Lethal-7 microRNA family (let-7) (let-7)

The Lethal-7 (let-7) microRNA family is a highly conserved group of non-coding RNAs that play a critical role in regulating cell proliferation and differentiation (Roush & Slack, 2008). In humans, the family includes members such as let-7a, let-7b, let-7c, let-7d, let-7e, let-7f, let-7g, let-7i, and miR-98, which are often clustered together in the genome (Bussing et al., 2008). These microRNAs function as potent tumor suppressors by binding to the 3' untranslated regions (UTRs) of target mRNAs, including major oncogenes like RAS, MYC, and HMGA2, thereby inhibiting their translation or inducing degradation (Thornton & Gregory, 2012). Downregulation of let-7 is a hallmark of many malignancies and is frequently driven by the RNA-binding protein Lin28, which blocks the processing of let-7 precursors (Balzeau et al., 2017). Therapeutic approaches focus on restoring let-7 activity through synthetic miRNA mimics or by using small molecules to disrupt the Lin28/let-7 interaction (Wang et al., 2018). Despite their therapeutic potential, challenges include achieving efficient tissue-specific delivery and avoiding unintended silencing of genes in healthy tissues.

Other names

let-7miR-let-7Lethal-7let-7a-imiR-98let-7 family microRNAs

Restoration of tumor-suppressive microRNA levels via synthetic mimics or enhancement of endogenous biogenesis by inhibiting Lin28-mediated suppression (Wang et al., 2018; Balzeau et al., 2017).