FIGURE 5.

Effect of Galectin-3 down-regulation and overexpression on NK cytotoxicity. HeLa cells were transfected with an empty vector (EV), Gal-3-specific lentivirus-based shRNA (shGal-3, A), or Gal-3 expression vector (exGal-3, B), and then the cell lysate was prepared and analyzed for Gal-3 expression using immunoblot analysis. GAPDH (A) and β-actin (B) were used as controls. Then transfected HeLa cells were incubated with NK-92 cell clones at effector:target ratios of between 8:1 and 4:1, and the lysis of the target cells was determined using a 4-h europium release assay. NK cell cytotoxicity was normalized to 100% at the most E:T (8:1) ratios. C, MDA-MB-435 cells were transfected with an empty vector or Gal-3-specific lentivirus-based shRNA, and immunoblot analysis was performed as described previously. Flow cytometry was performed to measure CD107a surface expression after coincubation of NK-92 cells with empty vector or shGal-3 MDA-MB-435 cells. The data are representative of two independent experiments and were analyzed using Student's t test. **, p < 0.01; ***, p < 0.0001.