TLR2 2029C/T and TLR3 1377C/T and -7C/A Polymorphisms Are Associated with the Occurrence of Abdominal Aortic Aneurysm.

TLRs are a family of signaling sensors that play a crucial role in the host immune response and are involved in the modulation of inflammatory processes. To study their contribution to abdominal aortic aneurysm (AAA) formation and development, we determined the frequency of TLR2, TLR3, TLR4, and TLR9 single-nucleotide polymorphisms (SNPs) and investigated the association between polymorphisms and the risk of AAA incidence. A total of 104 patients with AAAs and 112 healthy, unrelated volunteers were screened for the presence of TLR2 (2029C/T and 2258G/A), TLR3 (1377C/T, 1234C/T, and -7C/A), TLR4 (896A/G, 1196C/T, and 3266G/A), and TLR9 (-1237T/C, -1486T/C, 1174G/A, and 2848C/T) SNPs by using PCR-RFLP analysis. The heterozygous genotype of the TLR2 2029C/T SNP was more common in patients with AAA than in healthy subjects (p < 0.0001) and was associated with at least an 8-fold increased risk of AAA incidence (p < 0.001). The wild-type genotype of the TLR3 -7C/A SNP was associated with a 3-fold increased risk of hypertension (p = 0.026). The heterozygous TLR3 genotype 1377C/T and -7C/A SNPs were less common in patients with AAA than in healthy subjects (p < 0.0001 and p = 0.0004, respectively) and were associated with a decreased risk of AAA occurrence (p < 0.001 and p = 0.0012, respectively). No relation to AAA risk was found for TLR4 SNPs. Heterozygous genotypes of the TLR2 2029C/T and TLR3 1377C/T and -7C/A SNPs may serve as genetic biomarkers of AAA incidence.

Left Renal Vein Division for Juxtarenal Aortic Exposure: Influence on Renal Function and Role of the Communicating Lumbar Vein.

BACKGROUND: In this study, we evaluate the outcome of renal function in patients undergoing juxtarenal abdominal aortic aneurysm repair with or without division of the left renal vein with special focus on the role of the communicating lumbar vein. METHODS: A retrospective analysis of prospectively collected data of 110 patients undergoing elective juxtarenal abdominal aortic aneurysm repair between 2000 and 2018 was performed. The demographic characteristics and comorbidities were reviewed in detail and the renal function was analysed pre- and post-operatively. The cohort of patients was split into group A (left renal vein divided) and B (left renal vein mobilised). Group A was further sub-analysed regarding the presence of a communicating lumbar vein on preoperative imaging data (group A+ = vein present, group A- = no communicating lumbar vein present). RESULTS: The patients were matched well regarding their demographic characteristics and comorbidities. In the analysis of renal function, no statistically significant difference could be detected between group A and B. In the sub-analysis of group A, the group with a communicating lumber vein (group A+) turned out to have a significantly better renal function in the long term (sCrea 0.87 vs. 1.51; p = 0.016). CONCLUSION: Ligation of the left renal vein is a safe procedure in surgery of juxtarenal aortic aneurysms regarding the outcome of the renal function. A communicating lumbar vein between the left renal vein and the left ascending lumbar vein seems to play a key role to provide venous drainage after division of the left renal vein.

Abdominal aortic aneurysm and virus infection: A potential causative role for cytomegalovirus infection?

An abdominal aortic aneurysm (AAA) is a multifactorial disease with a variety of genetic and environmental risk factors, but the exact mechanism of AAA formation and progression is still not well understood. The present study investigated the frequency of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and papillomavirus types 6 and 11 (HPV6 and HPV11), their impact on clinical manifestations of cardiovascular diseases, and their possible association with inflammation in patients with AAA and healthy volunteers. Genotyping of CMV UL75, EBV LMP-1, and HPV6, and HPV11 E6 was performed by polymerase chain reaction (PCR), while the viral DNA loads were measured by quantitative real-time PCR. Cytokine levels were determined by enzyme-linked immunosorbent assays. The CMV UL75 was detected more frequently in the blood of patients with AAA than in the blood of healthy volunteers (32.7% vs. 6.3%, p < .0001). Neither EBV LMP-1 nor HPV6 E6 was found in blood and aortic wall biopsies, while the HPV11 E6 was detected in 36.4% of AAA walls. The CMV infection in patients with AAA was associated with an increased risk of hypertension and coronary artery disease (OR, 9.057; 95% CI, 1.141-71.862; p = .037; and OR, 2.575; 95% CI, 1.002-6.615; p = .049, respectively). Additionally, CMV-infected patients with AAA had higher tumor necrosis factor-α levels compared with noninfected subjects (p = .017). Our findings suggest that CMV infection can stimulate local inflammation in the aorta but is not a direct cause of most abdominal aortic aneurysms.

Insight into the expression of toll-like receptors 2 and 4 in patients with abdominal aortic aneurysm.

An abdominal aortic aneurysm (AAA) is a relatively common, life-threatening disease prevalent in persons over the age of 65. In recent years, an increasing number of studies have suggested that pattern-recognition receptors (PRRs), including Toll-like receptors (TLRs), may serve as important regulators in the development of AAAs. In this study, we evaluated the TLR2 and TLR4 expression in the aortic wall and blood of patients with AAA. The TLR2 and TLR4 mRNA expression were significantly higher in the blood of patients with AAA than in the blood of healthy volunteers (p = 0.009 and p = 0.010, respectively). The expression of TLR2 and TLR4 transcripts was also higher in the blood compared with the aortic wall tissue of AAA patients (p = 0.001 for both). Higher TLR2 protein expression was observed in the aortic wall of AAA patients compared with the blood (p = 0.026). A significantly higher concentration of TNF-α and IL-4 in patients with AAA than in healthy volunteers (p < 0.001 for both) was noticed. This study suggests that TLR2 may play a role in the inflammatory response in the aorta, both locally and systemically, in patients with AAA.

Analysis of host Toll-like receptor 3 and RIG-I-like receptor gene expression in patients with abdominal aortic aneurysm.

OBJECTIVE: Abdominal aortic aneurysm (AAA) is a vascular disease relatively common in the elderly population. Although some events that contribute to the development and progression of AAA are known, there are limited data examining the association of Toll-like receptor 3 (TLR3) and RIG-I-like receptor expression with the pathogenesis of AAAs. In this study, we investigated the gene and protein expression of TLR3 and RIG-I-like receptors (RIG-I and MDA5) in aortic wall and blood of AAA patients and examined the relationship between their expression and immune response. METHODS: Total RNA was extracted from aortic wall tissues and blood samples collected from 20 patients with AAA and blood samples of 17 healthy volunteers without aortic aneurysm. To evaluate the DDX58 (RIG-I), IFIH1 (MDA5), and TLR3 gene expression level, quantitative real-time polymerase chain reaction was used. Extracellular cytokine and pattern recognition receptor levels were quantified by enzyme-linked immunosorbent assays. RESULTS: TLR3, RIG-I, and MDA5 were constitutively expressed in both aortic tissues and blood samples from AAA patients and healthy volunteers. In patients with AAA, higher TLR3 expression in aortic tissues than in blood was found (P = .004). The DDX58 messenger RNA expression was higher in blood of patients with AAA compared with healthy subjects (P = .021). A significantly higher level of plasma interleukin 4 was noticed in patients with AAA than in healthy individuals (P = .008). CONCLUSIONS: This study suggests that RIG-I and TLR3 seem to be important factors in the pathogenesis of AAA.

NGAL and MMP-9/NGAL as biomarkers of plaque vulnerability and targets of statins in patients with carotid atherosclerosis.

BACKGROUND: Neutrophil gelatinase associated lipocalin (NGAL) is expressed in atherosclerotic lesions and was recently implicated in the pathogenesis of cardiovascular pathologies. Statins are known to exert stabilizing effects on atherosclerotic plaque. The aims of our study were (1) to investigate the association of serum NGAL and metalloproteinase (MMP)-9/NGAL complex with the vulnerability of the atherosclerotic plaque, and (2) to reveal the effects of statin treatment on circulating NGAL and MMP-9/NGAL levels in patients with carotid artery stenosis. METHODS: We examined the levels of NGAL and MMP-9/NGAL in blood samples from 136 patients with carotid artery stenosis by specific enzyme-linked immunosorbent assays. RESULTS: Patients with vulnerable plaques, as determined by ultrasound (plaques with decreased echogenicity) and histological analysis (type VI according to the classification of American Heart Association [AHA]), displayed the highest levels of NGAL (both p<0.0001) and MMP-9/NGAL complex (p=0.0004 and p=0.004, respectively). Moreover, patients with symptomatic carotid atherosclerosis had significantly higher NGAL levels compared to asymptomatic patients (p=0.0007). The statin-treated group (n=108) demonstrated lower NGAL (73.9 vs. 128.0 µg/L, p<0.0001) and MMP-9/NGAL (28.9 vs. 40.6 µg/L, p=0.046) as compared to the non-statin group (n=28). Furthermore, in multivariate regression analysis NGAL, but not MMP-9/NGAL levels, were independently associated with symptomatic carotid artery stenosis. In addition, statin treatment was independently associated with lower NGAL levels. CONCLUSIONS: Circulating NGAL and MMP-9/NGAL are associated with plaque vulnerability in patients with carotid artery stenosis. Statin treatment could contribute to plaque stabilization by reducing circulating NGAL and MMP-9/NGAL levels.

The cell-wall active mannuronan C5-epimerases in the model brown alga Ectocarpus: From gene context to recombinant protein.

Mannuronan C5-epimerases (ManC5-Es) catalyze in brown algae the remodeling of alginate, a major cell-wall component which is involved in many biological functions in these organisms. ManC5-Es are present as large multigenic families in brown algae, likely indicating functional specificities and specializations. ManC5-Es control the distribution pattern of (1-4) linked ß-d-mannuronic acid (M) and α-l-guluronic acid (G) residues in alginates, giving rise to widely different polysaccharide compositions and sequences, depending on tissue, season, age, or algal species. As such they are also a source of powerful new tools for the biotechnological and enzymatic processing of alginates, to match the growing interest for food hydrocolloids and in biomedical and nanotechnological applications. We report here the first heterologous production of a ManC5-E of brown algal origin that is successfully refolded in an active form. The activity was measured by 1H NMR and by an indirect enzymatic assay using a known bacterial alginate lyase. The transcript expression as a function of the developmental program of the brown alga Ectocarpus, together with the bioinformatic analyses of the corresponding gene context of this multigenic family, is also presented.

Sinusoidal obstruction syndrome impairs long-term outcome of colorectal liver metastases treated with resection after neoadjuvant chemotherapy.

BACKGROUND: Chemotherapy-induced liver injury is a considerable problem in patients undergoing surgery for colorectal liver metastases, since an increase in postoperative morbidity and mortality has been observed. We investigated whether liver damage had further implications on long-term outcome in these patients. MATERIALS AND METHODS: Liver specimens from 196 patients resected for colorectal liver metastases were evaluated for chemotherapy-associated hepatic damage in the nontumorous liver. Injury patterns were correlated with recurrence free (RFS) and overall survival (OS). Factors leading to sinusoidal injury were identified. RESULTS: Patients who developed grade 2 or 3 sinusoidal dilatation had a significantly shorter RFS (hazard ratio [HR] 2.05; 95% confidence interval [95% CI] 1.23-3.39, P = .005) and OS (HR 2.90; 95% CI 1.61-6.19, P < .001), compared to patients without this alteration. Those patients also had significantly more intrahepatic recurrences (66.7% vs 30.5%, P = .003). Other patterns of chemotherapy-associated liver damage (nonalcoholic steatohepatitis, fibrosis) were not associated with impaired survival. Factors indicating sinusoidal injury were oxaliplatin-based chemotherapy, tumor size >5 cm, and elevated alkaline phosphatase or gamma glutamyltransferase. CONCLUSIONS: Sinusoidal obstruction syndrome due to oxaliplatin-based chemotherapy may not only compromise perioperative outcome, but can lead to early recurrence and decreased survival in the long term. Strategies to prevent this condition are clearly needed.

Application of diffusion-edited NMR spectroscopy for selective suppression of water signal in the determination of monomer composition in alginates.

Alginate is a linear copolymer of 1-4 linked ß-D-mannuronic acid (M) and 1-4 linked α-L-guluronic acid (G). The physical properties of these polysaccharides such as gel properties and viscosity are largely correlated to the monomer composition (M/G ratio), the sequence of the polymer and the molecular weight. Determination of the M/G ratio is therefore important and NMR spectroscopy is among the most common methods used to accurately obtain this ratio. Instead of using time consuming, possibly sample altering, acid hydrolysis to reduce the viscosity of the alginate sample prior to analysis, samples of low concentrations can be used. However, this results in a water peak in the NMR spectrum that is several orders of magnitude larger than the alginate signals and water suppression is required. In this article, a diffusion-edited NMR experiment that suppresses the water peak while retaining the signals of interest has been used to enable correct M/G ratio determination. This approach exploits the difference in translational diffusion between the larger alginate molecules and the smaller water molecules. Using this method, the monomer composition of 20 different alginate powders was determined. The diffusion parameters were optimized to allow measurement for samples covering a large range of M/G ratios and viscosities. Thus, such method should be useful for analyzing large numbers of unknown alginate samples using, for example, automation procedures.

Polymorphisms in the IL-6 and TNF-α gene are associated with an increased risk of abdominal aortic aneurysm.

BACKGROUND: An abdominal aortic aneurysm (AAA) is a complex disease of the aging population that is associated with inflammation and the cellular immune response. To investigate the influence of interleukin (IL)-6 and tumor necrosis factor (TNF)-α single nucleotide polymorphisms (SNPs) on the risk of AAA formation and progression, the frequency of AAA and its associated risk factors were determined. METHOD: Four SNPs in the IL-6 (-174G/C, rs1800795; -572G/C, rs1800796) and TNF-α (-238G/A, rs361525; -308G/A, rs1800629) genes were studied by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in patients with AAA and healthy volunteers. The mRNA expression and plasma IL-6 and TNF-α levels were also determined. RESULTS: A mutation detected in at least one allele of the IL-6 -174G/C SNP was associated with a 2-fold increased risk of AAA occurrence (OR: 2.08; 95% CI: 1.15-3.76; p = 0.014, in the dominant model). An increased risk of AAA incidence among heterozygous carriers of the TNF-α - 308G/A genotype was observed (OR: 2.06; 95% CI: 1.17-3.62; p = 0.011, in the overdominant model). The wild-type genotypes of the IL-6 -174G/C and the TNF-α -308G/A SNPs coexisted more frequently in healthy subjects than in AAA patients and was associated with decreased risk of AAA (p < 0.001). Moreover, elevated levels of IL-6 and TNF-α were associated with an increased risk of hypertension (p < 0.001 and p = 0.022, respectively). CONCLUSIONS: The IL-6 -174G/C and the TNF-α -238G/A gene polymorphisms are associated with an increased risk of abdominal aortic aneurysm development.

Liver resection remains a safe procedure after neoadjuvant chemotherapy including bevacizumab: a case-controlled study.

OBJECTIVE: This study was conducted to analyze if the combination of Bevacizumab with standard chemotherapy increases postoperative morbidity and mortality after resection of colorectal liver metastases as compared with resection after chemotherapy alone. Parameters contributing to an increased morbidity were evaluated. SUMMARY BACKGROUND DATA: Most patients referred for colorectal liver metastases are treated with neoadjuvant chemotherapy before hepatic surgery. Targeted agents like the vascular endothelial growth factor-antagonist Bevacizumab are increasingly added to standard therapy to prolong survival; however, little is known about the consequences of this policy in the perioperative period. METHODS: One hundred-two patients treated between 2005 and 2009, who received neoadjuvant chemotherapy combined with Bevacizumab (CHT + B) were identified. A cohort of 112 patients treated without chemotherapy alone before resection served as the control group (CHT). Complications were graded within an established staging system and the therapeutic consequences were laid down. Uni- and multivariate analysis of factors contributing to postoperative complications in the CHT + B group was performed using a logistic regression model. RESULTS: Postoperative complications occurred in 45 (44%, CHT + B) and 38 (34%, CHT) patients, respectively (P = 0.216). The incidence of severe complications requiring surgical or radiologic intervention or leading to organ failure was 10.8% in the CHT + B group and 7.1% in the CHT group (P = 0.350). Increased age, low serum albumin, resection of more than 3 liver segments and synchronous bowel procedures requiring an anastomosis were associated with an increased morbidity rate in the multivariate regression analysis. No patient died in either group. CONCLUSIONS: The addition of Bevacizumab to standard chemotherapy before resection of colorectal liver metastases does not seem to increase postoperative morbidity. Caution should be given to extended resections >3 liver segments and synchronous bowel anastomoses.

Bevacizumab improves pathological response of colorectal cancer liver metastases treated with XELOX/FOLFOX.

BACKGROUND: Histological response of colorectal cancer liver metastases to chemotherapy may be graded based on the extent of tumor regression. The knowledge about the effect of bevacizumab, if given in addition to fluoropyrimidines and oxaliplatin, on tumor regression and its consequences on clinical outcome is limited. MATERIALS AND METHODS: Resected liver metastases from patients of 2 prospective nonrandomized trials (fluoropyrimidines and oxaliplatin +/- bevacizumab) were analyzed retrospectively. Histological response was analyzed according to an established tumor regression grading for colorectal cancer liver metastases. Tumor regression grades (TRGs) were correlated to progression-free and overall survival. RESULTS: Bevacizumab improved tumor regression to chemotherapy significantly. Improvement in histological response was translated into a significant prolongation of progression-free and overall survival. CONCLUSIONS: Classifying histological response based on tumor regression grades qualifies to predict the outcome of patients with colorectal cancer liver metastases. Tumor regression grading provides a standardized pathological response evaluation, against which radiologic response on chemotherapy including biologicals can be prospectively evaluated.

Author Correction: Organic Power Electronics: Transistor Operation in the kA/cm2 Regime.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Inverse probability of treatment analysis of open vs endovascular repair in ruptured infrarenal aortic aneurysm - Cohort study.

BACKGROUND: To compare open repair (OR) with EVAR for the management of ruptured infrarenal abdominal aortic aneurysms (RAAA) in a cohort study over a time period of 15 years with inverse probability of treatment weights. MATERIAL AND METHODS: From 2000/01 through 2015/12 136 patients were treated for RAAA, 98 (72.1%) underwent OR, 38 (27.9%) were treated with EVAR. Thirty-day and long-term mortality (survival) were analyzed in this IRB-approved retrospective cohort study. Treatment modalities were compared using inverse probability of treatment weights to adjust for imbalances in demographic data and risk factors. RESULTS: EVAR patients were older (75.11 ± 7.17 vs 69.79 ± 10.24; p=0.001). There was no statistical difference in gender, hypertension, COPD, CAD, or diabetes. GFR was significantly higher in OR patients (71.4 ± 31.09 vs. 53.68 ± 25.73). Postoperative dialysis was required more frequently in EVAR patients: 11% vs. 2% (p = 0.099). In the OR group, adjusted cumulative survival was 70.4% (61.1, 81.1) at 30 days, 47.0% (37.1, 59.6) at one year and 38.3% (28.6, 51.3) at 5 years. In the EVAR group the corresponding numbers were 77.0% (67.7, 87.5), 67.5% (57.0, 80.0) and 41.7% (30.4, 57.4), respectively. CONCLUSION: There is evidence for EVAR patients exhibiting a benefit in one-year survival, while patients treated with OR may have more favorable long-term survival given they survive for at least one year. Herein we provide a statistically rigorous comparison of OR and EVAR in short and long-term outcomes with up to 15 years of follow-up.

Influence of hepatic resection margin on recurrence and survival in intrahepatic cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a rare disease in the Western world, hence little is known about its optimal surgical management. We analyzed whether hepatic resection margin is a prognostic factor for local or distant recurrence and survival in patients resected with curative intent. METHODS: Seventy-four patients underwent potentially curative surgery for ICC at our institution from 1994 to 2007. Demographic, and tumor- and surgery-related details including hepatic resection margin were recorded, patients were followed up for recurrence and survival. All patients were resected using modern dissection devices (CUSA or Waterjet). RESULTS: Fifty-nine patients (80%) underwent R0 resection, 15 (20%) had a resection margin greater than 10 mm (wide margin, WM) and 38 (51%) between 1 and 10 mm (close margin, CM). In 14 patients (19%), hepatic resection margin was involved on histological examination; perioperative mortalities were excluded from analysis (n = 7). Forty-seven patients developed recurrence (WM, CM, and R1): hepatic recurrence was observed in 40%, 58%, and 50% of patients; extrahepatic spread occurred in 27, 16, and 14%; and 33, 26, and 36% had no recurrence of disease so far (P = 0.755). There was no difference between groups regarding local versus disseminated hepatic recurrence. Median recurrence free survival was 11.4 months (WM), 9.8 months (CM), and 9.9 months (R1), respectively (P = 0.880). Median overall survival was 27.2 months (WM), 29.7 months (CM), and not reached in the R1 group, (P = 0.350). CONCLUSION: Hepatic resection margin seems to play a minor role in the prognosis of ICC as long as complete tumor clearance can be achieved with a modern liver dissection technique.

Non-Linear Self-Heating in Organic Transistors Reaching High Power Densities.

The improvement of the performance of organic thin-film transistors is driven by novel materials and improved device engineering. Key developments are a continuous increase of the charge carrier mobility, a scale-down of transistor dimensions, and the reduction of contact resistance. Furthermore, new transistor designs such as vertical devices are introduced to benefit from drastically reduced channel length while keeping the effort for structuring moderate. Here, we show that a strong electrothermal feedback occurs in organic transistors, ultimately leading to output characteristics with regions of S-shaped negative differential resistance. For that purpose, we use an organic permeable-base transistor (OPBT) with outstanding current densities, where a strong and reproducible, non-linear electrothermal feedback is revealed. We derive an analytical description of the temperature dependent current-voltage behavior and offer a rapid investigation method for material systems, where a temperature-activated conductivity can be observed.

A Pulse-Biasing Small-Signal Measurement Technique Enabling 40 MHz Operation of Vertical Organic Transistors.

Organic/polymer transistors can enable the fabrication of large-area flexible circuits. However, these devices are inherently temperature sensitive due to the strong temperature dependence of charge carrier mobility, suffer from low thermal conductivity of plastic substrates, and are slow due to the low mobility and long channel length (L). Here we report a new, advanced characterization circuit that within around ten microseconds simultaneously applies an accurate large-signal pulse bias and a small-signal sinusoidal excitation to the transistor and measures many high-frequency parameters. This significantly reduces the self-heating and therefore provides data at a known junction temperature more accurate for fitting model parameters to the results, enables small-signal characterization over >10 times wider bias I-V range, with ~105 times less bias-stress effects. Fully thermally-evaporated vertical permeable-base transistors with physical L = 200 nm fabricated using C60 fullerene semiconductor are characterized. Intrinsic gain up to 35 dB, and record transit frequency (unity current-gain cutoff frequency, fT) of 40 MHz at 8.6 V are achieved. Interestingly, no saturation in fT - I and transconductance (gm - I) is observed at high currents. This paves the way for the integration of high-frequency functionalities into organic circuits, such as long-distance wireless communication and switching power converters.

Organic Power Electronics: Transistor Operation in the kA/cm2 Regime.

In spite of interesting features as flexibility, organic thin-film transistors have commercially lagged behind due to the low mobilities of organic semiconductors associated with hopping transport. Furthermore, organic transistors usually have much larger channel lengths than their inorganic counterparts since high-resolution structuring is not available in low-cost production schemes. Here, we present an organic permeable-base transistor (OPBT) which, despite extremely simple processing without any high-resolution structuring, achieve a performance beyond what has so far been possible using organic semiconductors. With current densities above 1 kA cm-2 and switching speeds towards 100 MHz, they open the field of organic power electronics. Finding the physical limits and an effective mobility of only 0.06 cm2 V-1 s-1, this OPBT device architecture has much more potential if new materials optimized for its geometry will be developed.

Antibodies directed against Lewis-Y antigen inhibit signaling of Lewis-Y modified ErbB receptors.

The majority of cancer cells derived from epithelial tissue express Lewis-Y (LeY) type difucosylated oligosaccharides on their plasma membrane. This results in the modification of cell surface receptors by the LeY antigen. We used the epidermal growth factor (EGF) receptor family members ErbB1 and ErbB2 as model systems to investigate whether the sugar moiety can be exploited to block signaling by growth factor receptors in human tumor cells (i.e., SKBR-3 and A431, derived from a breast cancer and a vulval carcinoma, respectively). The monoclonal anti-LeY antibody ABL364 and its humanized version IGN311 immunoprecipitated ErbB1 and ErbB2 from detergent lysates of A431 and SKBR-3, respectively. ABL364 and IGN311 blocked EGF- and heregulin-stimulated phosphorylation of mitogen-activated protein kinase [MAPK = extracellular signal-regulated kinase 1/2] in SKBR-3 and A431 cells. The effect was comparable in magnitude with that of trastuzumab (Herceptin) and apparently noncompetitive with respect to EGF. Stimulation of MAPK by ErbB was dynamin dependent and contingent on receptor internalization. ABL364 and IGN311 changed the intracellular localization of fluorescent EGF-containing endosomes and accelerated recycling of intracellular [(125)I]EGF to the plasma membrane. Taken together, these observations show that antibodies directed against carbohydrate side chains of ErbB receptors are capable of inhibiting ErbB-mediated signaling. The ability of these antibodies to reroute receptor trafficking provides a mechanistic explanation for their inhibitory action.

Adenosine receptors: G protein-mediated signalling and the role of accessory proteins.

Ever since the discovery of the effects of adenosine in the circulation, adenosine receptors continue to represent a promising drug target. Firstly, this is due to the fact that the receptors are expressed in a large variety of cells; in particular, the actions of adenosine (or, respectively, of the antagonistic methylxanthines) in the central nervous system, in the circulation, on immune cells and on other tissues can be beneficial in certain disorders. Secondly, there exists a large number of ligands, which have been generated by introducing several modifications in the structure of the lead compounds (adenosine and methylxanthine), some of them highly specific. Four adenosine receptor subtypes have been identified by molecular cloning; they belong to the family of G protein-coupled receptors, which transfer signals by activating heterotrimeric G proteins. It has been appreciated recently that accessory proteins impinge on the receptor/G protein interaction and thus modulate the signalling reaction. These accessory components may be thought as adaptors that redirect the signalling pathway to elicit a cell-specific response. Here, we review the recent literature on adenosine receptors and place a focus on the role of accessory proteins in the organisation of adenosine receptor signalling. These components have been involved in receptor sorting, in the control of signal amplification and in the temporal regulation of receptor activity, while the existence of others is postulated on the basis of atypical cellular reactions elicited by receptor activation.