Fig. 4.
Proteolytic processing of Trop-2 in tumor cells. (A) Western blotting analysis of Trop-2 cleavage in normal epidermal cells and skin tumors (SCC, squamous cell carcinoma; BCC, basal cell carcinoma). Red arrow, cleaved Trop-2. MW markers are indicated. Ponceau red staining and western blotting for β-actin were used as controls of protein loading. (B) Western blotting analysis of Trop-2 cleavage in normal skin samples. Red arrow, absence of Trop-2 cleavage at R87-T88. MW markers are indicated. Ponceau red staining, control of protein loading. (C) Trop-2 cleavage patterns in vitro and in vivo. Western blotting of transformed MTE4-14/Trop-2 transfectants and cancer cells either transfected with or endogenously expressing Trop-2 as indicated, grown in culture (left) or as tumors in nude mice (right). T2: TROP2-transfected cells; T2hi, T2lo: TROP2-transfected NS-0 cells selected to express TROP2 at high or low levels, respectively. Red arrow, cleaved Trop-2. (Color version of figure is available online.)