Figure 2.

PS-dose dependent photoreactions in primary lung ECs. Confluent monolayers of N-EC and T-EC (L374, passage 3) were treated with increasing concentrations of HPPH or HPPH-Lac for 24 h in RPMI containing 10% FBS followed by a chase for 24 h in PS-free medium. (A) The cell-associated PS fluorescence was determined by microscopy. Only the fluorescent images of T-EC cells at 400X treated with the highest PS concentration are shown to demonstrate the distinct subcellular distribution. (B) The levels of fluorescence in each culture were quantitated and expressed in arbitrary fluorescence units (FU). After 9 min light treatment (3 J/cm²) the products of the PS-mediated photoreaction were determined by immunoblot analyses including the covalent crosslinking of STAT3, the loss of EGFR and the activation of p38 kinase. (C) In parallel cultures, the percentage of PDT-surviving ECs were determined after additional 24 h-incubation of the light-treated cells in RPMI containing10% FBS.