miR-155: on the crosstalk between inflammation and cancer.
MicroRNAs are short non-coding RNAs that posttranscriptionally modulate the expression of multiple target genes and are thus implicated in a wide array of cellular and developmental processes. miR-155 is processed from BIC, a non-coding transcript highly expressed in both activated B and T cells and in monocytes/macrophages. miR-155 levels change dynamically during both hematopoietic lineage differentiation and the course of the immune response. Different mouse models developed recently indicate that miR-155 plays a critical role during hematopoiesis and regulates lymphocyte homeostasis and tolerance. A moderate increase of miR-155 levels is observed in many types of malignancies of B cell or myeloid origin, and transgenic over-expression of miR-155 in mice results in cancer. While the high levels of miR-155 reached transiently during the course of the immune response remain unharmful for the organism, the reason why a moderate up-regulation of miR-155 can lead to cancer remains obscure. As prolonged exposure to inflammation can lead to cancer, the permanent up-regulation of miR-155 might be a link between the two. Therefore, designing miR-155 based therapies will require a better understanding of the molecular basis of its action as well as of how miR-155 levels are regulated in a cell-specific manner.
Tili
Esmerina
E
Ohio State University, Department of Molecular Virology, Immunology, and Medical Genetics, Comprehensive Cancer Center, Columbus, Ohio 43210, USA.
Croce
Carlo M
CM
Michaille
Jean-Jacques
JJ
D000818:Animals; D015870:Gene Expression; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000235:genetics* / Q000276:immunology*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000276:immunology*; D009369:Neoplasms / Q000235:genetics* / Q000276:immunology*
C524942:MIRN155 microRNA, human; D035683:MicroRNAs