A plasmonic metasurface reveals differential motility of breast cancer cell lines at initial phase of adhesion

A plasmonic metasurface composed of a self-assembled monolayer of gold nanoparticles allows for fluorescence imaging with high spatial resolution, owing to the collective excitation of localized surface plasmon resonance. Taking advantage of fluorescence imaging confined to the nano-interface, we examined actin organization in breast cancer cell lines with different metastatic potentials during cell adhesion. Live-cell fluorescence imaging confined within tens of nanometers from the substrate shows a high actin density spanning < 1 μm from the cell edge. Live-cell imaging revealed that the breast cancer cell lines exhibited different actin patterns during the initial phase of cell adhesion (∼ 1 h). Non-tumorous MCF10A cells exhibited symmetric actin localization at the cell edge, whereas highly metastatic MDA-MB-231 cells showed asymmetric actin localization, demonstrating rapid polarization of MDA-MB-231 cells upon adhesion. The rapid actin organization observed by our plasmonic metasurface-based fluorescence imaging provides information on how quickly cancer cells sense the underlying substrate.

Total thrombus-formation analysis system (T-TAS) can predict target lesion revascularization in patients undergoing endovascular therapy for critical limb ischemia

Background

Despite of the development of endovascular therapy (EVT), the frequency of target lesion revascularization (TLR) after EVT in patients with critical limb ischemia (CLI) is still high. Recent histrogical study suggested the possibility of thromboembolic phenomenon in the development of CLI; however, there is few monitoring system of total thrombogenicity in perioperative period of EVT in CLI patients. The total thrombus-formation analysis system (T-TAS), a novel system for quantitatively analyzing thrombus formation using microchips with thrombogenic surfaces (collagen plus tissue factor, atheroma [AR]-chip), is validated and can evaluate the total thrombogenicity.

Purpose

To investigate the utility of T-TAS parameters in predicting TLR after EVT in CLI patients.

Methods

We analyzed 27 CLI patients (45 lesions; aortoiliac 20%, femoropopliteal 40%, infrapopliteal 40%) who underwent EVT at our institution between January 2018 and December 2020. Patients undergoing hemodialysis were excluded. Blood sample was collected on the day of EVT and was used in T-TAS to compute the thrombus formation area under the curve (AUC; AUC for the first 30 minutes for AR tested at flow rate of 10 lL/min [AR10-AUC30]). We investigated the relationship between the AR10-AUC30 level and the occurrence of clinically-driven TLR, and the predictors of TLR among CLI patients.

Results

Study population had a mean age of 77 years, and 56% were male. During the follow-up period (mean 1.0±0.7 years), 11 lesions (24%) required clinically-driven TLR. The AR10-AUC30 level was significantly higher in patients requiring TLR than those without TLR (1783±121 vs. 1587±205; p&lt;0.01). The frequency of TLR significantly increased in association with a tertile of the AR10-AUC30 level (Figure 1, p for trend=0.003). As shown in Figure 2, univariate logistic regression analysis demonstrated male sex and the third tertile of the AR10-AUC30 level compared to its first or second tertiles were significantly associated with TLR in patients with CLI, whereas platelet count, PT-INR, APTT, and atherosclerotic risk factors including glycated hemoglobin, low-density lipoprotein cholesterol, and renal function were not. Multivariate logistic regression analysis also revealed that the AR10-AUC30 level ≥1707 (=its third tertile) as an independent predictor for TLR, even after adjusted by age and sex (OR=6.28, 95% CI=1.18–33.3, p=0.03).

Conclusions

In patients with CLI, the AR10-AUC30 level measured by the T-TAS may be a potential predictor to identify the high-risk patients requiring TLR after EVT. This finding suggests the hypercoagulability in CLI patients and that an anticoagulant agent following EVT may be useful in preventing a restenosis in CLI patients. Further study with a larger sample size is warranted to validate this finding.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

East Asian variant aldehyde dehydrogenase Type 2 genotype exacerbates myocardial ischemia/reperfusion injury in men among patients with ST-segment elevation myocardial infarction -sex differences-

Background

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) detoxifies toxic aldehydes including those generated during ischemia/reperfusion (I/R) injury in acute myocardial infarction. The deficient variant ALDH2 genotype (ALDH2*2) is prevalent among East Asians. We examined whether ALDH2*2 exacerbates I/R injury in Japanese patients with acute ST-segment elevation myocardial infarction (STEMI) utilizing Mendelian randomization.

Methods and results

The study subjects comprised 248 Japanese patients with STEMI (187 men and 61 women, mean age 67.1±11.5) who underwent successful primary percutaneous coronary intervention. Of these patients, 129 (52.0%) were the carriers of ALDH2*2 and 119 (48.0%) those of wild ALDH2*1/*1 on genotyping by direct application of the TaqMan polymerase chain system. There were no differences in clinical characteristics between the ALDH2*2 and ALDH2*1/*1 group except lower alcohol habit in the ALDH2*2 group. However, the peak plasma levels of creatine phosphokinase myocardial binding (CKMB), a marker of myocardial injury, were significantly higher (a median 234.0 vs 150.0 U/L, P&lt;0.001 in the ALDH2*2 group. Furthermore, the peak CKMB levels were higher in ALDH2*2 group in men (a median 2 75.0 vs 144.9 U/L, P&lt;0.001) but not in women (P=0.855) and there was a significant interaction between sex and ALDH2*2 on I/R injury (χ2=8.362, P=0.004).

Conclusions

The peak plasma levels of CKMB were higher in STEMI patients with ALDH2*2 than in those with ALDH2*1/*1 among men but not women. These findings identified deficient ALDH2 activity to be targeted for treatment of STEMI specifically in men with ALDH2*2.

Visual overview

Funding Acknowledgement

Type of funding source: None

Correction to: Reply to the letter: N-Butyl Cyanoacrylate-Lipiodol Mixture for Endovascular Purpose: Polymerization Kinetics Differences Between In Vitro and In Vivo Experiments

We would like to correct one of the references that was listed incorrectly in our article.

Tuning intercellular adhesion with membrane-anchored oligonucleotides

Adhesive interactions between cells play an integral role in development, differentiation and regeneration. Existing methods for controlling cell-cell cohesion and adhesion by manipulating protein expression are constrained by biological interdependencies, e.g. coupling of cadherins to actomyosin force-feedback mechanisms. We use oligonucleotides conjugated to PEGylated lipid anchors (ssDNAPEGDPPE) to introduce artificial cell-cell adhesion that is largely decoupled from the internal cytoskeleton. We describe cell-cell doublets with a mechanical model based on isotropic, elastic deformation of spheres to estimate the adhesion at the cell-cell interface. Physical manipulation of adhesion by modulating the PEG-lipid to ssDNAPEGDPPE ratio, and conversely treating with actin-depolymerizing cytochalasin D, resulted in decreases and increases in doublet contact area, respectively. Our data are relevant to the ongoing discussion over mechanisms of tissue surface tension and in agreement with models based on opposing cortical and cohesive forces. PEG-lipid modulation of doublet geometries resulted in a well-defined curve indicating continuity, enabling prescriptive calibration for controlling doublet geometry. Our study demonstrates tuning of basic doublet adhesion, laying the foundation for more complex multicellular adhesion control independent of protein expression.

P6513Temporal trends in coronary intervention strategies and the impact on one-year clinical events: data from a Japanese multi-center real-world cohort study

Background

While it is clear that device technology of percutaneous coronary intervention (PCI) has advanced over the course of the last 40 years and the evidence for improvements in the efficacy of PCI is clear, it is less clear whether the prognosis following PCI continues to improve year by year.

Methods

The Kumamoto Intervention Conference Study Real-World Registry is a multi-center registry that enrolls consecutive patients undergoing PCI in 17 centers in Kyushu area, Japan. To elucidate the clinical impact of recent changes in treatment strategies, 8,841 consecutive participants (historical PCI: n=4,038, enrolled between January 2013 and December 2014, and current PCI: n=4,803, between January 2015 and March 2017) with 1-year follow-up data were analysed. Baseline demographic data, cardiovascular risk factors, and the medication being taken at discharge were documented. The primary endpoint was defined as a major adverse cardiac event (MACE), comprising cardiovascular death or non-fatal MI, including stent thrombosis (ST), occurring within 1 year of PCI.

Results

Regarding the relationships between presenting symptoms and PCI status, ACS, STEMI, NSTEMI, and UAP were similarly common, but the proportion of patients with multi-vessel disease was lower and the proportion with type B2/C lesions was higher in the current PCI group (p=0.004 and p<0.001, respectively). The prevalences of left main trunk lesions and Killip classes III or IV were comparable between the groups, but in-stent restenotic lesions were significantly more frequent in the historical PCI group (p<0.001). In addition to the change in the DAPT regimen, more optimal medical therapy was introduced during this time period, including the use of β-blockers, ACE-Is, and statins.

The incidences of MACE were comparable between historical PCI and current PCI (2.2% vs. 2.1%, p=0.693), even though complex lesions were more frequent during the more recent period. During this period, the use of radial approaches, drug eluting stents, and coronary imaging increased, but the use of intra-aortic balloon pumping (IABP) or thromboaspiration decreased. The incidences of major adverse cardiac or cerebrovascular events (MACCE), cardiac death, non-fatal MI, and stent thrombosis were similar between the historical and current periods (Figure). Multivariate analysis for overall patients, after adjustment, showed that multi-vessel disease, type B2/C lesions, ACS, and DES use were significant independent predictors of MACE.

Figure 1. Comparison of Clinical Events

Conclusion

An improvement in the prognosis associated with PCI has not occurred in recent years. However, the lesions being treated are becoming more complex, and the selection of evidence-based approaches, the use of coronary imaging, and the optimal medication treatments may have contributed to comparable outcomes being maintained.

Acknowledgement/Funding

Daiichi Sankyo Co., Ltd. Japan.

Design of Bioartificial Pancreases From the Standpoint of Oxygen Supply

A bioartificial pancreas (BAP), in which islets of Langerhans (islets) are enclosed in a semipermeable membrane, has been developed to realize islet transplantation without the use of immunosuppressive drugs. Although recent progress in induced pluripotent stem (iPS) and embryonic stem (ES) cells has attracted attention owing to the potential applications of these cells as insulin-releasing cells, concerns about the safety of implantation of these cells remain. The use of the BAP has the advantage of easy removal if insulin-releasing cells derived from iPS/ES cells undesirably proliferate and form tumors in the BAP. Oxygen supply is a crucial issue for cell survival in BAPs as insufficient oxygen supply causes central necrosis of cell aggregates. In this study, we derived several simple equations considering oxygen supply in BAPs in order to provide insights into the rational design of three different types of BAPs (spherical microcapsules, cylindrical capsules, and planar capsules). The equations give (i) the thickness of a capsule membrane leading to no central necrosis of encapsulated cell aggregates as a function of the original size of the cell aggregate; (ii) the oxygen concentration profiles in BAPs; (iii) the effects of encapsulation of a cell aggregate on insulin release; (iv) the amount of encapsulated cells required to normalize blood glucose levels of a patient; and (v) the total volumes and sizes of BAPs. As an example, we used the equations in order to design three different types of BAPs for subcutaneous implantation.

Recurrent Spindle Cell Carcinoma Shows Features of Mesenchymal Stem Cells

This study investigated a case of spindle cell carcinoma (SpCC) in tongue pathological lesions. The patient experienced a local recurrence and distant metastasis after surgical intervention. Although standard chemotherapy was administered, a granulomatous mass continued to develop. This aggressive growth led to survival of the tumor. Secondary debulking surgery was performed to improve the patient's quality of life at the request of the patient. Using a tissue sample derived from the secondary debulking surgery, we performed an analysis of the tumor's cell surface antigens, differentiation potential, metastatic ability, and inhibition potential by anticancer reagents. In vitro analysis revealed that the cell population grown under adherent culture conditions expressed the mesenchymal stem cell (MSC) markers CD73, CD90, and CD105. The cell line established from this SpCC contained colony-forming unit fibroblasts (CFU-Fs) and exhibited multipotent differentiation into several mesenchymal lineages, including bone, cartilage, and fat. The SpCC cells also displayed vigorous mobilization. These characteristics suggested that they had the differentiation potential of mesenchymal cells, especially MSCs, rather than that of epithelial cells. The surgical specimen analyzed in this study resisted the molecular target reagent cetuximab, which is an epidermal growth factor receptor inhibitor. This clinical insight revealed that chemotherapy-resistant SpCC cells have different characteristics compared to most other cancer cells, which are sensitive to cetuximab. Our cell death assay revealed that SpCC cell death was induced by the anticancer drug imatinib, which is known to inhibit protein tyrosine kinase activity of ABL, platelet-derived growth factor receptor α (PDGFRα), and KIT. Here, we report recurrent SpCC with characteristics of MSCs and potential for treatment with imatinib.

Assessment of platelet-derived thrombogenicity with the total thrombus-formation analysis system in coronary artery disease patients receiving antiplatelet therapy

BACKGROUND

Accurate evaluation of thrombogenicity helps to prevent thrombosis and excessive bleeding. The total thrombus-formation analysis system (T-TAS) was developed for quantitative analysis of platelet thrombus formation by the use of microchips with thrombogenic surfaces (collagen, platelet chip [PL-chip]; collagen plus tissue factor, atherome chip [AR-chip]). We examined the utility of the T-TAS in the assessment of the efficacy of antiplatelet therapy in patients with coronary artery disease (CAD).

METHODS AND RESULTS

In this cross-sectional study, 372 consecutive patients admitted to the cardiovascular department were divided into three groups: patients not receiving any antiplatelet therapy (control, n = 56), patients receiving aspirin only (n = 69), and patients receiving aspirin and clopidogrel (n = 149). Blood samples were used for the T-TAS to measure the platelet thrombus-formation area under the curve (AUC) at various shear rates (1500 s(-1) [PL18 -AUC10 ] and 2000 s(-1) [PL24 -AUC10 ] for the PL-chip; 300 s(-1) [AR10 -AUC30 ] for the AR-chip). The on-clopidogrel platelet aggregation was measured by the use of P2Y12 reaction units (PRUs) with the VerifyNow system. The mean PL24 -AUC10 levels were 358 ± 111 (± standard deviation) (95% confidence interval [CI] 328.9-387.1) in the control group, 256 ± 108 (95% CI 230.5-281.5) in the aspirin group, and 113 ± 91 (95% CI 98.4-127.6) in the aspirin/clopidogrel group. In the aspirin/clopidogrel group, the PL24 -AUC10 was higher in poor metabolizers (PMs) with cytochrome P450 2C19(CYP2C19) polymorphisms (152 ± 112, 95% CI 103.4-200.6) than in the non-PM group (87 ± 74, 95% CI 73.8-100.2).

CONCLUSIONS

Our findings suggest that the PL24 -AUC10 level measured by the T-TAS is a potentially suitable index for the assessment of antiplatelet therapy in CAD patients.

Interaction of poly(ethylene glycol)-conjugated phospholipids with supported lipid membranes and their influence on protein adsorption

We studied real-time interaction between poly(ethylene glycol)-conjugated phospholipids (PEG-lipids) and a supported lipid membrane by surface plasmon resonance (SPR) spectroscopy to understand dynamic behaviors of PEG-lipids on living cell membranes. Supported lipid membranes formed on a hydrophobic surface were employed as a model of living cell membrane. We prepared three kinds of PEG-lipids that carried alkyl chains of different lengths for SPR measurements and also performed fluorescence recovery after photobleaching (FRAP) to study the influence of acyl chain length on dynamics on the supported membrane. PEG-lipids were uniformly anchored to lipid membranes with high fluidity without clustering. Incorporation and dissociation rates of PEG-lipids into supported membranes strongly depended on the length of acyl chains; longer acyl chains reduced the incorporation rate and the dissociation rate of PEG-lipid. Furthermore, protein adsorption experiment with bovine serum albumin indicated that PEG modification prevented the adsorption of bovine serum albumin on such supported membrane.

A DNA hybridization system for labeling of neural stem cells with SPIO nanoparticles for MRI monitoring post-transplantation

Neural stem cells (NSCs) demonstrate encouraging results in cell replacement therapy for neurodegenerative disorders and traumatic injury in the central nervous system. Monitor the survival and migration of transplanted cells would provide us important information concerning the performance and integration of the graft during the therapy time course. Magnetic resonance imaging (MRI) allow us to monitor the transplanted cells in a non-invasive way. The only requirement is to use an appropriate contrast agent to label the transplanted cells. Superparamagnetic iron oxide (SPIO) nanoparticles are one of the most commonly used contrast agent for MRI detection of transplanted cells. SPIO nanoparticles demonstrated to be suitable for labeling several types of cells including NSCs. However, the current methods for SPIO labeling are non-specific, depending mostly on electrostatic interactions, demanding relatively high SPIO concentration, and long incubation time, which can affect the viability of cells. In this study, we propose a specific and relatively fast method to label NSCs with SPIO nanoparticles via DNA hybridization. Two short single stranded DNAs (ssDNAs), oligo[dT]20 and oligo[dA]20 were conjugated with a lipid molecule and SPIO nanoparticle respectively. The labeling process comprises two simple steps; first the cells are modified to present oligo[dT]20 ssDNA on the cell surface, then the oligo[dA]20 ssDNA conjugated with SPIO nanoparticles are presented to the modified cells to allow the oligo[dT]20-oligo[dA]20 hybridization. The method showed to be non-toxic at concentrations up to 50 μg/mL oligo[dA]20-SPIO nanoparticles. Presence of SPIO nanoparticles at cell surface and cell cytoplasm was verified by transmission electron microscopy (TEM). SPIO labeling via DNA hybridization demonstrated to not interfere on NSCs proliferation, aggregates formation, and differentiation. NSCs labeled with SPIO nanoparticles via DNA hybridization system were successfully detected by MRI in vitro as well in vivo. Cells transplanted into the rat brain striatum could be detected by MRI scanning up to 1 month post-transplantation.

Cell patterning on polylactic acid through surface-tethered oligonucleotides

Polylactic acid (PLA) is a candidate material to prepare scaffolds for 3-D tissue regeneration. However, cells do not adhere or proliferate well on the surface of PLA because it is hydrophobic. We report a simple and rapid method for inducing cell adhesion to PLA through DNA hybridization. Single-stranded DNA (ssDNA) conjugated to poly(ethylene glycol) (PEG) and to a terminal phospholipid (ssDNA-PEG-lipid) was used for cell surface modification. Through DNA hybridization, modified cells were able to attach to PLA surfaces modified with complementary sequence (ssDNA'). Different cell types can be attached to PLA fibers and films in a spatially controlled manner by using ssDNAs with different sequences. In addition, they proliferate well in a culture medium supplemented with fetal bovine serum. The coexisting modes of cell adhesion through DNA hybridization and natural cytoskeletal adhesion machinery revealed no serious effects on cell growth. The combination of a 3-D scaffold made of PLA and cell immobilization on the PLA scaffold through DNA hybridization will be useful for the preparation of 3-D tissue and organs.

Abstract P1-07-02: Significance of RB-ZEB axis in EMT phenotype of breast cancer and inhibition of ZEB by CDK4/6 inhibitor

The retinoblastoma protein (pRB) is a key tumor suppressor that regulates the progression of cell cycles from G1 to S phase. pRB is often inactivated due to mutation, very low level expression or hyperphosphorylation by cyclin-dependent kinases (CDKs) in many cancers. We found that knockdown of pRB induced the expression of ZEB1 (zinc finger E-box binding homeobox 1), which is one of the transcriptional repressors of the E-cadherin gene, and led to epithelial-mesenchymal transition (EMT) through the ZEB-dependent pathways in breast cancer cells. EMT is defined by the loss of epithelial characteristics and the acquisition of a mesenchymal phenotype, and is associated with an invasive and metastatic potential in cancers. We found that siRNA-mediated depletion of ZEB in pRB-inactive cells suppressed cell invasiveness and proliferation and induced epithelial-cell marker expressions. We also found that knockdown of ZEB1 reduced the dissemination of breast cancer cells in bone marrow from primary tumors growing in mammary fat pads of nude mice. We then conducted a screen with an existing drug library for inhibitors of ZEB1 expressions and identified several hits, including CDK inhibitors. We confirmed that the CDK4/6 inhibitor, Palbociclib (PD0332991), suppressed breast cancer cell proliferation and invasiveness in vitro, and the treatment with the PD0332991 suppressed tumor growth in vivo using an orthotopic xenograft breast cancer model. In terms of cancer stemness, we found that the treatment of PD0332991 decreased the CD44+/CD24Low/- breast cancer stem cell population. We also determined that CDK4 inhibitors blocked tumorsphere formations, which are a characteristic of stem-like cancer cells. p16INK4a (p16) is an endogenous CDK4/6 inhibitor, and we found that knockdown of p16 increased the CD44+/CD24Low/- breast cancer stem cell population in estrogen receptor-negative breast cancer. CDK4/6 inhibitors appear to substitute for the p16 functions which suppress cancer stemness. Our findings indicate that the CDK4/6 inhibitor affects tumor progression, not only through cell cycle control, but also through the suppression of EMT and stem-like properties of cancer cells.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-02.

Ink4a/Arf(-/-) and HRAS(G12V) transform mouse mammary cells into triple-negative breast cancer containing tumorigenic CD49f(-) quiescent cells

Intratumoral heterogeneity within individual breast tumors is a well-known phenomenon that may contribute to drug resistance. This heterogeneity is dependent on several factors, such as types of oncogenic drivers and tumor precursor cells. The purpose of our study was to engineer a mouse mammary tumor model with intratumoral heterogeneity by using defined genetic perturbations. To achieve this, we used mice with knockout (−/−) of Ink4a/Arf, a tumor suppressor locus; these mice are known to be susceptible to non-mammary tumors such as fibrosarcoma. To induce mammary tumors, we retrovirally introduced an oncogene, HRAS(G12V), into Ink4a/Arf^−/− mammary cells in vitro, and those cells were inoculated into syngeneic mice mammary fat pads. We observed 100% tumorigenesis. The tumors formed were negative for estrogen receptor, progesterone receptor, and HER2. Further, they had pathological features similar to those of human triple-negative breast cancer (e.g. pushing borders, central necrosis). The tumors were found to be heterogeneous and included two subpopulations: CD49f⁻ quiescent cells and CD49f⁺ cells. Contrary to our expectation, CD49f⁻ quiescent cells had high tumor-initiating potential and CD49f⁺ cells had relatively low tumor-initiating potential. Gene expression analysis revealed that CD49f⁻ quiescent cells overexpressed epithelial-to-mesenchymal transition-driving genes, reminiscent of tumor-initiating cells and claudin-low breast cancer. Our animal model with intratumoral heterogeneity, derived from defined genetic perturbations, allows us to test novel molecular targeted drugs in a setting that mimics the intratumoral heterogeneity of human triple-negative breast cancer.

Effect of dielectric spacer thickness on signal intensity of surface plasmon field-enhanced fluorescence spectroscopy

Surface plasmon field-enhanced fluorescence spectroscopy (SPFS) combines enhanced field platform and fluorescence detection. Its advantages are the strong intensity of the electromagnetic field and the high signal/noise (S/N) ratio due to the localized evanescent field at the water/metal interface. However, the energy transfer from the fluorophore to the metal surface diminishes the fluorescence intensity, and this reduces the sensitivity. In this study, we tested whether polystyrene (PSt) could act as a dielectric layer to suppress the energy transfer from the fluorophore to the metal surface. We hypothesized that this would improve the sensitivity of SPFS-based immunoassays. We used α-fetoprotein (AFP) as a model tumor biomarker in the sandwich-type immunoassay. We determined the relationship between fluorescent signal intensity and PSt layer thickness and compared this to theoretical predictions. We found that the fluorescence signal increased by optimally controlling the thickness of the PSt layer. Our results indicated that the SPFS-based immunoassay is a promising clinical diagnostic tool for quantitatively determining the concentrations of low-level biomarkers in blood samples.

Surface plasmon resonance in monitoring of complement activation on biomaterials

When artificial materials come into contact with blood, various biological responses are induced. For successful development of biomaterials used in biomedical devices that will be exposed to blood, understanding and control of these interactions are essential. Surface plasmon resonance (SPR) spectroscopy is one of the surface-sensitive optical methods to monitor biological interactions. SPR enables real-time and in situ analysis of interfacial events associated with biomaterials research. In this review, we describe an SPR biosensor and its application to monitor complement activation onto biomaterials surface. We also discuss the effect of surface properties of the material on complement activation.

Complement activation on degraded polyethylene glycol-covered surface

Surface modification with polyethylene glycol (PEG) has been employed in the development of biomaterials to reduce unfavorable reactions. However, unanticipated body reactions have been reported, with activation of the complement system being suggested as having involvement in these responses. In this study, we prepared a PEG-modified surface on a gold surface using a monolayer of alpha-mercaptoethyl-omega-methoxy-polyoxyethylene. We observed neither protein adsorption nor activation of the complement system on the PEG-modified surface just after preparation. Storage of the PEG-modified surface in a desiccator under ambient light for several days or following ultraviolet irradiation, reflection-adsorption (FTIR-RAS) and X-ray photo spectrometry revealed deterioration of the PEG layer, which became a strong activator of the complement system through the alternative pathway.

Complement activation by polymers carrying hydroxyl groups

Hydrogels of polymers carrying surface hydroxyl groups strongly activate the complement system through the alternative pathway, although it has also been reported that solutions of polymers do not. To address these curious, inconsistent results, we examined the effect of polymer states, either immobilized on a surface or soluble in serum, on the complement activation using a surface plasmon resonance apparatus and enzyme-linked immunosorbent assay. We clearly showed that dextran- and poly(vinyl alcohol)-immobilized surfaces strongly activated the complement system but that soluble polymers could not, even when the amounts of the soluble polymers added to serum were 4-2000 times higher than those on the polymer-immobilized surfaces.

Surface plasmon resonance and surface plasmon field-enhanced fluorescence spectroscopy for sensitive detection of tumor markers

Surface plasmon resonance (SPR), which provides real-time, in situ analysis of dynamic surface events, is a valuable tool for studying interactions between biomolecules. In the clinical diagnosis of tumor markers in human blood, SPR is applied to detect the formation of a sandwich-type immune complex composed of a primary antibody immobilized on a sensor surface, the tumor marker, and a secondary antibody. However, the SPR signal is quite low due to the minute amounts (ng-pg/mL) of most tumor markers in blood. We have shown that the SPR signal can be amplified by applying an antibody against the secondary antibody or streptavidin-conjugated nanobeads that specifically accumulate on the secondary antibody. Another method employed for highly sensitive detection is the surface plasmon field-enhanced fluorescence spectroscopy-based immunoassay, which utilizes the enhanced electric field intensity at a metal/water interface to excite a fluorophore. Fluorescence intensity attributed to binding of a fluorophore-labeled secondary antibody is increased due to the enhanced field in the SPR condition and can be monitored in real time.

Multifunctional chimeric proteins for the sequential regulation of neural stem cell differentiation

Controlling the dynamics of growth factor signaling is a challenge in regenerative medicine for various tissues including the central nervous system. Here, we report on the development of the biomolecular system that facilitates sequential regulation of growth factor signals acting on neural stem/progenitor cells. Recombinant technology was employed to synthesize the multifunctional chimeric protein that contained multiple domains, including epidermal growth factor (EGF), ciliary neurotrophic factor (CNTF), globular capping domain, thrombin-cleavable sequence, and substrate-binding domain with affinity for Ni(II) ions. The chimeric protein is expected to expose CNTF upon elimination of the capping domain by digestion with endogenous thrombin in vivo. When the multifunctional chimeric protein was immobilized onto a substrate through the coordination of the substrate-binding domain with surface-immobilized Ni(II) ions, the substrate served to proliferate neural stem cells, maintaining the population of undifferentiated cells at 85%. This effect is primarily due to the activity of EGF, while CNTF activity is temporally veiled with the capping domain. Upon digesting the thrombin-cleavable sequence to remove the capping domain, the activity of CNTF emerged to induce differentiation of astrocytes in situ from the proliferated neural stem cells. The fraction of differentiated astrocytes reached 68% of total cells. These results demonstrate the feasibility of the system for controlling the dynamics of growth factor signals.

An outbreak of psittacosis in a bird park in Japan

An outbreak of psittacosis related to a bird park occurred in Matsue City, Shimane Prefecture, Japan, during winter 2001. Seventeen cases of psittacosis (12 visitors, three staff, and two student interns) were confirmed. A cohort study was conducted among the park staff and students to determine the risk factors for the development of acute serologically confirmed psittacosis (SCP) infection. Being 'bird staff' had an increased risk of SCP infection (RR 3.96, 95% CI 1.48-10.58). Entering the staff building, where ill birds were maintained without proper isolation, was also associated with an increased risk of SCP infection (RR 3.61, 95% CI 1.03-12.6). Isolation of ill birds and quarantine measures were found to be insufficient. Dehumidifiers and a high-pressure water spray under a closed ventilation environment may have raised the concentration of Chlamydophila psittaci in the hothouses. Bird park staff and visitors should be educated about psittacosis.

Oriented immobilization of epidermal growth factor onto culture substrates for the selective expansion of neural stem cells

To develop a culture substrate that allows efficient expansion of neural stem cells (NSCs), epidermal growth factor (EGF) was immobilized onto the Ni(II)-chelated surface of a glass-based substrate through coordination of Ni(II) to the histidine tag that was fused to the C-terminal of EGF using recombinant technology. For the preparation of the nickel-chelated surface, a thin gold layer was deposited to the glass surface, and then the self-assembled monolayer of alkanethiol terminated with trivalent carboxylic acids was formed on gold and chelated with Ni(II) ions. In the preparation of a monolayer, triethylene glycol-terminated alkanethiol was mixed with carboxylic acid-terminated alkanethiol at various compositions in order to reduce the non-specific adsorption of EGF. The surface analysis of the monolayers was performed by X-ray photoelectron spectroscopy, infrared reflection-absorption spectroscopy, and contact angle measurements. Surface plasmon resonance analyses and protein assays were performed for characterizing EGF-immobilized surfaces. The proliferation and differentiation of rat fetal NSCs were examined on the EGF-chelated substrates to assess quantitatively the effects of alkanethiol composition on the efficiency of stem cell amplification. It was shown that the amplification efficiency was dependent on the alkanethiol composition. This result could be attributed to the difference in the surface density of chelated EGF. Under the optimal condition, 98% of proliferated cells expressed NSC marker. In addition, these cells could be subcultured for further expansion, while retained their multipotency. We concluded that the substrate developed here provides the efficient method for the highly selective expansion of NSCs.

Effect of wettability and surface functional groups on protein adsorption and cell adhesion using well-defined mixed self-assembled monolayers

Self-assembled monolayers (SAMs) of alkanethiols, which can provide flat and chemically well-defined surfaces, were employed as model surfaces to understand cellular interaction with artificial materials. SAMs presenting a wide range of wettabilities were prepared by mixing two kinds of alkanethiols carrying terminal methyl (CH(3)), hydroxyl (OH), carboxylic acid (COOH), or amino (NH(2)) groups. Adhesion behavior of human umbilical vein endothelial cells (HUVECs) and HeLa cells on these mixed SAMs were examined. The number of adhered HUVECs reached a maximum on CH(3)/OH mixed SAMs with a water contact angle of 40 degrees , while cell adhesion increased with decreasing water contact angle up to 60-70 degrees and then leveled off on CH(3)/COOH and CH(3)/NH(2) mixed SAMs. Numbers of adhered HeLa cells showed a maximum on CH(3)/OH and CH(3)/COOH mixed SAMs with a water contact angle of 50 degrees . These facts suggest that cell adhesion is mainly determined by surface wettability, but is also affected by the surface functional group, its surface density, and the kinds of cells. The effect of exchange of adsorbed proteins on cell adhesion was also examined. HUVECs were cultured on the mixed SAMs preadsorbed with albumin. Cell adhesion was effectively prohibited on hydrophobic SAMs pretreated with albumin. Albumin strongly adsorbed and resisted replacement by cell adhesive proteins on hydrophobic SAMs. On the other hand, cells adhered to albumin-adsorbed hydrophilic SAMs. Displacement of preadsorbed albumin with cell adhesive proteins effectively occurs on these hydrophilic SAMs. This effect contributes to induce SAMs with moderate wettability to give suitable surfaces for cell adhesion.

Serine protease Omi/HtrA2 targets WARTS kinase to control cell proliferation

The serine protease Omi/HtrA2 was initially regarded as a proapoptotic molecule that proteolyses several proteins to induce cell death. Recent studies, however, indicate that loss of Omi protease activity increases susceptibility to stress-induced cell death. These complicated findings suggest that the protease activity of Omi is involved not only in apoptosis but also in cellular homeostasis. However, the targets which Omi uses to mediate this novel process are unknown. Previously, we showed that WARTS (WTS)/large tumor-suppressor 1 mitotic kinase interacts with the protein/discs-large protein/zonula (PDZ) domain of Omi and promotes its protease activity. We now report that WTS is a substrate for Omi protease activity, thus it is not only a regulator but also a downstream target of this protease. Interaction with Omi PDZ domain is required for WTS to be proteolysed. When caspase-9-deficient mouse embryonic fibroblasts (MEFs) were treated with staurosporine, WTS was proteolysed by activated endogenous Omi without induction of cell death. Therefore, protease activity of Omi and proteolysis of WTS are not necessarily required for cell death. We found that depletion of Omi from HeLa cells results in accelerated cell proliferation despite no significant change in the duration of mitosis. The depletion of WTS showed the same effect on S phase progression. Therefore, WTS proteolytic fragment(s) generated by Omi may act as an inhibitor of G1/S progression. Our data reveal a role for Omi-mediated processing of WTS in negative regulation of cell cycle progression at interphase, suggesting a novel function of Omi other than apoptosis.

Combinatorial protein display for the cell-based screening of biomaterials that direct neural stem cell differentiation

Neural stem cell (NSC) has emerged as a potential source for cell replacement therapy following traumatic injuries and degenerative diseases of the central nervous system. However, clinical applications of NSC further require technological advances especially for controlling differentiation of NSC. This study aimed at developing biomaterials that serve to expand undifferentiated NSC or to induce cells with specific phenotypes. Our approach is to construct composite biomaterials that consist of extracellular matrix components and growth factors. In order to optimize matrix-growth factor combinations, we conducted the parallel and rapid screening of composite biomaterials through assays using cell-based arrays. The photo-assisted patterning of an alkanethiol self-assembled monolayer was employed to achieve site-addressable combinatorial immobilization of natural and synthetic matrices incorporated with growth factors including epidermal growth factor (EGF), ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), and neurotrophin-3 (NT-3). NSC obtained from the rat embryonic striatum was cultured directly on the array to screen for cell adhesion, proliferation, and promotion of neuronal and glial specification. The results showed that the significant number of cells adhered to laminin-1, fibronectin, ProNectin, and poly(ethyleneimine). It was found that cells proliferated most extensively on a spot with immobilized EGF among the spots with different matrix-growth factor combinations. The results also showed that neuronal differentiation was promoted on the spots with immobilized NGF or NT-3, and astroglial differentiation with CNTF. Importantly, observed effects of growth factors were frequently altered depending on the type of co-immobilized matrices, suggesting synergic effects of adhesion and growth factor signals.

Surface plasmon resonance-based highly sensitive immunosensing for brain natriuretic peptide using nanobeads for signal amplification

In this study, we developed a surface plasmon resonance (SPR)-based sensing method with high sensitivity for the detection of brain natriuretic peptide (BNP), the level of which is a useful indicator of heart failure. In our system, BNP was detected by a sandwich-type immunoassay using two kinds of monoclonal antibodies: primary and secondary. The SPR signal was amplified by using streptavidin-conjugated nanobeads approximately 50 nm in diameter that specifically accumulated on the secondary antibody via biotin-avidin bonding. By this method, the SPR signals were highly intensified, and thus picogram levels (pg/ml) of BNP could be detected. The streptavidin nanobead amplification method realizes detection of very low levels of BNP, as is necessary for the clinical diagnosis. It is also expected that our streptavidin nanobead amplification method can be applicable to the detection of other hormones and tumor markers that are present in only low concentrations within the human body.

Impaired removal of 8-hydroxydeoxyguanosine induced by UVB radiation in naevoid basal cell carcinoma syndrome cells

BACKGROUND

The naevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by tumorigenesis such as multiple basal cell carcinomas, odontogenic keratocysts and developmental abnormalities such as calcified dural folds and rib-anomalies. Recently, it has been shown that ultraviolet (UV) B exposure produced more BCCs in ptch knockout mice than wild mice.

OBJECTIVES

To Investigate the role of UV in development of BCCs in NBCCS, cellular sensitivity to killing by UVB and removal of UVB-induced oxidative DNA damage were examined using fibroblasts derived from patients with NBCCS under physiologically relevant doses of UVB exposure.

PATIENTS AND METHODS

Three patients with NBCCS, a 59-year-old male patient, an 18-year-old boy and a 13-year-old boy were examined by photobiological analysis. Cellular sensitivity to killing by UVB and UVC and removal of oxidative DNA damage caused by UVB were tested using fibroblasts derived from these patients. We measured cellular 8-hydroxydeoxyguanosine (8-OHdG) after UVB exposure up to 24 h after UVB exposure using high-performance liquid chromatography.

RESULTS

All three cell strains derived from the patients with NBCCS were hypersensitive to killing by UVB (D10: 50-70% of normal) but not by UVC. After UVB exposure, the production of 8-OHdG increased dose dependently up to 3200 J m-2 in both NBCCS cells and normal cells. In normal cells, 8-OHdG after UVB exposure returned to its basal level during 24 h, whereas in NBCCS cells the amount of 8-OHdG after 800 J m-2 of UVB exposure did not return to its basal level even after 24 h. The result indicates the removal of 8-OHdG could be impaired in NBCCS cells. Ability in removal of thymine dimers of NBCCS cells was similar to that of normal cells.

CONCLUSIONS

Hypersensitivity to UVB can be one of the diagnostic tools of NBCCS for those whose clinical features have not yet completed. Hypersensitivity to cell killing and the impairment of removal of 8-OHdG after UVB exposure may play some role in developing BCCs and other tumours in NBCCS.

Splenic artery embolization before laparoscopic splenectomy in children

BACKGROUND

This study assessed the safety and utility of preoperative splenic artery embolization before laparoscopic splenectomy in children.

METHODS

Five young girls with a mean age of 13.2 years underwent laparoscopic splenectomies at the authors' institution from August 1998 to April 2003. Three of the patients had idiopathic thrombocytopenic purpura, and two had hereditary spherocytosis. Preoperative splenic artery embolization was performed the day before the surgery in all cases. The laparoscopic splenectomy was performed using traditional laparoscopic procedures and standard laparoscopic instruments with the patient in the right semilateral position.

RESULTS

The mean spleen weight was 252.6 g, and the mean length was 11.6 cm. All the patients reported postembolic pain, but not to a level unmanageable by intravascular narcotics. There were no severe complications in the splenic artery embolization. The laparoscopic splenectomies were completed in a mean of 211 min, with a mean estimated blood loss of 9 ml. None of the operations required conversion to traditional open laparotomy, and none of the patients died or experienced operative complications.

CONCLUSION

The authors concluded that splenic artery embolization is safe and useful as an adjuvant procedure performed before elective laparoscopic splenectomy in children.

Hand-assisted laparoscopic hepatectomy after partial splenic embolization

The case of a patient with hepatocellular carcinoma and thrombocytopenia secondary to liver cirrhosis who underwent successful hand-assisted laparoscopic hepatectomy after partial splenic embolization is described. A 67-year-old man with severe liver cirrhosis was admitted for treatment of hepatocellular carcinoma. His early phase of hepatic angiography showed two hypervascular tumors in segment 6. The patients liver function was poor, with the indocyanine green retention at 15 min of 49.5%, a total serum bilirubin concentration of 2.0 mg/dl, an albumin concentration of 2.8 g/dl, and an hyaluronic acid concentration of 649 ng/ml. The platelet count was 3.0 x 10(4)/microl secondary to hypersplenism. Partial splenic embolization decreased the splenic volume by 50% preoperatively. At 2 months later, the platelet count was 6.0 x 10(4)/microl, and hand-assisted laparoscopic partial hepatectomy was performed uneventfully. The patients postoperative course was unremarkable, and he was discharged on postoperative day 12.

A case of adenoid cystic carcinoma (ACC) of the breast and review of the utility of preoperative imaging diagnose

A case of adenoid cystic carcinoma (ACC) of the breast in a 66-year-old woman is reported herein. ACC accounts for about 0.1% of all breast cancers. Our patient presented with a small, elastic and hard mass, measuring 2.0x2.0 cm, between both outer quadrants of the right breast. Although physical examination, ultrasonography and magnetic resonance (MR) mammography suggested a benign tumor, aspiration biopsy cytology (ABC) was performed twice, and the second ABC specimen was evaluated as suspicious for breast carcinoma. Breast conserving surgery with a level II lymph node dissection was subsequently performed. There was no lymph node metastases and estrogen receptor (ER) status was negative. Light microscopy revealed various growth patterns, with the cells showing biphasic cellularity. According to immunohistochemical analyses, CEA, actin and vimentin were positive, S-100 protein was negative, and the cytokeratin reaction was partially positive. Therefore, ACC of the breast was diagnosed. Although ACC of the breast is a rare neoplasm, it should be considered in the differential diagnosis even if various diagnostic imaging studies suggest a benign tumor of the breast. Awareness of this tumor will help prevent misdiagnosis.

Microsatellite instability and alternative genetic pathway in intrahepatic cholangiocarcinoma

BACKGROUND/AIMS

Intrahepatic cholangiocarcinoma (ICC) arises from intrahepatic bile duct epithelium and is the second most prevalent among primary liver cancers. The aim of this study was to clarify the mechanism of cholangiocarcinogenesis.

METHODS

We studied the incidence of microsatellite instability (MSI) involving eight highly polymorphic microsatellite markers and alternations of the K-ras, p53 and mdm-2 genes in human ICC tissues. Overexpression of mdm-2 oncoprotein was also immunohistochemically studied.

RESULTS

Of all 65 cases examined, K-ras gene mutation was found in three cases (4.6%) at codon 12. Analysis of p53 alterations was performed in 28 cases including 22 frozen samples and mutations were found in three cases (10.7%). Overexpression of mdm-2 protein was observed in 25 (41.7%) out of 60 cases analyzed. In 22 frozen samples, seven (31.8%) cases showed mdm-2 amplification and four (18.2%) cases revealed MSI-positive phenotype. Among the cases analyzed, all the tumors with mdm-2 amplification/overexpression harbored the wild-type p53 gene and all the microsatellite instability-positive cases were from mass-forming (MF) + periductal-infiltrating (PI) subtype.

CONCLUSIONS

These results suggest that mdm-2 plays a role, which might be partially through inhibiting p53 activity, in cholangiocarcinogenesis and that M

Acute cholecystitis caused by a cholesterol polyp

A 39-year-old man hospitalized with upper abdominal pain had been found to have a 3mm polyp in the body of the gallbladder 3 years previously. Laboratory tests on admission showed mild liver dysfunction. Ultrasonography depicted a dilated gallbladder with increased wall thickness; the polyp could no longer be seen. Computed tomography with drip infusion cholangiography again showed a dilated gallbladder, and also stenosis of the distal cystic duct. The resected specimen obtained by laparoscopic cholecystectomy showed disappearance of the polyp from the body of the gallbladder. A cholesterol stone was incarcerated in the cystic duct, representing an impacted detached cholesterol polyp causing acute cholecystitis. Spontaneous detachment of a cholesterol polyp from the gallbladder mucosa, then, can result in acute cholecystitis.