Proliferation of ASM cells based on DNA content was measured as described previously (70 (link)). Briefly, ASM cells were grown in 96-well plates (~5,000 cells/ well), serum-deprived, transfected with siRNA, exposed to 1% CSE for 48h and incubated with CyQuant NF (Invitrogen) for 30 min. Dye (CyQuant) binding to DNA (fluorescence) was measured on a FlexStation3 microplate reader (Molecular Devices, Sunnyvale, CA). Dye calibrations and normalization were performed, as previously described (70 (link)).