miRNAs-enriched Trout Embryonic Extracts promote the reversion of the malignant phenotype in liver tumor cells

Since many of the antitumor therapies currently used in clinical practice to treat patients affected by hepatoblastoma and hepatocellular carcinoma are highly toxic and often ineffective, this study aims to explore the therapeutic potential of fish embryonic extracts, which has been previously reported. Indeed, considering the well-documented ability of the embryonic environment to influence cell fate and redirect tumor cells toward a more differentiated and less malignant phenotype, and given the demonstrated efficacy of zebrafish embryonic extracts in promoting tumor reversion in various cancer models as well as improving patient outcomes in clinical contexts, the study presented here aims to further contribute to the scientific knowledge in this field, following the principles underlying differentiation therapies. Since most metastatic circulating tumor cells, as well as those from primary hepatoblastoma and hepatocellular carcinoma, exhibit cellular plasticity and partial co-expression of epithelial to mesenchymal transition (EMT) markers, the analyses were initiated by assessing the effects of embryonic extracts on cell motility and invasion, as well as by measuring EMT markers expression following treatment. The initial experiments were conducted using nine different embryonic stages of Oncorhynchus Mykiss (O. Mykiss) at three concentrations. Subsequently, the three most effective stages and the most effective concentration were identified. The embryonic stages corresponding to the end of gastrulation and the onset of neural crest formation, referred to as P4, P5, and P7, proved to be the most effective in inhibiting several macroscopic and molecular processes involved in metastasis formation when administered to cells at a concentration of 30 μg/mL, normalized to total protein content. Furthermore, the extracts demonstrated their ability in modulating miRNA expression within cancer cells. Interestingly, most of the results are consistent with previous observations obtained using zebrafish extracts.