Effect of G3 on endothelial cells. (a) G3-containing medium enhances cell attachment and promotes greater cell viability. Culture medium in subconfluent endothelial cell cultures was replaced with 1% FBS/medium that had been preincubated with G3- or vector-transfected cells for 5 days. Two days after medium replacement, spent medium from vector-transfected cells promoted the detachment of cells from plates while spent medium from G3-transfected cells did not. (b) After cell detachment, cultures were washed, and the adherent cells were harvested and counted (mean number/field + SD). The difference in cell viability between cultures treated with medium from G3- and vector-transfected cells was significant (p < 0.01). This figure also demonstrates that G3-containing medium enhances cell proliferation and reduces cell apoptosis. (c) One day after medium change, cells treated with medium from vector-transfected cells underwent apoptosis, while cells treated with G3-containing medium grew normally. (d) DNA was prepared from cytoplasmic and nuclear fractions and subjected to agarose gel electrophoresis. DNA laddering was detected in cells treated with medium from vector-transfected cells.