| General information | Literature | Expression | Regulation | Mutation | Interaction |
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Basic Information |
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|---|---|
Gene ID | 406947 |
Name | MIR155 |
Synonymous | MIRN155|miRNA155;microRNA 155;MIR155;microRNA 155 |
Definition | hsa-mir-155 |
Position | 21q21.3 |
Gene type | ncRNA |
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Title |
Abstract |
| MicroRNA-155 suppresses activation-induced cytidine deaminase-mediated Myc-Igh translocation. | microRNAs (miRNAs) are small noncoding RNAs that regulate vast networks of genes that share miRNA target sequences. To examine the physiologic effects of an individual miRNA-mRNA interaction in vivo, we generated mice that carry a mutation in the putative microRNA-155 (miR-155) binding site in the 3-untranslated region of activation-induced cytidine deaminase (AID), designated Aicda(155) mice. AID is required for immunoglobulin gene diversification in B lymphocytes, but it also promotes chromosomal translocations. Aicda(155) caused an increase in steady-state Aicda mRNA and protein amounts by increasing the half-life of the mRNA, resulting in a high degree of Myc-Igh translocations. A similar but more pronounced translocation phenotype was also found in miR-155-deficient mice. Our experiments indicate that miR-155 can act as a tumor suppressor by reducing potentially oncogenic translocations generated by AID. |
| microRNA-155 is downregulated in gastric cancer cells and involved in cell metastasis. | microRNA-155 (miR-155), an important multifunctional microRNA, has been implicated in the development of multiple solid tumors, yet, its role in gastric cancer cells has not been fully elucidated. In this study, we find that miR-155 was significantly downregulated in gastric cancer cell lines compared with an immortalized gastric epithelial cell line (GES-1). Overexpression of miR-155 in SGC-7901 and MKN-45 gastric cancer cells dramatically suppressed cell migration, invasion and adhesion in vitro. Overexpression of miR-155 significantly reduced the protein levels of SMAD2 and repressed the activity of a luciferase reporter containing one of the two predicted miR-155 binding sites in SMAD2 3-UTR, indicating that SMAD2 may be a miR-155 target gene. miR-155 expression was also remarkably restored by a DNA demethylating agent (5-Aza-2-deoxycytidine) in SGC-7901 and MKN-45 gastric cancer cells. Taken together, these data suggest that miR-155 may function as a tumor suppressor to regulate gastric cancer cell metastasis by targeting SMAD2, and its downregulation in gastric cancer cells may be partly ascribed to DNA methylation. |