Porcine TM cells were washed twice in cold PBS and harvested using lysis buffer (150 mM NaCl, 20 mM Tris [pH 8.0], 1% NP-40, 0.1% SDS, and 1× protease inhibitor cocktail; Thermo Scientific, Rockford, IL) with a cell scraper. Tissue was homogenized in 20 mM Tris buffer, pH 7.4 containing 1 mM sodium orthovanadate, 0.2 mM EDTA, 0.2 mM PMSF, 0.1 M NaCl, 50 mM NaF, 1× protease inhibitor cocktail (Thermo Scientific). Protein concentration was determined using Micro BCA Protein Assay Kit (Pierce, Rockford, IL). Equal amounts of protein were separated by 10% SDS-PAGE gels and transferred to polyvinylidene fluoride membrane (Bio-Rad). Membranes were blocked with 5% nonfat dry milk and incubated overnight at 4°C with the primary antibodies anti-CD39, -CD73 (Santa Cruz Biotechnology, Santa Cruz, CA). They were incubated with secondary antibodies conjugated to horseradish peroxidase for 1 hour at room temperature. Immunoreactive bands were visualized by chemiluminescence using ECL Plus Western Blotting System (GE Healthcare, Piscataway, NJ). Membranes were reprobed with antitubulin β antibody (Sigma) for protein loading control.