Identification of Early Intestinal Neoplasia Protein Biomarkers Using Laser Capture Microdissection and MALDI MS

Abstract

Obtaining protein profiles from a homogeneous cell population in tissues can significantly improve our capability in protein biomarker discovery. In this study, unique protein profiles from the top and bottom sections of mouse crypts and Apc Min؉/؊ adenomas were obtained using laser capture microdissection (LCM) combined with MALDI MS. Statistically significant protein peaks with differential expression were selected, and a set of novel protein biomarkers were identified. Immunohistochemistry was performed to confirm the differentially expressed protein biomarkers found by LCM combined with MALDI MS. To validate the relevance of the findings in human colorectal cancer (CRC), S100A8 was further confirmed in human CRC using immunohistochemistry. In addition, S100A8 was found to have an increased expression at different human CRC stages (Duke's A-D) compared with controls at both protein (n ‫؍‬ 168 cases) and RNA (n ‫؍‬ 215 cases) levels. Overall LCM combined with MALDI MS is a promising method to identify intestinal protein biomarkers from minute amounts of tissue. The novel protein biomarkers identified from the top and bottom crypts will increase our knowledge of the specific protein changes taking place during cell migration from the crypt bottom to top. In addition, the identified cancer protein biomarkers will aid in the exploration of colorectal tumorigenesis mechanisms as well as in the advancement of molecularly based diagnosis of colorectal cancer. Molecular & Cellular Proteomics 8:936 -945, 2009.

MALDI imaging mass spectrometry of human tissue: method challenges and clinical perspectives

“…We have previously shown feasibility of the histology directed protein profiling for breast [29,30], lung [31], colon [32], brain [33,34], gastric [35] cancers, as well as other diseases, such as inflammatory bowel diseases [36]. Several reports have involved studies to predict response to neoadjuvant chemotherapy and radiation [17] as well as HER2 status in breast cancer [37], molecular diagnosis of prostate cancer [3,38], classification [6] and survival prediction [39] in lung cancer, and determination of molecular tumor margins [40,41].…”

A Quantitative Proteomic Approach of the Different Stages of Colorectal Cancer Establishes OLFM4 as a New Nonmetastatic Tumor Marker

“…Tumor analysis is challenging, given the heterogeneity of the colorectal cancer tissue and the limited number of tumor cells generally available. To increase the specificity of the analysis, tumor cells should be ideally isolated from heterogeneous samples by laser capture microdissection (LCM) (29). Although this approach is widely used in the genomic field, proteomic analyses of tumor tissue are limited, and to our knowledge only one study has been performed in CRC, using adenoma tissue (29).…”

An Introduction to Proteomics Technologies for the Genomics Scientist

“…see Ref. [65]), although this will vary depending on the experiment. The major limitation of MALDI imaging is that only those proteins that are soluble under matrix application conditions that retain the in vivo spatial protein distribution are analyzed.…”

“…see Ref. [65]); and when coupled with unsupervised multivariate statistical clustering algorithms, the patterns produced by MALDI-IMS can provide robust prognostic and diagnostic disease markers [51,52] even though a fraction of the proteome is covered. DIGE technology can similarly produce quantitative data from large cohorts [23].…”