IL-33 targeting attenuates intestinal mucositis and enhances effective tumor chemotherapy in mice

The involvement of mast cells in the irinotecan-induced enteric neurons loss and reactive gliosis

Background

The irinotecan (CPT-11) causes intestinal mucositis and diarrhea that may be related to changes in the enteric nervous system (ENS). In inflammatory condition, mast cells release a variety of pro-inflammatory mediators that can interact with the ENS cells. It has not been explored whether CPT-11 is able to alter the enteric glial and neuronal cell, and the role of mast cells in this effect. Therefore, this study was conducted to investigate the effect of CPT-11 on the enteric glial and neuronal cells, as well as to study the role of mast cells in the CPT-11-induced intestinal mucositis.

Methods

Intestinal mucositis was induced in Swiss mice by the injection of CPT-11 (60 mg/kg, i.p.) once a day for 4 days following by euthanasia on the fifth day. To investigate the role of mast cells, the mice were pretreated with compound 48/80 for 4 days (first day, 0.6 mg/kg; second day, 1.0 mg/kg; third day, 1.2 mg/kg; fourth day, 2.4 mg/kg) to induce mast cell degranulation before the CPT-11 treatment.

Results

Here, we show that CPT-11 increased glial fibrillary acidic protein (GFAP) and S100β gene and S100β protein expressions and decreased HuC/D protein expression in the small intestine segments. Concomitantly, CPT-11 enhanced tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels and inducible nitric oxide synthase (iNOS) gene expression, associated with an increase in the total number macrophages (positive cells for ionized calcium-binding adapter molecule, Iba-1) and degranulated mast cells in the small intestine segments and caused significant weight loss. The pretreatment with compound 48/80, an inductor of mast cells degranulation, significantly prevented these CPT-11-induced effects.

Conclusions

Our data suggests the participation of mast cells on the CPT-11-induced intestinal mucositis, macrophages activation, enteric reactive gliosis, and neuron loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0854-1) contains supplementary material, which is available to authorized users.

Properdin deficiency protects from 5-fluorouracil-induced small intestinal mucositis in a complement activation-independent, interleukin-10-dependent mechanism

Intestinal mucositis is a serious complication of chemotherapy that leads to significant morbidity that may require dose or drug adjustments. Specific mitigating strategies for mucositis are unavailable, due partly to an incomplete understanding of the pathogenic mechanisms. We have previously shown an effect of properdin, a positive regulator of complement activation, in models of colitis. Here we use properdin-deficient (P^KO ) mice to interrogate the role of properdin and complement in small intestinal mucositis. Mucositis was induced by five daily injections of 5-fluorouracil (5-FU) in wild-type (WT), P^KO , interleukin (IL)-10^-/- and properdin/IL-10^-/- double knock-out (DKO) mice. At the time of euthanasia their jejunum was collected for histology, immunohistochemistry and cytokine and complement activation measurements. Complement became activated in mice receiving 5-FU, indicated by increased intestinal levels of C3a and C5a. Compared to WT, P^KO mice experienced significantly less mucositis, despite C3a levels as high as inflamed WT mice and slightly less C5a. Conversely, P^KO mice had higher intestinal levels of IL-10. IL-10 expression was mainly by epithelial cells in both uninflamed and inflamed P^KO mice. IL-10^-/- mice proved to be highly susceptible to mucositis and DKO mice were equally susceptible, demonstrating that a lack of properdin does not protect mice lacking IL-10. We interpret our findings to indicate that, to a significant extent, the inflammation of mucositis is properdin-dependent but complement activation-independent. Additionally, the benefit achieved in the absence of properdin is associated with increased IL-10 levels, and IL-10 is important in limiting mucositis.

Irinotecan- and 5-fluorouracil-induced intestinal mucositis: insights into pathogenesis and therapeutic perspectives

PURPOSE

Intestinal mucositis and diarrhea are common manifestations of anticancer regimens that include irinotecan, 5-fluorouracil (5-FU), and other cytotoxic drugs. These side effects negatively impact therapeutic outcomes and delay subsequent cycles of chemotherapy, resulting in dose reductions and treatment discontinuation. Here, we aimed to review the experimental evidence regarding possible new targets for the management of irinotecan- and 5-FU-related intestinal mucositis.

METHODS

A literature search was performed using the PubMed and MEDLINE databases. No publication time limit was set for article inclusion.

RESULTS

Here, we found that clinical management of intestinal mucositis and diarrhea is somewhat ineffective at reducing symptoms, possibly due to a lack of specific targets for modulation. We observed that IL-1β contributes to the apoptosis of enterocytes in mucositis induced by 5-FU. However, 5-FU-related mucositis is far less thoroughly investigated with regard to specific molecular targets when compared to irinotecan-related disease. Several studies have proposed that a correlation exists between the intestinal microbiota, the enterohepatic recirculation of active metabolites of irinotecan, and the establishment of mucositis. However, as reviewed here, this association seems to be controversial. In addition, the pathogenesis of irinotecan-induced mucositis appears to be orchestrated by interleukin-1/Toll-like receptor family members, leading to epithelial cell apoptosis.

CONCLUSIONS

IL-1β, IL-18, and IL-33 and the receptors IL-1R, IL-18R, ST2, and TLR-2 are potential therapeutic targets that can be modulated to minimize anticancer agent-associated toxicity, optimize cancer treatment dosing, and improve clinical outcomes. In this context, the pathogenesis of mucositis caused by other anticancer agents should be further investigated.

Exosomes miR-126a released from MDSC induced by DOX treatment promotes lung metastasis

Acquired resistance to chemotherapy remains a major stumbling block in cancer treatment. Chronic inflammation plays a crucial role in induction of chemo resistance, and results in part from the induction and expansion of inflammatory cells that include myeloid derived suppressor cells (MDSC) and IL-13⁺Th2 cells. The mechanisms that lead to induction of activated MDSCs and IL-13⁺Th2 cells have not yet been identified. Here we demonstrated that doxorubicin treatment of 4T1 breast tumor bearing mice led to the induction of IL-13R⁺miR-126a⁺MDSC (DOX-MDSC). DOX-MDSC promote breast tumor lung metastasis through MDSC miR-126a⁺exosomal mediated induction of IL-13⁺Th2 cells and tumor angiogenesis. The induction of DOX-MDSC is regulated in a paracrine manner. DOX treatment not only increases IL-33 released from breast tumor cells, which is crucial for the induction of IL-13⁺Th2 cells, but it also participates in the induction of IL-13 receptors and miR-126a expressed on/in the MDSCs. IL-13 released from IL-13⁺Th2 cells then promotes the production of DOX-MDSC and MDSC miR-126a⁺exosomes via MDSC IL-13R. MDSC miR-126a⁺exosomes further induce IL13⁺Th2 cells in a positive feed-back loop manner. We also showed that MDSC miR-126a rescues doxorubicin induced MDSC death in a S100A8/A9 dependent manner and promotes tumor angiogenesis. Our findings provide insight into the MDSC exosomal mediated chemo resistance mechanism, which will be useful for the design of inhibitors targeting the blocking of induction of miR-126a⁺MDSC.

Programming of Intestinal Epithelial Differentiation by IL-33 Derived from Pericryptal Fibroblasts in Response to Systemic Infection

The intestinal epithelium constitutes an efficient barrier against the microbial flora. Here, we demonstrate an unexpected function of IL-33 as a regulator of epithelial barrier functions. Mice lacking IL-33 showed decreased Paneth cell numbers and lethal systemic infection in response to Salmonella typhimurium. IL-33 was produced upon microbial challenge by a distinct population of pericryptal fibroblasts neighboring the intestinal stem cell niche. IL-33 programmed the differentiation of epithelial progenitors toward secretory IEC including Paneth and goblet cells. Finally, IL-33 suppressed Notch signaling in epithelial cells and induced expression of transcription factors governing differentiation into secretory IEC. In summary, we demonstrate that gut pericryptal fibroblasts release IL-33 to translate bacterial infection into an epithelial response to promote antimicrobial defense.

A novel genetic score model of UGT1A1 and TGFB pathway as predictor of severe irinotecan-related diarrhea in metastatic colorectal cancer patients

PURPOSE

UGT1A1*28/*6 as predictors of severe irinotecan-related diarrhea (SIRD) were duplicated by many studies. However, some patients of lower risk genotype (UGT1A1*1/*1) still suffered SIRD and the extremely low frequency of UGT1A1*6/*6 limited its clinical usage. Previous studies proved that the transforming growth factor (TGFB) family may have some effect on MTX-induced mucositis. However, the associations between TGFB gene variants and SIRD have never been reported so far. Our aim was to improve the predictive value of UGT1A1 gene variants on SIRD.

METHODS

Six SNPs (TGFB1 rs1800469; TGFBR1 rs10733710, rs334354 and rs6478974; TGFBR2 rs3087465; UGT1A1*6) and UGT1A1*28 were selected for genotyping in 160 metastatic colorectal cancer patients treated with irinotecan in a prospective multicenter trial (NCT01282658).

RESULTS

UGT1A1*6, UGT1A1*28, rs1800469 and rs3087465 were all associated with SIRD (p = 0.026, 0.014, 0.047 and 0.045 respectively). A novel genetic score model (with a cut off value of 1.5) based on them was created to predict SIRD (OR = 11.718; 95 % CI 2.489-55.157, p = 0.002). In patients of gene score > 1.5, the risk of SIRD was much higher (23.5 vs. 2.8 %, p = 2.24E-04) and continued in the first 6 cycles of chemotherapy, while in patients with gene score ≤1.5, the risk was much lower and none of them suffered SIRD after the first cycle of chemotherapy (p = 0.0003).

CONCLUSIONS

The novel genetic score model improved the predictive value of UGT1A1 on SIRD. If validated, it will provide valuable information for clinical use of irinotecan.

The PDGF-BB-SOX7 axis-modulated IL-33 in pericytes and stromal cells promotes metastasis through tumour-associated macrophages

Signalling molecules and pathways that mediate crosstalk between various tumour cellular compartments in cancer metastasis remain largely unknown. We report a mechanism of the interaction between perivascular cells and tumour-associated macrophages (TAMs) in promoting metastasis through the IL-33–ST2-dependent pathway in xenograft mouse models of cancer. IL-33 is the highest upregulated gene through activation of SOX7 transcription factor in PDGF-BB-stimulated pericytes. Gain- and loss-of-function experiments validate that IL-33 promotes metastasis through recruitment of TAMs. Pharmacological inhibition of the IL-33–ST2 signalling by a soluble ST2 significantly inhibits TAMs and metastasis. Genetic deletion of host IL-33 in mice also blocks PDGF-BB-induced TAM recruitment and metastasis. These findings shed light on the role of tumour stroma in promoting metastasis and have therapeutic implications for cancer therapy.

Elevated IL-33 levels have been correlated with metastasis and poor prognosis. Here the authors show in mouse tumour xenograft models that PDGF-BB produced by tumour cells induces IL-33 via Sox7 in tumour pericytes, and IL-33 promotes metastasis through its effects on tumour-associated macrophages.

IL-33 promotes growth and liver metastasis of colorectal cancer in mice by remodeling the tumor microenvironment and inducing angiogenesis

Liver metastasis is the major cause of death from colorectal cancer (CRC). Understanding its mechanisms is necessary for timely diagnosis and development of effective therapies. Interleukin-33 (IL-33) is an IL-1 cytokine family member that uniquely functions as a cytokine and nuclear factor. It is released by necrotic epithelial cells and activated innate immune cells, functioning as an alarmin or an early danger signal. Its role in invoking type 2 immune response has been established; however, it has contrasting roles in tumor development and metastasis. We identified IL-33 as a potently upregulated cytokine in a highly metastatic murine CRC cell line and examined its role in tumor growth and metastasis to the liver. IL-33 was transgenically expressed in murine and human adenocarcinoma and carcinoma cell lines and their growth and spontaneous metastasis to the liver were assessed in orthotopic models of CRC in wild-type C57Bl/6 and Il33 knockout mice. The results showed that increased expression of IL-33 in CRC cells enhanced their tumor take, growth, and liver metastasis. Tumor- rather than host-derived IL-33 induced the enhanced recruitment of CD11b⁺ GR1⁺ and CD11b⁺ F4/80⁺ myeloid cells to remodel the tumor microenvironment by increased expression of mobilizing cytokines, and tumor angiogenesis by activating endothelial cells. IL-33 expression was elevated in patient tumor tissues, induced early in adenoma development, and activated by pro-inflammatory cytokines derived from the tumor microenvironment. The data suggest that tumor-derived IL-33 modulates the tumor microenvironment to potently promote colon carcinogenesis and liver metastasis, underscoring its potential as a therapeutic target. © 2016 Wiley Periodicals, Inc.

Potential Therapeutic Aspects of Alarmin Cytokine Interleukin 33 or Its Inhibitors in Various Diseases

PURPOSE

The purpose of this review was to examine the comprehensively accumulated data regarding potential therapeutic aspects of exogenous administration of interleukin 33 (IL-33) or its antagonists in allergic, cancerous, infectious, and inflammatory diseases.

METHODS

A selected review was undertaken of publications that examined the protective and exacerbating effects of IL-33 or its inhibitors in different diseases. Mechanisms of action are summarized to examine the putative role of IL-33 in various diseases.

FINDINGS

IL-33 promoted antibacterial, antiviral, anti-inflammatory, and vaccine adjuvant functions. However, in TH2-biased respiratory, allergic, parasitic, and inflammatory conditions, IL-33 exhibited disease-sensitizing effects. The alarmin cytokine IL-33 induced protective effects in diseases via recruitment of regulatory T cells; antiviral CD8(+) cells, natural killer cells, γδ T cells, and nuocytes; antibacterial and antifungal neutrophils or macrophages; vaccine-associated B/T cells; and inhibition of nuclear factor-κB-mediated gene transcription. In contrast, IL-33 exacerbated the disease process by increasing TH2 cytokines, IgE and eosinophilic immune responses, and inhibition of leukocyte recruitment in various diseases.

IMPLICATIONS

The protective or exacerbated aspects of use of IL-33 or its inhibitors are dependent on the type of infection or inflammatory condition, duration of disease (acute or chronic), organ involved, cytokine microenvironment, dose or kinetics of IL-33, and genetic predisposition. The alarmin cytokine IL-33 acts at cellular, molecular, and transcriptional levels to mediate pluripotent functions in various diseases and has potential therapeutic value to mitigate the disease process.

The reduction of oxidative stress by nanocomposite Fullerol decreases mucositis severity and reverts leukopenia induced by Irinotecan

Irinotecan is a useful chemotherapeutic agent for the treatment of several solid tumors. However, this therapy is associated with side effects, including leukopenia and mucositis. Reactive oxygen species (ROS) activate inflammatory pathways and contribute to Irinotecan-induced mucositis. Fullerol is a nanocomposite with anti-oxidant properties that may reduce tissue damage after inflammatory stimuli. In this paper, the effects of Fullerol and mechanisms of protection were investigated in a model of Irinotecan-induced mucositis. Mucositis was induced by an injection of Irinotecan per 4 days in C57BL/6. Fullerol or a vehicle was injected every 12h. On day 7, the intestines were removed to evaluate histological changes, leukocyte influx, and the production of cytokines and ROS. Irinotecan therapy resulted in weight loss, an increased clinical score and intestinal injury. Treatment with Fullerol attenuated weight loss, decreased clinical score and intestinal damage. Irinotecan also induced increased ROS production in enterocytes, oxidative stress, IL-1β production, neutrophil and eosinophil influx in the ileum. Fullerol treatment decreased production of ROS in the enterocytes, oxidative stress, IL-1β production, neutrophil and eosinophil influx in the ileum. Irinotecan therapy also induced leukopenia in an ROS-dependent manner because leukopenia reverted in WT mice treated with Fullerol or Apocynin or in Gp91phox(-/-) mice. Mice treated with Irinotecan presented less melanoma tumor growth compared to the control group. Fullerol does not interfere in the anti-tumor action of Irinotecan. Fullerol has a great pharmacology potential to decreases the severity of mucositis and of leukopenia during chemotherapy treatment.

Irinotecan (CPT-11)-induced elevation of bile acids potentiates suppression of IL-10 expression

Irinotecan (CPT-11) is a first-line anti-colon cancer drug, however; CPT-11-induced toxicity remains a key factor limiting its clinical application. To search for clues to the mechanism of CPT-11-induced toxicity, metabolomics was applied using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry. Intraperitoneal injection of 50 mg/kg of CPT-11 induced loss of body weight, and intestine toxicity. Changes in gallbladder morphology suggested alterations in bile acid metabolism, as revealed at the molecular level by analysis of the liver, bile, and ileum metabolomes between the vehicle-treated control group and the CPT-11-treated group. Analysis of immune cell populations further showed that CPT-11 treatment significantly decreased the IL-10-producing CD4 T cell frequency in intestinal lamina propria lymphocytes, but not in spleen or mesenteric lymph nodes. In vitro cell culture studies showed that the addition of bile acids deoxycholic acid and taurodeoxycholic acid accelerated the CPT-11-induced suppression of IL-10 secretion by activated CD4(+) naive T cells isolated from mouse splenocytes. These results showed that CPT-11 treatment caused metabolic changes in the composition of bile acids that altered CPT-11-induced suppression of IL-10 expression.

A new animal model of intestinal mucositis induced by the combination of irinotecan and 5-fluorouracil in mice

PURPOSE

Intestinal mucositis (IM) is a common side effect of anticancer agents. Despite polychemotherapy use in clinical practice, the pathogenesis of IM has been investigated in single drug injection animal models. However, the progression of IM could vary according to drug regimens. Thus, we aimed to develop a new experimental mucositis model induced by combining irinotecan and 5-fluorouracil (5-FU) treatments.

METHODS

IM was induced in male C57BL/6 mice by the intraperitoneal administration of either 0.9 % saline (5 mL/kg), irinotecan (IRI, 30 or 45 mg/kg), 5-FU (25, 37.5, or 50 mg/kg), or the combination of these doses (IRI + 5-FU) for 4 days. Animal survival, body mass variation, and diarrhea scores were evaluated daily. On the 7th day, the mice were euthanized, and intestinal samples were collected for histopathology and morphometric analysis, as well as for the determination of myeloperoxidase activity and cytokine dosage (TNF-α and IL-6).

RESULTS

The optimal dose combination that induced IM and presented no substantial mortality on the 7th day was IRI (45 mg/kg) + 5-FU (37.5 mg/kg), which was used for subsequent studies. IRI and 5-FU in combination induced significant diarrhea, body weight loss, intestinal damage, inflammatory cell infiltration, and increased levels of cytokines when compared with other groups (P < 0.05). Neither IRI nor 5-FU alone induced IM.

CONCLUSIONS

We developed a new experimental model of IM induced by combining irinotecan and 5-FU treatments, which will allow us to gain a better knowledge concerning the pathogenesis of this disease through the pharmacological modulation of key inflammatory mediators.

Virus-like particles presenting interleukin-33 molecules: immunization characteristics and potentials of blockingIL-33/ST2 pathway in allergic airway inflammation

We sought to develop an IL-33 vaccine and evaluate its efficacy in a mouse model of asthma. The full-length molecules of putative mature IL-33 were inserted into the immunodominant epitope region of hepatitis B core antigen using gene recombination techniques. The expressed chimeric protein presented as virus-like particles (VLPs) under observation using an electron microscopy. To investigate immunization characteristics of the VLPs, mice were immunized by using different doses, adjuvants, and routes. The VLPs induced sustained and high titers of IL-33-specific IgG and IgA even without the use of a conventional adjuvant, and the lowered ratio of IgG1/IgG2a in vaccinated mice indicated a shift from Th2 to Th1-like responses. To assess the vaccine effects on blocking the signaling of IL-33/ST2 pathway, mice receiving 3 vaccinations subjected to intraperitoneal sensitization and intranasal challenge with ovalbumin (OVA). Control animals received carrier or PBS in place of the vaccine. Immunization with the VLPs significantly suppressed inflammatory cell number and IL-33 level in BALF. OVA -induced goblet cell hyperplasia and lung tissue inflammatory cell infiltration were significantly suppressed in vaccinated mice. Our data indicate that IL-33 molecule-based vaccine, which may block IL-33/ST2 signaling pathway on a persistent basis, holds potential for treatment of asthma and, by extension, other diseases where overexpressed IL-33 plays a pivotal role in pathogenesis.

IL-33/ST2 pathway contributes to metastasis of human colorectal cancer

Interleukin-33 (IL-33) was recently implicated in cancer pathogenesis. However, the possible effect of IL-33 on tumor progression of colorectal cancer (CRC), which is one of the most commonly diagnosed and lethal cancers worldwide, was still unclear. Here we evaluated the potential role of IL-33/ST2 pathway in metastasis of human CRC. We found an elevated expression of IL-33 and ST2 in tumor tissues of CRC patients. Higher expressions of IL-33 and ST2 were observed in poor-differentiated human CRC cells. Of note, IL-33 stimulation promoted the invasion of human CRC cells in a dose dependent manner. Enhanced IL-33/ST2 signaling promoted CRC metastasis, while attenuated IL-33/ST2 signaling decreased CRC metastasis. In consistent, enforced IL-33 expression in human CRC cells enhanced their growth, metastasis and reduced the survival time in nude mice, while decreased IL-33 expression in human CRC cells inhibited their growth, metastasis and prolonged the survival time in nude mice. Finally, we observed an increased expression of IL-6, CXCR4, MMP2 and MMP9 in response to IL-33/ST2 signaling in human CRC cells, which were crucial for the enhanced metastasis by IL-33 stimulation. Collectively, our findings demonstrated that IL-33/ST2 pathway could contribute to the metastasis of human CRC, which could enlarge the understanding of CRC pathogenesis and provide clues for developing new CRC therapeutics.