Abstract
During host stress response against virus infection, some animal microRNAs (miRNAs) can be upregulated to restore the virus-caused metabolic disorder of host cells via suppressing the expressions of miRNAs' target genes. These antiviral miRNAs may have antitumor capacity, because tumorigenesis results from metabolic disorder of cells. However, this subject has not been explored. In this study, the results showed that shrimp miR-34, which was upregulated during white spot syndrome virus (WSSV) infection, had antiviral activity in shrimp. The expression of shrimp miR-34 in breast cancer cells and in mice suppressed the growth and metastasis of breast cancer by targeting human CCND1, CDK6, CCNE2, E2F3, FOSL1, and MET genes in a cross-phylum manner. The results of this study indicated that miRNAs with antiviral activities can be promising sources for antitumor drug discovery.