Matthias Unseld

Angiogenesis in cancer: anti-VEGF escape mechanisms

It is now widely accepted that tumor-angiogenesis plays a crucial role in tumor growth, tumor propagation and metastasis formation. Among several angiogenic activators, the vascular endothelial growth factor (VEGF) and its receptors represent one of the major inducers of tumor angiogenesis. Thus, this system has become the focus of therapeutic interventions, which led to the approval of the anti-VEGF blocking antibody bevacizumab and the VEGFR-2 pathway inhibitors pazopanib, sorafenib and sunitinib. However, not every cancer patient benefits from such treatment or finally becomes resistant to anti-VEGF approaches; others are suffering from adverse effects. Thus, there is an urgent need for a better understanding of VEGF-independent mechanisms leading to angiogenesis in cancer. This review focuses on anti-VEGF escape mechanisms of tumor cells and its microenvironment.

Suicidal ideation and temperament: An investigation among college students

BACKGROUND Suicide is a major health problem accounting for up to 1.5 percent of all deaths worldwide and represents one of the most common causes of death in adolescents and young adults. A number of studies has been performed to establish risk factors for suicide in patients with psychiatric disorders including temperamental features. This study set out to assess the relationship between suicidal ideation and temperament in young adults. METHODS A cross-sectional sample of healthy college students (n=1381) was examined using a self-rating questionnaire. Suicidal ideation, social background, educational status, substance abuse, and affective temperament according to TEMPS-M were assessed. Predictors of lifetime suicidal ideation were examined in multivariate logistic regression analyses. RESULTS Suicidal ideation was reported by 12.5% of all subjects at some point in their life and was higher in nicotine dependents, youth with alcohol related problems and users of illicit substances as well as in youth with lower educational status. Lifetime suicidal ideation was associated with the anxious, depressive and cyclothymic temperament in both sexes and the irritable temperament in males. These results remained significant after adjustment for smoking status, frequency of alcohol consumption, drug experience and educational status in a multivariate logistic regression analysis. LIMITATIONS The use of self-rating instruments always reduces objectivity and introduces the possibility of misreporting. CONCLUSIONS Considering the fact that many subjects completing suicide have never been diagnosed with mental disorders it might be reasonable to include an investigation of temperament in screenings for risk of suicide. This might be especially useful for health care professionals without mental health care background.

Soluble Carcinoembryonic Antigen Activates Endothelial Cells and Tumor Angiogenesis

Carcinoembryonic antigen (CEA, CD66e, CEACAM-5) is a cell-surface-bound glycoprotein overexpressed and released by many solid tumors that has an autocrine function in cancer cell survival and differentiation. Soluble CEA released by tumors is present in the circulation of patients with cancer, where it is used as a marker for cancer progression, but whether this form of CEA exerts any effects in the tumor microenvironment is unknown. Here, we present evidence that soluble CEA is sufficient to induce proangiogenic endothelial cell behaviors, including adhesion, spreading, proliferation, and migration in vitro and tumor microvascularization in vivo. CEA-induced activation of endothelial cells was dependent on integrin β-3 signals that activate the focal-adhesion kinase and c-Src kinase and their downstream MAP-ERK kinase/extracellular signal regulated kinase and phosphoinositide 3-kinase/Akt effector pathways. Notably, while interference with VEGF signaling had no effect on CEA-induced endothelial cell activation, downregulation with the CEA receptor in endothelial cells attenuated CEA-induced signaling and tumor angiogenesis. Corroborating these results clinically, we found that tumor microvascularization was higher in patients with colorectal cancer exhibiting higher serum levels of soluble CEA. Together, our results elucidate a novel function for soluble CEA in tumor angiogenesis.

The concept of temperament in psychoactive substance use among college students

BACKGROUND Substance abuse is among the leading causes of preventable diseases and premature death but reasons and conditions leading to substance abuse are complex and multifaceted. Different models of abuse and dependence assume an underlying emotional vulnerability. Individual behavioral and emotional reactivity patterns of personality are considered in the concept of temperament but studies linking different types of temperament with substance use are rare. METHODS In this study we investigated 1380 inhabitants (59.7% females; 40.3% males) of residential student homes in Austria, using Akiskals TEMPS-M auto-questionnaire. Further, we administered the CAGE- and the HSI-questionnaire and assessed other psychoactive substance use to examine associations between traits of temperament and substance abuse using ordered logistic regression. RESULTS Temperaments follow different distributions in both genders: Women have higher scores on the depressive, cyclothymic, and anxious subscales and lower scores on the hyperthymic scale than men. The cyclothymic and particularly irritable temperament serve as predictors of self-reported nicotine dependence, alcohol abuse and cannabis use. Interestingly, the depressive temperament seems to be protective against self-reported cannabis use. LIMITATIONS Substance abuse assessment is based on self-reports only and urine drug and blood tests were not performed. Also, the history of substance abuse is not documented thus temperamental factors could have been influenced by substance abuse if the time of onset was in early adolescence. The study design was cross-sectional, thus limiting causal interpretations. CONCLUSIONS It might be important to consider temperamental traits as protective- and risk factors in the etiology, prevention and therapy of substance abuse in future.

Targeting of VEGF-dependent transendothelial migration of cancer cells by bevacizumab

Cancer progression is often associated with the formation of malignant effusions. Vascular endothelial growth factor (VEGF) is a major regulator of vascular permeability and has been implicated as mediator of tumor progression.

The urokinase receptor (CD87) represents a central mediator of growth factor-induced endothelial cell migration

Angiogenesis, the sprouting of blood vessels form pre-existing vasculature after injury or in neoplastic diseases, is initiated by growth factor-induced endothelial cell migration. Recently, the major angiogenic growth factor VEGF165 has become the target of therapeutic interventions. However, this approach has been clinically proven to be of limited efficacy, which might be due to the fact that tumour angiogenesis is not only induced by VEGF, but also by a variety of other growth factors. Thus, the identification of a common downstream mediator of growth-factor-induced endothelial cell migration is mandatory to effectively interfere with (tumour-) angiogenesis. We found that the urokinase-type plasminogen activator (uPA)-system, which affects proteolytic as well as adhesive capacities, represents an essential regulatory mechanism in growth factor-induced endothelial cell migration and invasion. This mechanism was not limited to VEGF165, but mediated pro-angiogenic endothelial cell behaviour induced by various growth factors. Thus, VEGF165, VEGF-E, FGF-2, EGF as well as HGF induced a PI3k-dependent activation of pro-uPA when bound to uPAR, which led to an increase in cell surface fibrinolytic activity. As a consequence, uPAR became internalised and redistributed via LDLR-proteins. Interference with these events led to a reduced migratory response of endothelial cells towards VEGF in vitro as well as endothelial cell invasion in vivo. These data give first evidence that the uPA-system, which represents the only level-of-evidence-1 cancer biomarker system for prognosis and/or prediction in node negative breast cancer, might directly affect (tumour-) angiogenesis.

Integrins in the Spotlight of Cancer

Integrins are heterodimeric cell surface receptors that bind to different extracellular ligands depending on their composition and regulate all processes which enable multicellular life. In cancer, integrins trigger and play key roles in all the features that were once described as the Hallmarks of Cancer. In this review, we will discuss the contribution of integrins to these hallmarks, including uncontrolled and limitless proliferation, invasion of tumor cells, promotion of tumor angiogenesis and evasion of apoptosis and resistance to growth suppressors, by highlighting the latest findings. Further on, given the paramount role of integrins in cancer, we will present novel strategies for integrin inhibition that are starting to emerge, promising a hopeful future regarding cancer treatment.

CD98hc (SLC3A2) drives integrin-dependent renal cancer cell behavior

BackgroundOverexpression of CD98hc (SLC3A2) occurs in a variety of cancers and is suspected to contribute to tumor growth. CD98, a heterodimeric transmembrane protein, physically associates with certain integrin β subunit cytoplasmic domains via its heavy chain, CD98hc. CD98hc regulates adhesion-induced intracellular signal transduction via integrins, thereby, affecting cell proliferation and clonal expansion. Disruption of CD98hc led to embryonic lethality in mice (E 3.5 and E 9.5) and CD98hc −/− embryonic stem cell transplantation failed to form teratomas, while CD98hc over-expression in somatic cells resulted in anchorage-independent growth. However, it is unclear whether interference with CD98hc expression tumor cell behavior.MethodsRenal cell cancer cell lines have been used to determine the effect of CD98hc expression on cancer cell behavior using cell adhesion, cell trans-migration and cell spreading assays. Flow cytometric analysis was performed to study the rate of apoptosis after detachment or serum starvation. shRNA-lentiviral constructs were used to stably knockdown or reconstitute full length or mutated CD98hc. The role of CD98 as a promotor of tumorigenesis was evaluated using an in in vivo tumor transplantation animal model. Immunohistochemical analysis was performed to analyze cell proliferation and CD98 expression in tumors.ResultsThis report shows that CD98hc silencing in clear cell renal cancer cells reverts certain characteristics of tumorigenesis, including cell spreading, migration, proliferation and survival in vitro, and tumor growth in vivo. Acquisition of tumorigenic characteristics in clear cell renal cancer cells occurred through the integrin binding domain of CD98hc. A CD98hc/integrin interaction was required for adhesion-induced sustained FAK phosphorylation and activation of the major downstream signaling pathways PI3k/Akt and MEK/ERK, while overexpression of a constitutive active form of FAK rescued the CD98hc deficiency.ConclusionsIn this study we demonstrate that loss of CD98hc blocks tumorigenic potential in renal cell cancer.

Baseline carcinoembryonic antigen (CEA) serum levels predict bevacizumab-based treatment response in metastatic colorectal cancer

Carcinoembryonic antigen (CEA) affects tumorigenesis by enhancing tumor cell survival and by inducing tumor angiogenesis. This study aimed to evaluate baseline CEA serum levels to predict bevacizumab‐based therapy effect and survival in patients with metastatic colorectal cancer (mCRC). Two hundred and ninety eight mCRC patients receiving chemotherapy plus either bevacizumab or cetuximab were analyzed in a retrospective study. Disease control (DC), progression‐free survival (PFS), and overall survival were assessed and related to pretreatment CEA serum levels. Patients with baseline CEA serum levels below the statistical median of 26.8 ng/mL (group I) were compared with patients with higher CEA levels (group II). The cetuximab‐based treatment cohort was analyzed for specificity assessment of CEA to predict the anti‐vascular endothelial growth factor effect in mCRC. Baseline CEA serum levels inversely correlated with therapeutic response in patients receiving bevacizumab‐based treatment (disease control rate, 84% vs 60%), inversely correlated with median PFS leading to a median PFS benefit of 2.1 months for patients in group I when compared with group II, as well as inversely correlated with median overall survival (37.5 months vs 21.4 months). In an independent cohort of 129 patients treated with cetuximab‐based therapy, no association of therapeutic response or PFS with CEA serum levels was found. As expected, baseline CEA levels were prognostic for mCRC. These data give first evidence that baseline serum CEA levels might constitute an important predictor for the efficacy of first‐line bevacizumab‐based therapy in patients with mCRC.

The brief TEMPS-M temperament questionnaire: A psychometric evaluation in an Austrian sample.

• Temperament traits are considered as dispositions to mood states and other psychopathological conditions.