Proteomic analysis of low- and high-grade human colon adenocarcinoma tissues and tissue-derived primary cell lines reveals unique biological functions of tumours and new protein biomarker candidates

Abstract

Background Colon cancer is the third most common cancer and second highest cause of cancer deaths worldwide. The aim of the study was to find new biomarkers for diagnosis, prognosis and therapeutic drug targets for this disease. Methods Four low-grade and four high-grade human colon adenocarcinoma tumours with patient-matched normal colon tissues were analysed. Additionally, tissue-derived primary cell lines were established from each tumour tissue. The cell lines were validated using DNA sequencing to confirm that they are a suitable in vitro model for colon adenocarcinoma based on conserved gene mutations. Label-free quantitation proteomics was performed to compare the proteomes of colon adenocarcinoma samples to normal colon samples, and of colon adenocarcinoma tissues to tissue-derived cell lines to find significantly differentially abundant proteins. The functions enriched within the differentially expressed proteins were assessed using STRING. Proteomics data was validated by Western blotting. Results A total of 4767 proteins were identified across all tissues, and 4711 across primary tissue-derived cell lines. Of these, 3302 proteins were detected in both the tissues and the cell lines. On average, primary cell lines shared about 70% of proteins with their parent tissue, and they retained mutations to key colon adenocarcinoma-related genes and did not diverge far genetically from their parent tissues. Colon adenocarcinoma tissues displayed upregulation of RNA processing, steroid biosynthesis and detoxification, and downregulation of cytoskeletal organisation and loss of normal muscle function. Tissue-derived cell lines exhibited increased interferon-gamma signalling and aberrant ferroptosis. Overall, 318 proteins were significantly up-regulated and 362 proteins significantly down-regulated by comparisons of high-grade with low-grade tumours and low-grade tumour with normal colon tissues from both sample types. Conclusions The differences exhibited between tissues and cell lines highlight the additional information that can be obtained from patient-derived primary cell lines. DNA sequencing and proteomics confirmed that these cell lines can be considered suitable in vitro models of the parent tumours. Various potential biomarkers for colon adenocarcinoma initiation and progression and drug targets were identified and discussed, including seven novel markers: ACSL4, ANK2, AMER3, EXOSC1, EXOSC6, GCLM, and TFRC.

Structural characterization of a sulfated polysaccharide from Gracilariopsis lemaneiformis and its potentiation of cisplatin antitumor activity in Colon-26 carcinoma tumor-bearing mice by inducing ferroptosis

“…The combination treatment significantly increased the protein expression of Tfrc, which is a potential biomarker for colon adenocarcinoma initiation and progression and drug targets. 34 Dysregulated iron metabolism in CRC patients is highly correlated with their poor prognosis, and the iron transporter protein Tfrc mediates iron transport, promotes Tfrc mRNA stability, increases ROS production and iron death sensitivity, and enhances the host immune response to cancer. 35 In addition, Apoe expression associated with cholesterol metabolism is elevated, with similar results in adipocytes treated with ferric ammonium citrate resulting in an increased Apoe expression.…”

The initiator of neuroexcitotoxicity and ferroptosis in ischemic stroke: Glutamate accumulation

“…Ferroptosis is a newly identified form of cell death caused by iron-dependent lipid peroxidation. Which leads to cell membrane damage and the accumulation of reactive lipid hydroperoxides to lethal levels ( Munro et al, 2022 ). Our original knowledge of the molecular mechanisms of ferroptosis stemmed from studies using small molecule compounds to selectively inhibit cancer cells with oncogenic RAS mutations ( Chen et al, 2021 ; Andreani et al, 2022 ).…”