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MicroRNA-199 (miR-199) is a family of
small non-coding RNAs comprising miR-199a and
miR-199b, with mature strands including
miR-199a-5p, miR-199a-3p,
miR-199b-5p, and miR-199b-3p. These
microRNAs regulate gene expression by binding target mRNAs and promoting
transcript degradation or translational repression. In many cancers,
miR-199 ↓ is the more commonly reported pattern, and
restoration or miR-199 ↑ frequently suppresses
proliferation, migration, invasion, epithelial-mesenchymal transition,
tumour growth, and treatment resistance while promoting apoptosis.
Reported downstream targets and pathways include HIF-1α, mTOR/RHEB,
YAP1, ITGA3, PAK4/MEK/ERK, KRAS/AKT/ERK, IKKβ/NF-κB, and RGS17.
However, miR-199 can have oncogenic effects in selected cancers, so its
direction must be recorded according to tumour type, mature strand,
specimen, and experimental context.
Cancer review;
Tumour-suppressive example.
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