TY - JOUR A1 - Moraleja, I. A1 - Esteban-Fernández, Diego A1 - Lázaro, A. A1 - Humanes, B. A1 - Neumann, B. A1 - Tejedor, A. A1 - Mena, M. A1 - Jakubowski, Norbert A1 - Gómez-Gómez, M. T1 - Printing metal-spiked inks for LA-ICP-MS bioimaging internal standardization: comparison of the different nephrotoxic behavior of cisplatin, carboplatin, and oxaliplatin JF - Analytical and Bioanalytical Chemistry - Springer N2 - The study of the distribution of the cytostatic drugs cisplatin, carboplatin, and oxaliplatin along the kidney may help to understand their different nephrotoxic behavior. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) allows the acquisition of trace element images in biological tissues. However, results obtained are affected by several variations concerning the sample matrix and instrumental drifts. In this work, an internal standardization method based on printing an Ir-spiked ink onto the surface of the sample has been developed to evaluate the different distributions and accumulation levels of the aforementioned drugs along the kidney of a rat model. A conventional ink-jet printer was used to print fresh sagittal kidney tissue slices of 4 μm. A reproducible and homogenous deposition of the ink along the tissue was observed. The ink was partially absorbed on top of the tissue. Thus, this approach provides a pseudo-internal standardization, due to the fact that the ablation sample and internal standard take place subsequently and not simultaneously. A satisfactory normalization of LA-ICP-MS bioimages and therefore a reliable comparison of the kidney treated with different Pt-based drugs were achieved even for tissues analyzed on different days. Due to the complete ablation of the sample, the transport of the ablated internal standard and tissue to the inductively coupled plasma-mass spectrometry (ICP-MS) is practically taking place at the same time. Pt accumulation in the kidney was observed in accordance to the dosages administered for each drug. Although the accumulation rate of cisplatin and oxaliplatin is high in both cases, their Pt distributions differ. The strong nephrotoxicity observed for cisplatin and the absence of such side effect in the case of oxaliplatin could explain these distribution differences. The homogeneous distribution of oxaliplatin in the cortical and medullar areas could be related with its higher affinity for cellular transporters such as MATE2-k. KW - Bioimaging KW - LA-ICP-MS KW - Cisplatin KW - Standardization KW - Printed internal standard KW - Pt-based drugs KW - Nephrotoxicity PY - 2016 DO - https://doi.org/10.1007/s00216-016-9327-0 SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 9 SP - 2309 EP - 2318 AN - OPUS4-36110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoesl, Simone A1 - Neumann, B. A1 - Techritz, Sandra A1 - Sauter, G. A1 - Simon, R. A1 - Schlüter, H. A1 - Linscheid, M. W. A1 - Theruing, F. A1 - Müller, Larissa A1 - Jakubowski, Norbert T1 - Internal standardization of LA-ICP-MS immunoimaging via printing of universal metal spiked inks onto tissue sections JF - Journal of analytical atomic spectrometry N2 - Formalin-fixed paraffin-embedded (FFPE) specimen from biopsy materials are a widespread sample format for pathologists and medical researchers. Pathologists are archiving vast numbers of FFPE samples which can be stored for decades. Conventional immunohistochemical staining (IHC) of biomarkers on FFPE tissue sections is one of the most important analytical techniques for cancer diagnosis and pathology in general. However standardization for IHC samples and quality management is tedious and differs significantly from clinic to clinic. Combining established IHC staining strategies with modern mass spectrometry mediated methods would increase it`s potential and enable access of large FFPE archives for multiplexed quantitation purposes. In this work element mass spectrometry and a new ink-jet printed internal standardization approach was successfully combined with IHC staining to facilitate quantitative multiplex assays for archived FFPE samples. The printing strategy improves elemental image resolution and reproducibility of paraffin embedded breast cancer tissue sections in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) using conventional IHC staining as a model system to investigate the new capabilities of this technique. For the internal standardization we applied a conventional CD-ink-jet printer to print a metal spiked ink onto the top of thin layer tissue sections with constant density. Printing was carried out in a direct comparison to an iodination of the tissue section as previously described as an alternative standardization method. The use of the printed internal standard allowed correction of the fluctuation during the laser ablation process and compensated instrumental drift effects. Mediated by the ink correction approach we achieved better signal-to-background-ratios (SBR) of 74 and better spatial resolution of 30 µm compared to iodination (SBR=23). This improved performance was demonstrated on tumorous areas in FFPE breast cancer tissue sections and allowing detection of Her-2 in tumorous areas of this tissue with significantly improved contrast. KW - Internal standardization KW - LA-ICP-MS KW - Immuno imaging PY - 2016 DO - https://doi.org/10.1039/c5ja00409h SN - 0267-9477 SN - 1364-5544 VL - 31 IS - 3 SP - 801 EP - 808 AN - OPUS4-35711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hea, Y. A1 - Esteban-Fernandez, Diego A1 - Neumann, B. A1 - Bergmann, U. A1 - Bierkandt, Frank A1 - Linscheid, M. W. T1 - Application of MeCAT-Click labeling for protein abundance characterization of E. coli after heat shock experiments JF - Journal of proteomics N2 - In a proof of concept study, metal-coded affinity tags based on click chemistry (MeCAT-Click) were used to analyze the proteome of Escherichia coli (E. coli) in response to heat stress. This allows high labeling efficiency, high detection sensitivity, and multiplex capabilities, which are pivotal for its application to protein quantification. Two approaches are presented for relative quantification of differentially lanthanide-labeled proteins. The first approach uses isotope-labeling, where ESI-MS was utilized to quantify the differentially labeled proteins from different states of E. coli. With this approach, 14 proteins were found with changed abundance, among them five proteins upregulated. In the second approach, differentially labeled samples were separated by two dimensional gel electrophoresis (2 DE) and scanned by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Comparison of the signal intensities of the different lanthanides was used to quantify different sample states. Based on this information, ESI-MS was used to identify the proteins with different abundance. The sensitivity of LA-ICP-MS allowed us to find one upregulated protein that was nearly invisible by silver staining ("Probable replication endonuclease from retron EC67"). The advantage of this approach is to locate low abundant proteins with differential expression using LA-ICP-MS, which may be overlooked otherwise. Biological significance: This paper demonstrates the successful application of a novel metal labeling strategy to quantify the proteins from complex biological samples. In comparison with former metal labeling strategies, it reduces the steric hindrance and improves the labeling efficiency during the labeling process, which ensure its successful application. This methodology is compatible with both molecular and elemental mass spectrometry. ESI-MS/MS in combination with software-based search allows the identification and relative quantification of labeled proteins. In addition, LA-ICP-MS helps to locate the labeled proteins in 2-DE gels with superior detection capability, thus, target proteins with low abundance can be precisely followed. Its excellent sensitivity allows one to track the proteins of interest that are barely visible by silver staining. KW - Protein quantification KW - Heat shock response KW - Ln-MeCAT-Click labeling KW - nanoLC-ESI-MS/MS KW - 2-D electrophoresis KW - LA-ICP-MS PY - 2016 DO - https://doi.org/10.1016/j.jprot.2015.12.010 SN - 1874-3919 VL - 136 SP - 68 EP - 76 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-35837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -