Interleukin-1alpha secreted by pancreatic cancer cells promotes angiogenesis and its therapeutic implications

Role of Cytokines and Chemokines in Angiogenesis in a Tumor Context

Simple Summary

Tumor growth in solid cancers requires adequate nutrient and oxygen supply, provided by blood vessels created by angiogenesis. Numerous studies have demonstrated that this mechanism plays a crucial role in cancer development and appears to be a well-defined hallmark of cancer. This process is carefully regulated, notably by cytokines with pro-angiogenic or anti-angiogenic features. In this review, we will discuss the role of cytokines in the modulation of angiogenesis. In addition, we will summarize the therapeutic approaches based on cytokine modulation and their clinical approval.

Abstract

During carcinogenesis, tumors set various mechanisms to help support their development. Angiogenesis is a crucial process for cancer development as it drives the creation of blood vessels within the tumor. These newly formed blood vessels insure the supply of oxygen and nutrients to the tumor, helping its growth. The main factors that regulate angiogenesis are the five members of the vascular endothelial growth factor (VEGF) family. Angiogenesis is a hallmark of cancer and has been the target of new therapies this past few years. However, angiogenesis is a complex phenomenon with many redundancy pathways that ensure its maintenance. In this review, we will first describe the consecutive steps forming angiogenesis, as well as its classical regulators. We will then discuss how the cytokines and chemokines present in the tumor microenvironment can induce or block angiogenesis. Finally, we will focus on the therapeutic arsenal targeting angiogenesis in cancer and the challenges they have to overcome.

10Z‑Hymenialdisine inhibits angiogenesis by suppressing NF‑κB activation in pancreatic cancer cell lines

10Z‑Hymenialdisine is a natural product derived from the marine sponge Axinella carteri. 10Z‑Hymenialdisine has anti‑inflammatory effects exerted through NF‑κB; however, it is unclear whether 10Z‑Hymenialdisine has anti‑angiogenic effects in cancer cells. In the present study, both the anti‑angiogenic and antimetastatic effects of this compound in pancreatic cancer were investigated. It was initially confirmed that 10Z‑Hymenialdisine significantly inhibited the proliferation of pancreatic cancer cells. Next, using both reverse transcription‑quantitative PCR and ELISA, it was demonstrated that 10Z‑Hymenialdisine significantly suppressed the expression of VEGF and IL‑8 mRNAs and proteins in pancreatic cancer. Immunohistochemical analysis revealed that 10Z‑Hymenialdisine inhibited NF‑κB activity in pancreatic cancer cell lines. It was also identified that 10Z‑Hymenialdisine inhibited tube formation in EA.hy926 cells. In vivo, 10Z‑Hymenialdisine significantly inhibited the growth of BxPC‑3 pancreatic cancer cells that were subcutaneously injected into model mice. In conclusion, the present study demonstrated that 10Z‑Hymenialdisine exerted anti‑angiogenic effects by suppressing NF‑κB activity and angiogenic factors, such as VEGF and IL‑8, in pancreatic cancer cell lines. 10Z‑Hymenialdisine has potential applications as a novel therapeutic agent for the treatment of pancreatic cancer.

The role of microenvironment in tumor angiogenesis

Tumor angiogenesis is necessary for the continued survival and development of tumor cells, and plays an important role in their growth, invasion, and metastasis. The tumor microenvironment—composed of tumor cells, surrounding cells, and secreted cytokines—provides a conducive environment for the growth and survival of tumors. Different components of the tumor microenvironment can regulate tumor development. In this review, we have discussed the regulatory role of the microenvironment in tumor angiogenesis. High expression of angiogenic factors and inflammatory cytokines in the tumor microenvironment, as well as hypoxia, are presumed to be the reasons for poor therapeutic efficacy of current anti-angiogenic drugs. A combination of anti-angiogenic drugs and antitumor inflammatory drugs or hypoxia inhibitors might improve the therapeutic outcome.

Role of Matrix Metalloproteinases in Angiogenesis and Cancer

During angiogenesis, new vessels emerge from existing endothelial lined vessels to promote the degradation of the vascular basement membrane and remodel the extracellular matrix (ECM), followed by endothelial cell migration, and proliferation and the new generation of matrix components. Matrix metalloproteinases (MMPs) participate in the disruption, tumor neovascularization, and subsequent metastasis while tissue inhibitors of metalloproteinases (TIMPs) downregulate the activity of these MMPs. Then, the angiogenic response can be directly or indirectly mediated by MMPs through the modulation of the balance between pro- and anti-angiogenic factors. This review analyzes recent knowledge on MMPs and their participation in angiogenesis.

IL-1 Family Cytokine Regulation of Vascular Permeability and Angiogenesis

The IL-1 family of cytokines are well-known for their primary role in initiating inflammatory responses both in response to and acting as danger signals. It has long been established that IL-1 is capable of simultaneously regulating inflammation and angiogenesis, indeed one of IL-1's earliest names was haemopoeitn-1 due to its pro-angiogenic effects. Other IL-1 family cytokines are also known to have roles in mediating angiogenesis, either directly or indirectly via induction of proangiogenic factors such as VEGF. Of note, some of these family members appear to have directly opposing effects in different tissues and pathologies. Here we will review what is known about how the various IL-1 family members regulate vascular permeability and angiogenic function in a range of different tissues, and describe some of the mechanisms employed to achieve these effects.

The role of interleukin-1 in general pathology

Interleukin-1, an inflammatory cytokine, is considered to have diverse physiological functions and pathological significances and play an important role in health and disease. In this decade, interleukin-1 family members have been expanding and evidence is accumulating that highlights the importance of interleukin-1 in linking innate immunity with a broad spectrum of diseases beyond inflammatory diseases. In this review, we look back on the definition of "inflammation" in traditional general pathology and discuss new insights into interleukin-1 in view of its history and the molecular bases of diseases, as well as current progress in therapeutics.

Xanthohumol inhibits angiogenesis by suppressing nuclear factor-κB activation in pancreatic cancer

Xantohumol, a prenylated chalcone from hops (Humulus lupulus L.), has been shown to inhibit proliferation in some cancers. However, little is known regarding the effects of xanthohumol in pancreatic cancer. We have previously reported that activation of the transcription factor nuclear factor-κB (NF-κB) plays a key role in angiogenesis in pancreatic cancer. In this study, we investigated whether xanthohumol inhibited angiogenesis by blocking NF-κB activation in pancreatic cancer in vitro and in vivo. We initially confirmed that xanthohumol significantly inhibited proliferation and NF-κB activation in pancreatic cancer cell lines. Next, we demonstrated that xanthohumol significantly suppressed the expression of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) at both the mRNA and protein levels in pancreatic cancer cell lines. We also found that coculture with BxPC-3 cells significantly enhanced tube formation in human umbilical vein endothelial cells, and treatment with xanthohumol significantly blocked this effect. In vivo, the volume of BxPC-3 subcutaneous xenograft tumors was significantly reduced in mice treated with weekly intraperitoneal injections of xanthohumol. Immunohistochemistry revealed that xanthohumol inhibited Ki-67 expression, CD31-positive microvessel density, NF-κB p65 expression, and VEGF and IL-8 levels. Taken together, these results showed, for the first time, that xanthohumol inhibited angiogenesis by suppressing NF-κB activity in pancreatic cancer. Accordingly, xanthohumol may represent a novel therapeutic agent for the management of pancreatic cancer.

Structural basis for IL-1α recognition by a modified DNA aptamer that specifically inhibits IL-1α signaling

IL-1α is an essential cytokine that contributes to inflammatory responses and is implicated in various forms of pathogenesis and cancer. Here we report a naphthyl modified DNA aptamer that specifically binds IL-1α and inhibits its signaling pathway. By solving the crystal structure of the IL-1α/aptamer, we provide a high-resolution structure of this critical cytokine and we reveal its functional interaction interface with high-affinity ligands. The non-helical aptamer, which represents a highly compact nucleic acid structure, contains a wealth of new conformational features, including an unknown form of G-quadruplex. The IL-1α/aptamer interface is composed of unusual polar and hydrophobic elements, along with an elaborate hydrogen bonding network that is mediated by sodium ion. IL-1α uses the same interface to interact with both the aptamer and its cognate receptor IL-1RI, thereby suggesting a novel route to immunomodulatory therapeutics.

The cytokine interleukin 1α (IL-1α) plays an important role in inflammatory processes. Here the authors use SELEX to generate a modified DNA aptamer which specifically binds IL-1α, present the structure of the IL-1α/aptamer complex and show that this aptamer inhibits the IL-1α signaling pathway.

Inhibition of EGF expression and NF-κB activity by treatment with quercetin leads to suppression of angiogenesis in nasopharyngeal carcinoma

The present study was performed to investigate the effect of quercetin on nasopharyngeal carcinoma (NPC) angiogenesis. The real-time RT-PCR and enzyme-linked immunosorbent assays (ELISA) were performed to analyze the expression levels of vascular endothelial growth factor (VEGF) in nasopharyngeal carcinoma cell lines prior to and after the quercetin treatment. Effect of quercetin on the rate of cell proliferation was measured by MTT assay. It was observed that quercetin treatment at a concentration of 10 mg/mL reduced the rate of NPC039 cell viability to 36% compared to control after 24 h. The expression of VEGF and activity of NF-κB was also markedly reduced. The ability of tube formation in HUVECs was inhibited significantly on exposure to quercetin compared to the untreated cells. Therefore, quercetin plays an important role in the inhibition of NPC039 nasopharyngeal carcinoma and can be of therapeutic importance.

Cytokine Regulation of Metastasis and Tumorigenicity

The human body combats infection and promotes wound healing through the remarkable process of inflammation. Inflammation is characterized by the recruitment of stromal cell activity including recruitment of immune cells and induction of angiogenesis. These cellular processes are regulated by a class of soluble molecules called cytokines. Based on function, cell target, and structure, cytokines are subdivided into several classes including: interleukins, chemokines, and lymphokines. While cytokines regulate normal physiological processes, chronic deregulation of cytokine expression and activity contributes to cancer in many ways. Gene polymorphisms of all types of cytokines are associated with risk of disease development. Deregulation RNA and protein expression of interleukins, chemokines, and lymphokines have been detected in many solid tumors and hematopoetic malignancies, correlating with poor patient prognosis. The current body of literature suggests that in some tumor types, interleukins and chemokines work against the human body by signaling to cancer cells and remodeling the local microenvironment to support the growth, survival, and invasion of primary tumors and enhance metastatic colonization. Some lymphokines are downregulated to suppress tumor progression by enhancing cytotoxic T cell activity and inhibiting tumor cell survival. In this review, we will describe the structure/function of several cytokine families and review our current understanding on the roles and mechanisms of cytokines in tumor progression. In addition, we will also discuss strategies for exploiting the expression and activity of cytokines in therapeutic intervention.

The TGFβ-SMAD3 pathway inhibits IL-1α induced interactions between human pancreatic stellate cells and pancreatic carcinoma cells and restricts cancer cell migration

BACKGROUND

The most abundant cells in the extensive desmoplastic stroma of pancreatic adenocarcinomas are the pancreatic stellate cells, which interact with the carcinoma cells and strongly influence the progression of the cancer. Tumor stroma interactions induced by IL-1α/IL-1R1 signaling have been shown to be involved in pancreatic cancer cell migration. TGFβ and its receptors are overexpressed in pancreatic adenocarcinomas. We aimed at exploring TGFβ and IL-1α signaling and cross-talk in the stellate cell cancer cell interactions regulating pancreatic adenocarcinoma cell migration.

METHODS

Human pancreatic stellate cells were isolated from surgically resected pancreatic adenocarcinomas and cultured in the presence of TGFβ or pancreatic adenocarcinoma cell lines. The effects of TGFβ were blocked by inhibitors or amplified by silencing the endogenous inhibitor of SMAD signaling, SMAD7. Pancreatic stellate cell responses to IL-1α or to IL-1α-expressing pancreatic adenocarcinoma cells (BxPC-3) were characterized by their ability to stimulate migration of cancer cells in a 2D migration model.

RESULTS

In pancreatic stellate cells, IL-1R1 expression was found to be down-regulated by TGFβ and blocking of TGFβ signaling re-established the expression. Endogenous inhibition of TGFβ signaling by SMAD7 was found to correlate with the levels of IL-1R1, indicating a regulatory role of SMAD7 in IL-1R1 expression. Pancreatic stellate cells cultured in the presence of IL-1α or in co-cultures with BxPC-3 cells enhanced the migration of cancer cells. This effect was blocked after treatment of the pancreatic stellate cells with TGFβ. Silencing of stellate cell expression of SMAD7 was found to suppress the levels of IL-1R1 and reduce the stimulatory effects of IL-1α, thus inhibiting the capacity of pancreatic stellate cells to induce cancer cell migration.

CONCLUSIONS

TGFβ signaling suppressed IL-1α mediated pancreatic stellate cell induced carcinoma cell migration. Depletion of SMAD7 upregulated the effects of TGFβ and reduced the expression of IL-1R1, leading to inhibition of IL-1α induced stellate cell enhancement of carcinoma cell migration. SMAD7 might represent a target for inhibition of IL-1α induced tumor stroma interactions.

An insertion/deletion polymorphism at miRNA-122 binding site in the IL1A is associated with a reduced risk of cervical squamous cell carcinoma

OBJECTIVE

Previous studies have shown that miRNA plays a key role in cervical carcinogenesis. Interleukin (IL)-1α can promote tumor growth, invasion, migration, and angiogenesis. An insertion/deletion polymorphism (rs3783553) in the IL1A 3' untranslated region may disrupt a binding site for miR-122 and miR-378 and thus change the transcription of IL-1α. The purpose of this study was to evaluate the association between the rs3783553 polymorphism and the risk of cervical squamous cell carcinoma (CSCC).

METHODS

Polymerase chain reaction was used to genotype the IL1A rs3783553 polymorphism in 235 patients with CSCC and 326 controls.

RESULTS

We found that the ins/ins genotype had a decreased risk to develop CSCC (odds ratio [OR]=0.48, 95% confidence interval [CI], 0.25-0.95). However, no significant association was observed between the IL1A rs3783553 genotype and clinical features.

CONCLUSION

These findings indicate that the IL1A rs3783553 polymorphism may be associated with the etiology of CSCC.

Interleukin-1 receptor antagonist (IL1RN) is associated with suppression of early carcinogenic events in human oral malignancies

Inflammatory abnormalities have been implicated in the pathogenesis of various human diseases, including cancer. Interleukin-1 receptor antagonist (IL1RN) is a potent anti-inflammatory molecule that modulates the biological activity of the proinflammatory cytokine, interleukin-1. The aim of this study was to examine the expression of IL1RN in oral squamous cell carcinomas (OSCCs), and to determine its clinical significance. Expression levels of IL1RN in matched normal and tumor specimens from 39 OSCCs were evaluated using real-time quantitative polymerase chain reaction methods, and immunohistochemical analysis. Protein expression of IL1RN was also examined in 18 oral premalignant lesions (OPLs). Expression of IL1RN mRNA was significantly downregulated in OSCCs compared with normal tissues. Decreased expression of IL1RN protein was also observed in OPLs and OSCCs. The IL1RN expression level was lower in the OPL cases with severe dysplasia compared to those with mild/moderate dysplasia. Significantly downregulated IL1RN expression was observed in all OSCC lesion sites examined when compared with the matched normal tissues. However, the decreased level of IL1RN expression did not correspond with tumor progression. Noteworthy, IL1RN expression was higher in the advanced OSCC cases (T3/T4) compared to early cases (T1/T2). Among OSCC samples, relatively higher IL1RN expression was associated with active tumor development in the OSCCs occurring in the buccal mucosa, oral floor, fauces and gingiva, but not the tongue. These data suggest that IL1RN may exhibit opposing characteristics in oral malignancies depending on the stage of cancer development, suppressing early carcinogenic events, yet promoting tumor development in some lesion sites. Thus, IL1RN could represent a reliable biomarker for the early diagnosis of OSCCs. Furthermore, IL1RN may possess unknown and complex functions in the developed OSCC.

Reciprocal interaction between carcinoma-associated fibroblasts and squamous carcinoma cells through interleukin-1α induces cancer progression

Crosstalk between cancer cells and carcinoma-associated fibroblasts (CAFs) has earned recognition as an interaction that plays a pivotal role in carcinogenesis. Thus, we attempted to clarify whether increase in the level of CAFs promotes cancer progression by proportionally enhancing the interaction between cancer cells and CAFs. We first analyzed clinical correlation between the levels of fibroblasts and cancer progression and found that the level of CAFs made a noticeable difference on the prognosis of patients with oral squamous cell carcinoma (OSCC). In vivo animal study also demonstrated that tumor volume depended on the dose of CAFs that was co-injected with OSCC cells. The same tendency was observed in an in vitro study. We also found that interleukin-1α (IL-1α) secreted from OSCC cells had dual effects on CAFs: IL-1α not only promoted the proliferation of CAFs but also upregulated the secretion of cytokines in CAFs such as CCL7, CXCL1, and IL-8. The induction activity of cytokine secretion by IL-1α surpassed that of proliferation in OSCC cells. In summary, we unraveled an important interactive mechanism of carcinogenesis: IL-1α released from carcinoma stimulates the proliferation of CAFs and the simultaneous increase in cytokine secretion from CAFs promotes cancer progression in human OSCC. On the basis of these findings, we propose that the level of CAFs is eligible for being selected as a prognostic factor that will be useful in routine diagnosis. We also propose that blockage of reciprocal interaction between cancer cells and CAFs will provide an insight for developing novel chemotherapeutic strategy.

Association of an insertion/deletion polymorphism in IL1A 3'-UTR with risk for cervical carcinoma in Chinese Han Women

Emerging evidence has demonstrated that polymorphisms of interleukin-1 (IL-1) may be involved in human tumorigenesis by regulating the production of this cytokine. Previous studies have investigated the association between two genetic variants (rs3783553 and rs17561) of IL1A and many diseases. The present study was conducted to evaluate whether these two variants are associated with cervical carcinoma (CC). These two polymorphisms were genotyped in 319 CC patients and 424 healthy controls by polymerase chain reaction polyacrylamide gel electrophoresis (PCR-PAGE) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Significantly reduced CC risk was observed to be associated with the insertion allele of rs3783553 (P=0.014, OR=0.71, 95% CI=0.57-0.88). Stratification analysis based on different certain clinical features showed that patients with the heterozygous genotype were associated with a reduced predisposition advancing to clinical stage II-III or developing non-squamous cell carcinoma. Furthermore, patients with the insertion homozygous genotype were also associated with a reduced risk to have a poor tumor differentiation. No significant association was observed between rs17561 and CC. The present study provided evidence that the rs3783553 in IL1A 3'-UTR is inversely associated with CC risk, suggesting an important role IL-1α may play in cervical carcinogenesis.

MABp1, a first-in-class true human antibody targeting interleukin-1α in refractory cancers: an open-label, phase 1 dose-escalation and expansion study

BACKGROUND

Inflammation is an important feature of the malignant phenotype and promotes angiogenesis, tumour invasiveness, metastases, and cachexia. We used a first-in-class, monoclonal antibody (MABp1) cloned from a human being to target interleukin-1α, a mediator of chronic inflammation. We aimed to assess the safety and tolerability of MABp1 for interleukin-1α blockade in a refractory cancer population.

METHODS

We did an open-label, dose-escalation, and phase 1 study of MABp1 in adults with metastatic cancer at the MD Anderson Clinical Center for Targeted Therapy (Houston, TX, USA). We used a standard 3+3 design to identify the maximum tolerated dose. Patients received MABp1 intravenously once every 3 weeks through four dose levels: 0.25 mg/kg, 0.75 mg/kg, 1.25 mg/kg, and 3.75 mg/kg. After the dose-escalation phase, a second dosing arm was started with dosing every 2 weeks at the maximum tolerated dose. The primary objectives were safety, tolerability, characterisation of the pharmacokinetic profile, and identification of the recommended phase 2 dose. Secondary endpoints included pharmacodynamic effects and antitumour activity. All patients who received at least one dose of MABp1 were included in the safety analyses. This trial is registered with ClinicalTrials.gov, NCT01021072.

FINDINGS

Between March 15, 2010, and July 30, 2012, 52 patients with metastatic cancer (18 tumour types) received anti-interleukin-1α monotherapy in dose-escalation and expansion groups. MABp1 was well tolerated, with no dose-limiting toxicities or immunogenicity. Thus, the recommended phase 2 dose was concluded to be 3.75 mg/kg every 2 weeks. Pharmacokinetic data were consistent at all dose levels and showed no evidence of accumulation or increased clearance of MABp1 at increasing doses. For 42 assessable patients, median plasma interleukin-6 concentrations had decreased from baseline to week 8 by a median of 2.7 pg/mL (IQR -12.6 to 3.0; p=0.08). Of the 34 patients restaged, one patient had a partial response and ten had stable disease. 30 patients were assessable for change in lean body mass, which increased by a mean of 1.02 kg (SD 2.24; p=0.02) between baseline and week 8. The most common adverse events possibly related to the study drug were proteinuria (n=11; 21%), nausea (7; 13%), and fatigue (7; 13%). The most frequent grade 3-4 adverse events (regardless of relation to treatment) were fatigue (3; 6%), dyspnoea (2; 4%), and headache (2; 4%). Two patients (4%) had grade 5 events (death due to disease progression), which were unrelated to treatment.

INTERPRETATION

MABp1 was well tolerated, no dose-limiting toxicities were experienced in this study, and disease control was observed. Further study of MABp1 anti-interleukin-1α antibody therapy for advanced stage cancer is warranted.

Zerumbone inhibits angiogenesis by blocking NF-κB activity in pancreatic cancer

OBJECTIVES

Because angiogenesis is essential for tumor growth and metastasis, the development of antiangiogenic agents is an urgent issue in cancer treatment. Zerumbone, a component of subtropical ginger, has been shown to exhibit anticancer activities in various cancer cells; however, little is known about its biological mechanisms against angiogenesis in pancreatic cancer (PaCa). Here, we evaluated the effects of zerumbone on PaCa angiogenesis.

METHODS

The cytotoxicity of zerumbone in PaCa was measured using premix WST-1 cell proliferation assays. The influence of zerumbone on the angiogenic factors vascular endothelial growth factor and interleukin 8 was measured using the reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assays. Changes in nuclear factor-κB (NF-κB) activities were measured using NF-κB transcription factor assays. We also examined the effects of zerumbone on PaCa-induced angiogenesis using angiogenesis assays.

RESULTS

Zerumbone inhibited mRNA expression and protein secretion of angiogenic factors and NF-κB activity. Tube formation in human umbilical vein endothelial cells was enhanced by coculture with PaCa cells, and these enhancements were significantly inhibited by zerumbone treatment.

CONCLUSIONS

Zerumbone blocked the PaCa-associated angiogenesis through the inhibition of NF-κB and NF-κB-dependent proangiogenic gene products.

The role IL-1 in tumor-mediated angiogenesis

Tumor angiogenesis is one of the hallmarks of tumor progression and is essential for invasiveness and metastasis. Myeloid inflammatory cells, such as immature myeloid precursor cells, also termed myeloid-derived suppressor cells (MDSCs), neutrophils, and monocytes/macrophages, are recruited to the tumor microenvironment by factors released by the malignant cells that are subsequently “educated” in situ to acquire a pro-invasive, pro-angiogenic, and immunosuppressive phenotype. The proximity of myeloid cells to endothelial cells (ECs) lining blood vessels suggests that they play an important role in the angiogenic response, possibly by secreting a network of cytokines/chemokines and inflammatory mediators, as well as via activation of ECs for proliferation and secretion of pro-angiogenic factors. Interleukin-1 (IL-1) is an “alarm,” upstream, pro-inflammatory cytokine that is generated primarily by myeloid cells. IL-1 initiates and propagates inflammation, mainly by inducing a local cytokine network and enhancing inflammatory cell infiltration to affected sites and by augmenting adhesion molecule expression on ECs and leukocytes. Pro-inflammatory mediators were recently shown to play an important role in tumor-mediated angiogenesis and blocking their function may suppress tumor progression. In this review, we summarize the interactions between IL-1 and other pro-angiogenic factors during normal and pathological conditions. In addition, the feasibility of IL-1 neutralization approaches for anti-cancer therapy is discussed.

Mechanism of pro-tumorigenic effect of BMP-6: neovascularization involving tumor-associated macrophages and IL-1a

INTRODUCTION. Overexpression of bone morphogenetic protein-6 (BMP-6) has been reported in human prostate cancer tissues. Previously we have demonstrated that BMP-6 enhances prostate cancer growth in mice and not in tissue culture. Herein, we have investigated the mechanism of BMP-6’s pro-tumorigenic effect in prostate cancer. METHODS. Tramp C2 murine and LNCaP human prostate cancer cell lines were co-cultured with RAW 264.7 and THP-1 cells, respectively. IL-1a knockout mice were used to confirm the role of BMP-6/IL-1a loop in vivo. Lastly, conditional macrophage null mice cd11b-DTR was used. RESULTS. The results demonstrated that BMP-6 induced the expression of IL-1a in macrophages via a cross-talk between NF-kB1 p50 and Smad1. When endothelial cells were treated with conditioned media harvested from macrophages incubated with BMP-6, tube formation was detected. In the presence of IL-1a neutralizing antibody, endothelial tube formation was blocked. In vivo, tumor growth and neovascularization decreased significantly when BMP-6 was expressed in IL-1a knockout and conditional macrophage-null mice. CONCLUSIONS. Prostate cancer-derived BMP-6 stimulates tumor-associated macrophages to produce IL-1a through a crosstalk between Smad1 and NF-kB1; IL-1a, in turn, promotes angiogenesis and prostate cancer growth.

The senescence-associated secretory phenotype promotes benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is characterized by increased tissue mass in the transition zone of the prostate, which leads to obstruction of urine outflow and considerable morbidity in a majority of older men. Senescent cells accumulate in human tissues, including the prostate, with increasing age. Expression of proinflammatory cytokines is increased in these senescent cells, a manifestation of the senescence-associated secretory phenotype. Multiplex analysis revealed that multiple cytokines are increased in BPH, including GM-CSF, IL-1α, and IL-4, and that these are also increased in senescent prostatic epithelial cells in vitro. Tissue levels of these cytokines were correlated with a marker of senescence (cathepsin D), which was also strongly correlated with prostate weight. IHC analysis revealed the multifocal epithelial expression of cathepsin D and coexpression with IL-1α in BPH tissues. In tissue recombination studies in nude mice with immortalized prostatic epithelial cells expressing IL-1α and prostatic stromal cells, both epithelial and stromal cells exhibited increased growth. Expression of IL-1α in prostatic epithelial cells in a transgenic mouse model resulted in increased prostate size and bladder obstruction. In summary, both correlative and functional evidence support the hypothesis that the senescence-associated secretory phenotype can promote the development of BPH, which is the single most common age-related pathology in older men.

Zerumbone inhibits tumor angiogenesis via NF-κB in gastric cancer

Zerumbone derived from a subtropical ginger, Zingiber zerumbet Smith, was previously reported to have antitumor growth and anti-inflammatory properties in some types of cancer. However, the effects of zerumbone against cancer angiogenesis have not been fully elucidated. In this study, we clarified the role of zerumbone in gastric cancer angiogenesis. We examined the expression of vascular endothelial growth factor (VEGF) in gastric cancer cell lines both in the basal state and following zerumbone treatment by real-time RT-PCR and enzyme-linked immunosorbent assay (ELISA). Changes in gastric cancer cell proliferation in response to zerumbone treatment were measured by WST-1 assay. Additionally, the effects of zerumbone on NF-κB activity were examined in AGS cells. Finally, the effects of zerumbone on angiogenesis in AGS cells were measured by in vitro angiogenesis assay in which human umbilical vein endothelial cells (HUVECs) and fibroblasts were cocultured with AGS cells. Among the 6 gastric cancer cell lines tested, AGS cells exhibited the highest expression of VEGF. Cell proliferation, VEGF expression and NF-κB activity in AGS cells were all significantly inhibited by zerumbone. Moreover, the tube formation area of HUVECs was increased by coculture with AGS cells, and this effect was inhibited by zerumbone. Both VEGF expression and NF-κB activity in AGS cells were reduced by treatment with zerumbone, thereby inhibiting angiogenesis. Thus, zerumbone may become a new anti-angiogenic and antitumor drug in the treatment of gastric cancer.

IL-32 promotes angiogenesis

IL-32 is a multifaceted cytokine with a role in infections, autoimmune diseases, and cancer, and it exerts diverse functions, including aggravation of inflammation and inhibition of virus propagation. We previously identified IL-32 as a critical regulator of endothelial cell (EC) functions, and we now reveal that IL-32 also possesses angiogenic properties. The hyperproliferative ECs of human pulmonary arterial hypertension and glioblastoma multiforme exhibited a markedly increased abundance of IL-32, and, significantly, the cytokine colocalized with integrin αVβ3. Vascular endothelial growth factor (VEGF) receptor blockade, which resulted in EC hyperproliferation, increased IL-32 three-fold. Small interfering RNA-mediated silencing of IL-32 negated the 58% proliferation of ECs that occurred within 24 h in scrambled-transfected controls. Reduction of IL-32 neither affected apoptosis (insignificant changes in Bak-1, Bcl-2, Bcl-xL, lactate dehydrogenase, annexin V, and propidium iodide) nor VEGF or TGF-β levels, but siIL-32-transfected adult and neonatal ECs produced up to 61% less NO, IL-8, and matrix metalloproteinase-9, and up to 3-fold more activin A and endostatin. In coculture-based angiogenesis assays, IL-32γ dose-dependently increased tube formation up to 3-fold; an αVβ3 inhibitor prevented this activity and reduced IL-32γ-induced IL-8 by 85%. In matrigel plugs loaded with IL-32γ, VEGF, or vehicle and injected into live mice, we observed the anticipated VEGF-induced increase in neocapillarization (8-fold versus vehicle), but unexpectedly, IL-32γ was equally angiogenic. A second signal such as IFN-γ was required to render cells responsive to exogenous IL-32γ; importantly, this was confirmed using a completely synthetic preparation of IL-32γ. In summary, we add angiogenic properties that are mediated by integrin αVβ3 but VEGF-independent to the portfolio of IL-32, implicating a role for this versatile cytokine in pulmonary arterial hypertension and neoplastic diseases.

Interleukin-1α

Although the IL-1α molecule has long been recognized, information about its distinct role in various diseases is limited, since most clinical studies have focused on the role of IL-1β. Despite triggering the same IL-1 receptor as does IL-1β, there is, however, a distinct role for IL-1α in some inflammatory diseases. IL-1α is a unique cytokine since it is constitutively present intracellularly in nearly all resting non-hematopoietic cells in health as well as being up-regulated during hypoxia. During cell necrosis, IL-1α functions as an alarm molecule and thus plays a critical role early in inflammation. Following its release from damage tissue cells, IL-1α mediates neutrophil recruitment to the site of injury, inducing IL-1β, other cytokines and chemokines from surrounding resident cells. Another unique attribute of IL-1α is its nuclear localization sequence present in the N-terminal half of the precursor termed the propiece. The IL-1α propiece translocates into the nucleus and participates in the regulation of transcription. Therefore, IL-1α, like IL-1 family members IL-33 and IL-37, is a 'dual-function' cytokine binding to chromatin as well as to its cell surface receptor. Some cancer cells can express membrane IL-1α, which can increase immunogenicity of tumor cells and serve in anti-tumor immune surveillance and tumor regression. However, in the tumor microenvironment, precursor IL-1α released from dying tumor cells is inflammatory and, similar to IL-1β, increases tumor invasiveness and angiogenesis.

IL-1α expression in pancreatic ductal adenocarcinoma affects the tumor cell migration and is regulated by the p38MAPK signaling pathway

The interplay between the tumor cells and the surrounding stroma creates inflammation, which promotes tumor growth and spread. The inflammation is a hallmark for pancreatic adenocarcinoma (PDAC) and is to high extent driven by IL-1α. IL-1α is expressed and secreted by the tumor cells and exerting its effect on the stroma, i.e. cancer associated fibroblasts (CAF), which in turn produce massive amount of inflammatory and immune regulatory factors. IL-1 induces activation of transcription factors such as nuclear factor-κβ (NF-κβ), but also activator protein 1 (AP-1) via the small G-protein Ras. Dysregulation of Ras pathways are common in cancer as this oncogene is the most frequently mutated in many cancers. In contrast, the signaling events leading up to the expression of IL-1α by tumor cells are not well elucidated. Our aim was to examine the signaling cascade involved in the induction of IL-1α expression in PDAC. We found p38MAPK, activated by the K-Ras signaling pathway, to be involved in the expression of IL-1α by PDAC as blocking this pathway decreased both the gene and protein expression of IL-1α. Blockage of the P38MAPK signaling in PDAC also dampened the ability of the tumor cell to induce inflammation in CAFs. In addition, the IL-1α autocrine signaling regulated the migratory capacity of PDAC cells. Taken together, the blockage of signaling pathways leading to IL-1α expression and/or neutralization of IL-1α in the PDAC microenvironment should be taken into consideration as possible treatment or complement to existing treatment of this cancer.

The immune network in pancreatic cancer development and progression

The presence of stromal desmoplasia is a hallmark of spontaneous pancreatic ductal adenocarcinoma, forming a unique microenvironment that comprises many cell types. Only recently, the immune system has entered the pathophysiology of pancreatic ductal adenocarcinoma development. Tumor cells in the pancreas seem to dysbalance the immune system, thus facilitating spontaneous cancer development. This review will try to assemble all relevant data to demonstrate the implications of the immune network on spontaneous cancer development.

Targeting the cancer-stroma interaction: a potential approach for pancreatic cancer treatment

Recent studies have demonstrated that the interaction between the cancer and the stroma, play a key role in the development of pancreatic cancer. The desmoplasia, which consists of fibroblasts, pancreatic stellate cells, lymphatic and vascular endothelial cells, immune cells, pathologic increased nerves, and the extracellular matrix (ECM), creates a complex tumor microenvironment that promotes pancreatic cancer development, invasion, metastasis, and resistance to chemotherapy. Thus, the potential approach for targeting the components of this desmoplastic reaction or the pancreatic tumor microenvironment might represent a novel therapeutic approach to advanced pancreatic carcinoma. Novel therapies that target on the pancreatic tumor microenvironment should become one of the more effective treatments for pancreatic cancer.

Interleukin 1α sustains the expression of inflammatory factors in human pancreatic cancer microenvironment by targeting cancer-associated fibroblasts

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) is dynamic, with an extensive interaction between the stroma and tumor cells. The aim of this study was to delineate the cross talk between PDAC and cancer-associated fibroblasts (CAFs), with a focus on the mechanism creating the chronic inflammatory tumor milieu. We assessed the effects of the cross talk between PDAC and CAF cell lines on the creation and sustenance of the inflammatory tumor microenvironment in pancreatic cancer. The coculture of PDAC and CAF cell lines enhanced the levels of inflammatory factors including IL-1α, IL-6, CXCL8, VEGF-A, CCL20, and COX-2. CAFs were superior to tumor cells regarding the production of most inflammatory factors, and tumor cell-associated IL-1α was established as the initiator of the enhanced production of inflammatory factors through the binding of IL-1α to IL-1 receptor 1 (IL-1R1) expressed predominantly by CAFs. Furthermore, we found a correlation between IL-1α and CXCL8 expression levels in PDAC tissues and correlation between IL-1α expression and the clinical outcome of the patients. This confirmed an important role for the IL-1 signaling cascade in the creation and sustenance of a tumor favorable microenvironment. Neutralization of the IL-1α signaling efficiently diminished the cross talk-induced production of inflammatory factors. These data suggest that the cross talk between PDAC cells and the main stroma cell type, i.e. CAFs, is one essential factor in the formation of the inflammatory tumor environment, and we propose that neutralization of the IL-1α signaling might be a potential therapy for this cancer.

IGF-1 mediates PTEN suppression and enhances cell invasion and proliferation via activation of the IGF-1/PI3K/Akt signaling pathway in pancreatic cancer cells

BACKGROUND

Type-1 insulin-like growth factor (IGF-1) up-regulates cell proliferation and invasiveness through activation of PI3K/Akt signaling pathway. IGF-1 also down-regulates the tumor suppressor chromosome 10 (PTEN). We investigated the mechanism by which IGF-1 affects cell proliferation and invasion by suppression of PTEN phosphorylation and interaction with PI3K/PTEN/Akt/NF-small ka, CyrillicB signaling pathway in pancreatic cancer.

MATERIALS AND METHODS

The expression of IGF-1 receptor (IGF-1R) and PTEN in five pancreatic cancer cell lines was determined by RT-PCR and Western blot. Proliferation and invasion were investigated by WST-1 assay and Matrigel-double chamber assay. Pancreatic cancer cells were transfected with PTEN siRNA to investigate which signaling pathway correlates in regulation of cancer cell proliferation and invasion.

RESULTS

Five pancreatic cancer cell lines expressed PTEN and IGF-1R in mRNA and protein levels. Suppression of PTEN phosphorylation strongly enhanced cell proliferation and invasion stimulated with IGF-1 via activation of PI3K/Akt/NF-small ka, CyrillicB signaling pathway. In addition, knockdown of PTEN by siRNA transfection also enhanced activation of PI3K/Akt/NF-small ka, CyrillicB pathway, subsequently up-regulating cell invasiveness and proliferation.

CONCLUSIONS

The IGF-1/PI3K/PTEN/Akt/NF-small ka, CyrillicB cascade may be a key pathway stimulating metastasis of pancreatic cancer cells. We suggest that interfering with the functions of IGF-1/PI3K/Akt/NF-small ka, CyrillicB might be a novel therapeutic approach to inhibit aggressive spread of pancreatic cancer.

Secreted interleukin-1alpha induces a metastatic phenotype in pancreatic cancer by sustaining a constitutive activation of nuclear factor-kappaB

Transcription factor nuclear factor-kappaB (NF-kappaB) is constitutively activated in most pancreatic cancer tissues and cell lines but not in normal pancreas nor in immortalized/nontumorigenic human pancreatic ductal epithelial cells. Inhibition of constitutive NF-kappaB activation in pancreatic cancer cell lines suppresses tumorigenesis and tumor metastasis. Recently, we identified autocrine secretion of proinflammatory cytokine interleukin (IL)-1alpha as the mechanism of constitutive NF-kappaB activation in metastatic pancreatic cancer cell lines. However, the role of IL-1alpha in determining the metastatic potential of pancreatic tumor remains to be further investigated. In the current study, we stably expressed IL-1alpha in the nonmetastatic, IL-1alpha-negative MiaPaCa-2 cell lines. Our results showed that the secretion of IL-1alpha in MiaPaCa-2 cells constitutively activated NF-kappaB and increased the expression of NF-kappaB downstream genes involved in the different steps of the metastatic cascade, such as urokinase-type plasminogen activator, vascular endothelial growth factor, and IL-8. MiaPaCa-2/IL-1alpha cells showed an enhanced cell invasion in vitro compared with parental MiaPaCa-2 cells and induced liver metastasis in an orthotopic mouse model. The metastatic phenotype induced by IL-1alpha was inhibited by the expression of phosphorylation-defective IkappaB (IkappaB S32, 36A), which blocked NF-kappaB activation. Consistently, silencing the expression of IL-1alpha by short hairpin RNA in the highly metastatic L3.6pl pancreatic cancer cells completely suppressed their metastatic spread. In summary, these findings showed that IL-1alpha plays key roles in pancreatic cancer metastatic behavior through the constitutive activation of NF-kappaB. Our findings further support the possible link between inflammation and cancer and suggest that IL-1alpha may be a potential therapeutic target for treating pancreatic adenocarcinoma.