Total RNA extraction: was performed using the RNeasy Mini Kit (Qiagen, Basel, Switzerland), in the absence of DNAse treatment. RNA quality was assessed using the RNA 6000 Nanochip assay (Agilent Technologies, Meno Park, USA) and RNA concentration was determined using the ND-1000 spectrophotometer (Nanodrop Technologies, Wilmington, USA). Three independent experiments were performed.