ORCID Profile
0000-0002-0798-831X
Current Organisation
Sheffield Hallam University
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Publisher: Wiley
Date: 05-2009
Abstract: The identification of proteins involved in tumour progression or which permit enhanced or novel therapeutic targeting is essential for cancer research. Direct MALDI analysis of tissue sections is rapidly demonstrating its potential for protein imaging and profiling in the investigation of a range of disease states including cancer. MALDI-mass spectrometry imaging (MALDI-MSI) has been used here for direct visualisation and in situ characterisation of proteins in breast tumour tissue section s les. Frozen MCF7 breast tumour xenograft and human formalin-fixed paraffin-embedded breast cancer tissue sections were used. An improved protocol for on-tissue trypsin digestion is described incorporating the use of a detergent, which increases the yield of tryptic peptides for both fresh frozen and formalin-fixed paraffin-embedded tumour tissue sections. A novel approach combining MALDI-MSI and ion mobility separation MALDI-tandem mass spectrometry imaging for improving the detection of low-abundance proteins that are difficult to detect by direct MALDI-MSI analysis is described. In situ protein identification was carried out directly from the tissue section by MALDI-MSI. Numerous protein signals were detected and some proteins including histone H3, H4 and Grp75 that were abundant in the tumour region were identified.
Publisher: American Chemical Society (ACS)
Date: 16-09-2009
DOI: 10.1021/PR900522M
Abstract: MALDI-mass spectrometry imaging (MALDI-MSI) is a technique that allows proteomic information, that is, the spatial distribution and identification of proteins, to be obtained directly from tissue sections. The use of in situ enzymatic digestion as a s le pretreatment prior to MALDI-MSI analysis has been found to be useful for retrieving protein identification directly from formalin-fixed, paraffin-embedded (ffpe) tissue sections. Here, an improved method for the study of the distribution and the identification of peptides obtained after in situ digestion of fppe pancreatic tumor tissue sections by using MALDI-mass spectrometry imaging coupled with ion mobility separation (IMS) is described. MALDI-IMS-MS images of peptide obtained from pancreatic tumor tissue sections allowed the localization of tumor regions within the tissue section, while minimizing the peak interferences which were observed with conventional MALDI-TOF MSI. The use of ion mobility separation coupled with MALDI-MSI improved the selectivity and specificity of the method and, hence, enabled both the localization and in situ identification of glucose regulated protein 78 kDa (Grp78), a tumor biomarker, within pancreatic tumor tissue sections. These findings were validated using immunohistochemical staining.
Publisher: Wiley
Date: 10-2013
DOI: 10.1002/RCM.6693
Abstract: Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) provides a methodology to map the distribution of peptides generated by in situ tryptic digestion of biological tissue. It is challenging to correlate these peptides to the proteins from which they arise because of the many potentially overlapping and hence interfering peptide signals generated. A recombinant protein has been synthesised that when cleaved with trypsin yields a range of peptide standards for use as identification and quantification markers for multiple proteins in one MALDI-IMS-MSI experiment. Mass spectrometry images of the distribution of proteins in fresh frozen and formalin-fixed paraffin-embedded tissue s les following in situ tryptic digestion were generated by isolating signals on the basis of their m/z value and ion mobility drift time, which were correlated to matching peptides in the recombinant standard. Tryptic digestion of the IMS-TAG protein and MALDI-MS analysis yielded m/z values and ion mobility drift time for the signature peptides included in it. MALDI-IMS-MSI images for the distribution of the proteins HSP90 and vimentin, in FFPE EMT6 mouse tumours, and HSP90 and plectin in a fresh frozen mouse fibrosarcoma, were generated by extracting ion images at the corresponding m/z value and drift time from the tissue s les. The IMS-TAG approach provides a new means to confirm the identity of peptides generated by in situ digestion of biological tissue.
Publisher: Springer Science and Business Media LLC
Date: 04-03-2010
DOI: 10.1007/S00216-010-3554-6
Abstract: The development of tissue micro-array (TMA) technologies provides insights into high-throughput analysis of proteomics patterns from a large number of archived tumour s les. In the work reported here, matrix-assisted laser desorption/ionisation-ion mobility separation-mass spectrometry (MALDI-IMS-MS) profiling and imaging methodology has been used to visualise the distribution of several peptides and identify them directly from TMA sections after on-tissue tryptic digestion. A novel approach that combines MALDI-IMS-MSI and principal component analysis-discriminant analysis (PCA-DA) is described, which has the aim of generating tumour classification models based on protein profile patterns. The molecular classification models obtained by PCA-DA have been validated by applying the same statistical analysis to other tissue cores and patient s les. The ability to correlate proteomic information obtained from s les with known and/or unknown clinical outcome by statistical analysis is of great importance, since it may lead to a better understanding of tumour progression and aggressiveness and hence improve diagnosis, prognosis as well as therapeutic treatments. The selectivity, robustness and current limitations of the methodology are discussed.
Publisher: American Chemical Society (ACS)
Date: 11-10-2008
DOI: 10.1021/AC8015467
Abstract: During early-stage drug development, drug and metabolite distribution studies are carried out in animal tissues using a range of techniques, particularly whole body autoradiography (WBA). While widely employed, WBA has a number of limitations, including the following: expensive synthesis of radiolabeled drugs and analyte specificity and identification. WBA only images the radiolabel. MALDI MSI has been shown previously to be advantageous for imaging the distribution of a range of drugs and metabolites in whole body sections. Ion mobility separation (IMS) adds a further separation step to imaging experiments demonstrated here is MALDI-IMS-MS whole body imaging of rats dosed at 6 mg/kg i.v. with an anticancer drug, vinblastine and shown is the distribution of the precursor ion m/z 811.4 and several product ions including m/z 793, 751, 733, 719, 691, 649, 524, and 355. The distribution of vinblastine within the ventricles of the brain is also depicted. Clearly demonstrated in these data are the removal of interfering isobaric ions within the images of m/z 811.4 and also of the transition m/z 811-751, resulting in a higher confidence in the imaging data. Within this work, IMS has shown to be advantageous in both MS and MS/MS imaging experiments by separating vinblastine from an endogenous isobaric lipid.
Publisher: American Chemical Society (ACS)
Date: 29-07-2020
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Malcolm Clench.