Fig. 4. Cx43 increases the susceptibility of LNCaP cells to cell death induced by anti-Fas antibodies or TRAIL. (A,B) LNCaP cells were left uninfected () or they were infected with Ad-Cx43 () for 12 hours and then treated with 1-1000 ng/ml anti-Fas antibodies (A) or 0.1-1000 ng/ml TRAIL (B) for 48 hours. Cell viability after treatment with anti-Fas antibodies (10 ng/ml) was significantly less in Ad-Cx43 infected LNCaP cells as compared to untreated, infected cells (P<0.0001). Moreover, the viability of Ad-Cx43-infected LNCaP cells treated with 10 ng/ml anti-Fas antibodies was significantly reduced as compared to non-infected cells treated with the same doses of antibodies (P<0.0001). High concentrations of anti-Fas antibodies (100 ng/ml) moderately, but significantly reduced the viability of uninfected LNCaP cells (to 82.0±1.7% for 100 ng/ml and 81.9±2.3% for 1000 ng/ml, respectively; P<0.0001 as compared to untreated cells). Similarly, in Ad-Cx43-infected LNCaP cells, TRAIL concentrations as low as 10 ng/ml induced a significant decrease in cell viability (P<0.0001), but only 1000 ng/ml TRAIL induced a significant decrease in cell viability of uninfected LNCaP cells (viability=86.0±2.2%; P=0.017 as compared to untreated cells).