microRNA-99 family (miR-99)

The microRNA-99 (miR-99) family is a highly conserved group of non-coding RNAs that includes miR-99a, miR-99b, and miR-100. These microRNAs play a critical role in post-transcriptional gene regulation by binding to the 3' untranslated regions (UTRs) of various target mRNAs, most notably those involved in the PI3K/AKT/mTOR signaling pathway [1, 2, 8]. In many solid tumors, such as prostate, lung, and breast cancers, miR-99 family members typically function as tumor suppressors and are frequently downregulated, which leads to the overexpression of oncogenic targets like mTOR, IGF1R, and AKT1 [1, 7, 12]. However, their role can be context-dependent, as they have been observed to act as oncomirs in certain types of leukemia [3]. Beyond oncology, the miR-99 family is involved in regulating immune responses, dermal wound healing, and cell differentiation [3, 8]. Due to their dysregulation in disease, they are being investigated as potential diagnostic and prognostic biomarkers [1, 10]. Therapeutic approaches currently under research include the use of miRNA mimics to restore tumor-suppressive activity or antagomirs to inhibit oncogenic functions, though challenges remain regarding delivery and off-target effects [1, 18].

Other names

miR-99miR-99amiR-99bmiR-100MIR99MIR100MIR99AMIR99B

Post-transcriptional gene silencing by binding to the 3' untranslated region (UTR) of target mRNAs, such as mTOR, IGF1R, and AKT1, leading to translational inhibition or mRNA degradation.