Targeting Her2-insYVMA with Covalent Inhibitors-A Focused Compound Screening and Structure-Based Design Approach.

Mutated or amplified Her2 serves as a driver of non-small cell lung cancer or mediates resistance toward the inhibition of its family member epidermal growth factor receptor with small-molecule inhibitors. To date, small-molecule inhibitors targeting Her2 which can be used in clinical routine are lacking, and therefore, the development of novel inhibitors was undertaken. In this study, the well-established pyrrolopyrimidine scaffold was modified with structural motifs identified from a screening campaign with more than 1600 compounds, which were applied against wild-type Her2 and its mutant variant Her2-A775_G776insYVMA. The resulting inhibitors were designed to covalently target a reactive cysteine in the binding site of Her2 and were further optimized by means of structure-based drug design utilizing a set of obtained complex crystal structures. In addition, the analysis of binding kinetics and absorption, distribution, metabolism, and excretion parameters as well as mass spectrometry experiments and western blot analysis substantiated our approach.

Application of proteometric approach for identification of functional mutant sites to improve the binding affinity of anticancer biologic trastuzumab with its antigen human epidermal growth factor receptor 2.

The aim of the present study was to develop a linear regression model aiding to a quick scan of the most important sites for mutation of an anticancer biologic trastuzumab. The important sites identified on trastuzumab can be used to carry out site-directed mutagenesis to improve the binding affinity of the drug towards its antigen, human epidermal growth factor receptor 2 (HER2). This will lead to low dosage requirement of the drug for treating cancer patients, which in turn help to cut the cost and combat development of resistance. A quantitative structure-activity relationship (QSAR) model was built by multiple linear regressions using genetic algorithm-based feature selection (GA-MLR) method using 48 dependent variables (dissociation constant Kd ) and 226 independent variables (theoretical descriptors generated using a proteometrics approach). The final QSAR model selected in the study was more on the basis of ability to predict accurately independent test data and generalization ability of the model rather than mere statistical significance of the model. With combined analysis of descriptors presented in final QSAR model and most frequent descriptors pooled from all solution models, it was demonstrated that the modeling procedure was able to bring on the factors important for antigen-antibody interactions with an example of HER2-trastuzumab interaction reported in previous experimental studies. This paper will allow the prediction of the most preferable site to mutate for improving the binding affinity of trastuzumab with HER2 and also will be helpful in selecting most preferable amino acids to substitute in the selected site for mutations. This is the novel report on proteometrics approach with autocorrelation formalism for antibody engineering, which can be extended to other antibody-antigen pairs.

FeSe quantum dots for in vivo multiphoton biomedical imaging.

An immense demand in biomedical imaging is to develop efficient photoluminescent probes with high biocompatibility and quantum yield, as well as multiphoton absorption performance to improve penetration depth and spatial resolution. Here, iron selenide (FeSe) quantum dots (QDs) are reported to meet these criteria. The synthesized QDs exhibit two- and three-photon excitation property at 800- and 1080-nm wavelengths and high quantum yield (ca. 40%), which are suitable for second-window imaging. To verify their biosuitability, poly(ethylene glycol)-conjugated QDs were linked with human epidermal growth factor receptor 2 (HER2) antibodies for in vitro/in vivo two-photon imaging in HER2-overexpressed MCF7 cells and a xenograft breast tumor model in mice. Imaging was successfully carried out at a depth of up to 500 µm from the skin using a nonlinear femtosecond laser at an excitation wavelength of 800 nm. These findings may open up a way to apply biocompatible FeSe QDs to multiphoton cancer imaging.

Expression, purification, and characterization of the native intracellular domain of human epidermal growth factor receptors 1 and 2 in Escherichia coli.

Human epidermal growth factor receptors (EGFR) are an important target in drug discovery in terms of both protein-small-molecule interactions and protein-protein interactions. In this work, the isolation of a stable soluble protein of the tyrosine kinase domain of EGFR in Escherichia coli expression has been accomplished. This successful study presents the expression and purification conditions to obtain a stable soluble protein of the active tyrosine kinase domain of EGFR (EGFR-TK) and ErbB2 (ErbB2-TK) in a bacterial system, albeit in relatively low yields. The recombinant gene was inserted into a pColdI vector and recombinant protein was expressed at low temperature. Purification of EGFR-TK and ErbB2-TK took place under the same conditions by purified supernatant using a diethylaminoethyl sepharose column followed by anion exchange and size-exclusion chromatography columns. The final yields of purified EGFR-TK and ErbB2-TK were 8.4 and 9.5 mg per liter of culture, respectively. Determination of EGFR-TK and ErbB2-TK was performed via enzyme activity with commercial drugs. The IC50 values of erlotinib and afatinib against EGFR-TK were 13.09 nM and 2.36 nM respectively, while the IC50 values of lapatinib and afatinib against ErbB2-TK were 24.69 nM and 1.36 nM, respectively. These results confirmed that soluble proteins of the active intracellular domain of the HERs family were successfully expressed and purified in a bacterial system. The new protein expression and purification protocol will greatly facilitate the enzymatic inhibition and structural studies of this protein for drug discovery.

Clinicopathologic Characteristics of HER2-positive Metastatic Colorectal Cancer and Detection of HER2 in Plasma Circulating Tumor DNA.

BACKGROUND: Therapy targeting human epidermal growth factor receptor 2 (HER2, also known as ERBB2) is an effective approach for HER2-positive metastatic colorectal cancer (mCRC). HER2 status is typically determined using immunohistochemistry and fluorescence in situ hybridization. Circulating tumor DNA (ctDNA) enables noninvasive detection of gene mutations and copy number alterations including HER2 amplification. MATERIALS AND METHODS: We screened 351 patients with mCRC and studied the clinicopathologic characteristics of HER2-positive mCRC. HER2 expression in tumor samples measured with immunohistochemistry and fluorescence in situ hybridization was compared with HER2 copy number variation in plasma ctDNA detected by targeted sequence capture covering exons of 170 genes. We also examined the correlation between changes in tumor burden in ctDNA and antitumor response by imaging evaluation during the treatment course. RESULTS: Positive HER2 status was observed in 12 (3.4%) patients (7 males and 5 females), with a median age of 56 years. The HER2 concordance rate between tumor samples and ctDNA was 66.7% (20/30). Changes in tumor burden in ctDNA during the treatment course correlated with responses on imaging. CONCLUSIONS: Detection of HER2 copy number variation in ctDNA may be an alternative option for noninvasive determination of HER2 status. Tumor burden changes in ctDNA were consistent with imaging evaluation.

FISH and HER2/neu equivocal immunohistochemistry in breast carcinoma.

AIM: The aim of this study was to validate the role of fluorescence in situ hybridization (FISH) in investigating HER2/neu gene amplification (human epidermal growth factor receptor 2) in patients with HER2/neu equivocal breast cancer diagnosed on immunohistochemistry (IHC). MATERIALS AND METHODS: This was a retrospective study conducted from January 2013 to October 2017. A total of 134 patients diagnosed with invasive breast carcinoma and HER2/neu equivocal status on IHC were analyzed. Also, the cases for the years 2016 and 2017 formed a subgroup that was analyzed further to study the impact of pre-analytical factors on IHC and FISH results. RESULTS: A total of 134 women with HER2/neu IHC equivocal breast cancer were included in the study with a median age of 50 years (range 25-81). HER2/neu amplification by FISH was noted in 72 (54%) cases, whereas it was non-amplified in 52 (39%) cases. Ten cases were reported as equivocal even on FISH (ASCO/CAP 2013 guidelines). Polysomy 17 was noted in 55 cases (41%), of which 26 patients were≤50 years and 29 patients were >50 years of age. Twenty (36%) of these 55 cases showed HER2/neu amplification, whereas 26 (48%) cases were non-amplified and 9 (16%) cases were reported as equivocal on FISH. Also, more than half of the polysomy cases were hormone receptor negative. CONCLUSION: IHC is a good screening tool for negative and positive results. Any patient targeted for trastuzumab therapy should undergo confirmation of HER2/neu equivocal status by FISH analysis. We also suggest that if a non-classical FISH pattern is seen, the test should be repeated with a non-centromeric chromosome 17 reference locus probe for better treatment planning.

Dual signal amplification photoelectrochemical biosensor for highly sensitive human epidermal growth factor receptor-2 detection.

Photoelectrochemical (PEC) biosensor for highly sensitive detection of breast cancer biomarker human epidermal growth factor receptor-2 (HER2) is reported utilizing a dual signal amplification strategy. The biosensor was prepared based on tungsten sulfide nanowire array on Ti mesh (WS2 NW/TM). Such WS2 NW/TM electrode can generate photoelectric signal under visible light excitation. The HER2 aptamer was wrapped onto the nanowire array surface for specific binding with HER2 molecules, and gold nanoparticles (Au NPs) that modified with glucose oxidase (GOx) and HER2 binding peptide was utilized for signal amplification. The H2O2 that generated by GOx catalyzed glucose reaction and localized surface plasmon resonance of Au NPs can both enhance the PEC current intensity of the biosensor, leading to dual signal amplification. The PEC current intensity is enhanced linearly with HER2 concentration in the 0.5-10 ng/mL range with limit of detection of 0.36 ng/mL. Such biosensor was applied for the detection of HER2 in breast cancer serum samples with detection results in good agreement with commercial ELISA results.

Reducing the Detrimental Effects of Saturation Phenomena in FRET Microscopy.

Although Förster resonance energy transfer (FRET) is one of the most widely used biophysical methods in biology, the effect of high excitation intensity, leading to donor and acceptor saturation, has not been addressed previously. Here, we present a formalism for the experimental determination of the FRET efficiency at high excitation intensity when saturation of both the donor and the acceptor significantly affect conventional FRET calculations. We show that the proposed methodology significantly reduces the dependence of the FRET efficiency on excitation intensity, which otherwise significantly distorts FRET calculations at high excitation intensities commonly used in experiments. The work presented here adds additional rigor to the FRET-based investigation of protein interactions and strengthens the device independence of such results.

Abnormal Anionic Porphyrin Sensing Effect for HER2 Gene Related DNA Detection via Impedance Difference between MWCNTs and Single-Stranded DNA or Double-Stranded DNA.

Human epidermal growth factor receptor 2 (HER2) is a key tumor marker for several common and deadly cancers. It is of great importance to develop efficient detection methods for its over-expression. In this work, an electrochemical impedance spectroscopy (EIS) method adjustable by anionic porphyrin for HER2 gene detection has been proposed, based on the impedance difference between multi-walled carbon nanotubes (MWCNTs) and DNA. The interesting finding herein is that with the addition of anionic porphyrin, i.e., meso-tetra(4-sulfophenyl)-porphyrin (TSPP), the impedance value obtained at a glass carbon electrode (GCE) modified with MWCNTs and a single stranded DNA (ssDNA), the probe DNA that might be assembled tightly onto MWCNTs through π-π stacking interaction, gets a slight decrease; however, the impedance value from a GCE modified with MWCNTs and a double stranded DNA (dsDNA), the hybrid of the probe DNA with a target DNA, which might be assembled loosely onto MWCNTs for the screening effect of phosphate backbones in dsDNA, gets an obvious decrease. The reason may be that on the one hand, being rich in negative sulfonate groups, TSPP will try to push DNA far away from CNTs surface due to its strong electrostatic repulsion towards DNA; on the other hand, rich in planar phenyl or pyrrole rings, TSPP will compete with DNA for the surface of CNTs since it can also be assembled onto CNTs through conjugative interactions. In this way, the "loosely assembled" dsDNA will be repelled by this anionic porphyrin and released off CNTs surface much more than the "tightly assembled" ssDNA, leading to a bigger difference in the impedance value between dsDNA and ssDNA. Thus, through the amplification effect of TSPP on the impedance difference, the perfectly matched target DNA could be easily determined by EIS without any label. Under the optimized experimental conditions, this electrochemical sensor shows an excellent linear response to target DNA in a concentration range of 2.0 × 10-11⁻2.0 × 10-6 M with a limit of detection (LOD) of 6.34 × 10-11 M (S/N = 3). This abnormally sensitive electrochemical sensing performance resulting from anionic porphyrin for DNA sequences specific to HER2 gene will offer considerable promise for tumor diagnosis and treatment.

Safety of everolimus plus exemestane in patients with hormone-receptor-positive, HER2-negative locally advanced or metastatic breast cancer: results of phase IIIb BALLET trial in Spain

Background: Everolimus with exemestane has shown promising activity in patients with hormone-receptor (HR)-positive HER2-negative endocrine-resistant advanced breast cancer. It is necessary, therefore, to characterize the safety profile of this new combination in the real-world clinical setting and in the broadest possible population. Patients and methods: Post-menopausal women with HR-positive HER2-negative advanced breast cancer progressing after prior non-steroidal aromatase inhibitors (NSAIs) were included. The objectives of this analysis were to evaluate the safety profile of this combination in a subset of Spanish patients in the BALLET trial and to characterize grade 3 and 4 adverse events (AEs) in routine clinical practice in Spain. Results: Between September 2012 and July 2013, 429 patients (20% of the overall study population) were included in the BALLET study in 52 hospitals in Spain, of whom 100 (23%) were ≥ 70 years. The median treatment duration was 3.14 and 3.03 months for exemestane and everolimus, respectively. The most common reasons for discontinuation of treatment were local reimbursement of everolimus (43%), followed by disease progression (31%) and the incidence of AEs (15%). The most frequent AEs causing permanent discontinuation were pneumonitis (4%), asthenia (2%) and stomatitis (2%). Overall, 87% of patients experienced at least one AE of any grade, 30% of patients at least one grade 3 AE and 2% of patients a grade 4 AE. Conclusion: The safety profile in Spanish patients of the BALLET trial is consistent with the results obtained in the overall population of the trial, as well as in previous clinical trials

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Ultrasensitive direct impedimetric immunosensor for detection of serum HER2.

Assesment of human epidermal growth factor receptor 2 status is a key factor prompting definitive treatment decisions that help in reducing mortality rates associated with breast cancer. In this article, highly sensitive and low-cost impedimetric immunosensor using single-chain fragment variable antibody fragments was developed for quantitative detection of human epidermal growth factor receptor 2 from serum employing gold nanoparticle-modified disposable screen-printed carbon electrodes. The gold nanoparticles facilitate fast electron transfer and offer a biocompatible surface for immobilization of small antibody fragments in an oriented manner, resulting in improved antigen binding efficiency. The single-chain fragment variable antibody fragment-modified screen printed immunosensor exhibits wide dynamic range of 0.01-100 ng mL-1 and detection limit of 0.01 ng mL-1. The advantages offered by this platform in terms of high sensitivity, broad dynamic range and low-cost demonstrates great potential for improved monitoring of human epidermal growth factor receptor 2 levels for the management of breast and other cancers.

Disposable inkjet-printed electrochemical platform for detection of clinically relevant HER-2 breast cancer biomarker.

Rapidly fabricated, disposable sensor platforms hold tremendous promise for point-of-care detection. Here, we present an inexpensive (< $0.25) fully inkjet printed electrochemical sensor with integrated counter, reference, and working electrodes that is easily scalable for commercial fabrication. The electrochemical sensor platform featured an inkjet printed gold working 8-electrode array (WEA) and counter electrode (CE), along with an inkjet -printed silver electrode that was chlorinated with bleach to produce a Ag/AgCl quasi-reference electrode (RE). As proof of concept, the electrochemical sensor was successfully applied for detection of clinically relevant breast cancer biomarker Human Epidermal Growth Factor Receptor 2 (HER-2). Capture antibodies were bound to a chemically modified surface on the WEA and placed into a microfluidic device. A full sandwich immunoassay was constructed following a simultaneous injection of target protein, biotinylated antibody, and polymerized horseradish peroxide labels into the microfluidic device housing the WEA. With an ultra fast assay time, of only 15mins a clinically relevant limit of detection of 12pgmL-1 was achieved. Excellent reproducibility and sensitivity were observed through recovery assays preformed in human serum with recoveries ranging from 76% to 103%. These easily fabricated and scalable electrochemical sensor platforms can be readily adapted for multiplex detection following this rapid assay protocol for cancer diagnostics.

para-Sulfonatocalix[4]arene stabilized gold nanoparticles multilayers interfaced to electrodes through host-guest interaction for sensitive ErbB2 detection.

Nanoparticle (NP) structure, compositing and the nature of the NP-functionalized electrode interface have a strong influence upon electrochemical properties that are critical in applications such as sensing, photocatalysis and electrocatalysis. Existing methods to fabricate NP-functionalized electrodes do not allow or precise control over all these variables, especially the NP-electrode interface, making it difficult to understand and predict how structural changes influence electrode activity and consequently limit the application. To conquer this problem, in this study, we fabricated a stepwise construction of a novel supramolecular stabilized gold nanoparticles (AuNPs) multilayer mediated by guest molecules, yielding 3D AuNPs assembly at the electrode interface. para-Sulfonatocalix[4]arene (pSC4), a water soluble macrocyclic synthetic receptor, has been served as a stabilizing ligand for preparation and gaining new insights into pSC4 stabilized gold nanoparticles (pSC4-AuNPs) tethered on the electrode interface through host-guest interaction. We investigated the electrochemical properties of multilayer pSC4-AuNPs modified gold electrode using different core size of AuNPs with varying layer number. The electron transfer ability was characterized by electrochemical impedance spectroscopy (EIS). Electrochemical signals are significantly enhanced through the layer-by-layer assembly of pSC4-AuNPs due to its high conductivity and high effective area. With this innovative method, by taking the assay of a tumor marker as an example, human epidermal growth factor receptor 2 (ErbB2) was successfully measured with a detection limit of 0.5ng/mL. Taking the advantage of the pSC4-AuNPs multilayer's good biocompatibility, high effective area and high electronic transmission, 3D AuNPs multilayer produced on the electrode interface suggests a portable synthetic pathway for the application into sensitive electrochemical biosensor.

A sandwich-type electrochemical immunosensor based on in situ silver deposition for determination of serum level of HER2 in breast cancer patients.

The sensitive quantification of Human Epidermal growth factor Receptor 2 (HER2), as a key prognostic tumor marker, plays a critical role in screening, early diagnosis and management of breast cancer. This paper describes a sandwich-type immunoassay with silver signal enhancement strategy for highly sensitive detection of HER2. For this purpose, the target capturing step was designed by functionalization of 3-aminopropyltrimethoxysilane coated magnetite nanoparticles with antibody (antiHER2/APTMS-Fe3O4), as a platform bioconjugate (PB), and immobilized at a bare GCE. Then, in the presence of label-free immunosensor, the PB was covered by magnetic gold nanoparticles self-assembled with thiolated antibodies (antiHER2/Hyd@AuNPs-APTMS-Fe3O4) containing chemically reduced silver ions, as a label bioconjugate (LB). Under optimum conditions, a linear relationship between the differential pulse voltammetric (DPV) stripping signal of silver and the logarithm of HER2 concentrations was obtained in the range of 5.0 × 10-4-50.0ngmL-1 (R2 = 0.9906) with a detection limit of 2.0 × 10-5ngmL-1. The effectiveness of this protocol was evaluated experimentally through employing of designed immunosensor for detection of the serum level of tumor marker. The good consistency of the results with those obtained by the enzyme-linked immunosorbent assay (ELISA) conventional method (p-value of < 0.05) showed that this immunosensor can be applied for the testing of HER2 in clinical samples of breast cancer patients.

Human epidermal growth factor receptor 2 amplification detection by droplet digital polymerase chain reaction in formalin-fixed paraffin-embedded breast and gastric cancer samples.

OBJECTIVE: Human epidermal growth factor receptor 2 (HER2) is an important biomarker for the precise individualized treatment including trastuzumab of HER2-positive breast and gastric cancer. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are the routine analyses for formalin-fixed paraffin-embedded (FFPE) samples. However, IHC is variable and depends on the evaluator, and FISH is a labor intensive and expensive method. We evaluated the feasibility of droplet digital polymerase chain reaction (ddPCR) as a precise and quantitative method for HER2 amplification test. MATERIALS AND METHODS: We used ddPCR to confirm HER2 amplification status in 24 breast cancer and 29 gastric cancer samples to validate the HER2 cutoff value in ddPCR. After setting cutoff value, all the above-mentioned samples were tested by IHC. Afterward, another 51 equivocal IHC 2+ gastric cancer samples were further determined by FISH and ddPCR, respectively, and the concordance between ddPCR and FISH was calculated. RESULTS: We set the HER2 cutoff value at 1.8. The concordance rate of HER2 status between ddPCR and IHC was 94.4% (17 out of 18) in 24 breast cancer samples. In 29 gastric cancer specimens, the concordance rate of HER2 amplification between ddPCR and IHC was 100% (22 out of 22). At last, compared with FISH determined HER2 status, ddPCR HER2 scores correctly classified 44 of 51 cases with 86.3% concordance in 51 equivocal IHC 2+ gastric cancer samples. CONCLUSIONS: ddPCR was able to identify HER2 amplification status in breast and gastric cancers with precise correlation with IHC and FISH results. This method might become a standard method for testing FFPE samples. However, the technology requires further research.

Reduced graphene oxide-chitosan-aptamer interface as new platform for ultrasensitive detection of human epidermal growth factor receptor 2.

The present work describes an ultrasensitive electrochemical aptamer-based assay for detection of human epidermal growth factor receptor 2 protein (HER2) cancer biomarker as a model analyte. Results show that the reduced graphene oxide-chitosan (rGO-Chit) film as a suitable electrode material possesses great favorable properties including high homogeneity, good stability, large surface area and high fraction of amine groups as aptamer binding sites. Various steps of aptasensor fabrication were characterized using microscopic, energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared (FTIR) spectroscopy and electrochemical techniques. Using methylene blue (MB) as an electrochemical probe and differential pulse voltammetry (DPV) technique, two linear concentration ranges of 0.5-2ngml-1 and 2-75ngml-1 were obtained with a high sensitivity of 0.14µAng-1ml and a very low detection limit of 0.21ngml-1 (very lower than the clinical cut-off). The fabricated aptasensor showed excellent selectivity for detection of HER2 in complex matrix of human serum samples. The sensitive detection of HER2 can be attributed to the multiple signal amplification of MB during its accumulation to the modified electrode surface via both affinity interaction to aptamer molecules and electrostatic adsorption to the HER2 analyte as well as high charge transfer kinetic properties of the applied rGO-Chit film. The rapid and simple preparation of the proposed aptasensor as well as its high selectivity, stability and reproducibility provided a promising protocol for non-invasive diagnosis for various points of care application. The proposed aptasensor showed excellent analytical performance in comparison with current HER2 biosensors.

Development of a test that measures real-time HER2 signaling function in live breast cancer cell lines and primary cells.

BACKGROUND: Approximately 18-20% of all human breast cancers have overexpressed human epidermal growth factor receptor 2 (HER2). Standard clinical practice is to treat only overexpressed HER2 (HER2+) cancers with targeted anti-HER2 therapies. However, recent analyses of clinical trial data have found evidence that HER2-targeted therapies may benefit a sub-group of breast cancer patients with non-overexpressed HER2. This suggests that measurement of other biological factors associated with HER2 cancer, such as HER2 signaling pathway activity, should be considered as an alternative means of identifying patients eligible for HER2 therapies. METHODS: A new biosensor-based test (CELxTM HSF) that measures HER2 signaling activity in live cells is demonstrated using a set of 19 human HER2+ and HER2- breast cancer reference cell lines and primary cell samples derived from two fresh patient tumor specimens. Pathway signaling is elucidated by use of highly specific agonists and antagonists. The test method relies upon well-established phenotypic, adhesion-related, impedance changes detected by the biosensor. RESULTS: The analytical sensitivity and analyte specificity of this method was demonstrated using ligands with high affinity and specificity for HER1 and HER3. The HER2-driven signaling quantified ranged 50-fold between the lowest and highest cell lines. The HER2+ cell lines were almost equally divided into high and low signaling test result groups, suggesting that little correlation exists between HER2 protein expression and HER2 signaling level. Unexpectedly, the highest HER2-driven signaling level recorded was with a HER2- cell line. CONCLUSIONS: Measurement of HER2 signaling activity in the tumor cells of breast cancer patients is a feasible approach to explore as a biomarker to identify HER2-driven cancers not currently diagnosable with genomic techniques. The wide range of HER2-driven signaling levels measured suggests it may be possible to make a distinction between normal and abnormal levels of activity. Analytical validation studies and clinical trials treating HER2- patients with abnormal HER2-driven signaling would be required to evaluate the analytical and clinical validity of using this functional biomarker as a diagnostic test to select patients for treatment with HER2 targeted therapy. In clinical practice, this method would require patient specimens be delivered to and tested in a central lab.

Detection of Her2-overexpressing cancer cells using keyhole shaped chamber array employing a magnetic droplet-handling system.

An on-chip gene expression analysis compartmentalized in droplets was developed for detection of cancer cells at a single-cell level. The chip consists of a keyhole-shaped reaction chamber with hydrophobic modification employing a magnetic bead-droplet-handling system with a gate for bead separation. Using three kinds of water-based droplets in oil, a droplet with sample cells, a lysis buffer with magnetic beads, and RT-PCR buffer, parallel magnetic manipulation and fusion of droplets were performed using a magnet-handling device containing small external magnet patterns in an array. The actuation with the magnet offers a simple system for droplet manipulation that allows separation and fusion of droplets containing magnetic beads. After reverse transcription and amplification by thermal cycling, fluorescence was obtained for detection of overexpressing genes. For clinical detection of gastric cancer cells in peritoneal washing, the Her2-overexpressing gastric cancer cells spiked within normal cells was detected by gene expression analysis of droplets containing an average of 2.5 cells. Our developed droplet-based cancer detection system manipulated by external magnetic force without pumps or valves offers a simple and flexible set-up for transcriptional detection of cancer cells, and will be greatly advantageous for less-invasive clinical diagnosis and prognostic prediction.

Bimolecular complementation affinity purification (BiCAP) reveals dimer-specific protein interactions for ERBB2 dimers.

The dynamic assembly of multiprotein complexes is a central mechanism of many cell signaling pathways. This process is key to maintaining the spatiotemporal specificity required for an accurate, yet adaptive, response to rapidly changing cellular conditions. We describe a technique for the specific isolation and downstream proteomic characterization of any two interacting proteins, to the exclusion of their individual moieties and competing binding partners. We termed the approach bimolecular complementation affinity purification (BiCAP) because it combines the use of conformation-specific nanobodies with a protein-fragment complementation assay with affinity purification. Using BiCAP, we characterized the specific interactome of the epidermal growth factor receptor (EGFR) family member ERBB2 when in the form of a homodimer or when in the form of a heterodimer with either EGFR or ERBB3. We identified dimer-specific interaction patterns for key adaptor proteins and identified a number of previously unknown interacting partners. Functional analysis for one of these newly identified partners revealed a noncanonical mechanism of extracellular signal-regulated kinase (ERK) activation that is specific to the ERBB2:ERBB3 heterodimer and acts through the adaptor protein FAM59A in breast cancer cells.

The real-world cost-effectiveness of adjuvant trastuzumab in HER-2/neu-positive early breast cancer in Taiwan.

BACKGROUND: Trastuzumab was considered a cost-effective adjuvant treatment for HER 2-positive early breast cancer. Since 2010, the Taiwanese National Health Insurance (NHI) has started to reimburse for 1-year adjuvant treatment. This study aims to provide an updated cost-effectiveness analysis from the NHI perspective, which explores assumptions about long-term cardiac toxicity and treatment benefit of 1-year adjuvant treatment sequentially after chemotherapy. METHODS: A Markov model was used to evaluate the cost-effectiveness of 1-year adjuvant trastuzumab for HER-2/neu positive early breast cancer over a 20-year life-time horizon. A probability sensitivity analysis using Monte Carlo simulation was performed to characterize uncertainties in the expected outcomes, which are expressed as an incremental costs effectiveness ratio (ICER, cost/QALY). A willingness-to-pay threshold of 3-times the per capita gross domestic product was adopted according to the WHO definition. The Taiwan per capita gross domestic product in 2015 was US$22,355; thus, a threshold was considered as NT$2,011,950 (US$67 065, 1USD =30 NTD in 2015). RESULTS: The model showed that adjuvant trastuzumab treatment in HER-2/neu positive early breast cancer yielded 1.631 quality-adjusted life-years (QALY) compared with no trastuzumab treatment. The ICER was US $51,863 per QALY gained in the base-case scenario. The Monte Carlo simulation by varying all variables simultaneously demonstrated that the probability of cost-effectiveness at the willingness-to-pay threshold of US$67,065 was 50% for 1-year adjuvant trastuzumab. CONCLUSIONS: From this real-world study, 1-year adjuvant trastuzumab treatment is likely to be a cost-effective therapy for patients with HER-2 positive breast cancer at the willingness-to-pay threshold of 3-times GDP per capita in Taiwan.