MicroRNA 551b (miR-551b)

MicroRNA 551b (miR-551b) is a small, non-coding RNA molecule transcribed from the MIR551B gene, located on chromosome 3q26.2. It is involved in the post-transcriptional regulation of gene expression by binding to the 3'-UTR of target mRNAs, leading to mRNA degradation or translational repression. miR-551b has a significant role in cancer biology, where it regulates proliferation, migration, invasion, apoptosis, and chemoresistance in multiple tumor types. The expression of miR-551b is often decreased in various cancers, and its restoration can suppress tumor growth and metastasis. Specifically, in breast and cholangiocarcinoma, miR-551b acts as a tumor suppressor by inhibiting key targets such as Cyclin D1. In other contexts, such as ovarian cancer, it has been reported to act as an oncogene. miR-551b is considered a prognostic biomarker and a potential therapeutic target, though no approved drugs directly target this miRNA, and clinical translation is limited by challenges common to RNA therapeutics

Other names

hsa-miR-551bMIRN551Bmir-551bhsa-mir-551bMIR551BmiR-551b-3p

Modulates downstream protein expression relevant for tumor cell proliferation and apoptosis (e.g., targets like Cyclin D1/CCND1, MUC1) Influences chemoresistance pathways, including catalase/ROS/MUC1 signaling