Characterization of U937 cells stably transfected with CASP2L/AS.

U937/AS1 and U937/AS2 are 2 mixed cell populations transfected with CASP2L/AS. U937/neo and U937/AS3 are 2 clones selected after transfection with empty pTARGET and CASP2L/AS vectors, respectively. (A) Western blot analysis of procaspase-2L expression in U937/AS1 and U937/AS2 cells. (B) Western blot analysis of procaspase-2L, -3, -7, -8, FADD, and Fas expression in U937/neo and U937/AS3 cells. HSC-70 expression level was used for loading control. (C) Flow cytometry analysis of Fas expression (open area) on plasma membrane of U937/neo and U937/AS3 cells. An isotype-matched nonrelevant Ab was used as negative control (filled area). (D) Confocal microscopy analysis of Fas expression in control and FasL (5 U/mL; 3 hours) treated U937/neo and U937/AS3 cells (magnification × 40).