stegner scale (0-16).

RESULTS

Statistical analysis revealed higher expression of TNF-α (16 ±3.87 vs. 1 ±5.06), IL-1β (12 ±4 vs 8 ±2.72), COX-2 (9 ±2.54 vs. 8 ±3.14) and IL-4 (12 ±3.45 vs. 4 ±3.35) in SA polyps compared to the control (p < 0.001). The HP had an increased level of expression of TNF-α (12 ±3.72 vs. 1 ±5.06, p < 0.005), COX-2 (8.5 ±1.97 vs. 8 ±3.14, p < 0.012) and IL-4 (12 ±3.46 vs. 4 ±3.35, p < 0.001). Significantly higher expression of IL-4 (12 ±2.32 vs. 4 ±3.35, p < 0.001) and IL-1β (16 ±4.32 vs. 8 ±2.72, p < 0.044) in A compared to the control were observed.

CONCLUSIONS

Expression of inflammatory factors differed between polyps. Inflammation accompanied the serrated structures which occur in polyps. The inflammatory process affects the development of colorectal polyps. The HP may predispose to malignancy.

Salivary Immunosuppressive Cytokines IL-10 and IL-13 Are Significantly Elevated in Oral Squamous Cell Carcinoma Patients

Oral squamous cell carcinoma (OSCC) is considered to be one of the most fatal diseases worldwide, owing to its late diagnosis and lack of availability of established reliable biomarkers. The aim of this study was to highlight the significance of immunosuppressive cytokines as potential biomarkers in OSCC. Whole unstimulated saliva was collected from each individual (30 OSCC patients and 33 age- and gender-matched healthy controls). Immunosuppressive cytokines, including IL-4, IL-10, IL-13, and IL-1RA, were evaluated in each sample using Luminex multianalyte profiling (xMAP) technology on BioPlex instrument. Our results showed that all the studied salivary cytokines were raised in OSCC patients as compared to controls, where IL-10 and IL-13 salivary levels showed statistically significant difference (p = .004 and p = .010, respectively). Mean levels of salivary cytokines in three histologically defined OSCC categories, compared employing one-way ANOVA, showed that salivary levels of IL-1RA were highest in patients having poorly differentiated OSCC tumors as compared to those having moderately and well-differentiated tumors (p = .000 and p = .002, respectively). Among OSCC individuals, duration of smokeless tobacco correlated positively with IL-1RA (p = .036). We conclude that salivary levels of immunosuppressive cytokines, IL-4, IL-10, IL-13, and IL-1RA, could prove to be potential biomarkers of OSCC and can be further investigated as markers of early detection and disease progression.

Interleukin-13 and its receptors in colorectal cancer (Review)

Interleukin (IL)-13 is an immunoregulatory cytokine secreted by numerous immune cells. Its functions are similar to those of IL-4 and they share a common receptor. This cytokine has been included in recent studies on human tumors and malignant diseases, evoking a scientific interest to investigate the role of IL-13 and its receptors as novel biomarkers and targets for therapy. Colorectal cancer is one of the most common human malignancies, its prognosis is not promising and the efficacy of molecular-targeted therapy has not been established. This review summarizes the currently available data on the role of IL-13 and its receptors in colorectal cancer, including the signaling pathways involved in mediating the effects of IL-13, the role of IL-13 and/or its receptors in the prediction of cancer and several drugs targeting IL-13 or its receptors that are currently under evaluation.

Expression of interleukin-4 and interleukin-13 and their receptors in colorectal cancer

PURPOSE

Interleukin-4 (IL-4) and interleukin-13 (IL-13) are anti-inflammatory and immunomodulatory cytokines which can influence cancer-directed immunosurveillance. Nothing is presently known about expression of these cytokines and their receptors (IL-4R and IL-13R) in colorectal cancer. The aim of this study was to characterize their expression in primary colorectal cancer specimens and to evaluate possible functions for this disease.

METHODS

Expression of IL-4, IL-13, IL-4R, and IL-13R protein was characterized by immunohistochemistry in 359 patients with Union for International Cancer Control stage I-III colorectal cancer and evaluated by uni- and multivariate analysis for their prognostic relevance.

RESULTS

All four proteins were expressed in colorectal cancer specimens. In the cancer cells, high IL-4, IL-13, IL-4R, and IL-13R immunoreactivity were present in 33 % (118/359), 50 % (181/359), 36 % (129/359), and 42 % (152/359), respectively. Patients with high expression of IL-4, IL-4R, and IL-13R had a lower frequency of lymph node metastases. Expression of IL-13 did not influence the frequency of lymph node metastases. However, high IL-13-immunoreactivity was associated with a better overall survival (p = 0.041). Expression of IL-4, IL-4R, or IL-13R did not influence survival. Multivariate analysis revealed that besides pT classification and tumor recurrence, IL-13 expression was an independent prognostic factor for overall survival.

CONCLUSIONS

Expression of IL-4, IL-4R, and IL-13R are involved in the process of local metastases in colorectal cancer, while IL-13 expression has an impact on survival. These interleukins and their receptors may become attractive targets for the treatment of colorectal cancer.

The lL-8 and IL-13 gene polymorphisms in inflammatory bowel disease and colorectal cancer

Inflammatory bowel diseases (IBD) and colorectal cancer (CRC) are disorders that originate from immune disturbances. In our study, we evaluated the association between the -251 T/A interleukin (IL)-8 and the -1112 C/T IL-13 polymorphisms, the risk of IBD, and CRC development. Genotypes were determined by PCR-restriction fragment length polymorphism in 191 patients with CRC, 150 subjects with IBD, and 205 healthy controls. We found an association between CRC and the presence of the -251 TA genotype and A allele of the IL-8 gene (odds ratios [ORs] 2.28 and 1.65). A similar relationship was observed between these polymorphic variants and ulcerative colitis (OR 2.05 for the -251 TA genotype and OR 1.47 for the -251 A allele) as well as Crohn's disease (ORs 3.11 and 1.56, respectively). Our research also revealed that the CT and TT genotypes of the IL-13 -1112 C/T polymorphism may be connected with a higher risk of CRC (ORs 2.28 and 1.65). The same genotypes affected the susceptibility of IBD (ORs 2.26 and 3.72). Our data showed that the IL-8 -251 T/A and IL-13 -1112 C/T polymorphisms might be associated with the IBD and CRC occurrence and might be used as predictive factors of these diseases in a Polish population.

Duodenal helminth infection alters barrier function of the colonic epithelium via adaptive immune activation

Chronic infection with intestinal helminth parasites is a major public health problem, particularly in the developing world, and can have significant effects on host physiology and the immune response to other enteric infections and antigens. The mechanisms underlying these effects are not well understood. In the current study, we investigated the impact of infection with the murine nematode parasite Heligmosomoides polygyrus, which resides in the duodenum, on epithelial barrier function in the colon. We found that H. polygyrus infection produced a significant increase in colonic epithelial permeability, as evidenced by detection of elevated serum levels of the tracer horseradish peroxidase following rectal administration. This loss of normal barrier function was associated with clear ultrastructural changes in the tight junctions of colonic epithelial cells and an alteration in the expression and distribution of the junctional protein E-cadherin. These parasite-induced abnormalities were not observed in SCID mice but did occur in SCID mice that were adoptively transferred with wild-type T cells, indicating a requirement for adaptive immunity. Furthermore, the helminth-induced increase in gut permeability was not seen in STAT6 knockout (KO) mice. Taken together, the results demonstrate that one of the mechanisms by which helminths exert their effects involves the lymphocyte- and STAT6-dependent breakdown of the intestinal epithelial barrier. This increase in epithelial permeability may facilitate the movement of lumenal contents across the mucosa, thus helping to explain how helminth infection can alter the immune response to enteric antigens.

Elevated IL-13Ralpha2 in intestinal epithelial cells from ulcerative colitis or colorectal cancer initiates MAPK pathway

BACKGROUND

Chronic inflammation in ulcerative colitis (UC) is a sizeable risk factor for colorectal cancer (CRC). Interleukin-13 (IL-13) is elevated in the UC mucosa and may induce dysregulated signaling in neighboring intestinal epithelial cells (IECs) and thus function as a tumorogenic cytokine.

METHODS

Expression of IL-13 receptor chains on IECs obtained from control or chronically inflamed mucosa and colonic tumors was quantified by flow cytometry and immunoblot. IL-13Ralpha1 and IL-13Ralpha2 expression was significantly increased on IEC from UC and CRC patients compared to control and Crohn's disease (CD) subjects. Purified IEC from these subjects and cell lines expressing varying ratios of IL-13Ralpha1 and IL-13Ralpha2 chains were stimulated with IL-13 in vitro to investigate by immunoblot the activation of the signal transducer and activator of transcription 6 (STAT6) and mitogen activated protein kinase (MAPK) signaling pathways.

RESULTS

Despite similarly elevated receptor expression in UC and CRC, IL-13 does not activate the STAT6 or MAPK pathways in UC, while in colonic tumors only the STAT6 pathway is activated. Using neutralizing antibodies and cell lines expressing a range of surface densities for IL-13Ralpha1 and IL-3Ralpha2, we demonstrate that IL-13Ralpha2 serves a dual role, initiating MAPK signaling at low concentrations and as an inhibitory, decoy receptor at high IL-13Ralpha2 to IL-13Ralpha1 ratios.

CONCLUSIONS

IL-13Ralpha2 is both a decoy receptor and induces MAPK signal transduction, depending on its relative expression and the local concentration of IL-13, which together modulate the balance and intensity of the signaling pathways initiated in UC and CRC.

Epithelial interleukin-4 receptor expression promotes colon tumor growth

Inflammatory mediators are of considerable interest as potential therapeutic targets in various cancers. Here we investigate whether interleukin (IL)-4 receptor alpha (IL4Ralpha), a component of the receptor complex for the T helper 2 cytokines IL4 and IL13, plays a role in colonic tumorigenesis. IL4Ralpha protein expression was seen in tumor cells of 28/48 human colon adenocarcinomas on a tissue microarray. In human and murine colon tumor cell lines analyzed in vitro, all of which expressed IL4Ralpha, treatment with exogenous ligand resulted in dose-dependent increases in proliferation. IL4 decreased apoptosis only in HCT116 cells. An orthotopic allograft model was used to determine in vivo effects of tumor cell-specific IL4Ra ablation. MC38 murine tumor cells with the IL4Ra gene knocked down showed reduced proliferation but no difference in apoptosis compared with controls after implantation in ceca of syngeneic mice. Mice null for IL4Ra and wild-type controls were treated with azoxymethane and dextran sulfate sodium to induce tumor formation. Mice with global deletion of IL4Ra had significantly fewer and smaller tumors. Reduced tumorigenicity correlated with decreased proliferation and increased apoptosis. Systemic blockade of IL4Ralpha-IL4 interactions with a chimeric soluble receptor protein gave similar results in the cecal implant model. Thus, IL4Ralpha, a component of the IL4R and IL13R, contributes to tumor formation in a mouse model of colitis-associated cancer. Proliferation appears to be directly mediated via IL4Ralpha on the epithelial tumor cells. Survival may be an indirect response mediated via other host cells. Our results support therapeutic targeting of IL4Ralpha in colon cancer.

Genetic copy number alterations and IL-13 expression differences in papillary thyroid cancers and benign nodules

Thyroid nodules were the extremely common endocrine tumors, in which papillary thyroid carcinomas (PTCs) were the most prevalent endocrine malignancy, representing 80-90% of all thyroid malignancies. It was still a dilemma to discriminate PTCs and benign thyroid nodules. With a new molecular genetics technology of Multiplex ligation-dependent probe amplification (MLPA), we investigated 13 PTC and 14 benign nodule tissue samples. The results showed that PTCs had more genetic copy number alteration than benign nodules (P < 0.001). Receiver operating characteristic (ROC) curve analysis suggested that genomic aberrations would provide a moderate accuracy method to discriminate PTCs and benign nodules. The gain of interleukin 13 (IL-13) gene obviously identified the great difference between PTCs and benign nodules. Immunohistochemistry also confirmed significantly higher IL-13 expression in the PTCs (P < 0.001). The current study showed that MLPA should be an effective method to diagnose PTCs and benign thyroid nodules, and also provided a clue to another relationship between IL-13 and PTCs.

Lymphocyte recruitment into the tumor site is altered in patients with MSI-H colon cancer

The ability of the host to mount an appropriate immune response to aberrant cells is one factor that determines prognosis in cancer patients. Naturally occurring regulatory T cells (T regs; CD4+ CD25+ cells) are key regulators of peripheral tolerance. It has been suggested that high levels of T regs are detrimental to the patient in some forms of cancer, but the role of these antigen-specific cells in individuals with colorectal cancers with high levels of microsatellite instability is unknown. Herein, we examined the ability of individuals with MSI-H or microsatellite stable colon cancer to recruit lymphocytes to the tumor site. Immunohistochemical staining was performed on archived paraffin-embedded specimens from a total of 38 individuals with MSI-H (n = 25) or MSS (n = 13) colon cancers to determine the proportion of CD3+, CD8+ and CD25+ cells infiltrating the tumor site. Patients with MSI-H colon cancers had increased percentages of CD8+ TILs (cytotoxic T cells) as compared to individuals with MSS colon cancer (47.3 vs. 24.04% of the infiltrate CD8+, respectively). No differences in the levels of CD25+ T cells were observed between individuals with MSI-H colon cancers and MSS colon cancers (0.53 vs. 0.54% CD25+, respectively). Together, these data suggest that the survival advantage enjoyed by patients with MSI-H colorectal cancer may, in part, be attributed to the increased cytolytic response, but not to an antigen-specific immunosuppressive response in MSS patients.

Interleukin-13 exerts autocrine growth-promoting effects on human pancreatic cancer, and its expression correlates with a propensity for lymph node metastases

BACKGROUND AND AIMS

Interleukin-13 (IL-13) is an anti-inflammatory cytokine produced in cells of hematopoetic origin. It is not known whether pancreatic cancer cells produce IL-13 or whether IL-13 can modulate pancreatic cancer cell growth and influence the frequency of lymph node metastases.

MATERIALS AND METHODS

Cell growth and signaling were analyzed by cell counting, colorimetric proliferation assays, fluorescent-activated cell sorting, and in vitro kinase activity assays. IL-13 expression and secretion were determined by Northern blot analysis and enzyme-linked immunosorbent assay, respectively. Localization of IL-13 and its transmembrane receptor (IL-4R) in primary pancreatic ductal adenocarcinoma (PDAC) was characterized by immunohistochemistry.

RESULTS

IL-13 enhanced the growth of ASPC-1, CAPAN-1, and COLO-357 cells. This was associated with enhanced p44/42 mitogen-activated protein kinase (MAPK) phoshorylation. In contrast to p44/42 MAPK, phosphatidylinositol 3-kinase activity was also induced in IL-13-unresponsive MIA PaCa-2, PANC-1, and T3M4 cells. All cells expressed and secreted IL-13. Neutralizing IL-13 antibodies inhibited the growth of ASPC-1 and CAPAN-1 cells. Immunohistochemical analysis of resected primary ductal adenocarcinoma specimens revealed high levels of IL-13 in 30 of 70 cases and its transmembrane receptor (IL-4R) in 28 of 70 cases, respectively. Fifteen of 16 specimens (94%) exhibiting high IL-13 and IL-4R coexpression had lymph node metastases, while only 30 of the remaining 54 samples (56%) had positive lymph nodes (p = 0.0134).

CONCLUSION

IL-13 can act as an autocrine growth factor in PDAC. Endogenous expression of IL-13 in conjunction with IL-4R in the cancer cells seems to facilitate lymph node metastasis.

Lack of interleukin-4 receptor alpha chain-dependent signalling promotes azoxymethane-induced colorectal aberrant crypt focus formation in Balb/c mice

Interleukin (IL)-4 receptor (IL-4R) alpha chain-dependent signalling by IL-4 and IL-13 promotes tumour growth and metastasis in mouse models of colorectal cancer. However, the role of IL-4R alpha-dependent signalling during the early, pre-malignant stages of colorectal carcinogenesis has not been investigated. Therefore, we investigated the effect of deletion of the IL-4R alpha gene on azoxymethane-induced colorectal aberrant crypt focus (ACF) multiplicity and size in Balb/c mice. IL-4R alpha(-/-) mice developed significantly more ACFs [median 8, inter-quartile range (IQR) 4-11.5; n = 9] than wild-type (WT) animals (median 4, IQR 1-6; n = 9; p = 0.04, Mann-Whitney U-test). There were significantly higher levels of IL-4 in serum from azoxymethane- and sham-treated IL-4R alpha(-/-) mice than WT animals, but no difference in serum IL-13 levels. In the absence of functional IL-4Rs, IL-13 can also signal via the IL-13R alpha2 receptor, leading to induction of transforming growth factor (TGF) beta, which has pro-tumourigenic activity at early stages of intestinal tumourigenesis. We found that mucosal TGFbeta mRNA levels and intestinal epithelial cell TGFbeta immunoreactivity were significantly higher in IL-4R alpha(-/-) mice than in WT animals. In summary, IL-4R alpha-dependent signalling has a protective, anti-neoplastic role during the post-initiation phase of azoxymethane-induced colorectal carcinogenesis in Balb/c mice. Our data should prompt thorough investigation of the role of IL-4R alpha-dependent signalling during human colorectal carcinogenesis, particularly as antagonism of IL-4R signalling represents a therapeutic strategy for asthma and other allergic diseases.

Inflammatory cell infiltration of tumors: Jekyll or Hyde

Inflammatory cell infiltration of tumors contributes either positively or negatively to tumor invasion, growth, metastasis, and patient outcomes, creating a Dr. Jekyll or Mr. Hyde conundrum when examining mechanisms of action. This is due to tumor heterogeneity and the diversity of the inflammatory cell phenotypes that infiltrate primary and metastatic lesions. Tumor infiltration by macrophages is generally associated with neoangiogenesis and negative outcomes, whereas dendritic cell (DC) infiltration is typically associated with a positive clinical outcome in association with their ability to present tumor antigens (Ags) and induce Ag-specific T cell responses. Myeloid-derived suppressor cells (MDSCs) also infiltrate tumors, inhibiting immune responses and facilitating tumor growth and metastasis. In contrast, T cell infiltration of tumors provides a positive prognostic surrogate, although subset analyses suggest that not all infiltrating T cells predict a positive outcome. In general, infiltration by CD8(+) T cells predicts a positive outcome, while CD4(+) cells predict a negative outcome. Therefore, the analysis of cellular phenotypes and potentially spatial distribution of infiltrating cells are critical for an accurate assessment of outcome. Similarly, cellular infiltration of metastatic foci is also a critical parameter for inducing therapeutic responses, as well as establishing tumor dormancy. Current strategies for cellular, gene, and molecular therapies are focused on the manipulation of infiltrating cellular populations. Within this review, we discuss the role of tumor infiltrating, myeloid-monocytic cells, and T lymphocytes, as well as their potential for tumor control, immunosuppression, and facilitation of metastasis.

A systemic antitumor immune response prevents outgrowth of lung tumors after i.v. rechallenge but is not able to prevent growth of experimental liver tumors

Although a systemic antitumor immune response by antibodies or T cells is often detected in cancer patients, this response mostly does not result in tumor rejection. The beneficial effect of tumor vaccination on survival rates is limited as tumor response is low. In contrast to solid tumors, circulating tumor cells may be more easily accessible and therefore destroyed by the immune system and thus prevent metastases. This discrepancy is further clarified in our study, by assessing the effect of a systemic immune response on established liver tumors and circulating tumor cells. Male Wag/Rij rats were inoculated with CC531 colorectal tumor cells subcapsulary in the liver, with or without immune suppression (60 mg/kg cyclophosphamide). To study the effect of a systemic immune response, rats received CC531 tumor cells intravenously and three weeks later the number of lung tumors was assessed. Presence of specific anti-CC531 antibodies in serum was determined by flow cytometric analysis at times of inoculation, i.v. tumor cell administration and sacrifice. Rats with liver tumors and subsequent rechallenge produced anti-CC531 IgG antibodies and did not develop lung tumors, whereas without existing liver tumors, rats developed lung tumors upon i.v. administration of CC531 tumor cells. Liver tumors in rats with and without i.v. CC531 tumor cell administration were equal in size. These results showed that a systemic immune response, induced upon liver tumor induction and rechallenge, prevented formation of lung tumors but did not affect tumor growth in the liver. Possibly the immune response lacked the ability to penetrate the protective extracellular matrix surrounding the established liver tumors, which prevented the tumor cells from recognition by and contact with cells of the immune system.

Role of IL-13 in regulation of anti-tumor immunity and tumor growth

Major mediators of anti-tumor immunity are CD4(+) T(h)1 cells and CD8(+) cytotoxic T lymphocytes (CTLs). In tumor-bearing animals, the T(h)1- and CTL-mediated anti-tumor immunity is down-regulated in multiple ways. Better understanding of negative regulatory pathways of tumor immunity is crucial for the development of anti-tumor vaccines and immunotherapies. Since immune deviation toward T(h)2 suppresses T(h)1 development, it has been thought that induction affecting a T(h)2 immune response is one of the mechanisms that down-regulate effective tumor immune responses. Recent studies using T(h)2-deficient signal transducer and activator (Stat6) KO mice demonstrated that this hypothesis was the case. IL-13 is one of the T(h)2 cytokines that has very similar features to IL-4 through sharing some receptor components and Stat6 signal transduction. It has been thought that IL-13 is not as critical for immune deviation as IL-4 since it cannot directly act on T cells. However, recent studies of IL-13 reveal that this cytokine plays a critical role in many aspects of immune regulation. Studies from our lab and others indicate that IL-13 is central to a novel immunoregulatory pathway in which NKT cells suppress tumor immunosurveillance. Here we will describe biological properties and functions of IL-13, its role in the negative regulation of anti-tumor immunity, and effects of IL-13 on tumor cells themselves.

Coexpression of carcinoembryonic antigen and E-cadherin in colorectal adenocarcinoma with liver metastasis

Carcinoembryonic antigen (CEA) has been suggested as a metastatic activator in colorectal carcinoma, whereas the E-cadherin expression is downregulated in a variety of carcinomas. CEA and E-cadherin expressions were simultaneously assessed with regard to tumor progression in the various sites of colorectal carcinomas with liver metastasis. Twenty-six consecutive patients who had colorectal carcinoma with liver metastasis underwent curative surgery for primary tumor and liver metastasis. CEA and E-cadherin expression were identified on immunohistochemical staining using the labeled streptavidin-biotin method. Their mRNA expression was also detected by RT in situ PCR using one-step reverse transcription-polymerase chain reaction (RT-PCR). CEA and E-cadherin expression scores in the tumor center were greater than those in the tumor margin in both primary tumor and liver metastasis (P<0.001 to 0.006). CEA expression scores were closely associated with E-cadherin expression scores on the corresponding tumor site (P<0.001 to 0.017). CEA and E-cadherin mRNA expression was greatest in the hepatocytes adjacent to liver metastasis, next greatest in the primary tumor, and least in the liver metastasis (P<0.001 to 0.002). CEA mRNA expression was also closely correlated with E-cadherin mRNA expression in the primary tumor (P<0.001) and in the adjacent hepatocytes of the liver metastasis (P=0.018). Patients with a lesser CEA expression score in the liver metastasis margin appeared to have a longer disease-free survival period than did those with a greater CEA expression score. Expression of CEA and E-cadherin was closely correlated with the mRNA levels. Furthermore, these correlations may be implicated in the tumor progression of colorectal carcinoma considering their biological properties.