With photodynamic therapy (PDT), “no matter what you do, if you are lucky, there is a prodeath response,” stated Tayyaba Hasan, PhD, of the Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston. However, “simultaneously, there is a prosurvival molecular response, which mitigates the desired outcome with PDT,” she continued. Simply put, these opposing molecular responses are at the heart of the challenge for basic science researchers and clinicians to enhance the photodynamic effect.
In this article, Dr. Hasan explores the preclinical research findings on molecular targets that serve as the clinical foundation for moving PDT forward into the future, essentially in combination treatment. First, the molecular response to PDT in prostate, pancreatic, and ovarian cancer cell models is discussed, featuring the roles of both vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) in guiding the selection of targeted agents to join PDT in combination. Second, the role of preconditioning via nuclear receptor targets, such as vitamin D and retinoic acid, before PDT to improve the photodynamic effect is briefly addressed.
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