Figure 5.

Effect of hemichannels on apoptosis. (a) The inhibition of Cx43 hemichannels with a blocking Pep (50 μM, Pep) does not affect the rate of apoptosis induced by SN (10 μM, 5 h) or α-Fas (100 ng/ml, 5 h) in HeLa-Cx43 cells. A non-inhibitory ConPep (50 μM) was used as a control. Apoptosis was measured by annexin V-FITC/PI staining and quantified using flow cytometry. The percentage of apoptotic cells from the total cell number is expressed as mean±S.E.M.; n≥6 in at least three different cell cultures. (b) The uptake of PI (mean red fluorescence of single cells) by HeLa-Cx43 cells from the culture medium could be stimulated by opening the hemichannels with ATP (50 μM) and was efficiently blocked by preincubation with a hemichannel-blocking Pep (50 μM). Treatment with SN (10 μM) did not affect the PI uptake. A non-inhibitory Pep (ConPep) was used as a control. PI uptake of single cells is displayed as mean±S.E.M.; n≥80–160 cells in at least three different cell cultures *P<0.001 versus untreated, SN and ATP+ConPep, NG