Total RNA was prepared using an RNeasy mini kit (Qiagen, Valencia, CA, USA) from cells grown in 96-well plates (around 10 000 cells per well). qRT-PCR using TaqMan primer probe sets were performed essentially as described previously (16 (link)). Briefly, ∼50 ng total RNA in 5 μl water was mixed with 0.3 μl primer probe sets containing forward and reverse primers (10 μM of each) and fluorescently labeled probe (3 μM), 0.3 μl RT enzyme mix (Qiagen), 4.4 μl RNase-free water, and 10 μl of 2× PCR reaction buffer in a 20 μl reaction. Reverse transcription was performed at 48°C for 10 min, 40 cycles of PCR were conducted at 94°C for 20 s and 60°C for 20 s using the StepOne Plus RT-PCR system (Applied Biosystems, Phoenix, AZ, USA). The mRNA levels were normalized to the amount of total RNA present in each reaction as determined for duplicate RNA samples by Ribogreen assay (Life Technologies).