| miRNA basics & biogenesis |
Canonical and non-canonical processing; RISC-mediated repression/decay or context-dependent regulation. |
Drosha/DGCR8, Exportin-5, Dicer/TRBP, Ago/RISC; mention of mirtrons and passenger strand roles. |
βClassic pathwayβ cannot be generalized to all miRNAs; non-canonical routes add heterogeneity. |
| OncomiRs (examples) |
miRNAs can promote EMT/invasion/metastasis, proliferation, and therapy resistance by targeting tumor suppressors. |
miR-9βCDH1; miR-10bβHOXD10 / syndecan-1; miR-21βPTEN / PDCD4 / TIMP3; miR-155βSOCS1/RhoA/FOXO3A; miR-210βRAD52 (as described). |
Direct-target claims are context-dependent and may vary across breast cancer subtypes and experimental systems. |
| tsmiRs (examples) |
miRNAs can suppress proliferation/invasion/EMT and promote apoptosis by targeting oncogenic drivers. |
let-7βHMGA2/CCR7/CDK6; miR-7βFAK/EGFR; miR-34βBCL-2/SIRT1/EMT TFs; miR-200βZEB1/2. |
Many tsmiRs exhibit subtype/context-dependent behavior; clinical predictive validity varies. |
| Exosomal miRNAs |
Exosomal packaging provides stability; exosomal miRNAs influence recipient cells (biomarkers + mediators). |
Examples include exosomal miR-21/miR-1246 as biomarker pair; other exosomal miRNAs discussed as influencing invasion/angiogenesis. |
EV isolation/characterization heterogeneity and βcargo assignmentβ can complicate interpretation. |
| Therapy resistance |
miRNA dysregulation links to resistance to endocrine therapy (e.g., tamoxifen/fulvestrant), HER2-targeted therapy, and chemotherapy. |
miR-21, miR-221/222, miR-155, miR-200c, miR-181a appear across resistance sections in provided text. |
Resistance is polygenic/temporal; miRNA effects may be one component rather than a causal driver. |
| miRNA-based therapy |
Strategies include antisense anti-miRNAs, miRNA mimics, sponges/circular RNAs, and delivery systems; translational barriers include delivery and immune effects. |
Mentions miRNA delivery systems (viral vectors, lipid vectors/nanoparticles) and clinical efforts like MRX34 (immune-related side effects). |
Safety/immune response and targeted delivery remain the dominant limiting factors. |