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| Figure 1: Levels of C16-ceramide, dihydro C16-ceramide, S1P and sphingosine in the supernatants of cultured SCCVII cells after their treatment by PDT. Cultured SCCVII cells were treated by Photofrin-PDT by incubating them with Photofrin (20 μg/ml) for 18 hours followed by exposure to 1 J/cm2 of 630 ± 10 nm light. The cells were then further incubated at 37°C either in standard growth medium supplemented with 10% FBS for indicated time intervals (a) or in serum-free medium (Ex-cell NS0) for 3 hours (b). The culture supernatants were then collected and the levels of various SL species determined using electrospray ionization double MS either from whole supernatants or from exosome fraction of these supernatants. The results are presented as the concentration of particular SL in pmoles/ml in supernatant of cell monolayer consisting of 1×106 cells. The percentages of total C16- ceramide and dhC16-ceramide contained in the exosome fraction of supernatants collected at 3 hours post PDT are depicted in the Figure 1a insert. The bars denote SD; *=statistically significant difference from the value in supernatants from untreated SCCVII cells. |
