The functional effects of synthetic miRNA inhibitors are often difficult to predict and detect. Add confidence to your functional microRNA experiments using the let-7c Anti-miR™ miRNA Inhibitor in conjunction with the HMGA2 TaqMan® Gene Expression Assay. This convenient system detects delivery of functional Anti-miR miRNA Inhibitors into human and mouse cells only 24 hours after transfection.
The let-7c miRNA downregulates expression of the HMGA2 gene [1–3] at the mRNA level. Delivery of let-7c Anti-miR miRNA Inhibitor into cells inactivates endogenous let-7c miRNA, causing a reproducible, specific upregulation of HMGA2 expression in only 24 hours (compared to mock-transfected cells or cells transfected with Anti-miR Inhibitor–Negative Control #1). The increase in HMGA2 mRNA levels caused by increasing doses of the let-7c Anti-miR Inhibitor can be conveniently detected and quantified using the HMGA2 TaqMan Gene Expression Assay.

The let-7c/HMGA2 model system is highly useful as a positive control for any Anti-miR experiment and can also be used to optimize conditions used to deliver Anti-miR Inhibitors into cells of interest (Figure 1A). Because let-7c and HMGA2 are ubiquitously expressed, this system can serve as a universal positive control in a variety of human, mouse, and rat cell types, including Hep-G2, A549, ME180, UMR106, and Hepa 1-6. The upregulation of HMGA2 appears to be specific since it is not observed in similar transfections using the Anti-miR-16 Inhibitor (Figure 1B).

Figure 1. Detection of let-7c Anti-miR™ Inhibitor-mediated Upregulation of HMGA2 mRNA Using a TaqMan® Gene Expression Assay (Assay ID: Hs00971725). (A) Optimization experiment: HeLa cells (6 x 103 cells/well; quadruplicate samples) were transfected with let-7c Anti-miR Inhibitor (50 nM) using 0–0.7 µL siPORT™ NeoFX™ Transfection Agent (Cat# AM4510). HMGA2 mRNA levels were measured using real-time RT-PCR 24 hours later. The observed CT values were normalized with results from the 18S rRNA endogenous control. The maximal upregulation of HMGA2 by let-7c Anti-miR Inhibitor (relative to cells transfected Anti-miR Inhibitor—Negative Control #1) is observed using 0.3 µL siPORT NeoFX Agent per well. No cytotoxicity is observed under these conditions. (B) HeLa cells were transfected in triplicate with 50 nM Anti-miR Inhibitors as described for Panel A. Upregulation of HMGA2 mRNA is specifically caused by transfection of let-7c Anti-miR Inhibitor but not by Anti-miR-16 or Anti-miR Inhibitor—Negative Control #1.

Scientific Contributors
Sarah LaMartina, Tera Schaller, and Joe Krebs • Applied Biosystems, Austin, TX