Quian Peng (Photodynamic Therapy)
Group Leader: Quian Peng Ph.D.
Group Members:
Jahn M. Nesland (Prof. Head of the Department)
Beata Cunderlikova (Postdoc.)
Ingegerd E. Furre (PhD student)
Susan Shahzidi (PhD student)
Vlada Vasovic (Research associate)
Photodynamic therapy (PDT) is a two-step therapeutic technique in which the topical or systemic delivery of a photosensitizing drug is followed by irradiation with visible light. The activated photosensitizer transfers energy to molecular oxygen, generating reactive oxygen species (ROS). The subsequent oxidation of lipids, amino-acids and proteins induces cell necrosis and apoptosis. This group has been working on the projects of PDT for more than 10 years. In 2006, research focused largely on mechanistic studies as follows:
PDT-induced tissue hypoxia as a result of vascular damage and photochemical oxygen consumption limits the efficacy of this modality. This may largely be due to hypoxia-mediated angiogenesis via hypoxia-inducible factor-1 (HIF-1), a major transcription factor involved in angiogenesis, hematopoiesis and anaerobic energy metabolism. High expression of HIF-1 induced in vitro by cobalt chloride (CoCl2)-mediated chemical hypoxia mimic was seen in the Het-1A cell line. The CoCl2-treated cells were more resistant to PDT than those without CoCl2 treatment. The photosensitivity of the cells to PDT decreased with increasing HIF-1 expression by enhancing CoCl2 concentrations. Moreover, transfection of the cells with anti-HIF-1 short interfering RNA (siRNA) knocked down the HIF-1 expression and restored the photosensitivity of the cells to PDT. The finding suggests that PDT in combination with anti-HIF-1 treatment may enhance the PDT efficacy.