Use of two-dimensional gel electrophoresis in predictive toxicology: Identification of potential early protein biomarkers in chemically induced hepatocarcinogenesis

Abstract

Our current approach focused on the identification of potential early protein biomarker signatures which are indicative of the carcinogenic processes in rats exposed to 20 mg/kg of the liver carcinogen N-nitrosomorpholine (NNM). Treated liver was investigated at different timepoints. Therefore, proteins were separated by two-dimensional gel electrophoresis as a first step prior to identification of differentially expressed proteins by mass spectrometry. Proteomic analysis of liver samples after one day of exposure revealed significant upregulation of proteins involved in response to cellular stress induced by NNM (superoxide dismutase, heat shock protein 60, peroxiredoxin). Eighteen weeks after withdrawal of NNM, we were able to identify cancer-related proteins in rat liver bearing malignant, transformed cells (caspase-8 precursor, vimentin, Rho GDP dissociation inhibitor). Some of these proteins were already deregulated after three weeks of exposure indicating their potential usefulness as early predictive biomarkers for liver carcinogenicity (annexin A5, fructose-1,6-bisphosphatase). As regulatory toxicology approaches usually include the investigation of carcinogenicity in two-years studies in rodents, especially the detection of early protein biomarker signatures which precede the appearance of neoplasia, demonstrates the high potential of proteomics approaches to substantially reduce the time and costs of carcinogenicity testing.

The characterization of the invasion phenotype of uveal melanoma tumour cells shows the presence of MUC18 and HMG‐1 metastasis markers and leads to the identification of DJ‐1 as a potential serum biomarker

“…[27][28][29] The differentially expressed proteins Rho GDPI 1 and 2, mostly present in the UM primary cell culture, also correlated well with previous reports involving the downregulation of those proteins in late stages of cancer. 30,31 On the other hand, we found proteins previously linked to tumour development or related to cell migration and invasion that were upregulated or exclusively present in the primary cell culture. Interestingly, new proteins were differentially present in the UM cell line like HMG-1, nuclear protein SkiP, and hnRNPA2/B1.…”

Proteomic Analysis of Differentially Expressed Proteins in Peripheral Cholangiocarcinoma

“…Of the over-expressed proteins, those that may have a role in tumorigenesis or that have been linked to other cancers include: 60 S acidic ribosomal protein P0 overexpression which has been linked to proliferation in breast and liver cancer [27], alpha-actinin 4 which is also differentially expressed in hepatocellular carcinoma [28], annexin V which has been shown to be elevated in chemically induced hepatocarcinoma [29]; as have elongation factor 1 delta [17] and ezrin [19]. Other proteins that have also been shown to be elevated in hepatocellular carcinoma include fibrinogen gamma chain precursor [30], glutathione S transferase [31], glycerol-3-phosphate dehydrogenase [32], histone-binding protein RBBP4 [33] and nucleophosmin [34].…”

Differential Liver Protein Expression during Schistosomiasis

“…Such studies have shown that schistosomiasis alters the expression of enzymes involved in the urea cycle, glycolysis, energy metabolism, and other essential metabolic processes (1,17,41), and the alterations have some similarities with other liver-damaging insults (i.e., liver cancer and hepatotoxicity) (22,66). However, it is clear that some changes may be unique to schistosomiasis.…”