Lethal-7 family microRNAs (let-7)

The Lethal-7 (let-7) family of microRNAs is one of the most extensively studied groups of non-coding RNAs, originally discovered in C. elegans as a key regulator of developmental timing. In humans, the let-7 family consists of multiple members (e.g., let-7a through let-7i) that function primarily as tumor suppressors by downregulating potent oncogenes such as RAS, MYC, and HMGA2. These miRNAs play a critical role in promoting cell differentiation and inhibiting the 'stemness' of cancer cells, making their downregulation a common hallmark in various malignancies, including lung, breast, and ovarian cancers. Beyond oncology, let-7 is involved in glucose metabolism and cardiovascular health, where it modulates inflammatory responses and fibrotic pathways. Therapeutic strategies currently focus on the use of synthetic let-7 mimics to restore tumor-suppressive activity or antagomirs to inhibit let-7 in specific contexts like fibrosis. However, clinical advancement remains challenged by the need for precise delivery systems and the management of potential off-target effects associated with broad mRNA silencing.

Other names

let-7 familyhsa-let-7Lethal-7let-7 miRNA

Post-transcriptional gene silencing via mRNA degradation or translational repression by binding to the 3' untranslated region (UTR) of target mRNAs.