Cellular Protein Extraction and Analysis

Cells were harvested with RIPA buffer (Thermo Fisher Scientific, Oslo, Norway) containing phosphatase and protease inhibitors (No. 78420 and 78430, respectively, Thermo Fisher Scientific, Oslo, Norway) and sonicated (Bioruptor 300, Diagenode, Belgium) for 5 min. The protein concentration was measured by Pierce™ BCA Protein Assay Kit (Thermo Fisher Scientific, Oslo, Norway) according to the manufacturer’s instructions. Immunoblotting was performed as described previously [32 (link)]. Primary antibodies anti-HER2 (rabbit-anti-human, 0.66 μg/mL), β-Actin (rabbit-anti-human, 0.67 μg/mL) and HRP-conjugated antibody (goat-anti-rabbit, 0.33 μg/mL) were used. Blots were visualized by ChemiDoc MP imaging system (Bio-Rad, Oslo, Norway).