Proteomic Characterization of Colorectal Cancer Tissue from Patients Identifies Novel Putative Protein Biomarkers.

Maja Ludvigsen,Louise Thorlacius-Ussing,Mogens Tornby Stender,Henrik Vorum,Bent Honoré,Ole Thorlacius-Ussing

doi:10.3390/cimb43020074

Abstract

Colorectal cancer (CRC) is one of the leading causes of cancer-related death over the world. There is a great need for biomarkers capable of early detection and as targets for treatment. Differential protein expression was investigated with two-dimensional gel electrophoresis (2D-PAGE) followed by identification with liquid chromatography–tandem mass spectrometry (LC-MS/MS) in CRC patient tissue from (i) the peripheral part of the tumor, (ii) the central part of the tumor as well as from (iii) a non-involved part of the colorectal tissue. The expression patterns of six identified proteins were further evaluated by one-dimensional Western blot (1D-WB) analysis of the CRC tissue. Proteins that were perturbed in expression level in the peripheral or in the central part of the tumor as compared with the non-involved part included S100A11, HNRNPF, HNRNPH1 or HNRNPH2, GSTP1, PKM and FABP1. These identified markers may have future diagnostic potential or may be novel treatment targets after further evaluation in larger patient cohorts.

Highlights

Colorectal cancer (CRC) is one of the leading causes of cancer-related death over the world
The system consisted of a normal derived colon mucosa cell line, NCM460 [4], analyzed against two different colorectal cancer cell lines established from human colonic carcinoma [5,6]
The obvious advantage of such a system is the access to virtually unlimited amounts of homogeneous samples for the initial discovery based proteomic analysis identifying differentially expressed proteins, i.e., putative biomarkers that subsequently can be further analyzed in patient tissue

Summary

Introduction

Colorectal cancer (CRC) is one of the leading causes of cancer-related death over the world. Resected colorectal tumors from patients may possess heterogeneity due to inter and intra biological differences within the tumor from the central parts that may show some degree of necrosis to the peripheral parts that may contain normal cells by being close to the non-involved colorectal tissue. Despite of all these concerns with tissue heterogeneity, we decided to try whether our previously described 2D-PAGE technology [3] in a simplistic approach applied directly to different parts of the tumor with subsequent immunological verification (1D-WB) on the same tissue could bring novel putative markers to attention. Some of the identified proteins observed here have already been investigated as promising while others need further investigation for suitability as biomarkers or drug targets

Tissue Biopsies from Patients with CRC

Western Blotting

Patient Characteristics

Protein Expression Patterns in High TNM Stage versus Low TNM Stage

Immunological Evaluation of Identified Differentially Expressed Proteins

Conclusions