Three-month life expectancy as inclusion criterion for clinical trials in advanced pancreatic cancer: is it really a valid tool for patient selection?

PURPOSE

To analyze the 3-month life expectancy rate in pancreatic cancer (PC) patients treated within prospective trials from the German AIO study group.

PATIENTS AND METHODS

A pooled analysis was conducted for patients with advanced PC that were treated within five phase II/III studies conducted between 1997 and 2017 (Gem/Cis, Ro96, RC57, ACCEPT, RASH). The primary goal for the current report was to identify the actual 3-month survival rate, a standard inclusion criterion in oncology trials.

RESULTS

Overall, 912 patients were included, 83% had metastatic and 17% locally advanced PC; the estimated median overall survival (OS) was 7.1 months. Twenty-one percent of the participants survived < 3 months, with a range from 26% in RC57 to 15% in RASH. Significant predictors for not reaching 3-month OS were > 1 previous treatment line (p < 0.001) and performance status (p < 0.001).

CONCLUSIONS

Despite the definition of a life expectancy of > 3 months as a standard inclusion criterion in clinical trials for advanced PC, a significant proportion of study patients does not survive > 3 months.

TRIAL REGISTRATION NUMBERS

NCT00440167 (AIO-PK0104), NCT01729481 (RASH), NCT01728818 (ACCEPT).

Changes over time in the course of advanced pancreatic cancer treatment with systemic chemotherapy: a pooled analysis of five clinical trials from two decades of the German AIO study group

BACKGROUND

Over the past two decades, our group has conducted five multicenter trials focusing on first-line systemic therapy for patients with advanced pancreatic cancer. The current pooled analysis was designed to evaluate prognosis over time and the impact of clinical characteristics on survival.

PATIENTS AND METHODS

Individual patient data were derived from five prospective, controlled, multicenter trials conducted by the 'Arbeitsgemeinschaft Internistische Onkologie' (AIO): 'Gem/Cis', 'Ro96', 'RC57', 'ACCEPT' and 'RASH', which recruited patients between December 1997 and January 2017.

RESULTS

Overall, 912 patients were included. The median overall survival (OS) for all assessable patients was 7.1 months. OS significantly improved over time, with a median OS of 8.6 months for patients treated from 2012 to 2017 compared with 7.0 months from 1997 to 2006 [hazard ratio (HR) 1.06; P < 0.004]. Eastern Cooperative Oncology Group performance status (HR 1.48; P < 0.001), use of second-line treatment (HR 1.51; P < 0.001), and Union for International Cancer Control (UICC) stage (III versus IV) (HR 1.34, P = 0.002) had a significant impact on OS. By contrast, no influence of age and gender on OS was detectable. Comparing combination therapy with single-agent chemotherapy did not demonstrate a survival benefit, nor did regimens containing epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) such as afatinib or erlotinib, compared with chemotherapy-only arms. Patients with early-onset pancreatic cancer (age at study entry of ≤50 years, n = 102) had a similar OS compared with those >50 years (7.1 versus 7.0 months; HR 1.13; P = 0.273). The use of a platinum-containing regimen was not associated with better outcomes in patients with early-onset pancreatic cancer.

CONCLUSIONS

Within this selected group of patients treated within prospective clinical trials, survival has shown improvement over two decades. This effect is likely attributable to the availability of more effective combination therapies and treatment lines, rather than to any specific regimen, such as those containing EGFR-TKIs. In addition, concerning age and sex subgroups, the dataset did not provide evidence for distinct clinical behavior.

An update on the secretory functions of brown, white, and beige adipose tissue: Towards therapeutic applications

Adipose tissue, including white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue, is vital in modulating whole-body energy metabolism. While WAT primarily stores energy, BAT dissipates energy as heat for thermoregulation. Beige adipose tissue is a hybrid form of adipose tissue that shares characteristics with WAT and BAT. Dysregulation of adipose tissue metabolism is linked to various disorders, including obesity, type 2 diabetes, cardiovascular diseases, cancer, and infertility. Both brown and beige adipocytes secrete multiple molecules, such as batokines, packaged in extracellular vesicles or as soluble signaling molecules that play autocrine, paracrine, and endocrine roles. A greater understanding of the adipocyte secretome is essential for identifying novel molecular targets in treating metabolic disorders. Additionally, microRNAs show crucial roles in regulating adipose tissue differentiation and function, highlighting their potential as biomarkers for metabolic disorders. The browning of WAT has emerged as a promising therapeutic approach in treating obesity and associated metabolic disorders. Many browning agents have been identified, and nanotechnology-based drug delivery systems have been developed to enhance their efficacy. This review scrutinizes the characteristics of and differences between white, brown, and beige adipose tissues, the molecular mechanisms involved in the development of the adipocytes, the significant roles of batokines, and regulatory microRNAs active in different adipose tissues. Finally, the potential of WAT browning in treating obesity and atherosclerosis, the relationship of BAT with cancer and fertility disorders, and the crosstalk between adipose tissue with circadian system and circadian disorders are also investigated.

Targeting cancer-derived extracellular vesicles by combining CD147 inhibition with tissue factor pathway inhibitor for the management of urothelial cancer cells

BACKGROUND

Extracellular vesicles (EVs), including microvesicles, hold promise for the management of bladder urothelial carcinoma (BLCA), particularly because of their utility in identifying therapeutic targets and their diagnostic potential using easily accessible urine samples. Among the transmembrane glycoproteins highly enriched in cancer-derived EVs, tissue factor (TF) and CD147 have been implicated in promoting tumor progression. In this in vitro study, we explored a novel approach to impede cancer cell migration and metastasis by simultaneously targeting these molecules on urothelial cancer-derived EVs.

METHODS

Cell culture supernatants from invasive and non-invasive bladder cancer cell lines and urine samples from patients with BLCA were collected. Large, microvesicle-like EVs were isolated using sequential centrifugation and characterized by electron microscopy, nanoparticle tracking analysis, and flow cytometry. The impact of urinary or cell supernatant-derived EVs on cellular phenotypes was evaluated using cell-based assays following combined treatment with a specific CD147 inhibitor alone or in combination with a tissue factor pathway inhibitor (TFPI), an endogenous anticoagulant protein that can be released by low-molecular-weight heparins.

RESULTS

We observed that EVs obtained from the urine samples of patients with muscle-invasive BLCA and from the aggressive bladder cancer cell line J82 exhibited higher TF activity and CD147 expression levels than did their non-invasive counterparts. The shedding of GFP-tagged CD147 into isolated vesicles demonstrated that the vesicles originated from plasma cell membranes. EVs originating from invasive cancer cells were found to trigger migration, secretion of matrix metalloproteinases (MMPs), and invasion. The same induction of MMP activity was replicated using EVs obtained from urine samples of patients with invasive BLCA. EVs derived from cancer cell clones overexpressing TF and CD147 were produced in higher quantities and exhibited a higher invasive potential than those from control cancer cells. TFPI interfered with the effect when used in conjunction with the CD147 inhibitor, further suppressing homotypic EV-induced migration, MMP production, and invasion.

CONCLUSIONS

Our findings suggest that combining a CD147 inhibitor with low molecular weight heparins to induce TFPI release may be a promising therapeutic approach for urothelial cancer management. This combination can potentially suppress the tumor-promoting actions of cancer-derived microvesicle-like EVs, including collective matrix invasion.

Contributing and limiting factors to guideline-adherent therapy in senior and elderly breast cancer patients: a questionnaire-based cross-sectional study using clinical and cancer registry data in Germany

PURPOSE

Elderly cancer patients are less likely to be treated in accordance with evidence-based guideline recommendations. This study examines patient-related factors associated with deviations from guideline recommendations.

METHODS

Using medical documentation and cancer registry data, we investigated the treatment courses of female breast cancer patients aged 50 and older in Germany regarding compliance with German guidelines. Participants completed a questionnaire querying factors hypothesized to be associated with guideline adherence. We conducted univariate analyses to explore the data and select variables for multivariate logistic regression to estimate adjusted odds ratios.

RESULTS

Of 1150 participants, 206 (17.9%) were treated in deviation from guideline recommendations. Patients 70 years and older were more likely to be treated deviating from guideline recommendations than patients 50-69 years old (OR: 2.07; 95% CI: 1.52-2.80). Patients aged 50-69 years who reported that quality of life guided their treatment decision were more likely to be treated in deviation from guideline recommendations (AOR: 2.08; 95% CI: 1.11-3.92) than the elderly. In older patients, higher age was associated with an increased chance of receiving guideline-discordant care (AOR: 1.06; 95% CI: 1.01-1.11), as was depression diagnosed prior to cancer (AOR: 1.84; 95% CI: 1.00-3.40).

CONCLUSION

Reasons for deviations from guideline recommendations in breast cancer patients differ by age. In decision-making concerning elderly patients, particular attention should be paid to those with pre-existing depressive disorders. Adequately addressing their needs and concerns could prevent inappropriate deviations from guideline recommendations.

Physicians' perspectives on family caregivers' roles in elderly cancer patients' therapies: a qualitative, interview-based study

PURPOSE

Clinical communication and facilitating informed and sound medical decisions become challenging as patients age and suffer from age-associated impairments. Family caregivers are perceived as essential actors in addressing these challenges. Here, we explore physicians' perspectives on family caregivers' roles and their involvement in consultations and therapy decision-making situations of elderly cancer patients.

METHODS

We examined 38 semi-structured interviews with physicians from different specialities (oncologists, non-oncology specialists, and general practitioners) in Germany who treated elderly cancer patients. Data were analyzed using reflexive thematic analysis.

RESULTS

We identified five general and distinct perspectives on the involvement of family caregivers in the therapy process. Family caregivers are seen as (1) translators of medical information; (2) providers of support for the patient; (3) providers of information about the patient; (4) stakeholders with relevant points of view regarding the treatment decision; or (5) individuals who have a disruptive influence on the consultation. The interviewed physicians rarely involved family caregivers closely in consultations.

CONCLUSIONS

Although physicians frequently attribute supportive roles to family caregivers, they rarely include them in consultations. Previous studies have found that a triadic setting is often better suited to agreeing upon a patient-centered and needs-based treatment decision for older cancer patients. We infer that physicians too rarely recognize the potential importance of family caregivers. Educators should further integrate family caregiver involvement and its implications in general medical education and professional training.

The role of family confidants and caregivers in the care of older cancer patients: Extending the concept of "shared decision-making"

BACKGROUND AND AIMS

Family caregivers play an important role in assisting their family members with cancer, but their influence on the treatment decision-making process has not yet been adequately investigated. This exploratory study approached this topic via reconstructive methodology, focusing on assessing patient-caregiver relationships.

METHODS

We conducted semi-structured interviews with 37 mostly elderly cancer patients (median age: 74 years) about the context of their diagnosis, treatment decision, and family support. Additionally, we interviewed 34 caregivers of cancer patients. Of these, 25 were related to patients interviewed. We analyzed the interviews via a multi-step coding method informed by Grounded Theory methodology toward characterizing patient-caregiver relationships, the treatment decision-making process, and the caregivers' role therein.

RESULTS

In the majority of cases (86%), patients were being supported by caregivers. We categorized patient-caregiver relationships in regards to the caregivers' involvement in the therapy decision-making process. We found patient-caregiver interaction patterns that indicate the potential of caregivers to decidedly influence the therapy decision-making process. Yet, only in 38% of cases, a caregiver attended relevant patient-physician-consultations.

CONCLUSION

Depending on the nature of the patient-caregiver relationship, the traditional concept of shared decision-making, which assumes a dyadic relationship, needs to be extended toward a more dynamic concept in which caregivers should be involved more frequently. This could enable physicians to better understand a patient's reasons for or against a therapy proposal and ensure that the patient's wishes are communicated and considered. On the other hand, strong caregiver-involvement bears risks of over-stepping elderly patients' wishes, thus violating patient autonomy.

Ambrisentan, an endothelin receptor type A-selective antagonist, inhibits cancer cell migration, invasion, and metastasis

Several studies reported a central role of the endothelin type A receptor (ETAR) in tumor progression leading to the formation of metastasis. Here, we investigated the in vitro and in vivo anti-tumor effects of the FDA-approved ETAR antagonist, Ambrisentan, which is currently used to treat patients with pulmonary arterial hypertension. In vitro, Ambrisentan inhibited both spontaneous and induced migration/invasion capacity of different tumor cells (COLO-357 metastatic pancreatic adenocarcinoma, OvCar3 ovarian carcinoma, MDA-MB-231 breast adenocarcinoma, and HL-60 promyelocytic leukemia). Whole transcriptome analysis using RNAseq indicated Ambrisentan's inhibitory effects on the whole transcriptome of resting and PAR2-activated COLO-357 cells, which tended to normalize to an unstimulated profile. Finally, in a pre-clinical murine model of metastatic breast cancer, treatment with Ambrisentan was effective in decreasing metastasis into the lungs and liver. Importantly, this was associated with a significant enhancement in animal survival. Taken together, our work suggests a new therapeutic application for Ambrisentan in the treatment of cancer metastasis.

Tissue factor activity on microvesicles from cancer patients

PURPOSE

The expression of active tissue factor (TF) on the surface of microvesicles (MVs) is essential for the activation of the coagulation system and transduction of the signaling pathways in cancer cells. In its use as a biomarker for cancer-associated venous thromboembolism (VTE), TF has shown high expression variability. As a contribution to this discussion, we present a study investigating plasma samples from patients with various progressive tumors at high risk for VTE.

METHODS

Based on our previous study uncovering microvesicles (MVs), the larger ectosome-like extracellular vesicles (EV), as the major source of TF activity in EV preparations, we now determined TF activity on enriched MVs isolated from plasma of cancer patients and compared it with that on MVs from healthy individuals.

RESULTS

We found considerably higher amounts of MVs as well as higher levels of MV-bound TF activities in the plasma of cancer patients. We also show that preparations from plasma of cancer patients have the potency to induce ERK phosphorylation in a human tumor cell line through proteinase-activated receptor two (PAR2) activation.

CONCLUSION

We suggest that MVs instead of whole EV preparations, and TF activity rather than its antigenic quantification should be used in clinical studies for identifying patients with progressive tumors at high risk for VTE.

Extracellular Vesicles: Subcellular Organelles With the Potential to Spread Cancer Resistance

Although modern anticancer drugs have made great progress in disease treatment, the occurrence of drug resistance often leads to treatment failure. Understanding the molecular basis of resistance mechanisms is important to determine prognosis and develop strategies for circumvention. In this context, subcellular vesicles released by cancer cells have been identified to mediate cellular resistance by various mechanisms. Such extracellular vesicles (EVs) can be subdivided into exosomes and ectosomes based on their size, cargo, and mechanism of formation. The unveiling of EV-targeted treatment options depends on a sound knowledge on EV biology including biogenesis, release, targeting to recipient cells, and uptake. In this review, we focus on EVs as mediators of cancer drug resistance with a particular emphasis on the distinction of exosomes and ectosomes.

Prognostic relevance of topoisomerase II α and minichromosome maintenance protein 6 expression in colorectal cancer

BACKGROUND

Despite rising incidence rates of colorectal malignancies, only a few prognostic tools have been implemented in proven clinical routine. Cell division and proliferation play a significant role in malignancies. In terms of colorectal cancer, the impact of proliferation associated proteins is controversially debated. The aim of our study was to examine the expression of topoisomerase II α and minichromosome maintenance protein 6 and to correlate these findings with the clinical data.

METHODS

Tissue samples of 619 patients in total were stained using the antibodies Ki-S4 and Ki-MCM6 targeting topoisomerase II α as well as minichromosome maintenance protein 6. The median rate of proliferation was correlated with clinical and follow up data.

RESULTS

The expression rate of minichromosome maintenance protein 6 is significantly higher than the proportion of topoisomerase II α in tumour cells (p < 0.001). A high expression of both proteins coincides with a beneficial outcome for the patient, indicating a favourable prognostic marker (p < 0.001 and p = 0.008).

CONCLUSIONS

We have demonstrated that high expression rates of proliferative markers is linked to a beneficial patient outcome. According to the general opinion, a high expression rate correlates with a poor patient outcome. In this study, we were able to refute this assertion.

GPCR-specific autoantibody signatures are associated with physiological and pathological immune homeostasis

Autoantibodies have been associated with autoimmune diseases. However, studies have identified autoantibodies in healthy donors (HD) who do not develop autoimmune disorders. Here we provide evidence of a network of immunoglobulin G (IgG) autoantibodies targeting G protein-coupled receptors (GPCR) in HD compared to patients with systemic sclerosis, Alzheimer's disease, and ovarian cancer. Sex, age and pathological conditions affect autoantibody correlation and hierarchical clustering signatures, yet many of the correlations are shared across all groups, indicating alterations to homeostasis. Furthermore, we identify relationships between autoantibodies targeting structurally and functionally related molecules, such as vascular, neuronal or chemokine receptors. Finally, autoantibodies targeting the endothelin receptor type A (EDNRA) exhibit chemotactic activity, as demonstrated by neutrophil migration toward HD-IgG in an EDNRA-dependent manner and in the direction of IgG from EDNRA-immunized mice. Our data characterizing the in vivo signatures of anti-GPCR autoantibodies thus suggest that they are a physiological part of the immune system.

Heterogeneity of microvesicles from cancer cell lines under inflammatory stimulation with TNF-α

Microvesicles (MVs) represent a subgroup of extracellular vesicles (EVs) emerging from various cells by blebbing of their outer membrane. Therefore, they share features such as membrane composition and antigenicity with their parental cells. Released by many immune and tumor cells, MVs act as intercellular messengers, account for horizontal gene transfer and can activate the coagulation system. With the aim to investigate their relevance for tumor cell biology, we characterized MVs released by human tumor cell lines of various origins in the absence or presence of TNF-α. After stimulation, we used the combination of low and high-speed centrifugation to enrich MVs from cell culture supernatants. We analyzed the presentation of phosphatidylserine (PS) and tissue factor (TF) activity on the cell surface and investigated their potency to induce tumor cell migration. In all tumor cell lines, TNF-α stimulation enhanced the release of MVs. While the expression of PS was universally increased, an elevated activity of procoagulant TF could be detected on MVs from lung, pancreatic, and colon carcinoma, but not from breast and ovarian cancer cell lines. Functionally, TNF-α stimulation significantly increased the potency of MVs to induce tumor cell migration. In conclusion, inflammatory conditions promote the release of MVs with increased procoagulant activity from tumor cell lines in vitro. PS-containing and TF-expressing MVs may account for systemic activation of the coagulation system as seen in cancer patients and, since they induce tumor cell migration, they may serve as biomarkers for tumor progression.

The Role of PAR2 in TGF-β1-Induced ERK Activation and Cell Motility

Background: Recently, the expression of proteinase-activated receptor 2 (PAR2) has been shown to be essential for activin receptor-like kinase 5 (ALK5)/SMAD-mediated signaling and cell migration by transforming growth factor (TGF)-β1. However, it is not known whether activation of non-SMAD TGF-β signaling (e.g., RAS–RAF–MEK–extracellular signal-regulated kinase (ERK) signaling) is required for cell migration and whether it is also dependent on PAR2. Methods: RNA interference was used to deplete cells of PAR2, followed by xCELLigence technology to measure cell migration, phospho-immunoblotting to assess ERK1/2 activation, and co-immunoprecipitation to detect a PAR2–ALK5 physical interaction. Results: Inhibition of ERK signaling with the MEK inhibitor U0126 blunted the ability of TGF-β1 to induce migration in pancreatic cancer Panc1 cells. ERK activation in response to PAR2 agonistic peptide (PAR2–AP) was strong and rapid, while it was moderate and delayed in response to TGF-β1. Basal and TGF-β1-dependent ERK, but not SMAD activation, was blocked by U0126 in Panc1 and other cell types indicating that ERK activation is downstream or independent of SMAD signaling. Moreover, cellular depletion of PAR2 in HaCaT cells strongly inhibited TGF-β1-induced ERK activation, while the biased PAR2 agonist GB88 at 10 and 100 µM potentiated TGF-β1-dependent ERK activation and cell migration. Finally, we provide evidence for a physical interaction between PAR2 and ALK5. Our data show that both PAR2–AP- and TGF-β1-induced cell migration depend on ERK activation, that PAR2 expression is crucial for TGF-β1-induced ERK activation, and that the functional cooperation of PAR2 and TGF-β1 involves a physical interaction between PAR2 and ALK5.

Pathophysiological considerations to thrombophilia in the treatment of multiple myeloma with thalidomide and derivates

Lenalidomide, a derivate of thalidomide, has recently been approved in Europe for the treatment of patients with multiple myeloma. Although the substance has a better effect/side-effect profile, especially with regard to teratogenicity and neurotoxicity, the rate of therapy-induced thrombosis seems comparable to thalidomide. The observed thromboembolic events were accompanied with a high rate of deleterious pulmonary embolism. Interestingly, the substances alone are not thrombogenic but combination with anthracyclines, dexamethasone or erythropesis-stimulating factors increases the risk considerably. As up to one third of patients treated with such combinations are affected, antithrombotic co-medication is highly recommended. This review elucidates the complex interactions between an activated coagulation-system in myeloma patients and the molecular effects of these drugs. This perception is important to choose the proper prophylactic co-medication without increasing the risk of bleeding, especially in first-line treatment, patients with high paraprotein-levels, or thrombopenia, either therapy-induced or due to bone-marrow infiltration.

Activated coagulation factors in human malignant effusions and their contribution to cancer cell metastasis and therapy

We have shown that the thrombin G-protein coupled receptors (GPCR) designated as protease-activated receptors (PAR-1) are expressed in primary cancer cells isolated from peritoneal and pleural malignant effusions. Here, our main goal was to evaluate several coagulation and thrombin activation effectors and markers in a series of 136 malignant effusions from cancer patients with gastrointestinal, lung and mammary carcinomas. All these patients present a highly activated coagulation system in blood and their malignant effusions, as indicated by high levels of prothrombin F1.2 fragments and D-dimers. Notably, we detected in the effusions all the coagulation factors of the tissue factor pathway inducing thrombin activation, namely factorsVII, V, X and II, as well as high VEGF levels and IGF-II in mature and precursor forms. Fibrin clot formation also correlated with higher levels of free ionized calcium (iCa), suggesting that iCa and its binding protein albumin are regulatory factors for fibrinogenesis in effusions. Consequently, thrombin,VEGF and IGFII appear to converge in the promotion of survival and invasivity of the metastatic cancer cells from blood to the malignant effusions. Thus, we add new insights on the interconnections between blood coagulation disorders in cancer patients and thrombin activation in malignant effusions, including their functional interaction with PAR in metastatic cancer cells. Based on these data we propose to counteract the metastatic cascades by targeted invalidation of key effectors of the coagulation system. Therefore, potential therapeutic approaches include the application of thrombin protease inhibitors, VEGF-blocking antibodies, and drugs targeting the VEGF and thrombin signaling pathways, such as tyrosine kinase or GPCR inhibitors.

Proteinase-Activated Receptor 2 May Drive Cancer Progression by Facilitating TGF-β Signaling

The G protein-coupled receptor proteinase-activated receptor 2 (PAR2) has been implicated in various aspects of cellular physiology including inflammation, obesity and cancer. In cancer, it usually acts as a driver of cancer progression in various tumor types by promoting invasion and metastasis in response to activation by serine proteinases. Recently, we discovered another mode through which PAR2 may enhance tumorigenesis: crosstalk with transforming growth factor-β (TGF-β) signaling to promote TGF-β1-induced cell migration/invasion and invasion-associated gene expression in ductal pancreatic adenocarcinoma (PDAC) cells. In this chapter, we review what is known about the cellular TGF-β responses and signaling pathways affected by PAR2 expression, the signaling activities of PAR2 required for promoting TGF-β signaling, and the potential molecular mechanism(s) that underlie(s) the TGF-β signaling-promoting effect. Since PAR2 is activated through various serine proteinases and biased agonists, it may couple TGF-β signaling to a diverse range of other physiological processes that may or may not predispose cells to cancer development such as local inflammation, systemic coagulation and pathogen infection.

Proteinase-Activated Receptor 2 Is a Novel Regulator of TGF-β Signaling in Pancreatic Cancer

TGF-β has a dual role in tumorigenesis, acting as a tumor suppressor in normal cells and in the early stages of tumor development while promoting carcinogenesis and metastasis in advanced tumor stages. The final outcome of the TGF-β response is determined by cell-autonomous mechanisms and genetic alterations such as genomic instability and somatic mutations, but also by a plethora of external signals derived from the tumor microenvironment, such as cell-to-cell interactions, growth factors and extracellular matrix proteins and proteolytic enzymes. Serine proteinases mediate their cellular effects via activation of proteinase-activated receptors (PARs), a subclass of G protein-coupled receptors that are activated by proteolytic cleavage. We have recently identified PAR2 as a factor required for TGF-β1-dependent cell motility in ductal pancreatic adenocarcinoma (PDAC) cells. In this article, we review what is known on the TGF-β-PAR2 signaling crosstalk and its relevance for tumor growth and metastasis. Since PAR2 is activated through various serine proteinases, it may couple TGF-β signaling to a diverse range of other physiological processes, such as local inflammation, systemic coagulation or pathogen infection. Moreover, since PAR2 controls expression of the TGF-β type I receptor ALK5, PAR2 may also impact signaling by other TGF-β superfamily members that signal through ALK5, such as myostatin and GDF15/MIC-1. If so, PAR2 could represent a molecular linker between PDAC development and cancer-related cachexia.

Designing a broad-spectrum integrative approach for cancer prevention and treatment

Targeted therapies and the consequent adoption of "personalized" oncology have achieved notable successes in some cancers; however, significant problems remain with this approach. Many targeted therapies are highly toxic, costs are extremely high, and most patients experience relapse after a few disease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistant immortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are not reliant upon the same mechanisms as those which have been targeted). To address these limitations, an international task force of 180 scientists was assembled to explore the concept of a low-toxicity "broad-spectrum" therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspects of relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a wide range of high-priority targets (74 in total) that could be modified to improve patient outcomes. For these targets, corresponding low-toxicity therapeutic approaches were then suggested, many of which were phytochemicals. Proposed actions on each target and all of the approaches were further reviewed for known effects on other hallmark areas and the tumor microenvironment. Potential contrary or procarcinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixed evidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of the relationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. This novel approach has potential to be relatively inexpensive, it should help us address stages and types of cancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for future research is offered.

Extracellular vesicles from malignant effusions induce tumor cell migration: inhibitory effect of LMWH tinzaparin

Elevated levels of extracellular vesicles (EVs) have been correlated with inflammatory diseases as well as progressive and metastatic cancer. By presenting tissue factor (TF) on their membrane surface, cellular microparticles (MPs) activate both the coagulation system and cell-signaling pathways such as the PAR/ERK pathway. We have shown before that malignant effusions are a rich source of tumor cell-derived EVs. Here, we used EVs from malignant effusions from three different patients after serial low-speed centrifugation steps as recommended by the ISTH (lsEV). Significant migration of human pancreatic carcinoma cells could be induced by lsEVs and was effectively inhibited by pre-incubation with tinzaparin, a low-molecular-weight heparin. Tinzaparin induced tissue factor pathway inhibitor (TFPI) release from tumor cells, and recombinant TFPI inhibited EV-induced tumor cell migration. EVs also induced ERK phosphorylation, whereas inhibitors of PAR2 and ERK suppressed EV-induced tumor cell migration. LsEVs have been characterized by high-resolution flow cytometry and, after elimination of smaller vesicles including exosomes, by further high-speed centrifugation (hsEV). The remaining population consisting primarily of MPs is indeed the main migration-inducing population with tenase activity. Compared to other LMWHs, tinzaparin is suggested to have high potency to induce TFPI release from epithelial cells. The migration-inhibitory effect of TFPI and the interruption of tumor cell migration by inhibitors of PAR2 and ERK suggest that lsEVs induce tumor cell migration by activating the PAR2 signaling pathway. Tinzaparin might inhibit this process at least partly by inducing the release of TFPI from tumor cells, which blocks PAR-activating TF complexes. The clinical relevance of the results is discussed.

PO-18 - Fibronectin EDA/EDB is expressed in adherent SCLC NCI-H69 cells and in pleural effusions of lung cancer patients: possible implication for drug resistance

INTRODUCTION

Small cell lung cancer (SCLC) is an extremely aggressive tumour which metastasizes early. Even if chemotherapy can achieve an initial regression, relapses due to chemo-resistance are almost inevitable. Sethi et al (Nat Med. 1999;5:662-668) reported that matrix proteins are essentially involved in the development of drug resistance. SCLC cells in suspension culture secrete negligible amounts of matrix proteins

AIM

For a more detailed study of the SCLC ability to produce matrix proteins we applied a recently introduced cell culture model of adherence selected SCLC (Salge et al. J Cancer Res Clin Oncol. 2001;127(2):139-411) and analysed pleural effusions form lung cancer patients.

MATERIALS AND METHODS

Adherent cells were selected from the SCLC cell line NCI-H69 after exposure to cellular stress. Pleural effusion were obtained from lung cancer patients (SCLC and NSCLC) and from pleural effusions (PE) with congestive heart failure Protein expression was analysed by western blotting (WB) and flow cytometry using specific antibodies against the fibronectin extra domain A (FnEDA) and B (FnEDB) (Sirius, Italy), and for integrins alpha 1-5 and beta 1-3. Drug resistance was assessed with the metabolic stain MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromid).

RESULTS

SCLC suspension cells expressed negligible amounts of fibronectin. In contrast, adherent H69 cells, which showed a significantly reduced chemo-sensitivity against carboplatin and doxorubicin, strongly expressed FnEDA and to a lesser extent FnEDB. Furthermore, in adherent cells expression of various integrins was up-regulated, in particular integrins alpha5/beta3, representing potential binding sites for FnEDA/FnEDB. Analysis of pleural effusions clearly showed the presence of FnEDA/ FnEDB in those of lung cancer patients, whereas in benign pleural effusion almost no FnEDA/ FnEDB was found.

CONCLUSIONS

Our data reveal the presence of Fn, and its splice variants FnEDA/EDB in particular, in adherent SCLC cells as well as in malignant PE. We assume that the splice variants FnEDA/ FnEDB are linked to cancer progression and chemo-resistance in this tumour type.

Dasatinib blocks transcriptional and promigratory responses to transforming growth factor-beta in pancreatic adenocarcinoma cells through inhibition of Smad signalling: implications for in vivo mode of action

Background

We have previously shown in pancreatic ductal adenocarcinoma (PDAC) cells that the SRC inhibitors PP2 and PP1 effectively inhibited TGF-β1-mediated cellular responses by blocking the kinase function of the TGF-β type I receptor ALK5 rather than SRC. Here, we investigated the ability of the clinically utilised SRC/ABL inhibitor dasatinib to mimic the PP2/PP1 effect.

Methods

The effect of dasatinib on TGF-β1-dependent Smad2/3 phosphorylation, general transcriptional activity, gene expression, cell motility, and the generation of tumour stem cells was measured in Panc-1 and Colo-357 cells using immunoblotting, reporter gene assays, RT-PCR, impedance-based real-time measurement of cell migration, and colony formation assays, respectively.

Results

In both PDAC cell lines, dasatinib effectively blocked TGF-β1-induced Smad phosphorylation, activity of 3TPlux and pCAGA₍₁₂₎-luc reporter genes, cell migration, and expression of individual TGF-β1 target genes associated with epithelial-mesenchymal transition and invasion. Moreover, dasatinib strongly interfered with the TGF-β1-induced generation of tumour stem cells as demonstrated by gene expression analysis and single cell colony formation. Dasatinib also inhibited the high constitutive migratory activity conferred on Panc-1 cells by ectopic expression of kinase-active ALK5.

Conclusions

Our data suggest that the clinical efficiency of dasatinib may in part be due to cross-inhibition of tumour-promoting TGF-β signalling. Dasatinib may be useful as a dual TGF-β/SRC inhibitor in experimental and clinical therapeutics to prevent metastatic spread in late-stage PDAC and other tumours.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0468-0) contains supplementary material, which is available to authorized users.

Obesity and cancer

The incidence of obesity in the Western world has increased dramatically during the recent decades. Epidemiological data suggest that obesity is associated with an increased risk of several but not all types of cancers, with clear sex-specific differences. The underlying mechanisms are still a matter of debate. In this review, we discuss the potential factors linking obesity to cancer, with a focus on hormone-dependent cancer types. Current experimental evidence suggests that insulin resistance and a chronic, subclinical inflammation in the visceral fat are the major metabolic events, causing alterations in the levels of insulin, glucose, free fatty acids, insulin-like growth factor-1 and -2, adipose tissue-derived proinflammatory factors (tumor necrosis factor-α and interleukin-1, -6, -12, and -23), and other bioactive molecules such as adipokines (adiponectin and leptin), vascular endothelial growth factor, sex hormones, gut microbiota, and secondary bile acids. All these factors may act directly or indirectly on the tumor microenvironment to drive tumor progression via the stimulation of cell survival/antiapoptosis, cell proliferation, angiogenesis, and invasion/metastasis of cancer cells. Therapeutic strategies (including bariatric surgery) that target dysfunctional or inflamed fat have been shown to benefit patients, whereas other cell- or hormone-directed interventions (such as the conversion of visceral fat macrophages to an anti-inflammatory M2 phenotype or the pharmacological modulation of serum adipokine levels) are still theoretical and need to be clinically evaluated for their ability to successfully treat or prevent obesity-related cancers.

Ionizing radiation induces a motile phenotype in human carcinoma cells in vitro through hyperactivation of the TGF-beta signaling pathway

Radiotherapy, a major treatment modality against cancer, can lead to secondary malignancies but it is uncertain as to whether tumor cells that survive ionizing radiation (IR) treatment undergo epithelial-mesenchymal transition (EMT) and eventually become invasive or metastatic. Here, we have tested the hypothesis that the application of IR (10 MeV photon beams, 2-20 Gy) to lung and pancreatic carcinoma cells induces a migratory/invasive phenotype in these cells by hyperactivation of TGF-β and/or activin signaling. In accordance with this assumption, IR induced gene expression patterns and migratory responses consistent with an EMT phenotype. Moreover, in A549 cells, IR triggered the synthesis and secretion of both TGF-β1 and activin A as well as activation of intracellular TGF-β/activin signaling as evidenced by Smad phosphorylation and transcriptional activation of a TGF-β-responsive reporter gene. These responses were sensitive to SB431542, an inhibitor of type I receptors for TGF-β and activin. Likewise, specific antibody-mediated neutralization of soluble TGF-β, or dominant-negative inhibition of the TGF-β receptors, but not the activin type I receptor, alleviated IR-induced cell migration. Moreover, the TGF-β-specific approaches also blocked IR-dependent TGF-β1 secretion, Smad phosphorylation, and reporter gene activity, collectively indicating that autocrine production of TGF-β(s) and subsequent activation of TGF-β rather than activin signaling drives these changes. IR strongly sensitized cells to further increase their migration in response to recombinant TGF-β1 and this was accompanied by upregulation of TGF-β receptor expression. Our data raise the possibility that hyperactivation of TGF-β signaling during radiotherapy contributes to EMT-associated changes like metastasis, cancer stem cell formation and chemoresistance of tumor cells.

Pluripotency gene expression and growth control in cultures of peripheral blood monocytes during their conversion into programmable cells of monocytic origin (PCMO): evidence for a regulatory role of autocrine activin and TGF-β

Previous studies have shown that peripheral blood monocytes can be converted in vitro to a stem cell-like cell termed PCMO as evidenced by the re-expression of pluripotency-associated genes, transient proliferation, and the ability to adopt the phenotype of hepatocytes and insulin-producing cells upon tissue-specific differentiation. However, the regulatory interactions between cultured cells governing pluripotency and mitotic activity have remained elusive. Here we asked whether activin(s) and TGF-β(s), are involved in PCMO generation. De novo proliferation of PCMO was higher under adherent vs. suspended culture conditions as revealed by the appearance of a subset of Ki67-positive monocytes and correlated with down-regulation of p21WAF1 beyond day 2 of culture. Realtime-PCR analysis showed that PCMO express ActRIIA, ALK4, TβRII, ALK5 as well as TGF-β1 and the βA subunit of activin. Interestingly, expression of ActRIIA and ALK4, and activin A levels in the culture supernatants increased until day 4 of culture, while levels of total and active TGF-β1 strongly declined. PCMO responded to both growth factors in an autocrine fashion with intracellular signaling as evidenced by a rise in the levels of phospho-Smad2 and a drop in those of phospho-Smad3. Stimulation of PCMO with recombinant activins (A, B, AB) and TGF-β1 induced phosphorylation of Smad2 but not Smad3. Inhibition of autocrine activin signaling by either SB431542 or follistatin reduced both Smad2 activation and Oct4A/Nanog upregulation. Inhibition of autocrine TGF-β signaling by either SB431542 or anti-TGF-β antibody reduced Smad3 activation and strongly increased the number of Ki67-positive cells. Furthermore, anti-TGF-β antibody moderately enhanced Oct4A/Nanog expression. Our data show that during PCMO generation pluripotency marker expression is controlled positively by activin/Smad2 and negatively by TGF-β/Smad3 signaling, while relief from growth inhibition is primarily the result of reduced TGF-β/Smad3, and to a lesser extent, activin/Smad2 signaling.

[Obesity and cancer]

The incidence of obesity in the western world has increased dramatically during recent decades. Epidemiological data suggest that obesity is associated with an increased risk of several but not all types of cancers, with clear sex-specific differences. The underlying mechanisms are still a matter of debate. This review focuses on the potential factors linking obesity to cancer. Current experimental evidence suggests that insulin resistance and a chronic, subclinical inflammation in the visceral fat are the major metabolic events causing alterations in the levels of insulin, glucose, free fatty acids, insulin-like growth factor 1 (IGF-1) and 2, adipose tissue-derived proinflammatory cytokines and other bioactive molecules, such as adipokines (e.g. leptin and adiponectin), vascular endothelial growth factor (VEGF), sex hormones, gut microbiota and secondary bile acids. All these factors may act directly or indirectly on the tumor microenvironment to drive tumor progression via stimulation of cell survival/antiapoptosis, cell proliferation, angiogenesis and invasion/metastasis of the cancer cells. Therapeutic strategies that target dysfunctional or inflamed fat and have been shown to benefit patients include bariatric surgery, while other cell or hormone-directed interventions, such as conversion of visceral fat macrophages to an anti-inflammatory M2 phenotype or the pharmacological modulation of serum adipokine levels are still theoretical and need to be clinically evaluated for their ability to successfully treat or prevent obesity-related cancers.

Using annexin V-coated magnetic beads to capture active tissue factor-bearing microparticles from body fluids

Microparticles, found in all body fluids including peripheral blood, are important elements that regulate cellular interactions under both physiological and pathological conditions. They play an important role in blood clot formation and increased cell aggregation. However, little is known about the components of the microparticles and their mechanism of action. A method to quantify and assess the underlying mechanism of action of microparticles in pathologies is therefore desirable. We present a specific method to isolate cell-derived microparticles from malignant effusions using annexin V-coated magnetic microbeads. The microparticles can be detected by flow cytometry. Our results show that the microparticles can be isolated with >80% specificity when bound to annexin V-coated magnetic beads, which was originally developed for the detection of apoptotic cells. We also show that the isolated microparticles were still functionally active and can be used for further analysis. Thus, our method enables isolation as well as structural and functional characterisation of the microparticles which are produced in numerous patho-physiological situations. This should help gain a deeper insight into various disease situations, which in turn should pave the way for the development of novel drugs and specific therapy strategies.

Proteinase-activated receptors (PARs) - focus on receptor-receptor-interactions and their physiological and pathophysiological impact

Proteinase-activated receptors (PARs) are a subfamily of G protein-coupled receptors (GPCRs) with four members, PAR₁, PAR₂, PAR₃ and PAR₄, playing critical functions in hemostasis, thrombosis, embryonic development, wound healing, inflammation and cancer progression. PARs are characterized by a unique activation mechanism involving receptor cleavage by different proteinases at specific sites within the extracellular amino-terminus and the exposure of amino-terminal “tethered ligand“ domains that bind to and activate the cleaved receptors. After activation, the PAR family members are able to stimulate complex intracellular signalling networks via classical G protein-mediated pathways and beta-arrestin signalling. In addition, different receptor crosstalk mechanisms critically contribute to a high diversity of PAR signal transduction and receptor-trafficking processes that result in multiple physiological effects.

In this review, we summarize current information about PAR-initiated physical and functional receptor interactions and their physiological and pathological roles. We focus especially on PAR homo- and heterodimerization, transactivation of receptor tyrosine kinases (RTKs) and receptor serine/threonine kinases (RSTKs), communication with other GPCRs, toll-like receptors and NOD-like receptors, ion channel receptors, and on PAR association with cargo receptors. In addition, we discuss the suitability of these receptor interaction mechanisms as targets for modulating PAR signalling in disease.

Characterization of spontaneous and TGF-β-induced cell motility of primary human normal and neoplastic mammary cells in vitro using novel real-time technology

The clinical complications derived from metastatic disease are responsible for the majority of all breast cancer related deaths. Since cell migration and invasion are a prerequisite for metastasis their assessment in patient cancer cells in vitro may have prognostic value for the tumor's metastatic capacity. We employed real-time cell analysis (RTCA) on the xCELLigence DP system to determine in vitro motility of patient-derived primary human breast cancer epithelial cells (HBCEC). Initially, the RTCA assay was validated using established human breast cancer cell lines with either an invasive (MDA-MB-231, MDA-MB-435s) or a non-invasive phenotype (MCF-7, MDA-MB-468), and primary NSCLC cells (Tu459). Previous standard assays of cell migration/invasion revealed that only MDA-MB-231, −435s, and Tu459 cells exhibited spontaneous and TGF-β1-stimulated migration and invasion through a Matrigel barrier. In the present study, the TGF-β1-stimulated activities could be blocked by SB431542, a potent kinase inhibitor of the TGF-β type I receptor ALK5. Application of the RTCA assay to patient-derived tumor cells showed that 4/4 primary HBCEC and primary NSCLC cells, but not normal human mammary epithelial cells (HMEC), displayed high spontaneous migratory and invasive activity which correlated with higher MMP-2 expression and uPA protein levels in HBCEC compared to HMEC. Upon treatment with TGF-β1, HBCEC exhibited morphologic and gene regulatory alterations indicative of epithelial-to-mesenchymal transition. However, exclusively the invasive but not the migratory activity of HBCEC was further enhanced by TGF-β1. This indicates the requirement for molecular, e.g. integrin interactions with Matrigel components in HBCEC in order to become responsive to pro-invasive TGF-β effects. Together, these results show for the first time that tumorigenic HBCEC but not normal HMEC possess a strong basal migratory as well as a basal and TGF-β1-inducible invasive potential. These findings qualify the RTCA assay as an in vitro migration/invasion testing system for patient-specific primary breast cancer cells.

Differential roles of Smad2 and Smad3 in the regulation of TGF-β1-mediated growth inhibition and cell migration in pancreatic ductal adenocarcinoma cells: control by Rac1

Background

Progression of pancreatic ductal adenocarcinoma (PDAC) is largely the result of genetic and/or epigenetic alterations in the transforming growth factor-beta (TGF-β)/Smad signalling pathway, eventually resulting in loss of TGF-β-mediated growth arrest and an increase in cellular migration, invasion, and metastasis. These cellular responses to TGF-β are mediated solely or partially through the canonical Smad signalling pathway which commences with activation of receptor-regulated Smads (R-Smads) Smad2 and Smad3 by the TGF-β type I receptor. However, little is known on the relative contribution of each R-Smad, the possible existence of functional antagonism, or the crosstalk with other signalling pathways in the control of TGF-β1-induced growth inhibition and cell migration. Using genetic and pharmacologic approaches we have inhibited in PDAC cells endogenous Smad2 and Smad3, as well as a potential regulator, the small GTPase Rac1, and have analysed the consequences for TGF-β1-mediated growth inhibition and cell migration (chemokinesis).

Results

SiRNA-mediated silencing of Smad3 in the TGF-β responsive PDAC cell line PANC-1 reduced TGF-β1-induced growth inhibition but increased the migratory response, while silencing of Smad2 enhanced growth inhibition but decreased chemokinesis. Interestingly, siRNA-mediated silencing of the small GTPase Rac1, or ectopic expression of a dominant-negative Rac1 mutant largely mimicked the effect of Smad2 silencing on both TGF-β1-induced growth inhibition, via upregulation of the cdk inhibitor p21^WAF1, and cell migration. Inhibition of Rac1 activation reduced both TGF-β1-induction of a Smad2-specific transcriptional reporter and Smad2 C-terminal phosphorylation in PDAC cells while Smad3-specific transcriptional activity and Smad3 C-terminal phosphorylation appeared increased. Disruption of autocrine TGF-β signalling in PANC-1 cells rendered cells less susceptible to the growth-suppressive effect of Rac1 inhibition, suggesting that the decrease in "basal" proliferation upon Rac1 inhibition was caused by potentiation of autocrine TGF-β growth inhibition.

Conclusions

In malignant cells with a functional TGF-β signalling pathway Rac1 antagonizes the TGF-β1 growth inhibitory response and enhances cell migration by antagonistically regulating Smad2 and Smad3 activation. This study reveals that Rac1 is prooncogenic in that it can alter TGF-β signalling at the R-Smad level from a tumour-suppressive towards a tumour-promoting outcome. Hence, Rac1 might represent a viable target for therapeutic intervention to inhibit PDAC progression.

Addition of darbepoetin alfa to dose-dense chemotherapy: results from a randomized phase II trial in small-cell lung cancer patients receiving carboplatin plus etoposide

Darbepoetin alfa, an erythropoiesis-stimulating agent (ESA), is used in cancer patients as a supportive care for anemia. For small-cell lung cancer (SCLC), several studies have shown that the administration of ESAs does not affect survival but decreases the need for blood transfusions and improves the quality of life (QOL) of patients receiving chemotherapy. The present randomized phase II study assessed the feasibility, efficacy, and safety of the administration of darbepoetin alfa to patients with SCLC receiving dose-dense (every 2 weeks) standard chemotherapy consisting of carboplatin plus etoposide, pegfilgrastim prophylactically. Seventy-four chemotherapy-naive patients with limited or extensive SCLC received combination chemotherapy for 6 cycles, and half of the patients additionally received darbepoetin to achieve a target hemoglobin concentration of 12-13 g/dL. The primary study outcome, progression-free survival, showed no difference between the 2 arms of the study. Among the secondary endpoints, objective response was similar in the presence and absence of darbepoetin (best response rates = 75.0% vs. 77.8%). Likewise, 1-year survival rates were not different between the 2 treatment arms (40.1% vs. 45.9%). There were no significant differences in grade 3/4 toxicities. As expected, the need for blood transfusions differed significantly: 19.4% of patients in the darbepoetin arm received transfusions versus 38.9% in the control arm. Analysis of European Organization for Research and Treatment of Cancer quality of life questionnaire (EORTC QLQ-C30) scales at different time points showed that the darbepoetin group's QOL was significantly better for certain readouts and never significantly worse than that of the control group. Thus, the combination of darbepoetin alfa with dose-dense carboplatin plus etoposide was feasible and well tolerated. Addition of darbepoetin alfa to chemotherapy lowered the need for blood transfusions and did not affect measures of survival and objective response.

Differential roles of Src in transforming growth factor-ß regulation of growth arrest, epithelial-to-mesenchymal transition and cell migration in pancreatic ductal adenocarcinoma cells

Both transforming growth factor (TGF)-ß and the non-receptor tyrosine kinase Src play major roles during tumorigenesis by regulating cell growth, epithelial-to-mesenchymal transition (EMT), migration/invasion and metastasis, but little is known about the signaling crosstalk between them. To interfere with Src function in vitro and in vivo many studies have employed the pharmacologic Src inhibitors PP2 and PP1. Both agents have recently been shown to be powerful inhibitors of TGF-ß receptor type I/ALK5 and type II. As this situation prohibited any definite conclusions with respect to the relative contribution of TGF-ß vs. Src signaling, we decided to reappraise a potential role of Src in TGF-ß1-mediated cellular responses using RNA and dominant-negative (dn) interference to block Src expression and function, respectively. In TGF-ß-responsive pancreatic ductal adenocarcinoma (PDAC) cells, we show that Src is activated by TGF-ß1 and that its specific inhibition strongly attenuated basal proliferation and enhanced TGF-ß1-mediated growth arrest. However, Src inhibition was unable to impair TGF-ß1-controlled EMT as evidenced by cell morphology and regulation of the epithelial marker E-cadherin. Despite its dispensibility for TGF-ß-induced EMT, specific inhibition of Src dramatically reduced basal and TGF-ß1-induced cell migration in Panc-1 cells as measured with a novel real-time migration assay (xCELLigence DP system). Biochemically, dnSrc inhibition failed to block TGF-ß1/ALK5-induced activation of Smad2 and Smad3, but partially inhibited transcriptional activation of TGF-ß/Smad-responsive reporter genes, and effectively blocked basal and TGF-ß1-induced activation of p38 MAPK. Together, the data provide evidence for a role of Src in the regulation of basal proliferation as well as in basal and TGF-ß1-mediated cell motility but not EMT in TGF-ß-responsive pancreatic (tumor) cells.

Temperature corrected transepithelial electrical resistance (TEER) measurement to quantify rapid changes in paracellular permeability

Determining the transepithelial electrical resistance (TEER) is a widely used method to functionally analyze tight junction dynamics in cell culture models of physiological barriers. Changes in temperature are known to have strong effects on TEER and can pose problems during the process of TEER measurements in cell culture vessels, complicating comparisons of TEER data across different experiments and studies. Here, we set out to devise a strategy to obtain temperature-independent TEER values based on the physical correlation between parameters such as TEER, temperature, medium viscosity and pore size of the cell culture inserts. By measuring the impact of temperature and different electrode types on TEER measurements on Caco-2 and HPDE (normal human pancreatic ductal epithelium) monolayers, we were able to derive a mathematical method that is suitable for the correction of TEER values for temperature changes. Applying this method to raw TEER values yields temperature-corrected TEER (tcTEER) values. Validity of tcTEER was demonstrated by showing a direct correlation with permeability of monolayers as determined by flux of RITC dextran. Taken together, the mathematical solution presented here allows for a simple and accurate determination of paracellular permeability independent of temperature variation during the process of TEER recording.

Toll-like receptors 3 and 7 agonists enhance tumor cell lysis by human gammadelta T cells

Toll-like receptor (TLR) agonists are considered adjuvants in clinical trials of cancer immunotherapy. Here, we investigated the modulation of gammadelta T cell-mediated tumor cell lysis by TLR ligands. gammadelta T-cell cytotoxicity and granzyme A/B production were enhanced after pretreatment of tumor cells with TLR3 [poly(I:C)] or TLR7 ligand (imiquimod). We examined TLR3- and TLR7-expressing pancreatic adenocarcinomas, squamous cell carcinomas of head and neck and lung carcinomas. Poly(I:C) treatment of pancreatic adenocarcinomas followed by coculture with gammadelta T cells resulted in an upregulation of CD54 on the tumor cells. The interaction of CD54 and the corresponding ligand CD11a/CD18 expressed on gammadelta T cells is responsible for triggering effector function in gammadelta T cells. Moreover, treatment with imiquimod downregulated MHC class I molecules on tumor cells possibly resulting in a reduced binding affinity for inhibitory receptor NKG2A expressed on gammadelta T cells. These results indicate that TLR3 or TLR7 ligand stimulation of tumor cells enhances the cytotoxic activity of expanded gammadelta T cells of cancer patients in vitro.

Elevated bladder cancer risk due to colorants--a statewide case-control study in North Rhine-Westphalia, Germany

Occupational exposure to aromatic amines is a known bladder cancer risk factor, whereas the impact of exposure to azo dyes, which may release aromatic amines in humans, is at present controversial. Therefore, the impact of occupational exposures to colorants was investigated in 156 bladder cancer cases and 336 controls in the state of North Rhine-Westphalia. All bladder cancer cases and controls (diagnosed with prostate cancer) requested after-care treatment. The subjects were investigated using a questionnaire for all occupations ever performed for more than 6 mo and for exposures to several possible occupational and nonoccupational bladder carcinogens. The relative bladder cancer risk was adjusted for age and smoking. The adjusted odds ratio (OR) for bladder cancer was elevated in 7 painters (OR 1.98, 95% CI 0.64-6.11), 4 hairdressers (OR 4.9, 95% CI 0.85-28.39), and 16 cases who reported a wood processing occupation (OR 1.19, 95% CI 0.58-2.41). Ten of these 16 cases reported chronic exposure to colorants (OR 1.84, 95% CI 0.68-4.95). The results of this epidemiological study confirm the hypothesis that individuals exposed to colorants show an elevated bladder cancer risk.

Repair of idarubicin-induced DNA damage: A cause of resistance?

Idarubicin, a widely used anticancer drug inhibits topoisomerase (topo) IIalpha and induces DNA double strand breaks. The finding that idarubicin-induced DNA damage is repaired before cell death is initiated encouraged us to examine the role of DNA repair for the cytotoxicity of idarubicin in human promyelocytic HL60 leukaemia cells. We found that DNA double strand breaks induced by a 90 min transient exposure to 0.5 microgml(-1) idarubicin were rapidly repaired throughout the whole population, while topo IIalpha itself was degraded. In spite of DNA repair, the vast majority of cells died within 40 h. Using differential staining of the chromatids and microscopic evaluation of DNA break points, we found evidence for a high number of false ligations of loose DNA strands arising from the inhibition of topo IIalpha action by idarubicin. If mainly actively transcribed genes are affected, this results in a disruption of vital genetic information, of regulatory sequences and, ultimately, in induction of the cell death pathway. Our results confirm the hypothesis that misrepair of DNA damage is a decisive event in idarubicin-induced cell death. They are discussed in the context of topo IIalpha-function and the currently known mechanisms of DNA double strand break repair.

Lysis of a broad range of epithelial tumour cells by human gamma delta T cells: involvement of NKG2D ligands and T-cell receptor- versus NKG2D-dependent recognition

Human gammadelta T cells expressing a V gamma 9V delta 2 T-cell receptor (TCR) kill various tumour cells including autologous tumours. In addition to TCR-dependent recognition, activation of NKG2D-positive gammadelta T cells by tumour cell-expressed NKG2D ligands can also trigger cytotoxic effector function. In this study, we investigated the involvement of TCR versus NKG2D in tumour cell recognition as a prerequisite to identify tumour types suitable for gammadelta T-cell-based immunotherapy. We have characterized epithelial tumour cells of different origin with respect to cell surface expression of the known NKG2D ligands MHC class I-chain-related antigens (MIC) A/B and UL16-binding proteins (ULBP), and susceptibility to gammadelta T-cell killing. Most tumour cells expressed comparable levels of MICA and MICB as well as ULBP with the exception of ULBP-1 which was absent or only weakly expressed. Most epithelial tumours were susceptible to allogeneic gammadelta T-cell lysis and in the case of an established ovarian carcinoma to autologous gammadelta T-cell killing. Lysis of resistant cells was enhanced by pre-treatment of tumour cells with aminobisphosphonates or pre-activation of gammadelta T cells with phosphoantigens. A potential involvement of TCR and/or NKG2D was investigated by antibody blockade. These experiments revealed three patterns of inhibition, i.e. preferential inhibition by anti-TCR antibody, preferential inhibition by anti-NKG2D antibody, or additive blockade by anti-TCR plus anti-NKG2D antibodies. Our results indicate for the first time that the NKG2D pathway is involved in the lysis of different melanomas, pancreatic adenocarcinomas, squamous cell carcinomas of the head and neck, and lung carcinoma.

[Coagulation and formation of malignant effusions]

Malignant effusions are a frequent problem for cancer patients. Due to the high resistance of tumor cells within these effusions, no effective treatment has been defined yet. Most patients exhibit additional phenomena related to hyper-coagulability such as elevated levels for d-dimers and prothrombin fragments f1.2; half of them suffer from manifest thrombosis or complications. We followed the hypothesis that the activated coagulation system contributes to the resistance of tumor cells and analyzed the effusions from cancer patients. The majority of isolated tumor cells aberrantly expressed PAR-1 thrombin receptors. In vitro pre-incubation of PAR-1 expressing human leukemia cells with thrombin resulted in a dose-dependent resistance to idarubicin. Within the effusions, we did not only find high concentrations of VEGF and tissue factor, but also all coagulation factors of the tissue factor pathway. Very high levels of prothrombin fragments f1.2 indicate constant thrombin generation. Upon the basis of these findings, we developed a multistep model elucidating the pathophysiological generation of malignant effusions, which might serve as a basis for further examinations.

Activated coagulation factors in human malignant effusions and their contribution to cancer cell metastasis and therapy

We have shown that the thrombin G-protein coupled receptors (GPCR) designated as protease-activated receptors (PAR-1) are expressed in primary cancer cells isolated from peritoneal and pleural malignant effusions. Here, our main goal was to evaluate several coagulation and thrombin activation effectors and markers in a series of 136 malignant effusions from cancer patients with gastrointestinal, lung and mammary carcinomas. All these patients present a highly activated coagulation system in blood and their malignant effusions, as indicated by high levels of prothrombin F1.2 fragments and D-dimers. Notably, we detected in the effusions all the coagulation factors of the tissue factor pathway inducing thrombin activation, namely factors VII, V, X and II, as well as high VEGF levels and IGF-II in mature and precursor forms. Fibrin clot formation also correlated with higher levels of free ionized calcium (iCa), suggesting that iCa and its binding protein albumin are regulatory factors for fibrinogenesis in effusions. Consequently, thrombin, VEGF and IGFII appear to converge in the promotion of survival and invasivity of the metastatic cancer cells from blood to the malignant effusions. Thus, we add new insights on the interconnections between blood coagulation disorders in cancer patients and thrombin activation in malignant effusions, including their functional interaction with PAR in metastatic cancer cells. Based on these data we propose to counteract the metastatic cascades by targeted invalidation of key effectors of the coagulation system. Therefore, potential therapeutic approaches include the application of thrombin protease inhibitors, VEGF-blocking antibodies, and drugs targeting the VEGF and thrombin signaling pathways, such as tyrosine kinase or GPCR inhibitors.

Die Rolle des Gerinnungssystems bei der Entstehung maligner Ergüsse

Maligne Ergüsse sind ein typisches Problem von Patienten mit fortgeschrittenen Tumorerkrankungen, eine Behandlung wird durch eine hohe Zytostatikaresistenz der Tumorzellen erschwert. Viele Patienten leiden an einer gleichzeitig bestehenden Hyperkoagulabilität mit hohen Spiegeln für D-Dimer und Prothrombin Fragment F1.2, etwa die Hälfte an Thrombosen und deren Folgeerkrankungen. Wir haben die Hypothese verfolgt, dass ein aktiviertes Gerinnungssystem eine der Ursachen für die hohe Zytostatikaresistenz der Tumorzellen darstellt und haben die Ergüsse von Tumorpatienten weiter untersucht. Die isolierten Tumorzellen zeigten zum großen Teil ein aberrante Expression des Thrombinrezeptors PAR-1. Durch Vorinkubation mit Thrombin konnte dosisabhängig eine komplette Resistenz gegen das Zytostatikum Idarubicin (IC50) erreicht werden. In den Ergüssen fanden wir, neben sehr hohen Konzentrationen von VEGF und Tissue-Faktor, sämtliche Faktoren des Tissue-Faktor-Pathways. Eine starke Thrombinaktivierung konnte durch hohe Spiegel von Prothrombin Fragment F1.2 nachgewiesen werden. Wir präsentieren ein Modell der Entstehung maligner Ergüsse, das als Basis für weitere Untersuchungen geeignet ist.