Helminth infection-induced carcinogenesis: spectrometric insights from the liver flukes, Opisthorchis and Fasciola

Cancerogenic parasites in veterinary medicine: a narrative literature review

Parasite infection is one of the many environmental factors that can significantly contribute to carcinogenesis and is already known to be associated with a variety of malignancies in both human and veterinary medicine. However, the actual number of cancerogenic parasites and their relationship to tumor development is far from being fully understood, especially in veterinary medicine. Thus, the aim of this review is to investigate parasite-related cancers in domestic and wild animals and their burden in veterinary oncology. Spontaneous neoplasia with ascertained or putative parasite etiology in domestic and wild animals will be reviewed, and the multifarious mechanisms of protozoan and metazoan cancer induction will be discussed.

Similarities and differences among the Opisthorchiidae liver flukes: insights from Opisthorchis felineus

The foodborne liver trematode Opisthorchis felineus (Rivolta, 1884) is a member of the triad of phylogenetically related epidemiologically important Opisthorchiidae trematodes, which also includes O. viverrini (Poirier, 1886) and Clonorchis sinensis (Loos, 1907). Despite similarity in the life cycle, Opisthorchiidae liver flukes also have marked differences. Two species (O. viverrini and C. sinensis) are recognized as Group 1A biological carcinogens, whereas O. felineus belongs to Group 3A. In this review, we focus on these questions: Are there actual differences in carcinogenicity among these 3 liver fluke species? Is there an explanation for these differences? We provide a recent update of our knowledge on the liver fluke O. felineus and highlight its differences from O. viverrini and C. sinensis. In particular, we concentrate on differences in the climate of endemic areas, characteristics of the life cycle, the range of intermediate hosts, genomic and transcriptomic features of the pathogens, and clinical symptoms and morbidity of the infections in humans. The discussion of these questions can stimulate new developments in comparative studies on the pathogenicity of liver flukes and should help to identify species-specific features of opisthorchiasis and clonorchiasis pathogenesis.

Global changes in gene expression related to Opisthorchis felineus liver fluke infection reveal temporal heterogeneity of a mammalian host response

The food-borne trematode Opisthorchis felineus colonizes bile ducts of the liver of fish-eating mammals including humans. Among chronically infected individuals, this opisthorchiasis involves hepatobiliary problems, including chronic inflammation, periductal fibrosis, biliary intraepithelial neoplasia, and even cholangiocarcinoma. Despite numerous studies at the pathomorphological level, the systemic response and cellular pathogenesis of these disorders are not well studied.

To conduct in-depth research and to gain insights into the mechanism by which O. felineus infection causes precancerous liver lesions, we (i) applied a next-generation-sequencing–based technology (high-throughput mRNA sequencing) to identify differentially expressed genes in the liver of golden hamsters infected with O. felineus at 1 and 3 months postinfection and (ii) verified the most pronounced changes in gene expression by western blotting and immunohistochemistry.

A total of 2151 genes were found to be differentially expressed between uninfected and infected hamsters (“infection” factor), whereas 371 genes were differentially expressed when we analyzed “time × infection” interaction. Cluster analysis revealed that sets of activated genes of cellular pathways were different between acute (1 month postinfection) and chronic (3 months postinfection) opisthorchiasis. This enriched KEGG pathways were “Cell adhesion molecules”, “Hippo signaling”, “ECM-receptor interaction”, “Cell cycle”, “TGF-beta”, and “P53 signaling”. Moreover, epithelial–mesenchymal transition was the most enriched (q-value = 2.2E-07) MSigDB hallmark in the set of differentially expressed genes of all O. felineus–infected animals. Transcriptomic data were supported by the results of western blotting and immunohistochemistry revealing the upregulation of vimentin, N-cadherin, and α-smooth muscle actin postinfection.

Our data expand knowledge about global changes in gene expression in the O. felineus–infected host liver and contribute to understanding the biliary neoplasia associated with the liver fluke infection.

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A total of 2151 genes were found to be differentially expressed during the infection.

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Epithelial-Mesenchymal Transition was the most enriched process in the infected animals.

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Different pathways were activated between acute and chronic opisthorchiasis.