The role of death pathways in the efficacy of photokilling

The beginnings of photodynamic therapy date from 1900 but mechanisms relating to photokilling were unknown until 1991 when Oleinick’s group first described PDT-induced apoptosis. Routes to apoptosis have been determined along with the role of sub-cellular photodamage as a factor in initiation of cell death. We have recently reported on the role of paraptosis, another death mode that can be operative in cells with an impaired apoptotic program. It appears that the sensitivity of malignant cell types to lethal photodamage can be magnified by careful selecting of sub-cellular targets. In this report, recent progress relating to potential routes to improved PDT responses is described.