Browse
Submit Data
Databases
API
Help

Dataset Information

21 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Quantification of EGFR-HER2 Heterodimers in HER2-Overexpressing Breast Cancer Cells Using Liquid-Phase Electron Microscopy.

ABSTRACT: Currently, breast cancer patients are classified uniquely according to the expression level of hormone receptors, and human epidermal growth factor receptor 2 (HER2). This coarse classification is insufficient to capture the phenotypic complexity and heterogeneity of the disease. A methodology was developed for absolute quantification of receptor surface density ρ_R, and molecular interaction (dimerization), as well as the associated heterogeneities, of HER2 and its family member, the epidermal growth factor receptor (EGFR) in the plasma membrane of HER2 overexpressing breast cancer cells. Quantitative, correlative light microscopy (LM) and liquid-phase electron microscopy (LPEM) were combined with quantum dot (QD) labeling. Single-molecule position data of receptors were obtained from scanning transmission electron microscopy (STEM) images of intact cancer cells. Over 280,000 receptor positions were detected and statistically analyzed. An important finding was the subcellular heterogeneity in heterodimer shares with respect to plasma membrane regions with different dynamic properties. Deriving quantitative information about EGFR and HER2 ρ_R, as well as their dimer percentages, and the heterogeneities thereof, in single cancer cells, is potentially relevant for early identification of patients with HER2 overexpressing tumors comprising an enhanced share of EGFR dimers, likely increasing the risk for drug resistance, and thus requiring additional targeted therapeutic strategies.

SUBMITTER: Peckys DB

PROVIDER: S-EPMC8623301 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Liquid-phase electron microscopy of molecular drug response in breast cancer cells reveals irresponsive cell subpopulations related to lack of HER2 homodimers.

Project description:The development of drug resistance in cancer poses a major clinical problem. An example is human epidermal growth factor receptor 2 (HER2) overexpressing breast cancer often treated with anti-HER2 antibody therapies, such as trastuzumab. Since drug resistance is rooted mainly in tumor cell heterogeneity, we examined the drug effect in different subpopulations of SKBR3 breast cancer cells, and compared the results with a drug resistant cell line, HCC1954. Correlative light microscopy and liquid-phase scanning transmission electron microscopy (STEM) were used to quantitatively analyze HER2 responses upon drug binding, whereby many tens of whole cells were imaged. Trastuzumab was found to selectively cross-link and down regulate HER2 homodimers from the plasma membranes of bulk cancer cells. In contrast, HER2 resided mainly as monomers in rare subpopulations of resting- and cancer stem cells (CSCs), and these monomers were not internalized after drug binding. The HER2 distribution was hardly influenced by trastuzumab for the HCC1954 cells. These findings show that resting cells and CSCs are irresponsive to the drug, and thus point towards a molecular explanation behind the origin of drug resistance. This analytical method is broadly applicable to study membrane protein interactions in the intact plasma membrane, while accounting for cell heterogeneity.

| S-EPMC5687022 | biostudies-literature

Phase I study of QLNC120, a novel EGFR and HER2 kinase inhibitor, in pre-treated patients with HER2-overexpressing advanced breast cancer.

Project description:This study evaluated the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), pharmacokinetic profile, and preliminary antitumor activity of QLNC120, an inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2), in HER2 overexpressing advanced breast cancer patients. In addition, the prognostic biomarkers of QLNC120 were investigated. QLNC120 was administered as a single dose, followed by 7 days observation, and then once daily consecutively. Scheduled dose escalation was 450mg, 750mg, 1000mg and 1250mg. For pharmacokinetic analysis, blood samples were collected after the single dose and after the first 7 days of continuous administration. Tissue samples were collected for biomarker analysis. Twenty-four heavily treated HER2 overexpressing advanced breast cancer patients were enrolled. No DLT was observed. MTD was not found. QLNC120 and its active metabolite-lapatinib exposure did not increase in a dose-dependent manner ranging from 450 to 1250mg QLNC120. From 450 to 1250mg QLNC120, the exposure of combination of QLNC120 and its active metabolite-lapatinib was equal to or greater than the exposure of 1250mg lapatinib. Common QLNC120-related toxicities included rash, diarrhea, oral mucositis, hematuria and white blood cell decrease. Seven of twenty-two evaluable patients achieved partial response (PR) or stable disease (SD)≥24 weeks. In biomarker analysis, nine of fifteen patients (60%) had a mutation in HRAS exon 1. Patients with HRAS mutation achieved longer progression free survival(PFS) (24.9 vs 12.9 weeks, p=0.023, HR=0.291). QLNC120 is well-tolerated and safe with encouraging antitumor activity in HER2 overexpressing advanced breast cancer. HRAS mutation was associated with the anti-tumor activity of QLNC120. (Trial registration: NCT01931943, http://ClinicalTrials.gov/show/NCT01931943).

| S-EPMC5482694 | biostudies-literature

Local variations of HER2 dimerization in breast cancer cells discovered by correlative fluorescence and liquid electron microscopy.

Project description:The formation of HER2 homodimers plays an important role in breast cancer aggressiveness and progression; however, little is known about its localization. We have studied the intra- and intercellular variation of HER2 at the single-molecule level in intact SKBR3 breast cancer cells. Whole cells were visualized in hydrated state with correlative fluorescence microscopy and environmental scanning electron microscopy (ESEM). The locations of individual HER2 receptors were detected using an anti-HER2 affibody in combination with a quantum dot (QD), a fluorescent nanoparticle. Fluorescence microscopy revealed considerable differences of HER2 membrane expression between individual cells and between different membrane regions of the same cell (that is, membrane ruffles and flat areas). Subsequent ESEM of the corresponding cellular regions provided images of individually labeled HER2 receptors. The high spatial resolution of 3 nm and the close proximity between the QD and the receptor allowed quantifying the stoichiometry of HER2 complexes, distinguishing between monomers, dimers, and higher-order clusters. Downstream data analysis based on calculating the pair correlation function from receptor positions showed that cellular regions exhibiting membrane ruffles contained a substantial fraction of HER2 in homodimeric state. Larger-order clusters were also present. Membrane areas with homogeneous membrane topography, on the contrary, displayed HER2 in random distribution. Second, HER2 homodimers appeared to be absent from a small subpopulation of cells exhibiting a flat membrane topography, possibly resting cells. Local differences in homodimer presence may point toward functional differences with possible relevance for studying metastasis and drug response.

| S-EPMC4646781 | biostudies-literature

Anti-HER2 immunoliposomes for selective delivery of electron paramagnetic resonance imaging probes to HER2-overexpressing breast tumor cells.

Project description:Electron paramagnetic resonance (EPR) imaging is an emerging modality that can detect and localize paramagnetic molecular probes (so-called spin probes) in vivo. We previously demonstrated that nitroxide spin probes can be encapsulated in liposomes at concentrations exceeding 100 mM, at which nitroxides exhibit a concentration-dependent quenching of their EPR signal that is analogous to the self-quenching of fluorescent molecules. Therefore, intact liposomes encapsulating high concentrations of nitroxides exhibit greatly attenuated EPR spectral signals, and endocytosis of such liposomes represents a cell-activated contrast-generating mechanism. After endocytosis, the encapsulated nitroxide is liberated and becomes greatly diluted in the intracellular milieu. This dequenches the nitroxides to generate a robust intracellular EPR signal. It is therefore possible to deliver a high concentration of nitroxides to cells while minimizing background signal from unendocytosed liposomes. We report here that intracellular EPR signal can be selectively generated in a specific cell type by exploiting its expression of Human Epidermal Growth Factor Receptor 2 (HER2). When targeted by anti-HER2 immunoliposomes encapsulating quenched nitroxides, Hc7 cells, which are novel HER2-overexpressing cells derived from the MCF7 breast tumor cell line, endocytose the liposomes copiously, in contrast to the parent MCF7 cells or control CV1 cells, which do not express HER2. HER2-dependent liposomal delivery enables Hc7 cells to accumulate 750 ?M nitroxide intracellularly. Through the use of phantom models, we verify that this concentration of nitroxides is more than sufficient for EPR imaging, thus laying the foundation for using EPR imaging to visualize HER2-overexpressing Hc7 tumors in animals.

| S-EPMC4041539 | biostudies-literature

Spatial Transcriptomics correlated Electron Microscopy

Project description:This SuperSeries is composed of the SubSeries listed below.

2023-06-21 | GSE202638 | GEO

Accessing local electron-beam induced temperature changes during <i>in situ</i> liquid-phase transmission electron microscopy.

Project description:A significant electron-beam induced heating effect is demonstrated for liquid-phase transmission electron microscopy at low electron flux densities using Au nanoparticles as local nanothermometers. The obtained results are in agreement with theoretical considerations. Furthermore, the impact of beam-induced heating on radiolysis chemistry is estimated and the consequences of the effect are discussed.

| S-EPMC9419575 | biostudies-literature

Coalescence dynamics of platinum group metal nanoparticles revealed by liquid-phase transmission electron microscopy.

Project description:Coalescence, one of the major pathways observed in the growth of nanoparticles, affects the structural diversity of the synthesized nanoparticles in terms of sizes, shapes, and grain boundaries. As coalescence events occur transiently during the growth of nanoparticles and are associated with the interaction between nanoparticles, mechanistic understanding is challenging. The ideal platform to study coalescence events may require real-time tracking of nanoparticle growth trajectories with quantitative analysis for coalescence events. Herein, we track nanoparticle growth trajectories using liquid-cell transmission electron microscopy (LTEM) to investigate the role of coalescence in nanoparticle formation and their morphologies. By evaluating multiple coalescence events for different platinum group metals, we reveal that the surface energy and ligand binding energy determines the rate of the reshaping process and the resulting final morphology of coalesced nanoparticles. The coalescence mechanism, based on direct LTEM observation explains the structures of noble metal nanoparticles that emerge in colloidal synthesis.

| S-EPMC9307684 | biostudies-literature

Dipeptide Nanostructure Assembly and Dynamics <i>via in Situ</i> Liquid-Phase Electron Microscopy.

Project description:In this paper, we report the in situ growth of FF nanotubes examined via liquid-cell transmission electron microscopy (LCTEM). This direct, high spatial, and temporal resolution imaging approach allowed us to observe the growth of peptide-based nanofibrillar structures through directional elongation. Furthermore, the radial growth profile of FF nanotubes through the addition of monomers perpendicular to the tube axis has been observed in real-time with sufficient resolution to directly observe the increase in diameter. Our study demonstrates that the kinetics, dynamics, structure formation, and assembly mechanism of these supramolecular assemblies can be directly monitored using LCTEM. The performance of the peptides and the assemblies they form can be verified and evaluated using post-mortem techniques including time-of-flight secondary ion mass spectrometry (ToF-SIMS).

| S-EPMC9836046 | biostudies-literature

Phase I open-label study of afatinib plus vinorelbine in patients with solid tumours overexpressing EGFR and/or HER2.

Project description:BACKGROUND:This phase Ib study evaluated afatinib plus vinorelbine in patients with advanced solid tumours overexpressing epidermal growth factor receptor (EGFR) and/or human EGFR 2 (HER2). METHODS:Maximum tolerated doses (MTDs) were determined for afatinib (20, 40 or 50?mg, once daily) combined with standard intravenous vinorelbine (part A; 25?mg?m-2 per week) or oral vinorelbine (part B; 60?mg?m-2 per week, increased to 80?mg?m-2 per week at week 3). Secondary end points for expanded MTD cohorts included assessments of safety, pharmacokinetics, tumour response and progression-free survival (PFS). RESULTS:The afatinib MTD was 40?mg with intravenous (MTDA) and oral (MTDB) vinorelbine. The most frequent cycle 1 dose-limiting toxicities were febrile neutropenia and diarrhoea, consistent with individual safety profiles of vinorelbine and afatinib. Common treatment-related adverse events included: diarrhoea (92.7%), asthenia (76.4%), nausea (63.6%), neutropenia (56.4%) and vomiting (54.5%). No notable pharmacokinetic interactions were observed. Best overall tumour response was stable disease in part A (16 out of 28 patients), and partial response in part B (3 out of 27 patients). Median PFS was 14.6 and 15.9 weeks for patients treated at the MTDA and MTDB, including dose-escalation and expansion cohorts. CONCLUSIONS:Afatinib in combination with intravenous or oral vinorelbine demonstrated a manageable safety profile and antitumour activity at the MTD of 40?mg per day.

| S-EPMC5808039 | biostudies-literature

Spatial Transcriptomics correlated Electron Microscopy [MERFISH]

Project description:Current spatial transcriptomics methods provide molecular and spatial information but no morphological readout. Here, we present STEM - a method that correlates multiplexed error-robust FISH with electron microscopy from neighboring tissue sections of the same sample. STEM links transcriptional and spatial organization of single cells with ultrastructural morphology of the tissue in vivo. Using STEM to characterize demyelinated white-matter lesions allowed us to link morphology of myelin-laden foamy microglia to transcriptional signature. Moreover, we revealed that interferon-response microglia have unique morphology and are enriched near CD8 T-cells.

2023-06-21 | GSE202623 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data