Responses of cancer cells induced by photodynamic therapy.

Photodynamic therapy (PDT) involves the administration of a photosensitizer, followed by local irradiation of tumor tissues using a laser of an appropriate wavelength to activate the photosensitizer. Since multiple cellular signaling cascades are concomitantly activated in cancer cells exposed to the photodynamic effect, understanding the responses of cancer cells to PDT will aid in the development of new interventions. This review describes the possible cell-death signaling pathways initiated by PDT. In addition, we describe our latest findings regarding the induction of expression of miRNAs specific to apoptosis in cancer cells and the induction of antitumor immunity following PDT against cancer cells. A more detailed understanding of the molecular mechanisms related to PDT will potentially improve long-term survival of PDT treated patients.