**2.5 Quantitation of miR-665 in transfected cells**

Mouse neuroblastoma cells were transfected with 100 nM miR-665 mimic and negative control cel-miR-67. 48 h post-transfection, total RNA was extracted from three biological replicates per treatment using the Qiagen RNEasy mini kit. miR-665 was quantitated via realtime qPCR by Arraystar, Inc. (Rockville, MD, USA).

Real-time PCR was performed for each RNA sample to quantify miR-665 and the housekeeping gene, U6. According to the standard curve, mRNA concentrations in each sample are determined directly using Rotor-Gene Real-Time Analysis software v.6.0 and the 2∆∆Ct method.

### **2.6 Total HDAC activity**

Total HDAC activity was measured in 50–75ug of protein from cell extracts prepared from untreated, or negative control miRNA- or miR 665-transfected cells using the Biovision kit (#K331–100). Acetylated HDAC substrate and other reagents were added according to the manufacturer's instructions and the final deacetylated product was read at 405 nm in a plate reader.
