Light fractionated ALA-PDT enhances therapeutic efficacy in vitro; the influence of PpIX concentration and illumination parameters

BRUIJN H, ; CASAS A; DI VENOSA G; GANDARA L; STERENBORG H; BATLLE A; ROBINSON D

Photochemical and Photobiological Sciences

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2013 vol. 12 p. 241 - 245

1474-905X

Light fractionation, with a long dark interval, significantlyincreases the response to ALA-PDT in pre-clinical models and innon-melanoma skin cancer. We investigated if this increase inefficacy can be replicated in PAM 212 cells in vitro. The resultsshow a significant decrease in cell survival after light fractionationwhich is dependent on the PpIX concentration and light dose ofthe first light fraction. This study supports the hypothesis that anunderlying cellular mechanism is involved in the response to lightfractionation in which a first light fraction leads to sub-lethallydamaged cells that are sensitised to a second light fraction2 hours later. The current study reveals the in vitro circumstancesunder which we can investigate the cellular pathways involved.