Fig. 1.

Direct and indirect effects of PDT treatment on Hsp70 gene expression in vitro. Cultured LLC cells were treated with PDT (Photofrin™ 20 μg/ml for 24 h followed by 1 J/cm²). They were then kept further in culture for 4 or 8 h either alone or co-incubated (contained in separate culture inserts) with untreated Hepa 1-6 cells. At the end of the incubation period, PDT-treated LLC cells and Hepa 1-6 cells were collected for quantitative RT-PCR-based analysis of Hsp70 gene expression. The results were normalized to corresponding controls using PDT-untreated LLC cells for the left columns and Hepa 1-6 cells co-incubated with PDT-untreated LLC cells for the right columns. N = 4, bars are SD; *p < 0.05, statistically significant difference compared to controls