Interleukin-8 and its receptor CXCR2 in the tumour microenvironment promote colon cancer growth, progression and metastasis

TNF-α increases in the CSF of children with acute lymphoblastic leukemia before CNS relapse

There is scarce information regarding the concentration of cytokines in cerebrospinal fluid (CSF) of children with acute lymphoblastic leukemia (ALL) and their clinical association with CNS status. A prospective analysis of 40 patients <18years with newly diagnosed ALL was performed. Human cytokine magnetic bead panel assay values of IL-2, IL-4, IL-6, IL-8, IL-10, MCP-1, TNF-α in CSF at diagnosis, end of induction to remission, and 6months after diagnosis were determined. IL-6 and MCP-1 values showed a significant increment at the end of induction. From the whole group 4 (10.0%), patients relapsed to the CNS at a median of 11.48months. A significantly higher value of TNF-α at third determination in these CNS-relapsed patients was documented, 7.48 vs. 2.86pg/mL in 36 children without relapse (p=0.024). TNF-α concentration increased at a median 5.48months before CNS relapse. By receiver-operating characteristic curve (ROC) analysis, the best cut-off point of TNF-α concentration that better predicted CNS relapse was ≥1.79pg/mL. In conclusion an increase in TNF-α concentration on CSF preceded CNS relapse in children with ALL. An increase in MCP-1 and IL-6 was not associated to CNS relapse and appears to result from an inflammatory response after IT injection of chemotherapy.

Comparison of aqueous concentrations of angiogenic and inflammatory cytokines based on optical coherence tomography patterns of diabetic macular edema

Purpose:

The purpose was to compare aqueous inflammatory and angiogenic cytokine levels in diabetic macular edema (DME).

Materials and Methods:

Aqueous samples were obtained from 50 eyes with DME and 12 normal eyes (control group). DME was classified according to the morphologic pattern based on optical coherence tomography: Diffuse retinal thickening (DRT; n = 19), cystoid macular edema (CME; n = 17), or serous retinal detachment (SRD; n = 14). Aqueous samples were collected just before intravitreal injection and at the beginning of cataract surgery in the control group. Interleukin (IL)-6, IL-8, interferon-induced protein (IP)-10, monocyte chemotactic protein (MCP)-1, platelet-derived growth factor (PDGF)-AA, and vascular endothelial growth factor (VEGF) levels were measured by multiplex bead assay.

Results:

The IL-6, IL-8, IP-10, and PDGF-AA levels differed significantly among the three groups of DME (P = 0.014, P = 0.038, P = 0.021, and P = 0.041, respectively). However, there were no differences between groups in aqueous concentration levels of MCP-1 and VEGF (P = 0.205 and P = 0.062, respectively). IL-6 (P = 0.026) and IL-8 (P = 0.023) correlated positively with central foveal thickness (CFT) in the CME group. None of the cytokine levels correlated significantly with CFT in any of the DRT and SRD groups.

Conclusions:

Aqueous concentrations of cytokines varied according to the morphologic pattern of DME, which might explain the variable response to treatments such as intravitreal bevacizumab or triamcinolone injection.

Inflammation and Notch signaling: a crosstalk with opposite effects on tumorigenesis

The Notch cascade is a fundamental and highly conserved pathway able to control cell-fate. The Notch pathway arises from the interaction of one of the Notch receptors (Notch1–4) with different types of ligands; in particular, the Notch pathway can be activated canonically (through the ligands Jagged1, Jagged2, DLL1, DLL3 or DLL4) or non-canonically (through various molecules shared by other pathways). In the context of tumor biology, the deregulation of Notch signaling is found to be crucial, but it is still not clear if the activation of this pathway exerts a tumor-promoting or a tumor suppressing function in different cancer settings. Untill now, it is well known that the inflammatory compartment is critically involved in tumor progression; however, inflammation, which occurs as a physiological response to damage, can also drive protective processes toward carcinogenesis. Therefore, the role of inflammation in cancer is still controversial and needs to be further clarified. Interestingly, recent literature reports that some of the signaling molecules modulated by the cells of the immune system also belong to or interact with the canonical and non-canonical Notch pathways, delineating a possible link between Notch activation and inflammatory environment. In this review we analyze the hypothesis that specific inflammatory conditions can control the activation of the Notch pathway in terms of biological effect, partially explaining the dichotomy of both phenomena. For this purpose, we detail the molecular links reported in the literature connecting inflammation and Notch signaling in different types of tumor, with a particular focus on colorectal carcinogenesis, which represents a perfect example of context-dependent interaction between malignant transformation and immune response.

SN38 increases IL-8 expression through the MAPK pathways in HCT8 cells

The overexpression of interleukin-8 (IL-8) is closely associated with poor tumor differentiation, metastasis and tumor progression. This study aimed to examine the effects and mechanisms of action of SN38 (a metabolite of the camptothecin derivative, CPT-11) on IL-8 expression in HCT8 cells, using ELISA, CCK-8 and western blot analysis. Among jatrorrhizine, evodiamine, 5-fluorouracil and SN38, SN38 was found to inhibit the proliferation of HCT8 cells in a dose-dependent manner, but to increase IL-8 secretion from HCT8 cells. Of the other agents, evodiamine was found to inhibit both IL-8 secretion and cell proliferation, and jatrorrhizine was found to increase IL-8 secretion without any obvious inhibitory effect on cell proliferation. Further experiments revealed that the increased activation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK)1/2 and c-Jun N-terminal kinase (JNK) by SN38 contributed to the decreased cell proliferation and to the overexpression of IL-8 induced by SN38. Our results suggested that the MAPK pathways are activated by SN38, resulting in the upregulation of IL-8 expression and in the inhibition of cell proliferation in an IL-8-independent manner. Thus, the potential benefit of the use of a combination of camptothecin-11 with other chemical drugs with inhibitory effects on IL-8 expression, should be paid more attention in treating colon cancer.

NF-κB-Mediated CCL20 Reigns Dominantly in CXCR2-Driven Ovarian Cancer Progression

Ovarian cancer is an inflammation-associated malignancy with a high mortality rate. CXCR2 expressing ovarian cancers are aggressive with poorer outcomes. We previously demonstrated that CXCR2-driven ovarian cancer progression potentiated NF-κB activation through EGFR-transactivated Akt. Here, we identified the chemokine signature involved in CXCR2-driven ovarian cancer progression using a mouse peritoneal xenograft model for ovarian cancer spreading with CXCR2-negative (SKA) and positive (SKCXCR2) cells generated previously from parental SKOV-3 cells. Compared to SKA bearing mice, SKCXCR2 bearing mice had the following characteristics: 1) shorter survival time, 2) greater tumor spreading in the peritoneal cavity and 3) higher tumor weight in the omentum and pelvic site. Particularly, SKCXCR2-derived tumor tissues induced higher activation of the NF-κB signaling pathway, while having no change in EGFR-activated signaling such as Raf, MEK, Akt, mTOR and Erk compared to SKA-derived tumors. Chemokine PCR array revealed that CCL20 mRNA levels were significantly increased in SKCXCR2-derived tumor tissues. The CCL20 promoter activity was regulated by NF-κB dependent pathways. Interestingly, all three κB-like sites in the CCL20 promoter were involved in regulating CCL20 and the proximal region between -92 and -83 was the most critical κB-like site. In addition, SKCXCR2-derived tumor tissues maintained high CCL20 mRNA expression and induced greater CCL24 and CXCR4 compared to SKCXCR2 cells, indicating the shift of chemokine network during the peritoneal spreading of tumor cells via interaction with other cell types in tumor microenvironment. Furthermore, we compared expression profiling array between human ovarian cancer cell lines and tumor tissues based on GEO datasets. The expression profiles in comparison with cell lines revealed that dominant chemokines expressed in ovarian tumor tissues are likely shifted from CXCL1-3 and 8 to CCL20. Taken together, the progression of ovarian cancer in the peritoneal cavity involves NF-κB-mediated CCL20 as a main chemokine network, which is potentiated by CXCR2 expression.

Extracellular matrix gene expression profiling using microfluidics for colorectal carcinoma stratification

In cancer, biomarkers have many potential applications including generation of a differential diagnosis, prediction of response to treatment, and monitoring disease progression. Many molecular biomarkers have been put forward for different diseases but most of them do not possess the required specificity and sensitivity. A biomarker with a high sensitivity has a low specificity and vice versa. The inaccuracy of the biomarkers currently in use has led to a compelling need to identify more accurate markers with diagnostic and prognostic significance. The aim of the present study was to use a novel, droplet-based, microfluidic platform to evaluate the prognostic value of a panel of thirty-four genes that regulate the composition of extracellular matrices in colorectal carcinoma. Our method is a novel approach as it uses using continuous-flowing Polymerase Chain Reaction for the sensitive detection and accurate quantitation of gene expression. We identified a panel of relevant extracellular matrix genes whose expression levels were measured by real-time quantitative polymerase chain reaction using Taqman^® reagents in twenty-four pairs of matched colorectal cancer tumour and associated normal tissue. Differential expression patterns occurred between the normal and malignant tissue and correlated with histopathological parameters and overall surgical staging. The findings demonstrate that a droplet-based microfluidic quantitative PCR system enables biomarker classification. It was further possible to sub-classify colorectal cancer based on extracellular matrix protein expressing groups which in turn correlated with prognosis.

Neutrophils assist the metastasis of circulating tumor cells in pancreatic ductal adenocarcinoma: A new hypothesis and a new predictor for distant metastasis

During our research on circulating tumor cells (CTCs) derived from tumor-adjacent vessels in pancreatic ductal adenocarcinoma (PDAC), we found that CTCs are sometimes surrounded by white blood cells (WBCs) in blood. We hypothesize that such interaction between WBCs and CTCs in blood is a mechanism by which WBCs assist in the metastasis of CTCs. We present our laboratory finding, with our evaluation of the association between the neutrophil-to-lymphocyte ratio (NLR, the most investigated clinical parameter of WBCs) and distant metastasis after curative surgery in PDAC. The laboratory finding was presented through immunofluorescence. In the clinical segment, we performed a retrospective study on PDAC patients with distant metastasis after curative surgery who were referred to Peking University Third Hospital between 2005 and 2014. The data on the possible clinical factors were collected by a retrospective review of the patients' records. Immunofluorescence results showed that CTCs are surrounded by WBCs in tumor-adjacent vessels of PDAC patients. In the clinical segment, 112 (70%) of a total of 160 PDAC patients were found to have developed distant metastases after surgery; among the 112 patients, only 89 had entire data and were enrolled for further analysis (84.3% patients had liver metastasis). No significant association was found between the NLR and overall survival (hazard ratio [HR] = 1.027, 95% confidence interval [CI] 0.723-1.459, P = 0.88); however, a significant relationship between the NLR and distant metastasis after curative surgery was found on the univariate (HR = 1.641, 95% CI 1.058-2.545, P = 0.027) and multivariate analyses (HR = 2.15, 95% CI 1.279-3.615, P = 0.004). Neutrophils might assist in distant metastasis through interaction with CTCs in blood. Moreover, NLR is an effective predictor for distant metastasis after curative surgery for PDAC.

Influence of mTOR-inhibitors and mycophenolic acid on human cholangiocellular carcinoma and cancer associated fibroblasts

Background

The incidence of Cholangiocellular Carcinoma (CCA) is increasing in the western world. The tumour has a high proportion of desmoplastic stroma and is correlated with a worse prognosis when cancer associated myofibroblasts (CAFs) are present. Recent studies showed promising results after liver transplantation (LTx) in non-resectable early stage CCA. Mycophenolic acid (MPA) and the mTor inhibitor Everolimus are used to prevent organ rejection but recently were shown to exhibit an antiproliferative effect on CCA-cells. Little is known about the influence of immunosuppressive drugs on tumour cell proliferation and migration after paracrine stimulation by CAFs. Moreover, it is still unknown, which signaling pathways are activated following these specific cell-cell interactions.

Methods

CCA cell lines HuCCT1 and TFK1 were utilized for the study. CAFs were derived from resected CCA cancer tissue. Cell viability was measured by the crystal violet assay and tumour cell invasion was quantified using a modified co-culture transmigration assay. Semiquantitative cytokine-expression was measured using a cytokine-array. Protein expression and phosphorylation of ERK, STAT3 and AKT was determined by Western-blot analysis.

Results

CCA cells treated with MPA exhibited a dose related decrease in cell viability in contrast to Cyclosporine A (CSA) treatment which had no effect on cell viability. Everolimus significantly inhibited proliferation at very low concentrations. The pro-invasive effect of CAFs in co-culture transmigration assay was significantly reduced by Everolimus at a concentration of 1nM (p = 0.047). In contrast, MPA and CSA showed no effect on tumour cell invasion. Treatment of CAFs with 1nM Everolimus showed a significant reduction in the expression of IL 8, IL 13, MCP1, MIF and Serpin E1. CCA-cells showed significant increases in phosphorylation of ERK, STAT3 and AKT under the influence of conditioned CAF-media. This effect was suppressed by Everolimus.

Conclusions

The secretion of proinflammatory cytokines by CAFs may lead to increased activation of JAK/STAT3-, ERK- and AKT-signaling and increased migration of CCA-cells. Everolimus abrogates this effect and inhibits proliferation of CCA-cells even at low concentrations.

LTx for non-resectable early stage CCA is currently performed in several clinical studies. Consistent with a role for common immunosuppressants in inhibiting tumour cell-proliferation and -invasion, our study indicates that a combination of standard therapies with Everolimus and MPA is a promising therapy option to treat CCA following LTx.

The Role of Chemokines in Promoting Colorectal Cancer Invasion/Metastasis

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Although most of the primary CRC can be removed by surgical resection, advanced tumors sometimes show recurrences in distant organs such as the liver, lung, lymph node, bone or peritoneum even after complete resection of the primary tumors. In these advanced and metastatic CRC, it is the tumor-stroma interaction in the tumor microenvironment that often promotes cancer invasion and/or metastasis through chemokine signaling. The tumor microenvironment contains numerous host cells that may suppress or promote cancer aggressiveness. Several types of host-derived myeloid cells reside in the tumor microenvironment, and the recruitment of them is under the control of chemokine signaling. In this review, we focus on the functions of chemokine signaling that may affect tumor immunity by recruiting several types of bone marrow-derived cells (BMDC) to the tumor microenvironment of CRC.

Tumor-associated fibroblasts promote the proliferation and decrease the doxorubicin sensitivity of liposarcoma cells

The reasons for the distinct chemoresistance of liposarcomas and their high risk of local recurrence still remain unclear. Depending on the histological subtype of liposarcoma, first-line therapy with the cytostatic agent, doxorubicin, only achieves response rates of approximately 36%. Approximatley 70% of all local recurrences develop in spite of complete surgical resection of the primary tumor with microscopically negative margins. In this study, we aimed to assess the influence of tumor-associated fibroblasts (TAFs) obtained from surgically removed liposarcomas on the well-established human liposarcoma SW872 cell line. Intratumoral TAFs were isolated from intermediate- and high-grade liposarcoma samples. The human liposarcoma cell line, SW872, was co-cultured with the corresponding TAFs or with dermal fibroblasts as a control. The proliferation (by BrdU assay), cell viability (by MTT assay) and sensitivity to doxorubicin (using the iCELLigence system) of the co-cultured SW872 cells were examined. The SW872 cells exhibited a significant increase in proliferation and viability when co-cultured with the TAFs. As detected by real-time cell analysis, the SW872 cells co-cultured with the TAFs exhibited a diminished response towards doxorubicin. Notably, co-culture with TAFs obtained from high-grade liposarcoma samples resulted in higher proliferation and increased chemoresistance than co-culture with TAFs obtained from intermediate-grade liposarcoma samples. The findings of the present study thus indicate that TAFs from liposarcomas enhance the proliferation and decrease the chemosensitivity of SW872 liposarcoma cells significantly compared with normal fibroblasts from the dermis. TAFs from more malignant liposarcomas promoted tumor cell proliferation and chemoresistance more strikingly than TAFs from less malignant liposarcomas. These data provide evidence for the influence of the tumor microenvironment on liposarcoma and support for further investigations in patients with different liposarcoma subentities, assessing the influence of TAFs on tumor progression.

Review: the Contribution of both Nature and Nurture to Carcinogenesis and Progression in Solid Tumours

Cancer is a leading cause of mortality worldwide. Cancer arises due to a series of somatic mutations that accumulate within the nucleus of a cell which enable the cell to proliferate in an unregulated manner. These mutations arise as a result of both endogenous and exogenous factors. Genes that are commonly mutated in cancer cells are involved in cell cycle regulation, growth and proliferation. It is known that both nature and nurture play important roles in cancer development through complex gene-environment interactions; however, the exact mechanism of these interactions in carcinogenesis is presently unclear. Key environmental factors that play a role in carcinogenesis include smoking, UV light and oncoviruses. Angiogenesis, inflammation and altered cell metabolism are important factors in carcinogenesis and are influenced by both genetic and environmental factors. Although the exact mechanism of nature-nurture interactions in solid tumour formation are not yet fully understood, it is evident that neither nature nor nurture can be considered in isolation. By understanding more about gene-environment interactions, it is possible that cancer mortality could be reduced.

Cellular and molecular effects of metronomic vinorelbine and 4-O-deacetylvinorelbine on human umbilical vein endothelial cells

Metronomic oral vinorelbine (VRL; Navelbine) was shown in clinical trials to yield sustainable antitumor activity possibly through antiangiogenic mechanisms. We investigated the effects of protracted low-dose VRL on human umbilical vein endothelial cells, compared with a conventional chemotherapy model. Human umbilical vein endothelial cell cultures were treated with different concentrations of VRL (0.001 nmol/l to 1 mmol/l) for 4, 24 and 96 h. The effects of different drug concentrations on cell growth, cell cycle, apoptosis and expression of the angiogenesis-modulating genes interleukin-8, cyclooxygenase-2, CD36 and peroxisome proliferator-activated receptor γ were assessed using the metronomic or conventional chemotherapy model. Apoptosis and cell-cycle effects were assessed by flow cytometry. Gene expression was measured at the transcript level by quantitative reverse transcriptase-PCR, protein expression by immunoblotting and levels of proteins secreted in the cell medium by enzyme-linked immunosorbent assay. Activation of the nuclear factor-κB pathway was investigated by immunoblot analysis of cytosolic and nuclear protein extracts. The half-maximal inhibitory concentrations (IC50) of VRL at 96 h were four orders lower compared with those after a 24-h exposure (1.23 nmol/l vs. 32 mmol/l for VRL). Drug concentrations at high nanomolar levels and above, which are relevant to conventional pulsatile dosing of VRL, induced a dose-dependent and nuclear factor-κB-related increase in proangiogenic interleukin-8 and cyclooxygenase-2 and a decrease in the thrombospondin-1 receptor CD36 and peroxisome proliferator-activated receptor γ at mRNA and protein levels. In contrast, the opposite was evident with protracted picomolar to low nanomolar concentrations (metronomic dosing). Our data provide experimental support for metronomic VRL by showing that a protracted low dose outperforms pulsed high-dose administration in inducing antiangiogenic effects in proliferating human endothelial cells.

The miR-27a-calreticulin axis affects drug-induced immunogenic cell death in human colorectal cancer cells

Immunogenic cell death (ICD) evoked by chemotherapeutic agents implies emission of selected damage-associated molecular patterns (DAMP) such as cell surface exposure of calreticulin, secretion of ATP and HMGB1. We sought to verify whether miR-27a is implicated in ICD, having demonstrated that it directly targets calreticulin. To this goal, we exposed colorectal cancer cell lines, genetically modified to express high or low miR-27a levels, to two bona fide ICD inducers (mitoxantrone and oxaliplatin). Low miR-27a-expressing cells displayed more ecto-calreticulin on the cell surface and increased ATP and HMGB1 secretion than high miR-27a-expressing ones in time-course experiments upon drug exposure. A calreticulin target protector counteracted the miR-27a effects while specific siRNAs mimicked them, confirming the results reported. In addition, miR-27a negatively influenced the PERK-mediated route and the late PI3K-dependent secretory step of the unfolded protein response to endoplasmic reticulum stress, suggesting that miR-27a modulates the entire ICD program. Interestingly, upon chemotherapeutic exposure, low miR-27a levels associated with an earlier and stronger induction of apoptosis and with morphological and molecular features of autophagy. Remarkably, in ex vivo setting, under the same chemotherapeutic induction, the conditioned media from high miR-27a-expressing cells impeded dendritic cell maturation while increased the secretion of specific cytokines (interleukin (IL)-4, IL-6, IL-8) and negatively influenced CD4⁺ T-cell interferon γ production and proliferation, all markers of a tumor immunoevasion strategy. In conclusion, we provide the first evidence that miR-27a impairs the cell response to drug-induced ICD through the regulatory axis with calreticulin.

Obesity and Obese-related Chronic Low-grade Inflammation in Promotion of Colorectal Cancer Development

Colorectal cancer (CRC) is a worldwide health problem, being the third most commonly detected cancer in males and the second in females. Rising CRC incidence trends are mainly regarded as a part of the rapid 'Westernization' of life-style and are associated with calorically excessive high-fat/low-fibre diet, consumption of refined products, lack of physical activity, and obesity. Most recent epidemiological and clinical investigations have consistently evidenced a significant relationship between obesity-driven inflammation in particular steps of colorectal cancer development, including initiation, promotion, progression, and metastasis. Inflammation in obesity occurs by several mechanisms. Roles of imbalanced metabolism (MetS), distinct immune cells, cytokines, and other immune mediators have been suggested in the inflammatory processes. Critical mechanisms are accounted to proinflammatory cytokines (e.g. IL-1, IL-6, IL-8) and tumor necrosis factor-α (TNF-α). These molecules are secreted by macrophages and are considered as major agents in the transition between acute and chronic inflammation and inflammation-related CRC. The second factor promoting the CRC development in obese individuals is altered adipokine concentrations (leptin and adiponectin). The role of leptin and adiponectin in cancer cell proliferation, invasion, and metastasis is attributable to the activation of several signal transduction pathways (JAK/STAT, mitogen-activated protein kinase (MAPK), phosphatidylinositol 3 kinase (PI3K), mTOR, and 5'AMPK signaling pathways) and multiple dysregulation (COX-2 downregulation, mRNA expression).

Inflammation increases NOTCH1 activity via MMP9 and is counteracted by Eicosapentaenoic Acid-free fatty acid in colon cancer cells

Aberrant NOTCH1 signalling is critically involved in multiple models of colorectal cancer (CRC) and a prominent role of NOTCH1 activity during inflammation has emerged. Epithelial to Mesenchymal Transition (EMT), a crucial event promoting malignant transformation, is regulated by inflammation and Metalloproteinase-9 (MMP9) plays an important role in this process. Eicosapentaenoic Acid (EPA), an omega-3 polyunsaturated fatty acid, was shown to prevent colonic tumors in different settings. We recently found that an extra-pure formulation of EPA as Free Fatty Acid (EPA-FFA) protects from colon cancer development in a mouse model of Colitis-Associated Cancer (CAC) through modulation of NOTCH1 signalling. In this study, we exposed colon cancer cells to an inflammatory stimulus represented by a cytokine-enriched Conditioned Medium (CM), obtained from THP1-differentiated macrophages. We found, for the first time, that CM strongly up-regulated NOTCH1 signalling and EMT markers, leading to increased invasiveness. Importantly, NOTCH1 signalling was dependent on MMP9 activity, upon CM exposure. We show that a non-cytotoxic pre-treatment with EPA-FFA antagonizes the effect of inflammation on NOTCH1 signalling, with reduction of MMP9 activity and invasiveness. In conclusion, our data suggest that, in CRC cells, inflammation induces NOTCH1 activity through MMP9 up-regulation and that this mechanism can be counteracted by EPA-FFA.

Interactions between colon cancer cells and tumor-infiltrated macrophages depending on cancer cell-derived colony stimulating factor 1

Tumor-infiltrated macrophages were potential targets of the immune therapy for patients with colon cancer. Colony stimulating factor 1 (CSF1) is a primary chemoattractant and functional regulator for macrophages, and therefore would be a feasible intervention for the macrophage-targeting therapeutics. However, the expression of CSF1 in colon cancer microenvironment and its roles in cancer development is largely unknown. In the present study, we found that CSF1 was over-expressed exclusively in colon cancer cells and was correlated with macrophages infiltration. The high CSF1 expression and macrophages infiltration were related to the tumor-node-metastasis (TNM) stage of colon cancer, and suggested to be positively associated with survival of colon cancer patients. In the in vitro studies based on an indirect Transwell system, we found that co-culture with macrophage promoted CSF1 production in colon cancer cells. Further investigation on regulatory mechanisms suggested that CSF1 production in colon cancer cells was dependent on PKC pathway, which was activated by IL-8, mainly produced by macrophages. Moreover, colon cancer cell-derived CSF1 drove the recruitment of macrophages and re-educated their secretion profile, including the augment of IL-8 production. The mice tumor xenografts study also found that over-expression of CSF1 in colon cancer cells promoted intratumoral infiltration of macrophages, and partially suppressed tumor growth. In all, our results demonstrated that CSF1 was an important factor in the colon cancer microenvironment, involving in the interactions between colon cancer cells and tumor-infiltrated macrophages.

Trefoil Factor-3 (TFF3) Stimulates De Novo Angiogenesis in Mammary Carcinoma both Directly and Indirectly via IL-8/CXCR2

Mammary carcinoma cells produce pro-angiogenic factors to stimulate angiogenesis and tumor growth. Trefoil factor-3 (TFF3) is an oncogene secreted from mammary carcinoma cells and associated with poor prognosis. Herein, we demonstrate that TFF3 produced in mammary carcinoma cells functions as a promoter of tumor angiogenesis. Forced expression of TFF3 in mammary carcinoma cells promoted proliferation, survival, invasion and in vitro tubule formation of human umbilical vein endothelial cells (HUVEC). MCF7-TFF3 cells with forced expression of TFF3 generated tumors with enhanced microvessel density as compared to tumors formed by vector control cells. Depletion of TFF3 in mammary carcinoma cells by siRNA concordantly decreased the angiogenic behavior of HUVEC. Forced expression of TFF3 in mammary carcinoma cells stimulated IL-8 transcription and subsequently enhanced IL-8 expression in both mammary carcinoma cells and HUVEC. Depletion of IL-8 in mammary carcinoma cells with forced expression of TFF3, or antibody inhibition of IL-8, partially abrogated mammary carcinoma cell TFF3-stimulated HUVEC angiogenic behavior in vitro, as did inhibition of the IL-8 receptor, CXCR2. Depletion of STAT3 by siRNA in MCF-7 cells with forced expression of TFF3 partially diminished the angiogenic capability of TFF3 on stimulation of cellular processes of HUVEC. Exogenous recombinant hTFF3 also directly promoted the angiogenic behavior of HUVEC. Hence, TFF3 is a potent angiogenic factor and functions as a promoter of de novo angiogenesis in mammary carcinoma, which may co-coordinate with the growth promoting and metastatic actions of TFF3 in mammary carcinoma to enhance tumor progression.

IL-8, a novel messenger to cross-link inflammation and tumor EMT via autocrine and paracrine pathways (Review)

The epithelial-mesenchymal transition (EMT) is a process through which epithelial cells trans-differentiate and acquire an aggressive mesenchymal phenotype. In tumor cells, EMT is a vital step of tumor progression and metastasis. Amid the increasing interest in tumor EMT, only a few studies focused on the soluble mediators secreted by tumor cells passing through this phenotypic switch. In this review, we focus on the essential role of interleukin-8 (IL-8) signaling for the acquisition and maintenance of tumor EMT via direct and indirect mechanisms. Besides the autocrine loop between IL-8 and tumor cells that have gone through EMT, IL-8 could potentiate adjacent epithelial tumor cells into a mesenchymal phenotype via a paracrine mode. Moreover, understanding the role of IL-8 in EMT will provide insight into the pathogenesis of tumor progression and may facilitate the development of an effective strategy for the prevention and treatment of metastatic cancer.

CXCR2-CXCL1 axis is correlated with neutrophil infiltration and predicts a poor prognosis in hepatocellular carcinoma

Background & aims

Inflammation is a hallmark of cancer, yet the mechanisms that regulate immune cell infiltration into tumors remain poorly characterized. This study attempted to characterize the composition, distribution, and prognostic value of CXCR2⁺ cells in hepatocellular carcinoma (HCC) and to examine the CXCR2 ligands that are responsible for local immune infiltration in different areas of HCC tumors.

Methods

Immunohistochemistry and immunofluorescene were used to identify CXCR2⁺ cells in HCC tissues. Kaplan–Meier analysis and Cox regression models were applied to estimate recurrence-free survival (RFS) and overall survival (OS) for 259 HCC patients. The expression levels of CXCR2 ligands (CXCL-1, −2, −5, and −8) were measured by real-time PCR and compared with local immune cell density. The combined prognostic value of the CXCR2–CXCL1 axis was further evaluated.

Results

In HCC tissues, CXCR2⁺ cells were mainly neutrophils that were enriched in the peri-tumoral stroma (PS) region. Kaplan–Meier survival analysis showed that increased CXCR2⁺_PS cells were associated with reduced RFS and OS (P = 0.015 for RFS; P = 0.002 for OS). Multivariate Cox proportional hazards analysis identified CXCR2⁺_PS cell density as an independent prognostic factor for OS (hazard ratio [HR] = 1.737, 95 % confidence interval [CI] = 1.167–2.585, P = 0.006). Furthermore, we detected a positive correlation between the density of CD15⁺ neutrophils and CXCL1 levels in both the peri-tumoral stroma and intra-tumoral regions. The combination of CXCR2 and CXCL1 expression levels represented a powerful predictor of a poor prognosis for patients with HCC.

Conclusions

Our data showed that the CXCR2⁺ cell density was an independent prognostic factor for predicting OS for HCC patients. The CXCR2–CXCL1 axis can regulate neutrophil infiltration into HCC tumor tissues and might represent a useful target for anti-HCC therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0247-1) contains supplementary material, which is available to authorized users.

Development of individualized anti-metastasis strategies by engineering nanomedicines

Metastasis is deadly and also tough to treat as it is much more complicated than the primary tumour. Anti-metastasis approaches available so far are far from being optimal. A variety of nanomedicine formulae provide a plethora of opportunities for developing new strategies and means for tackling metastasis. It should be noted that individualized anti-metastatic nanomedicines are different from common anti-cancer nanomedicines as they specifically target different populations of malignant cells. This review briefly introduces the features of the metastatic cascade, and proposes a series of nanomedicine-based anti-metastasis strategies aiming to block each metastatic step. Moreover, we also concisely introduce the advantages of several promising nanoparticle platforms and their potential for constructing state-of-the-art individualized anti-metastatic nanomedicines.

Primary tumor- and metastasis-derived colon cancer cells differently modulate connexin expression and function in human capillary endothelial cells

A gradual loss of functional gap junction between tumor cells has been reported with colorectal cancer (CRC) progression. Here, we explored if colon cancer cells could also affect gap junctions in blood capillary cells. Human microvascular endothelial cells (HMEC) were cultured with two CRC cell lines established from a unique patient. SW480 cells, derived from the primary tumor, migrate much faster across HMEC monolayer than SW620 cells derived from a metastatic site. The motile SW480 cells highly express and release HSP27 that increases gap junction formation with HMEC. Soluble HSP27 phosphorylates the connexin Cx43 on serine residues and induces its interaction with the oncoprotein 14-3-3, which promotes Cx43 delivery at the plasma membrane. The factors secreted by less motile SW620 cells do not affect Cx43 expression but up-regulate the expression of the connexin Cx32 through an activation of the chemokine receptor CXCR2. In turn, SW620 secreted factors induce tubulogenesis and ATP release. Altogether, cell lines derived from CRC primary tumor and metastasis differentially adapt endothelial cell functions by modulating connexin expression through released mediators.

Interleukin-8 Induces Expression of FOXC1 to Promote Transactivation of CXCR1 and CCL2 in Hepatocellular Carcinoma Cell Lines and Formation of Metastases in Mice

BACKGROUND & AIMS

Inflammation regulated by interleukin (IL) 8 promotes metastasis of hepatocellular carcinoma (HCC). The transcription factor forkhead box C1 (FOXC1) promotes metastasis by activating the epithelial to mesenchymal transition; its levels in liver tumors have been associated with shorter survival times of patients. We investigated whether FOXC1 activates inflammation signaling pathways in HCC cell lines.

METHODS

We performed studies in the human HCC cell lines Huh-7 and SMMC7721, as well as the metastatic cell lines MHCC97H and HCCLM3. Cell lines were incubated with IL8 and transcription of reporter genes was measured; cells were also incubated with kinase inhibitors. Levels of FOXC1 or IL8 were knocked down with small interfering messenger RNAs in Huh7 cells; cells were analyzed in vitro in migration and invasion assays. To study metastasis, HCC cells were injected into flanks of BALB/C nude mice; 4 weeks later, the subcutaneous tumor fragments were collected and implanted into livers of the nude mice, and number and size tumors formed were measured. Chromatin immunoprecipitation assays were used to measure binding of transcription factors promoter regions of genes. We measured levels of FOXC1, IL8, CXCR1, and CCL2 in 2 groups of human HCC tissues collected from the Xijing or Tongji Hospitals in China (n = 690 and n = 312 samples, respectively) using immunohistochemistry.

RESULTS

Incubation of HCC cells with IL8 led to increased expression of FOXC1, via activation of phosphoinositide 3-kinase signaling to AKT and hypoxia-inducible factor 1α. Knockdown of FOXC1 in HCC cells that overexpressed IL8 reduced the numbers of metastases formed in mice, compared with cells without FOXC1 knockdown. Transgenic overexpression of FOXC1 in HCC cells with IL8 knockdown increased the numbers of metastases formed in mice compared with cells without FOXC1 overexpression. CXCR1 and CCL2 were direct transcriptional targets of FOXC1. Knockdown of the combination of CXCR1 and CCL2 reduced the invasive activities of HCC cells that overexpress FOXC1 and formation of lung metastases in mice, and transgenic overexpression of CXCR1 increased cell's invasive and metastatic abilities after knockdown of FOXC1. Liver metastases grown from cells that overexpressed FOXC1 were infiltrated by tumor-associated macrophages, and CCL2 knockdown decreased tumor-associated macrophage infiltration; depletion of macrophages from mice significantly reduced growth of metastases by cells that overexpressed FOXC1. In human HCC tissues, level of FOXC1 correlated with levels of IL8 and CXCR1 and CCL2 and infiltration of tumors by macrophage. In multivariate analysis, detection of FOXC1 and CCL2 were independent predictors for postoperative recurrence of HCC and overall survival.

CONCLUSIONS

In HCC cell lines, IL8 activates expression of FOXC1 via the phosphoinositide 3-kinase signaling to AKT and hypoxia-inducible factor 1α. FOXC1 expression leads to transactivation of CXCR1 and CCL2, promoting inflammation and the invasive and metastatic abilities of HCC cells.

Cycling hypoxia induces a specific amplified inflammatory phenotype in endothelial cells and enhances tumor-promoting inflammation in vivo

Abnormal architecture of the tumor blood network, as well as heterogeneous erythrocyte flow, leads to temporal fluctuations in tissue oxygen tension exposing tumor and stromal cells to cycling hypoxia. Inflammation is another feature of tumor microenvironment and is considered as a new enabling characteristic of tumor progression. As cycling hypoxia is known to participate in tumor aggressiveness, the purpose of this study was to evaluate its role in tumor-promoting inflammation. Firstly, we assessed the impact of cycling hypoxia in vitro on endothelial inflammatory response induced by tumor necrosis factor α. Results showed that endothelial cells exposed to cycling hypoxia displayed an amplified proinflammatory phenotype, characterized by an increased expression of inflammatory cytokines, namely, interleukin (IL)-6 and IL-8; by an increased expression of adhesion molecules, in particular intercellular adhesion molecule-1 (ICAM-1); and consequently by an increase in THP-1 monocyte adhesion. This exacerbation of endothelial inflammatory phenotype occurs through nuclear factor-κB overactivation. Secondly, the role of cycling hypoxia was studied on overall tumor inflammation in vivo in tumor-bearing mice. Results showed that cycling hypoxia led to an enhanced inflammation in tumors as prostaglandin-endoperoxide synthase 2 (PTGS2), IL-6, CXCL1 (C-X-C motif ligand 1), and macrophage inflammatory protein 2 (murine IL-8 functional homologs) mRNA expression was increased and as a higher leukocyte infiltration was evidenced. Furthermore, cycling hypoxia-specific inflammatory phenotype, characterized by a simultaneous (baculoviral inhibitor of apoptosis repeat-containing 5)(low)/PTGS2(high)/ICAM-1(high)/IL-6(high)/IL-8(high) expression, is associated with a poor prognosis in human colon cancer. This new phenotype could thus be used in clinic to more precisely define prognosis for colon cancer patients. In conclusion, our findings evidenced for the first time the involvement of cycling hypoxia in tumor-promoting inflammation amplification.

Vitamin D, Inflammation, and Colorectal Cancer Progression: A Review of Mechanistic Studies and Future Directions for Epidemiological Studies

Survival from colorectal cancer is positively associated with vitamin D status. However, whether this association is causal remains unclear. Inflammatory processes may link vitamin D to colorectal cancer survival, and therefore investigating inflammatory markers as potential mediators may be a valuable next step. This review starts with an overview of inflammatory processes suggested to be involved in colorectal cancer progression and regulated by vitamin D. Next, we provide recommendations on how to study inflammatory markers in future epidemiologic studies on vitamin D and colorectal cancer survival. Mechanistic studies have shown that calcitriol-active form of vitamin D-influences inflammatory processes involved in cancer progression, including the enzyme cyclooxygenase 2, the NF-κB pathway, and the expression of the cytokines TNFα, IL1β, IL6, IL8, IL17, and TGFβ1. Based on this and taking into account methodologic issues, we recommend to include analysis of specific soluble peptides and proteins, such as cytokines, in future epidemiologic studies on this issue. Vitamin D and the markers should preferably be measured at multiple time points during disease progression or recovery and analyzed using mediation analysis. Including these markers in epidemiologic studies may help answer whether inflammation mediates a causal relationship between vitamin D and colorectal cancer survival.

Emerging cytokine networks in colorectal cancer

Cytokine networks are crucial aspects of tumour immunology, particularly for colorectal cancer (CRC), in which inflammation and antitumour immunity are key determinants of disease progression. In this Review, we highlight new insights into the functions of well-known cytokines in CRC, describe recently discovered roles for a growing number of novel players, and emphasize the complexity and therapeutic implications of the cytokine milieu. We also discuss how cancer mutations and epigenetic adaptations influence the oncogenic potential of cytokines, a relatively unexplored area that could yield crucial insights into tumour immunology and facilitate the effective application of cytokine-modulatory therapies for CRC.

Macrophage migration inhibitory factor: a key cytokine and therapeutic target in colon cancer

Macrophage migration inhibitory factor (MIF) was one of the first cytokines to be discovered, over 40 years ago. Since that time a burgeoning interest has developed in the role that MIF plays in both the regulation of normal physiology and the response to pathology. MIF is a pleotropic cytokine that functions to promote inflammation, drive cellular proliferation, inhibit apoptosis and regulate the migration and activation state of immune cells. These functions are particularly relevant for the development of cancer and it is notable that various solid tumours over express MIF. This includes tumours of the gastrointestinal tract and MIF appears to play a particularly prominent role in the development and progression of colonic adenocarcinoma. Here we review the role that MIF plays in colonic carcinogenesis through the promotion of colonic inflammation, as well as the progression of primary and metastatic colon cancer. The recent development of various antagonists and antibodies that inhibit MIF activity indicates that we may soon be able to classify MIF as a therapeutic target in colon cancer patients.

Changes of immunocytic phenotypes and functions from human colorectal adenomatous stage to cancerous stage: Update

It is believed that chronic inflammation as seen in patients with ulcerative colitis significantly increases the colorectal cancer (CRC) risk and functions as the main driving force for the development of colitis associated CRC. Recently, increasing evidences suggest that inflammation is also involved in the processing of sporadic CRCs that mostly develop from the preformed adenomas through a long-term progression. Within the adenoma/CRC tumor microenvironment, high dense immunocytes with significant phenotypic and functional changes have been observed. These cells might produce high level of inflammatory mediators and then affect the adenoma-cancer transition. In this review, we summarize the update on altered phenotypes and inflammatory mediators within the tumor microenvironment from the adenomatous stage to the cancerous stage, and discuss the significance of inflammatory mediators as biomarkers in predicating the progression from the premalignant adenoma lesion to the sporadic CRC lesion and the potential as therapeutic targets.

ATM regulation of IL-8 links oxidative stress to cancer cell migration and invasion

Ataxia-telangiectasia mutated (ATM) protein kinase regulates the DNA damage response (DDR) and is associated with cancer suppression. Here we report a cancer-promoting role for ATM. ATM depletion in metastatic cancer cells reduced cell migration and invasion. Transcription analyses identified a gene network, including the chemokine IL-8, regulated by ATM. IL-8 expression required ATM and was regulated by oxidative stress. IL-8 was validated as an ATM target by its ability to rescue cell migration and invasion defects in ATM-depleted cells. Finally, ATM-depletion in human breast cancer cells reduced lung tumors in a mouse xenograft model and clinical data validated IL-8 in lung metastasis. These findings provide insights into how ATM activation by oxidative stress regulates IL-8 to sustain cell migration and invasion in cancer cells to promote metastatic potential. Thus, in addition to well-established roles in tumor suppression, these findings identify a role for ATM in tumor progression.

miR-19-Mediated Inhibition of Transglutaminase-2 Leads to Enhanced Invasion and Metastasis in Colorectal Cancer

Transglutaminase-2 (TG2) is a critical cross-linking enzyme in the extracellular matrix (ECM) and tumor microenvironment (TME). Although its expression has been linked to colorectal cancer, its functional role in the processes that drive disease appears to be context dependent. There is now considerable evidence of a role for microRNAs (miRNA) in the development and progression of cancer, including metastasis. A cell model of metastatic colon adenocarcinoma was used to investigate the contribution of miRNAs to the differential expression of TG2, and functional effects on inflammatory and invasive behavior. The impact of TG2 in colorectal cancer was analyzed in human colorectal tumor specimens and by manipulations in SW480 and SW620 cells. Effects on invasive behavior were measured using Transwell invasion assays, and cytokine production was assessed by ELISA. TG2 was identified as a target for miR-19 by in silico analysis, which was confirmed experimentally. Functional effects were evaluated by overexpression of pre-miR-19a in SW480 cells. Expression of TG2 correlated inversely with invasive behavior, with knockdown in SW480 cells leading to enhanced invasion, and overexpression in SW620 cells the opposite. TG2 expression was observed in colorectal cancer primary tumors but lost in liver metastases. Finally, miR-19 overexpression and subsequent decreased TG2 expression was linked to chromosome-13 amplification events, leading to altered invasive behavior in colorectal cancer cells.

IMPLICATIONS

Chromosome-13 amplification in advanced colorectal cancer contributes to invasion and metastasis by upregulating miR-19, which targets TG2.

Malignancy of bladder cancer cells is enhanced by tumor-associated fibroblasts through a multifaceted cytokine-chemokine loop

The microenvironment of tumor cells is critically involved in tumor development and progression. Tumor-associated fibroblasts (TAFs) represent a major constituent of the tumor stroma. Tumor cells are operative in the activation of TAFs, whereas TAFs in turn contribute to tumor cell malignancy. This report describes mechanisms of communication between fibroblasts and urinary bladder cancer (UBC) cells. Migration of bladder cancer cell lines RT112 and Cal-29, representing two different grades of dedifferentiation, was enhanced by cocultivation with TAFs. Conditioned medium from tumor cells induced the release of interleukin (IL)-8, hepatocyte growth factor (HGF), matrix metalloproteinase-2, granulocyte macrophage colony-stimulating factor, and monocyte chemotactic protein (MCP)-1 by TAFs. Tumor cell-derived IL-1α was identified as a major mediator of these stimulatory effects. Fibroblasts, on the other hand, exerted a migration and invasion stimulating influence on UBC cells. MCP-1 and HGF were shown to promote cell migration of both bladder cancer cell lines.

Association of high expression of Groβ with clinical and pathological characteristics of unfavorable prognosis in gastrointestinal stromal tumors

GROβ (CXCL2) is a chemokine produced by endotoxin-treated macrophages that mediates inflammation and tumor development. However, little is known about GROβ expression in gastrointestinal stromal tumors (GIST) or the relationship between GROβ expression and clinical attributes of GIST. GROβ expression was examined via immunohistochemical staining of 173 GIST samples using tissue microarray. The relationship between GROβ expression and relevant patient and tumor characteristics was assessed, using chi-square tests. Univariate and multivariate analysis was carried out using the Cox regression method. High GROβ cytoplasm staining was detected in 56 (32.4%) specimens; high GROβ nuclear staining was detected in 64 (37.0%) specimens. High GROβ cytoplasm staining was significantly associated with patients' age (P = 0.043) and tumor location (P = 0.014), while high GROβ nucleus staining was significantly associated with mitotic index (P = 0.034), tumor location (P = 0.049), and AFIP-Miettinen risk classification (P = 0.048). Kaplan-Meier survival curves showed GIST patients with low GROβ cytoplasm expression (P = 0.023) and mitotic index < 6 per 50 HPFs (P = 0.026) to have a more favorable prognosis. These findings indicate that GROβ expression correlates with malignant GIST phenotypes and could be an unfavorable prognostic marker in patients with GIST.

IL8-CXCR2 pathway inhibition as a therapeutic strategy against MDS and AML stem cells

Acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are associated with disease-initiating stem cells that are not eliminated by conventional therapies. Novel therapeutic targets against preleukemic stem cells need to be identified for potentially curative strategies. We conducted parallel transcriptional analysis of highly fractionated stem and progenitor populations in MDS, AML, and control samples and found interleukin 8 (IL8) to be consistently overexpressed in patient samples. The receptor for IL8, CXCR2, was also significantly increased in MDS CD34(+) cells from a large clinical cohort and was predictive of increased transfusion dependence. High CXCR2 expression was also an adverse prognostic factor in The Cancer Genome Atlas AML cohort, further pointing to the critical role of the IL8-CXCR2 axis in AML/MDS. Functionally, CXCR2 inhibition by knockdown and pharmacologic approaches led to a significant reduction in proliferation in several leukemic cell lines and primary MDS/AML samples via induction of G0/G1 cell cycle arrest. Importantly, inhibition of CXCR2 selectively inhibited immature hematopoietic stem cells from MDS/AML samples without an effect on healthy controls. CXCR2 knockdown also impaired leukemic growth in vivo. Together, these studies demonstrate that the IL8 receptor CXCR2 is an adverse prognostic factor in MDS/AML and is a potential therapeutic target against immature leukemic stem cell-enriched cell fractions in MDS and AML.

Overexpression of chemokine receptor CXCR2 and ligand CXCL7 in liver metastases from colon cancer is correlated to shorter disease-free and overall survival

Our aim was to analyze the potential role of chemokine receptors CXCR2 and CXCR4 signalling pathways in liver metastatic colorectal cancer (CRC) relapse. CXCR2, CXCR4, and their chemokine ligands were evaluated in liver metastases of colorectal cancer in order to study their correlation with overall and disease-free survival of patients having received, or not received, a neoadjuvant chemotherapy regimen. Quantitative RT-PCR and CXCR2 immunohistochemical staining were carried out using CRC liver metastasis samples. Expression levels of CXCR2, CXCR4, and their ligands were statistically analyzed according to treatment with neoadjuvant chemotherapy and patients’ outcome. CXCR2 and CXCL7 overexpression are correlated to shorter overall and disease-free survival. By multivariate analysis, CXCR2 and CXCL7 expressions are independent factors of overall and disease-free survival. Neoadjuvant chemotherapy increases significantly the expression of CXCR2: treated group 1.89 (0.02–50.92) vs 0.55 (0.07–3.22), P = 0.016. CXCL7 was overexpressed close to significance, 0.40 (0.00–7.85) vs 0.15 (0.01–7.88), P = 0.12. We show the involvement of CXCL7/CXCR2 signalling pathways as a predictive factor of poor outcome in metastatic CRC. 5-Fluorouracil-based chemotherapy regimens increase the expression of these genes in liver metastasis, providing one explanation for aggressiveness of relapsed drug-resistant tumors. Selective blockage of CXCR2/CXCL7 signalling pathways could provide new potential therapeutic opportunities.

Pb²⁺ induced IL-8 gene expression by extracellular signal-regulated kinases and the transcription factor, activator protein 1, in human gastric carcinoma cells

Divalent lead (Pb(2+) ) is a common industrial pollutant epidemiologically associated with gastric cancers. Pb(2+) was found to promote tumorigenesis, which may include interleukin (IL)-8, a pro-inflammatory chemokine that promotes angiogenesis and tumor metastasis. Given that the gastrointestinal tract is a major route of Pb(2+) exposure, we investigated the ability of Pb(2+) to induce IL-8 expression in gastric carcinoma cells and its underlying mechanism. At a concentration of 0.1 μM, Pb(2+) induced IL-8 gene activation in gastric carcinoma AGS cells. Using a IL-8 promoter-deletion analysis, transcription factor activator protein 1 (AP-1) was identified as a necessary component of Pb(2+) -induced IL-8 gene activation. Upregulation of the IL-8 gene was abrogated by the MEK inhibitor, PD98059, and partially suppressed by the epidermal growth factor receptor inhibitors, AG1478 and PD153035. Furthermore, c-Jun protein expression was induced in cells treated with Pb(2+) , and overexpression of c-Jun enhanced Pb(2+) -induced IL-8 activation. Collectively, our findings highlight the pivotal roles of AP-1 and extracellular signal-regulated kinase in signal transduction of Pb(2+) -induced IL-8 gene activation. These molecules may be potential therapeutic targets for Pb(2+) -related inflammation leading to stomach carcinogenesis. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 315-322, 2015.

Inflammatory and redox reactions in colorectal carcinogenesis

It has been established that there is a relationship between chronic inflammation and cancer development. The constant colonic inflammation typical of inflammatory bowel diseases is now considered a risk factor for colorectal carcinoma (CRC) development. The inflammatory network of signaling molecules is also required during the late phases of carcinogenesis, to enable cancer cells to survive and to metastasize. Oxidative reactions are an integral part of the inflammatory response, and are generally associated with CRC development. However, when the malignant phenotype is acquired, increased oxidative status induces antioxidant defenses in cancer cells, favoring their aggressiveness. This contradictory behavior of cancer cells toward redox status is of great significance for potential anticancer therapies. This paper summarizes the essential background information relating to the molecules involved in regulating oxidative stress and inflammation during carcinogenesis. Understanding more of their function in CRC stages might provide the foundation for future developments in CRC treatment.

Fas and TRAIL 'death receptors' as initiators of inflammation: Implications for cancer

Fas (CD95/APO-1) and TRAIL (CD253, TNFSF10, APO2) are members of a subset of the TNF receptor superfamily known as 'death receptors'. To date, the overwhelming majority of studies on Fas and TRAIL (TNF-related apoptosis-inducing ligand) have explored the role of these receptors as initiators of apoptosis. However, sporadic reports also suggest that engagement of the Fas and TRAIL receptors can lead to other outcomes such as cytokine and chemokine production, cell proliferation, cell migration and differentiation. Indeed, although transformed cells frequently express Fas and TRAIL, most do not undergo apoptosis upon engagement of these receptors and significant effort has been devoted toward exploring how to sensitize such cells to the pro-apoptotic effects of 'death receptor' stimulation. Moreover, the expression of Fas and TRAIL receptors is greatly elevated in many cancer types such as hepatocellular carcinoma, renal carcinoma and ovarian cancer, suggesting that such tumors benefit from the expression of these receptors. Furthermore, several studies have shown that tumor proliferation, progression and invasion can be impaired through blocking or downregulation of Fas expression, but the mechanistic basis for these effects is largely unknown. Thus, the characterization of Fas and TRAIL as 'death receptors' is a gross oversimplification, especially in the context of cancer. It is becoming increasingly clear that 'death receptor' engagement can lead to outcomes, other than apoptosis, that become subverted by certain tumors to their benefit. Here we will discuss death-independent outcomes of Fas and TRAIL signaling and their implications for cancer.

Regulatory MiR-148a-ACVR1/BMP circuit defines a cancer stem cell-like aggressive subtype of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third most common cancer in Asia. HCC has heterogeneous etiologic and molecular profiles and a varied response to therapeutics. The high recurrence rate and curtailed survival in this cancer are attributed to its resistance to therapy. The ultimate goal is to develop a more effective personalized therapeutic strategy for HCC, but the first step is to develop a system for classifying the disease on the basis of molecular biomarkers. To that end, we performed mRNA and microRNA (miRNA) expression profiling in 100 HCC tissues. Clustering analysis of informative genes identified two robust subtypes, which were validated by an independent dataset. The subtype characterized by a cancer stem cell-like signature was clinically aggressive and associated with poor survival. Integrated analysis of miRNA and mRNA expression in this subtype showed that miR-148a was expressed at a significantly lower level in these tumors than in the other subtype. MiR-148a has been shown to directly suppress the expression of activin A receptor type 1 (ACVR1), a key receptor in the signaling pathway of the bone morphogenetic proteins (BMPs), which regulate many stem cell markers as well as the clinically important cytokine interleukin-8 (IL-8). Increased expression of ACVR1 and its downstream genes EPCAM, CD24, CD90, and IL-8 was associated with shorter survival in a larger cohort of 227 HCC cases. Introduction of miR-148a resulted in suppressed tumor phenotypes both in vitro and in vivo.

CONCLUSION

We identified a clinically aggressive stem cell-like subtype of HCC that is characterized by an miR-148a-ACVR1-BMP-Wnt circuit. We propose that miR-148a may serve as a prognostic biomarker and therapeutic target for this subtype of HCC.

Cytokines, IBD, and colitis-associated cancer

Inflammatory bowel diseases (IBDs) are debilitating conditions that result in intestinal damage due to chronic inflammation. In addition, the perpetual state of inflammation predisposes individuals to the development of colitis-associated cancer. Because of the immense immune cell infiltration into colon, cytokines produced by immune cells are major players in the initiation and progression of IBD and colitis-associated cancer. In this review, we will explore the functions of many key cytokines and their roles in IBD and colitis-associated cancer, as well as their influences on the immune system and stromal cells. Finally, we will briefly discuss current therapies and current clinical trials targeting cytokines in IBD.

Minireview: Tipping the balance: ligand-independent activation of steroid receptors

Steroid receptors are prototypical ligand-dependent transcription factors and a textbook example for allosteric regulation. According to this canonical model, binding of cognate steroid is an absolute requirement for transcriptional activation. Remarkably, the simple one ligand-one receptor model could not be farther from the truth. Steroid receptors, notably the sex steroid receptors, can receive multiple inputs. Activation of steroid receptors by other signals, working through their own signaling pathways, in the absence of the cognate steroids, represents the most extreme form of signaling cross talk. Compared with cognate steroids, ligand-independent activation pathways produce similar but not identical outputs. Here we review the phenomena and discuss what is known about the underlying molecular mechanisms and the biological significance. We hypothesize that steroid receptors may have evolved to be trigger happy. In addition to their cognate steroids, many posttranslational modifications and interactors, modulated by other signals, may be able to tip the balance.

In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis

BACKGROUND AND OBJECTIVE

Development of miniaturized imaging systems with molecular probes enables examination of molecular changes leading to initiation and progression of colorectal cancer in an azoxymethane (AOM)-induced mouse model of the disease. Through improved and novel studies of animal disease models, more effective diagnostic and treatment strategies may be developed for clinical translation. We introduce use of a miniaturized multimodal endoscope with lavage-delivered fluorescent probes to examine dynamic microenvironment changes in an AOM-treated mouse model.

STUDY DESIGN/MATERIALS AND METHODS

The endoscope is equipped with optical coherence tomography (OCT) and laser induced fluorescence (LIF) imaging modalities. It is used with Cy5.5-conjugated antibodies to create time-resolved molecular maps of colon carcinogenesis. We monitored in vivo changes in molecular expression over a five month period for four biomarkers: epithelial growth factor receptor (EGFR), transferrin receptor (TfR), transforming growth factor beta 1 (TGFβ1), and chemokine (C-X-C motif) receptor 2 (CXCR2). In vivo OCT and LIF images were compared over multiple time points to correlate increases in biomarker expression with adenoma development.

RESULTS

This system is uniquely capable of tracking in vivo changes in molecular expression over time. Increased expression of the biomarker panel corresponded to sites of disease and offered predictive utility in highlighting sites of disease prior to detectable structural changes. Biomarker expression also tended to increase with higher tumor burden and growth rate in the colon.

CONCLUSION

We can use miniaturized dual modality endoscopes with fluorescent probes to study the tumor microenvironment in developmental animal models of cancer and supplement findings from biopsy and tissue harvesting.

Chemokine receptor 7 promotes tumor migration and invasiveness via the RhoA/ROCK pathway in metastatic squamous cell carcinoma of the head and neck

Metastatic squamous cell carcinoma of the head and neck (SCCHN) has been shown to express chemokine receptor 7 (CCR7), which can activate signaling pathways to promote invasion and survival of SCCHN cells. We hypothesized that the RhoA/Rho-associated kinase (ROCK) pathway is involved in the CCR7-induced invasion and migration of metastatic SCCHN cells. Thus, using migration, matrigel invasion and scrape wound-healing assays, we elucidated the role of RhoA in mediating CCR7-associated cellular mobility. Pull-down assays and western blotting were used to measure RhoA and its downstream expression. Immunohistochemical staining and analysis were useful in identifying the correlation between CCR7 and RhoA expression and clinicopathological factors. The results showed that inhibition of RhoA/ROCK reduced the tumor cell migration and invasiveness induced by CCL19. Activated RhoA, proline-rich tyrosine kinase-2 (Pyk2) and cofilin induced by CCL19 were elevated, and increased RhoA, Pyk2 and cofilin activity was eliminated by CCR7mAb, RhoA/ROCK and Pyk2 inhibitors, indicating involvement of the RhoA/ROCK-Pyk2-cofilin cascade. In summary, CCR7 via RhoA/ROCK-Pyk2 cofilin pathway promotes invasion and migration of metastatic SCCHN cells.

Isolation and Characterization of Cancer Stem Cells in Renal Cell Carcinoma

Recently, several studies have investigated the presence of cancer stem cells in kidney cancer, performed characterization, and compared their profile with the normal stem cell counterparts. CD133, alone or in combination with other molecular markers, has been used to isolate normal and cancer stem cells from different sources, including renal carcinoma; however, it is still a matter of debate whether CD133+cells really represent the main tumorigenic population within the heterogeneous pool of cancer cells that characterize this tumor. In this review, we summarize and discuss the current findings related to cancer stem cells isolation in renal cell carcinoma, focusing on controversies about their origin and the identification of a specific marker.

Diagnostic value of interleukin-8 in colorectal cancer: a case-control study and meta-analysis

AIM

To assess the diagnostic value of serum interleukin-8 (IL-8) in the detection of colorectal cancer (CRC).

METHODS

An original study was conducted to explore the potential value of IL-8 in CRC diagnosis. Receiver operating characteristic (ROC) analysis was performed and the area under the curve (AUC) value was calculated. PUBMED and EMBASE were searched (to October, 2013), supplemented with manual screening for relevant publications. Meta-analysis methods were applied to pool sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratios and to construct a summary receiver-operating characteristic (sROC) curve. Heterogeneity across studies was checked by the I(2) test and Deek's funnel plot method was applied to test publication bias.

RESULTS

In our original study, serum IL-8 yielded an AUC of 0.742 [95%CI: 0.635-0.849]. The sensitivity and specificity were 85.42% and 54.05%, respectively, at a cut-off value of 5.39. In this meta-analysis, we included five studies with 668 CRC patients and 374 controls and one study in our own center with 48 CRC patients and 37 controls. The pooled sensitivity and specificity of IL-8 were 0.69 (95%CI: 0.42-0.87) and 0.85 (95%CI: 0.68-0.94) for CRC detection. Besides, the area under the sROC curve was 0.86 (95%CI: 0.82-0.88). Subgroup analysis suggested that there was no heterogeneity in the Asian subgroup but some in the European subgroup. In addition, no publication bias was found according to the Deek's funnel plot asymmetry test.

CONCLUSION

Serum IL-8 is a promising biomarker for CRC detection and may become a clinically useful tool to identify high-risk patients.

Live imaging and gene expression analysis in zebrafish identifies a link between neutrophils and epithelial to mesenchymal transition

Chronic inflammation is associated with epithelial to mesenchymal transition (EMT) and cancer progression however the relationship between inflammation and EMT remains unclear. Here, we have exploited zebrafish to visualize and quantify the earliest events during epithelial cell transformation induced by oncogenic HRas^V12. Live imaging revealed that expression of HRas^V12 in the epidermis results in EMT and chronic neutrophil and macrophage infiltration. We have developed an in vivo system to probe and quantify gene expression changes specifically in transformed cells from chimeric zebrafish expressing oncogenic HRas^V12 using translating ribosomal affinity purification (TRAP). We found that the expression of genes associated with EMT, including slug, vimentin and mmp9, are enriched in HRas^V12 transformed epithelial cells and that this enrichment requires the presence of neutrophils. An early signal induced by HRas^V12 in epithelial cells is the expression of il-8 (cxcl8) and we found that the chemokine receptor, Cxcr2, mediates neutrophil but not macrophage recruitment to the transformed cells. Surprisingly, we also found a cell autonomous role for Cxcr2 signaling in transformed cells for both neutrophil recruitment and EMT related gene expression associated with Ras transformation. Taken together, these findings implicate both autocrine and paracrine signaling through Cxcr2 in the regulation of inflammation and gene expression in transformed epithelial cells.

The IL-8/CXCR1 axis is associated with cancer stem cell-like properties and correlates with clinical prognosis in human pancreatic cancer cases

CXCR1, a receptor for CXCL8/IL-8, has recently been demonstrated to be associated with cancer stem cell (CSC) populations in certain types of human cancers. However, the effect of CXCR1 on CSC and its prognostic value in human pancreatic cancer remain unknown. In this study, we evaluated the expression of CXCR1 in human pancreatic duct adenocarcinoma (PDAC) and found that positive CXCR1 expression correlated with lymph node metastasis (P = 0.017) and a poor survival rate (HR, 3.748; 95% CI, 1.822 to 7.712; P < 0.001) in patients with PDAC. In addition, we identified significant positive correlations between CXCR1 and CD44 (P = 0.002) and CD133 (P = 0.017). Further functional studies confirmed that IL-8 addition increased sphere formation, CSC populations, and cell invasion of pancreatic cancer cells and that these effects could be reversed by antagonizing CXCR1 with a CXCR1-specific antibody. Therefore, our study demonstrated that the IL-8/CXCR1 axis is associated with the CSC-like properties of pancratic cancer cells and prognosis in human pancreatic cancer. This suggested a way of targeting pancreatic CSCs by disrupting IL-8/CXCR1 axis.

Mesenchymal stem cell-induced doxorubicin resistance in triple negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive histological subtype with limited treatment options and a worse clinical outcome compared with other breast cancer subtypes. Doxorubicin is considered to be one of the most effective agents in the treatment of TNBC. Unfortunately, resistance to this agent is common. In some drug-resistant cells, drug efflux is mediated by adenosine triphosphate-dependent membrane transporter termed adenosine triphosphate-binding cassette (ABC) transporter, which can drive the substrates across membranes against concentration gradient. In the tumor microenvironment, upon interaction with mesenchymal stem cells (MSCs), tumor cells exhibit altered biological functions of certain gene clusters, hence increasing stemness of tumor cells, migration ability, angiogenesis, and drug resistance. In our present study, we investigated the mechanism of TNBC drug resistance induced by adipose-derived MSCs. Upon exposure of TNBC to MSC-secreted conditioned medium (CM), noticeable drug resistance against doxorubicin with markedly increased BCRP protein expression was observed. Intracellular doxorubicin accumulation of TNBC was also decreased by MSC-secreted CM. Furthermore, we found that doxorubicin resistance of TNBC was mediated by IL-8 presented in the MSC-secreted CM. These findings may enrich the list of potential targets for overcoming drug resistance induced by MSCs in TNBC patients.

Zebrafish embryo model of Bartonella henselae infection

Bartonella henselae (Bh) is an emerging zoonotic pathogen that has been associated with a variety of human diseases, including bacillary angiomatosis that is characterized by vasoproliferative tumor-like lesions on the skin of some immunosuppressed individuals. The study of Bh pathogenesis has been limited to in vitro cell culture systems due to the lack of an animal model. Therefore, we wanted to investigate whether the zebrafish embryo could be used to model human infection with Bh. Our data showed that Tg(fli1:egfp)(y1) zebrafish embryos supported a sustained Bh infection for 7 days with >10-fold bacterial replication when inoculated in the yolk sac. We showed that Bh recruited phagocytes to the site of infection in the Tg(mpx:GFP)uwm1 embryos. Infected embryos showed evidence of a Bh-induced angiogenic phenotype and an increase in the expression of genes encoding pro-inflammatory factors and pro-angiogenic markers. However, infection of zebrafish embryos with a deletion mutant in the major adhesin (BadA) resulted in little or no bacterial replication and a diminished host response, providing the first evidence that BadA is critical for in vivo infection. Thus, the zebrafish embryo provides the first practical model of Bh infection that will facilitate efforts to identify virulence factors and define molecular mechanisms of Bh pathogenesis.

The role of chemoattractant receptors in shaping the tumor microenvironment

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics.