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

Analysis of Unfolded Protein Response Activation in Colon Adenocarcinoma Epithelial Cells: A Proteomic Study

PURPOSE

High throughput technologies have identified molecular patterns in colorectal cancer (CRC) cells, aiding in modeling responses to anti-cancer treatments. The different responses observed depend on the type of cancer, the tumour grade and the functional programme of the cancer cells. Recent studies suggest that the unfolded protein response (UPR), autophagy and apoptosis could be involved in treatment resistance mechanisms by interacting with the tumour microenvironment (TME).

EXPERIMENTAL DESIGN

We analysed by LC-MS/MS the proteome of two representative colon adenocarcinoma epithelial cell lines from different tumour grades (CCL-233 and CCL-221) at the basal state or after the UPR induction.

RESULTS

Cell lines expressed a different proteome on about 10% of their total proteins identified, especially on UPR, autophagy and apoptosis pathways proteins at basal state. After UPR induction, the proteome of the cells was modified with a greater adaptive response to cellular stress in CCL-221 cells where the UPR was strongly activated at the basal state.

CONCLUSIONS AND CLINICAL RELEVANCE

CRC cell lines at different tumour grades expressed different functional programmes at the proteomic level and were characterised by different responses to the UPR induction. This study suggests that baseline cancer cell stress status could have an impact on the efficiency of cancer therapies.

In-Depth Proteomic Analysis of Paraffin-Embedded Tissue Samples from Colorectal Cancer Patients Revealed TXNDC17 and SLC8A1 as Key Proteins Associated with the Disease

A deeper understanding of colorectal cancer (CRC) biology would help to identify specific early diagnostic markers. Here, we conducted quantitative proteomics on FFPE healthy, adenoma, and adenocarcinoma tissue samples from six stage I sporadic CRC patients to identify dysregulated proteins during early CRC development. Two independent quantitative 10-plex TMT experiments were separately performed. After protein extraction, trypsin digestion, and labeling, proteins were identified and quantified by using a Q Exactive mass spectrometer. A total of 2681 proteins were identified and quantified after data analysis and bioinformatics with MaxQuant and the R program. Among them, 284 and 280 proteins showed significant upregulation and downregulation (expression ratio ≥1.5 or ≤0.67, p-value ≤0.05), respectively, in adenoma and/or adenocarcinoma compared to healthy tissue. Ten dysregulated proteins were selected to study their role in CRC by WB, IHC, TMA, and ELISA using tissue and plasma samples from CRC patients, individuals with premalignant colorectal lesions (adenomas), and healthy individuals. In vitro loss-of-function cell-based assays and in vivo experiments using three CRC cell lines with different metastatic properties assessed the important roles of SLC8A1 and TXNDC17 in CRC and liver metastasis. Additionally, SLC8A1 and TXNDC17 protein levels in plasma possessed the diagnostic ability of early CRC stages.

Carry-Over of Zearalenone and Its Metabolites to Intestinal Tissues and the Expression of CYP1A1 and GSTπ1 in the Colon of Gilts before Puberty

The objective of this study was to evaluate whether low doses of zearalenone (ZEN) affect the carry-over of ZEN and its metabolites to intestinal tissues and the expression of CYP1A1 and GSTπ1 in the large intestine. Prepubertal gilts (with a BW of up to 14.5 kg) were exposed in group ZEN to daily ZEN5 doses of 5 μg/kg BW (n = 15); in group ZEN10, 10 μg/kg BW (n = 15); in group ZEN15, 15 μg/kg BW (n = 15); or were administered a placebo (group C, n = 15) throughout the experiment. After euthanasia, tissues were sampled on exposure days 7, 21, and 42 (D1, D2, and D3, respectively). The results confirmed that the administered ZEN doses (LOAEL, NOAEL, and MABEL) were appropriate to reliably assess the carry-over of ZEN. Based on the observations made during 42 days of exposure to pure ZEN, it can be hypothesized that all mycotoxins (ZEN, α-zearalenol, and β-zearalenol) contribute to a balance between intestinal cells and the expression of selected genes encoding enzymes that participate in biotransformation processes in the large intestine; modulate feminization processes in prepubertal gilts; and elicit flexible, adaptive responses of the macroorganism to mycotoxin exposure at the analyzed doses.