- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
New Derivatization Reagent for Detection of free Thiol-groups in Metabolites and Proteins in Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging
摘要： Several diseases are associated with disturbed redox signaling and altered metabolism of sulfur-containing metabolites and proteins. Importantly, oxidative degradation of fresh-frozen tissues begins within the normal timescale of MALDI MSI sample preparation. As a result, analytical methods that preserve the redox state of the tissue are urgently needed for refined studies of the underlying mechanisms. Nevertheless, no derivatization strategy for free sulfhydryl groups in tissue is known for MALDI MSI. Here, we report the first derivatization reagent, (E)-2-cyano-N-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)-3-(4-hydroxyphenyl)acrylamide (CHC-Mal), for selective detection of free thiols using MALDI MSI. We performed in-situ derivatization of free thiol groups from thiol-containing metabolites such as glutathione and cysteine and reduced proteins such as insulin and imaged their spatial distribution in porcine and mouse xenograft tissue. Derivatization of thiol-containing metabolites with CHC-Mal for MALDI MSI was also possible when using aged tissue in the presence of excess reducing agents. Importantly, CHC-Mal-derivatized low mass-metabolites could be detected without the use of a conventional MALDI matrix.
关键词： redox signaling,sulfur-containing metabolites,MALDI MSI,derivatization reagent,free thiol-groups
更新于2025-09-23 15:21:01
-
Matrix Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI MSI) for Monitoring of Drug Response in Primary Cancer Spheroids
摘要： Matrix Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI MSI) for Monitoring of Drug Response in Primary Cancer Spheroids. Malignant ascites is a fluid, which builds up in the abdomen and contains cancer cells in the form of single cells or multicellular clusters called spheroids. Malignant ascites has been observed in patients suffering from ovarian, cervical, gastric, colorectal, pancreatic, endometrial, or primary liver cancer. The spheroids are believed to play a major role in chemo resistance and metastasis of the cancer. To ease the discomfort of patients, malignant ascites (MA) is often drained from the abdomen using a procedure called paracentesis. MA retrieved via this minimal invasive procedure is a great source for cancer spheroids, which can be used for testing chemotherapeutic drugs and drug combinations. Herein, the existing workflow is adapted to make concurrent monitoring of drug accumulation, drug response, and drug metabolites feasible using primary spheroids or spheroids grown without a scaffolding matrix. To achieve this, those spheroids are embedded in matrigel, before fixing them with formalin. This makes it possible to process, store, and ship samples at room temperature. This new approach might be used to choose the best targeted therapy for each patient and thereby facilitate personalized medicine.
关键词： cancer spheroids,FFPE,MALDI MSI
更新于2025-09-19 17:13:59
-
Egg white as a quality control in matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI).
摘要： The strength of MALDI-MSI is to analyse and visualize spatial intensities of molecular features from an intact tissue. The distribution of the intensities can then be visualized within a single tissue section or compared in between sections, acquired consecutively. This method can be reliably used to reveal physiological structures and has the potential to identify molecular details, which correlate with biological outcomes. MALDI-MSI implementation in clinical laboratories requires the ability to ensure method quality and validation to meet diagnostic expectations. To be able to get consistent qualitative and quantitative results, standardized sample preparation and data acquisition are of highest priority. We have previously shown that the deposition of internal standards onto the tissue section during sample preparation can be used to improve mass accuracy of monitored m/z features across the sample. Here, we present the use of external and internal controls for the quality check of sample preparation and data acquisition, which is particularly relevant when either many spectra are acquired during a single MALDI-MSI experiment or data from independent experiments are processed together. To monitor detector performance and sample preparation, we use egg white as an external control for peptide and N-glycan MALDI-MSI throughout the experiment. We have also identified endogenous peptides from cytoskeletal proteins, which can be reliably monitored in gynecological tissue samples. Lastly, we summarize our standard quality control workflow designed to produce reliable and comparable MALDI-MSI data from single sections and tissue microarrays (TMAs).
关键词： egg white,MALDI-MSI,quality control,N-glycan,peptide,tissue microarrays,FFPE tissue
更新于2025-09-11 14:15:04
-
Targeted Feature Extraction in MALDI Mass Spectrometry Imaging to Discriminate Proteomic Profiles of Breast and Ovarian Cancer
摘要： Purpose: To develop a mass spectrometry imaging (MSI) based workflow for extracting m/z values related to putative protein biomarkers and using these for reliable tumor classification. Experimental design: Given a list of putative breast and ovarian cancer biomarker proteins, we extracted a set of related m/z values from heterogeneous MSI datasets derived from formalin-fixed paraffin-embedded tissue material. Based on these features, a linear discriminant analysis classification model was trained to discriminate the two tumor types. Results: We show that the discriminative power of classification models based on the extracted features is increased compared to the automatic training approach, especially when classifiers are applied to spectral data acquired under different conditions (instrument, preparation, laboratory). Conclusions and clinical relevance: We obtained robust classification models not confounded by technical variation between MSI measurements. This supports the assumption that the classification of the respective tumor types is based on biological rather than technical differences, and that the selected features are related to the proteomic profiles of the tumor types under consideration.
关键词： feature extraction,tumor typing,MALDI MSI,tissue classification,biomarker proteins
更新于2025-09-09 09:28:46