microRNA-34 family: From mechanism to potential applications

microRNA-34, a highly conserved microRNA in evolution, is of great interest in recent years. miR-34 regulates multiple targets and performed many functions in cells, such as (1) those mediated by targeting ALDH2, Atf1, Bcl-2 have been implicated in cancer cell apoptosis; (2) it targets CCNE2, CDK4, CDK6 and others to regulate the cell cycle; and (3) it regulates immune homeostasis in Drosophila through Dlg1, Eip75B and others. Meanwhile, miR-34 family is a multifunctional miRNA family identified to be pivotal in organ development, organismal or organ senescence, stress response, spermatogenesis and signal transduction. In this review, we focus on the emerging roles of miR-34 family in mammals, arthropods and Nematoda by discussing novel functions of old and new targets, mechanisms identified to mediate or interact by miR-34, which provides references for screening of tumor target drugs and creation of green target biopesticide.